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
  17 #include <linux/sunrpc/clnt.h>
  18 #include <linux/nfs_fs.h>
  19 #include <linux/nfs_mount.h>
  20 #include <linux/nfs_page.h>
  21 #include <linux/backing-dev.h>
  22
  23 #include <asm/uaccess.h>
  24
  25 #include "delegation.h"
  26 #include "internal.h"
  27 #include "iostat.h"
  28 #include "nfs4_fs.h"
  29
  30 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  31
  32 #define MIN_POOL_WRITE          (32)
  33 #define MIN_POOL_COMMIT         (4)
  34
  35 /*
  36  * Local function declarations
  37  */
  38 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *desc,
  39                                   struct inode *inode, int ioflags);
  40 static void nfs_redirty_request(struct nfs_page *req);
  41 static const struct rpc_call_ops nfs_write_partial_ops;
  42 static const struct rpc_call_ops nfs_write_full_ops;
  43 static const struct rpc_call_ops nfs_commit_ops;
  44
  45 static struct kmem_cache *nfs_wdata_cachep;
  46 static mempool_t *nfs_wdata_mempool;
  47 static mempool_t *nfs_commit_mempool;
  48
  49 struct nfs_write_data *nfs_commitdata_alloc(void)
  50 {
  51         struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
  52
  53         if (p) {
  54                 memset(p, 0, sizeof(*p));
  55                 INIT_LIST_HEAD(&p->pages);
  56                 p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
  57         }
  58         return p;
  59 }
  60
  61 void nfs_commit_free(struct nfs_write_data *p)
  62 {
  63         if (p && (p->pagevec != &p->page_array[0]))
  64                 kfree(p->pagevec);
  65         mempool_free(p, nfs_commit_mempool);
  66 }
  67
  68 struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
  69 {
  70         struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
  71
  72         if (p) {
  73                 memset(p, 0, sizeof(*p));
  74                 INIT_LIST_HEAD(&p->pages);
  75                 p->npages = pagecount;
  76                 p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
  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)
 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                 if (atomic_long_inc_return(&nfss->writeback) >
 203                                 NFS_CONGESTION_ON_THRESH) {
 204                         set_bdi_congested(&nfss->backing_dev_info,
 205                                                 BLK_RW_ASYNC);
 206                 }
 207         }
 208         return ret;
 209 }
 210
 211 static void nfs_end_page_writeback(struct page *page)
 212 {
 213         struct inode *inode = page->mapping->host;
 214         struct nfs_server *nfss = NFS_SERVER(inode);
 215
 216         end_page_writeback(page);
 217         if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 218                 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
 219 }
 220
 221 /*
 222  * Find an associated nfs write request, and prepare to flush it out
 223  * May return an error if the user signalled nfs_wait_on_request().
 224  */
 225 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 226                                 struct page *page)
 227 {
 228         struct inode *inode = page->mapping->host;
 229         struct nfs_page *req;
 230         int ret;
 231
 232         spin_lock(&inode->i_lock);
 233         for(;;) {
 234                 req = nfs_page_find_request_locked(page);
 235                 if (req == NULL) {
 236                         spin_unlock(&inode->i_lock);
 237                         return 0;
 238                 }
 239                 if (nfs_set_page_tag_locked(req))
 240                         break;
 241                 /* Note: If we hold the page lock, as is the case in nfs_writepage,
 242                  *       then the call to nfs_set_page_tag_locked() will always
 243                  *       succeed provided that someone hasn't already marked the
 244                  *       request as dirty (in which case we don't care).
 245                  */
 246                 spin_unlock(&inode->i_lock);
 247                 ret = nfs_wait_on_request(req);
 248                 nfs_release_request(req);
 249                 if (ret != 0)
 250                         return ret;
 251                 spin_lock(&inode->i_lock);
 252         }
 253         if (test_bit(PG_CLEAN, &req->wb_flags)) {
 254                 spin_unlock(&inode->i_lock);
 255                 BUG();
 256         }
 257         if (nfs_set_page_writeback(page) != 0) {
 258                 spin_unlock(&inode->i_lock);
 259                 BUG();
 260         }
 261         spin_unlock(&inode->i_lock);
 262         if (!nfs_pageio_add_request(pgio, req)) {
 263                 nfs_redirty_request(req);
 264                 return pgio->pg_error;
 265         }
 266         return 0;
 267 }
 268
 269 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
 270 {
 271         struct inode *inode = page->mapping->host;
 272
 273         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 274         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 275
 276         nfs_pageio_cond_complete(pgio, page->index);
 277         return nfs_page_async_flush(pgio, page);
 278 }
 279
 280 /*
 281  * Write an mmapped page to the server.
 282  */
 283 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 284 {
 285         struct nfs_pageio_descriptor pgio;
 286         int err;
 287
 288         nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc));
 289         err = nfs_do_writepage(page, wbc, &pgio);
 290         nfs_pageio_complete(&pgio);
 291         if (err < 0)
 292                 return err;
 293         if (pgio.pg_error < 0)
 294                 return pgio.pg_error;
 295         return 0;
 296 }
 297
 298 int nfs_writepage(struct page *page, struct writeback_control *wbc)
 299 {
 300         int ret;
 301
 302         ret = nfs_writepage_locked(page, wbc);
 303         unlock_page(page);
 304         return ret;
 305 }
 306
 307 static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
 308 {
 309         int ret;
 310
 311         ret = nfs_do_writepage(page, wbc, data);
 312         unlock_page(page);
 313         return ret;
 314 }
 315
 316 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 317 {
 318         struct inode *inode = mapping->host;
 319         unsigned long *bitlock = &NFS_I(inode)->flags;
 320         struct nfs_pageio_descriptor pgio;
 321         int err;
 322
 323         /* Stop dirtying of new pages while we sync */
 324         err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
 325                         nfs_wait_bit_killable, TASK_KILLABLE);
 326         if (err)
 327                 goto out_err;
 328
 329         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 330
 331         nfs_pageio_init_write(&pgio, inode, wb_priority(wbc));
 332         err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
 333         nfs_pageio_complete(&pgio);
 334
 335         clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
 336         smp_mb__after_clear_bit();
 337         wake_up_bit(bitlock, NFS_INO_FLUSHING);
 338
 339         if (err < 0)
 340                 goto out_err;
 341         err = pgio.pg_error;
 342         if (err < 0)
 343                 goto out_err;
 344         return 0;
 345 out_err:
 346         return err;
 347 }
 348
 349 /*
 350  * Insert a write request into an inode
 351  */
 352 static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 353 {
 354         struct nfs_inode *nfsi = NFS_I(inode);
 355         int error;
 356
 357         error = radix_tree_preload(GFP_NOFS);
 358         if (error != 0)
 359                 goto out;
 360
 361         /* Lock the request! */
 362         nfs_lock_request_dontget(req);
 363
 364         spin_lock(&inode->i_lock);
 365         error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
 366         BUG_ON(error);
 367         if (!nfsi->npages) {
 368                 igrab(inode);
 369                 if (nfs_have_delegation(inode, FMODE_WRITE))
 370                         nfsi->change_attr++;
 371         }
 372         SetPagePrivate(req->wb_page);
 373         set_page_private(req->wb_page, (unsigned long)req);
 374         nfsi->npages++;
 375         kref_get(&req->wb_kref);
 376         radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
 377                                 NFS_PAGE_TAG_LOCKED);
 378         spin_unlock(&inode->i_lock);
 379         radix_tree_preload_end();
 380 out:
 381         return error;
 382 }
 383
 384 /*
 385  * Remove a write request from an inode
 386  */
 387 static void nfs_inode_remove_request(struct nfs_page *req)
 388 {
 389         struct inode *inode = req->wb_context->path.dentry->d_inode;
 390         struct nfs_inode *nfsi = NFS_I(inode);
 391
 392         BUG_ON (!NFS_WBACK_BUSY(req));
 393
 394         spin_lock(&inode->i_lock);
 395         set_page_private(req->wb_page, 0);
 396         ClearPagePrivate(req->wb_page);
 397         radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
 398         nfsi->npages--;
 399         if (!nfsi->npages) {
 400                 spin_unlock(&inode->i_lock);
 401                 iput(inode);
 402         } else
 403                 spin_unlock(&inode->i_lock);
 404         nfs_clear_request(req);
 405         nfs_release_request(req);
 406 }
 407
 408 static void
 409 nfs_mark_request_dirty(struct nfs_page *req)
 410 {
 411         __set_page_dirty_nobuffers(req->wb_page);
 412 }
 413
 414 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 415 /*
 416  * Add a request to the inode's commit list.
 417  */
 418 static void
 419 nfs_mark_request_commit(struct nfs_page *req)
 420 {
 421         struct inode *inode = req->wb_context->path.dentry->d_inode;
 422         struct nfs_inode *nfsi = NFS_I(inode);
 423
 424         spin_lock(&inode->i_lock);
 425         set_bit(PG_CLEAN, &(req)->wb_flags);
 426         radix_tree_tag_set(&nfsi->nfs_page_tree,
 427                         req->wb_index,
 428                         NFS_PAGE_TAG_COMMIT);
 429         spin_unlock(&inode->i_lock);
 430         inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 431         inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 432         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 433 }
 434
 435 static int
 436 nfs_clear_request_commit(struct nfs_page *req)
 437 {
 438         struct page *page = req->wb_page;
 439
 440         if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
 441                 dec_zone_page_state(page, NR_UNSTABLE_NFS);
 442                 dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 443                 return 1;
 444         }
 445         return 0;
 446 }
 447
 448 static inline
 449 int nfs_write_need_commit(struct nfs_write_data *data)
 450 {
 451         return data->verf.committed != NFS_FILE_SYNC;
 452 }
 453
 454 static inline
 455 int nfs_reschedule_unstable_write(struct nfs_page *req)
 456 {
 457         if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {
 458                 nfs_mark_request_commit(req);
 459                 return 1;
 460         }
 461         if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
 462                 nfs_mark_request_dirty(req);
 463                 return 1;
 464         }
 465         return 0;
 466 }
 467 #else
 468 static inline void
 469 nfs_mark_request_commit(struct nfs_page *req)
 470 {
 471 }
 472
 473 static inline int
 474 nfs_clear_request_commit(struct nfs_page *req)
 475 {
 476         return 0;
 477 }
 478
 479 static inline
 480 int nfs_write_need_commit(struct nfs_write_data *data)
 481 {
 482         return 0;
 483 }
 484
 485 static inline
 486 int nfs_reschedule_unstable_write(struct nfs_page *req)
 487 {
 488         return 0;
 489 }
 490 #endif
 491
 492 /*
 493  * Wait for a request to complete.
 494  *
 495  * Interruptible by fatal signals only.
 496  */
 497 static int nfs_wait_on_requests_locked(struct inode *inode, pgoff_t idx_start, unsigned int npages)
 498 {
 499         struct nfs_inode *nfsi = NFS_I(inode);
 500         struct nfs_page *req;
 501         pgoff_t idx_end, next;
 502         unsigned int            res = 0;
 503         int                     error;
 504
 505         if (npages == 0)
 506                 idx_end = ~0;
 507         else
 508                 idx_end = idx_start + npages - 1;
 509
 510         next = idx_start;
 511         while (radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, (void **)&req, next, 1, NFS_PAGE_TAG_LOCKED)) {
 512                 if (req->wb_index > idx_end)
 513                         break;
 514
 515                 next = req->wb_index + 1;
 516                 BUG_ON(!NFS_WBACK_BUSY(req));
 517
 518                 kref_get(&req->wb_kref);
 519                 spin_unlock(&inode->i_lock);
 520                 error = nfs_wait_on_request(req);
 521                 nfs_release_request(req);
 522                 spin_lock(&inode->i_lock);
 523                 if (error < 0)
 524                         return error;
 525                 res++;
 526         }
 527         return res;
 528 }
 529
 530 static void nfs_cancel_commit_list(struct list_head *head)
 531 {
 532         struct nfs_page *req;
 533
 534         while(!list_empty(head)) {
 535                 req = nfs_list_entry(head->next);
 536                 nfs_list_remove_request(req);
 537                 nfs_clear_request_commit(req);
 538                 nfs_inode_remove_request(req);
 539                 nfs_unlock_request(req);
 540         }
 541 }
 542
 543 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 544 static int
 545 nfs_need_commit(struct nfs_inode *nfsi)
 546 {
 547         return radix_tree_tagged(&nfsi->nfs_page_tree, NFS_PAGE_TAG_COMMIT);
 548 }
 549
 550 /*
 551  * nfs_scan_commit - Scan an inode for commit requests
 552  * @inode: NFS inode to scan
 553  * @dst: destination list
 554  * @idx_start: lower bound of page->index to scan.
 555  * @npages: idx_start + npages sets the upper bound to scan.
 556  *
 557  * Moves requests from the inode's 'commit' request list.
 558  * The requests are *not* checked to ensure that they form a contiguous set.
 559  */
 560 static int
 561 nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 562 {
 563         struct nfs_inode *nfsi = NFS_I(inode);
 564
 565         if (!nfs_need_commit(nfsi))
 566                 return 0;
 567
 568         return nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
 569 }
 570 #else
 571 static inline int nfs_need_commit(struct nfs_inode *nfsi)
 572 {
 573         return 0;
 574 }
 575
 576 static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 577 {
 578         return 0;
 579 }
 580 #endif
 581
 582 /*
 583  * Search for an existing write request, and attempt to update
 584  * it to reflect a new dirty region on a given page.
 585  *
 586  * If the attempt fails, then the existing request is flushed out
 587  * to disk.
 588  */
 589 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
 590                 struct page *page,
 591                 unsigned int offset,
 592                 unsigned int bytes)
 593 {
 594         struct nfs_page *req;
 595         unsigned int rqend;
 596         unsigned int end;
 597         int error;
 598
 599         if (!PagePrivate(page))
 600                 return NULL;
 601
 602         end = offset + bytes;
 603         spin_lock(&inode->i_lock);
 604
 605         for (;;) {
 606                 req = nfs_page_find_request_locked(page);
 607                 if (req == NULL)
 608                         goto out_unlock;
 609
 610                 rqend = req->wb_offset + req->wb_bytes;
 611                 /*
 612                  * Tell the caller to flush out the request if
 613                  * the offsets are non-contiguous.
 614                  * Note: nfs_flush_incompatible() will already
 615                  * have flushed out requests having wrong owners.
 616                  */
 617                 if (offset > rqend
 618                     || end < req->wb_offset)
 619                         goto out_flushme;
 620
 621                 if (nfs_set_page_tag_locked(req))
 622                         break;
 623
 624                 /* The request is locked, so wait and then retry */
 625                 spin_unlock(&inode->i_lock);
 626                 error = nfs_wait_on_request(req);
 627                 nfs_release_request(req);
 628                 if (error != 0)
 629                         goto out_err;
 630                 spin_lock(&inode->i_lock);
 631         }
 632
 633         if (nfs_clear_request_commit(req))
 634                 radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
 635                                 req->wb_index, NFS_PAGE_TAG_COMMIT);
 636
 637         /* Okay, the request matches. Update the region */
 638         if (offset < req->wb_offset) {
 639                 req->wb_offset = offset;
 640                 req->wb_pgbase = offset;
 641         }
 642         if (end > rqend)
 643                 req->wb_bytes = end - req->wb_offset;
 644         else
 645                 req->wb_bytes = rqend - req->wb_offset;
 646 out_unlock:
 647         spin_unlock(&inode->i_lock);
 648         return req;
 649 out_flushme:
 650         spin_unlock(&inode->i_lock);
 651         nfs_release_request(req);
 652         error = nfs_wb_page(inode, page);
 653 out_err:
 654         return ERR_PTR(error);
 655 }
 656
 657 /*
 658  * Try to update an existing write request, or create one if there is none.
 659  *
 660  * Note: Should always be called with the Page Lock held to prevent races
 661  * if we have to add a new request. Also assumes that the caller has
 662  * already called nfs_flush_incompatible() if necessary.
 663  */
 664 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
 665                 struct page *page, unsigned int offset, unsigned int bytes)
 666 {
 667         struct inode *inode = page->mapping->host;
 668         struct nfs_page *req;
 669         int error;
 670
 671         req = nfs_try_to_update_request(inode, page, offset, bytes);
 672         if (req != NULL)
 673                 goto out;
 674         req = nfs_create_request(ctx, inode, page, offset, bytes);
 675         if (IS_ERR(req))
 676                 goto out;
 677         error = nfs_inode_add_request(inode, req);
 678         if (error != 0) {
 679                 nfs_release_request(req);
 680                 req = ERR_PTR(error);
 681         }
 682 out:
 683         return req;
 684 }
 685
 686 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 687                 unsigned int offset, unsigned int count)
 688 {
 689         struct nfs_page *req;
 690
 691         req = nfs_setup_write_request(ctx, page, offset, count);
 692         if (IS_ERR(req))
 693                 return PTR_ERR(req);
 694         /* Update file length */
 695         nfs_grow_file(page, offset, count);
 696         nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
 697         nfs_clear_page_tag_locked(req);
 698         return 0;
 699 }
 700
 701 int nfs_flush_incompatible(struct file *file, struct page *page)
 702 {
 703         struct nfs_open_context *ctx = nfs_file_open_context(file);
 704         struct nfs_page *req;
 705         int do_flush, status;
 706         /*
 707          * Look for a request corresponding to this page. If there
 708          * is one, and it belongs to another file, we flush it out
 709          * before we try to copy anything into the page. Do this
 710          * due to the lack of an ACCESS-type call in NFSv2.
 711          * Also do the same if we find a request from an existing
 712          * dropped page.
 713          */
 714         do {
 715                 req = nfs_page_find_request(page);
 716                 if (req == NULL)
 717                         return 0;
 718                 do_flush = req->wb_page != page || req->wb_context != ctx;
 719                 nfs_release_request(req);
 720                 if (!do_flush)
 721                         return 0;
 722                 status = nfs_wb_page(page->mapping->host, page);
 723         } while (status == 0);
 724         return status;
 725 }
 726
 727 /*
 728  * If the page cache is marked as unsafe or invalid, then we can't rely on
 729  * the PageUptodate() flag. In this case, we will need to turn off
 730  * write optimisations that depend on the page contents being correct.
 731  */
 732 static int nfs_write_pageuptodate(struct page *page, struct inode *inode)
 733 {
 734         return PageUptodate(page) &&
 735                 !(NFS_I(inode)->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA));
 736 }
 737
 738 /*
 739  * Update and possibly write a cached page of an NFS file.
 740  *
 741  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
 742  * things with a page scheduled for an RPC call (e.g. invalidate it).
 743  */
 744 int nfs_updatepage(struct file *file, struct page *page,
 745                 unsigned int offset, unsigned int count)
 746 {
 747         struct nfs_open_context *ctx = nfs_file_open_context(file);
 748         struct inode    *inode = page->mapping->host;
 749         int             status = 0;
 750
 751         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 752
 753         dprintk("NFS:       nfs_updatepage(%s/%s %d@%lld)\n",
 754                 file->f_path.dentry->d_parent->d_name.name,
 755                 file->f_path.dentry->d_name.name, count,
 756                 (long long)(page_offset(page) + offset));
 757
 758         /* If we're not using byte range locks, and we know the page
 759          * is up to date, it may be more efficient to extend the write
 760          * to cover the entire page in order to avoid fragmentation
 761          * inefficiencies.
 762          */
 763         if (nfs_write_pageuptodate(page, inode) &&
 764                         inode->i_flock == NULL &&
 765                         !(file->f_flags & O_SYNC)) {
 766                 count = max(count + offset, nfs_page_length(page));
 767                 offset = 0;
 768         }
 769
 770         status = nfs_writepage_setup(ctx, page, offset, count);
 771         if (status < 0)
 772                 nfs_set_pageerror(page);
 773         else
 774                 __set_page_dirty_nobuffers(page);
 775
 776         dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
 777                         status, (long long)i_size_read(inode));
 778         return status;
 779 }
 780
 781 static void nfs_writepage_release(struct nfs_page *req)
 782 {
 783
 784         if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req)) {
 785                 nfs_end_page_writeback(req->wb_page);
 786                 nfs_inode_remove_request(req);
 787         } else
 788                 nfs_end_page_writeback(req->wb_page);
 789         nfs_clear_page_tag_locked(req);
 790 }
 791
 792 static int flush_task_priority(int how)
 793 {
 794         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
 795                 case FLUSH_HIGHPRI:
 796                         return RPC_PRIORITY_HIGH;
 797                 case FLUSH_LOWPRI:
 798                         return RPC_PRIORITY_LOW;
 799         }
 800         return RPC_PRIORITY_NORMAL;
 801 }
 802
 803 /*
 804  * Set up the argument/result storage required for the RPC call.
 805  */
 806 static int nfs_write_rpcsetup(struct nfs_page *req,
 807                 struct nfs_write_data *data,
 808                 const struct rpc_call_ops *call_ops,
 809                 unsigned int count, unsigned int offset,
 810                 int how)
 811 {
 812         struct inode *inode = req->wb_context->path.dentry->d_inode;
 813         int flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
 814         int priority = flush_task_priority(how);
 815         struct rpc_task *task;
 816         struct rpc_message msg = {
 817                 .rpc_argp = &data->args,
 818                 .rpc_resp = &data->res,
 819                 .rpc_cred = req->wb_context->cred,
 820         };
 821         struct rpc_task_setup task_setup_data = {
 822                 .rpc_client = NFS_CLIENT(inode),
 823                 .task = &data->task,
 824                 .rpc_message = &msg,
 825                 .callback_ops = call_ops,
 826                 .callback_data = data,
 827                 .workqueue = nfsiod_workqueue,
 828                 .flags = flags,
 829                 .priority = priority,
 830         };
 831
 832         /* Set up the RPC argument and reply structs
 833          * NB: take care not to mess about with data->commit et al. */
 834
 835         data->req = req;
 836         data->inode = inode = req->wb_context->path.dentry->d_inode;
 837         data->cred = msg.rpc_cred;
 838
 839         data->args.fh     = NFS_FH(inode);
 840         data->args.offset = req_offset(req) + offset;
 841         data->args.pgbase = req->wb_pgbase + offset;
 842         data->args.pages  = data->pagevec;
 843         data->args.count  = count;
 844         data->args.context = get_nfs_open_context(req->wb_context);
 845         data->args.stable  = NFS_UNSTABLE;
 846         if (how & FLUSH_STABLE) {
 847                 data->args.stable = NFS_DATA_SYNC;
 848                 if (!nfs_need_commit(NFS_I(inode)))
 849                         data->args.stable = NFS_FILE_SYNC;
 850         }
 851
 852         data->res.fattr   = &data->fattr;
 853         data->res.count   = count;
 854         data->res.verf    = &data->verf;
 855         nfs_fattr_init(&data->fattr);
 856
 857         /* Set up the initial task struct.  */
 858         NFS_PROTO(inode)->write_setup(data, &msg);
 859
 860         dprintk("NFS: %5u initiated write call "
 861                 "(req %s/%lld, %u bytes @ offset %llu)\n",
 862                 data->task.tk_pid,
 863                 inode->i_sb->s_id,
 864                 (long long)NFS_FILEID(inode),
 865                 count,
 866                 (unsigned long long)data->args.offset);
 867
 868         task = rpc_run_task(&task_setup_data);
 869         if (IS_ERR(task))
 870                 return PTR_ERR(task);
 871         rpc_put_task(task);
 872         return 0;
 873 }
 874
 875 /* If a nfs_flush_* function fails, it should remove reqs from @head and
 876  * call this on each, which will prepare them to be retried on next
 877  * writeback using standard nfs.
 878  */
 879 static void nfs_redirty_request(struct nfs_page *req)
 880 {
 881         nfs_mark_request_dirty(req);
 882         nfs_end_page_writeback(req->wb_page);
 883         nfs_clear_page_tag_locked(req);
 884 }
 885
 886 /*
 887  * Generate multiple small requests to write out a single
 888  * contiguous dirty area on one page.
 889  */
 890 static int nfs_flush_multi(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int how)
 891 {
 892         struct nfs_page *req = nfs_list_entry(head->next);
 893         struct page *page = req->wb_page;
 894         struct nfs_write_data *data;
 895         size_t wsize = NFS_SERVER(inode)->wsize, nbytes;
 896         unsigned int offset;
 897         int requests = 0;
 898         int ret = 0;
 899         LIST_HEAD(list);
 900
 901         nfs_list_remove_request(req);
 902
 903         nbytes = count;
 904         do {
 905                 size_t len = min(nbytes, wsize);
 906
 907                 data = nfs_writedata_alloc(1);
 908                 if (!data)
 909                         goto out_bad;
 910                 list_add(&data->pages, &list);
 911                 requests++;
 912                 nbytes -= len;
 913         } while (nbytes != 0);
 914         atomic_set(&req->wb_complete, requests);
 915
 916         ClearPageError(page);
 917         offset = 0;
 918         nbytes = count;
 919         do {
 920                 int ret2;
 921
 922                 data = list_entry(list.next, struct nfs_write_data, pages);
 923                 list_del_init(&data->pages);
 924
 925                 data->pagevec[0] = page;
 926
 927                 if (nbytes < wsize)
 928                         wsize = nbytes;
 929                 ret2 = nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
 930                                    wsize, offset, how);
 931                 if (ret == 0)
 932                         ret = ret2;
 933                 offset += wsize;
 934                 nbytes -= wsize;
 935         } while (nbytes != 0);
 936
 937         return ret;
 938
 939 out_bad:
 940         while (!list_empty(&list)) {
 941                 data = list_entry(list.next, struct nfs_write_data, pages);
 942                 list_del(&data->pages);
 943                 nfs_writedata_release(data);
 944         }
 945         nfs_redirty_request(req);
 946         return -ENOMEM;
 947 }
 948
 949 /*
 950  * Create an RPC task for the given write request and kick it.
 951  * The page must have been locked by the caller.
 952  *
 953  * It may happen that the page we're passed is not marked dirty.
 954  * This is the case if nfs_updatepage detects a conflicting request
 955  * that has been written but not committed.
 956  */
 957 static int nfs_flush_one(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int how)
 958 {
 959         struct nfs_page         *req;
 960         struct page             **pages;
 961         struct nfs_write_data   *data;
 962
 963         data = nfs_writedata_alloc(npages);
 964         if (!data)
 965                 goto out_bad;
 966
 967         pages = data->pagevec;
 968         while (!list_empty(head)) {
 969                 req = nfs_list_entry(head->next);
 970                 nfs_list_remove_request(req);
 971                 nfs_list_add_request(req, &data->pages);
 972                 ClearPageError(req->wb_page);
 973                 *pages++ = req->wb_page;
 974         }
 975         req = nfs_list_entry(data->pages.next);
 976
 977         /* Set up the argument struct */
 978         return nfs_write_rpcsetup(req, data, &nfs_write_full_ops, count, 0, how);
 979  out_bad:
 980         while (!list_empty(head)) {
 981                 req = nfs_list_entry(head->next);
 982                 nfs_list_remove_request(req);
 983                 nfs_redirty_request(req);
 984         }
 985         return -ENOMEM;
 986 }
 987
 988 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
 989                                   struct inode *inode, int ioflags)
 990 {
 991         size_t wsize = NFS_SERVER(inode)->wsize;
 992
 993         if (wsize < PAGE_CACHE_SIZE)
 994                 nfs_pageio_init(pgio, inode, nfs_flush_multi, wsize, ioflags);
 995         else
 996                 nfs_pageio_init(pgio, inode, nfs_flush_one, wsize, ioflags);
 997 }
 998
 999 /*
1000  * Handle a write reply that flushed part of a page.
1001  */
1002 static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
1003 {
1004         struct nfs_write_data   *data = calldata;
1005
1006         dprintk("NFS: %5u write(%s/%lld %d@%lld)",
1007                 task->tk_pid,
1008                 data->req->wb_context->path.dentry->d_inode->i_sb->s_id,
1009                 (long long)
1010                   NFS_FILEID(data->req->wb_context->path.dentry->d_inode),
1011                 data->req->wb_bytes, (long long)req_offset(data->req));
1012
1013         nfs_writeback_done(task, data);
1014 }
1015
1016 static void nfs_writeback_release_partial(void *calldata)
1017 {
1018         struct nfs_write_data   *data = calldata;
1019         struct nfs_page         *req = data->req;
1020         struct page             *page = req->wb_page;
1021         int status = data->task.tk_status;
1022
1023         if (status < 0) {
1024                 nfs_set_pageerror(page);
1025                 nfs_context_set_write_error(req->wb_context, status);
1026                 dprintk(", error = %d\n", status);
1027                 goto out;
1028         }
1029
1030         if (nfs_write_need_commit(data)) {
1031                 struct inode *inode = page->mapping->host;
1032
1033                 spin_lock(&inode->i_lock);
1034                 if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
1035                         /* Do nothing we need to resend the writes */
1036                 } else if (!test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) {
1037                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1038                         dprintk(" defer commit\n");
1039                 } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
1040                         set_bit(PG_NEED_RESCHED, &req->wb_flags);
1041                         clear_bit(PG_NEED_COMMIT, &req->wb_flags);
1042                         dprintk(" server reboot detected\n");
1043                 }
1044                 spin_unlock(&inode->i_lock);
1045         } else
1046                 dprintk(" OK\n");
1047
1048 out:
1049         if (atomic_dec_and_test(&req->wb_complete))
1050                 nfs_writepage_release(req);
1051         nfs_writedata_release(calldata);
1052 }
1053
1054 #if defined(CONFIG_NFS_V4_1)
1055 void nfs_write_prepare(struct rpc_task *task, void *calldata)
1056 {
1057         struct nfs_write_data *data = calldata;
1058         struct nfs_client *clp = (NFS_SERVER(data->inode))->nfs_client;
1059
1060         if (nfs4_setup_sequence(clp, &data->args.seq_args,
1061                                 &data->res.seq_res, 1, task))
1062                 return;
1063         rpc_call_start(task);
1064 }
1065 #endif /* CONFIG_NFS_V4_1 */
1066
1067 static const struct rpc_call_ops nfs_write_partial_ops = {
1068 #if defined(CONFIG_NFS_V4_1)
1069         .rpc_call_prepare = nfs_write_prepare,
1070 #endif /* CONFIG_NFS_V4_1 */
1071         .rpc_call_done = nfs_writeback_done_partial,
1072         .rpc_release = nfs_writeback_release_partial,
1073 };
1074
1075 /*
1076  * Handle a write reply that flushes a whole page.
1077  *
1078  * FIXME: There is an inherent race with invalidate_inode_pages and
1079  *        writebacks since the page->count is kept > 1 for as long
1080  *        as the page has a write request pending.
1081  */
1082 static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
1083 {
1084         struct nfs_write_data   *data = calldata;
1085
1086         nfs_writeback_done(task, data);
1087 }
1088
1089 static void nfs_writeback_release_full(void *calldata)
1090 {
1091         struct nfs_write_data   *data = calldata;
1092         int status = data->task.tk_status;
1093
1094         /* Update attributes as result of writeback. */
1095         while (!list_empty(&data->pages)) {
1096                 struct nfs_page *req = nfs_list_entry(data->pages.next);
1097                 struct page *page = req->wb_page;
1098
1099                 nfs_list_remove_request(req);
1100
1101                 dprintk("NFS: %5u write (%s/%lld %d@%lld)",
1102                         data->task.tk_pid,
1103                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1104                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1105                         req->wb_bytes,
1106                         (long long)req_offset(req));
1107
1108                 if (status < 0) {
1109                         nfs_set_pageerror(page);
1110                         nfs_context_set_write_error(req->wb_context, status);
1111                         dprintk(", error = %d\n", status);
1112                         goto remove_request;
1113                 }
1114
1115                 if (nfs_write_need_commit(data)) {
1116                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1117                         nfs_mark_request_commit(req);
1118                         nfs_end_page_writeback(page);
1119                         dprintk(" marked for commit\n");
1120                         goto next;
1121                 }
1122                 dprintk(" OK\n");
1123 remove_request:
1124                 nfs_end_page_writeback(page);
1125                 nfs_inode_remove_request(req);
1126         next:
1127                 nfs_clear_page_tag_locked(req);
1128         }
1129         nfs_writedata_release(calldata);
1130 }
1131
1132 static const struct rpc_call_ops nfs_write_full_ops = {
1133 #if defined(CONFIG_NFS_V4_1)
1134         .rpc_call_prepare = nfs_write_prepare,
1135 #endif /* CONFIG_NFS_V4_1 */
1136         .rpc_call_done = nfs_writeback_done_full,
1137         .rpc_release = nfs_writeback_release_full,
1138 };
1139
1140
1141 /*
1142  * This function is called when the WRITE call is complete.
1143  */
1144 int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1145 {
1146         struct nfs_writeargs    *argp = &data->args;
1147         struct nfs_writeres     *resp = &data->res;
1148         struct nfs_server       *server = NFS_SERVER(data->inode);
1149         int status;
1150
1151         dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1152                 task->tk_pid, task->tk_status);
1153
1154         /*
1155          * ->write_done will attempt to use post-op attributes to detect
1156          * conflicting writes by other clients.  A strict interpretation
1157          * of close-to-open would allow us to continue caching even if
1158          * another writer had changed the file, but some applications
1159          * depend on tighter cache coherency when writing.
1160          */
1161         status = NFS_PROTO(data->inode)->write_done(task, data);
1162         if (status != 0)
1163                 return status;
1164         nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1165
1166 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1167         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1168                 /* We tried a write call, but the server did not
1169                  * commit data to stable storage even though we
1170                  * requested it.
1171                  * Note: There is a known bug in Tru64 < 5.0 in which
1172                  *       the server reports NFS_DATA_SYNC, but performs
1173                  *       NFS_FILE_SYNC. We therefore implement this checking
1174                  *       as a dprintk() in order to avoid filling syslog.
1175                  */
1176                 static unsigned long    complain;
1177
1178                 if (time_before(complain, jiffies)) {
1179                         dprintk("NFS:       faulty NFS server %s:"
1180                                 " (committed = %d) != (stable = %d)\n",
1181                                 server->nfs_client->cl_hostname,
1182                                 resp->verf->committed, argp->stable);
1183                         complain = jiffies + 300 * HZ;
1184                 }
1185         }
1186 #endif
1187         /* Is this a short write? */
1188         if (task->tk_status >= 0 && resp->count < argp->count) {
1189                 static unsigned long    complain;
1190
1191                 nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
1192
1193                 /* Has the server at least made some progress? */
1194                 if (resp->count != 0) {
1195                         /* Was this an NFSv2 write or an NFSv3 stable write? */
1196                         if (resp->verf->committed != NFS_UNSTABLE) {
1197                                 /* Resend from where the server left off */
1198                                 argp->offset += resp->count;
1199                                 argp->pgbase += resp->count;
1200                                 argp->count -= resp->count;
1201                         } else {
1202                                 /* Resend as a stable write in order to avoid
1203                                  * headaches in the case of a server crash.
1204                                  */
1205                                 argp->stable = NFS_FILE_SYNC;
1206                         }
1207                         nfs4_restart_rpc(task, server->nfs_client);
1208                         return -EAGAIN;
1209                 }
1210                 if (time_before(complain, jiffies)) {
1211                         printk(KERN_WARNING
1212                                "NFS: Server wrote zero bytes, expected %u.\n",
1213                                         argp->count);
1214                         complain = jiffies + 300 * HZ;
1215                 }
1216                 /* Can't do anything about it except throw an error. */
1217                 task->tk_status = -EIO;
1218         }
1219         nfs4_sequence_free_slot(server->nfs_client, &data->res.seq_res);
1220         return 0;
1221 }
1222
1223
1224 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1225 void nfs_commitdata_release(void *data)
1226 {
1227         struct nfs_write_data *wdata = data;
1228
1229         put_nfs_open_context(wdata->args.context);
1230         nfs_commit_free(wdata);
1231 }
1232
1233 /*
1234  * Set up the argument/result storage required for the RPC call.
1235  */
1236 static int nfs_commit_rpcsetup(struct list_head *head,
1237                 struct nfs_write_data *data,
1238                 int how)
1239 {
1240         struct nfs_page *first = nfs_list_entry(head->next);
1241         struct inode *inode = first->wb_context->path.dentry->d_inode;
1242         int flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
1243         int priority = flush_task_priority(how);
1244         struct rpc_task *task;
1245         struct rpc_message msg = {
1246                 .rpc_argp = &data->args,
1247                 .rpc_resp = &data->res,
1248                 .rpc_cred = first->wb_context->cred,
1249         };
1250         struct rpc_task_setup task_setup_data = {
1251                 .task = &data->task,
1252                 .rpc_client = NFS_CLIENT(inode),
1253                 .rpc_message = &msg,
1254                 .callback_ops = &nfs_commit_ops,
1255                 .callback_data = data,
1256                 .workqueue = nfsiod_workqueue,
1257                 .flags = flags,
1258                 .priority = priority,
1259         };
1260
1261         /* Set up the RPC argument and reply structs
1262          * NB: take care not to mess about with data->commit et al. */
1263
1264         list_splice_init(head, &data->pages);
1265
1266         data->inode       = inode;
1267         data->cred        = msg.rpc_cred;
1268
1269         data->args.fh     = NFS_FH(data->inode);
1270         /* Note: we always request a commit of the entire inode */
1271         data->args.offset = 0;
1272         data->args.count  = 0;
1273         data->args.context = get_nfs_open_context(first->wb_context);
1274         data->res.count   = 0;
1275         data->res.fattr   = &data->fattr;
1276         data->res.verf    = &data->verf;
1277         nfs_fattr_init(&data->fattr);
1278
1279         /* Set up the initial task struct.  */
1280         NFS_PROTO(inode)->commit_setup(data, &msg);
1281
1282         dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1283
1284         task = rpc_run_task(&task_setup_data);
1285         if (IS_ERR(task))
1286                 return PTR_ERR(task);
1287         rpc_put_task(task);
1288         return 0;
1289 }
1290
1291 /*
1292  * Commit dirty pages
1293  */
1294 static int
1295 nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1296 {
1297         struct nfs_write_data   *data;
1298         struct nfs_page         *req;
1299
1300         data = nfs_commitdata_alloc();
1301
1302         if (!data)
1303                 goto out_bad;
1304
1305         /* Set up the argument struct */
1306         return nfs_commit_rpcsetup(head, data, how);
1307  out_bad:
1308         while (!list_empty(head)) {
1309                 req = nfs_list_entry(head->next);
1310                 nfs_list_remove_request(req);
1311                 nfs_mark_request_commit(req);
1312                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1313                 dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
1314                                 BDI_RECLAIMABLE);
1315                 nfs_clear_page_tag_locked(req);
1316         }
1317         return -ENOMEM;
1318 }
1319
1320 /*
1321  * COMMIT call returned
1322  */
1323 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1324 {
1325         struct nfs_write_data   *data = calldata;
1326
1327         dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1328                                 task->tk_pid, task->tk_status);
1329
1330         /* Call the NFS version-specific code */
1331         if (NFS_PROTO(data->inode)->commit_done(task, data) != 0)
1332                 return;
1333 }
1334
1335 static void nfs_commit_release(void *calldata)
1336 {
1337         struct nfs_write_data   *data = calldata;
1338         struct nfs_page         *req;
1339         int status = data->task.tk_status;
1340
1341         while (!list_empty(&data->pages)) {
1342                 req = nfs_list_entry(data->pages.next);
1343                 nfs_list_remove_request(req);
1344                 nfs_clear_request_commit(req);
1345
1346                 dprintk("NFS:       commit (%s/%lld %d@%lld)",
1347                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1348                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1349                         req->wb_bytes,
1350                         (long long)req_offset(req));
1351                 if (status < 0) {
1352                         nfs_context_set_write_error(req->wb_context, status);
1353                         nfs_inode_remove_request(req);
1354                         dprintk(", error = %d\n", status);
1355                         goto next;
1356                 }
1357
1358                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1359                  * returned by the server against all stored verfs. */
1360                 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1361                         /* We have a match */
1362                         nfs_inode_remove_request(req);
1363                         dprintk(" OK\n");
1364                         goto next;
1365                 }
1366                 /* We have a mismatch. Write the page again */
1367                 dprintk(" mismatch\n");
1368                 nfs_mark_request_dirty(req);
1369         next:
1370                 nfs_clear_page_tag_locked(req);
1371         }
1372         nfs_commitdata_release(calldata);
1373 }
1374
1375 static const struct rpc_call_ops nfs_commit_ops = {
1376 #if defined(CONFIG_NFS_V4_1)
1377         .rpc_call_prepare = nfs_write_prepare,
1378 #endif /* CONFIG_NFS_V4_1 */
1379         .rpc_call_done = nfs_commit_done,
1380         .rpc_release = nfs_commit_release,
1381 };
1382
1383 int nfs_commit_inode(struct inode *inode, int how)
1384 {
1385         LIST_HEAD(head);
1386         int res;
1387
1388         spin_lock(&inode->i_lock);
1389         res = nfs_scan_commit(inode, &head, 0, 0);
1390         spin_unlock(&inode->i_lock);
1391         if (res) {
1392                 int error = nfs_commit_list(inode, &head, how);
1393                 if (error < 0)
1394                         return error;
1395         }
1396         return res;
1397 }
1398 #else
1399 static inline int nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1400 {
1401         return 0;
1402 }
1403 #endif
1404
1405 long nfs_sync_mapping_wait(struct address_space *mapping, struct writeback_control *wbc, int how)
1406 {
1407         struct inode *inode = mapping->host;
1408         pgoff_t idx_start, idx_end;
1409         unsigned int npages = 0;
1410         LIST_HEAD(head);
1411         int nocommit = how & FLUSH_NOCOMMIT;
1412         long pages, ret;
1413
1414         /* FIXME */
1415         if (wbc->range_cyclic)
1416                 idx_start = 0;
1417         else {
1418                 idx_start = wbc->range_start >> PAGE_CACHE_SHIFT;
1419                 idx_end = wbc->range_end >> PAGE_CACHE_SHIFT;
1420                 if (idx_end > idx_start) {
1421                         pgoff_t l_npages = 1 + idx_end - idx_start;
1422                         npages = l_npages;
1423                         if (sizeof(npages) != sizeof(l_npages) &&
1424                                         (pgoff_t)npages != l_npages)
1425                                 npages = 0;
1426                 }
1427         }
1428         how &= ~FLUSH_NOCOMMIT;
1429         spin_lock(&inode->i_lock);
1430         do {
1431                 ret = nfs_wait_on_requests_locked(inode, idx_start, npages);
1432                 if (ret != 0)
1433                         continue;
1434                 if (nocommit)
1435                         break;
1436                 pages = nfs_scan_commit(inode, &head, idx_start, npages);
1437                 if (pages == 0)
1438                         break;
1439                 if (how & FLUSH_INVALIDATE) {
1440                         spin_unlock(&inode->i_lock);
1441                         nfs_cancel_commit_list(&head);
1442                         ret = pages;
1443                         spin_lock(&inode->i_lock);
1444                         continue;
1445                 }
1446                 pages += nfs_scan_commit(inode, &head, 0, 0);
1447                 spin_unlock(&inode->i_lock);
1448                 ret = nfs_commit_list(inode, &head, how);
1449                 spin_lock(&inode->i_lock);
1450
1451         } while (ret >= 0);
1452         spin_unlock(&inode->i_lock);
1453         return ret;
1454 }
1455
1456 static int __nfs_write_mapping(struct address_space *mapping, struct writeback_control *wbc, int how)
1457 {
1458         int ret;
1459
1460         ret = nfs_writepages(mapping, wbc);
1461         if (ret < 0)
1462                 goto out;
1463         ret = nfs_sync_mapping_wait(mapping, wbc, how);
1464         if (ret < 0)
1465                 goto out;
1466         return 0;
1467 out:
1468         __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
1469         return ret;
1470 }
1471
1472 /* Two pass sync: first using WB_SYNC_NONE, then WB_SYNC_ALL */
1473 static int nfs_write_mapping(struct address_space *mapping, int how)
1474 {
1475         struct writeback_control wbc = {
1476                 .bdi = mapping->backing_dev_info,
1477                 .sync_mode = WB_SYNC_ALL,
1478                 .nr_to_write = LONG_MAX,
1479                 .range_start = 0,
1480                 .range_end = LLONG_MAX,
1481                 .for_writepages = 1,
1482         };
1483
1484         return __nfs_write_mapping(mapping, &wbc, how);
1485 }
1486
1487 /*
1488  * flush the inode to disk.
1489  */
1490 int nfs_wb_all(struct inode *inode)
1491 {
1492         return nfs_write_mapping(inode->i_mapping, 0);
1493 }
1494
1495 int nfs_wb_nocommit(struct inode *inode)
1496 {
1497         return nfs_write_mapping(inode->i_mapping, FLUSH_NOCOMMIT);
1498 }
1499
1500 int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1501 {
1502         struct nfs_page *req;
1503         loff_t range_start = page_offset(page);
1504         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1505         struct writeback_control wbc = {
1506                 .bdi = page->mapping->backing_dev_info,
1507                 .sync_mode = WB_SYNC_ALL,
1508                 .nr_to_write = LONG_MAX,
1509                 .range_start = range_start,
1510                 .range_end = range_end,
1511         };
1512         int ret = 0;
1513
1514         BUG_ON(!PageLocked(page));
1515         for (;;) {
1516                 req = nfs_page_find_request(page);
1517                 if (req == NULL)
1518                         goto out;
1519                 if (test_bit(PG_CLEAN, &req->wb_flags)) {
1520                         nfs_release_request(req);
1521                         break;
1522                 }
1523                 if (nfs_lock_request_dontget(req)) {
1524                         nfs_inode_remove_request(req);
1525                         /*
1526                          * In case nfs_inode_remove_request has marked the
1527                          * page as being dirty
1528                          */
1529                         cancel_dirty_page(page, PAGE_CACHE_SIZE);
1530                         nfs_unlock_request(req);
1531                         break;
1532                 }
1533                 ret = nfs_wait_on_request(req);
1534                 if (ret < 0)
1535                         goto out;
1536         }
1537         if (!PagePrivate(page))
1538                 return 0;
1539         ret = nfs_sync_mapping_wait(page->mapping, &wbc, FLUSH_INVALIDATE);
1540 out:
1541         return ret;
1542 }
1543
1544 static int nfs_wb_page_priority(struct inode *inode, struct page *page,
1545                                 int how)
1546 {
1547         loff_t range_start = page_offset(page);
1548         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1549         struct writeback_control wbc = {
1550                 .bdi = page->mapping->backing_dev_info,
1551                 .sync_mode = WB_SYNC_ALL,
1552                 .nr_to_write = LONG_MAX,
1553                 .range_start = range_start,
1554                 .range_end = range_end,
1555         };
1556         int ret;
1557
1558         do {
1559                 if (clear_page_dirty_for_io(page)) {
1560                         ret = nfs_writepage_locked(page, &wbc);
1561                         if (ret < 0)
1562                                 goto out_error;
1563                 } else if (!PagePrivate(page))
1564                         break;
1565                 ret = nfs_sync_mapping_wait(page->mapping, &wbc, how);
1566                 if (ret < 0)
1567                         goto out_error;
1568         } while (PagePrivate(page));
1569         return 0;
1570 out_error:
1571         __mark_inode_dirty(inode, I_DIRTY_PAGES);
1572         return ret;
1573 }
1574
1575 /*
1576  * Write back all requests on one page - we do this before reading it.
1577  */
1578 int nfs_wb_page(struct inode *inode, struct page* page)
1579 {
1580         return nfs_wb_page_priority(inode, page, FLUSH_STABLE);
1581 }
1582
1583 int __init nfs_init_writepagecache(void)
1584 {
1585         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1586                                              sizeof(struct nfs_write_data),
1587                                              0, SLAB_HWCACHE_ALIGN,
1588                                              NULL);
1589         if (nfs_wdata_cachep == NULL)
1590                 return -ENOMEM;
1591
1592         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1593                                                      nfs_wdata_cachep);
1594         if (nfs_wdata_mempool == NULL)
1595                 return -ENOMEM;
1596
1597         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1598                                                       nfs_wdata_cachep);
1599         if (nfs_commit_mempool == NULL)
1600                 return -ENOMEM;
1601
1602         /*
1603          * NFS congestion size, scale with available memory.
1604          *
1605          *  64MB:    8192k
1606          * 128MB:   11585k
1607          * 256MB:   16384k
1608          * 512MB:   23170k
1609          *   1GB:   32768k
1610          *   2GB:   46340k
1611          *   4GB:   65536k
1612          *   8GB:   92681k
1613          *  16GB:  131072k
1614          *
1615          * This allows larger machines to have larger/more transfers.
1616          * Limit the default to 256M
1617          */
1618         nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1619         if (nfs_congestion_kb > 256*1024)
1620                 nfs_congestion_kb = 256*1024;
1621
1622         return 0;
1623 }
1624
1625 void nfs_destroy_writepagecache(void)
1626 {
1627         mempool_destroy(nfs_commit_mempool);
1628         mempool_destroy(nfs_wdata_mempool);
1629         kmem_cache_destroy(nfs_wdata_cachep);
1630 }
1631