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