fs/nfs/write.c

   1 /*
   2  * linux/fs/nfs/write.c
   3  *
   4  * Write file data over NFS.
   5  *
   6  * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/slab.h>
  11 #include <linux/mm.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/file.h>
  14 #include <linux/writeback.h>
  15 #include <linux/swap.h>
  16 #include <linux/migrate.h>
  17
  18 #include <linux/sunrpc/clnt.h>
  19 #include <linux/nfs_fs.h>
  20 #include <linux/nfs_mount.h>
  21 #include <linux/nfs_page.h>
  22 #include <linux/backing-dev.h>
  23
  24 #include <asm/uaccess.h>
  25
  26 #include "delegation.h"
  27 #include "internal.h"
  28 #include "iostat.h"
  29 #include "nfs4_fs.h"
  30 #include "fscache.h"
  31 #include "pnfs.h"
  32
  33 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  34
  35 #define MIN_POOL_WRITE          (32)
  36 #define MIN_POOL_COMMIT         (4)
  37
  38 /*
  39  * Local function declarations
  40  */
  41 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *desc,
  42                                   struct inode *inode, int ioflags);
  43 static void nfs_redirty_request(struct nfs_page *req);
  44 static const struct rpc_call_ops nfs_write_partial_ops;
  45 static const struct rpc_call_ops nfs_write_full_ops;
  46 static const struct rpc_call_ops nfs_commit_ops;
  47
  48 static struct kmem_cache *nfs_wdata_cachep;
  49 static mempool_t *nfs_wdata_mempool;
  50 static mempool_t *nfs_commit_mempool;
  51
  52 struct nfs_write_data *nfs_commitdata_alloc(void)
  53 {
  54         struct nfs_write_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOFS);
  55
  56         if (p) {
  57                 memset(p, 0, sizeof(*p));
  58                 INIT_LIST_HEAD(&p->pages);
  59         }
  60         return p;
  61 }
  62 EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
  63
  64 void nfs_commit_free(struct nfs_write_data *p)
  65 {
  66         if (p && (p->pagevec != &p->page_array[0]))
  67                 kfree(p->pagevec);
  68         mempool_free(p, nfs_commit_mempool);
  69 }
  70 EXPORT_SYMBOL_GPL(nfs_commit_free);
  71
  72 struct nfs_write_data *nfs_writedata_alloc(unsigned int pagecount)
  73 {
  74         struct nfs_write_data *p = mempool_alloc(nfs_wdata_mempool, GFP_NOFS);
  75
  76         if (p) {
  77                 memset(p, 0, sizeof(*p));
  78                 INIT_LIST_HEAD(&p->pages);
  79                 p->npages = pagecount;
  80                 if (pagecount <= ARRAY_SIZE(p->page_array))
  81                         p->pagevec = p->page_array;
  82                 else {
  83                         p->pagevec = kcalloc(pagecount, sizeof(struct page *), GFP_NOFS);
  84                         if (!p->pagevec) {
  85                                 mempool_free(p, nfs_wdata_mempool);
  86                                 p = NULL;
  87                         }
  88                 }
  89         }
  90         return p;
  91 }
  92
  93 void nfs_writedata_free(struct nfs_write_data *p)
  94 {
  95         if (p && (p->pagevec != &p->page_array[0]))
  96                 kfree(p->pagevec);
  97         mempool_free(p, nfs_wdata_mempool);
  98 }
  99
 100 static void nfs_writedata_release(struct nfs_write_data *wdata)
 101 {
 102         put_lseg(wdata->lseg);
 103         put_nfs_open_context(wdata->args.context);
 104         nfs_writedata_free(wdata);
 105 }
 106
 107 static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
 108 {
 109         ctx->error = error;
 110         smp_wmb();
 111         set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
 112 }
 113
 114 static struct nfs_page *nfs_page_find_request_locked(struct page *page)
 115 {
 116         struct nfs_page *req = NULL;
 117
 118         if (PagePrivate(page)) {
 119                 req = (struct nfs_page *)page_private(page);
 120                 if (req != NULL)
 121                         kref_get(&req->wb_kref);
 122         }
 123         return req;
 124 }
 125
 126 static struct nfs_page *nfs_page_find_request(struct page *page)
 127 {
 128         struct inode *inode = page->mapping->host;
 129         struct nfs_page *req = NULL;
 130
 131         spin_lock(&inode->i_lock);
 132         req = nfs_page_find_request_locked(page);
 133         spin_unlock(&inode->i_lock);
 134         return req;
 135 }
 136
 137 /* Adjust the file length if we're writing beyond the end */
 138 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 139 {
 140         struct inode *inode = page->mapping->host;
 141         loff_t end, i_size;
 142         pgoff_t end_index;
 143
 144         spin_lock(&inode->i_lock);
 145         i_size = i_size_read(inode);
 146         end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
 147         if (i_size > 0 && page->index < end_index)
 148                 goto out;
 149         end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count);
 150         if (i_size >= end)
 151                 goto out;
 152         i_size_write(inode, end);
 153         nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 154 out:
 155         spin_unlock(&inode->i_lock);
 156 }
 157
 158 /* A writeback failed: mark the page as bad, and invalidate the page cache */
 159 static void nfs_set_pageerror(struct page *page)
 160 {
 161         SetPageError(page);
 162         nfs_zap_mapping(page->mapping->host, page->mapping);
 163 }
 164
 165 /* We can set the PG_uptodate flag if we see that a write request
 166  * covers the full page.
 167  */
 168 static void nfs_mark_uptodate(struct page *page, unsigned int base, unsigned int count)
 169 {
 170         if (PageUptodate(page))
 171                 return;
 172         if (base != 0)
 173                 return;
 174         if (count != nfs_page_length(page))
 175                 return;
 176         SetPageUptodate(page);
 177 }
 178
 179 static int wb_priority(struct writeback_control *wbc)
 180 {
 181         if (wbc->for_reclaim)
 182                 return FLUSH_HIGHPRI | FLUSH_STABLE;
 183         if (wbc->for_kupdate || wbc->for_background)
 184                 return FLUSH_LOWPRI | FLUSH_COND_STABLE;
 185         return FLUSH_COND_STABLE;
 186 }
 187
 188 /*
 189  * NFS congestion control
 190  */
 191
 192 int nfs_congestion_kb;
 193
 194 #define NFS_CONGESTION_ON_THRESH        (nfs_congestion_kb >> (PAGE_SHIFT-10))
 195 #define NFS_CONGESTION_OFF_THRESH       \
 196         (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 197
 198 static int nfs_set_page_writeback(struct page *page)
 199 {
 200         int ret = test_set_page_writeback(page);
 201
 202         if (!ret) {
 203                 struct inode *inode = page->mapping->host;
 204                 struct nfs_server *nfss = NFS_SERVER(inode);
 205
 206                 page_cache_get(page);
 207                 if (atomic_long_inc_return(&nfss->writeback) >
 208                                 NFS_CONGESTION_ON_THRESH) {
 209                         set_bdi_congested(&nfss->backing_dev_info,
 210                                                 BLK_RW_ASYNC);
 211                 }
 212         }
 213         return ret;
 214 }
 215
 216 static void nfs_end_page_writeback(struct page *page)
 217 {
 218         struct inode *inode = page->mapping->host;
 219         struct nfs_server *nfss = NFS_SERVER(inode);
 220
 221         end_page_writeback(page);
 222         page_cache_release(page);
 223         if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 224                 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
 225 }
 226
 227 static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblock)
 228 {
 229         struct inode *inode = page->mapping->host;
 230         struct nfs_page *req;
 231         int ret;
 232
 233         spin_lock(&inode->i_lock);
 234         for (;;) {
 235                 req = nfs_page_find_request_locked(page);
 236                 if (req == NULL)
 237                         break;
 238                 if (nfs_set_page_tag_locked(req))
 239                         break;
 240                 /* Note: If we hold the page lock, as is the case in nfs_writepage,
 241                  *       then the call to nfs_set_page_tag_locked() will always
 242                  *       succeed provided that someone hasn't already marked the
 243                  *       request as dirty (in which case we don't care).
 244                  */
 245                 spin_unlock(&inode->i_lock);
 246                 if (!nonblock)
 247                         ret = nfs_wait_on_request(req);
 248                 else
 249                         ret = -EAGAIN;
 250                 nfs_release_request(req);
 251                 if (ret != 0)
 252                         return ERR_PTR(ret);
 253                 spin_lock(&inode->i_lock);
 254         }
 255         spin_unlock(&inode->i_lock);
 256         return req;
 257 }
 258
 259 /*
 260  * Find an associated nfs write request, and prepare to flush it out
 261  * May return an error if the user signalled nfs_wait_on_request().
 262  */
 263 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 264                                 struct page *page, bool nonblock)
 265 {
 266         struct nfs_page *req;
 267         int ret = 0;
 268
 269         req = nfs_find_and_lock_request(page, nonblock);
 270         if (!req)
 271                 goto out;
 272         ret = PTR_ERR(req);
 273         if (IS_ERR(req))
 274                 goto out;
 275
 276         ret = nfs_set_page_writeback(page);
 277         BUG_ON(ret != 0);
 278         BUG_ON(test_bit(PG_CLEAN, &req->wb_flags));
 279
 280         if (!nfs_pageio_add_request(pgio, req)) {
 281                 nfs_redirty_request(req);
 282                 ret = pgio->pg_error;
 283         }
 284 out:
 285         return ret;
 286 }
 287
 288 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
 289 {
 290         struct inode *inode = page->mapping->host;
 291         int ret;
 292
 293         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 294         nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1);
 295
 296         nfs_pageio_cond_complete(pgio, page->index);
 297         ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE);
 298         if (ret == -EAGAIN) {
 299                 redirty_page_for_writepage(wbc, page);
 300                 ret = 0;
 301         }
 302         return ret;
 303 }
 304
 305 /*
 306  * Write an mmapped page to the server.
 307  */
 308 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc)
 309 {
 310         struct nfs_pageio_descriptor pgio;
 311         int err;
 312
 313         nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc));
 314         err = nfs_do_writepage(page, wbc, &pgio);
 315         nfs_pageio_complete(&pgio);
 316         if (err < 0)
 317                 return err;
 318         if (pgio.pg_error < 0)
 319                 return pgio.pg_error;
 320         return 0;
 321 }
 322
 323 int nfs_writepage(struct page *page, struct writeback_control *wbc)
 324 {
 325         int ret;
 326
 327         ret = nfs_writepage_locked(page, wbc);
 328         unlock_page(page);
 329         return ret;
 330 }
 331
 332 static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
 333 {
 334         int ret;
 335
 336         ret = nfs_do_writepage(page, wbc, data);
 337         unlock_page(page);
 338         return ret;
 339 }
 340
 341 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 342 {
 343         struct inode *inode = mapping->host;
 344         unsigned long *bitlock = &NFS_I(inode)->flags;
 345         struct nfs_pageio_descriptor pgio;
 346         int err;
 347
 348         /* Stop dirtying of new pages while we sync */
 349         err = wait_on_bit_lock(bitlock, NFS_INO_FLUSHING,
 350                         nfs_wait_bit_killable, TASK_KILLABLE);
 351         if (err)
 352                 goto out_err;
 353
 354         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 355
 356         nfs_pageio_init_write(&pgio, inode, wb_priority(wbc));
 357         err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
 358         nfs_pageio_complete(&pgio);
 359
 360         clear_bit_unlock(NFS_INO_FLUSHING, bitlock);
 361         smp_mb__after_clear_bit();
 362         wake_up_bit(bitlock, NFS_INO_FLUSHING);
 363
 364         if (err < 0)
 365                 goto out_err;
 366         err = pgio.pg_error;
 367         if (err < 0)
 368                 goto out_err;
 369         return 0;
 370 out_err:
 371         return err;
 372 }
 373
 374 /*
 375  * Insert a write request into an inode
 376  */
 377 static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 378 {
 379         struct nfs_inode *nfsi = NFS_I(inode);
 380         int error;
 381
 382         error = radix_tree_preload(GFP_NOFS);
 383         if (error != 0)
 384                 goto out;
 385
 386         /* Lock the request! */
 387         nfs_lock_request_dontget(req);
 388
 389         spin_lock(&inode->i_lock);
 390         error = radix_tree_insert(&nfsi->nfs_page_tree, req->wb_index, req);
 391         BUG_ON(error);
 392         if (!nfsi->npages && nfs_have_delegation(inode, FMODE_WRITE))
 393                 nfsi->change_attr++;
 394         set_bit(PG_MAPPED, &req->wb_flags);
 395         SetPagePrivate(req->wb_page);
 396         set_page_private(req->wb_page, (unsigned long)req);
 397         nfsi->npages++;
 398         kref_get(&req->wb_kref);
 399         radix_tree_tag_set(&nfsi->nfs_page_tree, req->wb_index,
 400                                 NFS_PAGE_TAG_LOCKED);
 401         spin_unlock(&inode->i_lock);
 402         radix_tree_preload_end();
 403 out:
 404         return error;
 405 }
 406
 407 /*
 408  * Remove a write request from an inode
 409  */
 410 static void nfs_inode_remove_request(struct nfs_page *req)
 411 {
 412         struct inode *inode = req->wb_context->path.dentry->d_inode;
 413         struct nfs_inode *nfsi = NFS_I(inode);
 414
 415         BUG_ON (!NFS_WBACK_BUSY(req));
 416
 417         spin_lock(&inode->i_lock);
 418         set_page_private(req->wb_page, 0);
 419         ClearPagePrivate(req->wb_page);
 420         clear_bit(PG_MAPPED, &req->wb_flags);
 421         radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
 422         nfsi->npages--;
 423         spin_unlock(&inode->i_lock);
 424         nfs_release_request(req);
 425 }
 426
 427 static void
 428 nfs_mark_request_dirty(struct nfs_page *req)
 429 {
 430         __set_page_dirty_nobuffers(req->wb_page);
 431         __mark_inode_dirty(req->wb_page->mapping->host, I_DIRTY_DATASYNC);
 432 }
 433
 434 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 435 /*
 436  * Add a request to the inode's commit list.
 437  */
 438 static void
 439 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
 440 {
 441         struct inode *inode = req->wb_context->path.dentry->d_inode;
 442         struct nfs_inode *nfsi = NFS_I(inode);
 443
 444         spin_lock(&inode->i_lock);
 445         set_bit(PG_CLEAN, &(req)->wb_flags);
 446         radix_tree_tag_set(&nfsi->nfs_page_tree,
 447                         req->wb_index,
 448                         NFS_PAGE_TAG_COMMIT);
 449         nfsi->ncommit++;
 450         spin_unlock(&inode->i_lock);
 451         pnfs_mark_request_commit(req, lseg);
 452         inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 453         inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 454         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 455 }
 456
 457 static int
 458 nfs_clear_request_commit(struct nfs_page *req)
 459 {
 460         struct page *page = req->wb_page;
 461
 462         if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
 463                 dec_zone_page_state(page, NR_UNSTABLE_NFS);
 464                 dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 465                 return 1;
 466         }
 467         return 0;
 468 }
 469
 470 static inline
 471 int nfs_write_need_commit(struct nfs_write_data *data)
 472 {
 473         if (data->verf.committed == NFS_DATA_SYNC)
 474                 return data->lseg == NULL;
 475         else
 476                 return data->verf.committed != NFS_FILE_SYNC;
 477 }
 478
 479 static inline
 480 int nfs_reschedule_unstable_write(struct nfs_page *req,
 481                                   struct nfs_write_data *data)
 482 {
 483         if (test_and_clear_bit(PG_NEED_COMMIT, &req->wb_flags)) {
 484                 nfs_mark_request_commit(req, data->lseg);
 485                 return 1;
 486         }
 487         if (test_and_clear_bit(PG_NEED_RESCHED, &req->wb_flags)) {
 488                 nfs_mark_request_dirty(req);
 489                 return 1;
 490         }
 491         return 0;
 492 }
 493 #else
 494 static inline void
 495 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg)
 496 {
 497 }
 498
 499 static inline int
 500 nfs_clear_request_commit(struct nfs_page *req)
 501 {
 502         return 0;
 503 }
 504
 505 static inline
 506 int nfs_write_need_commit(struct nfs_write_data *data)
 507 {
 508         return 0;
 509 }
 510
 511 static inline
 512 int nfs_reschedule_unstable_write(struct nfs_page *req,
 513                                   struct nfs_write_data *data)
 514 {
 515         return 0;
 516 }
 517 #endif
 518
 519 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
 520 static int
 521 nfs_need_commit(struct nfs_inode *nfsi)
 522 {
 523         return radix_tree_tagged(&nfsi->nfs_page_tree, NFS_PAGE_TAG_COMMIT);
 524 }
 525
 526 /*
 527  * nfs_scan_commit - Scan an inode for commit requests
 528  * @inode: NFS inode to scan
 529  * @dst: destination list
 530  * @idx_start: lower bound of page->index to scan.
 531  * @npages: idx_start + npages sets the upper bound to scan.
 532  *
 533  * Moves requests from the inode's 'commit' request list.
 534  * The requests are *not* checked to ensure that they form a contiguous set.
 535  */
 536 static int
 537 nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 538 {
 539         struct nfs_inode *nfsi = NFS_I(inode);
 540         int ret;
 541
 542         if (!nfs_need_commit(nfsi))
 543                 return 0;
 544
 545         ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
 546         if (ret > 0)
 547                 nfsi->ncommit -= ret;
 548         if (nfs_need_commit(NFS_I(inode)))
 549                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 550         return ret;
 551 }
 552 #else
 553 static inline int nfs_need_commit(struct nfs_inode *nfsi)
 554 {
 555         return 0;
 556 }
 557
 558 static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 559 {
 560         return 0;
 561 }
 562 #endif
 563
 564 /*
 565  * Search for an existing write request, and attempt to update
 566  * it to reflect a new dirty region on a given page.
 567  *
 568  * If the attempt fails, then the existing request is flushed out
 569  * to disk.
 570  */
 571 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
 572                 struct page *page,
 573                 unsigned int offset,
 574                 unsigned int bytes)
 575 {
 576         struct nfs_page *req;
 577         unsigned int rqend;
 578         unsigned int end;
 579         int error;
 580
 581         if (!PagePrivate(page))
 582                 return NULL;
 583
 584         end = offset + bytes;
 585         spin_lock(&inode->i_lock);
 586
 587         for (;;) {
 588                 req = nfs_page_find_request_locked(page);
 589                 if (req == NULL)
 590                         goto out_unlock;
 591
 592                 rqend = req->wb_offset + req->wb_bytes;
 593                 /*
 594                  * Tell the caller to flush out the request if
 595                  * the offsets are non-contiguous.
 596                  * Note: nfs_flush_incompatible() will already
 597                  * have flushed out requests having wrong owners.
 598                  */
 599                 if (offset > rqend
 600                     || end < req->wb_offset)
 601                         goto out_flushme;
 602
 603                 if (nfs_set_page_tag_locked(req))
 604                         break;
 605
 606                 /* The request is locked, so wait and then retry */
 607                 spin_unlock(&inode->i_lock);
 608                 error = nfs_wait_on_request(req);
 609                 nfs_release_request(req);
 610                 if (error != 0)
 611                         goto out_err;
 612                 spin_lock(&inode->i_lock);
 613         }
 614
 615         if (nfs_clear_request_commit(req) &&
 616             radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
 617                                  req->wb_index, NFS_PAGE_TAG_COMMIT) != NULL) {
 618                 NFS_I(inode)->ncommit--;
 619                 pnfs_clear_request_commit(req);
 620         }
 621
 622         /* Okay, the request matches. Update the region */
 623         if (offset < req->wb_offset) {
 624                 req->wb_offset = offset;
 625                 req->wb_pgbase = offset;
 626         }
 627         if (end > rqend)
 628                 req->wb_bytes = end - req->wb_offset;
 629         else
 630                 req->wb_bytes = rqend - req->wb_offset;
 631 out_unlock:
 632         spin_unlock(&inode->i_lock);
 633         return req;
 634 out_flushme:
 635         spin_unlock(&inode->i_lock);
 636         nfs_release_request(req);
 637         error = nfs_wb_page(inode, page);
 638 out_err:
 639         return ERR_PTR(error);
 640 }
 641
 642 /*
 643  * Try to update an existing write request, or create one if there is none.
 644  *
 645  * Note: Should always be called with the Page Lock held to prevent races
 646  * if we have to add a new request. Also assumes that the caller has
 647  * already called nfs_flush_incompatible() if necessary.
 648  */
 649 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
 650                 struct page *page, unsigned int offset, unsigned int bytes)
 651 {
 652         struct inode *inode = page->mapping->host;
 653         struct nfs_page *req;
 654         int error;
 655
 656         req = nfs_try_to_update_request(inode, page, offset, bytes);
 657         if (req != NULL)
 658                 goto out;
 659         req = nfs_create_request(ctx, inode, page, offset, bytes);
 660         if (IS_ERR(req))
 661                 goto out;
 662         error = nfs_inode_add_request(inode, req);
 663         if (error != 0) {
 664                 nfs_release_request(req);
 665                 req = ERR_PTR(error);
 666         }
 667 out:
 668         return req;
 669 }
 670
 671 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 672                 unsigned int offset, unsigned int count)
 673 {
 674         struct nfs_page *req;
 675
 676         req = nfs_setup_write_request(ctx, page, offset, count);
 677         if (IS_ERR(req))
 678                 return PTR_ERR(req);
 679         nfs_mark_request_dirty(req);
 680         /* Update file length */
 681         nfs_grow_file(page, offset, count);
 682         nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
 683         nfs_mark_request_dirty(req);
 684         nfs_clear_page_tag_locked(req);
 685         return 0;
 686 }
 687
 688 int nfs_flush_incompatible(struct file *file, struct page *page)
 689 {
 690         struct nfs_open_context *ctx = nfs_file_open_context(file);
 691         struct nfs_page *req;
 692         int do_flush, status;
 693         /*
 694          * Look for a request corresponding to this page. If there
 695          * is one, and it belongs to another file, we flush it out
 696          * before we try to copy anything into the page. Do this
 697          * due to the lack of an ACCESS-type call in NFSv2.
 698          * Also do the same if we find a request from an existing
 699          * dropped page.
 700          */
 701         do {
 702                 req = nfs_page_find_request(page);
 703                 if (req == NULL)
 704                         return 0;
 705                 do_flush = req->wb_page != page || req->wb_context != ctx ||
 706                         req->wb_lock_context->lockowner != current->files ||
 707                         req->wb_lock_context->pid != current->tgid;
 708                 nfs_release_request(req);
 709                 if (!do_flush)
 710                         return 0;
 711                 status = nfs_wb_page(page->mapping->host, page);
 712         } while (status == 0);
 713         return status;
 714 }
 715
 716 /*
 717  * If the page cache is marked as unsafe or invalid, then we can't rely on
 718  * the PageUptodate() flag. In this case, we will need to turn off
 719  * write optimisations that depend on the page contents being correct.
 720  */
 721 static int nfs_write_pageuptodate(struct page *page, struct inode *inode)
 722 {
 723         return PageUptodate(page) &&
 724                 !(NFS_I(inode)->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA));
 725 }
 726
 727 /*
 728  * Update and possibly write a cached page of an NFS file.
 729  *
 730  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
 731  * things with a page scheduled for an RPC call (e.g. invalidate it).
 732  */
 733 int nfs_updatepage(struct file *file, struct page *page,
 734                 unsigned int offset, unsigned int count)
 735 {
 736         struct nfs_open_context *ctx = nfs_file_open_context(file);
 737         struct inode    *inode = page->mapping->host;
 738         int             status = 0;
 739
 740         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 741
 742         dprintk("NFS:       nfs_updatepage(%s/%s %d@%lld)\n",
 743                 file->f_path.dentry->d_parent->d_name.name,
 744                 file->f_path.dentry->d_name.name, count,
 745                 (long long)(page_offset(page) + offset));
 746
 747         /* If we're not using byte range locks, and we know the page
 748          * is up to date, it may be more efficient to extend the write
 749          * to cover the entire page in order to avoid fragmentation
 750          * inefficiencies.
 751          */
 752         if (nfs_write_pageuptodate(page, inode) &&
 753                         inode->i_flock == NULL &&
 754                         !(file->f_flags & O_DSYNC)) {
 755                 count = max(count + offset, nfs_page_length(page));
 756                 offset = 0;
 757         }
 758
 759         status = nfs_writepage_setup(ctx, page, offset, count);
 760         if (status < 0)
 761                 nfs_set_pageerror(page);
 762
 763         dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
 764                         status, (long long)i_size_read(inode));
 765         return status;
 766 }
 767
 768 static void nfs_writepage_release(struct nfs_page *req,
 769                                   struct nfs_write_data *data)
 770 {
 771         struct page *page = req->wb_page;
 772
 773         if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req, data))
 774                 nfs_inode_remove_request(req);
 775         nfs_clear_page_tag_locked(req);
 776         nfs_end_page_writeback(page);
 777 }
 778
 779 static int flush_task_priority(int how)
 780 {
 781         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
 782                 case FLUSH_HIGHPRI:
 783                         return RPC_PRIORITY_HIGH;
 784                 case FLUSH_LOWPRI:
 785                         return RPC_PRIORITY_LOW;
 786         }
 787         return RPC_PRIORITY_NORMAL;
 788 }
 789
 790 int nfs_initiate_write(struct nfs_write_data *data,
 791                        struct rpc_clnt *clnt,
 792                        const struct rpc_call_ops *call_ops,
 793                        int how)
 794 {
 795         struct inode *inode = data->inode;
 796         int priority = flush_task_priority(how);
 797         struct rpc_task *task;
 798         struct rpc_message msg = {
 799                 .rpc_argp = &data->args,
 800                 .rpc_resp = &data->res,
 801                 .rpc_cred = data->cred,
 802         };
 803         struct rpc_task_setup task_setup_data = {
 804                 .rpc_client = clnt,
 805                 .task = &data->task,
 806                 .rpc_message = &msg,
 807                 .callback_ops = call_ops,
 808                 .callback_data = data,
 809                 .workqueue = nfsiod_workqueue,
 810                 .flags = RPC_TASK_ASYNC,
 811                 .priority = priority,
 812         };
 813         int ret = 0;
 814
 815         /* Set up the initial task struct.  */
 816         NFS_PROTO(inode)->write_setup(data, &msg);
 817
 818         dprintk("NFS: %5u initiated write call "
 819                 "(req %s/%lld, %u bytes @ offset %llu)\n",
 820                 data->task.tk_pid,
 821                 inode->i_sb->s_id,
 822                 (long long)NFS_FILEID(inode),
 823                 data->args.count,
 824                 (unsigned long long)data->args.offset);
 825
 826         task = rpc_run_task(&task_setup_data);
 827         if (IS_ERR(task)) {
 828                 ret = PTR_ERR(task);
 829                 goto out;
 830         }
 831         if (how & FLUSH_SYNC) {
 832                 ret = rpc_wait_for_completion_task(task);
 833                 if (ret == 0)
 834                         ret = task->tk_status;
 835         }
 836         rpc_put_task(task);
 837 out:
 838         return ret;
 839 }
 840 EXPORT_SYMBOL_GPL(nfs_initiate_write);
 841
 842 /*
 843  * Set up the argument/result storage required for the RPC call.
 844  */
 845 static int nfs_write_rpcsetup(struct nfs_page *req,
 846                 struct nfs_write_data *data,
 847                 const struct rpc_call_ops *call_ops,
 848                 unsigned int count, unsigned int offset,
 849                 struct pnfs_layout_segment *lseg,
 850                 int how)
 851 {
 852         struct inode *inode = req->wb_context->path.dentry->d_inode;
 853
 854         /* Set up the RPC argument and reply structs
 855          * NB: take care not to mess about with data->commit et al. */
 856
 857         data->req = req;
 858         data->inode = inode = req->wb_context->path.dentry->d_inode;
 859         data->cred = req->wb_context->cred;
 860         data->lseg = get_lseg(lseg);
 861
 862         data->args.fh     = NFS_FH(inode);
 863         data->args.offset = req_offset(req) + offset;
 864         data->args.pgbase = req->wb_pgbase + offset;
 865         data->args.pages  = data->pagevec;
 866         data->args.count  = count;
 867         data->args.context = get_nfs_open_context(req->wb_context);
 868         data->args.lock_context = req->wb_lock_context;
 869         data->args.stable  = NFS_UNSTABLE;
 870         if (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
 871                 data->args.stable = NFS_DATA_SYNC;
 872                 if (!nfs_need_commit(NFS_I(inode)))
 873                         data->args.stable = NFS_FILE_SYNC;
 874         }
 875
 876         data->res.fattr   = &data->fattr;
 877         data->res.count   = count;
 878         data->res.verf    = &data->verf;
 879         nfs_fattr_init(&data->fattr);
 880
 881         if (data->lseg &&
 882             (pnfs_try_to_write_data(data, call_ops, how) == PNFS_ATTEMPTED))
 883                 return 0;
 884
 885         return nfs_initiate_write(data, NFS_CLIENT(inode), call_ops, how);
 886 }
 887
 888 /* If a nfs_flush_* function fails, it should remove reqs from @head and
 889  * call this on each, which will prepare them to be retried on next
 890  * writeback using standard nfs.
 891  */
 892 static void nfs_redirty_request(struct nfs_page *req)
 893 {
 894         struct page *page = req->wb_page;
 895
 896         nfs_mark_request_dirty(req);
 897         nfs_clear_page_tag_locked(req);
 898         nfs_end_page_writeback(page);
 899 }
 900
 901 /*
 902  * Generate multiple small requests to write out a single
 903  * contiguous dirty area on one page.
 904  */
 905 static int nfs_flush_multi(struct nfs_pageio_descriptor *desc)
 906 {
 907         struct nfs_page *req = nfs_list_entry(desc->pg_list.next);
 908         struct page *page = req->wb_page;
 909         struct nfs_write_data *data;
 910         size_t wsize = NFS_SERVER(desc->pg_inode)->wsize, nbytes;
 911         unsigned int offset;
 912         int requests = 0;
 913         int ret = 0;
 914         struct pnfs_layout_segment *lseg;
 915         LIST_HEAD(list);
 916
 917         nfs_list_remove_request(req);
 918
 919         if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
 920             (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit ||
 921              desc->pg_count > wsize))
 922                 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
 923
 924
 925         nbytes = desc->pg_count;
 926         do {
 927                 size_t len = min(nbytes, wsize);
 928
 929                 data = nfs_writedata_alloc(1);
 930                 if (!data)
 931                         goto out_bad;
 932                 list_add(&data->pages, &list);
 933                 requests++;
 934                 nbytes -= len;
 935         } while (nbytes != 0);
 936         atomic_set(&req->wb_complete, requests);
 937
 938         BUG_ON(desc->pg_lseg);
 939         lseg = pnfs_update_layout(desc->pg_inode, req->wb_context, IOMODE_RW);
 940         ClearPageError(page);
 941         offset = 0;
 942         nbytes = desc->pg_count;
 943         do {
 944                 int ret2;
 945
 946                 data = list_entry(list.next, struct nfs_write_data, pages);
 947                 list_del_init(&data->pages);
 948
 949                 data->pagevec[0] = page;
 950
 951                 if (nbytes < wsize)
 952                         wsize = nbytes;
 953                 ret2 = nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
 954                                           wsize, offset, lseg, desc->pg_ioflags);
 955                 if (ret == 0)
 956                         ret = ret2;
 957                 offset += wsize;
 958                 nbytes -= wsize;
 959         } while (nbytes != 0);
 960
 961         put_lseg(lseg);
 962         desc->pg_lseg = NULL;
 963         return ret;
 964
 965 out_bad:
 966         while (!list_empty(&list)) {
 967                 data = list_entry(list.next, struct nfs_write_data, pages);
 968                 list_del(&data->pages);
 969                 nfs_writedata_free(data);
 970         }
 971         nfs_redirty_request(req);
 972         return -ENOMEM;
 973 }
 974
 975 /*
 976  * Create an RPC task for the given write request and kick it.
 977  * The page must have been locked by the caller.
 978  *
 979  * It may happen that the page we're passed is not marked dirty.
 980  * This is the case if nfs_updatepage detects a conflicting request
 981  * that has been written but not committed.
 982  */
 983 static int nfs_flush_one(struct nfs_pageio_descriptor *desc)
 984 {
 985         struct nfs_page         *req;
 986         struct page             **pages;
 987         struct nfs_write_data   *data;
 988         struct list_head *head = &desc->pg_list;
 989         struct pnfs_layout_segment *lseg = desc->pg_lseg;
 990         int ret;
 991
 992         data = nfs_writedata_alloc(nfs_page_array_len(desc->pg_base,
 993                                                       desc->pg_count));
 994         if (!data) {
 995                 while (!list_empty(head)) {
 996                         req = nfs_list_entry(head->next);
 997                         nfs_list_remove_request(req);
 998                         nfs_redirty_request(req);
 999                 }
1000                 ret = -ENOMEM;
1001                 goto out;
1002         }
1003         pages = data->pagevec;
1004         while (!list_empty(head)) {
1005                 req = nfs_list_entry(head->next);
1006                 nfs_list_remove_request(req);
1007                 nfs_list_add_request(req, &data->pages);
1008                 ClearPageError(req->wb_page);
1009                 *pages++ = req->wb_page;
1010         }
1011         req = nfs_list_entry(data->pages.next);
1012         if ((!lseg) && list_is_singular(&data->pages))
1013                 lseg = pnfs_update_layout(desc->pg_inode, req->wb_context, IOMODE_RW);
1014
1015         if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1016             (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit))
1017                 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1018
1019         /* Set up the argument struct */
1020         ret = nfs_write_rpcsetup(req, data, &nfs_write_full_ops, desc->pg_count, 0, lseg, desc->pg_ioflags);
1021 out:
1022         put_lseg(lseg); /* Cleans any gotten in ->pg_test */
1023         desc->pg_lseg = NULL;
1024         return ret;
1025 }
1026
1027 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1028                                   struct inode *inode, int ioflags)
1029 {
1030         size_t wsize = NFS_SERVER(inode)->wsize;
1031
1032         pnfs_pageio_init_write(pgio, inode);
1033
1034         if (wsize < PAGE_CACHE_SIZE)
1035                 nfs_pageio_init(pgio, inode, nfs_flush_multi, wsize, ioflags);
1036         else
1037                 nfs_pageio_init(pgio, inode, nfs_flush_one, wsize, ioflags);
1038 }
1039
1040 /*
1041  * Handle a write reply that flushed part of a page.
1042  */
1043 static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
1044 {
1045         struct nfs_write_data   *data = calldata;
1046
1047         dprintk("NFS: %5u write(%s/%lld %d@%lld)",
1048                 task->tk_pid,
1049                 data->req->wb_context->path.dentry->d_inode->i_sb->s_id,
1050                 (long long)
1051                   NFS_FILEID(data->req->wb_context->path.dentry->d_inode),
1052                 data->req->wb_bytes, (long long)req_offset(data->req));
1053
1054         nfs_writeback_done(task, data);
1055 }
1056
1057 static void nfs_writeback_release_partial(void *calldata)
1058 {
1059         struct nfs_write_data   *data = calldata;
1060         struct nfs_page         *req = data->req;
1061         struct page             *page = req->wb_page;
1062         int status = data->task.tk_status;
1063
1064         if (status < 0) {
1065                 nfs_set_pageerror(page);
1066                 nfs_context_set_write_error(req->wb_context, status);
1067                 dprintk(", error = %d\n", status);
1068                 goto out;
1069         }
1070
1071         if (nfs_write_need_commit(data)) {
1072                 struct inode *inode = page->mapping->host;
1073
1074                 spin_lock(&inode->i_lock);
1075                 if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
1076                         /* Do nothing we need to resend the writes */
1077                 } else if (!test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) {
1078                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1079                         dprintk(" defer commit\n");
1080                 } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
1081                         set_bit(PG_NEED_RESCHED, &req->wb_flags);
1082                         clear_bit(PG_NEED_COMMIT, &req->wb_flags);
1083                         dprintk(" server reboot detected\n");
1084                 }
1085                 spin_unlock(&inode->i_lock);
1086         } else
1087                 dprintk(" OK\n");
1088
1089 out:
1090         if (atomic_dec_and_test(&req->wb_complete))
1091                 nfs_writepage_release(req, data);
1092         nfs_writedata_release(calldata);
1093 }
1094
1095 #if defined(CONFIG_NFS_V4_1)
1096 void nfs_write_prepare(struct rpc_task *task, void *calldata)
1097 {
1098         struct nfs_write_data *data = calldata;
1099
1100         if (nfs4_setup_sequence(NFS_SERVER(data->inode),
1101                                 &data->args.seq_args,
1102                                 &data->res.seq_res, 1, task))
1103                 return;
1104         rpc_call_start(task);
1105 }
1106 #endif /* CONFIG_NFS_V4_1 */
1107
1108 static const struct rpc_call_ops nfs_write_partial_ops = {
1109 #if defined(CONFIG_NFS_V4_1)
1110         .rpc_call_prepare = nfs_write_prepare,
1111 #endif /* CONFIG_NFS_V4_1 */
1112         .rpc_call_done = nfs_writeback_done_partial,
1113         .rpc_release = nfs_writeback_release_partial,
1114 };
1115
1116 /*
1117  * Handle a write reply that flushes a whole page.
1118  *
1119  * FIXME: There is an inherent race with invalidate_inode_pages and
1120  *        writebacks since the page->count is kept > 1 for as long
1121  *        as the page has a write request pending.
1122  */
1123 static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
1124 {
1125         struct nfs_write_data   *data = calldata;
1126
1127         nfs_writeback_done(task, data);
1128 }
1129
1130 static void nfs_writeback_release_full(void *calldata)
1131 {
1132         struct nfs_write_data   *data = calldata;
1133         int status = data->task.tk_status;
1134
1135         /* Update attributes as result of writeback. */
1136         while (!list_empty(&data->pages)) {
1137                 struct nfs_page *req = nfs_list_entry(data->pages.next);
1138                 struct page *page = req->wb_page;
1139
1140                 nfs_list_remove_request(req);
1141
1142                 dprintk("NFS: %5u write (%s/%lld %d@%lld)",
1143                         data->task.tk_pid,
1144                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1145                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1146                         req->wb_bytes,
1147                         (long long)req_offset(req));
1148
1149                 if (status < 0) {
1150                         nfs_set_pageerror(page);
1151                         nfs_context_set_write_error(req->wb_context, status);
1152                         dprintk(", error = %d\n", status);
1153                         goto remove_request;
1154                 }
1155
1156                 if (nfs_write_need_commit(data)) {
1157                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1158                         nfs_mark_request_commit(req, data->lseg);
1159                         dprintk(" marked for commit\n");
1160                         goto next;
1161                 }
1162                 dprintk(" OK\n");
1163 remove_request:
1164                 nfs_inode_remove_request(req);
1165         next:
1166                 nfs_clear_page_tag_locked(req);
1167                 nfs_end_page_writeback(page);
1168         }
1169         nfs_writedata_release(calldata);
1170 }
1171
1172 static const struct rpc_call_ops nfs_write_full_ops = {
1173 #if defined(CONFIG_NFS_V4_1)
1174         .rpc_call_prepare = nfs_write_prepare,
1175 #endif /* CONFIG_NFS_V4_1 */
1176         .rpc_call_done = nfs_writeback_done_full,
1177         .rpc_release = nfs_writeback_release_full,
1178 };
1179
1180
1181 /*
1182  * This function is called when the WRITE call is complete.
1183  */
1184 void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1185 {
1186         struct nfs_writeargs    *argp = &data->args;
1187         struct nfs_writeres     *resp = &data->res;
1188         struct nfs_server       *server = NFS_SERVER(data->inode);
1189         int status;
1190
1191         dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1192                 task->tk_pid, task->tk_status);
1193
1194         /*
1195          * ->write_done will attempt to use post-op attributes to detect
1196          * conflicting writes by other clients.  A strict interpretation
1197          * of close-to-open would allow us to continue caching even if
1198          * another writer had changed the file, but some applications
1199          * depend on tighter cache coherency when writing.
1200          */
1201         status = NFS_PROTO(data->inode)->write_done(task, data);
1202         if (status != 0)
1203                 return;
1204         nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1205
1206 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1207         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1208                 /* We tried a write call, but the server did not
1209                  * commit data to stable storage even though we
1210                  * requested it.
1211                  * Note: There is a known bug in Tru64 < 5.0 in which
1212                  *       the server reports NFS_DATA_SYNC, but performs
1213                  *       NFS_FILE_SYNC. We therefore implement this checking
1214                  *       as a dprintk() in order to avoid filling syslog.
1215                  */
1216                 static unsigned long    complain;
1217
1218                 /* Note this will print the MDS for a DS write */
1219                 if (time_before(complain, jiffies)) {
1220                         dprintk("NFS:       faulty NFS server %s:"
1221                                 " (committed = %d) != (stable = %d)\n",
1222                                 server->nfs_client->cl_hostname,
1223                                 resp->verf->committed, argp->stable);
1224                         complain = jiffies + 300 * HZ;
1225                 }
1226         }
1227 #endif
1228         /* Is this a short write? */
1229         if (task->tk_status >= 0 && resp->count < argp->count) {
1230                 static unsigned long    complain;
1231
1232                 nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
1233
1234                 /* Has the server at least made some progress? */
1235                 if (resp->count != 0) {
1236                         /* Was this an NFSv2 write or an NFSv3 stable write? */
1237                         if (resp->verf->committed != NFS_UNSTABLE) {
1238                                 /* Resend from where the server left off */
1239                                 data->mds_offset += resp->count;
1240                                 argp->offset += resp->count;
1241                                 argp->pgbase += resp->count;
1242                                 argp->count -= resp->count;
1243                         } else {
1244                                 /* Resend as a stable write in order to avoid
1245                                  * headaches in the case of a server crash.
1246                                  */
1247                                 argp->stable = NFS_FILE_SYNC;
1248                         }
1249                         nfs_restart_rpc(task, server->nfs_client);
1250                         return;
1251                 }
1252                 if (time_before(complain, jiffies)) {
1253                         printk(KERN_WARNING
1254                                "NFS: Server wrote zero bytes, expected %u.\n",
1255                                         argp->count);
1256                         complain = jiffies + 300 * HZ;
1257                 }
1258                 /* Can't do anything about it except throw an error. */
1259                 task->tk_status = -EIO;
1260         }
1261         return;
1262 }
1263
1264
1265 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1266 static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
1267 {
1268         int ret;
1269
1270         if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
1271                 return 1;
1272         if (!may_wait)
1273                 return 0;
1274         ret = out_of_line_wait_on_bit_lock(&nfsi->flags,
1275                                 NFS_INO_COMMIT,
1276                                 nfs_wait_bit_killable,
1277                                 TASK_KILLABLE);
1278         return (ret < 0) ? ret : 1;
1279 }
1280
1281 void nfs_commit_clear_lock(struct nfs_inode *nfsi)
1282 {
1283         clear_bit(NFS_INO_COMMIT, &nfsi->flags);
1284         smp_mb__after_clear_bit();
1285         wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
1286 }
1287 EXPORT_SYMBOL_GPL(nfs_commit_clear_lock);
1288
1289 void nfs_commitdata_release(void *data)
1290 {
1291         struct nfs_write_data *wdata = data;
1292
1293         put_lseg(wdata->lseg);
1294         put_nfs_open_context(wdata->args.context);
1295         nfs_commit_free(wdata);
1296 }
1297 EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1298
1299 int nfs_initiate_commit(struct nfs_write_data *data, struct rpc_clnt *clnt,
1300                         const struct rpc_call_ops *call_ops,
1301                         int how)
1302 {
1303         struct rpc_task *task;
1304         int priority = flush_task_priority(how);
1305         struct rpc_message msg = {
1306                 .rpc_argp = &data->args,
1307                 .rpc_resp = &data->res,
1308                 .rpc_cred = data->cred,
1309         };
1310         struct rpc_task_setup task_setup_data = {
1311                 .task = &data->task,
1312                 .rpc_client = clnt,
1313                 .rpc_message = &msg,
1314                 .callback_ops = call_ops,
1315                 .callback_data = data,
1316                 .workqueue = nfsiod_workqueue,
1317                 .flags = RPC_TASK_ASYNC,
1318                 .priority = priority,
1319         };
1320         /* Set up the initial task struct.  */
1321         NFS_PROTO(data->inode)->commit_setup(data, &msg);
1322
1323         dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1324
1325         task = rpc_run_task(&task_setup_data);
1326         if (IS_ERR(task))
1327                 return PTR_ERR(task);
1328         if (how & FLUSH_SYNC)
1329                 rpc_wait_for_completion_task(task);
1330         rpc_put_task(task);
1331         return 0;
1332 }
1333 EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1334
1335 /*
1336  * Set up the argument/result storage required for the RPC call.
1337  */
1338 void nfs_init_commit(struct nfs_write_data *data,
1339                             struct list_head *head,
1340                             struct pnfs_layout_segment *lseg)
1341 {
1342         struct nfs_page *first = nfs_list_entry(head->next);
1343         struct inode *inode = first->wb_context->path.dentry->d_inode;
1344
1345         /* Set up the RPC argument and reply structs
1346          * NB: take care not to mess about with data->commit et al. */
1347
1348         list_splice_init(head, &data->pages);
1349
1350         data->inode       = inode;
1351         data->cred        = first->wb_context->cred;
1352         data->lseg        = lseg; /* reference transferred */
1353         data->mds_ops     = &nfs_commit_ops;
1354
1355         data->args.fh     = NFS_FH(data->inode);
1356         /* Note: we always request a commit of the entire inode */
1357         data->args.offset = 0;
1358         data->args.count  = 0;
1359         data->args.context = get_nfs_open_context(first->wb_context);
1360         data->res.count   = 0;
1361         data->res.fattr   = &data->fattr;
1362         data->res.verf    = &data->verf;
1363         nfs_fattr_init(&data->fattr);
1364 }
1365 EXPORT_SYMBOL_GPL(nfs_init_commit);
1366
1367 void nfs_retry_commit(struct list_head *page_list,
1368                       struct pnfs_layout_segment *lseg)
1369 {
1370         struct nfs_page *req;
1371
1372         while (!list_empty(page_list)) {
1373                 req = nfs_list_entry(page_list->next);
1374                 nfs_list_remove_request(req);
1375                 nfs_mark_request_commit(req, lseg);
1376                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1377                 dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
1378                              BDI_RECLAIMABLE);
1379                 nfs_clear_page_tag_locked(req);
1380         }
1381 }
1382 EXPORT_SYMBOL_GPL(nfs_retry_commit);
1383
1384 /*
1385  * Commit dirty pages
1386  */
1387 static int
1388 nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1389 {
1390         struct nfs_write_data   *data;
1391
1392         data = nfs_commitdata_alloc();
1393
1394         if (!data)
1395                 goto out_bad;
1396
1397         /* Set up the argument struct */
1398         nfs_init_commit(data, head, NULL);
1399         return nfs_initiate_commit(data, NFS_CLIENT(inode), data->mds_ops, how);
1400  out_bad:
1401         nfs_retry_commit(head, NULL);
1402         nfs_commit_clear_lock(NFS_I(inode));
1403         return -ENOMEM;
1404 }
1405
1406 /*
1407  * COMMIT call returned
1408  */
1409 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1410 {
1411         struct nfs_write_data   *data = calldata;
1412
1413         dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1414                                 task->tk_pid, task->tk_status);
1415
1416         /* Call the NFS version-specific code */
1417         if (NFS_PROTO(data->inode)->commit_done(task, data) != 0)
1418                 return;
1419 }
1420
1421 void nfs_commit_release_pages(struct nfs_write_data *data)
1422 {
1423         struct nfs_page *req;
1424         int status = data->task.tk_status;
1425
1426         while (!list_empty(&data->pages)) {
1427                 req = nfs_list_entry(data->pages.next);
1428                 nfs_list_remove_request(req);
1429                 nfs_clear_request_commit(req);
1430
1431                 dprintk("NFS:       commit (%s/%lld %d@%lld)",
1432                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1433                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1434                         req->wb_bytes,
1435                         (long long)req_offset(req));
1436                 if (status < 0) {
1437                         nfs_context_set_write_error(req->wb_context, status);
1438                         nfs_inode_remove_request(req);
1439                         dprintk(", error = %d\n", status);
1440                         goto next;
1441                 }
1442
1443                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1444                  * returned by the server against all stored verfs. */
1445                 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1446                         /* We have a match */
1447                         nfs_inode_remove_request(req);
1448                         dprintk(" OK\n");
1449                         goto next;
1450                 }
1451                 /* We have a mismatch. Write the page again */
1452                 dprintk(" mismatch\n");
1453                 nfs_mark_request_dirty(req);
1454         next:
1455                 nfs_clear_page_tag_locked(req);
1456         }
1457 }
1458 EXPORT_SYMBOL_GPL(nfs_commit_release_pages);
1459
1460 static void nfs_commit_release(void *calldata)
1461 {
1462         struct nfs_write_data *data = calldata;
1463
1464         nfs_commit_release_pages(data);
1465         nfs_commit_clear_lock(NFS_I(data->inode));
1466         nfs_commitdata_release(calldata);
1467 }
1468
1469 static const struct rpc_call_ops nfs_commit_ops = {
1470 #if defined(CONFIG_NFS_V4_1)
1471         .rpc_call_prepare = nfs_write_prepare,
1472 #endif /* CONFIG_NFS_V4_1 */
1473         .rpc_call_done = nfs_commit_done,
1474         .rpc_release = nfs_commit_release,
1475 };
1476
1477 int nfs_commit_inode(struct inode *inode, int how)
1478 {
1479         LIST_HEAD(head);
1480         int may_wait = how & FLUSH_SYNC;
1481         int res;
1482
1483         res = nfs_commit_set_lock(NFS_I(inode), may_wait);
1484         if (res <= 0)
1485                 goto out_mark_dirty;
1486         spin_lock(&inode->i_lock);
1487         res = nfs_scan_commit(inode, &head, 0, 0);
1488         spin_unlock(&inode->i_lock);
1489         if (res) {
1490                 int error;
1491
1492                 error = pnfs_commit_list(inode, &head, how);
1493                 if (error == PNFS_NOT_ATTEMPTED)
1494                         error = nfs_commit_list(inode, &head, how);
1495                 if (error < 0)
1496                         return error;
1497                 if (!may_wait)
1498                         goto out_mark_dirty;
1499                 error = wait_on_bit(&NFS_I(inode)->flags,
1500                                 NFS_INO_COMMIT,
1501                                 nfs_wait_bit_killable,
1502                                 TASK_KILLABLE);
1503                 if (error < 0)
1504                         return error;
1505         } else
1506                 nfs_commit_clear_lock(NFS_I(inode));
1507         return res;
1508         /* Note: If we exit without ensuring that the commit is complete,
1509          * we must mark the inode as dirty. Otherwise, future calls to
1510          * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
1511          * that the data is on the disk.
1512          */
1513 out_mark_dirty:
1514         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1515         return res;
1516 }
1517
1518 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1519 {
1520         struct nfs_inode *nfsi = NFS_I(inode);
1521         int flags = FLUSH_SYNC;
1522         int ret = 0;
1523
1524         if (wbc->sync_mode == WB_SYNC_NONE) {
1525                 /* Don't commit yet if this is a non-blocking flush and there
1526                  * are a lot of outstanding writes for this mapping.
1527                  */
1528                 if (nfsi->ncommit <= (nfsi->npages >> 1))
1529                         goto out_mark_dirty;
1530
1531                 /* don't wait for the COMMIT response */
1532                 flags = 0;
1533         }
1534
1535         ret = nfs_commit_inode(inode, flags);
1536         if (ret >= 0) {
1537                 if (wbc->sync_mode == WB_SYNC_NONE) {
1538                         if (ret < wbc->nr_to_write)
1539                                 wbc->nr_to_write -= ret;
1540                         else
1541                                 wbc->nr_to_write = 0;
1542                 }
1543                 return 0;
1544         }
1545 out_mark_dirty:
1546         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1547         return ret;
1548 }
1549 #else
1550 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1551 {
1552         return 0;
1553 }
1554 #endif
1555
1556 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1557 {
1558         int ret;
1559
1560         ret = nfs_commit_unstable_pages(inode, wbc);
1561         if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
1562                 int status;
1563                 bool sync = true;
1564
1565                 if (wbc->sync_mode == WB_SYNC_NONE || wbc->nonblocking ||
1566                     wbc->for_background)
1567                         sync = false;
1568
1569                 status = pnfs_layoutcommit_inode(inode, sync);
1570                 if (status < 0)
1571                         return status;
1572         }
1573         return ret;
1574 }
1575
1576 /*
1577  * flush the inode to disk.
1578  */
1579 int nfs_wb_all(struct inode *inode)
1580 {
1581         struct writeback_control wbc = {
1582                 .sync_mode = WB_SYNC_ALL,
1583                 .nr_to_write = LONG_MAX,
1584                 .range_start = 0,
1585                 .range_end = LLONG_MAX,
1586         };
1587
1588         return sync_inode(inode, &wbc);
1589 }
1590
1591 int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1592 {
1593         struct nfs_page *req;
1594         int ret = 0;
1595
1596         BUG_ON(!PageLocked(page));
1597         for (;;) {
1598                 wait_on_page_writeback(page);
1599                 req = nfs_page_find_request(page);
1600                 if (req == NULL)
1601                         break;
1602                 if (nfs_lock_request_dontget(req)) {
1603                         nfs_inode_remove_request(req);
1604                         /*
1605                          * In case nfs_inode_remove_request has marked the
1606                          * page as being dirty
1607                          */
1608                         cancel_dirty_page(page, PAGE_CACHE_SIZE);
1609                         nfs_unlock_request(req);
1610                         break;
1611                 }
1612                 ret = nfs_wait_on_request(req);
1613                 nfs_release_request(req);
1614                 if (ret < 0)
1615                         break;
1616         }
1617         return ret;
1618 }
1619
1620 /*
1621  * Write back all requests on one page - we do this before reading it.
1622  */
1623 int nfs_wb_page(struct inode *inode, struct page *page)
1624 {
1625         loff_t range_start = page_offset(page);
1626         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1627         struct writeback_control wbc = {
1628                 .sync_mode = WB_SYNC_ALL,
1629                 .nr_to_write = 0,
1630                 .range_start = range_start,
1631                 .range_end = range_end,
1632         };
1633         int ret;
1634
1635         for (;;) {
1636                 wait_on_page_writeback(page);
1637                 if (clear_page_dirty_for_io(page)) {
1638                         ret = nfs_writepage_locked(page, &wbc);
1639                         if (ret < 0)
1640                                 goto out_error;
1641                         continue;
1642                 }
1643                 if (!PagePrivate(page))
1644                         break;
1645                 ret = nfs_commit_inode(inode, FLUSH_SYNC);
1646                 if (ret < 0)
1647                         goto out_error;
1648         }
1649         return 0;
1650 out_error:
1651         return ret;
1652 }
1653
1654 #ifdef CONFIG_MIGRATION
1655 int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
1656                 struct page *page)
1657 {
1658         struct nfs_page *req;
1659         int ret;
1660
1661         nfs_fscache_release_page(page, GFP_KERNEL);
1662
1663         req = nfs_find_and_lock_request(page, false);
1664         ret = PTR_ERR(req);
1665         if (IS_ERR(req))
1666                 goto out;
1667
1668         ret = migrate_page(mapping, newpage, page);
1669         if (!req)
1670                 goto out;
1671         if (ret)
1672                 goto out_unlock;
1673         page_cache_get(newpage);
1674         spin_lock(&mapping->host->i_lock);
1675         req->wb_page = newpage;
1676         SetPagePrivate(newpage);
1677         set_page_private(newpage, (unsigned long)req);
1678         ClearPagePrivate(page);
1679         set_page_private(page, 0);
1680         spin_unlock(&mapping->host->i_lock);
1681         page_cache_release(page);
1682 out_unlock:
1683         nfs_clear_page_tag_locked(req);
1684 out:
1685         return ret;
1686 }
1687 #endif
1688
1689 int __init nfs_init_writepagecache(void)
1690 {
1691         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1692                                              sizeof(struct nfs_write_data),
1693                                              0, SLAB_HWCACHE_ALIGN,
1694                                              NULL);
1695         if (nfs_wdata_cachep == NULL)
1696                 return -ENOMEM;
1697
1698         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1699                                                      nfs_wdata_cachep);
1700         if (nfs_wdata_mempool == NULL)
1701                 return -ENOMEM;
1702
1703         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1704                                                       nfs_wdata_cachep);
1705         if (nfs_commit_mempool == NULL)
1706                 return -ENOMEM;
1707
1708         /*
1709          * NFS congestion size, scale with available memory.
1710          *
1711          *  64MB:    8192k
1712          * 128MB:   11585k
1713          * 256MB:   16384k
1714          * 512MB:   23170k
1715          *   1GB:   32768k
1716          *   2GB:   46340k
1717          *   4GB:   65536k
1718          *   8GB:   92681k
1719          *  16GB:  131072k
1720          *
1721          * This allows larger machines to have larger/more transfers.
1722          * Limit the default to 256M
1723          */
1724         nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1725         if (nfs_congestion_kb > 256*1024)
1726                 nfs_congestion_kb = 256*1024;
1727
1728         return 0;
1729 }
1730
1731 void nfs_destroy_writepagecache(void)
1732 {
1733         mempool_destroy(nfs_commit_mempool);
1734         mempool_destroy(nfs_wdata_mempool);
1735         kmem_cache_destroy(nfs_wdata_cachep);
1736 }
1737