fs/nfs/write.c

   1 /*
   2  * linux/fs/nfs/write.c
   3  *
   4  * Write file data over NFS.
   5  *
   6  * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/slab.h>
  11 #include <linux/mm.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/file.h>
  14 #include <linux/writeback.h>
  15 #include <linux/swap.h>
  16 #include <linux/migrate.h>
  17
  18 #include <linux/sunrpc/clnt.h>
  19 #include <linux/nfs_fs.h>
  20 #include <linux/nfs_mount.h>
  21 #include <linux/nfs_page.h>
  22 #include <linux/backing-dev.h>
  23 #include <linux/export.h>
  24
  25 #include <asm/uaccess.h>
  26
  27 #include "delegation.h"
  28 #include "internal.h"
  29 #include "iostat.h"
  30 #include "nfs4_fs.h"
  31 #include "fscache.h"
  32 #include "pnfs.h"
  33
  34 #include "nfstrace.h"
  35
  36 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  37
  38 #define MIN_POOL_WRITE          (32)
  39 #define MIN_POOL_COMMIT         (4)
  40
  41 /*
  42  * Local function declarations
  43  */
  44 static void nfs_redirty_request(struct nfs_page *req);
  45 static const struct rpc_call_ops nfs_write_common_ops;
  46 static const struct rpc_call_ops nfs_commit_ops;
  47 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
  48 static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
  49
  50 static struct kmem_cache *nfs_wdata_cachep;
  51 static mempool_t *nfs_wdata_mempool;
  52 static struct kmem_cache *nfs_cdata_cachep;
  53 static mempool_t *nfs_commit_mempool;
  54
  55 struct nfs_commit_data *nfs_commitdata_alloc(void)
  56 {
  57         struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOIO);
  58
  59         if (p) {
  60                 memset(p, 0, sizeof(*p));
  61                 INIT_LIST_HEAD(&p->pages);
  62         }
  63         return p;
  64 }
  65 EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
  66
  67 void nfs_commit_free(struct nfs_commit_data *p)
  68 {
  69         mempool_free(p, nfs_commit_mempool);
  70 }
  71 EXPORT_SYMBOL_GPL(nfs_commit_free);
  72
  73 struct nfs_write_header *nfs_writehdr_alloc(void)
  74 {
  75         struct nfs_write_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO);
  76
  77         if (p) {
  78                 struct nfs_pgio_header *hdr = &p->header;
  79
  80                 memset(p, 0, sizeof(*p));
  81                 INIT_LIST_HEAD(&hdr->pages);
  82                 INIT_LIST_HEAD(&hdr->rpc_list);
  83                 spin_lock_init(&hdr->lock);
  84                 atomic_set(&hdr->refcnt, 0);
  85                 hdr->verf = &p->verf;
  86         }
  87         return p;
  88 }
  89 EXPORT_SYMBOL_GPL(nfs_writehdr_alloc);
  90
  91 static struct nfs_write_data *nfs_writedata_alloc(struct nfs_pgio_header *hdr,
  92                                                   unsigned int pagecount)
  93 {
  94         struct nfs_write_data *data, *prealloc;
  95
  96         prealloc = &container_of(hdr, struct nfs_write_header, header)->rpc_data;
  97         if (prealloc->header == NULL)
  98                 data = prealloc;
  99         else
 100                 data = kzalloc(sizeof(*data), GFP_KERNEL);
 101         if (!data)
 102                 goto out;
 103
 104         if (nfs_pgarray_set(&data->pages, pagecount)) {
 105                 data->header = hdr;
 106                 atomic_inc(&hdr->refcnt);
 107         } else {
 108                 if (data != prealloc)
 109                         kfree(data);
 110                 data = NULL;
 111         }
 112 out:
 113         return data;
 114 }
 115
 116 void nfs_writehdr_free(struct nfs_pgio_header *hdr)
 117 {
 118         struct nfs_write_header *whdr = container_of(hdr, struct nfs_write_header, header);
 119         mempool_free(whdr, nfs_wdata_mempool);
 120 }
 121 EXPORT_SYMBOL_GPL(nfs_writehdr_free);
 122
 123 void nfs_writedata_release(struct nfs_write_data *wdata)
 124 {
 125         struct nfs_pgio_header *hdr = wdata->header;
 126         struct nfs_write_header *write_header = container_of(hdr, struct nfs_write_header, header);
 127
 128         put_nfs_open_context(wdata->args.context);
 129         if (wdata->pages.pagevec != wdata->pages.page_array)
 130                 kfree(wdata->pages.pagevec);
 131         if (wdata == &write_header->rpc_data) {
 132                 wdata->header = NULL;
 133                 wdata = NULL;
 134         }
 135         if (atomic_dec_and_test(&hdr->refcnt))
 136                 hdr->completion_ops->completion(hdr);
 137         /* Note: we only free the rpc_task after callbacks are done.
 138          * See the comment in rpc_free_task() for why
 139          */
 140         kfree(wdata);
 141 }
 142 EXPORT_SYMBOL_GPL(nfs_writedata_release);
 143
 144 static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
 145 {
 146         ctx->error = error;
 147         smp_wmb();
 148         set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 149 }
 150
 151 static struct nfs_page *
 152 nfs_page_find_request_locked(struct nfs_inode *nfsi, struct page *page)
 153 {
 154         struct nfs_page *req = NULL;
 155
 156         if (PagePrivate(page))
 157                 req = (struct nfs_page *)page_private(page);
 158         else if (unlikely(PageSwapCache(page))) {
 159                 struct nfs_page *freq, *t;
 160
 161                 /* Linearly search the commit list for the correct req */
 162                 list_for_each_entry_safe(freq, t, &nfsi->commit_info.list, wb_list) {
 163                         if (freq->wb_page == page) {
 164                                 req = freq;
 165                                 break;
 166                         }
 167                 }
 168         }
 169
 170         if (req)
 171                 kref_get(&req->wb_kref);
 172
 173         return req;
 174 }
 175
 176 static struct nfs_page *nfs_page_find_request(struct page *page)
 177 {
 178         struct inode *inode = page_file_mapping(page)->host;
 179         struct nfs_page *req = NULL;
 180
 181         spin_lock(&inode->i_lock);
 182         req = nfs_page_find_request_locked(NFS_I(inode), page);
 183         spin_unlock(&inode->i_lock);
 184         return req;
 185 }
 186
 187 /* Adjust the file length if we're writing beyond the end */
 188 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 189 {
 190         struct inode *inode = page_file_mapping(page)->host;
 191         loff_t end, i_size;
 192         pgoff_t end_index;
 193
 194         spin_lock(&inode->i_lock);
 195         i_size = i_size_read(inode);
 196         end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 197         if (i_size > 0 && page_file_index(page) < end_index)
 198                 goto out;
 199         end = page_file_offset(page) + ((loff_t)offset+count);
 200         if (i_size >= end)
 201                 goto out;
 202         i_size_write(inode, end);
 203         nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 204 out:
 205         spin_unlock(&inode->i_lock);
 206 }
 207
 208 /* A writeback failed: mark the page as bad, and invalidate the page cache */
 209 static void nfs_set_pageerror(struct page *page)
 210 {
 211         nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page));
 212 }
 213
 214 /* We can set the PG_uptodate flag if we see that a write request
 215  * covers the full page.
 216  */
 217 static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
 218 {
 219         if (PageUptodate(page))
 220                 return;
 221         if (base != 0)
 222                 return;
 223         if (count != nfs_page_length(page))
 224                 return;
 225         SetPageUptodate(page);
 226 }
 227
 228 static int wb_priority(struct writeback_control *wbc)
 229 {
 230         if (wbc->for_reclaim)
 231                 return FLUSH_HIGHPRI | FLUSH_STABLE;
 232         if (wbc->for_kupdate || wbc->for_background)
 233                 return FLUSH_LOWPRI | FLUSH_COND_STABLE;
 234         return FLUSH_COND_STABLE;
 235 }
 236
 237 /*
 238  * NFS congestion control
 239  */
 240
 241 int nfs_congestion_kb;
 242
 243 #define NFS_CONGESTION_ON_THRESH        (nfs_congestion_kb >> (PAGE_SHIFT-10))
 244 #define NFS_CONGESTION_OFF_THRESH       \
 245         (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 246
 247 static void nfs_set_page_writeback(struct page *page)
 248 {
 249         struct nfs_server *nfss = NFS_SERVER(page_file_mapping(page)->host);
 250         int ret = test_set_page_writeback(page);
 251
 252         WARN_ON_ONCE(ret != 0);
 253
 254         if (atomic_long_inc_return(&nfss->writeback) >
 255                         NFS_CONGESTION_ON_THRESH) {
 256                 set_bdi_congested(&nfss->backing_dev_info,
 257                                         BLK_RW_ASYNC);
 258         }
 259 }
 260
 261 static void nfs_end_page_writeback(struct page *page)
 262 {
 263         struct inode *inode = page_file_mapping(page)->host;
 264         struct nfs_server *nfss = NFS_SERVER(inode);
 265
 266         end_page_writeback(page);
 267         if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 268                 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
 269 }
 270
 271 static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
 272 {
 273         struct inode *inode = page_file_mapping(page)->host;
 274         struct nfs_page *req;
 275         int ret;
 276
 277         spin_lock(&inode->i_lock);
 278         for (;;) {
 279                 req = nfs_page_find_request_locked(NFS_I(inode), page);
 280                 if (req == NULL)
 281                         break;
 282                 if (nfs_lock_request(req))
 283                         break;
 284                 /* Note: If we hold the page lock, as is the case in nfs_writepage,
 285                  *       then the call to nfs_lock_request() will always
 286                  *       succeed provided that someone hasn't already marked the
 287                  *       request as dirty (in which case we don't care).
 288                  */
 289                 spin_unlock(&inode->i_lock);
 290                 if (!nonblock)
 291                         ret = nfs_wait_on_request(req);
 292                 else
 293                         ret = -EAGAIN;
 294                 nfs_release_request(req);
 295                 if (ret != 0)
 296                         return ERR_PTR(ret);
 297                 spin_lock(&inode->i_lock);
 298         }
 299         spin_unlock(&inode->i_lock);
 300         return req;
 301 }
 302
 303 /*
 304  * Find an associated nfs write request, and prepare to flush it out
 305  * May return an error if the user signalled nfs_wait_on_request().
 306  */
 307 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 308                                 struct page *page, bool nonblock)
 309 {
 310         struct nfs_page *req;
 311         int ret = 0;
 312
 313         req = nfs_find_and_lock_request(page, nonblock);
 314         if (!req)
 315                 goto out;
 316         ret = PTR_ERR(req);
 317         if (IS_ERR(req))
 318                 goto out;
 319
 320         nfs_set_page_writeback(page);
 321         WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
 322
 323         ret = 0;
 324         if (!nfs_pageio_add_request(pgio, req)) {
 325                 nfs_redirty_request(req);
 326                 ret = pgio->pg_error;
 327         }
 328 out:
 329         return ret;
 330 }
 331
 332 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
 333 {
 334         struct inode *inode = page_file_mapping(page)->host;
 335         int ret;
 336
 337         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 338         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 339
 340         nfs_pageio_cond_complete(pgio, page_file_index(page));
 341         ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
 342         if (ret == -EAGAIN) {
 343                 redirty_page_for_writepage(wbc, page);
 344                 ret = 0;
 345         }
 346         return ret;
 347 }
 348
 349 /*
 350  * Write an mmapped page to the server.
 351  */
 352 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 353 {
 354         struct nfs_pageio_descriptor pgio;
 355         int err;
 356
 357         NFS_PROTO(page_file_mapping(page)->host)->write_pageio_init(&pgio,
 358                                                           page->mapping->host,
 359                                                           wb_priority(wbc),
 360                                                           &nfs_async_write_completion_ops);
 361         err = nfs_do_writepage(page, wbc, &pgio);
 362         nfs_pageio_complete(&pgio);
 363         if (err < 0)
 364                 return err;
 365         if (pgio.pg_error < 0)
 366                 return pgio.pg_error;
 367         return 0;
 368 }
 369
 370 int nfs_writepage(struct page *page, struct writeback_control *wbc)
 371 {
 372         int ret;
 373
 374         ret = nfs_writepage_locked(page, wbc);
 375         unlock_page(page);
 376         return ret;
 377 }
 378
 379 static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
 380 {
 381         int ret;
 382
 383         ret = nfs_do_writepage(page, wbc, data);
 384         unlock_page(page);
 385         return ret;
 386 }
 387
 388 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 389 {
 390         struct inode *inode = mapping->host;
 391         unsigned long *bitlock = &NFS_I(inode)->flags;
 392         struct nfs_pageio_descriptor pgio;
 393         int err;
 394
 395         /* Stop dirtying of new pages while we sync */
 396         err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
 397                         nfs_wait_bit_killable, TASK_KILLABLE);
 398         if (err)
 399                 goto out_err;
 400
 401         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 402
 403         NFS_PROTO(inode)->write_pageio_init(&pgio, inode, wb_priority(wbc), &nfs_async_write_completion_ops);
 404         err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
 405         nfs_pageio_complete(&pgio);
 406
 407         clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
 408         smp_mb__after_clear_bit();
 409         wake_up_bit(bitlock, NFS_INO_FLUSHING);
 410
 411         if (err < 0)
 412                 goto out_err;
 413         err = pgio.pg_error;
 414         if (err < 0)
 415                 goto out_err;
 416         return 0;
 417 out_err:
 418         return err;
 419 }
 420
 421 /*
 422  * Insert a write request into an inode
 423  */
 424 static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 425 {
 426         struct nfs_inode *nfsi = NFS_I(inode);
 427
 428         /* Lock the request! */
 429         nfs_lock_request(req);
 430
 431         spin_lock(&inode->i_lock);
 432         if (!nfsi->npages && NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
 433                 inode->i_version++;
 434         /*
 435          * Swap-space should not get truncated. Hence no need to plug the race
 436          * with invalidate/truncate.
 437          */
 438         if (likely(!PageSwapCache(req->wb_page))) {
 439                 set_bit(PG_MAPPED, &req->wb_flags);
 440                 SetPagePrivate(req->wb_page);
 441                 set_page_private(req->wb_page, (unsigned long)req);
 442         }
 443         nfsi->npages++;
 444         kref_get(&req->wb_kref);
 445         spin_unlock(&inode->i_lock);
 446 }
 447
 448 /*
 449  * Remove a write request from an inode
 450  */
 451 static void nfs_inode_remove_request(struct nfs_page *req)
 452 {
 453         struct inode *inode = req->wb_context->dentry->d_inode;
 454         struct nfs_inode *nfsi = NFS_I(inode);
 455
 456         spin_lock(&inode->i_lock);
 457         if (likely(!PageSwapCache(req->wb_page))) {
 458                 set_page_private(req->wb_page, 0);
 459                 ClearPagePrivate(req->wb_page);
 460                 clear_bit(PG_MAPPED, &req->wb_flags);
 461         }
 462         nfsi->npages--;
 463         spin_unlock(&inode->i_lock);
 464         nfs_release_request(req);
 465 }
 466
 467 static void
 468 nfs_mark_request_dirty(struct nfs_page *req)
 469 {
 470         __set_page_dirty_nobuffers(req->wb_page);
 471 }
 472
 473 #if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4)
 474 /**
 475  * nfs_request_add_commit_list - add request to a commit list
 476  * @req: pointer to a struct nfs_page
 477  * @dst: commit list head
 478  * @cinfo: holds list lock and accounting info
 479  *
 480  * This sets the PG_CLEAN bit, updates the cinfo count of
 481  * number of outstanding requests requiring a commit as well as
 482  * the MM page stats.
 483  *
 484  * The caller must _not_ hold the cinfo->lock, but must be
 485  * holding the nfs_page lock.
 486  */
 487 void
 488 nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst,
 489                             struct nfs_commit_info *cinfo)
 490 {
 491         set_bit(PG_CLEAN, &(req)->wb_flags);
 492         spin_lock(cinfo->lock);
 493         nfs_list_add_request(req, dst);
 494         cinfo->mds->ncommit++;
 495         spin_unlock(cinfo->lock);
 496         if (!cinfo->dreq) {
 497                 inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 498                 inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
 499                              BDI_RECLAIMABLE);
 500                 __mark_inode_dirty(req->wb_context->dentry->d_inode,
 501                                    I_DIRTY_DATASYNC);
 502         }
 503 }
 504 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
 505
 506 /**
 507  * nfs_request_remove_commit_list - Remove request from a commit list
 508  * @req: pointer to a nfs_page
 509  * @cinfo: holds list lock and accounting info
 510  *
 511  * This clears the PG_CLEAN bit, and updates the cinfo's count of
 512  * number of outstanding requests requiring a commit
 513  * It does not update the MM page stats.
 514  *
 515  * The caller _must_ hold the cinfo->lock and the nfs_page lock.
 516  */
 517 void
 518 nfs_request_remove_commit_list(struct nfs_page *req,
 519                                struct nfs_commit_info *cinfo)
 520 {
 521         if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
 522                 return;
 523         nfs_list_remove_request(req);
 524         cinfo->mds->ncommit--;
 525 }
 526 EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
 527
 528 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 529                                       struct inode *inode)
 530 {
 531         cinfo->lock = &inode->i_lock;
 532         cinfo->mds = &NFS_I(inode)->commit_info;
 533         cinfo->ds = pnfs_get_ds_info(inode);
 534         cinfo->dreq = NULL;
 535         cinfo->completion_ops = &nfs_commit_completion_ops;
 536 }
 537
 538 void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 539                     struct inode *inode,
 540                     struct nfs_direct_req *dreq)
 541 {
 542         if (dreq)
 543                 nfs_init_cinfo_from_dreq(cinfo, dreq);
 544         else
 545                 nfs_init_cinfo_from_inode(cinfo, inode);
 546 }
 547 EXPORT_SYMBOL_GPL(nfs_init_cinfo);
 548
 549 /*
 550  * Add a request to the inode's commit list.
 551  */
 552 void
 553 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 554                         struct nfs_commit_info *cinfo)
 555 {
 556         if (pnfs_mark_request_commit(req, lseg, cinfo))
 557                 return;
 558         nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo);
 559 }
 560
 561 static void
 562 nfs_clear_page_commit(struct page *page)
 563 {
 564         dec_zone_page_state(page, NR_UNSTABLE_NFS);
 565         dec_bdi_stat(page_file_mapping(page)->backing_dev_info, BDI_RECLAIMABLE);
 566 }
 567
 568 static void
 569 nfs_clear_request_commit(struct nfs_page *req)
 570 {
 571         if (test_bit(PG_CLEAN, &req->wb_flags)) {
 572                 struct inode *inode = req->wb_context->dentry->d_inode;
 573                 struct nfs_commit_info cinfo;
 574
 575                 nfs_init_cinfo_from_inode(&cinfo, inode);
 576                 if (!pnfs_clear_request_commit(req, &cinfo)) {
 577                         spin_lock(cinfo.lock);
 578                         nfs_request_remove_commit_list(req, &cinfo);
 579                         spin_unlock(cinfo.lock);
 580                 }
 581                 nfs_clear_page_commit(req->wb_page);
 582         }
 583 }
 584
 585 static inline
 586 int nfs_write_need_commit(struct nfs_write_data *data)
 587 {
 588         if (data->verf.committed == NFS_DATA_SYNC)
 589                 return data->header->lseg == NULL;
 590         return data->verf.committed != NFS_FILE_SYNC;
 591 }
 592
 593 #else
 594 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 595                                       struct inode *inode)
 596 {
 597 }
 598
 599 void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 600                     struct inode *inode,
 601                     struct nfs_direct_req *dreq)
 602 {
 603 }
 604
 605 void
 606 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 607                         struct nfs_commit_info *cinfo)
 608 {
 609 }
 610
 611 static void
 612 nfs_clear_request_commit(struct nfs_page *req)
 613 {
 614 }
 615
 616 static inline
 617 int nfs_write_need_commit(struct nfs_write_data *data)
 618 {
 619         return 0;
 620 }
 621
 622 #endif
 623
 624 static void nfs_write_completion(struct nfs_pgio_header *hdr)
 625 {
 626         struct nfs_commit_info cinfo;
 627         unsigned long bytes = 0;
 628
 629         if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 630                 goto out;
 631         nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
 632         while (!list_empty(&hdr->pages)) {
 633                 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 634
 635                 bytes += req->wb_bytes;
 636                 nfs_list_remove_request(req);
 637                 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
 638                     (hdr->good_bytes < bytes)) {
 639                         nfs_set_pageerror(req->wb_page);
 640                         nfs_context_set_write_error(req->wb_context, hdr->error);
 641                         goto remove_req;
 642                 }
 643                 if (test_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags)) {
 644                         nfs_mark_request_dirty(req);
 645                         goto next;
 646                 }
 647                 if (test_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags)) {
 648                         memcpy(&req->wb_verf, &hdr->verf->verifier, sizeof(req->wb_verf));
 649                         nfs_mark_request_commit(req, hdr->lseg, &cinfo);
 650                         goto next;
 651                 }
 652 remove_req:
 653                 nfs_inode_remove_request(req);
 654 next:
 655                 nfs_unlock_request(req);
 656                 nfs_end_page_writeback(req->wb_page);
 657                 nfs_release_request(req);
 658         }
 659 out:
 660         hdr->release(hdr);
 661 }
 662
 663 #if  IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4)
 664 static unsigned long
 665 nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
 666 {
 667         return cinfo->mds->ncommit;
 668 }
 669
 670 /* cinfo->lock held by caller */
 671 int
 672 nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
 673                      struct nfs_commit_info *cinfo, int max)
 674 {
 675         struct nfs_page *req, *tmp;
 676         int ret = 0;
 677
 678         list_for_each_entry_safe(req, tmp, src, wb_list) {
 679                 if (!nfs_lock_request(req))
 680                         continue;
 681                 kref_get(&req->wb_kref);
 682                 if (cond_resched_lock(cinfo->lock))
 683                         list_safe_reset_next(req, tmp, wb_list);
 684                 nfs_request_remove_commit_list(req, cinfo);
 685                 nfs_list_add_request(req, dst);
 686                 ret++;
 687                 if ((ret == max) && !cinfo->dreq)
 688                         break;
 689         }
 690         return ret;
 691 }
 692
 693 /*
 694  * nfs_scan_commit - Scan an inode for commit requests
 695  * @inode: NFS inode to scan
 696  * @dst: mds destination list
 697  * @cinfo: mds and ds lists of reqs ready to commit
 698  *
 699  * Moves requests from the inode's 'commit' request list.
 700  * The requests are *not* checked to ensure that they form a contiguous set.
 701  */
 702 int
 703 nfs_scan_commit(struct inode *inode, struct list_head *dst,
 704                 struct nfs_commit_info *cinfo)
 705 {
 706         int ret = 0;
 707
 708         spin_lock(cinfo->lock);
 709         if (cinfo->mds->ncommit > 0) {
 710                 const int max = INT_MAX;
 711
 712                 ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
 713                                            cinfo, max);
 714                 ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
 715         }
 716         spin_unlock(cinfo->lock);
 717         return ret;
 718 }
 719
 720 #else
 721 static unsigned long nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
 722 {
 723         return 0;
 724 }
 725
 726 int nfs_scan_commit(struct inode *inode, struct list_head *dst,
 727                     struct nfs_commit_info *cinfo)
 728 {
 729         return 0;
 730 }
 731 #endif
 732
 733 /*
 734  * Search for an existing write request, and attempt to update
 735  * it to reflect a new dirty region on a given page.
 736  *
 737  * If the attempt fails, then the existing request is flushed out
 738  * to disk.
 739  */
 740 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
 741                 struct page *page,
 742                 unsigned int offset,
 743                 unsigned int bytes)
 744 {
 745         struct nfs_page *req;
 746         unsigned int rqend;
 747         unsigned int end;
 748         int error;
 749
 750         if (!PagePrivate(page))
 751                 return NULL;
 752
 753         end = offset + bytes;
 754         spin_lock(&inode->i_lock);
 755
 756         for (;;) {
 757                 req = nfs_page_find_request_locked(NFS_I(inode), page);
 758                 if (req == NULL)
 759                         goto out_unlock;
 760
 761                 rqend = req->wb_offset + req->wb_bytes;
 762                 /*
 763                  * Tell the caller to flush out the request if
 764                  * the offsets are non-contiguous.
 765                  * Note: nfs_flush_incompatible() will already
 766                  * have flushed out requests having wrong owners.
 767                  */
 768                 if (offset > rqend
 769                     || end < req->wb_offset)
 770                         goto out_flushme;
 771
 772                 if (nfs_lock_request(req))
 773                         break;
 774
 775                 /* The request is locked, so wait and then retry */
 776                 spin_unlock(&inode->i_lock);
 777                 error = nfs_wait_on_request(req);
 778                 nfs_release_request(req);
 779                 if (error != 0)
 780                         goto out_err;
 781                 spin_lock(&inode->i_lock);
 782         }
 783
 784         /* Okay, the request matches. Update the region */
 785         if (offset < req->wb_offset) {
 786                 req->wb_offset = offset;
 787                 req->wb_pgbase = offset;
 788         }
 789         if (end > rqend)
 790                 req->wb_bytes = end - req->wb_offset;
 791         else
 792                 req->wb_bytes = rqend - req->wb_offset;
 793 out_unlock:
 794         spin_unlock(&inode->i_lock);
 795         if (req)
 796                 nfs_clear_request_commit(req);
 797         return req;
 798 out_flushme:
 799         spin_unlock(&inode->i_lock);
 800         nfs_release_request(req);
 801         error = nfs_wb_page(inode, page);
 802 out_err:
 803         return ERR_PTR(error);
 804 }
 805
 806 /*
 807  * Try to update an existing write request, or create one if there is none.
 808  *
 809  * Note: Should always be called with the Page Lock held to prevent races
 810  * if we have to add a new request. Also assumes that the caller has
 811  * already called nfs_flush_incompatible() if necessary.
 812  */
 813 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
 814                 struct page *page, unsigned int offset, unsigned int bytes)
 815 {
 816         struct inode *inode = page_file_mapping(page)->host;
 817         struct nfs_page *req;
 818
 819         req = nfs_try_to_update_request(inode, page, offset, bytes);
 820         if (req != NULL)
 821                 goto out;
 822         req = nfs_create_request(ctx, inode, page, offset, bytes);
 823         if (IS_ERR(req))
 824                 goto out;
 825         nfs_inode_add_request(inode, req);
 826 out:
 827         return req;
 828 }
 829
 830 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 831                 unsigned int offset, unsigned int count)
 832 {
 833         struct nfs_page *req;
 834
 835         req = nfs_setup_write_request(ctx, page, offset, count);
 836         if (IS_ERR(req))
 837                 return PTR_ERR(req);
 838         /* Update file length */
 839         nfs_grow_file(page, offset, count);
 840         nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
 841         nfs_mark_request_dirty(req);
 842         nfs_unlock_and_release_request(req);
 843         return 0;
 844 }
 845
 846 int nfs_flush_incompatible(struct file *file, struct page *page)
 847 {
 848         struct nfs_open_context *ctx = nfs_file_open_context(file);
 849         struct nfs_lock_context *l_ctx;
 850         struct nfs_page *req;
 851         int do_flush, status;
 852         /*
 853          * Look for a request corresponding to this page. If there
 854          * is one, and it belongs to another file, we flush it out
 855          * before we try to copy anything into the page. Do this
 856          * due to the lack of an ACCESS-type call in NFSv2.
 857          * Also do the same if we find a request from an existing
 858          * dropped page.
 859          */
 860         do {
 861                 req = nfs_page_find_request(page);
 862                 if (req == NULL)
 863                         return 0;
 864                 l_ctx = req->wb_lock_context;
 865                 do_flush = req->wb_page != page || req->wb_context != ctx;
 866                 if (l_ctx && ctx->dentry->d_inode->i_flock != NULL) {
 867                         do_flush |= l_ctx->lockowner.l_owner != current->files
 868                                 || l_ctx->lockowner.l_pid != current->tgid;
 869                 }
 870                 nfs_release_request(req);
 871                 if (!do_flush)
 872                         return 0;
 873                 status = nfs_wb_page(page_file_mapping(page)->host, page);
 874         } while (status == 0);
 875         return status;
 876 }
 877
 878 /*
 879  * Avoid buffered writes when a open context credential's key would
 880  * expire soon.
 881  *
 882  * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
 883  *
 884  * Return 0 and set a credential flag which triggers the inode to flush
 885  * and performs  NFS_FILE_SYNC writes if the key will expired within
 886  * RPC_KEY_EXPIRE_TIMEO.
 887  */
 888 int
 889 nfs_key_timeout_notify(struct file *filp, struct inode *inode)
 890 {
 891         struct nfs_open_context *ctx = nfs_file_open_context(filp);
 892         struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
 893
 894         return rpcauth_key_timeout_notify(auth, ctx->cred);
 895 }
 896
 897 /*
 898  * Test if the open context credential key is marked to expire soon.
 899  */
 900 bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx)
 901 {
 902         return rpcauth_cred_key_to_expire(ctx->cred);
 903 }
 904
 905 /*
 906  * If the page cache is marked as unsafe or invalid, then we can't rely on
 907  * the PageUptodate() flag. In this case, we will need to turn off
 908  * write optimisations that depend on the page contents being correct.
 909  */
 910 static bool nfs_write_pageuptodate(struct page *page, struct inode *inode)
 911 {
 912         if (nfs_have_delegated_attributes(inode))
 913                 goto out;
 914         if (NFS_I(inode)->cache_validity & (NFS_INO_INVALID_DATA|NFS_INO_REVAL_PAGECACHE))
 915                 return false;
 916 out:
 917         return PageUptodate(page) != 0;
 918 }
 919
 920 /* If we know the page is up to date, and we're not using byte range locks (or
 921  * if we have the whole file locked for writing), it may be more efficient to
 922  * extend the write to cover the entire page in order to avoid fragmentation
 923  * inefficiencies.
 924  *
 925  * If the file is opened for synchronous writes or if we have a write delegation
 926  * from the server then we can just skip the rest of the checks.
 927  */
 928 static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode)
 929 {
 930         if (file->f_flags & O_DSYNC)
 931                 return 0;
 932         if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
 933                 return 1;
 934         if (nfs_write_pageuptodate(page, inode) && (inode->i_flock == NULL ||
 935                         (inode->i_flock->fl_start == 0 &&
 936                         inode->i_flock->fl_end == OFFSET_MAX &&
 937                         inode->i_flock->fl_type != F_RDLCK)))
 938                 return 1;
 939         return 0;
 940 }
 941
 942 /*
 943  * Update and possibly write a cached page of an NFS file.
 944  *
 945  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
 946  * things with a page scheduled for an RPC call (e.g. invalidate it).
 947  */
 948 int nfs_updatepage(struct file *file, struct page *page,
 949                 unsigned int offset, unsigned int count)
 950 {
 951         struct nfs_open_context *ctx = nfs_file_open_context(file);
 952         struct inode    *inode = page_file_mapping(page)->host;
 953         int             status = 0;
 954
 955         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 956
 957         dprintk("NFS:       nfs_updatepage(%pD2 %d@%lld)\n",
 958                 file, count, (long long)(page_file_offset(page) + offset));
 959
 960         if (nfs_can_extend_write(file, page, inode)) {
 961                 count = max(count + offset, nfs_page_length(page));
 962                 offset = 0;
 963         }
 964
 965         status = nfs_writepage_setup(ctx, page, offset, count);
 966         if (status < 0)
 967                 nfs_set_pageerror(page);
 968         else
 969                 __set_page_dirty_nobuffers(page);
 970
 971         dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
 972                         status, (long long)i_size_read(inode));
 973         return status;
 974 }
 975
 976 static int flush_task_priority(int how)
 977 {
 978         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
 979                 case FLUSH_HIGHPRI:
 980                         return RPC_PRIORITY_HIGH;
 981                 case FLUSH_LOWPRI:
 982                         return RPC_PRIORITY_LOW;
 983         }
 984         return RPC_PRIORITY_NORMAL;
 985 }
 986
 987 int nfs_initiate_write(struct rpc_clnt *clnt,
 988                        struct nfs_write_data *data,
 989                        const struct rpc_call_ops *call_ops,
 990                        int how, int flags)
 991 {
 992         struct inode *inode = data->header->inode;
 993         int priority = flush_task_priority(how);
 994         struct rpc_task *task;
 995         struct rpc_message msg = {
 996                 .rpc_argp = &data->args,
 997                 .rpc_resp = &data->res,
 998                 .rpc_cred = data->header->cred,
 999         };
1000         struct rpc_task_setup task_setup_data = {
1001                 .rpc_client = clnt,
1002                 .task = &data->task,
1003                 .rpc_message = &msg,
1004                 .callback_ops = call_ops,
1005                 .callback_data = data,
1006                 .workqueue = nfsiod_workqueue,
1007                 .flags = RPC_TASK_ASYNC | flags,
1008                 .priority = priority,
1009         };
1010         int ret = 0;
1011
1012         /* Set up the initial task struct.  */
1013         NFS_PROTO(inode)->write_setup(data, &msg);
1014
1015         dprintk("NFS: %5u initiated write call "
1016                 "(req %s/%lld, %u bytes @ offset %llu)\n",
1017                 data->task.tk_pid,
1018                 inode->i_sb->s_id,
1019                 (long long)NFS_FILEID(inode),
1020                 data->args.count,
1021                 (unsigned long long)data->args.offset);
1022
1023         nfs4_state_protect_write(NFS_SERVER(inode)->nfs_client,
1024                                  &task_setup_data.rpc_client, &msg, data);
1025
1026         task = rpc_run_task(&task_setup_data);
1027         if (IS_ERR(task)) {
1028                 ret = PTR_ERR(task);
1029                 goto out;
1030         }
1031         if (how & FLUSH_SYNC) {
1032                 ret = rpc_wait_for_completion_task(task);
1033                 if (ret == 0)
1034                         ret = task->tk_status;
1035         }
1036         rpc_put_task(task);
1037 out:
1038         return ret;
1039 }
1040 EXPORT_SYMBOL_GPL(nfs_initiate_write);
1041
1042 /*
1043  * Set up the argument/result storage required for the RPC call.
1044  */
1045 static void nfs_write_rpcsetup(struct nfs_write_data *data,
1046                 unsigned int count, unsigned int offset,
1047                 int how, struct nfs_commit_info *cinfo)
1048 {
1049         struct nfs_page *req = data->header->req;
1050
1051         /* Set up the RPC argument and reply structs
1052          * NB: take care not to mess about with data->commit et al. */
1053
1054         data->args.fh     = NFS_FH(data->header->inode);
1055         data->args.offset = req_offset(req) + offset;
1056         /* pnfs_set_layoutcommit needs this */
1057         data->mds_offset = data->args.offset;
1058         data->args.pgbase = req->wb_pgbase + offset;
1059         data->args.pages  = data->pages.pagevec;
1060         data->args.count  = count;
1061         data->args.context = get_nfs_open_context(req->wb_context);
1062         data->args.lock_context = req->wb_lock_context;
1063         data->args.stable  = NFS_UNSTABLE;
1064         switch (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
1065         case 0:
1066                 break;
1067         case FLUSH_COND_STABLE:
1068                 if (nfs_reqs_to_commit(cinfo))
1069                         break;
1070         default:
1071                 data->args.stable = NFS_FILE_SYNC;
1072         }
1073
1074         data->res.fattr   = &data->fattr;
1075         data->res.count   = count;
1076         data->res.verf    = &data->verf;
1077         nfs_fattr_init(&data->fattr);
1078 }
1079
1080 static int nfs_do_write(struct nfs_write_data *data,
1081                 const struct rpc_call_ops *call_ops,
1082                 int how)
1083 {
1084         struct inode *inode = data->header->inode;
1085
1086         return nfs_initiate_write(NFS_CLIENT(inode), data, call_ops, how, 0);
1087 }
1088
1089 static int nfs_do_multiple_writes(struct list_head *head,
1090                 const struct rpc_call_ops *call_ops,
1091                 int how)
1092 {
1093         struct nfs_write_data *data;
1094         int ret = 0;
1095
1096         while (!list_empty(head)) {
1097                 int ret2;
1098
1099                 data = list_first_entry(head, struct nfs_write_data, list);
1100                 list_del_init(&data->list);
1101
1102                 ret2 = nfs_do_write(data, call_ops, how);
1103                  if (ret == 0)
1104                          ret = ret2;
1105         }
1106         return ret;
1107 }
1108
1109 /* If a nfs_flush_* function fails, it should remove reqs from @head and
1110  * call this on each, which will prepare them to be retried on next
1111  * writeback using standard nfs.
1112  */
1113 static void nfs_redirty_request(struct nfs_page *req)
1114 {
1115         nfs_mark_request_dirty(req);
1116         nfs_unlock_request(req);
1117         nfs_end_page_writeback(req->wb_page);
1118         nfs_release_request(req);
1119 }
1120
1121 static void nfs_async_write_error(struct list_head *head)
1122 {
1123         struct nfs_page *req;
1124
1125         while (!list_empty(head)) {
1126                 req = nfs_list_entry(head->next);
1127                 nfs_list_remove_request(req);
1128                 nfs_redirty_request(req);
1129         }
1130 }
1131
1132 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1133         .error_cleanup = nfs_async_write_error,
1134         .completion = nfs_write_completion,
1135 };
1136
1137 static void nfs_flush_error(struct nfs_pageio_descriptor *desc,
1138                 struct nfs_pgio_header *hdr)
1139 {
1140         set_bit(NFS_IOHDR_REDO, &hdr->flags);
1141         while (!list_empty(&hdr->rpc_list)) {
1142                 struct nfs_write_data *data = list_first_entry(&hdr->rpc_list,
1143                                 struct nfs_write_data, list);
1144                 list_del(&data->list);
1145                 nfs_writedata_release(data);
1146         }
1147         desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1148 }
1149
1150 /*
1151  * Generate multiple small requests to write out a single
1152  * contiguous dirty area on one page.
1153  */
1154 static int nfs_flush_multi(struct nfs_pageio_descriptor *desc,
1155                            struct nfs_pgio_header *hdr)
1156 {
1157         struct nfs_page *req = hdr->req;
1158         struct page *page = req->wb_page;
1159         struct nfs_write_data *data;
1160         size_t wsize = desc->pg_bsize, nbytes;
1161         unsigned int offset;
1162         int requests = 0;
1163         struct nfs_commit_info cinfo;
1164
1165         nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
1166
1167         if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1168             (desc->pg_moreio || nfs_reqs_to_commit(&cinfo) ||
1169              desc->pg_count > wsize))
1170                 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1171
1172
1173         offset = 0;
1174         nbytes = desc->pg_count;
1175         do {
1176                 size_t len = min(nbytes, wsize);
1177
1178                 data = nfs_writedata_alloc(hdr, 1);
1179                 if (!data) {
1180                         nfs_flush_error(desc, hdr);
1181                         return -ENOMEM;
1182                 }
1183                 data->pages.pagevec[0] = page;
1184                 nfs_write_rpcsetup(data, len, offset, desc->pg_ioflags, &cinfo);
1185                 list_add(&data->list, &hdr->rpc_list);
1186                 requests++;
1187                 nbytes -= len;
1188                 offset += len;
1189         } while (nbytes != 0);
1190         nfs_list_remove_request(req);
1191         nfs_list_add_request(req, &hdr->pages);
1192         desc->pg_rpc_callops = &nfs_write_common_ops;
1193         return 0;
1194 }
1195
1196 /*
1197  * Create an RPC task for the given write request and kick it.
1198  * The page must have been locked by the caller.
1199  *
1200  * It may happen that the page we're passed is not marked dirty.
1201  * This is the case if nfs_updatepage detects a conflicting request
1202  * that has been written but not committed.
1203  */
1204 static int nfs_flush_one(struct nfs_pageio_descriptor *desc,
1205                          struct nfs_pgio_header *hdr)
1206 {
1207         struct nfs_page         *req;
1208         struct page             **pages;
1209         struct nfs_write_data   *data;
1210         struct list_head *head = &desc->pg_list;
1211         struct nfs_commit_info cinfo;
1212
1213         data = nfs_writedata_alloc(hdr, nfs_page_array_len(desc->pg_base,
1214                                                            desc->pg_count));
1215         if (!data) {
1216                 nfs_flush_error(desc, hdr);
1217                 return -ENOMEM;
1218         }
1219
1220         nfs_init_cinfo(&cinfo, desc->pg_inode, desc->pg_dreq);
1221         pages = data->pages.pagevec;
1222         while (!list_empty(head)) {
1223                 req = nfs_list_entry(head->next);
1224                 nfs_list_remove_request(req);
1225                 nfs_list_add_request(req, &hdr->pages);
1226                 *pages++ = req->wb_page;
1227         }
1228
1229         if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1230             (desc->pg_moreio || nfs_reqs_to_commit(&cinfo)))
1231                 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1232
1233         /* Set up the argument struct */
1234         nfs_write_rpcsetup(data, desc->pg_count, 0, desc->pg_ioflags, &cinfo);
1235         list_add(&data->list, &hdr->rpc_list);
1236         desc->pg_rpc_callops = &nfs_write_common_ops;
1237         return 0;
1238 }
1239
1240 int nfs_generic_flush(struct nfs_pageio_descriptor *desc,
1241                       struct nfs_pgio_header *hdr)
1242 {
1243         if (desc->pg_bsize < PAGE_CACHE_SIZE)
1244                 return nfs_flush_multi(desc, hdr);
1245         return nfs_flush_one(desc, hdr);
1246 }
1247 EXPORT_SYMBOL_GPL(nfs_generic_flush);
1248
1249 static int nfs_generic_pg_writepages(struct nfs_pageio_descriptor *desc)
1250 {
1251         struct nfs_write_header *whdr;
1252         struct nfs_pgio_header *hdr;
1253         int ret;
1254
1255         whdr = nfs_writehdr_alloc();
1256         if (!whdr) {
1257                 desc->pg_completion_ops->error_cleanup(&desc->pg_list);
1258                 return -ENOMEM;
1259         }
1260         hdr = &whdr->header;
1261         nfs_pgheader_init(desc, hdr, nfs_writehdr_free);
1262         atomic_inc(&hdr->refcnt);
1263         ret = nfs_generic_flush(desc, hdr);
1264         if (ret == 0)
1265                 ret = nfs_do_multiple_writes(&hdr->rpc_list,
1266                                              desc->pg_rpc_callops,
1267                                              desc->pg_ioflags);
1268         if (atomic_dec_and_test(&hdr->refcnt))
1269                 hdr->completion_ops->completion(hdr);
1270         return ret;
1271 }
1272
1273 static const struct nfs_pageio_ops nfs_pageio_write_ops = {
1274         .pg_test = nfs_generic_pg_test,
1275         .pg_doio = nfs_generic_pg_writepages,
1276 };
1277
1278 void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1279                                struct inode *inode, int ioflags,
1280                                const struct nfs_pgio_completion_ops *compl_ops)
1281 {
1282         nfs_pageio_init(pgio, inode, &nfs_pageio_write_ops, compl_ops,
1283                                 NFS_SERVER(inode)->wsize, ioflags);
1284 }
1285 EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1286
1287 void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1288 {
1289         pgio->pg_ops = &nfs_pageio_write_ops;
1290         pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1291 }
1292 EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1293
1294
1295 void nfs_write_prepare(struct rpc_task *task, void *calldata)
1296 {
1297         struct nfs_write_data *data = calldata;
1298         int err;
1299         err = NFS_PROTO(data->header->inode)->write_rpc_prepare(task, data);
1300         if (err)
1301                 rpc_exit(task, err);
1302 }
1303
1304 void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1305 {
1306         struct nfs_commit_data *data = calldata;
1307
1308         NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1309 }
1310
1311 /*
1312  * Handle a write reply that flushes a whole page.
1313  *
1314  * FIXME: There is an inherent race with invalidate_inode_pages and
1315  *        writebacks since the page->count is kept > 1 for as long
1316  *        as the page has a write request pending.
1317  */
1318 static void nfs_writeback_done_common(struct rpc_task *task, void *calldata)
1319 {
1320         struct nfs_write_data   *data = calldata;
1321
1322         nfs_writeback_done(task, data);
1323 }
1324
1325 static void nfs_writeback_release_common(void *calldata)
1326 {
1327         struct nfs_write_data   *data = calldata;
1328         struct nfs_pgio_header *hdr = data->header;
1329         int status = data->task.tk_status;
1330
1331         if ((status >= 0) && nfs_write_need_commit(data)) {
1332                 spin_lock(&hdr->lock);
1333                 if (test_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags))
1334                         ; /* Do nothing */
1335                 else if (!test_and_set_bit(NFS_IOHDR_NEED_COMMIT, &hdr->flags))
1336                         memcpy(hdr->verf, &data->verf, sizeof(*hdr->verf));
1337                 else if (memcmp(hdr->verf, &data->verf, sizeof(*hdr->verf)))
1338                         set_bit(NFS_IOHDR_NEED_RESCHED, &hdr->flags);
1339                 spin_unlock(&hdr->lock);
1340         }
1341         nfs_writedata_release(data);
1342 }
1343
1344 static const struct rpc_call_ops nfs_write_common_ops = {
1345         .rpc_call_prepare = nfs_write_prepare,
1346         .rpc_call_done = nfs_writeback_done_common,
1347         .rpc_release = nfs_writeback_release_common,
1348 };
1349
1350
1351 /*
1352  * This function is called when the WRITE call is complete.
1353  */
1354 void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1355 {
1356         struct nfs_writeargs    *argp = &data->args;
1357         struct nfs_writeres     *resp = &data->res;
1358         struct inode            *inode = data->header->inode;
1359         int status;
1360
1361         dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1362                 task->tk_pid, task->tk_status);
1363
1364         /*
1365          * ->write_done will attempt to use post-op attributes to detect
1366          * conflicting writes by other clients.  A strict interpretation
1367          * of close-to-open would allow us to continue caching even if
1368          * another writer had changed the file, but some applications
1369          * depend on tighter cache coherency when writing.
1370          */
1371         status = NFS_PROTO(inode)->write_done(task, data);
1372         if (status != 0)
1373                 return;
1374         nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1375
1376 #if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4)
1377         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1378                 /* We tried a write call, but the server did not
1379                  * commit data to stable storage even though we
1380                  * requested it.
1381                  * Note: There is a known bug in Tru64 < 5.0 in which
1382                  *       the server reports NFS_DATA_SYNC, but performs
1383                  *       NFS_FILE_SYNC. We therefore implement this checking
1384                  *       as a dprintk() in order to avoid filling syslog.
1385                  */
1386                 static unsigned long    complain;
1387
1388                 /* Note this will print the MDS for a DS write */
1389                 if (time_before(complain, jiffies)) {
1390                         dprintk("NFS:       faulty NFS server %s:"
1391                                 " (committed = %d) != (stable = %d)\n",
1392                                 NFS_SERVER(inode)->nfs_client->cl_hostname,
1393                                 resp->verf->committed, argp->stable);
1394                         complain = jiffies + 300 * HZ;
1395                 }
1396         }
1397 #endif
1398         if (task->tk_status < 0)
1399                 nfs_set_pgio_error(data->header, task->tk_status, argp->offset);
1400         else if (resp->count < argp->count) {
1401                 static unsigned long    complain;
1402
1403                 /* This a short write! */
1404                 nfs_inc_stats(inode, NFSIOS_SHORTWRITE);
1405
1406                 /* Has the server at least made some progress? */
1407                 if (resp->count == 0) {
1408                         if (time_before(complain, jiffies)) {
1409                                 printk(KERN_WARNING
1410                                        "NFS: Server wrote zero bytes, expected %u.\n",
1411                                        argp->count);
1412                                 complain = jiffies + 300 * HZ;
1413                         }
1414                         nfs_set_pgio_error(data->header, -EIO, argp->offset);
1415                         task->tk_status = -EIO;
1416                         return;
1417                 }
1418                 /* Was this an NFSv2 write or an NFSv3 stable write? */
1419                 if (resp->verf->committed != NFS_UNSTABLE) {
1420                         /* Resend from where the server left off */
1421                         data->mds_offset += resp->count;
1422                         argp->offset += resp->count;
1423                         argp->pgbase += resp->count;
1424                         argp->count -= resp->count;
1425                 } else {
1426                         /* Resend as a stable write in order to avoid
1427                          * headaches in the case of a server crash.
1428                          */
1429                         argp->stable = NFS_FILE_SYNC;
1430                 }
1431                 rpc_restart_call_prepare(task);
1432         }
1433 }
1434
1435
1436 #if IS_ENABLED(CONFIG_NFS_V3) || IS_ENABLED(CONFIG_NFS_V4)
1437 static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
1438 {
1439         int ret;
1440
1441         if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
1442                 return 1;
1443         if (!may_wait)
1444                 return 0;
1445         ret = out_of_line_wait_on_bit_lock(&nfsi->flags,
1446                                 NFS_INO_COMMIT,
1447                                 nfs_wait_bit_killable,
1448                                 TASK_KILLABLE);
1449         return (ret < 0) ? ret : 1;
1450 }
1451
1452 static void nfs_commit_clear_lock(struct nfs_inode *nfsi)
1453 {
1454         clear_bit(NFS_INO_COMMIT, &nfsi->flags);
1455         smp_mb__after_clear_bit();
1456         wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
1457 }
1458
1459 void nfs_commitdata_release(struct nfs_commit_data *data)
1460 {
1461         put_nfs_open_context(data->context);
1462         nfs_commit_free(data);
1463 }
1464 EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1465
1466 int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1467                         const struct rpc_call_ops *call_ops,
1468                         int how, int flags)
1469 {
1470         struct rpc_task *task;
1471         int priority = flush_task_priority(how);
1472         struct rpc_message msg = {
1473                 .rpc_argp = &data->args,
1474                 .rpc_resp = &data->res,
1475                 .rpc_cred = data->cred,
1476         };
1477         struct rpc_task_setup task_setup_data = {
1478                 .task = &data->task,
1479                 .rpc_client = clnt,
1480                 .rpc_message = &msg,
1481                 .callback_ops = call_ops,
1482                 .callback_data = data,
1483                 .workqueue = nfsiod_workqueue,
1484                 .flags = RPC_TASK_ASYNC | flags,
1485                 .priority = priority,
1486         };
1487         /* Set up the initial task struct.  */
1488         NFS_PROTO(data->inode)->commit_setup(data, &msg);
1489
1490         dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1491
1492         nfs4_state_protect(NFS_SERVER(data->inode)->nfs_client,
1493                 NFS_SP4_MACH_CRED_COMMIT, &task_setup_data.rpc_client, &msg);
1494
1495         task = rpc_run_task(&task_setup_data);
1496         if (IS_ERR(task))
1497                 return PTR_ERR(task);
1498         if (how & FLUSH_SYNC)
1499                 rpc_wait_for_completion_task(task);
1500         rpc_put_task(task);
1501         return 0;
1502 }
1503 EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1504
1505 /*
1506  * Set up the argument/result storage required for the RPC call.
1507  */
1508 void nfs_init_commit(struct nfs_commit_data *data,
1509                      struct list_head *head,
1510                      struct pnfs_layout_segment *lseg,
1511                      struct nfs_commit_info *cinfo)
1512 {
1513         struct nfs_page *first = nfs_list_entry(head->next);
1514         struct inode *inode = first->wb_context->dentry->d_inode;
1515
1516         /* Set up the RPC argument and reply structs
1517          * NB: take care not to mess about with data->commit et al. */
1518
1519         list_splice_init(head, &data->pages);
1520
1521         data->inode       = inode;
1522         data->cred        = first->wb_context->cred;
1523         data->lseg        = lseg; /* reference transferred */
1524         data->mds_ops     = &nfs_commit_ops;
1525         data->completion_ops = cinfo->completion_ops;
1526         data->dreq        = cinfo->dreq;
1527
1528         data->args.fh     = NFS_FH(data->inode);
1529         /* Note: we always request a commit of the entire inode */
1530         data->args.offset = 0;
1531         data->args.count  = 0;
1532         data->context     = get_nfs_open_context(first->wb_context);
1533         data->res.fattr   = &data->fattr;
1534         data->res.verf    = &data->verf;
1535         nfs_fattr_init(&data->fattr);
1536 }
1537 EXPORT_SYMBOL_GPL(nfs_init_commit);
1538
1539 void nfs_retry_commit(struct list_head *page_list,
1540                       struct pnfs_layout_segment *lseg,
1541                       struct nfs_commit_info *cinfo)
1542 {
1543         struct nfs_page *req;
1544
1545         while (!list_empty(page_list)) {
1546                 req = nfs_list_entry(page_list->next);
1547                 nfs_list_remove_request(req);
1548                 nfs_mark_request_commit(req, lseg, cinfo);
1549                 if (!cinfo->dreq) {
1550                         dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1551                         dec_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info,
1552                                      BDI_RECLAIMABLE);
1553                 }
1554                 nfs_unlock_and_release_request(req);
1555         }
1556 }
1557 EXPORT_SYMBOL_GPL(nfs_retry_commit);
1558
1559 /*
1560  * Commit dirty pages
1561  */
1562 static int
1563 nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1564                 struct nfs_commit_info *cinfo)
1565 {
1566         struct nfs_commit_data  *data;
1567
1568         data = nfs_commitdata_alloc();
1569
1570         if (!data)
1571                 goto out_bad;
1572
1573         /* Set up the argument struct */
1574         nfs_init_commit(data, head, NULL, cinfo);
1575         atomic_inc(&cinfo->mds->rpcs_out);
1576         return nfs_initiate_commit(NFS_CLIENT(inode), data, data->mds_ops,
1577                                    how, 0);
1578  out_bad:
1579         nfs_retry_commit(head, NULL, cinfo);
1580         cinfo->completion_ops->error_cleanup(NFS_I(inode));
1581         return -ENOMEM;
1582 }
1583
1584 /*
1585  * COMMIT call returned
1586  */
1587 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1588 {
1589         struct nfs_commit_data  *data = calldata;
1590
1591         dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1592                                 task->tk_pid, task->tk_status);
1593
1594         /* Call the NFS version-specific code */
1595         NFS_PROTO(data->inode)->commit_done(task, data);
1596 }
1597
1598 static void nfs_commit_release_pages(struct nfs_commit_data *data)
1599 {
1600         struct nfs_page *req;
1601         int status = data->task.tk_status;
1602         struct nfs_commit_info cinfo;
1603
1604         while (!list_empty(&data->pages)) {
1605                 req = nfs_list_entry(data->pages.next);
1606                 nfs_list_remove_request(req);
1607                 nfs_clear_page_commit(req->wb_page);
1608
1609                 dprintk("NFS:       commit (%s/%lld %d@%lld)",
1610                         req->wb_context->dentry->d_sb->s_id,
1611                         (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1612                         req->wb_bytes,
1613                         (long long)req_offset(req));
1614                 if (status < 0) {
1615                         nfs_context_set_write_error(req->wb_context, status);
1616                         nfs_inode_remove_request(req);
1617                         dprintk(", error = %d\n", status);
1618                         goto next;
1619                 }
1620
1621                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1622                  * returned by the server against all stored verfs. */
1623                 if (!memcmp(&req->wb_verf, &data->verf.verifier, sizeof(req->wb_verf))) {
1624                         /* We have a match */
1625                         nfs_inode_remove_request(req);
1626                         dprintk(" OK\n");
1627                         goto next;
1628                 }
1629                 /* We have a mismatch. Write the page again */
1630                 dprintk(" mismatch\n");
1631                 nfs_mark_request_dirty(req);
1632                 set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags);
1633         next:
1634                 nfs_unlock_and_release_request(req);
1635         }
1636         nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1637         if (atomic_dec_and_test(&cinfo.mds->rpcs_out))
1638                 nfs_commit_clear_lock(NFS_I(data->inode));
1639 }
1640
1641 static void nfs_commit_release(void *calldata)
1642 {
1643         struct nfs_commit_data *data = calldata;
1644
1645         data->completion_ops->completion(data);
1646         nfs_commitdata_release(calldata);
1647 }
1648
1649 static const struct rpc_call_ops nfs_commit_ops = {
1650         .rpc_call_prepare = nfs_commit_prepare,
1651         .rpc_call_done = nfs_commit_done,
1652         .rpc_release = nfs_commit_release,
1653 };
1654
1655 static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1656         .completion = nfs_commit_release_pages,
1657         .error_cleanup = nfs_commit_clear_lock,
1658 };
1659
1660 int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1661                             int how, struct nfs_commit_info *cinfo)
1662 {
1663         int status;
1664
1665         status = pnfs_commit_list(inode, head, how, cinfo);
1666         if (status == PNFS_NOT_ATTEMPTED)
1667                 status = nfs_commit_list(inode, head, how, cinfo);
1668         return status;
1669 }
1670
1671 int nfs_commit_inode(struct inode *inode, int how)
1672 {
1673         LIST_HEAD(head);
1674         struct nfs_commit_info cinfo;
1675         int may_wait = how & FLUSH_SYNC;
1676         int res;
1677
1678         res = nfs_commit_set_lock(NFS_I(inode), may_wait);
1679         if (res <= 0)
1680                 goto out_mark_dirty;
1681         nfs_init_cinfo_from_inode(&cinfo, inode);
1682         res = nfs_scan_commit(inode, &head, &cinfo);
1683         if (res) {
1684                 int error;
1685
1686                 error = nfs_generic_commit_list(inode, &head, how, &cinfo);
1687                 if (error < 0)
1688                         return error;
1689                 if (!may_wait)
1690                         goto out_mark_dirty;
1691                 error = wait_on_bit(&NFS_I(inode)->flags,
1692                                 NFS_INO_COMMIT,
1693                                 nfs_wait_bit_killable,
1694                                 TASK_KILLABLE);
1695                 if (error < 0)
1696                         return error;
1697         } else
1698                 nfs_commit_clear_lock(NFS_I(inode));
1699         return res;
1700         /* Note: If we exit without ensuring that the commit is complete,
1701          * we must mark the inode as dirty. Otherwise, future calls to
1702          * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
1703          * that the data is on the disk.
1704          */
1705 out_mark_dirty:
1706         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1707         return res;
1708 }
1709
1710 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1711 {
1712         struct nfs_inode *nfsi = NFS_I(inode);
1713         int flags = FLUSH_SYNC;
1714         int ret = 0;
1715
1716         /* no commits means nothing needs to be done */
1717         if (!nfsi->commit_info.ncommit)
1718                 return ret;
1719
1720         if (wbc->sync_mode == WB_SYNC_NONE) {
1721                 /* Don't commit yet if this is a non-blocking flush and there
1722                  * are a lot of outstanding writes for this mapping.
1723                  */
1724                 if (nfsi->commit_info.ncommit <= (nfsi->npages >> 1))
1725                         goto out_mark_dirty;
1726
1727                 /* don't wait for the COMMIT response */
1728                 flags = 0;
1729         }
1730
1731         ret = nfs_commit_inode(inode, flags);
1732         if (ret >= 0) {
1733                 if (wbc->sync_mode == WB_SYNC_NONE) {
1734                         if (ret < wbc->nr_to_write)
1735                                 wbc->nr_to_write -= ret;
1736                         else
1737                                 wbc->nr_to_write = 0;
1738                 }
1739                 return 0;
1740         }
1741 out_mark_dirty:
1742         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1743         return ret;
1744 }
1745 #else
1746 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1747 {
1748         return 0;
1749 }
1750 #endif
1751
1752 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1753 {
1754         return nfs_commit_unstable_pages(inode, wbc);
1755 }
1756 EXPORT_SYMBOL_GPL(nfs_write_inode);
1757
1758 /*
1759  * flush the inode to disk.
1760  */
1761 int nfs_wb_all(struct inode *inode)
1762 {
1763         struct writeback_control wbc = {
1764                 .sync_mode = WB_SYNC_ALL,
1765                 .nr_to_write = LONG_MAX,
1766                 .range_start = 0,
1767                 .range_end = LLONG_MAX,
1768         };
1769         int ret;
1770
1771         trace_nfs_writeback_inode_enter(inode);
1772
1773         ret = sync_inode(inode, &wbc);
1774
1775         trace_nfs_writeback_inode_exit(inode, ret);
1776         return ret;
1777 }
1778 EXPORT_SYMBOL_GPL(nfs_wb_all);
1779
1780 int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1781 {
1782         struct nfs_page *req;
1783         int ret = 0;
1784
1785         for (;;) {
1786                 wait_on_page_writeback(page);
1787                 req = nfs_page_find_request(page);
1788                 if (req == NULL)
1789                         break;
1790                 if (nfs_lock_request(req)) {
1791                         nfs_clear_request_commit(req);
1792                         nfs_inode_remove_request(req);
1793                         /*
1794                          * In case nfs_inode_remove_request has marked the
1795                          * page as being dirty
1796                          */
1797                         cancel_dirty_page(page, PAGE_CACHE_SIZE);
1798                         nfs_unlock_and_release_request(req);
1799                         break;
1800                 }
1801                 ret = nfs_wait_on_request(req);
1802                 nfs_release_request(req);
1803                 if (ret < 0)
1804                         break;
1805         }
1806         return ret;
1807 }
1808
1809 /*
1810  * Write back all requests on one page - we do this before reading it.
1811  */
1812 int nfs_wb_page(struct inode *inode, struct page *page)
1813 {
1814         loff_t range_start = page_file_offset(page);
1815         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1816         struct writeback_control wbc = {
1817                 .sync_mode = WB_SYNC_ALL,
1818                 .nr_to_write = 0,
1819                 .range_start = range_start,
1820                 .range_end = range_end,
1821         };
1822         int ret;
1823
1824         trace_nfs_writeback_page_enter(inode);
1825
1826         for (;;) {
1827                 wait_on_page_writeback(page);
1828                 if (clear_page_dirty_for_io(page)) {
1829                         ret = nfs_writepage_locked(page, &wbc);
1830                         if (ret < 0)
1831                                 goto out_error;
1832                         continue;
1833                 }
1834                 ret = 0;
1835                 if (!PagePrivate(page))
1836                         break;
1837                 ret = nfs_commit_inode(inode, FLUSH_SYNC);
1838                 if (ret < 0)
1839                         goto out_error;
1840         }
1841 out_error:
1842         trace_nfs_writeback_page_exit(inode, ret);
1843         return ret;
1844 }
1845
1846 #ifdef CONFIG_MIGRATION
1847 int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
1848                 struct page *page, enum migrate_mode mode)
1849 {
1850         /*
1851          * If PagePrivate is set, then the page is currently associated with
1852          * an in-progress read or write request. Don't try to migrate it.
1853          *
1854          * FIXME: we could do this in principle, but we'll need a way to ensure
1855          *        that we can safely release the inode reference while holding
1856          *        the page lock.
1857          */
1858         if (PagePrivate(page))
1859                 return -EBUSY;
1860
1861         if (!nfs_fscache_release_page(page, GFP_KERNEL))
1862                 return -EBUSY;
1863
1864         return migrate_page(mapping, newpage, page, mode);
1865 }
1866 #endif
1867
1868 int __init nfs_init_writepagecache(void)
1869 {
1870         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1871                                              sizeof(struct nfs_write_header),
1872                                              0, SLAB_HWCACHE_ALIGN,
1873                                              NULL);
1874         if (nfs_wdata_cachep == NULL)
1875                 return -ENOMEM;
1876
1877         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1878                                                      nfs_wdata_cachep);
1879         if (nfs_wdata_mempool == NULL)
1880                 goto out_destroy_write_cache;
1881
1882         nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
1883                                              sizeof(struct nfs_commit_data),
1884                                              0, SLAB_HWCACHE_ALIGN,
1885                                              NULL);
1886         if (nfs_cdata_cachep == NULL)
1887                 goto out_destroy_write_mempool;
1888
1889         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1890                                                       nfs_cdata_cachep);
1891         if (nfs_commit_mempool == NULL)
1892                 goto out_destroy_commit_cache;
1893
1894         /*
1895          * NFS congestion size, scale with available memory.
1896          *
1897          *  64MB:    8192k
1898          * 128MB:   11585k
1899          * 256MB:   16384k
1900          * 512MB:   23170k
1901          *   1GB:   32768k
1902          *   2GB:   46340k
1903          *   4GB:   65536k
1904          *   8GB:   92681k
1905          *  16GB:  131072k
1906          *
1907          * This allows larger machines to have larger/more transfers.
1908          * Limit the default to 256M
1909          */
1910         nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1911         if (nfs_congestion_kb > 256*1024)
1912                 nfs_congestion_kb = 256*1024;
1913
1914         return 0;
1915
1916 out_destroy_commit_cache:
1917         kmem_cache_destroy(nfs_cdata_cachep);
1918 out_destroy_write_mempool:
1919         mempool_destroy(nfs_wdata_mempool);
1920 out_destroy_write_cache:
1921         kmem_cache_destroy(nfs_wdata_cachep);
1922         return -ENOMEM;
1923 }
1924
1925 void nfs_destroy_writepagecache(void)
1926 {
1927         mempool_destroy(nfs_commit_mempool);
1928         kmem_cache_destroy(nfs_cdata_cachep);
1929         mempool_destroy(nfs_wdata_mempool);
1930         kmem_cache_destroy(nfs_wdata_cachep);
1931 }
1932