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 #include "pnfs.h"
  32
  33 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  34
  35 #define MIN_POOL_WRITE          (32)
  36 #define MIN_POOL_COMMIT         (4)
  37
  38 /*
  39  * Local function declarations
  40  */
  41 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *desc,
  42                                   struct inode *inode, int ioflags);
  43 static void nfs_redirty_request(struct nfs_page *req);
  44 static const struct rpc_call_ops nfs_write_partial_ops;
  45 static const struct rpc_call_ops nfs_write_full_ops;
  46 static const struct rpc_call_ops nfs_commit_ops;
  47
  48 static struct kmem_cache *nfs_wdata_cachep;
  49 static mempool_t *nfs_wdata_mempool;
  50 static mempool_t *nfs_commit_mempool;
  51
  52 struct nfs_write_data *nfs_commitdata_alloc(void)
  53 {
  54         struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
  55
  56         if (p) {
  57                 memset(p, 0, sizeof(*p));
  58                 INIT_LIST_HEAD(&p->pages);
  59         }
  60         return p;
  61 }
  62 EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
  63
  64 void nfs_commit_free(struct nfs_write_data *p)
  65 {
  66         if (p && (p->pagevec != &p->page_array[0]))
  67                 kfree(p->pagevec);
  68         mempool_free(p, nfs_commit_mempool);
  69 }
  70 EXPORT_SYMBOL_GPL(nfs_commit_free);
  71
  72 struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
  73 {
  74         struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
  75
  76         if (p) {
  77                 memset(p, 0, sizeof(*p));
  78                 INIT_LIST_HEAD(&p->pages);
  79                 p->npages = pagecount;
  80                 if (pagecount <= ARRAY_SIZE(p->page_array))
  81                         p->pagevec = p->page_array;
  82                 else {
  83                         p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
  84                         if (!p->pagevec) {
  85                                 mempool_free(p, nfs_wdata_mempool);
  86                                 p = NULL;
  87                         }
  88                 }
  89         }
  90         return p;
  91 }
  92
  93 void nfs_writedata_free(struct nfs_write_data *p)
  94 {
  95         if (p && (p->pagevec != &p->page_array[0]))
  96                 kfree(p->pagevec);
  97         mempool_free(p, nfs_wdata_mempool);
  98 }
  99
 100 static void nfs_writedata_release(struct nfs_write_data *wdata)
 101 {
 102         put_lseg(wdata->lseg);
 103         put_nfs_open_context(wdata->args.context);
 104         nfs_writedata_free(wdata);
 105 }
 106
 107 static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
 108 {
 109         ctx->error = error;
 110         smp_wmb();
 111         set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 112 }
 113
 114 static struct nfs_page *nfs_page_find_request_locked(struct page *page)
 115 {
 116         struct nfs_page *req = NULL;
 117
 118         if (PagePrivate(page)) {
 119                 req = (struct nfs_page *)page_private(page);
 120                 if (req != NULL)
 121                         kref_get(&req->wb_kref);
 122         }
 123         return req;
 124 }
 125
 126 static struct nfs_page *nfs_page_find_request(struct page *page)
 127 {
 128         struct inode *inode = page->mapping->host;
 129         struct nfs_page *req = NULL;
 130
 131         spin_lock(&inode->i_lock);
 132         req = nfs_page_find_request_locked(page);
 133         spin_unlock(&inode->i_lock);
 134         return req;
 135 }
 136
 137 /* Adjust the file length if we're writing beyond the end */
 138 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 139 {
 140         struct inode *inode = page->mapping->host;
 141         loff_t end, i_size;
 142         pgoff_t end_index;
 143
 144         spin_lock(&inode->i_lock);
 145         i_size = i_size_read(inode);
 146         end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 147         if (i_size > 0 && page->index < end_index)
 148                 goto out;
 149         end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
 150         if (i_size >= end)
 151                 goto out;
 152         i_size_write(inode, end);
 153         nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 154 out:
 155         spin_unlock(&inode->i_lock);
 156 }
 157
 158 /* A writeback failed: mark the page as bad, and invalidate the page cache */
 159 static void nfs_set_pageerror(struct page *page)
 160 {
 161         SetPageError(page);
 162         nfs_zap_mapping(page->mapping->host, page->mapping);
 163 }
 164
 165 /* We can set the PG_uptodate flag if we see that a write request
 166  * covers the full page.
 167  */
 168 static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
 169 {
 170         if (PageUptodate(page))
 171                 return;
 172         if (base != 0)
 173                 return;
 174         if (count != nfs_page_length(page))
 175                 return;
 176         SetPageUptodate(page);
 177 }
 178
 179 static int wb_priority(struct writeback_control *wbc)
 180 {
 181         if (wbc->for_reclaim)
 182                 return FLUSH_HIGHPRI | FLUSH_STABLE;
 183         if (wbc->for_kupdate || wbc->for_background)
 184                 return FLUSH_LOWPRI | FLUSH_COND_STABLE;
 185         return FLUSH_COND_STABLE;
 186 }
 187
 188 /*
 189  * NFS congestion control
 190  */
 191
 192 int nfs_congestion_kb;
 193
 194 #define NFS_CONGESTION_ON_THRESH        (nfs_congestion_kb >> (PAGE_SHIFT-10))
 195 #define NFS_CONGESTION_OFF_THRESH       \
 196         (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 197
 198 static int nfs_set_page_writeback(struct page *page)
 199 {
 200         int ret = test_set_page_writeback(page);
 201
 202         if (!ret) {
 203                 struct inode *inode = page->mapping->host;
 204                 struct nfs_server *nfss = NFS_SERVER(inode);
 205
 206                 page_cache_get(page);
 207                 if (atomic_long_inc_return(&nfss->writeback) >
 208                                 NFS_CONGESTION_ON_THRESH) {
 209                         set_bdi_congested(&nfss->backing_dev_info,
 210                                                 BLK_RW_ASYNC);
 211                 }
 212         }
 213         return ret;
 214 }
 215
 216 static void nfs_end_page_writeback(struct page *page)
 217 {
 218         struct inode *inode = page->mapping->host;
 219         struct nfs_server *nfss = NFS_SERVER(inode);
 220
 221         end_page_writeback(page);
 222         page_cache_release(page);
 223         if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 224                 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
 225 }
 226
 227 static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
 228 {
 229         struct inode *inode = page->mapping->host;
 230         struct nfs_page *req;
 231         int ret;
 232
 233         spin_lock(&inode->i_lock);
 234         for (;;) {
 235                 req = nfs_page_find_request_locked(page);
 236                 if (req == NULL)
 237                         break;
 238                 if (nfs_set_page_tag_locked(req))
 239                         break;
 240                 /* Note: If we hold the page lock, as is the case in nfs_writepage,
 241                  *       then the call to nfs_set_page_tag_locked() will always
 242                  *       succeed provided that someone hasn't already marked the
 243                  *       request as dirty (in which case we don't care).
 244                  */
 245                 spin_unlock(&inode->i_lock);
 246                 if (!nonblock)
 247                         ret = nfs_wait_on_request(req);
 248                 else
 249                         ret = -EAGAIN;
 250                 nfs_release_request(req);
 251                 if (ret != 0)
 252                         return ERR_PTR(ret);
 253                 spin_lock(&inode->i_lock);
 254         }
 255         spin_unlock(&inode->i_lock);
 256         return req;
 257 }
 258
 259 /*
 260  * Find an associated nfs write request, and prepare to flush it out
 261  * May return an error if the user signalled nfs_wait_on_request().
 262  */
 263 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 264                                 struct page *page, bool nonblock)
 265 {
 266         struct nfs_page *req;
 267         int ret = 0;
 268
 269         req = nfs_find_and_lock_request(page, nonblock);
 270         if (!req)
 271                 goto out;
 272         ret = PTR_ERR(req);
 273         if (IS_ERR(req))
 274                 goto out;
 275
 276         ret = nfs_set_page_writeback(page);
 277         BUG_ON(ret != 0);
 278         BUG_ON(test_bit(PG_CLEAN, &req->wb_flags));
 279
 280         if (!nfs_pageio_add_request(pgio, req)) {
 281                 nfs_redirty_request(req);
 282                 ret = pgio->pg_error;
 283         }
 284 out:
 285         return ret;
 286 }
 287
 288 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
 289 {
 290         struct inode *inode = page->mapping->host;
 291         int ret;
 292
 293         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 294         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 295
 296         nfs_pageio_cond_complete(pgio, page->index);
 297         ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
 298         if (ret == -EAGAIN) {
 299                 redirty_page_for_writepage(wbc, page);
 300                 ret = 0;
 301         }
 302         return ret;
 303 }
 304
 305 /*
 306  * Write an mmapped page to the server.
 307  */
 308 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 309 {
 310         struct nfs_pageio_descriptor pgio;
 311         int err;
 312
 313         nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc));
 314         err = nfs_do_writepage(page, wbc, &pgio);
 315         nfs_pageio_complete(&pgio);
 316         if (err < 0)
 317                 return err;
 318         if (pgio.pg_error < 0)
 319                 return pgio.pg_error;
 320         return 0;
 321 }
 322
 323 int nfs_writepage(struct page *page, struct writeback_control *wbc)
 324 {
 325         int ret;
 326
 327         ret = nfs_writepage_locked(page, wbc);
 328         unlock_page(page);
 329         return ret;
 330 }
 331
 332 static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
 333 {
 334         int ret;
 335
 336         ret = nfs_do_writepage(page, wbc, data);
 337         unlock_page(page);
 338         return ret;
 339 }
 340
 341 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 342 {
 343         struct inode *inode = mapping->host;
 344         unsigned long *bitlock = &NFS_I(inode)->flags;
 345         struct nfs_pageio_descriptor pgio;
 346         int err;
 347
 348         /* Stop dirtying of new pages while we sync */
 349         err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
 350                         nfs_wait_bit_killable, TASK_KILLABLE);
 351         if (err)
 352                 goto out_err;
 353
 354         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 355
 356         nfs_pageio_init_write(&pgio, inode, wb_priority(wbc));
 357         err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
 358         nfs_pageio_complete(&pgio);
 359
 360         clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
 361         smp_mb__after_clear_bit();
 362         wake_up_bit(bitlock, NFS_INO_FLUSHING);
 363
 364         if (err < 0)
 365                 goto out_err;
 366         err = pgio.pg_error;
 367         if (err < 0)
 368                 goto out_err;
 369         return 0;
 370 out_err:
 371         return err;
 372 }
 373
 374 /*
 375  * Insert a write request into an inode
 376  */
 377 static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 378 {
 379         struct nfs_inode *nfsi = NFS_I(inode);
 380         int error;
 381
 382         error = radix_tree_preload(GFP_NOFS);
 383         if (error != 0)
 384                 goto out;
 385
 386         /* Lock the request! */
 387         nfs_lock_request_dontget(req);
 388
 389         spin_lock(&inode->i_lock);
 390         error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
 391         BUG_ON(error);
 392         if (!nfsi->npages) {
 393                 igrab(inode);
 394                 if (nfs_have_delegation(inode, FMODE_WRITE))
 395                         nfsi->change_attr++;
 396         }
 397         set_bit(PG_MAPPED, &req->wb_flags);
 398         SetPagePrivate(req->wb_page);
 399         set_page_private(req->wb_page, (unsigned long)req);
 400         nfsi->npages++;
 401         kref_get(&req->wb_kref);
 402         radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
 403                                 NFS_PAGE_TAG_LOCKED);
 404         spin_unlock(&inode->i_lock);
 405         radix_tree_preload_end();
 406 out:
 407         return error;
 408 }
 409
 410 /*
 411  * Remove a write request from an inode
 412  */
 413 static void nfs_inode_remove_request(struct nfs_page *req)
 414 {
 415         struct inode *inode = req->wb_context->path.dentry->d_inode;
 416         struct nfs_inode *nfsi = NFS_I(inode);
 417
 418         BUG_ON (!NFS_WBACK_BUSY(req));
 419
 420         spin_lock(&inode->i_lock);
 421         set_page_private(req->wb_page, 0);
 422         ClearPagePrivate(req->wb_page);
 423         clear_bit(PG_MAPPED, &req->wb_flags);
 424         radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
 425         nfsi->npages--;
 426         if (!nfsi->npages) {
 427                 spin_unlock(&inode->i_lock);
 428                 iput(inode);
 429         } else
 430                 spin_unlock(&inode->i_lock);
 431         nfs_release_request(req);
 432 }
 433
 434 static void
 435 nfs_mark_request_dirty(struct nfs_page *req)
 436 {
 437         __set_page_dirty_nobuffers(req->wb_page);
 438         __mark_inode_dirty(req->wb_page->mapping->host, I_DIRTY_DATASYNC);
 439 }
 440
 441 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 442 /*
 443  * Add a request to the inode's commit list.
 444  */
 445 static void
 446 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
 447 {
 448         struct inode *inode = req->wb_context->path.dentry->d_inode;
 449         struct nfs_inode *nfsi = NFS_I(inode);
 450
 451         spin_lock(&inode->i_lock);
 452         set_bit(PG_CLEAN, &(req)->wb_flags);
 453         radix_tree_tag_set(&nfsi->nfs_page_tree,
 454                         req->wb_index,
 455                         NFS_PAGE_TAG_COMMIT);
 456         nfsi->ncommit++;
 457         spin_unlock(&inode->i_lock);
 458         pnfs_mark_request_commit(req, lseg);
 459         inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 460         inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 461         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 462 }
 463
 464 static int
 465 nfs_clear_request_commit(struct nfs_page *req)
 466 {
 467         struct page *page = req->wb_page;
 468
 469         if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
 470                 dec_zone_page_state(page, NR_UNSTABLE_NFS);
 471                 dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 472                 return 1;
 473         }
 474         return 0;
 475 }
 476
 477 static inline
 478 int nfs_write_need_commit(struct nfs_write_data *data)
 479 {
 480         if (data->verf.committed == NFS_DATA_SYNC)
 481                 return data->lseg == NULL;
 482         else
 483                 return data->verf.committed != NFS_FILE_SYNC;
 484 }
 485
 486 static inline
 487 int nfs_reschedule_unstable_write(struct nfs_page *req,
 488                                   struct nfs_write_data *data)
 489 {
 490         if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {
 491                 nfs_mark_request_commit(req, data->lseg);
 492                 return 1;
 493         }
 494         if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
 495                 nfs_mark_request_dirty(req);
 496                 return 1;
 497         }
 498         return 0;
 499 }
 500 #else
 501 static inline void
 502 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
 503 {
 504 }
 505
 506 static inline int
 507 nfs_clear_request_commit(struct nfs_page *req)
 508 {
 509         return 0;
 510 }
 511
 512 static inline
 513 int nfs_write_need_commit(struct nfs_write_data *data)
 514 {
 515         return 0;
 516 }
 517
 518 static inline
 519 int nfs_reschedule_unstable_write(struct nfs_page *req,
 520                                   struct nfs_write_data *data)
 521 {
 522         return 0;
 523 }
 524 #endif
 525
 526 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 527 static int
 528 nfs_need_commit(struct nfs_inode *nfsi)
 529 {
 530         return radix_tree_tagged(&nfsi->nfs_page_tree, NFS_PAGE_TAG_COMMIT);
 531 }
 532
 533 /*
 534  * nfs_scan_commit - Scan an inode for commit requests
 535  * @inode: NFS inode to scan
 536  * @dst: destination list
 537  * @idx_start: lower bound of page->index to scan.
 538  * @npages: idx_start + npages sets the upper bound to scan.
 539  *
 540  * Moves requests from the inode's 'commit' request list.
 541  * The requests are *not* checked to ensure that they form a contiguous set.
 542  */
 543 static int
 544 nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 545 {
 546         struct nfs_inode *nfsi = NFS_I(inode);
 547         int ret;
 548
 549         if (!nfs_need_commit(nfsi))
 550                 return 0;
 551
 552         ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
 553         if (ret > 0)
 554                 nfsi->ncommit -= ret;
 555         if (nfs_need_commit(NFS_I(inode)))
 556                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 557         return ret;
 558 }
 559 #else
 560 static inline int nfs_need_commit(struct nfs_inode *nfsi)
 561 {
 562         return 0;
 563 }
 564
 565 static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 566 {
 567         return 0;
 568 }
 569 #endif
 570
 571 /*
 572  * Search for an existing write request, and attempt to update
 573  * it to reflect a new dirty region on a given page.
 574  *
 575  * If the attempt fails, then the existing request is flushed out
 576  * to disk.
 577  */
 578 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
 579                 struct page *page,
 580                 unsigned int offset,
 581                 unsigned int bytes)
 582 {
 583         struct nfs_page *req;
 584         unsigned int rqend;
 585         unsigned int end;
 586         int error;
 587
 588         if (!PagePrivate(page))
 589                 return NULL;
 590
 591         end = offset + bytes;
 592         spin_lock(&inode->i_lock);
 593
 594         for (;;) {
 595                 req = nfs_page_find_request_locked(page);
 596                 if (req == NULL)
 597                         goto out_unlock;
 598
 599                 rqend = req->wb_offset + req->wb_bytes;
 600                 /*
 601                  * Tell the caller to flush out the request if
 602                  * the offsets are non-contiguous.
 603                  * Note: nfs_flush_incompatible() will already
 604                  * have flushed out requests having wrong owners.
 605                  */
 606                 if (offset > rqend
 607                     || end < req->wb_offset)
 608                         goto out_flushme;
 609
 610                 if (nfs_set_page_tag_locked(req))
 611                         break;
 612
 613                 /* The request is locked, so wait and then retry */
 614                 spin_unlock(&inode->i_lock);
 615                 error = nfs_wait_on_request(req);
 616                 nfs_release_request(req);
 617                 if (error != 0)
 618                         goto out_err;
 619                 spin_lock(&inode->i_lock);
 620         }
 621
 622         if (nfs_clear_request_commit(req) &&
 623             radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
 624                                  req->wb_index, NFS_PAGE_TAG_COMMIT) != NULL) {
 625                 NFS_I(inode)->ncommit--;
 626                 pnfs_clear_request_commit(req);
 627         }
 628
 629         /* Okay, the request matches. Update the region */
 630         if (offset < req->wb_offset) {
 631                 req->wb_offset = offset;
 632                 req->wb_pgbase = offset;
 633         }
 634         if (end > rqend)
 635                 req->wb_bytes = end - req->wb_offset;
 636         else
 637                 req->wb_bytes = rqend - req->wb_offset;
 638 out_unlock:
 639         spin_unlock(&inode->i_lock);
 640         return req;
 641 out_flushme:
 642         spin_unlock(&inode->i_lock);
 643         nfs_release_request(req);
 644         error = nfs_wb_page(inode, page);
 645 out_err:
 646         return ERR_PTR(error);
 647 }
 648
 649 /*
 650  * Try to update an existing write request, or create one if there is none.
 651  *
 652  * Note: Should always be called with the Page Lock held to prevent races
 653  * if we have to add a new request. Also assumes that the caller has
 654  * already called nfs_flush_incompatible() if necessary.
 655  */
 656 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
 657                 struct page *page, unsigned int offset, unsigned int bytes)
 658 {
 659         struct inode *inode = page->mapping->host;
 660         struct nfs_page *req;
 661         int error;
 662
 663         req = nfs_try_to_update_request(inode, page, offset, bytes);
 664         if (req != NULL)
 665                 goto out;
 666         req = nfs_create_request(ctx, inode, page, offset, bytes);
 667         if (IS_ERR(req))
 668                 goto out;
 669         error = nfs_inode_add_request(inode, req);
 670         if (error != 0) {
 671                 nfs_release_request(req);
 672                 req = ERR_PTR(error);
 673         }
 674 out:
 675         return req;
 676 }
 677
 678 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 679                 unsigned int offset, unsigned int count)
 680 {
 681         struct nfs_page *req;
 682
 683         req = nfs_setup_write_request(ctx, page, offset, count);
 684         if (IS_ERR(req))
 685                 return PTR_ERR(req);
 686         nfs_mark_request_dirty(req);
 687         /* Update file length */
 688         nfs_grow_file(page, offset, count);
 689         nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
 690         nfs_mark_request_dirty(req);
 691         nfs_clear_page_tag_locked(req);
 692         return 0;
 693 }
 694
 695 int nfs_flush_incompatible(struct file *file, struct page *page)
 696 {
 697         struct nfs_open_context *ctx = nfs_file_open_context(file);
 698         struct nfs_page *req;
 699         int do_flush, status;
 700         /*
 701          * Look for a request corresponding to this page. If there
 702          * is one, and it belongs to another file, we flush it out
 703          * before we try to copy anything into the page. Do this
 704          * due to the lack of an ACCESS-type call in NFSv2.
 705          * Also do the same if we find a request from an existing
 706          * dropped page.
 707          */
 708         do {
 709                 req = nfs_page_find_request(page);
 710                 if (req == NULL)
 711                         return 0;
 712                 do_flush = req->wb_page != page || req->wb_context != ctx ||
 713                         req->wb_lock_context->lockowner != current->files ||
 714                         req->wb_lock_context->pid != current->tgid;
 715                 nfs_release_request(req);
 716                 if (!do_flush)
 717                         return 0;
 718                 status = nfs_wb_page(page->mapping->host, page);
 719         } while (status == 0);
 720         return status;
 721 }
 722
 723 /*
 724  * If the page cache is marked as unsafe or invalid, then we can't rely on
 725  * the PageUptodate() flag. In this case, we will need to turn off
 726  * write optimisations that depend on the page contents being correct.
 727  */
 728 static int nfs_write_pageuptodate(struct page *page, struct inode *inode)
 729 {
 730         return PageUptodate(page) &&
 731                 !(NFS_I(inode)->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA));
 732 }
 733
 734 /*
 735  * Update and possibly write a cached page of an NFS file.
 736  *
 737  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
 738  * things with a page scheduled for an RPC call (e.g. invalidate it).
 739  */
 740 int nfs_updatepage(struct file *file, struct page *page,
 741                 unsigned int offset, unsigned int count)
 742 {
 743         struct nfs_open_context *ctx = nfs_file_open_context(file);
 744         struct inode    *inode = page->mapping->host;
 745         int             status = 0;
 746
 747         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 748
 749         dprintk("NFS:       nfs_updatepage(%s/%s %d@%lld)\n",
 750                 file->f_path.dentry->d_parent->d_name.name,
 751                 file->f_path.dentry->d_name.name, count,
 752                 (long long)(page_offset(page) + offset));
 753
 754         /* If we're not using byte range locks, and we know the page
 755          * is up to date, it may be more efficient to extend the write
 756          * to cover the entire page in order to avoid fragmentation
 757          * inefficiencies.
 758          */
 759         if (nfs_write_pageuptodate(page, inode) &&
 760                         inode->i_flock == NULL &&
 761                         !(file->f_flags & O_DSYNC)) {
 762                 count = max(count + offset, nfs_page_length(page));
 763                 offset = 0;
 764         }
 765
 766         status = nfs_writepage_setup(ctx, page, offset, count);
 767         if (status < 0)
 768                 nfs_set_pageerror(page);
 769
 770         dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
 771                         status, (long long)i_size_read(inode));
 772         return status;
 773 }
 774
 775 static void nfs_writepage_release(struct nfs_page *req,
 776                                   struct nfs_write_data *data)
 777 {
 778         struct page *page = req->wb_page;
 779
 780         if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req, data))
 781                 nfs_inode_remove_request(req);
 782         nfs_clear_page_tag_locked(req);
 783         nfs_end_page_writeback(page);
 784 }
 785
 786 static int flush_task_priority(int how)
 787 {
 788         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
 789                 case FLUSH_HIGHPRI:
 790                         return RPC_PRIORITY_HIGH;
 791                 case FLUSH_LOWPRI:
 792                         return RPC_PRIORITY_LOW;
 793         }
 794         return RPC_PRIORITY_NORMAL;
 795 }
 796
 797 int nfs_initiate_write(struct nfs_write_data *data,
 798                        struct rpc_clnt *clnt,
 799                        const struct rpc_call_ops *call_ops,
 800                        int how)
 801 {
 802         struct inode *inode = data->inode;
 803         int priority = flush_task_priority(how);
 804         struct rpc_task *task;
 805         struct rpc_message msg = {
 806                 .rpc_argp = &data->args,
 807                 .rpc_resp = &data->res,
 808                 .rpc_cred = data->cred,
 809         };
 810         struct rpc_task_setup task_setup_data = {
 811                 .rpc_client = clnt,
 812                 .task = &data->task,
 813                 .rpc_message = &msg,
 814                 .callback_ops = call_ops,
 815                 .callback_data = data,
 816                 .workqueue = nfsiod_workqueue,
 817                 .flags = RPC_TASK_ASYNC,
 818                 .priority = priority,
 819         };
 820         int ret = 0;
 821
 822         /* Set up the initial task struct.  */
 823         NFS_PROTO(inode)->write_setup(data, &msg);
 824
 825         dprintk("NFS: %5u initiated write call "
 826                 "(req %s/%lld, %u bytes @ offset %llu)\n",
 827                 data->task.tk_pid,
 828                 inode->i_sb->s_id,
 829                 (long long)NFS_FILEID(inode),
 830                 data->args.count,
 831                 (unsigned long long)data->args.offset);
 832
 833         task = rpc_run_task(&task_setup_data);
 834         if (IS_ERR(task)) {
 835                 ret = PTR_ERR(task);
 836                 goto out;
 837         }
 838         if (how & FLUSH_SYNC) {
 839                 ret = rpc_wait_for_completion_task(task);
 840                 if (ret == 0)
 841                         ret = task->tk_status;
 842         }
 843         rpc_put_task(task);
 844 out:
 845         return ret;
 846 }
 847 EXPORT_SYMBOL_GPL(nfs_initiate_write);
 848
 849 /*
 850  * Set up the argument/result storage required for the RPC call.
 851  */
 852 static int nfs_write_rpcsetup(struct nfs_page *req,
 853                 struct nfs_write_data *data,
 854                 const struct rpc_call_ops *call_ops,
 855                 unsigned int count, unsigned int offset,
 856                 struct pnfs_layout_segment *lseg,
 857                 int how)
 858 {
 859         struct inode *inode = req->wb_context->path.dentry->d_inode;
 860
 861         /* Set up the RPC argument and reply structs
 862          * NB: take care not to mess about with data->commit et al. */
 863
 864         data->req = req;
 865         data->inode = inode = req->wb_context->path.dentry->d_inode;
 866         data->cred = req->wb_context->cred;
 867         data->lseg = get_lseg(lseg);
 868
 869         data->args.fh     = NFS_FH(inode);
 870         data->args.offset = req_offset(req) + offset;
 871         data->args.pgbase = req->wb_pgbase + offset;
 872         data->args.pages  = data->pagevec;
 873         data->args.count  = count;
 874         data->args.context = get_nfs_open_context(req->wb_context);
 875         data->args.lock_context = req->wb_lock_context;
 876         data->args.stable  = NFS_UNSTABLE;
 877         if (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
 878                 data->args.stable = NFS_DATA_SYNC;
 879                 if (!nfs_need_commit(NFS_I(inode)))
 880                         data->args.stable = NFS_FILE_SYNC;
 881         }
 882
 883         data->res.fattr   = &data->fattr;
 884         data->res.count   = count;
 885         data->res.verf    = &data->verf;
 886         nfs_fattr_init(&data->fattr);
 887
 888         if (data->lseg &&
 889             (pnfs_try_to_write_data(data, call_ops, how) == PNFS_ATTEMPTED))
 890                 return 0;
 891
 892         return nfs_initiate_write(data, NFS_CLIENT(inode), call_ops, how);
 893 }
 894
 895 /* If a nfs_flush_* function fails, it should remove reqs from @head and
 896  * call this on each, which will prepare them to be retried on next
 897  * writeback using standard nfs.
 898  */
 899 static void nfs_redirty_request(struct nfs_page *req)
 900 {
 901         struct page *page = req->wb_page;
 902
 903         nfs_mark_request_dirty(req);
 904         nfs_clear_page_tag_locked(req);
 905         nfs_end_page_writeback(page);
 906 }
 907
 908 /*
 909  * Generate multiple small requests to write out a single
 910  * contiguous dirty area on one page.
 911  */
 912 static int nfs_flush_multi(struct nfs_pageio_descriptor *desc)
 913 {
 914         struct nfs_page *req = nfs_list_entry(desc->pg_list.next);
 915         struct page *page = req->wb_page;
 916         struct nfs_write_data *data;
 917         size_t wsize = NFS_SERVER(desc->pg_inode)->wsize, nbytes;
 918         unsigned int offset;
 919         int requests = 0;
 920         int ret = 0;
 921         struct pnfs_layout_segment *lseg;
 922         LIST_HEAD(list);
 923
 924         nfs_list_remove_request(req);
 925
 926         if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
 927             (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit ||
 928              desc->pg_count > wsize))
 929                 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
 930
 931
 932         nbytes = desc->pg_count;
 933         do {
 934                 size_t len = min(nbytes, wsize);
 935
 936                 data = nfs_writedata_alloc(1);
 937                 if (!data)
 938                         goto out_bad;
 939                 list_add(&data->pages, &list);
 940                 requests++;
 941                 nbytes -= len;
 942         } while (nbytes != 0);
 943         atomic_set(&req->wb_complete, requests);
 944
 945         BUG_ON(desc->pg_lseg);
 946         lseg = pnfs_update_layout(desc->pg_inode, req->wb_context, IOMODE_RW);
 947         ClearPageError(page);
 948         offset = 0;
 949         nbytes = desc->pg_count;
 950         do {
 951                 int ret2;
 952
 953                 data = list_entry(list.next, struct nfs_write_data, pages);
 954                 list_del_init(&data->pages);
 955
 956                 data->pagevec[0] = page;
 957
 958                 if (nbytes < wsize)
 959                         wsize = nbytes;
 960                 ret2 = nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
 961                                           wsize, offset, lseg, desc->pg_ioflags);
 962                 if (ret == 0)
 963                         ret = ret2;
 964                 offset += wsize;
 965                 nbytes -= wsize;
 966         } while (nbytes != 0);
 967
 968         put_lseg(lseg);
 969         desc->pg_lseg = NULL;
 970         return ret;
 971
 972 out_bad:
 973         while (!list_empty(&list)) {
 974                 data = list_entry(list.next, struct nfs_write_data, pages);
 975                 list_del(&data->pages);
 976                 nfs_writedata_free(data);
 977         }
 978         nfs_redirty_request(req);
 979         return -ENOMEM;
 980 }
 981
 982 /*
 983  * Create an RPC task for the given write request and kick it.
 984  * The page must have been locked by the caller.
 985  *
 986  * It may happen that the page we're passed is not marked dirty.
 987  * This is the case if nfs_updatepage detects a conflicting request
 988  * that has been written but not committed.
 989  */
 990 static int nfs_flush_one(struct nfs_pageio_descriptor *desc)
 991 {
 992         struct nfs_page         *req;
 993         struct page             **pages;
 994         struct nfs_write_data   *data;
 995         struct list_head *head = &desc->pg_list;
 996         struct pnfs_layout_segment *lseg = desc->pg_lseg;
 997         int ret;
 998
 999         data = nfs_writedata_alloc(nfs_page_array_len(desc->pg_base,
1000                                                       desc->pg_count));
1001         if (!data) {
1002                 while (!list_empty(head)) {
1003                         req = nfs_list_entry(head->next);
1004                         nfs_list_remove_request(req);
1005                         nfs_redirty_request(req);
1006                 }
1007                 ret = -ENOMEM;
1008                 goto out;
1009         }
1010         pages = data->pagevec;
1011         while (!list_empty(head)) {
1012                 req = nfs_list_entry(head->next);
1013                 nfs_list_remove_request(req);
1014                 nfs_list_add_request(req, &data->pages);
1015                 ClearPageError(req->wb_page);
1016                 *pages++ = req->wb_page;
1017         }
1018         req = nfs_list_entry(data->pages.next);
1019         if ((!lseg) && list_is_singular(&data->pages))
1020                 lseg = pnfs_update_layout(desc->pg_inode, req->wb_context, IOMODE_RW);
1021
1022         if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1023             (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit))
1024                 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1025
1026         /* Set up the argument struct */
1027         ret = nfs_write_rpcsetup(req, data, &nfs_write_full_ops, desc->pg_count, 0, lseg, desc->pg_ioflags);
1028 out:
1029         put_lseg(lseg); /* Cleans any gotten in ->pg_test */
1030         desc->pg_lseg = NULL;
1031         return ret;
1032 }
1033
1034 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1035                                   struct inode *inode, int ioflags)
1036 {
1037         size_t wsize = NFS_SERVER(inode)->wsize;
1038
1039         pnfs_pageio_init_write(pgio, inode);
1040
1041         if (wsize < PAGE_CACHE_SIZE)
1042                 nfs_pageio_init(pgio, inode, nfs_flush_multi, wsize, ioflags);
1043         else
1044                 nfs_pageio_init(pgio, inode, nfs_flush_one, wsize, ioflags);
1045 }
1046
1047 /*
1048  * Handle a write reply that flushed part of a page.
1049  */
1050 static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
1051 {
1052         struct nfs_write_data   *data = calldata;
1053
1054         dprintk("NFS: %5u write(%s/%lld %d@%lld)",
1055                 task->tk_pid,
1056                 data->req->wb_context->path.dentry->d_inode->i_sb->s_id,
1057                 (long long)
1058                   NFS_FILEID(data->req->wb_context->path.dentry->d_inode),
1059                 data->req->wb_bytes, (long long)req_offset(data->req));
1060
1061         nfs_writeback_done(task, data);
1062 }
1063
1064 static void nfs_writeback_release_partial(void *calldata)
1065 {
1066         struct nfs_write_data   *data = calldata;
1067         struct nfs_page         *req = data->req;
1068         struct page             *page = req->wb_page;
1069         int status = data->task.tk_status;
1070
1071         if (status < 0) {
1072                 nfs_set_pageerror(page);
1073                 nfs_context_set_write_error(req->wb_context, status);
1074                 dprintk(", error = %d\n", status);
1075                 goto out;
1076         }
1077
1078         if (nfs_write_need_commit(data)) {
1079                 struct inode *inode = page->mapping->host;
1080
1081                 spin_lock(&inode->i_lock);
1082                 if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
1083                         /* Do nothing we need to resend the writes */
1084                 } else if (!test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) {
1085                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1086                         dprintk(" defer commit\n");
1087                 } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
1088                         set_bit(PG_NEED_RESCHED, &req->wb_flags);
1089                         clear_bit(PG_NEED_COMMIT, &req->wb_flags);
1090                         dprintk(" server reboot detected\n");
1091                 }
1092                 spin_unlock(&inode->i_lock);
1093         } else
1094                 dprintk(" OK\n");
1095
1096 out:
1097         if (atomic_dec_and_test(&req->wb_complete))
1098                 nfs_writepage_release(req, data);
1099         nfs_writedata_release(calldata);
1100 }
1101
1102 #if defined(CONFIG_NFS_V4_1)
1103 void nfs_write_prepare(struct rpc_task *task, void *calldata)
1104 {
1105         struct nfs_write_data *data = calldata;
1106
1107         if (nfs4_setup_sequence(NFS_SERVER(data->inode),
1108                                 &data->args.seq_args,
1109                                 &data->res.seq_res, 1, task))
1110                 return;
1111         rpc_call_start(task);
1112 }
1113 #endif /* CONFIG_NFS_V4_1 */
1114
1115 static const struct rpc_call_ops nfs_write_partial_ops = {
1116 #if defined(CONFIG_NFS_V4_1)
1117         .rpc_call_prepare = nfs_write_prepare,
1118 #endif /* CONFIG_NFS_V4_1 */
1119         .rpc_call_done = nfs_writeback_done_partial,
1120         .rpc_release = nfs_writeback_release_partial,
1121 };
1122
1123 /*
1124  * Handle a write reply that flushes a whole page.
1125  *
1126  * FIXME: There is an inherent race with invalidate_inode_pages and
1127  *        writebacks since the page->count is kept > 1 for as long
1128  *        as the page has a write request pending.
1129  */
1130 static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
1131 {
1132         struct nfs_write_data   *data = calldata;
1133
1134         nfs_writeback_done(task, data);
1135 }
1136
1137 static void nfs_writeback_release_full(void *calldata)
1138 {
1139         struct nfs_write_data   *data = calldata;
1140         int status = data->task.tk_status;
1141
1142         /* Update attributes as result of writeback. */
1143         while (!list_empty(&data->pages)) {
1144                 struct nfs_page *req = nfs_list_entry(data->pages.next);
1145                 struct page *page = req->wb_page;
1146
1147                 nfs_list_remove_request(req);
1148
1149                 dprintk("NFS: %5u write (%s/%lld %d@%lld)",
1150                         data->task.tk_pid,
1151                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1152                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1153                         req->wb_bytes,
1154                         (long long)req_offset(req));
1155
1156                 if (status < 0) {
1157                         nfs_set_pageerror(page);
1158                         nfs_context_set_write_error(req->wb_context, status);
1159                         dprintk(", error = %d\n", status);
1160                         goto remove_request;
1161                 }
1162
1163                 if (nfs_write_need_commit(data)) {
1164                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1165                         nfs_mark_request_commit(req, data->lseg);
1166                         dprintk(" marked for commit\n");
1167                         goto next;
1168                 }
1169                 dprintk(" OK\n");
1170 remove_request:
1171                 nfs_inode_remove_request(req);
1172         next:
1173                 nfs_clear_page_tag_locked(req);
1174                 nfs_end_page_writeback(page);
1175         }
1176         nfs_writedata_release(calldata);
1177 }
1178
1179 static const struct rpc_call_ops nfs_write_full_ops = {
1180 #if defined(CONFIG_NFS_V4_1)
1181         .rpc_call_prepare = nfs_write_prepare,
1182 #endif /* CONFIG_NFS_V4_1 */
1183         .rpc_call_done = nfs_writeback_done_full,
1184         .rpc_release = nfs_writeback_release_full,
1185 };
1186
1187
1188 /*
1189  * This function is called when the WRITE call is complete.
1190  */
1191 void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1192 {
1193         struct nfs_writeargs    *argp = &data->args;
1194         struct nfs_writeres     *resp = &data->res;
1195         struct nfs_server       *server = NFS_SERVER(data->inode);
1196         int status;
1197
1198         dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1199                 task->tk_pid, task->tk_status);
1200
1201         /*
1202          * ->write_done will attempt to use post-op attributes to detect
1203          * conflicting writes by other clients.  A strict interpretation
1204          * of close-to-open would allow us to continue caching even if
1205          * another writer had changed the file, but some applications
1206          * depend on tighter cache coherency when writing.
1207          */
1208         status = NFS_PROTO(data->inode)->write_done(task, data);
1209         if (status != 0)
1210                 return;
1211         nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1212
1213 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1214         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1215                 /* We tried a write call, but the server did not
1216                  * commit data to stable storage even though we
1217                  * requested it.
1218                  * Note: There is a known bug in Tru64 < 5.0 in which
1219                  *       the server reports NFS_DATA_SYNC, but performs
1220                  *       NFS_FILE_SYNC. We therefore implement this checking
1221                  *       as a dprintk() in order to avoid filling syslog.
1222                  */
1223                 static unsigned long    complain;
1224
1225                 /* Note this will print the MDS for a DS write */
1226                 if (time_before(complain, jiffies)) {
1227                         dprintk("NFS:       faulty NFS server %s:"
1228                                 " (committed = %d) != (stable = %d)\n",
1229                                 server->nfs_client->cl_hostname,
1230                                 resp->verf->committed, argp->stable);
1231                         complain = jiffies + 300 * HZ;
1232                 }
1233         }
1234 #endif
1235         /* Is this a short write? */
1236         if (task->tk_status >= 0 && resp->count < argp->count) {
1237                 static unsigned long    complain;
1238
1239                 nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
1240
1241                 /* Has the server at least made some progress? */
1242                 if (resp->count != 0) {
1243                         /* Was this an NFSv2 write or an NFSv3 stable write? */
1244                         if (resp->verf->committed != NFS_UNSTABLE) {
1245                                 /* Resend from where the server left off */
1246                                 data->mds_offset += resp->count;
1247                                 argp->offset += resp->count;
1248                                 argp->pgbase += resp->count;
1249                                 argp->count -= resp->count;
1250                         } else {
1251                                 /* Resend as a stable write in order to avoid
1252                                  * headaches in the case of a server crash.
1253                                  */
1254                                 argp->stable = NFS_FILE_SYNC;
1255                         }
1256                         nfs_restart_rpc(task, server->nfs_client);
1257                         return;
1258                 }
1259                 if (time_before(complain, jiffies)) {
1260                         printk(KERN_WARNING
1261                                "NFS: Server wrote zero bytes, expected %u.\n",
1262                                         argp->count);
1263                         complain = jiffies + 300 * HZ;
1264                 }
1265                 /* Can't do anything about it except throw an error. */
1266                 task->tk_status = -EIO;
1267         }
1268         return;
1269 }
1270
1271
1272 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1273 static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
1274 {
1275         int ret;
1276
1277         if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
1278                 return 1;
1279         if (!may_wait)
1280                 return 0;
1281         ret = out_of_line_wait_on_bit_lock(&nfsi->flags,
1282                                 NFS_INO_COMMIT,
1283                                 nfs_wait_bit_killable,
1284                                 TASK_KILLABLE);
1285         return (ret < 0) ? ret : 1;
1286 }
1287
1288 void nfs_commit_clear_lock(struct nfs_inode *nfsi)
1289 {
1290         clear_bit(NFS_INO_COMMIT, &nfsi->flags);
1291         smp_mb__after_clear_bit();
1292         wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
1293 }
1294 EXPORT_SYMBOL_GPL(nfs_commit_clear_lock);
1295
1296 void nfs_commitdata_release(void *data)
1297 {
1298         struct nfs_write_data *wdata = data;
1299
1300         put_lseg(wdata->lseg);
1301         put_nfs_open_context(wdata->args.context);
1302         nfs_commit_free(wdata);
1303 }
1304 EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1305
1306 int nfs_initiate_commit(struct nfs_write_data *data, struct rpc_clnt *clnt,
1307                         const struct rpc_call_ops *call_ops,
1308                         int how)
1309 {
1310         struct rpc_task *task;
1311         int priority = flush_task_priority(how);
1312         struct rpc_message msg = {
1313                 .rpc_argp = &data->args,
1314                 .rpc_resp = &data->res,
1315                 .rpc_cred = data->cred,
1316         };
1317         struct rpc_task_setup task_setup_data = {
1318                 .task = &data->task,
1319                 .rpc_client = clnt,
1320                 .rpc_message = &msg,
1321                 .callback_ops = call_ops,
1322                 .callback_data = data,
1323                 .workqueue = nfsiod_workqueue,
1324                 .flags = RPC_TASK_ASYNC,
1325                 .priority = priority,
1326         };
1327         /* Set up the initial task struct.  */
1328         NFS_PROTO(data->inode)->commit_setup(data, &msg);
1329
1330         dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1331
1332         task = rpc_run_task(&task_setup_data);
1333         if (IS_ERR(task))
1334                 return PTR_ERR(task);
1335         if (how & FLUSH_SYNC)
1336                 rpc_wait_for_completion_task(task);
1337         rpc_put_task(task);
1338         return 0;
1339 }
1340 EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1341
1342 /*
1343  * Set up the argument/result storage required for the RPC call.
1344  */
1345 void nfs_init_commit(struct nfs_write_data *data,
1346                             struct list_head *head,
1347                             struct pnfs_layout_segment *lseg)
1348 {
1349         struct nfs_page *first = nfs_list_entry(head->next);
1350         struct inode *inode = first->wb_context->path.dentry->d_inode;
1351
1352         /* Set up the RPC argument and reply structs
1353          * NB: take care not to mess about with data->commit et al. */
1354
1355         list_splice_init(head, &data->pages);
1356
1357         data->inode       = inode;
1358         data->cred        = first->wb_context->cred;
1359         data->lseg        = lseg; /* reference transferred */
1360         data->mds_ops     = &nfs_commit_ops;
1361
1362         data->args.fh     = NFS_FH(data->inode);
1363         /* Note: we always request a commit of the entire inode */
1364         data->args.offset = 0;
1365         data->args.count  = 0;
1366         data->args.context = get_nfs_open_context(first->wb_context);
1367         data->res.count   = 0;
1368         data->res.fattr   = &data->fattr;
1369         data->res.verf    = &data->verf;
1370         nfs_fattr_init(&data->fattr);
1371 }
1372 EXPORT_SYMBOL_GPL(nfs_init_commit);
1373
1374 void nfs_retry_commit(struct list_head *page_list,
1375                       struct pnfs_layout_segment *lseg)
1376 {
1377         struct nfs_page *req;
1378
1379         while (!list_empty(page_list)) {
1380                 req = nfs_list_entry(page_list->next);
1381                 nfs_list_remove_request(req);
1382                 nfs_mark_request_commit(req, lseg);
1383                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1384                 dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
1385                              BDI_RECLAIMABLE);
1386                 nfs_clear_page_tag_locked(req);
1387         }
1388 }
1389 EXPORT_SYMBOL_GPL(nfs_retry_commit);
1390
1391 /*
1392  * Commit dirty pages
1393  */
1394 static int
1395 nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1396 {
1397         struct nfs_write_data   *data;
1398
1399         data = nfs_commitdata_alloc();
1400
1401         if (!data)
1402                 goto out_bad;
1403
1404         /* Set up the argument struct */
1405         nfs_init_commit(data, head, NULL);
1406         return nfs_initiate_commit(data, NFS_CLIENT(inode), data->mds_ops, how);
1407  out_bad:
1408         nfs_retry_commit(head, NULL);
1409         nfs_commit_clear_lock(NFS_I(inode));
1410         return -ENOMEM;
1411 }
1412
1413 /*
1414  * COMMIT call returned
1415  */
1416 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1417 {
1418         struct nfs_write_data   *data = calldata;
1419
1420         dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1421                                 task->tk_pid, task->tk_status);
1422
1423         /* Call the NFS version-specific code */
1424         if (NFS_PROTO(data->inode)->commit_done(task, data) != 0)
1425                 return;
1426 }
1427
1428 void nfs_commit_release_pages(struct nfs_write_data *data)
1429 {
1430         struct nfs_page *req;
1431         int status = data->task.tk_status;
1432
1433         while (!list_empty(&data->pages)) {
1434                 req = nfs_list_entry(data->pages.next);
1435                 nfs_list_remove_request(req);
1436                 nfs_clear_request_commit(req);
1437
1438                 dprintk("NFS:       commit (%s/%lld %d@%lld)",
1439                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1440                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1441                         req->wb_bytes,
1442                         (long long)req_offset(req));
1443                 if (status < 0) {
1444                         nfs_context_set_write_error(req->wb_context, status);
1445                         nfs_inode_remove_request(req);
1446                         dprintk(", error = %d\n", status);
1447                         goto next;
1448                 }
1449
1450                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1451                  * returned by the server against all stored verfs. */
1452                 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1453                         /* We have a match */
1454                         nfs_inode_remove_request(req);
1455                         dprintk(" OK\n");
1456                         goto next;
1457                 }
1458                 /* We have a mismatch. Write the page again */
1459                 dprintk(" mismatch\n");
1460                 nfs_mark_request_dirty(req);
1461         next:
1462                 nfs_clear_page_tag_locked(req);
1463         }
1464 }
1465 EXPORT_SYMBOL_GPL(nfs_commit_release_pages);
1466
1467 static void nfs_commit_release(void *calldata)
1468 {
1469         struct nfs_write_data *data = calldata;
1470
1471         nfs_commit_release_pages(data);
1472         nfs_commit_clear_lock(NFS_I(data->inode));
1473         nfs_commitdata_release(calldata);
1474 }
1475
1476 static const struct rpc_call_ops nfs_commit_ops = {
1477 #if defined(CONFIG_NFS_V4_1)
1478         .rpc_call_prepare = nfs_write_prepare,
1479 #endif /* CONFIG_NFS_V4_1 */
1480         .rpc_call_done = nfs_commit_done,
1481         .rpc_release = nfs_commit_release,
1482 };
1483
1484 int nfs_commit_inode(struct inode *inode, int how)
1485 {
1486         LIST_HEAD(head);
1487         int may_wait = how & FLUSH_SYNC;
1488         int res;
1489
1490         res = nfs_commit_set_lock(NFS_I(inode), may_wait);
1491         if (res <= 0)
1492                 goto out_mark_dirty;
1493         spin_lock(&inode->i_lock);
1494         res = nfs_scan_commit(inode, &head, 0, 0);
1495         spin_unlock(&inode->i_lock);
1496         if (res) {
1497                 int error;
1498
1499                 error = pnfs_commit_list(inode, &head, how);
1500                 if (error == PNFS_NOT_ATTEMPTED)
1501                         error = nfs_commit_list(inode, &head, how);
1502                 if (error < 0)
1503                         return error;
1504                 if (!may_wait)
1505                         goto out_mark_dirty;
1506                 error = wait_on_bit(&NFS_I(inode)->flags,
1507                                 NFS_INO_COMMIT,
1508                                 nfs_wait_bit_killable,
1509                                 TASK_KILLABLE);
1510                 if (error < 0)
1511                         return error;
1512         } else
1513                 nfs_commit_clear_lock(NFS_I(inode));
1514         return res;
1515         /* Note: If we exit without ensuring that the commit is complete,
1516          * we must mark the inode as dirty. Otherwise, future calls to
1517          * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
1518          * that the data is on the disk.
1519          */
1520 out_mark_dirty:
1521         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1522         return res;
1523 }
1524
1525 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1526 {
1527         struct nfs_inode *nfsi = NFS_I(inode);
1528         int flags = FLUSH_SYNC;
1529         int ret = 0;
1530
1531         if (wbc->sync_mode == WB_SYNC_NONE) {
1532                 /* Don't commit yet if this is a non-blocking flush and there
1533                  * are a lot of outstanding writes for this mapping.
1534                  */
1535                 if (nfsi->ncommit <= (nfsi->npages >> 1))
1536                         goto out_mark_dirty;
1537
1538                 /* don't wait for the COMMIT response */
1539                 flags = 0;
1540         }
1541
1542         ret = nfs_commit_inode(inode, flags);
1543         if (ret >= 0) {
1544                 if (wbc->sync_mode == WB_SYNC_NONE) {
1545                         if (ret < wbc->nr_to_write)
1546                                 wbc->nr_to_write -= ret;
1547                         else
1548                                 wbc->nr_to_write = 0;
1549                 }
1550                 return 0;
1551         }
1552 out_mark_dirty:
1553         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1554         return ret;
1555 }
1556 #else
1557 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1558 {
1559         return 0;
1560 }
1561 #endif
1562
1563 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1564 {
1565         int ret;
1566
1567         ret = nfs_commit_unstable_pages(inode, wbc);
1568         if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
1569                 int status;
1570                 bool sync = true;
1571
1572                 if (wbc->sync_mode == WB_SYNC_NONE || wbc->nonblocking ||
1573                     wbc->for_background)
1574                         sync = false;
1575
1576                 status = pnfs_layoutcommit_inode(inode, sync);
1577                 if (status < 0)
1578                         return status;
1579         }
1580         return ret;
1581 }
1582
1583 /*
1584  * flush the inode to disk.
1585  */
1586 int nfs_wb_all(struct inode *inode)
1587 {
1588         struct writeback_control wbc = {
1589                 .sync_mode = WB_SYNC_ALL,
1590                 .nr_to_write = LONG_MAX,
1591                 .range_start = 0,
1592                 .range_end = LLONG_MAX,
1593         };
1594
1595         return sync_inode(inode, &wbc);
1596 }
1597
1598 int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1599 {
1600         struct nfs_page *req;
1601         int ret = 0;
1602
1603         BUG_ON(!PageLocked(page));
1604         for (;;) {
1605                 wait_on_page_writeback(page);
1606                 req = nfs_page_find_request(page);
1607                 if (req == NULL)
1608                         break;
1609                 if (nfs_lock_request_dontget(req)) {
1610                         nfs_inode_remove_request(req);
1611                         /*
1612                          * In case nfs_inode_remove_request has marked the
1613                          * page as being dirty
1614                          */
1615                         cancel_dirty_page(page, PAGE_CACHE_SIZE);
1616                         nfs_unlock_request(req);
1617                         break;
1618                 }
1619                 ret = nfs_wait_on_request(req);
1620                 nfs_release_request(req);
1621                 if (ret < 0)
1622                         break;
1623         }
1624         return ret;
1625 }
1626
1627 /*
1628  * Write back all requests on one page - we do this before reading it.
1629  */
1630 int nfs_wb_page(struct inode *inode, struct page *page)
1631 {
1632         loff_t range_start = page_offset(page);
1633         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1634         struct writeback_control wbc = {
1635                 .sync_mode = WB_SYNC_ALL,
1636                 .nr_to_write = 0,
1637                 .range_start = range_start,
1638                 .range_end = range_end,
1639         };
1640         int ret;
1641
1642         for (;;) {
1643                 wait_on_page_writeback(page);
1644                 if (clear_page_dirty_for_io(page)) {
1645                         ret = nfs_writepage_locked(page, &wbc);
1646                         if (ret < 0)
1647                                 goto out_error;
1648                         continue;
1649                 }
1650                 if (!PagePrivate(page))
1651                         break;
1652                 ret = nfs_commit_inode(inode, FLUSH_SYNC);
1653                 if (ret < 0)
1654                         goto out_error;
1655         }
1656         return 0;
1657 out_error:
1658         return ret;
1659 }
1660
1661 #ifdef CONFIG_MIGRATION
1662 int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
1663                 struct page *page)
1664 {
1665         struct nfs_page *req;
1666         int ret;
1667
1668         nfs_fscache_release_page(page, GFP_KERNEL);
1669
1670         req = nfs_find_and_lock_request(page, false);
1671         ret = PTR_ERR(req);
1672         if (IS_ERR(req))
1673                 goto out;
1674
1675         ret = migrate_page(mapping, newpage, page);
1676         if (!req)
1677                 goto out;
1678         if (ret)
1679                 goto out_unlock;
1680         page_cache_get(newpage);
1681         spin_lock(&mapping->host->i_lock);
1682         req->wb_page = newpage;
1683         SetPagePrivate(newpage);
1684         set_page_private(newpage, (unsigned long)req);
1685         ClearPagePrivate(page);
1686         set_page_private(page, 0);
1687         spin_unlock(&mapping->host->i_lock);
1688         page_cache_release(page);
1689 out_unlock:
1690         nfs_clear_page_tag_locked(req);
1691 out:
1692         return ret;
1693 }
1694 #endif
1695
1696 int __init nfs_init_writepagecache(void)
1697 {
1698         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1699                                              sizeof(struct nfs_write_data),
1700                                              0, SLAB_HWCACHE_ALIGN,
1701                                              NULL);
1702         if (nfs_wdata_cachep == NULL)
1703                 return -ENOMEM;
1704
1705         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1706                                                      nfs_wdata_cachep);
1707         if (nfs_wdata_mempool == NULL)
1708                 return -ENOMEM;
1709
1710         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1711                                                       nfs_wdata_cachep);
1712         if (nfs_commit_mempool == NULL)
1713                 return -ENOMEM;
1714
1715         /*
1716          * NFS congestion size, scale with available memory.
1717          *
1718          *  64MB:    8192k
1719          * 128MB:   11585k
1720          * 256MB:   16384k
1721          * 512MB:   23170k
1722          *   1GB:   32768k
1723          *   2GB:   46340k
1724          *   4GB:   65536k
1725          *   8GB:   92681k
1726          *  16GB:  131072k
1727          *
1728          * This allows larger machines to have larger/more transfers.
1729          * Limit the default to 256M
1730          */
1731         nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1732         if (nfs_congestion_kb > 256*1024)
1733                 nfs_congestion_kb = 256*1024;
1734
1735         return 0;
1736 }
1737
1738 void nfs_destroy_writepagecache(void)
1739 {
1740         mempool_destroy(nfs_commit_mempool);
1741         mempool_destroy(nfs_wdata_mempool);
1742         kmem_cache_destroy(nfs_wdata_cachep);
1743 }
1744