err.no Git - linux-2.6/blob - 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 #include <linux/smp_lock.h>
  25
  26 #include "delegation.h"
  27 #include "internal.h"
  28 #include "iostat.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 struct nfs_page * nfs_update_request(struct nfs_open_context*,
  39                                             struct page *,
  40                                             unsigned int, unsigned int);
  41 static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how);
  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_commit_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         }
  58         return p;
  59 }
  60
  61 void nfs_commit_rcu_free(struct rcu_head *head)
  62 {
  63         struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
  64         if (p && (p->pagevec != &p->page_array[0]))
  65                 kfree(p->pagevec);
  66         mempool_free(p, nfs_commit_mempool);
  67 }
  68
  69 void nfs_commit_free(struct nfs_write_data *wdata)
  70 {
  71         call_rcu_bh(&wdata->task.u.tk_rcu, nfs_commit_rcu_free);
  72 }
  73
  74 struct nfs_write_data *nfs_writedata_alloc(size_t len)
  75 {
  76         unsigned int pagecount = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
  77         struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
  78
  79         if (p) {
  80                 memset(p, 0, sizeof(*p));
  81                 INIT_LIST_HEAD(&p->pages);
  82                 p->npages = pagecount;
  83                 if (pagecount <= ARRAY_SIZE(p->page_array))
  84                         p->pagevec = p->page_array;
  85                 else {
  86                         p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
  87                         if (!p->pagevec) {
  88                                 mempool_free(p, nfs_wdata_mempool);
  89                                 p = NULL;
  90                         }
  91                 }
  92         }
  93         return p;
  94 }
  95
  96 static void nfs_writedata_rcu_free(struct rcu_head *head)
  97 {
  98         struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu);
  99         if (p && (p->pagevec != &p->page_array[0]))
 100                 kfree(p->pagevec);
 101         mempool_free(p, nfs_wdata_mempool);
 102 }
 103
 104 static void nfs_writedata_free(struct nfs_write_data *wdata)
 105 {
 106         call_rcu_bh(&wdata->task.u.tk_rcu, nfs_writedata_rcu_free);
 107 }
 108
 109 void nfs_writedata_release(void *wdata)
 110 {
 111         nfs_writedata_free(wdata);
 112 }
 113
 114 static struct nfs_page *nfs_page_find_request_locked(struct page *page)
 115 {
 116         struct nfs_page *req = NULL;
 117
 118         if (PagePrivate(page)) {
 119                 req = (struct nfs_page *)page_private(page);
 120                 if (req != NULL)
 121                         atomic_inc(&req->wb_count);
 122         }
 123         return req;
 124 }
 125
 126 static struct nfs_page *nfs_page_find_request(struct page *page)
 127 {
 128         struct nfs_page *req = NULL;
 129         spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;
 130
 131         spin_lock(req_lock);
 132         req = nfs_page_find_request_locked(page);
 133         spin_unlock(req_lock);
 134         return req;
 135 }
 136
 137 /* Adjust the file length if we're writing beyond the end */
 138 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 139 {
 140         struct inode *inode = page->mapping->host;
 141         loff_t end, i_size = i_size_read(inode);
 142         unsigned long end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 143
 144         if (i_size > 0 && page->index < end_index)
 145                 return;
 146         end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
 147         if (i_size >= end)
 148                 return;
 149         nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 150         i_size_write(inode, end);
 151 }
 152
 153 /* A writeback failed: mark the page as bad, and invalidate the page cache */
 154 static void nfs_set_pageerror(struct page *page)
 155 {
 156         SetPageError(page);
 157         nfs_zap_mapping(page->mapping->host, page->mapping);
 158 }
 159
 160 /* We can set the PG_uptodate flag if we see that a write request
 161  * covers the full page.
 162  */
 163 static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
 164 {
 165         if (PageUptodate(page))
 166                 return;
 167         if (base != 0)
 168                 return;
 169         if (count != nfs_page_length(page))
 170                 return;
 171         if (count != PAGE_CACHE_SIZE)
 172                 memclear_highpage_flush(page, count, PAGE_CACHE_SIZE - count);
 173         SetPageUptodate(page);
 174 }
 175
 176 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 177                 unsigned int offset, unsigned int count)
 178 {
 179         struct nfs_page *req;
 180         int ret;
 181
 182         for (;;) {
 183                 req = nfs_update_request(ctx, page, offset, count);
 184                 if (!IS_ERR(req))
 185                         break;
 186                 ret = PTR_ERR(req);
 187                 if (ret != -EBUSY)
 188                         return ret;
 189                 ret = nfs_wb_page(page->mapping->host, page);
 190                 if (ret != 0)
 191                         return ret;
 192         }
 193         /* Update file length */
 194         nfs_grow_file(page, offset, count);
 195         /* Set the PG_uptodate flag? */
 196         nfs_mark_uptodate(page, offset, count);
 197         nfs_unlock_request(req);
 198         return 0;
 199 }
 200
 201 static int wb_priority(struct writeback_control *wbc)
 202 {
 203         if (wbc->for_reclaim)
 204                 return FLUSH_HIGHPRI;
 205         if (wbc->for_kupdate)
 206                 return FLUSH_LOWPRI;
 207         return 0;
 208 }
 209
 210 /*
 211  * NFS congestion control
 212  */
 213
 214 int nfs_congestion_kb;
 215
 216 #define NFS_CONGESTION_ON_THRESH        (nfs_congestion_kb >> (PAGE_SHIFT-10))
 217 #define NFS_CONGESTION_OFF_THRESH       \
 218         (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 219
 220 static int nfs_set_page_writeback(struct page *page)
 221 {
 222         int ret = test_set_page_writeback(page);
 223
 224         if (!ret) {
 225                 struct inode *inode = page->mapping->host;
 226                 struct nfs_server *nfss = NFS_SERVER(inode);
 227
 228                 if (atomic_inc_return(&nfss->writeback) >
 229                                 NFS_CONGESTION_ON_THRESH)
 230                         set_bdi_congested(&nfss->backing_dev_info, WRITE);
 231         }
 232         return ret;
 233 }
 234
 235 static void nfs_end_page_writeback(struct page *page)
 236 {
 237         struct inode *inode = page->mapping->host;
 238         struct nfs_server *nfss = NFS_SERVER(inode);
 239
 240         end_page_writeback(page);
 241         if (atomic_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) {
 242                 clear_bdi_congested(&nfss->backing_dev_info, WRITE);
 243                 congestion_end(WRITE);
 244         }
 245 }
 246
 247 /*
 248  * Find an associated nfs write request, and prepare to flush it out
 249  * Returns 1 if there was no write request, or if the request was
 250  * already tagged by nfs_set_page_dirty.Returns 0 if the request
 251  * was not tagged.
 252  * May also return an error if the user signalled nfs_wait_on_request().
 253  */
 254 static int nfs_page_mark_flush(struct page *page)
 255 {
 256         struct nfs_page *req;
 257         struct nfs_inode *nfsi = NFS_I(page->mapping->host);
 258         spinlock_t *req_lock = &nfsi->req_lock;
 259         int ret;
 260
 261         spin_lock(req_lock);
 262         for(;;) {
 263                 req = nfs_page_find_request_locked(page);
 264                 if (req == NULL) {
 265                         spin_unlock(req_lock);
 266                         return 1;
 267                 }
 268                 if (nfs_lock_request_dontget(req))
 269                         break;
 270                 /* Note: If we hold the page lock, as is the case in nfs_writepage,
 271                  *       then the call to nfs_lock_request_dontget() will always
 272                  *       succeed provided that someone hasn't already marked the
 273                  *       request as dirty (in which case we don't care).
 274                  */
 275                 spin_unlock(req_lock);
 276                 ret = nfs_wait_on_request(req);
 277                 nfs_release_request(req);
 278                 if (ret != 0)
 279                         return ret;
 280                 spin_lock(req_lock);
 281         }
 282         if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
 283                 /* This request is marked for commit */
 284                 spin_unlock(req_lock);
 285                 nfs_unlock_request(req);
 286                 return 1;
 287         }
 288         if (nfs_set_page_writeback(page) == 0) {
 289                 nfs_list_remove_request(req);
 290                 /* add the request to the inode's dirty list. */
 291                 radix_tree_tag_set(&nfsi->nfs_page_tree,
 292                                 req->wb_index, NFS_PAGE_TAG_DIRTY);
 293                 nfs_list_add_request(req, &nfsi->dirty);
 294                 nfsi->ndirty++;
 295                 spin_unlock(req_lock);
 296                 __mark_inode_dirty(page->mapping->host, I_DIRTY_PAGES);
 297         } else
 298                 spin_unlock(req_lock);
 299         ret = test_bit(PG_NEED_FLUSH, &req->wb_flags);
 300         nfs_unlock_request(req);
 301         return ret;
 302 }
 303
 304 /*
 305  * Write an mmapped page to the server.
 306  */
 307 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 308 {
 309         struct nfs_open_context *ctx;
 310         struct inode *inode = page->mapping->host;
 311         unsigned offset;
 312         int err;
 313
 314         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 315         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 316
 317         err = nfs_page_mark_flush(page);
 318         if (err <= 0)
 319                 goto out;
 320         err = 0;
 321         offset = nfs_page_length(page);
 322         if (!offset)
 323                 goto out;
 324
 325         ctx = nfs_find_open_context(inode, NULL, FMODE_WRITE);
 326         if (ctx == NULL) {
 327                 err = -EBADF;
 328                 goto out;
 329         }
 330         err = nfs_writepage_setup(ctx, page, 0, offset);
 331         put_nfs_open_context(ctx);
 332         if (err != 0)
 333                 goto out;
 334         err = nfs_page_mark_flush(page);
 335         if (err > 0)
 336                 err = 0;
 337 out:
 338         if (!wbc->for_writepages)
 339                 nfs_flush_mapping(page->mapping, wbc, FLUSH_STABLE|wb_priority(wbc));
 340         return err;
 341 }
 342
 343 int nfs_writepage(struct page *page, struct writeback_control *wbc)
 344 {
 345         int err;
 346
 347         err = nfs_writepage_locked(page, wbc);
 348         unlock_page(page);
 349         return err;
 350 }
 351
 352 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 353 {
 354         struct inode *inode = mapping->host;
 355         int err;
 356
 357         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 358
 359         err = generic_writepages(mapping, wbc);
 360         if (err)
 361                 return err;
 362         err = nfs_flush_mapping(mapping, wbc, wb_priority(wbc));
 363         if (err < 0)
 364                 goto out;
 365         nfs_add_stats(inode, NFSIOS_WRITEPAGES, err);
 366         err = 0;
 367 out:
 368         return err;
 369 }
 370
 371 /*
 372  * Insert a write request into an inode
 373  */
 374 static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 375 {
 376         struct nfs_inode *nfsi = NFS_I(inode);
 377         int error;
 378
 379         error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
 380         BUG_ON(error == -EEXIST);
 381         if (error)
 382                 return error;
 383         if (!nfsi->npages) {
 384                 igrab(inode);
 385                 nfs_begin_data_update(inode);
 386                 if (nfs_have_delegation(inode, FMODE_WRITE))
 387                         nfsi->change_attr++;
 388         }
 389         SetPagePrivate(req->wb_page);
 390         set_page_private(req->wb_page, (unsigned long)req);
 391         nfsi->npages++;
 392         atomic_inc(&req->wb_count);
 393         return 0;
 394 }
 395
 396 /*
 397  * Remove a write request from an inode
 398  */
 399 static void nfs_inode_remove_request(struct nfs_page *req)
 400 {
 401         struct inode *inode = req->wb_context->dentry->d_inode;
 402         struct nfs_inode *nfsi = NFS_I(inode);
 403
 404         BUG_ON (!NFS_WBACK_BUSY(req));
 405
 406         spin_lock(&nfsi->req_lock);
 407         set_page_private(req->wb_page, 0);
 408         ClearPagePrivate(req->wb_page);
 409         radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
 410         nfsi->npages--;
 411         if (!nfsi->npages) {
 412                 spin_unlock(&nfsi->req_lock);
 413                 nfs_end_data_update(inode);
 414                 iput(inode);
 415         } else
 416                 spin_unlock(&nfsi->req_lock);
 417         nfs_clear_request(req);
 418         nfs_release_request(req);
 419 }
 420
 421 static void
 422 nfs_redirty_request(struct nfs_page *req)
 423 {
 424         __set_page_dirty_nobuffers(req->wb_page);
 425 }
 426
 427 /*
 428  * Check if a request is dirty
 429  */
 430 static inline int
 431 nfs_dirty_request(struct nfs_page *req)
 432 {
 433         struct page *page = req->wb_page;
 434
 435         if (page == NULL || test_bit(PG_NEED_COMMIT, &req->wb_flags))
 436                 return 0;
 437         return !PageWriteback(req->wb_page);
 438 }
 439
 440 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 441 /*
 442  * Add a request to the inode's commit list.
 443  */
 444 static void
 445 nfs_mark_request_commit(struct nfs_page *req)
 446 {
 447         struct inode *inode = req->wb_context->dentry->d_inode;
 448         struct nfs_inode *nfsi = NFS_I(inode);
 449
 450         spin_lock(&nfsi->req_lock);
 451         nfs_list_add_request(req, &nfsi->commit);
 452         nfsi->ncommit++;
 453         set_bit(PG_NEED_COMMIT, &(req)->wb_flags);
 454         spin_unlock(&nfsi->req_lock);
 455         inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 456         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 457 }
 458
 459 static inline
 460 int nfs_write_need_commit(struct nfs_write_data *data)
 461 {
 462         return data->verf.committed != NFS_FILE_SYNC;
 463 }
 464
 465 static inline
 466 int nfs_reschedule_unstable_write(struct nfs_page *req)
 467 {
 468         if (test_bit(PG_NEED_COMMIT, &req->wb_flags)) {
 469                 nfs_mark_request_commit(req);
 470                 return 1;
 471         }
 472         if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
 473                 nfs_redirty_request(req);
 474                 return 1;
 475         }
 476         return 0;
 477 }
 478 #else
 479 static inline void
 480 nfs_mark_request_commit(struct nfs_page *req)
 481 {
 482 }
 483
 484 static inline
 485 int nfs_write_need_commit(struct nfs_write_data *data)
 486 {
 487         return 0;
 488 }
 489
 490 static inline
 491 int nfs_reschedule_unstable_write(struct nfs_page *req)
 492 {
 493         return 0;
 494 }
 495 #endif
 496
 497 /*
 498  * Wait for a request to complete.
 499  *
 500  * Interruptible by signals only if mounted with intr flag.
 501  */
 502 static int nfs_wait_on_requests_locked(struct inode *inode, unsigned long idx_start, unsigned int npages)
 503 {
 504         struct nfs_inode *nfsi = NFS_I(inode);
 505         struct nfs_page *req;
 506         unsigned long           idx_end, next;
 507         unsigned int            res = 0;
 508         int                     error;
 509
 510         if (npages == 0)
 511                 idx_end = ~0;
 512         else
 513                 idx_end = idx_start + npages - 1;
 514
 515         next = idx_start;
 516         while (radix_tree_gang_lookup_tag(&nfsi->nfs_page_tree, (void **)&req, next, 1, NFS_PAGE_TAG_WRITEBACK)) {
 517                 if (req->wb_index > idx_end)
 518                         break;
 519
 520                 next = req->wb_index + 1;
 521                 BUG_ON(!NFS_WBACK_BUSY(req));
 522
 523                 atomic_inc(&req->wb_count);
 524                 spin_unlock(&nfsi->req_lock);
 525                 error = nfs_wait_on_request(req);
 526                 nfs_release_request(req);
 527                 spin_lock(&nfsi->req_lock);
 528                 if (error < 0)
 529                         return error;
 530                 res++;
 531         }
 532         return res;
 533 }
 534
 535 static void nfs_cancel_dirty_list(struct list_head *head)
 536 {
 537         struct nfs_page *req;
 538         while(!list_empty(head)) {
 539                 req = nfs_list_entry(head->next);
 540                 nfs_list_remove_request(req);
 541                 nfs_end_page_writeback(req->wb_page);
 542                 nfs_inode_remove_request(req);
 543                 nfs_clear_page_writeback(req);
 544         }
 545 }
 546
 547 static void nfs_cancel_commit_list(struct list_head *head)
 548 {
 549         struct nfs_page *req;
 550
 551         while(!list_empty(head)) {
 552                 req = nfs_list_entry(head->next);
 553                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 554                 nfs_list_remove_request(req);
 555                 clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
 556                 nfs_inode_remove_request(req);
 557                 nfs_unlock_request(req);
 558         }
 559 }
 560
 561 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 562 /*
 563  * nfs_scan_commit - Scan an inode for commit requests
 564  * @inode: NFS inode to scan
 565  * @dst: destination list
 566  * @idx_start: lower bound of page->index to scan.
 567  * @npages: idx_start + npages sets the upper bound to scan.
 568  *
 569  * Moves requests from the inode's 'commit' request list.
 570  * The requests are *not* checked to ensure that they form a contiguous set.
 571  */
 572 static int
 573 nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
 574 {
 575         struct nfs_inode *nfsi = NFS_I(inode);
 576         int res = 0;
 577
 578         if (nfsi->ncommit != 0) {
 579                 res = nfs_scan_list(nfsi, &nfsi->commit, dst, idx_start, npages);
 580                 nfsi->ncommit -= res;
 581                 if ((nfsi->ncommit == 0) != list_empty(&nfsi->commit))
 582                         printk(KERN_ERR "NFS: desynchronized value of nfs_i.ncommit.\n");
 583         }
 584         return res;
 585 }
 586 #else
 587 static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, unsigned long idx_start, unsigned int npages)
 588 {
 589         return 0;
 590 }
 591 #endif
 592
 593 static int nfs_wait_on_write_congestion(struct address_space *mapping)
 594 {
 595         struct inode *inode = mapping->host;
 596         struct backing_dev_info *bdi = mapping->backing_dev_info;
 597         int ret = 0;
 598
 599         might_sleep();
 600
 601         if (!bdi_write_congested(bdi))
 602                 return 0;
 603
 604         nfs_inc_stats(inode, NFSIOS_CONGESTIONWAIT);
 605
 606         do {
 607                 struct rpc_clnt *clnt = NFS_CLIENT(inode);
 608                 sigset_t oldset;
 609
 610                 rpc_clnt_sigmask(clnt, &oldset);
 611                 ret = congestion_wait_interruptible(WRITE, HZ/10);
 612                 rpc_clnt_sigunmask(clnt, &oldset);
 613                 if (ret == -ERESTARTSYS)
 614                         break;
 615                 ret = 0;
 616         } while (bdi_write_congested(bdi));
 617
 618         return ret;
 619 }
 620
 621 /*
 622  * Try to update any existing write request, or create one if there is none.
 623  * In order to match, the request's credentials must match those of
 624  * the calling process.
 625  *
 626  * Note: Should always be called with the Page Lock held!
 627  */
 628 static struct nfs_page * nfs_update_request(struct nfs_open_context* ctx,
 629                 struct page *page, unsigned int offset, unsigned int bytes)
 630 {
 631         struct address_space *mapping = page->mapping;
 632         struct inode *inode = mapping->host;
 633         struct nfs_inode *nfsi = NFS_I(inode);
 634         struct nfs_page         *req, *new = NULL;
 635         unsigned long           rqend, end;
 636
 637         end = offset + bytes;
 638
 639         if (nfs_wait_on_write_congestion(mapping))
 640                 return ERR_PTR(-ERESTARTSYS);
 641         for (;;) {
 642                 /* Loop over all inode entries and see if we find
 643                  * A request for the page we wish to update
 644                  */
 645                 spin_lock(&nfsi->req_lock);
 646                 req = nfs_page_find_request_locked(page);
 647                 if (req) {
 648                         if (!nfs_lock_request_dontget(req)) {
 649                                 int error;
 650
 651                                 spin_unlock(&nfsi->req_lock);
 652                                 error = nfs_wait_on_request(req);
 653                                 nfs_release_request(req);
 654                                 if (error < 0) {
 655                                         if (new)
 656                                                 nfs_release_request(new);
 657                                         return ERR_PTR(error);
 658                                 }
 659                                 continue;
 660                         }
 661                         spin_unlock(&nfsi->req_lock);
 662                         if (new)
 663                                 nfs_release_request(new);
 664                         break;
 665                 }
 666
 667                 if (new) {
 668                         int error;
 669                         nfs_lock_request_dontget(new);
 670                         error = nfs_inode_add_request(inode, new);
 671                         if (error) {
 672                                 spin_unlock(&nfsi->req_lock);
 673                                 nfs_unlock_request(new);
 674                                 return ERR_PTR(error);
 675                         }
 676                         spin_unlock(&nfsi->req_lock);
 677                         return new;
 678                 }
 679                 spin_unlock(&nfsi->req_lock);
 680
 681                 new = nfs_create_request(ctx, inode, page, offset, bytes);
 682                 if (IS_ERR(new))
 683                         return new;
 684         }
 685
 686         /* We have a request for our page.
 687          * If the creds don't match, or the
 688          * page addresses don't match,
 689          * tell the caller to wait on the conflicting
 690          * request.
 691          */
 692         rqend = req->wb_offset + req->wb_bytes;
 693         if (req->wb_context != ctx
 694             || req->wb_page != page
 695             || !nfs_dirty_request(req)
 696             || offset > rqend || end < req->wb_offset) {
 697                 nfs_unlock_request(req);
 698                 return ERR_PTR(-EBUSY);
 699         }
 700
 701         /* Okay, the request matches. Update the region */
 702         if (offset < req->wb_offset) {
 703                 req->wb_offset = offset;
 704                 req->wb_pgbase = offset;
 705                 req->wb_bytes = rqend - req->wb_offset;
 706         }
 707
 708         if (end > rqend)
 709                 req->wb_bytes = end - req->wb_offset;
 710
 711         return req;
 712 }
 713
 714 int nfs_flush_incompatible(struct file *file, struct page *page)
 715 {
 716         struct nfs_open_context *ctx = (struct nfs_open_context *)file->private_data;
 717         struct nfs_page *req;
 718         int do_flush, status;
 719         /*
 720          * Look for a request corresponding to this page. If there
 721          * is one, and it belongs to another file, we flush it out
 722          * before we try to copy anything into the page. Do this
 723          * due to the lack of an ACCESS-type call in NFSv2.
 724          * Also do the same if we find a request from an existing
 725          * dropped page.
 726          */
 727         do {
 728                 req = nfs_page_find_request(page);
 729                 if (req == NULL)
 730                         return 0;
 731                 do_flush = req->wb_page != page || req->wb_context != ctx
 732                         || !nfs_dirty_request(req);
 733                 nfs_release_request(req);
 734                 if (!do_flush)
 735                         return 0;
 736                 status = nfs_wb_page(page->mapping->host, page);
 737         } while (status == 0);
 738         return status;
 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 = (struct nfs_open_context *)file->private_data;
 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@%Ld)\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 entirely in cache, it may be more efficient to avoid
 763          * fragmenting write requests.
 764          */
 765         if (PageUptodate(page) && inode->i_flock == NULL && !(file->f_mode & 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         __set_page_dirty_nobuffers(page);
 772
 773         dprintk("NFS:      nfs_updatepage returns %d (isize %Ld)\n",
 774                         status, (long long)i_size_read(inode));
 775         if (status < 0)
 776                 nfs_set_pageerror(page);
 777         return status;
 778 }
 779
 780 static void nfs_writepage_release(struct nfs_page *req)
 781 {
 782
 783         if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req)) {
 784                 nfs_end_page_writeback(req->wb_page);
 785                 nfs_inode_remove_request(req);
 786         } else
 787                 nfs_end_page_writeback(req->wb_page);
 788         nfs_clear_page_writeback(req);
 789 }
 790
 791 static inline int flush_task_priority(int how)
 792 {
 793         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
 794                 case FLUSH_HIGHPRI:
 795                         return RPC_PRIORITY_HIGH;
 796                 case FLUSH_LOWPRI:
 797                         return RPC_PRIORITY_LOW;
 798         }
 799         return RPC_PRIORITY_NORMAL;
 800 }
 801
 802 /*
 803  * Set up the argument/result storage required for the RPC call.
 804  */
 805 static void nfs_write_rpcsetup(struct nfs_page *req,
 806                 struct nfs_write_data *data,
 807                 const struct rpc_call_ops *call_ops,
 808                 unsigned int count, unsigned int offset,
 809                 int how)
 810 {
 811         struct inode            *inode;
 812         int flags;
 813
 814         /* Set up the RPC argument and reply structs
 815          * NB: take care not to mess about with data->commit et al. */
 816
 817         data->req = req;
 818         data->inode = inode = req->wb_context->dentry->d_inode;
 819         data->cred = req->wb_context->cred;
 820
 821         data->args.fh     = NFS_FH(inode);
 822         data->args.offset = req_offset(req) + offset;
 823         data->args.pgbase = req->wb_pgbase + offset;
 824         data->args.pages  = data->pagevec;
 825         data->args.count  = count;
 826         data->args.context = req->wb_context;
 827
 828         data->res.fattr   = &data->fattr;
 829         data->res.count   = count;
 830         data->res.verf    = &data->verf;
 831         nfs_fattr_init(&data->fattr);
 832
 833         /* Set up the initial task struct.  */
 834         flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
 835         rpc_init_task(&data->task, NFS_CLIENT(inode), flags, call_ops, data);
 836         NFS_PROTO(inode)->write_setup(data, how);
 837
 838         data->task.tk_priority = flush_task_priority(how);
 839         data->task.tk_cookie = (unsigned long)inode;
 840
 841         dprintk("NFS: %5u initiated write call "
 842                 "(req %s/%Ld, %u bytes @ offset %Lu)\n",
 843                 data->task.tk_pid,
 844                 inode->i_sb->s_id,
 845                 (long long)NFS_FILEID(inode),
 846                 count,
 847                 (unsigned long long)data->args.offset);
 848 }
 849
 850 static void nfs_execute_write(struct nfs_write_data *data)
 851 {
 852         struct rpc_clnt *clnt = NFS_CLIENT(data->inode);
 853         sigset_t oldset;
 854
 855         rpc_clnt_sigmask(clnt, &oldset);
 856         rpc_execute(&data->task);
 857         rpc_clnt_sigunmask(clnt, &oldset);
 858 }
 859
 860 /*
 861  * Generate multiple small requests to write out a single
 862  * contiguous dirty area on one page.
 863  */
 864 static int nfs_flush_multi(struct inode *inode, struct list_head *head, int how)
 865 {
 866         struct nfs_page *req = nfs_list_entry(head->next);
 867         struct page *page = req->wb_page;
 868         struct nfs_write_data *data;
 869         size_t wsize = NFS_SERVER(inode)->wsize, nbytes;
 870         unsigned int offset;
 871         int requests = 0;
 872         LIST_HEAD(list);
 873
 874         nfs_list_remove_request(req);
 875
 876         nbytes = req->wb_bytes;
 877         do {
 878                 size_t len = min(nbytes, wsize);
 879
 880                 data = nfs_writedata_alloc(len);
 881                 if (!data)
 882                         goto out_bad;
 883                 list_add(&data->pages, &list);
 884                 requests++;
 885                 nbytes -= len;
 886         } while (nbytes != 0);
 887         atomic_set(&req->wb_complete, requests);
 888
 889         ClearPageError(page);
 890         offset = 0;
 891         nbytes = req->wb_bytes;
 892         do {
 893                 data = list_entry(list.next, struct nfs_write_data, pages);
 894                 list_del_init(&data->pages);
 895
 896                 data->pagevec[0] = page;
 897
 898                 if (nbytes > wsize) {
 899                         nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
 900                                         wsize, offset, how);
 901                         offset += wsize;
 902                         nbytes -= wsize;
 903                 } else {
 904                         nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
 905                                         nbytes, offset, how);
 906                         nbytes = 0;
 907                 }
 908                 nfs_execute_write(data);
 909         } while (nbytes != 0);
 910
 911         return 0;
 912
 913 out_bad:
 914         while (!list_empty(&list)) {
 915                 data = list_entry(list.next, struct nfs_write_data, pages);
 916                 list_del(&data->pages);
 917                 nfs_writedata_release(data);
 918         }
 919         nfs_redirty_request(req);
 920         nfs_end_page_writeback(req->wb_page);
 921         nfs_clear_page_writeback(req);
 922         return -ENOMEM;
 923 }
 924
 925 /*
 926  * Create an RPC task for the given write request and kick it.
 927  * The page must have been locked by the caller.
 928  *
 929  * It may happen that the page we're passed is not marked dirty.
 930  * This is the case if nfs_updatepage detects a conflicting request
 931  * that has been written but not committed.
 932  */
 933 static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
 934 {
 935         struct nfs_page         *req;
 936         struct page             **pages;
 937         struct nfs_write_data   *data;
 938         unsigned int            count;
 939
 940         data = nfs_writedata_alloc(NFS_SERVER(inode)->wsize);
 941         if (!data)
 942                 goto out_bad;
 943
 944         pages = data->pagevec;
 945         count = 0;
 946         while (!list_empty(head)) {
 947                 req = nfs_list_entry(head->next);
 948                 nfs_list_remove_request(req);
 949                 nfs_list_add_request(req, &data->pages);
 950                 ClearPageError(req->wb_page);
 951                 *pages++ = req->wb_page;
 952                 count += req->wb_bytes;
 953         }
 954         req = nfs_list_entry(data->pages.next);
 955
 956         /* Set up the argument struct */
 957         nfs_write_rpcsetup(req, data, &nfs_write_full_ops, count, 0, how);
 958
 959         nfs_execute_write(data);
 960         return 0;
 961  out_bad:
 962         while (!list_empty(head)) {
 963                 struct nfs_page *req = nfs_list_entry(head->next);
 964                 nfs_list_remove_request(req);
 965                 nfs_redirty_request(req);
 966                 nfs_end_page_writeback(req->wb_page);
 967                 nfs_clear_page_writeback(req);
 968         }
 969         return -ENOMEM;
 970 }
 971
 972 static int nfs_flush_list(struct inode *inode, struct list_head *head, int npages, int how)
 973 {
 974         LIST_HEAD(one_request);
 975         int (*flush_one)(struct inode *, struct list_head *, int);
 976         struct nfs_page *req;
 977         int wpages = NFS_SERVER(inode)->wpages;
 978         int wsize = NFS_SERVER(inode)->wsize;
 979         int error;
 980
 981         flush_one = nfs_flush_one;
 982         if (wsize < PAGE_CACHE_SIZE)
 983                 flush_one = nfs_flush_multi;
 984         /* For single writes, FLUSH_STABLE is more efficient */
 985         if (npages <= wpages && npages == NFS_I(inode)->npages
 986                         && nfs_list_entry(head->next)->wb_bytes <= wsize)
 987                 how |= FLUSH_STABLE;
 988
 989         do {
 990                 nfs_coalesce_requests(head, &one_request, wpages);
 991                 req = nfs_list_entry(one_request.next);
 992                 error = flush_one(inode, &one_request, how);
 993                 if (error < 0)
 994                         goto out_err;
 995         } while (!list_empty(head));
 996         return 0;
 997 out_err:
 998         while (!list_empty(head)) {
 999                 req = nfs_list_entry(head->next);
1000                 nfs_list_remove_request(req);
1001                 nfs_redirty_request(req);
1002                 nfs_end_page_writeback(req->wb_page);
1003                 nfs_clear_page_writeback(req);
1004         }
1005         return error;
1006 }
1007
1008 /*
1009  * Handle a write reply that flushed part of a page.
1010  */
1011 static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
1012 {
1013         struct nfs_write_data   *data = calldata;
1014         struct nfs_page         *req = data->req;
1015         struct page             *page = req->wb_page;
1016
1017         dprintk("NFS: write (%s/%Ld %d@%Ld)",
1018                 req->wb_context->dentry->d_inode->i_sb->s_id,
1019                 (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1020                 req->wb_bytes,
1021                 (long long)req_offset(req));
1022
1023         if (nfs_writeback_done(task, data) != 0)
1024                 return;
1025
1026         if (task->tk_status < 0) {
1027                 nfs_set_pageerror(page);
1028                 req->wb_context->error = task->tk_status;
1029                 dprintk(", error = %d\n", task->tk_status);
1030                 goto out;
1031         }
1032
1033         if (nfs_write_need_commit(data)) {
1034                 spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;
1035
1036                 spin_lock(req_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(req_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 }
1055
1056 static const struct rpc_call_ops nfs_write_partial_ops = {
1057         .rpc_call_done = nfs_writeback_done_partial,
1058         .rpc_release = nfs_writedata_release,
1059 };
1060
1061 /*
1062  * Handle a write reply that flushes a whole page.
1063  *
1064  * FIXME: There is an inherent race with invalidate_inode_pages and
1065  *        writebacks since the page->count is kept > 1 for as long
1066  *        as the page has a write request pending.
1067  */
1068 static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
1069 {
1070         struct nfs_write_data   *data = calldata;
1071         struct nfs_page         *req;
1072         struct page             *page;
1073
1074         if (nfs_writeback_done(task, data) != 0)
1075                 return;
1076
1077         /* Update attributes as result of writeback. */
1078         while (!list_empty(&data->pages)) {
1079                 req = nfs_list_entry(data->pages.next);
1080                 nfs_list_remove_request(req);
1081                 page = req->wb_page;
1082
1083                 dprintk("NFS: write (%s/%Ld %d@%Ld)",
1084                         req->wb_context->dentry->d_inode->i_sb->s_id,
1085                         (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1086                         req->wb_bytes,
1087                         (long long)req_offset(req));
1088
1089                 if (task->tk_status < 0) {
1090                         nfs_set_pageerror(page);
1091                         req->wb_context->error = task->tk_status;
1092                         dprintk(", error = %d\n", task->tk_status);
1093                         goto remove_request;
1094                 }
1095
1096                 if (nfs_write_need_commit(data)) {
1097                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1098                         nfs_mark_request_commit(req);
1099                         nfs_end_page_writeback(page);
1100                         dprintk(" marked for commit\n");
1101                         goto next;
1102                 }
1103                 dprintk(" OK\n");
1104 remove_request:
1105                 nfs_end_page_writeback(page);
1106                 nfs_inode_remove_request(req);
1107         next:
1108                 nfs_clear_page_writeback(req);
1109         }
1110 }
1111
1112 static const struct rpc_call_ops nfs_write_full_ops = {
1113         .rpc_call_done = nfs_writeback_done_full,
1114         .rpc_release = nfs_writedata_release,
1115 };
1116
1117
1118 /*
1119  * This function is called when the WRITE call is complete.
1120  */
1121 int nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1122 {
1123         struct nfs_writeargs    *argp = &data->args;
1124         struct nfs_writeres     *resp = &data->res;
1125         int status;
1126
1127         dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1128                 task->tk_pid, task->tk_status);
1129
1130         /*
1131          * ->write_done will attempt to use post-op attributes to detect
1132          * conflicting writes by other clients.  A strict interpretation
1133          * of close-to-open would allow us to continue caching even if
1134          * another writer had changed the file, but some applications
1135          * depend on tighter cache coherency when writing.
1136          */
1137         status = NFS_PROTO(data->inode)->write_done(task, data);
1138         if (status != 0)
1139                 return status;
1140         nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1141
1142 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1143         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1144                 /* We tried a write call, but the server did not
1145                  * commit data to stable storage even though we
1146                  * requested it.
1147                  * Note: There is a known bug in Tru64 < 5.0 in which
1148                  *       the server reports NFS_DATA_SYNC, but performs
1149                  *       NFS_FILE_SYNC. We therefore implement this checking
1150                  *       as a dprintk() in order to avoid filling syslog.
1151                  */
1152                 static unsigned long    complain;
1153
1154                 if (time_before(complain, jiffies)) {
1155                         dprintk("NFS: faulty NFS server %s:"
1156                                 " (committed = %d) != (stable = %d)\n",
1157                                 NFS_SERVER(data->inode)->nfs_client->cl_hostname,
1158                                 resp->verf->committed, argp->stable);
1159                         complain = jiffies + 300 * HZ;
1160                 }
1161         }
1162 #endif
1163         /* Is this a short write? */
1164         if (task->tk_status >= 0 && resp->count < argp->count) {
1165                 static unsigned long    complain;
1166
1167                 nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
1168
1169                 /* Has the server at least made some progress? */
1170                 if (resp->count != 0) {
1171                         /* Was this an NFSv2 write or an NFSv3 stable write? */
1172                         if (resp->verf->committed != NFS_UNSTABLE) {
1173                                 /* Resend from where the server left off */
1174                                 argp->offset += resp->count;
1175                                 argp->pgbase += resp->count;
1176                                 argp->count -= resp->count;
1177                         } else {
1178                                 /* Resend as a stable write in order to avoid
1179                                  * headaches in the case of a server crash.
1180                                  */
1181                                 argp->stable = NFS_FILE_SYNC;
1182                         }
1183                         rpc_restart_call(task);
1184                         return -EAGAIN;
1185                 }
1186                 if (time_before(complain, jiffies)) {
1187                         printk(KERN_WARNING
1188                                "NFS: Server wrote zero bytes, expected %u.\n",
1189                                         argp->count);
1190                         complain = jiffies + 300 * HZ;
1191                 }
1192                 /* Can't do anything about it except throw an error. */
1193                 task->tk_status = -EIO;
1194         }
1195         return 0;
1196 }
1197
1198
1199 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1200 void nfs_commit_release(void *wdata)
1201 {
1202         nfs_commit_free(wdata);
1203 }
1204
1205 /*
1206  * Set up the argument/result storage required for the RPC call.
1207  */
1208 static void nfs_commit_rpcsetup(struct list_head *head,
1209                 struct nfs_write_data *data,
1210                 int how)
1211 {
1212         struct nfs_page         *first;
1213         struct inode            *inode;
1214         int flags;
1215
1216         /* Set up the RPC argument and reply structs
1217          * NB: take care not to mess about with data->commit et al. */
1218
1219         list_splice_init(head, &data->pages);
1220         first = nfs_list_entry(data->pages.next);
1221         inode = first->wb_context->dentry->d_inode;
1222
1223         data->inode       = inode;
1224         data->cred        = first->wb_context->cred;
1225
1226         data->args.fh     = NFS_FH(data->inode);
1227         /* Note: we always request a commit of the entire inode */
1228         data->args.offset = 0;
1229         data->args.count  = 0;
1230         data->res.count   = 0;
1231         data->res.fattr   = &data->fattr;
1232         data->res.verf    = &data->verf;
1233         nfs_fattr_init(&data->fattr);
1234
1235         /* Set up the initial task struct.  */
1236         flags = (how & FLUSH_SYNC) ? 0 : RPC_TASK_ASYNC;
1237         rpc_init_task(&data->task, NFS_CLIENT(inode), flags, &nfs_commit_ops, data);
1238         NFS_PROTO(inode)->commit_setup(data, how);
1239
1240         data->task.tk_priority = flush_task_priority(how);
1241         data->task.tk_cookie = (unsigned long)inode;
1242
1243         dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1244 }
1245
1246 /*
1247  * Commit dirty pages
1248  */
1249 static int
1250 nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1251 {
1252         struct nfs_write_data   *data;
1253         struct nfs_page         *req;
1254
1255         data = nfs_commit_alloc();
1256
1257         if (!data)
1258                 goto out_bad;
1259
1260         /* Set up the argument struct */
1261         nfs_commit_rpcsetup(head, data, how);
1262
1263         nfs_execute_write(data);
1264         return 0;
1265  out_bad:
1266         while (!list_empty(head)) {
1267                 req = nfs_list_entry(head->next);
1268                 nfs_list_remove_request(req);
1269                 nfs_mark_request_commit(req);
1270                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1271                 nfs_clear_page_writeback(req);
1272         }
1273         return -ENOMEM;
1274 }
1275
1276 /*
1277  * COMMIT call returned
1278  */
1279 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1280 {
1281         struct nfs_write_data   *data = calldata;
1282         struct nfs_page         *req;
1283
1284         dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1285                                 task->tk_pid, task->tk_status);
1286
1287         /* Call the NFS version-specific code */
1288         if (NFS_PROTO(data->inode)->commit_done(task, data) != 0)
1289                 return;
1290
1291         while (!list_empty(&data->pages)) {
1292                 req = nfs_list_entry(data->pages.next);
1293                 nfs_list_remove_request(req);
1294                 clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
1295                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1296
1297                 dprintk("NFS: commit (%s/%Ld %d@%Ld)",
1298                         req->wb_context->dentry->d_inode->i_sb->s_id,
1299                         (long long)NFS_FILEID(req->wb_context->dentry->d_inode),
1300                         req->wb_bytes,
1301                         (long long)req_offset(req));
1302                 if (task->tk_status < 0) {
1303                         req->wb_context->error = task->tk_status;
1304                         nfs_inode_remove_request(req);
1305                         dprintk(", error = %d\n", task->tk_status);
1306                         goto next;
1307                 }
1308
1309                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1310                  * returned by the server against all stored verfs. */
1311                 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1312                         /* We have a match */
1313                         nfs_inode_remove_request(req);
1314                         dprintk(" OK\n");
1315                         goto next;
1316                 }
1317                 /* We have a mismatch. Write the page again */
1318                 dprintk(" mismatch\n");
1319                 nfs_redirty_request(req);
1320         next:
1321                 nfs_clear_page_writeback(req);
1322         }
1323 }
1324
1325 static const struct rpc_call_ops nfs_commit_ops = {
1326         .rpc_call_done = nfs_commit_done,
1327         .rpc_release = nfs_commit_release,
1328 };
1329 #else
1330 static inline int nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1331 {
1332         return 0;
1333 }
1334 #endif
1335
1336 static long nfs_flush_mapping(struct address_space *mapping, struct writeback_control *wbc, int how)
1337 {
1338         struct nfs_inode *nfsi = NFS_I(mapping->host);
1339         LIST_HEAD(head);
1340         long res;
1341
1342         spin_lock(&nfsi->req_lock);
1343         res = nfs_scan_dirty(mapping, wbc, &head);
1344         spin_unlock(&nfsi->req_lock);
1345         if (res) {
1346                 int error = nfs_flush_list(mapping->host, &head, res, how);
1347                 if (error < 0)
1348                         return error;
1349         }
1350         return res;
1351 }
1352
1353 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1354 int nfs_commit_inode(struct inode *inode, int how)
1355 {
1356         struct nfs_inode *nfsi = NFS_I(inode);
1357         LIST_HEAD(head);
1358         int res;
1359
1360         spin_lock(&nfsi->req_lock);
1361         res = nfs_scan_commit(inode, &head, 0, 0);
1362         spin_unlock(&nfsi->req_lock);
1363         if (res) {
1364                 int error = nfs_commit_list(inode, &head, how);
1365                 if (error < 0)
1366                         return error;
1367         }
1368         return res;
1369 }
1370 #endif
1371
1372 long nfs_sync_mapping_wait(struct address_space *mapping, struct writeback_control *wbc, int how)
1373 {
1374         struct inode *inode = mapping->host;
1375         struct nfs_inode *nfsi = NFS_I(inode);
1376         unsigned long idx_start, idx_end;
1377         unsigned int npages = 0;
1378         LIST_HEAD(head);
1379         int nocommit = how & FLUSH_NOCOMMIT;
1380         long pages, ret;
1381
1382         /* FIXME */
1383         if (wbc->range_cyclic)
1384                 idx_start = 0;
1385         else {
1386                 idx_start = wbc->range_start >> PAGE_CACHE_SHIFT;
1387                 idx_end = wbc->range_end >> PAGE_CACHE_SHIFT;
1388                 if (idx_end > idx_start) {
1389                         unsigned long l_npages = 1 + idx_end - idx_start;
1390                         npages = l_npages;
1391                         if (sizeof(npages) != sizeof(l_npages) &&
1392                                         (unsigned long)npages != l_npages)
1393                                 npages = 0;
1394                 }
1395         }
1396         how &= ~FLUSH_NOCOMMIT;
1397         spin_lock(&nfsi->req_lock);
1398         do {
1399                 wbc->pages_skipped = 0;
1400                 ret = nfs_wait_on_requests_locked(inode, idx_start, npages);
1401                 if (ret != 0)
1402                         continue;
1403                 pages = nfs_scan_dirty(mapping, wbc, &head);
1404                 if (pages != 0) {
1405                         spin_unlock(&nfsi->req_lock);
1406                         if (how & FLUSH_INVALIDATE) {
1407                                 nfs_cancel_dirty_list(&head);
1408                                 ret = pages;
1409                         } else
1410                                 ret = nfs_flush_list(inode, &head, pages, how);
1411                         spin_lock(&nfsi->req_lock);
1412                         continue;
1413                 }
1414                 if (wbc->pages_skipped != 0)
1415                         continue;
1416                 if (nocommit)
1417                         break;
1418                 pages = nfs_scan_commit(inode, &head, idx_start, npages);
1419                 if (pages == 0) {
1420                         if (wbc->pages_skipped != 0)
1421                                 continue;
1422                         break;
1423                 }
1424                 if (how & FLUSH_INVALIDATE) {
1425                         spin_unlock(&nfsi->req_lock);
1426                         nfs_cancel_commit_list(&head);
1427                         ret = pages;
1428                         spin_lock(&nfsi->req_lock);
1429                         continue;
1430                 }
1431                 pages += nfs_scan_commit(inode, &head, 0, 0);
1432                 spin_unlock(&nfsi->req_lock);
1433                 ret = nfs_commit_list(inode, &head, how);
1434                 spin_lock(&nfsi->req_lock);
1435         } while (ret >= 0);
1436         spin_unlock(&nfsi->req_lock);
1437         return ret;
1438 }
1439
1440 /*
1441  * flush the inode to disk.
1442  */
1443 int nfs_wb_all(struct inode *inode)
1444 {
1445         struct address_space *mapping = inode->i_mapping;
1446         struct writeback_control wbc = {
1447                 .bdi = mapping->backing_dev_info,
1448                 .sync_mode = WB_SYNC_ALL,
1449                 .nr_to_write = LONG_MAX,
1450                 .for_writepages = 1,
1451                 .range_cyclic = 1,
1452         };
1453         int ret;
1454
1455         ret = generic_writepages(mapping, &wbc);
1456         if (ret < 0)
1457                 goto out;
1458         ret = nfs_sync_mapping_wait(mapping, &wbc, 0);
1459         if (ret >= 0)
1460                 return 0;
1461 out:
1462         __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
1463         return ret;
1464 }
1465
1466 int nfs_sync_mapping_range(struct address_space *mapping, loff_t range_start, loff_t range_end, int how)
1467 {
1468         struct writeback_control wbc = {
1469                 .bdi = mapping->backing_dev_info,
1470                 .sync_mode = WB_SYNC_ALL,
1471                 .nr_to_write = LONG_MAX,
1472                 .range_start = range_start,
1473                 .range_end = range_end,
1474                 .for_writepages = 1,
1475         };
1476         int ret;
1477
1478         if (!(how & FLUSH_NOWRITEPAGE)) {
1479                 ret = generic_writepages(mapping, &wbc);
1480                 if (ret < 0)
1481                         goto out;
1482         }
1483         ret = nfs_sync_mapping_wait(mapping, &wbc, how);
1484         if (ret >= 0)
1485                 return 0;
1486 out:
1487         __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
1488         return ret;
1489 }
1490
1491 int nfs_wb_page_priority(struct inode *inode, struct page *page, int how)
1492 {
1493         loff_t range_start = page_offset(page);
1494         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1495         struct writeback_control wbc = {
1496                 .bdi = page->mapping->backing_dev_info,
1497                 .sync_mode = WB_SYNC_ALL,
1498                 .nr_to_write = LONG_MAX,
1499                 .range_start = range_start,
1500                 .range_end = range_end,
1501         };
1502         int ret;
1503
1504         BUG_ON(!PageLocked(page));
1505         if (!(how & FLUSH_NOWRITEPAGE) && clear_page_dirty_for_io(page)) {
1506                 ret = nfs_writepage_locked(page, &wbc);
1507                 if (ret < 0)
1508                         goto out;
1509         }
1510         if (!PagePrivate(page))
1511                 return 0;
1512         ret = nfs_sync_mapping_wait(page->mapping, &wbc, how);
1513         if (ret >= 0)
1514                 return 0;
1515 out:
1516         __mark_inode_dirty(inode, I_DIRTY_PAGES);
1517         return ret;
1518 }
1519
1520 /*
1521  * Write back all requests on one page - we do this before reading it.
1522  */
1523 int nfs_wb_page(struct inode *inode, struct page* page)
1524 {
1525         return nfs_wb_page_priority(inode, page, FLUSH_STABLE);
1526 }
1527
1528 int nfs_set_page_dirty(struct page *page)
1529 {
1530         struct nfs_page *req;
1531
1532         req = nfs_page_find_request(page);
1533         if (req != NULL) {
1534                 /* Mark any existing write requests for flushing */
1535                 set_bit(PG_NEED_FLUSH, &req->wb_flags);
1536                 nfs_release_request(req);
1537         }
1538         return __set_page_dirty_nobuffers(page);
1539 }
1540
1541
1542 int __init nfs_init_writepagecache(void)
1543 {
1544         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1545                                              sizeof(struct nfs_write_data),
1546                                              0, SLAB_HWCACHE_ALIGN,
1547                                              NULL, NULL);
1548         if (nfs_wdata_cachep == NULL)
1549                 return -ENOMEM;
1550
1551         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1552                                                      nfs_wdata_cachep);
1553         if (nfs_wdata_mempool == NULL)
1554                 return -ENOMEM;
1555
1556         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1557                                                       nfs_wdata_cachep);
1558         if (nfs_commit_mempool == NULL)
1559                 return -ENOMEM;
1560
1561         /*
1562          * NFS congestion size, scale with available memory.
1563          *
1564          *  64MB:    8192k
1565          * 128MB:   11585k
1566          * 256MB:   16384k
1567          * 512MB:   23170k
1568          *   1GB:   32768k
1569          *   2GB:   46340k
1570          *   4GB:   65536k
1571          *   8GB:   92681k
1572          *  16GB:  131072k
1573          *
1574          * This allows larger machines to have larger/more transfers.
1575          * Limit the default to 256M
1576          */
1577         nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1578         if (nfs_congestion_kb > 256*1024)
1579                 nfs_congestion_kb = 256*1024;
1580
1581         return 0;
1582 }
1583
1584 void nfs_destroy_writepagecache(void)
1585 {
1586         mempool_destroy(nfs_commit_mempool);
1587         mempool_destroy(nfs_wdata_mempool);
1588         kmem_cache_destroy(nfs_wdata_cachep);
1589 }
1590