drivers/md/raid5.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * raid5.c : Multiple Devices driver for Linux
   4  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   5  *         Copyright (C) 1999, 2000 Ingo Molnar
   6  *         Copyright (C) 2002, 2003 H. Peter Anvin
   7  *
   8  * RAID-4/5/6 management functions.
   9  * Thanks to Penguin Computing for making the RAID-6 development possible
  10  * by donating a test server!
  11  */
  12
  13 /*
  14  * BITMAP UNPLUGGING:
  15  *
  16  * The sequencing for updating the bitmap reliably is a little
  17  * subtle (and I got it wrong the first time) so it deserves some
  18  * explanation.
  19  *
  20  * We group bitmap updates into batches.  Each batch has a number.
  21  * We may write out several batches at once, but that isn't very important.
  22  * conf->seq_write is the number of the last batch successfully written.
  23  * conf->seq_flush is the number of the last batch that was closed to
  24  *    new additions.
  25  * When we discover that we will need to write to any block in a stripe
  26  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  27  * the number of the batch it will be in. This is seq_flush+1.
  28  * When we are ready to do a write, if that batch hasn't been written yet,
  29  *   we plug the array and queue the stripe for later.
  30  * When an unplug happens, we increment bm_flush, thus closing the current
  31  *   batch.
  32  * When we notice that bm_flush > bm_write, we write out all pending updates
  33  * to the bitmap, and advance bm_write to where bm_flush was.
  34  * This may occasionally write a bit out twice, but is sure never to
  35  * miss any bits.
  36  */
  37
  38 #include <linux/blkdev.h>
  39 #include <linux/kthread.h>
  40 #include <linux/raid/pq.h>
  41 #include <linux/async_tx.h>
  42 #include <linux/module.h>
  43 #include <linux/async.h>
  44 #include <linux/seq_file.h>
  45 #include <linux/cpu.h>
  46 #include <linux/slab.h>
  47 #include <linux/ratelimit.h>
  48 #include <linux/nodemask.h>
  49
  50 #include <trace/events/block.h>
  51 #include <linux/list_sort.h>
  52
  53 #include "md.h"
  54 #include "raid5.h"
  55 #include "raid0.h"
  56 #include "md-bitmap.h"
  57 #include "raid5-log.h"
  58
  59 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  60
  61 #define cpu_to_group(cpu) cpu_to_node(cpu)
  62 #define ANY_GROUP NUMA_NO_NODE
  63
  64 #define RAID5_MAX_REQ_STRIPES 256
  65
  66 static bool devices_handle_discard_safely = false;
  67 module_param(devices_handle_discard_safely, bool, 0644);
  68 MODULE_PARM_DESC(devices_handle_discard_safely,
  69                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  70 static struct workqueue_struct *raid5_wq;
  71
  72 static void raid5_quiesce(struct mddev *mddev, int quiesce);
  73
  74 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  75 {
  76         int hash = (sect >> RAID5_STRIPE_SHIFT(conf)) & HASH_MASK;
  77         return &conf->stripe_hashtbl[hash];
  78 }
  79
  80 static inline int stripe_hash_locks_hash(struct r5conf *conf, sector_t sect)
  81 {
  82         return (sect >> RAID5_STRIPE_SHIFT(conf)) & STRIPE_HASH_LOCKS_MASK;
  83 }
  84
  85 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  86         __acquires(&conf->device_lock)
  87 {
  88         spin_lock_irq(conf->hash_locks + hash);
  89         spin_lock(&conf->device_lock);
  90 }
  91
  92 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  93         __releases(&conf->device_lock)
  94 {
  95         spin_unlock(&conf->device_lock);
  96         spin_unlock_irq(conf->hash_locks + hash);
  97 }
  98
  99 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
 100         __acquires(&conf->device_lock)
 101 {
 102         int i;
 103         spin_lock_irq(conf->hash_locks);
 104         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 105                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 106         spin_lock(&conf->device_lock);
 107 }
 108
 109 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 110         __releases(&conf->device_lock)
 111 {
 112         int i;
 113         spin_unlock(&conf->device_lock);
 114         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 115                 spin_unlock(conf->hash_locks + i);
 116         spin_unlock_irq(conf->hash_locks);
 117 }
 118
 119 /* Find first data disk in a raid6 stripe */
 120 static inline int raid6_d0(struct stripe_head *sh)
 121 {
 122         if (sh->ddf_layout)
 123                 /* ddf always start from first device */
 124                 return 0;
 125         /* md starts just after Q block */
 126         if (sh->qd_idx == sh->disks - 1)
 127                 return 0;
 128         else
 129                 return sh->qd_idx + 1;
 130 }
 131 static inline int raid6_next_disk(int disk, int raid_disks)
 132 {
 133         disk++;
 134         return (disk < raid_disks) ? disk : 0;
 135 }
 136
 137 /* When walking through the disks in a raid5, starting at raid6_d0,
 138  * We need to map each disk to a 'slot', where the data disks are slot
 139  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 140  * is raid_disks-1.  This help does that mapping.
 141  */
 142 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 143                              int *count, int syndrome_disks)
 144 {
 145         int slot = *count;
 146
 147         if (sh->ddf_layout)
 148                 (*count)++;
 149         if (idx == sh->pd_idx)
 150                 return syndrome_disks;
 151         if (idx == sh->qd_idx)
 152                 return syndrome_disks + 1;
 153         if (!sh->ddf_layout)
 154                 (*count)++;
 155         return slot;
 156 }
 157
 158 static void print_raid5_conf(struct r5conf *conf);
 159
 160 static int stripe_operations_active(struct stripe_head *sh)
 161 {
 162         return sh->check_state || sh->reconstruct_state ||
 163                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 164                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 165 }
 166
 167 static bool stripe_is_lowprio(struct stripe_head *sh)
 168 {
 169         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 170                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 171                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 172 }
 173
 174 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 175         __must_hold(&sh->raid_conf->device_lock)
 176 {
 177         struct r5conf *conf = sh->raid_conf;
 178         struct r5worker_group *group;
 179         int thread_cnt;
 180         int i, cpu = sh->cpu;
 181
 182         if (!cpu_online(cpu)) {
 183                 cpu = cpumask_any(cpu_online_mask);
 184                 sh->cpu = cpu;
 185         }
 186
 187         if (list_empty(&sh->lru)) {
 188                 struct r5worker_group *group;
 189                 group = conf->worker_groups + cpu_to_group(cpu);
 190                 if (stripe_is_lowprio(sh))
 191                         list_add_tail(&sh->lru, &group->loprio_list);
 192                 else
 193                         list_add_tail(&sh->lru, &group->handle_list);
 194                 group->stripes_cnt++;
 195                 sh->group = group;
 196         }
 197
 198         if (conf->worker_cnt_per_group == 0) {
 199                 md_wakeup_thread(conf->mddev->thread);
 200                 return;
 201         }
 202
 203         group = conf->worker_groups + cpu_to_group(sh->cpu);
 204
 205         group->workers[0].working = true;
 206         /* at least one worker should run to avoid race */
 207         queue_work_on(sh->cpu, raid5_wq, &group->workers[0].work);
 208
 209         thread_cnt = group->stripes_cnt / MAX_STRIPE_BATCH - 1;
 210         /* wakeup more workers */
 211         for (i = 1; i < conf->worker_cnt_per_group && thread_cnt > 0; i++) {
 212                 if (group->workers[i].working == false) {
 213                         group->workers[i].working = true;
 214                         queue_work_on(sh->cpu, raid5_wq,
 215                                       &group->workers[i].work);
 216                         thread_cnt--;
 217                 }
 218         }
 219 }
 220
 221 static void do_release_stripe(struct r5conf *conf, struct stripe_head *sh,
 222                               struct list_head *temp_inactive_list)
 223         __must_hold(&conf->device_lock)
 224 {
 225         int i;
 226         int injournal = 0;      /* number of date pages with R5_InJournal */
 227
 228         BUG_ON(!list_empty(&sh->lru));
 229         BUG_ON(atomic_read(&conf->active_stripes)==0);
 230
 231         if (r5c_is_writeback(conf->log))
 232                 for (i = sh->disks; i--; )
 233                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 234                                 injournal++;
 235         /*
 236          * In the following cases, the stripe cannot be released to cached
 237          * lists. Therefore, we make the stripe write out and set
 238          * STRIPE_HANDLE:
 239          *   1. when quiesce in r5c write back;
 240          *   2. when resync is requested fot the stripe.
 241          */
 242         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 243             (conf->quiesce && r5c_is_writeback(conf->log) &&
 244              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 245                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 246                         r5c_make_stripe_write_out(sh);
 247                 set_bit(STRIPE_HANDLE, &sh->state);
 248         }
 249
 250         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 251                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 252                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 253                         list_add_tail(&sh->lru, &conf->delayed_list);
 254                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 255                            sh->bm_seq - conf->seq_write > 0)
 256                         list_add_tail(&sh->lru, &conf->bitmap_list);
 257                 else {
 258                         clear_bit(STRIPE_DELAYED, &sh->state);
 259                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 260                         if (conf->worker_cnt_per_group == 0) {
 261                                 if (stripe_is_lowprio(sh))
 262                                         list_add_tail(&sh->lru,
 263                                                         &conf->loprio_list);
 264                                 else
 265                                         list_add_tail(&sh->lru,
 266                                                         &conf->handle_list);
 267                         } else {
 268                                 raid5_wakeup_stripe_thread(sh);
 269                                 return;
 270                         }
 271                 }
 272                 md_wakeup_thread(conf->mddev->thread);
 273         } else {
 274                 BUG_ON(stripe_operations_active(sh));
 275                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 276                         if (atomic_dec_return(&conf->preread_active_stripes)
 277                             < IO_THRESHOLD)
 278                                 md_wakeup_thread(conf->mddev->thread);
 279                 atomic_dec(&conf->active_stripes);
 280                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 281                         if (!r5c_is_writeback(conf->log))
 282                                 list_add_tail(&sh->lru, temp_inactive_list);
 283                         else {
 284                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 285                                 if (injournal == 0)
 286                                         list_add_tail(&sh->lru, temp_inactive_list);
 287                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 288                                         /* full stripe */
 289                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 290                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 291                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 292                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 293                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 294                                         r5c_check_cached_full_stripe(conf);
 295                                 } else
 296                                         /*
 297                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 298                                          * r5c_try_caching_write(). No need to
 299                                          * set it again.
 300                                          */
 301                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 302                         }
 303                 }
 304         }
 305 }
 306
 307 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 308                              struct list_head *temp_inactive_list)
 309         __must_hold(&conf->device_lock)
 310 {
 311         if (atomic_dec_and_test(&sh->count))
 312                 do_release_stripe(conf, sh, temp_inactive_list);
 313 }
 314
 315 /*
 316  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 317  *
 318  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 319  * given time. Adding stripes only takes device lock, while deleting stripes
 320  * only takes hash lock.
 321  */
 322 static void release_inactive_stripe_list(struct r5conf *conf,
 323                                          struct list_head *temp_inactive_list,
 324                                          int hash)
 325 {
 326         int size;
 327         bool do_wakeup = false;
 328         unsigned long flags;
 329
 330         if (hash == NR_STRIPE_HASH_LOCKS) {
 331                 size = NR_STRIPE_HASH_LOCKS;
 332                 hash = NR_STRIPE_HASH_LOCKS - 1;
 333         } else
 334                 size = 1;
 335         while (size) {
 336                 struct list_head *list = &temp_inactive_list[size - 1];
 337
 338                 /*
 339                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 340                  * remove stripes from the list
 341                  */
 342                 if (!list_empty_careful(list)) {
 343                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 344                         if (list_empty(conf->inactive_list + hash) &&
 345                             !list_empty(list))
 346                                 atomic_dec(&conf->empty_inactive_list_nr);
 347                         list_splice_tail_init(list, conf->inactive_list + hash);
 348                         do_wakeup = true;
 349                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 350                 }
 351                 size--;
 352                 hash--;
 353         }
 354
 355         if (do_wakeup) {
 356                 wake_up(&conf->wait_for_stripe);
 357                 if (atomic_read(&conf->active_stripes) == 0)
 358                         wake_up(&conf->wait_for_quiescent);
 359                 if (conf->retry_read_aligned)
 360                         md_wakeup_thread(conf->mddev->thread);
 361         }
 362 }
 363
 364 static int release_stripe_list(struct r5conf *conf,
 365                                struct list_head *temp_inactive_list)
 366         __must_hold(&conf->device_lock)
 367 {
 368         struct stripe_head *sh, *t;
 369         int count = 0;
 370         struct llist_node *head;
 371
 372         head = llist_del_all(&conf->released_stripes);
 373         head = llist_reverse_order(head);
 374         llist_for_each_entry_safe(sh, t, head, release_list) {
 375                 int hash;
 376
 377                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 378                 smp_mb();
 379                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 380                 /*
 381                  * Don't worry the bit is set here, because if the bit is set
 382                  * again, the count is always > 1. This is true for
 383                  * STRIPE_ON_UNPLUG_LIST bit too.
 384                  */
 385                 hash = sh->hash_lock_index;
 386                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 387                 count++;
 388         }
 389
 390         return count;
 391 }
 392
 393 void raid5_release_stripe(struct stripe_head *sh)
 394 {
 395         struct r5conf *conf = sh->raid_conf;
 396         unsigned long flags;
 397         struct list_head list;
 398         int hash;
 399         bool wakeup;
 400
 401         /* Avoid release_list until the last reference.
 402          */
 403         if (atomic_add_unless(&sh->count, -1, 1))
 404                 return;
 405
 406         if (unlikely(!conf->mddev->thread) ||
 407                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 408                 goto slow_path;
 409         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 410         if (wakeup)
 411                 md_wakeup_thread(conf->mddev->thread);
 412         return;
 413 slow_path:
 414         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 415         if (atomic_dec_and_lock_irqsave(&sh->count, &conf->device_lock, flags)) {
 416                 INIT_LIST_HEAD(&list);
 417                 hash = sh->hash_lock_index;
 418                 do_release_stripe(conf, sh, &list);
 419                 spin_unlock_irqrestore(&conf->device_lock, flags);
 420                 release_inactive_stripe_list(conf, &list, hash);
 421         }
 422 }
 423
 424 static inline void remove_hash(struct stripe_head *sh)
 425 {
 426         pr_debug("remove_hash(), stripe %llu\n",
 427                 (unsigned long long)sh->sector);
 428
 429         hlist_del_init(&sh->hash);
 430 }
 431
 432 static inline void insert_hash(struct r5conf *conf, struct stripe_head *sh)
 433 {
 434         struct hlist_head *hp = stripe_hash(conf, sh->sector);
 435
 436         pr_debug("insert_hash(), stripe %llu\n",
 437                 (unsigned long long)sh->sector);
 438
 439         hlist_add_head(&sh->hash, hp);
 440 }
 441
 442 /* find an idle stripe, make sure it is unhashed, and return it. */
 443 static struct stripe_head *get_free_stripe(struct r5conf *conf, int hash)
 444 {
 445         struct stripe_head *sh = NULL;
 446         struct list_head *first;
 447
 448         if (list_empty(conf->inactive_list + hash))
 449                 goto out;
 450         first = (conf->inactive_list + hash)->next;
 451         sh = list_entry(first, struct stripe_head, lru);
 452         list_del_init(first);
 453         remove_hash(sh);
 454         atomic_inc(&conf->active_stripes);
 455         BUG_ON(hash != sh->hash_lock_index);
 456         if (list_empty(conf->inactive_list + hash))
 457                 atomic_inc(&conf->empty_inactive_list_nr);
 458 out:
 459         return sh;
 460 }
 461
 462 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
 463 static void free_stripe_pages(struct stripe_head *sh)
 464 {
 465         int i;
 466         struct page *p;
 467
 468         /* Have not allocate page pool */
 469         if (!sh->pages)
 470                 return;
 471
 472         for (i = 0; i < sh->nr_pages; i++) {
 473                 p = sh->pages[i];
 474                 if (p)
 475                         put_page(p);
 476                 sh->pages[i] = NULL;
 477         }
 478 }
 479
 480 static int alloc_stripe_pages(struct stripe_head *sh, gfp_t gfp)
 481 {
 482         int i;
 483         struct page *p;
 484
 485         for (i = 0; i < sh->nr_pages; i++) {
 486                 /* The page have allocated. */
 487                 if (sh->pages[i])
 488                         continue;
 489
 490                 p = alloc_page(gfp);
 491                 if (!p) {
 492                         free_stripe_pages(sh);
 493                         return -ENOMEM;
 494                 }
 495                 sh->pages[i] = p;
 496         }
 497         return 0;
 498 }
 499
 500 static int
 501 init_stripe_shared_pages(struct stripe_head *sh, struct r5conf *conf, int disks)
 502 {
 503         int nr_pages, cnt;
 504
 505         if (sh->pages)
 506                 return 0;
 507
 508         /* Each of the sh->dev[i] need one conf->stripe_size */
 509         cnt = PAGE_SIZE / conf->stripe_size;
 510         nr_pages = (disks + cnt - 1) / cnt;
 511
 512         sh->pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
 513         if (!sh->pages)
 514                 return -ENOMEM;
 515         sh->nr_pages = nr_pages;
 516         sh->stripes_per_page = cnt;
 517         return 0;
 518 }
 519 #endif
 520
 521 static void shrink_buffers(struct stripe_head *sh)
 522 {
 523         int i;
 524         int num = sh->raid_conf->pool_size;
 525
 526 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 527         for (i = 0; i < num ; i++) {
 528                 struct page *p;
 529
 530                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 531                 p = sh->dev[i].page;
 532                 if (!p)
 533                         continue;
 534                 sh->dev[i].page = NULL;
 535                 put_page(p);
 536         }
 537 #else
 538         for (i = 0; i < num; i++)
 539                 sh->dev[i].page = NULL;
 540         free_stripe_pages(sh); /* Free pages */
 541 #endif
 542 }
 543
 544 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 545 {
 546         int i;
 547         int num = sh->raid_conf->pool_size;
 548
 549 #if PAGE_SIZE == DEFAULT_STRIPE_SIZE
 550         for (i = 0; i < num; i++) {
 551                 struct page *page;
 552
 553                 if (!(page = alloc_page(gfp))) {
 554                         return 1;
 555                 }
 556                 sh->dev[i].page = page;
 557                 sh->dev[i].orig_page = page;
 558                 sh->dev[i].offset = 0;
 559         }
 560 #else
 561         if (alloc_stripe_pages(sh, gfp))
 562                 return -ENOMEM;
 563
 564         for (i = 0; i < num; i++) {
 565                 sh->dev[i].page = raid5_get_dev_page(sh, i);
 566                 sh->dev[i].orig_page = sh->dev[i].page;
 567                 sh->dev[i].offset = raid5_get_page_offset(sh, i);
 568         }
 569 #endif
 570         return 0;
 571 }
 572
 573 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 574                             struct stripe_head *sh);
 575
 576 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 577 {
 578         struct r5conf *conf = sh->raid_conf;
 579         int i, seq;
 580
 581         BUG_ON(atomic_read(&sh->count) != 0);
 582         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 583         BUG_ON(stripe_operations_active(sh));
 584         BUG_ON(sh->batch_head);
 585
 586         pr_debug("init_stripe called, stripe %llu\n",
 587                 (unsigned long long)sector);
 588 retry:
 589         seq = read_seqcount_begin(&conf->gen_lock);
 590         sh->generation = conf->generation - previous;
 591         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 592         sh->sector = sector;
 593         stripe_set_idx(sector, conf, previous, sh);
 594         sh->state = 0;
 595
 596         for (i = sh->disks; i--; ) {
 597                 struct r5dev *dev = &sh->dev[i];
 598
 599                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 600                     test_bit(R5_LOCKED, &dev->flags)) {
 601                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 602                                (unsigned long long)sh->sector, i, dev->toread,
 603                                dev->read, dev->towrite, dev->written,
 604                                test_bit(R5_LOCKED, &dev->flags));
 605                         WARN_ON(1);
 606                 }
 607                 dev->flags = 0;
 608                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 609         }
 610         if (read_seqcount_retry(&conf->gen_lock, seq))
 611                 goto retry;
 612         sh->overwrite_disks = 0;
 613         insert_hash(conf, sh);
 614         sh->cpu = smp_processor_id();
 615         set_bit(STRIPE_BATCH_READY, &sh->state);
 616 }
 617
 618 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 619                                          short generation)
 620 {
 621         struct stripe_head *sh;
 622
 623         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 624         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 625                 if (sh->sector == sector && sh->generation == generation)
 626                         return sh;
 627         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 628         return NULL;
 629 }
 630
 631 static struct stripe_head *find_get_stripe(struct r5conf *conf,
 632                 sector_t sector, short generation, int hash)
 633 {
 634         int inc_empty_inactive_list_flag;
 635         struct stripe_head *sh;
 636
 637         sh = __find_stripe(conf, sector, generation);
 638         if (!sh)
 639                 return NULL;
 640
 641         if (atomic_inc_not_zero(&sh->count))
 642                 return sh;
 643
 644         /*
 645          * Slow path. The reference count is zero which means the stripe must
 646          * be on a list (sh->lru). Must remove the stripe from the list that
 647          * references it with the device_lock held.
 648          */
 649
 650         spin_lock(&conf->device_lock);
 651         if (!atomic_read(&sh->count)) {
 652                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 653                         atomic_inc(&conf->active_stripes);
 654                 BUG_ON(list_empty(&sh->lru) &&
 655                        !test_bit(STRIPE_EXPANDING, &sh->state));
 656                 inc_empty_inactive_list_flag = 0;
 657                 if (!list_empty(conf->inactive_list + hash))
 658                         inc_empty_inactive_list_flag = 1;
 659                 list_del_init(&sh->lru);
 660                 if (list_empty(conf->inactive_list + hash) &&
 661                     inc_empty_inactive_list_flag)
 662                         atomic_inc(&conf->empty_inactive_list_nr);
 663                 if (sh->group) {
 664                         sh->group->stripes_cnt--;
 665                         sh->group = NULL;
 666                 }
 667         }
 668         atomic_inc(&sh->count);
 669         spin_unlock(&conf->device_lock);
 670
 671         return sh;
 672 }
 673
 674 /*
 675  * Need to check if array has failed when deciding whether to:
 676  *  - start an array
 677  *  - remove non-faulty devices
 678  *  - add a spare
 679  *  - allow a reshape
 680  * This determination is simple when no reshape is happening.
 681  * However if there is a reshape, we need to carefully check
 682  * both the before and after sections.
 683  * This is because some failed devices may only affect one
 684  * of the two sections, and some non-in_sync devices may
 685  * be insync in the section most affected by failed devices.
 686  *
 687  * Most calls to this function hold &conf->device_lock. Calls
 688  * in raid5_run() do not require the lock as no other threads
 689  * have been started yet.
 690  */
 691 int raid5_calc_degraded(struct r5conf *conf)
 692 {
 693         int degraded, degraded2;
 694         int i;
 695
 696         degraded = 0;
 697         for (i = 0; i < conf->previous_raid_disks; i++) {
 698                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
 699
 700                 if (rdev && test_bit(Faulty, &rdev->flags))
 701                         rdev = READ_ONCE(conf->disks[i].replacement);
 702                 if (!rdev || test_bit(Faulty, &rdev->flags))
 703                         degraded++;
 704                 else if (test_bit(In_sync, &rdev->flags))
 705                         ;
 706                 else
 707                         /* not in-sync or faulty.
 708                          * If the reshape increases the number of devices,
 709                          * this is being recovered by the reshape, so
 710                          * this 'previous' section is not in_sync.
 711                          * If the number of devices is being reduced however,
 712                          * the device can only be part of the array if
 713                          * we are reverting a reshape, so this section will
 714                          * be in-sync.
 715                          */
 716                         if (conf->raid_disks >= conf->previous_raid_disks)
 717                                 degraded++;
 718         }
 719         if (conf->raid_disks == conf->previous_raid_disks)
 720                 return degraded;
 721         degraded2 = 0;
 722         for (i = 0; i < conf->raid_disks; i++) {
 723                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
 724
 725                 if (rdev && test_bit(Faulty, &rdev->flags))
 726                         rdev = READ_ONCE(conf->disks[i].replacement);
 727                 if (!rdev || test_bit(Faulty, &rdev->flags))
 728                         degraded2++;
 729                 else if (test_bit(In_sync, &rdev->flags))
 730                         ;
 731                 else
 732                         /* not in-sync or faulty.
 733                          * If reshape increases the number of devices, this
 734                          * section has already been recovered, else it
 735                          * almost certainly hasn't.
 736                          */
 737                         if (conf->raid_disks <= conf->previous_raid_disks)
 738                                 degraded2++;
 739         }
 740         if (degraded2 > degraded)
 741                 return degraded2;
 742         return degraded;
 743 }
 744
 745 static bool has_failed(struct r5conf *conf)
 746 {
 747         int degraded = conf->mddev->degraded;
 748
 749         if (test_bit(MD_BROKEN, &conf->mddev->flags))
 750                 return true;
 751
 752         if (conf->mddev->reshape_position != MaxSector)
 753                 degraded = raid5_calc_degraded(conf);
 754
 755         return degraded > conf->max_degraded;
 756 }
 757
 758 enum stripe_result {
 759         STRIPE_SUCCESS = 0,
 760         STRIPE_RETRY,
 761         STRIPE_SCHEDULE_AND_RETRY,
 762         STRIPE_FAIL,
 763         STRIPE_WAIT_RESHAPE,
 764 };
 765
 766 struct stripe_request_ctx {
 767         /* a reference to the last stripe_head for batching */
 768         struct stripe_head *batch_last;
 769
 770         /* first sector in the request */
 771         sector_t first_sector;
 772
 773         /* last sector in the request */
 774         sector_t last_sector;
 775
 776         /*
 777          * bitmap to track stripe sectors that have been added to stripes
 778          * add one to account for unaligned requests
 779          */
 780         DECLARE_BITMAP(sectors_to_do, RAID5_MAX_REQ_STRIPES + 1);
 781
 782         /* the request had REQ_PREFLUSH, cleared after the first stripe_head */
 783         bool do_flush;
 784 };
 785
 786 /*
 787  * Block until another thread clears R5_INACTIVE_BLOCKED or
 788  * there are fewer than 3/4 the maximum number of active stripes
 789  * and there is an inactive stripe available.
 790  */
 791 static bool is_inactive_blocked(struct r5conf *conf, int hash)
 792 {
 793         if (list_empty(conf->inactive_list + hash))
 794                 return false;
 795
 796         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
 797                 return true;
 798
 799         return (atomic_read(&conf->active_stripes) <
 800                 (conf->max_nr_stripes * 3 / 4));
 801 }
 802
 803 struct stripe_head *raid5_get_active_stripe(struct r5conf *conf,
 804                 struct stripe_request_ctx *ctx, sector_t sector,
 805                 unsigned int flags)
 806 {
 807         struct stripe_head *sh;
 808         int hash = stripe_hash_locks_hash(conf, sector);
 809         int previous = !!(flags & R5_GAS_PREVIOUS);
 810
 811         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 812
 813         spin_lock_irq(conf->hash_locks + hash);
 814
 815         for (;;) {
 816                 if (!(flags & R5_GAS_NOQUIESCE) && conf->quiesce) {
 817                         /*
 818                          * Must release the reference to batch_last before
 819                          * waiting, on quiesce, otherwise the batch_last will
 820                          * hold a reference to a stripe and raid5_quiesce()
 821                          * will deadlock waiting for active_stripes to go to
 822                          * zero.
 823                          */
 824                         if (ctx && ctx->batch_last) {
 825                                 raid5_release_stripe(ctx->batch_last);
 826                                 ctx->batch_last = NULL;
 827                         }
 828
 829                         wait_event_lock_irq(conf->wait_for_quiescent,
 830                                             !conf->quiesce,
 831                                             *(conf->hash_locks + hash));
 832                 }
 833
 834                 sh = find_get_stripe(conf, sector, conf->generation - previous,
 835                                      hash);
 836                 if (sh)
 837                         break;
 838
 839                 if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 840                         sh = get_free_stripe(conf, hash);
 841                         if (sh) {
 842                                 r5c_check_stripe_cache_usage(conf);
 843                                 init_stripe(sh, sector, previous);
 844                                 atomic_inc(&sh->count);
 845                                 break;
 846                         }
 847
 848                         if (!test_bit(R5_DID_ALLOC, &conf->cache_state))
 849                                 set_bit(R5_ALLOC_MORE, &conf->cache_state);
 850                 }
 851
 852                 if (flags & R5_GAS_NOBLOCK)
 853                         break;
 854
 855                 set_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 856                 r5l_wake_reclaim(conf->log, 0);
 857
 858                 /* release batch_last before wait to avoid risk of deadlock */
 859                 if (ctx && ctx->batch_last) {
 860                         raid5_release_stripe(ctx->batch_last);
 861                         ctx->batch_last = NULL;
 862                 }
 863
 864                 wait_event_lock_irq(conf->wait_for_stripe,
 865                                     is_inactive_blocked(conf, hash),
 866                                     *(conf->hash_locks + hash));
 867                 clear_bit(R5_INACTIVE_BLOCKED, &conf->cache_state);
 868         }
 869
 870         spin_unlock_irq(conf->hash_locks + hash);
 871         return sh;
 872 }
 873
 874 static bool is_full_stripe_write(struct stripe_head *sh)
 875 {
 876         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 877         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 878 }
 879
 880 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 881                 __acquires(&sh1->stripe_lock)
 882                 __acquires(&sh2->stripe_lock)
 883 {
 884         if (sh1 > sh2) {
 885                 spin_lock_irq(&sh2->stripe_lock);
 886                 spin_lock_nested(&sh1->stripe_lock, 1);
 887         } else {
 888                 spin_lock_irq(&sh1->stripe_lock);
 889                 spin_lock_nested(&sh2->stripe_lock, 1);
 890         }
 891 }
 892
 893 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 894                 __releases(&sh1->stripe_lock)
 895                 __releases(&sh2->stripe_lock)
 896 {
 897         spin_unlock(&sh1->stripe_lock);
 898         spin_unlock_irq(&sh2->stripe_lock);
 899 }
 900
 901 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 902 static bool stripe_can_batch(struct stripe_head *sh)
 903 {
 904         struct r5conf *conf = sh->raid_conf;
 905
 906         if (raid5_has_log(conf) || raid5_has_ppl(conf))
 907                 return false;
 908         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 909                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 910                 is_full_stripe_write(sh);
 911 }
 912
 913 /* we only do back search */
 914 static void stripe_add_to_batch_list(struct r5conf *conf,
 915                 struct stripe_head *sh, struct stripe_head *last_sh)
 916 {
 917         struct stripe_head *head;
 918         sector_t head_sector, tmp_sec;
 919         int hash;
 920         int dd_idx;
 921
 922         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 923         tmp_sec = sh->sector;
 924         if (!sector_div(tmp_sec, conf->chunk_sectors))
 925                 return;
 926         head_sector = sh->sector - RAID5_STRIPE_SECTORS(conf);
 927
 928         if (last_sh && head_sector == last_sh->sector) {
 929                 head = last_sh;
 930                 atomic_inc(&head->count);
 931         } else {
 932                 hash = stripe_hash_locks_hash(conf, head_sector);
 933                 spin_lock_irq(conf->hash_locks + hash);
 934                 head = find_get_stripe(conf, head_sector, conf->generation,
 935                                        hash);
 936                 spin_unlock_irq(conf->hash_locks + hash);
 937                 if (!head)
 938                         return;
 939                 if (!stripe_can_batch(head))
 940                         goto out;
 941         }
 942
 943         lock_two_stripes(head, sh);
 944         /* clear_batch_ready clear the flag */
 945         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 946                 goto unlock_out;
 947
 948         if (sh->batch_head)
 949                 goto unlock_out;
 950
 951         dd_idx = 0;
 952         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 953                 dd_idx++;
 954         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 955             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 956                 goto unlock_out;
 957
 958         if (head->batch_head) {
 959                 spin_lock(&head->batch_head->batch_lock);
 960                 /* This batch list is already running */
 961                 if (!stripe_can_batch(head)) {
 962                         spin_unlock(&head->batch_head->batch_lock);
 963                         goto unlock_out;
 964                 }
 965                 /*
 966                  * We must assign batch_head of this stripe within the
 967                  * batch_lock, otherwise clear_batch_ready of batch head
 968                  * stripe could clear BATCH_READY bit of this stripe and
 969                  * this stripe->batch_head doesn't get assigned, which
 970                  * could confuse clear_batch_ready for this stripe
 971                  */
 972                 sh->batch_head = head->batch_head;
 973
 974                 /*
 975                  * at this point, head's BATCH_READY could be cleared, but we
 976                  * can still add the stripe to batch list
 977                  */
 978                 list_add(&sh->batch_list, &head->batch_list);
 979                 spin_unlock(&head->batch_head->batch_lock);
 980         } else {
 981                 head->batch_head = head;
 982                 sh->batch_head = head->batch_head;
 983                 spin_lock(&head->batch_lock);
 984                 list_add_tail(&sh->batch_list, &head->batch_list);
 985                 spin_unlock(&head->batch_lock);
 986         }
 987
 988         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 989                 if (atomic_dec_return(&conf->preread_active_stripes)
 990                     < IO_THRESHOLD)
 991                         md_wakeup_thread(conf->mddev->thread);
 992
 993         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 994                 int seq = sh->bm_seq;
 995                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 996                     sh->batch_head->bm_seq > seq)
 997                         seq = sh->batch_head->bm_seq;
 998                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 999                 sh->batch_head->bm_seq = seq;
1000         }
1001
1002         atomic_inc(&sh->count);
1003 unlock_out:
1004         unlock_two_stripes(head, sh);
1005 out:
1006         raid5_release_stripe(head);
1007 }
1008
1009 /* Determine if 'data_offset' or 'new_data_offset' should be used
1010  * in this stripe_head.
1011  */
1012 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
1013 {
1014         sector_t progress = conf->reshape_progress;
1015         /* Need a memory barrier to make sure we see the value
1016          * of conf->generation, or ->data_offset that was set before
1017          * reshape_progress was updated.
1018          */
1019         smp_rmb();
1020         if (progress == MaxSector)
1021                 return 0;
1022         if (sh->generation == conf->generation - 1)
1023                 return 0;
1024         /* We are in a reshape, and this is a new-generation stripe,
1025          * so use new_data_offset.
1026          */
1027         return 1;
1028 }
1029
1030 static void dispatch_bio_list(struct bio_list *tmp)
1031 {
1032         struct bio *bio;
1033
1034         while ((bio = bio_list_pop(tmp)))
1035                 submit_bio_noacct(bio);
1036 }
1037
1038 static int cmp_stripe(void *priv, const struct list_head *a,
1039                       const struct list_head *b)
1040 {
1041         const struct r5pending_data *da = list_entry(a,
1042                                 struct r5pending_data, sibling);
1043         const struct r5pending_data *db = list_entry(b,
1044                                 struct r5pending_data, sibling);
1045         if (da->sector > db->sector)
1046                 return 1;
1047         if (da->sector < db->sector)
1048                 return -1;
1049         return 0;
1050 }
1051
1052 static void dispatch_defer_bios(struct r5conf *conf, int target,
1053                                 struct bio_list *list)
1054 {
1055         struct r5pending_data *data;
1056         struct list_head *first, *next = NULL;
1057         int cnt = 0;
1058
1059         if (conf->pending_data_cnt == 0)
1060                 return;
1061
1062         list_sort(NULL, &conf->pending_list, cmp_stripe);
1063
1064         first = conf->pending_list.next;
1065
1066         /* temporarily move the head */
1067         if (conf->next_pending_data)
1068                 list_move_tail(&conf->pending_list,
1069                                 &conf->next_pending_data->sibling);
1070
1071         while (!list_empty(&conf->pending_list)) {
1072                 data = list_first_entry(&conf->pending_list,
1073                         struct r5pending_data, sibling);
1074                 if (&data->sibling == first)
1075                         first = data->sibling.next;
1076                 next = data->sibling.next;
1077
1078                 bio_list_merge(list, &data->bios);
1079                 list_move(&data->sibling, &conf->free_list);
1080                 cnt++;
1081                 if (cnt >= target)
1082                         break;
1083         }
1084         conf->pending_data_cnt -= cnt;
1085         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
1086
1087         if (next != &conf->pending_list)
1088                 conf->next_pending_data = list_entry(next,
1089                                 struct r5pending_data, sibling);
1090         else
1091                 conf->next_pending_data = NULL;
1092         /* list isn't empty */
1093         if (first != &conf->pending_list)
1094                 list_move_tail(&conf->pending_list, first);
1095 }
1096
1097 static void flush_deferred_bios(struct r5conf *conf)
1098 {
1099         struct bio_list tmp = BIO_EMPTY_LIST;
1100
1101         if (conf->pending_data_cnt == 0)
1102                 return;
1103
1104         spin_lock(&conf->pending_bios_lock);
1105         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
1106         BUG_ON(conf->pending_data_cnt != 0);
1107         spin_unlock(&conf->pending_bios_lock);
1108
1109         dispatch_bio_list(&tmp);
1110 }
1111
1112 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
1113                                 struct bio_list *bios)
1114 {
1115         struct bio_list tmp = BIO_EMPTY_LIST;
1116         struct r5pending_data *ent;
1117
1118         spin_lock(&conf->pending_bios_lock);
1119         ent = list_first_entry(&conf->free_list, struct r5pending_data,
1120                                                         sibling);
1121         list_move_tail(&ent->sibling, &conf->pending_list);
1122         ent->sector = sector;
1123         bio_list_init(&ent->bios);
1124         bio_list_merge(&ent->bios, bios);
1125         conf->pending_data_cnt++;
1126         if (conf->pending_data_cnt >= PENDING_IO_MAX)
1127                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
1128
1129         spin_unlock(&conf->pending_bios_lock);
1130
1131         dispatch_bio_list(&tmp);
1132 }
1133
1134 static void
1135 raid5_end_read_request(struct bio *bi);
1136 static void
1137 raid5_end_write_request(struct bio *bi);
1138
1139 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
1140 {
1141         struct r5conf *conf = sh->raid_conf;
1142         int i, disks = sh->disks;
1143         struct stripe_head *head_sh = sh;
1144         struct bio_list pending_bios = BIO_EMPTY_LIST;
1145         struct r5dev *dev;
1146         bool should_defer;
1147
1148         might_sleep();
1149
1150         if (log_stripe(sh, s) == 0)
1151                 return;
1152
1153         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1154
1155         for (i = disks; i--; ) {
1156                 enum req_op op;
1157                 blk_opf_t op_flags = 0;
1158                 int replace_only = 0;
1159                 struct bio *bi, *rbi;
1160                 struct md_rdev *rdev, *rrdev = NULL;
1161
1162                 sh = head_sh;
1163                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1164                         op = REQ_OP_WRITE;
1165                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1166                                 op_flags = REQ_FUA;
1167                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1168                                 op = REQ_OP_DISCARD;
1169                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1170                         op = REQ_OP_READ;
1171                 else if (test_and_clear_bit(R5_WantReplace,
1172                                             &sh->dev[i].flags)) {
1173                         op = REQ_OP_WRITE;
1174                         replace_only = 1;
1175                 } else
1176                         continue;
1177                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1178                         op_flags |= REQ_SYNC;
1179
1180 again:
1181                 dev = &sh->dev[i];
1182                 bi = &dev->req;
1183                 rbi = &dev->rreq; /* For writing to replacement */
1184
1185                 rdev = conf->disks[i].rdev;
1186                 rrdev = conf->disks[i].replacement;
1187                 if (op_is_write(op)) {
1188                         if (replace_only)
1189                                 rdev = NULL;
1190                         if (rdev == rrdev)
1191                                 /* We raced and saw duplicates */
1192                                 rrdev = NULL;
1193                 } else {
1194                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1195                                 rdev = rrdev;
1196                         rrdev = NULL;
1197                 }
1198
1199                 if (rdev && test_bit(Faulty, &rdev->flags))
1200                         rdev = NULL;
1201                 if (rdev)
1202                         atomic_inc(&rdev->nr_pending);
1203                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1204                         rrdev = NULL;
1205                 if (rrdev)
1206                         atomic_inc(&rrdev->nr_pending);
1207
1208                 /* We have already checked bad blocks for reads.  Now
1209                  * need to check for writes.  We never accept write errors
1210                  * on the replacement, so we don't to check rrdev.
1211                  */
1212                 while (op_is_write(op) && rdev &&
1213                        test_bit(WriteErrorSeen, &rdev->flags)) {
1214                         int bad = rdev_has_badblock(rdev, sh->sector,
1215                                                     RAID5_STRIPE_SECTORS(conf));
1216                         if (!bad)
1217                                 break;
1218
1219                         if (bad < 0) {
1220                                 set_bit(BlockedBadBlocks, &rdev->flags);
1221                                 if (!conf->mddev->external &&
1222                                     conf->mddev->sb_flags) {
1223                                         /* It is very unlikely, but we might
1224                                          * still need to write out the
1225                                          * bad block log - better give it
1226                                          * a chance*/
1227                                         md_check_recovery(conf->mddev);
1228                                 }
1229                                 /*
1230                                  * Because md_wait_for_blocked_rdev
1231                                  * will dec nr_pending, we must
1232                                  * increment it first.
1233                                  */
1234                                 atomic_inc(&rdev->nr_pending);
1235                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1236                         } else {
1237                                 /* Acknowledged bad block - skip the write */
1238                                 rdev_dec_pending(rdev, conf->mddev);
1239                                 rdev = NULL;
1240                         }
1241                 }
1242
1243                 if (rdev) {
1244                         if (s->syncing || s->expanding || s->expanded
1245                             || s->replacing)
1246                                 md_sync_acct(rdev->bdev, RAID5_STRIPE_SECTORS(conf));
1247
1248                         set_bit(STRIPE_IO_STARTED, &sh->state);
1249
1250                         bio_init(bi, rdev->bdev, &dev->vec, 1, op | op_flags);
1251                         bi->bi_end_io = op_is_write(op)
1252                                 ? raid5_end_write_request
1253                                 : raid5_end_read_request;
1254                         bi->bi_private = sh;
1255
1256                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1257                                 __func__, (unsigned long long)sh->sector,
1258                                 bi->bi_opf, i);
1259                         atomic_inc(&sh->count);
1260                         if (sh != head_sh)
1261                                 atomic_inc(&head_sh->count);
1262                         if (use_new_offset(conf, sh))
1263                                 bi->bi_iter.bi_sector = (sh->sector
1264                                                  + rdev->new_data_offset);
1265                         else
1266                                 bi->bi_iter.bi_sector = (sh->sector
1267                                                  + rdev->data_offset);
1268                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1269                                 bi->bi_opf |= REQ_NOMERGE;
1270
1271                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1272                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1273
1274                         if (!op_is_write(op) &&
1275                             test_bit(R5_InJournal, &sh->dev[i].flags))
1276                                 /*
1277                                  * issuing read for a page in journal, this
1278                                  * must be preparing for prexor in rmw; read
1279                                  * the data into orig_page
1280                                  */
1281                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1282                         else
1283                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1284                         bi->bi_vcnt = 1;
1285                         bi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1286                         bi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1287                         bi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1288                         /*
1289                          * If this is discard request, set bi_vcnt 0. We don't
1290                          * want to confuse SCSI because SCSI will replace payload
1291                          */
1292                         if (op == REQ_OP_DISCARD)
1293                                 bi->bi_vcnt = 0;
1294                         if (rrdev)
1295                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1296
1297                         mddev_trace_remap(conf->mddev, bi, sh->dev[i].sector);
1298                         if (should_defer && op_is_write(op))
1299                                 bio_list_add(&pending_bios, bi);
1300                         else
1301                                 submit_bio_noacct(bi);
1302                 }
1303                 if (rrdev) {
1304                         if (s->syncing || s->expanding || s->expanded
1305                             || s->replacing)
1306                                 md_sync_acct(rrdev->bdev, RAID5_STRIPE_SECTORS(conf));
1307
1308                         set_bit(STRIPE_IO_STARTED, &sh->state);
1309
1310                         bio_init(rbi, rrdev->bdev, &dev->rvec, 1, op | op_flags);
1311                         BUG_ON(!op_is_write(op));
1312                         rbi->bi_end_io = raid5_end_write_request;
1313                         rbi->bi_private = sh;
1314
1315                         pr_debug("%s: for %llu schedule op %d on "
1316                                  "replacement disc %d\n",
1317                                 __func__, (unsigned long long)sh->sector,
1318                                 rbi->bi_opf, i);
1319                         atomic_inc(&sh->count);
1320                         if (sh != head_sh)
1321                                 atomic_inc(&head_sh->count);
1322                         if (use_new_offset(conf, sh))
1323                                 rbi->bi_iter.bi_sector = (sh->sector
1324                                                   + rrdev->new_data_offset);
1325                         else
1326                                 rbi->bi_iter.bi_sector = (sh->sector
1327                                                   + rrdev->data_offset);
1328                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1329                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1330                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1331                         rbi->bi_vcnt = 1;
1332                         rbi->bi_io_vec[0].bv_len = RAID5_STRIPE_SIZE(conf);
1333                         rbi->bi_io_vec[0].bv_offset = sh->dev[i].offset;
1334                         rbi->bi_iter.bi_size = RAID5_STRIPE_SIZE(conf);
1335                         /*
1336                          * If this is discard request, set bi_vcnt 0. We don't
1337                          * want to confuse SCSI because SCSI will replace payload
1338                          */
1339                         if (op == REQ_OP_DISCARD)
1340                                 rbi->bi_vcnt = 0;
1341                         mddev_trace_remap(conf->mddev, rbi, sh->dev[i].sector);
1342                         if (should_defer && op_is_write(op))
1343                                 bio_list_add(&pending_bios, rbi);
1344                         else
1345                                 submit_bio_noacct(rbi);
1346                 }
1347                 if (!rdev && !rrdev) {
1348                         if (op_is_write(op))
1349                                 set_bit(STRIPE_DEGRADED, &sh->state);
1350                         pr_debug("skip op %d on disc %d for sector %llu\n",
1351                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1352                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1353                         set_bit(STRIPE_HANDLE, &sh->state);
1354                 }
1355
1356                 if (!head_sh->batch_head)
1357                         continue;
1358                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1359                                       batch_list);
1360                 if (sh != head_sh)
1361                         goto again;
1362         }
1363
1364         if (should_defer && !bio_list_empty(&pending_bios))
1365                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1366 }
1367
1368 static struct dma_async_tx_descriptor *
1369 async_copy_data(int frombio, struct bio *bio, struct page **page,
1370         unsigned int poff, sector_t sector, struct dma_async_tx_descriptor *tx,
1371         struct stripe_head *sh, int no_skipcopy)
1372 {
1373         struct bio_vec bvl;
1374         struct bvec_iter iter;
1375         struct page *bio_page;
1376         int page_offset;
1377         struct async_submit_ctl submit;
1378         enum async_tx_flags flags = 0;
1379         struct r5conf *conf = sh->raid_conf;
1380
1381         if (bio->bi_iter.bi_sector >= sector)
1382                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1383         else
1384                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1385
1386         if (frombio)
1387                 flags |= ASYNC_TX_FENCE;
1388         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1389
1390         bio_for_each_segment(bvl, bio, iter) {
1391                 int len = bvl.bv_len;
1392                 int clen;
1393                 int b_offset = 0;
1394
1395                 if (page_offset < 0) {
1396                         b_offset = -page_offset;
1397                         page_offset += b_offset;
1398                         len -= b_offset;
1399                 }
1400
1401                 if (len > 0 && page_offset + len > RAID5_STRIPE_SIZE(conf))
1402                         clen = RAID5_STRIPE_SIZE(conf) - page_offset;
1403                 else
1404                         clen = len;
1405
1406                 if (clen > 0) {
1407                         b_offset += bvl.bv_offset;
1408                         bio_page = bvl.bv_page;
1409                         if (frombio) {
1410                                 if (conf->skip_copy &&
1411                                     b_offset == 0 && page_offset == 0 &&
1412                                     clen == RAID5_STRIPE_SIZE(conf) &&
1413                                     !no_skipcopy)
1414                                         *page = bio_page;
1415                                 else
1416                                         tx = async_memcpy(*page, bio_page, page_offset + poff,
1417                                                   b_offset, clen, &submit);
1418                         } else
1419                                 tx = async_memcpy(bio_page, *page, b_offset,
1420                                                   page_offset + poff, clen, &submit);
1421                 }
1422                 /* chain the operations */
1423                 submit.depend_tx = tx;
1424
1425                 if (clen < len) /* hit end of page */
1426                         break;
1427                 page_offset +=  len;
1428         }
1429
1430         return tx;
1431 }
1432
1433 static void ops_complete_biofill(void *stripe_head_ref)
1434 {
1435         struct stripe_head *sh = stripe_head_ref;
1436         int i;
1437         struct r5conf *conf = sh->raid_conf;
1438
1439         pr_debug("%s: stripe %llu\n", __func__,
1440                 (unsigned long long)sh->sector);
1441
1442         /* clear completed biofills */
1443         for (i = sh->disks; i--; ) {
1444                 struct r5dev *dev = &sh->dev[i];
1445
1446                 /* acknowledge completion of a biofill operation */
1447                 /* and check if we need to reply to a read request,
1448                  * new R5_Wantfill requests are held off until
1449                  * !STRIPE_BIOFILL_RUN
1450                  */
1451                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1452                         struct bio *rbi, *rbi2;
1453
1454                         BUG_ON(!dev->read);
1455                         rbi = dev->read;
1456                         dev->read = NULL;
1457                         while (rbi && rbi->bi_iter.bi_sector <
1458                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1459                                 rbi2 = r5_next_bio(conf, rbi, dev->sector);
1460                                 bio_endio(rbi);
1461                                 rbi = rbi2;
1462                         }
1463                 }
1464         }
1465         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1466
1467         set_bit(STRIPE_HANDLE, &sh->state);
1468         raid5_release_stripe(sh);
1469 }
1470
1471 static void ops_run_biofill(struct stripe_head *sh)
1472 {
1473         struct dma_async_tx_descriptor *tx = NULL;
1474         struct async_submit_ctl submit;
1475         int i;
1476         struct r5conf *conf = sh->raid_conf;
1477
1478         BUG_ON(sh->batch_head);
1479         pr_debug("%s: stripe %llu\n", __func__,
1480                 (unsigned long long)sh->sector);
1481
1482         for (i = sh->disks; i--; ) {
1483                 struct r5dev *dev = &sh->dev[i];
1484                 if (test_bit(R5_Wantfill, &dev->flags)) {
1485                         struct bio *rbi;
1486                         spin_lock_irq(&sh->stripe_lock);
1487                         dev->read = rbi = dev->toread;
1488                         dev->toread = NULL;
1489                         spin_unlock_irq(&sh->stripe_lock);
1490                         while (rbi && rbi->bi_iter.bi_sector <
1491                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1492                                 tx = async_copy_data(0, rbi, &dev->page,
1493                                                      dev->offset,
1494                                                      dev->sector, tx, sh, 0);
1495                                 rbi = r5_next_bio(conf, rbi, dev->sector);
1496                         }
1497                 }
1498         }
1499
1500         atomic_inc(&sh->count);
1501         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1502         async_trigger_callback(&submit);
1503 }
1504
1505 static void mark_target_uptodate(struct stripe_head *sh, int target)
1506 {
1507         struct r5dev *tgt;
1508
1509         if (target < 0)
1510                 return;
1511
1512         tgt = &sh->dev[target];
1513         set_bit(R5_UPTODATE, &tgt->flags);
1514         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1515         clear_bit(R5_Wantcompute, &tgt->flags);
1516 }
1517
1518 static void ops_complete_compute(void *stripe_head_ref)
1519 {
1520         struct stripe_head *sh = stripe_head_ref;
1521
1522         pr_debug("%s: stripe %llu\n", __func__,
1523                 (unsigned long long)sh->sector);
1524
1525         /* mark the computed target(s) as uptodate */
1526         mark_target_uptodate(sh, sh->ops.target);
1527         mark_target_uptodate(sh, sh->ops.target2);
1528
1529         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1530         if (sh->check_state == check_state_compute_run)
1531                 sh->check_state = check_state_compute_result;
1532         set_bit(STRIPE_HANDLE, &sh->state);
1533         raid5_release_stripe(sh);
1534 }
1535
1536 /* return a pointer to the address conversion region of the scribble buffer */
1537 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1538 {
1539         return percpu->scribble + i * percpu->scribble_obj_size;
1540 }
1541
1542 /* return a pointer to the address conversion region of the scribble buffer */
1543 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1544                                  struct raid5_percpu *percpu, int i)
1545 {
1546         return (void *) (to_addr_page(percpu, i) + sh->disks + 2);
1547 }
1548
1549 /*
1550  * Return a pointer to record offset address.
1551  */
1552 static unsigned int *
1553 to_addr_offs(struct stripe_head *sh, struct raid5_percpu *percpu)
1554 {
1555         return (unsigned int *) (to_addr_conv(sh, percpu, 0) + sh->disks + 2);
1556 }
1557
1558 static struct dma_async_tx_descriptor *
1559 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1560 {
1561         int disks = sh->disks;
1562         struct page **xor_srcs = to_addr_page(percpu, 0);
1563         unsigned int *off_srcs = to_addr_offs(sh, percpu);
1564         int target = sh->ops.target;
1565         struct r5dev *tgt = &sh->dev[target];
1566         struct page *xor_dest = tgt->page;
1567         unsigned int off_dest = tgt->offset;
1568         int count = 0;
1569         struct dma_async_tx_descriptor *tx;
1570         struct async_submit_ctl submit;
1571         int i;
1572
1573         BUG_ON(sh->batch_head);
1574
1575         pr_debug("%s: stripe %llu block: %d\n",
1576                 __func__, (unsigned long long)sh->sector, target);
1577         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1578
1579         for (i = disks; i--; ) {
1580                 if (i != target) {
1581                         off_srcs[count] = sh->dev[i].offset;
1582                         xor_srcs[count++] = sh->dev[i].page;
1583                 }
1584         }
1585
1586         atomic_inc(&sh->count);
1587
1588         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1589                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1590         if (unlikely(count == 1))
1591                 tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
1592                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1593         else
1594                 tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1595                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1596
1597         return tx;
1598 }
1599
1600 /* set_syndrome_sources - populate source buffers for gen_syndrome
1601  * @srcs - (struct page *) array of size sh->disks
1602  * @offs - (unsigned int) array of offset for each page
1603  * @sh - stripe_head to parse
1604  *
1605  * Populates srcs in proper layout order for the stripe and returns the
1606  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1607  * destination buffer is recorded in srcs[count] and the Q destination
1608  * is recorded in srcs[count+1]].
1609  */
1610 static int set_syndrome_sources(struct page **srcs,
1611                                 unsigned int *offs,
1612                                 struct stripe_head *sh,
1613                                 int srctype)
1614 {
1615         int disks = sh->disks;
1616         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1617         int d0_idx = raid6_d0(sh);
1618         int count;
1619         int i;
1620
1621         for (i = 0; i < disks; i++)
1622                 srcs[i] = NULL;
1623
1624         count = 0;
1625         i = d0_idx;
1626         do {
1627                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1628                 struct r5dev *dev = &sh->dev[i];
1629
1630                 if (i == sh->qd_idx || i == sh->pd_idx ||
1631                     (srctype == SYNDROME_SRC_ALL) ||
1632                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1633                      (test_bit(R5_Wantdrain, &dev->flags) ||
1634                       test_bit(R5_InJournal, &dev->flags))) ||
1635                     (srctype == SYNDROME_SRC_WRITTEN &&
1636                      (dev->written ||
1637                       test_bit(R5_InJournal, &dev->flags)))) {
1638                         if (test_bit(R5_InJournal, &dev->flags))
1639                                 srcs[slot] = sh->dev[i].orig_page;
1640                         else
1641                                 srcs[slot] = sh->dev[i].page;
1642                         /*
1643                          * For R5_InJournal, PAGE_SIZE must be 4KB and will
1644                          * not shared page. In that case, dev[i].offset
1645                          * is 0.
1646                          */
1647                         offs[slot] = sh->dev[i].offset;
1648                 }
1649                 i = raid6_next_disk(i, disks);
1650         } while (i != d0_idx);
1651
1652         return syndrome_disks;
1653 }
1654
1655 static struct dma_async_tx_descriptor *
1656 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1657 {
1658         int disks = sh->disks;
1659         struct page **blocks = to_addr_page(percpu, 0);
1660         unsigned int *offs = to_addr_offs(sh, percpu);
1661         int target;
1662         int qd_idx = sh->qd_idx;
1663         struct dma_async_tx_descriptor *tx;
1664         struct async_submit_ctl submit;
1665         struct r5dev *tgt;
1666         struct page *dest;
1667         unsigned int dest_off;
1668         int i;
1669         int count;
1670
1671         BUG_ON(sh->batch_head);
1672         if (sh->ops.target < 0)
1673                 target = sh->ops.target2;
1674         else if (sh->ops.target2 < 0)
1675                 target = sh->ops.target;
1676         else
1677                 /* we should only have one valid target */
1678                 BUG();
1679         BUG_ON(target < 0);
1680         pr_debug("%s: stripe %llu block: %d\n",
1681                 __func__, (unsigned long long)sh->sector, target);
1682
1683         tgt = &sh->dev[target];
1684         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1685         dest = tgt->page;
1686         dest_off = tgt->offset;
1687
1688         atomic_inc(&sh->count);
1689
1690         if (target == qd_idx) {
1691                 count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1692                 blocks[count] = NULL; /* regenerating p is not necessary */
1693                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1694                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1695                                   ops_complete_compute, sh,
1696                                   to_addr_conv(sh, percpu, 0));
1697                 tx = async_gen_syndrome(blocks, offs, count+2,
1698                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1699         } else {
1700                 /* Compute any data- or p-drive using XOR */
1701                 count = 0;
1702                 for (i = disks; i-- ; ) {
1703                         if (i == target || i == qd_idx)
1704                                 continue;
1705                         offs[count] = sh->dev[i].offset;
1706                         blocks[count++] = sh->dev[i].page;
1707                 }
1708
1709                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1710                                   NULL, ops_complete_compute, sh,
1711                                   to_addr_conv(sh, percpu, 0));
1712                 tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1713                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1714         }
1715
1716         return tx;
1717 }
1718
1719 static struct dma_async_tx_descriptor *
1720 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1721 {
1722         int i, count, disks = sh->disks;
1723         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1724         int d0_idx = raid6_d0(sh);
1725         int faila = -1, failb = -1;
1726         int target = sh->ops.target;
1727         int target2 = sh->ops.target2;
1728         struct r5dev *tgt = &sh->dev[target];
1729         struct r5dev *tgt2 = &sh->dev[target2];
1730         struct dma_async_tx_descriptor *tx;
1731         struct page **blocks = to_addr_page(percpu, 0);
1732         unsigned int *offs = to_addr_offs(sh, percpu);
1733         struct async_submit_ctl submit;
1734
1735         BUG_ON(sh->batch_head);
1736         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1737                  __func__, (unsigned long long)sh->sector, target, target2);
1738         BUG_ON(target < 0 || target2 < 0);
1739         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1740         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1741
1742         /* we need to open-code set_syndrome_sources to handle the
1743          * slot number conversion for 'faila' and 'failb'
1744          */
1745         for (i = 0; i < disks ; i++) {
1746                 offs[i] = 0;
1747                 blocks[i] = NULL;
1748         }
1749         count = 0;
1750         i = d0_idx;
1751         do {
1752                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1753
1754                 offs[slot] = sh->dev[i].offset;
1755                 blocks[slot] = sh->dev[i].page;
1756
1757                 if (i == target)
1758                         faila = slot;
1759                 if (i == target2)
1760                         failb = slot;
1761                 i = raid6_next_disk(i, disks);
1762         } while (i != d0_idx);
1763
1764         BUG_ON(faila == failb);
1765         if (failb < faila)
1766                 swap(faila, failb);
1767         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1768                  __func__, (unsigned long long)sh->sector, faila, failb);
1769
1770         atomic_inc(&sh->count);
1771
1772         if (failb == syndrome_disks+1) {
1773                 /* Q disk is one of the missing disks */
1774                 if (faila == syndrome_disks) {
1775                         /* Missing P+Q, just recompute */
1776                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1777                                           ops_complete_compute, sh,
1778                                           to_addr_conv(sh, percpu, 0));
1779                         return async_gen_syndrome(blocks, offs, syndrome_disks+2,
1780                                                   RAID5_STRIPE_SIZE(sh->raid_conf),
1781                                                   &submit);
1782                 } else {
1783                         struct page *dest;
1784                         unsigned int dest_off;
1785                         int data_target;
1786                         int qd_idx = sh->qd_idx;
1787
1788                         /* Missing D+Q: recompute D from P, then recompute Q */
1789                         if (target == qd_idx)
1790                                 data_target = target2;
1791                         else
1792                                 data_target = target;
1793
1794                         count = 0;
1795                         for (i = disks; i-- ; ) {
1796                                 if (i == data_target || i == qd_idx)
1797                                         continue;
1798                                 offs[count] = sh->dev[i].offset;
1799                                 blocks[count++] = sh->dev[i].page;
1800                         }
1801                         dest = sh->dev[data_target].page;
1802                         dest_off = sh->dev[data_target].offset;
1803                         init_async_submit(&submit,
1804                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1805                                           NULL, NULL, NULL,
1806                                           to_addr_conv(sh, percpu, 0));
1807                         tx = async_xor_offs(dest, dest_off, blocks, offs, count,
1808                                        RAID5_STRIPE_SIZE(sh->raid_conf),
1809                                        &submit);
1810
1811                         count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_ALL);
1812                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1813                                           ops_complete_compute, sh,
1814                                           to_addr_conv(sh, percpu, 0));
1815                         return async_gen_syndrome(blocks, offs, count+2,
1816                                                   RAID5_STRIPE_SIZE(sh->raid_conf),
1817                                                   &submit);
1818                 }
1819         } else {
1820                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1821                                   ops_complete_compute, sh,
1822                                   to_addr_conv(sh, percpu, 0));
1823                 if (failb == syndrome_disks) {
1824                         /* We're missing D+P. */
1825                         return async_raid6_datap_recov(syndrome_disks+2,
1826                                                 RAID5_STRIPE_SIZE(sh->raid_conf),
1827                                                 faila,
1828                                                 blocks, offs, &submit);
1829                 } else {
1830                         /* We're missing D+D. */
1831                         return async_raid6_2data_recov(syndrome_disks+2,
1832                                                 RAID5_STRIPE_SIZE(sh->raid_conf),
1833                                                 faila, failb,
1834                                                 blocks, offs, &submit);
1835                 }
1836         }
1837 }
1838
1839 static void ops_complete_prexor(void *stripe_head_ref)
1840 {
1841         struct stripe_head *sh = stripe_head_ref;
1842
1843         pr_debug("%s: stripe %llu\n", __func__,
1844                 (unsigned long long)sh->sector);
1845
1846         if (r5c_is_writeback(sh->raid_conf->log))
1847                 /*
1848                  * raid5-cache write back uses orig_page during prexor.
1849                  * After prexor, it is time to free orig_page
1850                  */
1851                 r5c_release_extra_page(sh);
1852 }
1853
1854 static struct dma_async_tx_descriptor *
1855 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1856                 struct dma_async_tx_descriptor *tx)
1857 {
1858         int disks = sh->disks;
1859         struct page **xor_srcs = to_addr_page(percpu, 0);
1860         unsigned int *off_srcs = to_addr_offs(sh, percpu);
1861         int count = 0, pd_idx = sh->pd_idx, i;
1862         struct async_submit_ctl submit;
1863
1864         /* existing parity data subtracted */
1865         unsigned int off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
1866         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1867
1868         BUG_ON(sh->batch_head);
1869         pr_debug("%s: stripe %llu\n", __func__,
1870                 (unsigned long long)sh->sector);
1871
1872         for (i = disks; i--; ) {
1873                 struct r5dev *dev = &sh->dev[i];
1874                 /* Only process blocks that are known to be uptodate */
1875                 if (test_bit(R5_InJournal, &dev->flags)) {
1876                         /*
1877                          * For this case, PAGE_SIZE must be equal to 4KB and
1878                          * page offset is zero.
1879                          */
1880                         off_srcs[count] = dev->offset;
1881                         xor_srcs[count++] = dev->orig_page;
1882                 } else if (test_bit(R5_Wantdrain, &dev->flags)) {
1883                         off_srcs[count] = dev->offset;
1884                         xor_srcs[count++] = dev->page;
1885                 }
1886         }
1887
1888         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1889                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1890         tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
1891                         RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1892
1893         return tx;
1894 }
1895
1896 static struct dma_async_tx_descriptor *
1897 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1898                 struct dma_async_tx_descriptor *tx)
1899 {
1900         struct page **blocks = to_addr_page(percpu, 0);
1901         unsigned int *offs = to_addr_offs(sh, percpu);
1902         int count;
1903         struct async_submit_ctl submit;
1904
1905         pr_debug("%s: stripe %llu\n", __func__,
1906                 (unsigned long long)sh->sector);
1907
1908         count = set_syndrome_sources(blocks, offs, sh, SYNDROME_SRC_WANT_DRAIN);
1909
1910         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1911                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1912         tx = async_gen_syndrome(blocks, offs, count+2,
1913                         RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
1914
1915         return tx;
1916 }
1917
1918 static struct dma_async_tx_descriptor *
1919 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1920 {
1921         struct r5conf *conf = sh->raid_conf;
1922         int disks = sh->disks;
1923         int i;
1924         struct stripe_head *head_sh = sh;
1925
1926         pr_debug("%s: stripe %llu\n", __func__,
1927                 (unsigned long long)sh->sector);
1928
1929         for (i = disks; i--; ) {
1930                 struct r5dev *dev;
1931                 struct bio *chosen;
1932
1933                 sh = head_sh;
1934                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1935                         struct bio *wbi;
1936
1937 again:
1938                         dev = &sh->dev[i];
1939                         /*
1940                          * clear R5_InJournal, so when rewriting a page in
1941                          * journal, it is not skipped by r5l_log_stripe()
1942                          */
1943                         clear_bit(R5_InJournal, &dev->flags);
1944                         spin_lock_irq(&sh->stripe_lock);
1945                         chosen = dev->towrite;
1946                         dev->towrite = NULL;
1947                         sh->overwrite_disks = 0;
1948                         BUG_ON(dev->written);
1949                         wbi = dev->written = chosen;
1950                         spin_unlock_irq(&sh->stripe_lock);
1951                         WARN_ON(dev->page != dev->orig_page);
1952
1953                         while (wbi && wbi->bi_iter.bi_sector <
1954                                 dev->sector + RAID5_STRIPE_SECTORS(conf)) {
1955                                 if (wbi->bi_opf & REQ_FUA)
1956                                         set_bit(R5_WantFUA, &dev->flags);
1957                                 if (wbi->bi_opf & REQ_SYNC)
1958                                         set_bit(R5_SyncIO, &dev->flags);
1959                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1960                                         set_bit(R5_Discard, &dev->flags);
1961                                 else {
1962                                         tx = async_copy_data(1, wbi, &dev->page,
1963                                                              dev->offset,
1964                                                              dev->sector, tx, sh,
1965                                                              r5c_is_writeback(conf->log));
1966                                         if (dev->page != dev->orig_page &&
1967                                             !r5c_is_writeback(conf->log)) {
1968                                                 set_bit(R5_SkipCopy, &dev->flags);
1969                                                 clear_bit(R5_UPTODATE, &dev->flags);
1970                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1971                                         }
1972                                 }
1973                                 wbi = r5_next_bio(conf, wbi, dev->sector);
1974                         }
1975
1976                         if (head_sh->batch_head) {
1977                                 sh = list_first_entry(&sh->batch_list,
1978                                                       struct stripe_head,
1979                                                       batch_list);
1980                                 if (sh == head_sh)
1981                                         continue;
1982                                 goto again;
1983                         }
1984                 }
1985         }
1986
1987         return tx;
1988 }
1989
1990 static void ops_complete_reconstruct(void *stripe_head_ref)
1991 {
1992         struct stripe_head *sh = stripe_head_ref;
1993         int disks = sh->disks;
1994         int pd_idx = sh->pd_idx;
1995         int qd_idx = sh->qd_idx;
1996         int i;
1997         bool fua = false, sync = false, discard = false;
1998
1999         pr_debug("%s: stripe %llu\n", __func__,
2000                 (unsigned long long)sh->sector);
2001
2002         for (i = disks; i--; ) {
2003                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
2004                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
2005                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
2006         }
2007
2008         for (i = disks; i--; ) {
2009                 struct r5dev *dev = &sh->dev[i];
2010
2011                 if (dev->written || i == pd_idx || i == qd_idx) {
2012                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
2013                                 set_bit(R5_UPTODATE, &dev->flags);
2014                                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
2015                                         set_bit(R5_Expanded, &dev->flags);
2016                         }
2017                         if (fua)
2018                                 set_bit(R5_WantFUA, &dev->flags);
2019                         if (sync)
2020                                 set_bit(R5_SyncIO, &dev->flags);
2021                 }
2022         }
2023
2024         if (sh->reconstruct_state == reconstruct_state_drain_run)
2025                 sh->reconstruct_state = reconstruct_state_drain_result;
2026         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
2027                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
2028         else {
2029                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
2030                 sh->reconstruct_state = reconstruct_state_result;
2031         }
2032
2033         set_bit(STRIPE_HANDLE, &sh->state);
2034         raid5_release_stripe(sh);
2035 }
2036
2037 static void
2038 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
2039                      struct dma_async_tx_descriptor *tx)
2040 {
2041         int disks = sh->disks;
2042         struct page **xor_srcs;
2043         unsigned int *off_srcs;
2044         struct async_submit_ctl submit;
2045         int count, pd_idx = sh->pd_idx, i;
2046         struct page *xor_dest;
2047         unsigned int off_dest;
2048         int prexor = 0;
2049         unsigned long flags;
2050         int j = 0;
2051         struct stripe_head *head_sh = sh;
2052         int last_stripe;
2053
2054         pr_debug("%s: stripe %llu\n", __func__,
2055                 (unsigned long long)sh->sector);
2056
2057         for (i = 0; i < sh->disks; i++) {
2058                 if (pd_idx == i)
2059                         continue;
2060                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
2061                         break;
2062         }
2063         if (i >= sh->disks) {
2064                 atomic_inc(&sh->count);
2065                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
2066                 ops_complete_reconstruct(sh);
2067                 return;
2068         }
2069 again:
2070         count = 0;
2071         xor_srcs = to_addr_page(percpu, j);
2072         off_srcs = to_addr_offs(sh, percpu);
2073         /* check if prexor is active which means only process blocks
2074          * that are part of a read-modify-write (written)
2075          */
2076         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2077                 prexor = 1;
2078                 off_dest = off_srcs[count] = sh->dev[pd_idx].offset;
2079                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
2080                 for (i = disks; i--; ) {
2081                         struct r5dev *dev = &sh->dev[i];
2082                         if (head_sh->dev[i].written ||
2083                             test_bit(R5_InJournal, &head_sh->dev[i].flags)) {
2084                                 off_srcs[count] = dev->offset;
2085                                 xor_srcs[count++] = dev->page;
2086                         }
2087                 }
2088         } else {
2089                 xor_dest = sh->dev[pd_idx].page;
2090                 off_dest = sh->dev[pd_idx].offset;
2091                 for (i = disks; i--; ) {
2092                         struct r5dev *dev = &sh->dev[i];
2093                         if (i != pd_idx) {
2094                                 off_srcs[count] = dev->offset;
2095                                 xor_srcs[count++] = dev->page;
2096                         }
2097                 }
2098         }
2099
2100         /* 1/ if we prexor'd then the dest is reused as a source
2101          * 2/ if we did not prexor then we are redoing the parity
2102          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
2103          * for the synchronous xor case
2104          */
2105         last_stripe = !head_sh->batch_head ||
2106                 list_first_entry(&sh->batch_list,
2107                                  struct stripe_head, batch_list) == head_sh;
2108         if (last_stripe) {
2109                 flags = ASYNC_TX_ACK |
2110                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
2111
2112                 atomic_inc(&head_sh->count);
2113                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
2114                                   to_addr_conv(sh, percpu, j));
2115         } else {
2116                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
2117                 init_async_submit(&submit, flags, tx, NULL, NULL,
2118                                   to_addr_conv(sh, percpu, j));
2119         }
2120
2121         if (unlikely(count == 1))
2122                 tx = async_memcpy(xor_dest, xor_srcs[0], off_dest, off_srcs[0],
2123                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2124         else
2125                 tx = async_xor_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2126                                 RAID5_STRIPE_SIZE(sh->raid_conf), &submit);
2127         if (!last_stripe) {
2128                 j++;
2129                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
2130                                       batch_list);
2131                 goto again;
2132         }
2133 }
2134
2135 static void
2136 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
2137                      struct dma_async_tx_descriptor *tx)
2138 {
2139         struct async_submit_ctl submit;
2140         struct page **blocks;
2141         unsigned int *offs;
2142         int count, i, j = 0;
2143         struct stripe_head *head_sh = sh;
2144         int last_stripe;
2145         int synflags;
2146         unsigned long txflags;
2147
2148         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
2149
2150         for (i = 0; i < sh->disks; i++) {
2151                 if (sh->pd_idx == i || sh->qd_idx == i)
2152                         continue;
2153                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
2154                         break;
2155         }
2156         if (i >= sh->disks) {
2157                 atomic_inc(&sh->count);
2158                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
2159                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
2160                 ops_complete_reconstruct(sh);
2161                 return;
2162         }
2163
2164 again:
2165         blocks = to_addr_page(percpu, j);
2166         offs = to_addr_offs(sh, percpu);
2167
2168         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
2169                 synflags = SYNDROME_SRC_WRITTEN;
2170                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
2171         } else {
2172                 synflags = SYNDROME_SRC_ALL;
2173                 txflags = ASYNC_TX_ACK;
2174         }
2175
2176         count = set_syndrome_sources(blocks, offs, sh, synflags);
2177         last_stripe = !head_sh->batch_head ||
2178                 list_first_entry(&sh->batch_list,
2179                                  struct stripe_head, batch_list) == head_sh;
2180
2181         if (last_stripe) {
2182                 atomic_inc(&head_sh->count);
2183                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
2184                                   head_sh, to_addr_conv(sh, percpu, j));
2185         } else
2186                 init_async_submit(&submit, 0, tx, NULL, NULL,
2187                                   to_addr_conv(sh, percpu, j));
2188         tx = async_gen_syndrome(blocks, offs, count+2,
2189                         RAID5_STRIPE_SIZE(sh->raid_conf),  &submit);
2190         if (!last_stripe) {
2191                 j++;
2192                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
2193                                       batch_list);
2194                 goto again;
2195         }
2196 }
2197
2198 static void ops_complete_check(void *stripe_head_ref)
2199 {
2200         struct stripe_head *sh = stripe_head_ref;
2201
2202         pr_debug("%s: stripe %llu\n", __func__,
2203                 (unsigned long long)sh->sector);
2204
2205         sh->check_state = check_state_check_result;
2206         set_bit(STRIPE_HANDLE, &sh->state);
2207         raid5_release_stripe(sh);
2208 }
2209
2210 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2211 {
2212         int disks = sh->disks;
2213         int pd_idx = sh->pd_idx;
2214         int qd_idx = sh->qd_idx;
2215         struct page *xor_dest;
2216         unsigned int off_dest;
2217         struct page **xor_srcs = to_addr_page(percpu, 0);
2218         unsigned int *off_srcs = to_addr_offs(sh, percpu);
2219         struct dma_async_tx_descriptor *tx;
2220         struct async_submit_ctl submit;
2221         int count;
2222         int i;
2223
2224         pr_debug("%s: stripe %llu\n", __func__,
2225                 (unsigned long long)sh->sector);
2226
2227         BUG_ON(sh->batch_head);
2228         count = 0;
2229         xor_dest = sh->dev[pd_idx].page;
2230         off_dest = sh->dev[pd_idx].offset;
2231         off_srcs[count] = off_dest;
2232         xor_srcs[count++] = xor_dest;
2233         for (i = disks; i--; ) {
2234                 if (i == pd_idx || i == qd_idx)
2235                         continue;
2236                 off_srcs[count] = sh->dev[i].offset;
2237                 xor_srcs[count++] = sh->dev[i].page;
2238         }
2239
2240         init_async_submit(&submit, 0, NULL, NULL, NULL,
2241                           to_addr_conv(sh, percpu, 0));
2242         tx = async_xor_val_offs(xor_dest, off_dest, xor_srcs, off_srcs, count,
2243                            RAID5_STRIPE_SIZE(sh->raid_conf),
2244                            &sh->ops.zero_sum_result, &submit);
2245
2246         atomic_inc(&sh->count);
2247         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2248         tx = async_trigger_callback(&submit);
2249 }
2250
2251 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2252 {
2253         struct page **srcs = to_addr_page(percpu, 0);
2254         unsigned int *offs = to_addr_offs(sh, percpu);
2255         struct async_submit_ctl submit;
2256         int count;
2257
2258         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2259                 (unsigned long long)sh->sector, checkp);
2260
2261         BUG_ON(sh->batch_head);
2262         count = set_syndrome_sources(srcs, offs, sh, SYNDROME_SRC_ALL);
2263         if (!checkp)
2264                 srcs[count] = NULL;
2265
2266         atomic_inc(&sh->count);
2267         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2268                           sh, to_addr_conv(sh, percpu, 0));
2269         async_syndrome_val(srcs, offs, count+2,
2270                            RAID5_STRIPE_SIZE(sh->raid_conf),
2271                            &sh->ops.zero_sum_result, percpu->spare_page, 0, &submit);
2272 }
2273
2274 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2275 {
2276         int overlap_clear = 0, i, disks = sh->disks;
2277         struct dma_async_tx_descriptor *tx = NULL;
2278         struct r5conf *conf = sh->raid_conf;
2279         int level = conf->level;
2280         struct raid5_percpu *percpu;
2281
2282         local_lock(&conf->percpu->lock);
2283         percpu = this_cpu_ptr(conf->percpu);
2284         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2285                 ops_run_biofill(sh);
2286                 overlap_clear++;
2287         }
2288
2289         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2290                 if (level < 6)
2291                         tx = ops_run_compute5(sh, percpu);
2292                 else {
2293                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2294                                 tx = ops_run_compute6_1(sh, percpu);
2295                         else
2296                                 tx = ops_run_compute6_2(sh, percpu);
2297                 }
2298                 /* terminate the chain if reconstruct is not set to be run */
2299                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2300                         async_tx_ack(tx);
2301         }
2302
2303         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2304                 if (level < 6)
2305                         tx = ops_run_prexor5(sh, percpu, tx);
2306                 else
2307                         tx = ops_run_prexor6(sh, percpu, tx);
2308         }
2309
2310         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2311                 tx = ops_run_partial_parity(sh, percpu, tx);
2312
2313         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2314                 tx = ops_run_biodrain(sh, tx);
2315                 overlap_clear++;
2316         }
2317
2318         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2319                 if (level < 6)
2320                         ops_run_reconstruct5(sh, percpu, tx);
2321                 else
2322                         ops_run_reconstruct6(sh, percpu, tx);
2323         }
2324
2325         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2326                 if (sh->check_state == check_state_run)
2327                         ops_run_check_p(sh, percpu);
2328                 else if (sh->check_state == check_state_run_q)
2329                         ops_run_check_pq(sh, percpu, 0);
2330                 else if (sh->check_state == check_state_run_pq)
2331                         ops_run_check_pq(sh, percpu, 1);
2332                 else
2333                         BUG();
2334         }
2335
2336         if (overlap_clear && !sh->batch_head) {
2337                 for (i = disks; i--; ) {
2338                         struct r5dev *dev = &sh->dev[i];
2339                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2340                                 wake_up_bit(&dev->flags, R5_Overlap);
2341                 }
2342         }
2343         local_unlock(&conf->percpu->lock);
2344 }
2345
2346 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2347 {
2348 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2349         kfree(sh->pages);
2350 #endif
2351         if (sh->ppl_page)
2352                 __free_page(sh->ppl_page);
2353         kmem_cache_free(sc, sh);
2354 }
2355
2356 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2357         int disks, struct r5conf *conf)
2358 {
2359         struct stripe_head *sh;
2360
2361         sh = kmem_cache_zalloc(sc, gfp);
2362         if (sh) {
2363                 spin_lock_init(&sh->stripe_lock);
2364                 spin_lock_init(&sh->batch_lock);
2365                 INIT_LIST_HEAD(&sh->batch_list);
2366                 INIT_LIST_HEAD(&sh->lru);
2367                 INIT_LIST_HEAD(&sh->r5c);
2368                 INIT_LIST_HEAD(&sh->log_list);
2369                 atomic_set(&sh->count, 1);
2370                 sh->raid_conf = conf;
2371                 sh->log_start = MaxSector;
2372
2373                 if (raid5_has_ppl(conf)) {
2374                         sh->ppl_page = alloc_page(gfp);
2375                         if (!sh->ppl_page) {
2376                                 free_stripe(sc, sh);
2377                                 return NULL;
2378                         }
2379                 }
2380 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2381                 if (init_stripe_shared_pages(sh, conf, disks)) {
2382                         free_stripe(sc, sh);
2383                         return NULL;
2384                 }
2385 #endif
2386         }
2387         return sh;
2388 }
2389 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2390 {
2391         struct stripe_head *sh;
2392
2393         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2394         if (!sh)
2395                 return 0;
2396
2397         if (grow_buffers(sh, gfp)) {
2398                 shrink_buffers(sh);
2399                 free_stripe(conf->slab_cache, sh);
2400                 return 0;
2401         }
2402         sh->hash_lock_index =
2403                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2404         /* we just created an active stripe so... */
2405         atomic_inc(&conf->active_stripes);
2406
2407         raid5_release_stripe(sh);
2408         WRITE_ONCE(conf->max_nr_stripes, conf->max_nr_stripes + 1);
2409         return 1;
2410 }
2411
2412 static int grow_stripes(struct r5conf *conf, int num)
2413 {
2414         struct kmem_cache *sc;
2415         size_t namelen = sizeof(conf->cache_name[0]);
2416         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2417
2418         if (mddev_is_dm(conf->mddev))
2419                 snprintf(conf->cache_name[0], namelen,
2420                         "raid%d-%p", conf->level, conf->mddev);
2421         else
2422                 snprintf(conf->cache_name[0], namelen,
2423                         "raid%d-%s", conf->level, mdname(conf->mddev));
2424         snprintf(conf->cache_name[1], namelen, "%.27s-alt", conf->cache_name[0]);
2425
2426         conf->active_name = 0;
2427         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2428                                struct_size_t(struct stripe_head, dev, devs),
2429                                0, 0, NULL);
2430         if (!sc)
2431                 return 1;
2432         conf->slab_cache = sc;
2433         conf->pool_size = devs;
2434         while (num--)
2435                 if (!grow_one_stripe(conf, GFP_KERNEL))
2436                         return 1;
2437
2438         return 0;
2439 }
2440
2441 /**
2442  * scribble_alloc - allocate percpu scribble buffer for required size
2443  *                  of the scribble region
2444  * @percpu: from for_each_present_cpu() of the caller
2445  * @num: total number of disks in the array
2446  * @cnt: scribble objs count for required size of the scribble region
2447  *
2448  * The scribble buffer size must be enough to contain:
2449  * 1/ a struct page pointer for each device in the array +2
2450  * 2/ room to convert each entry in (1) to its corresponding dma
2451  *    (dma_map_page()) or page (page_address()) address.
2452  *
2453  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2454  * calculate over all devices (not just the data blocks), using zeros in place
2455  * of the P and Q blocks.
2456  */
2457 static int scribble_alloc(struct raid5_percpu *percpu,
2458                           int num, int cnt)
2459 {
2460         size_t obj_size =
2461                 sizeof(struct page *) * (num + 2) +
2462                 sizeof(addr_conv_t) * (num + 2) +
2463                 sizeof(unsigned int) * (num + 2);
2464         void *scribble;
2465
2466         /*
2467          * If here is in raid array suspend context, it is in memalloc noio
2468          * context as well, there is no potential recursive memory reclaim
2469          * I/Os with the GFP_KERNEL flag.
2470          */
2471         scribble = kvmalloc_array(cnt, obj_size, GFP_KERNEL);
2472         if (!scribble)
2473                 return -ENOMEM;
2474
2475         kvfree(percpu->scribble);
2476
2477         percpu->scribble = scribble;
2478         percpu->scribble_obj_size = obj_size;
2479         return 0;
2480 }
2481
2482 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2483 {
2484         unsigned long cpu;
2485         int err = 0;
2486
2487         /* Never shrink. */
2488         if (conf->scribble_disks >= new_disks &&
2489             conf->scribble_sectors >= new_sectors)
2490                 return 0;
2491
2492         raid5_quiesce(conf->mddev, true);
2493         cpus_read_lock();
2494
2495         for_each_present_cpu(cpu) {
2496                 struct raid5_percpu *percpu;
2497
2498                 percpu = per_cpu_ptr(conf->percpu, cpu);
2499                 err = scribble_alloc(percpu, new_disks,
2500                                      new_sectors / RAID5_STRIPE_SECTORS(conf));
2501                 if (err)
2502                         break;
2503         }
2504
2505         cpus_read_unlock();
2506         raid5_quiesce(conf->mddev, false);
2507
2508         if (!err) {
2509                 conf->scribble_disks = new_disks;
2510                 conf->scribble_sectors = new_sectors;
2511         }
2512         return err;
2513 }
2514
2515 static int resize_stripes(struct r5conf *conf, int newsize)
2516 {
2517         /* Make all the stripes able to hold 'newsize' devices.
2518          * New slots in each stripe get 'page' set to a new page.
2519          *
2520          * This happens in stages:
2521          * 1/ create a new kmem_cache and allocate the required number of
2522          *    stripe_heads.
2523          * 2/ gather all the old stripe_heads and transfer the pages across
2524          *    to the new stripe_heads.  This will have the side effect of
2525          *    freezing the array as once all stripe_heads have been collected,
2526          *    no IO will be possible.  Old stripe heads are freed once their
2527          *    pages have been transferred over, and the old kmem_cache is
2528          *    freed when all stripes are done.
2529          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2530          *    we simple return a failure status - no need to clean anything up.
2531          * 4/ allocate new pages for the new slots in the new stripe_heads.
2532          *    If this fails, we don't bother trying the shrink the
2533          *    stripe_heads down again, we just leave them as they are.
2534          *    As each stripe_head is processed the new one is released into
2535          *    active service.
2536          *
2537          * Once step2 is started, we cannot afford to wait for a write,
2538          * so we use GFP_NOIO allocations.
2539          */
2540         struct stripe_head *osh, *nsh;
2541         LIST_HEAD(newstripes);
2542         struct disk_info *ndisks;
2543         int err = 0;
2544         struct kmem_cache *sc;
2545         int i;
2546         int hash, cnt;
2547
2548         md_allow_write(conf->mddev);
2549
2550         /* Step 1 */
2551         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2552                                struct_size_t(struct stripe_head, dev, newsize),
2553                                0, 0, NULL);
2554         if (!sc)
2555                 return -ENOMEM;
2556
2557         /* Need to ensure auto-resizing doesn't interfere */
2558         mutex_lock(&conf->cache_size_mutex);
2559
2560         for (i = conf->max_nr_stripes; i; i--) {
2561                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2562                 if (!nsh)
2563                         break;
2564
2565                 list_add(&nsh->lru, &newstripes);
2566         }
2567         if (i) {
2568                 /* didn't get enough, give up */
2569                 while (!list_empty(&newstripes)) {
2570                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2571                         list_del(&nsh->lru);
2572                         free_stripe(sc, nsh);
2573                 }
2574                 kmem_cache_destroy(sc);
2575                 mutex_unlock(&conf->cache_size_mutex);
2576                 return -ENOMEM;
2577         }
2578         /* Step 2 - Must use GFP_NOIO now.
2579          * OK, we have enough stripes, start collecting inactive
2580          * stripes and copying them over
2581          */
2582         hash = 0;
2583         cnt = 0;
2584         list_for_each_entry(nsh, &newstripes, lru) {
2585                 lock_device_hash_lock(conf, hash);
2586                 wait_event_cmd(conf->wait_for_stripe,
2587                                     !list_empty(conf->inactive_list + hash),
2588                                     unlock_device_hash_lock(conf, hash),
2589                                     lock_device_hash_lock(conf, hash));
2590                 osh = get_free_stripe(conf, hash);
2591                 unlock_device_hash_lock(conf, hash);
2592
2593 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2594         for (i = 0; i < osh->nr_pages; i++) {
2595                 nsh->pages[i] = osh->pages[i];
2596                 osh->pages[i] = NULL;
2597         }
2598 #endif
2599                 for(i=0; i<conf->pool_size; i++) {
2600                         nsh->dev[i].page = osh->dev[i].page;
2601                         nsh->dev[i].orig_page = osh->dev[i].page;
2602                         nsh->dev[i].offset = osh->dev[i].offset;
2603                 }
2604                 nsh->hash_lock_index = hash;
2605                 free_stripe(conf->slab_cache, osh);
2606                 cnt++;
2607                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2608                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2609                         hash++;
2610                         cnt = 0;
2611                 }
2612         }
2613         kmem_cache_destroy(conf->slab_cache);
2614
2615         /* Step 3.
2616          * At this point, we are holding all the stripes so the array
2617          * is completely stalled, so now is a good time to resize
2618          * conf->disks and the scribble region
2619          */
2620         ndisks = kcalloc(newsize, sizeof(struct disk_info), GFP_NOIO);
2621         if (ndisks) {
2622                 for (i = 0; i < conf->pool_size; i++)
2623                         ndisks[i] = conf->disks[i];
2624
2625                 for (i = conf->pool_size; i < newsize; i++) {
2626                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2627                         if (!ndisks[i].extra_page)
2628                                 err = -ENOMEM;
2629                 }
2630
2631                 if (err) {
2632                         for (i = conf->pool_size; i < newsize; i++)
2633                                 if (ndisks[i].extra_page)
2634                                         put_page(ndisks[i].extra_page);
2635                         kfree(ndisks);
2636                 } else {
2637                         kfree(conf->disks);
2638                         conf->disks = ndisks;
2639                 }
2640         } else
2641                 err = -ENOMEM;
2642
2643         conf->slab_cache = sc;
2644         conf->active_name = 1-conf->active_name;
2645
2646         /* Step 4, return new stripes to service */
2647         while(!list_empty(&newstripes)) {
2648                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2649                 list_del_init(&nsh->lru);
2650
2651 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
2652                 for (i = 0; i < nsh->nr_pages; i++) {
2653                         if (nsh->pages[i])
2654                                 continue;
2655                         nsh->pages[i] = alloc_page(GFP_NOIO);
2656                         if (!nsh->pages[i])
2657                                 err = -ENOMEM;
2658                 }
2659
2660                 for (i = conf->raid_disks; i < newsize; i++) {
2661                         if (nsh->dev[i].page)
2662                                 continue;
2663                         nsh->dev[i].page = raid5_get_dev_page(nsh, i);
2664                         nsh->dev[i].orig_page = nsh->dev[i].page;
2665                         nsh->dev[i].offset = raid5_get_page_offset(nsh, i);
2666                 }
2667 #else
2668                 for (i=conf->raid_disks; i < newsize; i++)
2669                         if (nsh->dev[i].page == NULL) {
2670                                 struct page *p = alloc_page(GFP_NOIO);
2671                                 nsh->dev[i].page = p;
2672                                 nsh->dev[i].orig_page = p;
2673                                 nsh->dev[i].offset = 0;
2674                                 if (!p)
2675                                         err = -ENOMEM;
2676                         }
2677 #endif
2678                 raid5_release_stripe(nsh);
2679         }
2680         /* critical section pass, GFP_NOIO no longer needed */
2681
2682         if (!err)
2683                 conf->pool_size = newsize;
2684         mutex_unlock(&conf->cache_size_mutex);
2685
2686         return err;
2687 }
2688
2689 static int drop_one_stripe(struct r5conf *conf)
2690 {
2691         struct stripe_head *sh;
2692         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2693
2694         spin_lock_irq(conf->hash_locks + hash);
2695         sh = get_free_stripe(conf, hash);
2696         spin_unlock_irq(conf->hash_locks + hash);
2697         if (!sh)
2698                 return 0;
2699         BUG_ON(atomic_read(&sh->count));
2700         shrink_buffers(sh);
2701         free_stripe(conf->slab_cache, sh);
2702         atomic_dec(&conf->active_stripes);
2703         WRITE_ONCE(conf->max_nr_stripes, conf->max_nr_stripes - 1);
2704         return 1;
2705 }
2706
2707 static void shrink_stripes(struct r5conf *conf)
2708 {
2709         while (conf->max_nr_stripes &&
2710                drop_one_stripe(conf))
2711                 ;
2712
2713         kmem_cache_destroy(conf->slab_cache);
2714         conf->slab_cache = NULL;
2715 }
2716
2717 static void raid5_end_read_request(struct bio * bi)
2718 {
2719         struct stripe_head *sh = bi->bi_private;
2720         struct r5conf *conf = sh->raid_conf;
2721         int disks = sh->disks, i;
2722         struct md_rdev *rdev = NULL;
2723         sector_t s;
2724
2725         for (i=0 ; i<disks; i++)
2726                 if (bi == &sh->dev[i].req)
2727                         break;
2728
2729         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2730                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2731                 bi->bi_status);
2732         if (i == disks) {
2733                 BUG();
2734                 return;
2735         }
2736         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2737                 /* If replacement finished while this request was outstanding,
2738                  * 'replacement' might be NULL already.
2739                  * In that case it moved down to 'rdev'.
2740                  * rdev is not removed until all requests are finished.
2741                  */
2742                 rdev = conf->disks[i].replacement;
2743         if (!rdev)
2744                 rdev = conf->disks[i].rdev;
2745
2746         if (use_new_offset(conf, sh))
2747                 s = sh->sector + rdev->new_data_offset;
2748         else
2749                 s = sh->sector + rdev->data_offset;
2750         if (!bi->bi_status) {
2751                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2752                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2753                         /* Note that this cannot happen on a
2754                          * replacement device.  We just fail those on
2755                          * any error
2756                          */
2757                         pr_info_ratelimited(
2758                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %pg)\n",
2759                                 mdname(conf->mddev), RAID5_STRIPE_SECTORS(conf),
2760                                 (unsigned long long)s,
2761                                 rdev->bdev);
2762                         atomic_add(RAID5_STRIPE_SECTORS(conf), &rdev->corrected_errors);
2763                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2764                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2765                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2766                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2767
2768                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2769                         /*
2770                          * end read for a page in journal, this
2771                          * must be preparing for prexor in rmw
2772                          */
2773                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2774
2775                 if (atomic_read(&rdev->read_errors))
2776                         atomic_set(&rdev->read_errors, 0);
2777         } else {
2778                 int retry = 0;
2779                 int set_bad = 0;
2780
2781                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2782                 if (!(bi->bi_status == BLK_STS_PROTECTION))
2783                         atomic_inc(&rdev->read_errors);
2784                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2785                         pr_warn_ratelimited(
2786                                 "md/raid:%s: read error on replacement device (sector %llu on %pg).\n",
2787                                 mdname(conf->mddev),
2788                                 (unsigned long long)s,
2789                                 rdev->bdev);
2790                 else if (conf->mddev->degraded >= conf->max_degraded) {
2791                         set_bad = 1;
2792                         pr_warn_ratelimited(
2793                                 "md/raid:%s: read error not correctable (sector %llu on %pg).\n",
2794                                 mdname(conf->mddev),
2795                                 (unsigned long long)s,
2796                                 rdev->bdev);
2797                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2798                         /* Oh, no!!! */
2799                         set_bad = 1;
2800                         pr_warn_ratelimited(
2801                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %pg).\n",
2802                                 mdname(conf->mddev),
2803                                 (unsigned long long)s,
2804                                 rdev->bdev);
2805                 } else if (atomic_read(&rdev->read_errors)
2806                          > conf->max_nr_stripes) {
2807                         if (!test_bit(Faulty, &rdev->flags)) {
2808                                 pr_warn("md/raid:%s: %d read_errors > %d stripes\n",
2809                                     mdname(conf->mddev),
2810                                     atomic_read(&rdev->read_errors),
2811                                     conf->max_nr_stripes);
2812                                 pr_warn("md/raid:%s: Too many read errors, failing device %pg.\n",
2813                                     mdname(conf->mddev), rdev->bdev);
2814                         }
2815                 } else
2816                         retry = 1;
2817                 if (set_bad && test_bit(In_sync, &rdev->flags)
2818                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2819                         retry = 1;
2820                 if (retry)
2821                         if (sh->qd_idx >= 0 && sh->pd_idx == i)
2822                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2823                         else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2824                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2825                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2826                         } else
2827                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2828                 else {
2829                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2830                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2831                         if (!(set_bad
2832                               && test_bit(In_sync, &rdev->flags)
2833                               && rdev_set_badblocks(
2834                                       rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)))
2835                                 md_error(conf->mddev, rdev);
2836                 }
2837         }
2838         rdev_dec_pending(rdev, conf->mddev);
2839         bio_uninit(bi);
2840         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2841         set_bit(STRIPE_HANDLE, &sh->state);
2842         raid5_release_stripe(sh);
2843 }
2844
2845 static void raid5_end_write_request(struct bio *bi)
2846 {
2847         struct stripe_head *sh = bi->bi_private;
2848         struct r5conf *conf = sh->raid_conf;
2849         int disks = sh->disks, i;
2850         struct md_rdev *rdev;
2851         int replacement = 0;
2852
2853         for (i = 0 ; i < disks; i++) {
2854                 if (bi == &sh->dev[i].req) {
2855                         rdev = conf->disks[i].rdev;
2856                         break;
2857                 }
2858                 if (bi == &sh->dev[i].rreq) {
2859                         rdev = conf->disks[i].replacement;
2860                         if (rdev)
2861                                 replacement = 1;
2862                         else
2863                                 /* rdev was removed and 'replacement'
2864                                  * replaced it.  rdev is not removed
2865                                  * until all requests are finished.
2866                                  */
2867                                 rdev = conf->disks[i].rdev;
2868                         break;
2869                 }
2870         }
2871         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2872                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2873                 bi->bi_status);
2874         if (i == disks) {
2875                 BUG();
2876                 return;
2877         }
2878
2879         if (replacement) {
2880                 if (bi->bi_status)
2881                         md_error(conf->mddev, rdev);
2882                 else if (rdev_has_badblock(rdev, sh->sector,
2883                                            RAID5_STRIPE_SECTORS(conf)))
2884                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2885         } else {
2886                 if (bi->bi_status) {
2887                         set_bit(STRIPE_DEGRADED, &sh->state);
2888                         set_bit(WriteErrorSeen, &rdev->flags);
2889                         set_bit(R5_WriteError, &sh->dev[i].flags);
2890                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2891                                 set_bit(MD_RECOVERY_NEEDED,
2892                                         &rdev->mddev->recovery);
2893                 } else if (rdev_has_badblock(rdev, sh->sector,
2894                                              RAID5_STRIPE_SECTORS(conf))) {
2895                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2896                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2897                                 /* That was a successful write so make
2898                                  * sure it looks like we already did
2899                                  * a re-write.
2900                                  */
2901                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2902                 }
2903         }
2904         rdev_dec_pending(rdev, conf->mddev);
2905
2906         if (sh->batch_head && bi->bi_status && !replacement)
2907                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2908
2909         bio_uninit(bi);
2910         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2911                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2912         set_bit(STRIPE_HANDLE, &sh->state);
2913
2914         if (sh->batch_head && sh != sh->batch_head)
2915                 raid5_release_stripe(sh->batch_head);
2916         raid5_release_stripe(sh);
2917 }
2918
2919 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2920 {
2921         struct r5conf *conf = mddev->private;
2922         unsigned long flags;
2923         pr_debug("raid456: error called\n");
2924
2925         pr_crit("md/raid:%s: Disk failure on %pg, disabling device.\n",
2926                 mdname(mddev), rdev->bdev);
2927
2928         spin_lock_irqsave(&conf->device_lock, flags);
2929         set_bit(Faulty, &rdev->flags);
2930         clear_bit(In_sync, &rdev->flags);
2931         mddev->degraded = raid5_calc_degraded(conf);
2932
2933         if (has_failed(conf)) {
2934                 set_bit(MD_BROKEN, &conf->mddev->flags);
2935                 conf->recovery_disabled = mddev->recovery_disabled;
2936
2937                 pr_crit("md/raid:%s: Cannot continue operation (%d/%d failed).\n",
2938                         mdname(mddev), mddev->degraded, conf->raid_disks);
2939         } else {
2940                 pr_crit("md/raid:%s: Operation continuing on %d devices.\n",
2941                         mdname(mddev), conf->raid_disks - mddev->degraded);
2942         }
2943
2944         spin_unlock_irqrestore(&conf->device_lock, flags);
2945         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2946
2947         set_bit(Blocked, &rdev->flags);
2948         set_mask_bits(&mddev->sb_flags, 0,
2949                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2950         r5c_update_on_rdev_error(mddev, rdev);
2951 }
2952
2953 /*
2954  * Input: a 'big' sector number,
2955  * Output: index of the data and parity disk, and the sector # in them.
2956  */
2957 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2958                               int previous, int *dd_idx,
2959                               struct stripe_head *sh)
2960 {
2961         sector_t stripe, stripe2;
2962         sector_t chunk_number;
2963         unsigned int chunk_offset;
2964         int pd_idx, qd_idx;
2965         int ddf_layout = 0;
2966         sector_t new_sector;
2967         int algorithm = previous ? conf->prev_algo
2968                                  : conf->algorithm;
2969         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2970                                          : conf->chunk_sectors;
2971         int raid_disks = previous ? conf->previous_raid_disks
2972                                   : conf->raid_disks;
2973         int data_disks = raid_disks - conf->max_degraded;
2974
2975         /* First compute the information on this sector */
2976
2977         /*
2978          * Compute the chunk number and the sector offset inside the chunk
2979          */
2980         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2981         chunk_number = r_sector;
2982
2983         /*
2984          * Compute the stripe number
2985          */
2986         stripe = chunk_number;
2987         *dd_idx = sector_div(stripe, data_disks);
2988         stripe2 = stripe;
2989         /*
2990          * Select the parity disk based on the user selected algorithm.
2991          */
2992         pd_idx = qd_idx = -1;
2993         switch(conf->level) {
2994         case 4:
2995                 pd_idx = data_disks;
2996                 break;
2997         case 5:
2998                 switch (algorithm) {
2999                 case ALGORITHM_LEFT_ASYMMETRIC:
3000                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
3001                         if (*dd_idx >= pd_idx)
3002                                 (*dd_idx)++;
3003                         break;
3004                 case ALGORITHM_RIGHT_ASYMMETRIC:
3005                         pd_idx = sector_div(stripe2, raid_disks);
3006                         if (*dd_idx >= pd_idx)
3007                                 (*dd_idx)++;
3008                         break;
3009                 case ALGORITHM_LEFT_SYMMETRIC:
3010                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
3011                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3012                         break;
3013                 case ALGORITHM_RIGHT_SYMMETRIC:
3014                         pd_idx = sector_div(stripe2, raid_disks);
3015                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3016                         break;
3017                 case ALGORITHM_PARITY_0:
3018                         pd_idx = 0;
3019                         (*dd_idx)++;
3020                         break;
3021                 case ALGORITHM_PARITY_N:
3022                         pd_idx = data_disks;
3023                         break;
3024                 default:
3025                         BUG();
3026                 }
3027                 break;
3028         case 6:
3029
3030                 switch (algorithm) {
3031                 case ALGORITHM_LEFT_ASYMMETRIC:
3032                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3033                         qd_idx = pd_idx + 1;
3034                         if (pd_idx == raid_disks-1) {
3035                                 (*dd_idx)++;    /* Q D D D P */
3036                                 qd_idx = 0;
3037                         } else if (*dd_idx >= pd_idx)
3038                                 (*dd_idx) += 2; /* D D P Q D */
3039                         break;
3040                 case ALGORITHM_RIGHT_ASYMMETRIC:
3041                         pd_idx = sector_div(stripe2, raid_disks);
3042                         qd_idx = pd_idx + 1;
3043                         if (pd_idx == raid_disks-1) {
3044                                 (*dd_idx)++;    /* Q D D D P */
3045                                 qd_idx = 0;
3046                         } else if (*dd_idx >= pd_idx)
3047                                 (*dd_idx) += 2; /* D D P Q D */
3048                         break;
3049                 case ALGORITHM_LEFT_SYMMETRIC:
3050                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3051                         qd_idx = (pd_idx + 1) % raid_disks;
3052                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3053                         break;
3054                 case ALGORITHM_RIGHT_SYMMETRIC:
3055                         pd_idx = sector_div(stripe2, raid_disks);
3056                         qd_idx = (pd_idx + 1) % raid_disks;
3057                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
3058                         break;
3059
3060                 case ALGORITHM_PARITY_0:
3061                         pd_idx = 0;
3062                         qd_idx = 1;
3063                         (*dd_idx) += 2;
3064                         break;
3065                 case ALGORITHM_PARITY_N:
3066                         pd_idx = data_disks;
3067                         qd_idx = data_disks + 1;
3068                         break;
3069
3070                 case ALGORITHM_ROTATING_ZERO_RESTART:
3071                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
3072                          * of blocks for computing Q is different.
3073                          */
3074                         pd_idx = sector_div(stripe2, raid_disks);
3075                         qd_idx = pd_idx + 1;
3076                         if (pd_idx == raid_disks-1) {
3077                                 (*dd_idx)++;    /* Q D D D P */
3078                                 qd_idx = 0;
3079                         } else if (*dd_idx >= pd_idx)
3080                                 (*dd_idx) += 2; /* D D P Q D */
3081                         ddf_layout = 1;
3082                         break;
3083
3084                 case ALGORITHM_ROTATING_N_RESTART:
3085                         /* Same a left_asymmetric, by first stripe is
3086                          * D D D P Q  rather than
3087                          * Q D D D P
3088                          */
3089                         stripe2 += 1;
3090                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3091                         qd_idx = pd_idx + 1;
3092                         if (pd_idx == raid_disks-1) {
3093                                 (*dd_idx)++;    /* Q D D D P */
3094                                 qd_idx = 0;
3095                         } else if (*dd_idx >= pd_idx)
3096                                 (*dd_idx) += 2; /* D D P Q D */
3097                         ddf_layout = 1;
3098                         break;
3099
3100                 case ALGORITHM_ROTATING_N_CONTINUE:
3101                         /* Same as left_symmetric but Q is before P */
3102                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
3103                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
3104                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
3105                         ddf_layout = 1;
3106                         break;
3107
3108                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3109                         /* RAID5 left_asymmetric, with Q on last device */
3110                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3111                         if (*dd_idx >= pd_idx)
3112                                 (*dd_idx)++;
3113                         qd_idx = raid_disks - 1;
3114                         break;
3115
3116                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3117                         pd_idx = sector_div(stripe2, raid_disks-1);
3118                         if (*dd_idx >= pd_idx)
3119                                 (*dd_idx)++;
3120                         qd_idx = raid_disks - 1;
3121                         break;
3122
3123                 case ALGORITHM_LEFT_SYMMETRIC_6:
3124                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
3125                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3126                         qd_idx = raid_disks - 1;
3127                         break;
3128
3129                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3130                         pd_idx = sector_div(stripe2, raid_disks-1);
3131                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
3132                         qd_idx = raid_disks - 1;
3133                         break;
3134
3135                 case ALGORITHM_PARITY_0_6:
3136                         pd_idx = 0;
3137                         (*dd_idx)++;
3138                         qd_idx = raid_disks - 1;
3139                         break;
3140
3141                 default:
3142                         BUG();
3143                 }
3144                 break;
3145         }
3146
3147         if (sh) {
3148                 sh->pd_idx = pd_idx;
3149                 sh->qd_idx = qd_idx;
3150                 sh->ddf_layout = ddf_layout;
3151         }
3152         /*
3153          * Finally, compute the new sector number
3154          */
3155         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
3156         return new_sector;
3157 }
3158
3159 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
3160 {
3161         struct r5conf *conf = sh->raid_conf;
3162         int raid_disks = sh->disks;
3163         int data_disks = raid_disks - conf->max_degraded;
3164         sector_t new_sector = sh->sector, check;
3165         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
3166                                          : conf->chunk_sectors;
3167         int algorithm = previous ? conf->prev_algo
3168                                  : conf->algorithm;
3169         sector_t stripe;
3170         int chunk_offset;
3171         sector_t chunk_number;
3172         int dummy1, dd_idx = i;
3173         sector_t r_sector;
3174         struct stripe_head sh2;
3175
3176         chunk_offset = sector_div(new_sector, sectors_per_chunk);
3177         stripe = new_sector;
3178
3179         if (i == sh->pd_idx)
3180                 return 0;
3181         switch(conf->level) {
3182         case 4: break;
3183         case 5:
3184                 switch (algorithm) {
3185                 case ALGORITHM_LEFT_ASYMMETRIC:
3186                 case ALGORITHM_RIGHT_ASYMMETRIC:
3187                         if (i > sh->pd_idx)
3188                                 i--;
3189                         break;
3190                 case ALGORITHM_LEFT_SYMMETRIC:
3191                 case ALGORITHM_RIGHT_SYMMETRIC:
3192                         if (i < sh->pd_idx)
3193                                 i += raid_disks;
3194                         i -= (sh->pd_idx + 1);
3195                         break;
3196                 case ALGORITHM_PARITY_0:
3197                         i -= 1;
3198                         break;
3199                 case ALGORITHM_PARITY_N:
3200                         break;
3201                 default:
3202                         BUG();
3203                 }
3204                 break;
3205         case 6:
3206                 if (i == sh->qd_idx)
3207                         return 0; /* It is the Q disk */
3208                 switch (algorithm) {
3209                 case ALGORITHM_LEFT_ASYMMETRIC:
3210                 case ALGORITHM_RIGHT_ASYMMETRIC:
3211                 case ALGORITHM_ROTATING_ZERO_RESTART:
3212                 case ALGORITHM_ROTATING_N_RESTART:
3213                         if (sh->pd_idx == raid_disks-1)
3214                                 i--;    /* Q D D D P */
3215                         else if (i > sh->pd_idx)
3216                                 i -= 2; /* D D P Q D */
3217                         break;
3218                 case ALGORITHM_LEFT_SYMMETRIC:
3219                 case ALGORITHM_RIGHT_SYMMETRIC:
3220                         if (sh->pd_idx == raid_disks-1)
3221                                 i--; /* Q D D D P */
3222                         else {
3223                                 /* D D P Q D */
3224                                 if (i < sh->pd_idx)
3225                                         i += raid_disks;
3226                                 i -= (sh->pd_idx + 2);
3227                         }
3228                         break;
3229                 case ALGORITHM_PARITY_0:
3230                         i -= 2;
3231                         break;
3232                 case ALGORITHM_PARITY_N:
3233                         break;
3234                 case ALGORITHM_ROTATING_N_CONTINUE:
3235                         /* Like left_symmetric, but P is before Q */
3236                         if (sh->pd_idx == 0)
3237                                 i--;    /* P D D D Q */
3238                         else {
3239                                 /* D D Q P D */
3240                                 if (i < sh->pd_idx)
3241                                         i += raid_disks;
3242                                 i -= (sh->pd_idx + 1);
3243                         }
3244                         break;
3245                 case ALGORITHM_LEFT_ASYMMETRIC_6:
3246                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
3247                         if (i > sh->pd_idx)
3248                                 i--;
3249                         break;
3250                 case ALGORITHM_LEFT_SYMMETRIC_6:
3251                 case ALGORITHM_RIGHT_SYMMETRIC_6:
3252                         if (i < sh->pd_idx)
3253                                 i += data_disks + 1;
3254                         i -= (sh->pd_idx + 1);
3255                         break;
3256                 case ALGORITHM_PARITY_0_6:
3257                         i -= 1;
3258                         break;
3259                 default:
3260                         BUG();
3261                 }
3262                 break;
3263         }
3264
3265         chunk_number = stripe * data_disks + i;
3266         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3267
3268         check = raid5_compute_sector(conf, r_sector,
3269                                      previous, &dummy1, &sh2);
3270         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3271                 || sh2.qd_idx != sh->qd_idx) {
3272                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3273                         mdname(conf->mddev));
3274                 return 0;
3275         }
3276         return r_sector;
3277 }
3278
3279 /*
3280  * There are cases where we want handle_stripe_dirtying() and
3281  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3282  *
3283  * This function checks whether we want to delay the towrite. Specifically,
3284  * we delay the towrite when:
3285  *
3286  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3287  *      stripe has data in journal (for other devices).
3288  *
3289  *      In this case, when reading data for the non-overwrite dev, it is
3290  *      necessary to handle complex rmw of write back cache (prexor with
3291  *      orig_page, and xor with page). To keep read path simple, we would
3292  *      like to flush data in journal to RAID disks first, so complex rmw
3293  *      is handled in the write patch (handle_stripe_dirtying).
3294  *
3295  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3296  *
3297  *      It is important to be able to flush all stripes in raid5-cache.
3298  *      Therefore, we need reserve some space on the journal device for
3299  *      these flushes. If flush operation includes pending writes to the
3300  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3301  *      for the flush out. If we exclude these pending writes from flush
3302  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3303  *      Therefore, excluding pending writes in these cases enables more
3304  *      efficient use of the journal device.
3305  *
3306  *      Note: To make sure the stripe makes progress, we only delay
3307  *      towrite for stripes with data already in journal (injournal > 0).
3308  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3309  *      no_space_stripes list.
3310  *
3311  *   3. during journal failure
3312  *      In journal failure, we try to flush all cached data to raid disks
3313  *      based on data in stripe cache. The array is read-only to upper
3314  *      layers, so we would skip all pending writes.
3315  *
3316  */
3317 static inline bool delay_towrite(struct r5conf *conf,
3318                                  struct r5dev *dev,
3319                                  struct stripe_head_state *s)
3320 {
3321         /* case 1 above */
3322         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3323             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3324                 return true;
3325         /* case 2 above */
3326         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3327             s->injournal > 0)
3328                 return true;
3329         /* case 3 above */
3330         if (s->log_failed && s->injournal)
3331                 return true;
3332         return false;
3333 }
3334
3335 static void
3336 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3337                          int rcw, int expand)
3338 {
3339         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3340         struct r5conf *conf = sh->raid_conf;
3341         int level = conf->level;
3342
3343         if (rcw) {
3344                 /*
3345                  * In some cases, handle_stripe_dirtying initially decided to
3346                  * run rmw and allocates extra page for prexor. However, rcw is
3347                  * cheaper later on. We need to free the extra page now,
3348                  * because we won't be able to do that in ops_complete_prexor().
3349                  */
3350                 r5c_release_extra_page(sh);
3351
3352                 for (i = disks; i--; ) {
3353                         struct r5dev *dev = &sh->dev[i];
3354
3355                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3356                                 set_bit(R5_LOCKED, &dev->flags);
3357                                 set_bit(R5_Wantdrain, &dev->flags);
3358                                 if (!expand)
3359                                         clear_bit(R5_UPTODATE, &dev->flags);
3360                                 s->locked++;
3361                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3362                                 set_bit(R5_LOCKED, &dev->flags);
3363                                 s->locked++;
3364                         }
3365                 }
3366                 /* if we are not expanding this is a proper write request, and
3367                  * there will be bios with new data to be drained into the
3368                  * stripe cache
3369                  */
3370                 if (!expand) {
3371                         if (!s->locked)
3372                                 /* False alarm, nothing to do */
3373                                 return;
3374                         sh->reconstruct_state = reconstruct_state_drain_run;
3375                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3376                 } else
3377                         sh->reconstruct_state = reconstruct_state_run;
3378
3379                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3380
3381                 if (s->locked + conf->max_degraded == disks)
3382                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3383                                 atomic_inc(&conf->pending_full_writes);
3384         } else {
3385                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3386                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3387                 BUG_ON(level == 6 &&
3388                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3389                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3390
3391                 for (i = disks; i--; ) {
3392                         struct r5dev *dev = &sh->dev[i];
3393                         if (i == pd_idx || i == qd_idx)
3394                                 continue;
3395
3396                         if (dev->towrite &&
3397                             (test_bit(R5_UPTODATE, &dev->flags) ||
3398                              test_bit(R5_Wantcompute, &dev->flags))) {
3399                                 set_bit(R5_Wantdrain, &dev->flags);
3400                                 set_bit(R5_LOCKED, &dev->flags);
3401                                 clear_bit(R5_UPTODATE, &dev->flags);
3402                                 s->locked++;
3403                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3404                                 set_bit(R5_LOCKED, &dev->flags);
3405                                 s->locked++;
3406                         }
3407                 }
3408                 if (!s->locked)
3409                         /* False alarm - nothing to do */
3410                         return;
3411                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3412                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3413                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3414                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3415         }
3416
3417         /* keep the parity disk(s) locked while asynchronous operations
3418          * are in flight
3419          */
3420         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3421         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3422         s->locked++;
3423
3424         if (level == 6) {
3425                 int qd_idx = sh->qd_idx;
3426                 struct r5dev *dev = &sh->dev[qd_idx];
3427
3428                 set_bit(R5_LOCKED, &dev->flags);
3429                 clear_bit(R5_UPTODATE, &dev->flags);
3430                 s->locked++;
3431         }
3432
3433         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3434             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3435             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3436             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3437                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3438
3439         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3440                 __func__, (unsigned long long)sh->sector,
3441                 s->locked, s->ops_request);
3442 }
3443
3444 static bool stripe_bio_overlaps(struct stripe_head *sh, struct bio *bi,
3445                                 int dd_idx, int forwrite)
3446 {
3447         struct r5conf *conf = sh->raid_conf;
3448         struct bio **bip;
3449
3450         pr_debug("checking bi b#%llu to stripe s#%llu\n",
3451                  bi->bi_iter.bi_sector, sh->sector);
3452
3453         /* Don't allow new IO added to stripes in batch list */
3454         if (sh->batch_head)
3455                 return true;
3456
3457         if (forwrite)
3458                 bip = &sh->dev[dd_idx].towrite;
3459         else
3460                 bip = &sh->dev[dd_idx].toread;
3461
3462         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3463                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3464                         return true;
3465                 bip = &(*bip)->bi_next;
3466         }
3467
3468         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3469                 return true;
3470
3471         if (forwrite && raid5_has_ppl(conf)) {
3472                 /*
3473                  * With PPL only writes to consecutive data chunks within a
3474                  * stripe are allowed because for a single stripe_head we can
3475                  * only have one PPL entry at a time, which describes one data
3476                  * range. Not really an overlap, but R5_Overlap can be
3477                  * used to handle this.
3478                  */
3479                 sector_t sector;
3480                 sector_t first = 0;
3481                 sector_t last = 0;
3482                 int count = 0;
3483                 int i;
3484
3485                 for (i = 0; i < sh->disks; i++) {
3486                         if (i != sh->pd_idx &&
3487                             (i == dd_idx || sh->dev[i].towrite)) {
3488                                 sector = sh->dev[i].sector;
3489                                 if (count == 0 || sector < first)
3490                                         first = sector;
3491                                 if (sector > last)
3492                                         last = sector;
3493                                 count++;
3494                         }
3495                 }
3496
3497                 if (first + conf->chunk_sectors * (count - 1) != last)
3498                         return true;
3499         }
3500
3501         return false;
3502 }
3503
3504 static void __add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3505                              int dd_idx, int forwrite, int previous)
3506 {
3507         struct r5conf *conf = sh->raid_conf;
3508         struct bio **bip;
3509         int firstwrite = 0;
3510
3511         if (forwrite) {
3512                 bip = &sh->dev[dd_idx].towrite;
3513                 if (!*bip)
3514                         firstwrite = 1;
3515         } else {
3516                 bip = &sh->dev[dd_idx].toread;
3517         }
3518
3519         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector)
3520                 bip = &(*bip)->bi_next;
3521
3522         if (!forwrite || previous)
3523                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3524
3525         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3526         if (*bip)
3527                 bi->bi_next = *bip;
3528         *bip = bi;
3529         bio_inc_remaining(bi);
3530         md_write_inc(conf->mddev, bi);
3531
3532         if (forwrite) {
3533                 /* check if page is covered */
3534                 sector_t sector = sh->dev[dd_idx].sector;
3535                 for (bi=sh->dev[dd_idx].towrite;
3536                      sector < sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf) &&
3537                              bi && bi->bi_iter.bi_sector <= sector;
3538                      bi = r5_next_bio(conf, bi, sh->dev[dd_idx].sector)) {
3539                         if (bio_end_sector(bi) >= sector)
3540                                 sector = bio_end_sector(bi);
3541                 }
3542                 if (sector >= sh->dev[dd_idx].sector + RAID5_STRIPE_SECTORS(conf))
3543                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3544                                 sh->overwrite_disks++;
3545         }
3546
3547         pr_debug("added bi b#%llu to stripe s#%llu, disk %d, logical %llu\n",
3548                  (*bip)->bi_iter.bi_sector, sh->sector, dd_idx,
3549                  sh->dev[dd_idx].sector);
3550
3551         if (conf->mddev->bitmap && firstwrite) {
3552                 /* Cannot hold spinlock over bitmap_startwrite,
3553                  * but must ensure this isn't added to a batch until
3554                  * we have added to the bitmap and set bm_seq.
3555                  * So set STRIPE_BITMAP_PENDING to prevent
3556                  * batching.
3557                  * If multiple __add_stripe_bio() calls race here they
3558                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3559                  * to complete "bitmap_startwrite" gets to set
3560                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3561                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3562                  * any more.
3563                  */
3564                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3565                 spin_unlock_irq(&sh->stripe_lock);
3566                 conf->mddev->bitmap_ops->startwrite(conf->mddev, sh->sector,
3567                                         RAID5_STRIPE_SECTORS(conf), false);
3568                 spin_lock_irq(&sh->stripe_lock);
3569                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3570                 if (!sh->batch_head) {
3571                         sh->bm_seq = conf->seq_flush+1;
3572                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3573                 }
3574         }
3575 }
3576
3577 /*
3578  * Each stripe/dev can have one or more bios attached.
3579  * toread/towrite point to the first in a chain.
3580  * The bi_next chain must be in order.
3581  */
3582 static bool add_stripe_bio(struct stripe_head *sh, struct bio *bi,
3583                            int dd_idx, int forwrite, int previous)
3584 {
3585         spin_lock_irq(&sh->stripe_lock);
3586
3587         if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
3588                 set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3589                 spin_unlock_irq(&sh->stripe_lock);
3590                 return false;
3591         }
3592
3593         __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
3594         spin_unlock_irq(&sh->stripe_lock);
3595         return true;
3596 }
3597
3598 static void end_reshape(struct r5conf *conf);
3599
3600 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3601                             struct stripe_head *sh)
3602 {
3603         int sectors_per_chunk =
3604                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3605         int dd_idx;
3606         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3607         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3608
3609         raid5_compute_sector(conf,
3610                              stripe * (disks - conf->max_degraded)
3611                              *sectors_per_chunk + chunk_offset,
3612                              previous,
3613                              &dd_idx, sh);
3614 }
3615
3616 static void
3617 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3618                      struct stripe_head_state *s, int disks)
3619 {
3620         int i;
3621         BUG_ON(sh->batch_head);
3622         for (i = disks; i--; ) {
3623                 struct bio *bi;
3624                 int bitmap_end = 0;
3625
3626                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3627                         struct md_rdev *rdev = conf->disks[i].rdev;
3628
3629                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3630                             !test_bit(Faulty, &rdev->flags))
3631                                 atomic_inc(&rdev->nr_pending);
3632                         else
3633                                 rdev = NULL;
3634                         if (rdev) {
3635                                 if (!rdev_set_badblocks(
3636                                             rdev,
3637                                             sh->sector,
3638                                             RAID5_STRIPE_SECTORS(conf), 0))
3639                                         md_error(conf->mddev, rdev);
3640                                 rdev_dec_pending(rdev, conf->mddev);
3641                         }
3642                 }
3643                 spin_lock_irq(&sh->stripe_lock);
3644                 /* fail all writes first */
3645                 bi = sh->dev[i].towrite;
3646                 sh->dev[i].towrite = NULL;
3647                 sh->overwrite_disks = 0;
3648                 spin_unlock_irq(&sh->stripe_lock);
3649                 if (bi)
3650                         bitmap_end = 1;
3651
3652                 log_stripe_write_finished(sh);
3653
3654                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3655                         wake_up_bit(&sh->dev[i].flags, R5_Overlap);
3656
3657                 while (bi && bi->bi_iter.bi_sector <
3658                         sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3659                         struct bio *nextbi = r5_next_bio(conf, bi, sh->dev[i].sector);
3660
3661                         md_write_end(conf->mddev);
3662                         bio_io_error(bi);
3663                         bi = nextbi;
3664                 }
3665                 if (bitmap_end)
3666                         conf->mddev->bitmap_ops->endwrite(conf->mddev,
3667                                         sh->sector, RAID5_STRIPE_SECTORS(conf),
3668                                         false, false);
3669                 bitmap_end = 0;
3670                 /* and fail all 'written' */
3671                 bi = sh->dev[i].written;
3672                 sh->dev[i].written = NULL;
3673                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3674                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3675                         sh->dev[i].page = sh->dev[i].orig_page;
3676                 }
3677
3678                 if (bi) bitmap_end = 1;
3679                 while (bi && bi->bi_iter.bi_sector <
3680                        sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3681                         struct bio *bi2 = r5_next_bio(conf, bi, sh->dev[i].sector);
3682
3683                         md_write_end(conf->mddev);
3684                         bio_io_error(bi);
3685                         bi = bi2;
3686                 }
3687
3688                 /* fail any reads if this device is non-operational and
3689                  * the data has not reached the cache yet.
3690                  */
3691                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3692                     s->failed > conf->max_degraded &&
3693                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3694                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3695                         spin_lock_irq(&sh->stripe_lock);
3696                         bi = sh->dev[i].toread;
3697                         sh->dev[i].toread = NULL;
3698                         spin_unlock_irq(&sh->stripe_lock);
3699                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3700                                 wake_up_bit(&sh->dev[i].flags, R5_Overlap);
3701                         if (bi)
3702                                 s->to_read--;
3703                         while (bi && bi->bi_iter.bi_sector <
3704                                sh->dev[i].sector + RAID5_STRIPE_SECTORS(conf)) {
3705                                 struct bio *nextbi =
3706                                         r5_next_bio(conf, bi, sh->dev[i].sector);
3707
3708                                 bio_io_error(bi);
3709                                 bi = nextbi;
3710                         }
3711                 }
3712                 if (bitmap_end)
3713                         conf->mddev->bitmap_ops->endwrite(conf->mddev,
3714                                         sh->sector, RAID5_STRIPE_SECTORS(conf),
3715                                         false, false);
3716                 /* If we were in the middle of a write the parity block might
3717                  * still be locked - so just clear all R5_LOCKED flags
3718                  */
3719                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3720         }
3721         s->to_write = 0;
3722         s->written = 0;
3723
3724         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3725                 if (atomic_dec_and_test(&conf->pending_full_writes))
3726                         md_wakeup_thread(conf->mddev->thread);
3727 }
3728
3729 static void
3730 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3731                    struct stripe_head_state *s)
3732 {
3733         int abort = 0;
3734         int i;
3735
3736         BUG_ON(sh->batch_head);
3737         clear_bit(STRIPE_SYNCING, &sh->state);
3738         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3739                 wake_up_bit(&sh->dev[sh->pd_idx].flags, R5_Overlap);
3740         s->syncing = 0;
3741         s->replacing = 0;
3742         /* There is nothing more to do for sync/check/repair.
3743          * Don't even need to abort as that is handled elsewhere
3744          * if needed, and not always wanted e.g. if there is a known
3745          * bad block here.
3746          * For recover/replace we need to record a bad block on all
3747          * non-sync devices, or abort the recovery
3748          */
3749         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3750                 /* During recovery devices cannot be removed, so
3751                  * locking and refcounting of rdevs is not needed
3752                  */
3753                 for (i = 0; i < conf->raid_disks; i++) {
3754                         struct md_rdev *rdev = conf->disks[i].rdev;
3755
3756                         if (rdev
3757                             && !test_bit(Faulty, &rdev->flags)
3758                             && !test_bit(In_sync, &rdev->flags)
3759                             && !rdev_set_badblocks(rdev, sh->sector,
3760                                                    RAID5_STRIPE_SECTORS(conf), 0))
3761                                 abort = 1;
3762                         rdev = conf->disks[i].replacement;
3763
3764                         if (rdev
3765                             && !test_bit(Faulty, &rdev->flags)
3766                             && !test_bit(In_sync, &rdev->flags)
3767                             && !rdev_set_badblocks(rdev, sh->sector,
3768                                                    RAID5_STRIPE_SECTORS(conf), 0))
3769                                 abort = 1;
3770                 }
3771                 if (abort)
3772                         conf->recovery_disabled =
3773                                 conf->mddev->recovery_disabled;
3774         }
3775         md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), !abort);
3776 }
3777
3778 static int want_replace(struct stripe_head *sh, int disk_idx)
3779 {
3780         struct md_rdev *rdev;
3781         int rv = 0;
3782
3783         rdev = sh->raid_conf->disks[disk_idx].replacement;
3784         if (rdev
3785             && !test_bit(Faulty, &rdev->flags)
3786             && !test_bit(In_sync, &rdev->flags)
3787             && (rdev->recovery_offset <= sh->sector
3788                 || rdev->mddev->recovery_cp <= sh->sector))
3789                 rv = 1;
3790         return rv;
3791 }
3792
3793 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3794                            int disk_idx, int disks)
3795 {
3796         struct r5dev *dev = &sh->dev[disk_idx];
3797         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3798                                   &sh->dev[s->failed_num[1]] };
3799         int i;
3800         bool force_rcw = (sh->raid_conf->rmw_level == PARITY_DISABLE_RMW);
3801
3802
3803         if (test_bit(R5_LOCKED, &dev->flags) ||
3804             test_bit(R5_UPTODATE, &dev->flags))
3805                 /* No point reading this as we already have it or have
3806                  * decided to get it.
3807                  */
3808                 return 0;
3809
3810         if (dev->toread ||
3811             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3812                 /* We need this block to directly satisfy a request */
3813                 return 1;
3814
3815         if (s->syncing || s->expanding ||
3816             (s->replacing && want_replace(sh, disk_idx)))
3817                 /* When syncing, or expanding we read everything.
3818                  * When replacing, we need the replaced block.
3819                  */
3820                 return 1;
3821
3822         if ((s->failed >= 1 && fdev[0]->toread) ||
3823             (s->failed >= 2 && fdev[1]->toread))
3824                 /* If we want to read from a failed device, then
3825                  * we need to actually read every other device.
3826                  */
3827                 return 1;
3828
3829         /* Sometimes neither read-modify-write nor reconstruct-write
3830          * cycles can work.  In those cases we read every block we
3831          * can.  Then the parity-update is certain to have enough to
3832          * work with.
3833          * This can only be a problem when we need to write something,
3834          * and some device has failed.  If either of those tests
3835          * fail we need look no further.
3836          */
3837         if (!s->failed || !s->to_write)
3838                 return 0;
3839
3840         if (test_bit(R5_Insync, &dev->flags) &&
3841             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3842                 /* Pre-reads at not permitted until after short delay
3843                  * to gather multiple requests.  However if this
3844                  * device is no Insync, the block could only be computed
3845                  * and there is no need to delay that.
3846                  */
3847                 return 0;
3848
3849         for (i = 0; i < s->failed && i < 2; i++) {
3850                 if (fdev[i]->towrite &&
3851                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3852                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3853                         /* If we have a partial write to a failed
3854                          * device, then we will need to reconstruct
3855                          * the content of that device, so all other
3856                          * devices must be read.
3857                          */
3858                         return 1;
3859
3860                 if (s->failed >= 2 &&
3861                     (fdev[i]->towrite ||
3862                      s->failed_num[i] == sh->pd_idx ||
3863                      s->failed_num[i] == sh->qd_idx) &&
3864                     !test_bit(R5_UPTODATE, &fdev[i]->flags))
3865                         /* In max degraded raid6, If the failed disk is P, Q,
3866                          * or we want to read the failed disk, we need to do
3867                          * reconstruct-write.
3868                          */
3869                         force_rcw = true;
3870         }
3871
3872         /* If we are forced to do a reconstruct-write, because parity
3873          * cannot be trusted and we are currently recovering it, there
3874          * is extra need to be careful.
3875          * If one of the devices that we would need to read, because
3876          * it is not being overwritten (and maybe not written at all)
3877          * is missing/faulty, then we need to read everything we can.
3878          */
3879         if (!force_rcw &&
3880             sh->sector < sh->raid_conf->mddev->recovery_cp)
3881                 /* reconstruct-write isn't being forced */
3882                 return 0;
3883         for (i = 0; i < s->failed && i < 2; i++) {
3884                 if (s->failed_num[i] != sh->pd_idx &&
3885                     s->failed_num[i] != sh->qd_idx &&
3886                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3887                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3888                         return 1;
3889         }
3890
3891         return 0;
3892 }
3893
3894 /* fetch_block - checks the given member device to see if its data needs
3895  * to be read or computed to satisfy a request.
3896  *
3897  * Returns 1 when no more member devices need to be checked, otherwise returns
3898  * 0 to tell the loop in handle_stripe_fill to continue
3899  */
3900 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3901                        int disk_idx, int disks)
3902 {
3903         struct r5dev *dev = &sh->dev[disk_idx];
3904
3905         /* is the data in this block needed, and can we get it? */
3906         if (need_this_block(sh, s, disk_idx, disks)) {
3907                 /* we would like to get this block, possibly by computing it,
3908                  * otherwise read it if the backing disk is insync
3909                  */
3910                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3911                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3912                 BUG_ON(sh->batch_head);
3913
3914                 /*
3915                  * In the raid6 case if the only non-uptodate disk is P
3916                  * then we already trusted P to compute the other failed
3917                  * drives. It is safe to compute rather than re-read P.
3918                  * In other cases we only compute blocks from failed
3919                  * devices, otherwise check/repair might fail to detect
3920                  * a real inconsistency.
3921                  */
3922
3923                 if ((s->uptodate == disks - 1) &&
3924                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3925                     (s->failed && (disk_idx == s->failed_num[0] ||
3926                                    disk_idx == s->failed_num[1])))) {
3927                         /* have disk failed, and we're requested to fetch it;
3928                          * do compute it
3929                          */
3930                         pr_debug("Computing stripe %llu block %d\n",
3931                                (unsigned long long)sh->sector, disk_idx);
3932                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3933                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3934                         set_bit(R5_Wantcompute, &dev->flags);
3935                         sh->ops.target = disk_idx;
3936                         sh->ops.target2 = -1; /* no 2nd target */
3937                         s->req_compute = 1;
3938                         /* Careful: from this point on 'uptodate' is in the eye
3939                          * of raid_run_ops which services 'compute' operations
3940                          * before writes. R5_Wantcompute flags a block that will
3941                          * be R5_UPTODATE by the time it is needed for a
3942                          * subsequent operation.
3943                          */
3944                         s->uptodate++;
3945                         return 1;
3946                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3947                         /* Computing 2-failure is *very* expensive; only
3948                          * do it if failed >= 2
3949                          */
3950                         int other;
3951                         for (other = disks; other--; ) {
3952                                 if (other == disk_idx)
3953                                         continue;
3954                                 if (!test_bit(R5_UPTODATE,
3955                                       &sh->dev[other].flags))
3956                                         break;
3957                         }
3958                         BUG_ON(other < 0);
3959                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3960                                (unsigned long long)sh->sector,
3961                                disk_idx, other);
3962                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3963                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3964                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3965                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3966                         sh->ops.target = disk_idx;
3967                         sh->ops.target2 = other;
3968                         s->uptodate += 2;
3969                         s->req_compute = 1;
3970                         return 1;
3971                 } else if (test_bit(R5_Insync, &dev->flags)) {
3972                         set_bit(R5_LOCKED, &dev->flags);
3973                         set_bit(R5_Wantread, &dev->flags);
3974                         s->locked++;
3975                         pr_debug("Reading block %d (sync=%d)\n",
3976                                 disk_idx, s->syncing);
3977                 }
3978         }
3979
3980         return 0;
3981 }
3982
3983 /*
3984  * handle_stripe_fill - read or compute data to satisfy pending requests.
3985  */
3986 static void handle_stripe_fill(struct stripe_head *sh,
3987                                struct stripe_head_state *s,
3988                                int disks)
3989 {
3990         int i;
3991
3992         /* look for blocks to read/compute, skip this if a compute
3993          * is already in flight, or if the stripe contents are in the
3994          * midst of changing due to a write
3995          */
3996         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3997             !sh->reconstruct_state) {
3998
3999                 /*
4000                  * For degraded stripe with data in journal, do not handle
4001                  * read requests yet, instead, flush the stripe to raid
4002                  * disks first, this avoids handling complex rmw of write
4003                  * back cache (prexor with orig_page, and then xor with
4004                  * page) in the read path
4005                  */
4006                 if (s->to_read && s->injournal && s->failed) {
4007                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
4008                                 r5c_make_stripe_write_out(sh);
4009                         goto out;
4010                 }
4011
4012                 for (i = disks; i--; )
4013                         if (fetch_block(sh, s, i, disks))
4014                                 break;
4015         }
4016 out:
4017         set_bit(STRIPE_HANDLE, &sh->state);
4018 }
4019
4020 static void break_stripe_batch_list(struct stripe_head *head_sh,
4021                                     unsigned long handle_flags);
4022 /* handle_stripe_clean_event
4023  * any written block on an uptodate or failed drive can be returned.
4024  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
4025  * never LOCKED, so we don't need to test 'failed' directly.
4026  */
4027 static void handle_stripe_clean_event(struct r5conf *conf,
4028         struct stripe_head *sh, int disks)
4029 {
4030         int i;
4031         struct r5dev *dev;
4032         int discard_pending = 0;
4033         struct stripe_head *head_sh = sh;
4034         bool do_endio = false;
4035
4036         for (i = disks; i--; )
4037                 if (sh->dev[i].written) {
4038                         dev = &sh->dev[i];
4039                         if (!test_bit(R5_LOCKED, &dev->flags) &&
4040                             (test_bit(R5_UPTODATE, &dev->flags) ||
4041                              test_bit(R5_Discard, &dev->flags) ||
4042                              test_bit(R5_SkipCopy, &dev->flags))) {
4043                                 /* We can return any write requests */
4044                                 struct bio *wbi, *wbi2;
4045                                 pr_debug("Return write for disc %d\n", i);
4046                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
4047                                         clear_bit(R5_UPTODATE, &dev->flags);
4048                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
4049                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
4050                                 }
4051                                 do_endio = true;
4052
4053 returnbi:
4054                                 dev->page = dev->orig_page;
4055                                 wbi = dev->written;
4056                                 dev->written = NULL;
4057                                 while (wbi && wbi->bi_iter.bi_sector <
4058                                         dev->sector + RAID5_STRIPE_SECTORS(conf)) {
4059                                         wbi2 = r5_next_bio(conf, wbi, dev->sector);
4060                                         md_write_end(conf->mddev);
4061                                         bio_endio(wbi);
4062                                         wbi = wbi2;
4063                                 }
4064                                 conf->mddev->bitmap_ops->endwrite(conf->mddev,
4065                                         sh->sector, RAID5_STRIPE_SECTORS(conf),
4066                                         !test_bit(STRIPE_DEGRADED, &sh->state),
4067                                         false);
4068                                 if (head_sh->batch_head) {
4069                                         sh = list_first_entry(&sh->batch_list,
4070                                                               struct stripe_head,
4071                                                               batch_list);
4072                                         if (sh != head_sh) {
4073                                                 dev = &sh->dev[i];
4074                                                 goto returnbi;
4075                                         }
4076                                 }
4077                                 sh = head_sh;
4078                                 dev = &sh->dev[i];
4079                         } else if (test_bit(R5_Discard, &dev->flags))
4080                                 discard_pending = 1;
4081                 }
4082
4083         log_stripe_write_finished(sh);
4084
4085         if (!discard_pending &&
4086             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
4087                 int hash;
4088                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
4089                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4090                 if (sh->qd_idx >= 0) {
4091                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
4092                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
4093                 }
4094                 /* now that discard is done we can proceed with any sync */
4095                 clear_bit(STRIPE_DISCARD, &sh->state);
4096                 /*
4097                  * SCSI discard will change some bio fields and the stripe has
4098                  * no updated data, so remove it from hash list and the stripe
4099                  * will be reinitialized
4100                  */
4101 unhash:
4102                 hash = sh->hash_lock_index;
4103                 spin_lock_irq(conf->hash_locks + hash);
4104                 remove_hash(sh);
4105                 spin_unlock_irq(conf->hash_locks + hash);
4106                 if (head_sh->batch_head) {
4107                         sh = list_first_entry(&sh->batch_list,
4108                                               struct stripe_head, batch_list);
4109                         if (sh != head_sh)
4110                                         goto unhash;
4111                 }
4112                 sh = head_sh;
4113
4114                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
4115                         set_bit(STRIPE_HANDLE, &sh->state);
4116
4117         }
4118
4119         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
4120                 if (atomic_dec_and_test(&conf->pending_full_writes))
4121                         md_wakeup_thread(conf->mddev->thread);
4122
4123         if (head_sh->batch_head && do_endio)
4124                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
4125 }
4126
4127 /*
4128  * For RMW in write back cache, we need extra page in prexor to store the
4129  * old data. This page is stored in dev->orig_page.
4130  *
4131  * This function checks whether we have data for prexor. The exact logic
4132  * is:
4133  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
4134  */
4135 static inline bool uptodate_for_rmw(struct r5dev *dev)
4136 {
4137         return (test_bit(R5_UPTODATE, &dev->flags)) &&
4138                 (!test_bit(R5_InJournal, &dev->flags) ||
4139                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
4140 }
4141
4142 static int handle_stripe_dirtying(struct r5conf *conf,
4143                                   struct stripe_head *sh,
4144                                   struct stripe_head_state *s,
4145                                   int disks)
4146 {
4147         int rmw = 0, rcw = 0, i;
4148         sector_t recovery_cp = conf->mddev->recovery_cp;
4149
4150         /* Check whether resync is now happening or should start.
4151          * If yes, then the array is dirty (after unclean shutdown or
4152          * initial creation), so parity in some stripes might be inconsistent.
4153          * In this case, we need to always do reconstruct-write, to ensure
4154          * that in case of drive failure or read-error correction, we
4155          * generate correct data from the parity.
4156          */
4157         if (conf->rmw_level == PARITY_DISABLE_RMW ||
4158             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
4159              s->failed == 0)) {
4160                 /* Calculate the real rcw later - for now make it
4161                  * look like rcw is cheaper
4162                  */
4163                 rcw = 1; rmw = 2;
4164                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
4165                          conf->rmw_level, (unsigned long long)recovery_cp,
4166                          (unsigned long long)sh->sector);
4167         } else for (i = disks; i--; ) {
4168                 /* would I have to read this buffer for read_modify_write */
4169                 struct r5dev *dev = &sh->dev[i];
4170                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4171                      i == sh->pd_idx || i == sh->qd_idx ||
4172                      test_bit(R5_InJournal, &dev->flags)) &&
4173                     !test_bit(R5_LOCKED, &dev->flags) &&
4174                     !(uptodate_for_rmw(dev) ||
4175                       test_bit(R5_Wantcompute, &dev->flags))) {
4176                         if (test_bit(R5_Insync, &dev->flags))
4177                                 rmw++;
4178                         else
4179                                 rmw += 2*disks;  /* cannot read it */
4180                 }
4181                 /* Would I have to read this buffer for reconstruct_write */
4182                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4183                     i != sh->pd_idx && i != sh->qd_idx &&
4184                     !test_bit(R5_LOCKED, &dev->flags) &&
4185                     !(test_bit(R5_UPTODATE, &dev->flags) ||
4186                       test_bit(R5_Wantcompute, &dev->flags))) {
4187                         if (test_bit(R5_Insync, &dev->flags))
4188                                 rcw++;
4189                         else
4190                                 rcw += 2*disks;
4191                 }
4192         }
4193
4194         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
4195                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
4196         set_bit(STRIPE_HANDLE, &sh->state);
4197         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
4198                 /* prefer read-modify-write, but need to get some data */
4199                 mddev_add_trace_msg(conf->mddev, "raid5 rmw %llu %d",
4200                                 sh->sector, rmw);
4201
4202                 for (i = disks; i--; ) {
4203                         struct r5dev *dev = &sh->dev[i];
4204                         if (test_bit(R5_InJournal, &dev->flags) &&
4205                             dev->page == dev->orig_page &&
4206                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
4207                                 /* alloc page for prexor */
4208                                 struct page *p = alloc_page(GFP_NOIO);
4209
4210                                 if (p) {
4211                                         dev->orig_page = p;
4212                                         continue;
4213                                 }
4214
4215                                 /*
4216                                  * alloc_page() failed, try use
4217                                  * disk_info->extra_page
4218                                  */
4219                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
4220                                                       &conf->cache_state)) {
4221                                         r5c_use_extra_page(sh);
4222                                         break;
4223                                 }
4224
4225                                 /* extra_page in use, add to delayed_list */
4226                                 set_bit(STRIPE_DELAYED, &sh->state);
4227                                 s->waiting_extra_page = 1;
4228                                 return -EAGAIN;
4229                         }
4230                 }
4231
4232                 for (i = disks; i--; ) {
4233                         struct r5dev *dev = &sh->dev[i];
4234                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
4235                              i == sh->pd_idx || i == sh->qd_idx ||
4236                              test_bit(R5_InJournal, &dev->flags)) &&
4237                             !test_bit(R5_LOCKED, &dev->flags) &&
4238                             !(uptodate_for_rmw(dev) ||
4239                               test_bit(R5_Wantcompute, &dev->flags)) &&
4240                             test_bit(R5_Insync, &dev->flags)) {
4241                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
4242                                              &sh->state)) {
4243                                         pr_debug("Read_old block %d for r-m-w\n",
4244                                                  i);
4245                                         set_bit(R5_LOCKED, &dev->flags);
4246                                         set_bit(R5_Wantread, &dev->flags);
4247                                         s->locked++;
4248                                 } else
4249                                         set_bit(STRIPE_DELAYED, &sh->state);
4250                         }
4251                 }
4252         }
4253         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
4254                 /* want reconstruct write, but need to get some data */
4255                 int qread =0;
4256                 rcw = 0;
4257                 for (i = disks; i--; ) {
4258                         struct r5dev *dev = &sh->dev[i];
4259                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
4260                             i != sh->pd_idx && i != sh->qd_idx &&
4261                             !test_bit(R5_LOCKED, &dev->flags) &&
4262                             !(test_bit(R5_UPTODATE, &dev->flags) ||
4263                               test_bit(R5_Wantcompute, &dev->flags))) {
4264                                 rcw++;
4265                                 if (test_bit(R5_Insync, &dev->flags) &&
4266                                     test_bit(STRIPE_PREREAD_ACTIVE,
4267                                              &sh->state)) {
4268                                         pr_debug("Read_old block "
4269                                                 "%d for Reconstruct\n", i);
4270                                         set_bit(R5_LOCKED, &dev->flags);
4271                                         set_bit(R5_Wantread, &dev->flags);
4272                                         s->locked++;
4273                                         qread++;
4274                                 } else
4275                                         set_bit(STRIPE_DELAYED, &sh->state);
4276                         }
4277                 }
4278                 if (rcw && !mddev_is_dm(conf->mddev))
4279                         blk_add_trace_msg(conf->mddev->gendisk->queue,
4280                                 "raid5 rcw %llu %d %d %d",
4281                                 (unsigned long long)sh->sector, rcw, qread,
4282                                 test_bit(STRIPE_DELAYED, &sh->state));
4283         }
4284
4285         if (rcw > disks && rmw > disks &&
4286             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4287                 set_bit(STRIPE_DELAYED, &sh->state);
4288
4289         /* now if nothing is locked, and if we have enough data,
4290          * we can start a write request
4291          */
4292         /* since handle_stripe can be called at any time we need to handle the
4293          * case where a compute block operation has been submitted and then a
4294          * subsequent call wants to start a write request.  raid_run_ops only
4295          * handles the case where compute block and reconstruct are requested
4296          * simultaneously.  If this is not the case then new writes need to be
4297          * held off until the compute completes.
4298          */
4299         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4300             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4301              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4302                 schedule_reconstruction(sh, s, rcw == 0, 0);
4303         return 0;
4304 }
4305
4306 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4307                                 struct stripe_head_state *s, int disks)
4308 {
4309         struct r5dev *dev = NULL;
4310
4311         BUG_ON(sh->batch_head);
4312         set_bit(STRIPE_HANDLE, &sh->state);
4313
4314         switch (sh->check_state) {
4315         case check_state_idle:
4316                 /* start a new check operation if there are no failures */
4317                 if (s->failed == 0) {
4318                         BUG_ON(s->uptodate != disks);
4319                         sh->check_state = check_state_run;
4320                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4321                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4322                         s->uptodate--;
4323                         break;
4324                 }
4325                 dev = &sh->dev[s->failed_num[0]];
4326                 fallthrough;
4327         case check_state_compute_result:
4328                 sh->check_state = check_state_idle;
4329                 if (!dev)
4330                         dev = &sh->dev[sh->pd_idx];
4331
4332                 /* check that a write has not made the stripe insync */
4333                 if (test_bit(STRIPE_INSYNC, &sh->state))
4334                         break;
4335
4336                 /* either failed parity check, or recovery is happening */
4337                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4338                 BUG_ON(s->uptodate != disks);
4339
4340                 set_bit(R5_LOCKED, &dev->flags);
4341                 s->locked++;
4342                 set_bit(R5_Wantwrite, &dev->flags);
4343
4344                 clear_bit(STRIPE_DEGRADED, &sh->state);
4345                 set_bit(STRIPE_INSYNC, &sh->state);
4346                 break;
4347         case check_state_run:
4348                 break; /* we will be called again upon completion */
4349         case check_state_check_result:
4350                 sh->check_state = check_state_idle;
4351
4352                 /* if a failure occurred during the check operation, leave
4353                  * STRIPE_INSYNC not set and let the stripe be handled again
4354                  */
4355                 if (s->failed)
4356                         break;
4357
4358                 /* handle a successful check operation, if parity is correct
4359                  * we are done.  Otherwise update the mismatch count and repair
4360                  * parity if !MD_RECOVERY_CHECK
4361                  */
4362                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4363                         /* parity is correct (on disc,
4364                          * not in buffer any more)
4365                          */
4366                         set_bit(STRIPE_INSYNC, &sh->state);
4367                 else {
4368                         atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4369                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4370                                 /* don't try to repair!! */
4371                                 set_bit(STRIPE_INSYNC, &sh->state);
4372                                 pr_warn_ratelimited("%s: mismatch sector in range "
4373                                                     "%llu-%llu\n", mdname(conf->mddev),
4374                                                     (unsigned long long) sh->sector,
4375                                                     (unsigned long long) sh->sector +
4376                                                     RAID5_STRIPE_SECTORS(conf));
4377                         } else {
4378                                 sh->check_state = check_state_compute_run;
4379                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4380                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4381                                 set_bit(R5_Wantcompute,
4382                                         &sh->dev[sh->pd_idx].flags);
4383                                 sh->ops.target = sh->pd_idx;
4384                                 sh->ops.target2 = -1;
4385                                 s->uptodate++;
4386                         }
4387                 }
4388                 break;
4389         case check_state_compute_run:
4390                 break;
4391         default:
4392                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4393                        __func__, sh->check_state,
4394                        (unsigned long long) sh->sector);
4395                 BUG();
4396         }
4397 }
4398
4399 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4400                                   struct stripe_head_state *s,
4401                                   int disks)
4402 {
4403         int pd_idx = sh->pd_idx;
4404         int qd_idx = sh->qd_idx;
4405         struct r5dev *dev;
4406
4407         BUG_ON(sh->batch_head);
4408         set_bit(STRIPE_HANDLE, &sh->state);
4409
4410         BUG_ON(s->failed > 2);
4411
4412         /* Want to check and possibly repair P and Q.
4413          * However there could be one 'failed' device, in which
4414          * case we can only check one of them, possibly using the
4415          * other to generate missing data
4416          */
4417
4418         switch (sh->check_state) {
4419         case check_state_idle:
4420                 /* start a new check operation if there are < 2 failures */
4421                 if (s->failed == s->q_failed) {
4422                         /* The only possible failed device holds Q, so it
4423                          * makes sense to check P (If anything else were failed,
4424                          * we would have used P to recreate it).
4425                          */
4426                         sh->check_state = check_state_run;
4427                 }
4428                 if (!s->q_failed && s->failed < 2) {
4429                         /* Q is not failed, and we didn't use it to generate
4430                          * anything, so it makes sense to check it
4431                          */
4432                         if (sh->check_state == check_state_run)
4433                                 sh->check_state = check_state_run_pq;
4434                         else
4435                                 sh->check_state = check_state_run_q;
4436                 }
4437
4438                 /* discard potentially stale zero_sum_result */
4439                 sh->ops.zero_sum_result = 0;
4440
4441                 if (sh->check_state == check_state_run) {
4442                         /* async_xor_zero_sum destroys the contents of P */
4443                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4444                         s->uptodate--;
4445                 }
4446                 if (sh->check_state >= check_state_run &&
4447                     sh->check_state <= check_state_run_pq) {
4448                         /* async_syndrome_zero_sum preserves P and Q, so
4449                          * no need to mark them !uptodate here
4450                          */
4451                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4452                         break;
4453                 }
4454
4455                 /* we have 2-disk failure */
4456                 BUG_ON(s->failed != 2);
4457                 fallthrough;
4458         case check_state_compute_result:
4459                 sh->check_state = check_state_idle;
4460
4461                 /* check that a write has not made the stripe insync */
4462                 if (test_bit(STRIPE_INSYNC, &sh->state))
4463                         break;
4464
4465                 /* now write out any block on a failed drive,
4466                  * or P or Q if they were recomputed
4467                  */
4468                 dev = NULL;
4469                 if (s->failed == 2) {
4470                         dev = &sh->dev[s->failed_num[1]];
4471                         s->locked++;
4472                         set_bit(R5_LOCKED, &dev->flags);
4473                         set_bit(R5_Wantwrite, &dev->flags);
4474                 }
4475                 if (s->failed >= 1) {
4476                         dev = &sh->dev[s->failed_num[0]];
4477                         s->locked++;
4478                         set_bit(R5_LOCKED, &dev->flags);
4479                         set_bit(R5_Wantwrite, &dev->flags);
4480                 }
4481                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4482                         dev = &sh->dev[pd_idx];
4483                         s->locked++;
4484                         set_bit(R5_LOCKED, &dev->flags);
4485                         set_bit(R5_Wantwrite, &dev->flags);
4486                 }
4487                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4488                         dev = &sh->dev[qd_idx];
4489                         s->locked++;
4490                         set_bit(R5_LOCKED, &dev->flags);
4491                         set_bit(R5_Wantwrite, &dev->flags);
4492                 }
4493                 if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),
4494                               "%s: disk%td not up to date\n",
4495                               mdname(conf->mddev),
4496                               dev - (struct r5dev *) &sh->dev)) {
4497                         clear_bit(R5_LOCKED, &dev->flags);
4498                         clear_bit(R5_Wantwrite, &dev->flags);
4499                         s->locked--;
4500                 }
4501                 clear_bit(STRIPE_DEGRADED, &sh->state);
4502
4503                 set_bit(STRIPE_INSYNC, &sh->state);
4504                 break;
4505         case check_state_run:
4506         case check_state_run_q:
4507         case check_state_run_pq:
4508                 break; /* we will be called again upon completion */
4509         case check_state_check_result:
4510                 sh->check_state = check_state_idle;
4511
4512                 /* handle a successful check operation, if parity is correct
4513                  * we are done.  Otherwise update the mismatch count and repair
4514                  * parity if !MD_RECOVERY_CHECK
4515                  */
4516                 if (sh->ops.zero_sum_result == 0) {
4517                         /* both parities are correct */
4518                         if (!s->failed)
4519                                 set_bit(STRIPE_INSYNC, &sh->state);
4520                         else {
4521                                 /* in contrast to the raid5 case we can validate
4522                                  * parity, but still have a failure to write
4523                                  * back
4524                                  */
4525                                 sh->check_state = check_state_compute_result;
4526                                 /* Returning at this point means that we may go
4527                                  * off and bring p and/or q uptodate again so
4528                                  * we make sure to check zero_sum_result again
4529                                  * to verify if p or q need writeback
4530                                  */
4531                         }
4532                 } else {
4533                         atomic64_add(RAID5_STRIPE_SECTORS(conf), &conf->mddev->resync_mismatches);
4534                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4535                                 /* don't try to repair!! */
4536                                 set_bit(STRIPE_INSYNC, &sh->state);
4537                                 pr_warn_ratelimited("%s: mismatch sector in range "
4538                                                     "%llu-%llu\n", mdname(conf->mddev),
4539                                                     (unsigned long long) sh->sector,
4540                                                     (unsigned long long) sh->sector +
4541                                                     RAID5_STRIPE_SECTORS(conf));
4542                         } else {
4543                                 int *target = &sh->ops.target;
4544
4545                                 sh->ops.target = -1;
4546                                 sh->ops.target2 = -1;
4547                                 sh->check_state = check_state_compute_run;
4548                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4549                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4550                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4551                                         set_bit(R5_Wantcompute,
4552                                                 &sh->dev[pd_idx].flags);
4553                                         *target = pd_idx;
4554                                         target = &sh->ops.target2;
4555                                         s->uptodate++;
4556                                 }
4557                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4558                                         set_bit(R5_Wantcompute,
4559                                                 &sh->dev[qd_idx].flags);
4560                                         *target = qd_idx;
4561                                         s->uptodate++;
4562                                 }
4563                         }
4564                 }
4565                 break;
4566         case check_state_compute_run:
4567                 break;
4568         default:
4569                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4570                         __func__, sh->check_state,
4571                         (unsigned long long) sh->sector);
4572                 BUG();
4573         }
4574 }
4575
4576 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4577 {
4578         int i;
4579
4580         /* We have read all the blocks in this stripe and now we need to
4581          * copy some of them into a target stripe for expand.
4582          */
4583         struct dma_async_tx_descriptor *tx = NULL;
4584         BUG_ON(sh->batch_head);
4585         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4586         for (i = 0; i < sh->disks; i++)
4587                 if (i != sh->pd_idx && i != sh->qd_idx) {
4588                         int dd_idx, j;
4589                         struct stripe_head *sh2;
4590                         struct async_submit_ctl submit;
4591
4592                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4593                         sector_t s = raid5_compute_sector(conf, bn, 0,
4594                                                           &dd_idx, NULL);
4595                         sh2 = raid5_get_active_stripe(conf, NULL, s,
4596                                 R5_GAS_NOBLOCK | R5_GAS_NOQUIESCE);
4597                         if (sh2 == NULL)
4598                                 /* so far only the early blocks of this stripe
4599                                  * have been requested.  When later blocks
4600                                  * get requested, we will try again
4601                                  */
4602                                 continue;
4603                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4604                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4605                                 /* must have already done this block */
4606                                 raid5_release_stripe(sh2);
4607                                 continue;
4608                         }
4609
4610                         /* place all the copies on one channel */
4611                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4612                         tx = async_memcpy(sh2->dev[dd_idx].page,
4613                                           sh->dev[i].page, sh2->dev[dd_idx].offset,
4614                                           sh->dev[i].offset, RAID5_STRIPE_SIZE(conf),
4615                                           &submit);
4616
4617                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4618                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4619                         for (j = 0; j < conf->raid_disks; j++)
4620                                 if (j != sh2->pd_idx &&
4621                                     j != sh2->qd_idx &&
4622                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4623                                         break;
4624                         if (j == conf->raid_disks) {
4625                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4626                                 set_bit(STRIPE_HANDLE, &sh2->state);
4627                         }
4628                         raid5_release_stripe(sh2);
4629
4630                 }
4631         /* done submitting copies, wait for them to complete */
4632         async_tx_quiesce(&tx);
4633 }
4634
4635 /*
4636  * handle_stripe - do things to a stripe.
4637  *
4638  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4639  * state of various bits to see what needs to be done.
4640  * Possible results:
4641  *    return some read requests which now have data
4642  *    return some write requests which are safely on storage
4643  *    schedule a read on some buffers
4644  *    schedule a write of some buffers
4645  *    return confirmation of parity correctness
4646  *
4647  */
4648
4649 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4650 {
4651         struct r5conf *conf = sh->raid_conf;
4652         int disks = sh->disks;
4653         struct r5dev *dev;
4654         int i;
4655         int do_recovery = 0;
4656
4657         memset(s, 0, sizeof(*s));
4658
4659         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4660         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4661         s->failed_num[0] = -1;
4662         s->failed_num[1] = -1;
4663         s->log_failed = r5l_log_disk_error(conf);
4664
4665         /* Now to look around and see what can be done */
4666         for (i=disks; i--; ) {
4667                 struct md_rdev *rdev;
4668                 int is_bad = 0;
4669
4670                 dev = &sh->dev[i];
4671
4672                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4673                          i, dev->flags,
4674                          dev->toread, dev->towrite, dev->written);
4675                 /* maybe we can reply to a read
4676                  *
4677                  * new wantfill requests are only permitted while
4678                  * ops_complete_biofill is guaranteed to be inactive
4679                  */
4680                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4681                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4682                         set_bit(R5_Wantfill, &dev->flags);
4683
4684                 /* now count some things */
4685                 if (test_bit(R5_LOCKED, &dev->flags))
4686                         s->locked++;
4687                 if (test_bit(R5_UPTODATE, &dev->flags))
4688                         s->uptodate++;
4689                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4690                         s->compute++;
4691                         BUG_ON(s->compute > 2);
4692                 }
4693
4694                 if (test_bit(R5_Wantfill, &dev->flags))
4695                         s->to_fill++;
4696                 else if (dev->toread)
4697                         s->to_read++;
4698                 if (dev->towrite) {
4699                         s->to_write++;
4700                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4701                                 s->non_overwrite++;
4702                 }
4703                 if (dev->written)
4704                         s->written++;
4705                 /* Prefer to use the replacement for reads, but only
4706                  * if it is recovered enough and has no bad blocks.
4707                  */
4708                 rdev = conf->disks[i].replacement;
4709                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4710                     rdev->recovery_offset >= sh->sector + RAID5_STRIPE_SECTORS(conf) &&
4711                     !rdev_has_badblock(rdev, sh->sector,
4712                                        RAID5_STRIPE_SECTORS(conf)))
4713                         set_bit(R5_ReadRepl, &dev->flags);
4714                 else {
4715                         if (rdev && !test_bit(Faulty, &rdev->flags))
4716                                 set_bit(R5_NeedReplace, &dev->flags);
4717                         else
4718                                 clear_bit(R5_NeedReplace, &dev->flags);
4719                         rdev = conf->disks[i].rdev;
4720                         clear_bit(R5_ReadRepl, &dev->flags);
4721                 }
4722                 if (rdev && test_bit(Faulty, &rdev->flags))
4723                         rdev = NULL;
4724                 if (rdev) {
4725                         is_bad = rdev_has_badblock(rdev, sh->sector,
4726                                                    RAID5_STRIPE_SECTORS(conf));
4727                         if (s->blocked_rdev == NULL) {
4728                                 if (is_bad < 0)
4729                                         set_bit(BlockedBadBlocks, &rdev->flags);
4730                                 if (rdev_blocked(rdev)) {
4731                                         s->blocked_rdev = rdev;
4732                                         atomic_inc(&rdev->nr_pending);
4733                                 }
4734                         }
4735                 }
4736                 clear_bit(R5_Insync, &dev->flags);
4737                 if (!rdev)
4738                         /* Not in-sync */;
4739                 else if (is_bad) {
4740                         /* also not in-sync */
4741                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4742                             test_bit(R5_UPTODATE, &dev->flags)) {
4743                                 /* treat as in-sync, but with a read error
4744                                  * which we can now try to correct
4745                                  */
4746                                 set_bit(R5_Insync, &dev->flags);
4747                                 set_bit(R5_ReadError, &dev->flags);
4748                         }
4749                 } else if (test_bit(In_sync, &rdev->flags))
4750                         set_bit(R5_Insync, &dev->flags);
4751                 else if (sh->sector + RAID5_STRIPE_SECTORS(conf) <= rdev->recovery_offset)
4752                         /* in sync if before recovery_offset */
4753                         set_bit(R5_Insync, &dev->flags);
4754                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4755                          test_bit(R5_Expanded, &dev->flags))
4756                         /* If we've reshaped into here, we assume it is Insync.
4757                          * We will shortly update recovery_offset to make
4758                          * it official.
4759                          */
4760                         set_bit(R5_Insync, &dev->flags);
4761
4762                 if (test_bit(R5_WriteError, &dev->flags)) {
4763                         /* This flag does not apply to '.replacement'
4764                          * only to .rdev, so make sure to check that*/
4765                         struct md_rdev *rdev2 = conf->disks[i].rdev;
4766
4767                         if (rdev2 == rdev)
4768                                 clear_bit(R5_Insync, &dev->flags);
4769                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4770                                 s->handle_bad_blocks = 1;
4771                                 atomic_inc(&rdev2->nr_pending);
4772                         } else
4773                                 clear_bit(R5_WriteError, &dev->flags);
4774                 }
4775                 if (test_bit(R5_MadeGood, &dev->flags)) {
4776                         /* This flag does not apply to '.replacement'
4777                          * only to .rdev, so make sure to check that*/
4778                         struct md_rdev *rdev2 = conf->disks[i].rdev;
4779
4780                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4781                                 s->handle_bad_blocks = 1;
4782                                 atomic_inc(&rdev2->nr_pending);
4783                         } else
4784                                 clear_bit(R5_MadeGood, &dev->flags);
4785                 }
4786                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4787                         struct md_rdev *rdev2 = conf->disks[i].replacement;
4788
4789                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4790                                 s->handle_bad_blocks = 1;
4791                                 atomic_inc(&rdev2->nr_pending);
4792                         } else
4793                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4794                 }
4795                 if (!test_bit(R5_Insync, &dev->flags)) {
4796                         /* The ReadError flag will just be confusing now */
4797                         clear_bit(R5_ReadError, &dev->flags);
4798                         clear_bit(R5_ReWrite, &dev->flags);
4799                 }
4800                 if (test_bit(R5_ReadError, &dev->flags))
4801                         clear_bit(R5_Insync, &dev->flags);
4802                 if (!test_bit(R5_Insync, &dev->flags)) {
4803                         if (s->failed < 2)
4804                                 s->failed_num[s->failed] = i;
4805                         s->failed++;
4806                         if (rdev && !test_bit(Faulty, &rdev->flags))
4807                                 do_recovery = 1;
4808                         else if (!rdev) {
4809                                 rdev = conf->disks[i].replacement;
4810                                 if (rdev && !test_bit(Faulty, &rdev->flags))
4811                                         do_recovery = 1;
4812                         }
4813                 }
4814
4815                 if (test_bit(R5_InJournal, &dev->flags))
4816                         s->injournal++;
4817                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4818                         s->just_cached++;
4819         }
4820         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4821                 /* If there is a failed device being replaced,
4822                  *     we must be recovering.
4823                  * else if we are after recovery_cp, we must be syncing
4824                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4825                  * else we can only be replacing
4826                  * sync and recovery both need to read all devices, and so
4827                  * use the same flag.
4828                  */
4829                 if (do_recovery ||
4830                     sh->sector >= conf->mddev->recovery_cp ||
4831                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4832                         s->syncing = 1;
4833                 else
4834                         s->replacing = 1;
4835         }
4836 }
4837
4838 /*
4839  * Return '1' if this is a member of batch, or '0' if it is a lone stripe or
4840  * a head which can now be handled.
4841  */
4842 static int clear_batch_ready(struct stripe_head *sh)
4843 {
4844         struct stripe_head *tmp;
4845         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4846                 return (sh->batch_head && sh->batch_head != sh);
4847         spin_lock(&sh->stripe_lock);
4848         if (!sh->batch_head) {
4849                 spin_unlock(&sh->stripe_lock);
4850                 return 0;
4851         }
4852
4853         /*
4854          * this stripe could be added to a batch list before we check
4855          * BATCH_READY, skips it
4856          */
4857         if (sh->batch_head != sh) {
4858                 spin_unlock(&sh->stripe_lock);
4859                 return 1;
4860         }
4861         spin_lock(&sh->batch_lock);
4862         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4863                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4864         spin_unlock(&sh->batch_lock);
4865         spin_unlock(&sh->stripe_lock);
4866
4867         /*
4868          * BATCH_READY is cleared, no new stripes can be added.
4869          * batch_list can be accessed without lock
4870          */
4871         return 0;
4872 }
4873
4874 static void break_stripe_batch_list(struct stripe_head *head_sh,
4875                                     unsigned long handle_flags)
4876 {
4877         struct stripe_head *sh, *next;
4878         int i;
4879
4880         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4881
4882                 list_del_init(&sh->batch_list);
4883
4884                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4885                                           (1 << STRIPE_SYNCING) |
4886                                           (1 << STRIPE_REPLACED) |
4887                                           (1 << STRIPE_DELAYED) |
4888                                           (1 << STRIPE_BIT_DELAY) |
4889                                           (1 << STRIPE_FULL_WRITE) |
4890                                           (1 << STRIPE_BIOFILL_RUN) |
4891                                           (1 << STRIPE_COMPUTE_RUN)  |
4892                                           (1 << STRIPE_DISCARD) |
4893                                           (1 << STRIPE_BATCH_READY) |
4894                                           (1 << STRIPE_BATCH_ERR) |
4895                                           (1 << STRIPE_BITMAP_PENDING)),
4896                         "stripe state: %lx\n", sh->state);
4897                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4898                                               (1 << STRIPE_REPLACED)),
4899                         "head stripe state: %lx\n", head_sh->state);
4900
4901                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4902                                             (1 << STRIPE_PREREAD_ACTIVE) |
4903                                             (1 << STRIPE_DEGRADED) |
4904                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4905                               head_sh->state & (1 << STRIPE_INSYNC));
4906
4907                 sh->check_state = head_sh->check_state;
4908                 sh->reconstruct_state = head_sh->reconstruct_state;
4909                 spin_lock_irq(&sh->stripe_lock);
4910                 sh->batch_head = NULL;
4911                 spin_unlock_irq(&sh->stripe_lock);
4912                 for (i = 0; i < sh->disks; i++) {
4913                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4914                                 wake_up_bit(&sh->dev[i].flags, R5_Overlap);
4915                         sh->dev[i].flags = head_sh->dev[i].flags &
4916                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4917                 }
4918                 if (handle_flags == 0 ||
4919                     sh->state & handle_flags)
4920                         set_bit(STRIPE_HANDLE, &sh->state);
4921                 raid5_release_stripe(sh);
4922         }
4923         spin_lock_irq(&head_sh->stripe_lock);
4924         head_sh->batch_head = NULL;
4925         spin_unlock_irq(&head_sh->stripe_lock);
4926         for (i = 0; i < head_sh->disks; i++)
4927                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4928                         wake_up_bit(&head_sh->dev[i].flags, R5_Overlap);
4929         if (head_sh->state & handle_flags)
4930                 set_bit(STRIPE_HANDLE, &head_sh->state);
4931 }
4932
4933 static void handle_stripe(struct stripe_head *sh)
4934 {
4935         struct stripe_head_state s;
4936         struct r5conf *conf = sh->raid_conf;
4937         int i;
4938         int prexor;
4939         int disks = sh->disks;
4940         struct r5dev *pdev, *qdev;
4941
4942         clear_bit(STRIPE_HANDLE, &sh->state);
4943
4944         /*
4945          * handle_stripe should not continue handle the batched stripe, only
4946          * the head of batch list or lone stripe can continue. Otherwise we
4947          * could see break_stripe_batch_list warns about the STRIPE_ACTIVE
4948          * is set for the batched stripe.
4949          */
4950         if (clear_batch_ready(sh))
4951                 return;
4952
4953         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4954                 /* already being handled, ensure it gets handled
4955                  * again when current action finishes */
4956                 set_bit(STRIPE_HANDLE, &sh->state);
4957                 return;
4958         }
4959
4960         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4961                 break_stripe_batch_list(sh, 0);
4962
4963         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4964                 spin_lock(&sh->stripe_lock);
4965                 /*
4966                  * Cannot process 'sync' concurrently with 'discard'.
4967                  * Flush data in r5cache before 'sync'.
4968                  */
4969                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4970                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4971                     !test_bit(STRIPE_DISCARD, &sh->state) &&
4972                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4973                         set_bit(STRIPE_SYNCING, &sh->state);
4974                         clear_bit(STRIPE_INSYNC, &sh->state);
4975                         clear_bit(STRIPE_REPLACED, &sh->state);
4976                 }
4977                 spin_unlock(&sh->stripe_lock);
4978         }
4979         clear_bit(STRIPE_DELAYED, &sh->state);
4980
4981         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4982                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4983                (unsigned long long)sh->sector, sh->state,
4984                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4985                sh->check_state, sh->reconstruct_state);
4986
4987         analyse_stripe(sh, &s);
4988
4989         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4990                 goto finish;
4991
4992         if (s.handle_bad_blocks ||
4993             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4994                 set_bit(STRIPE_HANDLE, &sh->state);
4995                 goto finish;
4996         }
4997
4998         if (unlikely(s.blocked_rdev)) {
4999                 if (s.syncing || s.expanding || s.expanded ||
5000                     s.replacing || s.to_write || s.written) {
5001                         set_bit(STRIPE_HANDLE, &sh->state);
5002                         goto finish;
5003                 }
5004                 /* There is nothing for the blocked_rdev to block */
5005                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
5006                 s.blocked_rdev = NULL;
5007         }
5008
5009         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
5010                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
5011                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
5012         }
5013
5014         pr_debug("locked=%d uptodate=%d to_read=%d"
5015                " to_write=%d failed=%d failed_num=%d,%d\n",
5016                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
5017                s.failed_num[0], s.failed_num[1]);
5018         /*
5019          * check if the array has lost more than max_degraded devices and,
5020          * if so, some requests might need to be failed.
5021          *
5022          * When journal device failed (log_failed), we will only process
5023          * the stripe if there is data need write to raid disks
5024          */
5025         if (s.failed > conf->max_degraded ||
5026             (s.log_failed && s.injournal == 0)) {
5027                 sh->check_state = 0;
5028                 sh->reconstruct_state = 0;
5029                 break_stripe_batch_list(sh, 0);
5030                 if (s.to_read+s.to_write+s.written)
5031                         handle_failed_stripe(conf, sh, &s, disks);
5032                 if (s.syncing + s.replacing)
5033                         handle_failed_sync(conf, sh, &s);
5034         }
5035
5036         /* Now we check to see if any write operations have recently
5037          * completed
5038          */
5039         prexor = 0;
5040         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
5041                 prexor = 1;
5042         if (sh->reconstruct_state == reconstruct_state_drain_result ||
5043             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
5044                 sh->reconstruct_state = reconstruct_state_idle;
5045
5046                 /* All the 'written' buffers and the parity block are ready to
5047                  * be written back to disk
5048                  */
5049                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
5050                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
5051                 BUG_ON(sh->qd_idx >= 0 &&
5052                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
5053                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
5054                 for (i = disks; i--; ) {
5055                         struct r5dev *dev = &sh->dev[i];
5056                         if (test_bit(R5_LOCKED, &dev->flags) &&
5057                                 (i == sh->pd_idx || i == sh->qd_idx ||
5058                                  dev->written || test_bit(R5_InJournal,
5059                                                           &dev->flags))) {
5060                                 pr_debug("Writing block %d\n", i);
5061                                 set_bit(R5_Wantwrite, &dev->flags);
5062                                 if (prexor)
5063                                         continue;
5064                                 if (s.failed > 1)
5065                                         continue;
5066                                 if (!test_bit(R5_Insync, &dev->flags) ||
5067                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
5068                                      s.failed == 0))
5069                                         set_bit(STRIPE_INSYNC, &sh->state);
5070                         }
5071                 }
5072                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5073                         s.dec_preread_active = 1;
5074         }
5075
5076         /*
5077          * might be able to return some write requests if the parity blocks
5078          * are safe, or on a failed drive
5079          */
5080         pdev = &sh->dev[sh->pd_idx];
5081         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
5082                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
5083         qdev = &sh->dev[sh->qd_idx];
5084         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
5085                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
5086                 || conf->level < 6;
5087
5088         if (s.written &&
5089             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
5090                              && !test_bit(R5_LOCKED, &pdev->flags)
5091                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
5092                                  test_bit(R5_Discard, &pdev->flags))))) &&
5093             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
5094                              && !test_bit(R5_LOCKED, &qdev->flags)
5095                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
5096                                  test_bit(R5_Discard, &qdev->flags))))))
5097                 handle_stripe_clean_event(conf, sh, disks);
5098
5099         if (s.just_cached)
5100                 r5c_handle_cached_data_endio(conf, sh, disks);
5101         log_stripe_write_finished(sh);
5102
5103         /* Now we might consider reading some blocks, either to check/generate
5104          * parity, or to satisfy requests
5105          * or to load a block that is being partially written.
5106          */
5107         if (s.to_read || s.non_overwrite
5108             || (s.to_write && s.failed)
5109             || (s.syncing && (s.uptodate + s.compute < disks))
5110             || s.replacing
5111             || s.expanding)
5112                 handle_stripe_fill(sh, &s, disks);
5113
5114         /*
5115          * When the stripe finishes full journal write cycle (write to journal
5116          * and raid disk), this is the clean up procedure so it is ready for
5117          * next operation.
5118          */
5119         r5c_finish_stripe_write_out(conf, sh, &s);
5120
5121         /*
5122          * Now to consider new write requests, cache write back and what else,
5123          * if anything should be read.  We do not handle new writes when:
5124          * 1/ A 'write' operation (copy+xor) is already in flight.
5125          * 2/ A 'check' operation is in flight, as it may clobber the parity
5126          *    block.
5127          * 3/ A r5c cache log write is in flight.
5128          */
5129
5130         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
5131                 if (!r5c_is_writeback(conf->log)) {
5132                         if (s.to_write)
5133                                 handle_stripe_dirtying(conf, sh, &s, disks);
5134                 } else { /* write back cache */
5135                         int ret = 0;
5136
5137                         /* First, try handle writes in caching phase */
5138                         if (s.to_write)
5139                                 ret = r5c_try_caching_write(conf, sh, &s,
5140                                                             disks);
5141                         /*
5142                          * If caching phase failed: ret == -EAGAIN
5143                          *    OR
5144                          * stripe under reclaim: !caching && injournal
5145                          *
5146                          * fall back to handle_stripe_dirtying()
5147                          */
5148                         if (ret == -EAGAIN ||
5149                             /* stripe under reclaim: !caching && injournal */
5150                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
5151                              s.injournal > 0)) {
5152                                 ret = handle_stripe_dirtying(conf, sh, &s,
5153                                                              disks);
5154                                 if (ret == -EAGAIN)
5155                                         goto finish;
5156                         }
5157                 }
5158         }
5159
5160         /* maybe we need to check and possibly fix the parity for this stripe
5161          * Any reads will already have been scheduled, so we just see if enough
5162          * data is available.  The parity check is held off while parity
5163          * dependent operations are in flight.
5164          */
5165         if (sh->check_state ||
5166             (s.syncing && s.locked == 0 &&
5167              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5168              !test_bit(STRIPE_INSYNC, &sh->state))) {
5169                 if (conf->level == 6)
5170                         handle_parity_checks6(conf, sh, &s, disks);
5171                 else
5172                         handle_parity_checks5(conf, sh, &s, disks);
5173         }
5174
5175         if ((s.replacing || s.syncing) && s.locked == 0
5176             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
5177             && !test_bit(STRIPE_REPLACED, &sh->state)) {
5178                 /* Write out to replacement devices where possible */
5179                 for (i = 0; i < conf->raid_disks; i++)
5180                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
5181                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
5182                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
5183                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
5184                                 s.locked++;
5185                         }
5186                 if (s.replacing)
5187                         set_bit(STRIPE_INSYNC, &sh->state);
5188                 set_bit(STRIPE_REPLACED, &sh->state);
5189         }
5190         if ((s.syncing || s.replacing) && s.locked == 0 &&
5191             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
5192             test_bit(STRIPE_INSYNC, &sh->state)) {
5193                 md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5194                 clear_bit(STRIPE_SYNCING, &sh->state);
5195                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
5196                         wake_up_bit(&sh->dev[sh->pd_idx].flags, R5_Overlap);
5197         }
5198
5199         /* If the failed drives are just a ReadError, then we might need
5200          * to progress the repair/check process
5201          */
5202         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
5203                 for (i = 0; i < s.failed; i++) {
5204                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
5205                         if (test_bit(R5_ReadError, &dev->flags)
5206                             && !test_bit(R5_LOCKED, &dev->flags)
5207                             && test_bit(R5_UPTODATE, &dev->flags)
5208                                 ) {
5209                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
5210                                         set_bit(R5_Wantwrite, &dev->flags);
5211                                         set_bit(R5_ReWrite, &dev->flags);
5212                                 } else
5213                                         /* let's read it back */
5214                                         set_bit(R5_Wantread, &dev->flags);
5215                                 set_bit(R5_LOCKED, &dev->flags);
5216                                 s.locked++;
5217                         }
5218                 }
5219
5220         /* Finish reconstruct operations initiated by the expansion process */
5221         if (sh->reconstruct_state == reconstruct_state_result) {
5222                 struct stripe_head *sh_src
5223                         = raid5_get_active_stripe(conf, NULL, sh->sector,
5224                                         R5_GAS_PREVIOUS | R5_GAS_NOBLOCK |
5225                                         R5_GAS_NOQUIESCE);
5226                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
5227                         /* sh cannot be written until sh_src has been read.
5228                          * so arrange for sh to be delayed a little
5229                          */
5230                         set_bit(STRIPE_DELAYED, &sh->state);
5231                         set_bit(STRIPE_HANDLE, &sh->state);
5232                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
5233                                               &sh_src->state))
5234                                 atomic_inc(&conf->preread_active_stripes);
5235                         raid5_release_stripe(sh_src);
5236                         goto finish;
5237                 }
5238                 if (sh_src)
5239                         raid5_release_stripe(sh_src);
5240
5241                 sh->reconstruct_state = reconstruct_state_idle;
5242                 clear_bit(STRIPE_EXPANDING, &sh->state);
5243                 for (i = conf->raid_disks; i--; ) {
5244                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
5245                         set_bit(R5_LOCKED, &sh->dev[i].flags);
5246                         s.locked++;
5247                 }
5248         }
5249
5250         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
5251             !sh->reconstruct_state) {
5252                 /* Need to write out all blocks after computing parity */
5253                 sh->disks = conf->raid_disks;
5254                 stripe_set_idx(sh->sector, conf, 0, sh);
5255                 schedule_reconstruction(sh, &s, 1, 1);
5256         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
5257                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
5258                 atomic_dec(&conf->reshape_stripes);
5259                 wake_up(&conf->wait_for_reshape);
5260                 md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf), 1);
5261         }
5262
5263         if (s.expanding && s.locked == 0 &&
5264             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
5265                 handle_stripe_expansion(conf, sh);
5266
5267 finish:
5268         /* wait for this device to become unblocked */
5269         if (unlikely(s.blocked_rdev)) {
5270                 if (conf->mddev->external)
5271                         md_wait_for_blocked_rdev(s.blocked_rdev,
5272                                                  conf->mddev);
5273                 else
5274                         /* Internal metadata will immediately
5275                          * be written by raid5d, so we don't
5276                          * need to wait here.
5277                          */
5278                         rdev_dec_pending(s.blocked_rdev,
5279                                          conf->mddev);
5280         }
5281
5282         if (s.handle_bad_blocks)
5283                 for (i = disks; i--; ) {
5284                         struct md_rdev *rdev;
5285                         struct r5dev *dev = &sh->dev[i];
5286                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
5287                                 /* We own a safe reference to the rdev */
5288                                 rdev = conf->disks[i].rdev;
5289                                 if (!rdev_set_badblocks(rdev, sh->sector,
5290                                                         RAID5_STRIPE_SECTORS(conf), 0))
5291                                         md_error(conf->mddev, rdev);
5292                                 rdev_dec_pending(rdev, conf->mddev);
5293                         }
5294                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5295                                 rdev = conf->disks[i].rdev;
5296                                 rdev_clear_badblocks(rdev, sh->sector,
5297                                                      RAID5_STRIPE_SECTORS(conf), 0);
5298                                 rdev_dec_pending(rdev, conf->mddev);
5299                         }
5300                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5301                                 rdev = conf->disks[i].replacement;
5302                                 if (!rdev)
5303                                         /* rdev have been moved down */
5304                                         rdev = conf->disks[i].rdev;
5305                                 rdev_clear_badblocks(rdev, sh->sector,
5306                                                      RAID5_STRIPE_SECTORS(conf), 0);
5307                                 rdev_dec_pending(rdev, conf->mddev);
5308                         }
5309                 }
5310
5311         if (s.ops_request)
5312                 raid_run_ops(sh, s.ops_request);
5313
5314         ops_run_io(sh, &s);
5315
5316         if (s.dec_preread_active) {
5317                 /* We delay this until after ops_run_io so that if make_request
5318                  * is waiting on a flush, it won't continue until the writes
5319                  * have actually been submitted.
5320                  */
5321                 atomic_dec(&conf->preread_active_stripes);
5322                 if (atomic_read(&conf->preread_active_stripes) <
5323                     IO_THRESHOLD)
5324                         md_wakeup_thread(conf->mddev->thread);
5325         }
5326
5327         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5328 }
5329
5330 static void raid5_activate_delayed(struct r5conf *conf)
5331         __must_hold(&conf->device_lock)
5332 {
5333         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5334                 while (!list_empty(&conf->delayed_list)) {
5335                         struct list_head *l = conf->delayed_list.next;
5336                         struct stripe_head *sh;
5337                         sh = list_entry(l, struct stripe_head, lru);
5338                         list_del_init(l);
5339                         clear_bit(STRIPE_DELAYED, &sh->state);
5340                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5341                                 atomic_inc(&conf->preread_active_stripes);
5342                         list_add_tail(&sh->lru, &conf->hold_list);
5343                         raid5_wakeup_stripe_thread(sh);
5344                 }
5345         }
5346 }
5347
5348 static void activate_bit_delay(struct r5conf *conf,
5349                 struct list_head *temp_inactive_list)
5350         __must_hold(&conf->device_lock)
5351 {
5352         struct list_head head;
5353         list_add(&head, &conf->bitmap_list);
5354         list_del_init(&conf->bitmap_list);
5355         while (!list_empty(&head)) {
5356                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5357                 int hash;
5358                 list_del_init(&sh->lru);
5359                 atomic_inc(&sh->count);
5360                 hash = sh->hash_lock_index;
5361                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5362         }
5363 }
5364
5365 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5366 {
5367         struct r5conf *conf = mddev->private;
5368         sector_t sector = bio->bi_iter.bi_sector;
5369         unsigned int chunk_sectors;
5370         unsigned int bio_sectors = bio_sectors(bio);
5371
5372         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5373         return  chunk_sectors >=
5374                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5375 }
5376
5377 /*
5378  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5379  *  later sampled by raid5d.
5380  */
5381 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5382 {
5383         unsigned long flags;
5384
5385         spin_lock_irqsave(&conf->device_lock, flags);
5386
5387         bi->bi_next = conf->retry_read_aligned_list;
5388         conf->retry_read_aligned_list = bi;
5389
5390         spin_unlock_irqrestore(&conf->device_lock, flags);
5391         md_wakeup_thread(conf->mddev->thread);
5392 }
5393
5394 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5395                                          unsigned int *offset)
5396 {
5397         struct bio *bi;
5398
5399         bi = conf->retry_read_aligned;
5400         if (bi) {
5401                 *offset = conf->retry_read_offset;
5402                 conf->retry_read_aligned = NULL;
5403                 return bi;
5404         }
5405         bi = conf->retry_read_aligned_list;
5406         if(bi) {
5407                 conf->retry_read_aligned_list = bi->bi_next;
5408                 bi->bi_next = NULL;
5409                 *offset = 0;
5410         }
5411
5412         return bi;
5413 }
5414
5415 /*
5416  *  The "raid5_align_endio" should check if the read succeeded and if it
5417  *  did, call bio_endio on the original bio (having bio_put the new bio
5418  *  first).
5419  *  If the read failed..
5420  */
5421 static void raid5_align_endio(struct bio *bi)
5422 {
5423         struct bio *raid_bi = bi->bi_private;
5424         struct md_rdev *rdev = (void *)raid_bi->bi_next;
5425         struct mddev *mddev = rdev->mddev;
5426         struct r5conf *conf = mddev->private;
5427         blk_status_t error = bi->bi_status;
5428
5429         bio_put(bi);
5430         raid_bi->bi_next = NULL;
5431         rdev_dec_pending(rdev, conf->mddev);
5432
5433         if (!error) {
5434                 bio_endio(raid_bi);
5435                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5436                         wake_up(&conf->wait_for_quiescent);
5437                 return;
5438         }
5439
5440         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5441
5442         add_bio_to_retry(raid_bi, conf);
5443 }
5444
5445 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5446 {
5447         struct r5conf *conf = mddev->private;
5448         struct bio *align_bio;
5449         struct md_rdev *rdev;
5450         sector_t sector, end_sector;
5451         int dd_idx;
5452         bool did_inc;
5453
5454         if (!in_chunk_boundary(mddev, raid_bio)) {
5455                 pr_debug("%s: non aligned\n", __func__);
5456                 return 0;
5457         }
5458
5459         sector = raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector, 0,
5460                                       &dd_idx, NULL);
5461         end_sector = sector + bio_sectors(raid_bio);
5462
5463         if (r5c_big_stripe_cached(conf, sector))
5464                 return 0;
5465
5466         rdev = conf->disks[dd_idx].replacement;
5467         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5468             rdev->recovery_offset < end_sector) {
5469                 rdev = conf->disks[dd_idx].rdev;
5470                 if (!rdev)
5471                         return 0;
5472                 if (test_bit(Faulty, &rdev->flags) ||
5473                     !(test_bit(In_sync, &rdev->flags) ||
5474                       rdev->recovery_offset >= end_sector))
5475                         return 0;
5476         }
5477
5478         atomic_inc(&rdev->nr_pending);
5479
5480         if (rdev_has_badblock(rdev, sector, bio_sectors(raid_bio))) {
5481                 rdev_dec_pending(rdev, mddev);
5482                 return 0;
5483         }
5484
5485         md_account_bio(mddev, &raid_bio);
5486         raid_bio->bi_next = (void *)rdev;
5487
5488         align_bio = bio_alloc_clone(rdev->bdev, raid_bio, GFP_NOIO,
5489                                     &mddev->bio_set);
5490         align_bio->bi_end_io = raid5_align_endio;
5491         align_bio->bi_private = raid_bio;
5492         align_bio->bi_iter.bi_sector = sector;
5493
5494         /* No reshape active, so we can trust rdev->data_offset */
5495         align_bio->bi_iter.bi_sector += rdev->data_offset;
5496
5497         did_inc = false;
5498         if (conf->quiesce == 0) {
5499                 atomic_inc(&conf->active_aligned_reads);
5500                 did_inc = true;
5501         }
5502         /* need a memory barrier to detect the race with raid5_quiesce() */
5503         if (!did_inc || smp_load_acquire(&conf->quiesce) != 0) {
5504                 /* quiesce is in progress, so we need to undo io activation and wait
5505                  * for it to finish
5506                  */
5507                 if (did_inc && atomic_dec_and_test(&conf->active_aligned_reads))
5508                         wake_up(&conf->wait_for_quiescent);
5509                 spin_lock_irq(&conf->device_lock);
5510                 wait_event_lock_irq(conf->wait_for_quiescent, conf->quiesce == 0,
5511                                     conf->device_lock);
5512                 atomic_inc(&conf->active_aligned_reads);
5513                 spin_unlock_irq(&conf->device_lock);
5514         }
5515
5516         mddev_trace_remap(mddev, align_bio, raid_bio->bi_iter.bi_sector);
5517         submit_bio_noacct(align_bio);
5518         return 1;
5519 }
5520
5521 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5522 {
5523         struct bio *split;
5524         sector_t sector = raid_bio->bi_iter.bi_sector;
5525         unsigned chunk_sects = mddev->chunk_sectors;
5526         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5527
5528         if (sectors < bio_sectors(raid_bio)) {
5529                 struct r5conf *conf = mddev->private;
5530                 split = bio_split(raid_bio, sectors, GFP_NOIO, &conf->bio_split);
5531                 bio_chain(split, raid_bio);
5532                 submit_bio_noacct(raid_bio);
5533                 raid_bio = split;
5534         }
5535
5536         if (!raid5_read_one_chunk(mddev, raid_bio))
5537                 return raid_bio;
5538
5539         return NULL;
5540 }
5541
5542 /* __get_priority_stripe - get the next stripe to process
5543  *
5544  * Full stripe writes are allowed to pass preread active stripes up until
5545  * the bypass_threshold is exceeded.  In general the bypass_count
5546  * increments when the handle_list is handled before the hold_list; however, it
5547  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5548  * stripe with in flight i/o.  The bypass_count will be reset when the
5549  * head of the hold_list has changed, i.e. the head was promoted to the
5550  * handle_list.
5551  */
5552 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5553         __must_hold(&conf->device_lock)
5554 {
5555         struct stripe_head *sh, *tmp;
5556         struct list_head *handle_list = NULL;
5557         struct r5worker_group *wg;
5558         bool second_try = !r5c_is_writeback(conf->log) &&
5559                 !r5l_log_disk_error(conf);
5560         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5561                 r5l_log_disk_error(conf);
5562
5563 again:
5564         wg = NULL;
5565         sh = NULL;
5566         if (conf->worker_cnt_per_group == 0) {
5567                 handle_list = try_loprio ? &conf->loprio_list :
5568                                         &conf->handle_list;
5569         } else if (group != ANY_GROUP) {
5570                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5571                                 &conf->worker_groups[group].handle_list;
5572                 wg = &conf->worker_groups[group];
5573         } else {
5574                 int i;
5575                 for (i = 0; i < conf->group_cnt; i++) {
5576                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5577                                 &conf->worker_groups[i].handle_list;
5578                         wg = &conf->worker_groups[i];
5579                         if (!list_empty(handle_list))
5580                                 break;
5581                 }
5582         }
5583
5584         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5585                   __func__,
5586                   list_empty(handle_list) ? "empty" : "busy",
5587                   list_empty(&conf->hold_list) ? "empty" : "busy",
5588                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5589
5590         if (!list_empty(handle_list)) {
5591                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5592
5593                 if (list_empty(&conf->hold_list))
5594                         conf->bypass_count = 0;
5595                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5596                         if (conf->hold_list.next == conf->last_hold)
5597                                 conf->bypass_count++;
5598                         else {
5599                                 conf->last_hold = conf->hold_list.next;
5600                                 conf->bypass_count -= conf->bypass_threshold;
5601                                 if (conf->bypass_count < 0)
5602                                         conf->bypass_count = 0;
5603                         }
5604                 }
5605         } else if (!list_empty(&conf->hold_list) &&
5606                    ((conf->bypass_threshold &&
5607                      conf->bypass_count > conf->bypass_threshold) ||
5608                     atomic_read(&conf->pending_full_writes) == 0)) {
5609
5610                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5611                         if (conf->worker_cnt_per_group == 0 ||
5612                             group == ANY_GROUP ||
5613                             !cpu_online(tmp->cpu) ||
5614                             cpu_to_group(tmp->cpu) == group) {
5615                                 sh = tmp;
5616                                 break;
5617                         }
5618                 }
5619
5620                 if (sh) {
5621                         conf->bypass_count -= conf->bypass_threshold;
5622                         if (conf->bypass_count < 0)
5623                                 conf->bypass_count = 0;
5624                 }
5625                 wg = NULL;
5626         }
5627
5628         if (!sh) {
5629                 if (second_try)
5630                         return NULL;
5631                 second_try = true;
5632                 try_loprio = !try_loprio;
5633                 goto again;
5634         }
5635
5636         if (wg) {
5637                 wg->stripes_cnt--;
5638                 sh->group = NULL;
5639         }
5640         list_del_init(&sh->lru);
5641         BUG_ON(atomic_inc_return(&sh->count) != 1);
5642         return sh;
5643 }
5644
5645 struct raid5_plug_cb {
5646         struct blk_plug_cb      cb;
5647         struct list_head        list;
5648         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5649 };
5650
5651 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5652 {
5653         struct raid5_plug_cb *cb = container_of(
5654                 blk_cb, struct raid5_plug_cb, cb);
5655         struct stripe_head *sh;
5656         struct mddev *mddev = cb->cb.data;
5657         struct r5conf *conf = mddev->private;
5658         int cnt = 0;
5659         int hash;
5660
5661         if (cb->list.next && !list_empty(&cb->list)) {
5662                 spin_lock_irq(&conf->device_lock);
5663                 while (!list_empty(&cb->list)) {
5664                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5665                         list_del_init(&sh->lru);
5666                         /*
5667                          * avoid race release_stripe_plug() sees
5668                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5669                          * is still in our list
5670                          */
5671                         smp_mb__before_atomic();
5672                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5673                         /*
5674                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5675                          * case, the count is always > 1 here
5676                          */
5677                         hash = sh->hash_lock_index;
5678                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5679                         cnt++;
5680                 }
5681                 spin_unlock_irq(&conf->device_lock);
5682         }
5683         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5684                                      NR_STRIPE_HASH_LOCKS);
5685         if (!mddev_is_dm(mddev))
5686                 trace_block_unplug(mddev->gendisk->queue, cnt, !from_schedule);
5687         kfree(cb);
5688 }
5689
5690 static void release_stripe_plug(struct mddev *mddev,
5691                                 struct stripe_head *sh)
5692 {
5693         struct blk_plug_cb *blk_cb = blk_check_plugged(
5694                 raid5_unplug, mddev,
5695                 sizeof(struct raid5_plug_cb));
5696         struct raid5_plug_cb *cb;
5697
5698         if (!blk_cb) {
5699                 raid5_release_stripe(sh);
5700                 return;
5701         }
5702
5703         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5704
5705         if (cb->list.next == NULL) {
5706                 int i;
5707                 INIT_LIST_HEAD(&cb->list);
5708                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5709                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5710         }
5711
5712         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5713                 list_add_tail(&sh->lru, &cb->list);
5714         else
5715                 raid5_release_stripe(sh);
5716 }
5717
5718 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5719 {
5720         struct r5conf *conf = mddev->private;
5721         sector_t logical_sector, last_sector;
5722         struct stripe_head *sh;
5723         int stripe_sectors;
5724
5725         /* We need to handle this when io_uring supports discard/trim */
5726         if (WARN_ON_ONCE(bi->bi_opf & REQ_NOWAIT))
5727                 return;
5728
5729         if (mddev->reshape_position != MaxSector)
5730                 /* Skip discard while reshape is happening */
5731                 return;
5732
5733         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
5734         last_sector = bio_end_sector(bi);
5735
5736         bi->bi_next = NULL;
5737
5738         stripe_sectors = conf->chunk_sectors *
5739                 (conf->raid_disks - conf->max_degraded);
5740         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5741                                                stripe_sectors);
5742         sector_div(last_sector, stripe_sectors);
5743
5744         logical_sector *= conf->chunk_sectors;
5745         last_sector *= conf->chunk_sectors;
5746
5747         for (; logical_sector < last_sector;
5748              logical_sector += RAID5_STRIPE_SECTORS(conf)) {
5749                 DEFINE_WAIT(w);
5750                 int d;
5751         again:
5752                 sh = raid5_get_active_stripe(conf, NULL, logical_sector, 0);
5753                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5754                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5755                         raid5_release_stripe(sh);
5756                         wait_on_bit(&sh->dev[sh->pd_idx].flags, R5_Overlap,
5757                                     TASK_UNINTERRUPTIBLE);
5758                         goto again;
5759                 }
5760                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5761                 spin_lock_irq(&sh->stripe_lock);
5762                 for (d = 0; d < conf->raid_disks; d++) {
5763                         if (d == sh->pd_idx || d == sh->qd_idx)
5764                                 continue;
5765                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5766                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5767                                 spin_unlock_irq(&sh->stripe_lock);
5768                                 raid5_release_stripe(sh);
5769                                 wait_on_bit(&sh->dev[d].flags, R5_Overlap,
5770                                             TASK_UNINTERRUPTIBLE);
5771                                 goto again;
5772                         }
5773                 }
5774                 set_bit(STRIPE_DISCARD, &sh->state);
5775                 sh->overwrite_disks = 0;
5776                 for (d = 0; d < conf->raid_disks; d++) {
5777                         if (d == sh->pd_idx || d == sh->qd_idx)
5778                                 continue;
5779                         sh->dev[d].towrite = bi;
5780                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5781                         bio_inc_remaining(bi);
5782                         md_write_inc(mddev, bi);
5783                         sh->overwrite_disks++;
5784                 }
5785                 spin_unlock_irq(&sh->stripe_lock);
5786                 if (conf->mddev->bitmap) {
5787                         for (d = 0; d < conf->raid_disks - conf->max_degraded;
5788                              d++)
5789                                 mddev->bitmap_ops->startwrite(mddev, sh->sector,
5790                                         RAID5_STRIPE_SECTORS(conf), false);
5791                         sh->bm_seq = conf->seq_flush + 1;
5792                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5793                 }
5794
5795                 set_bit(STRIPE_HANDLE, &sh->state);
5796                 clear_bit(STRIPE_DELAYED, &sh->state);
5797                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5798                         atomic_inc(&conf->preread_active_stripes);
5799                 release_stripe_plug(mddev, sh);
5800         }
5801
5802         bio_endio(bi);
5803 }
5804
5805 static bool ahead_of_reshape(struct mddev *mddev, sector_t sector,
5806                              sector_t reshape_sector)
5807 {
5808         return mddev->reshape_backwards ? sector < reshape_sector :
5809                                           sector >= reshape_sector;
5810 }
5811
5812 static bool range_ahead_of_reshape(struct mddev *mddev, sector_t min,
5813                                    sector_t max, sector_t reshape_sector)
5814 {
5815         return mddev->reshape_backwards ? max < reshape_sector :
5816                                           min >= reshape_sector;
5817 }
5818
5819 static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf,
5820                                     struct stripe_head *sh)
5821 {
5822         sector_t max_sector = 0, min_sector = MaxSector;
5823         bool ret = false;
5824         int dd_idx;
5825
5826         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5827                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5828                         continue;
5829
5830                 min_sector = min(min_sector, sh->dev[dd_idx].sector);
5831                 max_sector = max(max_sector, sh->dev[dd_idx].sector);
5832         }
5833
5834         spin_lock_irq(&conf->device_lock);
5835
5836         if (!range_ahead_of_reshape(mddev, min_sector, max_sector,
5837                                      conf->reshape_progress))
5838                 /* mismatch, need to try again */
5839                 ret = true;
5840
5841         spin_unlock_irq(&conf->device_lock);
5842
5843         return ret;
5844 }
5845
5846 static int add_all_stripe_bios(struct r5conf *conf,
5847                 struct stripe_request_ctx *ctx, struct stripe_head *sh,
5848                 struct bio *bi, int forwrite, int previous)
5849 {
5850         int dd_idx;
5851
5852         spin_lock_irq(&sh->stripe_lock);
5853
5854         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5855                 struct r5dev *dev = &sh->dev[dd_idx];
5856
5857                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5858                         continue;
5859
5860                 if (dev->sector < ctx->first_sector ||
5861                     dev->sector >= ctx->last_sector)
5862                         continue;
5863
5864                 if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) {
5865                         set_bit(R5_Overlap, &dev->flags);
5866                         spin_unlock_irq(&sh->stripe_lock);
5867                         raid5_release_stripe(sh);
5868                         /* release batch_last before wait to avoid risk of deadlock */
5869                         if (ctx->batch_last) {
5870                                 raid5_release_stripe(ctx->batch_last);
5871                                 ctx->batch_last = NULL;
5872                         }
5873                         md_wakeup_thread(conf->mddev->thread);
5874                         wait_on_bit(&dev->flags, R5_Overlap, TASK_UNINTERRUPTIBLE);
5875                         return 0;
5876                 }
5877         }
5878
5879         for (dd_idx = 0; dd_idx < sh->disks; dd_idx++) {
5880                 struct r5dev *dev = &sh->dev[dd_idx];
5881
5882                 if (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
5883                         continue;
5884
5885                 if (dev->sector < ctx->first_sector ||
5886                     dev->sector >= ctx->last_sector)
5887                         continue;
5888
5889                 __add_stripe_bio(sh, bi, dd_idx, forwrite, previous);
5890                 clear_bit((dev->sector - ctx->first_sector) >>
5891                           RAID5_STRIPE_SHIFT(conf), ctx->sectors_to_do);
5892         }
5893
5894         spin_unlock_irq(&sh->stripe_lock);
5895         return 1;
5896 }
5897
5898 enum reshape_loc {
5899         LOC_NO_RESHAPE,
5900         LOC_AHEAD_OF_RESHAPE,
5901         LOC_INSIDE_RESHAPE,
5902         LOC_BEHIND_RESHAPE,
5903 };
5904
5905 static enum reshape_loc get_reshape_loc(struct mddev *mddev,
5906                 struct r5conf *conf, sector_t logical_sector)
5907 {
5908         sector_t reshape_progress, reshape_safe;
5909         /*
5910          * Spinlock is needed as reshape_progress may be
5911          * 64bit on a 32bit platform, and so it might be
5912          * possible to see a half-updated value
5913          * Of course reshape_progress could change after
5914          * the lock is dropped, so once we get a reference
5915          * to the stripe that we think it is, we will have
5916          * to check again.
5917          */
5918         spin_lock_irq(&conf->device_lock);
5919         reshape_progress = conf->reshape_progress;
5920         reshape_safe = conf->reshape_safe;
5921         spin_unlock_irq(&conf->device_lock);
5922         if (reshape_progress == MaxSector)
5923                 return LOC_NO_RESHAPE;
5924         if (ahead_of_reshape(mddev, logical_sector, reshape_progress))
5925                 return LOC_AHEAD_OF_RESHAPE;
5926         if (ahead_of_reshape(mddev, logical_sector, reshape_safe))
5927                 return LOC_INSIDE_RESHAPE;
5928         return LOC_BEHIND_RESHAPE;
5929 }
5930
5931 static enum stripe_result make_stripe_request(struct mddev *mddev,
5932                 struct r5conf *conf, struct stripe_request_ctx *ctx,
5933                 sector_t logical_sector, struct bio *bi)
5934 {
5935         const int rw = bio_data_dir(bi);
5936         enum stripe_result ret;
5937         struct stripe_head *sh;
5938         sector_t new_sector;
5939         int previous = 0, flags = 0;
5940         int seq, dd_idx;
5941
5942         seq = read_seqcount_begin(&conf->gen_lock);
5943
5944         if (unlikely(conf->reshape_progress != MaxSector)) {
5945                 enum reshape_loc loc = get_reshape_loc(mddev, conf,
5946                                                        logical_sector);
5947                 if (loc == LOC_INSIDE_RESHAPE) {
5948                         ret = STRIPE_SCHEDULE_AND_RETRY;
5949                         goto out;
5950                 }
5951                 if (loc == LOC_AHEAD_OF_RESHAPE)
5952                         previous = 1;
5953         }
5954
5955         new_sector = raid5_compute_sector(conf, logical_sector, previous,
5956                                           &dd_idx, NULL);
5957         pr_debug("raid456: %s, sector %llu logical %llu\n", __func__,
5958                  new_sector, logical_sector);
5959
5960         if (previous)
5961                 flags |= R5_GAS_PREVIOUS;
5962         if (bi->bi_opf & REQ_RAHEAD)
5963                 flags |= R5_GAS_NOBLOCK;
5964         sh = raid5_get_active_stripe(conf, ctx, new_sector, flags);
5965         if (unlikely(!sh)) {
5966                 /* cannot get stripe, just give-up */
5967                 bi->bi_status = BLK_STS_IOERR;
5968                 return STRIPE_FAIL;
5969         }
5970
5971         if (unlikely(previous) &&
5972             stripe_ahead_of_reshape(mddev, conf, sh)) {
5973                 /*
5974                  * Expansion moved on while waiting for a stripe.
5975                  * Expansion could still move past after this
5976                  * test, but as we are holding a reference to
5977                  * 'sh', we know that if that happens,
5978                  *  STRIPE_EXPANDING will get set and the expansion
5979                  * won't proceed until we finish with the stripe.
5980                  */
5981                 ret = STRIPE_SCHEDULE_AND_RETRY;
5982                 goto out_release;
5983         }
5984
5985         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5986                 /* Might have got the wrong stripe_head by accident */
5987                 ret = STRIPE_RETRY;
5988                 goto out_release;
5989         }
5990
5991         if (test_bit(STRIPE_EXPANDING, &sh->state)) {
5992                 md_wakeup_thread(mddev->thread);
5993                 ret = STRIPE_SCHEDULE_AND_RETRY;
5994                 goto out_release;
5995         }
5996
5997         if (!add_all_stripe_bios(conf, ctx, sh, bi, rw, previous)) {
5998                 ret = STRIPE_RETRY;
5999                 goto out;
6000         }
6001
6002         if (stripe_can_batch(sh)) {
6003                 stripe_add_to_batch_list(conf, sh, ctx->batch_last);
6004                 if (ctx->batch_last)
6005                         raid5_release_stripe(ctx->batch_last);
6006                 atomic_inc(&sh->count);
6007                 ctx->batch_last = sh;
6008         }
6009
6010         if (ctx->do_flush) {
6011                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
6012                 /* we only need flush for one stripe */
6013                 ctx->do_flush = false;
6014         }
6015
6016         set_bit(STRIPE_HANDLE, &sh->state);
6017         clear_bit(STRIPE_DELAYED, &sh->state);
6018         if ((!sh->batch_head || sh == sh->batch_head) &&
6019             (bi->bi_opf & REQ_SYNC) &&
6020             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
6021                 atomic_inc(&conf->preread_active_stripes);
6022
6023         release_stripe_plug(mddev, sh);
6024         return STRIPE_SUCCESS;
6025
6026 out_release:
6027         raid5_release_stripe(sh);
6028 out:
6029         if (ret == STRIPE_SCHEDULE_AND_RETRY && reshape_interrupted(mddev)) {
6030                 bi->bi_status = BLK_STS_RESOURCE;
6031                 ret = STRIPE_WAIT_RESHAPE;
6032                 pr_err_ratelimited("dm-raid456: io across reshape position while reshape can't make progress");
6033         }
6034         return ret;
6035 }
6036
6037 /*
6038  * If the bio covers multiple data disks, find sector within the bio that has
6039  * the lowest chunk offset in the first chunk.
6040  */
6041 static sector_t raid5_bio_lowest_chunk_sector(struct r5conf *conf,
6042                                               struct bio *bi)
6043 {
6044         int sectors_per_chunk = conf->chunk_sectors;
6045         int raid_disks = conf->raid_disks;
6046         int dd_idx;
6047         struct stripe_head sh;
6048         unsigned int chunk_offset;
6049         sector_t r_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6050         sector_t sector;
6051
6052         /* We pass in fake stripe_head to get back parity disk numbers */
6053         sector = raid5_compute_sector(conf, r_sector, 0, &dd_idx, &sh);
6054         chunk_offset = sector_div(sector, sectors_per_chunk);
6055         if (sectors_per_chunk - chunk_offset >= bio_sectors(bi))
6056                 return r_sector;
6057         /*
6058          * Bio crosses to the next data disk. Check whether it's in the same
6059          * chunk.
6060          */
6061         dd_idx++;
6062         while (dd_idx == sh.pd_idx || dd_idx == sh.qd_idx)
6063                 dd_idx++;
6064         if (dd_idx >= raid_disks)
6065                 return r_sector;
6066         return r_sector + sectors_per_chunk - chunk_offset;
6067 }
6068
6069 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
6070 {
6071         DEFINE_WAIT_FUNC(wait, woken_wake_function);
6072         bool on_wq;
6073         struct r5conf *conf = mddev->private;
6074         sector_t logical_sector;
6075         struct stripe_request_ctx ctx = {};
6076         const int rw = bio_data_dir(bi);
6077         enum stripe_result res;
6078         int s, stripe_cnt;
6079
6080         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
6081                 int ret = log_handle_flush_request(conf, bi);
6082
6083                 if (ret == 0)
6084                         return true;
6085                 if (ret == -ENODEV) {
6086                         if (md_flush_request(mddev, bi))
6087                                 return true;
6088                 }
6089                 /* ret == -EAGAIN, fallback */
6090                 /*
6091                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
6092                  * we need to flush journal device
6093                  */
6094                 ctx.do_flush = bi->bi_opf & REQ_PREFLUSH;
6095         }
6096
6097         md_write_start(mddev, bi);
6098         /*
6099          * If array is degraded, better not do chunk aligned read because
6100          * later we might have to read it again in order to reconstruct
6101          * data on failed drives.
6102          */
6103         if (rw == READ && mddev->degraded == 0 &&
6104             mddev->reshape_position == MaxSector) {
6105                 bi = chunk_aligned_read(mddev, bi);
6106                 if (!bi)
6107                         return true;
6108         }
6109
6110         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
6111                 make_discard_request(mddev, bi);
6112                 md_write_end(mddev);
6113                 return true;
6114         }
6115
6116         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6117         ctx.first_sector = logical_sector;
6118         ctx.last_sector = bio_end_sector(bi);
6119         bi->bi_next = NULL;
6120
6121         stripe_cnt = DIV_ROUND_UP_SECTOR_T(ctx.last_sector - logical_sector,
6122                                            RAID5_STRIPE_SECTORS(conf));
6123         bitmap_set(ctx.sectors_to_do, 0, stripe_cnt);
6124
6125         pr_debug("raid456: %s, logical %llu to %llu\n", __func__,
6126                  bi->bi_iter.bi_sector, ctx.last_sector);
6127
6128         /* Bail out if conflicts with reshape and REQ_NOWAIT is set */
6129         if ((bi->bi_opf & REQ_NOWAIT) &&
6130             (conf->reshape_progress != MaxSector) &&
6131             get_reshape_loc(mddev, conf, logical_sector) == LOC_INSIDE_RESHAPE) {
6132                 bio_wouldblock_error(bi);
6133                 if (rw == WRITE)
6134                         md_write_end(mddev);
6135                 return true;
6136         }
6137         md_account_bio(mddev, &bi);
6138
6139         /*
6140          * Lets start with the stripe with the lowest chunk offset in the first
6141          * chunk. That has the best chances of creating IOs adjacent to
6142          * previous IOs in case of sequential IO and thus creates the most
6143          * sequential IO pattern. We don't bother with the optimization when
6144          * reshaping as the performance benefit is not worth the complexity.
6145          */
6146         if (likely(conf->reshape_progress == MaxSector)) {
6147                 logical_sector = raid5_bio_lowest_chunk_sector(conf, bi);
6148                 on_wq = false;
6149         } else {
6150                 add_wait_queue(&conf->wait_for_reshape, &wait);
6151                 on_wq = true;
6152         }
6153         s = (logical_sector - ctx.first_sector) >> RAID5_STRIPE_SHIFT(conf);
6154
6155         while (1) {
6156                 res = make_stripe_request(mddev, conf, &ctx, logical_sector,
6157                                           bi);
6158                 if (res == STRIPE_FAIL || res == STRIPE_WAIT_RESHAPE)
6159                         break;
6160
6161                 if (res == STRIPE_RETRY)
6162                         continue;
6163
6164                 if (res == STRIPE_SCHEDULE_AND_RETRY) {
6165                         WARN_ON_ONCE(!on_wq);
6166                         /*
6167                          * Must release the reference to batch_last before
6168                          * scheduling and waiting for work to be done,
6169                          * otherwise the batch_last stripe head could prevent
6170                          * raid5_activate_delayed() from making progress
6171                          * and thus deadlocking.
6172                          */
6173                         if (ctx.batch_last) {
6174                                 raid5_release_stripe(ctx.batch_last);
6175                                 ctx.batch_last = NULL;
6176                         }
6177
6178                         wait_woken(&wait, TASK_UNINTERRUPTIBLE,
6179                                    MAX_SCHEDULE_TIMEOUT);
6180                         continue;
6181                 }
6182
6183                 s = find_next_bit_wrap(ctx.sectors_to_do, stripe_cnt, s);
6184                 if (s == stripe_cnt)
6185                         break;
6186
6187                 logical_sector = ctx.first_sector +
6188                         (s << RAID5_STRIPE_SHIFT(conf));
6189         }
6190         if (unlikely(on_wq))
6191                 remove_wait_queue(&conf->wait_for_reshape, &wait);
6192
6193         if (ctx.batch_last)
6194                 raid5_release_stripe(ctx.batch_last);
6195
6196         if (rw == WRITE)
6197                 md_write_end(mddev);
6198         if (res == STRIPE_WAIT_RESHAPE) {
6199                 md_free_cloned_bio(bi);
6200                 return false;
6201         }
6202
6203         bio_endio(bi);
6204         return true;
6205 }
6206
6207 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
6208
6209 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
6210 {
6211         /* reshaping is quite different to recovery/resync so it is
6212          * handled quite separately ... here.
6213          *
6214          * On each call to sync_request, we gather one chunk worth of
6215          * destination stripes and flag them as expanding.
6216          * Then we find all the source stripes and request reads.
6217          * As the reads complete, handle_stripe will copy the data
6218          * into the destination stripe and release that stripe.
6219          */
6220         struct r5conf *conf = mddev->private;
6221         struct stripe_head *sh;
6222         struct md_rdev *rdev;
6223         sector_t first_sector, last_sector;
6224         int raid_disks = conf->previous_raid_disks;
6225         int data_disks = raid_disks - conf->max_degraded;
6226         int new_data_disks = conf->raid_disks - conf->max_degraded;
6227         int i;
6228         int dd_idx;
6229         sector_t writepos, readpos, safepos;
6230         sector_t stripe_addr;
6231         int reshape_sectors;
6232         struct list_head stripes;
6233         sector_t retn;
6234
6235         if (sector_nr == 0) {
6236                 /* If restarting in the middle, skip the initial sectors */
6237                 if (mddev->reshape_backwards &&
6238                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
6239                         sector_nr = raid5_size(mddev, 0, 0)
6240                                 - conf->reshape_progress;
6241                 } else if (mddev->reshape_backwards &&
6242                            conf->reshape_progress == MaxSector) {
6243                         /* shouldn't happen, but just in case, finish up.*/
6244                         sector_nr = MaxSector;
6245                 } else if (!mddev->reshape_backwards &&
6246                            conf->reshape_progress > 0)
6247                         sector_nr = conf->reshape_progress;
6248                 sector_div(sector_nr, new_data_disks);
6249                 if (sector_nr) {
6250                         mddev->curr_resync_completed = sector_nr;
6251                         sysfs_notify_dirent_safe(mddev->sysfs_completed);
6252                         *skipped = 1;
6253                         retn = sector_nr;
6254                         goto finish;
6255                 }
6256         }
6257
6258         /* We need to process a full chunk at a time.
6259          * If old and new chunk sizes differ, we need to process the
6260          * largest of these
6261          */
6262
6263         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
6264
6265         /* We update the metadata at least every 10 seconds, or when
6266          * the data about to be copied would over-write the source of
6267          * the data at the front of the range.  i.e. one new_stripe
6268          * along from reshape_progress new_maps to after where
6269          * reshape_safe old_maps to
6270          */
6271         writepos = conf->reshape_progress;
6272         sector_div(writepos, new_data_disks);
6273         readpos = conf->reshape_progress;
6274         sector_div(readpos, data_disks);
6275         safepos = conf->reshape_safe;
6276         sector_div(safepos, data_disks);
6277         if (mddev->reshape_backwards) {
6278                 if (WARN_ON(writepos < reshape_sectors))
6279                         return MaxSector;
6280
6281                 writepos -= reshape_sectors;
6282                 readpos += reshape_sectors;
6283                 safepos += reshape_sectors;
6284         } else {
6285                 writepos += reshape_sectors;
6286                 /* readpos and safepos are worst-case calculations.
6287                  * A negative number is overly pessimistic, and causes
6288                  * obvious problems for unsigned storage.  So clip to 0.
6289                  */
6290                 readpos -= min_t(sector_t, reshape_sectors, readpos);
6291                 safepos -= min_t(sector_t, reshape_sectors, safepos);
6292         }
6293
6294         /* Having calculated the 'writepos' possibly use it
6295          * to set 'stripe_addr' which is where we will write to.
6296          */
6297         if (mddev->reshape_backwards) {
6298                 if (WARN_ON(conf->reshape_progress == 0))
6299                         return MaxSector;
6300
6301                 stripe_addr = writepos;
6302                 if (WARN_ON((mddev->dev_sectors &
6303                     ~((sector_t)reshape_sectors - 1)) -
6304                     reshape_sectors - stripe_addr != sector_nr))
6305                         return MaxSector;
6306         } else {
6307                 if (WARN_ON(writepos != sector_nr + reshape_sectors))
6308                         return MaxSector;
6309
6310                 stripe_addr = sector_nr;
6311         }
6312
6313         /* 'writepos' is the most advanced device address we might write.
6314          * 'readpos' is the least advanced device address we might read.
6315          * 'safepos' is the least address recorded in the metadata as having
6316          *     been reshaped.
6317          * If there is a min_offset_diff, these are adjusted either by
6318          * increasing the safepos/readpos if diff is negative, or
6319          * increasing writepos if diff is positive.
6320          * If 'readpos' is then behind 'writepos', there is no way that we can
6321          * ensure safety in the face of a crash - that must be done by userspace
6322          * making a backup of the data.  So in that case there is no particular
6323          * rush to update metadata.
6324          * Otherwise if 'safepos' is behind 'writepos', then we really need to
6325          * update the metadata to advance 'safepos' to match 'readpos' so that
6326          * we can be safe in the event of a crash.
6327          * So we insist on updating metadata if safepos is behind writepos and
6328          * readpos is beyond writepos.
6329          * In any case, update the metadata every 10 seconds.
6330          * Maybe that number should be configurable, but I'm not sure it is
6331          * worth it.... maybe it could be a multiple of safemode_delay???
6332          */
6333         if (conf->min_offset_diff < 0) {
6334                 safepos += -conf->min_offset_diff;
6335                 readpos += -conf->min_offset_diff;
6336         } else
6337                 writepos += conf->min_offset_diff;
6338
6339         if ((mddev->reshape_backwards
6340              ? (safepos > writepos && readpos < writepos)
6341              : (safepos < writepos && readpos > writepos)) ||
6342             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
6343                 /* Cannot proceed until we've updated the superblock... */
6344                 wait_event(conf->wait_for_reshape,
6345                            atomic_read(&conf->reshape_stripes)==0
6346                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6347                 if (atomic_read(&conf->reshape_stripes) != 0)
6348                         return 0;
6349                 mddev->reshape_position = conf->reshape_progress;
6350                 mddev->curr_resync_completed = sector_nr;
6351                 if (!mddev->reshape_backwards)
6352                         /* Can update recovery_offset */
6353                         rdev_for_each(rdev, mddev)
6354                                 if (rdev->raid_disk >= 0 &&
6355                                     !test_bit(Journal, &rdev->flags) &&
6356                                     !test_bit(In_sync, &rdev->flags) &&
6357                                     rdev->recovery_offset < sector_nr)
6358                                         rdev->recovery_offset = sector_nr;
6359
6360                 conf->reshape_checkpoint = jiffies;
6361                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6362                 md_wakeup_thread(mddev->thread);
6363                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
6364                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6365                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6366                         return 0;
6367                 spin_lock_irq(&conf->device_lock);
6368                 conf->reshape_safe = mddev->reshape_position;
6369                 spin_unlock_irq(&conf->device_lock);
6370                 wake_up(&conf->wait_for_reshape);
6371                 sysfs_notify_dirent_safe(mddev->sysfs_completed);
6372         }
6373
6374         INIT_LIST_HEAD(&stripes);
6375         for (i = 0; i < reshape_sectors; i += RAID5_STRIPE_SECTORS(conf)) {
6376                 int j;
6377                 int skipped_disk = 0;
6378                 sh = raid5_get_active_stripe(conf, NULL, stripe_addr+i,
6379                                              R5_GAS_NOQUIESCE);
6380                 set_bit(STRIPE_EXPANDING, &sh->state);
6381                 atomic_inc(&conf->reshape_stripes);
6382                 /* If any of this stripe is beyond the end of the old
6383                  * array, then we need to zero those blocks
6384                  */
6385                 for (j=sh->disks; j--;) {
6386                         sector_t s;
6387                         if (j == sh->pd_idx)
6388                                 continue;
6389                         if (conf->level == 6 &&
6390                             j == sh->qd_idx)
6391                                 continue;
6392                         s = raid5_compute_blocknr(sh, j, 0);
6393                         if (s < raid5_size(mddev, 0, 0)) {
6394                                 skipped_disk = 1;
6395                                 continue;
6396                         }
6397                         memset(page_address(sh->dev[j].page), 0, RAID5_STRIPE_SIZE(conf));
6398                         set_bit(R5_Expanded, &sh->dev[j].flags);
6399                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
6400                 }
6401                 if (!skipped_disk) {
6402                         set_bit(STRIPE_EXPAND_READY, &sh->state);
6403                         set_bit(STRIPE_HANDLE, &sh->state);
6404                 }
6405                 list_add(&sh->lru, &stripes);
6406         }
6407         spin_lock_irq(&conf->device_lock);
6408         if (mddev->reshape_backwards)
6409                 conf->reshape_progress -= reshape_sectors * new_data_disks;
6410         else
6411                 conf->reshape_progress += reshape_sectors * new_data_disks;
6412         spin_unlock_irq(&conf->device_lock);
6413         /* Ok, those stripe are ready. We can start scheduling
6414          * reads on the source stripes.
6415          * The source stripes are determined by mapping the first and last
6416          * block on the destination stripes.
6417          */
6418         first_sector =
6419                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
6420                                      1, &dd_idx, NULL);
6421         last_sector =
6422                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
6423                                             * new_data_disks - 1),
6424                                      1, &dd_idx, NULL);
6425         if (last_sector >= mddev->dev_sectors)
6426                 last_sector = mddev->dev_sectors - 1;
6427         while (first_sector <= last_sector) {
6428                 sh = raid5_get_active_stripe(conf, NULL, first_sector,
6429                                 R5_GAS_PREVIOUS | R5_GAS_NOQUIESCE);
6430                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
6431                 set_bit(STRIPE_HANDLE, &sh->state);
6432                 raid5_release_stripe(sh);
6433                 first_sector += RAID5_STRIPE_SECTORS(conf);
6434         }
6435         /* Now that the sources are clearly marked, we can release
6436          * the destination stripes
6437          */
6438         while (!list_empty(&stripes)) {
6439                 sh = list_entry(stripes.next, struct stripe_head, lru);
6440                 list_del_init(&sh->lru);
6441                 raid5_release_stripe(sh);
6442         }
6443         /* If this takes us to the resync_max point where we have to pause,
6444          * then we need to write out the superblock.
6445          */
6446         sector_nr += reshape_sectors;
6447         retn = reshape_sectors;
6448 finish:
6449         if (mddev->curr_resync_completed > mddev->resync_max ||
6450             (sector_nr - mddev->curr_resync_completed) * 2
6451             >= mddev->resync_max - mddev->curr_resync_completed) {
6452                 /* Cannot proceed until we've updated the superblock... */
6453                 wait_event(conf->wait_for_reshape,
6454                            atomic_read(&conf->reshape_stripes) == 0
6455                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6456                 if (atomic_read(&conf->reshape_stripes) != 0)
6457                         goto ret;
6458                 mddev->reshape_position = conf->reshape_progress;
6459                 mddev->curr_resync_completed = sector_nr;
6460                 if (!mddev->reshape_backwards)
6461                         /* Can update recovery_offset */
6462                         rdev_for_each(rdev, mddev)
6463                                 if (rdev->raid_disk >= 0 &&
6464                                     !test_bit(Journal, &rdev->flags) &&
6465                                     !test_bit(In_sync, &rdev->flags) &&
6466                                     rdev->recovery_offset < sector_nr)
6467                                         rdev->recovery_offset = sector_nr;
6468                 conf->reshape_checkpoint = jiffies;
6469                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
6470                 md_wakeup_thread(mddev->thread);
6471                 wait_event(mddev->sb_wait,
6472                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
6473                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
6474                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
6475                         goto ret;
6476                 spin_lock_irq(&conf->device_lock);
6477                 conf->reshape_safe = mddev->reshape_position;
6478                 spin_unlock_irq(&conf->device_lock);
6479                 wake_up(&conf->wait_for_reshape);
6480                 sysfs_notify_dirent_safe(mddev->sysfs_completed);
6481         }
6482 ret:
6483         return retn;
6484 }
6485
6486 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
6487                                           sector_t max_sector, int *skipped)
6488 {
6489         struct r5conf *conf = mddev->private;
6490         struct stripe_head *sh;
6491         sector_t sync_blocks;
6492         bool still_degraded = false;
6493         int i;
6494
6495         if (sector_nr >= max_sector) {
6496                 /* just being told to finish up .. nothing much to do */
6497
6498                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6499                         end_reshape(conf);
6500                         return 0;
6501                 }
6502
6503                 if (mddev->curr_resync < max_sector) /* aborted */
6504                         mddev->bitmap_ops->end_sync(mddev, mddev->curr_resync,
6505                                                     &sync_blocks);
6506                 else /* completed sync */
6507                         conf->fullsync = 0;
6508                 mddev->bitmap_ops->close_sync(mddev);
6509
6510                 return 0;
6511         }
6512
6513         /* Allow raid5_quiesce to complete */
6514         wait_event(conf->wait_for_reshape, conf->quiesce != 2);
6515
6516         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6517                 return reshape_request(mddev, sector_nr, skipped);
6518
6519         /* No need to check resync_max as we never do more than one
6520          * stripe, and as resync_max will always be on a chunk boundary,
6521          * if the check in md_do_sync didn't fire, there is no chance
6522          * of overstepping resync_max here
6523          */
6524
6525         /* if there is too many failed drives and we are trying
6526          * to resync, then assert that we are finished, because there is
6527          * nothing we can do.
6528          */
6529         if (mddev->degraded >= conf->max_degraded &&
6530             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6531                 sector_t rv = mddev->dev_sectors - sector_nr;
6532                 *skipped = 1;
6533                 return rv;
6534         }
6535         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6536             !conf->fullsync &&
6537             !mddev->bitmap_ops->start_sync(mddev, sector_nr, &sync_blocks,
6538                                            true) &&
6539             sync_blocks >= RAID5_STRIPE_SECTORS(conf)) {
6540                 /* we can skip this block, and probably more */
6541                 do_div(sync_blocks, RAID5_STRIPE_SECTORS(conf));
6542                 *skipped = 1;
6543                 /* keep things rounded to whole stripes */
6544                 return sync_blocks * RAID5_STRIPE_SECTORS(conf);
6545         }
6546
6547         mddev->bitmap_ops->cond_end_sync(mddev, sector_nr, false);
6548
6549         sh = raid5_get_active_stripe(conf, NULL, sector_nr,
6550                                      R5_GAS_NOBLOCK);
6551         if (sh == NULL) {
6552                 sh = raid5_get_active_stripe(conf, NULL, sector_nr, 0);
6553                 /* make sure we don't swamp the stripe cache if someone else
6554                  * is trying to get access
6555                  */
6556                 schedule_timeout_uninterruptible(1);
6557         }
6558         /* Need to check if array will still be degraded after recovery/resync
6559          * Note in case of > 1 drive failures it's possible we're rebuilding
6560          * one drive while leaving another faulty drive in array.
6561          */
6562         for (i = 0; i < conf->raid_disks; i++) {
6563                 struct md_rdev *rdev = conf->disks[i].rdev;
6564
6565                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6566                         still_degraded = true;
6567         }
6568
6569         mddev->bitmap_ops->start_sync(mddev, sector_nr, &sync_blocks,
6570                                       still_degraded);
6571
6572         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6573         set_bit(STRIPE_HANDLE, &sh->state);
6574
6575         raid5_release_stripe(sh);
6576
6577         return RAID5_STRIPE_SECTORS(conf);
6578 }
6579
6580 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6581                                unsigned int offset)
6582 {
6583         /* We may not be able to submit a whole bio at once as there
6584          * may not be enough stripe_heads available.
6585          * We cannot pre-allocate enough stripe_heads as we may need
6586          * more than exist in the cache (if we allow ever large chunks).
6587          * So we do one stripe head at a time and record in
6588          * ->bi_hw_segments how many have been done.
6589          *
6590          * We *know* that this entire raid_bio is in one chunk, so
6591          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6592          */
6593         struct stripe_head *sh;
6594         int dd_idx;
6595         sector_t sector, logical_sector, last_sector;
6596         int scnt = 0;
6597         int handled = 0;
6598
6599         logical_sector = raid_bio->bi_iter.bi_sector &
6600                 ~((sector_t)RAID5_STRIPE_SECTORS(conf)-1);
6601         sector = raid5_compute_sector(conf, logical_sector,
6602                                       0, &dd_idx, NULL);
6603         last_sector = bio_end_sector(raid_bio);
6604
6605         for (; logical_sector < last_sector;
6606              logical_sector += RAID5_STRIPE_SECTORS(conf),
6607                      sector += RAID5_STRIPE_SECTORS(conf),
6608                      scnt++) {
6609
6610                 if (scnt < offset)
6611                         /* already done this stripe */
6612                         continue;
6613
6614                 sh = raid5_get_active_stripe(conf, NULL, sector,
6615                                 R5_GAS_NOBLOCK | R5_GAS_NOQUIESCE);
6616                 if (!sh) {
6617                         /* failed to get a stripe - must wait */
6618                         conf->retry_read_aligned = raid_bio;
6619                         conf->retry_read_offset = scnt;
6620                         return handled;
6621                 }
6622
6623                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6624                         raid5_release_stripe(sh);
6625                         conf->retry_read_aligned = raid_bio;
6626                         conf->retry_read_offset = scnt;
6627                         return handled;
6628                 }
6629
6630                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6631                 handle_stripe(sh);
6632                 raid5_release_stripe(sh);
6633                 handled++;
6634         }
6635
6636         bio_endio(raid_bio);
6637
6638         if (atomic_dec_and_test(&conf->active_aligned_reads))
6639                 wake_up(&conf->wait_for_quiescent);
6640         return handled;
6641 }
6642
6643 static int handle_active_stripes(struct r5conf *conf, int group,
6644                                  struct r5worker *worker,
6645                                  struct list_head *temp_inactive_list)
6646                 __must_hold(&conf->device_lock)
6647 {
6648         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6649         int i, batch_size = 0, hash;
6650         bool release_inactive = false;
6651
6652         while (batch_size < MAX_STRIPE_BATCH &&
6653                         (sh = __get_priority_stripe(conf, group)) != NULL)
6654                 batch[batch_size++] = sh;
6655
6656         if (batch_size == 0) {
6657                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6658                         if (!list_empty(temp_inactive_list + i))
6659                                 break;
6660                 if (i == NR_STRIPE_HASH_LOCKS) {
6661                         spin_unlock_irq(&conf->device_lock);
6662                         log_flush_stripe_to_raid(conf);
6663                         spin_lock_irq(&conf->device_lock);
6664                         return batch_size;
6665                 }
6666                 release_inactive = true;
6667         }
6668         spin_unlock_irq(&conf->device_lock);
6669
6670         release_inactive_stripe_list(conf, temp_inactive_list,
6671                                      NR_STRIPE_HASH_LOCKS);
6672
6673         r5l_flush_stripe_to_raid(conf->log);
6674         if (release_inactive) {
6675                 spin_lock_irq(&conf->device_lock);
6676                 return 0;
6677         }
6678
6679         for (i = 0; i < batch_size; i++)
6680                 handle_stripe(batch[i]);
6681         log_write_stripe_run(conf);
6682
6683         cond_resched();
6684
6685         spin_lock_irq(&conf->device_lock);
6686         for (i = 0; i < batch_size; i++) {
6687                 hash = batch[i]->hash_lock_index;
6688                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6689         }
6690         return batch_size;
6691 }
6692
6693 static void raid5_do_work(struct work_struct *work)
6694 {
6695         struct r5worker *worker = container_of(work, struct r5worker, work);
6696         struct r5worker_group *group = worker->group;
6697         struct r5conf *conf = group->conf;
6698         struct mddev *mddev = conf->mddev;
6699         int group_id = group - conf->worker_groups;
6700         int handled;
6701         struct blk_plug plug;
6702
6703         pr_debug("+++ raid5worker active\n");
6704
6705         blk_start_plug(&plug);
6706         handled = 0;
6707         spin_lock_irq(&conf->device_lock);
6708         while (1) {
6709                 int batch_size, released;
6710
6711                 released = release_stripe_list(conf, worker->temp_inactive_list);
6712
6713                 batch_size = handle_active_stripes(conf, group_id, worker,
6714                                                    worker->temp_inactive_list);
6715                 worker->working = false;
6716                 if (!batch_size && !released)
6717                         break;
6718                 handled += batch_size;
6719                 wait_event_lock_irq(mddev->sb_wait,
6720                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6721                         conf->device_lock);
6722         }
6723         pr_debug("%d stripes handled\n", handled);
6724
6725         spin_unlock_irq(&conf->device_lock);
6726
6727         flush_deferred_bios(conf);
6728
6729         r5l_flush_stripe_to_raid(conf->log);
6730
6731         async_tx_issue_pending_all();
6732         blk_finish_plug(&plug);
6733
6734         pr_debug("--- raid5worker inactive\n");
6735 }
6736
6737 /*
6738  * This is our raid5 kernel thread.
6739  *
6740  * We scan the hash table for stripes which can be handled now.
6741  * During the scan, completed stripes are saved for us by the interrupt
6742  * handler, so that they will not have to wait for our next wakeup.
6743  */
6744 static void raid5d(struct md_thread *thread)
6745 {
6746         struct mddev *mddev = thread->mddev;
6747         struct r5conf *conf = mddev->private;
6748         int handled;
6749         struct blk_plug plug;
6750
6751         pr_debug("+++ raid5d active\n");
6752
6753         md_check_recovery(mddev);
6754
6755         blk_start_plug(&plug);
6756         handled = 0;
6757         spin_lock_irq(&conf->device_lock);
6758         while (1) {
6759                 struct bio *bio;
6760                 int batch_size, released;
6761                 unsigned int offset;
6762
6763                 if (test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags))
6764                         break;
6765
6766                 released = release_stripe_list(conf, conf->temp_inactive_list);
6767                 if (released)
6768                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6769
6770                 if (
6771                     !list_empty(&conf->bitmap_list)) {
6772                         /* Now is a good time to flush some bitmap updates */
6773                         conf->seq_flush++;
6774                         spin_unlock_irq(&conf->device_lock);
6775                         mddev->bitmap_ops->unplug(mddev, true);
6776                         spin_lock_irq(&conf->device_lock);
6777                         conf->seq_write = conf->seq_flush;
6778                         activate_bit_delay(conf, conf->temp_inactive_list);
6779                 }
6780                 raid5_activate_delayed(conf);
6781
6782                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6783                         int ok;
6784                         spin_unlock_irq(&conf->device_lock);
6785                         ok = retry_aligned_read(conf, bio, offset);
6786                         spin_lock_irq(&conf->device_lock);
6787                         if (!ok)
6788                                 break;
6789                         handled++;
6790                 }
6791
6792                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6793                                                    conf->temp_inactive_list);
6794                 if (!batch_size && !released)
6795                         break;
6796                 handled += batch_size;
6797
6798                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6799                         spin_unlock_irq(&conf->device_lock);
6800                         md_check_recovery(mddev);
6801                         spin_lock_irq(&conf->device_lock);
6802                 }
6803         }
6804         pr_debug("%d stripes handled\n", handled);
6805
6806         spin_unlock_irq(&conf->device_lock);
6807         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6808             mutex_trylock(&conf->cache_size_mutex)) {
6809                 grow_one_stripe(conf, __GFP_NOWARN);
6810                 /* Set flag even if allocation failed.  This helps
6811                  * slow down allocation requests when mem is short
6812                  */
6813                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6814                 mutex_unlock(&conf->cache_size_mutex);
6815         }
6816
6817         flush_deferred_bios(conf);
6818
6819         r5l_flush_stripe_to_raid(conf->log);
6820
6821         async_tx_issue_pending_all();
6822         blk_finish_plug(&plug);
6823
6824         pr_debug("--- raid5d inactive\n");
6825 }
6826
6827 static ssize_t
6828 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6829 {
6830         struct r5conf *conf;
6831         int ret = 0;
6832         spin_lock(&mddev->lock);
6833         conf = mddev->private;
6834         if (conf)
6835                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6836         spin_unlock(&mddev->lock);
6837         return ret;
6838 }
6839
6840 int
6841 raid5_set_cache_size(struct mddev *mddev, int size)
6842 {
6843         int result = 0;
6844         struct r5conf *conf = mddev->private;
6845
6846         if (size <= 16 || size > 32768)
6847                 return -EINVAL;
6848
6849         WRITE_ONCE(conf->min_nr_stripes, size);
6850         mutex_lock(&conf->cache_size_mutex);
6851         while (size < conf->max_nr_stripes &&
6852                drop_one_stripe(conf))
6853                 ;
6854         mutex_unlock(&conf->cache_size_mutex);
6855
6856         md_allow_write(mddev);
6857
6858         mutex_lock(&conf->cache_size_mutex);
6859         while (size > conf->max_nr_stripes)
6860                 if (!grow_one_stripe(conf, GFP_KERNEL)) {
6861                         WRITE_ONCE(conf->min_nr_stripes, conf->max_nr_stripes);
6862                         result = -ENOMEM;
6863                         break;
6864                 }
6865         mutex_unlock(&conf->cache_size_mutex);
6866
6867         return result;
6868 }
6869 EXPORT_SYMBOL(raid5_set_cache_size);
6870
6871 static ssize_t
6872 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6873 {
6874         struct r5conf *conf;
6875         unsigned long new;
6876         int err;
6877
6878         if (len >= PAGE_SIZE)
6879                 return -EINVAL;
6880         if (kstrtoul(page, 10, &new))
6881                 return -EINVAL;
6882         err = mddev_lock(mddev);
6883         if (err)
6884                 return err;
6885         conf = mddev->private;
6886         if (!conf)
6887                 err = -ENODEV;
6888         else
6889                 err = raid5_set_cache_size(mddev, new);
6890         mddev_unlock(mddev);
6891
6892         return err ?: len;
6893 }
6894
6895 static struct md_sysfs_entry
6896 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6897                                 raid5_show_stripe_cache_size,
6898                                 raid5_store_stripe_cache_size);
6899
6900 static ssize_t
6901 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6902 {
6903         struct r5conf *conf = mddev->private;
6904         if (conf)
6905                 return sprintf(page, "%d\n", conf->rmw_level);
6906         else
6907                 return 0;
6908 }
6909
6910 static ssize_t
6911 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6912 {
6913         struct r5conf *conf = mddev->private;
6914         unsigned long new;
6915
6916         if (!conf)
6917                 return -ENODEV;
6918
6919         if (len >= PAGE_SIZE)
6920                 return -EINVAL;
6921
6922         if (kstrtoul(page, 10, &new))
6923                 return -EINVAL;
6924
6925         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6926                 return -EINVAL;
6927
6928         if (new != PARITY_DISABLE_RMW &&
6929             new != PARITY_ENABLE_RMW &&
6930             new != PARITY_PREFER_RMW)
6931                 return -EINVAL;
6932
6933         conf->rmw_level = new;
6934         return len;
6935 }
6936
6937 static struct md_sysfs_entry
6938 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6939                          raid5_show_rmw_level,
6940                          raid5_store_rmw_level);
6941
6942 static ssize_t
6943 raid5_show_stripe_size(struct mddev  *mddev, char *page)
6944 {
6945         struct r5conf *conf;
6946         int ret = 0;
6947
6948         spin_lock(&mddev->lock);
6949         conf = mddev->private;
6950         if (conf)
6951                 ret = sprintf(page, "%lu\n", RAID5_STRIPE_SIZE(conf));
6952         spin_unlock(&mddev->lock);
6953         return ret;
6954 }
6955
6956 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
6957 static ssize_t
6958 raid5_store_stripe_size(struct mddev  *mddev, const char *page, size_t len)
6959 {
6960         struct r5conf *conf;
6961         unsigned long new;
6962         int err;
6963         int size;
6964
6965         if (len >= PAGE_SIZE)
6966                 return -EINVAL;
6967         if (kstrtoul(page, 10, &new))
6968                 return -EINVAL;
6969
6970         /*
6971          * The value should not be bigger than PAGE_SIZE. It requires to
6972          * be multiple of DEFAULT_STRIPE_SIZE and the value should be power
6973          * of two.
6974          */
6975         if (new % DEFAULT_STRIPE_SIZE != 0 ||
6976                         new > PAGE_SIZE || new == 0 ||
6977                         new != roundup_pow_of_two(new))
6978                 return -EINVAL;
6979
6980         err = mddev_suspend_and_lock(mddev);
6981         if (err)
6982                 return err;
6983
6984         conf = mddev->private;
6985         if (!conf) {
6986                 err = -ENODEV;
6987                 goto out_unlock;
6988         }
6989
6990         if (new == conf->stripe_size)
6991                 goto out_unlock;
6992
6993         pr_debug("md/raid: change stripe_size from %lu to %lu\n",
6994                         conf->stripe_size, new);
6995
6996         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) ||
6997             mddev->reshape_position != MaxSector || mddev->sysfs_active) {
6998                 err = -EBUSY;
6999                 goto out_unlock;
7000         }
7001
7002         mutex_lock(&conf->cache_size_mutex);
7003         size = conf->max_nr_stripes;
7004
7005         shrink_stripes(conf);
7006
7007         conf->stripe_size = new;
7008         conf->stripe_shift = ilog2(new) - 9;
7009         conf->stripe_sectors = new >> 9;
7010         if (grow_stripes(conf, size)) {
7011                 pr_warn("md/raid:%s: couldn't allocate buffers\n",
7012                                 mdname(mddev));
7013                 err = -ENOMEM;
7014         }
7015         mutex_unlock(&conf->cache_size_mutex);
7016
7017 out_unlock:
7018         mddev_unlock_and_resume(mddev);
7019         return err ?: len;
7020 }
7021
7022 static struct md_sysfs_entry
7023 raid5_stripe_size = __ATTR(stripe_size, 0644,
7024                          raid5_show_stripe_size,
7025                          raid5_store_stripe_size);
7026 #else
7027 static struct md_sysfs_entry
7028 raid5_stripe_size = __ATTR(stripe_size, 0444,
7029                          raid5_show_stripe_size,
7030                          NULL);
7031 #endif
7032
7033 static ssize_t
7034 raid5_show_preread_threshold(struct mddev *mddev, char *page)
7035 {
7036         struct r5conf *conf;
7037         int ret = 0;
7038         spin_lock(&mddev->lock);
7039         conf = mddev->private;
7040         if (conf)
7041                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
7042         spin_unlock(&mddev->lock);
7043         return ret;
7044 }
7045
7046 static ssize_t
7047 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
7048 {
7049         struct r5conf *conf;
7050         unsigned long new;
7051         int err;
7052
7053         if (len >= PAGE_SIZE)
7054                 return -EINVAL;
7055         if (kstrtoul(page, 10, &new))
7056                 return -EINVAL;
7057
7058         err = mddev_lock(mddev);
7059         if (err)
7060                 return err;
7061         conf = mddev->private;
7062         if (!conf)
7063                 err = -ENODEV;
7064         else if (new > conf->min_nr_stripes)
7065                 err = -EINVAL;
7066         else
7067                 conf->bypass_threshold = new;
7068         mddev_unlock(mddev);
7069         return err ?: len;
7070 }
7071
7072 static struct md_sysfs_entry
7073 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
7074                                         S_IRUGO | S_IWUSR,
7075                                         raid5_show_preread_threshold,
7076                                         raid5_store_preread_threshold);
7077
7078 static ssize_t
7079 raid5_show_skip_copy(struct mddev *mddev, char *page)
7080 {
7081         struct r5conf *conf;
7082         int ret = 0;
7083         spin_lock(&mddev->lock);
7084         conf = mddev->private;
7085         if (conf)
7086                 ret = sprintf(page, "%d\n", conf->skip_copy);
7087         spin_unlock(&mddev->lock);
7088         return ret;
7089 }
7090
7091 static ssize_t
7092 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
7093 {
7094         struct r5conf *conf;
7095         unsigned long new;
7096         int err;
7097
7098         if (len >= PAGE_SIZE)
7099                 return -EINVAL;
7100         if (kstrtoul(page, 10, &new))
7101                 return -EINVAL;
7102         new = !!new;
7103
7104         err = mddev_suspend_and_lock(mddev);
7105         if (err)
7106                 return err;
7107         conf = mddev->private;
7108         if (!conf)
7109                 err = -ENODEV;
7110         else if (new != conf->skip_copy) {
7111                 struct request_queue *q = mddev->gendisk->queue;
7112                 struct queue_limits lim = queue_limits_start_update(q);
7113
7114                 conf->skip_copy = new;
7115                 if (new)
7116                         lim.features |= BLK_FEAT_STABLE_WRITES;
7117                 else
7118                         lim.features &= ~BLK_FEAT_STABLE_WRITES;
7119                 err = queue_limits_commit_update(q, &lim);
7120         }
7121         mddev_unlock_and_resume(mddev);
7122         return err ?: len;
7123 }
7124
7125 static struct md_sysfs_entry
7126 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
7127                                         raid5_show_skip_copy,
7128                                         raid5_store_skip_copy);
7129
7130 static ssize_t
7131 stripe_cache_active_show(struct mddev *mddev, char *page)
7132 {
7133         struct r5conf *conf = mddev->private;
7134         if (conf)
7135                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
7136         else
7137                 return 0;
7138 }
7139
7140 static struct md_sysfs_entry
7141 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
7142
7143 static ssize_t
7144 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
7145 {
7146         struct r5conf *conf;
7147         int ret = 0;
7148         spin_lock(&mddev->lock);
7149         conf = mddev->private;
7150         if (conf)
7151                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
7152         spin_unlock(&mddev->lock);
7153         return ret;
7154 }
7155
7156 static int alloc_thread_groups(struct r5conf *conf, int cnt,
7157                                int *group_cnt,
7158                                struct r5worker_group **worker_groups);
7159 static ssize_t
7160 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
7161 {
7162         struct r5conf *conf;
7163         unsigned int new;
7164         int err;
7165         struct r5worker_group *new_groups, *old_groups;
7166         int group_cnt;
7167
7168         if (len >= PAGE_SIZE)
7169                 return -EINVAL;
7170         if (kstrtouint(page, 10, &new))
7171                 return -EINVAL;
7172         /* 8192 should be big enough */
7173         if (new > 8192)
7174                 return -EINVAL;
7175
7176         err = mddev_suspend_and_lock(mddev);
7177         if (err)
7178                 return err;
7179         raid5_quiesce(mddev, true);
7180
7181         conf = mddev->private;
7182         if (!conf)
7183                 err = -ENODEV;
7184         else if (new != conf->worker_cnt_per_group) {
7185                 old_groups = conf->worker_groups;
7186                 if (old_groups)
7187                         flush_workqueue(raid5_wq);
7188
7189                 err = alloc_thread_groups(conf, new, &group_cnt, &new_groups);
7190                 if (!err) {
7191                         spin_lock_irq(&conf->device_lock);
7192                         conf->group_cnt = group_cnt;
7193                         conf->worker_cnt_per_group = new;
7194                         conf->worker_groups = new_groups;
7195                         spin_unlock_irq(&conf->device_lock);
7196
7197                         if (old_groups)
7198                                 kfree(old_groups[0].workers);
7199                         kfree(old_groups);
7200                 }
7201         }
7202
7203         raid5_quiesce(mddev, false);
7204         mddev_unlock_and_resume(mddev);
7205
7206         return err ?: len;
7207 }
7208
7209 static struct md_sysfs_entry
7210 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
7211                                 raid5_show_group_thread_cnt,
7212                                 raid5_store_group_thread_cnt);
7213
7214 static struct attribute *raid5_attrs[] =  {
7215         &raid5_stripecache_size.attr,
7216         &raid5_stripecache_active.attr,
7217         &raid5_preread_bypass_threshold.attr,
7218         &raid5_group_thread_cnt.attr,
7219         &raid5_skip_copy.attr,
7220         &raid5_rmw_level.attr,
7221         &raid5_stripe_size.attr,
7222         &r5c_journal_mode.attr,
7223         &ppl_write_hint.attr,
7224         NULL,
7225 };
7226 static const struct attribute_group raid5_attrs_group = {
7227         .name = NULL,
7228         .attrs = raid5_attrs,
7229 };
7230
7231 static int alloc_thread_groups(struct r5conf *conf, int cnt, int *group_cnt,
7232                                struct r5worker_group **worker_groups)
7233 {
7234         int i, j, k;
7235         ssize_t size;
7236         struct r5worker *workers;
7237
7238         if (cnt == 0) {
7239                 *group_cnt = 0;
7240                 *worker_groups = NULL;
7241                 return 0;
7242         }
7243         *group_cnt = num_possible_nodes();
7244         size = sizeof(struct r5worker) * cnt;
7245         workers = kcalloc(size, *group_cnt, GFP_NOIO);
7246         *worker_groups = kcalloc(*group_cnt, sizeof(struct r5worker_group),
7247                                  GFP_NOIO);
7248         if (!*worker_groups || !workers) {
7249                 kfree(workers);
7250                 kfree(*worker_groups);
7251                 return -ENOMEM;
7252         }
7253
7254         for (i = 0; i < *group_cnt; i++) {
7255                 struct r5worker_group *group;
7256
7257                 group = &(*worker_groups)[i];
7258                 INIT_LIST_HEAD(&group->handle_list);
7259                 INIT_LIST_HEAD(&group->loprio_list);
7260                 group->conf = conf;
7261                 group->workers = workers + i * cnt;
7262
7263                 for (j = 0; j < cnt; j++) {
7264                         struct r5worker *worker = group->workers + j;
7265                         worker->group = group;
7266                         INIT_WORK(&worker->work, raid5_do_work);
7267
7268                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
7269                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
7270                 }
7271         }
7272
7273         return 0;
7274 }
7275
7276 static void free_thread_groups(struct r5conf *conf)
7277 {
7278         if (conf->worker_groups)
7279                 kfree(conf->worker_groups[0].workers);
7280         kfree(conf->worker_groups);
7281         conf->worker_groups = NULL;
7282 }
7283
7284 static sector_t
7285 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
7286 {
7287         struct r5conf *conf = mddev->private;
7288
7289         if (!sectors)
7290                 sectors = mddev->dev_sectors;
7291         if (!raid_disks)
7292                 /* size is defined by the smallest of previous and new size */
7293                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
7294
7295         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7296         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
7297         return sectors * (raid_disks - conf->max_degraded);
7298 }
7299
7300 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7301 {
7302         safe_put_page(percpu->spare_page);
7303         percpu->spare_page = NULL;
7304         kvfree(percpu->scribble);
7305         percpu->scribble = NULL;
7306 }
7307
7308 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
7309 {
7310         if (conf->level == 6 && !percpu->spare_page) {
7311                 percpu->spare_page = alloc_page(GFP_KERNEL);
7312                 if (!percpu->spare_page)
7313                         return -ENOMEM;
7314         }
7315
7316         if (scribble_alloc(percpu,
7317                            max(conf->raid_disks,
7318                                conf->previous_raid_disks),
7319                            max(conf->chunk_sectors,
7320                                conf->prev_chunk_sectors)
7321                            / RAID5_STRIPE_SECTORS(conf))) {
7322                 free_scratch_buffer(conf, percpu);
7323                 return -ENOMEM;
7324         }
7325
7326         local_lock_init(&percpu->lock);
7327         return 0;
7328 }
7329
7330 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
7331 {
7332         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7333
7334         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
7335         return 0;
7336 }
7337
7338 static void raid5_free_percpu(struct r5conf *conf)
7339 {
7340         if (!conf->percpu)
7341                 return;
7342
7343         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7344         free_percpu(conf->percpu);
7345 }
7346
7347 static void free_conf(struct r5conf *conf)
7348 {
7349         int i;
7350
7351         log_exit(conf);
7352
7353         shrinker_free(conf->shrinker);
7354         free_thread_groups(conf);
7355         shrink_stripes(conf);
7356         raid5_free_percpu(conf);
7357         for (i = 0; i < conf->pool_size; i++)
7358                 if (conf->disks[i].extra_page)
7359                         put_page(conf->disks[i].extra_page);
7360         kfree(conf->disks);
7361         bioset_exit(&conf->bio_split);
7362         kfree(conf->stripe_hashtbl);
7363         kfree(conf->pending_data);
7364         kfree(conf);
7365 }
7366
7367 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
7368 {
7369         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
7370         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
7371
7372         if (alloc_scratch_buffer(conf, percpu)) {
7373                 pr_warn("%s: failed memory allocation for cpu%u\n",
7374                         __func__, cpu);
7375                 return -ENOMEM;
7376         }
7377         return 0;
7378 }
7379
7380 static int raid5_alloc_percpu(struct r5conf *conf)
7381 {
7382         int err = 0;
7383
7384         conf->percpu = alloc_percpu(struct raid5_percpu);
7385         if (!conf->percpu)
7386                 return -ENOMEM;
7387
7388         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
7389         if (!err) {
7390                 conf->scribble_disks = max(conf->raid_disks,
7391                         conf->previous_raid_disks);
7392                 conf->scribble_sectors = max(conf->chunk_sectors,
7393                         conf->prev_chunk_sectors);
7394         }
7395         return err;
7396 }
7397
7398 static unsigned long raid5_cache_scan(struct shrinker *shrink,
7399                                       struct shrink_control *sc)
7400 {
7401         struct r5conf *conf = shrink->private_data;
7402         unsigned long ret = SHRINK_STOP;
7403
7404         if (mutex_trylock(&conf->cache_size_mutex)) {
7405                 ret= 0;
7406                 while (ret < sc->nr_to_scan &&
7407                        conf->max_nr_stripes > conf->min_nr_stripes) {
7408                         if (drop_one_stripe(conf) == 0) {
7409                                 ret = SHRINK_STOP;
7410                                 break;
7411                         }
7412                         ret++;
7413                 }
7414                 mutex_unlock(&conf->cache_size_mutex);
7415         }
7416         return ret;
7417 }
7418
7419 static unsigned long raid5_cache_count(struct shrinker *shrink,
7420                                        struct shrink_control *sc)
7421 {
7422         struct r5conf *conf = shrink->private_data;
7423         int max_stripes = READ_ONCE(conf->max_nr_stripes);
7424         int min_stripes = READ_ONCE(conf->min_nr_stripes);
7425
7426         if (max_stripes < min_stripes)
7427                 /* unlikely, but not impossible */
7428                 return 0;
7429         return max_stripes - min_stripes;
7430 }
7431
7432 static struct r5conf *setup_conf(struct mddev *mddev)
7433 {
7434         struct r5conf *conf;
7435         int raid_disk, memory, max_disks;
7436         struct md_rdev *rdev;
7437         struct disk_info *disk;
7438         char pers_name[6];
7439         int i;
7440         int group_cnt;
7441         struct r5worker_group *new_group;
7442         int ret = -ENOMEM;
7443
7444         if (mddev->new_level != 5
7445             && mddev->new_level != 4
7446             && mddev->new_level != 6) {
7447                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
7448                         mdname(mddev), mddev->new_level);
7449                 return ERR_PTR(-EIO);
7450         }
7451         if ((mddev->new_level == 5
7452              && !algorithm_valid_raid5(mddev->new_layout)) ||
7453             (mddev->new_level == 6
7454              && !algorithm_valid_raid6(mddev->new_layout))) {
7455                 pr_warn("md/raid:%s: layout %d not supported\n",
7456                         mdname(mddev), mddev->new_layout);
7457                 return ERR_PTR(-EIO);
7458         }
7459         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
7460                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
7461                         mdname(mddev), mddev->raid_disks);
7462                 return ERR_PTR(-EINVAL);
7463         }
7464
7465         if (!mddev->new_chunk_sectors ||
7466             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
7467             !is_power_of_2(mddev->new_chunk_sectors)) {
7468                 pr_warn("md/raid:%s: invalid chunk size %d\n",
7469                         mdname(mddev), mddev->new_chunk_sectors << 9);
7470                 return ERR_PTR(-EINVAL);
7471         }
7472
7473         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
7474         if (conf == NULL)
7475                 goto abort;
7476
7477 #if PAGE_SIZE != DEFAULT_STRIPE_SIZE
7478         conf->stripe_size = DEFAULT_STRIPE_SIZE;
7479         conf->stripe_shift = ilog2(DEFAULT_STRIPE_SIZE) - 9;
7480         conf->stripe_sectors = DEFAULT_STRIPE_SIZE >> 9;
7481 #endif
7482         INIT_LIST_HEAD(&conf->free_list);
7483         INIT_LIST_HEAD(&conf->pending_list);
7484         conf->pending_data = kcalloc(PENDING_IO_MAX,
7485                                      sizeof(struct r5pending_data),
7486                                      GFP_KERNEL);
7487         if (!conf->pending_data)
7488                 goto abort;
7489         for (i = 0; i < PENDING_IO_MAX; i++)
7490                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
7491         /* Don't enable multi-threading by default*/
7492         if (!alloc_thread_groups(conf, 0, &group_cnt, &new_group)) {
7493                 conf->group_cnt = group_cnt;
7494                 conf->worker_cnt_per_group = 0;
7495                 conf->worker_groups = new_group;
7496         } else
7497                 goto abort;
7498         spin_lock_init(&conf->device_lock);
7499         seqcount_spinlock_init(&conf->gen_lock, &conf->device_lock);
7500         mutex_init(&conf->cache_size_mutex);
7501
7502         init_waitqueue_head(&conf->wait_for_quiescent);
7503         init_waitqueue_head(&conf->wait_for_stripe);
7504         init_waitqueue_head(&conf->wait_for_reshape);
7505         INIT_LIST_HEAD(&conf->handle_list);
7506         INIT_LIST_HEAD(&conf->loprio_list);
7507         INIT_LIST_HEAD(&conf->hold_list);
7508         INIT_LIST_HEAD(&conf->delayed_list);
7509         INIT_LIST_HEAD(&conf->bitmap_list);
7510         init_llist_head(&conf->released_stripes);
7511         atomic_set(&conf->active_stripes, 0);
7512         atomic_set(&conf->preread_active_stripes, 0);
7513         atomic_set(&conf->active_aligned_reads, 0);
7514         spin_lock_init(&conf->pending_bios_lock);
7515         conf->batch_bio_dispatch = true;
7516         rdev_for_each(rdev, mddev) {
7517                 if (test_bit(Journal, &rdev->flags))
7518                         continue;
7519                 if (bdev_nonrot(rdev->bdev)) {
7520                         conf->batch_bio_dispatch = false;
7521                         break;
7522                 }
7523         }
7524
7525         conf->bypass_threshold = BYPASS_THRESHOLD;
7526         conf->recovery_disabled = mddev->recovery_disabled - 1;
7527
7528         conf->raid_disks = mddev->raid_disks;
7529         if (mddev->reshape_position == MaxSector)
7530                 conf->previous_raid_disks = mddev->raid_disks;
7531         else
7532                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
7533         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
7534
7535         conf->disks = kcalloc(max_disks, sizeof(struct disk_info),
7536                               GFP_KERNEL);
7537
7538         if (!conf->disks)
7539                 goto abort;
7540
7541         for (i = 0; i < max_disks; i++) {
7542                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
7543                 if (!conf->disks[i].extra_page)
7544                         goto abort;
7545         }
7546
7547         ret = bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0);
7548         if (ret)
7549                 goto abort;
7550         conf->mddev = mddev;
7551
7552         ret = -ENOMEM;
7553         conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL);
7554         if (!conf->stripe_hashtbl)
7555                 goto abort;
7556
7557         /* We init hash_locks[0] separately to that it can be used
7558          * as the reference lock in the spin_lock_nest_lock() call
7559          * in lock_all_device_hash_locks_irq in order to convince
7560          * lockdep that we know what we are doing.
7561          */
7562         spin_lock_init(conf->hash_locks);
7563         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
7564                 spin_lock_init(conf->hash_locks + i);
7565
7566         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7567                 INIT_LIST_HEAD(conf->inactive_list + i);
7568
7569         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
7570                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
7571
7572         atomic_set(&conf->r5c_cached_full_stripes, 0);
7573         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
7574         atomic_set(&conf->r5c_cached_partial_stripes, 0);
7575         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
7576         atomic_set(&conf->r5c_flushing_full_stripes, 0);
7577         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
7578
7579         conf->level = mddev->new_level;
7580         conf->chunk_sectors = mddev->new_chunk_sectors;
7581         ret = raid5_alloc_percpu(conf);
7582         if (ret)
7583                 goto abort;
7584
7585         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
7586
7587         ret = -EIO;
7588         rdev_for_each(rdev, mddev) {
7589                 raid_disk = rdev->raid_disk;
7590                 if (raid_disk >= max_disks
7591                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
7592                         continue;
7593                 disk = conf->disks + raid_disk;
7594
7595                 if (test_bit(Replacement, &rdev->flags)) {
7596                         if (disk->replacement)
7597                                 goto abort;
7598                         disk->replacement = rdev;
7599                 } else {
7600                         if (disk->rdev)
7601                                 goto abort;
7602                         disk->rdev = rdev;
7603                 }
7604
7605                 if (test_bit(In_sync, &rdev->flags)) {
7606                         pr_info("md/raid:%s: device %pg operational as raid disk %d\n",
7607                                 mdname(mddev), rdev->bdev, raid_disk);
7608                 } else if (rdev->saved_raid_disk != raid_disk)
7609                         /* Cannot rely on bitmap to complete recovery */
7610                         conf->fullsync = 1;
7611         }
7612
7613         conf->level = mddev->new_level;
7614         if (conf->level == 6) {
7615                 conf->max_degraded = 2;
7616                 if (raid6_call.xor_syndrome)
7617                         conf->rmw_level = PARITY_ENABLE_RMW;
7618                 else
7619                         conf->rmw_level = PARITY_DISABLE_RMW;
7620         } else {
7621                 conf->max_degraded = 1;
7622                 conf->rmw_level = PARITY_ENABLE_RMW;
7623         }
7624         conf->algorithm = mddev->new_layout;
7625         conf->reshape_progress = mddev->reshape_position;
7626         if (conf->reshape_progress != MaxSector) {
7627                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7628                 conf->prev_algo = mddev->layout;
7629         } else {
7630                 conf->prev_chunk_sectors = conf->chunk_sectors;
7631                 conf->prev_algo = conf->algorithm;
7632         }
7633
7634         conf->min_nr_stripes = NR_STRIPES;
7635         if (mddev->reshape_position != MaxSector) {
7636                 int stripes = max_t(int,
7637                         ((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4,
7638                         ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4);
7639                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7640                 if (conf->min_nr_stripes != NR_STRIPES)
7641                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7642                                 mdname(mddev), conf->min_nr_stripes);
7643         }
7644         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7645                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7646         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7647         if (grow_stripes(conf, conf->min_nr_stripes)) {
7648                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7649                         mdname(mddev), memory);
7650                 ret = -ENOMEM;
7651                 goto abort;
7652         } else
7653                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7654         /*
7655          * Losing a stripe head costs more than the time to refill it,
7656          * it reduces the queue depth and so can hurt throughput.
7657          * So set it rather large, scaled by number of devices.
7658          */
7659         conf->shrinker = shrinker_alloc(0, "md-raid5:%s", mdname(mddev));
7660         if (!conf->shrinker) {
7661                 ret = -ENOMEM;
7662                 pr_warn("md/raid:%s: couldn't allocate shrinker.\n",
7663                         mdname(mddev));
7664                 goto abort;
7665         }
7666
7667         conf->shrinker->seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7668         conf->shrinker->scan_objects = raid5_cache_scan;
7669         conf->shrinker->count_objects = raid5_cache_count;
7670         conf->shrinker->batch = 128;
7671         conf->shrinker->private_data = conf;
7672
7673         shrinker_register(conf->shrinker);
7674
7675         sprintf(pers_name, "raid%d", mddev->new_level);
7676         rcu_assign_pointer(conf->thread,
7677                            md_register_thread(raid5d, mddev, pers_name));
7678         if (!conf->thread) {
7679                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7680                         mdname(mddev));
7681                 ret = -ENOMEM;
7682                 goto abort;
7683         }
7684
7685         return conf;
7686
7687  abort:
7688         if (conf)
7689                 free_conf(conf);
7690         return ERR_PTR(ret);
7691 }
7692
7693 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7694 {
7695         switch (algo) {
7696         case ALGORITHM_PARITY_0:
7697                 if (raid_disk < max_degraded)
7698                         return 1;
7699                 break;
7700         case ALGORITHM_PARITY_N:
7701                 if (raid_disk >= raid_disks - max_degraded)
7702                         return 1;
7703                 break;
7704         case ALGORITHM_PARITY_0_6:
7705                 if (raid_disk == 0 ||
7706                     raid_disk == raid_disks - 1)
7707                         return 1;
7708                 break;
7709         case ALGORITHM_LEFT_ASYMMETRIC_6:
7710         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7711         case ALGORITHM_LEFT_SYMMETRIC_6:
7712         case ALGORITHM_RIGHT_SYMMETRIC_6:
7713                 if (raid_disk == raid_disks - 1)
7714                         return 1;
7715         }
7716         return 0;
7717 }
7718
7719 static int raid5_set_limits(struct mddev *mddev)
7720 {
7721         struct r5conf *conf = mddev->private;
7722         struct queue_limits lim;
7723         int data_disks, stripe;
7724         struct md_rdev *rdev;
7725
7726         /*
7727          * The read-ahead size must cover two whole stripes, which is
7728          * 2 * (datadisks) * chunksize where 'n' is the number of raid devices.
7729          */
7730         data_disks = conf->previous_raid_disks - conf->max_degraded;
7731
7732         /*
7733          * We can only discard a whole stripe. It doesn't make sense to
7734          * discard data disk but write parity disk
7735          */
7736         stripe = roundup_pow_of_two(data_disks * (mddev->chunk_sectors << 9));
7737
7738         md_init_stacking_limits(&lim);
7739         lim.io_min = mddev->chunk_sectors << 9;
7740         lim.io_opt = lim.io_min * (conf->raid_disks - conf->max_degraded);
7741         lim.features |= BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE;
7742         lim.discard_granularity = stripe;
7743         lim.max_write_zeroes_sectors = 0;
7744         mddev_stack_rdev_limits(mddev, &lim, 0);
7745         rdev_for_each(rdev, mddev)
7746                 queue_limits_stack_bdev(&lim, rdev->bdev, rdev->new_data_offset,
7747                                 mddev->gendisk->disk_name);
7748
7749         /*
7750          * Zeroing is required for discard, otherwise data could be lost.
7751          *
7752          * Consider a scenario: discard a stripe (the stripe could be
7753          * inconsistent if discard_zeroes_data is 0); write one disk of the
7754          * stripe (the stripe could be inconsistent again depending on which
7755          * disks are used to calculate parity); the disk is broken; The stripe
7756          * data of this disk is lost.
7757          *
7758          * We only allow DISCARD if the sysadmin has confirmed that only safe
7759          * devices are in use by setting a module parameter.  A better idea
7760          * might be to turn DISCARD into WRITE_ZEROES requests, as that is
7761          * required to be safe.
7762          */
7763         if (!devices_handle_discard_safely ||
7764             lim.max_discard_sectors < (stripe >> 9) ||
7765             lim.discard_granularity < stripe)
7766                 lim.max_hw_discard_sectors = 0;
7767
7768         /*
7769          * Requests require having a bitmap for each stripe.
7770          * Limit the max sectors based on this.
7771          */
7772         lim.max_hw_sectors = RAID5_MAX_REQ_STRIPES << RAID5_STRIPE_SHIFT(conf);
7773
7774         /* No restrictions on the number of segments in the request */
7775         lim.max_segments = USHRT_MAX;
7776
7777         return queue_limits_set(mddev->gendisk->queue, &lim);
7778 }
7779
7780 static int raid5_run(struct mddev *mddev)
7781 {
7782         struct r5conf *conf;
7783         int dirty_parity_disks = 0;
7784         struct md_rdev *rdev;
7785         struct md_rdev *journal_dev = NULL;
7786         sector_t reshape_offset = 0;
7787         int i;
7788         long long min_offset_diff = 0;
7789         int first = 1;
7790         int ret = -EIO;
7791
7792         if (mddev->recovery_cp != MaxSector)
7793                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7794                           mdname(mddev));
7795
7796         rdev_for_each(rdev, mddev) {
7797                 long long diff;
7798
7799                 if (test_bit(Journal, &rdev->flags)) {
7800                         journal_dev = rdev;
7801                         continue;
7802                 }
7803                 if (rdev->raid_disk < 0)
7804                         continue;
7805                 diff = (rdev->new_data_offset - rdev->data_offset);
7806                 if (first) {
7807                         min_offset_diff = diff;
7808                         first = 0;
7809                 } else if (mddev->reshape_backwards &&
7810                          diff < min_offset_diff)
7811                         min_offset_diff = diff;
7812                 else if (!mddev->reshape_backwards &&
7813                          diff > min_offset_diff)
7814                         min_offset_diff = diff;
7815         }
7816
7817         if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7818             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7819                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7820                           mdname(mddev));
7821                 return -EINVAL;
7822         }
7823
7824         if (mddev->reshape_position != MaxSector) {
7825                 /* Check that we can continue the reshape.
7826                  * Difficulties arise if the stripe we would write to
7827                  * next is at or after the stripe we would read from next.
7828                  * For a reshape that changes the number of devices, this
7829                  * is only possible for a very short time, and mdadm makes
7830                  * sure that time appears to have past before assembling
7831                  * the array.  So we fail if that time hasn't passed.
7832                  * For a reshape that keeps the number of devices the same
7833                  * mdadm must be monitoring the reshape can keeping the
7834                  * critical areas read-only and backed up.  It will start
7835                  * the array in read-only mode, so we check for that.
7836                  */
7837                 sector_t here_new, here_old;
7838                 int old_disks;
7839                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7840                 int chunk_sectors;
7841                 int new_data_disks;
7842
7843                 if (journal_dev) {
7844                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7845                                 mdname(mddev));
7846                         return -EINVAL;
7847                 }
7848
7849                 if (mddev->new_level != mddev->level) {
7850                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7851                                 mdname(mddev));
7852                         return -EINVAL;
7853                 }
7854                 old_disks = mddev->raid_disks - mddev->delta_disks;
7855                 /* reshape_position must be on a new-stripe boundary, and one
7856                  * further up in new geometry must map after here in old
7857                  * geometry.
7858                  * If the chunk sizes are different, then as we perform reshape
7859                  * in units of the largest of the two, reshape_position needs
7860                  * be a multiple of the largest chunk size times new data disks.
7861                  */
7862                 here_new = mddev->reshape_position;
7863                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7864                 new_data_disks = mddev->raid_disks - max_degraded;
7865                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7866                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7867                                 mdname(mddev));
7868                         return -EINVAL;
7869                 }
7870                 reshape_offset = here_new * chunk_sectors;
7871                 /* here_new is the stripe we will write to */
7872                 here_old = mddev->reshape_position;
7873                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7874                 /* here_old is the first stripe that we might need to read
7875                  * from */
7876                 if (mddev->delta_disks == 0) {
7877                         /* We cannot be sure it is safe to start an in-place
7878                          * reshape.  It is only safe if user-space is monitoring
7879                          * and taking constant backups.
7880                          * mdadm always starts a situation like this in
7881                          * readonly mode so it can take control before
7882                          * allowing any writes.  So just check for that.
7883                          */
7884                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7885                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7886                                 /* not really in-place - so OK */;
7887                         else if (mddev->ro == 0) {
7888                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7889                                         mdname(mddev));
7890                                 return -EINVAL;
7891                         }
7892                 } else if (mddev->reshape_backwards
7893                     ? (here_new * chunk_sectors + min_offset_diff <=
7894                        here_old * chunk_sectors)
7895                     : (here_new * chunk_sectors >=
7896                        here_old * chunk_sectors + (-min_offset_diff))) {
7897                         /* Reading from the same stripe as writing to - bad */
7898                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7899                                 mdname(mddev));
7900                         return -EINVAL;
7901                 }
7902                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7903                 /* OK, we should be able to continue; */
7904         } else {
7905                 BUG_ON(mddev->level != mddev->new_level);
7906                 BUG_ON(mddev->layout != mddev->new_layout);
7907                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7908                 BUG_ON(mddev->delta_disks != 0);
7909         }
7910
7911         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7912             test_bit(MD_HAS_PPL, &mddev->flags)) {
7913                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7914                         mdname(mddev));
7915                 clear_bit(MD_HAS_PPL, &mddev->flags);
7916                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7917         }
7918
7919         if (mddev->private == NULL)
7920                 conf = setup_conf(mddev);
7921         else
7922                 conf = mddev->private;
7923
7924         if (IS_ERR(conf))
7925                 return PTR_ERR(conf);
7926
7927         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7928                 if (!journal_dev) {
7929                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7930                                 mdname(mddev));
7931                         mddev->ro = 1;
7932                         set_disk_ro(mddev->gendisk, 1);
7933                 } else if (mddev->recovery_cp == MaxSector)
7934                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7935         }
7936
7937         conf->min_offset_diff = min_offset_diff;
7938         rcu_assign_pointer(mddev->thread, conf->thread);
7939         rcu_assign_pointer(conf->thread, NULL);
7940         mddev->private = conf;
7941
7942         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7943              i++) {
7944                 rdev = conf->disks[i].rdev;
7945                 if (!rdev)
7946                         continue;
7947                 if (conf->disks[i].replacement &&
7948                     conf->reshape_progress != MaxSector) {
7949                         /* replacements and reshape simply do not mix. */
7950                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7951                         goto abort;
7952                 }
7953                 if (test_bit(In_sync, &rdev->flags))
7954                         continue;
7955                 /* This disc is not fully in-sync.  However if it
7956                  * just stored parity (beyond the recovery_offset),
7957                  * when we don't need to be concerned about the
7958                  * array being dirty.
7959                  * When reshape goes 'backwards', we never have
7960                  * partially completed devices, so we only need
7961                  * to worry about reshape going forwards.
7962                  */
7963                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7964                 if (mddev->major_version == 0 &&
7965                     mddev->minor_version > 90)
7966                         rdev->recovery_offset = reshape_offset;
7967
7968                 if (rdev->recovery_offset < reshape_offset) {
7969                         /* We need to check old and new layout */
7970                         if (!only_parity(rdev->raid_disk,
7971                                          conf->algorithm,
7972                                          conf->raid_disks,
7973                                          conf->max_degraded))
7974                                 continue;
7975                 }
7976                 if (!only_parity(rdev->raid_disk,
7977                                  conf->prev_algo,
7978                                  conf->previous_raid_disks,
7979                                  conf->max_degraded))
7980                         continue;
7981                 dirty_parity_disks++;
7982         }
7983
7984         /*
7985          * 0 for a fully functional array, 1 or 2 for a degraded array.
7986          */
7987         mddev->degraded = raid5_calc_degraded(conf);
7988
7989         if (has_failed(conf)) {
7990                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7991                         mdname(mddev), mddev->degraded, conf->raid_disks);
7992                 goto abort;
7993         }
7994
7995         /* device size must be a multiple of chunk size */
7996         mddev->dev_sectors &= ~((sector_t)mddev->chunk_sectors - 1);
7997         mddev->resync_max_sectors = mddev->dev_sectors;
7998
7999         if (mddev->degraded > dirty_parity_disks &&
8000             mddev->recovery_cp != MaxSector) {
8001                 if (test_bit(MD_HAS_PPL, &mddev->flags))
8002                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
8003                                 mdname(mddev));
8004                 else if (mddev->ok_start_degraded)
8005                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
8006                                 mdname(mddev));
8007                 else {
8008                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
8009                                 mdname(mddev));
8010                         goto abort;
8011                 }
8012         }
8013
8014         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
8015                 mdname(mddev), conf->level,
8016                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
8017                 mddev->new_layout);
8018
8019         print_raid5_conf(conf);
8020
8021         if (conf->reshape_progress != MaxSector) {
8022                 conf->reshape_safe = conf->reshape_progress;
8023                 atomic_set(&conf->reshape_stripes, 0);
8024                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8025                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8026                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8027                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8028         }
8029
8030         /* Ok, everything is just fine now */
8031         if (mddev->to_remove == &raid5_attrs_group)
8032                 mddev->to_remove = NULL;
8033         else if (mddev->kobj.sd &&
8034             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
8035                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
8036                         mdname(mddev));
8037         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
8038
8039         if (!mddev_is_dm(mddev)) {
8040                 ret = raid5_set_limits(mddev);
8041                 if (ret)
8042                         goto abort;
8043         }
8044
8045         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
8046                 goto abort;
8047
8048         return 0;
8049 abort:
8050         md_unregister_thread(mddev, &mddev->thread);
8051         print_raid5_conf(conf);
8052         free_conf(conf);
8053         mddev->private = NULL;
8054         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
8055         return ret;
8056 }
8057
8058 static void raid5_free(struct mddev *mddev, void *priv)
8059 {
8060         struct r5conf *conf = priv;
8061
8062         free_conf(conf);
8063         mddev->to_remove = &raid5_attrs_group;
8064 }
8065
8066 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
8067 {
8068         struct r5conf *conf = mddev->private;
8069         int i;
8070
8071         lockdep_assert_held(&mddev->lock);
8072
8073         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
8074                 conf->chunk_sectors / 2, mddev->layout);
8075         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
8076         for (i = 0; i < conf->raid_disks; i++) {
8077                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
8078
8079                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
8080         }
8081         seq_printf (seq, "]");
8082 }
8083
8084 static void print_raid5_conf(struct r5conf *conf)
8085 {
8086         struct md_rdev *rdev;
8087         int i;
8088
8089         pr_debug("RAID conf printout:\n");
8090         if (!conf) {
8091                 pr_debug("(conf==NULL)\n");
8092                 return;
8093         }
8094         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
8095                conf->raid_disks,
8096                conf->raid_disks - conf->mddev->degraded);
8097
8098         for (i = 0; i < conf->raid_disks; i++) {
8099                 rdev = conf->disks[i].rdev;
8100                 if (rdev)
8101                         pr_debug(" disk %d, o:%d, dev:%pg\n",
8102                                i, !test_bit(Faulty, &rdev->flags),
8103                                rdev->bdev);
8104         }
8105 }
8106
8107 static int raid5_spare_active(struct mddev *mddev)
8108 {
8109         int i;
8110         struct r5conf *conf = mddev->private;
8111         struct md_rdev *rdev, *replacement;
8112         int count = 0;
8113         unsigned long flags;
8114
8115         for (i = 0; i < conf->raid_disks; i++) {
8116                 rdev = conf->disks[i].rdev;
8117                 replacement = conf->disks[i].replacement;
8118                 if (replacement
8119                     && replacement->recovery_offset == MaxSector
8120                     && !test_bit(Faulty, &replacement->flags)
8121                     && !test_and_set_bit(In_sync, &replacement->flags)) {
8122                         /* Replacement has just become active. */
8123                         if (!rdev
8124                             || !test_and_clear_bit(In_sync, &rdev->flags))
8125                                 count++;
8126                         if (rdev) {
8127                                 /* Replaced device not technically faulty,
8128                                  * but we need to be sure it gets removed
8129                                  * and never re-added.
8130                                  */
8131                                 set_bit(Faulty, &rdev->flags);
8132                                 sysfs_notify_dirent_safe(
8133                                         rdev->sysfs_state);
8134                         }
8135                         sysfs_notify_dirent_safe(replacement->sysfs_state);
8136                 } else if (rdev
8137                     && rdev->recovery_offset == MaxSector
8138                     && !test_bit(Faulty, &rdev->flags)
8139                     && !test_and_set_bit(In_sync, &rdev->flags)) {
8140                         count++;
8141                         sysfs_notify_dirent_safe(rdev->sysfs_state);
8142                 }
8143         }
8144         spin_lock_irqsave(&conf->device_lock, flags);
8145         mddev->degraded = raid5_calc_degraded(conf);
8146         spin_unlock_irqrestore(&conf->device_lock, flags);
8147         print_raid5_conf(conf);
8148         return count;
8149 }
8150
8151 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
8152 {
8153         struct r5conf *conf = mddev->private;
8154         int err = 0;
8155         int number = rdev->raid_disk;
8156         struct md_rdev **rdevp;
8157         struct disk_info *p;
8158         struct md_rdev *tmp;
8159
8160         print_raid5_conf(conf);
8161         if (test_bit(Journal, &rdev->flags) && conf->log) {
8162                 /*
8163                  * we can't wait pending write here, as this is called in
8164                  * raid5d, wait will deadlock.
8165                  * neilb: there is no locking about new writes here,
8166                  * so this cannot be safe.
8167                  */
8168                 if (atomic_read(&conf->active_stripes) ||
8169                     atomic_read(&conf->r5c_cached_full_stripes) ||
8170                     atomic_read(&conf->r5c_cached_partial_stripes)) {
8171                         return -EBUSY;
8172                 }
8173                 log_exit(conf);
8174                 return 0;
8175         }
8176         if (unlikely(number >= conf->pool_size))
8177                 return 0;
8178         p = conf->disks + number;
8179         if (rdev == p->rdev)
8180                 rdevp = &p->rdev;
8181         else if (rdev == p->replacement)
8182                 rdevp = &p->replacement;
8183         else
8184                 return 0;
8185
8186         if (number >= conf->raid_disks &&
8187             conf->reshape_progress == MaxSector)
8188                 clear_bit(In_sync, &rdev->flags);
8189
8190         if (test_bit(In_sync, &rdev->flags) ||
8191             atomic_read(&rdev->nr_pending)) {
8192                 err = -EBUSY;
8193                 goto abort;
8194         }
8195         /* Only remove non-faulty devices if recovery
8196          * isn't possible.
8197          */
8198         if (!test_bit(Faulty, &rdev->flags) &&
8199             mddev->recovery_disabled != conf->recovery_disabled &&
8200             !has_failed(conf) &&
8201             (!p->replacement || p->replacement == rdev) &&
8202             number < conf->raid_disks) {
8203                 err = -EBUSY;
8204                 goto abort;
8205         }
8206         WRITE_ONCE(*rdevp, NULL);
8207         if (!err) {
8208                 err = log_modify(conf, rdev, false);
8209                 if (err)
8210                         goto abort;
8211         }
8212
8213         tmp = p->replacement;
8214         if (tmp) {
8215                 /* We must have just cleared 'rdev' */
8216                 WRITE_ONCE(p->rdev, tmp);
8217                 clear_bit(Replacement, &tmp->flags);
8218                 WRITE_ONCE(p->replacement, NULL);
8219
8220                 if (!err)
8221                         err = log_modify(conf, tmp, true);
8222         }
8223
8224         clear_bit(WantReplacement, &rdev->flags);
8225 abort:
8226
8227         print_raid5_conf(conf);
8228         return err;
8229 }
8230
8231 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
8232 {
8233         struct r5conf *conf = mddev->private;
8234         int ret, err = -EEXIST;
8235         int disk;
8236         struct disk_info *p;
8237         struct md_rdev *tmp;
8238         int first = 0;
8239         int last = conf->raid_disks - 1;
8240
8241         if (test_bit(Journal, &rdev->flags)) {
8242                 if (conf->log)
8243                         return -EBUSY;
8244
8245                 rdev->raid_disk = 0;
8246                 /*
8247                  * The array is in readonly mode if journal is missing, so no
8248                  * write requests running. We should be safe
8249                  */
8250                 ret = log_init(conf, rdev, false);
8251                 if (ret)
8252                         return ret;
8253
8254                 ret = r5l_start(conf->log);
8255                 if (ret)
8256                         return ret;
8257
8258                 return 0;
8259         }
8260         if (mddev->recovery_disabled == conf->recovery_disabled)
8261                 return -EBUSY;
8262
8263         if (rdev->saved_raid_disk < 0 && has_failed(conf))
8264                 /* no point adding a device */
8265                 return -EINVAL;
8266
8267         if (rdev->raid_disk >= 0)
8268                 first = last = rdev->raid_disk;
8269
8270         /*
8271          * find the disk ... but prefer rdev->saved_raid_disk
8272          * if possible.
8273          */
8274         if (rdev->saved_raid_disk >= first &&
8275             rdev->saved_raid_disk <= last &&
8276             conf->disks[rdev->saved_raid_disk].rdev == NULL)
8277                 first = rdev->saved_raid_disk;
8278
8279         for (disk = first; disk <= last; disk++) {
8280                 p = conf->disks + disk;
8281                 if (p->rdev == NULL) {
8282                         clear_bit(In_sync, &rdev->flags);
8283                         rdev->raid_disk = disk;
8284                         if (rdev->saved_raid_disk != disk)
8285                                 conf->fullsync = 1;
8286                         WRITE_ONCE(p->rdev, rdev);
8287
8288                         err = log_modify(conf, rdev, true);
8289
8290                         goto out;
8291                 }
8292         }
8293         for (disk = first; disk <= last; disk++) {
8294                 p = conf->disks + disk;
8295                 tmp = p->rdev;
8296                 if (test_bit(WantReplacement, &tmp->flags) &&
8297                     mddev->reshape_position == MaxSector &&
8298                     p->replacement == NULL) {
8299                         clear_bit(In_sync, &rdev->flags);
8300                         set_bit(Replacement, &rdev->flags);
8301                         rdev->raid_disk = disk;
8302                         err = 0;
8303                         conf->fullsync = 1;
8304                         WRITE_ONCE(p->replacement, rdev);
8305                         break;
8306                 }
8307         }
8308 out:
8309         print_raid5_conf(conf);
8310         return err;
8311 }
8312
8313 static int raid5_resize(struct mddev *mddev, sector_t sectors)
8314 {
8315         /* no resync is happening, and there is enough space
8316          * on all devices, so we can resize.
8317          * We need to make sure resync covers any new space.
8318          * If the array is shrinking we should possibly wait until
8319          * any io in the removed space completes, but it hardly seems
8320          * worth it.
8321          */
8322         sector_t newsize;
8323         struct r5conf *conf = mddev->private;
8324         int ret;
8325
8326         if (raid5_has_log(conf) || raid5_has_ppl(conf))
8327                 return -EINVAL;
8328         sectors &= ~((sector_t)conf->chunk_sectors - 1);
8329         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
8330         if (mddev->external_size &&
8331             mddev->array_sectors > newsize)
8332                 return -EINVAL;
8333
8334         ret = mddev->bitmap_ops->resize(mddev, sectors, 0, false);
8335         if (ret)
8336                 return ret;
8337
8338         md_set_array_sectors(mddev, newsize);
8339         if (sectors > mddev->dev_sectors &&
8340             mddev->recovery_cp > mddev->dev_sectors) {
8341                 mddev->recovery_cp = mddev->dev_sectors;
8342                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8343         }
8344         mddev->dev_sectors = sectors;
8345         mddev->resync_max_sectors = sectors;
8346         return 0;
8347 }
8348
8349 static int check_stripe_cache(struct mddev *mddev)
8350 {
8351         /* Can only proceed if there are plenty of stripe_heads.
8352          * We need a minimum of one full stripe,, and for sensible progress
8353          * it is best to have about 4 times that.
8354          * If we require 4 times, then the default 256 4K stripe_heads will
8355          * allow for chunk sizes up to 256K, which is probably OK.
8356          * If the chunk size is greater, user-space should request more
8357          * stripe_heads first.
8358          */
8359         struct r5conf *conf = mddev->private;
8360         if (((mddev->chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8361             > conf->min_nr_stripes ||
8362             ((mddev->new_chunk_sectors << 9) / RAID5_STRIPE_SIZE(conf)) * 4
8363             > conf->min_nr_stripes) {
8364                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
8365                         mdname(mddev),
8366                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
8367                          / RAID5_STRIPE_SIZE(conf))*4);
8368                 return 0;
8369         }
8370         return 1;
8371 }
8372
8373 static int check_reshape(struct mddev *mddev)
8374 {
8375         struct r5conf *conf = mddev->private;
8376
8377         if (raid5_has_log(conf) || raid5_has_ppl(conf))
8378                 return -EINVAL;
8379         if (mddev->delta_disks == 0 &&
8380             mddev->new_layout == mddev->layout &&
8381             mddev->new_chunk_sectors == mddev->chunk_sectors)
8382                 return 0; /* nothing to do */
8383         if (has_failed(conf))
8384                 return -EINVAL;
8385         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
8386                 /* We might be able to shrink, but the devices must
8387                  * be made bigger first.
8388                  * For raid6, 4 is the minimum size.
8389                  * Otherwise 2 is the minimum
8390                  */
8391                 int min = 2;
8392                 if (mddev->level == 6)
8393                         min = 4;
8394                 if (mddev->raid_disks + mddev->delta_disks < min)
8395                         return -EINVAL;
8396         }
8397
8398         if (!check_stripe_cache(mddev))
8399                 return -ENOSPC;
8400
8401         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
8402             mddev->delta_disks > 0)
8403                 if (resize_chunks(conf,
8404                                   conf->previous_raid_disks
8405                                   + max(0, mddev->delta_disks),
8406                                   max(mddev->new_chunk_sectors,
8407                                       mddev->chunk_sectors)
8408                             ) < 0)
8409                         return -ENOMEM;
8410
8411         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
8412                 return 0; /* never bother to shrink */
8413         return resize_stripes(conf, (conf->previous_raid_disks
8414                                      + mddev->delta_disks));
8415 }
8416
8417 static int raid5_start_reshape(struct mddev *mddev)
8418 {
8419         struct r5conf *conf = mddev->private;
8420         struct md_rdev *rdev;
8421         int spares = 0;
8422         int i;
8423         unsigned long flags;
8424
8425         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
8426                 return -EBUSY;
8427
8428         if (!check_stripe_cache(mddev))
8429                 return -ENOSPC;
8430
8431         if (has_failed(conf))
8432                 return -EINVAL;
8433
8434         /* raid5 can't handle concurrent reshape and recovery */
8435         if (mddev->recovery_cp < MaxSector)
8436                 return -EBUSY;
8437         for (i = 0; i < conf->raid_disks; i++)
8438                 if (conf->disks[i].replacement)
8439                         return -EBUSY;
8440
8441         rdev_for_each(rdev, mddev) {
8442                 if (!test_bit(In_sync, &rdev->flags)
8443                     && !test_bit(Faulty, &rdev->flags))
8444                         spares++;
8445         }
8446
8447         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
8448                 /* Not enough devices even to make a degraded array
8449                  * of that size
8450                  */
8451                 return -EINVAL;
8452
8453         /* Refuse to reduce size of the array.  Any reductions in
8454          * array size must be through explicit setting of array_size
8455          * attribute.
8456          */
8457         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
8458             < mddev->array_sectors) {
8459                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
8460                         mdname(mddev));
8461                 return -EINVAL;
8462         }
8463
8464         atomic_set(&conf->reshape_stripes, 0);
8465         spin_lock_irq(&conf->device_lock);
8466         write_seqcount_begin(&conf->gen_lock);
8467         conf->previous_raid_disks = conf->raid_disks;
8468         conf->raid_disks += mddev->delta_disks;
8469         conf->prev_chunk_sectors = conf->chunk_sectors;
8470         conf->chunk_sectors = mddev->new_chunk_sectors;
8471         conf->prev_algo = conf->algorithm;
8472         conf->algorithm = mddev->new_layout;
8473         conf->generation++;
8474         /* Code that selects data_offset needs to see the generation update
8475          * if reshape_progress has been set - so a memory barrier needed.
8476          */
8477         smp_mb();
8478         if (mddev->reshape_backwards)
8479                 conf->reshape_progress = raid5_size(mddev, 0, 0);
8480         else
8481                 conf->reshape_progress = 0;
8482         conf->reshape_safe = conf->reshape_progress;
8483         write_seqcount_end(&conf->gen_lock);
8484         spin_unlock_irq(&conf->device_lock);
8485
8486         /* Now make sure any requests that proceeded on the assumption
8487          * the reshape wasn't running - like Discard or Read - have
8488          * completed.
8489          */
8490         raid5_quiesce(mddev, true);
8491         raid5_quiesce(mddev, false);
8492
8493         /* Add some new drives, as many as will fit.
8494          * We know there are enough to make the newly sized array work.
8495          * Don't add devices if we are reducing the number of
8496          * devices in the array.  This is because it is not possible
8497          * to correctly record the "partially reconstructed" state of
8498          * such devices during the reshape and confusion could result.
8499          */
8500         if (mddev->delta_disks >= 0) {
8501                 rdev_for_each(rdev, mddev)
8502                         if (rdev->raid_disk < 0 &&
8503                             !test_bit(Faulty, &rdev->flags)) {
8504                                 if (raid5_add_disk(mddev, rdev) == 0) {
8505                                         if (rdev->raid_disk
8506                                             >= conf->previous_raid_disks)
8507                                                 set_bit(In_sync, &rdev->flags);
8508                                         else
8509                                                 rdev->recovery_offset = 0;
8510
8511                                         /* Failure here is OK */
8512                                         sysfs_link_rdev(mddev, rdev);
8513                                 }
8514                         } else if (rdev->raid_disk >= conf->previous_raid_disks
8515                                    && !test_bit(Faulty, &rdev->flags)) {
8516                                 /* This is a spare that was manually added */
8517                                 set_bit(In_sync, &rdev->flags);
8518                         }
8519
8520                 /* When a reshape changes the number of devices,
8521                  * ->degraded is measured against the larger of the
8522                  * pre and post number of devices.
8523                  */
8524                 spin_lock_irqsave(&conf->device_lock, flags);
8525                 mddev->degraded = raid5_calc_degraded(conf);
8526                 spin_unlock_irqrestore(&conf->device_lock, flags);
8527         }
8528         mddev->raid_disks = conf->raid_disks;
8529         mddev->reshape_position = conf->reshape_progress;
8530         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8531
8532         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
8533         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
8534         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
8535         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
8536         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8537         conf->reshape_checkpoint = jiffies;
8538         md_new_event();
8539         return 0;
8540 }
8541
8542 /* This is called from the reshape thread and should make any
8543  * changes needed in 'conf'
8544  */
8545 static void end_reshape(struct r5conf *conf)
8546 {
8547
8548         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
8549                 struct md_rdev *rdev;
8550
8551                 spin_lock_irq(&conf->device_lock);
8552                 conf->previous_raid_disks = conf->raid_disks;
8553                 md_finish_reshape(conf->mddev);
8554                 smp_wmb();
8555                 conf->reshape_progress = MaxSector;
8556                 conf->mddev->reshape_position = MaxSector;
8557                 rdev_for_each(rdev, conf->mddev)
8558                         if (rdev->raid_disk >= 0 &&
8559                             !test_bit(Journal, &rdev->flags) &&
8560                             !test_bit(In_sync, &rdev->flags))
8561                                 rdev->recovery_offset = MaxSector;
8562                 spin_unlock_irq(&conf->device_lock);
8563                 wake_up(&conf->wait_for_reshape);
8564
8565                 mddev_update_io_opt(conf->mddev,
8566                         conf->raid_disks - conf->max_degraded);
8567         }
8568 }
8569
8570 /* This is called from the raid5d thread with mddev_lock held.
8571  * It makes config changes to the device.
8572  */
8573 static void raid5_finish_reshape(struct mddev *mddev)
8574 {
8575         struct r5conf *conf = mddev->private;
8576         struct md_rdev *rdev;
8577
8578         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8579
8580                 if (mddev->delta_disks <= 0) {
8581                         int d;
8582                         spin_lock_irq(&conf->device_lock);
8583                         mddev->degraded = raid5_calc_degraded(conf);
8584                         spin_unlock_irq(&conf->device_lock);
8585                         for (d = conf->raid_disks ;
8586                              d < conf->raid_disks - mddev->delta_disks;
8587                              d++) {
8588                                 rdev = conf->disks[d].rdev;
8589                                 if (rdev)
8590                                         clear_bit(In_sync, &rdev->flags);
8591                                 rdev = conf->disks[d].replacement;
8592                                 if (rdev)
8593                                         clear_bit(In_sync, &rdev->flags);
8594                         }
8595                 }
8596                 mddev->layout = conf->algorithm;
8597                 mddev->chunk_sectors = conf->chunk_sectors;
8598                 mddev->reshape_position = MaxSector;
8599                 mddev->delta_disks = 0;
8600                 mddev->reshape_backwards = 0;
8601         }
8602 }
8603
8604 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8605 {
8606         struct r5conf *conf = mddev->private;
8607
8608         if (quiesce) {
8609                 /* stop all writes */
8610                 lock_all_device_hash_locks_irq(conf);
8611                 /* '2' tells resync/reshape to pause so that all
8612                  * active stripes can drain
8613                  */
8614                 r5c_flush_cache(conf, INT_MAX);
8615                 /* need a memory barrier to make sure read_one_chunk() sees
8616                  * quiesce started and reverts to slow (locked) path.
8617                  */
8618                 smp_store_release(&conf->quiesce, 2);
8619                 wait_event_cmd(conf->wait_for_quiescent,
8620                                     atomic_read(&conf->active_stripes) == 0 &&
8621                                     atomic_read(&conf->active_aligned_reads) == 0,
8622                                     unlock_all_device_hash_locks_irq(conf),
8623                                     lock_all_device_hash_locks_irq(conf));
8624                 conf->quiesce = 1;
8625                 unlock_all_device_hash_locks_irq(conf);
8626                 /* allow reshape to continue */
8627                 wake_up(&conf->wait_for_reshape);
8628         } else {
8629                 /* re-enable writes */
8630                 lock_all_device_hash_locks_irq(conf);
8631                 conf->quiesce = 0;
8632                 wake_up(&conf->wait_for_quiescent);
8633                 wake_up(&conf->wait_for_reshape);
8634                 unlock_all_device_hash_locks_irq(conf);
8635         }
8636         log_quiesce(conf, quiesce);
8637 }
8638
8639 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8640 {
8641         struct r0conf *raid0_conf = mddev->private;
8642         sector_t sectors;
8643
8644         /* for raid0 takeover only one zone is supported */
8645         if (raid0_conf->nr_strip_zones > 1) {
8646                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8647                         mdname(mddev));
8648                 return ERR_PTR(-EINVAL);
8649         }
8650
8651         sectors = raid0_conf->strip_zone[0].zone_end;
8652         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8653         mddev->dev_sectors = sectors;
8654         mddev->new_level = level;
8655         mddev->new_layout = ALGORITHM_PARITY_N;
8656         mddev->new_chunk_sectors = mddev->chunk_sectors;
8657         mddev->raid_disks += 1;
8658         mddev->delta_disks = 1;
8659         /* make sure it will be not marked as dirty */
8660         mddev->recovery_cp = MaxSector;
8661
8662         return setup_conf(mddev);
8663 }
8664
8665 static void *raid5_takeover_raid1(struct mddev *mddev)
8666 {
8667         int chunksect;
8668         void *ret;
8669
8670         if (mddev->raid_disks != 2 ||
8671             mddev->degraded > 1)
8672                 return ERR_PTR(-EINVAL);
8673
8674         /* Should check if there are write-behind devices? */
8675
8676         chunksect = 64*2; /* 64K by default */
8677
8678         /* The array must be an exact multiple of chunksize */
8679         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8680                 chunksect >>= 1;
8681
8682         if ((chunksect<<9) < RAID5_STRIPE_SIZE((struct r5conf *)mddev->private))
8683                 /* array size does not allow a suitable chunk size */
8684                 return ERR_PTR(-EINVAL);
8685
8686         mddev->new_level = 5;
8687         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8688         mddev->new_chunk_sectors = chunksect;
8689
8690         ret = setup_conf(mddev);
8691         if (!IS_ERR(ret))
8692                 mddev_clear_unsupported_flags(mddev,
8693                         UNSUPPORTED_MDDEV_FLAGS);
8694         return ret;
8695 }
8696
8697 static void *raid5_takeover_raid6(struct mddev *mddev)
8698 {
8699         int new_layout;
8700
8701         switch (mddev->layout) {
8702         case ALGORITHM_LEFT_ASYMMETRIC_6:
8703                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8704                 break;
8705         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8706                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8707                 break;
8708         case ALGORITHM_LEFT_SYMMETRIC_6:
8709                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8710                 break;
8711         case ALGORITHM_RIGHT_SYMMETRIC_6:
8712                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8713                 break;
8714         case ALGORITHM_PARITY_0_6:
8715                 new_layout = ALGORITHM_PARITY_0;
8716                 break;
8717         case ALGORITHM_PARITY_N:
8718                 new_layout = ALGORITHM_PARITY_N;
8719                 break;
8720         default:
8721                 return ERR_PTR(-EINVAL);
8722         }
8723         mddev->new_level = 5;
8724         mddev->new_layout = new_layout;
8725         mddev->delta_disks = -1;
8726         mddev->raid_disks -= 1;
8727         return setup_conf(mddev);
8728 }
8729
8730 static int raid5_check_reshape(struct mddev *mddev)
8731 {
8732         /* For a 2-drive array, the layout and chunk size can be changed
8733          * immediately as not restriping is needed.
8734          * For larger arrays we record the new value - after validation
8735          * to be used by a reshape pass.
8736          */
8737         struct r5conf *conf = mddev->private;
8738         int new_chunk = mddev->new_chunk_sectors;
8739
8740         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8741                 return -EINVAL;
8742         if (new_chunk > 0) {
8743                 if (!is_power_of_2(new_chunk))
8744                         return -EINVAL;
8745                 if (new_chunk < (PAGE_SIZE>>9))
8746                         return -EINVAL;
8747                 if (mddev->array_sectors & (new_chunk-1))
8748                         /* not factor of array size */
8749                         return -EINVAL;
8750         }
8751
8752         /* They look valid */
8753
8754         if (mddev->raid_disks == 2) {
8755                 /* can make the change immediately */
8756                 if (mddev->new_layout >= 0) {
8757                         conf->algorithm = mddev->new_layout;
8758                         mddev->layout = mddev->new_layout;
8759                 }
8760                 if (new_chunk > 0) {
8761                         conf->chunk_sectors = new_chunk ;
8762                         mddev->chunk_sectors = new_chunk;
8763                 }
8764                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8765                 md_wakeup_thread(mddev->thread);
8766         }
8767         return check_reshape(mddev);
8768 }
8769
8770 static int raid6_check_reshape(struct mddev *mddev)
8771 {
8772         int new_chunk = mddev->new_chunk_sectors;
8773
8774         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8775                 return -EINVAL;
8776         if (new_chunk > 0) {
8777                 if (!is_power_of_2(new_chunk))
8778                         return -EINVAL;
8779                 if (new_chunk < (PAGE_SIZE >> 9))
8780                         return -EINVAL;
8781                 if (mddev->array_sectors & (new_chunk-1))
8782                         /* not factor of array size */
8783                         return -EINVAL;
8784         }
8785
8786         /* They look valid */
8787         return check_reshape(mddev);
8788 }
8789
8790 static void *raid5_takeover(struct mddev *mddev)
8791 {
8792         /* raid5 can take over:
8793          *  raid0 - if there is only one strip zone - make it a raid4 layout
8794          *  raid1 - if there are two drives.  We need to know the chunk size
8795          *  raid4 - trivial - just use a raid4 layout.
8796          *  raid6 - Providing it is a *_6 layout
8797          */
8798         if (mddev->level == 0)
8799                 return raid45_takeover_raid0(mddev, 5);
8800         if (mddev->level == 1)
8801                 return raid5_takeover_raid1(mddev);
8802         if (mddev->level == 4) {
8803                 mddev->new_layout = ALGORITHM_PARITY_N;
8804                 mddev->new_level = 5;
8805                 return setup_conf(mddev);
8806         }
8807         if (mddev->level == 6)
8808                 return raid5_takeover_raid6(mddev);
8809
8810         return ERR_PTR(-EINVAL);
8811 }
8812
8813 static void *raid4_takeover(struct mddev *mddev)
8814 {
8815         /* raid4 can take over:
8816          *  raid0 - if there is only one strip zone
8817          *  raid5 - if layout is right
8818          */
8819         if (mddev->level == 0)
8820                 return raid45_takeover_raid0(mddev, 4);
8821         if (mddev->level == 5 &&
8822             mddev->layout == ALGORITHM_PARITY_N) {
8823                 mddev->new_layout = 0;
8824                 mddev->new_level = 4;
8825                 return setup_conf(mddev);
8826         }
8827         return ERR_PTR(-EINVAL);
8828 }
8829
8830 static struct md_personality raid5_personality;
8831
8832 static void *raid6_takeover(struct mddev *mddev)
8833 {
8834         /* Currently can only take over a raid5.  We map the
8835          * personality to an equivalent raid6 personality
8836          * with the Q block at the end.
8837          */
8838         int new_layout;
8839
8840         if (mddev->pers != &raid5_personality)
8841                 return ERR_PTR(-EINVAL);
8842         if (mddev->degraded > 1)
8843                 return ERR_PTR(-EINVAL);
8844         if (mddev->raid_disks > 253)
8845                 return ERR_PTR(-EINVAL);
8846         if (mddev->raid_disks < 3)
8847                 return ERR_PTR(-EINVAL);
8848
8849         switch (mddev->layout) {
8850         case ALGORITHM_LEFT_ASYMMETRIC:
8851                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8852                 break;
8853         case ALGORITHM_RIGHT_ASYMMETRIC:
8854                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8855                 break;
8856         case ALGORITHM_LEFT_SYMMETRIC:
8857                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8858                 break;
8859         case ALGORITHM_RIGHT_SYMMETRIC:
8860                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8861                 break;
8862         case ALGORITHM_PARITY_0:
8863                 new_layout = ALGORITHM_PARITY_0_6;
8864                 break;
8865         case ALGORITHM_PARITY_N:
8866                 new_layout = ALGORITHM_PARITY_N;
8867                 break;
8868         default:
8869                 return ERR_PTR(-EINVAL);
8870         }
8871         mddev->new_level = 6;
8872         mddev->new_layout = new_layout;
8873         mddev->delta_disks = 1;
8874         mddev->raid_disks += 1;
8875         return setup_conf(mddev);
8876 }
8877
8878 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8879 {
8880         struct r5conf *conf;
8881         int err;
8882
8883         err = mddev_suspend_and_lock(mddev);
8884         if (err)
8885                 return err;
8886         conf = mddev->private;
8887         if (!conf) {
8888                 mddev_unlock_and_resume(mddev);
8889                 return -ENODEV;
8890         }
8891
8892         if (strncmp(buf, "ppl", 3) == 0) {
8893                 /* ppl only works with RAID 5 */
8894                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8895                         err = log_init(conf, NULL, true);
8896                         if (!err) {
8897                                 err = resize_stripes(conf, conf->pool_size);
8898                                 if (err)
8899                                         log_exit(conf);
8900                         }
8901                 } else
8902                         err = -EINVAL;
8903         } else if (strncmp(buf, "resync", 6) == 0) {
8904                 if (raid5_has_ppl(conf)) {
8905                         log_exit(conf);
8906                         err = resize_stripes(conf, conf->pool_size);
8907                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8908                            r5l_log_disk_error(conf)) {
8909                         bool journal_dev_exists = false;
8910                         struct md_rdev *rdev;
8911
8912                         rdev_for_each(rdev, mddev)
8913                                 if (test_bit(Journal, &rdev->flags)) {
8914                                         journal_dev_exists = true;
8915                                         break;
8916                                 }
8917
8918                         if (!journal_dev_exists)
8919                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8920                         else  /* need remove journal device first */
8921                                 err = -EBUSY;
8922                 } else
8923                         err = -EINVAL;
8924         } else {
8925                 err = -EINVAL;
8926         }
8927
8928         if (!err)
8929                 md_update_sb(mddev, 1);
8930
8931         mddev_unlock_and_resume(mddev);
8932
8933         return err;
8934 }
8935
8936 static int raid5_start(struct mddev *mddev)
8937 {
8938         struct r5conf *conf = mddev->private;
8939
8940         return r5l_start(conf->log);
8941 }
8942
8943 /*
8944  * This is only used for dm-raid456, caller already frozen sync_thread, hence
8945  * if rehsape is still in progress, io that is waiting for reshape can never be
8946  * done now, hence wake up and handle those IO.
8947  */
8948 static void raid5_prepare_suspend(struct mddev *mddev)
8949 {
8950         struct r5conf *conf = mddev->private;
8951
8952         wake_up(&conf->wait_for_reshape);
8953 }
8954
8955 static struct md_personality raid6_personality =
8956 {
8957         .name           = "raid6",
8958         .level          = 6,
8959         .owner          = THIS_MODULE,
8960         .make_request   = raid5_make_request,
8961         .run            = raid5_run,
8962         .start          = raid5_start,
8963         .free           = raid5_free,
8964         .status         = raid5_status,
8965         .error_handler  = raid5_error,
8966         .hot_add_disk   = raid5_add_disk,
8967         .hot_remove_disk= raid5_remove_disk,
8968         .spare_active   = raid5_spare_active,
8969         .sync_request   = raid5_sync_request,
8970         .resize         = raid5_resize,
8971         .size           = raid5_size,
8972         .check_reshape  = raid6_check_reshape,
8973         .start_reshape  = raid5_start_reshape,
8974         .finish_reshape = raid5_finish_reshape,
8975         .quiesce        = raid5_quiesce,
8976         .takeover       = raid6_takeover,
8977         .change_consistency_policy = raid5_change_consistency_policy,
8978         .prepare_suspend = raid5_prepare_suspend,
8979 };
8980 static struct md_personality raid5_personality =
8981 {
8982         .name           = "raid5",
8983         .level          = 5,
8984         .owner          = THIS_MODULE,
8985         .make_request   = raid5_make_request,
8986         .run            = raid5_run,
8987         .start          = raid5_start,
8988         .free           = raid5_free,
8989         .status         = raid5_status,
8990         .error_handler  = raid5_error,
8991         .hot_add_disk   = raid5_add_disk,
8992         .hot_remove_disk= raid5_remove_disk,
8993         .spare_active   = raid5_spare_active,
8994         .sync_request   = raid5_sync_request,
8995         .resize         = raid5_resize,
8996         .size           = raid5_size,
8997         .check_reshape  = raid5_check_reshape,
8998         .start_reshape  = raid5_start_reshape,
8999         .finish_reshape = raid5_finish_reshape,
9000         .quiesce        = raid5_quiesce,
9001         .takeover       = raid5_takeover,
9002         .change_consistency_policy = raid5_change_consistency_policy,
9003         .prepare_suspend = raid5_prepare_suspend,
9004 };
9005
9006 static struct md_personality raid4_personality =
9007 {
9008         .name           = "raid4",
9009         .level          = 4,
9010         .owner          = THIS_MODULE,
9011         .make_request   = raid5_make_request,
9012         .run            = raid5_run,
9013         .start          = raid5_start,
9014         .free           = raid5_free,
9015         .status         = raid5_status,
9016         .error_handler  = raid5_error,
9017         .hot_add_disk   = raid5_add_disk,
9018         .hot_remove_disk= raid5_remove_disk,
9019         .spare_active   = raid5_spare_active,
9020         .sync_request   = raid5_sync_request,
9021         .resize         = raid5_resize,
9022         .size           = raid5_size,
9023         .check_reshape  = raid5_check_reshape,
9024         .start_reshape  = raid5_start_reshape,
9025         .finish_reshape = raid5_finish_reshape,
9026         .quiesce        = raid5_quiesce,
9027         .takeover       = raid4_takeover,
9028         .change_consistency_policy = raid5_change_consistency_policy,
9029         .prepare_suspend = raid5_prepare_suspend,
9030 };
9031
9032 static int __init raid5_init(void)
9033 {
9034         int ret;
9035
9036         raid5_wq = alloc_workqueue("raid5wq",
9037                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
9038         if (!raid5_wq)
9039                 return -ENOMEM;
9040
9041         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
9042                                       "md/raid5:prepare",
9043                                       raid456_cpu_up_prepare,
9044                                       raid456_cpu_dead);
9045         if (ret) {
9046                 destroy_workqueue(raid5_wq);
9047                 return ret;
9048         }
9049         register_md_personality(&raid6_personality);
9050         register_md_personality(&raid5_personality);
9051         register_md_personality(&raid4_personality);
9052         return 0;
9053 }
9054
9055 static void raid5_exit(void)
9056 {
9057         unregister_md_personality(&raid6_personality);
9058         unregister_md_personality(&raid5_personality);
9059         unregister_md_personality(&raid4_personality);
9060         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
9061         destroy_workqueue(raid5_wq);
9062 }
9063
9064 module_init(raid5_init);
9065 module_exit(raid5_exit);
9066 MODULE_LICENSE("GPL");
9067 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
9068 MODULE_ALIAS("md-personality-4"); /* RAID5 */
9069 MODULE_ALIAS("md-raid5");
9070 MODULE_ALIAS("md-raid4");
9071 MODULE_ALIAS("md-level-5");
9072 MODULE_ALIAS("md-level-4");
9073 MODULE_ALIAS("md-personality-8"); /* RAID6 */
9074 MODULE_ALIAS("md-raid6");
9075 MODULE_ALIAS("md-level-6");
9076
9077 /* This used to be two separate modules, they were: */
9078 MODULE_ALIAS("raid5");
9079 MODULE_ALIAS("raid6");