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
  24 #include <asm/uaccess.h>
  25
  26 #include "delegation.h"
  27 #include "internal.h"
  28 #include "iostat.h"
  29 #include "nfs4_fs.h"
  30 #include "fscache.h"
  31
  32 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  33
  34 #define MIN_POOL_WRITE          (32)
  35 #define MIN_POOL_COMMIT         (4)
  36
  37 /*
  38  * Local function declarations
  39  */
  40 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *desc,
  41                                   struct inode *inode, int ioflags);
  42 static void nfs_redirty_request(struct nfs_page *req);
  43 static const struct rpc_call_ops nfs_write_partial_ops;
  44 static const struct rpc_call_ops nfs_write_full_ops;
  45 static const struct rpc_call_ops nfs_commit_ops;
  46
  47 static struct kmem_cache *nfs_wdata_cachep;
  48 static mempool_t *nfs_wdata_mempool;
  49 static mempool_t *nfs_commit_mempool;
  50
  51 struct nfs_write_data *nfs_commitdata_alloc(void)
  52 {
  53         struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
  54
  55         if (p) {
  56                 memset(p, 0, sizeof(*p));
  57                 INIT_LIST_HEAD(&p->pages);
  58         }
  59         return p;
  60 }
  61
  62 void nfs_commit_free(struct nfs_write_data *p)
  63 {
  64         if (p && (p->pagevec != &p->page_array[0]))
  65                 kfree(p->pagevec);
  66         mempool_free(p, nfs_commit_mempool);
  67 }
  68
  69 struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
  70 {
  71         struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
  72
  73         if (p) {
  74                 memset(p, 0, sizeof(*p));
  75                 INIT_LIST_HEAD(&p->pages);
  76                 p->npages = pagecount;
  77                 if (pagecount <= ARRAY_SIZE(p->page_array))
  78                         p->pagevec = p->page_array;
  79                 else {
  80                         p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
  81                         if (!p->pagevec) {
  82                                 mempool_free(p, nfs_wdata_mempool);
  83                                 p = NULL;
  84                         }
  85                 }
  86         }
  87         return p;
  88 }
  89
  90 void nfs_writedata_free(struct nfs_write_data *p)
  91 {
  92         if (p && (p->pagevec != &p->page_array[0]))
  93                 kfree(p->pagevec);
  94         mempool_free(p, nfs_wdata_mempool);
  95 }
  96
  97 static void nfs_writedata_release(struct nfs_write_data *wdata)
  98 {
  99         put_nfs_open_context(wdata->args.context);
 100         nfs_writedata_free(wdata);
 101 }
 102
 103 static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
 104 {
 105         ctx->error = error;
 106         smp_wmb();
 107         set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 108 }
 109
 110 static struct nfs_page *nfs_page_find_request_locked(struct page *page)
 111 {
 112         struct nfs_page *req = NULL;
 113
 114         if (PagePrivate(page)) {
 115                 req = (struct nfs_page *)page_private(page);
 116                 if (req != NULL)
 117                         kref_get(&req->wb_kref);
 118         }
 119         return req;
 120 }
 121
 122 static struct nfs_page *nfs_page_find_request(struct page *page)
 123 {
 124         struct inode *inode = page->mapping->host;
 125         struct nfs_page *req = NULL;
 126
 127         spin_lock(&inode->i_lock);
 128         req = nfs_page_find_request_locked(page);
 129         spin_unlock(&inode->i_lock);
 130         return req;
 131 }
 132
 133 /* Adjust the file length if we're writing beyond the end */
 134 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 135 {
 136         struct inode *inode = page->mapping->host;
 137         loff_t end, i_size;
 138         pgoff_t end_index;
 139
 140         spin_lock(&inode->i_lock);
 141         i_size = i_size_read(inode);
 142         end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 143         if (i_size > 0 && page->index < end_index)
 144                 goto out;
 145         end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
 146         if (i_size >= end)
 147                 goto out;
 148         i_size_write(inode, end);
 149         nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 150 out:
 151         spin_unlock(&inode->i_lock);
 152 }
 153
 154 /* A writeback failed: mark the page as bad, and invalidate the page cache */
 155 static void nfs_set_pageerror(struct page *page)
 156 {
 157         SetPageError(page);
 158         nfs_zap_mapping(page->mapping->host, page->mapping);
 159 }
 160
 161 /* We can set the PG_uptodate flag if we see that a write request
 162  * covers the full page.
 163  */
 164 static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
 165 {
 166         if (PageUptodate(page))
 167                 return;
 168         if (base != 0)
 169                 return;
 170         if (count != nfs_page_length(page))
 171                 return;
 172         SetPageUptodate(page);
 173 }
 174
 175 static int wb_priority(struct writeback_control *wbc)
 176 {
 177         if (wbc->for_reclaim)
 178                 return FLUSH_HIGHPRI | FLUSH_STABLE;
 179         if (wbc->for_kupdate || wbc->for_background)
 180                 return FLUSH_LOWPRI;
 181         return 0;
 182 }
 183
 184 /*
 185  * NFS congestion control
 186  */
 187
 188 int nfs_congestion_kb;
 189
 190 #define NFS_CONGESTION_ON_THRESH        (nfs_congestion_kb >> (PAGE_SHIFT-10))
 191 #define NFS_CONGESTION_OFF_THRESH       \
 192         (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 193
 194 static int nfs_set_page_writeback(struct page *page)
 195 {
 196         int ret = test_set_page_writeback(page);
 197
 198         if (!ret) {
 199                 struct inode *inode = page->mapping->host;
 200                 struct nfs_server *nfss = NFS_SERVER(inode);
 201
 202                 page_cache_get(page);
 203                 if (atomic_long_inc_return(&nfss->writeback) >
 204                                 NFS_CONGESTION_ON_THRESH) {
 205                         set_bdi_congested(&nfss->backing_dev_info,
 206                                                 BLK_RW_ASYNC);
 207                 }
 208         }
 209         return ret;
 210 }
 211
 212 static void nfs_end_page_writeback(struct page *page)
 213 {
 214         struct inode *inode = page->mapping->host;
 215         struct nfs_server *nfss = NFS_SERVER(inode);
 216
 217         end_page_writeback(page);
 218         page_cache_release(page);
 219         if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 220                 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
 221 }
 222
 223 static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
 224 {
 225         struct inode *inode = page->mapping->host;
 226         struct nfs_page *req;
 227         int ret;
 228
 229         spin_lock(&inode->i_lock);
 230         for (;;) {
 231                 req = nfs_page_find_request_locked(page);
 232                 if (req == NULL)
 233                         break;
 234                 if (nfs_set_page_tag_locked(req))
 235                         break;
 236                 /* Note: If we hold the page lock, as is the case in nfs_writepage,
 237                  *       then the call to nfs_set_page_tag_locked() will always
 238                  *       succeed provided that someone hasn't already marked the
 239                  *       request as dirty (in which case we don't care).
 240                  */
 241                 spin_unlock(&inode->i_lock);
 242                 if (!nonblock)
 243                         ret = nfs_wait_on_request(req);
 244                 else
 245                         ret = -EAGAIN;
 246                 nfs_release_request(req);
 247                 if (ret != 0)
 248                         return ERR_PTR(ret);
 249                 spin_lock(&inode->i_lock);
 250         }
 251         spin_unlock(&inode->i_lock);
 252         return req;
 253 }
 254
 255 /*
 256  * Find an associated nfs write request, and prepare to flush it out
 257  * May return an error if the user signalled nfs_wait_on_request().
 258  */
 259 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 260                                 struct page *page, bool nonblock)
 261 {
 262         struct nfs_page *req;
 263         int ret = 0;
 264
 265         req = nfs_find_and_lock_request(page, nonblock);
 266         if (!req)
 267                 goto out;
 268         ret = PTR_ERR(req);
 269         if (IS_ERR(req))
 270                 goto out;
 271
 272         ret = nfs_set_page_writeback(page);
 273         BUG_ON(ret != 0);
 274         BUG_ON(test_bit(PG_CLEAN, &req->wb_flags));
 275
 276         if (!nfs_pageio_add_request(pgio, req)) {
 277                 nfs_redirty_request(req);
 278                 ret = pgio->pg_error;
 279         }
 280 out:
 281         return ret;
 282 }
 283
 284 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
 285 {
 286         struct inode *inode = page->mapping->host;
 287         int ret;
 288
 289         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 290         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 291
 292         nfs_pageio_cond_complete(pgio, page->index);
 293         ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
 294         if (ret == -EAGAIN) {
 295                 redirty_page_for_writepage(wbc, page);
 296                 ret = 0;
 297         }
 298         return ret;
 299 }
 300
 301 /*
 302  * Write an mmapped page to the server.
 303  */
 304 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 305 {
 306         struct nfs_pageio_descriptor pgio;
 307         int err;
 308
 309         nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc));
 310         err = nfs_do_writepage(page, wbc, &pgio);
 311         nfs_pageio_complete(&pgio);
 312         if (err < 0)
 313                 return err;
 314         if (pgio.pg_error < 0)
 315                 return pgio.pg_error;
 316         return 0;
 317 }
 318
 319 int nfs_writepage(struct page *page, struct writeback_control *wbc)
 320 {
 321         int ret;
 322
 323         ret = nfs_writepage_locked(page, wbc);
 324         unlock_page(page);
 325         return ret;
 326 }
 327
 328 static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
 329 {
 330         int ret;
 331
 332         ret = nfs_do_writepage(page, wbc, data);
 333         unlock_page(page);
 334         return ret;
 335 }
 336
 337 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 338 {
 339         struct inode *inode = mapping->host;
 340         unsigned long *bitlock = &NFS_I(inode)->flags;
 341         struct nfs_pageio_descriptor pgio;
 342         int err;
 343
 344         /* Stop dirtying of new pages while we sync */
 345         err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
 346                         nfs_wait_bit_killable, TASK_KILLABLE);
 347         if (err)
 348                 goto out_err;
 349
 350         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 351
 352         nfs_pageio_init_write(&pgio, inode, wb_priority(wbc));
 353         err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
 354         nfs_pageio_complete(&pgio);
 355
 356         clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
 357         smp_mb__after_clear_bit();
 358         wake_up_bit(bitlock, NFS_INO_FLUSHING);
 359
 360         if (err < 0)
 361                 goto out_err;
 362         err = pgio.pg_error;
 363         if (err < 0)
 364                 goto out_err;
 365         return 0;
 366 out_err:
 367         return err;
 368 }
 369
 370 /*
 371  * Insert a write request into an inode
 372  */
 373 static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 374 {
 375         struct nfs_inode *nfsi = NFS_I(inode);
 376         int error;
 377
 378         error = radix_tree_preload(GFP_NOFS);
 379         if (error != 0)
 380                 goto out;
 381
 382         /* Lock the request! */
 383         nfs_lock_request_dontget(req);
 384
 385         spin_lock(&inode->i_lock);
 386         error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
 387         BUG_ON(error);
 388         if (!nfsi->npages) {
 389                 igrab(inode);
 390                 if (nfs_have_delegation(inode, FMODE_WRITE))
 391                         nfsi->change_attr++;
 392         }
 393         SetPagePrivate(req->wb_page);
 394         set_page_private(req->wb_page, (unsigned long)req);
 395         nfsi->npages++;
 396         kref_get(&req->wb_kref);
 397         radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
 398                                 NFS_PAGE_TAG_LOCKED);
 399         spin_unlock(&inode->i_lock);
 400         radix_tree_preload_end();
 401 out:
 402         return error;
 403 }
 404
 405 /*
 406  * Remove a write request from an inode
 407  */
 408 static void nfs_inode_remove_request(struct nfs_page *req)
 409 {
 410         struct inode *inode = req->wb_context->path.dentry->d_inode;
 411         struct nfs_inode *nfsi = NFS_I(inode);
 412
 413         BUG_ON (!NFS_WBACK_BUSY(req));
 414
 415         spin_lock(&inode->i_lock);
 416         set_page_private(req->wb_page, 0);
 417         ClearPagePrivate(req->wb_page);
 418         radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
 419         nfsi->npages--;
 420         if (!nfsi->npages) {
 421                 spin_unlock(&inode->i_lock);
 422                 iput(inode);
 423         } else
 424                 spin_unlock(&inode->i_lock);
 425         nfs_clear_request(req);
 426         nfs_release_request(req);
 427 }
 428
 429 static void
 430 nfs_mark_request_dirty(struct nfs_page *req)
 431 {
 432         __set_page_dirty_nobuffers(req->wb_page);
 433         __mark_inode_dirty(req->wb_page->mapping->host, I_DIRTY_DATASYNC);
 434 }
 435
 436 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 437 /*
 438  * Add a request to the inode's commit list.
 439  */
 440 static void
 441 nfs_mark_request_commit(struct nfs_page *req)
 442 {
 443         struct inode *inode = req->wb_context->path.dentry->d_inode;
 444         struct nfs_inode *nfsi = NFS_I(inode);
 445
 446         spin_lock(&inode->i_lock);
 447         set_bit(PG_CLEAN, &(req)->wb_flags);
 448         radix_tree_tag_set(&nfsi->nfs_page_tree,
 449                         req->wb_index,
 450                         NFS_PAGE_TAG_COMMIT);
 451         nfsi->ncommit++;
 452         spin_unlock(&inode->i_lock);
 453         inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 454         inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 455         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 456 }
 457
 458 static int
 459 nfs_clear_request_commit(struct nfs_page *req)
 460 {
 461         struct page *page = req->wb_page;
 462
 463         if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
 464                 dec_zone_page_state(page, NR_UNSTABLE_NFS);
 465                 dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 466                 return 1;
 467         }
 468         return 0;
 469 }
 470
 471 static inline
 472 int nfs_write_need_commit(struct nfs_write_data *data)
 473 {
 474         return data->verf.committed != NFS_FILE_SYNC;
 475 }
 476
 477 static inline
 478 int nfs_reschedule_unstable_write(struct nfs_page *req)
 479 {
 480         if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {
 481                 nfs_mark_request_commit(req);
 482                 return 1;
 483         }
 484         if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
 485                 nfs_mark_request_dirty(req);
 486                 return 1;
 487         }
 488         return 0;
 489 }
 490 #else
 491 static inline void
 492 nfs_mark_request_commit(struct nfs_page *req)
 493 {
 494 }
 495
 496 static inline int
 497 nfs_clear_request_commit(struct nfs_page *req)
 498 {
 499         return 0;
 500 }
 501
 502 static inline
 503 int nfs_write_need_commit(struct nfs_write_data *data)
 504 {
 505         return 0;
 506 }
 507
 508 static inline
 509 int nfs_reschedule_unstable_write(struct nfs_page *req)
 510 {
 511         return 0;
 512 }
 513 #endif
 514
 515 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 516 static int
 517 nfs_need_commit(struct nfs_inode *nfsi)
 518 {
 519         return radix_tree_tagged(&nfsi->nfs_page_tree, NFS_PAGE_TAG_COMMIT);
 520 }
 521
 522 /*
 523  * nfs_scan_commit - Scan an inode for commit requests
 524  * @inode: NFS inode to scan
 525  * @dst: destination list
 526  * @idx_start: lower bound of page->index to scan.
 527  * @npages: idx_start + npages sets the upper bound to scan.
 528  *
 529  * Moves requests from the inode's 'commit' request list.
 530  * The requests are *not* checked to ensure that they form a contiguous set.
 531  */
 532 static int
 533 nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 534 {
 535         struct nfs_inode *nfsi = NFS_I(inode);
 536         int ret;
 537
 538         if (!nfs_need_commit(nfsi))
 539                 return 0;
 540
 541         ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
 542         if (ret > 0)
 543                 nfsi->ncommit -= ret;
 544         if (nfs_need_commit(NFS_I(inode)))
 545                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 546         return ret;
 547 }
 548 #else
 549 static inline int nfs_need_commit(struct nfs_inode *nfsi)
 550 {
 551         return 0;
 552 }
 553
 554 static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 555 {
 556         return 0;
 557 }
 558 #endif
 559
 560 /*
 561  * Search for an existing write request, and attempt to update
 562  * it to reflect a new dirty region on a given page.
 563  *
 564  * If the attempt fails, then the existing request is flushed out
 565  * to disk.
 566  */
 567 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
 568                 struct page *page,
 569                 unsigned int offset,
 570                 unsigned int bytes)
 571 {
 572         struct nfs_page *req;
 573         unsigned int rqend;
 574         unsigned int end;
 575         int error;
 576
 577         if (!PagePrivate(page))
 578                 return NULL;
 579
 580         end = offset + bytes;
 581         spin_lock(&inode->i_lock);
 582
 583         for (;;) {
 584                 req = nfs_page_find_request_locked(page);
 585                 if (req == NULL)
 586                         goto out_unlock;
 587
 588                 rqend = req->wb_offset + req->wb_bytes;
 589                 /*
 590                  * Tell the caller to flush out the request if
 591                  * the offsets are non-contiguous.
 592                  * Note: nfs_flush_incompatible() will already
 593                  * have flushed out requests having wrong owners.
 594                  */
 595                 if (offset > rqend
 596                     || end < req->wb_offset)
 597                         goto out_flushme;
 598
 599                 if (nfs_set_page_tag_locked(req))
 600                         break;
 601
 602                 /* The request is locked, so wait and then retry */
 603                 spin_unlock(&inode->i_lock);
 604                 error = nfs_wait_on_request(req);
 605                 nfs_release_request(req);
 606                 if (error != 0)
 607                         goto out_err;
 608                 spin_lock(&inode->i_lock);
 609         }
 610
 611         if (nfs_clear_request_commit(req) &&
 612                         radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
 613                                 req->wb_index, NFS_PAGE_TAG_COMMIT) != NULL)
 614                 NFS_I(inode)->ncommit--;
 615
 616         /* Okay, the request matches. Update the region */
 617         if (offset < req->wb_offset) {
 618                 req->wb_offset = offset;
 619                 req->wb_pgbase = offset;
 620         }
 621         if (end > rqend)
 622                 req->wb_bytes = end - req->wb_offset;
 623         else
 624                 req->wb_bytes = rqend - req->wb_offset;
 625 out_unlock:
 626         spin_unlock(&inode->i_lock);
 627         return req;
 628 out_flushme:
 629         spin_unlock(&inode->i_lock);
 630         nfs_release_request(req);
 631         error = nfs_wb_page(inode, page);
 632 out_err:
 633         return ERR_PTR(error);
 634 }
 635
 636 /*
 637  * Try to update an existing write request, or create one if there is none.
 638  *
 639  * Note: Should always be called with the Page Lock held to prevent races
 640  * if we have to add a new request. Also assumes that the caller has
 641  * already called nfs_flush_incompatible() if necessary.
 642  */
 643 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
 644                 struct page *page, unsigned int offset, unsigned int bytes)
 645 {
 646         struct inode *inode = page->mapping->host;
 647         struct nfs_page *req;
 648         int error;
 649
 650         req = nfs_try_to_update_request(inode, page, offset, bytes);
 651         if (req != NULL)
 652                 goto out;
 653         req = nfs_create_request(ctx, inode, page, offset, bytes);
 654         if (IS_ERR(req))
 655                 goto out;
 656         error = nfs_inode_add_request(inode, req);
 657         if (error != 0) {
 658                 nfs_release_request(req);
 659                 req = ERR_PTR(error);
 660         }
 661 out:
 662         return req;
 663 }
 664
 665 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 666                 unsigned int offset, unsigned int count)
 667 {
 668         struct nfs_page *req;
 669
 670         req = nfs_setup_write_request(ctx, page, offset, count);
 671         if (IS_ERR(req))
 672                 return PTR_ERR(req);
 673         nfs_mark_request_dirty(req);
 674         /* Update file length */
 675         nfs_grow_file(page, offset, count);
 676         nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
 677         nfs_mark_request_dirty(req);
 678         nfs_clear_page_tag_locked(req);
 679         return 0;
 680 }
 681
 682 int nfs_flush_incompatible(struct file *file, struct page *page)
 683 {
 684         struct nfs_open_context *ctx = nfs_file_open_context(file);
 685         struct nfs_page *req;
 686         int do_flush, status;
 687         /*
 688          * Look for a request corresponding to this page. If there
 689          * is one, and it belongs to another file, we flush it out
 690          * before we try to copy anything into the page. Do this
 691          * due to the lack of an ACCESS-type call in NFSv2.
 692          * Also do the same if we find a request from an existing
 693          * dropped page.
 694          */
 695         do {
 696                 req = nfs_page_find_request(page);
 697                 if (req == NULL)
 698                         return 0;
 699                 do_flush = req->wb_page != page || req->wb_context != ctx ||
 700                         req->wb_lock_context->lockowner != current->files ||
 701                         req->wb_lock_context->pid != current->tgid;
 702                 nfs_release_request(req);
 703                 if (!do_flush)
 704                         return 0;
 705                 status = nfs_wb_page(page->mapping->host, page);
 706         } while (status == 0);
 707         return status;
 708 }
 709
 710 /*
 711  * If the page cache is marked as unsafe or invalid, then we can't rely on
 712  * the PageUptodate() flag. In this case, we will need to turn off
 713  * write optimisations that depend on the page contents being correct.
 714  */
 715 static int nfs_write_pageuptodate(struct page *page, struct inode *inode)
 716 {
 717         return PageUptodate(page) &&
 718                 !(NFS_I(inode)->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA));
 719 }
 720
 721 /*
 722  * Update and possibly write a cached page of an NFS file.
 723  *
 724  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
 725  * things with a page scheduled for an RPC call (e.g. invalidate it).
 726  */
 727 int nfs_updatepage(struct file *file, struct page *page,
 728                 unsigned int offset, unsigned int count)
 729 {
 730         struct nfs_open_context *ctx = nfs_file_open_context(file);
 731         struct inode    *inode = page->mapping->host;
 732         int             status = 0;
 733
 734         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 735
 736         dprintk("NFS:       nfs_updatepage(%s/%s %d@%lld)\n",
 737                 file->f_path.dentry->d_parent->d_name.name,
 738                 file->f_path.dentry->d_name.name, count,
 739                 (long long)(page_offset(page) + offset));
 740
 741         /* If we're not using byte range locks, and we know the page
 742          * is up to date, it may be more efficient to extend the write
 743          * to cover the entire page in order to avoid fragmentation
 744          * inefficiencies.
 745          */
 746         if (nfs_write_pageuptodate(page, inode) &&
 747                         inode->i_flock == NULL &&
 748                         !(file->f_flags & O_DSYNC)) {
 749                 count = max(count + offset, nfs_page_length(page));
 750                 offset = 0;
 751         }
 752
 753         status = nfs_writepage_setup(ctx, page, offset, count);
 754         if (status < 0)
 755                 nfs_set_pageerror(page);
 756
 757         dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
 758                         status, (long long)i_size_read(inode));
 759         return status;
 760 }
 761
 762 static void nfs_writepage_release(struct nfs_page *req)
 763 {
 764         struct page *page = req->wb_page;
 765
 766         if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req))
 767                 nfs_inode_remove_request(req);
 768         nfs_clear_page_tag_locked(req);
 769         nfs_end_page_writeback(page);
 770 }
 771
 772 static int flush_task_priority(int how)
 773 {
 774         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
 775                 case FLUSH_HIGHPRI:
 776                         return RPC_PRIORITY_HIGH;
 777                 case FLUSH_LOWPRI:
 778                         return RPC_PRIORITY_LOW;
 779         }
 780         return RPC_PRIORITY_NORMAL;
 781 }
 782
 783 /*
 784  * Set up the argument/result storage required for the RPC call.
 785  */
 786 static int nfs_write_rpcsetup(struct nfs_page *req,
 787                 struct nfs_write_data *data,
 788                 const struct rpc_call_ops *call_ops,
 789                 unsigned int count, unsigned int offset,
 790                 int how)
 791 {
 792         struct inode *inode = req->wb_context->path.dentry->d_inode;
 793         int priority = flush_task_priority(how);
 794         struct rpc_task *task;
 795         struct rpc_message msg = {
 796                 .rpc_argp = &data->args,
 797                 .rpc_resp = &data->res,
 798                 .rpc_cred = req->wb_context->cred,
 799         };
 800         struct rpc_task_setup task_setup_data = {
 801                 .rpc_client = NFS_CLIENT(inode),
 802                 .task = &data->task,
 803                 .rpc_message = &msg,
 804                 .callback_ops = call_ops,
 805                 .callback_data = data,
 806                 .workqueue = nfsiod_workqueue,
 807                 .flags = RPC_TASK_ASYNC,
 808                 .priority = priority,
 809         };
 810         int ret = 0;
 811
 812         /* Set up the RPC argument and reply structs
 813          * NB: take care not to mess about with data->commit et al. */
 814
 815         data->req = req;
 816         data->inode = inode = req->wb_context->path.dentry->d_inode;
 817         data->cred = msg.rpc_cred;
 818
 819         data->args.fh     = NFS_FH(inode);
 820         data->args.offset = req_offset(req) + offset;
 821         data->args.pgbase = req->wb_pgbase + offset;
 822         data->args.pages  = data->pagevec;
 823         data->args.count  = count;
 824         data->args.context = get_nfs_open_context(req->wb_context);
 825         data->args.lock_context = req->wb_lock_context;
 826         data->args.stable  = NFS_UNSTABLE;
 827         if (how & FLUSH_STABLE) {
 828                 data->args.stable = NFS_DATA_SYNC;
 829                 if (!nfs_need_commit(NFS_I(inode)))
 830                         data->args.stable = NFS_FILE_SYNC;
 831         }
 832
 833         data->res.fattr   = &data->fattr;
 834         data->res.count   = count;
 835         data->res.verf    = &data->verf;
 836         nfs_fattr_init(&data->fattr);
 837
 838         /* Set up the initial task struct.  */
 839         NFS_PROTO(inode)->write_setup(data, &msg);
 840
 841         dprintk("NFS: %5u initiated write call "
 842                 "(req %s/%lld, %u bytes @ offset %llu)\n",
 843                 data->task.tk_pid,
 844                 inode->i_sb->s_id,
 845                 (long long)NFS_FILEID(inode),
 846                 count,
 847                 (unsigned long long)data->args.offset);
 848
 849         task = rpc_run_task(&task_setup_data);
 850         if (IS_ERR(task)) {
 851                 ret = PTR_ERR(task);
 852                 goto out;
 853         }
 854         if (how & FLUSH_SYNC) {
 855                 ret = rpc_wait_for_completion_task(task);
 856                 if (ret == 0)
 857                         ret = task->tk_status;
 858         }
 859         rpc_put_task(task);
 860 out:
 861         return ret;
 862 }
 863
 864 /* If a nfs_flush_* function fails, it should remove reqs from @head and
 865  * call this on each, which will prepare them to be retried on next
 866  * writeback using standard nfs.
 867  */
 868 static void nfs_redirty_request(struct nfs_page *req)
 869 {
 870         struct page *page = req->wb_page;
 871
 872         nfs_mark_request_dirty(req);
 873         nfs_clear_page_tag_locked(req);
 874         nfs_end_page_writeback(page);
 875 }
 876
 877 /*
 878  * Generate multiple small requests to write out a single
 879  * contiguous dirty area on one page.
 880  */
 881 static int nfs_flush_multi(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int how)
 882 {
 883         struct nfs_page *req = nfs_list_entry(head->next);
 884         struct page *page = req->wb_page;
 885         struct nfs_write_data *data;
 886         size_t wsize = NFS_SERVER(inode)->wsize, nbytes;
 887         unsigned int offset;
 888         int requests = 0;
 889         int ret = 0;
 890         LIST_HEAD(list);
 891
 892         nfs_list_remove_request(req);
 893
 894         nbytes = count;
 895         do {
 896                 size_t len = min(nbytes, wsize);
 897
 898                 data = nfs_writedata_alloc(1);
 899                 if (!data)
 900                         goto out_bad;
 901                 list_add(&data->pages, &list);
 902                 requests++;
 903                 nbytes -= len;
 904         } while (nbytes != 0);
 905         atomic_set(&req->wb_complete, requests);
 906
 907         ClearPageError(page);
 908         offset = 0;
 909         nbytes = count;
 910         do {
 911                 int ret2;
 912
 913                 data = list_entry(list.next, struct nfs_write_data, pages);
 914                 list_del_init(&data->pages);
 915
 916                 data->pagevec[0] = page;
 917
 918                 if (nbytes < wsize)
 919                         wsize = nbytes;
 920                 ret2 = nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
 921                                    wsize, offset, how);
 922                 if (ret == 0)
 923                         ret = ret2;
 924                 offset += wsize;
 925                 nbytes -= wsize;
 926         } while (nbytes != 0);
 927
 928         return ret;
 929
 930 out_bad:
 931         while (!list_empty(&list)) {
 932                 data = list_entry(list.next, struct nfs_write_data, pages);
 933                 list_del(&data->pages);
 934                 nfs_writedata_release(data);
 935         }
 936         nfs_redirty_request(req);
 937         return -ENOMEM;
 938 }
 939
 940 /*
 941  * Create an RPC task for the given write request and kick it.
 942  * The page must have been locked by the caller.
 943  *
 944  * It may happen that the page we're passed is not marked dirty.
 945  * This is the case if nfs_updatepage detects a conflicting request
 946  * that has been written but not committed.
 947  */
 948 static int nfs_flush_one(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int how)
 949 {
 950         struct nfs_page         *req;
 951         struct page             **pages;
 952         struct nfs_write_data   *data;
 953
 954         data = nfs_writedata_alloc(npages);
 955         if (!data)
 956                 goto out_bad;
 957
 958         pages = data->pagevec;
 959         while (!list_empty(head)) {
 960                 req = nfs_list_entry(head->next);
 961                 nfs_list_remove_request(req);
 962                 nfs_list_add_request(req, &data->pages);
 963                 ClearPageError(req->wb_page);
 964                 *pages++ = req->wb_page;
 965         }
 966         req = nfs_list_entry(data->pages.next);
 967
 968         /* Set up the argument struct */
 969         return nfs_write_rpcsetup(req, data, &nfs_write_full_ops, count, 0, how);
 970  out_bad:
 971         while (!list_empty(head)) {
 972                 req = nfs_list_entry(head->next);
 973                 nfs_list_remove_request(req);
 974                 nfs_redirty_request(req);
 975         }
 976         return -ENOMEM;
 977 }
 978
 979 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
 980                                   struct inode *inode, int ioflags)
 981 {
 982         size_t wsize = NFS_SERVER(inode)->wsize;
 983
 984         if (wsize < PAGE_CACHE_SIZE)
 985                 nfs_pageio_init(pgio, inode, nfs_flush_multi, wsize, ioflags);
 986         else
 987                 nfs_pageio_init(pgio, inode, nfs_flush_one, wsize, ioflags);
 988 }
 989
 990 /*
 991  * Handle a write reply that flushed part of a page.
 992  */
 993 static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
 994 {
 995         struct nfs_write_data   *data = calldata;
 996
 997         dprintk("NFS: %5u write(%s/%lld %d@%lld)",
 998                 task->tk_pid,
 999                 data->req->wb_context->path.dentry->d_inode->i_sb->s_id,
1000                 (long long)
1001                   NFS_FILEID(data->req->wb_context->path.dentry->d_inode),
1002                 data->req->wb_bytes, (long long)req_offset(data->req));
1003
1004         nfs_writeback_done(task, data);
1005 }
1006
1007 static void nfs_writeback_release_partial(void *calldata)
1008 {
1009         struct nfs_write_data   *data = calldata;
1010         struct nfs_page         *req = data->req;
1011         struct page             *page = req->wb_page;
1012         int status = data->task.tk_status;
1013
1014         if (status < 0) {
1015                 nfs_set_pageerror(page);
1016                 nfs_context_set_write_error(req->wb_context, status);
1017                 dprintk(", error = %d\n", status);
1018                 goto out;
1019         }
1020
1021         if (nfs_write_need_commit(data)) {
1022                 struct inode *inode = page->mapping->host;
1023
1024                 spin_lock(&inode->i_lock);
1025                 if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
1026                         /* Do nothing we need to resend the writes */
1027                 } else if (!test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) {
1028                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1029                         dprintk(" defer commit\n");
1030                 } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
1031                         set_bit(PG_NEED_RESCHED, &req->wb_flags);
1032                         clear_bit(PG_NEED_COMMIT, &req->wb_flags);
1033                         dprintk(" server reboot detected\n");
1034                 }
1035                 spin_unlock(&inode->i_lock);
1036         } else
1037                 dprintk(" OK\n");
1038
1039 out:
1040         if (atomic_dec_and_test(&req->wb_complete))
1041                 nfs_writepage_release(req);
1042         nfs_writedata_release(calldata);
1043 }
1044
1045 #if defined(CONFIG_NFS_V4_1)
1046 void nfs_write_prepare(struct rpc_task *task, void *calldata)
1047 {
1048         struct nfs_write_data *data = calldata;
1049
1050         if (nfs4_setup_sequence(NFS_SERVER(data->inode),
1051                                 &data->args.seq_args,
1052                                 &data->res.seq_res, 1, task))
1053                 return;
1054         rpc_call_start(task);
1055 }
1056 #endif /* CONFIG_NFS_V4_1 */
1057
1058 static const struct rpc_call_ops nfs_write_partial_ops = {
1059 #if defined(CONFIG_NFS_V4_1)
1060         .rpc_call_prepare = nfs_write_prepare,
1061 #endif /* CONFIG_NFS_V4_1 */
1062         .rpc_call_done = nfs_writeback_done_partial,
1063         .rpc_release = nfs_writeback_release_partial,
1064 };
1065
1066 /*
1067  * Handle a write reply that flushes a whole page.
1068  *
1069  * FIXME: There is an inherent race with invalidate_inode_pages and
1070  *        writebacks since the page->count is kept > 1 for as long
1071  *        as the page has a write request pending.
1072  */
1073 static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
1074 {
1075         struct nfs_write_data   *data = calldata;
1076
1077         nfs_writeback_done(task, data);
1078 }
1079
1080 static void nfs_writeback_release_full(void *calldata)
1081 {
1082         struct nfs_write_data   *data = calldata;
1083         int status = data->task.tk_status;
1084
1085         /* Update attributes as result of writeback. */
1086         while (!list_empty(&data->pages)) {
1087                 struct nfs_page *req = nfs_list_entry(data->pages.next);
1088                 struct page *page = req->wb_page;
1089
1090                 nfs_list_remove_request(req);
1091
1092                 dprintk("NFS: %5u write (%s/%lld %d@%lld)",
1093                         data->task.tk_pid,
1094                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1095                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1096                         req->wb_bytes,
1097                         (long long)req_offset(req));
1098
1099                 if (status < 0) {
1100                         nfs_set_pageerror(page);
1101                         nfs_context_set_write_error(req->wb_context, status);
1102                         dprintk(", error = %d\n", status);
1103                         goto remove_request;
1104                 }
1105
1106                 if (nfs_write_need_commit(data)) {
1107                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1108                         nfs_mark_request_commit(req);
1109                         dprintk(" marked for commit\n");
1110                         goto next;
1111                 }
1112                 dprintk(" OK\n");
1113 remove_request:
1114                 nfs_inode_remove_request(req);
1115         next:
1116                 nfs_clear_page_tag_locked(req);
1117                 nfs_end_page_writeback(page);
1118         }
1119         nfs_writedata_release(calldata);
1120 }
1121
1122 static const struct rpc_call_ops nfs_write_full_ops = {
1123 #if defined(CONFIG_NFS_V4_1)
1124         .rpc_call_prepare = nfs_write_prepare,
1125 #endif /* CONFIG_NFS_V4_1 */
1126         .rpc_call_done = nfs_writeback_done_full,
1127         .rpc_release = nfs_writeback_release_full,
1128 };
1129
1130
1131 /*
1132  * This function is called when the WRITE call is complete.
1133  */
1134 int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1135 {
1136         struct nfs_writeargs    *argp = &data->args;
1137         struct nfs_writeres     *resp = &data->res;
1138         struct nfs_server       *server = NFS_SERVER(data->inode);
1139         int status;
1140
1141         dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1142                 task->tk_pid, task->tk_status);
1143
1144         /*
1145          * ->write_done will attempt to use post-op attributes to detect
1146          * conflicting writes by other clients.  A strict interpretation
1147          * of close-to-open would allow us to continue caching even if
1148          * another writer had changed the file, but some applications
1149          * depend on tighter cache coherency when writing.
1150          */
1151         status = NFS_PROTO(data->inode)->write_done(task, data);
1152         if (status != 0)
1153                 return status;
1154         nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1155
1156 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1157         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1158                 /* We tried a write call, but the server did not
1159                  * commit data to stable storage even though we
1160                  * requested it.
1161                  * Note: There is a known bug in Tru64 < 5.0 in which
1162                  *       the server reports NFS_DATA_SYNC, but performs
1163                  *       NFS_FILE_SYNC. We therefore implement this checking
1164                  *       as a dprintk() in order to avoid filling syslog.
1165                  */
1166                 static unsigned long    complain;
1167
1168                 if (time_before(complain, jiffies)) {
1169                         dprintk("NFS:       faulty NFS server %s:"
1170                                 " (committed = %d) != (stable = %d)\n",
1171                                 server->nfs_client->cl_hostname,
1172                                 resp->verf->committed, argp->stable);
1173                         complain = jiffies + 300 * HZ;
1174                 }
1175         }
1176 #endif
1177         /* Is this a short write? */
1178         if (task->tk_status >= 0 && resp->count < argp->count) {
1179                 static unsigned long    complain;
1180
1181                 nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
1182
1183                 /* Has the server at least made some progress? */
1184                 if (resp->count != 0) {
1185                         /* Was this an NFSv2 write or an NFSv3 stable write? */
1186                         if (resp->verf->committed != NFS_UNSTABLE) {
1187                                 /* Resend from where the server left off */
1188                                 argp->offset += resp->count;
1189                                 argp->pgbase += resp->count;
1190                                 argp->count -= resp->count;
1191                         } else {
1192                                 /* Resend as a stable write in order to avoid
1193                                  * headaches in the case of a server crash.
1194                                  */
1195                                 argp->stable = NFS_FILE_SYNC;
1196                         }
1197                         nfs_restart_rpc(task, server->nfs_client);
1198                         return -EAGAIN;
1199                 }
1200                 if (time_before(complain, jiffies)) {
1201                         printk(KERN_WARNING
1202                                "NFS: Server wrote zero bytes, expected %u.\n",
1203                                         argp->count);
1204                         complain = jiffies + 300 * HZ;
1205                 }
1206                 /* Can't do anything about it except throw an error. */
1207                 task->tk_status = -EIO;
1208         }
1209         return 0;
1210 }
1211
1212
1213 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1214 static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
1215 {
1216         if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
1217                 return 1;
1218         if (may_wait && !out_of_line_wait_on_bit_lock(&nfsi->flags,
1219                                 NFS_INO_COMMIT, nfs_wait_bit_killable,
1220                                 TASK_KILLABLE))
1221                 return 1;
1222         return 0;
1223 }
1224
1225 static void nfs_commit_clear_lock(struct nfs_inode *nfsi)
1226 {
1227         clear_bit(NFS_INO_COMMIT, &nfsi->flags);
1228         smp_mb__after_clear_bit();
1229         wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
1230 }
1231
1232
1233 static void nfs_commitdata_release(void *data)
1234 {
1235         struct nfs_write_data *wdata = data;
1236
1237         put_nfs_open_context(wdata->args.context);
1238         nfs_commit_free(wdata);
1239 }
1240
1241 /*
1242  * Set up the argument/result storage required for the RPC call.
1243  */
1244 static int nfs_commit_rpcsetup(struct list_head *head,
1245                 struct nfs_write_data *data,
1246                 int how)
1247 {
1248         struct nfs_page *first = nfs_list_entry(head->next);
1249         struct inode *inode = first->wb_context->path.dentry->d_inode;
1250         int priority = flush_task_priority(how);
1251         struct rpc_task *task;
1252         struct rpc_message msg = {
1253                 .rpc_argp = &data->args,
1254                 .rpc_resp = &data->res,
1255                 .rpc_cred = first->wb_context->cred,
1256         };
1257         struct rpc_task_setup task_setup_data = {
1258                 .task = &data->task,
1259                 .rpc_client = NFS_CLIENT(inode),
1260                 .rpc_message = &msg,
1261                 .callback_ops = &nfs_commit_ops,
1262                 .callback_data = data,
1263                 .workqueue = nfsiod_workqueue,
1264                 .flags = RPC_TASK_ASYNC,
1265                 .priority = priority,
1266         };
1267
1268         /* Set up the RPC argument and reply structs
1269          * NB: take care not to mess about with data->commit et al. */
1270
1271         list_splice_init(head, &data->pages);
1272
1273         data->inode       = inode;
1274         data->cred        = msg.rpc_cred;
1275
1276         data->args.fh     = NFS_FH(data->inode);
1277         /* Note: we always request a commit of the entire inode */
1278         data->args.offset = 0;
1279         data->args.count  = 0;
1280         data->args.context = get_nfs_open_context(first->wb_context);
1281         data->res.count   = 0;
1282         data->res.fattr   = &data->fattr;
1283         data->res.verf    = &data->verf;
1284         nfs_fattr_init(&data->fattr);
1285
1286         /* Set up the initial task struct.  */
1287         NFS_PROTO(inode)->commit_setup(data, &msg);
1288
1289         dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1290
1291         task = rpc_run_task(&task_setup_data);
1292         if (IS_ERR(task))
1293                 return PTR_ERR(task);
1294         rpc_put_task(task);
1295         return 0;
1296 }
1297
1298 /*
1299  * Commit dirty pages
1300  */
1301 static int
1302 nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1303 {
1304         struct nfs_write_data   *data;
1305         struct nfs_page         *req;
1306
1307         data = nfs_commitdata_alloc();
1308
1309         if (!data)
1310                 goto out_bad;
1311
1312         /* Set up the argument struct */
1313         return nfs_commit_rpcsetup(head, data, how);
1314  out_bad:
1315         while (!list_empty(head)) {
1316                 req = nfs_list_entry(head->next);
1317                 nfs_list_remove_request(req);
1318                 nfs_mark_request_commit(req);
1319                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1320                 dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
1321                                 BDI_RECLAIMABLE);
1322                 nfs_clear_page_tag_locked(req);
1323         }
1324         nfs_commit_clear_lock(NFS_I(inode));
1325         return -ENOMEM;
1326 }
1327
1328 /*
1329  * COMMIT call returned
1330  */
1331 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1332 {
1333         struct nfs_write_data   *data = calldata;
1334
1335         dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1336                                 task->tk_pid, task->tk_status);
1337
1338         /* Call the NFS version-specific code */
1339         if (NFS_PROTO(data->inode)->commit_done(task, data) != 0)
1340                 return;
1341 }
1342
1343 static void nfs_commit_release(void *calldata)
1344 {
1345         struct nfs_write_data   *data = calldata;
1346         struct nfs_page         *req;
1347         int status = data->task.tk_status;
1348
1349         while (!list_empty(&data->pages)) {
1350                 req = nfs_list_entry(data->pages.next);
1351                 nfs_list_remove_request(req);
1352                 nfs_clear_request_commit(req);
1353
1354                 dprintk("NFS:       commit (%s/%lld %d@%lld)",
1355                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1356                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1357                         req->wb_bytes,
1358                         (long long)req_offset(req));
1359                 if (status < 0) {
1360                         nfs_context_set_write_error(req->wb_context, status);
1361                         nfs_inode_remove_request(req);
1362                         dprintk(", error = %d\n", status);
1363                         goto next;
1364                 }
1365
1366                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1367                  * returned by the server against all stored verfs. */
1368                 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1369                         /* We have a match */
1370                         nfs_inode_remove_request(req);
1371                         dprintk(" OK\n");
1372                         goto next;
1373                 }
1374                 /* We have a mismatch. Write the page again */
1375                 dprintk(" mismatch\n");
1376                 nfs_mark_request_dirty(req);
1377         next:
1378                 nfs_clear_page_tag_locked(req);
1379         }
1380         nfs_commit_clear_lock(NFS_I(data->inode));
1381         nfs_commitdata_release(calldata);
1382 }
1383
1384 static const struct rpc_call_ops nfs_commit_ops = {
1385 #if defined(CONFIG_NFS_V4_1)
1386         .rpc_call_prepare = nfs_write_prepare,
1387 #endif /* CONFIG_NFS_V4_1 */
1388         .rpc_call_done = nfs_commit_done,
1389         .rpc_release = nfs_commit_release,
1390 };
1391
1392 int nfs_commit_inode(struct inode *inode, int how)
1393 {
1394         LIST_HEAD(head);
1395         int may_wait = how & FLUSH_SYNC;
1396         int res = 0;
1397
1398         if (!nfs_commit_set_lock(NFS_I(inode), may_wait))
1399                 goto out_mark_dirty;
1400         spin_lock(&inode->i_lock);
1401         res = nfs_scan_commit(inode, &head, 0, 0);
1402         spin_unlock(&inode->i_lock);
1403         if (res) {
1404                 int error = nfs_commit_list(inode, &head, how);
1405                 if (error < 0)
1406                         return error;
1407                 if (may_wait)
1408                         wait_on_bit(&NFS_I(inode)->flags, NFS_INO_COMMIT,
1409                                         nfs_wait_bit_killable,
1410                                         TASK_KILLABLE);
1411                 else
1412                         goto out_mark_dirty;
1413         } else
1414                 nfs_commit_clear_lock(NFS_I(inode));
1415         return res;
1416         /* Note: If we exit without ensuring that the commit is complete,
1417          * we must mark the inode as dirty. Otherwise, future calls to
1418          * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
1419          * that the data is on the disk.
1420          */
1421 out_mark_dirty:
1422         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1423         return res;
1424 }
1425
1426 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1427 {
1428         struct nfs_inode *nfsi = NFS_I(inode);
1429         int flags = FLUSH_SYNC;
1430         int ret = 0;
1431
1432         if (wbc->sync_mode == WB_SYNC_NONE) {
1433                 /* Don't commit yet if this is a non-blocking flush and there
1434                  * are a lot of outstanding writes for this mapping.
1435                  */
1436                 if (nfsi->ncommit <= (nfsi->npages >> 1))
1437                         goto out_mark_dirty;
1438
1439                 /* don't wait for the COMMIT response */
1440                 flags = 0;
1441         }
1442
1443         ret = nfs_commit_inode(inode, flags);
1444         if (ret >= 0) {
1445                 if (wbc->sync_mode == WB_SYNC_NONE) {
1446                         if (ret < wbc->nr_to_write)
1447                                 wbc->nr_to_write -= ret;
1448                         else
1449                                 wbc->nr_to_write = 0;
1450                 }
1451                 return 0;
1452         }
1453 out_mark_dirty:
1454         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1455         return ret;
1456 }
1457 #else
1458 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1459 {
1460         return 0;
1461 }
1462 #endif
1463
1464 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1465 {
1466         return nfs_commit_unstable_pages(inode, wbc);
1467 }
1468
1469 /*
1470  * flush the inode to disk.
1471  */
1472 int nfs_wb_all(struct inode *inode)
1473 {
1474         struct writeback_control wbc = {
1475                 .sync_mode = WB_SYNC_ALL,
1476                 .nr_to_write = LONG_MAX,
1477                 .range_start = 0,
1478                 .range_end = LLONG_MAX,
1479         };
1480
1481         return sync_inode(inode, &wbc);
1482 }
1483
1484 int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1485 {
1486         struct nfs_page *req;
1487         int ret = 0;
1488
1489         BUG_ON(!PageLocked(page));
1490         for (;;) {
1491                 wait_on_page_writeback(page);
1492                 req = nfs_page_find_request(page);
1493                 if (req == NULL)
1494                         break;
1495                 if (nfs_lock_request_dontget(req)) {
1496                         nfs_inode_remove_request(req);
1497                         /*
1498                          * In case nfs_inode_remove_request has marked the
1499                          * page as being dirty
1500                          */
1501                         cancel_dirty_page(page, PAGE_CACHE_SIZE);
1502                         nfs_unlock_request(req);
1503                         break;
1504                 }
1505                 ret = nfs_wait_on_request(req);
1506                 nfs_release_request(req);
1507                 if (ret < 0)
1508                         break;
1509         }
1510         return ret;
1511 }
1512
1513 /*
1514  * Write back all requests on one page - we do this before reading it.
1515  */
1516 int nfs_wb_page(struct inode *inode, struct page *page)
1517 {
1518         loff_t range_start = page_offset(page);
1519         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1520         struct writeback_control wbc = {
1521                 .sync_mode = WB_SYNC_ALL,
1522                 .nr_to_write = 0,
1523                 .range_start = range_start,
1524                 .range_end = range_end,
1525         };
1526         int ret;
1527
1528         for (;;) {
1529                 wait_on_page_writeback(page);
1530                 if (clear_page_dirty_for_io(page)) {
1531                         ret = nfs_writepage_locked(page, &wbc);
1532                         if (ret < 0)
1533                                 goto out_error;
1534                         continue;
1535                 }
1536                 if (!PagePrivate(page))
1537                         break;
1538                 ret = nfs_commit_inode(inode, FLUSH_SYNC);
1539                 if (ret < 0)
1540                         goto out_error;
1541         }
1542         return 0;
1543 out_error:
1544         return ret;
1545 }
1546
1547 #ifdef CONFIG_MIGRATION
1548 int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
1549                 struct page *page)
1550 {
1551         struct nfs_page *req;
1552         int ret;
1553
1554         nfs_fscache_release_page(page, GFP_KERNEL);
1555
1556         req = nfs_find_and_lock_request(page, false);
1557         ret = PTR_ERR(req);
1558         if (IS_ERR(req))
1559                 goto out;
1560
1561         ret = migrate_page(mapping, newpage, page);
1562         if (!req)
1563                 goto out;
1564         if (ret)
1565                 goto out_unlock;
1566         page_cache_get(newpage);
1567         spin_lock(&mapping->host->i_lock);
1568         req->wb_page = newpage;
1569         SetPagePrivate(newpage);
1570         set_page_private(newpage, (unsigned long)req);
1571         ClearPagePrivate(page);
1572         set_page_private(page, 0);
1573         spin_unlock(&mapping->host->i_lock);
1574         page_cache_release(page);
1575 out_unlock:
1576         nfs_clear_page_tag_locked(req);
1577 out:
1578         return ret;
1579 }
1580 #endif
1581
1582 int __init nfs_init_writepagecache(void)
1583 {
1584         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1585                                              sizeof(struct nfs_write_data),
1586                                              0, SLAB_HWCACHE_ALIGN,
1587                                              NULL);
1588         if (nfs_wdata_cachep == NULL)
1589                 return -ENOMEM;
1590
1591         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1592                                                      nfs_wdata_cachep);
1593         if (nfs_wdata_mempool == NULL)
1594                 return -ENOMEM;
1595
1596         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1597                                                       nfs_wdata_cachep);
1598         if (nfs_commit_mempool == NULL)
1599                 return -ENOMEM;
1600
1601         /*
1602          * NFS congestion size, scale with available memory.
1603          *
1604          *  64MB:    8192k
1605          * 128MB:   11585k
1606          * 256MB:   16384k
1607          * 512MB:   23170k
1608          *   1GB:   32768k
1609          *   2GB:   46340k
1610          *   4GB:   65536k
1611          *   8GB:   92681k
1612          *  16GB:  131072k
1613          *
1614          * This allows larger machines to have larger/more transfers.
1615          * Limit the default to 256M
1616          */
1617         nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1618         if (nfs_congestion_kb > 256*1024)
1619                 nfs_congestion_kb = 256*1024;
1620
1621         return 0;
1622 }
1623
1624 void nfs_destroy_writepagecache(void)
1625 {
1626         mempool_destroy(nfs_commit_mempool);
1627         mempool_destroy(nfs_wdata_mempool);
1628         kmem_cache_destroy(nfs_wdata_cachep);
1629 }
1630