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 #include <linux/blkdev.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
  31 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  32
  33 #define MIN_POOL_WRITE          (32)
  34 #define MIN_POOL_COMMIT         (4)
  35
  36 /*
  37  * Local function declarations
  38  */
  39 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *desc,
  40                                   struct inode *inode, int ioflags);
  41 static void nfs_redirty_request(struct nfs_page *req);
  42 static const struct rpc_call_ops nfs_write_partial_ops;
  43 static const struct rpc_call_ops nfs_write_full_ops;
  44 static const struct rpc_call_ops nfs_commit_ops;
  45
  46 static struct kmem_cache *nfs_wdata_cachep;
  47 static mempool_t *nfs_wdata_mempool;
  48 static mempool_t *nfs_commit_mempool;
  49
  50 struct nfs_write_data *nfs_commitdata_alloc(void)
  51 {
  52         struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
  53
  54         if (p) {
  55                 memset(p, 0, sizeof(*p));
  56                 INIT_LIST_HEAD(&p->pages);
  57                 p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
  58         }
  59         return p;
  60 }
  61
  62 void nfs_commit_free(struct nfs_write_data *p)
  63 {
  64         if (p && (p->pagevec != &p->page_array[0]))
  65                 kfree(p->pagevec);
  66         mempool_free(p, nfs_commit_mempool);
  67 }
  68
  69 struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
  70 {
  71         struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
  72
  73         if (p) {
  74                 memset(p, 0, sizeof(*p));
  75                 INIT_LIST_HEAD(&p->pages);
  76                 p->npages = pagecount;
  77                 p->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
  78                 if (pagecount <= ARRAY_SIZE(p->page_array))
  79                         p->pagevec = p->page_array;
  80                 else {
  81                         p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
  82                         if (!p->pagevec) {
  83                                 mempool_free(p, nfs_wdata_mempool);
  84                                 p = NULL;
  85                         }
  86                 }
  87         }
  88         return p;
  89 }
  90
  91 static void nfs_writedata_free(struct nfs_write_data *p)
  92 {
  93         if (p && (p->pagevec != &p->page_array[0]))
  94                 kfree(p->pagevec);
  95         mempool_free(p, nfs_wdata_mempool);
  96 }
  97
  98 void nfs_writedata_release(void *data)
  99 {
 100         struct nfs_write_data *wdata = data;
 101
 102         put_nfs_open_context(wdata->args.context);
 103         nfs_writedata_free(wdata);
 104 }
 105
 106 static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
 107 {
 108         ctx->error = error;
 109         smp_wmb();
 110         set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 111 }
 112
 113 static struct nfs_page *nfs_page_find_request_locked(struct page *page)
 114 {
 115         struct nfs_page *req = NULL;
 116
 117         if (PagePrivate(page)) {
 118                 req = (struct nfs_page *)page_private(page);
 119                 if (req != NULL)
 120                         kref_get(&req->wb_kref);
 121         }
 122         return req;
 123 }
 124
 125 static struct nfs_page *nfs_page_find_request(struct page *page)
 126 {
 127         struct inode *inode = page->mapping->host;
 128         struct nfs_page *req = NULL;
 129
 130         spin_lock(&inode->i_lock);
 131         req = nfs_page_find_request_locked(page);
 132         spin_unlock(&inode->i_lock);
 133         return req;
 134 }
 135
 136 /* Adjust the file length if we're writing beyond the end */
 137 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 138 {
 139         struct inode *inode = page->mapping->host;
 140         loff_t end, i_size;
 141         pgoff_t end_index;
 142
 143         spin_lock(&inode->i_lock);
 144         i_size = i_size_read(inode);
 145         end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 146         if (i_size > 0 && page->index < end_index)
 147                 goto out;
 148         end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
 149         if (i_size >= end)
 150                 goto out;
 151         i_size_write(inode, end);
 152         nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 153 out:
 154         spin_unlock(&inode->i_lock);
 155 }
 156
 157 /* A writeback failed: mark the page as bad, and invalidate the page cache */
 158 static void nfs_set_pageerror(struct page *page)
 159 {
 160         SetPageError(page);
 161         nfs_zap_mapping(page->mapping->host, page->mapping);
 162 }
 163
 164 /* We can set the PG_uptodate flag if we see that a write request
 165  * covers the full page.
 166  */
 167 static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
 168 {
 169         if (PageUptodate(page))
 170                 return;
 171         if (base != 0)
 172                 return;
 173         if (count != nfs_page_length(page))
 174                 return;
 175         SetPageUptodate(page);
 176 }
 177
 178 static int wb_priority(struct writeback_control *wbc)
 179 {
 180         if (wbc->for_reclaim)
 181                 return FLUSH_HIGHPRI | FLUSH_STABLE;
 182         if (wbc->for_kupdate)
 183                 return FLUSH_LOWPRI;
 184         return 0;
 185 }
 186
 187 /*
 188  * NFS congestion control
 189  */
 190
 191 int nfs_congestion_kb;
 192
 193 #define NFS_CONGESTION_ON_THRESH        (nfs_congestion_kb >> (PAGE_SHIFT-10))
 194 #define NFS_CONGESTION_OFF_THRESH       \
 195         (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 196
 197 static int nfs_set_page_writeback(struct page *page)
 198 {
 199         int ret = test_set_page_writeback(page);
 200
 201         if (!ret) {
 202                 struct inode *inode = page->mapping->host;
 203                 struct nfs_server *nfss = NFS_SERVER(inode);
 204
 205                 if (atomic_long_inc_return(&nfss->writeback) >
 206                                 NFS_CONGESTION_ON_THRESH) {
 207                         set_bdi_congested(&nfss->backing_dev_info,
 208                                                 BLK_RW_ASYNC);
 209                 }
 210         }
 211         return ret;
 212 }
 213
 214 static void nfs_end_page_writeback(struct page *page)
 215 {
 216         struct inode *inode = page->mapping->host;
 217         struct nfs_server *nfss = NFS_SERVER(inode);
 218
 219         end_page_writeback(page);
 220         if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 221                 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
 222 }
 223
 224 /*
 225  * Find an associated nfs write request, and prepare to flush it out
 226  * May return an error if the user signalled nfs_wait_on_request().
 227  */
 228 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 229                                 struct page *page)
 230 {
 231         struct inode *inode = page->mapping->host;
 232         struct nfs_page *req;
 233         int ret;
 234
 235         spin_lock(&inode->i_lock);
 236         for(;;) {
 237                 req = nfs_page_find_request_locked(page);
 238                 if (req == NULL) {
 239                         spin_unlock(&inode->i_lock);
 240                         return 0;
 241                 }
 242                 if (nfs_set_page_tag_locked(req))
 243                         break;
 244                 /* Note: If we hold the page lock, as is the case in nfs_writepage,
 245                  *       then the call to nfs_set_page_tag_locked() will always
 246                  *       succeed provided that someone hasn't already marked the
 247                  *       request as dirty (in which case we don't care).
 248                  */
 249                 spin_unlock(&inode->i_lock);
 250                 ret = nfs_wait_on_request(req);
 251                 nfs_release_request(req);
 252                 if (ret != 0)
 253                         return ret;
 254                 spin_lock(&inode->i_lock);
 255         }
 256         if (test_bit(PG_CLEAN, &req->wb_flags)) {
 257                 spin_unlock(&inode->i_lock);
 258                 BUG();
 259         }
 260         if (nfs_set_page_writeback(page) != 0) {
 261                 spin_unlock(&inode->i_lock);
 262                 BUG();
 263         }
 264         spin_unlock(&inode->i_lock);
 265         if (!nfs_pageio_add_request(pgio, req)) {
 266                 nfs_redirty_request(req);
 267                 return pgio->pg_error;
 268         }
 269         return 0;
 270 }
 271
 272 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
 273 {
 274         struct inode *inode = page->mapping->host;
 275
 276         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 277         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 278
 279         nfs_pageio_cond_complete(pgio, page->index);
 280         return nfs_page_async_flush(pgio, page);
 281 }
 282
 283 /*
 284  * Write an mmapped page to the server.
 285  */
 286 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 287 {
 288         struct nfs_pageio_descriptor pgio;
 289         int err;
 290
 291         nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc));
 292         err = nfs_do_writepage(page, wbc, &pgio);
 293         nfs_pageio_complete(&pgio);
 294         if (err < 0)
 295                 return err;
 296         if (pgio.pg_error < 0)
 297                 return pgio.pg_error;
 298         return 0;
 299 }
 300
 301 int nfs_writepage(struct page *page, struct writeback_control *wbc)
 302 {
 303         int ret;
 304
 305         ret = nfs_writepage_locked(page, wbc);
 306         unlock_page(page);
 307         return ret;
 308 }
 309
 310 static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
 311 {
 312         int ret;
 313
 314         ret = nfs_do_writepage(page, wbc, data);
 315         unlock_page(page);
 316         return ret;
 317 }
 318
 319 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 320 {
 321         struct inode *inode = mapping->host;
 322         unsigned long *bitlock = &NFS_I(inode)->flags;
 323         struct nfs_pageio_descriptor pgio;
 324         int err;
 325
 326         /* Stop dirtying of new pages while we sync */
 327         err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
 328                         nfs_wait_bit_killable, TASK_KILLABLE);
 329         if (err)
 330                 goto out_err;
 331
 332         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 333
 334         nfs_pageio_init_write(&pgio, inode, wb_priority(wbc));
 335         err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
 336         nfs_pageio_complete(&pgio);
 337
 338         clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
 339         smp_mb__after_clear_bit();
 340         wake_up_bit(bitlock, NFS_INO_FLUSHING);
 341
 342         if (err < 0)
 343                 goto out_err;
 344         err = pgio.pg_error;
 345         if (err < 0)
 346                 goto out_err;
 347         return 0;
 348 out_err:
 349         return err;
 350 }
 351
 352 /*
 353  * Insert a write request into an inode
 354  */
 355 static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 356 {
 357         struct nfs_inode *nfsi = NFS_I(inode);
 358         int error;
 359
 360         error = radix_tree_preload(GFP_NOFS);
 361         if (error != 0)
 362                 goto out;
 363
 364         /* Lock the request! */
 365         nfs_lock_request_dontget(req);
 366
 367         spin_lock(&inode->i_lock);
 368         error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
 369         BUG_ON(error);
 370         if (!nfsi->npages) {
 371                 igrab(inode);
 372                 if (nfs_have_delegation(inode, FMODE_WRITE))
 373                         nfsi->change_attr++;
 374         }
 375         SetPagePrivate(req->wb_page);
 376         set_page_private(req->wb_page, (unsigned long)req);
 377         nfsi->npages++;
 378         kref_get(&req->wb_kref);
 379         radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
 380                                 NFS_PAGE_TAG_LOCKED);
 381         spin_unlock(&inode->i_lock);
 382         radix_tree_preload_end();
 383 out:
 384         return error;
 385 }
 386
 387 /*
 388  * Remove a write request from an inode
 389  */
 390 static void nfs_inode_remove_request(struct nfs_page *req)
 391 {
 392         struct inode *inode = req->wb_context->path.dentry->d_inode;
 393         struct nfs_inode *nfsi = NFS_I(inode);
 394
 395         BUG_ON (!NFS_WBACK_BUSY(req));
 396
 397         spin_lock(&inode->i_lock);
 398         set_page_private(req->wb_page, 0);
 399         ClearPagePrivate(req->wb_page);
 400         radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
 401         nfsi->npages--;
 402         if (!nfsi->npages) {
 403                 spin_unlock(&inode->i_lock);
 404                 iput(inode);
 405         } else
 406                 spin_unlock(&inode->i_lock);
 407         nfs_clear_request(req);
 408         nfs_release_request(req);
 409 }
 410
 411 static void
 412 nfs_mark_request_dirty(struct nfs_page *req)
 413 {
 414         __set_page_dirty_nobuffers(req->wb_page);
 415 }
 416
 417 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 418 /*
 419  * Add a request to the inode's commit list.
 420  */
 421 static void
 422 nfs_mark_request_commit(struct nfs_page *req)
 423 {
 424         struct inode *inode = req->wb_context->path.dentry->d_inode;
 425         struct nfs_inode *nfsi = NFS_I(inode);
 426
 427         spin_lock(&inode->i_lock);
 428         set_bit(PG_CLEAN, &(req)->wb_flags);
 429         radix_tree_tag_set(&nfsi->nfs_page_tree,
 430                         req->wb_index,
 431                         NFS_PAGE_TAG_COMMIT);
 432         spin_unlock(&inode->i_lock);
 433         inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 434         inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 435         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 436 }
 437
 438 static int
 439 nfs_clear_request_commit(struct nfs_page *req)
 440 {
 441         struct page *page = req->wb_page;
 442
 443         if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
 444                 dec_zone_page_state(page, NR_UNSTABLE_NFS);
 445                 dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 446                 return 1;
 447         }
 448         return 0;
 449 }
 450
 451 static inline
 452 int nfs_write_need_commit(struct nfs_write_data *data)
 453 {
 454         return data->verf.committed != NFS_FILE_SYNC;
 455 }
 456
 457 static inline
 458 int nfs_reschedule_unstable_write(struct nfs_page *req)
 459 {
 460         if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {
 461                 nfs_mark_request_commit(req);
 462                 return 1;
 463         }
 464         if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
 465                 nfs_mark_request_dirty(req);
 466                 return 1;
 467         }
 468         return 0;
 469 }
 470 #else
 471 static inline void
 472 nfs_mark_request_commit(struct nfs_page *req)
 473 {
 474 }
 475
 476 static inline int
 477 nfs_clear_request_commit(struct nfs_page *req)
 478 {
 479         return 0;
 480 }
 481
 482 static inline
 483 int nfs_write_need_commit(struct nfs_write_data *data)
 484 {
 485         return 0;
 486 }
 487
 488 static inline
 489 int nfs_reschedule_unstable_write(struct nfs_page *req)
 490 {
 491         return 0;
 492 }
 493 #endif
 494
 495 /*
 496  * Wait for a request to complete.
 497  *
 498  * Interruptible by fatal signals only.
 499  */
 500 static int nfs_wait_on_requests_locked(struct inode *inode, pgoff_t idx_start, unsigned int npages)
 501 {
 502         struct nfs_inode *nfsi = NFS_I(inode);
 503         struct nfs_page *req;
 504         pgoff_t idx_end, next;
 505         unsigned int            res = 0;
 506         int                     error;
 507
 508         if (npages == 0)
 509                 idx_end = ~0;
 510         else
 511                 idx_end = idx_start + npages - 1;
 512
 513         next = idx_start;
 514         while (radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, (void **)&req, next, 1, NFS_PAGE_TAG_LOCKED)) {
 515                 if (req->wb_index > idx_end)
 516                         break;
 517
 518                 next = req->wb_index + 1;
 519                 BUG_ON(!NFS_WBACK_BUSY(req));
 520
 521                 kref_get(&req->wb_kref);
 522                 spin_unlock(&inode->i_lock);
 523                 error = nfs_wait_on_request(req);
 524                 nfs_release_request(req);
 525                 spin_lock(&inode->i_lock);
 526                 if (error < 0)
 527                         return error;
 528                 res++;
 529         }
 530         return res;
 531 }
 532
 533 static void nfs_cancel_commit_list(struct list_head *head)
 534 {
 535         struct nfs_page *req;
 536
 537         while(!list_empty(head)) {
 538                 req = nfs_list_entry(head->next);
 539                 nfs_list_remove_request(req);
 540                 nfs_clear_request_commit(req);
 541                 nfs_inode_remove_request(req);
 542                 nfs_unlock_request(req);
 543         }
 544 }
 545
 546 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 547 static int
 548 nfs_need_commit(struct nfs_inode *nfsi)
 549 {
 550         return radix_tree_tagged(&nfsi->nfs_page_tree, NFS_PAGE_TAG_COMMIT);
 551 }
 552
 553 /*
 554  * nfs_scan_commit - Scan an inode for commit requests
 555  * @inode: NFS inode to scan
 556  * @dst: destination list
 557  * @idx_start: lower bound of page->index to scan.
 558  * @npages: idx_start + npages sets the upper bound to scan.
 559  *
 560  * Moves requests from the inode's 'commit' request list.
 561  * The requests are *not* checked to ensure that they form a contiguous set.
 562  */
 563 static int
 564 nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 565 {
 566         struct nfs_inode *nfsi = NFS_I(inode);
 567
 568         if (!nfs_need_commit(nfsi))
 569                 return 0;
 570
 571         return nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
 572 }
 573 #else
 574 static inline int nfs_need_commit(struct nfs_inode *nfsi)
 575 {
 576         return 0;
 577 }
 578
 579 static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 580 {
 581         return 0;
 582 }
 583 #endif
 584
 585 /*
 586  * Search for an existing write request, and attempt to update
 587  * it to reflect a new dirty region on a given page.
 588  *
 589  * If the attempt fails, then the existing request is flushed out
 590  * to disk.
 591  */
 592 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
 593                 struct page *page,
 594                 unsigned int offset,
 595                 unsigned int bytes)
 596 {
 597         struct nfs_page *req;
 598         unsigned int rqend;
 599         unsigned int end;
 600         int error;
 601
 602         if (!PagePrivate(page))
 603                 return NULL;
 604
 605         end = offset + bytes;
 606         spin_lock(&inode->i_lock);
 607
 608         for (;;) {
 609                 req = nfs_page_find_request_locked(page);
 610                 if (req == NULL)
 611                         goto out_unlock;
 612
 613                 rqend = req->wb_offset + req->wb_bytes;
 614                 /*
 615                  * Tell the caller to flush out the request if
 616                  * the offsets are non-contiguous.
 617                  * Note: nfs_flush_incompatible() will already
 618                  * have flushed out requests having wrong owners.
 619                  */
 620                 if (offset > rqend
 621                     || end < req->wb_offset)
 622                         goto out_flushme;
 623
 624                 if (nfs_set_page_tag_locked(req))
 625                         break;
 626
 627                 /* The request is locked, so wait and then retry */
 628                 spin_unlock(&inode->i_lock);
 629                 error = nfs_wait_on_request(req);
 630                 nfs_release_request(req);
 631                 if (error != 0)
 632                         goto out_err;
 633                 spin_lock(&inode->i_lock);
 634         }
 635
 636         if (nfs_clear_request_commit(req))
 637                 radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
 638                                 req->wb_index, NFS_PAGE_TAG_COMMIT);
 639
 640         /* Okay, the request matches. Update the region */
 641         if (offset < req->wb_offset) {
 642                 req->wb_offset = offset;
 643                 req->wb_pgbase = offset;
 644         }
 645         if (end > rqend)
 646                 req->wb_bytes = end - req->wb_offset;
 647         else
 648                 req->wb_bytes = rqend - req->wb_offset;
 649 out_unlock:
 650         spin_unlock(&inode->i_lock);
 651         return req;
 652 out_flushme:
 653         spin_unlock(&inode->i_lock);
 654         nfs_release_request(req);
 655         error = nfs_wb_page(inode, page);
 656 out_err:
 657         return ERR_PTR(error);
 658 }
 659
 660 /*
 661  * Try to update an existing write request, or create one if there is none.
 662  *
 663  * Note: Should always be called with the Page Lock held to prevent races
 664  * if we have to add a new request. Also assumes that the caller has
 665  * already called nfs_flush_incompatible() if necessary.
 666  */
 667 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
 668                 struct page *page, unsigned int offset, unsigned int bytes)
 669 {
 670         struct inode *inode = page->mapping->host;
 671         struct nfs_page *req;
 672         int error;
 673
 674         req = nfs_try_to_update_request(inode, page, offset, bytes);
 675         if (req != NULL)
 676                 goto out;
 677         req = nfs_create_request(ctx, inode, page, offset, bytes);
 678         if (IS_ERR(req))
 679                 goto out;
 680         error = nfs_inode_add_request(inode, req);
 681         if (error != 0) {
 682                 nfs_release_request(req);
 683                 req = ERR_PTR(error);
 684         }
 685 out:
 686         return req;
 687 }
 688
 689 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 690                 unsigned int offset, unsigned int count)
 691 {
 692         struct nfs_page *req;
 693
 694         req = nfs_setup_write_request(ctx, page, offset, count);
 695         if (IS_ERR(req))
 696                 return PTR_ERR(req);
 697         /* Update file length */
 698         nfs_grow_file(page, offset, count);
 699         nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
 700         nfs_clear_page_tag_locked(req);
 701         return 0;
 702 }
 703
 704 int nfs_flush_incompatible(struct file *file, struct page *page)
 705 {
 706         struct nfs_open_context *ctx = nfs_file_open_context(file);
 707         struct nfs_page *req;
 708         int do_flush, status;
 709         /*
 710          * Look for a request corresponding to this page. If there
 711          * is one, and it belongs to another file, we flush it out
 712          * before we try to copy anything into the page. Do this
 713          * due to the lack of an ACCESS-type call in NFSv2.
 714          * Also do the same if we find a request from an existing
 715          * dropped page.
 716          */
 717         do {
 718                 req = nfs_page_find_request(page);
 719                 if (req == NULL)
 720                         return 0;
 721                 do_flush = req->wb_page != page || req->wb_context != ctx;
 722                 nfs_release_request(req);
 723                 if (!do_flush)
 724                         return 0;
 725                 status = nfs_wb_page(page->mapping->host, page);
 726         } while (status == 0);
 727         return status;
 728 }
 729
 730 /*
 731  * If the page cache is marked as unsafe or invalid, then we can't rely on
 732  * the PageUptodate() flag. In this case, we will need to turn off
 733  * write optimisations that depend on the page contents being correct.
 734  */
 735 static int nfs_write_pageuptodate(struct page *page, struct inode *inode)
 736 {
 737         return PageUptodate(page) &&
 738                 !(NFS_I(inode)->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA));
 739 }
 740
 741 /*
 742  * Update and possibly write a cached page of an NFS file.
 743  *
 744  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
 745  * things with a page scheduled for an RPC call (e.g. invalidate it).
 746  */
 747 int nfs_updatepage(struct file *file, struct page *page,
 748                 unsigned int offset, unsigned int count)
 749 {
 750         struct nfs_open_context *ctx = nfs_file_open_context(file);
 751         struct inode    *inode = page->mapping->host;
 752         int             status = 0;
 753
 754         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 755
 756         dprintk("NFS:       nfs_updatepage(%s/%s %d@%lld)\n",
 757                 file->f_path.dentry->d_parent->d_name.name,
 758                 file->f_path.dentry->d_name.name, count,
 759                 (long long)(page_offset(page) + offset));
 760
 761         /* If we're not using byte range locks, and we know the page
 762          * is up to date, it may be more efficient to extend the write
 763          * to cover the entire page in order to avoid fragmentation
 764          * inefficiencies.
 765          */
 766         if (nfs_write_pageuptodate(page, inode) &&
 767                         inode->i_flock == NULL &&
 768                         !(file->f_flags & O_SYNC)) {
 769                 count = max(count + offset, nfs_page_length(page));
 770                 offset = 0;
 771         }
 772
 773         status = nfs_writepage_setup(ctx, page, offset, count);
 774         if (status < 0)
 775                 nfs_set_pageerror(page);
 776         else
 777                 __set_page_dirty_nobuffers(page);
 778
 779         dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
 780                         status, (long long)i_size_read(inode));
 781         return status;
 782 }
 783
 784 static void nfs_writepage_release(struct nfs_page *req)
 785 {
 786
 787         if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req)) {
 788                 nfs_end_page_writeback(req->wb_page);
 789                 nfs_inode_remove_request(req);
 790         } else
 791                 nfs_end_page_writeback(req->wb_page);
 792         nfs_clear_page_tag_locked(req);
 793 }
 794
 795 static int flush_task_priority(int how)
 796 {
 797         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
 798                 case FLUSH_HIGHPRI:
 799                         return RPC_PRIORITY_HIGH;
 800                 case FLUSH_LOWPRI:
 801                         return RPC_PRIORITY_LOW;
 802         }
 803         return RPC_PRIORITY_NORMAL;
 804 }
 805
 806 /*
 807  * Set up the argument/result storage required for the RPC call.
 808  */
 809 static int nfs_write_rpcsetup(struct nfs_page *req,
 810                 struct nfs_write_data *data,
 811                 const struct rpc_call_ops *call_ops,
 812                 unsigned int count, unsigned int offset,
 813                 int how)
 814 {
 815         struct inode *inode = req->wb_context->path.dentry->d_inode;
 816         int flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
 817         int priority = flush_task_priority(how);
 818         struct rpc_task *task;
 819         struct rpc_message msg = {
 820                 .rpc_argp = &data->args,
 821                 .rpc_resp = &data->res,
 822                 .rpc_cred = req->wb_context->cred,
 823         };
 824         struct rpc_task_setup task_setup_data = {
 825                 .rpc_client = NFS_CLIENT(inode),
 826                 .task = &data->task,
 827                 .rpc_message = &msg,
 828                 .callback_ops = call_ops,
 829                 .callback_data = data,
 830                 .workqueue = nfsiod_workqueue,
 831                 .flags = flags,
 832                 .priority = priority,
 833         };
 834
 835         /* Set up the RPC argument and reply structs
 836          * NB: take care not to mess about with data->commit et al. */
 837
 838         data->req = req;
 839         data->inode = inode = req->wb_context->path.dentry->d_inode;
 840         data->cred = msg.rpc_cred;
 841
 842         data->args.fh     = NFS_FH(inode);
 843         data->args.offset = req_offset(req) + offset;
 844         data->args.pgbase = req->wb_pgbase + offset;
 845         data->args.pages  = data->pagevec;
 846         data->args.count  = count;
 847         data->args.context = get_nfs_open_context(req->wb_context);
 848         data->args.stable  = NFS_UNSTABLE;
 849         if (how & FLUSH_STABLE) {
 850                 data->args.stable = NFS_DATA_SYNC;
 851                 if (!nfs_need_commit(NFS_I(inode)))
 852                         data->args.stable = NFS_FILE_SYNC;
 853         }
 854
 855         data->res.fattr   = &data->fattr;
 856         data->res.count   = count;
 857         data->res.verf    = &data->verf;
 858         nfs_fattr_init(&data->fattr);
 859
 860         /* Set up the initial task struct.  */
 861         NFS_PROTO(inode)->write_setup(data, &msg);
 862
 863         dprintk("NFS: %5u initiated write call "
 864                 "(req %s/%lld, %u bytes @ offset %llu)\n",
 865                 data->task.tk_pid,
 866                 inode->i_sb->s_id,
 867                 (long long)NFS_FILEID(inode),
 868                 count,
 869                 (unsigned long long)data->args.offset);
 870
 871         task = rpc_run_task(&task_setup_data);
 872         if (IS_ERR(task))
 873                 return PTR_ERR(task);
 874         rpc_put_task(task);
 875         return 0;
 876 }
 877
 878 /* If a nfs_flush_* function fails, it should remove reqs from @head and
 879  * call this on each, which will prepare them to be retried on next
 880  * writeback using standard nfs.
 881  */
 882 static void nfs_redirty_request(struct nfs_page *req)
 883 {
 884         nfs_mark_request_dirty(req);
 885         nfs_end_page_writeback(req->wb_page);
 886         nfs_clear_page_tag_locked(req);
 887 }
 888
 889 /*
 890  * Generate multiple small requests to write out a single
 891  * contiguous dirty area on one page.
 892  */
 893 static int nfs_flush_multi(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int how)
 894 {
 895         struct nfs_page *req = nfs_list_entry(head->next);
 896         struct page *page = req->wb_page;
 897         struct nfs_write_data *data;
 898         size_t wsize = NFS_SERVER(inode)->wsize, nbytes;
 899         unsigned int offset;
 900         int requests = 0;
 901         int ret = 0;
 902         LIST_HEAD(list);
 903
 904         nfs_list_remove_request(req);
 905
 906         nbytes = count;
 907         do {
 908                 size_t len = min(nbytes, wsize);
 909
 910                 data = nfs_writedata_alloc(1);
 911                 if (!data)
 912                         goto out_bad;
 913                 list_add(&data->pages, &list);
 914                 requests++;
 915                 nbytes -= len;
 916         } while (nbytes != 0);
 917         atomic_set(&req->wb_complete, requests);
 918
 919         ClearPageError(page);
 920         offset = 0;
 921         nbytes = count;
 922         do {
 923                 int ret2;
 924
 925                 data = list_entry(list.next, struct nfs_write_data, pages);
 926                 list_del_init(&data->pages);
 927
 928                 data->pagevec[0] = page;
 929
 930                 if (nbytes < wsize)
 931                         wsize = nbytes;
 932                 ret2 = nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
 933                                    wsize, offset, how);
 934                 if (ret == 0)
 935                         ret = ret2;
 936                 offset += wsize;
 937                 nbytes -= wsize;
 938         } while (nbytes != 0);
 939
 940         return ret;
 941
 942 out_bad:
 943         while (!list_empty(&list)) {
 944                 data = list_entry(list.next, struct nfs_write_data, pages);
 945                 list_del(&data->pages);
 946                 nfs_writedata_release(data);
 947         }
 948         nfs_redirty_request(req);
 949         return -ENOMEM;
 950 }
 951
 952 /*
 953  * Create an RPC task for the given write request and kick it.
 954  * The page must have been locked by the caller.
 955  *
 956  * It may happen that the page we're passed is not marked dirty.
 957  * This is the case if nfs_updatepage detects a conflicting request
 958  * that has been written but not committed.
 959  */
 960 static int nfs_flush_one(struct inode *inode, struct list_head *head, unsigned int npages, size_t count, int how)
 961 {
 962         struct nfs_page         *req;
 963         struct page             **pages;
 964         struct nfs_write_data   *data;
 965
 966         data = nfs_writedata_alloc(npages);
 967         if (!data)
 968                 goto out_bad;
 969
 970         pages = data->pagevec;
 971         while (!list_empty(head)) {
 972                 req = nfs_list_entry(head->next);
 973                 nfs_list_remove_request(req);
 974                 nfs_list_add_request(req, &data->pages);
 975                 ClearPageError(req->wb_page);
 976                 *pages++ = req->wb_page;
 977         }
 978         req = nfs_list_entry(data->pages.next);
 979
 980         /* Set up the argument struct */
 981         return nfs_write_rpcsetup(req, data, &nfs_write_full_ops, count, 0, how);
 982  out_bad:
 983         while (!list_empty(head)) {
 984                 req = nfs_list_entry(head->next);
 985                 nfs_list_remove_request(req);
 986                 nfs_redirty_request(req);
 987         }
 988         return -ENOMEM;
 989 }
 990
 991 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
 992                                   struct inode *inode, int ioflags)
 993 {
 994         size_t wsize = NFS_SERVER(inode)->wsize;
 995
 996         if (wsize < PAGE_CACHE_SIZE)
 997                 nfs_pageio_init(pgio, inode, nfs_flush_multi, wsize, ioflags);
 998         else
 999                 nfs_pageio_init(pgio, inode, nfs_flush_one, wsize, ioflags);
1000 }
1001
1002 /*
1003  * Handle a write reply that flushed part of a page.
1004  */
1005 static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
1006 {
1007         struct nfs_write_data   *data = calldata;
1008
1009         dprintk("NFS: %5u write(%s/%lld %d@%lld)",
1010                 task->tk_pid,
1011                 data->req->wb_context->path.dentry->d_inode->i_sb->s_id,
1012                 (long long)
1013                   NFS_FILEID(data->req->wb_context->path.dentry->d_inode),
1014                 data->req->wb_bytes, (long long)req_offset(data->req));
1015
1016         nfs_writeback_done(task, data);
1017 }
1018
1019 static void nfs_writeback_release_partial(void *calldata)
1020 {
1021         struct nfs_write_data   *data = calldata;
1022         struct nfs_page         *req = data->req;
1023         struct page             *page = req->wb_page;
1024         int status = data->task.tk_status;
1025
1026         if (status < 0) {
1027                 nfs_set_pageerror(page);
1028                 nfs_context_set_write_error(req->wb_context, status);
1029                 dprintk(", error = %d\n", status);
1030                 goto out;
1031         }
1032
1033         if (nfs_write_need_commit(data)) {
1034                 struct inode *inode = page->mapping->host;
1035
1036                 spin_lock(&inode->i_lock);
1037                 if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
1038                         /* Do nothing we need to resend the writes */
1039                 } else if (!test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) {
1040                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1041                         dprintk(" defer commit\n");
1042                 } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
1043                         set_bit(PG_NEED_RESCHED, &req->wb_flags);
1044                         clear_bit(PG_NEED_COMMIT, &req->wb_flags);
1045                         dprintk(" server reboot detected\n");
1046                 }
1047                 spin_unlock(&inode->i_lock);
1048         } else
1049                 dprintk(" OK\n");
1050
1051 out:
1052         if (atomic_dec_and_test(&req->wb_complete))
1053                 nfs_writepage_release(req);
1054         nfs_writedata_release(calldata);
1055 }
1056
1057 #if defined(CONFIG_NFS_V4_1)
1058 void nfs_write_prepare(struct rpc_task *task, void *calldata)
1059 {
1060         struct nfs_write_data *data = calldata;
1061         struct nfs_client *clp = (NFS_SERVER(data->inode))->nfs_client;
1062
1063         if (nfs4_setup_sequence(clp, &data->args.seq_args,
1064                                 &data->res.seq_res, 1, task))
1065                 return;
1066         rpc_call_start(task);
1067 }
1068 #endif /* CONFIG_NFS_V4_1 */
1069
1070 static const struct rpc_call_ops nfs_write_partial_ops = {
1071 #if defined(CONFIG_NFS_V4_1)
1072         .rpc_call_prepare = nfs_write_prepare,
1073 #endif /* CONFIG_NFS_V4_1 */
1074         .rpc_call_done = nfs_writeback_done_partial,
1075         .rpc_release = nfs_writeback_release_partial,
1076 };
1077
1078 /*
1079  * Handle a write reply that flushes a whole page.
1080  *
1081  * FIXME: There is an inherent race with invalidate_inode_pages and
1082  *        writebacks since the page->count is kept > 1 for as long
1083  *        as the page has a write request pending.
1084  */
1085 static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
1086 {
1087         struct nfs_write_data   *data = calldata;
1088
1089         nfs_writeback_done(task, data);
1090 }
1091
1092 static void nfs_writeback_release_full(void *calldata)
1093 {
1094         struct nfs_write_data   *data = calldata;
1095         int status = data->task.tk_status;
1096
1097         /* Update attributes as result of writeback. */
1098         while (!list_empty(&data->pages)) {
1099                 struct nfs_page *req = nfs_list_entry(data->pages.next);
1100                 struct page *page = req->wb_page;
1101
1102                 nfs_list_remove_request(req);
1103
1104                 dprintk("NFS: %5u write (%s/%lld %d@%lld)",
1105                         data->task.tk_pid,
1106                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1107                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1108                         req->wb_bytes,
1109                         (long long)req_offset(req));
1110
1111                 if (status < 0) {
1112                         nfs_set_pageerror(page);
1113                         nfs_context_set_write_error(req->wb_context, status);
1114                         dprintk(", error = %d\n", status);
1115                         goto remove_request;
1116                 }
1117
1118                 if (nfs_write_need_commit(data)) {
1119                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1120                         nfs_mark_request_commit(req);
1121                         nfs_end_page_writeback(page);
1122                         dprintk(" marked for commit\n");
1123                         goto next;
1124                 }
1125                 dprintk(" OK\n");
1126 remove_request:
1127                 nfs_end_page_writeback(page);
1128                 nfs_inode_remove_request(req);
1129         next:
1130                 nfs_clear_page_tag_locked(req);
1131         }
1132         nfs_writedata_release(calldata);
1133 }
1134
1135 static const struct rpc_call_ops nfs_write_full_ops = {
1136 #if defined(CONFIG_NFS_V4_1)
1137         .rpc_call_prepare = nfs_write_prepare,
1138 #endif /* CONFIG_NFS_V4_1 */
1139         .rpc_call_done = nfs_writeback_done_full,
1140         .rpc_release = nfs_writeback_release_full,
1141 };
1142
1143
1144 /*
1145  * This function is called when the WRITE call is complete.
1146  */
1147 int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1148 {
1149         struct nfs_writeargs    *argp = &data->args;
1150         struct nfs_writeres     *resp = &data->res;
1151         struct nfs_server       *server = NFS_SERVER(data->inode);
1152         int status;
1153
1154         dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1155                 task->tk_pid, task->tk_status);
1156
1157         /*
1158          * ->write_done will attempt to use post-op attributes to detect
1159          * conflicting writes by other clients.  A strict interpretation
1160          * of close-to-open would allow us to continue caching even if
1161          * another writer had changed the file, but some applications
1162          * depend on tighter cache coherency when writing.
1163          */
1164         status = NFS_PROTO(data->inode)->write_done(task, data);
1165         if (status != 0)
1166                 return status;
1167         nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1168
1169 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1170         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1171                 /* We tried a write call, but the server did not
1172                  * commit data to stable storage even though we
1173                  * requested it.
1174                  * Note: There is a known bug in Tru64 < 5.0 in which
1175                  *       the server reports NFS_DATA_SYNC, but performs
1176                  *       NFS_FILE_SYNC. We therefore implement this checking
1177                  *       as a dprintk() in order to avoid filling syslog.
1178                  */
1179                 static unsigned long    complain;
1180
1181                 if (time_before(complain, jiffies)) {
1182                         dprintk("NFS:       faulty NFS server %s:"
1183                                 " (committed = %d) != (stable = %d)\n",
1184                                 server->nfs_client->cl_hostname,
1185                                 resp->verf->committed, argp->stable);
1186                         complain = jiffies + 300 * HZ;
1187                 }
1188         }
1189 #endif
1190         /* Is this a short write? */
1191         if (task->tk_status >= 0 && resp->count < argp->count) {
1192                 static unsigned long    complain;
1193
1194                 nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
1195
1196                 /* Has the server at least made some progress? */
1197                 if (resp->count != 0) {
1198                         /* Was this an NFSv2 write or an NFSv3 stable write? */
1199                         if (resp->verf->committed != NFS_UNSTABLE) {
1200                                 /* Resend from where the server left off */
1201                                 argp->offset += resp->count;
1202                                 argp->pgbase += resp->count;
1203                                 argp->count -= resp->count;
1204                         } else {
1205                                 /* Resend as a stable write in order to avoid
1206                                  * headaches in the case of a server crash.
1207                                  */
1208                                 argp->stable = NFS_FILE_SYNC;
1209                         }
1210                         nfs4_restart_rpc(task, server->nfs_client);
1211                         return -EAGAIN;
1212                 }
1213                 if (time_before(complain, jiffies)) {
1214                         printk(KERN_WARNING
1215                                "NFS: Server wrote zero bytes, expected %u.\n",
1216                                         argp->count);
1217                         complain = jiffies + 300 * HZ;
1218                 }
1219                 /* Can't do anything about it except throw an error. */
1220                 task->tk_status = -EIO;
1221         }
1222         nfs4_sequence_free_slot(server->nfs_client, &data->res.seq_res);
1223         return 0;
1224 }
1225
1226
1227 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1228 void nfs_commitdata_release(void *data)
1229 {
1230         struct nfs_write_data *wdata = data;
1231
1232         put_nfs_open_context(wdata->args.context);
1233         nfs_commit_free(wdata);
1234 }
1235
1236 /*
1237  * Set up the argument/result storage required for the RPC call.
1238  */
1239 static int nfs_commit_rpcsetup(struct list_head *head,
1240                 struct nfs_write_data *data,
1241                 int how)
1242 {
1243         struct nfs_page *first = nfs_list_entry(head->next);
1244         struct inode *inode = first->wb_context->path.dentry->d_inode;
1245         int flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
1246         int priority = flush_task_priority(how);
1247         struct rpc_task *task;
1248         struct rpc_message msg = {
1249                 .rpc_argp = &data->args,
1250                 .rpc_resp = &data->res,
1251                 .rpc_cred = first->wb_context->cred,
1252         };
1253         struct rpc_task_setup task_setup_data = {
1254                 .task = &data->task,
1255                 .rpc_client = NFS_CLIENT(inode),
1256                 .rpc_message = &msg,
1257                 .callback_ops = &nfs_commit_ops,
1258                 .callback_data = data,
1259                 .workqueue = nfsiod_workqueue,
1260                 .flags = flags,
1261                 .priority = priority,
1262         };
1263
1264         /* Set up the RPC argument and reply structs
1265          * NB: take care not to mess about with data->commit et al. */
1266
1267         list_splice_init(head, &data->pages);
1268
1269         data->inode       = inode;
1270         data->cred        = msg.rpc_cred;
1271
1272         data->args.fh     = NFS_FH(data->inode);
1273         /* Note: we always request a commit of the entire inode */
1274         data->args.offset = 0;
1275         data->args.count  = 0;
1276         data->args.context = get_nfs_open_context(first->wb_context);
1277         data->res.count   = 0;
1278         data->res.fattr   = &data->fattr;
1279         data->res.verf    = &data->verf;
1280         nfs_fattr_init(&data->fattr);
1281
1282         /* Set up the initial task struct.  */
1283         NFS_PROTO(inode)->commit_setup(data, &msg);
1284
1285         dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1286
1287         task = rpc_run_task(&task_setup_data);
1288         if (IS_ERR(task))
1289                 return PTR_ERR(task);
1290         rpc_put_task(task);
1291         return 0;
1292 }
1293
1294 /*
1295  * Commit dirty pages
1296  */
1297 static int
1298 nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1299 {
1300         struct nfs_write_data   *data;
1301         struct nfs_page         *req;
1302
1303         data = nfs_commitdata_alloc();
1304
1305         if (!data)
1306                 goto out_bad;
1307
1308         /* Set up the argument struct */
1309         return nfs_commit_rpcsetup(head, data, how);
1310  out_bad:
1311         while (!list_empty(head)) {
1312                 req = nfs_list_entry(head->next);
1313                 nfs_list_remove_request(req);
1314                 nfs_mark_request_commit(req);
1315                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1316                 dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
1317                                 BDI_RECLAIMABLE);
1318                 nfs_clear_page_tag_locked(req);
1319         }
1320         return -ENOMEM;
1321 }
1322
1323 /*
1324  * COMMIT call returned
1325  */
1326 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1327 {
1328         struct nfs_write_data   *data = calldata;
1329
1330         dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1331                                 task->tk_pid, task->tk_status);
1332
1333         /* Call the NFS version-specific code */
1334         if (NFS_PROTO(data->inode)->commit_done(task, data) != 0)
1335                 return;
1336 }
1337
1338 static void nfs_commit_release(void *calldata)
1339 {
1340         struct nfs_write_data   *data = calldata;
1341         struct nfs_page         *req;
1342         int status = data->task.tk_status;
1343
1344         while (!list_empty(&data->pages)) {
1345                 req = nfs_list_entry(data->pages.next);
1346                 nfs_list_remove_request(req);
1347                 nfs_clear_request_commit(req);
1348
1349                 dprintk("NFS:       commit (%s/%lld %d@%lld)",
1350                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1351                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1352                         req->wb_bytes,
1353                         (long long)req_offset(req));
1354                 if (status < 0) {
1355                         nfs_context_set_write_error(req->wb_context, status);
1356                         nfs_inode_remove_request(req);
1357                         dprintk(", error = %d\n", status);
1358                         goto next;
1359                 }
1360
1361                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1362                  * returned by the server against all stored verfs. */
1363                 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1364                         /* We have a match */
1365                         nfs_inode_remove_request(req);
1366                         dprintk(" OK\n");
1367                         goto next;
1368                 }
1369                 /* We have a mismatch. Write the page again */
1370                 dprintk(" mismatch\n");
1371                 nfs_mark_request_dirty(req);
1372         next:
1373                 nfs_clear_page_tag_locked(req);
1374         }
1375         nfs_commitdata_release(calldata);
1376 }
1377
1378 static const struct rpc_call_ops nfs_commit_ops = {
1379 #if defined(CONFIG_NFS_V4_1)
1380         .rpc_call_prepare = nfs_write_prepare,
1381 #endif /* CONFIG_NFS_V4_1 */
1382         .rpc_call_done = nfs_commit_done,
1383         .rpc_release = nfs_commit_release,
1384 };
1385
1386 int nfs_commit_inode(struct inode *inode, int how)
1387 {
1388         LIST_HEAD(head);
1389         int res;
1390
1391         spin_lock(&inode->i_lock);
1392         res = nfs_scan_commit(inode, &head, 0, 0);
1393         spin_unlock(&inode->i_lock);
1394         if (res) {
1395                 int error = nfs_commit_list(inode, &head, how);
1396                 if (error < 0)
1397                         return error;
1398         }
1399         return res;
1400 }
1401 #else
1402 static inline int nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1403 {
1404         return 0;
1405 }
1406 #endif
1407
1408 long nfs_sync_mapping_wait(struct address_space *mapping, struct writeback_control *wbc, int how)
1409 {
1410         struct inode *inode = mapping->host;
1411         pgoff_t idx_start, idx_end;
1412         unsigned int npages = 0;
1413         LIST_HEAD(head);
1414         int nocommit = how & FLUSH_NOCOMMIT;
1415         long pages, ret;
1416
1417         /* FIXME */
1418         if (wbc->range_cyclic)
1419                 idx_start = 0;
1420         else {
1421                 idx_start = wbc->range_start >> PAGE_CACHE_SHIFT;
1422                 idx_end = wbc->range_end >> PAGE_CACHE_SHIFT;
1423                 if (idx_end > idx_start) {
1424                         pgoff_t l_npages = 1 + idx_end - idx_start;
1425                         npages = l_npages;
1426                         if (sizeof(npages) != sizeof(l_npages) &&
1427                                         (pgoff_t)npages != l_npages)
1428                                 npages = 0;
1429                 }
1430         }
1431         how &= ~FLUSH_NOCOMMIT;
1432         spin_lock(&inode->i_lock);
1433         do {
1434                 ret = nfs_wait_on_requests_locked(inode, idx_start, npages);
1435                 if (ret != 0)
1436                         continue;
1437                 if (nocommit)
1438                         break;
1439                 pages = nfs_scan_commit(inode, &head, idx_start, npages);
1440                 if (pages == 0)
1441                         break;
1442                 if (how & FLUSH_INVALIDATE) {
1443                         spin_unlock(&inode->i_lock);
1444                         nfs_cancel_commit_list(&head);
1445                         ret = pages;
1446                         spin_lock(&inode->i_lock);
1447                         continue;
1448                 }
1449                 pages += nfs_scan_commit(inode, &head, 0, 0);
1450                 spin_unlock(&inode->i_lock);
1451                 ret = nfs_commit_list(inode, &head, how);
1452                 spin_lock(&inode->i_lock);
1453
1454         } while (ret >= 0);
1455         spin_unlock(&inode->i_lock);
1456         return ret;
1457 }
1458
1459 static int __nfs_write_mapping(struct address_space *mapping, struct writeback_control *wbc, int how)
1460 {
1461         int ret;
1462
1463         ret = nfs_writepages(mapping, wbc);
1464         if (ret < 0)
1465                 goto out;
1466         ret = nfs_sync_mapping_wait(mapping, wbc, how);
1467         if (ret < 0)
1468                 goto out;
1469         return 0;
1470 out:
1471         __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
1472         return ret;
1473 }
1474
1475 /* Two pass sync: first using WB_SYNC_NONE, then WB_SYNC_ALL */
1476 static int nfs_write_mapping(struct address_space *mapping, int how)
1477 {
1478         struct writeback_control wbc = {
1479                 .bdi = mapping->backing_dev_info,
1480                 .sync_mode = WB_SYNC_ALL,
1481                 .nr_to_write = LONG_MAX,
1482                 .range_start = 0,
1483                 .range_end = LLONG_MAX,
1484                 .for_writepages = 1,
1485         };
1486
1487         return __nfs_write_mapping(mapping, &wbc, how);
1488 }
1489
1490 /*
1491  * flush the inode to disk.
1492  */
1493 int nfs_wb_all(struct inode *inode)
1494 {
1495         return nfs_write_mapping(inode->i_mapping, 0);
1496 }
1497
1498 int nfs_wb_nocommit(struct inode *inode)
1499 {
1500         return nfs_write_mapping(inode->i_mapping, FLUSH_NOCOMMIT);
1501 }
1502
1503 int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1504 {
1505         struct nfs_page *req;
1506         loff_t range_start = page_offset(page);
1507         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1508         struct writeback_control wbc = {
1509                 .bdi = page->mapping->backing_dev_info,
1510                 .sync_mode = WB_SYNC_ALL,
1511                 .nr_to_write = LONG_MAX,
1512                 .range_start = range_start,
1513                 .range_end = range_end,
1514         };
1515         int ret = 0;
1516
1517         BUG_ON(!PageLocked(page));
1518         for (;;) {
1519                 req = nfs_page_find_request(page);
1520                 if (req == NULL)
1521                         goto out;
1522                 if (test_bit(PG_CLEAN, &req->wb_flags)) {
1523                         nfs_release_request(req);
1524                         break;
1525                 }
1526                 if (nfs_lock_request_dontget(req)) {
1527                         nfs_inode_remove_request(req);
1528                         /*
1529                          * In case nfs_inode_remove_request has marked the
1530                          * page as being dirty
1531                          */
1532                         cancel_dirty_page(page, PAGE_CACHE_SIZE);
1533                         nfs_unlock_request(req);
1534                         break;
1535                 }
1536                 ret = nfs_wait_on_request(req);
1537                 if (ret < 0)
1538                         goto out;
1539         }
1540         if (!PagePrivate(page))
1541                 return 0;
1542         ret = nfs_sync_mapping_wait(page->mapping, &wbc, FLUSH_INVALIDATE);
1543 out:
1544         return ret;
1545 }
1546
1547 static int nfs_wb_page_priority(struct inode *inode, struct page *page,
1548                                 int how)
1549 {
1550         loff_t range_start = page_offset(page);
1551         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1552         struct writeback_control wbc = {
1553                 .bdi = page->mapping->backing_dev_info,
1554                 .sync_mode = WB_SYNC_ALL,
1555                 .nr_to_write = LONG_MAX,
1556                 .range_start = range_start,
1557                 .range_end = range_end,
1558         };
1559         int ret;
1560
1561         do {
1562                 if (clear_page_dirty_for_io(page)) {
1563                         ret = nfs_writepage_locked(page, &wbc);
1564                         if (ret < 0)
1565                                 goto out_error;
1566                 } else if (!PagePrivate(page))
1567                         break;
1568                 ret = nfs_sync_mapping_wait(page->mapping, &wbc, how);
1569                 if (ret < 0)
1570                         goto out_error;
1571         } while (PagePrivate(page));
1572         return 0;
1573 out_error:
1574         __mark_inode_dirty(inode, I_DIRTY_PAGES);
1575         return ret;
1576 }
1577
1578 /*
1579  * Write back all requests on one page - we do this before reading it.
1580  */
1581 int nfs_wb_page(struct inode *inode, struct page* page)
1582 {
1583         return nfs_wb_page_priority(inode, page, FLUSH_STABLE);
1584 }
1585
1586 int __init nfs_init_writepagecache(void)
1587 {
1588         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1589                                              sizeof(struct nfs_write_data),
1590                                              0, SLAB_HWCACHE_ALIGN,
1591                                              NULL);
1592         if (nfs_wdata_cachep == NULL)
1593                 return -ENOMEM;
1594
1595         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1596                                                      nfs_wdata_cachep);
1597         if (nfs_wdata_mempool == NULL)
1598                 return -ENOMEM;
1599
1600         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1601                                                       nfs_wdata_cachep);
1602         if (nfs_commit_mempool == NULL)
1603                 return -ENOMEM;
1604
1605         /*
1606          * NFS congestion size, scale with available memory.
1607          *
1608          *  64MB:    8192k
1609          * 128MB:   11585k
1610          * 256MB:   16384k
1611          * 512MB:   23170k
1612          *   1GB:   32768k
1613          *   2GB:   46340k
1614          *   4GB:   65536k
1615          *   8GB:   92681k
1616          *  16GB:  131072k
1617          *
1618          * This allows larger machines to have larger/more transfers.
1619          * Limit the default to 256M
1620          */
1621         nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1622         if (nfs_congestion_kb > 256*1024)
1623                 nfs_congestion_kb = 256*1024;
1624
1625         return 0;
1626 }
1627
1628 void nfs_destroy_writepagecache(void)
1629 {
1630         mempool_destroy(nfs_commit_mempool);
1631         mempool_destroy(nfs_wdata_mempool);
1632         kmem_cache_destroy(nfs_wdata_cachep);
1633 }
1634