fs/nfs/pagelist.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/fs/nfs/pagelist.c
   4  *
   5  * A set of helper functions for managing NFS read and write requests.
   6  * The main purpose of these routines is to provide support for the
   7  * coalescing of several requests into a single RPC call.
   8  *
   9  * Copyright 2000, 2001 (c) Trond Myklebust <[email protected]>
  10  *
  11  */
  12
  13 #include <linux/slab.h>
  14 #include <linux/file.h>
  15 #include <linux/sched.h>
  16 #include <linux/sunrpc/clnt.h>
  17 #include <linux/nfs.h>
  18 #include <linux/nfs3.h>
  19 #include <linux/nfs4.h>
  20 #include <linux/nfs_fs.h>
  21 #include <linux/nfs_page.h>
  22 #include <linux/nfs_mount.h>
  23 #include <linux/export.h>
  24 #include <linux/filelock.h>
  25
  26 #include "internal.h"
  27 #include "pnfs.h"
  28 #include "nfstrace.h"
  29 #include "fscache.h"
  30
  31 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  32
  33 static struct kmem_cache *nfs_page_cachep;
  34 static const struct rpc_call_ops nfs_pgio_common_ops;
  35
  36 struct nfs_page_iter_page {
  37         const struct nfs_page *req;
  38         size_t count;
  39 };
  40
  41 static void nfs_page_iter_page_init(struct nfs_page_iter_page *i,
  42                                     const struct nfs_page *req)
  43 {
  44         i->req = req;
  45         i->count = 0;
  46 }
  47
  48 static void nfs_page_iter_page_advance(struct nfs_page_iter_page *i, size_t sz)
  49 {
  50         const struct nfs_page *req = i->req;
  51         size_t tmp = i->count + sz;
  52
  53         i->count = (tmp < req->wb_bytes) ? tmp : req->wb_bytes;
  54 }
  55
  56 static struct page *nfs_page_iter_page_get(struct nfs_page_iter_page *i)
  57 {
  58         const struct nfs_page *req = i->req;
  59         struct page *page;
  60
  61         if (i->count != req->wb_bytes) {
  62                 size_t base = i->count + req->wb_pgbase;
  63                 size_t len = PAGE_SIZE - offset_in_page(base);
  64
  65                 page = nfs_page_to_page(req, base);
  66                 nfs_page_iter_page_advance(i, len);
  67                 return page;
  68         }
  69         return NULL;
  70 }
  71
  72 static struct nfs_pgio_mirror *
  73 nfs_pgio_get_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
  74 {
  75         if (desc->pg_ops->pg_get_mirror)
  76                 return desc->pg_ops->pg_get_mirror(desc, idx);
  77         return &desc->pg_mirrors[0];
  78 }
  79
  80 struct nfs_pgio_mirror *
  81 nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc)
  82 {
  83         return nfs_pgio_get_mirror(desc, desc->pg_mirror_idx);
  84 }
  85 EXPORT_SYMBOL_GPL(nfs_pgio_current_mirror);
  86
  87 static u32
  88 nfs_pgio_set_current_mirror(struct nfs_pageio_descriptor *desc, u32 idx)
  89 {
  90         if (desc->pg_ops->pg_set_mirror)
  91                 return desc->pg_ops->pg_set_mirror(desc, idx);
  92         return desc->pg_mirror_idx;
  93 }
  94
  95 void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
  96                        struct nfs_pgio_header *hdr,
  97                        void (*release)(struct nfs_pgio_header *hdr))
  98 {
  99         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 100
 101
 102         hdr->req = nfs_list_entry(mirror->pg_list.next);
 103         hdr->inode = desc->pg_inode;
 104         hdr->cred = nfs_req_openctx(hdr->req)->cred;
 105         hdr->io_start = req_offset(hdr->req);
 106         hdr->good_bytes = mirror->pg_count;
 107         hdr->io_completion = desc->pg_io_completion;
 108         hdr->dreq = desc->pg_dreq;
 109         nfs_netfs_set_pgio_header(hdr, desc);
 110         hdr->release = release;
 111         hdr->completion_ops = desc->pg_completion_ops;
 112         if (hdr->completion_ops->init_hdr)
 113                 hdr->completion_ops->init_hdr(hdr);
 114
 115         hdr->pgio_mirror_idx = desc->pg_mirror_idx;
 116 }
 117 EXPORT_SYMBOL_GPL(nfs_pgheader_init);
 118
 119 void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
 120 {
 121         unsigned int new = pos - hdr->io_start;
 122
 123         trace_nfs_pgio_error(hdr, error, pos);
 124         if (hdr->good_bytes > new) {
 125                 hdr->good_bytes = new;
 126                 clear_bit(NFS_IOHDR_EOF, &hdr->flags);
 127                 if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags))
 128                         hdr->error = error;
 129         }
 130 }
 131
 132 static inline struct nfs_page *nfs_page_alloc(void)
 133 {
 134         struct nfs_page *p =
 135                 kmem_cache_zalloc(nfs_page_cachep, nfs_io_gfp_mask());
 136         if (p)
 137                 INIT_LIST_HEAD(&p->wb_list);
 138         return p;
 139 }
 140
 141 static inline void
 142 nfs_page_free(struct nfs_page *p)
 143 {
 144         kmem_cache_free(nfs_page_cachep, p);
 145 }
 146
 147 /**
 148  * nfs_iocounter_wait - wait for i/o to complete
 149  * @l_ctx: nfs_lock_context with io_counter to use
 150  *
 151  * returns -ERESTARTSYS if interrupted by a fatal signal.
 152  * Otherwise returns 0 once the io_count hits 0.
 153  */
 154 int
 155 nfs_iocounter_wait(struct nfs_lock_context *l_ctx)
 156 {
 157         return wait_var_event_killable(&l_ctx->io_count,
 158                                        !atomic_read(&l_ctx->io_count));
 159 }
 160
 161 /**
 162  * nfs_async_iocounter_wait - wait on a rpc_waitqueue for I/O
 163  * to complete
 164  * @task: the rpc_task that should wait
 165  * @l_ctx: nfs_lock_context with io_counter to check
 166  *
 167  * Returns true if there is outstanding I/O to wait on and the
 168  * task has been put to sleep.
 169  */
 170 bool
 171 nfs_async_iocounter_wait(struct rpc_task *task, struct nfs_lock_context *l_ctx)
 172 {
 173         struct inode *inode = d_inode(l_ctx->open_context->dentry);
 174         bool ret = false;
 175
 176         if (atomic_read(&l_ctx->io_count) > 0) {
 177                 rpc_sleep_on(&NFS_SERVER(inode)->uoc_rpcwaitq, task, NULL);
 178                 ret = true;
 179         }
 180
 181         if (atomic_read(&l_ctx->io_count) == 0) {
 182                 rpc_wake_up_queued_task(&NFS_SERVER(inode)->uoc_rpcwaitq, task);
 183                 ret = false;
 184         }
 185
 186         return ret;
 187 }
 188 EXPORT_SYMBOL_GPL(nfs_async_iocounter_wait);
 189
 190 /*
 191  * nfs_page_set_headlock - set the request PG_HEADLOCK
 192  * @req: request that is to be locked
 193  *
 194  * this lock must be held when modifying req->wb_head
 195  *
 196  * return 0 on success, < 0 on error
 197  */
 198 int
 199 nfs_page_set_headlock(struct nfs_page *req)
 200 {
 201         if (!test_and_set_bit(PG_HEADLOCK, &req->wb_flags))
 202                 return 0;
 203
 204         set_bit(PG_CONTENDED1, &req->wb_flags);
 205         smp_mb__after_atomic();
 206         return wait_on_bit_lock(&req->wb_flags, PG_HEADLOCK,
 207                                 TASK_UNINTERRUPTIBLE);
 208 }
 209
 210 /*
 211  * nfs_page_clear_headlock - clear the request PG_HEADLOCK
 212  * @req: request that is to be locked
 213  */
 214 void
 215 nfs_page_clear_headlock(struct nfs_page *req)
 216 {
 217         clear_bit_unlock(PG_HEADLOCK, &req->wb_flags);
 218         smp_mb__after_atomic();
 219         if (!test_bit(PG_CONTENDED1, &req->wb_flags))
 220                 return;
 221         wake_up_bit(&req->wb_flags, PG_HEADLOCK);
 222 }
 223
 224 /*
 225  * nfs_page_group_lock - lock the head of the page group
 226  * @req: request in group that is to be locked
 227  *
 228  * this lock must be held when traversing or modifying the page
 229  * group list
 230  *
 231  * return 0 on success, < 0 on error
 232  */
 233 int
 234 nfs_page_group_lock(struct nfs_page *req)
 235 {
 236         int ret;
 237
 238         ret = nfs_page_set_headlock(req);
 239         if (ret || req->wb_head == req)
 240                 return ret;
 241         return nfs_page_set_headlock(req->wb_head);
 242 }
 243
 244 /*
 245  * nfs_page_group_unlock - unlock the head of the page group
 246  * @req: request in group that is to be unlocked
 247  */
 248 void
 249 nfs_page_group_unlock(struct nfs_page *req)
 250 {
 251         if (req != req->wb_head)
 252                 nfs_page_clear_headlock(req->wb_head);
 253         nfs_page_clear_headlock(req);
 254 }
 255
 256 /*
 257  * nfs_page_group_sync_on_bit_locked
 258  *
 259  * must be called with page group lock held
 260  */
 261 static bool
 262 nfs_page_group_sync_on_bit_locked(struct nfs_page *req, unsigned int bit)
 263 {
 264         struct nfs_page *head = req->wb_head;
 265         struct nfs_page *tmp;
 266
 267         WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_flags));
 268         WARN_ON_ONCE(test_and_set_bit(bit, &req->wb_flags));
 269
 270         tmp = req->wb_this_page;
 271         while (tmp != req) {
 272                 if (!test_bit(bit, &tmp->wb_flags))
 273                         return false;
 274                 tmp = tmp->wb_this_page;
 275         }
 276
 277         /* true! reset all bits */
 278         tmp = req;
 279         do {
 280                 clear_bit(bit, &tmp->wb_flags);
 281                 tmp = tmp->wb_this_page;
 282         } while (tmp != req);
 283
 284         return true;
 285 }
 286
 287 /*
 288  * nfs_page_group_sync_on_bit - set bit on current request, but only
 289  *   return true if the bit is set for all requests in page group
 290  * @req - request in page group
 291  * @bit - PG_* bit that is used to sync page group
 292  */
 293 bool nfs_page_group_sync_on_bit(struct nfs_page *req, unsigned int bit)
 294 {
 295         bool ret;
 296
 297         nfs_page_group_lock(req);
 298         ret = nfs_page_group_sync_on_bit_locked(req, bit);
 299         nfs_page_group_unlock(req);
 300
 301         return ret;
 302 }
 303
 304 /*
 305  * nfs_page_group_init - Initialize the page group linkage for @req
 306  * @req - a new nfs request
 307  * @prev - the previous request in page group, or NULL if @req is the first
 308  *         or only request in the group (the head).
 309  */
 310 static inline void
 311 nfs_page_group_init(struct nfs_page *req, struct nfs_page *prev)
 312 {
 313         struct inode *inode;
 314         WARN_ON_ONCE(prev == req);
 315
 316         if (!prev) {
 317                 /* a head request */
 318                 req->wb_head = req;
 319                 req->wb_this_page = req;
 320         } else {
 321                 /* a subrequest */
 322                 WARN_ON_ONCE(prev->wb_this_page != prev->wb_head);
 323                 WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &prev->wb_head->wb_flags));
 324                 req->wb_head = prev->wb_head;
 325                 req->wb_this_page = prev->wb_this_page;
 326                 prev->wb_this_page = req;
 327
 328                 /* All subrequests take a ref on the head request until
 329                  * nfs_page_group_destroy is called */
 330                 kref_get(&req->wb_head->wb_kref);
 331
 332                 /* grab extra ref and bump the request count if head request
 333                  * has extra ref from the write/commit path to handle handoff
 334                  * between write and commit lists. */
 335                 if (test_bit(PG_INODE_REF, &prev->wb_head->wb_flags)) {
 336                         inode = nfs_page_to_inode(req);
 337                         set_bit(PG_INODE_REF, &req->wb_flags);
 338                         kref_get(&req->wb_kref);
 339                         atomic_long_inc(&NFS_I(inode)->nrequests);
 340                 }
 341         }
 342 }
 343
 344 /*
 345  * nfs_page_group_destroy - sync the destruction of page groups
 346  * @req - request that no longer needs the page group
 347  *
 348  * releases the page group reference from each member once all
 349  * members have called this function.
 350  */
 351 static void
 352 nfs_page_group_destroy(struct kref *kref)
 353 {
 354         struct nfs_page *req = container_of(kref, struct nfs_page, wb_kref);
 355         struct nfs_page *head = req->wb_head;
 356         struct nfs_page *tmp, *next;
 357
 358         if (!nfs_page_group_sync_on_bit(req, PG_TEARDOWN))
 359                 goto out;
 360
 361         tmp = req;
 362         do {
 363                 next = tmp->wb_this_page;
 364                 /* unlink and free */
 365                 tmp->wb_this_page = tmp;
 366                 tmp->wb_head = tmp;
 367                 nfs_free_request(tmp);
 368                 tmp = next;
 369         } while (tmp != req);
 370 out:
 371         /* subrequests must release the ref on the head request */
 372         if (head != req)
 373                 nfs_release_request(head);
 374 }
 375
 376 static struct nfs_page *nfs_page_create(struct nfs_lock_context *l_ctx,
 377                                         unsigned int pgbase, pgoff_t index,
 378                                         unsigned int offset, unsigned int count)
 379 {
 380         struct nfs_page         *req;
 381         struct nfs_open_context *ctx = l_ctx->open_context;
 382
 383         if (test_bit(NFS_CONTEXT_BAD, &ctx->flags))
 384                 return ERR_PTR(-EBADF);
 385         /* try to allocate the request struct */
 386         req = nfs_page_alloc();
 387         if (req == NULL)
 388                 return ERR_PTR(-ENOMEM);
 389
 390         req->wb_lock_context = l_ctx;
 391         refcount_inc(&l_ctx->count);
 392         atomic_inc(&l_ctx->io_count);
 393
 394         /* Initialize the request struct. Initially, we assume a
 395          * long write-back delay. This will be adjusted in
 396          * update_nfs_request below if the region is not locked. */
 397         req->wb_pgbase = pgbase;
 398         req->wb_index = index;
 399         req->wb_offset = offset;
 400         req->wb_bytes = count;
 401         kref_init(&req->wb_kref);
 402         req->wb_nio = 0;
 403         return req;
 404 }
 405
 406 static void nfs_page_assign_folio(struct nfs_page *req, struct folio *folio)
 407 {
 408         if (folio != NULL) {
 409                 req->wb_folio = folio;
 410                 folio_get(folio);
 411                 set_bit(PG_FOLIO, &req->wb_flags);
 412         }
 413 }
 414
 415 static void nfs_page_assign_page(struct nfs_page *req, struct page *page)
 416 {
 417         if (page != NULL) {
 418                 req->wb_page = page;
 419                 get_page(page);
 420         }
 421 }
 422
 423 /**
 424  * nfs_page_create_from_page - Create an NFS read/write request.
 425  * @ctx: open context to use
 426  * @page: page to write
 427  * @pgbase: starting offset within the page for the write
 428  * @offset: file offset for the write
 429  * @count: number of bytes to read/write
 430  *
 431  * The page must be locked by the caller. This makes sure we never
 432  * create two different requests for the same page.
 433  * User should ensure it is safe to sleep in this function.
 434  */
 435 struct nfs_page *nfs_page_create_from_page(struct nfs_open_context *ctx,
 436                                            struct page *page,
 437                                            unsigned int pgbase, loff_t offset,
 438                                            unsigned int count)
 439 {
 440         struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx);
 441         struct nfs_page *ret;
 442
 443         if (IS_ERR(l_ctx))
 444                 return ERR_CAST(l_ctx);
 445         ret = nfs_page_create(l_ctx, pgbase, offset >> PAGE_SHIFT,
 446                               offset_in_page(offset), count);
 447         if (!IS_ERR(ret)) {
 448                 nfs_page_assign_page(ret, page);
 449                 nfs_page_group_init(ret, NULL);
 450         }
 451         nfs_put_lock_context(l_ctx);
 452         return ret;
 453 }
 454
 455 /**
 456  * nfs_page_create_from_folio - Create an NFS read/write request.
 457  * @ctx: open context to use
 458  * @folio: folio to write
 459  * @offset: starting offset within the folio for the write
 460  * @count: number of bytes to read/write
 461  *
 462  * The page must be locked by the caller. This makes sure we never
 463  * create two different requests for the same page.
 464  * User should ensure it is safe to sleep in this function.
 465  */
 466 struct nfs_page *nfs_page_create_from_folio(struct nfs_open_context *ctx,
 467                                             struct folio *folio,
 468                                             unsigned int offset,
 469                                             unsigned int count)
 470 {
 471         struct nfs_lock_context *l_ctx = nfs_get_lock_context(ctx);
 472         struct nfs_page *ret;
 473
 474         if (IS_ERR(l_ctx))
 475                 return ERR_CAST(l_ctx);
 476         ret = nfs_page_create(l_ctx, offset, folio->index, offset, count);
 477         if (!IS_ERR(ret)) {
 478                 nfs_page_assign_folio(ret, folio);
 479                 nfs_page_group_init(ret, NULL);
 480         }
 481         nfs_put_lock_context(l_ctx);
 482         return ret;
 483 }
 484
 485 static struct nfs_page *
 486 nfs_create_subreq(struct nfs_page *req,
 487                   unsigned int pgbase,
 488                   unsigned int offset,
 489                   unsigned int count)
 490 {
 491         struct nfs_page *last;
 492         struct nfs_page *ret;
 493         struct folio *folio = nfs_page_to_folio(req);
 494         struct page *page = nfs_page_to_page(req, pgbase);
 495
 496         ret = nfs_page_create(req->wb_lock_context, pgbase, req->wb_index,
 497                               offset, count);
 498         if (!IS_ERR(ret)) {
 499                 if (folio)
 500                         nfs_page_assign_folio(ret, folio);
 501                 else
 502                         nfs_page_assign_page(ret, page);
 503                 /* find the last request */
 504                 for (last = req->wb_head;
 505                      last->wb_this_page != req->wb_head;
 506                      last = last->wb_this_page)
 507                         ;
 508
 509                 nfs_lock_request(ret);
 510                 nfs_page_group_init(ret, last);
 511                 ret->wb_nio = req->wb_nio;
 512         }
 513         return ret;
 514 }
 515
 516 /**
 517  * nfs_unlock_request - Unlock request and wake up sleepers.
 518  * @req: pointer to request
 519  */
 520 void nfs_unlock_request(struct nfs_page *req)
 521 {
 522         clear_bit_unlock(PG_BUSY, &req->wb_flags);
 523         smp_mb__after_atomic();
 524         if (!test_bit(PG_CONTENDED2, &req->wb_flags))
 525                 return;
 526         wake_up_bit(&req->wb_flags, PG_BUSY);
 527 }
 528
 529 /**
 530  * nfs_unlock_and_release_request - Unlock request and release the nfs_page
 531  * @req: pointer to request
 532  */
 533 void nfs_unlock_and_release_request(struct nfs_page *req)
 534 {
 535         nfs_unlock_request(req);
 536         nfs_release_request(req);
 537 }
 538
 539 /*
 540  * nfs_clear_request - Free up all resources allocated to the request
 541  * @req:
 542  *
 543  * Release page and open context resources associated with a read/write
 544  * request after it has completed.
 545  */
 546 static void nfs_clear_request(struct nfs_page *req)
 547 {
 548         struct folio *folio = nfs_page_to_folio(req);
 549         struct page *page = req->wb_page;
 550         struct nfs_lock_context *l_ctx = req->wb_lock_context;
 551         struct nfs_open_context *ctx;
 552
 553         if (folio != NULL) {
 554                 folio_put(folio);
 555                 req->wb_folio = NULL;
 556                 clear_bit(PG_FOLIO, &req->wb_flags);
 557         } else if (page != NULL) {
 558                 put_page(page);
 559                 req->wb_page = NULL;
 560         }
 561         if (l_ctx != NULL) {
 562                 if (atomic_dec_and_test(&l_ctx->io_count)) {
 563                         wake_up_var(&l_ctx->io_count);
 564                         ctx = l_ctx->open_context;
 565                         if (test_bit(NFS_CONTEXT_UNLOCK, &ctx->flags))
 566                                 rpc_wake_up(&NFS_SERVER(d_inode(ctx->dentry))->uoc_rpcwaitq);
 567                 }
 568                 nfs_put_lock_context(l_ctx);
 569                 req->wb_lock_context = NULL;
 570         }
 571 }
 572
 573 /**
 574  * nfs_free_request - Release the count on an NFS read/write request
 575  * @req: request to release
 576  *
 577  * Note: Should never be called with the spinlock held!
 578  */
 579 void nfs_free_request(struct nfs_page *req)
 580 {
 581         WARN_ON_ONCE(req->wb_this_page != req);
 582
 583         /* extra debug: make sure no sync bits are still set */
 584         WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags));
 585         WARN_ON_ONCE(test_bit(PG_UNLOCKPAGE, &req->wb_flags));
 586         WARN_ON_ONCE(test_bit(PG_UPTODATE, &req->wb_flags));
 587         WARN_ON_ONCE(test_bit(PG_WB_END, &req->wb_flags));
 588         WARN_ON_ONCE(test_bit(PG_REMOVE, &req->wb_flags));
 589
 590         /* Release struct file and open context */
 591         nfs_clear_request(req);
 592         nfs_page_free(req);
 593 }
 594
 595 void nfs_release_request(struct nfs_page *req)
 596 {
 597         kref_put(&req->wb_kref, nfs_page_group_destroy);
 598 }
 599 EXPORT_SYMBOL_GPL(nfs_release_request);
 600
 601 /*
 602  * nfs_generic_pg_test - determine if requests can be coalesced
 603  * @desc: pointer to descriptor
 604  * @prev: previous request in desc, or NULL
 605  * @req: this request
 606  *
 607  * Returns zero if @req cannot be coalesced into @desc, otherwise it returns
 608  * the size of the request.
 609  */
 610 size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc,
 611                            struct nfs_page *prev, struct nfs_page *req)
 612 {
 613         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 614
 615
 616         if (mirror->pg_count > mirror->pg_bsize) {
 617                 /* should never happen */
 618                 WARN_ON_ONCE(1);
 619                 return 0;
 620         }
 621
 622         /*
 623          * Limit the request size so that we can still allocate a page array
 624          * for it without upsetting the slab allocator.
 625          */
 626         if (((mirror->pg_count + req->wb_bytes) >> PAGE_SHIFT) *
 627                         sizeof(struct page *) > PAGE_SIZE)
 628                 return 0;
 629
 630         return min(mirror->pg_bsize - mirror->pg_count, (size_t)req->wb_bytes);
 631 }
 632 EXPORT_SYMBOL_GPL(nfs_generic_pg_test);
 633
 634 struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *ops)
 635 {
 636         struct nfs_pgio_header *hdr = ops->rw_alloc_header();
 637
 638         if (hdr) {
 639                 INIT_LIST_HEAD(&hdr->pages);
 640                 hdr->rw_ops = ops;
 641         }
 642         return hdr;
 643 }
 644 EXPORT_SYMBOL_GPL(nfs_pgio_header_alloc);
 645
 646 /**
 647  * nfs_pgio_data_destroy - make @hdr suitable for reuse
 648  *
 649  * Frees memory and releases refs from nfs_generic_pgio, so that it may
 650  * be called again.
 651  *
 652  * @hdr: A header that has had nfs_generic_pgio called
 653  */
 654 static void nfs_pgio_data_destroy(struct nfs_pgio_header *hdr)
 655 {
 656         if (hdr->args.context)
 657                 put_nfs_open_context(hdr->args.context);
 658         if (hdr->page_array.pagevec != hdr->page_array.page_array)
 659                 kfree(hdr->page_array.pagevec);
 660 }
 661
 662 /*
 663  * nfs_pgio_header_free - Free a read or write header
 664  * @hdr: The header to free
 665  */
 666 void nfs_pgio_header_free(struct nfs_pgio_header *hdr)
 667 {
 668         nfs_pgio_data_destroy(hdr);
 669         hdr->rw_ops->rw_free_header(hdr);
 670 }
 671 EXPORT_SYMBOL_GPL(nfs_pgio_header_free);
 672
 673 /**
 674  * nfs_pgio_rpcsetup - Set up arguments for a pageio call
 675  * @hdr: The pageio hdr
 676  * @pgbase: base
 677  * @count: Number of bytes to read
 678  * @how: How to commit data (writes only)
 679  * @cinfo: Commit information for the call (writes only)
 680  */
 681 static void nfs_pgio_rpcsetup(struct nfs_pgio_header *hdr, unsigned int pgbase,
 682                               unsigned int count, int how,
 683                               struct nfs_commit_info *cinfo)
 684 {
 685         struct nfs_page *req = hdr->req;
 686
 687         /* Set up the RPC argument and reply structs
 688          * NB: take care not to mess about with hdr->commit et al. */
 689
 690         hdr->args.fh     = NFS_FH(hdr->inode);
 691         hdr->args.offset = req_offset(req);
 692         /* pnfs_set_layoutcommit needs this */
 693         hdr->mds_offset = hdr->args.offset;
 694         hdr->args.pgbase = pgbase;
 695         hdr->args.pages  = hdr->page_array.pagevec;
 696         hdr->args.count  = count;
 697         hdr->args.context = get_nfs_open_context(nfs_req_openctx(req));
 698         hdr->args.lock_context = req->wb_lock_context;
 699         hdr->args.stable  = NFS_UNSTABLE;
 700         switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
 701         case 0:
 702                 break;
 703         case FLUSH_COND_STABLE:
 704                 if (nfs_reqs_to_commit(cinfo))
 705                         break;
 706                 fallthrough;
 707         default:
 708                 hdr->args.stable = NFS_FILE_SYNC;
 709         }
 710
 711         hdr->res.fattr   = &hdr->fattr;
 712         hdr->res.count   = 0;
 713         hdr->res.eof     = 0;
 714         hdr->res.verf    = &hdr->verf;
 715         nfs_fattr_init(&hdr->fattr);
 716 }
 717
 718 /**
 719  * nfs_pgio_prepare - Prepare pageio hdr to go over the wire
 720  * @task: The current task
 721  * @calldata: pageio header to prepare
 722  */
 723 static void nfs_pgio_prepare(struct rpc_task *task, void *calldata)
 724 {
 725         struct nfs_pgio_header *hdr = calldata;
 726         int err;
 727         err = NFS_PROTO(hdr->inode)->pgio_rpc_prepare(task, hdr);
 728         if (err)
 729                 rpc_exit(task, err);
 730 }
 731
 732 int nfs_initiate_pgio(struct rpc_clnt *clnt, struct nfs_pgio_header *hdr,
 733                       const struct cred *cred, const struct nfs_rpc_ops *rpc_ops,
 734                       const struct rpc_call_ops *call_ops, int how, int flags,
 735                       struct nfsd_file *localio)
 736 {
 737         struct rpc_task *task;
 738         struct rpc_message msg = {
 739                 .rpc_argp = &hdr->args,
 740                 .rpc_resp = &hdr->res,
 741                 .rpc_cred = cred,
 742         };
 743         struct rpc_task_setup task_setup_data = {
 744                 .rpc_client = clnt,
 745                 .task = &hdr->task,
 746                 .rpc_message = &msg,
 747                 .callback_ops = call_ops,
 748                 .callback_data = hdr,
 749                 .workqueue = nfsiod_workqueue,
 750                 .flags = RPC_TASK_ASYNC | flags,
 751         };
 752
 753         if (nfs_server_capable(hdr->inode, NFS_CAP_MOVEABLE))
 754                 task_setup_data.flags |= RPC_TASK_MOVEABLE;
 755
 756         hdr->rw_ops->rw_initiate(hdr, &msg, rpc_ops, &task_setup_data, how);
 757
 758         dprintk("NFS: initiated pgio call "
 759                 "(req %s/%llu, %u bytes @ offset %llu)\n",
 760                 hdr->inode->i_sb->s_id,
 761                 (unsigned long long)NFS_FILEID(hdr->inode),
 762                 hdr->args.count,
 763                 (unsigned long long)hdr->args.offset);
 764
 765         if (localio)
 766                 return nfs_local_doio(NFS_SERVER(hdr->inode)->nfs_client,
 767                                       localio, hdr, call_ops);
 768
 769         task = rpc_run_task(&task_setup_data);
 770         if (IS_ERR(task))
 771                 return PTR_ERR(task);
 772         rpc_put_task(task);
 773         return 0;
 774 }
 775 EXPORT_SYMBOL_GPL(nfs_initiate_pgio);
 776
 777 /**
 778  * nfs_pgio_error - Clean up from a pageio error
 779  * @hdr: pageio header
 780  */
 781 static void nfs_pgio_error(struct nfs_pgio_header *hdr)
 782 {
 783         set_bit(NFS_IOHDR_REDO, &hdr->flags);
 784         hdr->completion_ops->completion(hdr);
 785 }
 786
 787 /**
 788  * nfs_pgio_release - Release pageio data
 789  * @calldata: The pageio header to release
 790  */
 791 static void nfs_pgio_release(void *calldata)
 792 {
 793         struct nfs_pgio_header *hdr = calldata;
 794         hdr->completion_ops->completion(hdr);
 795 }
 796
 797 static void nfs_pageio_mirror_init(struct nfs_pgio_mirror *mirror,
 798                                    unsigned int bsize)
 799 {
 800         INIT_LIST_HEAD(&mirror->pg_list);
 801         mirror->pg_bytes_written = 0;
 802         mirror->pg_count = 0;
 803         mirror->pg_bsize = bsize;
 804         mirror->pg_base = 0;
 805         mirror->pg_recoalesce = 0;
 806 }
 807
 808 /**
 809  * nfs_pageio_init - initialise a page io descriptor
 810  * @desc: pointer to descriptor
 811  * @inode: pointer to inode
 812  * @pg_ops: pointer to pageio operations
 813  * @compl_ops: pointer to pageio completion operations
 814  * @rw_ops: pointer to nfs read/write operations
 815  * @bsize: io block size
 816  * @io_flags: extra parameters for the io function
 817  */
 818 void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
 819                      struct inode *inode,
 820                      const struct nfs_pageio_ops *pg_ops,
 821                      const struct nfs_pgio_completion_ops *compl_ops,
 822                      const struct nfs_rw_ops *rw_ops,
 823                      size_t bsize,
 824                      int io_flags)
 825 {
 826         desc->pg_moreio = 0;
 827         desc->pg_inode = inode;
 828         desc->pg_ops = pg_ops;
 829         desc->pg_completion_ops = compl_ops;
 830         desc->pg_rw_ops = rw_ops;
 831         desc->pg_ioflags = io_flags;
 832         desc->pg_error = 0;
 833         desc->pg_lseg = NULL;
 834         desc->pg_io_completion = NULL;
 835         desc->pg_dreq = NULL;
 836         nfs_netfs_reset_pageio_descriptor(desc);
 837         desc->pg_bsize = bsize;
 838
 839         desc->pg_mirror_count = 1;
 840         desc->pg_mirror_idx = 0;
 841
 842         desc->pg_mirrors_dynamic = NULL;
 843         desc->pg_mirrors = desc->pg_mirrors_static;
 844         nfs_pageio_mirror_init(&desc->pg_mirrors[0], bsize);
 845         desc->pg_maxretrans = 0;
 846 }
 847
 848 /**
 849  * nfs_pgio_result - Basic pageio error handling
 850  * @task: The task that ran
 851  * @calldata: Pageio header to check
 852  */
 853 static void nfs_pgio_result(struct rpc_task *task, void *calldata)
 854 {
 855         struct nfs_pgio_header *hdr = calldata;
 856         struct inode *inode = hdr->inode;
 857
 858         if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
 859                 return;
 860         if (task->tk_status < 0)
 861                 nfs_set_pgio_error(hdr, task->tk_status, hdr->args.offset);
 862         else
 863                 hdr->rw_ops->rw_result(task, hdr);
 864 }
 865
 866 /*
 867  * Create an RPC task for the given read or write request and kick it.
 868  * The page must have been locked by the caller.
 869  *
 870  * It may happen that the page we're passed is not marked dirty.
 871  * This is the case if nfs_updatepage detects a conflicting request
 872  * that has been written but not committed.
 873  */
 874 int nfs_generic_pgio(struct nfs_pageio_descriptor *desc,
 875                      struct nfs_pgio_header *hdr)
 876 {
 877         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
 878
 879         struct nfs_page         *req;
 880         struct page             **pages,
 881                                 *last_page;
 882         struct list_head *head = &mirror->pg_list;
 883         struct nfs_commit_info cinfo;
 884         struct nfs_page_array *pg_array = &hdr->page_array;
 885         unsigned int pagecount, pageused;
 886         unsigned int pg_base = offset_in_page(mirror->pg_base);
 887         gfp_t gfp_flags = nfs_io_gfp_mask();
 888
 889         pagecount = nfs_page_array_len(pg_base, mirror->pg_count);
 890         pg_array->npages = pagecount;
 891
 892         if (pagecount <= ARRAY_SIZE(pg_array->page_array))
 893                 pg_array->pagevec = pg_array->page_array;
 894         else {
 895                 pg_array->pagevec = kcalloc(pagecount, sizeof(struct page *), gfp_flags);
 896                 if (!pg_array->pagevec) {
 897                         pg_array->npages = 0;
 898                         nfs_pgio_error(hdr);
 899                         desc->pg_error = -ENOMEM;
 900                         return desc->pg_error;
 901                 }
 902         }
 903
 904         nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
 905         pages = hdr->page_array.pagevec;
 906         last_page = NULL;
 907         pageused = 0;
 908         while (!list_empty(head)) {
 909                 struct nfs_page_iter_page i;
 910                 struct page *page;
 911
 912                 req = nfs_list_entry(head->next);
 913                 nfs_list_move_request(req, &hdr->pages);
 914
 915                 if (req->wb_pgbase == 0)
 916                         last_page = NULL;
 917
 918                 nfs_page_iter_page_init(&i, req);
 919                 while ((page = nfs_page_iter_page_get(&i)) != NULL) {
 920                         if (last_page != page) {
 921                                 pageused++;
 922                                 if (pageused > pagecount)
 923                                         goto full;
 924                                 *pages++ = last_page = page;
 925                         }
 926                 }
 927         }
 928 full:
 929         if (WARN_ON_ONCE(pageused != pagecount)) {
 930                 nfs_pgio_error(hdr);
 931                 desc->pg_error = -EINVAL;
 932                 return desc->pg_error;
 933         }
 934
 935         if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
 936             (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
 937                 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
 938
 939         /* Set up the argument struct */
 940         nfs_pgio_rpcsetup(hdr, pg_base, mirror->pg_count, desc->pg_ioflags,
 941                           &cinfo);
 942         desc->pg_rpc_callops = &nfs_pgio_common_ops;
 943         return 0;
 944 }
 945 EXPORT_SYMBOL_GPL(nfs_generic_pgio);
 946
 947 static int nfs_generic_pg_pgios(struct nfs_pageio_descriptor *desc)
 948 {
 949         struct nfs_pgio_header *hdr;
 950         int ret;
 951         unsigned short task_flags = 0;
 952
 953         hdr = nfs_pgio_header_alloc(desc->pg_rw_ops);
 954         if (!hdr) {
 955                 desc->pg_error = -ENOMEM;
 956                 return desc->pg_error;
 957         }
 958         nfs_pgheader_init(desc, hdr, nfs_pgio_header_free);
 959         ret = nfs_generic_pgio(desc, hdr);
 960         if (ret == 0) {
 961                 struct nfs_client *clp = NFS_SERVER(hdr->inode)->nfs_client;
 962
 963                 struct nfsd_file *localio =
 964                         nfs_local_open_fh(clp, hdr->cred,
 965                                           hdr->args.fh, hdr->args.context->mode);
 966
 967                 if (NFS_SERVER(hdr->inode)->nfs_client->cl_minorversion)
 968                         task_flags = RPC_TASK_MOVEABLE;
 969                 ret = nfs_initiate_pgio(NFS_CLIENT(hdr->inode),
 970                                         hdr,
 971                                         hdr->cred,
 972                                         NFS_PROTO(hdr->inode),
 973                                         desc->pg_rpc_callops,
 974                                         desc->pg_ioflags,
 975                                         RPC_TASK_CRED_NOREF | task_flags,
 976                                         localio);
 977         }
 978         return ret;
 979 }
 980
 981 static struct nfs_pgio_mirror *
 982 nfs_pageio_alloc_mirrors(struct nfs_pageio_descriptor *desc,
 983                 unsigned int mirror_count)
 984 {
 985         struct nfs_pgio_mirror *ret;
 986         unsigned int i;
 987
 988         kfree(desc->pg_mirrors_dynamic);
 989         desc->pg_mirrors_dynamic = NULL;
 990         if (mirror_count == 1)
 991                 return desc->pg_mirrors_static;
 992         ret = kmalloc_array(mirror_count, sizeof(*ret), nfs_io_gfp_mask());
 993         if (ret != NULL) {
 994                 for (i = 0; i < mirror_count; i++)
 995                         nfs_pageio_mirror_init(&ret[i], desc->pg_bsize);
 996                 desc->pg_mirrors_dynamic = ret;
 997         }
 998         return ret;
 999 }
1000
1001 /*
1002  * nfs_pageio_setup_mirroring - determine if mirroring is to be used
1003  *                              by calling the pg_get_mirror_count op
1004  */
1005 static void nfs_pageio_setup_mirroring(struct nfs_pageio_descriptor *pgio,
1006                                        struct nfs_page *req)
1007 {
1008         unsigned int mirror_count = 1;
1009
1010         if (pgio->pg_ops->pg_get_mirror_count)
1011                 mirror_count = pgio->pg_ops->pg_get_mirror_count(pgio, req);
1012         if (mirror_count == pgio->pg_mirror_count || pgio->pg_error < 0)
1013                 return;
1014
1015         if (!mirror_count || mirror_count > NFS_PAGEIO_DESCRIPTOR_MIRROR_MAX) {
1016                 pgio->pg_error = -EINVAL;
1017                 return;
1018         }
1019
1020         pgio->pg_mirrors = nfs_pageio_alloc_mirrors(pgio, mirror_count);
1021         if (pgio->pg_mirrors == NULL) {
1022                 pgio->pg_error = -ENOMEM;
1023                 pgio->pg_mirrors = pgio->pg_mirrors_static;
1024                 mirror_count = 1;
1025         }
1026         pgio->pg_mirror_count = mirror_count;
1027 }
1028
1029 static void nfs_pageio_cleanup_mirroring(struct nfs_pageio_descriptor *pgio)
1030 {
1031         pgio->pg_mirror_count = 1;
1032         pgio->pg_mirror_idx = 0;
1033         pgio->pg_mirrors = pgio->pg_mirrors_static;
1034         kfree(pgio->pg_mirrors_dynamic);
1035         pgio->pg_mirrors_dynamic = NULL;
1036 }
1037
1038 static bool nfs_match_lock_context(const struct nfs_lock_context *l1,
1039                 const struct nfs_lock_context *l2)
1040 {
1041         return l1->lockowner == l2->lockowner;
1042 }
1043
1044 static bool nfs_page_is_contiguous(const struct nfs_page *prev,
1045                                    const struct nfs_page *req)
1046 {
1047         size_t prev_end = prev->wb_pgbase + prev->wb_bytes;
1048
1049         if (req_offset(req) != req_offset(prev) + prev->wb_bytes)
1050                 return false;
1051         if (req->wb_pgbase == 0)
1052                 return prev_end == nfs_page_max_length(prev);
1053         if (req->wb_pgbase == prev_end) {
1054                 struct folio *folio = nfs_page_to_folio(req);
1055                 if (folio)
1056                         return folio == nfs_page_to_folio(prev);
1057                 return req->wb_page == prev->wb_page;
1058         }
1059         return false;
1060 }
1061
1062 /**
1063  * nfs_coalesce_size - test two requests for compatibility
1064  * @prev: pointer to nfs_page
1065  * @req: pointer to nfs_page
1066  * @pgio: pointer to nfs_pagio_descriptor
1067  *
1068  * The nfs_page structures 'prev' and 'req' are compared to ensure that the
1069  * page data area they describe is contiguous, and that their RPC
1070  * credentials, NFSv4 open state, and lockowners are the same.
1071  *
1072  * Returns size of the request that can be coalesced
1073  */
1074 static unsigned int nfs_coalesce_size(struct nfs_page *prev,
1075                                       struct nfs_page *req,
1076                                       struct nfs_pageio_descriptor *pgio)
1077 {
1078         struct file_lock_context *flctx;
1079
1080         if (prev) {
1081                 if (!nfs_match_open_context(nfs_req_openctx(req), nfs_req_openctx(prev)))
1082                         return 0;
1083                 flctx = locks_inode_context(d_inode(nfs_req_openctx(req)->dentry));
1084                 if (flctx != NULL &&
1085                     !(list_empty_careful(&flctx->flc_posix) &&
1086                       list_empty_careful(&flctx->flc_flock)) &&
1087                     !nfs_match_lock_context(req->wb_lock_context,
1088                                             prev->wb_lock_context))
1089                         return 0;
1090                 if (!nfs_page_is_contiguous(prev, req))
1091                         return 0;
1092         }
1093         return pgio->pg_ops->pg_test(pgio, prev, req);
1094 }
1095
1096 /**
1097  * nfs_pageio_do_add_request - Attempt to coalesce a request into a page list.
1098  * @desc: destination io descriptor
1099  * @req: request
1100  *
1101  * If the request 'req' was successfully coalesced into the existing list
1102  * of pages 'desc', it returns the size of req.
1103  */
1104 static unsigned int
1105 nfs_pageio_do_add_request(struct nfs_pageio_descriptor *desc,
1106                 struct nfs_page *req)
1107 {
1108         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1109         struct nfs_page *prev = NULL;
1110         unsigned int size;
1111
1112         if (list_empty(&mirror->pg_list)) {
1113                 if (desc->pg_ops->pg_init)
1114                         desc->pg_ops->pg_init(desc, req);
1115                 if (desc->pg_error < 0)
1116                         return 0;
1117                 mirror->pg_base = req->wb_pgbase;
1118                 mirror->pg_count = 0;
1119                 mirror->pg_recoalesce = 0;
1120         } else
1121                 prev = nfs_list_entry(mirror->pg_list.prev);
1122
1123         if (desc->pg_maxretrans && req->wb_nio > desc->pg_maxretrans) {
1124                 if (NFS_SERVER(desc->pg_inode)->flags & NFS_MOUNT_SOFTERR)
1125                         desc->pg_error = -ETIMEDOUT;
1126                 else
1127                         desc->pg_error = -EIO;
1128                 return 0;
1129         }
1130
1131         size = nfs_coalesce_size(prev, req, desc);
1132         if (size < req->wb_bytes)
1133                 return size;
1134         nfs_list_move_request(req, &mirror->pg_list);
1135         mirror->pg_count += req->wb_bytes;
1136         return req->wb_bytes;
1137 }
1138
1139 /*
1140  * Helper for nfs_pageio_add_request and nfs_pageio_complete
1141  */
1142 static void nfs_pageio_doio(struct nfs_pageio_descriptor *desc)
1143 {
1144         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1145
1146         if (!list_empty(&mirror->pg_list)) {
1147                 int error = desc->pg_ops->pg_doio(desc);
1148                 if (error < 0)
1149                         desc->pg_error = error;
1150                 if (list_empty(&mirror->pg_list))
1151                         mirror->pg_bytes_written += mirror->pg_count;
1152         }
1153 }
1154
1155 static void
1156 nfs_pageio_cleanup_request(struct nfs_pageio_descriptor *desc,
1157                 struct nfs_page *req)
1158 {
1159         LIST_HEAD(head);
1160
1161         nfs_list_move_request(req, &head);
1162         desc->pg_completion_ops->error_cleanup(&head, desc->pg_error);
1163 }
1164
1165 /**
1166  * __nfs_pageio_add_request - Attempt to coalesce a request into a page list.
1167  * @desc: destination io descriptor
1168  * @req: request
1169  *
1170  * This may split a request into subrequests which are all part of the
1171  * same page group. If so, it will submit @req as the last one, to ensure
1172  * the pointer to @req is still valid in case of failure.
1173  *
1174  * Returns true if the request 'req' was successfully coalesced into the
1175  * existing list of pages 'desc'.
1176  */
1177 static int __nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1178                            struct nfs_page *req)
1179 {
1180         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1181         struct nfs_page *subreq;
1182         unsigned int size, subreq_size;
1183
1184         nfs_page_group_lock(req);
1185
1186         subreq = req;
1187         subreq_size = subreq->wb_bytes;
1188         for(;;) {
1189                 size = nfs_pageio_do_add_request(desc, subreq);
1190                 if (size == subreq_size) {
1191                         /* We successfully submitted a request */
1192                         if (subreq == req)
1193                                 break;
1194                         req->wb_pgbase += size;
1195                         req->wb_bytes -= size;
1196                         req->wb_offset += size;
1197                         subreq_size = req->wb_bytes;
1198                         subreq = req;
1199                         continue;
1200                 }
1201                 if (WARN_ON_ONCE(subreq != req)) {
1202                         nfs_page_group_unlock(req);
1203                         nfs_pageio_cleanup_request(desc, subreq);
1204                         subreq = req;
1205                         subreq_size = req->wb_bytes;
1206                         nfs_page_group_lock(req);
1207                 }
1208                 if (!size) {
1209                         /* Can't coalesce any more, so do I/O */
1210                         nfs_page_group_unlock(req);
1211                         desc->pg_moreio = 1;
1212                         nfs_pageio_doio(desc);
1213                         if (desc->pg_error < 0 || mirror->pg_recoalesce)
1214                                 return 0;
1215                         /* retry add_request for this subreq */
1216                         nfs_page_group_lock(req);
1217                         continue;
1218                 }
1219                 subreq = nfs_create_subreq(req, req->wb_pgbase,
1220                                 req->wb_offset, size);
1221                 if (IS_ERR(subreq))
1222                         goto err_ptr;
1223                 subreq_size = size;
1224         }
1225
1226         nfs_page_group_unlock(req);
1227         return 1;
1228 err_ptr:
1229         desc->pg_error = PTR_ERR(subreq);
1230         nfs_page_group_unlock(req);
1231         return 0;
1232 }
1233
1234 static int nfs_do_recoalesce(struct nfs_pageio_descriptor *desc)
1235 {
1236         struct nfs_pgio_mirror *mirror = nfs_pgio_current_mirror(desc);
1237         LIST_HEAD(head);
1238
1239         do {
1240                 list_splice_init(&mirror->pg_list, &head);
1241                 mirror->pg_recoalesce = 0;
1242
1243                 while (!list_empty(&head)) {
1244                         struct nfs_page *req;
1245
1246                         req = list_first_entry(&head, struct nfs_page, wb_list);
1247                         if (__nfs_pageio_add_request(desc, req))
1248                                 continue;
1249                         if (desc->pg_error < 0) {
1250                                 list_splice_tail(&head, &mirror->pg_list);
1251                                 mirror->pg_recoalesce = 1;
1252                                 return 0;
1253                         }
1254                         break;
1255                 }
1256         } while (mirror->pg_recoalesce);
1257         return 1;
1258 }
1259
1260 static int nfs_pageio_add_request_mirror(struct nfs_pageio_descriptor *desc,
1261                 struct nfs_page *req)
1262 {
1263         int ret;
1264
1265         do {
1266                 ret = __nfs_pageio_add_request(desc, req);
1267                 if (ret)
1268                         break;
1269                 if (desc->pg_error < 0)
1270                         break;
1271                 ret = nfs_do_recoalesce(desc);
1272         } while (ret);
1273
1274         return ret;
1275 }
1276
1277 static void nfs_pageio_error_cleanup(struct nfs_pageio_descriptor *desc)
1278 {
1279         u32 midx;
1280         struct nfs_pgio_mirror *mirror;
1281
1282         if (!desc->pg_error)
1283                 return;
1284
1285         for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1286                 mirror = nfs_pgio_get_mirror(desc, midx);
1287                 desc->pg_completion_ops->error_cleanup(&mirror->pg_list,
1288                                 desc->pg_error);
1289         }
1290 }
1291
1292 int nfs_pageio_add_request(struct nfs_pageio_descriptor *desc,
1293                            struct nfs_page *req)
1294 {
1295         u32 midx;
1296         unsigned int pgbase, offset, bytes;
1297         struct nfs_page *dupreq;
1298
1299         pgbase = req->wb_pgbase;
1300         offset = req->wb_offset;
1301         bytes = req->wb_bytes;
1302
1303         nfs_pageio_setup_mirroring(desc, req);
1304         if (desc->pg_error < 0)
1305                 goto out_failed;
1306
1307         /* Create the mirror instances first, and fire them off */
1308         for (midx = 1; midx < desc->pg_mirror_count; midx++) {
1309                 nfs_page_group_lock(req);
1310
1311                 dupreq = nfs_create_subreq(req,
1312                                 pgbase, offset, bytes);
1313
1314                 nfs_page_group_unlock(req);
1315                 if (IS_ERR(dupreq)) {
1316                         desc->pg_error = PTR_ERR(dupreq);
1317                         goto out_failed;
1318                 }
1319
1320                 nfs_pgio_set_current_mirror(desc, midx);
1321                 if (!nfs_pageio_add_request_mirror(desc, dupreq))
1322                         goto out_cleanup_subreq;
1323         }
1324
1325         nfs_pgio_set_current_mirror(desc, 0);
1326         if (!nfs_pageio_add_request_mirror(desc, req))
1327                 goto out_failed;
1328
1329         return 1;
1330
1331 out_cleanup_subreq:
1332         nfs_pageio_cleanup_request(desc, dupreq);
1333 out_failed:
1334         nfs_pageio_error_cleanup(desc);
1335         return 0;
1336 }
1337
1338 /*
1339  * nfs_pageio_complete_mirror - Complete I/O on the current mirror of an
1340  *                              nfs_pageio_descriptor
1341  * @desc: pointer to io descriptor
1342  * @mirror_idx: pointer to mirror index
1343  */
1344 static void nfs_pageio_complete_mirror(struct nfs_pageio_descriptor *desc,
1345                                        u32 mirror_idx)
1346 {
1347         struct nfs_pgio_mirror *mirror;
1348         u32 restore_idx;
1349
1350         restore_idx = nfs_pgio_set_current_mirror(desc, mirror_idx);
1351         mirror = nfs_pgio_current_mirror(desc);
1352
1353         for (;;) {
1354                 nfs_pageio_doio(desc);
1355                 if (desc->pg_error < 0 || !mirror->pg_recoalesce)
1356                         break;
1357                 if (!nfs_do_recoalesce(desc))
1358                         break;
1359         }
1360         nfs_pgio_set_current_mirror(desc, restore_idx);
1361 }
1362
1363 /*
1364  * nfs_pageio_resend - Transfer requests to new descriptor and resend
1365  * @hdr - the pgio header to move request from
1366  * @desc - the pageio descriptor to add requests to
1367  *
1368  * Try to move each request (nfs_page) from @hdr to @desc then attempt
1369  * to send them.
1370  *
1371  * Returns 0 on success and < 0 on error.
1372  */
1373 int nfs_pageio_resend(struct nfs_pageio_descriptor *desc,
1374                       struct nfs_pgio_header *hdr)
1375 {
1376         LIST_HEAD(pages);
1377
1378         desc->pg_io_completion = hdr->io_completion;
1379         desc->pg_dreq = hdr->dreq;
1380         nfs_netfs_set_pageio_descriptor(desc, hdr);
1381         list_splice_init(&hdr->pages, &pages);
1382         while (!list_empty(&pages)) {
1383                 struct nfs_page *req = nfs_list_entry(pages.next);
1384
1385                 if (!nfs_pageio_add_request(desc, req))
1386                         break;
1387         }
1388         nfs_pageio_complete(desc);
1389         if (!list_empty(&pages)) {
1390                 int err = desc->pg_error < 0 ? desc->pg_error : -EIO;
1391                 hdr->completion_ops->error_cleanup(&pages, err);
1392                 nfs_set_pgio_error(hdr, err, hdr->io_start);
1393                 return err;
1394         }
1395         return 0;
1396 }
1397 EXPORT_SYMBOL_GPL(nfs_pageio_resend);
1398
1399 /**
1400  * nfs_pageio_complete - Complete I/O then cleanup an nfs_pageio_descriptor
1401  * @desc: pointer to io descriptor
1402  */
1403 void nfs_pageio_complete(struct nfs_pageio_descriptor *desc)
1404 {
1405         u32 midx;
1406
1407         for (midx = 0; midx < desc->pg_mirror_count; midx++)
1408                 nfs_pageio_complete_mirror(desc, midx);
1409
1410         if (desc->pg_error < 0)
1411                 nfs_pageio_error_cleanup(desc);
1412         if (desc->pg_ops->pg_cleanup)
1413                 desc->pg_ops->pg_cleanup(desc);
1414         nfs_pageio_cleanup_mirroring(desc);
1415 }
1416
1417 /**
1418  * nfs_pageio_cond_complete - Conditional I/O completion
1419  * @desc: pointer to io descriptor
1420  * @index: page index
1421  *
1422  * It is important to ensure that processes don't try to take locks
1423  * on non-contiguous ranges of pages as that might deadlock. This
1424  * function should be called before attempting to wait on a locked
1425  * nfs_page. It will complete the I/O if the page index 'index'
1426  * is not contiguous with the existing list of pages in 'desc'.
1427  */
1428 void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *desc, pgoff_t index)
1429 {
1430         struct nfs_pgio_mirror *mirror;
1431         struct nfs_page *prev;
1432         struct folio *folio;
1433         u32 midx;
1434
1435         for (midx = 0; midx < desc->pg_mirror_count; midx++) {
1436                 mirror = nfs_pgio_get_mirror(desc, midx);
1437                 if (!list_empty(&mirror->pg_list)) {
1438                         prev = nfs_list_entry(mirror->pg_list.prev);
1439                         folio = nfs_page_to_folio(prev);
1440                         if (folio) {
1441                                 if (index == folio_next_index(folio))
1442                                         continue;
1443                         } else if (index == prev->wb_index + 1)
1444                                 continue;
1445                         /*
1446                          * We will submit more requests after these. Indicate
1447                          * this to the underlying layers.
1448                          */
1449                         desc->pg_moreio = 1;
1450                         nfs_pageio_complete(desc);
1451                         break;
1452                 }
1453         }
1454 }
1455
1456 /*
1457  * nfs_pageio_stop_mirroring - stop using mirroring (set mirror count to 1)
1458  */
1459 void nfs_pageio_stop_mirroring(struct nfs_pageio_descriptor *pgio)
1460 {
1461         nfs_pageio_complete(pgio);
1462 }
1463
1464 int __init nfs_init_nfspagecache(void)
1465 {
1466         nfs_page_cachep = kmem_cache_create("nfs_page",
1467                                             sizeof(struct nfs_page),
1468                                             0, SLAB_HWCACHE_ALIGN,
1469                                             NULL);
1470         if (nfs_page_cachep == NULL)
1471                 return -ENOMEM;
1472
1473         return 0;
1474 }
1475
1476 void nfs_destroy_nfspagecache(void)
1477 {
1478         kmem_cache_destroy(nfs_page_cachep);
1479 }
1480
1481 static const struct rpc_call_ops nfs_pgio_common_ops = {
1482         .rpc_call_prepare = nfs_pgio_prepare,
1483         .rpc_call_done = nfs_pgio_result,
1484         .rpc_release = nfs_pgio_release,
1485 };
1486
1487 const struct nfs_pageio_ops nfs_pgio_rw_ops = {
1488         .pg_test = nfs_generic_pg_test,
1489         .pg_doio = nfs_generic_pg_pgios,
1490 };