drivers/md/raid5.c

   1 /*
   2  * raid5.c : Multiple Devices driver for Linux
   3  *         Copyright (C) 1996, 1997 Ingo Molnar, Miguel de Icaza, Gadi Oxman
   4  *         Copyright (C) 1999, 2000 Ingo Molnar
   5  *         Copyright (C) 2002, 2003 H. Peter Anvin
   6  *
   7  * RAID-4/5/6 management functions.
   8  * Thanks to Penguin Computing for making the RAID-6 development possible
   9  * by donating a test server!
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2, or (at your option)
  14  * any later version.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * (for example /usr/src/linux/COPYING); if not, write to the Free
  18  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 /*
  22  * BITMAP UNPLUGGING:
  23  *
  24  * The sequencing for updating the bitmap reliably is a little
  25  * subtle (and I got it wrong the first time) so it deserves some
  26  * explanation.
  27  *
  28  * We group bitmap updates into batches.  Each batch has a number.
  29  * We may write out several batches at once, but that isn't very important.
  30  * conf->seq_write is the number of the last batch successfully written.
  31  * conf->seq_flush is the number of the last batch that was closed to
  32  *    new additions.
  33  * When we discover that we will need to write to any block in a stripe
  34  * (in add_stripe_bio) we update the in-memory bitmap and record in sh->bm_seq
  35  * the number of the batch it will be in. This is seq_flush+1.
  36  * When we are ready to do a write, if that batch hasn't been written yet,
  37  *   we plug the array and queue the stripe for later.
  38  * When an unplug happens, we increment bm_flush, thus closing the current
  39  *   batch.
  40  * When we notice that bm_flush > bm_write, we write out all pending updates
  41  * to the bitmap, and advance bm_write to where bm_flush was.
  42  * This may occasionally write a bit out twice, but is sure never to
  43  * miss any bits.
  44  */
  45
  46 #include <linux/blkdev.h>
  47 #include <linux/kthread.h>
  48 #include <linux/raid/pq.h>
  49 #include <linux/async_tx.h>
  50 #include <linux/module.h>
  51 #include <linux/async.h>
  52 #include <linux/seq_file.h>
  53 #include <linux/cpu.h>
  54 #include <linux/slab.h>
  55 #include <linux/ratelimit.h>
  56 #include <linux/nodemask.h>
  57 #include <linux/flex_array.h>
  58
  59 #include <trace/events/block.h>
  60 #include <linux/list_sort.h>
  61
  62 #include "md.h"
  63 #include "raid5.h"
  64 #include "raid0.h"
  65 #include "md-bitmap.h"
  66 #include "raid5-log.h"
  67
  68 #define UNSUPPORTED_MDDEV_FLAGS (1L << MD_FAILFAST_SUPPORTED)
  69
  70 #define cpu_to_group(cpu) cpu_to_node(cpu)
  71 #define ANY_GROUP NUMA_NO_NODE
  72
  73 static bool devices_handle_discard_safely = false;
  74 module_param(devices_handle_discard_safely, bool, 0644);
  75 MODULE_PARM_DESC(devices_handle_discard_safely,
  76                  "Set to Y if all devices in each array reliably return zeroes on reads from discarded regions");
  77 static struct workqueue_struct *raid5_wq;
  78
  79 static inline struct hlist_head *stripe_hash(struct r5conf *conf, sector_t sect)
  80 {
  81         int hash = (sect >> STRIPE_SHIFT) & HASH_MASK;
  82         return &conf->stripe_hashtbl[hash];
  83 }
  84
  85 static inline int stripe_hash_locks_hash(sector_t sect)
  86 {
  87         return (sect >> STRIPE_SHIFT) & STRIPE_HASH_LOCKS_MASK;
  88 }
  89
  90 static inline void lock_device_hash_lock(struct r5conf *conf, int hash)
  91 {
  92         spin_lock_irq(conf->hash_locks + hash);
  93         spin_lock(&conf->device_lock);
  94 }
  95
  96 static inline void unlock_device_hash_lock(struct r5conf *conf, int hash)
  97 {
  98         spin_unlock(&conf->device_lock);
  99         spin_unlock_irq(conf->hash_locks + hash);
 100 }
 101
 102 static inline void lock_all_device_hash_locks_irq(struct r5conf *conf)
 103 {
 104         int i;
 105         spin_lock_irq(conf->hash_locks);
 106         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
 107                 spin_lock_nest_lock(conf->hash_locks + i, conf->hash_locks);
 108         spin_lock(&conf->device_lock);
 109 }
 110
 111 static inline void unlock_all_device_hash_locks_irq(struct r5conf *conf)
 112 {
 113         int i;
 114         spin_unlock(&conf->device_lock);
 115         for (i = NR_STRIPE_HASH_LOCKS - 1; i; i--)
 116                 spin_unlock(conf->hash_locks + i);
 117         spin_unlock_irq(conf->hash_locks);
 118 }
 119
 120 /* Find first data disk in a raid6 stripe */
 121 static inline int raid6_d0(struct stripe_head *sh)
 122 {
 123         if (sh->ddf_layout)
 124                 /* ddf always start from first device */
 125                 return 0;
 126         /* md starts just after Q block */
 127         if (sh->qd_idx == sh->disks - 1)
 128                 return 0;
 129         else
 130                 return sh->qd_idx + 1;
 131 }
 132 static inline int raid6_next_disk(int disk, int raid_disks)
 133 {
 134         disk++;
 135         return (disk < raid_disks) ? disk : 0;
 136 }
 137
 138 /* When walking through the disks in a raid5, starting at raid6_d0,
 139  * We need to map each disk to a 'slot', where the data disks are slot
 140  * 0 .. raid_disks-3, the parity disk is raid_disks-2 and the Q disk
 141  * is raid_disks-1.  This help does that mapping.
 142  */
 143 static int raid6_idx_to_slot(int idx, struct stripe_head *sh,
 144                              int *count, int syndrome_disks)
 145 {
 146         int slot = *count;
 147
 148         if (sh->ddf_layout)
 149                 (*count)++;
 150         if (idx == sh->pd_idx)
 151                 return syndrome_disks;
 152         if (idx == sh->qd_idx)
 153                 return syndrome_disks + 1;
 154         if (!sh->ddf_layout)
 155                 (*count)++;
 156         return slot;
 157 }
 158
 159 static void print_raid5_conf (struct r5conf *conf);
 160
 161 static int stripe_operations_active(struct stripe_head *sh)
 162 {
 163         return sh->check_state || sh->reconstruct_state ||
 164                test_bit(STRIPE_BIOFILL_RUN, &sh->state) ||
 165                test_bit(STRIPE_COMPUTE_RUN, &sh->state);
 166 }
 167
 168 static bool stripe_is_lowprio(struct stripe_head *sh)
 169 {
 170         return (test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) ||
 171                 test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state)) &&
 172                !test_bit(STRIPE_R5C_CACHING, &sh->state);
 173 }
 174
 175 static void raid5_wakeup_stripe_thread(struct stripe_head *sh)
 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 {
 224         int i;
 225         int injournal = 0;      /* number of date pages with R5_InJournal */
 226
 227         BUG_ON(!list_empty(&sh->lru));
 228         BUG_ON(atomic_read(&conf->active_stripes)==0);
 229
 230         if (r5c_is_writeback(conf->log))
 231                 for (i = sh->disks; i--; )
 232                         if (test_bit(R5_InJournal, &sh->dev[i].flags))
 233                                 injournal++;
 234         /*
 235          * In the following cases, the stripe cannot be released to cached
 236          * lists. Therefore, we make the stripe write out and set
 237          * STRIPE_HANDLE:
 238          *   1. when quiesce in r5c write back;
 239          *   2. when resync is requested fot the stripe.
 240          */
 241         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) ||
 242             (conf->quiesce && r5c_is_writeback(conf->log) &&
 243              !test_bit(STRIPE_HANDLE, &sh->state) && injournal != 0)) {
 244                 if (test_bit(STRIPE_R5C_CACHING, &sh->state))
 245                         r5c_make_stripe_write_out(sh);
 246                 set_bit(STRIPE_HANDLE, &sh->state);
 247         }
 248
 249         if (test_bit(STRIPE_HANDLE, &sh->state)) {
 250                 if (test_bit(STRIPE_DELAYED, &sh->state) &&
 251                     !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 252                         list_add_tail(&sh->lru, &conf->delayed_list);
 253                 else if (test_bit(STRIPE_BIT_DELAY, &sh->state) &&
 254                            sh->bm_seq - conf->seq_write > 0)
 255                         list_add_tail(&sh->lru, &conf->bitmap_list);
 256                 else {
 257                         clear_bit(STRIPE_DELAYED, &sh->state);
 258                         clear_bit(STRIPE_BIT_DELAY, &sh->state);
 259                         if (conf->worker_cnt_per_group == 0) {
 260                                 if (stripe_is_lowprio(sh))
 261                                         list_add_tail(&sh->lru,
 262                                                         &conf->loprio_list);
 263                                 else
 264                                         list_add_tail(&sh->lru,
 265                                                         &conf->handle_list);
 266                         } else {
 267                                 raid5_wakeup_stripe_thread(sh);
 268                                 return;
 269                         }
 270                 }
 271                 md_wakeup_thread(conf->mddev->thread);
 272         } else {
 273                 BUG_ON(stripe_operations_active(sh));
 274                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 275                         if (atomic_dec_return(&conf->preread_active_stripes)
 276                             < IO_THRESHOLD)
 277                                 md_wakeup_thread(conf->mddev->thread);
 278                 atomic_dec(&conf->active_stripes);
 279                 if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 280                         if (!r5c_is_writeback(conf->log))
 281                                 list_add_tail(&sh->lru, temp_inactive_list);
 282                         else {
 283                                 WARN_ON(test_bit(R5_InJournal, &sh->dev[sh->pd_idx].flags));
 284                                 if (injournal == 0)
 285                                         list_add_tail(&sh->lru, temp_inactive_list);
 286                                 else if (injournal == conf->raid_disks - conf->max_degraded) {
 287                                         /* full stripe */
 288                                         if (!test_and_set_bit(STRIPE_R5C_FULL_STRIPE, &sh->state))
 289                                                 atomic_inc(&conf->r5c_cached_full_stripes);
 290                                         if (test_and_clear_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state))
 291                                                 atomic_dec(&conf->r5c_cached_partial_stripes);
 292                                         list_add_tail(&sh->lru, &conf->r5c_full_stripe_list);
 293                                         r5c_check_cached_full_stripe(conf);
 294                                 } else
 295                                         /*
 296                                          * STRIPE_R5C_PARTIAL_STRIPE is set in
 297                                          * r5c_try_caching_write(). No need to
 298                                          * set it again.
 299                                          */
 300                                         list_add_tail(&sh->lru, &conf->r5c_partial_stripe_list);
 301                         }
 302                 }
 303         }
 304 }
 305
 306 static void __release_stripe(struct r5conf *conf, struct stripe_head *sh,
 307                              struct list_head *temp_inactive_list)
 308 {
 309         if (atomic_dec_and_test(&sh->count))
 310                 do_release_stripe(conf, sh, temp_inactive_list);
 311 }
 312
 313 /*
 314  * @hash could be NR_STRIPE_HASH_LOCKS, then we have a list of inactive_list
 315  *
 316  * Be careful: Only one task can add/delete stripes from temp_inactive_list at
 317  * given time. Adding stripes only takes device lock, while deleting stripes
 318  * only takes hash lock.
 319  */
 320 static void release_inactive_stripe_list(struct r5conf *conf,
 321                                          struct list_head *temp_inactive_list,
 322                                          int hash)
 323 {
 324         int size;
 325         bool do_wakeup = false;
 326         unsigned long flags;
 327
 328         if (hash == NR_STRIPE_HASH_LOCKS) {
 329                 size = NR_STRIPE_HASH_LOCKS;
 330                 hash = NR_STRIPE_HASH_LOCKS - 1;
 331         } else
 332                 size = 1;
 333         while (size) {
 334                 struct list_head *list = &temp_inactive_list[size - 1];
 335
 336                 /*
 337                  * We don't hold any lock here yet, raid5_get_active_stripe() might
 338                  * remove stripes from the list
 339                  */
 340                 if (!list_empty_careful(list)) {
 341                         spin_lock_irqsave(conf->hash_locks + hash, flags);
 342                         if (list_empty(conf->inactive_list + hash) &&
 343                             !list_empty(list))
 344                                 atomic_dec(&conf->empty_inactive_list_nr);
 345                         list_splice_tail_init(list, conf->inactive_list + hash);
 346                         do_wakeup = true;
 347                         spin_unlock_irqrestore(conf->hash_locks + hash, flags);
 348                 }
 349                 size--;
 350                 hash--;
 351         }
 352
 353         if (do_wakeup) {
 354                 wake_up(&conf->wait_for_stripe);
 355                 if (atomic_read(&conf->active_stripes) == 0)
 356                         wake_up(&conf->wait_for_quiescent);
 357                 if (conf->retry_read_aligned)
 358                         md_wakeup_thread(conf->mddev->thread);
 359         }
 360 }
 361
 362 /* should hold conf->device_lock already */
 363 static int release_stripe_list(struct r5conf *conf,
 364                                struct list_head *temp_inactive_list)
 365 {
 366         struct stripe_head *sh, *t;
 367         int count = 0;
 368         struct llist_node *head;
 369
 370         head = llist_del_all(&conf->released_stripes);
 371         head = llist_reverse_order(head);
 372         llist_for_each_entry_safe(sh, t, head, release_list) {
 373                 int hash;
 374
 375                 /* sh could be readded after STRIPE_ON_RELEASE_LIST is cleard */
 376                 smp_mb();
 377                 clear_bit(STRIPE_ON_RELEASE_LIST, &sh->state);
 378                 /*
 379                  * Don't worry the bit is set here, because if the bit is set
 380                  * again, the count is always > 1. This is true for
 381                  * STRIPE_ON_UNPLUG_LIST bit too.
 382                  */
 383                 hash = sh->hash_lock_index;
 384                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
 385                 count++;
 386         }
 387
 388         return count;
 389 }
 390
 391 void raid5_release_stripe(struct stripe_head *sh)
 392 {
 393         struct r5conf *conf = sh->raid_conf;
 394         unsigned long flags;
 395         struct list_head list;
 396         int hash;
 397         bool wakeup;
 398
 399         /* Avoid release_list until the last reference.
 400          */
 401         if (atomic_add_unless(&sh->count, -1, 1))
 402                 return;
 403
 404         if (unlikely(!conf->mddev->thread) ||
 405                 test_and_set_bit(STRIPE_ON_RELEASE_LIST, &sh->state))
 406                 goto slow_path;
 407         wakeup = llist_add(&sh->release_list, &conf->released_stripes);
 408         if (wakeup)
 409                 md_wakeup_thread(conf->mddev->thread);
 410         return;
 411 slow_path:
 412         local_irq_save(flags);
 413         /* we are ok here if STRIPE_ON_RELEASE_LIST is set or not */
 414         if (atomic_dec_and_lock(&sh->count, &conf->device_lock)) {
 415                 INIT_LIST_HEAD(&list);
 416                 hash = sh->hash_lock_index;
 417                 do_release_stripe(conf, sh, &list);
 418                 spin_unlock(&conf->device_lock);
 419                 release_inactive_stripe_list(conf, &list, hash);
 420         }
 421         local_irq_restore(flags);
 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 static void shrink_buffers(struct stripe_head *sh)
 463 {
 464         struct page *p;
 465         int i;
 466         int num = sh->raid_conf->pool_size;
 467
 468         for (i = 0; i < num ; i++) {
 469                 WARN_ON(sh->dev[i].page != sh->dev[i].orig_page);
 470                 p = sh->dev[i].page;
 471                 if (!p)
 472                         continue;
 473                 sh->dev[i].page = NULL;
 474                 put_page(p);
 475         }
 476 }
 477
 478 static int grow_buffers(struct stripe_head *sh, gfp_t gfp)
 479 {
 480         int i;
 481         int num = sh->raid_conf->pool_size;
 482
 483         for (i = 0; i < num; i++) {
 484                 struct page *page;
 485
 486                 if (!(page = alloc_page(gfp))) {
 487                         return 1;
 488                 }
 489                 sh->dev[i].page = page;
 490                 sh->dev[i].orig_page = page;
 491         }
 492
 493         return 0;
 494 }
 495
 496 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
 497                             struct stripe_head *sh);
 498
 499 static void init_stripe(struct stripe_head *sh, sector_t sector, int previous)
 500 {
 501         struct r5conf *conf = sh->raid_conf;
 502         int i, seq;
 503
 504         BUG_ON(atomic_read(&sh->count) != 0);
 505         BUG_ON(test_bit(STRIPE_HANDLE, &sh->state));
 506         BUG_ON(stripe_operations_active(sh));
 507         BUG_ON(sh->batch_head);
 508
 509         pr_debug("init_stripe called, stripe %llu\n",
 510                 (unsigned long long)sector);
 511 retry:
 512         seq = read_seqcount_begin(&conf->gen_lock);
 513         sh->generation = conf->generation - previous;
 514         sh->disks = previous ? conf->previous_raid_disks : conf->raid_disks;
 515         sh->sector = sector;
 516         stripe_set_idx(sector, conf, previous, sh);
 517         sh->state = 0;
 518
 519         for (i = sh->disks; i--; ) {
 520                 struct r5dev *dev = &sh->dev[i];
 521
 522                 if (dev->toread || dev->read || dev->towrite || dev->written ||
 523                     test_bit(R5_LOCKED, &dev->flags)) {
 524                         pr_err("sector=%llx i=%d %p %p %p %p %d\n",
 525                                (unsigned long long)sh->sector, i, dev->toread,
 526                                dev->read, dev->towrite, dev->written,
 527                                test_bit(R5_LOCKED, &dev->flags));
 528                         WARN_ON(1);
 529                 }
 530                 dev->flags = 0;
 531                 dev->sector = raid5_compute_blocknr(sh, i, previous);
 532         }
 533         if (read_seqcount_retry(&conf->gen_lock, seq))
 534                 goto retry;
 535         sh->overwrite_disks = 0;
 536         insert_hash(conf, sh);
 537         sh->cpu = smp_processor_id();
 538         set_bit(STRIPE_BATCH_READY, &sh->state);
 539 }
 540
 541 static struct stripe_head *__find_stripe(struct r5conf *conf, sector_t sector,
 542                                          short generation)
 543 {
 544         struct stripe_head *sh;
 545
 546         pr_debug("__find_stripe, sector %llu\n", (unsigned long long)sector);
 547         hlist_for_each_entry(sh, stripe_hash(conf, sector), hash)
 548                 if (sh->sector == sector && sh->generation == generation)
 549                         return sh;
 550         pr_debug("__stripe %llu not in cache\n", (unsigned long long)sector);
 551         return NULL;
 552 }
 553
 554 /*
 555  * Need to check if array has failed when deciding whether to:
 556  *  - start an array
 557  *  - remove non-faulty devices
 558  *  - add a spare
 559  *  - allow a reshape
 560  * This determination is simple when no reshape is happening.
 561  * However if there is a reshape, we need to carefully check
 562  * both the before and after sections.
 563  * This is because some failed devices may only affect one
 564  * of the two sections, and some non-in_sync devices may
 565  * be insync in the section most affected by failed devices.
 566  */
 567 int raid5_calc_degraded(struct r5conf *conf)
 568 {
 569         int degraded, degraded2;
 570         int i;
 571
 572         rcu_read_lock();
 573         degraded = 0;
 574         for (i = 0; i < conf->previous_raid_disks; i++) {
 575                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 576                 if (rdev && test_bit(Faulty, &rdev->flags))
 577                         rdev = rcu_dereference(conf->disks[i].replacement);
 578                 if (!rdev || test_bit(Faulty, &rdev->flags))
 579                         degraded++;
 580                 else if (test_bit(In_sync, &rdev->flags))
 581                         ;
 582                 else
 583                         /* not in-sync or faulty.
 584                          * If the reshape increases the number of devices,
 585                          * this is being recovered by the reshape, so
 586                          * this 'previous' section is not in_sync.
 587                          * If the number of devices is being reduced however,
 588                          * the device can only be part of the array if
 589                          * we are reverting a reshape, so this section will
 590                          * be in-sync.
 591                          */
 592                         if (conf->raid_disks >= conf->previous_raid_disks)
 593                                 degraded++;
 594         }
 595         rcu_read_unlock();
 596         if (conf->raid_disks == conf->previous_raid_disks)
 597                 return degraded;
 598         rcu_read_lock();
 599         degraded2 = 0;
 600         for (i = 0; i < conf->raid_disks; i++) {
 601                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
 602                 if (rdev && test_bit(Faulty, &rdev->flags))
 603                         rdev = rcu_dereference(conf->disks[i].replacement);
 604                 if (!rdev || test_bit(Faulty, &rdev->flags))
 605                         degraded2++;
 606                 else if (test_bit(In_sync, &rdev->flags))
 607                         ;
 608                 else
 609                         /* not in-sync or faulty.
 610                          * If reshape increases the number of devices, this
 611                          * section has already been recovered, else it
 612                          * almost certainly hasn't.
 613                          */
 614                         if (conf->raid_disks <= conf->previous_raid_disks)
 615                                 degraded2++;
 616         }
 617         rcu_read_unlock();
 618         if (degraded2 > degraded)
 619                 return degraded2;
 620         return degraded;
 621 }
 622
 623 static int has_failed(struct r5conf *conf)
 624 {
 625         int degraded;
 626
 627         if (conf->mddev->reshape_position == MaxSector)
 628                 return conf->mddev->degraded > conf->max_degraded;
 629
 630         degraded = raid5_calc_degraded(conf);
 631         if (degraded > conf->max_degraded)
 632                 return 1;
 633         return 0;
 634 }
 635
 636 struct stripe_head *
 637 raid5_get_active_stripe(struct r5conf *conf, sector_t sector,
 638                         int previous, int noblock, int noquiesce)
 639 {
 640         struct stripe_head *sh;
 641         int hash = stripe_hash_locks_hash(sector);
 642         int inc_empty_inactive_list_flag;
 643
 644         pr_debug("get_stripe, sector %llu\n", (unsigned long long)sector);
 645
 646         spin_lock_irq(conf->hash_locks + hash);
 647
 648         do {
 649                 wait_event_lock_irq(conf->wait_for_quiescent,
 650                                     conf->quiesce == 0 || noquiesce,
 651                                     *(conf->hash_locks + hash));
 652                 sh = __find_stripe(conf, sector, conf->generation - previous);
 653                 if (!sh) {
 654                         if (!test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state)) {
 655                                 sh = get_free_stripe(conf, hash);
 656                                 if (!sh && !test_bit(R5_DID_ALLOC,
 657                                                      &conf->cache_state))
 658                                         set_bit(R5_ALLOC_MORE,
 659                                                 &conf->cache_state);
 660                         }
 661                         if (noblock && sh == NULL)
 662                                 break;
 663
 664                         r5c_check_stripe_cache_usage(conf);
 665                         if (!sh) {
 666                                 set_bit(R5_INACTIVE_BLOCKED,
 667                                         &conf->cache_state);
 668                                 r5l_wake_reclaim(conf->log, 0);
 669                                 wait_event_lock_irq(
 670                                         conf->wait_for_stripe,
 671                                         !list_empty(conf->inactive_list + hash) &&
 672                                         (atomic_read(&conf->active_stripes)
 673                                          < (conf->max_nr_stripes * 3 / 4)
 674                                          || !test_bit(R5_INACTIVE_BLOCKED,
 675                                                       &conf->cache_state)),
 676                                         *(conf->hash_locks + hash));
 677                                 clear_bit(R5_INACTIVE_BLOCKED,
 678                                           &conf->cache_state);
 679                         } else {
 680                                 init_stripe(sh, sector, previous);
 681                                 atomic_inc(&sh->count);
 682                         }
 683                 } else if (!atomic_inc_not_zero(&sh->count)) {
 684                         spin_lock(&conf->device_lock);
 685                         if (!atomic_read(&sh->count)) {
 686                                 if (!test_bit(STRIPE_HANDLE, &sh->state))
 687                                         atomic_inc(&conf->active_stripes);
 688                                 BUG_ON(list_empty(&sh->lru) &&
 689                                        !test_bit(STRIPE_EXPANDING, &sh->state));
 690                                 inc_empty_inactive_list_flag = 0;
 691                                 if (!list_empty(conf->inactive_list + hash))
 692                                         inc_empty_inactive_list_flag = 1;
 693                                 list_del_init(&sh->lru);
 694                                 if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 695                                         atomic_inc(&conf->empty_inactive_list_nr);
 696                                 if (sh->group) {
 697                                         sh->group->stripes_cnt--;
 698                                         sh->group = NULL;
 699                                 }
 700                         }
 701                         atomic_inc(&sh->count);
 702                         spin_unlock(&conf->device_lock);
 703                 }
 704         } while (sh == NULL);
 705
 706         spin_unlock_irq(conf->hash_locks + hash);
 707         return sh;
 708 }
 709
 710 static bool is_full_stripe_write(struct stripe_head *sh)
 711 {
 712         BUG_ON(sh->overwrite_disks > (sh->disks - sh->raid_conf->max_degraded));
 713         return sh->overwrite_disks == (sh->disks - sh->raid_conf->max_degraded);
 714 }
 715
 716 static void lock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 717 {
 718         if (sh1 > sh2) {
 719                 spin_lock_irq(&sh2->stripe_lock);
 720                 spin_lock_nested(&sh1->stripe_lock, 1);
 721         } else {
 722                 spin_lock_irq(&sh1->stripe_lock);
 723                 spin_lock_nested(&sh2->stripe_lock, 1);
 724         }
 725 }
 726
 727 static void unlock_two_stripes(struct stripe_head *sh1, struct stripe_head *sh2)
 728 {
 729         spin_unlock(&sh1->stripe_lock);
 730         spin_unlock_irq(&sh2->stripe_lock);
 731 }
 732
 733 /* Only freshly new full stripe normal write stripe can be added to a batch list */
 734 static bool stripe_can_batch(struct stripe_head *sh)
 735 {
 736         struct r5conf *conf = sh->raid_conf;
 737
 738         if (conf->log || raid5_has_ppl(conf))
 739                 return false;
 740         return test_bit(STRIPE_BATCH_READY, &sh->state) &&
 741                 !test_bit(STRIPE_BITMAP_PENDING, &sh->state) &&
 742                 is_full_stripe_write(sh);
 743 }
 744
 745 /* we only do back search */
 746 static void stripe_add_to_batch_list(struct r5conf *conf, struct stripe_head *sh)
 747 {
 748         struct stripe_head *head;
 749         sector_t head_sector, tmp_sec;
 750         int hash;
 751         int dd_idx;
 752         int inc_empty_inactive_list_flag;
 753
 754         /* Don't cross chunks, so stripe pd_idx/qd_idx is the same */
 755         tmp_sec = sh->sector;
 756         if (!sector_div(tmp_sec, conf->chunk_sectors))
 757                 return;
 758         head_sector = sh->sector - STRIPE_SECTORS;
 759
 760         hash = stripe_hash_locks_hash(head_sector);
 761         spin_lock_irq(conf->hash_locks + hash);
 762         head = __find_stripe(conf, head_sector, conf->generation);
 763         if (head && !atomic_inc_not_zero(&head->count)) {
 764                 spin_lock(&conf->device_lock);
 765                 if (!atomic_read(&head->count)) {
 766                         if (!test_bit(STRIPE_HANDLE, &head->state))
 767                                 atomic_inc(&conf->active_stripes);
 768                         BUG_ON(list_empty(&head->lru) &&
 769                                !test_bit(STRIPE_EXPANDING, &head->state));
 770                         inc_empty_inactive_list_flag = 0;
 771                         if (!list_empty(conf->inactive_list + hash))
 772                                 inc_empty_inactive_list_flag = 1;
 773                         list_del_init(&head->lru);
 774                         if (list_empty(conf->inactive_list + hash) && inc_empty_inactive_list_flag)
 775                                 atomic_inc(&conf->empty_inactive_list_nr);
 776                         if (head->group) {
 777                                 head->group->stripes_cnt--;
 778                                 head->group = NULL;
 779                         }
 780                 }
 781                 atomic_inc(&head->count);
 782                 spin_unlock(&conf->device_lock);
 783         }
 784         spin_unlock_irq(conf->hash_locks + hash);
 785
 786         if (!head)
 787                 return;
 788         if (!stripe_can_batch(head))
 789                 goto out;
 790
 791         lock_two_stripes(head, sh);
 792         /* clear_batch_ready clear the flag */
 793         if (!stripe_can_batch(head) || !stripe_can_batch(sh))
 794                 goto unlock_out;
 795
 796         if (sh->batch_head)
 797                 goto unlock_out;
 798
 799         dd_idx = 0;
 800         while (dd_idx == sh->pd_idx || dd_idx == sh->qd_idx)
 801                 dd_idx++;
 802         if (head->dev[dd_idx].towrite->bi_opf != sh->dev[dd_idx].towrite->bi_opf ||
 803             bio_op(head->dev[dd_idx].towrite) != bio_op(sh->dev[dd_idx].towrite))
 804                 goto unlock_out;
 805
 806         if (head->batch_head) {
 807                 spin_lock(&head->batch_head->batch_lock);
 808                 /* This batch list is already running */
 809                 if (!stripe_can_batch(head)) {
 810                         spin_unlock(&head->batch_head->batch_lock);
 811                         goto unlock_out;
 812                 }
 813                 /*
 814                  * We must assign batch_head of this stripe within the
 815                  * batch_lock, otherwise clear_batch_ready of batch head
 816                  * stripe could clear BATCH_READY bit of this stripe and
 817                  * this stripe->batch_head doesn't get assigned, which
 818                  * could confuse clear_batch_ready for this stripe
 819                  */
 820                 sh->batch_head = head->batch_head;
 821
 822                 /*
 823                  * at this point, head's BATCH_READY could be cleared, but we
 824                  * can still add the stripe to batch list
 825                  */
 826                 list_add(&sh->batch_list, &head->batch_list);
 827                 spin_unlock(&head->batch_head->batch_lock);
 828         } else {
 829                 head->batch_head = head;
 830                 sh->batch_head = head->batch_head;
 831                 spin_lock(&head->batch_lock);
 832                 list_add_tail(&sh->batch_list, &head->batch_list);
 833                 spin_unlock(&head->batch_lock);
 834         }
 835
 836         if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 837                 if (atomic_dec_return(&conf->preread_active_stripes)
 838                     < IO_THRESHOLD)
 839                         md_wakeup_thread(conf->mddev->thread);
 840
 841         if (test_and_clear_bit(STRIPE_BIT_DELAY, &sh->state)) {
 842                 int seq = sh->bm_seq;
 843                 if (test_bit(STRIPE_BIT_DELAY, &sh->batch_head->state) &&
 844                     sh->batch_head->bm_seq > seq)
 845                         seq = sh->batch_head->bm_seq;
 846                 set_bit(STRIPE_BIT_DELAY, &sh->batch_head->state);
 847                 sh->batch_head->bm_seq = seq;
 848         }
 849
 850         atomic_inc(&sh->count);
 851 unlock_out:
 852         unlock_two_stripes(head, sh);
 853 out:
 854         raid5_release_stripe(head);
 855 }
 856
 857 /* Determine if 'data_offset' or 'new_data_offset' should be used
 858  * in this stripe_head.
 859  */
 860 static int use_new_offset(struct r5conf *conf, struct stripe_head *sh)
 861 {
 862         sector_t progress = conf->reshape_progress;
 863         /* Need a memory barrier to make sure we see the value
 864          * of conf->generation, or ->data_offset that was set before
 865          * reshape_progress was updated.
 866          */
 867         smp_rmb();
 868         if (progress == MaxSector)
 869                 return 0;
 870         if (sh->generation == conf->generation - 1)
 871                 return 0;
 872         /* We are in a reshape, and this is a new-generation stripe,
 873          * so use new_data_offset.
 874          */
 875         return 1;
 876 }
 877
 878 static void dispatch_bio_list(struct bio_list *tmp)
 879 {
 880         struct bio *bio;
 881
 882         while ((bio = bio_list_pop(tmp)))
 883                 generic_make_request(bio);
 884 }
 885
 886 static int cmp_stripe(void *priv, struct list_head *a, struct list_head *b)
 887 {
 888         const struct r5pending_data *da = list_entry(a,
 889                                 struct r5pending_data, sibling);
 890         const struct r5pending_data *db = list_entry(b,
 891                                 struct r5pending_data, sibling);
 892         if (da->sector > db->sector)
 893                 return 1;
 894         if (da->sector < db->sector)
 895                 return -1;
 896         return 0;
 897 }
 898
 899 static void dispatch_defer_bios(struct r5conf *conf, int target,
 900                                 struct bio_list *list)
 901 {
 902         struct r5pending_data *data;
 903         struct list_head *first, *next = NULL;
 904         int cnt = 0;
 905
 906         if (conf->pending_data_cnt == 0)
 907                 return;
 908
 909         list_sort(NULL, &conf->pending_list, cmp_stripe);
 910
 911         first = conf->pending_list.next;
 912
 913         /* temporarily move the head */
 914         if (conf->next_pending_data)
 915                 list_move_tail(&conf->pending_list,
 916                                 &conf->next_pending_data->sibling);
 917
 918         while (!list_empty(&conf->pending_list)) {
 919                 data = list_first_entry(&conf->pending_list,
 920                         struct r5pending_data, sibling);
 921                 if (&data->sibling == first)
 922                         first = data->sibling.next;
 923                 next = data->sibling.next;
 924
 925                 bio_list_merge(list, &data->bios);
 926                 list_move(&data->sibling, &conf->free_list);
 927                 cnt++;
 928                 if (cnt >= target)
 929                         break;
 930         }
 931         conf->pending_data_cnt -= cnt;
 932         BUG_ON(conf->pending_data_cnt < 0 || cnt < target);
 933
 934         if (next != &conf->pending_list)
 935                 conf->next_pending_data = list_entry(next,
 936                                 struct r5pending_data, sibling);
 937         else
 938                 conf->next_pending_data = NULL;
 939         /* list isn't empty */
 940         if (first != &conf->pending_list)
 941                 list_move_tail(&conf->pending_list, first);
 942 }
 943
 944 static void flush_deferred_bios(struct r5conf *conf)
 945 {
 946         struct bio_list tmp = BIO_EMPTY_LIST;
 947
 948         if (conf->pending_data_cnt == 0)
 949                 return;
 950
 951         spin_lock(&conf->pending_bios_lock);
 952         dispatch_defer_bios(conf, conf->pending_data_cnt, &tmp);
 953         BUG_ON(conf->pending_data_cnt != 0);
 954         spin_unlock(&conf->pending_bios_lock);
 955
 956         dispatch_bio_list(&tmp);
 957 }
 958
 959 static void defer_issue_bios(struct r5conf *conf, sector_t sector,
 960                                 struct bio_list *bios)
 961 {
 962         struct bio_list tmp = BIO_EMPTY_LIST;
 963         struct r5pending_data *ent;
 964
 965         spin_lock(&conf->pending_bios_lock);
 966         ent = list_first_entry(&conf->free_list, struct r5pending_data,
 967                                                         sibling);
 968         list_move_tail(&ent->sibling, &conf->pending_list);
 969         ent->sector = sector;
 970         bio_list_init(&ent->bios);
 971         bio_list_merge(&ent->bios, bios);
 972         conf->pending_data_cnt++;
 973         if (conf->pending_data_cnt >= PENDING_IO_MAX)
 974                 dispatch_defer_bios(conf, PENDING_IO_ONE_FLUSH, &tmp);
 975
 976         spin_unlock(&conf->pending_bios_lock);
 977
 978         dispatch_bio_list(&tmp);
 979 }
 980
 981 static void
 982 raid5_end_read_request(struct bio *bi);
 983 static void
 984 raid5_end_write_request(struct bio *bi);
 985
 986 static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 987 {
 988         struct r5conf *conf = sh->raid_conf;
 989         int i, disks = sh->disks;
 990         struct stripe_head *head_sh = sh;
 991         struct bio_list pending_bios = BIO_EMPTY_LIST;
 992         bool should_defer;
 993
 994         might_sleep();
 995
 996         if (log_stripe(sh, s) == 0)
 997                 return;
 998
 999         should_defer = conf->batch_bio_dispatch && conf->group_cnt;
1000
1001         for (i = disks; i--; ) {
1002                 int op, op_flags = 0;
1003                 int replace_only = 0;
1004                 struct bio *bi, *rbi;
1005                 struct md_rdev *rdev, *rrdev = NULL;
1006
1007                 sh = head_sh;
1008                 if (test_and_clear_bit(R5_Wantwrite, &sh->dev[i].flags)) {
1009                         op = REQ_OP_WRITE;
1010                         if (test_and_clear_bit(R5_WantFUA, &sh->dev[i].flags))
1011                                 op_flags = REQ_FUA;
1012                         if (test_bit(R5_Discard, &sh->dev[i].flags))
1013                                 op = REQ_OP_DISCARD;
1014                 } else if (test_and_clear_bit(R5_Wantread, &sh->dev[i].flags))
1015                         op = REQ_OP_READ;
1016                 else if (test_and_clear_bit(R5_WantReplace,
1017                                             &sh->dev[i].flags)) {
1018                         op = REQ_OP_WRITE;
1019                         replace_only = 1;
1020                 } else
1021                         continue;
1022                 if (test_and_clear_bit(R5_SyncIO, &sh->dev[i].flags))
1023                         op_flags |= REQ_SYNC;
1024
1025 again:
1026                 bi = &sh->dev[i].req;
1027                 rbi = &sh->dev[i].rreq; /* For writing to replacement */
1028
1029                 rcu_read_lock();
1030                 rrdev = rcu_dereference(conf->disks[i].replacement);
1031                 smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */
1032                 rdev = rcu_dereference(conf->disks[i].rdev);
1033                 if (!rdev) {
1034                         rdev = rrdev;
1035                         rrdev = NULL;
1036                 }
1037                 if (op_is_write(op)) {
1038                         if (replace_only)
1039                                 rdev = NULL;
1040                         if (rdev == rrdev)
1041                                 /* We raced and saw duplicates */
1042                                 rrdev = NULL;
1043                 } else {
1044                         if (test_bit(R5_ReadRepl, &head_sh->dev[i].flags) && rrdev)
1045                                 rdev = rrdev;
1046                         rrdev = NULL;
1047                 }
1048
1049                 if (rdev && test_bit(Faulty, &rdev->flags))
1050                         rdev = NULL;
1051                 if (rdev)
1052                         atomic_inc(&rdev->nr_pending);
1053                 if (rrdev && test_bit(Faulty, &rrdev->flags))
1054                         rrdev = NULL;
1055                 if (rrdev)
1056                         atomic_inc(&rrdev->nr_pending);
1057                 rcu_read_unlock();
1058
1059                 /* We have already checked bad blocks for reads.  Now
1060                  * need to check for writes.  We never accept write errors
1061                  * on the replacement, so we don't to check rrdev.
1062                  */
1063                 while (op_is_write(op) && rdev &&
1064                        test_bit(WriteErrorSeen, &rdev->flags)) {
1065                         sector_t first_bad;
1066                         int bad_sectors;
1067                         int bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
1068                                               &first_bad, &bad_sectors);
1069                         if (!bad)
1070                                 break;
1071
1072                         if (bad < 0) {
1073                                 set_bit(BlockedBadBlocks, &rdev->flags);
1074                                 if (!conf->mddev->external &&
1075                                     conf->mddev->sb_flags) {
1076                                         /* It is very unlikely, but we might
1077                                          * still need to write out the
1078                                          * bad block log - better give it
1079                                          * a chance*/
1080                                         md_check_recovery(conf->mddev);
1081                                 }
1082                                 /*
1083                                  * Because md_wait_for_blocked_rdev
1084                                  * will dec nr_pending, we must
1085                                  * increment it first.
1086                                  */
1087                                 atomic_inc(&rdev->nr_pending);
1088                                 md_wait_for_blocked_rdev(rdev, conf->mddev);
1089                         } else {
1090                                 /* Acknowledged bad block - skip the write */
1091                                 rdev_dec_pending(rdev, conf->mddev);
1092                                 rdev = NULL;
1093                         }
1094                 }
1095
1096                 if (rdev) {
1097                         if (s->syncing || s->expanding || s->expanded
1098                             || s->replacing)
1099                                 md_sync_acct(rdev->bdev, STRIPE_SECTORS);
1100
1101                         set_bit(STRIPE_IO_STARTED, &sh->state);
1102
1103                         bio_set_dev(bi, rdev->bdev);
1104                         bio_set_op_attrs(bi, op, op_flags);
1105                         bi->bi_end_io = op_is_write(op)
1106                                 ? raid5_end_write_request
1107                                 : raid5_end_read_request;
1108                         bi->bi_private = sh;
1109
1110                         pr_debug("%s: for %llu schedule op %d on disc %d\n",
1111                                 __func__, (unsigned long long)sh->sector,
1112                                 bi->bi_opf, i);
1113                         atomic_inc(&sh->count);
1114                         if (sh != head_sh)
1115                                 atomic_inc(&head_sh->count);
1116                         if (use_new_offset(conf, sh))
1117                                 bi->bi_iter.bi_sector = (sh->sector
1118                                                  + rdev->new_data_offset);
1119                         else
1120                                 bi->bi_iter.bi_sector = (sh->sector
1121                                                  + rdev->data_offset);
1122                         if (test_bit(R5_ReadNoMerge, &head_sh->dev[i].flags))
1123                                 bi->bi_opf |= REQ_NOMERGE;
1124
1125                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1126                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1127
1128                         if (!op_is_write(op) &&
1129                             test_bit(R5_InJournal, &sh->dev[i].flags))
1130                                 /*
1131                                  * issuing read for a page in journal, this
1132                                  * must be preparing for prexor in rmw; read
1133                                  * the data into orig_page
1134                                  */
1135                                 sh->dev[i].vec.bv_page = sh->dev[i].orig_page;
1136                         else
1137                                 sh->dev[i].vec.bv_page = sh->dev[i].page;
1138                         bi->bi_vcnt = 1;
1139                         bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1140                         bi->bi_io_vec[0].bv_offset = 0;
1141                         bi->bi_iter.bi_size = STRIPE_SIZE;
1142                         /*
1143                          * If this is discard request, set bi_vcnt 0. We don't
1144                          * want to confuse SCSI because SCSI will replace payload
1145                          */
1146                         if (op == REQ_OP_DISCARD)
1147                                 bi->bi_vcnt = 0;
1148                         if (rrdev)
1149                                 set_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags);
1150
1151                         if (conf->mddev->gendisk)
1152                                 trace_block_bio_remap(bi->bi_disk->queue,
1153                                                       bi, disk_devt(conf->mddev->gendisk),
1154                                                       sh->dev[i].sector);
1155                         if (should_defer && op_is_write(op))
1156                                 bio_list_add(&pending_bios, bi);
1157                         else
1158                                 generic_make_request(bi);
1159                 }
1160                 if (rrdev) {
1161                         if (s->syncing || s->expanding || s->expanded
1162                             || s->replacing)
1163                                 md_sync_acct(rrdev->bdev, STRIPE_SECTORS);
1164
1165                         set_bit(STRIPE_IO_STARTED, &sh->state);
1166
1167                         bio_set_dev(rbi, rrdev->bdev);
1168                         bio_set_op_attrs(rbi, op, op_flags);
1169                         BUG_ON(!op_is_write(op));
1170                         rbi->bi_end_io = raid5_end_write_request;
1171                         rbi->bi_private = sh;
1172
1173                         pr_debug("%s: for %llu schedule op %d on "
1174                                  "replacement disc %d\n",
1175                                 __func__, (unsigned long long)sh->sector,
1176                                 rbi->bi_opf, i);
1177                         atomic_inc(&sh->count);
1178                         if (sh != head_sh)
1179                                 atomic_inc(&head_sh->count);
1180                         if (use_new_offset(conf, sh))
1181                                 rbi->bi_iter.bi_sector = (sh->sector
1182                                                   + rrdev->new_data_offset);
1183                         else
1184                                 rbi->bi_iter.bi_sector = (sh->sector
1185                                                   + rrdev->data_offset);
1186                         if (test_bit(R5_SkipCopy, &sh->dev[i].flags))
1187                                 WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
1188                         sh->dev[i].rvec.bv_page = sh->dev[i].page;
1189                         rbi->bi_vcnt = 1;
1190                         rbi->bi_io_vec[0].bv_len = STRIPE_SIZE;
1191                         rbi->bi_io_vec[0].bv_offset = 0;
1192                         rbi->bi_iter.bi_size = STRIPE_SIZE;
1193                         /*
1194                          * If this is discard request, set bi_vcnt 0. We don't
1195                          * want to confuse SCSI because SCSI will replace payload
1196                          */
1197                         if (op == REQ_OP_DISCARD)
1198                                 rbi->bi_vcnt = 0;
1199                         if (conf->mddev->gendisk)
1200                                 trace_block_bio_remap(rbi->bi_disk->queue,
1201                                                       rbi, disk_devt(conf->mddev->gendisk),
1202                                                       sh->dev[i].sector);
1203                         if (should_defer && op_is_write(op))
1204                                 bio_list_add(&pending_bios, rbi);
1205                         else
1206                                 generic_make_request(rbi);
1207                 }
1208                 if (!rdev && !rrdev) {
1209                         if (op_is_write(op))
1210                                 set_bit(STRIPE_DEGRADED, &sh->state);
1211                         pr_debug("skip op %d on disc %d for sector %llu\n",
1212                                 bi->bi_opf, i, (unsigned long long)sh->sector);
1213                         clear_bit(R5_LOCKED, &sh->dev[i].flags);
1214                         set_bit(STRIPE_HANDLE, &sh->state);
1215                 }
1216
1217                 if (!head_sh->batch_head)
1218                         continue;
1219                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1220                                       batch_list);
1221                 if (sh != head_sh)
1222                         goto again;
1223         }
1224
1225         if (should_defer && !bio_list_empty(&pending_bios))
1226                 defer_issue_bios(conf, head_sh->sector, &pending_bios);
1227 }
1228
1229 static struct dma_async_tx_descriptor *
1230 async_copy_data(int frombio, struct bio *bio, struct page **page,
1231         sector_t sector, struct dma_async_tx_descriptor *tx,
1232         struct stripe_head *sh, int no_skipcopy)
1233 {
1234         struct bio_vec bvl;
1235         struct bvec_iter iter;
1236         struct page *bio_page;
1237         int page_offset;
1238         struct async_submit_ctl submit;
1239         enum async_tx_flags flags = 0;
1240
1241         if (bio->bi_iter.bi_sector >= sector)
1242                 page_offset = (signed)(bio->bi_iter.bi_sector - sector) * 512;
1243         else
1244                 page_offset = (signed)(sector - bio->bi_iter.bi_sector) * -512;
1245
1246         if (frombio)
1247                 flags |= ASYNC_TX_FENCE;
1248         init_async_submit(&submit, flags, tx, NULL, NULL, NULL);
1249
1250         bio_for_each_segment(bvl, bio, iter) {
1251                 int len = bvl.bv_len;
1252                 int clen;
1253                 int b_offset = 0;
1254
1255                 if (page_offset < 0) {
1256                         b_offset = -page_offset;
1257                         page_offset += b_offset;
1258                         len -= b_offset;
1259                 }
1260
1261                 if (len > 0 && page_offset + len > STRIPE_SIZE)
1262                         clen = STRIPE_SIZE - page_offset;
1263                 else
1264                         clen = len;
1265
1266                 if (clen > 0) {
1267                         b_offset += bvl.bv_offset;
1268                         bio_page = bvl.bv_page;
1269                         if (frombio) {
1270                                 if (sh->raid_conf->skip_copy &&
1271                                     b_offset == 0 && page_offset == 0 &&
1272                                     clen == STRIPE_SIZE &&
1273                                     !no_skipcopy)
1274                                         *page = bio_page;
1275                                 else
1276                                         tx = async_memcpy(*page, bio_page, page_offset,
1277                                                   b_offset, clen, &submit);
1278                         } else
1279                                 tx = async_memcpy(bio_page, *page, b_offset,
1280                                                   page_offset, clen, &submit);
1281                 }
1282                 /* chain the operations */
1283                 submit.depend_tx = tx;
1284
1285                 if (clen < len) /* hit end of page */
1286                         break;
1287                 page_offset +=  len;
1288         }
1289
1290         return tx;
1291 }
1292
1293 static void ops_complete_biofill(void *stripe_head_ref)
1294 {
1295         struct stripe_head *sh = stripe_head_ref;
1296         int i;
1297
1298         pr_debug("%s: stripe %llu\n", __func__,
1299                 (unsigned long long)sh->sector);
1300
1301         /* clear completed biofills */
1302         for (i = sh->disks; i--; ) {
1303                 struct r5dev *dev = &sh->dev[i];
1304
1305                 /* acknowledge completion of a biofill operation */
1306                 /* and check if we need to reply to a read request,
1307                  * new R5_Wantfill requests are held off until
1308                  * !STRIPE_BIOFILL_RUN
1309                  */
1310                 if (test_and_clear_bit(R5_Wantfill, &dev->flags)) {
1311                         struct bio *rbi, *rbi2;
1312
1313                         BUG_ON(!dev->read);
1314                         rbi = dev->read;
1315                         dev->read = NULL;
1316                         while (rbi && rbi->bi_iter.bi_sector <
1317                                 dev->sector + STRIPE_SECTORS) {
1318                                 rbi2 = r5_next_bio(rbi, dev->sector);
1319                                 bio_endio(rbi);
1320                                 rbi = rbi2;
1321                         }
1322                 }
1323         }
1324         clear_bit(STRIPE_BIOFILL_RUN, &sh->state);
1325
1326         set_bit(STRIPE_HANDLE, &sh->state);
1327         raid5_release_stripe(sh);
1328 }
1329
1330 static void ops_run_biofill(struct stripe_head *sh)
1331 {
1332         struct dma_async_tx_descriptor *tx = NULL;
1333         struct async_submit_ctl submit;
1334         int i;
1335
1336         BUG_ON(sh->batch_head);
1337         pr_debug("%s: stripe %llu\n", __func__,
1338                 (unsigned long long)sh->sector);
1339
1340         for (i = sh->disks; i--; ) {
1341                 struct r5dev *dev = &sh->dev[i];
1342                 if (test_bit(R5_Wantfill, &dev->flags)) {
1343                         struct bio *rbi;
1344                         spin_lock_irq(&sh->stripe_lock);
1345                         dev->read = rbi = dev->toread;
1346                         dev->toread = NULL;
1347                         spin_unlock_irq(&sh->stripe_lock);
1348                         while (rbi && rbi->bi_iter.bi_sector <
1349                                 dev->sector + STRIPE_SECTORS) {
1350                                 tx = async_copy_data(0, rbi, &dev->page,
1351                                                      dev->sector, tx, sh, 0);
1352                                 rbi = r5_next_bio(rbi, dev->sector);
1353                         }
1354                 }
1355         }
1356
1357         atomic_inc(&sh->count);
1358         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_biofill, sh, NULL);
1359         async_trigger_callback(&submit);
1360 }
1361
1362 static void mark_target_uptodate(struct stripe_head *sh, int target)
1363 {
1364         struct r5dev *tgt;
1365
1366         if (target < 0)
1367                 return;
1368
1369         tgt = &sh->dev[target];
1370         set_bit(R5_UPTODATE, &tgt->flags);
1371         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1372         clear_bit(R5_Wantcompute, &tgt->flags);
1373 }
1374
1375 static void ops_complete_compute(void *stripe_head_ref)
1376 {
1377         struct stripe_head *sh = stripe_head_ref;
1378
1379         pr_debug("%s: stripe %llu\n", __func__,
1380                 (unsigned long long)sh->sector);
1381
1382         /* mark the computed target(s) as uptodate */
1383         mark_target_uptodate(sh, sh->ops.target);
1384         mark_target_uptodate(sh, sh->ops.target2);
1385
1386         clear_bit(STRIPE_COMPUTE_RUN, &sh->state);
1387         if (sh->check_state == check_state_compute_run)
1388                 sh->check_state = check_state_compute_result;
1389         set_bit(STRIPE_HANDLE, &sh->state);
1390         raid5_release_stripe(sh);
1391 }
1392
1393 /* return a pointer to the address conversion region of the scribble buffer */
1394 static addr_conv_t *to_addr_conv(struct stripe_head *sh,
1395                                  struct raid5_percpu *percpu, int i)
1396 {
1397         void *addr;
1398
1399         addr = flex_array_get(percpu->scribble, i);
1400         return addr + sizeof(struct page *) * (sh->disks + 2);
1401 }
1402
1403 /* return a pointer to the address conversion region of the scribble buffer */
1404 static struct page **to_addr_page(struct raid5_percpu *percpu, int i)
1405 {
1406         void *addr;
1407
1408         addr = flex_array_get(percpu->scribble, i);
1409         return addr;
1410 }
1411
1412 static struct dma_async_tx_descriptor *
1413 ops_run_compute5(struct stripe_head *sh, struct raid5_percpu *percpu)
1414 {
1415         int disks = sh->disks;
1416         struct page **xor_srcs = to_addr_page(percpu, 0);
1417         int target = sh->ops.target;
1418         struct r5dev *tgt = &sh->dev[target];
1419         struct page *xor_dest = tgt->page;
1420         int count = 0;
1421         struct dma_async_tx_descriptor *tx;
1422         struct async_submit_ctl submit;
1423         int i;
1424
1425         BUG_ON(sh->batch_head);
1426
1427         pr_debug("%s: stripe %llu block: %d\n",
1428                 __func__, (unsigned long long)sh->sector, target);
1429         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1430
1431         for (i = disks; i--; )
1432                 if (i != target)
1433                         xor_srcs[count++] = sh->dev[i].page;
1434
1435         atomic_inc(&sh->count);
1436
1437         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, NULL,
1438                           ops_complete_compute, sh, to_addr_conv(sh, percpu, 0));
1439         if (unlikely(count == 1))
1440                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1441         else
1442                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1443
1444         return tx;
1445 }
1446
1447 /* set_syndrome_sources - populate source buffers for gen_syndrome
1448  * @srcs - (struct page *) array of size sh->disks
1449  * @sh - stripe_head to parse
1450  *
1451  * Populates srcs in proper layout order for the stripe and returns the
1452  * 'count' of sources to be used in a call to async_gen_syndrome.  The P
1453  * destination buffer is recorded in srcs[count] and the Q destination
1454  * is recorded in srcs[count+1]].
1455  */
1456 static int set_syndrome_sources(struct page **srcs,
1457                                 struct stripe_head *sh,
1458                                 int srctype)
1459 {
1460         int disks = sh->disks;
1461         int syndrome_disks = sh->ddf_layout ? disks : (disks - 2);
1462         int d0_idx = raid6_d0(sh);
1463         int count;
1464         int i;
1465
1466         for (i = 0; i < disks; i++)
1467                 srcs[i] = NULL;
1468
1469         count = 0;
1470         i = d0_idx;
1471         do {
1472                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1473                 struct r5dev *dev = &sh->dev[i];
1474
1475                 if (i == sh->qd_idx || i == sh->pd_idx ||
1476                     (srctype == SYNDROME_SRC_ALL) ||
1477                     (srctype == SYNDROME_SRC_WANT_DRAIN &&
1478                      (test_bit(R5_Wantdrain, &dev->flags) ||
1479                       test_bit(R5_InJournal, &dev->flags))) ||
1480                     (srctype == SYNDROME_SRC_WRITTEN &&
1481                      (dev->written ||
1482                       test_bit(R5_InJournal, &dev->flags)))) {
1483                         if (test_bit(R5_InJournal, &dev->flags))
1484                                 srcs[slot] = sh->dev[i].orig_page;
1485                         else
1486                                 srcs[slot] = sh->dev[i].page;
1487                 }
1488                 i = raid6_next_disk(i, disks);
1489         } while (i != d0_idx);
1490
1491         return syndrome_disks;
1492 }
1493
1494 static struct dma_async_tx_descriptor *
1495 ops_run_compute6_1(struct stripe_head *sh, struct raid5_percpu *percpu)
1496 {
1497         int disks = sh->disks;
1498         struct page **blocks = to_addr_page(percpu, 0);
1499         int target;
1500         int qd_idx = sh->qd_idx;
1501         struct dma_async_tx_descriptor *tx;
1502         struct async_submit_ctl submit;
1503         struct r5dev *tgt;
1504         struct page *dest;
1505         int i;
1506         int count;
1507
1508         BUG_ON(sh->batch_head);
1509         if (sh->ops.target < 0)
1510                 target = sh->ops.target2;
1511         else if (sh->ops.target2 < 0)
1512                 target = sh->ops.target;
1513         else
1514                 /* we should only have one valid target */
1515                 BUG();
1516         BUG_ON(target < 0);
1517         pr_debug("%s: stripe %llu block: %d\n",
1518                 __func__, (unsigned long long)sh->sector, target);
1519
1520         tgt = &sh->dev[target];
1521         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1522         dest = tgt->page;
1523
1524         atomic_inc(&sh->count);
1525
1526         if (target == qd_idx) {
1527                 count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1528                 blocks[count] = NULL; /* regenerating p is not necessary */
1529                 BUG_ON(blocks[count+1] != dest); /* q should already be set */
1530                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1531                                   ops_complete_compute, sh,
1532                                   to_addr_conv(sh, percpu, 0));
1533                 tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE, &submit);
1534         } else {
1535                 /* Compute any data- or p-drive using XOR */
1536                 count = 0;
1537                 for (i = disks; i-- ; ) {
1538                         if (i == target || i == qd_idx)
1539                                 continue;
1540                         blocks[count++] = sh->dev[i].page;
1541                 }
1542
1543                 init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1544                                   NULL, ops_complete_compute, sh,
1545                                   to_addr_conv(sh, percpu, 0));
1546                 tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE, &submit);
1547         }
1548
1549         return tx;
1550 }
1551
1552 static struct dma_async_tx_descriptor *
1553 ops_run_compute6_2(struct stripe_head *sh, struct raid5_percpu *percpu)
1554 {
1555         int i, count, disks = sh->disks;
1556         int syndrome_disks = sh->ddf_layout ? disks : disks-2;
1557         int d0_idx = raid6_d0(sh);
1558         int faila = -1, failb = -1;
1559         int target = sh->ops.target;
1560         int target2 = sh->ops.target2;
1561         struct r5dev *tgt = &sh->dev[target];
1562         struct r5dev *tgt2 = &sh->dev[target2];
1563         struct dma_async_tx_descriptor *tx;
1564         struct page **blocks = to_addr_page(percpu, 0);
1565         struct async_submit_ctl submit;
1566
1567         BUG_ON(sh->batch_head);
1568         pr_debug("%s: stripe %llu block1: %d block2: %d\n",
1569                  __func__, (unsigned long long)sh->sector, target, target2);
1570         BUG_ON(target < 0 || target2 < 0);
1571         BUG_ON(!test_bit(R5_Wantcompute, &tgt->flags));
1572         BUG_ON(!test_bit(R5_Wantcompute, &tgt2->flags));
1573
1574         /* we need to open-code set_syndrome_sources to handle the
1575          * slot number conversion for 'faila' and 'failb'
1576          */
1577         for (i = 0; i < disks ; i++)
1578                 blocks[i] = NULL;
1579         count = 0;
1580         i = d0_idx;
1581         do {
1582                 int slot = raid6_idx_to_slot(i, sh, &count, syndrome_disks);
1583
1584                 blocks[slot] = sh->dev[i].page;
1585
1586                 if (i == target)
1587                         faila = slot;
1588                 if (i == target2)
1589                         failb = slot;
1590                 i = raid6_next_disk(i, disks);
1591         } while (i != d0_idx);
1592
1593         BUG_ON(faila == failb);
1594         if (failb < faila)
1595                 swap(faila, failb);
1596         pr_debug("%s: stripe: %llu faila: %d failb: %d\n",
1597                  __func__, (unsigned long long)sh->sector, faila, failb);
1598
1599         atomic_inc(&sh->count);
1600
1601         if (failb == syndrome_disks+1) {
1602                 /* Q disk is one of the missing disks */
1603                 if (faila == syndrome_disks) {
1604                         /* Missing P+Q, just recompute */
1605                         init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1606                                           ops_complete_compute, sh,
1607                                           to_addr_conv(sh, percpu, 0));
1608                         return async_gen_syndrome(blocks, 0, syndrome_disks+2,
1609                                                   STRIPE_SIZE, &submit);
1610                 } else {
1611                         struct page *dest;
1612                         int data_target;
1613                         int qd_idx = sh->qd_idx;
1614
1615                         /* Missing D+Q: recompute D from P, then recompute Q */
1616                         if (target == qd_idx)
1617                                 data_target = target2;
1618                         else
1619                                 data_target = target;
1620
1621                         count = 0;
1622                         for (i = disks; i-- ; ) {
1623                                 if (i == data_target || i == qd_idx)
1624                                         continue;
1625                                 blocks[count++] = sh->dev[i].page;
1626                         }
1627                         dest = sh->dev[data_target].page;
1628                         init_async_submit(&submit,
1629                                           ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST,
1630                                           NULL, NULL, NULL,
1631                                           to_addr_conv(sh, percpu, 0));
1632                         tx = async_xor(dest, blocks, 0, count, STRIPE_SIZE,
1633                                        &submit);
1634
1635                         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_ALL);
1636                         init_async_submit(&submit, ASYNC_TX_FENCE, tx,
1637                                           ops_complete_compute, sh,
1638                                           to_addr_conv(sh, percpu, 0));
1639                         return async_gen_syndrome(blocks, 0, count+2,
1640                                                   STRIPE_SIZE, &submit);
1641                 }
1642         } else {
1643                 init_async_submit(&submit, ASYNC_TX_FENCE, NULL,
1644                                   ops_complete_compute, sh,
1645                                   to_addr_conv(sh, percpu, 0));
1646                 if (failb == syndrome_disks) {
1647                         /* We're missing D+P. */
1648                         return async_raid6_datap_recov(syndrome_disks+2,
1649                                                        STRIPE_SIZE, faila,
1650                                                        blocks, &submit);
1651                 } else {
1652                         /* We're missing D+D. */
1653                         return async_raid6_2data_recov(syndrome_disks+2,
1654                                                        STRIPE_SIZE, faila, failb,
1655                                                        blocks, &submit);
1656                 }
1657         }
1658 }
1659
1660 static void ops_complete_prexor(void *stripe_head_ref)
1661 {
1662         struct stripe_head *sh = stripe_head_ref;
1663
1664         pr_debug("%s: stripe %llu\n", __func__,
1665                 (unsigned long long)sh->sector);
1666
1667         if (r5c_is_writeback(sh->raid_conf->log))
1668                 /*
1669                  * raid5-cache write back uses orig_page during prexor.
1670                  * After prexor, it is time to free orig_page
1671                  */
1672                 r5c_release_extra_page(sh);
1673 }
1674
1675 static struct dma_async_tx_descriptor *
1676 ops_run_prexor5(struct stripe_head *sh, struct raid5_percpu *percpu,
1677                 struct dma_async_tx_descriptor *tx)
1678 {
1679         int disks = sh->disks;
1680         struct page **xor_srcs = to_addr_page(percpu, 0);
1681         int count = 0, pd_idx = sh->pd_idx, i;
1682         struct async_submit_ctl submit;
1683
1684         /* existing parity data subtracted */
1685         struct page *xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1686
1687         BUG_ON(sh->batch_head);
1688         pr_debug("%s: stripe %llu\n", __func__,
1689                 (unsigned long long)sh->sector);
1690
1691         for (i = disks; i--; ) {
1692                 struct r5dev *dev = &sh->dev[i];
1693                 /* Only process blocks that are known to be uptodate */
1694                 if (test_bit(R5_InJournal, &dev->flags))
1695                         xor_srcs[count++] = dev->orig_page;
1696                 else if (test_bit(R5_Wantdrain, &dev->flags))
1697                         xor_srcs[count++] = dev->page;
1698         }
1699
1700         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_DROP_DST, tx,
1701                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1702         tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1703
1704         return tx;
1705 }
1706
1707 static struct dma_async_tx_descriptor *
1708 ops_run_prexor6(struct stripe_head *sh, struct raid5_percpu *percpu,
1709                 struct dma_async_tx_descriptor *tx)
1710 {
1711         struct page **blocks = to_addr_page(percpu, 0);
1712         int count;
1713         struct async_submit_ctl submit;
1714
1715         pr_debug("%s: stripe %llu\n", __func__,
1716                 (unsigned long long)sh->sector);
1717
1718         count = set_syndrome_sources(blocks, sh, SYNDROME_SRC_WANT_DRAIN);
1719
1720         init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_PQ_XOR_DST, tx,
1721                           ops_complete_prexor, sh, to_addr_conv(sh, percpu, 0));
1722         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1723
1724         return tx;
1725 }
1726
1727 static struct dma_async_tx_descriptor *
1728 ops_run_biodrain(struct stripe_head *sh, struct dma_async_tx_descriptor *tx)
1729 {
1730         struct r5conf *conf = sh->raid_conf;
1731         int disks = sh->disks;
1732         int i;
1733         struct stripe_head *head_sh = sh;
1734
1735         pr_debug("%s: stripe %llu\n", __func__,
1736                 (unsigned long long)sh->sector);
1737
1738         for (i = disks; i--; ) {
1739                 struct r5dev *dev;
1740                 struct bio *chosen;
1741
1742                 sh = head_sh;
1743                 if (test_and_clear_bit(R5_Wantdrain, &head_sh->dev[i].flags)) {
1744                         struct bio *wbi;
1745
1746 again:
1747                         dev = &sh->dev[i];
1748                         /*
1749                          * clear R5_InJournal, so when rewriting a page in
1750                          * journal, it is not skipped by r5l_log_stripe()
1751                          */
1752                         clear_bit(R5_InJournal, &dev->flags);
1753                         spin_lock_irq(&sh->stripe_lock);
1754                         chosen = dev->towrite;
1755                         dev->towrite = NULL;
1756                         sh->overwrite_disks = 0;
1757                         BUG_ON(dev->written);
1758                         wbi = dev->written = chosen;
1759                         spin_unlock_irq(&sh->stripe_lock);
1760                         WARN_ON(dev->page != dev->orig_page);
1761
1762                         while (wbi && wbi->bi_iter.bi_sector <
1763                                 dev->sector + STRIPE_SECTORS) {
1764                                 if (wbi->bi_opf & REQ_FUA)
1765                                         set_bit(R5_WantFUA, &dev->flags);
1766                                 if (wbi->bi_opf & REQ_SYNC)
1767                                         set_bit(R5_SyncIO, &dev->flags);
1768                                 if (bio_op(wbi) == REQ_OP_DISCARD)
1769                                         set_bit(R5_Discard, &dev->flags);
1770                                 else {
1771                                         tx = async_copy_data(1, wbi, &dev->page,
1772                                                              dev->sector, tx, sh,
1773                                                              r5c_is_writeback(conf->log));
1774                                         if (dev->page != dev->orig_page &&
1775                                             !r5c_is_writeback(conf->log)) {
1776                                                 set_bit(R5_SkipCopy, &dev->flags);
1777                                                 clear_bit(R5_UPTODATE, &dev->flags);
1778                                                 clear_bit(R5_OVERWRITE, &dev->flags);
1779                                         }
1780                                 }
1781                                 wbi = r5_next_bio(wbi, dev->sector);
1782                         }
1783
1784                         if (head_sh->batch_head) {
1785                                 sh = list_first_entry(&sh->batch_list,
1786                                                       struct stripe_head,
1787                                                       batch_list);
1788                                 if (sh == head_sh)
1789                                         continue;
1790                                 goto again;
1791                         }
1792                 }
1793         }
1794
1795         return tx;
1796 }
1797
1798 static void ops_complete_reconstruct(void *stripe_head_ref)
1799 {
1800         struct stripe_head *sh = stripe_head_ref;
1801         int disks = sh->disks;
1802         int pd_idx = sh->pd_idx;
1803         int qd_idx = sh->qd_idx;
1804         int i;
1805         bool fua = false, sync = false, discard = false;
1806
1807         pr_debug("%s: stripe %llu\n", __func__,
1808                 (unsigned long long)sh->sector);
1809
1810         for (i = disks; i--; ) {
1811                 fua |= test_bit(R5_WantFUA, &sh->dev[i].flags);
1812                 sync |= test_bit(R5_SyncIO, &sh->dev[i].flags);
1813                 discard |= test_bit(R5_Discard, &sh->dev[i].flags);
1814         }
1815
1816         for (i = disks; i--; ) {
1817                 struct r5dev *dev = &sh->dev[i];
1818
1819                 if (dev->written || i == pd_idx || i == qd_idx) {
1820                         if (!discard && !test_bit(R5_SkipCopy, &dev->flags)) {
1821                                 set_bit(R5_UPTODATE, &dev->flags);
1822                                 if (test_bit(STRIPE_EXPAND_READY, &sh->state))
1823                                         set_bit(R5_Expanded, &dev->flags);
1824                         }
1825                         if (fua)
1826                                 set_bit(R5_WantFUA, &dev->flags);
1827                         if (sync)
1828                                 set_bit(R5_SyncIO, &dev->flags);
1829                 }
1830         }
1831
1832         if (sh->reconstruct_state == reconstruct_state_drain_run)
1833                 sh->reconstruct_state = reconstruct_state_drain_result;
1834         else if (sh->reconstruct_state == reconstruct_state_prexor_drain_run)
1835                 sh->reconstruct_state = reconstruct_state_prexor_drain_result;
1836         else {
1837                 BUG_ON(sh->reconstruct_state != reconstruct_state_run);
1838                 sh->reconstruct_state = reconstruct_state_result;
1839         }
1840
1841         set_bit(STRIPE_HANDLE, &sh->state);
1842         raid5_release_stripe(sh);
1843 }
1844
1845 static void
1846 ops_run_reconstruct5(struct stripe_head *sh, struct raid5_percpu *percpu,
1847                      struct dma_async_tx_descriptor *tx)
1848 {
1849         int disks = sh->disks;
1850         struct page **xor_srcs;
1851         struct async_submit_ctl submit;
1852         int count, pd_idx = sh->pd_idx, i;
1853         struct page *xor_dest;
1854         int prexor = 0;
1855         unsigned long flags;
1856         int j = 0;
1857         struct stripe_head *head_sh = sh;
1858         int last_stripe;
1859
1860         pr_debug("%s: stripe %llu\n", __func__,
1861                 (unsigned long long)sh->sector);
1862
1863         for (i = 0; i < sh->disks; i++) {
1864                 if (pd_idx == i)
1865                         continue;
1866                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1867                         break;
1868         }
1869         if (i >= sh->disks) {
1870                 atomic_inc(&sh->count);
1871                 set_bit(R5_Discard, &sh->dev[pd_idx].flags);
1872                 ops_complete_reconstruct(sh);
1873                 return;
1874         }
1875 again:
1876         count = 0;
1877         xor_srcs = to_addr_page(percpu, j);
1878         /* check if prexor is active which means only process blocks
1879          * that are part of a read-modify-write (written)
1880          */
1881         if (head_sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1882                 prexor = 1;
1883                 xor_dest = xor_srcs[count++] = sh->dev[pd_idx].page;
1884                 for (i = disks; i--; ) {
1885                         struct r5dev *dev = &sh->dev[i];
1886                         if (head_sh->dev[i].written ||
1887                             test_bit(R5_InJournal, &head_sh->dev[i].flags))
1888                                 xor_srcs[count++] = dev->page;
1889                 }
1890         } else {
1891                 xor_dest = sh->dev[pd_idx].page;
1892                 for (i = disks; i--; ) {
1893                         struct r5dev *dev = &sh->dev[i];
1894                         if (i != pd_idx)
1895                                 xor_srcs[count++] = dev->page;
1896                 }
1897         }
1898
1899         /* 1/ if we prexor'd then the dest is reused as a source
1900          * 2/ if we did not prexor then we are redoing the parity
1901          * set ASYNC_TX_XOR_DROP_DST and ASYNC_TX_XOR_ZERO_DST
1902          * for the synchronous xor case
1903          */
1904         last_stripe = !head_sh->batch_head ||
1905                 list_first_entry(&sh->batch_list,
1906                                  struct stripe_head, batch_list) == head_sh;
1907         if (last_stripe) {
1908                 flags = ASYNC_TX_ACK |
1909                         (prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST);
1910
1911                 atomic_inc(&head_sh->count);
1912                 init_async_submit(&submit, flags, tx, ops_complete_reconstruct, head_sh,
1913                                   to_addr_conv(sh, percpu, j));
1914         } else {
1915                 flags = prexor ? ASYNC_TX_XOR_DROP_DST : ASYNC_TX_XOR_ZERO_DST;
1916                 init_async_submit(&submit, flags, tx, NULL, NULL,
1917                                   to_addr_conv(sh, percpu, j));
1918         }
1919
1920         if (unlikely(count == 1))
1921                 tx = async_memcpy(xor_dest, xor_srcs[0], 0, 0, STRIPE_SIZE, &submit);
1922         else
1923                 tx = async_xor(xor_dest, xor_srcs, 0, count, STRIPE_SIZE, &submit);
1924         if (!last_stripe) {
1925                 j++;
1926                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1927                                       batch_list);
1928                 goto again;
1929         }
1930 }
1931
1932 static void
1933 ops_run_reconstruct6(struct stripe_head *sh, struct raid5_percpu *percpu,
1934                      struct dma_async_tx_descriptor *tx)
1935 {
1936         struct async_submit_ctl submit;
1937         struct page **blocks;
1938         int count, i, j = 0;
1939         struct stripe_head *head_sh = sh;
1940         int last_stripe;
1941         int synflags;
1942         unsigned long txflags;
1943
1944         pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
1945
1946         for (i = 0; i < sh->disks; i++) {
1947                 if (sh->pd_idx == i || sh->qd_idx == i)
1948                         continue;
1949                 if (!test_bit(R5_Discard, &sh->dev[i].flags))
1950                         break;
1951         }
1952         if (i >= sh->disks) {
1953                 atomic_inc(&sh->count);
1954                 set_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
1955                 set_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
1956                 ops_complete_reconstruct(sh);
1957                 return;
1958         }
1959
1960 again:
1961         blocks = to_addr_page(percpu, j);
1962
1963         if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
1964                 synflags = SYNDROME_SRC_WRITTEN;
1965                 txflags = ASYNC_TX_ACK | ASYNC_TX_PQ_XOR_DST;
1966         } else {
1967                 synflags = SYNDROME_SRC_ALL;
1968                 txflags = ASYNC_TX_ACK;
1969         }
1970
1971         count = set_syndrome_sources(blocks, sh, synflags);
1972         last_stripe = !head_sh->batch_head ||
1973                 list_first_entry(&sh->batch_list,
1974                                  struct stripe_head, batch_list) == head_sh;
1975
1976         if (last_stripe) {
1977                 atomic_inc(&head_sh->count);
1978                 init_async_submit(&submit, txflags, tx, ops_complete_reconstruct,
1979                                   head_sh, to_addr_conv(sh, percpu, j));
1980         } else
1981                 init_async_submit(&submit, 0, tx, NULL, NULL,
1982                                   to_addr_conv(sh, percpu, j));
1983         tx = async_gen_syndrome(blocks, 0, count+2, STRIPE_SIZE,  &submit);
1984         if (!last_stripe) {
1985                 j++;
1986                 sh = list_first_entry(&sh->batch_list, struct stripe_head,
1987                                       batch_list);
1988                 goto again;
1989         }
1990 }
1991
1992 static void ops_complete_check(void *stripe_head_ref)
1993 {
1994         struct stripe_head *sh = stripe_head_ref;
1995
1996         pr_debug("%s: stripe %llu\n", __func__,
1997                 (unsigned long long)sh->sector);
1998
1999         sh->check_state = check_state_check_result;
2000         set_bit(STRIPE_HANDLE, &sh->state);
2001         raid5_release_stripe(sh);
2002 }
2003
2004 static void ops_run_check_p(struct stripe_head *sh, struct raid5_percpu *percpu)
2005 {
2006         int disks = sh->disks;
2007         int pd_idx = sh->pd_idx;
2008         int qd_idx = sh->qd_idx;
2009         struct page *xor_dest;
2010         struct page **xor_srcs = to_addr_page(percpu, 0);
2011         struct dma_async_tx_descriptor *tx;
2012         struct async_submit_ctl submit;
2013         int count;
2014         int i;
2015
2016         pr_debug("%s: stripe %llu\n", __func__,
2017                 (unsigned long long)sh->sector);
2018
2019         BUG_ON(sh->batch_head);
2020         count = 0;
2021         xor_dest = sh->dev[pd_idx].page;
2022         xor_srcs[count++] = xor_dest;
2023         for (i = disks; i--; ) {
2024                 if (i == pd_idx || i == qd_idx)
2025                         continue;
2026                 xor_srcs[count++] = sh->dev[i].page;
2027         }
2028
2029         init_async_submit(&submit, 0, NULL, NULL, NULL,
2030                           to_addr_conv(sh, percpu, 0));
2031         tx = async_xor_val(xor_dest, xor_srcs, 0, count, STRIPE_SIZE,
2032                            &sh->ops.zero_sum_result, &submit);
2033
2034         atomic_inc(&sh->count);
2035         init_async_submit(&submit, ASYNC_TX_ACK, tx, ops_complete_check, sh, NULL);
2036         tx = async_trigger_callback(&submit);
2037 }
2038
2039 static void ops_run_check_pq(struct stripe_head *sh, struct raid5_percpu *percpu, int checkp)
2040 {
2041         struct page **srcs = to_addr_page(percpu, 0);
2042         struct async_submit_ctl submit;
2043         int count;
2044
2045         pr_debug("%s: stripe %llu checkp: %d\n", __func__,
2046                 (unsigned long long)sh->sector, checkp);
2047
2048         BUG_ON(sh->batch_head);
2049         count = set_syndrome_sources(srcs, sh, SYNDROME_SRC_ALL);
2050         if (!checkp)
2051                 srcs[count] = NULL;
2052
2053         atomic_inc(&sh->count);
2054         init_async_submit(&submit, ASYNC_TX_ACK, NULL, ops_complete_check,
2055                           sh, to_addr_conv(sh, percpu, 0));
2056         async_syndrome_val(srcs, 0, count+2, STRIPE_SIZE,
2057                            &sh->ops.zero_sum_result, percpu->spare_page, &submit);
2058 }
2059
2060 static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request)
2061 {
2062         int overlap_clear = 0, i, disks = sh->disks;
2063         struct dma_async_tx_descriptor *tx = NULL;
2064         struct r5conf *conf = sh->raid_conf;
2065         int level = conf->level;
2066         struct raid5_percpu *percpu;
2067         unsigned long cpu;
2068
2069         cpu = get_cpu();
2070         percpu = per_cpu_ptr(conf->percpu, cpu);
2071         if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
2072                 ops_run_biofill(sh);
2073                 overlap_clear++;
2074         }
2075
2076         if (test_bit(STRIPE_OP_COMPUTE_BLK, &ops_request)) {
2077                 if (level < 6)
2078                         tx = ops_run_compute5(sh, percpu);
2079                 else {
2080                         if (sh->ops.target2 < 0 || sh->ops.target < 0)
2081                                 tx = ops_run_compute6_1(sh, percpu);
2082                         else
2083                                 tx = ops_run_compute6_2(sh, percpu);
2084                 }
2085                 /* terminate the chain if reconstruct is not set to be run */
2086                 if (tx && !test_bit(STRIPE_OP_RECONSTRUCT, &ops_request))
2087                         async_tx_ack(tx);
2088         }
2089
2090         if (test_bit(STRIPE_OP_PREXOR, &ops_request)) {
2091                 if (level < 6)
2092                         tx = ops_run_prexor5(sh, percpu, tx);
2093                 else
2094                         tx = ops_run_prexor6(sh, percpu, tx);
2095         }
2096
2097         if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request))
2098                 tx = ops_run_partial_parity(sh, percpu, tx);
2099
2100         if (test_bit(STRIPE_OP_BIODRAIN, &ops_request)) {
2101                 tx = ops_run_biodrain(sh, tx);
2102                 overlap_clear++;
2103         }
2104
2105         if (test_bit(STRIPE_OP_RECONSTRUCT, &ops_request)) {
2106                 if (level < 6)
2107                         ops_run_reconstruct5(sh, percpu, tx);
2108                 else
2109                         ops_run_reconstruct6(sh, percpu, tx);
2110         }
2111
2112         if (test_bit(STRIPE_OP_CHECK, &ops_request)) {
2113                 if (sh->check_state == check_state_run)
2114                         ops_run_check_p(sh, percpu);
2115                 else if (sh->check_state == check_state_run_q)
2116                         ops_run_check_pq(sh, percpu, 0);
2117                 else if (sh->check_state == check_state_run_pq)
2118                         ops_run_check_pq(sh, percpu, 1);
2119                 else
2120                         BUG();
2121         }
2122
2123         if (overlap_clear && !sh->batch_head)
2124                 for (i = disks; i--; ) {
2125                         struct r5dev *dev = &sh->dev[i];
2126                         if (test_and_clear_bit(R5_Overlap, &dev->flags))
2127                                 wake_up(&sh->raid_conf->wait_for_overlap);
2128                 }
2129         put_cpu();
2130 }
2131
2132 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
2133 {
2134         if (sh->ppl_page)
2135                 __free_page(sh->ppl_page);
2136         kmem_cache_free(sc, sh);
2137 }
2138
2139 static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,
2140         int disks, struct r5conf *conf)
2141 {
2142         struct stripe_head *sh;
2143         int i;
2144
2145         sh = kmem_cache_zalloc(sc, gfp);
2146         if (sh) {
2147                 spin_lock_init(&sh->stripe_lock);
2148                 spin_lock_init(&sh->batch_lock);
2149                 INIT_LIST_HEAD(&sh->batch_list);
2150                 INIT_LIST_HEAD(&sh->lru);
2151                 INIT_LIST_HEAD(&sh->r5c);
2152                 INIT_LIST_HEAD(&sh->log_list);
2153                 atomic_set(&sh->count, 1);
2154                 sh->raid_conf = conf;
2155                 sh->log_start = MaxSector;
2156                 for (i = 0; i < disks; i++) {
2157                         struct r5dev *dev = &sh->dev[i];
2158
2159                         bio_init(&dev->req, &dev->vec, 1);
2160                         bio_init(&dev->rreq, &dev->rvec, 1);
2161                 }
2162
2163                 if (raid5_has_ppl(conf)) {
2164                         sh->ppl_page = alloc_page(gfp);
2165                         if (!sh->ppl_page) {
2166                                 free_stripe(sc, sh);
2167                                 sh = NULL;
2168                         }
2169                 }
2170         }
2171         return sh;
2172 }
2173 static int grow_one_stripe(struct r5conf *conf, gfp_t gfp)
2174 {
2175         struct stripe_head *sh;
2176
2177         sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size, conf);
2178         if (!sh)
2179                 return 0;
2180
2181         if (grow_buffers(sh, gfp)) {
2182                 shrink_buffers(sh);
2183                 free_stripe(conf->slab_cache, sh);
2184                 return 0;
2185         }
2186         sh->hash_lock_index =
2187                 conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS;
2188         /* we just created an active stripe so... */
2189         atomic_inc(&conf->active_stripes);
2190
2191         raid5_release_stripe(sh);
2192         conf->max_nr_stripes++;
2193         return 1;
2194 }
2195
2196 static int grow_stripes(struct r5conf *conf, int num)
2197 {
2198         struct kmem_cache *sc;
2199         int devs = max(conf->raid_disks, conf->previous_raid_disks);
2200
2201         if (conf->mddev->gendisk)
2202                 sprintf(conf->cache_name[0],
2203                         "raid%d-%s", conf->level, mdname(conf->mddev));
2204         else
2205                 sprintf(conf->cache_name[0],
2206                         "raid%d-%p", conf->level, conf->mddev);
2207         sprintf(conf->cache_name[1], "%s-alt", conf->cache_name[0]);
2208
2209         conf->active_name = 0;
2210         sc = kmem_cache_create(conf->cache_name[conf->active_name],
2211                                sizeof(struct stripe_head)+(devs-1)*sizeof(struct r5dev),
2212                                0, 0, NULL);
2213         if (!sc)
2214                 return 1;
2215         conf->slab_cache = sc;
2216         conf->pool_size = devs;
2217         while (num--)
2218                 if (!grow_one_stripe(conf, GFP_KERNEL))
2219                         return 1;
2220
2221         return 0;
2222 }
2223
2224 /**
2225  * scribble_len - return the required size of the scribble region
2226  * @num - total number of disks in the array
2227  *
2228  * The size must be enough to contain:
2229  * 1/ a struct page pointer for each device in the array +2
2230  * 2/ room to convert each entry in (1) to its corresponding dma
2231  *    (dma_map_page()) or page (page_address()) address.
2232  *
2233  * Note: the +2 is for the destination buffers of the ddf/raid6 case where we
2234  * calculate over all devices (not just the data blocks), using zeros in place
2235  * of the P and Q blocks.
2236  */
2237 static struct flex_array *scribble_alloc(int num, int cnt, gfp_t flags)
2238 {
2239         struct flex_array *ret;
2240         size_t len;
2241
2242         len = sizeof(struct page *) * (num+2) + sizeof(addr_conv_t) * (num+2);
2243         ret = flex_array_alloc(len, cnt, flags);
2244         if (!ret)
2245                 return NULL;
2246         /* always prealloc all elements, so no locking is required */
2247         if (flex_array_prealloc(ret, 0, cnt, flags)) {
2248                 flex_array_free(ret);
2249                 return NULL;
2250         }
2251         return ret;
2252 }
2253
2254 static int resize_chunks(struct r5conf *conf, int new_disks, int new_sectors)
2255 {
2256         unsigned long cpu;
2257         int err = 0;
2258
2259         /*
2260          * Never shrink. And mddev_suspend() could deadlock if this is called
2261          * from raid5d. In that case, scribble_disks and scribble_sectors
2262          * should equal to new_disks and new_sectors
2263          */
2264         if (conf->scribble_disks >= new_disks &&
2265             conf->scribble_sectors >= new_sectors)
2266                 return 0;
2267         mddev_suspend(conf->mddev);
2268         get_online_cpus();
2269         for_each_present_cpu(cpu) {
2270                 struct raid5_percpu *percpu;
2271                 struct flex_array *scribble;
2272
2273                 percpu = per_cpu_ptr(conf->percpu, cpu);
2274                 scribble = scribble_alloc(new_disks,
2275                                           new_sectors / STRIPE_SECTORS,
2276                                           GFP_NOIO);
2277
2278                 if (scribble) {
2279                         flex_array_free(percpu->scribble);
2280                         percpu->scribble = scribble;
2281                 } else {
2282                         err = -ENOMEM;
2283                         break;
2284                 }
2285         }
2286         put_online_cpus();
2287         mddev_resume(conf->mddev);
2288         if (!err) {
2289                 conf->scribble_disks = new_disks;
2290                 conf->scribble_sectors = new_sectors;
2291         }
2292         return err;
2293 }
2294
2295 static int resize_stripes(struct r5conf *conf, int newsize)
2296 {
2297         /* Make all the stripes able to hold 'newsize' devices.
2298          * New slots in each stripe get 'page' set to a new page.
2299          *
2300          * This happens in stages:
2301          * 1/ create a new kmem_cache and allocate the required number of
2302          *    stripe_heads.
2303          * 2/ gather all the old stripe_heads and transfer the pages across
2304          *    to the new stripe_heads.  This will have the side effect of
2305          *    freezing the array as once all stripe_heads have been collected,
2306          *    no IO will be possible.  Old stripe heads are freed once their
2307          *    pages have been transferred over, and the old kmem_cache is
2308          *    freed when all stripes are done.
2309          * 3/ reallocate conf->disks to be suitable bigger.  If this fails,
2310          *    we simple return a failure status - no need to clean anything up.
2311          * 4/ allocate new pages for the new slots in the new stripe_heads.
2312          *    If this fails, we don't bother trying the shrink the
2313          *    stripe_heads down again, we just leave them as they are.
2314          *    As each stripe_head is processed the new one is released into
2315          *    active service.
2316          *
2317          * Once step2 is started, we cannot afford to wait for a write,
2318          * so we use GFP_NOIO allocations.
2319          */
2320         struct stripe_head *osh, *nsh;
2321         LIST_HEAD(newstripes);
2322         struct disk_info *ndisks;
2323         int err = 0;
2324         struct kmem_cache *sc;
2325         int i;
2326         int hash, cnt;
2327
2328         md_allow_write(conf->mddev);
2329
2330         /* Step 1 */
2331         sc = kmem_cache_create(conf->cache_name[1-conf->active_name],
2332                                sizeof(struct stripe_head)+(newsize-1)*sizeof(struct r5dev),
2333                                0, 0, NULL);
2334         if (!sc)
2335                 return -ENOMEM;
2336
2337         /* Need to ensure auto-resizing doesn't interfere */
2338         mutex_lock(&conf->cache_size_mutex);
2339
2340         for (i = conf->max_nr_stripes; i; i--) {
2341                 nsh = alloc_stripe(sc, GFP_KERNEL, newsize, conf);
2342                 if (!nsh)
2343                         break;
2344
2345                 list_add(&nsh->lru, &newstripes);
2346         }
2347         if (i) {
2348                 /* didn't get enough, give up */
2349                 while (!list_empty(&newstripes)) {
2350                         nsh = list_entry(newstripes.next, struct stripe_head, lru);
2351                         list_del(&nsh->lru);
2352                         free_stripe(sc, nsh);
2353                 }
2354                 kmem_cache_destroy(sc);
2355                 mutex_unlock(&conf->cache_size_mutex);
2356                 return -ENOMEM;
2357         }
2358         /* Step 2 - Must use GFP_NOIO now.
2359          * OK, we have enough stripes, start collecting inactive
2360          * stripes and copying them over
2361          */
2362         hash = 0;
2363         cnt = 0;
2364         list_for_each_entry(nsh, &newstripes, lru) {
2365                 lock_device_hash_lock(conf, hash);
2366                 wait_event_cmd(conf->wait_for_stripe,
2367                                     !list_empty(conf->inactive_list + hash),
2368                                     unlock_device_hash_lock(conf, hash),
2369                                     lock_device_hash_lock(conf, hash));
2370                 osh = get_free_stripe(conf, hash);
2371                 unlock_device_hash_lock(conf, hash);
2372
2373                 for(i=0; i<conf->pool_size; i++) {
2374                         nsh->dev[i].page = osh->dev[i].page;
2375                         nsh->dev[i].orig_page = osh->dev[i].page;
2376                 }
2377                 nsh->hash_lock_index = hash;
2378                 free_stripe(conf->slab_cache, osh);
2379                 cnt++;
2380                 if (cnt >= conf->max_nr_stripes / NR_STRIPE_HASH_LOCKS +
2381                     !!((conf->max_nr_stripes % NR_STRIPE_HASH_LOCKS) > hash)) {
2382                         hash++;
2383                         cnt = 0;
2384                 }
2385         }
2386         kmem_cache_destroy(conf->slab_cache);
2387
2388         /* Step 3.
2389          * At this point, we are holding all the stripes so the array
2390          * is completely stalled, so now is a good time to resize
2391          * conf->disks and the scribble region
2392          */
2393         ndisks = kzalloc(newsize * sizeof(struct disk_info), GFP_NOIO);
2394         if (ndisks) {
2395                 for (i = 0; i < conf->pool_size; i++)
2396                         ndisks[i] = conf->disks[i];
2397
2398                 for (i = conf->pool_size; i < newsize; i++) {
2399                         ndisks[i].extra_page = alloc_page(GFP_NOIO);
2400                         if (!ndisks[i].extra_page)
2401                                 err = -ENOMEM;
2402                 }
2403
2404                 if (err) {
2405                         for (i = conf->pool_size; i < newsize; i++)
2406                                 if (ndisks[i].extra_page)
2407                                         put_page(ndisks[i].extra_page);
2408                         kfree(ndisks);
2409                 } else {
2410                         kfree(conf->disks);
2411                         conf->disks = ndisks;
2412                 }
2413         } else
2414                 err = -ENOMEM;
2415
2416         mutex_unlock(&conf->cache_size_mutex);
2417
2418         conf->slab_cache = sc;
2419         conf->active_name = 1-conf->active_name;
2420
2421         /* Step 4, return new stripes to service */
2422         while(!list_empty(&newstripes)) {
2423                 nsh = list_entry(newstripes.next, struct stripe_head, lru);
2424                 list_del_init(&nsh->lru);
2425
2426                 for (i=conf->raid_disks; i < newsize; i++)
2427                         if (nsh->dev[i].page == NULL) {
2428                                 struct page *p = alloc_page(GFP_NOIO);
2429                                 nsh->dev[i].page = p;
2430                                 nsh->dev[i].orig_page = p;
2431                                 if (!p)
2432                                         err = -ENOMEM;
2433                         }
2434                 raid5_release_stripe(nsh);
2435         }
2436         /* critical section pass, GFP_NOIO no longer needed */
2437
2438         if (!err)
2439                 conf->pool_size = newsize;
2440         return err;
2441 }
2442
2443 static int drop_one_stripe(struct r5conf *conf)
2444 {
2445         struct stripe_head *sh;
2446         int hash = (conf->max_nr_stripes - 1) & STRIPE_HASH_LOCKS_MASK;
2447
2448         spin_lock_irq(conf->hash_locks + hash);
2449         sh = get_free_stripe(conf, hash);
2450         spin_unlock_irq(conf->hash_locks + hash);
2451         if (!sh)
2452                 return 0;
2453         BUG_ON(atomic_read(&sh->count));
2454         shrink_buffers(sh);
2455         free_stripe(conf->slab_cache, sh);
2456         atomic_dec(&conf->active_stripes);
2457         conf->max_nr_stripes--;
2458         return 1;
2459 }
2460
2461 static void shrink_stripes(struct r5conf *conf)
2462 {
2463         while (conf->max_nr_stripes &&
2464                drop_one_stripe(conf))
2465                 ;
2466
2467         kmem_cache_destroy(conf->slab_cache);
2468         conf->slab_cache = NULL;
2469 }
2470
2471 static void raid5_end_read_request(struct bio * bi)
2472 {
2473         struct stripe_head *sh = bi->bi_private;
2474         struct r5conf *conf = sh->raid_conf;
2475         int disks = sh->disks, i;
2476         char b[BDEVNAME_SIZE];
2477         struct md_rdev *rdev = NULL;
2478         sector_t s;
2479
2480         for (i=0 ; i<disks; i++)
2481                 if (bi == &sh->dev[i].req)
2482                         break;
2483
2484         pr_debug("end_read_request %llu/%d, count: %d, error %d.\n",
2485                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2486                 bi->bi_status);
2487         if (i == disks) {
2488                 bio_reset(bi);
2489                 BUG();
2490                 return;
2491         }
2492         if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2493                 /* If replacement finished while this request was outstanding,
2494                  * 'replacement' might be NULL already.
2495                  * In that case it moved down to 'rdev'.
2496                  * rdev is not removed until all requests are finished.
2497                  */
2498                 rdev = conf->disks[i].replacement;
2499         if (!rdev)
2500                 rdev = conf->disks[i].rdev;
2501
2502         if (use_new_offset(conf, sh))
2503                 s = sh->sector + rdev->new_data_offset;
2504         else
2505                 s = sh->sector + rdev->data_offset;
2506         if (!bi->bi_status) {
2507                 set_bit(R5_UPTODATE, &sh->dev[i].flags);
2508                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
2509                         /* Note that this cannot happen on a
2510                          * replacement device.  We just fail those on
2511                          * any error
2512                          */
2513                         pr_info_ratelimited(
2514                                 "md/raid:%s: read error corrected (%lu sectors at %llu on %s)\n",
2515                                 mdname(conf->mddev), STRIPE_SECTORS,
2516                                 (unsigned long long)s,
2517                                 bdevname(rdev->bdev, b));
2518                         atomic_add(STRIPE_SECTORS, &rdev->corrected_errors);
2519                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2520                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2521                 } else if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2522                         clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2523
2524                 if (test_bit(R5_InJournal, &sh->dev[i].flags))
2525                         /*
2526                          * end read for a page in journal, this
2527                          * must be preparing for prexor in rmw
2528                          */
2529                         set_bit(R5_OrigPageUPTDODATE, &sh->dev[i].flags);
2530
2531                 if (atomic_read(&rdev->read_errors))
2532                         atomic_set(&rdev->read_errors, 0);
2533         } else {
2534                 const char *bdn = bdevname(rdev->bdev, b);
2535                 int retry = 0;
2536                 int set_bad = 0;
2537
2538                 clear_bit(R5_UPTODATE, &sh->dev[i].flags);
2539                 atomic_inc(&rdev->read_errors);
2540                 if (test_bit(R5_ReadRepl, &sh->dev[i].flags))
2541                         pr_warn_ratelimited(
2542                                 "md/raid:%s: read error on replacement device (sector %llu on %s).\n",
2543                                 mdname(conf->mddev),
2544                                 (unsigned long long)s,
2545                                 bdn);
2546                 else if (conf->mddev->degraded >= conf->max_degraded) {
2547                         set_bad = 1;
2548                         pr_warn_ratelimited(
2549                                 "md/raid:%s: read error not correctable (sector %llu on %s).\n",
2550                                 mdname(conf->mddev),
2551                                 (unsigned long long)s,
2552                                 bdn);
2553                 } else if (test_bit(R5_ReWrite, &sh->dev[i].flags)) {
2554                         /* Oh, no!!! */
2555                         set_bad = 1;
2556                         pr_warn_ratelimited(
2557                                 "md/raid:%s: read error NOT corrected!! (sector %llu on %s).\n",
2558                                 mdname(conf->mddev),
2559                                 (unsigned long long)s,
2560                                 bdn);
2561                 } else if (atomic_read(&rdev->read_errors)
2562                          > conf->max_nr_stripes)
2563                         pr_warn("md/raid:%s: Too many read errors, failing device %s.\n",
2564                                mdname(conf->mddev), bdn);
2565                 else
2566                         retry = 1;
2567                 if (set_bad && test_bit(In_sync, &rdev->flags)
2568                     && !test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
2569                         retry = 1;
2570                 if (retry)
2571                         if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags)) {
2572                                 set_bit(R5_ReadError, &sh->dev[i].flags);
2573                                 clear_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2574                         } else
2575                                 set_bit(R5_ReadNoMerge, &sh->dev[i].flags);
2576                 else {
2577                         clear_bit(R5_ReadError, &sh->dev[i].flags);
2578                         clear_bit(R5_ReWrite, &sh->dev[i].flags);
2579                         if (!(set_bad
2580                               && test_bit(In_sync, &rdev->flags)
2581                               && rdev_set_badblocks(
2582                                       rdev, sh->sector, STRIPE_SECTORS, 0)))
2583                                 md_error(conf->mddev, rdev);
2584                 }
2585         }
2586         rdev_dec_pending(rdev, conf->mddev);
2587         bio_reset(bi);
2588         clear_bit(R5_LOCKED, &sh->dev[i].flags);
2589         set_bit(STRIPE_HANDLE, &sh->state);
2590         raid5_release_stripe(sh);
2591 }
2592
2593 static void raid5_end_write_request(struct bio *bi)
2594 {
2595         struct stripe_head *sh = bi->bi_private;
2596         struct r5conf *conf = sh->raid_conf;
2597         int disks = sh->disks, i;
2598         struct md_rdev *uninitialized_var(rdev);
2599         sector_t first_bad;
2600         int bad_sectors;
2601         int replacement = 0;
2602
2603         for (i = 0 ; i < disks; i++) {
2604                 if (bi == &sh->dev[i].req) {
2605                         rdev = conf->disks[i].rdev;
2606                         break;
2607                 }
2608                 if (bi == &sh->dev[i].rreq) {
2609                         rdev = conf->disks[i].replacement;
2610                         if (rdev)
2611                                 replacement = 1;
2612                         else
2613                                 /* rdev was removed and 'replacement'
2614                                  * replaced it.  rdev is not removed
2615                                  * until all requests are finished.
2616                                  */
2617                                 rdev = conf->disks[i].rdev;
2618                         break;
2619                 }
2620         }
2621         pr_debug("end_write_request %llu/%d, count %d, error: %d.\n",
2622                 (unsigned long long)sh->sector, i, atomic_read(&sh->count),
2623                 bi->bi_status);
2624         if (i == disks) {
2625                 bio_reset(bi);
2626                 BUG();
2627                 return;
2628         }
2629
2630         if (replacement) {
2631                 if (bi->bi_status)
2632                         md_error(conf->mddev, rdev);
2633                 else if (is_badblock(rdev, sh->sector,
2634                                      STRIPE_SECTORS,
2635                                      &first_bad, &bad_sectors))
2636                         set_bit(R5_MadeGoodRepl, &sh->dev[i].flags);
2637         } else {
2638                 if (bi->bi_status) {
2639                         set_bit(STRIPE_DEGRADED, &sh->state);
2640                         set_bit(WriteErrorSeen, &rdev->flags);
2641                         set_bit(R5_WriteError, &sh->dev[i].flags);
2642                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
2643                                 set_bit(MD_RECOVERY_NEEDED,
2644                                         &rdev->mddev->recovery);
2645                 } else if (is_badblock(rdev, sh->sector,
2646                                        STRIPE_SECTORS,
2647                                        &first_bad, &bad_sectors)) {
2648                         set_bit(R5_MadeGood, &sh->dev[i].flags);
2649                         if (test_bit(R5_ReadError, &sh->dev[i].flags))
2650                                 /* That was a successful write so make
2651                                  * sure it looks like we already did
2652                                  * a re-write.
2653                                  */
2654                                 set_bit(R5_ReWrite, &sh->dev[i].flags);
2655                 }
2656         }
2657         rdev_dec_pending(rdev, conf->mddev);
2658
2659         if (sh->batch_head && bi->bi_status && !replacement)
2660                 set_bit(STRIPE_BATCH_ERR, &sh->batch_head->state);
2661
2662         bio_reset(bi);
2663         if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags))
2664                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
2665         set_bit(STRIPE_HANDLE, &sh->state);
2666         raid5_release_stripe(sh);
2667
2668         if (sh->batch_head && sh != sh->batch_head)
2669                 raid5_release_stripe(sh->batch_head);
2670 }
2671
2672 static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
2673 {
2674         char b[BDEVNAME_SIZE];
2675         struct r5conf *conf = mddev->private;
2676         unsigned long flags;
2677         pr_debug("raid456: error called\n");
2678
2679         spin_lock_irqsave(&conf->device_lock, flags);
2680         set_bit(Faulty, &rdev->flags);
2681         clear_bit(In_sync, &rdev->flags);
2682         mddev->degraded = raid5_calc_degraded(conf);
2683         spin_unlock_irqrestore(&conf->device_lock, flags);
2684         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
2685
2686         set_bit(Blocked, &rdev->flags);
2687         set_mask_bits(&mddev->sb_flags, 0,
2688                       BIT(MD_SB_CHANGE_DEVS) | BIT(MD_SB_CHANGE_PENDING));
2689         pr_crit("md/raid:%s: Disk failure on %s, disabling device.\n"
2690                 "md/raid:%s: Operation continuing on %d devices.\n",
2691                 mdname(mddev),
2692                 bdevname(rdev->bdev, b),
2693                 mdname(mddev),
2694                 conf->raid_disks - mddev->degraded);
2695         r5c_update_on_rdev_error(mddev, rdev);
2696 }
2697
2698 /*
2699  * Input: a 'big' sector number,
2700  * Output: index of the data and parity disk, and the sector # in them.
2701  */
2702 sector_t raid5_compute_sector(struct r5conf *conf, sector_t r_sector,
2703                               int previous, int *dd_idx,
2704                               struct stripe_head *sh)
2705 {
2706         sector_t stripe, stripe2;
2707         sector_t chunk_number;
2708         unsigned int chunk_offset;
2709         int pd_idx, qd_idx;
2710         int ddf_layout = 0;
2711         sector_t new_sector;
2712         int algorithm = previous ? conf->prev_algo
2713                                  : conf->algorithm;
2714         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2715                                          : conf->chunk_sectors;
2716         int raid_disks = previous ? conf->previous_raid_disks
2717                                   : conf->raid_disks;
2718         int data_disks = raid_disks - conf->max_degraded;
2719
2720         /* First compute the information on this sector */
2721
2722         /*
2723          * Compute the chunk number and the sector offset inside the chunk
2724          */
2725         chunk_offset = sector_div(r_sector, sectors_per_chunk);
2726         chunk_number = r_sector;
2727
2728         /*
2729          * Compute the stripe number
2730          */
2731         stripe = chunk_number;
2732         *dd_idx = sector_div(stripe, data_disks);
2733         stripe2 = stripe;
2734         /*
2735          * Select the parity disk based on the user selected algorithm.
2736          */
2737         pd_idx = qd_idx = -1;
2738         switch(conf->level) {
2739         case 4:
2740                 pd_idx = data_disks;
2741                 break;
2742         case 5:
2743                 switch (algorithm) {
2744                 case ALGORITHM_LEFT_ASYMMETRIC:
2745                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2746                         if (*dd_idx >= pd_idx)
2747                                 (*dd_idx)++;
2748                         break;
2749                 case ALGORITHM_RIGHT_ASYMMETRIC:
2750                         pd_idx = sector_div(stripe2, raid_disks);
2751                         if (*dd_idx >= pd_idx)
2752                                 (*dd_idx)++;
2753                         break;
2754                 case ALGORITHM_LEFT_SYMMETRIC:
2755                         pd_idx = data_disks - sector_div(stripe2, raid_disks);
2756                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2757                         break;
2758                 case ALGORITHM_RIGHT_SYMMETRIC:
2759                         pd_idx = sector_div(stripe2, raid_disks);
2760                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2761                         break;
2762                 case ALGORITHM_PARITY_0:
2763                         pd_idx = 0;
2764                         (*dd_idx)++;
2765                         break;
2766                 case ALGORITHM_PARITY_N:
2767                         pd_idx = data_disks;
2768                         break;
2769                 default:
2770                         BUG();
2771                 }
2772                 break;
2773         case 6:
2774
2775                 switch (algorithm) {
2776                 case ALGORITHM_LEFT_ASYMMETRIC:
2777                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2778                         qd_idx = pd_idx + 1;
2779                         if (pd_idx == raid_disks-1) {
2780                                 (*dd_idx)++;    /* Q D D D P */
2781                                 qd_idx = 0;
2782                         } else if (*dd_idx >= pd_idx)
2783                                 (*dd_idx) += 2; /* D D P Q D */
2784                         break;
2785                 case ALGORITHM_RIGHT_ASYMMETRIC:
2786                         pd_idx = sector_div(stripe2, raid_disks);
2787                         qd_idx = pd_idx + 1;
2788                         if (pd_idx == raid_disks-1) {
2789                                 (*dd_idx)++;    /* Q D D D P */
2790                                 qd_idx = 0;
2791                         } else if (*dd_idx >= pd_idx)
2792                                 (*dd_idx) += 2; /* D D P Q D */
2793                         break;
2794                 case ALGORITHM_LEFT_SYMMETRIC:
2795                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2796                         qd_idx = (pd_idx + 1) % raid_disks;
2797                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2798                         break;
2799                 case ALGORITHM_RIGHT_SYMMETRIC:
2800                         pd_idx = sector_div(stripe2, raid_disks);
2801                         qd_idx = (pd_idx + 1) % raid_disks;
2802                         *dd_idx = (pd_idx + 2 + *dd_idx) % raid_disks;
2803                         break;
2804
2805                 case ALGORITHM_PARITY_0:
2806                         pd_idx = 0;
2807                         qd_idx = 1;
2808                         (*dd_idx) += 2;
2809                         break;
2810                 case ALGORITHM_PARITY_N:
2811                         pd_idx = data_disks;
2812                         qd_idx = data_disks + 1;
2813                         break;
2814
2815                 case ALGORITHM_ROTATING_ZERO_RESTART:
2816                         /* Exactly the same as RIGHT_ASYMMETRIC, but or
2817                          * of blocks for computing Q is different.
2818                          */
2819                         pd_idx = sector_div(stripe2, raid_disks);
2820                         qd_idx = pd_idx + 1;
2821                         if (pd_idx == raid_disks-1) {
2822                                 (*dd_idx)++;    /* Q D D D P */
2823                                 qd_idx = 0;
2824                         } else if (*dd_idx >= pd_idx)
2825                                 (*dd_idx) += 2; /* D D P Q D */
2826                         ddf_layout = 1;
2827                         break;
2828
2829                 case ALGORITHM_ROTATING_N_RESTART:
2830                         /* Same a left_asymmetric, by first stripe is
2831                          * D D D P Q  rather than
2832                          * Q D D D P
2833                          */
2834                         stripe2 += 1;
2835                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2836                         qd_idx = pd_idx + 1;
2837                         if (pd_idx == raid_disks-1) {
2838                                 (*dd_idx)++;    /* Q D D D P */
2839                                 qd_idx = 0;
2840                         } else if (*dd_idx >= pd_idx)
2841                                 (*dd_idx) += 2; /* D D P Q D */
2842                         ddf_layout = 1;
2843                         break;
2844
2845                 case ALGORITHM_ROTATING_N_CONTINUE:
2846                         /* Same as left_symmetric but Q is before P */
2847                         pd_idx = raid_disks - 1 - sector_div(stripe2, raid_disks);
2848                         qd_idx = (pd_idx + raid_disks - 1) % raid_disks;
2849                         *dd_idx = (pd_idx + 1 + *dd_idx) % raid_disks;
2850                         ddf_layout = 1;
2851                         break;
2852
2853                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2854                         /* RAID5 left_asymmetric, with Q on last device */
2855                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2856                         if (*dd_idx >= pd_idx)
2857                                 (*dd_idx)++;
2858                         qd_idx = raid_disks - 1;
2859                         break;
2860
2861                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2862                         pd_idx = sector_div(stripe2, raid_disks-1);
2863                         if (*dd_idx >= pd_idx)
2864                                 (*dd_idx)++;
2865                         qd_idx = raid_disks - 1;
2866                         break;
2867
2868                 case ALGORITHM_LEFT_SYMMETRIC_6:
2869                         pd_idx = data_disks - sector_div(stripe2, raid_disks-1);
2870                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2871                         qd_idx = raid_disks - 1;
2872                         break;
2873
2874                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2875                         pd_idx = sector_div(stripe2, raid_disks-1);
2876                         *dd_idx = (pd_idx + 1 + *dd_idx) % (raid_disks-1);
2877                         qd_idx = raid_disks - 1;
2878                         break;
2879
2880                 case ALGORITHM_PARITY_0_6:
2881                         pd_idx = 0;
2882                         (*dd_idx)++;
2883                         qd_idx = raid_disks - 1;
2884                         break;
2885
2886                 default:
2887                         BUG();
2888                 }
2889                 break;
2890         }
2891
2892         if (sh) {
2893                 sh->pd_idx = pd_idx;
2894                 sh->qd_idx = qd_idx;
2895                 sh->ddf_layout = ddf_layout;
2896         }
2897         /*
2898          * Finally, compute the new sector number
2899          */
2900         new_sector = (sector_t)stripe * sectors_per_chunk + chunk_offset;
2901         return new_sector;
2902 }
2903
2904 sector_t raid5_compute_blocknr(struct stripe_head *sh, int i, int previous)
2905 {
2906         struct r5conf *conf = sh->raid_conf;
2907         int raid_disks = sh->disks;
2908         int data_disks = raid_disks - conf->max_degraded;
2909         sector_t new_sector = sh->sector, check;
2910         int sectors_per_chunk = previous ? conf->prev_chunk_sectors
2911                                          : conf->chunk_sectors;
2912         int algorithm = previous ? conf->prev_algo
2913                                  : conf->algorithm;
2914         sector_t stripe;
2915         int chunk_offset;
2916         sector_t chunk_number;
2917         int dummy1, dd_idx = i;
2918         sector_t r_sector;
2919         struct stripe_head sh2;
2920
2921         chunk_offset = sector_div(new_sector, sectors_per_chunk);
2922         stripe = new_sector;
2923
2924         if (i == sh->pd_idx)
2925                 return 0;
2926         switch(conf->level) {
2927         case 4: break;
2928         case 5:
2929                 switch (algorithm) {
2930                 case ALGORITHM_LEFT_ASYMMETRIC:
2931                 case ALGORITHM_RIGHT_ASYMMETRIC:
2932                         if (i > sh->pd_idx)
2933                                 i--;
2934                         break;
2935                 case ALGORITHM_LEFT_SYMMETRIC:
2936                 case ALGORITHM_RIGHT_SYMMETRIC:
2937                         if (i < sh->pd_idx)
2938                                 i += raid_disks;
2939                         i -= (sh->pd_idx + 1);
2940                         break;
2941                 case ALGORITHM_PARITY_0:
2942                         i -= 1;
2943                         break;
2944                 case ALGORITHM_PARITY_N:
2945                         break;
2946                 default:
2947                         BUG();
2948                 }
2949                 break;
2950         case 6:
2951                 if (i == sh->qd_idx)
2952                         return 0; /* It is the Q disk */
2953                 switch (algorithm) {
2954                 case ALGORITHM_LEFT_ASYMMETRIC:
2955                 case ALGORITHM_RIGHT_ASYMMETRIC:
2956                 case ALGORITHM_ROTATING_ZERO_RESTART:
2957                 case ALGORITHM_ROTATING_N_RESTART:
2958                         if (sh->pd_idx == raid_disks-1)
2959                                 i--;    /* Q D D D P */
2960                         else if (i > sh->pd_idx)
2961                                 i -= 2; /* D D P Q D */
2962                         break;
2963                 case ALGORITHM_LEFT_SYMMETRIC:
2964                 case ALGORITHM_RIGHT_SYMMETRIC:
2965                         if (sh->pd_idx == raid_disks-1)
2966                                 i--; /* Q D D D P */
2967                         else {
2968                                 /* D D P Q D */
2969                                 if (i < sh->pd_idx)
2970                                         i += raid_disks;
2971                                 i -= (sh->pd_idx + 2);
2972                         }
2973                         break;
2974                 case ALGORITHM_PARITY_0:
2975                         i -= 2;
2976                         break;
2977                 case ALGORITHM_PARITY_N:
2978                         break;
2979                 case ALGORITHM_ROTATING_N_CONTINUE:
2980                         /* Like left_symmetric, but P is before Q */
2981                         if (sh->pd_idx == 0)
2982                                 i--;    /* P D D D Q */
2983                         else {
2984                                 /* D D Q P D */
2985                                 if (i < sh->pd_idx)
2986                                         i += raid_disks;
2987                                 i -= (sh->pd_idx + 1);
2988                         }
2989                         break;
2990                 case ALGORITHM_LEFT_ASYMMETRIC_6:
2991                 case ALGORITHM_RIGHT_ASYMMETRIC_6:
2992                         if (i > sh->pd_idx)
2993                                 i--;
2994                         break;
2995                 case ALGORITHM_LEFT_SYMMETRIC_6:
2996                 case ALGORITHM_RIGHT_SYMMETRIC_6:
2997                         if (i < sh->pd_idx)
2998                                 i += data_disks + 1;
2999                         i -= (sh->pd_idx + 1);
3000                         break;
3001                 case ALGORITHM_PARITY_0_6:
3002                         i -= 1;
3003                         break;
3004                 default:
3005                         BUG();
3006                 }
3007                 break;
3008         }
3009
3010         chunk_number = stripe * data_disks + i;
3011         r_sector = chunk_number * sectors_per_chunk + chunk_offset;
3012
3013         check = raid5_compute_sector(conf, r_sector,
3014                                      previous, &dummy1, &sh2);
3015         if (check != sh->sector || dummy1 != dd_idx || sh2.pd_idx != sh->pd_idx
3016                 || sh2.qd_idx != sh->qd_idx) {
3017                 pr_warn("md/raid:%s: compute_blocknr: map not correct\n",
3018                         mdname(conf->mddev));
3019                 return 0;
3020         }
3021         return r_sector;
3022 }
3023
3024 /*
3025  * There are cases where we want handle_stripe_dirtying() and
3026  * schedule_reconstruction() to delay towrite to some dev of a stripe.
3027  *
3028  * This function checks whether we want to delay the towrite. Specifically,
3029  * we delay the towrite when:
3030  *
3031  *   1. degraded stripe has a non-overwrite to the missing dev, AND this
3032  *      stripe has data in journal (for other devices).
3033  *
3034  *      In this case, when reading data for the non-overwrite dev, it is
3035  *      necessary to handle complex rmw of write back cache (prexor with
3036  *      orig_page, and xor with page). To keep read path simple, we would
3037  *      like to flush data in journal to RAID disks first, so complex rmw
3038  *      is handled in the write patch (handle_stripe_dirtying).
3039  *
3040  *   2. when journal space is critical (R5C_LOG_CRITICAL=1)
3041  *
3042  *      It is important to be able to flush all stripes in raid5-cache.
3043  *      Therefore, we need reserve some space on the journal device for
3044  *      these flushes. If flush operation includes pending writes to the
3045  *      stripe, we need to reserve (conf->raid_disk + 1) pages per stripe
3046  *      for the flush out. If we exclude these pending writes from flush
3047  *      operation, we only need (conf->max_degraded + 1) pages per stripe.
3048  *      Therefore, excluding pending writes in these cases enables more
3049  *      efficient use of the journal device.
3050  *
3051  *      Note: To make sure the stripe makes progress, we only delay
3052  *      towrite for stripes with data already in journal (injournal > 0).
3053  *      When LOG_CRITICAL, stripes with injournal == 0 will be sent to
3054  *      no_space_stripes list.
3055  *
3056  *   3. during journal failure
3057  *      In journal failure, we try to flush all cached data to raid disks
3058  *      based on data in stripe cache. The array is read-only to upper
3059  *      layers, so we would skip all pending writes.
3060  *
3061  */
3062 static inline bool delay_towrite(struct r5conf *conf,
3063                                  struct r5dev *dev,
3064                                  struct stripe_head_state *s)
3065 {
3066         /* case 1 above */
3067         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3068             !test_bit(R5_Insync, &dev->flags) && s->injournal)
3069                 return true;
3070         /* case 2 above */
3071         if (test_bit(R5C_LOG_CRITICAL, &conf->cache_state) &&
3072             s->injournal > 0)
3073                 return true;
3074         /* case 3 above */
3075         if (s->log_failed && s->injournal)
3076                 return true;
3077         return false;
3078 }
3079
3080 static void
3081 schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s,
3082                          int rcw, int expand)
3083 {
3084         int i, pd_idx = sh->pd_idx, qd_idx = sh->qd_idx, disks = sh->disks;
3085         struct r5conf *conf = sh->raid_conf;
3086         int level = conf->level;
3087
3088         if (rcw) {
3089                 /*
3090                  * In some cases, handle_stripe_dirtying initially decided to
3091                  * run rmw and allocates extra page for prexor. However, rcw is
3092                  * cheaper later on. We need to free the extra page now,
3093                  * because we won't be able to do that in ops_complete_prexor().
3094                  */
3095                 r5c_release_extra_page(sh);
3096
3097                 for (i = disks; i--; ) {
3098                         struct r5dev *dev = &sh->dev[i];
3099
3100                         if (dev->towrite && !delay_towrite(conf, dev, s)) {
3101                                 set_bit(R5_LOCKED, &dev->flags);
3102                                 set_bit(R5_Wantdrain, &dev->flags);
3103                                 if (!expand)
3104                                         clear_bit(R5_UPTODATE, &dev->flags);
3105                                 s->locked++;
3106                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3107                                 set_bit(R5_LOCKED, &dev->flags);
3108                                 s->locked++;
3109                         }
3110                 }
3111                 /* if we are not expanding this is a proper write request, and
3112                  * there will be bios with new data to be drained into the
3113                  * stripe cache
3114                  */
3115                 if (!expand) {
3116                         if (!s->locked)
3117                                 /* False alarm, nothing to do */
3118                                 return;
3119                         sh->reconstruct_state = reconstruct_state_drain_run;
3120                         set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3121                 } else
3122                         sh->reconstruct_state = reconstruct_state_run;
3123
3124                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3125
3126                 if (s->locked + conf->max_degraded == disks)
3127                         if (!test_and_set_bit(STRIPE_FULL_WRITE, &sh->state))
3128                                 atomic_inc(&conf->pending_full_writes);
3129         } else {
3130                 BUG_ON(!(test_bit(R5_UPTODATE, &sh->dev[pd_idx].flags) ||
3131                         test_bit(R5_Wantcompute, &sh->dev[pd_idx].flags)));
3132                 BUG_ON(level == 6 &&
3133                         (!(test_bit(R5_UPTODATE, &sh->dev[qd_idx].flags) ||
3134                            test_bit(R5_Wantcompute, &sh->dev[qd_idx].flags))));
3135
3136                 for (i = disks; i--; ) {
3137                         struct r5dev *dev = &sh->dev[i];
3138                         if (i == pd_idx || i == qd_idx)
3139                                 continue;
3140
3141                         if (dev->towrite &&
3142                             (test_bit(R5_UPTODATE, &dev->flags) ||
3143                              test_bit(R5_Wantcompute, &dev->flags))) {
3144                                 set_bit(R5_Wantdrain, &dev->flags);
3145                                 set_bit(R5_LOCKED, &dev->flags);
3146                                 clear_bit(R5_UPTODATE, &dev->flags);
3147                                 s->locked++;
3148                         } else if (test_bit(R5_InJournal, &dev->flags)) {
3149                                 set_bit(R5_LOCKED, &dev->flags);
3150                                 s->locked++;
3151                         }
3152                 }
3153                 if (!s->locked)
3154                         /* False alarm - nothing to do */
3155                         return;
3156                 sh->reconstruct_state = reconstruct_state_prexor_drain_run;
3157                 set_bit(STRIPE_OP_PREXOR, &s->ops_request);
3158                 set_bit(STRIPE_OP_BIODRAIN, &s->ops_request);
3159                 set_bit(STRIPE_OP_RECONSTRUCT, &s->ops_request);
3160         }
3161
3162         /* keep the parity disk(s) locked while asynchronous operations
3163          * are in flight
3164          */
3165         set_bit(R5_LOCKED, &sh->dev[pd_idx].flags);
3166         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
3167         s->locked++;
3168
3169         if (level == 6) {
3170                 int qd_idx = sh->qd_idx;
3171                 struct r5dev *dev = &sh->dev[qd_idx];
3172
3173                 set_bit(R5_LOCKED, &dev->flags);
3174                 clear_bit(R5_UPTODATE, &dev->flags);
3175                 s->locked++;
3176         }
3177
3178         if (raid5_has_ppl(sh->raid_conf) && sh->ppl_page &&
3179             test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) &&
3180             !test_bit(STRIPE_FULL_WRITE, &sh->state) &&
3181             test_bit(R5_Insync, &sh->dev[pd_idx].flags))
3182                 set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request);
3183
3184         pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n",
3185                 __func__, (unsigned long long)sh->sector,
3186                 s->locked, s->ops_request);
3187 }
3188
3189 /*
3190  * Each stripe/dev can have one or more bion attached.
3191  * toread/towrite point to the first in a chain.
3192  * The bi_next chain must be in order.
3193  */
3194 static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx,
3195                           int forwrite, int previous)
3196 {
3197         struct bio **bip;
3198         struct r5conf *conf = sh->raid_conf;
3199         int firstwrite=0;
3200
3201         pr_debug("adding bi b#%llu to stripe s#%llu\n",
3202                 (unsigned long long)bi->bi_iter.bi_sector,
3203                 (unsigned long long)sh->sector);
3204
3205         spin_lock_irq(&sh->stripe_lock);
3206         /* Don't allow new IO added to stripes in batch list */
3207         if (sh->batch_head)
3208                 goto overlap;
3209         if (forwrite) {
3210                 bip = &sh->dev[dd_idx].towrite;
3211                 if (*bip == NULL)
3212                         firstwrite = 1;
3213         } else
3214                 bip = &sh->dev[dd_idx].toread;
3215         while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) {
3216                 if (bio_end_sector(*bip) > bi->bi_iter.bi_sector)
3217                         goto overlap;
3218                 bip = & (*bip)->bi_next;
3219         }
3220         if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi))
3221                 goto overlap;
3222
3223         if (forwrite && raid5_has_ppl(conf)) {
3224                 /*
3225                  * With PPL only writes to consecutive data chunks within a
3226                  * stripe are allowed because for a single stripe_head we can
3227                  * only have one PPL entry at a time, which describes one data
3228                  * range. Not really an overlap, but wait_for_overlap can be
3229                  * used to handle this.
3230                  */
3231                 sector_t sector;
3232                 sector_t first = 0;
3233                 sector_t last = 0;
3234                 int count = 0;
3235                 int i;
3236
3237                 for (i = 0; i < sh->disks; i++) {
3238                         if (i != sh->pd_idx &&
3239                             (i == dd_idx || sh->dev[i].towrite)) {
3240                                 sector = sh->dev[i].sector;
3241                                 if (count == 0 || sector < first)
3242                                         first = sector;
3243                                 if (sector > last)
3244                                         last = sector;
3245                                 count++;
3246                         }
3247                 }
3248
3249                 if (first + conf->chunk_sectors * (count - 1) != last)
3250                         goto overlap;
3251         }
3252
3253         if (!forwrite || previous)
3254                 clear_bit(STRIPE_BATCH_READY, &sh->state);
3255
3256         BUG_ON(*bip && bi->bi_next && (*bip) != bi->bi_next);
3257         if (*bip)
3258                 bi->bi_next = *bip;
3259         *bip = bi;
3260         bio_inc_remaining(bi);
3261         md_write_inc(conf->mddev, bi);
3262
3263         if (forwrite) {
3264                 /* check if page is covered */
3265                 sector_t sector = sh->dev[dd_idx].sector;
3266                 for (bi=sh->dev[dd_idx].towrite;
3267                      sector < sh->dev[dd_idx].sector + STRIPE_SECTORS &&
3268                              bi && bi->bi_iter.bi_sector <= sector;
3269                      bi = r5_next_bio(bi, sh->dev[dd_idx].sector)) {
3270                         if (bio_end_sector(bi) >= sector)
3271                                 sector = bio_end_sector(bi);
3272                 }
3273                 if (sector >= sh->dev[dd_idx].sector + STRIPE_SECTORS)
3274                         if (!test_and_set_bit(R5_OVERWRITE, &sh->dev[dd_idx].flags))
3275                                 sh->overwrite_disks++;
3276         }
3277
3278         pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
3279                 (unsigned long long)(*bip)->bi_iter.bi_sector,
3280                 (unsigned long long)sh->sector, dd_idx);
3281
3282         if (conf->mddev->bitmap && firstwrite) {
3283                 /* Cannot hold spinlock over bitmap_startwrite,
3284                  * but must ensure this isn't added to a batch until
3285                  * we have added to the bitmap and set bm_seq.
3286                  * So set STRIPE_BITMAP_PENDING to prevent
3287                  * batching.
3288                  * If multiple add_stripe_bio() calls race here they
3289                  * much all set STRIPE_BITMAP_PENDING.  So only the first one
3290                  * to complete "bitmap_startwrite" gets to set
3291                  * STRIPE_BIT_DELAY.  This is important as once a stripe
3292                  * is added to a batch, STRIPE_BIT_DELAY cannot be changed
3293                  * any more.
3294                  */
3295                 set_bit(STRIPE_BITMAP_PENDING, &sh->state);
3296                 spin_unlock_irq(&sh->stripe_lock);
3297                 bitmap_startwrite(conf->mddev->bitmap, sh->sector,
3298                                   STRIPE_SECTORS, 0);
3299                 spin_lock_irq(&sh->stripe_lock);
3300                 clear_bit(STRIPE_BITMAP_PENDING, &sh->state);
3301                 if (!sh->batch_head) {
3302                         sh->bm_seq = conf->seq_flush+1;
3303                         set_bit(STRIPE_BIT_DELAY, &sh->state);
3304                 }
3305         }
3306         spin_unlock_irq(&sh->stripe_lock);
3307
3308         if (stripe_can_batch(sh))
3309                 stripe_add_to_batch_list(conf, sh);
3310         return 1;
3311
3312  overlap:
3313         set_bit(R5_Overlap, &sh->dev[dd_idx].flags);
3314         spin_unlock_irq(&sh->stripe_lock);
3315         return 0;
3316 }
3317
3318 static void end_reshape(struct r5conf *conf);
3319
3320 static void stripe_set_idx(sector_t stripe, struct r5conf *conf, int previous,
3321                             struct stripe_head *sh)
3322 {
3323         int sectors_per_chunk =
3324                 previous ? conf->prev_chunk_sectors : conf->chunk_sectors;
3325         int dd_idx;
3326         int chunk_offset = sector_div(stripe, sectors_per_chunk);
3327         int disks = previous ? conf->previous_raid_disks : conf->raid_disks;
3328
3329         raid5_compute_sector(conf,
3330                              stripe * (disks - conf->max_degraded)
3331                              *sectors_per_chunk + chunk_offset,
3332                              previous,
3333                              &dd_idx, sh);
3334 }
3335
3336 static void
3337 handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh,
3338                      struct stripe_head_state *s, int disks)
3339 {
3340         int i;
3341         BUG_ON(sh->batch_head);
3342         for (i = disks; i--; ) {
3343                 struct bio *bi;
3344                 int bitmap_end = 0;
3345
3346                 if (test_bit(R5_ReadError, &sh->dev[i].flags)) {
3347                         struct md_rdev *rdev;
3348                         rcu_read_lock();
3349                         rdev = rcu_dereference(conf->disks[i].rdev);
3350                         if (rdev && test_bit(In_sync, &rdev->flags) &&
3351                             !test_bit(Faulty, &rdev->flags))
3352                                 atomic_inc(&rdev->nr_pending);
3353                         else
3354                                 rdev = NULL;
3355                         rcu_read_unlock();
3356                         if (rdev) {
3357                                 if (!rdev_set_badblocks(
3358                                             rdev,
3359                                             sh->sector,
3360                                             STRIPE_SECTORS, 0))
3361                                         md_error(conf->mddev, rdev);
3362                                 rdev_dec_pending(rdev, conf->mddev);
3363                         }
3364                 }
3365                 spin_lock_irq(&sh->stripe_lock);
3366                 /* fail all writes first */
3367                 bi = sh->dev[i].towrite;
3368                 sh->dev[i].towrite = NULL;
3369                 sh->overwrite_disks = 0;
3370                 spin_unlock_irq(&sh->stripe_lock);
3371                 if (bi)
3372                         bitmap_end = 1;
3373
3374                 log_stripe_write_finished(sh);
3375
3376                 if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3377                         wake_up(&conf->wait_for_overlap);
3378
3379                 while (bi && bi->bi_iter.bi_sector <
3380                         sh->dev[i].sector + STRIPE_SECTORS) {
3381                         struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector);
3382
3383                         md_write_end(conf->mddev);
3384                         bio_io_error(bi);
3385                         bi = nextbi;
3386                 }
3387                 if (bitmap_end)
3388                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3389                                 STRIPE_SECTORS, 0, 0);
3390                 bitmap_end = 0;
3391                 /* and fail all 'written' */
3392                 bi = sh->dev[i].written;
3393                 sh->dev[i].written = NULL;
3394                 if (test_and_clear_bit(R5_SkipCopy, &sh->dev[i].flags)) {
3395                         WARN_ON(test_bit(R5_UPTODATE, &sh->dev[i].flags));
3396                         sh->dev[i].page = sh->dev[i].orig_page;
3397                 }
3398
3399                 if (bi) bitmap_end = 1;
3400                 while (bi && bi->bi_iter.bi_sector <
3401                        sh->dev[i].sector + STRIPE_SECTORS) {
3402                         struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector);
3403
3404                         md_write_end(conf->mddev);
3405                         bio_io_error(bi);
3406                         bi = bi2;
3407                 }
3408
3409                 /* fail any reads if this device is non-operational and
3410                  * the data has not reached the cache yet.
3411                  */
3412                 if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
3413                     s->failed > conf->max_degraded &&
3414                     (!test_bit(R5_Insync, &sh->dev[i].flags) ||
3415                       test_bit(R5_ReadError, &sh->dev[i].flags))) {
3416                         spin_lock_irq(&sh->stripe_lock);
3417                         bi = sh->dev[i].toread;
3418                         sh->dev[i].toread = NULL;
3419                         spin_unlock_irq(&sh->stripe_lock);
3420                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
3421                                 wake_up(&conf->wait_for_overlap);
3422                         if (bi)
3423                                 s->to_read--;
3424                         while (bi && bi->bi_iter.bi_sector <
3425                                sh->dev[i].sector + STRIPE_SECTORS) {
3426                                 struct bio *nextbi =
3427                                         r5_next_bio(bi, sh->dev[i].sector);
3428
3429                                 bio_io_error(bi);
3430                                 bi = nextbi;
3431                         }
3432                 }
3433                 if (bitmap_end)
3434                         bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3435                                         STRIPE_SECTORS, 0, 0);
3436                 /* If we were in the middle of a write the parity block might
3437                  * still be locked - so just clear all R5_LOCKED flags
3438                  */
3439                 clear_bit(R5_LOCKED, &sh->dev[i].flags);
3440         }
3441         s->to_write = 0;
3442         s->written = 0;
3443
3444         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3445                 if (atomic_dec_and_test(&conf->pending_full_writes))
3446                         md_wakeup_thread(conf->mddev->thread);
3447 }
3448
3449 static void
3450 handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
3451                    struct stripe_head_state *s)
3452 {
3453         int abort = 0;
3454         int i;
3455
3456         BUG_ON(sh->batch_head);
3457         clear_bit(STRIPE_SYNCING, &sh->state);
3458         if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
3459                 wake_up(&conf->wait_for_overlap);
3460         s->syncing = 0;
3461         s->replacing = 0;
3462         /* There is nothing more to do for sync/check/repair.
3463          * Don't even need to abort as that is handled elsewhere
3464          * if needed, and not always wanted e.g. if there is a known
3465          * bad block here.
3466          * For recover/replace we need to record a bad block on all
3467          * non-sync devices, or abort the recovery
3468          */
3469         if (test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery)) {
3470                 /* During recovery devices cannot be removed, so
3471                  * locking and refcounting of rdevs is not needed
3472                  */
3473                 rcu_read_lock();
3474                 for (i = 0; i < conf->raid_disks; i++) {
3475                         struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
3476                         if (rdev
3477                             && !test_bit(Faulty, &rdev->flags)
3478                             && !test_bit(In_sync, &rdev->flags)
3479                             && !rdev_set_badblocks(rdev, sh->sector,
3480                                                    STRIPE_SECTORS, 0))
3481                                 abort = 1;
3482                         rdev = rcu_dereference(conf->disks[i].replacement);
3483                         if (rdev
3484                             && !test_bit(Faulty, &rdev->flags)
3485                             && !test_bit(In_sync, &rdev->flags)
3486                             && !rdev_set_badblocks(rdev, sh->sector,
3487                                                    STRIPE_SECTORS, 0))
3488                                 abort = 1;
3489                 }
3490                 rcu_read_unlock();
3491                 if (abort)
3492                         conf->recovery_disabled =
3493                                 conf->mddev->recovery_disabled;
3494         }
3495         md_done_sync(conf->mddev, STRIPE_SECTORS, !abort);
3496 }
3497
3498 static int want_replace(struct stripe_head *sh, int disk_idx)
3499 {
3500         struct md_rdev *rdev;
3501         int rv = 0;
3502
3503         rcu_read_lock();
3504         rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement);
3505         if (rdev
3506             && !test_bit(Faulty, &rdev->flags)
3507             && !test_bit(In_sync, &rdev->flags)
3508             && (rdev->recovery_offset <= sh->sector
3509                 || rdev->mddev->recovery_cp <= sh->sector))
3510                 rv = 1;
3511         rcu_read_unlock();
3512         return rv;
3513 }
3514
3515 static int need_this_block(struct stripe_head *sh, struct stripe_head_state *s,
3516                            int disk_idx, int disks)
3517 {
3518         struct r5dev *dev = &sh->dev[disk_idx];
3519         struct r5dev *fdev[2] = { &sh->dev[s->failed_num[0]],
3520                                   &sh->dev[s->failed_num[1]] };
3521         int i;
3522
3523
3524         if (test_bit(R5_LOCKED, &dev->flags) ||
3525             test_bit(R5_UPTODATE, &dev->flags))
3526                 /* No point reading this as we already have it or have
3527                  * decided to get it.
3528                  */
3529                 return 0;
3530
3531         if (dev->toread ||
3532             (dev->towrite && !test_bit(R5_OVERWRITE, &dev->flags)))
3533                 /* We need this block to directly satisfy a request */
3534                 return 1;
3535
3536         if (s->syncing || s->expanding ||
3537             (s->replacing && want_replace(sh, disk_idx)))
3538                 /* When syncing, or expanding we read everything.
3539                  * When replacing, we need the replaced block.
3540                  */
3541                 return 1;
3542
3543         if ((s->failed >= 1 && fdev[0]->toread) ||
3544             (s->failed >= 2 && fdev[1]->toread))
3545                 /* If we want to read from a failed device, then
3546                  * we need to actually read every other device.
3547                  */
3548                 return 1;
3549
3550         /* Sometimes neither read-modify-write nor reconstruct-write
3551          * cycles can work.  In those cases we read every block we
3552          * can.  Then the parity-update is certain to have enough to
3553          * work with.
3554          * This can only be a problem when we need to write something,
3555          * and some device has failed.  If either of those tests
3556          * fail we need look no further.
3557          */
3558         if (!s->failed || !s->to_write)
3559                 return 0;
3560
3561         if (test_bit(R5_Insync, &dev->flags) &&
3562             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
3563                 /* Pre-reads at not permitted until after short delay
3564                  * to gather multiple requests.  However if this
3565                  * device is no Insync, the block could only be computed
3566                  * and there is no need to delay that.
3567                  */
3568                 return 0;
3569
3570         for (i = 0; i < s->failed && i < 2; i++) {
3571                 if (fdev[i]->towrite &&
3572                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3573                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3574                         /* If we have a partial write to a failed
3575                          * device, then we will need to reconstruct
3576                          * the content of that device, so all other
3577                          * devices must be read.
3578                          */
3579                         return 1;
3580         }
3581
3582         /* If we are forced to do a reconstruct-write, either because
3583          * the current RAID6 implementation only supports that, or
3584          * because parity cannot be trusted and we are currently
3585          * recovering it, there is extra need to be careful.
3586          * If one of the devices that we would need to read, because
3587          * it is not being overwritten (and maybe not written at all)
3588          * is missing/faulty, then we need to read everything we can.
3589          */
3590         if (sh->raid_conf->level != 6 &&
3591             sh->sector < sh->raid_conf->mddev->recovery_cp)
3592                 /* reconstruct-write isn't being forced */
3593                 return 0;
3594         for (i = 0; i < s->failed && i < 2; i++) {
3595                 if (s->failed_num[i] != sh->pd_idx &&
3596                     s->failed_num[i] != sh->qd_idx &&
3597                     !test_bit(R5_UPTODATE, &fdev[i]->flags) &&
3598                     !test_bit(R5_OVERWRITE, &fdev[i]->flags))
3599                         return 1;
3600         }
3601
3602         return 0;
3603 }
3604
3605 /* fetch_block - checks the given member device to see if its data needs
3606  * to be read or computed to satisfy a request.
3607  *
3608  * Returns 1 when no more member devices need to be checked, otherwise returns
3609  * 0 to tell the loop in handle_stripe_fill to continue
3610  */
3611 static int fetch_block(struct stripe_head *sh, struct stripe_head_state *s,
3612                        int disk_idx, int disks)
3613 {
3614         struct r5dev *dev = &sh->dev[disk_idx];
3615
3616         /* is the data in this block needed, and can we get it? */
3617         if (need_this_block(sh, s, disk_idx, disks)) {
3618                 /* we would like to get this block, possibly by computing it,
3619                  * otherwise read it if the backing disk is insync
3620                  */
3621                 BUG_ON(test_bit(R5_Wantcompute, &dev->flags));
3622                 BUG_ON(test_bit(R5_Wantread, &dev->flags));
3623                 BUG_ON(sh->batch_head);
3624
3625                 /*
3626                  * In the raid6 case if the only non-uptodate disk is P
3627                  * then we already trusted P to compute the other failed
3628                  * drives. It is safe to compute rather than re-read P.
3629                  * In other cases we only compute blocks from failed
3630                  * devices, otherwise check/repair might fail to detect
3631                  * a real inconsistency.
3632                  */
3633
3634                 if ((s->uptodate == disks - 1) &&
3635                     ((sh->qd_idx >= 0 && sh->pd_idx == disk_idx) ||
3636                     (s->failed && (disk_idx == s->failed_num[0] ||
3637                                    disk_idx == s->failed_num[1])))) {
3638                         /* have disk failed, and we're requested to fetch it;
3639                          * do compute it
3640                          */
3641                         pr_debug("Computing stripe %llu block %d\n",
3642                                (unsigned long long)sh->sector, disk_idx);
3643                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3644                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3645                         set_bit(R5_Wantcompute, &dev->flags);
3646                         sh->ops.target = disk_idx;
3647                         sh->ops.target2 = -1; /* no 2nd target */
3648                         s->req_compute = 1;
3649                         /* Careful: from this point on 'uptodate' is in the eye
3650                          * of raid_run_ops which services 'compute' operations
3651                          * before writes. R5_Wantcompute flags a block that will
3652                          * be R5_UPTODATE by the time it is needed for a
3653                          * subsequent operation.
3654                          */
3655                         s->uptodate++;
3656                         return 1;
3657                 } else if (s->uptodate == disks-2 && s->failed >= 2) {
3658                         /* Computing 2-failure is *very* expensive; only
3659                          * do it if failed >= 2
3660                          */
3661                         int other;
3662                         for (other = disks; other--; ) {
3663                                 if (other == disk_idx)
3664                                         continue;
3665                                 if (!test_bit(R5_UPTODATE,
3666                                       &sh->dev[other].flags))
3667                                         break;
3668                         }
3669                         BUG_ON(other < 0);
3670                         pr_debug("Computing stripe %llu blocks %d,%d\n",
3671                                (unsigned long long)sh->sector,
3672                                disk_idx, other);
3673                         set_bit(STRIPE_COMPUTE_RUN, &sh->state);
3674                         set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
3675                         set_bit(R5_Wantcompute, &sh->dev[disk_idx].flags);
3676                         set_bit(R5_Wantcompute, &sh->dev[other].flags);
3677                         sh->ops.target = disk_idx;
3678                         sh->ops.target2 = other;
3679                         s->uptodate += 2;
3680                         s->req_compute = 1;
3681                         return 1;
3682                 } else if (test_bit(R5_Insync, &dev->flags)) {
3683                         set_bit(R5_LOCKED, &dev->flags);
3684                         set_bit(R5_Wantread, &dev->flags);
3685                         s->locked++;
3686                         pr_debug("Reading block %d (sync=%d)\n",
3687                                 disk_idx, s->syncing);
3688                 }
3689         }
3690
3691         return 0;
3692 }
3693
3694 /**
3695  * handle_stripe_fill - read or compute data to satisfy pending requests.
3696  */
3697 static void handle_stripe_fill(struct stripe_head *sh,
3698                                struct stripe_head_state *s,
3699                                int disks)
3700 {
3701         int i;
3702
3703         /* look for blocks to read/compute, skip this if a compute
3704          * is already in flight, or if the stripe contents are in the
3705          * midst of changing due to a write
3706          */
3707         if (!test_bit(STRIPE_COMPUTE_RUN, &sh->state) && !sh->check_state &&
3708             !sh->reconstruct_state) {
3709
3710                 /*
3711                  * For degraded stripe with data in journal, do not handle
3712                  * read requests yet, instead, flush the stripe to raid
3713                  * disks first, this avoids handling complex rmw of write
3714                  * back cache (prexor with orig_page, and then xor with
3715                  * page) in the read path
3716                  */
3717                 if (s->injournal && s->failed) {
3718                         if (test_bit(STRIPE_R5C_CACHING, &sh->state))
3719                                 r5c_make_stripe_write_out(sh);
3720                         goto out;
3721                 }
3722
3723                 for (i = disks; i--; )
3724                         if (fetch_block(sh, s, i, disks))
3725                                 break;
3726         }
3727 out:
3728         set_bit(STRIPE_HANDLE, &sh->state);
3729 }
3730
3731 static void break_stripe_batch_list(struct stripe_head *head_sh,
3732                                     unsigned long handle_flags);
3733 /* handle_stripe_clean_event
3734  * any written block on an uptodate or failed drive can be returned.
3735  * Note that if we 'wrote' to a failed drive, it will be UPTODATE, but
3736  * never LOCKED, so we don't need to test 'failed' directly.
3737  */
3738 static void handle_stripe_clean_event(struct r5conf *conf,
3739         struct stripe_head *sh, int disks)
3740 {
3741         int i;
3742         struct r5dev *dev;
3743         int discard_pending = 0;
3744         struct stripe_head *head_sh = sh;
3745         bool do_endio = false;
3746
3747         for (i = disks; i--; )
3748                 if (sh->dev[i].written) {
3749                         dev = &sh->dev[i];
3750                         if (!test_bit(R5_LOCKED, &dev->flags) &&
3751                             (test_bit(R5_UPTODATE, &dev->flags) ||
3752                              test_bit(R5_Discard, &dev->flags) ||
3753                              test_bit(R5_SkipCopy, &dev->flags))) {
3754                                 /* We can return any write requests */
3755                                 struct bio *wbi, *wbi2;
3756                                 pr_debug("Return write for disc %d\n", i);
3757                                 if (test_and_clear_bit(R5_Discard, &dev->flags))
3758                                         clear_bit(R5_UPTODATE, &dev->flags);
3759                                 if (test_and_clear_bit(R5_SkipCopy, &dev->flags)) {
3760                                         WARN_ON(test_bit(R5_UPTODATE, &dev->flags));
3761                                 }
3762                                 do_endio = true;
3763
3764 returnbi:
3765                                 dev->page = dev->orig_page;
3766                                 wbi = dev->written;
3767                                 dev->written = NULL;
3768                                 while (wbi && wbi->bi_iter.bi_sector <
3769                                         dev->sector + STRIPE_SECTORS) {
3770                                         wbi2 = r5_next_bio(wbi, dev->sector);
3771                                         md_write_end(conf->mddev);
3772                                         bio_endio(wbi);
3773                                         wbi = wbi2;
3774                                 }
3775                                 bitmap_endwrite(conf->mddev->bitmap, sh->sector,
3776                                                 STRIPE_SECTORS,
3777                                          !test_bit(STRIPE_DEGRADED, &sh->state),
3778                                                 0);
3779                                 if (head_sh->batch_head) {
3780                                         sh = list_first_entry(&sh->batch_list,
3781                                                               struct stripe_head,
3782                                                               batch_list);
3783                                         if (sh != head_sh) {
3784                                                 dev = &sh->dev[i];
3785                                                 goto returnbi;
3786                                         }
3787                                 }
3788                                 sh = head_sh;
3789                                 dev = &sh->dev[i];
3790                         } else if (test_bit(R5_Discard, &dev->flags))
3791                                 discard_pending = 1;
3792                 }
3793
3794         log_stripe_write_finished(sh);
3795
3796         if (!discard_pending &&
3797             test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags)) {
3798                 int hash;
3799                 clear_bit(R5_Discard, &sh->dev[sh->pd_idx].flags);
3800                 clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
3801                 if (sh->qd_idx >= 0) {
3802                         clear_bit(R5_Discard, &sh->dev[sh->qd_idx].flags);
3803                         clear_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags);
3804                 }
3805                 /* now that discard is done we can proceed with any sync */
3806                 clear_bit(STRIPE_DISCARD, &sh->state);
3807                 /*
3808                  * SCSI discard will change some bio fields and the stripe has
3809                  * no updated data, so remove it from hash list and the stripe
3810                  * will be reinitialized
3811                  */
3812 unhash:
3813                 hash = sh->hash_lock_index;
3814                 spin_lock_irq(conf->hash_locks + hash);
3815                 remove_hash(sh);
3816                 spin_unlock_irq(conf->hash_locks + hash);
3817                 if (head_sh->batch_head) {
3818                         sh = list_first_entry(&sh->batch_list,
3819                                               struct stripe_head, batch_list);
3820                         if (sh != head_sh)
3821                                         goto unhash;
3822                 }
3823                 sh = head_sh;
3824
3825                 if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state))
3826                         set_bit(STRIPE_HANDLE, &sh->state);
3827
3828         }
3829
3830         if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))
3831                 if (atomic_dec_and_test(&conf->pending_full_writes))
3832                         md_wakeup_thread(conf->mddev->thread);
3833
3834         if (head_sh->batch_head && do_endio)
3835                 break_stripe_batch_list(head_sh, STRIPE_EXPAND_SYNC_FLAGS);
3836 }
3837
3838 /*
3839  * For RMW in write back cache, we need extra page in prexor to store the
3840  * old data. This page is stored in dev->orig_page.
3841  *
3842  * This function checks whether we have data for prexor. The exact logic
3843  * is:
3844  *       R5_UPTODATE && (!R5_InJournal || R5_OrigPageUPTDODATE)
3845  */
3846 static inline bool uptodate_for_rmw(struct r5dev *dev)
3847 {
3848         return (test_bit(R5_UPTODATE, &dev->flags)) &&
3849                 (!test_bit(R5_InJournal, &dev->flags) ||
3850                  test_bit(R5_OrigPageUPTDODATE, &dev->flags));
3851 }
3852
3853 static int handle_stripe_dirtying(struct r5conf *conf,
3854                                   struct stripe_head *sh,
3855                                   struct stripe_head_state *s,
3856                                   int disks)
3857 {
3858         int rmw = 0, rcw = 0, i;
3859         sector_t recovery_cp = conf->mddev->recovery_cp;
3860
3861         /* Check whether resync is now happening or should start.
3862          * If yes, then the array is dirty (after unclean shutdown or
3863          * initial creation), so parity in some stripes might be inconsistent.
3864          * In this case, we need to always do reconstruct-write, to ensure
3865          * that in case of drive failure or read-error correction, we
3866          * generate correct data from the parity.
3867          */
3868         if (conf->rmw_level == PARITY_DISABLE_RMW ||
3869             (recovery_cp < MaxSector && sh->sector >= recovery_cp &&
3870              s->failed == 0)) {
3871                 /* Calculate the real rcw later - for now make it
3872                  * look like rcw is cheaper
3873                  */
3874                 rcw = 1; rmw = 2;
3875                 pr_debug("force RCW rmw_level=%u, recovery_cp=%llu sh->sector=%llu\n",
3876                          conf->rmw_level, (unsigned long long)recovery_cp,
3877                          (unsigned long long)sh->sector);
3878         } else for (i = disks; i--; ) {
3879                 /* would I have to read this buffer for read_modify_write */
3880                 struct r5dev *dev = &sh->dev[i];
3881                 if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3882                      i == sh->pd_idx || i == sh->qd_idx ||
3883                      test_bit(R5_InJournal, &dev->flags)) &&
3884                     !test_bit(R5_LOCKED, &dev->flags) &&
3885                     !(uptodate_for_rmw(dev) ||
3886                       test_bit(R5_Wantcompute, &dev->flags))) {
3887                         if (test_bit(R5_Insync, &dev->flags))
3888                                 rmw++;
3889                         else
3890                                 rmw += 2*disks;  /* cannot read it */
3891                 }
3892                 /* Would I have to read this buffer for reconstruct_write */
3893                 if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3894                     i != sh->pd_idx && i != sh->qd_idx &&
3895                     !test_bit(R5_LOCKED, &dev->flags) &&
3896                     !(test_bit(R5_UPTODATE, &dev->flags) ||
3897                       test_bit(R5_Wantcompute, &dev->flags))) {
3898                         if (test_bit(R5_Insync, &dev->flags))
3899                                 rcw++;
3900                         else
3901                                 rcw += 2*disks;
3902                 }
3903         }
3904
3905         pr_debug("for sector %llu state 0x%lx, rmw=%d rcw=%d\n",
3906                  (unsigned long long)sh->sector, sh->state, rmw, rcw);
3907         set_bit(STRIPE_HANDLE, &sh->state);
3908         if ((rmw < rcw || (rmw == rcw && conf->rmw_level == PARITY_PREFER_RMW)) && rmw > 0) {
3909                 /* prefer read-modify-write, but need to get some data */
3910                 if (conf->mddev->queue)
3911                         blk_add_trace_msg(conf->mddev->queue,
3912                                           "raid5 rmw %llu %d",
3913                                           (unsigned long long)sh->sector, rmw);
3914                 for (i = disks; i--; ) {
3915                         struct r5dev *dev = &sh->dev[i];
3916                         if (test_bit(R5_InJournal, &dev->flags) &&
3917                             dev->page == dev->orig_page &&
3918                             !test_bit(R5_LOCKED, &sh->dev[sh->pd_idx].flags)) {
3919                                 /* alloc page for prexor */
3920                                 struct page *p = alloc_page(GFP_NOIO);
3921
3922                                 if (p) {
3923                                         dev->orig_page = p;
3924                                         continue;
3925                                 }
3926
3927                                 /*
3928                                  * alloc_page() failed, try use
3929                                  * disk_info->extra_page
3930                                  */
3931                                 if (!test_and_set_bit(R5C_EXTRA_PAGE_IN_USE,
3932                                                       &conf->cache_state)) {
3933                                         r5c_use_extra_page(sh);
3934                                         break;
3935                                 }
3936
3937                                 /* extra_page in use, add to delayed_list */
3938                                 set_bit(STRIPE_DELAYED, &sh->state);
3939                                 s->waiting_extra_page = 1;
3940                                 return -EAGAIN;
3941                         }
3942                 }
3943
3944                 for (i = disks; i--; ) {
3945                         struct r5dev *dev = &sh->dev[i];
3946                         if (((dev->towrite && !delay_towrite(conf, dev, s)) ||
3947                              i == sh->pd_idx || i == sh->qd_idx ||
3948                              test_bit(R5_InJournal, &dev->flags)) &&
3949                             !test_bit(R5_LOCKED, &dev->flags) &&
3950                             !(uptodate_for_rmw(dev) ||
3951                               test_bit(R5_Wantcompute, &dev->flags)) &&
3952                             test_bit(R5_Insync, &dev->flags)) {
3953                                 if (test_bit(STRIPE_PREREAD_ACTIVE,
3954                                              &sh->state)) {
3955                                         pr_debug("Read_old block %d for r-m-w\n",
3956                                                  i);
3957                                         set_bit(R5_LOCKED, &dev->flags);
3958                                         set_bit(R5_Wantread, &dev->flags);
3959                                         s->locked++;
3960                                 } else {
3961                                         set_bit(STRIPE_DELAYED, &sh->state);
3962                                         set_bit(STRIPE_HANDLE, &sh->state);
3963                                 }
3964                         }
3965                 }
3966         }
3967         if ((rcw < rmw || (rcw == rmw && conf->rmw_level != PARITY_PREFER_RMW)) && rcw > 0) {
3968                 /* want reconstruct write, but need to get some data */
3969                 int qread =0;
3970                 rcw = 0;
3971                 for (i = disks; i--; ) {
3972                         struct r5dev *dev = &sh->dev[i];
3973                         if (!test_bit(R5_OVERWRITE, &dev->flags) &&
3974                             i != sh->pd_idx && i != sh->qd_idx &&
3975                             !test_bit(R5_LOCKED, &dev->flags) &&
3976                             !(test_bit(R5_UPTODATE, &dev->flags) ||
3977                               test_bit(R5_Wantcompute, &dev->flags))) {
3978                                 rcw++;
3979                                 if (test_bit(R5_Insync, &dev->flags) &&
3980                                     test_bit(STRIPE_PREREAD_ACTIVE,
3981                                              &sh->state)) {
3982                                         pr_debug("Read_old block "
3983                                                 "%d for Reconstruct\n", i);
3984                                         set_bit(R5_LOCKED, &dev->flags);
3985                                         set_bit(R5_Wantread, &dev->flags);
3986                                         s->locked++;
3987                                         qread++;
3988                                 } else {
3989                                         set_bit(STRIPE_DELAYED, &sh->state);
3990                                         set_bit(STRIPE_HANDLE, &sh->state);
3991                                 }
3992                         }
3993                 }
3994                 if (rcw && conf->mddev->queue)
3995                         blk_add_trace_msg(conf->mddev->queue, "raid5 rcw %llu %d %d %d",
3996                                           (unsigned long long)sh->sector,
3997                                           rcw, qread, test_bit(STRIPE_DELAYED, &sh->state));
3998         }
3999
4000         if (rcw > disks && rmw > disks &&
4001             !test_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4002                 set_bit(STRIPE_DELAYED, &sh->state);
4003
4004         /* now if nothing is locked, and if we have enough data,
4005          * we can start a write request
4006          */
4007         /* since handle_stripe can be called at any time we need to handle the
4008          * case where a compute block operation has been submitted and then a
4009          * subsequent call wants to start a write request.  raid_run_ops only
4010          * handles the case where compute block and reconstruct are requested
4011          * simultaneously.  If this is not the case then new writes need to be
4012          * held off until the compute completes.
4013          */
4014         if ((s->req_compute || !test_bit(STRIPE_COMPUTE_RUN, &sh->state)) &&
4015             (s->locked == 0 && (rcw == 0 || rmw == 0) &&
4016              !test_bit(STRIPE_BIT_DELAY, &sh->state)))
4017                 schedule_reconstruction(sh, s, rcw == 0, 0);
4018         return 0;
4019 }
4020
4021 static void handle_parity_checks5(struct r5conf *conf, struct stripe_head *sh,
4022                                 struct stripe_head_state *s, int disks)
4023 {
4024         struct r5dev *dev = NULL;
4025
4026         BUG_ON(sh->batch_head);
4027         set_bit(STRIPE_HANDLE, &sh->state);
4028
4029         switch (sh->check_state) {
4030         case check_state_idle:
4031                 /* start a new check operation if there are no failures */
4032                 if (s->failed == 0) {
4033                         BUG_ON(s->uptodate != disks);
4034                         sh->check_state = check_state_run;
4035                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4036                         clear_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags);
4037                         s->uptodate--;
4038                         break;
4039                 }
4040                 dev = &sh->dev[s->failed_num[0]];
4041                 /* fall through */
4042         case check_state_compute_result:
4043                 sh->check_state = check_state_idle;
4044                 if (!dev)
4045                         dev = &sh->dev[sh->pd_idx];
4046
4047                 /* check that a write has not made the stripe insync */
4048                 if (test_bit(STRIPE_INSYNC, &sh->state))
4049                         break;
4050
4051                 /* either failed parity check, or recovery is happening */
4052                 BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));
4053                 BUG_ON(s->uptodate != disks);
4054
4055                 set_bit(R5_LOCKED, &dev->flags);
4056                 s->locked++;
4057                 set_bit(R5_Wantwrite, &dev->flags);
4058
4059                 clear_bit(STRIPE_DEGRADED, &sh->state);
4060                 set_bit(STRIPE_INSYNC, &sh->state);
4061                 break;
4062         case check_state_run:
4063                 break; /* we will be called again upon completion */
4064         case check_state_check_result:
4065                 sh->check_state = check_state_idle;
4066
4067                 /* if a failure occurred during the check operation, leave
4068                  * STRIPE_INSYNC not set and let the stripe be handled again
4069                  */
4070                 if (s->failed)
4071                         break;
4072
4073                 /* handle a successful check operation, if parity is correct
4074                  * we are done.  Otherwise update the mismatch count and repair
4075                  * parity if !MD_RECOVERY_CHECK
4076                  */
4077                 if ((sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) == 0)
4078                         /* parity is correct (on disc,
4079                          * not in buffer any more)
4080                          */
4081                         set_bit(STRIPE_INSYNC, &sh->state);
4082                 else {
4083                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4084                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4085                                 /* don't try to repair!! */
4086                                 set_bit(STRIPE_INSYNC, &sh->state);
4087                                 pr_warn_ratelimited("%s: mismatch sector in range "
4088                                                     "%llu-%llu\n", mdname(conf->mddev),
4089                                                     (unsigned long long) sh->sector,
4090                                                     (unsigned long long) sh->sector +
4091                                                     STRIPE_SECTORS);
4092                         } else {
4093                                 sh->check_state = check_state_compute_run;
4094                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4095                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4096                                 set_bit(R5_Wantcompute,
4097                                         &sh->dev[sh->pd_idx].flags);
4098                                 sh->ops.target = sh->pd_idx;
4099                                 sh->ops.target2 = -1;
4100                                 s->uptodate++;
4101                         }
4102                 }
4103                 break;
4104         case check_state_compute_run:
4105                 break;
4106         default:
4107                 pr_err("%s: unknown check_state: %d sector: %llu\n",
4108                        __func__, sh->check_state,
4109                        (unsigned long long) sh->sector);
4110                 BUG();
4111         }
4112 }
4113
4114 static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh,
4115                                   struct stripe_head_state *s,
4116                                   int disks)
4117 {
4118         int pd_idx = sh->pd_idx;
4119         int qd_idx = sh->qd_idx;
4120         struct r5dev *dev;
4121
4122         BUG_ON(sh->batch_head);
4123         set_bit(STRIPE_HANDLE, &sh->state);
4124
4125         BUG_ON(s->failed > 2);
4126
4127         /* Want to check and possibly repair P and Q.
4128          * However there could be one 'failed' device, in which
4129          * case we can only check one of them, possibly using the
4130          * other to generate missing data
4131          */
4132
4133         switch (sh->check_state) {
4134         case check_state_idle:
4135                 /* start a new check operation if there are < 2 failures */
4136                 if (s->failed == s->q_failed) {
4137                         /* The only possible failed device holds Q, so it
4138                          * makes sense to check P (If anything else were failed,
4139                          * we would have used P to recreate it).
4140                          */
4141                         sh->check_state = check_state_run;
4142                 }
4143                 if (!s->q_failed && s->failed < 2) {
4144                         /* Q is not failed, and we didn't use it to generate
4145                          * anything, so it makes sense to check it
4146                          */
4147                         if (sh->check_state == check_state_run)
4148                                 sh->check_state = check_state_run_pq;
4149                         else
4150                                 sh->check_state = check_state_run_q;
4151                 }
4152
4153                 /* discard potentially stale zero_sum_result */
4154                 sh->ops.zero_sum_result = 0;
4155
4156                 if (sh->check_state == check_state_run) {
4157                         /* async_xor_zero_sum destroys the contents of P */
4158                         clear_bit(R5_UPTODATE, &sh->dev[pd_idx].flags);
4159                         s->uptodate--;
4160                 }
4161                 if (sh->check_state >= check_state_run &&
4162                     sh->check_state <= check_state_run_pq) {
4163                         /* async_syndrome_zero_sum preserves P and Q, so
4164                          * no need to mark them !uptodate here
4165                          */
4166                         set_bit(STRIPE_OP_CHECK, &s->ops_request);
4167                         break;
4168                 }
4169
4170                 /* we have 2-disk failure */
4171                 BUG_ON(s->failed != 2);
4172                 /* fall through */
4173         case check_state_compute_result:
4174                 sh->check_state = check_state_idle;
4175
4176                 /* check that a write has not made the stripe insync */
4177                 if (test_bit(STRIPE_INSYNC, &sh->state))
4178                         break;
4179
4180                 /* now write out any block on a failed drive,
4181                  * or P or Q if they were recomputed
4182                  */
4183                 BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */
4184                 if (s->failed == 2) {
4185                         dev = &sh->dev[s->failed_num[1]];
4186                         s->locked++;
4187                         set_bit(R5_LOCKED, &dev->flags);
4188                         set_bit(R5_Wantwrite, &dev->flags);
4189                 }
4190                 if (s->failed >= 1) {
4191                         dev = &sh->dev[s->failed_num[0]];
4192                         s->locked++;
4193                         set_bit(R5_LOCKED, &dev->flags);
4194                         set_bit(R5_Wantwrite, &dev->flags);
4195                 }
4196                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4197                         dev = &sh->dev[pd_idx];
4198                         s->locked++;
4199                         set_bit(R5_LOCKED, &dev->flags);
4200                         set_bit(R5_Wantwrite, &dev->flags);
4201                 }
4202                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4203                         dev = &sh->dev[qd_idx];
4204                         s->locked++;
4205                         set_bit(R5_LOCKED, &dev->flags);
4206                         set_bit(R5_Wantwrite, &dev->flags);
4207                 }
4208                 clear_bit(STRIPE_DEGRADED, &sh->state);
4209
4210                 set_bit(STRIPE_INSYNC, &sh->state);
4211                 break;
4212         case check_state_run:
4213         case check_state_run_q:
4214         case check_state_run_pq:
4215                 break; /* we will be called again upon completion */
4216         case check_state_check_result:
4217                 sh->check_state = check_state_idle;
4218
4219                 /* handle a successful check operation, if parity is correct
4220                  * we are done.  Otherwise update the mismatch count and repair
4221                  * parity if !MD_RECOVERY_CHECK
4222                  */
4223                 if (sh->ops.zero_sum_result == 0) {
4224                         /* both parities are correct */
4225                         if (!s->failed)
4226                                 set_bit(STRIPE_INSYNC, &sh->state);
4227                         else {
4228                                 /* in contrast to the raid5 case we can validate
4229                                  * parity, but still have a failure to write
4230                                  * back
4231                                  */
4232                                 sh->check_state = check_state_compute_result;
4233                                 /* Returning at this point means that we may go
4234                                  * off and bring p and/or q uptodate again so
4235                                  * we make sure to check zero_sum_result again
4236                                  * to verify if p or q need writeback
4237                                  */
4238                         }
4239                 } else {
4240                         atomic64_add(STRIPE_SECTORS, &conf->mddev->resync_mismatches);
4241                         if (test_bit(MD_RECOVERY_CHECK, &conf->mddev->recovery)) {
4242                                 /* don't try to repair!! */
4243                                 set_bit(STRIPE_INSYNC, &sh->state);
4244                                 pr_warn_ratelimited("%s: mismatch sector in range "
4245                                                     "%llu-%llu\n", mdname(conf->mddev),
4246                                                     (unsigned long long) sh->sector,
4247                                                     (unsigned long long) sh->sector +
4248                                                     STRIPE_SECTORS);
4249                         } else {
4250                                 int *target = &sh->ops.target;
4251
4252                                 sh->ops.target = -1;
4253                                 sh->ops.target2 = -1;
4254                                 sh->check_state = check_state_compute_run;
4255                                 set_bit(STRIPE_COMPUTE_RUN, &sh->state);
4256                                 set_bit(STRIPE_OP_COMPUTE_BLK, &s->ops_request);
4257                                 if (sh->ops.zero_sum_result & SUM_CHECK_P_RESULT) {
4258                                         set_bit(R5_Wantcompute,
4259                                                 &sh->dev[pd_idx].flags);
4260                                         *target = pd_idx;
4261                                         target = &sh->ops.target2;
4262                                         s->uptodate++;
4263                                 }
4264                                 if (sh->ops.zero_sum_result & SUM_CHECK_Q_RESULT) {
4265                                         set_bit(R5_Wantcompute,
4266                                                 &sh->dev[qd_idx].flags);
4267                                         *target = qd_idx;
4268                                         s->uptodate++;
4269                                 }
4270                         }
4271                 }
4272                 break;
4273         case check_state_compute_run:
4274                 break;
4275         default:
4276                 pr_warn("%s: unknown check_state: %d sector: %llu\n",
4277                         __func__, sh->check_state,
4278                         (unsigned long long) sh->sector);
4279                 BUG();
4280         }
4281 }
4282
4283 static void handle_stripe_expansion(struct r5conf *conf, struct stripe_head *sh)
4284 {
4285         int i;
4286
4287         /* We have read all the blocks in this stripe and now we need to
4288          * copy some of them into a target stripe for expand.
4289          */
4290         struct dma_async_tx_descriptor *tx = NULL;
4291         BUG_ON(sh->batch_head);
4292         clear_bit(STRIPE_EXPAND_SOURCE, &sh->state);
4293         for (i = 0; i < sh->disks; i++)
4294                 if (i != sh->pd_idx && i != sh->qd_idx) {
4295                         int dd_idx, j;
4296                         struct stripe_head *sh2;
4297                         struct async_submit_ctl submit;
4298
4299                         sector_t bn = raid5_compute_blocknr(sh, i, 1);
4300                         sector_t s = raid5_compute_sector(conf, bn, 0,
4301                                                           &dd_idx, NULL);
4302                         sh2 = raid5_get_active_stripe(conf, s, 0, 1, 1);
4303                         if (sh2 == NULL)
4304                                 /* so far only the early blocks of this stripe
4305                                  * have been requested.  When later blocks
4306                                  * get requested, we will try again
4307                                  */
4308                                 continue;
4309                         if (!test_bit(STRIPE_EXPANDING, &sh2->state) ||
4310                            test_bit(R5_Expanded, &sh2->dev[dd_idx].flags)) {
4311                                 /* must have already done this block */
4312                                 raid5_release_stripe(sh2);
4313                                 continue;
4314                         }
4315
4316                         /* place all the copies on one channel */
4317                         init_async_submit(&submit, 0, tx, NULL, NULL, NULL);
4318                         tx = async_memcpy(sh2->dev[dd_idx].page,
4319                                           sh->dev[i].page, 0, 0, STRIPE_SIZE,
4320                                           &submit);
4321
4322                         set_bit(R5_Expanded, &sh2->dev[dd_idx].flags);
4323                         set_bit(R5_UPTODATE, &sh2->dev[dd_idx].flags);
4324                         for (j = 0; j < conf->raid_disks; j++)
4325                                 if (j != sh2->pd_idx &&
4326                                     j != sh2->qd_idx &&
4327                                     !test_bit(R5_Expanded, &sh2->dev[j].flags))
4328                                         break;
4329                         if (j == conf->raid_disks) {
4330                                 set_bit(STRIPE_EXPAND_READY, &sh2->state);
4331                                 set_bit(STRIPE_HANDLE, &sh2->state);
4332                         }
4333                         raid5_release_stripe(sh2);
4334
4335                 }
4336         /* done submitting copies, wait for them to complete */
4337         async_tx_quiesce(&tx);
4338 }
4339
4340 /*
4341  * handle_stripe - do things to a stripe.
4342  *
4343  * We lock the stripe by setting STRIPE_ACTIVE and then examine the
4344  * state of various bits to see what needs to be done.
4345  * Possible results:
4346  *    return some read requests which now have data
4347  *    return some write requests which are safely on storage
4348  *    schedule a read on some buffers
4349  *    schedule a write of some buffers
4350  *    return confirmation of parity correctness
4351  *
4352  */
4353
4354 static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s)
4355 {
4356         struct r5conf *conf = sh->raid_conf;
4357         int disks = sh->disks;
4358         struct r5dev *dev;
4359         int i;
4360         int do_recovery = 0;
4361
4362         memset(s, 0, sizeof(*s));
4363
4364         s->expanding = test_bit(STRIPE_EXPAND_SOURCE, &sh->state) && !sh->batch_head;
4365         s->expanded = test_bit(STRIPE_EXPAND_READY, &sh->state) && !sh->batch_head;
4366         s->failed_num[0] = -1;
4367         s->failed_num[1] = -1;
4368         s->log_failed = r5l_log_disk_error(conf);
4369
4370         /* Now to look around and see what can be done */
4371         rcu_read_lock();
4372         for (i=disks; i--; ) {
4373                 struct md_rdev *rdev;
4374                 sector_t first_bad;
4375                 int bad_sectors;
4376                 int is_bad = 0;
4377
4378                 dev = &sh->dev[i];
4379
4380                 pr_debug("check %d: state 0x%lx read %p write %p written %p\n",
4381                          i, dev->flags,
4382                          dev->toread, dev->towrite, dev->written);
4383                 /* maybe we can reply to a read
4384                  *
4385                  * new wantfill requests are only permitted while
4386                  * ops_complete_biofill is guaranteed to be inactive
4387                  */
4388                 if (test_bit(R5_UPTODATE, &dev->flags) && dev->toread &&
4389                     !test_bit(STRIPE_BIOFILL_RUN, &sh->state))
4390                         set_bit(R5_Wantfill, &dev->flags);
4391
4392                 /* now count some things */
4393                 if (test_bit(R5_LOCKED, &dev->flags))
4394                         s->locked++;
4395                 if (test_bit(R5_UPTODATE, &dev->flags))
4396                         s->uptodate++;
4397                 if (test_bit(R5_Wantcompute, &dev->flags)) {
4398                         s->compute++;
4399                         BUG_ON(s->compute > 2);
4400                 }
4401
4402                 if (test_bit(R5_Wantfill, &dev->flags))
4403                         s->to_fill++;
4404                 else if (dev->toread)
4405                         s->to_read++;
4406                 if (dev->towrite) {
4407                         s->to_write++;
4408                         if (!test_bit(R5_OVERWRITE, &dev->flags))
4409                                 s->non_overwrite++;
4410                 }
4411                 if (dev->written)
4412                         s->written++;
4413                 /* Prefer to use the replacement for reads, but only
4414                  * if it is recovered enough and has no bad blocks.
4415                  */
4416                 rdev = rcu_dereference(conf->disks[i].replacement);
4417                 if (rdev && !test_bit(Faulty, &rdev->flags) &&
4418                     rdev->recovery_offset >= sh->sector + STRIPE_SECTORS &&
4419                     !is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4420                                  &first_bad, &bad_sectors))
4421                         set_bit(R5_ReadRepl, &dev->flags);
4422                 else {
4423                         if (rdev && !test_bit(Faulty, &rdev->flags))
4424                                 set_bit(R5_NeedReplace, &dev->flags);
4425                         else
4426                                 clear_bit(R5_NeedReplace, &dev->flags);
4427                         rdev = rcu_dereference(conf->disks[i].rdev);
4428                         clear_bit(R5_ReadRepl, &dev->flags);
4429                 }
4430                 if (rdev && test_bit(Faulty, &rdev->flags))
4431                         rdev = NULL;
4432                 if (rdev) {
4433                         is_bad = is_badblock(rdev, sh->sector, STRIPE_SECTORS,
4434                                              &first_bad, &bad_sectors);
4435                         if (s->blocked_rdev == NULL
4436                             && (test_bit(Blocked, &rdev->flags)
4437                                 || is_bad < 0)) {
4438                                 if (is_bad < 0)
4439                                         set_bit(BlockedBadBlocks,
4440                                                 &rdev->flags);
4441                                 s->blocked_rdev = rdev;
4442                                 atomic_inc(&rdev->nr_pending);
4443                         }
4444                 }
4445                 clear_bit(R5_Insync, &dev->flags);
4446                 if (!rdev)
4447                         /* Not in-sync */;
4448                 else if (is_bad) {
4449                         /* also not in-sync */
4450                         if (!test_bit(WriteErrorSeen, &rdev->flags) &&
4451                             test_bit(R5_UPTODATE, &dev->flags)) {
4452                                 /* treat as in-sync, but with a read error
4453                                  * which we can now try to correct
4454                                  */
4455                                 set_bit(R5_Insync, &dev->flags);
4456                                 set_bit(R5_ReadError, &dev->flags);
4457                         }
4458                 } else if (test_bit(In_sync, &rdev->flags))
4459                         set_bit(R5_Insync, &dev->flags);
4460                 else if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)
4461                         /* in sync if before recovery_offset */
4462                         set_bit(R5_Insync, &dev->flags);
4463                 else if (test_bit(R5_UPTODATE, &dev->flags) &&
4464                          test_bit(R5_Expanded, &dev->flags))
4465                         /* If we've reshaped into here, we assume it is Insync.
4466                          * We will shortly update recovery_offset to make
4467                          * it official.
4468                          */
4469                         set_bit(R5_Insync, &dev->flags);
4470
4471                 if (test_bit(R5_WriteError, &dev->flags)) {
4472                         /* This flag does not apply to '.replacement'
4473                          * only to .rdev, so make sure to check that*/
4474                         struct md_rdev *rdev2 = rcu_dereference(
4475                                 conf->disks[i].rdev);
4476                         if (rdev2 == rdev)
4477                                 clear_bit(R5_Insync, &dev->flags);
4478                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4479                                 s->handle_bad_blocks = 1;
4480                                 atomic_inc(&rdev2->nr_pending);
4481                         } else
4482                                 clear_bit(R5_WriteError, &dev->flags);
4483                 }
4484                 if (test_bit(R5_MadeGood, &dev->flags)) {
4485                         /* This flag does not apply to '.replacement'
4486                          * only to .rdev, so make sure to check that*/
4487                         struct md_rdev *rdev2 = rcu_dereference(
4488                                 conf->disks[i].rdev);
4489                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4490                                 s->handle_bad_blocks = 1;
4491                                 atomic_inc(&rdev2->nr_pending);
4492                         } else
4493                                 clear_bit(R5_MadeGood, &dev->flags);
4494                 }
4495                 if (test_bit(R5_MadeGoodRepl, &dev->flags)) {
4496                         struct md_rdev *rdev2 = rcu_dereference(
4497                                 conf->disks[i].replacement);
4498                         if (rdev2 && !test_bit(Faulty, &rdev2->flags)) {
4499                                 s->handle_bad_blocks = 1;
4500                                 atomic_inc(&rdev2->nr_pending);
4501                         } else
4502                                 clear_bit(R5_MadeGoodRepl, &dev->flags);
4503                 }
4504                 if (!test_bit(R5_Insync, &dev->flags)) {
4505                         /* The ReadError flag will just be confusing now */
4506                         clear_bit(R5_ReadError, &dev->flags);
4507                         clear_bit(R5_ReWrite, &dev->flags);
4508                 }
4509                 if (test_bit(R5_ReadError, &dev->flags))
4510                         clear_bit(R5_Insync, &dev->flags);
4511                 if (!test_bit(R5_Insync, &dev->flags)) {
4512                         if (s->failed < 2)
4513                                 s->failed_num[s->failed] = i;
4514                         s->failed++;
4515                         if (rdev && !test_bit(Faulty, &rdev->flags))
4516                                 do_recovery = 1;
4517                 }
4518
4519                 if (test_bit(R5_InJournal, &dev->flags))
4520                         s->injournal++;
4521                 if (test_bit(R5_InJournal, &dev->flags) && dev->written)
4522                         s->just_cached++;
4523         }
4524         if (test_bit(STRIPE_SYNCING, &sh->state)) {
4525                 /* If there is a failed device being replaced,
4526                  *     we must be recovering.
4527                  * else if we are after recovery_cp, we must be syncing
4528                  * else if MD_RECOVERY_REQUESTED is set, we also are syncing.
4529                  * else we can only be replacing
4530                  * sync and recovery both need to read all devices, and so
4531                  * use the same flag.
4532                  */
4533                 if (do_recovery ||
4534                     sh->sector >= conf->mddev->recovery_cp ||
4535                     test_bit(MD_RECOVERY_REQUESTED, &(conf->mddev->recovery)))
4536                         s->syncing = 1;
4537                 else
4538                         s->replacing = 1;
4539         }
4540         rcu_read_unlock();
4541 }
4542
4543 static int clear_batch_ready(struct stripe_head *sh)
4544 {
4545         /* Return '1' if this is a member of batch, or
4546          * '0' if it is a lone stripe or a head which can now be
4547          * handled.
4548          */
4549         struct stripe_head *tmp;
4550         if (!test_and_clear_bit(STRIPE_BATCH_READY, &sh->state))
4551                 return (sh->batch_head && sh->batch_head != sh);
4552         spin_lock(&sh->stripe_lock);
4553         if (!sh->batch_head) {
4554                 spin_unlock(&sh->stripe_lock);
4555                 return 0;
4556         }
4557
4558         /*
4559          * this stripe could be added to a batch list before we check
4560          * BATCH_READY, skips it
4561          */
4562         if (sh->batch_head != sh) {
4563                 spin_unlock(&sh->stripe_lock);
4564                 return 1;
4565         }
4566         spin_lock(&sh->batch_lock);
4567         list_for_each_entry(tmp, &sh->batch_list, batch_list)
4568                 clear_bit(STRIPE_BATCH_READY, &tmp->state);
4569         spin_unlock(&sh->batch_lock);
4570         spin_unlock(&sh->stripe_lock);
4571
4572         /*
4573          * BATCH_READY is cleared, no new stripes can be added.
4574          * batch_list can be accessed without lock
4575          */
4576         return 0;
4577 }
4578
4579 static void break_stripe_batch_list(struct stripe_head *head_sh,
4580                                     unsigned long handle_flags)
4581 {
4582         struct stripe_head *sh, *next;
4583         int i;
4584         int do_wakeup = 0;
4585
4586         list_for_each_entry_safe(sh, next, &head_sh->batch_list, batch_list) {
4587
4588                 list_del_init(&sh->batch_list);
4589
4590                 WARN_ONCE(sh->state & ((1 << STRIPE_ACTIVE) |
4591                                           (1 << STRIPE_SYNCING) |
4592                                           (1 << STRIPE_REPLACED) |
4593                                           (1 << STRIPE_DELAYED) |
4594                                           (1 << STRIPE_BIT_DELAY) |
4595                                           (1 << STRIPE_FULL_WRITE) |
4596                                           (1 << STRIPE_BIOFILL_RUN) |
4597                                           (1 << STRIPE_COMPUTE_RUN)  |
4598                                           (1 << STRIPE_OPS_REQ_PENDING) |
4599                                           (1 << STRIPE_DISCARD) |
4600                                           (1 << STRIPE_BATCH_READY) |
4601                                           (1 << STRIPE_BATCH_ERR) |
4602                                           (1 << STRIPE_BITMAP_PENDING)),
4603                         "stripe state: %lx\n", sh->state);
4604                 WARN_ONCE(head_sh->state & ((1 << STRIPE_DISCARD) |
4605                                               (1 << STRIPE_REPLACED)),
4606                         "head stripe state: %lx\n", head_sh->state);
4607
4608                 set_mask_bits(&sh->state, ~(STRIPE_EXPAND_SYNC_FLAGS |
4609                                             (1 << STRIPE_PREREAD_ACTIVE) |
4610                                             (1 << STRIPE_DEGRADED) |
4611                                             (1 << STRIPE_ON_UNPLUG_LIST)),
4612                               head_sh->state & (1 << STRIPE_INSYNC));
4613
4614                 sh->check_state = head_sh->check_state;
4615                 sh->reconstruct_state = head_sh->reconstruct_state;
4616                 for (i = 0; i < sh->disks; i++) {
4617                         if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
4618                                 do_wakeup = 1;
4619                         sh->dev[i].flags = head_sh->dev[i].flags &
4620                                 (~((1 << R5_WriteError) | (1 << R5_Overlap)));
4621                 }
4622                 spin_lock_irq(&sh->stripe_lock);
4623                 sh->batch_head = NULL;
4624                 spin_unlock_irq(&sh->stripe_lock);
4625                 if (handle_flags == 0 ||
4626                     sh->state & handle_flags)
4627                         set_bit(STRIPE_HANDLE, &sh->state);
4628                 raid5_release_stripe(sh);
4629         }
4630         spin_lock_irq(&head_sh->stripe_lock);
4631         head_sh->batch_head = NULL;
4632         spin_unlock_irq(&head_sh->stripe_lock);
4633         for (i = 0; i < head_sh->disks; i++)
4634                 if (test_and_clear_bit(R5_Overlap, &head_sh->dev[i].flags))
4635                         do_wakeup = 1;
4636         if (head_sh->state & handle_flags)
4637                 set_bit(STRIPE_HANDLE, &head_sh->state);
4638
4639         if (do_wakeup)
4640                 wake_up(&head_sh->raid_conf->wait_for_overlap);
4641 }
4642
4643 static void handle_stripe(struct stripe_head *sh)
4644 {
4645         struct stripe_head_state s;
4646         struct r5conf *conf = sh->raid_conf;
4647         int i;
4648         int prexor;
4649         int disks = sh->disks;
4650         struct r5dev *pdev, *qdev;
4651
4652         clear_bit(STRIPE_HANDLE, &sh->state);
4653         if (test_and_set_bit_lock(STRIPE_ACTIVE, &sh->state)) {
4654                 /* already being handled, ensure it gets handled
4655                  * again when current action finishes */
4656                 set_bit(STRIPE_HANDLE, &sh->state);
4657                 return;
4658         }
4659
4660         if (clear_batch_ready(sh) ) {
4661                 clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
4662                 return;
4663         }
4664
4665         if (test_and_clear_bit(STRIPE_BATCH_ERR, &sh->state))
4666                 break_stripe_batch_list(sh, 0);
4667
4668         if (test_bit(STRIPE_SYNC_REQUESTED, &sh->state) && !sh->batch_head) {
4669                 spin_lock(&sh->stripe_lock);
4670                 /*
4671                  * Cannot process 'sync' concurrently with 'discard'.
4672                  * Flush data in r5cache before 'sync'.
4673                  */
4674                 if (!test_bit(STRIPE_R5C_PARTIAL_STRIPE, &sh->state) &&
4675                     !test_bit(STRIPE_R5C_FULL_STRIPE, &sh->state) &&
4676                     !test_bit(STRIPE_DISCARD, &sh->state) &&
4677                     test_and_clear_bit(STRIPE_SYNC_REQUESTED, &sh->state)) {
4678                         set_bit(STRIPE_SYNCING, &sh->state);
4679                         clear_bit(STRIPE_INSYNC, &sh->state);
4680                         clear_bit(STRIPE_REPLACED, &sh->state);
4681                 }
4682                 spin_unlock(&sh->stripe_lock);
4683         }
4684         clear_bit(STRIPE_DELAYED, &sh->state);
4685
4686         pr_debug("handling stripe %llu, state=%#lx cnt=%d, "
4687                 "pd_idx=%d, qd_idx=%d\n, check:%d, reconstruct:%d\n",
4688                (unsigned long long)sh->sector, sh->state,
4689                atomic_read(&sh->count), sh->pd_idx, sh->qd_idx,
4690                sh->check_state, sh->reconstruct_state);
4691
4692         analyse_stripe(sh, &s);
4693
4694         if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
4695                 goto finish;
4696
4697         if (s.handle_bad_blocks ||
4698             test_bit(MD_SB_CHANGE_PENDING, &conf->mddev->sb_flags)) {
4699                 set_bit(STRIPE_HANDLE, &sh->state);
4700                 goto finish;
4701         }
4702
4703         if (unlikely(s.blocked_rdev)) {
4704                 if (s.syncing || s.expanding || s.expanded ||
4705                     s.replacing || s.to_write || s.written) {
4706                         set_bit(STRIPE_HANDLE, &sh->state);
4707                         goto finish;
4708                 }
4709                 /* There is nothing for the blocked_rdev to block */
4710                 rdev_dec_pending(s.blocked_rdev, conf->mddev);
4711                 s.blocked_rdev = NULL;
4712         }
4713
4714         if (s.to_fill && !test_bit(STRIPE_BIOFILL_RUN, &sh->state)) {
4715                 set_bit(STRIPE_OP_BIOFILL, &s.ops_request);
4716                 set_bit(STRIPE_BIOFILL_RUN, &sh->state);
4717         }
4718
4719         pr_debug("locked=%d uptodate=%d to_read=%d"
4720                " to_write=%d failed=%d failed_num=%d,%d\n",
4721                s.locked, s.uptodate, s.to_read, s.to_write, s.failed,
4722                s.failed_num[0], s.failed_num[1]);
4723         /*
4724          * check if the array has lost more than max_degraded devices and,
4725          * if so, some requests might need to be failed.
4726          *
4727          * When journal device failed (log_failed), we will only process
4728          * the stripe if there is data need write to raid disks
4729          */
4730         if (s.failed > conf->max_degraded ||
4731             (s.log_failed && s.injournal == 0)) {
4732                 sh->check_state = 0;
4733                 sh->reconstruct_state = 0;
4734                 break_stripe_batch_list(sh, 0);
4735                 if (s.to_read+s.to_write+s.written)
4736                         handle_failed_stripe(conf, sh, &s, disks);
4737                 if (s.syncing + s.replacing)
4738                         handle_failed_sync(conf, sh, &s);
4739         }
4740
4741         /* Now we check to see if any write operations have recently
4742          * completed
4743          */
4744         prexor = 0;
4745         if (sh->reconstruct_state == reconstruct_state_prexor_drain_result)
4746                 prexor = 1;
4747         if (sh->reconstruct_state == reconstruct_state_drain_result ||
4748             sh->reconstruct_state == reconstruct_state_prexor_drain_result) {
4749                 sh->reconstruct_state = reconstruct_state_idle;
4750
4751                 /* All the 'written' buffers and the parity block are ready to
4752                  * be written back to disk
4753                  */
4754                 BUG_ON(!test_bit(R5_UPTODATE, &sh->dev[sh->pd_idx].flags) &&
4755                        !test_bit(R5_Discard, &sh->dev[sh->pd_idx].flags));
4756                 BUG_ON(sh->qd_idx >= 0 &&
4757                        !test_bit(R5_UPTODATE, &sh->dev[sh->qd_idx].flags) &&
4758                        !test_bit(R5_Discard, &sh->dev[sh->qd_idx].flags));
4759                 for (i = disks; i--; ) {
4760                         struct r5dev *dev = &sh->dev[i];
4761                         if (test_bit(R5_LOCKED, &dev->flags) &&
4762                                 (i == sh->pd_idx || i == sh->qd_idx ||
4763                                  dev->written || test_bit(R5_InJournal,
4764                                                           &dev->flags))) {
4765                                 pr_debug("Writing block %d\n", i);
4766                                 set_bit(R5_Wantwrite, &dev->flags);
4767                                 if (prexor)
4768                                         continue;
4769                                 if (s.failed > 1)
4770                                         continue;
4771                                 if (!test_bit(R5_Insync, &dev->flags) ||
4772                                     ((i == sh->pd_idx || i == sh->qd_idx)  &&
4773                                      s.failed == 0))
4774                                         set_bit(STRIPE_INSYNC, &sh->state);
4775                         }
4776                 }
4777                 if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
4778                         s.dec_preread_active = 1;
4779         }
4780
4781         /*
4782          * might be able to return some write requests if the parity blocks
4783          * are safe, or on a failed drive
4784          */
4785         pdev = &sh->dev[sh->pd_idx];
4786         s.p_failed = (s.failed >= 1 && s.failed_num[0] == sh->pd_idx)
4787                 || (s.failed >= 2 && s.failed_num[1] == sh->pd_idx);
4788         qdev = &sh->dev[sh->qd_idx];
4789         s.q_failed = (s.failed >= 1 && s.failed_num[0] == sh->qd_idx)
4790                 || (s.failed >= 2 && s.failed_num[1] == sh->qd_idx)
4791                 || conf->level < 6;
4792
4793         if (s.written &&
4794             (s.p_failed || ((test_bit(R5_Insync, &pdev->flags)
4795                              && !test_bit(R5_LOCKED, &pdev->flags)
4796                              && (test_bit(R5_UPTODATE, &pdev->flags) ||
4797                                  test_bit(R5_Discard, &pdev->flags))))) &&
4798             (s.q_failed || ((test_bit(R5_Insync, &qdev->flags)
4799                              && !test_bit(R5_LOCKED, &qdev->flags)
4800                              && (test_bit(R5_UPTODATE, &qdev->flags) ||
4801                                  test_bit(R5_Discard, &qdev->flags))))))
4802                 handle_stripe_clean_event(conf, sh, disks);
4803
4804         if (s.just_cached)
4805                 r5c_handle_cached_data_endio(conf, sh, disks);
4806         log_stripe_write_finished(sh);
4807
4808         /* Now we might consider reading some blocks, either to check/generate
4809          * parity, or to satisfy requests
4810          * or to load a block that is being partially written.
4811          */
4812         if (s.to_read || s.non_overwrite
4813             || (conf->level == 6 && s.to_write && s.failed)
4814             || (s.syncing && (s.uptodate + s.compute < disks))
4815             || s.replacing
4816             || s.expanding)
4817                 handle_stripe_fill(sh, &s, disks);
4818
4819         /*
4820          * When the stripe finishes full journal write cycle (write to journal
4821          * and raid disk), this is the clean up procedure so it is ready for
4822          * next operation.
4823          */
4824         r5c_finish_stripe_write_out(conf, sh, &s);
4825
4826         /*
4827          * Now to consider new write requests, cache write back and what else,
4828          * if anything should be read.  We do not handle new writes when:
4829          * 1/ A 'write' operation (copy+xor) is already in flight.
4830          * 2/ A 'check' operation is in flight, as it may clobber the parity
4831          *    block.
4832          * 3/ A r5c cache log write is in flight.
4833          */
4834
4835         if (!sh->reconstruct_state && !sh->check_state && !sh->log_io) {
4836                 if (!r5c_is_writeback(conf->log)) {
4837                         if (s.to_write)
4838                                 handle_stripe_dirtying(conf, sh, &s, disks);
4839                 } else { /* write back cache */
4840                         int ret = 0;
4841
4842                         /* First, try handle writes in caching phase */
4843                         if (s.to_write)
4844                                 ret = r5c_try_caching_write(conf, sh, &s,
4845                                                             disks);
4846                         /*
4847                          * If caching phase failed: ret == -EAGAIN
4848                          *    OR
4849                          * stripe under reclaim: !caching && injournal
4850                          *
4851                          * fall back to handle_stripe_dirtying()
4852                          */
4853                         if (ret == -EAGAIN ||
4854                             /* stripe under reclaim: !caching && injournal */
4855                             (!test_bit(STRIPE_R5C_CACHING, &sh->state) &&
4856                              s.injournal > 0)) {
4857                                 ret = handle_stripe_dirtying(conf, sh, &s,
4858                                                              disks);
4859                                 if (ret == -EAGAIN)
4860                                         goto finish;
4861                         }
4862                 }
4863         }
4864
4865         /* maybe we need to check and possibly fix the parity for this stripe
4866          * Any reads will already have been scheduled, so we just see if enough
4867          * data is available.  The parity check is held off while parity
4868          * dependent operations are in flight.
4869          */
4870         if (sh->check_state ||
4871             (s.syncing && s.locked == 0 &&
4872              !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4873              !test_bit(STRIPE_INSYNC, &sh->state))) {
4874                 if (conf->level == 6)
4875                         handle_parity_checks6(conf, sh, &s, disks);
4876                 else
4877                         handle_parity_checks5(conf, sh, &s, disks);
4878         }
4879
4880         if ((s.replacing || s.syncing) && s.locked == 0
4881             && !test_bit(STRIPE_COMPUTE_RUN, &sh->state)
4882             && !test_bit(STRIPE_REPLACED, &sh->state)) {
4883                 /* Write out to replacement devices where possible */
4884                 for (i = 0; i < conf->raid_disks; i++)
4885                         if (test_bit(R5_NeedReplace, &sh->dev[i].flags)) {
4886                                 WARN_ON(!test_bit(R5_UPTODATE, &sh->dev[i].flags));
4887                                 set_bit(R5_WantReplace, &sh->dev[i].flags);
4888                                 set_bit(R5_LOCKED, &sh->dev[i].flags);
4889                                 s.locked++;
4890                         }
4891                 if (s.replacing)
4892                         set_bit(STRIPE_INSYNC, &sh->state);
4893                 set_bit(STRIPE_REPLACED, &sh->state);
4894         }
4895         if ((s.syncing || s.replacing) && s.locked == 0 &&
4896             !test_bit(STRIPE_COMPUTE_RUN, &sh->state) &&
4897             test_bit(STRIPE_INSYNC, &sh->state)) {
4898                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4899                 clear_bit(STRIPE_SYNCING, &sh->state);
4900                 if (test_and_clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags))
4901                         wake_up(&conf->wait_for_overlap);
4902         }
4903
4904         /* If the failed drives are just a ReadError, then we might need
4905          * to progress the repair/check process
4906          */
4907         if (s.failed <= conf->max_degraded && !conf->mddev->ro)
4908                 for (i = 0; i < s.failed; i++) {
4909                         struct r5dev *dev = &sh->dev[s.failed_num[i]];
4910                         if (test_bit(R5_ReadError, &dev->flags)
4911                             && !test_bit(R5_LOCKED, &dev->flags)
4912                             && test_bit(R5_UPTODATE, &dev->flags)
4913                                 ) {
4914                                 if (!test_bit(R5_ReWrite, &dev->flags)) {
4915                                         set_bit(R5_Wantwrite, &dev->flags);
4916                                         set_bit(R5_ReWrite, &dev->flags);
4917                                         set_bit(R5_LOCKED, &dev->flags);
4918                                         s.locked++;
4919                                 } else {
4920                                         /* let's read it back */
4921                                         set_bit(R5_Wantread, &dev->flags);
4922                                         set_bit(R5_LOCKED, &dev->flags);
4923                                         s.locked++;
4924                                 }
4925                         }
4926                 }
4927
4928         /* Finish reconstruct operations initiated by the expansion process */
4929         if (sh->reconstruct_state == reconstruct_state_result) {
4930                 struct stripe_head *sh_src
4931                         = raid5_get_active_stripe(conf, sh->sector, 1, 1, 1);
4932                 if (sh_src && test_bit(STRIPE_EXPAND_SOURCE, &sh_src->state)) {
4933                         /* sh cannot be written until sh_src has been read.
4934                          * so arrange for sh to be delayed a little
4935                          */
4936                         set_bit(STRIPE_DELAYED, &sh->state);
4937                         set_bit(STRIPE_HANDLE, &sh->state);
4938                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE,
4939                                               &sh_src->state))
4940                                 atomic_inc(&conf->preread_active_stripes);
4941                         raid5_release_stripe(sh_src);
4942                         goto finish;
4943                 }
4944                 if (sh_src)
4945                         raid5_release_stripe(sh_src);
4946
4947                 sh->reconstruct_state = reconstruct_state_idle;
4948                 clear_bit(STRIPE_EXPANDING, &sh->state);
4949                 for (i = conf->raid_disks; i--; ) {
4950                         set_bit(R5_Wantwrite, &sh->dev[i].flags);
4951                         set_bit(R5_LOCKED, &sh->dev[i].flags);
4952                         s.locked++;
4953                 }
4954         }
4955
4956         if (s.expanded && test_bit(STRIPE_EXPANDING, &sh->state) &&
4957             !sh->reconstruct_state) {
4958                 /* Need to write out all blocks after computing parity */
4959                 sh->disks = conf->raid_disks;
4960                 stripe_set_idx(sh->sector, conf, 0, sh);
4961                 schedule_reconstruction(sh, &s, 1, 1);
4962         } else if (s.expanded && !sh->reconstruct_state && s.locked == 0) {
4963                 clear_bit(STRIPE_EXPAND_READY, &sh->state);
4964                 atomic_dec(&conf->reshape_stripes);
4965                 wake_up(&conf->wait_for_overlap);
4966                 md_done_sync(conf->mddev, STRIPE_SECTORS, 1);
4967         }
4968
4969         if (s.expanding && s.locked == 0 &&
4970             !test_bit(STRIPE_COMPUTE_RUN, &sh->state))
4971                 handle_stripe_expansion(conf, sh);
4972
4973 finish:
4974         /* wait for this device to become unblocked */
4975         if (unlikely(s.blocked_rdev)) {
4976                 if (conf->mddev->external)
4977                         md_wait_for_blocked_rdev(s.blocked_rdev,
4978                                                  conf->mddev);
4979                 else
4980                         /* Internal metadata will immediately
4981                          * be written by raid5d, so we don't
4982                          * need to wait here.
4983                          */
4984                         rdev_dec_pending(s.blocked_rdev,
4985                                          conf->mddev);
4986         }
4987
4988         if (s.handle_bad_blocks)
4989                 for (i = disks; i--; ) {
4990                         struct md_rdev *rdev;
4991                         struct r5dev *dev = &sh->dev[i];
4992                         if (test_and_clear_bit(R5_WriteError, &dev->flags)) {
4993                                 /* We own a safe reference to the rdev */
4994                                 rdev = conf->disks[i].rdev;
4995                                 if (!rdev_set_badblocks(rdev, sh->sector,
4996                                                         STRIPE_SECTORS, 0))
4997                                         md_error(conf->mddev, rdev);
4998                                 rdev_dec_pending(rdev, conf->mddev);
4999                         }
5000                         if (test_and_clear_bit(R5_MadeGood, &dev->flags)) {
5001                                 rdev = conf->disks[i].rdev;
5002                                 rdev_clear_badblocks(rdev, sh->sector,
5003                                                      STRIPE_SECTORS, 0);
5004                                 rdev_dec_pending(rdev, conf->mddev);
5005                         }
5006                         if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) {
5007                                 rdev = conf->disks[i].replacement;
5008                                 if (!rdev)
5009                                         /* rdev have been moved down */
5010                                         rdev = conf->disks[i].rdev;
5011                                 rdev_clear_badblocks(rdev, sh->sector,
5012                                                      STRIPE_SECTORS, 0);
5013                                 rdev_dec_pending(rdev, conf->mddev);
5014                         }
5015                 }
5016
5017         if (s.ops_request)
5018                 raid_run_ops(sh, s.ops_request);
5019
5020         ops_run_io(sh, &s);
5021
5022         if (s.dec_preread_active) {
5023                 /* We delay this until after ops_run_io so that if make_request
5024                  * is waiting on a flush, it won't continue until the writes
5025                  * have actually been submitted.
5026                  */
5027                 atomic_dec(&conf->preread_active_stripes);
5028                 if (atomic_read(&conf->preread_active_stripes) <
5029                     IO_THRESHOLD)
5030                         md_wakeup_thread(conf->mddev->thread);
5031         }
5032
5033         clear_bit_unlock(STRIPE_ACTIVE, &sh->state);
5034 }
5035
5036 static void raid5_activate_delayed(struct r5conf *conf)
5037 {
5038         if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
5039                 while (!list_empty(&conf->delayed_list)) {
5040                         struct list_head *l = conf->delayed_list.next;
5041                         struct stripe_head *sh;
5042                         sh = list_entry(l, struct stripe_head, lru);
5043                         list_del_init(l);
5044                         clear_bit(STRIPE_DELAYED, &sh->state);
5045                         if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5046                                 atomic_inc(&conf->preread_active_stripes);
5047                         list_add_tail(&sh->lru, &conf->hold_list);
5048                         raid5_wakeup_stripe_thread(sh);
5049                 }
5050         }
5051 }
5052
5053 static void activate_bit_delay(struct r5conf *conf,
5054         struct list_head *temp_inactive_list)
5055 {
5056         /* device_lock is held */
5057         struct list_head head;
5058         list_add(&head, &conf->bitmap_list);
5059         list_del_init(&conf->bitmap_list);
5060         while (!list_empty(&head)) {
5061                 struct stripe_head *sh = list_entry(head.next, struct stripe_head, lru);
5062                 int hash;
5063                 list_del_init(&sh->lru);
5064                 atomic_inc(&sh->count);
5065                 hash = sh->hash_lock_index;
5066                 __release_stripe(conf, sh, &temp_inactive_list[hash]);
5067         }
5068 }
5069
5070 static int raid5_congested(struct mddev *mddev, int bits)
5071 {
5072         struct r5conf *conf = mddev->private;
5073
5074         /* No difference between reads and writes.  Just check
5075          * how busy the stripe_cache is
5076          */
5077
5078         if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
5079                 return 1;
5080
5081         /* Also checks whether there is pressure on r5cache log space */
5082         if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
5083                 return 1;
5084         if (conf->quiesce)
5085                 return 1;
5086         if (atomic_read(&conf->empty_inactive_list_nr))
5087                 return 1;
5088
5089         return 0;
5090 }
5091
5092 static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
5093 {
5094         struct r5conf *conf = mddev->private;
5095         sector_t sector = bio->bi_iter.bi_sector;
5096         unsigned int chunk_sectors;
5097         unsigned int bio_sectors = bio_sectors(bio);
5098
5099         WARN_ON_ONCE(bio->bi_partno);
5100
5101         chunk_sectors = min(conf->chunk_sectors, conf->prev_chunk_sectors);
5102         return  chunk_sectors >=
5103                 ((sector & (chunk_sectors - 1)) + bio_sectors);
5104 }
5105
5106 /*
5107  *  add bio to the retry LIFO  ( in O(1) ... we are in interrupt )
5108  *  later sampled by raid5d.
5109  */
5110 static void add_bio_to_retry(struct bio *bi,struct r5conf *conf)
5111 {
5112         unsigned long flags;
5113
5114         spin_lock_irqsave(&conf->device_lock, flags);
5115
5116         bi->bi_next = conf->retry_read_aligned_list;
5117         conf->retry_read_aligned_list = bi;
5118
5119         spin_unlock_irqrestore(&conf->device_lock, flags);
5120         md_wakeup_thread(conf->mddev->thread);
5121 }
5122
5123 static struct bio *remove_bio_from_retry(struct r5conf *conf,
5124                                          unsigned int *offset)
5125 {
5126         struct bio *bi;
5127
5128         bi = conf->retry_read_aligned;
5129         if (bi) {
5130                 *offset = conf->retry_read_offset;
5131                 conf->retry_read_aligned = NULL;
5132                 return bi;
5133         }
5134         bi = conf->retry_read_aligned_list;
5135         if(bi) {
5136                 conf->retry_read_aligned_list = bi->bi_next;
5137                 bi->bi_next = NULL;
5138                 *offset = 0;
5139         }
5140
5141         return bi;
5142 }
5143
5144 /*
5145  *  The "raid5_align_endio" should check if the read succeeded and if it
5146  *  did, call bio_endio on the original bio (having bio_put the new bio
5147  *  first).
5148  *  If the read failed..
5149  */
5150 static void raid5_align_endio(struct bio *bi)
5151 {
5152         struct bio* raid_bi  = bi->bi_private;
5153         struct mddev *mddev;
5154         struct r5conf *conf;
5155         struct md_rdev *rdev;
5156         blk_status_t error = bi->bi_status;
5157
5158         bio_put(bi);
5159
5160         rdev = (void*)raid_bi->bi_next;
5161         raid_bi->bi_next = NULL;
5162         mddev = rdev->mddev;
5163         conf = mddev->private;
5164
5165         rdev_dec_pending(rdev, conf->mddev);
5166
5167         if (!error) {
5168                 bio_endio(raid_bi);
5169                 if (atomic_dec_and_test(&conf->active_aligned_reads))
5170                         wake_up(&conf->wait_for_quiescent);
5171                 return;
5172         }
5173
5174         pr_debug("raid5_align_endio : io error...handing IO for a retry\n");
5175
5176         add_bio_to_retry(raid_bi, conf);
5177 }
5178
5179 static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio)
5180 {
5181         struct r5conf *conf = mddev->private;
5182         int dd_idx;
5183         struct bio* align_bi;
5184         struct md_rdev *rdev;
5185         sector_t end_sector;
5186
5187         if (!in_chunk_boundary(mddev, raid_bio)) {
5188                 pr_debug("%s: non aligned\n", __func__);
5189                 return 0;
5190         }
5191         /*
5192          * use bio_clone_fast to make a copy of the bio
5193          */
5194         align_bi = bio_clone_fast(raid_bio, GFP_NOIO, mddev->bio_set);
5195         if (!align_bi)
5196                 return 0;
5197         /*
5198          *   set bi_end_io to a new function, and set bi_private to the
5199          *     original bio.
5200          */
5201         align_bi->bi_end_io  = raid5_align_endio;
5202         align_bi->bi_private = raid_bio;
5203         /*
5204          *      compute position
5205          */
5206         align_bi->bi_iter.bi_sector =
5207                 raid5_compute_sector(conf, raid_bio->bi_iter.bi_sector,
5208                                      0, &dd_idx, NULL);
5209
5210         end_sector = bio_end_sector(align_bi);
5211         rcu_read_lock();
5212         rdev = rcu_dereference(conf->disks[dd_idx].replacement);
5213         if (!rdev || test_bit(Faulty, &rdev->flags) ||
5214             rdev->recovery_offset < end_sector) {
5215                 rdev = rcu_dereference(conf->disks[dd_idx].rdev);
5216                 if (rdev &&
5217                     (test_bit(Faulty, &rdev->flags) ||
5218                     !(test_bit(In_sync, &rdev->flags) ||
5219                       rdev->recovery_offset >= end_sector)))
5220                         rdev = NULL;
5221         }
5222
5223         if (r5c_big_stripe_cached(conf, align_bi->bi_iter.bi_sector)) {
5224                 rcu_read_unlock();
5225                 bio_put(align_bi);
5226                 return 0;
5227         }
5228
5229         if (rdev) {
5230                 sector_t first_bad;
5231                 int bad_sectors;
5232
5233                 atomic_inc(&rdev->nr_pending);
5234                 rcu_read_unlock();
5235                 raid_bio->bi_next = (void*)rdev;
5236                 bio_set_dev(align_bi, rdev->bdev);
5237                 bio_clear_flag(align_bi, BIO_SEG_VALID);
5238
5239                 if (is_badblock(rdev, align_bi->bi_iter.bi_sector,
5240                                 bio_sectors(align_bi),
5241                                 &first_bad, &bad_sectors)) {
5242                         bio_put(align_bi);
5243                         rdev_dec_pending(rdev, mddev);
5244                         return 0;
5245                 }
5246
5247                 /* No reshape active, so we can trust rdev->data_offset */
5248                 align_bi->bi_iter.bi_sector += rdev->data_offset;
5249
5250                 spin_lock_irq(&conf->device_lock);
5251                 wait_event_lock_irq(conf->wait_for_quiescent,
5252                                     conf->quiesce == 0,
5253                                     conf->device_lock);
5254                 atomic_inc(&conf->active_aligned_reads);
5255                 spin_unlock_irq(&conf->device_lock);
5256
5257                 if (mddev->gendisk)
5258                         trace_block_bio_remap(align_bi->bi_disk->queue,
5259                                               align_bi, disk_devt(mddev->gendisk),
5260                                               raid_bio->bi_iter.bi_sector);
5261                 generic_make_request(align_bi);
5262                 return 1;
5263         } else {
5264                 rcu_read_unlock();
5265                 bio_put(align_bi);
5266                 return 0;
5267         }
5268 }
5269
5270 static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio)
5271 {
5272         struct bio *split;
5273         sector_t sector = raid_bio->bi_iter.bi_sector;
5274         unsigned chunk_sects = mddev->chunk_sectors;
5275         unsigned sectors = chunk_sects - (sector & (chunk_sects-1));
5276
5277         if (sectors < bio_sectors(raid_bio)) {
5278                 struct r5conf *conf = mddev->private;
5279                 split = bio_split(raid_bio, sectors, GFP_NOIO, conf->bio_split);
5280                 bio_chain(split, raid_bio);
5281                 generic_make_request(raid_bio);
5282                 raid_bio = split;
5283         }
5284
5285         if (!raid5_read_one_chunk(mddev, raid_bio))
5286                 return raid_bio;
5287
5288         return NULL;
5289 }
5290
5291 /* __get_priority_stripe - get the next stripe to process
5292  *
5293  * Full stripe writes are allowed to pass preread active stripes up until
5294  * the bypass_threshold is exceeded.  In general the bypass_count
5295  * increments when the handle_list is handled before the hold_list; however, it
5296  * will not be incremented when STRIPE_IO_STARTED is sampled set signifying a
5297  * stripe with in flight i/o.  The bypass_count will be reset when the
5298  * head of the hold_list has changed, i.e. the head was promoted to the
5299  * handle_list.
5300  */
5301 static struct stripe_head *__get_priority_stripe(struct r5conf *conf, int group)
5302 {
5303         struct stripe_head *sh, *tmp;
5304         struct list_head *handle_list = NULL;
5305         struct r5worker_group *wg;
5306         bool second_try = !r5c_is_writeback(conf->log) &&
5307                 !r5l_log_disk_error(conf);
5308         bool try_loprio = test_bit(R5C_LOG_TIGHT, &conf->cache_state) ||
5309                 r5l_log_disk_error(conf);
5310
5311 again:
5312         wg = NULL;
5313         sh = NULL;
5314         if (conf->worker_cnt_per_group == 0) {
5315                 handle_list = try_loprio ? &conf->loprio_list :
5316                                         &conf->handle_list;
5317         } else if (group != ANY_GROUP) {
5318                 handle_list = try_loprio ? &conf->worker_groups[group].loprio_list :
5319                                 &conf->worker_groups[group].handle_list;
5320                 wg = &conf->worker_groups[group];
5321         } else {
5322                 int i;
5323                 for (i = 0; i < conf->group_cnt; i++) {
5324                         handle_list = try_loprio ? &conf->worker_groups[i].loprio_list :
5325                                 &conf->worker_groups[i].handle_list;
5326                         wg = &conf->worker_groups[i];
5327                         if (!list_empty(handle_list))
5328                                 break;
5329                 }
5330         }
5331
5332         pr_debug("%s: handle: %s hold: %s full_writes: %d bypass_count: %d\n",
5333                   __func__,
5334                   list_empty(handle_list) ? "empty" : "busy",
5335                   list_empty(&conf->hold_list) ? "empty" : "busy",
5336                   atomic_read(&conf->pending_full_writes), conf->bypass_count);
5337
5338         if (!list_empty(handle_list)) {
5339                 sh = list_entry(handle_list->next, typeof(*sh), lru);
5340
5341                 if (list_empty(&conf->hold_list))
5342                         conf->bypass_count = 0;
5343                 else if (!test_bit(STRIPE_IO_STARTED, &sh->state)) {
5344                         if (conf->hold_list.next == conf->last_hold)
5345                                 conf->bypass_count++;
5346                         else {
5347                                 conf->last_hold = conf->hold_list.next;
5348                                 conf->bypass_count -= conf->bypass_threshold;
5349                                 if (conf->bypass_count < 0)
5350                                         conf->bypass_count = 0;
5351                         }
5352                 }
5353         } else if (!list_empty(&conf->hold_list) &&
5354                    ((conf->bypass_threshold &&
5355                      conf->bypass_count > conf->bypass_threshold) ||
5356                     atomic_read(&conf->pending_full_writes) == 0)) {
5357
5358                 list_for_each_entry(tmp, &conf->hold_list,  lru) {
5359                         if (conf->worker_cnt_per_group == 0 ||
5360                             group == ANY_GROUP ||
5361                             !cpu_online(tmp->cpu) ||
5362                             cpu_to_group(tmp->cpu) == group) {
5363                                 sh = tmp;
5364                                 break;
5365                         }
5366                 }
5367
5368                 if (sh) {
5369                         conf->bypass_count -= conf->bypass_threshold;
5370                         if (conf->bypass_count < 0)
5371                                 conf->bypass_count = 0;
5372                 }
5373                 wg = NULL;
5374         }
5375
5376         if (!sh) {
5377                 if (second_try)
5378                         return NULL;
5379                 second_try = true;
5380                 try_loprio = !try_loprio;
5381                 goto again;
5382         }
5383
5384         if (wg) {
5385                 wg->stripes_cnt--;
5386                 sh->group = NULL;
5387         }
5388         list_del_init(&sh->lru);
5389         BUG_ON(atomic_inc_return(&sh->count) != 1);
5390         return sh;
5391 }
5392
5393 struct raid5_plug_cb {
5394         struct blk_plug_cb      cb;
5395         struct list_head        list;
5396         struct list_head        temp_inactive_list[NR_STRIPE_HASH_LOCKS];
5397 };
5398
5399 static void raid5_unplug(struct blk_plug_cb *blk_cb, bool from_schedule)
5400 {
5401         struct raid5_plug_cb *cb = container_of(
5402                 blk_cb, struct raid5_plug_cb, cb);
5403         struct stripe_head *sh;
5404         struct mddev *mddev = cb->cb.data;
5405         struct r5conf *conf = mddev->private;
5406         int cnt = 0;
5407         int hash;
5408
5409         if (cb->list.next && !list_empty(&cb->list)) {
5410                 spin_lock_irq(&conf->device_lock);
5411                 while (!list_empty(&cb->list)) {
5412                         sh = list_first_entry(&cb->list, struct stripe_head, lru);
5413                         list_del_init(&sh->lru);
5414                         /*
5415                          * avoid race release_stripe_plug() sees
5416                          * STRIPE_ON_UNPLUG_LIST clear but the stripe
5417                          * is still in our list
5418                          */
5419                         smp_mb__before_atomic();
5420                         clear_bit(STRIPE_ON_UNPLUG_LIST, &sh->state);
5421                         /*
5422                          * STRIPE_ON_RELEASE_LIST could be set here. In that
5423                          * case, the count is always > 1 here
5424                          */
5425                         hash = sh->hash_lock_index;
5426                         __release_stripe(conf, sh, &cb->temp_inactive_list[hash]);
5427                         cnt++;
5428                 }
5429                 spin_unlock_irq(&conf->device_lock);
5430         }
5431         release_inactive_stripe_list(conf, cb->temp_inactive_list,
5432                                      NR_STRIPE_HASH_LOCKS);
5433         if (mddev->queue)
5434                 trace_block_unplug(mddev->queue, cnt, !from_schedule);
5435         kfree(cb);
5436 }
5437
5438 static void release_stripe_plug(struct mddev *mddev,
5439                                 struct stripe_head *sh)
5440 {
5441         struct blk_plug_cb *blk_cb = blk_check_plugged(
5442                 raid5_unplug, mddev,
5443                 sizeof(struct raid5_plug_cb));
5444         struct raid5_plug_cb *cb;
5445
5446         if (!blk_cb) {
5447                 raid5_release_stripe(sh);
5448                 return;
5449         }
5450
5451         cb = container_of(blk_cb, struct raid5_plug_cb, cb);
5452
5453         if (cb->list.next == NULL) {
5454                 int i;
5455                 INIT_LIST_HEAD(&cb->list);
5456                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
5457                         INIT_LIST_HEAD(cb->temp_inactive_list + i);
5458         }
5459
5460         if (!test_and_set_bit(STRIPE_ON_UNPLUG_LIST, &sh->state))
5461                 list_add_tail(&sh->lru, &cb->list);
5462         else
5463                 raid5_release_stripe(sh);
5464 }
5465
5466 static void make_discard_request(struct mddev *mddev, struct bio *bi)
5467 {
5468         struct r5conf *conf = mddev->private;
5469         sector_t logical_sector, last_sector;
5470         struct stripe_head *sh;
5471         int stripe_sectors;
5472
5473         if (mddev->reshape_position != MaxSector)
5474                 /* Skip discard while reshape is happening */
5475                 return;
5476
5477         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5478         last_sector = bi->bi_iter.bi_sector + (bi->bi_iter.bi_size>>9);
5479
5480         bi->bi_next = NULL;
5481
5482         stripe_sectors = conf->chunk_sectors *
5483                 (conf->raid_disks - conf->max_degraded);
5484         logical_sector = DIV_ROUND_UP_SECTOR_T(logical_sector,
5485                                                stripe_sectors);
5486         sector_div(last_sector, stripe_sectors);
5487
5488         logical_sector *= conf->chunk_sectors;
5489         last_sector *= conf->chunk_sectors;
5490
5491         for (; logical_sector < last_sector;
5492              logical_sector += STRIPE_SECTORS) {
5493                 DEFINE_WAIT(w);
5494                 int d;
5495         again:
5496                 sh = raid5_get_active_stripe(conf, logical_sector, 0, 0, 0);
5497                 prepare_to_wait(&conf->wait_for_overlap, &w,
5498                                 TASK_UNINTERRUPTIBLE);
5499                 set_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5500                 if (test_bit(STRIPE_SYNCING, &sh->state)) {
5501                         raid5_release_stripe(sh);
5502                         schedule();
5503                         goto again;
5504                 }
5505                 clear_bit(R5_Overlap, &sh->dev[sh->pd_idx].flags);
5506                 spin_lock_irq(&sh->stripe_lock);
5507                 for (d = 0; d < conf->raid_disks; d++) {
5508                         if (d == sh->pd_idx || d == sh->qd_idx)
5509                                 continue;
5510                         if (sh->dev[d].towrite || sh->dev[d].toread) {
5511                                 set_bit(R5_Overlap, &sh->dev[d].flags);
5512                                 spin_unlock_irq(&sh->stripe_lock);
5513                                 raid5_release_stripe(sh);
5514                                 schedule();
5515                                 goto again;
5516                         }
5517                 }
5518                 set_bit(STRIPE_DISCARD, &sh->state);
5519                 finish_wait(&conf->wait_for_overlap, &w);
5520                 sh->overwrite_disks = 0;
5521                 for (d = 0; d < conf->raid_disks; d++) {
5522                         if (d == sh->pd_idx || d == sh->qd_idx)
5523                                 continue;
5524                         sh->dev[d].towrite = bi;
5525                         set_bit(R5_OVERWRITE, &sh->dev[d].flags);
5526                         bio_inc_remaining(bi);
5527                         md_write_inc(mddev, bi);
5528                         sh->overwrite_disks++;
5529                 }
5530                 spin_unlock_irq(&sh->stripe_lock);
5531                 if (conf->mddev->bitmap) {
5532                         for (d = 0;
5533                              d < conf->raid_disks - conf->max_degraded;
5534                              d++)
5535                                 bitmap_startwrite(mddev->bitmap,
5536                                                   sh->sector,
5537                                                   STRIPE_SECTORS,
5538                                                   0);
5539                         sh->bm_seq = conf->seq_flush + 1;
5540                         set_bit(STRIPE_BIT_DELAY, &sh->state);
5541                 }
5542
5543                 set_bit(STRIPE_HANDLE, &sh->state);
5544                 clear_bit(STRIPE_DELAYED, &sh->state);
5545                 if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5546                         atomic_inc(&conf->preread_active_stripes);
5547                 release_stripe_plug(mddev, sh);
5548         }
5549
5550         bio_endio(bi);
5551 }
5552
5553 static bool raid5_make_request(struct mddev *mddev, struct bio * bi)
5554 {
5555         struct r5conf *conf = mddev->private;
5556         int dd_idx;
5557         sector_t new_sector;
5558         sector_t logical_sector, last_sector;
5559         struct stripe_head *sh;
5560         const int rw = bio_data_dir(bi);
5561         DEFINE_WAIT(w);
5562         bool do_prepare;
5563         bool do_flush = false;
5564
5565         if (unlikely(bi->bi_opf & REQ_PREFLUSH)) {
5566                 int ret = log_handle_flush_request(conf, bi);
5567
5568                 if (ret == 0)
5569                         return true;
5570                 if (ret == -ENODEV) {
5571                         md_flush_request(mddev, bi);
5572                         return true;
5573                 }
5574                 /* ret == -EAGAIN, fallback */
5575                 /*
5576                  * if r5l_handle_flush_request() didn't clear REQ_PREFLUSH,
5577                  * we need to flush journal device
5578                  */
5579                 do_flush = bi->bi_opf & REQ_PREFLUSH;
5580         }
5581
5582         if (!md_write_start(mddev, bi))
5583                 return false;
5584         /*
5585          * If array is degraded, better not do chunk aligned read because
5586          * later we might have to read it again in order to reconstruct
5587          * data on failed drives.
5588          */
5589         if (rw == READ && mddev->degraded == 0 &&
5590             mddev->reshape_position == MaxSector) {
5591                 bi = chunk_aligned_read(mddev, bi);
5592                 if (!bi)
5593                         return true;
5594         }
5595
5596         if (unlikely(bio_op(bi) == REQ_OP_DISCARD)) {
5597                 make_discard_request(mddev, bi);
5598                 md_write_end(mddev);
5599                 return true;
5600         }
5601
5602         logical_sector = bi->bi_iter.bi_sector & ~((sector_t)STRIPE_SECTORS-1);
5603         last_sector = bio_end_sector(bi);
5604         bi->bi_next = NULL;
5605
5606         prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE);
5607         for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) {
5608                 int previous;
5609                 int seq;
5610
5611                 do_prepare = false;
5612         retry:
5613                 seq = read_seqcount_begin(&conf->gen_lock);
5614                 previous = 0;
5615                 if (do_prepare)
5616                         prepare_to_wait(&conf->wait_for_overlap, &w,
5617                                 TASK_UNINTERRUPTIBLE);
5618                 if (unlikely(conf->reshape_progress != MaxSector)) {
5619                         /* spinlock is needed as reshape_progress may be
5620                          * 64bit on a 32bit platform, and so it might be
5621                          * possible to see a half-updated value
5622                          * Of course reshape_progress could change after
5623                          * the lock is dropped, so once we get a reference
5624                          * to the stripe that we think it is, we will have
5625                          * to check again.
5626                          */
5627                         spin_lock_irq(&conf->device_lock);
5628                         if (mddev->reshape_backwards
5629                             ? logical_sector < conf->reshape_progress
5630                             : logical_sector >= conf->reshape_progress) {
5631                                 previous = 1;
5632                         } else {
5633                                 if (mddev->reshape_backwards
5634                                     ? logical_sector < conf->reshape_safe
5635                                     : logical_sector >= conf->reshape_safe) {
5636                                         spin_unlock_irq(&conf->device_lock);
5637                                         schedule();
5638                                         do_prepare = true;
5639                                         goto retry;
5640                                 }
5641                         }
5642                         spin_unlock_irq(&conf->device_lock);
5643                 }
5644
5645                 new_sector = raid5_compute_sector(conf, logical_sector,
5646                                                   previous,
5647                                                   &dd_idx, NULL);
5648                 pr_debug("raid456: raid5_make_request, sector %llu logical %llu\n",
5649                         (unsigned long long)new_sector,
5650                         (unsigned long long)logical_sector);
5651
5652                 sh = raid5_get_active_stripe(conf, new_sector, previous,
5653                                        (bi->bi_opf & REQ_RAHEAD), 0);
5654                 if (sh) {
5655                         if (unlikely(previous)) {
5656                                 /* expansion might have moved on while waiting for a
5657                                  * stripe, so we must do the range check again.
5658                                  * Expansion could still move past after this
5659                                  * test, but as we are holding a reference to
5660                                  * 'sh', we know that if that happens,
5661                                  *  STRIPE_EXPANDING will get set and the expansion
5662                                  * won't proceed until we finish with the stripe.
5663                                  */
5664                                 int must_retry = 0;
5665                                 spin_lock_irq(&conf->device_lock);
5666                                 if (mddev->reshape_backwards
5667                                     ? logical_sector >= conf->reshape_progress
5668                                     : logical_sector < conf->reshape_progress)
5669                                         /* mismatch, need to try again */
5670                                         must_retry = 1;
5671                                 spin_unlock_irq(&conf->device_lock);
5672                                 if (must_retry) {
5673                                         raid5_release_stripe(sh);
5674                                         schedule();
5675                                         do_prepare = true;
5676                                         goto retry;
5677                                 }
5678                         }
5679                         if (read_seqcount_retry(&conf->gen_lock, seq)) {
5680                                 /* Might have got the wrong stripe_head
5681                                  * by accident
5682                                  */
5683                                 raid5_release_stripe(sh);
5684                                 goto retry;
5685                         }
5686
5687                         if (test_bit(STRIPE_EXPANDING, &sh->state) ||
5688                             !add_stripe_bio(sh, bi, dd_idx, rw, previous)) {
5689                                 /* Stripe is busy expanding or
5690                                  * add failed due to overlap.  Flush everything
5691                                  * and wait a while
5692                                  */
5693                                 md_wakeup_thread(mddev->thread);
5694                                 raid5_release_stripe(sh);
5695                                 schedule();
5696                                 do_prepare = true;
5697                                 goto retry;
5698                         }
5699                         if (do_flush) {
5700                                 set_bit(STRIPE_R5C_PREFLUSH, &sh->state);
5701                                 /* we only need flush for one stripe */
5702                                 do_flush = false;
5703                         }
5704
5705                         set_bit(STRIPE_HANDLE, &sh->state);
5706                         clear_bit(STRIPE_DELAYED, &sh->state);
5707                         if ((!sh->batch_head || sh == sh->batch_head) &&
5708                             (bi->bi_opf & REQ_SYNC) &&
5709                             !test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
5710                                 atomic_inc(&conf->preread_active_stripes);
5711                         release_stripe_plug(mddev, sh);
5712                 } else {
5713                         /* cannot get stripe for read-ahead, just give-up */
5714                         bi->bi_status = BLK_STS_IOERR;
5715                         break;
5716                 }
5717         }
5718         finish_wait(&conf->wait_for_overlap, &w);
5719
5720         if (rw == WRITE)
5721                 md_write_end(mddev);
5722         bio_endio(bi);
5723         return true;
5724 }
5725
5726 static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
5727
5728 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, int *skipped)
5729 {
5730         /* reshaping is quite different to recovery/resync so it is
5731          * handled quite separately ... here.
5732          *
5733          * On each call to sync_request, we gather one chunk worth of
5734          * destination stripes and flag them as expanding.
5735          * Then we find all the source stripes and request reads.
5736          * As the reads complete, handle_stripe will copy the data
5737          * into the destination stripe and release that stripe.
5738          */
5739         struct r5conf *conf = mddev->private;
5740         struct stripe_head *sh;
5741         struct md_rdev *rdev;
5742         sector_t first_sector, last_sector;
5743         int raid_disks = conf->previous_raid_disks;
5744         int data_disks = raid_disks - conf->max_degraded;
5745         int new_data_disks = conf->raid_disks - conf->max_degraded;
5746         int i;
5747         int dd_idx;
5748         sector_t writepos, readpos, safepos;
5749         sector_t stripe_addr;
5750         int reshape_sectors;
5751         struct list_head stripes;
5752         sector_t retn;
5753
5754         if (sector_nr == 0) {
5755                 /* If restarting in the middle, skip the initial sectors */
5756                 if (mddev->reshape_backwards &&
5757                     conf->reshape_progress < raid5_size(mddev, 0, 0)) {
5758                         sector_nr = raid5_size(mddev, 0, 0)
5759                                 - conf->reshape_progress;
5760                 } else if (mddev->reshape_backwards &&
5761                            conf->reshape_progress == MaxSector) {
5762                         /* shouldn't happen, but just in case, finish up.*/
5763                         sector_nr = MaxSector;
5764                 } else if (!mddev->reshape_backwards &&
5765                            conf->reshape_progress > 0)
5766                         sector_nr = conf->reshape_progress;
5767                 sector_div(sector_nr, new_data_disks);
5768                 if (sector_nr) {
5769                         mddev->curr_resync_completed = sector_nr;
5770                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5771                         *skipped = 1;
5772                         retn = sector_nr;
5773                         goto finish;
5774                 }
5775         }
5776
5777         /* We need to process a full chunk at a time.
5778          * If old and new chunk sizes differ, we need to process the
5779          * largest of these
5780          */
5781
5782         reshape_sectors = max(conf->chunk_sectors, conf->prev_chunk_sectors);
5783
5784         /* We update the metadata at least every 10 seconds, or when
5785          * the data about to be copied would over-write the source of
5786          * the data at the front of the range.  i.e. one new_stripe
5787          * along from reshape_progress new_maps to after where
5788          * reshape_safe old_maps to
5789          */
5790         writepos = conf->reshape_progress;
5791         sector_div(writepos, new_data_disks);
5792         readpos = conf->reshape_progress;
5793         sector_div(readpos, data_disks);
5794         safepos = conf->reshape_safe;
5795         sector_div(safepos, data_disks);
5796         if (mddev->reshape_backwards) {
5797                 BUG_ON(writepos < reshape_sectors);
5798                 writepos -= reshape_sectors;
5799                 readpos += reshape_sectors;
5800                 safepos += reshape_sectors;
5801         } else {
5802                 writepos += reshape_sectors;
5803                 /* readpos and safepos are worst-case calculations.
5804                  * A negative number is overly pessimistic, and causes
5805                  * obvious problems for unsigned storage.  So clip to 0.
5806                  */
5807                 readpos -= min_t(sector_t, reshape_sectors, readpos);
5808                 safepos -= min_t(sector_t, reshape_sectors, safepos);
5809         }
5810
5811         /* Having calculated the 'writepos' possibly use it
5812          * to set 'stripe_addr' which is where we will write to.
5813          */
5814         if (mddev->reshape_backwards) {
5815                 BUG_ON(conf->reshape_progress == 0);
5816                 stripe_addr = writepos;
5817                 BUG_ON((mddev->dev_sectors &
5818                         ~((sector_t)reshape_sectors - 1))
5819                        - reshape_sectors - stripe_addr
5820                        != sector_nr);
5821         } else {
5822                 BUG_ON(writepos != sector_nr + reshape_sectors);
5823                 stripe_addr = sector_nr;
5824         }
5825
5826         /* 'writepos' is the most advanced device address we might write.
5827          * 'readpos' is the least advanced device address we might read.
5828          * 'safepos' is the least address recorded in the metadata as having
5829          *     been reshaped.
5830          * If there is a min_offset_diff, these are adjusted either by
5831          * increasing the safepos/readpos if diff is negative, or
5832          * increasing writepos if diff is positive.
5833          * If 'readpos' is then behind 'writepos', there is no way that we can
5834          * ensure safety in the face of a crash - that must be done by userspace
5835          * making a backup of the data.  So in that case there is no particular
5836          * rush to update metadata.
5837          * Otherwise if 'safepos' is behind 'writepos', then we really need to
5838          * update the metadata to advance 'safepos' to match 'readpos' so that
5839          * we can be safe in the event of a crash.
5840          * So we insist on updating metadata if safepos is behind writepos and
5841          * readpos is beyond writepos.
5842          * In any case, update the metadata every 10 seconds.
5843          * Maybe that number should be configurable, but I'm not sure it is
5844          * worth it.... maybe it could be a multiple of safemode_delay???
5845          */
5846         if (conf->min_offset_diff < 0) {
5847                 safepos += -conf->min_offset_diff;
5848                 readpos += -conf->min_offset_diff;
5849         } else
5850                 writepos += conf->min_offset_diff;
5851
5852         if ((mddev->reshape_backwards
5853              ? (safepos > writepos && readpos < writepos)
5854              : (safepos < writepos && readpos > writepos)) ||
5855             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
5856                 /* Cannot proceed until we've updated the superblock... */
5857                 wait_event(conf->wait_for_overlap,
5858                            atomic_read(&conf->reshape_stripes)==0
5859                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5860                 if (atomic_read(&conf->reshape_stripes) != 0)
5861                         return 0;
5862                 mddev->reshape_position = conf->reshape_progress;
5863                 mddev->curr_resync_completed = sector_nr;
5864                 if (!mddev->reshape_backwards)
5865                         /* Can update recovery_offset */
5866                         rdev_for_each(rdev, mddev)
5867                                 if (rdev->raid_disk >= 0 &&
5868                                     !test_bit(Journal, &rdev->flags) &&
5869                                     !test_bit(In_sync, &rdev->flags) &&
5870                                     rdev->recovery_offset < sector_nr)
5871                                         rdev->recovery_offset = sector_nr;
5872
5873                 conf->reshape_checkpoint = jiffies;
5874                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5875                 md_wakeup_thread(mddev->thread);
5876                 wait_event(mddev->sb_wait, mddev->sb_flags == 0 ||
5877                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5878                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5879                         return 0;
5880                 spin_lock_irq(&conf->device_lock);
5881                 conf->reshape_safe = mddev->reshape_position;
5882                 spin_unlock_irq(&conf->device_lock);
5883                 wake_up(&conf->wait_for_overlap);
5884                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5885         }
5886
5887         INIT_LIST_HEAD(&stripes);
5888         for (i = 0; i < reshape_sectors; i += STRIPE_SECTORS) {
5889                 int j;
5890                 int skipped_disk = 0;
5891                 sh = raid5_get_active_stripe(conf, stripe_addr+i, 0, 0, 1);
5892                 set_bit(STRIPE_EXPANDING, &sh->state);
5893                 atomic_inc(&conf->reshape_stripes);
5894                 /* If any of this stripe is beyond the end of the old
5895                  * array, then we need to zero those blocks
5896                  */
5897                 for (j=sh->disks; j--;) {
5898                         sector_t s;
5899                         if (j == sh->pd_idx)
5900                                 continue;
5901                         if (conf->level == 6 &&
5902                             j == sh->qd_idx)
5903                                 continue;
5904                         s = raid5_compute_blocknr(sh, j, 0);
5905                         if (s < raid5_size(mddev, 0, 0)) {
5906                                 skipped_disk = 1;
5907                                 continue;
5908                         }
5909                         memset(page_address(sh->dev[j].page), 0, STRIPE_SIZE);
5910                         set_bit(R5_Expanded, &sh->dev[j].flags);
5911                         set_bit(R5_UPTODATE, &sh->dev[j].flags);
5912                 }
5913                 if (!skipped_disk) {
5914                         set_bit(STRIPE_EXPAND_READY, &sh->state);
5915                         set_bit(STRIPE_HANDLE, &sh->state);
5916                 }
5917                 list_add(&sh->lru, &stripes);
5918         }
5919         spin_lock_irq(&conf->device_lock);
5920         if (mddev->reshape_backwards)
5921                 conf->reshape_progress -= reshape_sectors * new_data_disks;
5922         else
5923                 conf->reshape_progress += reshape_sectors * new_data_disks;
5924         spin_unlock_irq(&conf->device_lock);
5925         /* Ok, those stripe are ready. We can start scheduling
5926          * reads on the source stripes.
5927          * The source stripes are determined by mapping the first and last
5928          * block on the destination stripes.
5929          */
5930         first_sector =
5931                 raid5_compute_sector(conf, stripe_addr*(new_data_disks),
5932                                      1, &dd_idx, NULL);
5933         last_sector =
5934                 raid5_compute_sector(conf, ((stripe_addr+reshape_sectors)
5935                                             * new_data_disks - 1),
5936                                      1, &dd_idx, NULL);
5937         if (last_sector >= mddev->dev_sectors)
5938                 last_sector = mddev->dev_sectors - 1;
5939         while (first_sector <= last_sector) {
5940                 sh = raid5_get_active_stripe(conf, first_sector, 1, 0, 1);
5941                 set_bit(STRIPE_EXPAND_SOURCE, &sh->state);
5942                 set_bit(STRIPE_HANDLE, &sh->state);
5943                 raid5_release_stripe(sh);
5944                 first_sector += STRIPE_SECTORS;
5945         }
5946         /* Now that the sources are clearly marked, we can release
5947          * the destination stripes
5948          */
5949         while (!list_empty(&stripes)) {
5950                 sh = list_entry(stripes.next, struct stripe_head, lru);
5951                 list_del_init(&sh->lru);
5952                 raid5_release_stripe(sh);
5953         }
5954         /* If this takes us to the resync_max point where we have to pause,
5955          * then we need to write out the superblock.
5956          */
5957         sector_nr += reshape_sectors;
5958         retn = reshape_sectors;
5959 finish:
5960         if (mddev->curr_resync_completed > mddev->resync_max ||
5961             (sector_nr - mddev->curr_resync_completed) * 2
5962             >= mddev->resync_max - mddev->curr_resync_completed) {
5963                 /* Cannot proceed until we've updated the superblock... */
5964                 wait_event(conf->wait_for_overlap,
5965                            atomic_read(&conf->reshape_stripes) == 0
5966                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5967                 if (atomic_read(&conf->reshape_stripes) != 0)
5968                         goto ret;
5969                 mddev->reshape_position = conf->reshape_progress;
5970                 mddev->curr_resync_completed = sector_nr;
5971                 if (!mddev->reshape_backwards)
5972                         /* Can update recovery_offset */
5973                         rdev_for_each(rdev, mddev)
5974                                 if (rdev->raid_disk >= 0 &&
5975                                     !test_bit(Journal, &rdev->flags) &&
5976                                     !test_bit(In_sync, &rdev->flags) &&
5977                                     rdev->recovery_offset < sector_nr)
5978                                         rdev->recovery_offset = sector_nr;
5979                 conf->reshape_checkpoint = jiffies;
5980                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
5981                 md_wakeup_thread(mddev->thread);
5982                 wait_event(mddev->sb_wait,
5983                            !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)
5984                            || test_bit(MD_RECOVERY_INTR, &mddev->recovery));
5985                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
5986                         goto ret;
5987                 spin_lock_irq(&conf->device_lock);
5988                 conf->reshape_safe = mddev->reshape_position;
5989                 spin_unlock_irq(&conf->device_lock);
5990                 wake_up(&conf->wait_for_overlap);
5991                 sysfs_notify(&mddev->kobj, NULL, "sync_completed");
5992         }
5993 ret:
5994         return retn;
5995 }
5996
5997 static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_nr,
5998                                           int *skipped)
5999 {
6000         struct r5conf *conf = mddev->private;
6001         struct stripe_head *sh;
6002         sector_t max_sector = mddev->dev_sectors;
6003         sector_t sync_blocks;
6004         int still_degraded = 0;
6005         int i;
6006
6007         if (sector_nr >= max_sector) {
6008                 /* just being told to finish up .. nothing much to do */
6009
6010                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
6011                         end_reshape(conf);
6012                         return 0;
6013                 }
6014
6015                 if (mddev->curr_resync < max_sector) /* aborted */
6016                         bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
6017                                         &sync_blocks, 1);
6018                 else /* completed sync */
6019                         conf->fullsync = 0;
6020                 bitmap_close_sync(mddev->bitmap);
6021
6022                 return 0;
6023         }
6024
6025         /* Allow raid5_quiesce to complete */
6026         wait_event(conf->wait_for_overlap, conf->quiesce != 2);
6027
6028         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
6029                 return reshape_request(mddev, sector_nr, skipped);
6030
6031         /* No need to check resync_max as we never do more than one
6032          * stripe, and as resync_max will always be on a chunk boundary,
6033          * if the check in md_do_sync didn't fire, there is no chance
6034          * of overstepping resync_max here
6035          */
6036
6037         /* if there is too many failed drives and we are trying
6038          * to resync, then assert that we are finished, because there is
6039          * nothing we can do.
6040          */
6041         if (mddev->degraded >= conf->max_degraded &&
6042             test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
6043                 sector_t rv = mddev->dev_sectors - sector_nr;
6044                 *skipped = 1;
6045                 return rv;
6046         }
6047         if (!test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
6048             !conf->fullsync &&
6049             !bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, 1) &&
6050             sync_blocks >= STRIPE_SECTORS) {
6051                 /* we can skip this block, and probably more */
6052                 sync_blocks /= STRIPE_SECTORS;
6053                 *skipped = 1;
6054                 return sync_blocks * STRIPE_SECTORS; /* keep things rounded to whole stripes */
6055         }
6056
6057         bitmap_cond_end_sync(mddev->bitmap, sector_nr, false);
6058
6059         sh = raid5_get_active_stripe(conf, sector_nr, 0, 1, 0);
6060         if (sh == NULL) {
6061                 sh = raid5_get_active_stripe(conf, sector_nr, 0, 0, 0);
6062                 /* make sure we don't swamp the stripe cache if someone else
6063                  * is trying to get access
6064                  */
6065                 schedule_timeout_uninterruptible(1);
6066         }
6067         /* Need to check if array will still be degraded after recovery/resync
6068          * Note in case of > 1 drive failures it's possible we're rebuilding
6069          * one drive while leaving another faulty drive in array.
6070          */
6071         rcu_read_lock();
6072         for (i = 0; i < conf->raid_disks; i++) {
6073                 struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev);
6074
6075                 if (rdev == NULL || test_bit(Faulty, &rdev->flags))
6076                         still_degraded = 1;
6077         }
6078         rcu_read_unlock();
6079
6080         bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded);
6081
6082         set_bit(STRIPE_SYNC_REQUESTED, &sh->state);
6083         set_bit(STRIPE_HANDLE, &sh->state);
6084
6085         raid5_release_stripe(sh);
6086
6087         return STRIPE_SECTORS;
6088 }
6089
6090 static int  retry_aligned_read(struct r5conf *conf, struct bio *raid_bio,
6091                                unsigned int offset)
6092 {
6093         /* We may not be able to submit a whole bio at once as there
6094          * may not be enough stripe_heads available.
6095          * We cannot pre-allocate enough stripe_heads as we may need
6096          * more than exist in the cache (if we allow ever large chunks).
6097          * So we do one stripe head at a time and record in
6098          * ->bi_hw_segments how many have been done.
6099          *
6100          * We *know* that this entire raid_bio is in one chunk, so
6101          * it will be only one 'dd_idx' and only need one call to raid5_compute_sector.
6102          */
6103         struct stripe_head *sh;
6104         int dd_idx;
6105         sector_t sector, logical_sector, last_sector;
6106         int scnt = 0;
6107         int handled = 0;
6108
6109         logical_sector = raid_bio->bi_iter.bi_sector &
6110                 ~((sector_t)STRIPE_SECTORS-1);
6111         sector = raid5_compute_sector(conf, logical_sector,
6112                                       0, &dd_idx, NULL);
6113         last_sector = bio_end_sector(raid_bio);
6114
6115         for (; logical_sector < last_sector;
6116              logical_sector += STRIPE_SECTORS,
6117                      sector += STRIPE_SECTORS,
6118                      scnt++) {
6119
6120                 if (scnt < offset)
6121                         /* already done this stripe */
6122                         continue;
6123
6124                 sh = raid5_get_active_stripe(conf, sector, 0, 1, 1);
6125
6126                 if (!sh) {
6127                         /* failed to get a stripe - must wait */
6128                         conf->retry_read_aligned = raid_bio;
6129                         conf->retry_read_offset = scnt;
6130                         return handled;
6131                 }
6132
6133                 if (!add_stripe_bio(sh, raid_bio, dd_idx, 0, 0)) {
6134                         raid5_release_stripe(sh);
6135                         conf->retry_read_aligned = raid_bio;
6136                         conf->retry_read_offset = scnt;
6137                         return handled;
6138                 }
6139
6140                 set_bit(R5_ReadNoMerge, &sh->dev[dd_idx].flags);
6141                 handle_stripe(sh);
6142                 raid5_release_stripe(sh);
6143                 handled++;
6144         }
6145
6146         bio_endio(raid_bio);
6147
6148         if (atomic_dec_and_test(&conf->active_aligned_reads))
6149                 wake_up(&conf->wait_for_quiescent);
6150         return handled;
6151 }
6152
6153 static int handle_active_stripes(struct r5conf *conf, int group,
6154                                  struct r5worker *worker,
6155                                  struct list_head *temp_inactive_list)
6156 {
6157         struct stripe_head *batch[MAX_STRIPE_BATCH], *sh;
6158         int i, batch_size = 0, hash;
6159         bool release_inactive = false;
6160
6161         while (batch_size < MAX_STRIPE_BATCH &&
6162                         (sh = __get_priority_stripe(conf, group)) != NULL)
6163                 batch[batch_size++] = sh;
6164
6165         if (batch_size == 0) {
6166                 for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6167                         if (!list_empty(temp_inactive_list + i))
6168                                 break;
6169                 if (i == NR_STRIPE_HASH_LOCKS) {
6170                         spin_unlock_irq(&conf->device_lock);
6171                         log_flush_stripe_to_raid(conf);
6172                         spin_lock_irq(&conf->device_lock);
6173                         return batch_size;
6174                 }
6175                 release_inactive = true;
6176         }
6177         spin_unlock_irq(&conf->device_lock);
6178
6179         release_inactive_stripe_list(conf, temp_inactive_list,
6180                                      NR_STRIPE_HASH_LOCKS);
6181
6182         r5l_flush_stripe_to_raid(conf->log);
6183         if (release_inactive) {
6184                 spin_lock_irq(&conf->device_lock);
6185                 return 0;
6186         }
6187
6188         for (i = 0; i < batch_size; i++)
6189                 handle_stripe(batch[i]);
6190         log_write_stripe_run(conf);
6191
6192         cond_resched();
6193
6194         spin_lock_irq(&conf->device_lock);
6195         for (i = 0; i < batch_size; i++) {
6196                 hash = batch[i]->hash_lock_index;
6197                 __release_stripe(conf, batch[i], &temp_inactive_list[hash]);
6198         }
6199         return batch_size;
6200 }
6201
6202 static void raid5_do_work(struct work_struct *work)
6203 {
6204         struct r5worker *worker = container_of(work, struct r5worker, work);
6205         struct r5worker_group *group = worker->group;
6206         struct r5conf *conf = group->conf;
6207         struct mddev *mddev = conf->mddev;
6208         int group_id = group - conf->worker_groups;
6209         int handled;
6210         struct blk_plug plug;
6211
6212         pr_debug("+++ raid5worker active\n");
6213
6214         blk_start_plug(&plug);
6215         handled = 0;
6216         spin_lock_irq(&conf->device_lock);
6217         while (1) {
6218                 int batch_size, released;
6219
6220                 released = release_stripe_list(conf, worker->temp_inactive_list);
6221
6222                 batch_size = handle_active_stripes(conf, group_id, worker,
6223                                                    worker->temp_inactive_list);
6224                 worker->working = false;
6225                 if (!batch_size && !released)
6226                         break;
6227                 handled += batch_size;
6228                 wait_event_lock_irq(mddev->sb_wait,
6229                         !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags),
6230                         conf->device_lock);
6231         }
6232         pr_debug("%d stripes handled\n", handled);
6233
6234         spin_unlock_irq(&conf->device_lock);
6235
6236         flush_deferred_bios(conf);
6237
6238         r5l_flush_stripe_to_raid(conf->log);
6239
6240         async_tx_issue_pending_all();
6241         blk_finish_plug(&plug);
6242
6243         pr_debug("--- raid5worker inactive\n");
6244 }
6245
6246 /*
6247  * This is our raid5 kernel thread.
6248  *
6249  * We scan the hash table for stripes which can be handled now.
6250  * During the scan, completed stripes are saved for us by the interrupt
6251  * handler, so that they will not have to wait for our next wakeup.
6252  */
6253 static void raid5d(struct md_thread *thread)
6254 {
6255         struct mddev *mddev = thread->mddev;
6256         struct r5conf *conf = mddev->private;
6257         int handled;
6258         struct blk_plug plug;
6259
6260         pr_debug("+++ raid5d active\n");
6261
6262         md_check_recovery(mddev);
6263
6264         blk_start_plug(&plug);
6265         handled = 0;
6266         spin_lock_irq(&conf->device_lock);
6267         while (1) {
6268                 struct bio *bio;
6269                 int batch_size, released;
6270                 unsigned int offset;
6271
6272                 released = release_stripe_list(conf, conf->temp_inactive_list);
6273                 if (released)
6274                         clear_bit(R5_DID_ALLOC, &conf->cache_state);
6275
6276                 if (
6277                     !list_empty(&conf->bitmap_list)) {
6278                         /* Now is a good time to flush some bitmap updates */
6279                         conf->seq_flush++;
6280                         spin_unlock_irq(&conf->device_lock);
6281                         bitmap_unplug(mddev->bitmap);
6282                         spin_lock_irq(&conf->device_lock);
6283                         conf->seq_write = conf->seq_flush;
6284                         activate_bit_delay(conf, conf->temp_inactive_list);
6285                 }
6286                 raid5_activate_delayed(conf);
6287
6288                 while ((bio = remove_bio_from_retry(conf, &offset))) {
6289                         int ok;
6290                         spin_unlock_irq(&conf->device_lock);
6291                         ok = retry_aligned_read(conf, bio, offset);
6292                         spin_lock_irq(&conf->device_lock);
6293                         if (!ok)
6294                                 break;
6295                         handled++;
6296                 }
6297
6298                 batch_size = handle_active_stripes(conf, ANY_GROUP, NULL,
6299                                                    conf->temp_inactive_list);
6300                 if (!batch_size && !released)
6301                         break;
6302                 handled += batch_size;
6303
6304                 if (mddev->sb_flags & ~(1 << MD_SB_CHANGE_PENDING)) {
6305                         spin_unlock_irq(&conf->device_lock);
6306                         md_check_recovery(mddev);
6307                         spin_lock_irq(&conf->device_lock);
6308                 }
6309         }
6310         pr_debug("%d stripes handled\n", handled);
6311
6312         spin_unlock_irq(&conf->device_lock);
6313         if (test_and_clear_bit(R5_ALLOC_MORE, &conf->cache_state) &&
6314             mutex_trylock(&conf->cache_size_mutex)) {
6315                 grow_one_stripe(conf, __GFP_NOWARN);
6316                 /* Set flag even if allocation failed.  This helps
6317                  * slow down allocation requests when mem is short
6318                  */
6319                 set_bit(R5_DID_ALLOC, &conf->cache_state);
6320                 mutex_unlock(&conf->cache_size_mutex);
6321         }
6322
6323         flush_deferred_bios(conf);
6324
6325         r5l_flush_stripe_to_raid(conf->log);
6326
6327         async_tx_issue_pending_all();
6328         blk_finish_plug(&plug);
6329
6330         pr_debug("--- raid5d inactive\n");
6331 }
6332
6333 static ssize_t
6334 raid5_show_stripe_cache_size(struct mddev *mddev, char *page)
6335 {
6336         struct r5conf *conf;
6337         int ret = 0;
6338         spin_lock(&mddev->lock);
6339         conf = mddev->private;
6340         if (conf)
6341                 ret = sprintf(page, "%d\n", conf->min_nr_stripes);
6342         spin_unlock(&mddev->lock);
6343         return ret;
6344 }
6345
6346 int
6347 raid5_set_cache_size(struct mddev *mddev, int size)
6348 {
6349         struct r5conf *conf = mddev->private;
6350
6351         if (size <= 16 || size > 32768)
6352                 return -EINVAL;
6353
6354         conf->min_nr_stripes = size;
6355         mutex_lock(&conf->cache_size_mutex);
6356         while (size < conf->max_nr_stripes &&
6357                drop_one_stripe(conf))
6358                 ;
6359         mutex_unlock(&conf->cache_size_mutex);
6360
6361         md_allow_write(mddev);
6362
6363         mutex_lock(&conf->cache_size_mutex);
6364         while (size > conf->max_nr_stripes)
6365                 if (!grow_one_stripe(conf, GFP_KERNEL))
6366                         break;
6367         mutex_unlock(&conf->cache_size_mutex);
6368
6369         return 0;
6370 }
6371 EXPORT_SYMBOL(raid5_set_cache_size);
6372
6373 static ssize_t
6374 raid5_store_stripe_cache_size(struct mddev *mddev, const char *page, size_t len)
6375 {
6376         struct r5conf *conf;
6377         unsigned long new;
6378         int err;
6379
6380         if (len >= PAGE_SIZE)
6381                 return -EINVAL;
6382         if (kstrtoul(page, 10, &new))
6383                 return -EINVAL;
6384         err = mddev_lock(mddev);
6385         if (err)
6386                 return err;
6387         conf = mddev->private;
6388         if (!conf)
6389                 err = -ENODEV;
6390         else
6391                 err = raid5_set_cache_size(mddev, new);
6392         mddev_unlock(mddev);
6393
6394         return err ?: len;
6395 }
6396
6397 static struct md_sysfs_entry
6398 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
6399                                 raid5_show_stripe_cache_size,
6400                                 raid5_store_stripe_cache_size);
6401
6402 static ssize_t
6403 raid5_show_rmw_level(struct mddev  *mddev, char *page)
6404 {
6405         struct r5conf *conf = mddev->private;
6406         if (conf)
6407                 return sprintf(page, "%d\n", conf->rmw_level);
6408         else
6409                 return 0;
6410 }
6411
6412 static ssize_t
6413 raid5_store_rmw_level(struct mddev  *mddev, const char *page, size_t len)
6414 {
6415         struct r5conf *conf = mddev->private;
6416         unsigned long new;
6417
6418         if (!conf)
6419                 return -ENODEV;
6420
6421         if (len >= PAGE_SIZE)
6422                 return -EINVAL;
6423
6424         if (kstrtoul(page, 10, &new))
6425                 return -EINVAL;
6426
6427         if (new != PARITY_DISABLE_RMW && !raid6_call.xor_syndrome)
6428                 return -EINVAL;
6429
6430         if (new != PARITY_DISABLE_RMW &&
6431             new != PARITY_ENABLE_RMW &&
6432             new != PARITY_PREFER_RMW)
6433                 return -EINVAL;
6434
6435         conf->rmw_level = new;
6436         return len;
6437 }
6438
6439 static struct md_sysfs_entry
6440 raid5_rmw_level = __ATTR(rmw_level, S_IRUGO | S_IWUSR,
6441                          raid5_show_rmw_level,
6442                          raid5_store_rmw_level);
6443
6444
6445 static ssize_t
6446 raid5_show_preread_threshold(struct mddev *mddev, char *page)
6447 {
6448         struct r5conf *conf;
6449         int ret = 0;
6450         spin_lock(&mddev->lock);
6451         conf = mddev->private;
6452         if (conf)
6453                 ret = sprintf(page, "%d\n", conf->bypass_threshold);
6454         spin_unlock(&mddev->lock);
6455         return ret;
6456 }
6457
6458 static ssize_t
6459 raid5_store_preread_threshold(struct mddev *mddev, const char *page, size_t len)
6460 {
6461         struct r5conf *conf;
6462         unsigned long new;
6463         int err;
6464
6465         if (len >= PAGE_SIZE)
6466                 return -EINVAL;
6467         if (kstrtoul(page, 10, &new))
6468                 return -EINVAL;
6469
6470         err = mddev_lock(mddev);
6471         if (err)
6472                 return err;
6473         conf = mddev->private;
6474         if (!conf)
6475                 err = -ENODEV;
6476         else if (new > conf->min_nr_stripes)
6477                 err = -EINVAL;
6478         else
6479                 conf->bypass_threshold = new;
6480         mddev_unlock(mddev);
6481         return err ?: len;
6482 }
6483
6484 static struct md_sysfs_entry
6485 raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold,
6486                                         S_IRUGO | S_IWUSR,
6487                                         raid5_show_preread_threshold,
6488                                         raid5_store_preread_threshold);
6489
6490 static ssize_t
6491 raid5_show_skip_copy(struct mddev *mddev, char *page)
6492 {
6493         struct r5conf *conf;
6494         int ret = 0;
6495         spin_lock(&mddev->lock);
6496         conf = mddev->private;
6497         if (conf)
6498                 ret = sprintf(page, "%d\n", conf->skip_copy);
6499         spin_unlock(&mddev->lock);
6500         return ret;
6501 }
6502
6503 static ssize_t
6504 raid5_store_skip_copy(struct mddev *mddev, const char *page, size_t len)
6505 {
6506         struct r5conf *conf;
6507         unsigned long new;
6508         int err;
6509
6510         if (len >= PAGE_SIZE)
6511                 return -EINVAL;
6512         if (kstrtoul(page, 10, &new))
6513                 return -EINVAL;
6514         new = !!new;
6515
6516         err = mddev_lock(mddev);
6517         if (err)
6518                 return err;
6519         conf = mddev->private;
6520         if (!conf)
6521                 err = -ENODEV;
6522         else if (new != conf->skip_copy) {
6523                 mddev_suspend(mddev);
6524                 conf->skip_copy = new;
6525                 if (new)
6526                         mddev->queue->backing_dev_info->capabilities |=
6527                                 BDI_CAP_STABLE_WRITES;
6528                 else
6529                         mddev->queue->backing_dev_info->capabilities &=
6530                                 ~BDI_CAP_STABLE_WRITES;
6531                 mddev_resume(mddev);
6532         }
6533         mddev_unlock(mddev);
6534         return err ?: len;
6535 }
6536
6537 static struct md_sysfs_entry
6538 raid5_skip_copy = __ATTR(skip_copy, S_IRUGO | S_IWUSR,
6539                                         raid5_show_skip_copy,
6540                                         raid5_store_skip_copy);
6541
6542 static ssize_t
6543 stripe_cache_active_show(struct mddev *mddev, char *page)
6544 {
6545         struct r5conf *conf = mddev->private;
6546         if (conf)
6547                 return sprintf(page, "%d\n", atomic_read(&conf->active_stripes));
6548         else
6549                 return 0;
6550 }
6551
6552 static struct md_sysfs_entry
6553 raid5_stripecache_active = __ATTR_RO(stripe_cache_active);
6554
6555 static ssize_t
6556 raid5_show_group_thread_cnt(struct mddev *mddev, char *page)
6557 {
6558         struct r5conf *conf;
6559         int ret = 0;
6560         spin_lock(&mddev->lock);
6561         conf = mddev->private;
6562         if (conf)
6563                 ret = sprintf(page, "%d\n", conf->worker_cnt_per_group);
6564         spin_unlock(&mddev->lock);
6565         return ret;
6566 }
6567
6568 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6569                                int *group_cnt,
6570                                int *worker_cnt_per_group,
6571                                struct r5worker_group **worker_groups);
6572 static ssize_t
6573 raid5_store_group_thread_cnt(struct mddev *mddev, const char *page, size_t len)
6574 {
6575         struct r5conf *conf;
6576         unsigned int new;
6577         int err;
6578         struct r5worker_group *new_groups, *old_groups;
6579         int group_cnt, worker_cnt_per_group;
6580
6581         if (len >= PAGE_SIZE)
6582                 return -EINVAL;
6583         if (kstrtouint(page, 10, &new))
6584                 return -EINVAL;
6585         /* 8192 should be big enough */
6586         if (new > 8192)
6587                 return -EINVAL;
6588
6589         err = mddev_lock(mddev);
6590         if (err)
6591                 return err;
6592         conf = mddev->private;
6593         if (!conf)
6594                 err = -ENODEV;
6595         else if (new != conf->worker_cnt_per_group) {
6596                 mddev_suspend(mddev);
6597
6598                 old_groups = conf->worker_groups;
6599                 if (old_groups)
6600                         flush_workqueue(raid5_wq);
6601
6602                 err = alloc_thread_groups(conf, new,
6603                                           &group_cnt, &worker_cnt_per_group,
6604                                           &new_groups);
6605                 if (!err) {
6606                         spin_lock_irq(&conf->device_lock);
6607                         conf->group_cnt = group_cnt;
6608                         conf->worker_cnt_per_group = worker_cnt_per_group;
6609                         conf->worker_groups = new_groups;
6610                         spin_unlock_irq(&conf->device_lock);
6611
6612                         if (old_groups)
6613                                 kfree(old_groups[0].workers);
6614                         kfree(old_groups);
6615                 }
6616                 mddev_resume(mddev);
6617         }
6618         mddev_unlock(mddev);
6619
6620         return err ?: len;
6621 }
6622
6623 static struct md_sysfs_entry
6624 raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR,
6625                                 raid5_show_group_thread_cnt,
6626                                 raid5_store_group_thread_cnt);
6627
6628 static struct attribute *raid5_attrs[] =  {
6629         &raid5_stripecache_size.attr,
6630         &raid5_stripecache_active.attr,
6631         &raid5_preread_bypass_threshold.attr,
6632         &raid5_group_thread_cnt.attr,
6633         &raid5_skip_copy.attr,
6634         &raid5_rmw_level.attr,
6635         &r5c_journal_mode.attr,
6636         NULL,
6637 };
6638 static struct attribute_group raid5_attrs_group = {
6639         .name = NULL,
6640         .attrs = raid5_attrs,
6641 };
6642
6643 static int alloc_thread_groups(struct r5conf *conf, int cnt,
6644                                int *group_cnt,
6645                                int *worker_cnt_per_group,
6646                                struct r5worker_group **worker_groups)
6647 {
6648         int i, j, k;
6649         ssize_t size;
6650         struct r5worker *workers;
6651
6652         *worker_cnt_per_group = cnt;
6653         if (cnt == 0) {
6654                 *group_cnt = 0;
6655                 *worker_groups = NULL;
6656                 return 0;
6657         }
6658         *group_cnt = num_possible_nodes();
6659         size = sizeof(struct r5worker) * cnt;
6660         workers = kzalloc(size * *group_cnt, GFP_NOIO);
6661         *worker_groups = kzalloc(sizeof(struct r5worker_group) *
6662                                 *group_cnt, GFP_NOIO);
6663         if (!*worker_groups || !workers) {
6664                 kfree(workers);
6665                 kfree(*worker_groups);
6666                 return -ENOMEM;
6667         }
6668
6669         for (i = 0; i < *group_cnt; i++) {
6670                 struct r5worker_group *group;
6671
6672                 group = &(*worker_groups)[i];
6673                 INIT_LIST_HEAD(&group->handle_list);
6674                 INIT_LIST_HEAD(&group->loprio_list);
6675                 group->conf = conf;
6676                 group->workers = workers + i * cnt;
6677
6678                 for (j = 0; j < cnt; j++) {
6679                         struct r5worker *worker = group->workers + j;
6680                         worker->group = group;
6681                         INIT_WORK(&worker->work, raid5_do_work);
6682
6683                         for (k = 0; k < NR_STRIPE_HASH_LOCKS; k++)
6684                                 INIT_LIST_HEAD(worker->temp_inactive_list + k);
6685                 }
6686         }
6687
6688         return 0;
6689 }
6690
6691 static void free_thread_groups(struct r5conf *conf)
6692 {
6693         if (conf->worker_groups)
6694                 kfree(conf->worker_groups[0].workers);
6695         kfree(conf->worker_groups);
6696         conf->worker_groups = NULL;
6697 }
6698
6699 static sector_t
6700 raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks)
6701 {
6702         struct r5conf *conf = mddev->private;
6703
6704         if (!sectors)
6705                 sectors = mddev->dev_sectors;
6706         if (!raid_disks)
6707                 /* size is defined by the smallest of previous and new size */
6708                 raid_disks = min(conf->raid_disks, conf->previous_raid_disks);
6709
6710         sectors &= ~((sector_t)conf->chunk_sectors - 1);
6711         sectors &= ~((sector_t)conf->prev_chunk_sectors - 1);
6712         return sectors * (raid_disks - conf->max_degraded);
6713 }
6714
6715 static void free_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6716 {
6717         safe_put_page(percpu->spare_page);
6718         if (percpu->scribble)
6719                 flex_array_free(percpu->scribble);
6720         percpu->spare_page = NULL;
6721         percpu->scribble = NULL;
6722 }
6723
6724 static int alloc_scratch_buffer(struct r5conf *conf, struct raid5_percpu *percpu)
6725 {
6726         if (conf->level == 6 && !percpu->spare_page)
6727                 percpu->spare_page = alloc_page(GFP_KERNEL);
6728         if (!percpu->scribble)
6729                 percpu->scribble = scribble_alloc(max(conf->raid_disks,
6730                                                       conf->previous_raid_disks),
6731                                                   max(conf->chunk_sectors,
6732                                                       conf->prev_chunk_sectors)
6733                                                    / STRIPE_SECTORS,
6734                                                   GFP_KERNEL);
6735
6736         if (!percpu->scribble || (conf->level == 6 && !percpu->spare_page)) {
6737                 free_scratch_buffer(conf, percpu);
6738                 return -ENOMEM;
6739         }
6740
6741         return 0;
6742 }
6743
6744 static int raid456_cpu_dead(unsigned int cpu, struct hlist_node *node)
6745 {
6746         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6747
6748         free_scratch_buffer(conf, per_cpu_ptr(conf->percpu, cpu));
6749         return 0;
6750 }
6751
6752 static void raid5_free_percpu(struct r5conf *conf)
6753 {
6754         if (!conf->percpu)
6755                 return;
6756
6757         cpuhp_state_remove_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6758         free_percpu(conf->percpu);
6759 }
6760
6761 static void free_conf(struct r5conf *conf)
6762 {
6763         int i;
6764
6765         log_exit(conf);
6766
6767         if (conf->shrinker.nr_deferred)
6768                 unregister_shrinker(&conf->shrinker);
6769
6770         free_thread_groups(conf);
6771         shrink_stripes(conf);
6772         raid5_free_percpu(conf);
6773         for (i = 0; i < conf->pool_size; i++)
6774                 if (conf->disks[i].extra_page)
6775                         put_page(conf->disks[i].extra_page);
6776         kfree(conf->disks);
6777         if (conf->bio_split)
6778                 bioset_free(conf->bio_split);
6779         kfree(conf->stripe_hashtbl);
6780         kfree(conf->pending_data);
6781         kfree(conf);
6782 }
6783
6784 static int raid456_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)
6785 {
6786         struct r5conf *conf = hlist_entry_safe(node, struct r5conf, node);
6787         struct raid5_percpu *percpu = per_cpu_ptr(conf->percpu, cpu);
6788
6789         if (alloc_scratch_buffer(conf, percpu)) {
6790                 pr_warn("%s: failed memory allocation for cpu%u\n",
6791                         __func__, cpu);
6792                 return -ENOMEM;
6793         }
6794         return 0;
6795 }
6796
6797 static int raid5_alloc_percpu(struct r5conf *conf)
6798 {
6799         int err = 0;
6800
6801         conf->percpu = alloc_percpu(struct raid5_percpu);
6802         if (!conf->percpu)
6803                 return -ENOMEM;
6804
6805         err = cpuhp_state_add_instance(CPUHP_MD_RAID5_PREPARE, &conf->node);
6806         if (!err) {
6807                 conf->scribble_disks = max(conf->raid_disks,
6808                         conf->previous_raid_disks);
6809                 conf->scribble_sectors = max(conf->chunk_sectors,
6810                         conf->prev_chunk_sectors);
6811         }
6812         return err;
6813 }
6814
6815 static unsigned long raid5_cache_scan(struct shrinker *shrink,
6816                                       struct shrink_control *sc)
6817 {
6818         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6819         unsigned long ret = SHRINK_STOP;
6820
6821         if (mutex_trylock(&conf->cache_size_mutex)) {
6822                 ret= 0;
6823                 while (ret < sc->nr_to_scan &&
6824                        conf->max_nr_stripes > conf->min_nr_stripes) {
6825                         if (drop_one_stripe(conf) == 0) {
6826                                 ret = SHRINK_STOP;
6827                                 break;
6828                         }
6829                         ret++;
6830                 }
6831                 mutex_unlock(&conf->cache_size_mutex);
6832         }
6833         return ret;
6834 }
6835
6836 static unsigned long raid5_cache_count(struct shrinker *shrink,
6837                                        struct shrink_control *sc)
6838 {
6839         struct r5conf *conf = container_of(shrink, struct r5conf, shrinker);
6840
6841         if (conf->max_nr_stripes < conf->min_nr_stripes)
6842                 /* unlikely, but not impossible */
6843                 return 0;
6844         return conf->max_nr_stripes - conf->min_nr_stripes;
6845 }
6846
6847 static struct r5conf *setup_conf(struct mddev *mddev)
6848 {
6849         struct r5conf *conf;
6850         int raid_disk, memory, max_disks;
6851         struct md_rdev *rdev;
6852         struct disk_info *disk;
6853         char pers_name[6];
6854         int i;
6855         int group_cnt, worker_cnt_per_group;
6856         struct r5worker_group *new_group;
6857
6858         if (mddev->new_level != 5
6859             && mddev->new_level != 4
6860             && mddev->new_level != 6) {
6861                 pr_warn("md/raid:%s: raid level not set to 4/5/6 (%d)\n",
6862                         mdname(mddev), mddev->new_level);
6863                 return ERR_PTR(-EIO);
6864         }
6865         if ((mddev->new_level == 5
6866              && !algorithm_valid_raid5(mddev->new_layout)) ||
6867             (mddev->new_level == 6
6868              && !algorithm_valid_raid6(mddev->new_layout))) {
6869                 pr_warn("md/raid:%s: layout %d not supported\n",
6870                         mdname(mddev), mddev->new_layout);
6871                 return ERR_PTR(-EIO);
6872         }
6873         if (mddev->new_level == 6 && mddev->raid_disks < 4) {
6874                 pr_warn("md/raid:%s: not enough configured devices (%d, minimum 4)\n",
6875                         mdname(mddev), mddev->raid_disks);
6876                 return ERR_PTR(-EINVAL);
6877         }
6878
6879         if (!mddev->new_chunk_sectors ||
6880             (mddev->new_chunk_sectors << 9) % PAGE_SIZE ||
6881             !is_power_of_2(mddev->new_chunk_sectors)) {
6882                 pr_warn("md/raid:%s: invalid chunk size %d\n",
6883                         mdname(mddev), mddev->new_chunk_sectors << 9);
6884                 return ERR_PTR(-EINVAL);
6885         }
6886
6887         conf = kzalloc(sizeof(struct r5conf), GFP_KERNEL);
6888         if (conf == NULL)
6889                 goto abort;
6890         INIT_LIST_HEAD(&conf->free_list);
6891         INIT_LIST_HEAD(&conf->pending_list);
6892         conf->pending_data = kzalloc(sizeof(struct r5pending_data) *
6893                 PENDING_IO_MAX, GFP_KERNEL);
6894         if (!conf->pending_data)
6895                 goto abort;
6896         for (i = 0; i < PENDING_IO_MAX; i++)
6897                 list_add(&conf->pending_data[i].sibling, &conf->free_list);
6898         /* Don't enable multi-threading by default*/
6899         if (!alloc_thread_groups(conf, 0, &group_cnt, &worker_cnt_per_group,
6900                                  &new_group)) {
6901                 conf->group_cnt = group_cnt;
6902                 conf->worker_cnt_per_group = worker_cnt_per_group;
6903                 conf->worker_groups = new_group;
6904         } else
6905                 goto abort;
6906         spin_lock_init(&conf->device_lock);
6907         seqcount_init(&conf->gen_lock);
6908         mutex_init(&conf->cache_size_mutex);
6909         init_waitqueue_head(&conf->wait_for_quiescent);
6910         init_waitqueue_head(&conf->wait_for_stripe);
6911         init_waitqueue_head(&conf->wait_for_overlap);
6912         INIT_LIST_HEAD(&conf->handle_list);
6913         INIT_LIST_HEAD(&conf->loprio_list);
6914         INIT_LIST_HEAD(&conf->hold_list);
6915         INIT_LIST_HEAD(&conf->delayed_list);
6916         INIT_LIST_HEAD(&conf->bitmap_list);
6917         init_llist_head(&conf->released_stripes);
6918         atomic_set(&conf->active_stripes, 0);
6919         atomic_set(&conf->preread_active_stripes, 0);
6920         atomic_set(&conf->active_aligned_reads, 0);
6921         spin_lock_init(&conf->pending_bios_lock);
6922         conf->batch_bio_dispatch = true;
6923         rdev_for_each(rdev, mddev) {
6924                 if (test_bit(Journal, &rdev->flags))
6925                         continue;
6926                 if (blk_queue_nonrot(bdev_get_queue(rdev->bdev))) {
6927                         conf->batch_bio_dispatch = false;
6928                         break;
6929                 }
6930         }
6931
6932         conf->bypass_threshold = BYPASS_THRESHOLD;
6933         conf->recovery_disabled = mddev->recovery_disabled - 1;
6934
6935         conf->raid_disks = mddev->raid_disks;
6936         if (mddev->reshape_position == MaxSector)
6937                 conf->previous_raid_disks = mddev->raid_disks;
6938         else
6939                 conf->previous_raid_disks = mddev->raid_disks - mddev->delta_disks;
6940         max_disks = max(conf->raid_disks, conf->previous_raid_disks);
6941
6942         conf->disks = kzalloc(max_disks * sizeof(struct disk_info),
6943                               GFP_KERNEL);
6944
6945         if (!conf->disks)
6946                 goto abort;
6947
6948         for (i = 0; i < max_disks; i++) {
6949                 conf->disks[i].extra_page = alloc_page(GFP_KERNEL);
6950                 if (!conf->disks[i].extra_page)
6951                         goto abort;
6952         }
6953
6954         conf->bio_split = bioset_create(BIO_POOL_SIZE, 0, 0);
6955         if (!conf->bio_split)
6956                 goto abort;
6957         conf->mddev = mddev;
6958
6959         if ((conf->stripe_hashtbl = kzalloc(PAGE_SIZE, GFP_KERNEL)) == NULL)
6960                 goto abort;
6961
6962         /* We init hash_locks[0] separately to that it can be used
6963          * as the reference lock in the spin_lock_nest_lock() call
6964          * in lock_all_device_hash_locks_irq in order to convince
6965          * lockdep that we know what we are doing.
6966          */
6967         spin_lock_init(conf->hash_locks);
6968         for (i = 1; i < NR_STRIPE_HASH_LOCKS; i++)
6969                 spin_lock_init(conf->hash_locks + i);
6970
6971         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6972                 INIT_LIST_HEAD(conf->inactive_list + i);
6973
6974         for (i = 0; i < NR_STRIPE_HASH_LOCKS; i++)
6975                 INIT_LIST_HEAD(conf->temp_inactive_list + i);
6976
6977         atomic_set(&conf->r5c_cached_full_stripes, 0);
6978         INIT_LIST_HEAD(&conf->r5c_full_stripe_list);
6979         atomic_set(&conf->r5c_cached_partial_stripes, 0);
6980         INIT_LIST_HEAD(&conf->r5c_partial_stripe_list);
6981         atomic_set(&conf->r5c_flushing_full_stripes, 0);
6982         atomic_set(&conf->r5c_flushing_partial_stripes, 0);
6983
6984         conf->level = mddev->new_level;
6985         conf->chunk_sectors = mddev->new_chunk_sectors;
6986         if (raid5_alloc_percpu(conf) != 0)
6987                 goto abort;
6988
6989         pr_debug("raid456: run(%s) called.\n", mdname(mddev));
6990
6991         rdev_for_each(rdev, mddev) {
6992                 raid_disk = rdev->raid_disk;
6993                 if (raid_disk >= max_disks
6994                     || raid_disk < 0 || test_bit(Journal, &rdev->flags))
6995                         continue;
6996                 disk = conf->disks + raid_disk;
6997
6998                 if (test_bit(Replacement, &rdev->flags)) {
6999                         if (disk->replacement)
7000                                 goto abort;
7001                         disk->replacement = rdev;
7002                 } else {
7003                         if (disk->rdev)
7004                                 goto abort;
7005                         disk->rdev = rdev;
7006                 }
7007
7008                 if (test_bit(In_sync, &rdev->flags)) {
7009                         char b[BDEVNAME_SIZE];
7010                         pr_info("md/raid:%s: device %s operational as raid disk %d\n",
7011                                 mdname(mddev), bdevname(rdev->bdev, b), raid_disk);
7012                 } else if (rdev->saved_raid_disk != raid_disk)
7013                         /* Cannot rely on bitmap to complete recovery */
7014                         conf->fullsync = 1;
7015         }
7016
7017         conf->level = mddev->new_level;
7018         if (conf->level == 6) {
7019                 conf->max_degraded = 2;
7020                 if (raid6_call.xor_syndrome)
7021                         conf->rmw_level = PARITY_ENABLE_RMW;
7022                 else
7023                         conf->rmw_level = PARITY_DISABLE_RMW;
7024         } else {
7025                 conf->max_degraded = 1;
7026                 conf->rmw_level = PARITY_ENABLE_RMW;
7027         }
7028         conf->algorithm = mddev->new_layout;
7029         conf->reshape_progress = mddev->reshape_position;
7030         if (conf->reshape_progress != MaxSector) {
7031                 conf->prev_chunk_sectors = mddev->chunk_sectors;
7032                 conf->prev_algo = mddev->layout;
7033         } else {
7034                 conf->prev_chunk_sectors = conf->chunk_sectors;
7035                 conf->prev_algo = conf->algorithm;
7036         }
7037
7038         conf->min_nr_stripes = NR_STRIPES;
7039         if (mddev->reshape_position != MaxSector) {
7040                 int stripes = max_t(int,
7041                         ((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4,
7042                         ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4);
7043                 conf->min_nr_stripes = max(NR_STRIPES, stripes);
7044                 if (conf->min_nr_stripes != NR_STRIPES)
7045                         pr_info("md/raid:%s: force stripe size %d for reshape\n",
7046                                 mdname(mddev), conf->min_nr_stripes);
7047         }
7048         memory = conf->min_nr_stripes * (sizeof(struct stripe_head) +
7049                  max_disks * ((sizeof(struct bio) + PAGE_SIZE))) / 1024;
7050         atomic_set(&conf->empty_inactive_list_nr, NR_STRIPE_HASH_LOCKS);
7051         if (grow_stripes(conf, conf->min_nr_stripes)) {
7052                 pr_warn("md/raid:%s: couldn't allocate %dkB for buffers\n",
7053                         mdname(mddev), memory);
7054                 goto abort;
7055         } else
7056                 pr_debug("md/raid:%s: allocated %dkB\n", mdname(mddev), memory);
7057         /*
7058          * Losing a stripe head costs more than the time to refill it,
7059          * it reduces the queue depth and so can hurt throughput.
7060          * So set it rather large, scaled by number of devices.
7061          */
7062         conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4;
7063         conf->shrinker.scan_objects = raid5_cache_scan;
7064         conf->shrinker.count_objects = raid5_cache_count;
7065         conf->shrinker.batch = 128;
7066         conf->shrinker.flags = 0;
7067         if (register_shrinker(&conf->shrinker)) {
7068                 pr_warn("md/raid:%s: couldn't register shrinker.\n",
7069                         mdname(mddev));
7070                 goto abort;
7071         }
7072
7073         sprintf(pers_name, "raid%d", mddev->new_level);
7074         conf->thread = md_register_thread(raid5d, mddev, pers_name);
7075         if (!conf->thread) {
7076                 pr_warn("md/raid:%s: couldn't allocate thread.\n",
7077                         mdname(mddev));
7078                 goto abort;
7079         }
7080
7081         return conf;
7082
7083  abort:
7084         if (conf) {
7085                 free_conf(conf);
7086                 return ERR_PTR(-EIO);
7087         } else
7088                 return ERR_PTR(-ENOMEM);
7089 }
7090
7091 static int only_parity(int raid_disk, int algo, int raid_disks, int max_degraded)
7092 {
7093         switch (algo) {
7094         case ALGORITHM_PARITY_0:
7095                 if (raid_disk < max_degraded)
7096                         return 1;
7097                 break;
7098         case ALGORITHM_PARITY_N:
7099                 if (raid_disk >= raid_disks - max_degraded)
7100                         return 1;
7101                 break;
7102         case ALGORITHM_PARITY_0_6:
7103                 if (raid_disk == 0 ||
7104                     raid_disk == raid_disks - 1)
7105                         return 1;
7106                 break;
7107         case ALGORITHM_LEFT_ASYMMETRIC_6:
7108         case ALGORITHM_RIGHT_ASYMMETRIC_6:
7109         case ALGORITHM_LEFT_SYMMETRIC_6:
7110         case ALGORITHM_RIGHT_SYMMETRIC_6:
7111                 if (raid_disk == raid_disks - 1)
7112                         return 1;
7113         }
7114         return 0;
7115 }
7116
7117 static int raid5_run(struct mddev *mddev)
7118 {
7119         struct r5conf *conf;
7120         int working_disks = 0;
7121         int dirty_parity_disks = 0;
7122         struct md_rdev *rdev;
7123         struct md_rdev *journal_dev = NULL;
7124         sector_t reshape_offset = 0;
7125         int i;
7126         long long min_offset_diff = 0;
7127         int first = 1;
7128
7129         if (mddev_init_writes_pending(mddev) < 0)
7130                 return -ENOMEM;
7131
7132         if (mddev->recovery_cp != MaxSector)
7133                 pr_notice("md/raid:%s: not clean -- starting background reconstruction\n",
7134                           mdname(mddev));
7135
7136         rdev_for_each(rdev, mddev) {
7137                 long long diff;
7138
7139                 if (test_bit(Journal, &rdev->flags)) {
7140                         journal_dev = rdev;
7141                         continue;
7142                 }
7143                 if (rdev->raid_disk < 0)
7144                         continue;
7145                 diff = (rdev->new_data_offset - rdev->data_offset);
7146                 if (first) {
7147                         min_offset_diff = diff;
7148                         first = 0;
7149                 } else if (mddev->reshape_backwards &&
7150                          diff < min_offset_diff)
7151                         min_offset_diff = diff;
7152                 else if (!mddev->reshape_backwards &&
7153                          diff > min_offset_diff)
7154                         min_offset_diff = diff;
7155         }
7156
7157         if ((test_bit(MD_HAS_JOURNAL, &mddev->flags) || journal_dev) &&
7158             (mddev->bitmap_info.offset || mddev->bitmap_info.file)) {
7159                 pr_notice("md/raid:%s: array cannot have both journal and bitmap\n",
7160                           mdname(mddev));
7161                 return -EINVAL;
7162         }
7163
7164         if (mddev->reshape_position != MaxSector) {
7165                 /* Check that we can continue the reshape.
7166                  * Difficulties arise if the stripe we would write to
7167                  * next is at or after the stripe we would read from next.
7168                  * For a reshape that changes the number of devices, this
7169                  * is only possible for a very short time, and mdadm makes
7170                  * sure that time appears to have past before assembling
7171                  * the array.  So we fail if that time hasn't passed.
7172                  * For a reshape that keeps the number of devices the same
7173                  * mdadm must be monitoring the reshape can keeping the
7174                  * critical areas read-only and backed up.  It will start
7175                  * the array in read-only mode, so we check for that.
7176                  */
7177                 sector_t here_new, here_old;
7178                 int old_disks;
7179                 int max_degraded = (mddev->level == 6 ? 2 : 1);
7180                 int chunk_sectors;
7181                 int new_data_disks;
7182
7183                 if (journal_dev) {
7184                         pr_warn("md/raid:%s: don't support reshape with journal - aborting.\n",
7185                                 mdname(mddev));
7186                         return -EINVAL;
7187                 }
7188
7189                 if (mddev->new_level != mddev->level) {
7190                         pr_warn("md/raid:%s: unsupported reshape required - aborting.\n",
7191                                 mdname(mddev));
7192                         return -EINVAL;
7193                 }
7194                 old_disks = mddev->raid_disks - mddev->delta_disks;
7195                 /* reshape_position must be on a new-stripe boundary, and one
7196                  * further up in new geometry must map after here in old
7197                  * geometry.
7198                  * If the chunk sizes are different, then as we perform reshape
7199                  * in units of the largest of the two, reshape_position needs
7200                  * be a multiple of the largest chunk size times new data disks.
7201                  */
7202                 here_new = mddev->reshape_position;
7203                 chunk_sectors = max(mddev->chunk_sectors, mddev->new_chunk_sectors);
7204                 new_data_disks = mddev->raid_disks - max_degraded;
7205                 if (sector_div(here_new, chunk_sectors * new_data_disks)) {
7206                         pr_warn("md/raid:%s: reshape_position not on a stripe boundary\n",
7207                                 mdname(mddev));
7208                         return -EINVAL;
7209                 }
7210                 reshape_offset = here_new * chunk_sectors;
7211                 /* here_new is the stripe we will write to */
7212                 here_old = mddev->reshape_position;
7213                 sector_div(here_old, chunk_sectors * (old_disks-max_degraded));
7214                 /* here_old is the first stripe that we might need to read
7215                  * from */
7216                 if (mddev->delta_disks == 0) {
7217                         /* We cannot be sure it is safe to start an in-place
7218                          * reshape.  It is only safe if user-space is monitoring
7219                          * and taking constant backups.
7220                          * mdadm always starts a situation like this in
7221                          * readonly mode so it can take control before
7222                          * allowing any writes.  So just check for that.
7223                          */
7224                         if (abs(min_offset_diff) >= mddev->chunk_sectors &&
7225                             abs(min_offset_diff) >= mddev->new_chunk_sectors)
7226                                 /* not really in-place - so OK */;
7227                         else if (mddev->ro == 0) {
7228                                 pr_warn("md/raid:%s: in-place reshape must be started in read-only mode - aborting\n",
7229                                         mdname(mddev));
7230                                 return -EINVAL;
7231                         }
7232                 } else if (mddev->reshape_backwards
7233                     ? (here_new * chunk_sectors + min_offset_diff <=
7234                        here_old * chunk_sectors)
7235                     : (here_new * chunk_sectors >=
7236                        here_old * chunk_sectors + (-min_offset_diff))) {
7237                         /* Reading from the same stripe as writing to - bad */
7238                         pr_warn("md/raid:%s: reshape_position too early for auto-recovery - aborting.\n",
7239                                 mdname(mddev));
7240                         return -EINVAL;
7241                 }
7242                 pr_debug("md/raid:%s: reshape will continue\n", mdname(mddev));
7243                 /* OK, we should be able to continue; */
7244         } else {
7245                 BUG_ON(mddev->level != mddev->new_level);
7246                 BUG_ON(mddev->layout != mddev->new_layout);
7247                 BUG_ON(mddev->chunk_sectors != mddev->new_chunk_sectors);
7248                 BUG_ON(mddev->delta_disks != 0);
7249         }
7250
7251         if (test_bit(MD_HAS_JOURNAL, &mddev->flags) &&
7252             test_bit(MD_HAS_PPL, &mddev->flags)) {
7253                 pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n",
7254                         mdname(mddev));
7255                 clear_bit(MD_HAS_PPL, &mddev->flags);
7256                 clear_bit(MD_HAS_MULTIPLE_PPLS, &mddev->flags);
7257         }
7258
7259         if (mddev->private == NULL)
7260                 conf = setup_conf(mddev);
7261         else
7262                 conf = mddev->private;
7263
7264         if (IS_ERR(conf))
7265                 return PTR_ERR(conf);
7266
7267         if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
7268                 if (!journal_dev) {
7269                         pr_warn("md/raid:%s: journal disk is missing, force array readonly\n",
7270                                 mdname(mddev));
7271                         mddev->ro = 1;
7272                         set_disk_ro(mddev->gendisk, 1);
7273                 } else if (mddev->recovery_cp == MaxSector)
7274                         set_bit(MD_JOURNAL_CLEAN, &mddev->flags);
7275         }
7276
7277         conf->min_offset_diff = min_offset_diff;
7278         mddev->thread = conf->thread;
7279         conf->thread = NULL;
7280         mddev->private = conf;
7281
7282         for (i = 0; i < conf->raid_disks && conf->previous_raid_disks;
7283              i++) {
7284                 rdev = conf->disks[i].rdev;
7285                 if (!rdev && conf->disks[i].replacement) {
7286                         /* The replacement is all we have yet */
7287                         rdev = conf->disks[i].replacement;
7288                         conf->disks[i].replacement = NULL;
7289                         clear_bit(Replacement, &rdev->flags);
7290                         conf->disks[i].rdev = rdev;
7291                 }
7292                 if (!rdev)
7293                         continue;
7294                 if (conf->disks[i].replacement &&
7295                     conf->reshape_progress != MaxSector) {
7296                         /* replacements and reshape simply do not mix. */
7297                         pr_warn("md: cannot handle concurrent replacement and reshape.\n");
7298                         goto abort;
7299                 }
7300                 if (test_bit(In_sync, &rdev->flags)) {
7301                         working_disks++;
7302                         continue;
7303                 }
7304                 /* This disc is not fully in-sync.  However if it
7305                  * just stored parity (beyond the recovery_offset),
7306                  * when we don't need to be concerned about the
7307                  * array being dirty.
7308                  * When reshape goes 'backwards', we never have
7309                  * partially completed devices, so we only need
7310                  * to worry about reshape going forwards.
7311                  */
7312                 /* Hack because v0.91 doesn't store recovery_offset properly. */
7313                 if (mddev->major_version == 0 &&
7314                     mddev->minor_version > 90)
7315                         rdev->recovery_offset = reshape_offset;
7316
7317                 if (rdev->recovery_offset < reshape_offset) {
7318                         /* We need to check old and new layout */
7319                         if (!only_parity(rdev->raid_disk,
7320                                          conf->algorithm,
7321                                          conf->raid_disks,
7322                                          conf->max_degraded))
7323                                 continue;
7324                 }
7325                 if (!only_parity(rdev->raid_disk,
7326                                  conf->prev_algo,
7327                                  conf->previous_raid_disks,
7328                                  conf->max_degraded))
7329                         continue;
7330                 dirty_parity_disks++;
7331         }
7332
7333         /*
7334          * 0 for a fully functional array, 1 or 2 for a degraded array.
7335          */
7336         mddev->degraded = raid5_calc_degraded(conf);
7337
7338         if (has_failed(conf)) {
7339                 pr_crit("md/raid:%s: not enough operational devices (%d/%d failed)\n",
7340                         mdname(mddev), mddev->degraded, conf->raid_disks);
7341                 goto abort;
7342         }
7343
7344         /* device size must be a multiple of chunk size */
7345         mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
7346         mddev->resync_max_sectors = mddev->dev_sectors;
7347
7348         if (mddev->degraded > dirty_parity_disks &&
7349             mddev->recovery_cp != MaxSector) {
7350                 if (test_bit(MD_HAS_PPL, &mddev->flags))
7351                         pr_crit("md/raid:%s: starting dirty degraded array with PPL.\n",
7352                                 mdname(mddev));
7353                 else if (mddev->ok_start_degraded)
7354                         pr_crit("md/raid:%s: starting dirty degraded array - data corruption possible.\n",
7355                                 mdname(mddev));
7356                 else {
7357                         pr_crit("md/raid:%s: cannot start dirty degraded array.\n",
7358                                 mdname(mddev));
7359                         goto abort;
7360                 }
7361         }
7362
7363         pr_info("md/raid:%s: raid level %d active with %d out of %d devices, algorithm %d\n",
7364                 mdname(mddev), conf->level,
7365                 mddev->raid_disks-mddev->degraded, mddev->raid_disks,
7366                 mddev->new_layout);
7367
7368         print_raid5_conf(conf);
7369
7370         if (conf->reshape_progress != MaxSector) {
7371                 conf->reshape_safe = conf->reshape_progress;
7372                 atomic_set(&conf->reshape_stripes, 0);
7373                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7374                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7375                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7376                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7377                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7378                                                         "reshape");
7379         }
7380
7381         /* Ok, everything is just fine now */
7382         if (mddev->to_remove == &raid5_attrs_group)
7383                 mddev->to_remove = NULL;
7384         else if (mddev->kobj.sd &&
7385             sysfs_create_group(&mddev->kobj, &raid5_attrs_group))
7386                 pr_warn("raid5: failed to create sysfs attributes for %s\n",
7387                         mdname(mddev));
7388         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
7389
7390         if (mddev->queue) {
7391                 int chunk_size;
7392                 /* read-ahead size must cover two whole stripes, which
7393                  * is 2 * (datadisks) * chunksize where 'n' is the
7394                  * number of raid devices
7395                  */
7396                 int data_disks = conf->previous_raid_disks - conf->max_degraded;
7397                 int stripe = data_disks *
7398                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
7399                 if (mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7400                         mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7401
7402                 chunk_size = mddev->chunk_sectors << 9;
7403                 blk_queue_io_min(mddev->queue, chunk_size);
7404                 blk_queue_io_opt(mddev->queue, chunk_size *
7405                                  (conf->raid_disks - conf->max_degraded));
7406                 mddev->queue->limits.raid_partial_stripes_expensive = 1;
7407                 /*
7408                  * We can only discard a whole stripe. It doesn't make sense to
7409                  * discard data disk but write parity disk
7410                  */
7411                 stripe = stripe * PAGE_SIZE;
7412                 /* Round up to power of 2, as discard handling
7413                  * currently assumes that */
7414                 while ((stripe-1) & stripe)
7415                         stripe = (stripe | (stripe-1)) + 1;
7416                 mddev->queue->limits.discard_alignment = stripe;
7417                 mddev->queue->limits.discard_granularity = stripe;
7418
7419                 blk_queue_max_write_same_sectors(mddev->queue, 0);
7420                 blk_queue_max_write_zeroes_sectors(mddev->queue, 0);
7421
7422                 rdev_for_each(rdev, mddev) {
7423                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7424                                           rdev->data_offset << 9);
7425                         disk_stack_limits(mddev->gendisk, rdev->bdev,
7426                                           rdev->new_data_offset << 9);
7427                 }
7428
7429                 /*
7430                  * zeroing is required, otherwise data
7431                  * could be lost. Consider a scenario: discard a stripe
7432                  * (the stripe could be inconsistent if
7433                  * discard_zeroes_data is 0); write one disk of the
7434                  * stripe (the stripe could be inconsistent again
7435                  * depending on which disks are used to calculate
7436                  * parity); the disk is broken; The stripe data of this
7437                  * disk is lost.
7438                  *
7439                  * We only allow DISCARD if the sysadmin has confirmed that
7440                  * only safe devices are in use by setting a module parameter.
7441                  * A better idea might be to turn DISCARD into WRITE_ZEROES
7442                  * requests, as that is required to be safe.
7443                  */
7444                 if (devices_handle_discard_safely &&
7445                     mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
7446                     mddev->queue->limits.discard_granularity >= stripe)
7447                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
7448                                                 mddev->queue);
7449                 else
7450                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
7451                                                 mddev->queue);
7452
7453                 blk_queue_max_hw_sectors(mddev->queue, UINT_MAX);
7454         }
7455
7456         if (log_init(conf, journal_dev, raid5_has_ppl(conf)))
7457                 goto abort;
7458
7459         return 0;
7460 abort:
7461         md_unregister_thread(&mddev->thread);
7462         print_raid5_conf(conf);
7463         free_conf(conf);
7464         mddev->private = NULL;
7465         pr_warn("md/raid:%s: failed to run raid set.\n", mdname(mddev));
7466         return -EIO;
7467 }
7468
7469 static void raid5_free(struct mddev *mddev, void *priv)
7470 {
7471         struct r5conf *conf = priv;
7472
7473         free_conf(conf);
7474         mddev->to_remove = &raid5_attrs_group;
7475 }
7476
7477 static void raid5_status(struct seq_file *seq, struct mddev *mddev)
7478 {
7479         struct r5conf *conf = mddev->private;
7480         int i;
7481
7482         seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level,
7483                 conf->chunk_sectors / 2, mddev->layout);
7484         seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded);
7485         rcu_read_lock();
7486         for (i = 0; i < conf->raid_disks; i++) {
7487                 struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev);
7488                 seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_");
7489         }
7490         rcu_read_unlock();
7491         seq_printf (seq, "]");
7492 }
7493
7494 static void print_raid5_conf (struct r5conf *conf)
7495 {
7496         int i;
7497         struct disk_info *tmp;
7498
7499         pr_debug("RAID conf printout:\n");
7500         if (!conf) {
7501                 pr_debug("(conf==NULL)\n");
7502                 return;
7503         }
7504         pr_debug(" --- level:%d rd:%d wd:%d\n", conf->level,
7505                conf->raid_disks,
7506                conf->raid_disks - conf->mddev->degraded);
7507
7508         for (i = 0; i < conf->raid_disks; i++) {
7509                 char b[BDEVNAME_SIZE];
7510                 tmp = conf->disks + i;
7511                 if (tmp->rdev)
7512                         pr_debug(" disk %d, o:%d, dev:%s\n",
7513                                i, !test_bit(Faulty, &tmp->rdev->flags),
7514                                bdevname(tmp->rdev->bdev, b));
7515         }
7516 }
7517
7518 static int raid5_spare_active(struct mddev *mddev)
7519 {
7520         int i;
7521         struct r5conf *conf = mddev->private;
7522         struct disk_info *tmp;
7523         int count = 0;
7524         unsigned long flags;
7525
7526         for (i = 0; i < conf->raid_disks; i++) {
7527                 tmp = conf->disks + i;
7528                 if (tmp->replacement
7529                     && tmp->replacement->recovery_offset == MaxSector
7530                     && !test_bit(Faulty, &tmp->replacement->flags)
7531                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
7532                         /* Replacement has just become active. */
7533                         if (!tmp->rdev
7534                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
7535                                 count++;
7536                         if (tmp->rdev) {
7537                                 /* Replaced device not technically faulty,
7538                                  * but we need to be sure it gets removed
7539                                  * and never re-added.
7540                                  */
7541                                 set_bit(Faulty, &tmp->rdev->flags);
7542                                 sysfs_notify_dirent_safe(
7543                                         tmp->rdev->sysfs_state);
7544                         }
7545                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
7546                 } else if (tmp->rdev
7547                     && tmp->rdev->recovery_offset == MaxSector
7548                     && !test_bit(Faulty, &tmp->rdev->flags)
7549                     && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
7550                         count++;
7551                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
7552                 }
7553         }
7554         spin_lock_irqsave(&conf->device_lock, flags);
7555         mddev->degraded = raid5_calc_degraded(conf);
7556         spin_unlock_irqrestore(&conf->device_lock, flags);
7557         print_raid5_conf(conf);
7558         return count;
7559 }
7560
7561 static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
7562 {
7563         struct r5conf *conf = mddev->private;
7564         int err = 0;
7565         int number = rdev->raid_disk;
7566         struct md_rdev **rdevp;
7567         struct disk_info *p = conf->disks + number;
7568
7569         print_raid5_conf(conf);
7570         if (test_bit(Journal, &rdev->flags) && conf->log) {
7571                 /*
7572                  * we can't wait pending write here, as this is called in
7573                  * raid5d, wait will deadlock.
7574                  * neilb: there is no locking about new writes here,
7575                  * so this cannot be safe.
7576                  */
7577                 if (atomic_read(&conf->active_stripes) ||
7578                     atomic_read(&conf->r5c_cached_full_stripes) ||
7579                     atomic_read(&conf->r5c_cached_partial_stripes)) {
7580                         return -EBUSY;
7581                 }
7582                 log_exit(conf);
7583                 return 0;
7584         }
7585         if (rdev == p->rdev)
7586                 rdevp = &p->rdev;
7587         else if (rdev == p->replacement)
7588                 rdevp = &p->replacement;
7589         else
7590                 return 0;
7591
7592         if (number >= conf->raid_disks &&
7593             conf->reshape_progress == MaxSector)
7594                 clear_bit(In_sync, &rdev->flags);
7595
7596         if (test_bit(In_sync, &rdev->flags) ||
7597             atomic_read(&rdev->nr_pending)) {
7598                 err = -EBUSY;
7599                 goto abort;
7600         }
7601         /* Only remove non-faulty devices if recovery
7602          * isn't possible.
7603          */
7604         if (!test_bit(Faulty, &rdev->flags) &&
7605             mddev->recovery_disabled != conf->recovery_disabled &&
7606             !has_failed(conf) &&
7607             (!p->replacement || p->replacement == rdev) &&
7608             number < conf->raid_disks) {
7609                 err = -EBUSY;
7610                 goto abort;
7611         }
7612         *rdevp = NULL;
7613         if (!test_bit(RemoveSynchronized, &rdev->flags)) {
7614                 synchronize_rcu();
7615                 if (atomic_read(&rdev->nr_pending)) {
7616                         /* lost the race, try later */
7617                         err = -EBUSY;
7618                         *rdevp = rdev;
7619                 }
7620         }
7621         if (!err) {
7622                 err = log_modify(conf, rdev, false);
7623                 if (err)
7624                         goto abort;
7625         }
7626         if (p->replacement) {
7627                 /* We must have just cleared 'rdev' */
7628                 p->rdev = p->replacement;
7629                 clear_bit(Replacement, &p->replacement->flags);
7630                 smp_mb(); /* Make sure other CPUs may see both as identical
7631                            * but will never see neither - if they are careful
7632                            */
7633                 p->replacement = NULL;
7634
7635                 if (!err)
7636                         err = log_modify(conf, p->rdev, true);
7637         }
7638
7639         clear_bit(WantReplacement, &rdev->flags);
7640 abort:
7641
7642         print_raid5_conf(conf);
7643         return err;
7644 }
7645
7646 static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
7647 {
7648         struct r5conf *conf = mddev->private;
7649         int err = -EEXIST;
7650         int disk;
7651         struct disk_info *p;
7652         int first = 0;
7653         int last = conf->raid_disks - 1;
7654
7655         if (test_bit(Journal, &rdev->flags)) {
7656                 if (conf->log)
7657                         return -EBUSY;
7658
7659                 rdev->raid_disk = 0;
7660                 /*
7661                  * The array is in readonly mode if journal is missing, so no
7662                  * write requests running. We should be safe
7663                  */
7664                 log_init(conf, rdev, false);
7665                 return 0;
7666         }
7667         if (mddev->recovery_disabled == conf->recovery_disabled)
7668                 return -EBUSY;
7669
7670         if (rdev->saved_raid_disk < 0 && has_failed(conf))
7671                 /* no point adding a device */
7672                 return -EINVAL;
7673
7674         if (rdev->raid_disk >= 0)
7675                 first = last = rdev->raid_disk;
7676
7677         /*
7678          * find the disk ... but prefer rdev->saved_raid_disk
7679          * if possible.
7680          */
7681         if (rdev->saved_raid_disk >= 0 &&
7682             rdev->saved_raid_disk >= first &&
7683             conf->disks[rdev->saved_raid_disk].rdev == NULL)
7684                 first = rdev->saved_raid_disk;
7685
7686         for (disk = first; disk <= last; disk++) {
7687                 p = conf->disks + disk;
7688                 if (p->rdev == NULL) {
7689                         clear_bit(In_sync, &rdev->flags);
7690                         rdev->raid_disk = disk;
7691                         if (rdev->saved_raid_disk != disk)
7692                                 conf->fullsync = 1;
7693                         rcu_assign_pointer(p->rdev, rdev);
7694
7695                         err = log_modify(conf, rdev, true);
7696
7697                         goto out;
7698                 }
7699         }
7700         for (disk = first; disk <= last; disk++) {
7701                 p = conf->disks + disk;
7702                 if (test_bit(WantReplacement, &p->rdev->flags) &&
7703                     p->replacement == NULL) {
7704                         clear_bit(In_sync, &rdev->flags);
7705                         set_bit(Replacement, &rdev->flags);
7706                         rdev->raid_disk = disk;
7707                         err = 0;
7708                         conf->fullsync = 1;
7709                         rcu_assign_pointer(p->replacement, rdev);
7710                         break;
7711                 }
7712         }
7713 out:
7714         print_raid5_conf(conf);
7715         return err;
7716 }
7717
7718 static int raid5_resize(struct mddev *mddev, sector_t sectors)
7719 {
7720         /* no resync is happening, and there is enough space
7721          * on all devices, so we can resize.
7722          * We need to make sure resync covers any new space.
7723          * If the array is shrinking we should possibly wait until
7724          * any io in the removed space completes, but it hardly seems
7725          * worth it.
7726          */
7727         sector_t newsize;
7728         struct r5conf *conf = mddev->private;
7729
7730         if (conf->log || raid5_has_ppl(conf))
7731                 return -EINVAL;
7732         sectors &= ~((sector_t)conf->chunk_sectors - 1);
7733         newsize = raid5_size(mddev, sectors, mddev->raid_disks);
7734         if (mddev->external_size &&
7735             mddev->array_sectors > newsize)
7736                 return -EINVAL;
7737         if (mddev->bitmap) {
7738                 int ret = bitmap_resize(mddev->bitmap, sectors, 0, 0);
7739                 if (ret)
7740                         return ret;
7741         }
7742         md_set_array_sectors(mddev, newsize);
7743         if (sectors > mddev->dev_sectors &&
7744             mddev->recovery_cp > mddev->dev_sectors) {
7745                 mddev->recovery_cp = mddev->dev_sectors;
7746                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
7747         }
7748         mddev->dev_sectors = sectors;
7749         mddev->resync_max_sectors = sectors;
7750         return 0;
7751 }
7752
7753 static int check_stripe_cache(struct mddev *mddev)
7754 {
7755         /* Can only proceed if there are plenty of stripe_heads.
7756          * We need a minimum of one full stripe,, and for sensible progress
7757          * it is best to have about 4 times that.
7758          * If we require 4 times, then the default 256 4K stripe_heads will
7759          * allow for chunk sizes up to 256K, which is probably OK.
7760          * If the chunk size is greater, user-space should request more
7761          * stripe_heads first.
7762          */
7763         struct r5conf *conf = mddev->private;
7764         if (((mddev->chunk_sectors << 9) / STRIPE_SIZE) * 4
7765             > conf->min_nr_stripes ||
7766             ((mddev->new_chunk_sectors << 9) / STRIPE_SIZE) * 4
7767             > conf->min_nr_stripes) {
7768                 pr_warn("md/raid:%s: reshape: not enough stripes.  Needed %lu\n",
7769                         mdname(mddev),
7770                         ((max(mddev->chunk_sectors, mddev->new_chunk_sectors) << 9)
7771                          / STRIPE_SIZE)*4);
7772                 return 0;
7773         }
7774         return 1;
7775 }
7776
7777 static int check_reshape(struct mddev *mddev)
7778 {
7779         struct r5conf *conf = mddev->private;
7780
7781         if (conf->log || raid5_has_ppl(conf))
7782                 return -EINVAL;
7783         if (mddev->delta_disks == 0 &&
7784             mddev->new_layout == mddev->layout &&
7785             mddev->new_chunk_sectors == mddev->chunk_sectors)
7786                 return 0; /* nothing to do */
7787         if (has_failed(conf))
7788                 return -EINVAL;
7789         if (mddev->delta_disks < 0 && mddev->reshape_position == MaxSector) {
7790                 /* We might be able to shrink, but the devices must
7791                  * be made bigger first.
7792                  * For raid6, 4 is the minimum size.
7793                  * Otherwise 2 is the minimum
7794                  */
7795                 int min = 2;
7796                 if (mddev->level == 6)
7797                         min = 4;
7798                 if (mddev->raid_disks + mddev->delta_disks < min)
7799                         return -EINVAL;
7800         }
7801
7802         if (!check_stripe_cache(mddev))
7803                 return -ENOSPC;
7804
7805         if (mddev->new_chunk_sectors > mddev->chunk_sectors ||
7806             mddev->delta_disks > 0)
7807                 if (resize_chunks(conf,
7808                                   conf->previous_raid_disks
7809                                   + max(0, mddev->delta_disks),
7810                                   max(mddev->new_chunk_sectors,
7811                                       mddev->chunk_sectors)
7812                             ) < 0)
7813                         return -ENOMEM;
7814
7815         if (conf->previous_raid_disks + mddev->delta_disks <= conf->pool_size)
7816                 return 0; /* never bother to shrink */
7817         return resize_stripes(conf, (conf->previous_raid_disks
7818                                      + mddev->delta_disks));
7819 }
7820
7821 static int raid5_start_reshape(struct mddev *mddev)
7822 {
7823         struct r5conf *conf = mddev->private;
7824         struct md_rdev *rdev;
7825         int spares = 0;
7826         unsigned long flags;
7827
7828         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
7829                 return -EBUSY;
7830
7831         if (!check_stripe_cache(mddev))
7832                 return -ENOSPC;
7833
7834         if (has_failed(conf))
7835                 return -EINVAL;
7836
7837         rdev_for_each(rdev, mddev) {
7838                 if (!test_bit(In_sync, &rdev->flags)
7839                     && !test_bit(Faulty, &rdev->flags))
7840                         spares++;
7841         }
7842
7843         if (spares - mddev->degraded < mddev->delta_disks - conf->max_degraded)
7844                 /* Not enough devices even to make a degraded array
7845                  * of that size
7846                  */
7847                 return -EINVAL;
7848
7849         /* Refuse to reduce size of the array.  Any reductions in
7850          * array size must be through explicit setting of array_size
7851          * attribute.
7852          */
7853         if (raid5_size(mddev, 0, conf->raid_disks + mddev->delta_disks)
7854             < mddev->array_sectors) {
7855                 pr_warn("md/raid:%s: array size must be reduced before number of disks\n",
7856                         mdname(mddev));
7857                 return -EINVAL;
7858         }
7859
7860         atomic_set(&conf->reshape_stripes, 0);
7861         spin_lock_irq(&conf->device_lock);
7862         write_seqcount_begin(&conf->gen_lock);
7863         conf->previous_raid_disks = conf->raid_disks;
7864         conf->raid_disks += mddev->delta_disks;
7865         conf->prev_chunk_sectors = conf->chunk_sectors;
7866         conf->chunk_sectors = mddev->new_chunk_sectors;
7867         conf->prev_algo = conf->algorithm;
7868         conf->algorithm = mddev->new_layout;
7869         conf->generation++;
7870         /* Code that selects data_offset needs to see the generation update
7871          * if reshape_progress has been set - so a memory barrier needed.
7872          */
7873         smp_mb();
7874         if (mddev->reshape_backwards)
7875                 conf->reshape_progress = raid5_size(mddev, 0, 0);
7876         else
7877                 conf->reshape_progress = 0;
7878         conf->reshape_safe = conf->reshape_progress;
7879         write_seqcount_end(&conf->gen_lock);
7880         spin_unlock_irq(&conf->device_lock);
7881
7882         /* Now make sure any requests that proceeded on the assumption
7883          * the reshape wasn't running - like Discard or Read - have
7884          * completed.
7885          */
7886         mddev_suspend(mddev);
7887         mddev_resume(mddev);
7888
7889         /* Add some new drives, as many as will fit.
7890          * We know there are enough to make the newly sized array work.
7891          * Don't add devices if we are reducing the number of
7892          * devices in the array.  This is because it is not possible
7893          * to correctly record the "partially reconstructed" state of
7894          * such devices during the reshape and confusion could result.
7895          */
7896         if (mddev->delta_disks >= 0) {
7897                 rdev_for_each(rdev, mddev)
7898                         if (rdev->raid_disk < 0 &&
7899                             !test_bit(Faulty, &rdev->flags)) {
7900                                 if (raid5_add_disk(mddev, rdev) == 0) {
7901                                         if (rdev->raid_disk
7902                                             >= conf->previous_raid_disks)
7903                                                 set_bit(In_sync, &rdev->flags);
7904                                         else
7905                                                 rdev->recovery_offset = 0;
7906
7907                                         if (sysfs_link_rdev(mddev, rdev))
7908                                                 /* Failure here is OK */;
7909                                 }
7910                         } else if (rdev->raid_disk >= conf->previous_raid_disks
7911                                    && !test_bit(Faulty, &rdev->flags)) {
7912                                 /* This is a spare that was manually added */
7913                                 set_bit(In_sync, &rdev->flags);
7914                         }
7915
7916                 /* When a reshape changes the number of devices,
7917                  * ->degraded is measured against the larger of the
7918                  * pre and post number of devices.
7919                  */
7920                 spin_lock_irqsave(&conf->device_lock, flags);
7921                 mddev->degraded = raid5_calc_degraded(conf);
7922                 spin_unlock_irqrestore(&conf->device_lock, flags);
7923         }
7924         mddev->raid_disks = conf->raid_disks;
7925         mddev->reshape_position = conf->reshape_progress;
7926         set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7927
7928         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
7929         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
7930         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
7931         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
7932         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
7933         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
7934                                                 "reshape");
7935         if (!mddev->sync_thread) {
7936                 mddev->recovery = 0;
7937                 spin_lock_irq(&conf->device_lock);
7938                 write_seqcount_begin(&conf->gen_lock);
7939                 mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;
7940                 mddev->new_chunk_sectors =
7941                         conf->chunk_sectors = conf->prev_chunk_sectors;
7942                 mddev->new_layout = conf->algorithm = conf->prev_algo;
7943                 rdev_for_each(rdev, mddev)
7944                         rdev->new_data_offset = rdev->data_offset;
7945                 smp_wmb();
7946                 conf->generation --;
7947                 conf->reshape_progress = MaxSector;
7948                 mddev->reshape_position = MaxSector;
7949                 write_seqcount_end(&conf->gen_lock);
7950                 spin_unlock_irq(&conf->device_lock);
7951                 return -EAGAIN;
7952         }
7953         conf->reshape_checkpoint = jiffies;
7954         md_wakeup_thread(mddev->sync_thread);
7955         md_new_event(mddev);
7956         return 0;
7957 }
7958
7959 /* This is called from the reshape thread and should make any
7960  * changes needed in 'conf'
7961  */
7962 static void end_reshape(struct r5conf *conf)
7963 {
7964
7965         if (!test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery)) {
7966                 struct md_rdev *rdev;
7967
7968                 spin_lock_irq(&conf->device_lock);
7969                 conf->previous_raid_disks = conf->raid_disks;
7970                 md_finish_reshape(conf->mddev);
7971                 smp_wmb();
7972                 conf->reshape_progress = MaxSector;
7973                 conf->mddev->reshape_position = MaxSector;
7974                 rdev_for_each(rdev, conf->mddev)
7975                         if (rdev->raid_disk >= 0 &&
7976                             !test_bit(Journal, &rdev->flags) &&
7977                             !test_bit(In_sync, &rdev->flags))
7978                                 rdev->recovery_offset = MaxSector;
7979                 spin_unlock_irq(&conf->device_lock);
7980                 wake_up(&conf->wait_for_overlap);
7981
7982                 /* read-ahead size must cover two whole stripes, which is
7983                  * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
7984                  */
7985                 if (conf->mddev->queue) {
7986                         int data_disks = conf->raid_disks - conf->max_degraded;
7987                         int stripe = data_disks * ((conf->chunk_sectors << 9)
7988                                                    / PAGE_SIZE);
7989                         if (conf->mddev->queue->backing_dev_info->ra_pages < 2 * stripe)
7990                                 conf->mddev->queue->backing_dev_info->ra_pages = 2 * stripe;
7991                 }
7992         }
7993 }
7994
7995 /* This is called from the raid5d thread with mddev_lock held.
7996  * It makes config changes to the device.
7997  */
7998 static void raid5_finish_reshape(struct mddev *mddev)
7999 {
8000         struct r5conf *conf = mddev->private;
8001
8002         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
8003
8004                 if (mddev->delta_disks > 0) {
8005                         md_set_array_sectors(mddev, raid5_size(mddev, 0, 0));
8006                         if (mddev->queue) {
8007                                 set_capacity(mddev->gendisk, mddev->array_sectors);
8008                                 revalidate_disk(mddev->gendisk);
8009                         }
8010                 } else {
8011                         int d;
8012                         spin_lock_irq(&conf->device_lock);
8013                         mddev->degraded = raid5_calc_degraded(conf);
8014                         spin_unlock_irq(&conf->device_lock);
8015                         for (d = conf->raid_disks ;
8016                              d < conf->raid_disks - mddev->delta_disks;
8017                              d++) {
8018                                 struct md_rdev *rdev = conf->disks[d].rdev;
8019                                 if (rdev)
8020                                         clear_bit(In_sync, &rdev->flags);
8021                                 rdev = conf->disks[d].replacement;
8022                                 if (rdev)
8023                                         clear_bit(In_sync, &rdev->flags);
8024                         }
8025                 }
8026                 mddev->layout = conf->algorithm;
8027                 mddev->chunk_sectors = conf->chunk_sectors;
8028                 mddev->reshape_position = MaxSector;
8029                 mddev->delta_disks = 0;
8030                 mddev->reshape_backwards = 0;
8031         }
8032 }
8033
8034 static void raid5_quiesce(struct mddev *mddev, int quiesce)
8035 {
8036         struct r5conf *conf = mddev->private;
8037
8038         if (quiesce) {
8039                 /* stop all writes */
8040                 lock_all_device_hash_locks_irq(conf);
8041                 /* '2' tells resync/reshape to pause so that all
8042                  * active stripes can drain
8043                  */
8044                 r5c_flush_cache(conf, INT_MAX);
8045                 conf->quiesce = 2;
8046                 wait_event_cmd(conf->wait_for_quiescent,
8047                                     atomic_read(&conf->active_stripes) == 0 &&
8048                                     atomic_read(&conf->active_aligned_reads) == 0,
8049                                     unlock_all_device_hash_locks_irq(conf),
8050                                     lock_all_device_hash_locks_irq(conf));
8051                 conf->quiesce = 1;
8052                 unlock_all_device_hash_locks_irq(conf);
8053                 /* allow reshape to continue */
8054                 wake_up(&conf->wait_for_overlap);
8055         } else {
8056                 /* re-enable writes */
8057                 lock_all_device_hash_locks_irq(conf);
8058                 conf->quiesce = 0;
8059                 wake_up(&conf->wait_for_quiescent);
8060                 wake_up(&conf->wait_for_overlap);
8061                 unlock_all_device_hash_locks_irq(conf);
8062         }
8063         log_quiesce(conf, quiesce);
8064 }
8065
8066 static void *raid45_takeover_raid0(struct mddev *mddev, int level)
8067 {
8068         struct r0conf *raid0_conf = mddev->private;
8069         sector_t sectors;
8070
8071         /* for raid0 takeover only one zone is supported */
8072         if (raid0_conf->nr_strip_zones > 1) {
8073                 pr_warn("md/raid:%s: cannot takeover raid0 with more than one zone.\n",
8074                         mdname(mddev));
8075                 return ERR_PTR(-EINVAL);
8076         }
8077
8078         sectors = raid0_conf->strip_zone[0].zone_end;
8079         sector_div(sectors, raid0_conf->strip_zone[0].nb_dev);
8080         mddev->dev_sectors = sectors;
8081         mddev->new_level = level;
8082         mddev->new_layout = ALGORITHM_PARITY_N;
8083         mddev->new_chunk_sectors = mddev->chunk_sectors;
8084         mddev->raid_disks += 1;
8085         mddev->delta_disks = 1;
8086         /* make sure it will be not marked as dirty */
8087         mddev->recovery_cp = MaxSector;
8088
8089         return setup_conf(mddev);
8090 }
8091
8092 static void *raid5_takeover_raid1(struct mddev *mddev)
8093 {
8094         int chunksect;
8095         void *ret;
8096
8097         if (mddev->raid_disks != 2 ||
8098             mddev->degraded > 1)
8099                 return ERR_PTR(-EINVAL);
8100
8101         /* Should check if there are write-behind devices? */
8102
8103         chunksect = 64*2; /* 64K by default */
8104
8105         /* The array must be an exact multiple of chunksize */
8106         while (chunksect && (mddev->array_sectors & (chunksect-1)))
8107                 chunksect >>= 1;
8108
8109         if ((chunksect<<9) < STRIPE_SIZE)
8110                 /* array size does not allow a suitable chunk size */
8111                 return ERR_PTR(-EINVAL);
8112
8113         mddev->new_level = 5;
8114         mddev->new_layout = ALGORITHM_LEFT_SYMMETRIC;
8115         mddev->new_chunk_sectors = chunksect;
8116
8117         ret = setup_conf(mddev);
8118         if (!IS_ERR(ret))
8119                 mddev_clear_unsupported_flags(mddev,
8120                         UNSUPPORTED_MDDEV_FLAGS);
8121         return ret;
8122 }
8123
8124 static void *raid5_takeover_raid6(struct mddev *mddev)
8125 {
8126         int new_layout;
8127
8128         switch (mddev->layout) {
8129         case ALGORITHM_LEFT_ASYMMETRIC_6:
8130                 new_layout = ALGORITHM_LEFT_ASYMMETRIC;
8131                 break;
8132         case ALGORITHM_RIGHT_ASYMMETRIC_6:
8133                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
8134                 break;
8135         case ALGORITHM_LEFT_SYMMETRIC_6:
8136                 new_layout = ALGORITHM_LEFT_SYMMETRIC;
8137                 break;
8138         case ALGORITHM_RIGHT_SYMMETRIC_6:
8139                 new_layout = ALGORITHM_RIGHT_SYMMETRIC;
8140                 break;
8141         case ALGORITHM_PARITY_0_6:
8142                 new_layout = ALGORITHM_PARITY_0;
8143                 break;
8144         case ALGORITHM_PARITY_N:
8145                 new_layout = ALGORITHM_PARITY_N;
8146                 break;
8147         default:
8148                 return ERR_PTR(-EINVAL);
8149         }
8150         mddev->new_level = 5;
8151         mddev->new_layout = new_layout;
8152         mddev->delta_disks = -1;
8153         mddev->raid_disks -= 1;
8154         return setup_conf(mddev);
8155 }
8156
8157 static int raid5_check_reshape(struct mddev *mddev)
8158 {
8159         /* For a 2-drive array, the layout and chunk size can be changed
8160          * immediately as not restriping is needed.
8161          * For larger arrays we record the new value - after validation
8162          * to be used by a reshape pass.
8163          */
8164         struct r5conf *conf = mddev->private;
8165         int new_chunk = mddev->new_chunk_sectors;
8166
8167         if (mddev->new_layout >= 0 && !algorithm_valid_raid5(mddev->new_layout))
8168                 return -EINVAL;
8169         if (new_chunk > 0) {
8170                 if (!is_power_of_2(new_chunk))
8171                         return -EINVAL;
8172                 if (new_chunk < (PAGE_SIZE>>9))
8173                         return -EINVAL;
8174                 if (mddev->array_sectors & (new_chunk-1))
8175                         /* not factor of array size */
8176                         return -EINVAL;
8177         }
8178
8179         /* They look valid */
8180
8181         if (mddev->raid_disks == 2) {
8182                 /* can make the change immediately */
8183                 if (mddev->new_layout >= 0) {
8184                         conf->algorithm = mddev->new_layout;
8185                         mddev->layout = mddev->new_layout;
8186                 }
8187                 if (new_chunk > 0) {
8188                         conf->chunk_sectors = new_chunk ;
8189                         mddev->chunk_sectors = new_chunk;
8190                 }
8191                 set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
8192                 md_wakeup_thread(mddev->thread);
8193         }
8194         return check_reshape(mddev);
8195 }
8196
8197 static int raid6_check_reshape(struct mddev *mddev)
8198 {
8199         int new_chunk = mddev->new_chunk_sectors;
8200
8201         if (mddev->new_layout >= 0 && !algorithm_valid_raid6(mddev->new_layout))
8202                 return -EINVAL;
8203         if (new_chunk > 0) {
8204                 if (!is_power_of_2(new_chunk))
8205                         return -EINVAL;
8206                 if (new_chunk < (PAGE_SIZE >> 9))
8207                         return -EINVAL;
8208                 if (mddev->array_sectors & (new_chunk-1))
8209                         /* not factor of array size */
8210                         return -EINVAL;
8211         }
8212
8213         /* They look valid */
8214         return check_reshape(mddev);
8215 }
8216
8217 static void *raid5_takeover(struct mddev *mddev)
8218 {
8219         /* raid5 can take over:
8220          *  raid0 - if there is only one strip zone - make it a raid4 layout
8221          *  raid1 - if there are two drives.  We need to know the chunk size
8222          *  raid4 - trivial - just use a raid4 layout.
8223          *  raid6 - Providing it is a *_6 layout
8224          */
8225         if (mddev->level == 0)
8226                 return raid45_takeover_raid0(mddev, 5);
8227         if (mddev->level == 1)
8228                 return raid5_takeover_raid1(mddev);
8229         if (mddev->level == 4) {
8230                 mddev->new_layout = ALGORITHM_PARITY_N;
8231                 mddev->new_level = 5;
8232                 return setup_conf(mddev);
8233         }
8234         if (mddev->level == 6)
8235                 return raid5_takeover_raid6(mddev);
8236
8237         return ERR_PTR(-EINVAL);
8238 }
8239
8240 static void *raid4_takeover(struct mddev *mddev)
8241 {
8242         /* raid4 can take over:
8243          *  raid0 - if there is only one strip zone
8244          *  raid5 - if layout is right
8245          */
8246         if (mddev->level == 0)
8247                 return raid45_takeover_raid0(mddev, 4);
8248         if (mddev->level == 5 &&
8249             mddev->layout == ALGORITHM_PARITY_N) {
8250                 mddev->new_layout = 0;
8251                 mddev->new_level = 4;
8252                 return setup_conf(mddev);
8253         }
8254         return ERR_PTR(-EINVAL);
8255 }
8256
8257 static struct md_personality raid5_personality;
8258
8259 static void *raid6_takeover(struct mddev *mddev)
8260 {
8261         /* Currently can only take over a raid5.  We map the
8262          * personality to an equivalent raid6 personality
8263          * with the Q block at the end.
8264          */
8265         int new_layout;
8266
8267         if (mddev->pers != &raid5_personality)
8268                 return ERR_PTR(-EINVAL);
8269         if (mddev->degraded > 1)
8270                 return ERR_PTR(-EINVAL);
8271         if (mddev->raid_disks > 253)
8272                 return ERR_PTR(-EINVAL);
8273         if (mddev->raid_disks < 3)
8274                 return ERR_PTR(-EINVAL);
8275
8276         switch (mddev->layout) {
8277         case ALGORITHM_LEFT_ASYMMETRIC:
8278                 new_layout = ALGORITHM_LEFT_ASYMMETRIC_6;
8279                 break;
8280         case ALGORITHM_RIGHT_ASYMMETRIC:
8281                 new_layout = ALGORITHM_RIGHT_ASYMMETRIC_6;
8282                 break;
8283         case ALGORITHM_LEFT_SYMMETRIC:
8284                 new_layout = ALGORITHM_LEFT_SYMMETRIC_6;
8285                 break;
8286         case ALGORITHM_RIGHT_SYMMETRIC:
8287                 new_layout = ALGORITHM_RIGHT_SYMMETRIC_6;
8288                 break;
8289         case ALGORITHM_PARITY_0:
8290                 new_layout = ALGORITHM_PARITY_0_6;
8291                 break;
8292         case ALGORITHM_PARITY_N:
8293                 new_layout = ALGORITHM_PARITY_N;
8294                 break;
8295         default:
8296                 return ERR_PTR(-EINVAL);
8297         }
8298         mddev->new_level = 6;
8299         mddev->new_layout = new_layout;
8300         mddev->delta_disks = 1;
8301         mddev->raid_disks += 1;
8302         return setup_conf(mddev);
8303 }
8304
8305 static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
8306 {
8307         struct r5conf *conf;
8308         int err;
8309
8310         err = mddev_lock(mddev);
8311         if (err)
8312                 return err;
8313         conf = mddev->private;
8314         if (!conf) {
8315                 mddev_unlock(mddev);
8316                 return -ENODEV;
8317         }
8318
8319         if (strncmp(buf, "ppl", 3) == 0) {
8320                 /* ppl only works with RAID 5 */
8321                 if (!raid5_has_ppl(conf) && conf->level == 5) {
8322                         err = log_init(conf, NULL, true);
8323                         if (!err) {
8324                                 err = resize_stripes(conf, conf->pool_size);
8325                                 if (err)
8326                                         log_exit(conf);
8327                         }
8328                 } else
8329                         err = -EINVAL;
8330         } else if (strncmp(buf, "resync", 6) == 0) {
8331                 if (raid5_has_ppl(conf)) {
8332                         mddev_suspend(mddev);
8333                         log_exit(conf);
8334                         mddev_resume(mddev);
8335                         err = resize_stripes(conf, conf->pool_size);
8336                 } else if (test_bit(MD_HAS_JOURNAL, &conf->mddev->flags) &&
8337                            r5l_log_disk_error(conf)) {
8338                         bool journal_dev_exists = false;
8339                         struct md_rdev *rdev;
8340
8341                         rdev_for_each(rdev, mddev)
8342                                 if (test_bit(Journal, &rdev->flags)) {
8343                                         journal_dev_exists = true;
8344                                         break;
8345                                 }
8346
8347                         if (!journal_dev_exists) {
8348                                 mddev_suspend(mddev);
8349                                 clear_bit(MD_HAS_JOURNAL, &mddev->flags);
8350                                 mddev_resume(mddev);
8351                         } else  /* need remove journal device first */
8352                                 err = -EBUSY;
8353                 } else
8354                         err = -EINVAL;
8355         } else {
8356                 err = -EINVAL;
8357         }
8358
8359         if (!err)
8360                 md_update_sb(mddev, 1);
8361
8362         mddev_unlock(mddev);
8363
8364         return err;
8365 }
8366
8367 static int raid5_start(struct mddev *mddev)
8368 {
8369         struct r5conf *conf = mddev->private;
8370
8371         return r5l_start(conf->log);
8372 }
8373
8374 static struct md_personality raid6_personality =
8375 {
8376         .name           = "raid6",
8377         .level          = 6,
8378         .owner          = THIS_MODULE,
8379         .make_request   = raid5_make_request,
8380         .run            = raid5_run,
8381         .start          = raid5_start,
8382         .free           = raid5_free,
8383         .status         = raid5_status,
8384         .error_handler  = raid5_error,
8385         .hot_add_disk   = raid5_add_disk,
8386         .hot_remove_disk= raid5_remove_disk,
8387         .spare_active   = raid5_spare_active,
8388         .sync_request   = raid5_sync_request,
8389         .resize         = raid5_resize,
8390         .size           = raid5_size,
8391         .check_reshape  = raid6_check_reshape,
8392         .start_reshape  = raid5_start_reshape,
8393         .finish_reshape = raid5_finish_reshape,
8394         .quiesce        = raid5_quiesce,
8395         .takeover       = raid6_takeover,
8396         .congested      = raid5_congested,
8397         .change_consistency_policy = raid5_change_consistency_policy,
8398 };
8399 static struct md_personality raid5_personality =
8400 {
8401         .name           = "raid5",
8402         .level          = 5,
8403         .owner          = THIS_MODULE,
8404         .make_request   = raid5_make_request,
8405         .run            = raid5_run,
8406         .start          = raid5_start,
8407         .free           = raid5_free,
8408         .status         = raid5_status,
8409         .error_handler  = raid5_error,
8410         .hot_add_disk   = raid5_add_disk,
8411         .hot_remove_disk= raid5_remove_disk,
8412         .spare_active   = raid5_spare_active,
8413         .sync_request   = raid5_sync_request,
8414         .resize         = raid5_resize,
8415         .size           = raid5_size,
8416         .check_reshape  = raid5_check_reshape,
8417         .start_reshape  = raid5_start_reshape,
8418         .finish_reshape = raid5_finish_reshape,
8419         .quiesce        = raid5_quiesce,
8420         .takeover       = raid5_takeover,
8421         .congested      = raid5_congested,
8422         .change_consistency_policy = raid5_change_consistency_policy,
8423 };
8424
8425 static struct md_personality raid4_personality =
8426 {
8427         .name           = "raid4",
8428         .level          = 4,
8429         .owner          = THIS_MODULE,
8430         .make_request   = raid5_make_request,
8431         .run            = raid5_run,
8432         .start          = raid5_start,
8433         .free           = raid5_free,
8434         .status         = raid5_status,
8435         .error_handler  = raid5_error,
8436         .hot_add_disk   = raid5_add_disk,
8437         .hot_remove_disk= raid5_remove_disk,
8438         .spare_active   = raid5_spare_active,
8439         .sync_request   = raid5_sync_request,
8440         .resize         = raid5_resize,
8441         .size           = raid5_size,
8442         .check_reshape  = raid5_check_reshape,
8443         .start_reshape  = raid5_start_reshape,
8444         .finish_reshape = raid5_finish_reshape,
8445         .quiesce        = raid5_quiesce,
8446         .takeover       = raid4_takeover,
8447         .congested      = raid5_congested,
8448         .change_consistency_policy = raid5_change_consistency_policy,
8449 };
8450
8451 static int __init raid5_init(void)
8452 {
8453         int ret;
8454
8455         raid5_wq = alloc_workqueue("raid5wq",
8456                 WQ_UNBOUND|WQ_MEM_RECLAIM|WQ_CPU_INTENSIVE|WQ_SYSFS, 0);
8457         if (!raid5_wq)
8458                 return -ENOMEM;
8459
8460         ret = cpuhp_setup_state_multi(CPUHP_MD_RAID5_PREPARE,
8461                                       "md/raid5:prepare",
8462                                       raid456_cpu_up_prepare,
8463                                       raid456_cpu_dead);
8464         if (ret) {
8465                 destroy_workqueue(raid5_wq);
8466                 return ret;
8467         }
8468         register_md_personality(&raid6_personality);
8469         register_md_personality(&raid5_personality);
8470         register_md_personality(&raid4_personality);
8471         return 0;
8472 }
8473
8474 static void raid5_exit(void)
8475 {
8476         unregister_md_personality(&raid6_personality);
8477         unregister_md_personality(&raid5_personality);
8478         unregister_md_personality(&raid4_personality);
8479         cpuhp_remove_multi_state(CPUHP_MD_RAID5_PREPARE);
8480         destroy_workqueue(raid5_wq);
8481 }
8482
8483 module_init(raid5_init);
8484 module_exit(raid5_exit);
8485 MODULE_LICENSE("GPL");
8486 MODULE_DESCRIPTION("RAID4/5/6 (striping with parity) personality for MD");
8487 MODULE_ALIAS("md-personality-4"); /* RAID5 */
8488 MODULE_ALIAS("md-raid5");
8489 MODULE_ALIAS("md-raid4");
8490 MODULE_ALIAS("md-level-5");
8491 MODULE_ALIAS("md-level-4");
8492 MODULE_ALIAS("md-personality-8"); /* RAID6 */
8493 MODULE_ALIAS("md-raid6");
8494 MODULE_ALIAS("md-level-6");
8495
8496 /* This used to be two separate modules, they were: */
8497 MODULE_ALIAS("raid5");
8498 MODULE_ALIAS("raid6");