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         spin_lock(&inode->i_lock);
 546         ret = nfs_scan_list(nfsi, dst, idx_start, npages, NFS_PAGE_TAG_COMMIT);
 547         if (ret > 0)
 548                 nfsi->ncommit -= ret;
 549         spin_unlock(&inode->i_lock);
 550
 551         if (nfs_need_commit(NFS_I(inode)))
 552                 __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 553
 554         return ret;
 555 }
 556 #else
 557 static inline int nfs_need_commit(struct nfs_inode *nfsi)
 558 {
 559         return 0;
 560 }
 561
 562 static inline int nfs_scan_commit(struct inode *inode, struct list_head *dst, pgoff_t idx_start, unsigned int npages)
 563 {
 564         return 0;
 565 }
 566 #endif
 567
 568 /*
 569  * Search for an existing write request, and attempt to update
 570  * it to reflect a new dirty region on a given page.
 571  *
 572  * If the attempt fails, then the existing request is flushed out
 573  * to disk.
 574  */
 575 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
 576                 struct page *page,
 577                 unsigned int offset,
 578                 unsigned int bytes)
 579 {
 580         struct nfs_page *req;
 581         unsigned int rqend;
 582         unsigned int end;
 583         int error;
 584
 585         if (!PagePrivate(page))
 586                 return NULL;
 587
 588         end = offset + bytes;
 589         spin_lock(&inode->i_lock);
 590
 591         for (;;) {
 592                 req = nfs_page_find_request_locked(page);
 593                 if (req == NULL)
 594                         goto out_unlock;
 595
 596                 rqend = req->wb_offset + req->wb_bytes;
 597                 /*
 598                  * Tell the caller to flush out the request if
 599                  * the offsets are non-contiguous.
 600                  * Note: nfs_flush_incompatible() will already
 601                  * have flushed out requests having wrong owners.
 602                  */
 603                 if (offset > rqend
 604                     || end < req->wb_offset)
 605                         goto out_flushme;
 606
 607                 if (nfs_set_page_tag_locked(req))
 608                         break;
 609
 610                 /* The request is locked, so wait and then retry */
 611                 spin_unlock(&inode->i_lock);
 612                 error = nfs_wait_on_request(req);
 613                 nfs_release_request(req);
 614                 if (error != 0)
 615                         goto out_err;
 616                 spin_lock(&inode->i_lock);
 617         }
 618
 619         if (nfs_clear_request_commit(req) &&
 620             radix_tree_tag_clear(&NFS_I(inode)->nfs_page_tree,
 621                                  req->wb_index, NFS_PAGE_TAG_COMMIT) != NULL) {
 622                 NFS_I(inode)->ncommit--;
 623                 pnfs_clear_request_commit(req);
 624         }
 625
 626         /* Okay, the request matches. Update the region */
 627         if (offset < req->wb_offset) {
 628                 req->wb_offset = offset;
 629                 req->wb_pgbase = offset;
 630         }
 631         if (end > rqend)
 632                 req->wb_bytes = end - req->wb_offset;
 633         else
 634                 req->wb_bytes = rqend - req->wb_offset;
 635 out_unlock:
 636         spin_unlock(&inode->i_lock);
 637         return req;
 638 out_flushme:
 639         spin_unlock(&inode->i_lock);
 640         nfs_release_request(req);
 641         error = nfs_wb_page(inode, page);
 642 out_err:
 643         return ERR_PTR(error);
 644 }
 645
 646 /*
 647  * Try to update an existing write request, or create one if there is none.
 648  *
 649  * Note: Should always be called with the Page Lock held to prevent races
 650  * if we have to add a new request. Also assumes that the caller has
 651  * already called nfs_flush_incompatible() if necessary.
 652  */
 653 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
 654                 struct page *page, unsigned int offset, unsigned int bytes)
 655 {
 656         struct inode *inode = page->mapping->host;
 657         struct nfs_page *req;
 658         int error;
 659
 660         req = nfs_try_to_update_request(inode, page, offset, bytes);
 661         if (req != NULL)
 662                 goto out;
 663         req = nfs_create_request(ctx, inode, page, offset, bytes);
 664         if (IS_ERR(req))
 665                 goto out;
 666         error = nfs_inode_add_request(inode, req);
 667         if (error != 0) {
 668                 nfs_release_request(req);
 669                 req = ERR_PTR(error);
 670         }
 671 out:
 672         return req;
 673 }
 674
 675 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
 676                 unsigned int offset, unsigned int count)
 677 {
 678         struct nfs_page *req;
 679
 680         req = nfs_setup_write_request(ctx, page, offset, count);
 681         if (IS_ERR(req))
 682                 return PTR_ERR(req);
 683         nfs_mark_request_dirty(req);
 684         /* Update file length */
 685         nfs_grow_file(page, offset, count);
 686         nfs_mark_uptodate(page, req->wb_pgbase, req->wb_bytes);
 687         nfs_mark_request_dirty(req);
 688         nfs_clear_page_tag_locked(req);
 689         return 0;
 690 }
 691
 692 int nfs_flush_incompatible(struct file *file, struct page *page)
 693 {
 694         struct nfs_open_context *ctx = nfs_file_open_context(file);
 695         struct nfs_page *req;
 696         int do_flush, status;
 697         /*
 698          * Look for a request corresponding to this page. If there
 699          * is one, and it belongs to another file, we flush it out
 700          * before we try to copy anything into the page. Do this
 701          * due to the lack of an ACCESS-type call in NFSv2.
 702          * Also do the same if we find a request from an existing
 703          * dropped page.
 704          */
 705         do {
 706                 req = nfs_page_find_request(page);
 707                 if (req == NULL)
 708                         return 0;
 709                 do_flush = req->wb_page != page || req->wb_context != ctx ||
 710                         req->wb_lock_context->lockowner != current->files ||
 711                         req->wb_lock_context->pid != current->tgid;
 712                 nfs_release_request(req);
 713                 if (!do_flush)
 714                         return 0;
 715                 status = nfs_wb_page(page->mapping->host, page);
 716         } while (status == 0);
 717         return status;
 718 }
 719
 720 /*
 721  * If the page cache is marked as unsafe or invalid, then we can't rely on
 722  * the PageUptodate() flag. In this case, we will need to turn off
 723  * write optimisations that depend on the page contents being correct.
 724  */
 725 static int nfs_write_pageuptodate(struct page *page, struct inode *inode)
 726 {
 727         return PageUptodate(page) &&
 728                 !(NFS_I(inode)->cache_validity & (NFS_INO_REVAL_PAGECACHE|NFS_INO_INVALID_DATA));
 729 }
 730
 731 /*
 732  * Update and possibly write a cached page of an NFS file.
 733  *
 734  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
 735  * things with a page scheduled for an RPC call (e.g. invalidate it).
 736  */
 737 int nfs_updatepage(struct file *file, struct page *page,
 738                 unsigned int offset, unsigned int count)
 739 {
 740         struct nfs_open_context *ctx = nfs_file_open_context(file);
 741         struct inode    *inode = page->mapping->host;
 742         int             status = 0;
 743
 744         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
 745
 746         dprintk("NFS:       nfs_updatepage(%s/%s %d@%lld)\n",
 747                 file->f_path.dentry->d_parent->d_name.name,
 748                 file->f_path.dentry->d_name.name, count,
 749                 (long long)(page_offset(page) + offset));
 750
 751         /* If we're not using byte range locks, and we know the page
 752          * is up to date, it may be more efficient to extend the write
 753          * to cover the entire page in order to avoid fragmentation
 754          * inefficiencies.
 755          */
 756         if (nfs_write_pageuptodate(page, inode) &&
 757                         inode->i_flock == NULL &&
 758                         !(file->f_flags & O_DSYNC)) {
 759                 count = max(count + offset, nfs_page_length(page));
 760                 offset = 0;
 761         }
 762
 763         status = nfs_writepage_setup(ctx, page, offset, count);
 764         if (status < 0)
 765                 nfs_set_pageerror(page);
 766
 767         dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
 768                         status, (long long)i_size_read(inode));
 769         return status;
 770 }
 771
 772 static void nfs_writepage_release(struct nfs_page *req,
 773                                   struct nfs_write_data *data)
 774 {
 775         struct page *page = req->wb_page;
 776
 777         if (PageError(req->wb_page) || !nfs_reschedule_unstable_write(req, data))
 778                 nfs_inode_remove_request(req);
 779         nfs_clear_page_tag_locked(req);
 780         nfs_end_page_writeback(page);
 781 }
 782
 783 static int flush_task_priority(int how)
 784 {
 785         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
 786                 case FLUSH_HIGHPRI:
 787                         return RPC_PRIORITY_HIGH;
 788                 case FLUSH_LOWPRI:
 789                         return RPC_PRIORITY_LOW;
 790         }
 791         return RPC_PRIORITY_NORMAL;
 792 }
 793
 794 int nfs_initiate_write(struct nfs_write_data *data,
 795                        struct rpc_clnt *clnt,
 796                        const struct rpc_call_ops *call_ops,
 797                        int how)
 798 {
 799         struct inode *inode = data->inode;
 800         int priority = flush_task_priority(how);
 801         struct rpc_task *task;
 802         struct rpc_message msg = {
 803                 .rpc_argp = &data->args,
 804                 .rpc_resp = &data->res,
 805                 .rpc_cred = data->cred,
 806         };
 807         struct rpc_task_setup task_setup_data = {
 808                 .rpc_client = clnt,
 809                 .task = &data->task,
 810                 .rpc_message = &msg,
 811                 .callback_ops = call_ops,
 812                 .callback_data = data,
 813                 .workqueue = nfsiod_workqueue,
 814                 .flags = RPC_TASK_ASYNC,
 815                 .priority = priority,
 816         };
 817         int ret = 0;
 818
 819         /* Set up the initial task struct.  */
 820         NFS_PROTO(inode)->write_setup(data, &msg);
 821
 822         dprintk("NFS: %5u initiated write call "
 823                 "(req %s/%lld, %u bytes @ offset %llu)\n",
 824                 data->task.tk_pid,
 825                 inode->i_sb->s_id,
 826                 (long long)NFS_FILEID(inode),
 827                 data->args.count,
 828                 (unsigned long long)data->args.offset);
 829
 830         task = rpc_run_task(&task_setup_data);
 831         if (IS_ERR(task)) {
 832                 ret = PTR_ERR(task);
 833                 goto out;
 834         }
 835         if (how & FLUSH_SYNC) {
 836                 ret = rpc_wait_for_completion_task(task);
 837                 if (ret == 0)
 838                         ret = task->tk_status;
 839         }
 840         rpc_put_task(task);
 841 out:
 842         return ret;
 843 }
 844 EXPORT_SYMBOL_GPL(nfs_initiate_write);
 845
 846 /*
 847  * Set up the argument/result storage required for the RPC call.
 848  */
 849 static int nfs_write_rpcsetup(struct nfs_page *req,
 850                 struct nfs_write_data *data,
 851                 const struct rpc_call_ops *call_ops,
 852                 unsigned int count, unsigned int offset,
 853                 struct pnfs_layout_segment *lseg,
 854                 int how)
 855 {
 856         struct inode *inode = req->wb_context->path.dentry->d_inode;
 857
 858         /* Set up the RPC argument and reply structs
 859          * NB: take care not to mess about with data->commit et al. */
 860
 861         data->req = req;
 862         data->inode = inode = req->wb_context->path.dentry->d_inode;
 863         data->cred = req->wb_context->cred;
 864         data->lseg = get_lseg(lseg);
 865
 866         data->args.fh     = NFS_FH(inode);
 867         data->args.offset = req_offset(req) + offset;
 868         data->args.pgbase = req->wb_pgbase + offset;
 869         data->args.pages  = data->pagevec;
 870         data->args.count  = count;
 871         data->args.context = get_nfs_open_context(req->wb_context);
 872         data->args.lock_context = req->wb_lock_context;
 873         data->args.stable  = NFS_UNSTABLE;
 874         if (how & (FLUSH_STABLE | FLUSH_COND_STABLE)) {
 875                 data->args.stable = NFS_DATA_SYNC;
 876                 if (!nfs_need_commit(NFS_I(inode)))
 877                         data->args.stable = NFS_FILE_SYNC;
 878         }
 879
 880         data->res.fattr   = &data->fattr;
 881         data->res.count   = count;
 882         data->res.verf    = &data->verf;
 883         nfs_fattr_init(&data->fattr);
 884
 885         if (data->lseg &&
 886             (pnfs_try_to_write_data(data, call_ops, how) == PNFS_ATTEMPTED))
 887                 return 0;
 888
 889         return nfs_initiate_write(data, NFS_CLIENT(inode), call_ops, how);
 890 }
 891
 892 /* If a nfs_flush_* function fails, it should remove reqs from @head and
 893  * call this on each, which will prepare them to be retried on next
 894  * writeback using standard nfs.
 895  */
 896 static void nfs_redirty_request(struct nfs_page *req)
 897 {
 898         struct page *page = req->wb_page;
 899
 900         nfs_mark_request_dirty(req);
 901         nfs_clear_page_tag_locked(req);
 902         nfs_end_page_writeback(page);
 903 }
 904
 905 /*
 906  * Generate multiple small requests to write out a single
 907  * contiguous dirty area on one page.
 908  */
 909 static int nfs_flush_multi(struct nfs_pageio_descriptor *desc)
 910 {
 911         struct nfs_page *req = nfs_list_entry(desc->pg_list.next);
 912         struct page *page = req->wb_page;
 913         struct nfs_write_data *data;
 914         size_t wsize = NFS_SERVER(desc->pg_inode)->wsize, nbytes;
 915         unsigned int offset;
 916         int requests = 0;
 917         int ret = 0;
 918         struct pnfs_layout_segment *lseg;
 919         LIST_HEAD(list);
 920
 921         nfs_list_remove_request(req);
 922
 923         if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
 924             (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit ||
 925              desc->pg_count > wsize))
 926                 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
 927
 928
 929         nbytes = desc->pg_count;
 930         do {
 931                 size_t len = min(nbytes, wsize);
 932
 933                 data = nfs_writedata_alloc(1);
 934                 if (!data)
 935                         goto out_bad;
 936                 list_add(&data->pages, &list);
 937                 requests++;
 938                 nbytes -= len;
 939         } while (nbytes != 0);
 940         atomic_set(&req->wb_complete, requests);
 941
 942         BUG_ON(desc->pg_lseg);
 943         lseg = pnfs_update_layout(desc->pg_inode, req->wb_context, IOMODE_RW);
 944         ClearPageError(page);
 945         offset = 0;
 946         nbytes = desc->pg_count;
 947         do {
 948                 int ret2;
 949
 950                 data = list_entry(list.next, struct nfs_write_data, pages);
 951                 list_del_init(&data->pages);
 952
 953                 data->pagevec[0] = page;
 954
 955                 if (nbytes < wsize)
 956                         wsize = nbytes;
 957                 ret2 = nfs_write_rpcsetup(req, data, &nfs_write_partial_ops,
 958                                           wsize, offset, lseg, desc->pg_ioflags);
 959                 if (ret == 0)
 960                         ret = ret2;
 961                 offset += wsize;
 962                 nbytes -= wsize;
 963         } while (nbytes != 0);
 964
 965         put_lseg(lseg);
 966         desc->pg_lseg = NULL;
 967         return ret;
 968
 969 out_bad:
 970         while (!list_empty(&list)) {
 971                 data = list_entry(list.next, struct nfs_write_data, pages);
 972                 list_del(&data->pages);
 973                 nfs_writedata_free(data);
 974         }
 975         nfs_redirty_request(req);
 976         return -ENOMEM;
 977 }
 978
 979 /*
 980  * Create an RPC task for the given write request and kick it.
 981  * The page must have been locked by the caller.
 982  *
 983  * It may happen that the page we're passed is not marked dirty.
 984  * This is the case if nfs_updatepage detects a conflicting request
 985  * that has been written but not committed.
 986  */
 987 static int nfs_flush_one(struct nfs_pageio_descriptor *desc)
 988 {
 989         struct nfs_page         *req;
 990         struct page             **pages;
 991         struct nfs_write_data   *data;
 992         struct list_head *head = &desc->pg_list;
 993         struct pnfs_layout_segment *lseg = desc->pg_lseg;
 994         int ret;
 995
 996         data = nfs_writedata_alloc(nfs_page_array_len(desc->pg_base,
 997                                                       desc->pg_count));
 998         if (!data) {
 999                 while (!list_empty(head)) {
1000                         req = nfs_list_entry(head->next);
1001                         nfs_list_remove_request(req);
1002                         nfs_redirty_request(req);
1003                 }
1004                 ret = -ENOMEM;
1005                 goto out;
1006         }
1007         pages = data->pagevec;
1008         while (!list_empty(head)) {
1009                 req = nfs_list_entry(head->next);
1010                 nfs_list_remove_request(req);
1011                 nfs_list_add_request(req, &data->pages);
1012                 ClearPageError(req->wb_page);
1013                 *pages++ = req->wb_page;
1014         }
1015         req = nfs_list_entry(data->pages.next);
1016         if ((!lseg) && list_is_singular(&data->pages))
1017                 lseg = pnfs_update_layout(desc->pg_inode, req->wb_context, IOMODE_RW);
1018
1019         if ((desc->pg_ioflags & FLUSH_COND_STABLE) &&
1020             (desc->pg_moreio || NFS_I(desc->pg_inode)->ncommit))
1021                 desc->pg_ioflags &= ~FLUSH_COND_STABLE;
1022
1023         /* Set up the argument struct */
1024         ret = nfs_write_rpcsetup(req, data, &nfs_write_full_ops, desc->pg_count, 0, lseg, desc->pg_ioflags);
1025 out:
1026         put_lseg(lseg); /* Cleans any gotten in ->pg_test */
1027         desc->pg_lseg = NULL;
1028         return ret;
1029 }
1030
1031 static void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1032                                   struct inode *inode, int ioflags)
1033 {
1034         size_t wsize = NFS_SERVER(inode)->wsize;
1035
1036         pnfs_pageio_init_write(pgio, inode);
1037
1038         if (wsize < PAGE_CACHE_SIZE)
1039                 nfs_pageio_init(pgio, inode, nfs_flush_multi, wsize, ioflags);
1040         else
1041                 nfs_pageio_init(pgio, inode, nfs_flush_one, wsize, ioflags);
1042 }
1043
1044 /*
1045  * Handle a write reply that flushed part of a page.
1046  */
1047 static void nfs_writeback_done_partial(struct rpc_task *task, void *calldata)
1048 {
1049         struct nfs_write_data   *data = calldata;
1050
1051         dprintk("NFS: %5u write(%s/%lld %d@%lld)",
1052                 task->tk_pid,
1053                 data->req->wb_context->path.dentry->d_inode->i_sb->s_id,
1054                 (long long)
1055                   NFS_FILEID(data->req->wb_context->path.dentry->d_inode),
1056                 data->req->wb_bytes, (long long)req_offset(data->req));
1057
1058         nfs_writeback_done(task, data);
1059 }
1060
1061 static void nfs_writeback_release_partial(void *calldata)
1062 {
1063         struct nfs_write_data   *data = calldata;
1064         struct nfs_page         *req = data->req;
1065         struct page             *page = req->wb_page;
1066         int status = data->task.tk_status;
1067
1068         if (status < 0) {
1069                 nfs_set_pageerror(page);
1070                 nfs_context_set_write_error(req->wb_context, status);
1071                 dprintk(", error = %d\n", status);
1072                 goto out;
1073         }
1074
1075         if (nfs_write_need_commit(data)) {
1076                 struct inode *inode = page->mapping->host;
1077
1078                 spin_lock(&inode->i_lock);
1079                 if (test_bit(PG_NEED_RESCHED, &req->wb_flags)) {
1080                         /* Do nothing we need to resend the writes */
1081                 } else if (!test_and_set_bit(PG_NEED_COMMIT, &req->wb_flags)) {
1082                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1083                         dprintk(" defer commit\n");
1084                 } else if (memcmp(&req->wb_verf, &data->verf, sizeof(req->wb_verf))) {
1085                         set_bit(PG_NEED_RESCHED, &req->wb_flags);
1086                         clear_bit(PG_NEED_COMMIT, &req->wb_flags);
1087                         dprintk(" server reboot detected\n");
1088                 }
1089                 spin_unlock(&inode->i_lock);
1090         } else
1091                 dprintk(" OK\n");
1092
1093 out:
1094         if (atomic_dec_and_test(&req->wb_complete))
1095                 nfs_writepage_release(req, data);
1096         nfs_writedata_release(calldata);
1097 }
1098
1099 #if defined(CONFIG_NFS_V4_1)
1100 void nfs_write_prepare(struct rpc_task *task, void *calldata)
1101 {
1102         struct nfs_write_data *data = calldata;
1103
1104         if (nfs4_setup_sequence(NFS_SERVER(data->inode),
1105                                 &data->args.seq_args,
1106                                 &data->res.seq_res, 1, task))
1107                 return;
1108         rpc_call_start(task);
1109 }
1110 #endif /* CONFIG_NFS_V4_1 */
1111
1112 static const struct rpc_call_ops nfs_write_partial_ops = {
1113 #if defined(CONFIG_NFS_V4_1)
1114         .rpc_call_prepare = nfs_write_prepare,
1115 #endif /* CONFIG_NFS_V4_1 */
1116         .rpc_call_done = nfs_writeback_done_partial,
1117         .rpc_release = nfs_writeback_release_partial,
1118 };
1119
1120 /*
1121  * Handle a write reply that flushes a whole page.
1122  *
1123  * FIXME: There is an inherent race with invalidate_inode_pages and
1124  *        writebacks since the page->count is kept > 1 for as long
1125  *        as the page has a write request pending.
1126  */
1127 static void nfs_writeback_done_full(struct rpc_task *task, void *calldata)
1128 {
1129         struct nfs_write_data   *data = calldata;
1130
1131         nfs_writeback_done(task, data);
1132 }
1133
1134 static void nfs_writeback_release_full(void *calldata)
1135 {
1136         struct nfs_write_data   *data = calldata;
1137         int status = data->task.tk_status;
1138
1139         /* Update attributes as result of writeback. */
1140         while (!list_empty(&data->pages)) {
1141                 struct nfs_page *req = nfs_list_entry(data->pages.next);
1142                 struct page *page = req->wb_page;
1143
1144                 nfs_list_remove_request(req);
1145
1146                 dprintk("NFS: %5u write (%s/%lld %d@%lld)",
1147                         data->task.tk_pid,
1148                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1149                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1150                         req->wb_bytes,
1151                         (long long)req_offset(req));
1152
1153                 if (status < 0) {
1154                         nfs_set_pageerror(page);
1155                         nfs_context_set_write_error(req->wb_context, status);
1156                         dprintk(", error = %d\n", status);
1157                         goto remove_request;
1158                 }
1159
1160                 if (nfs_write_need_commit(data)) {
1161                         memcpy(&req->wb_verf, &data->verf, sizeof(req->wb_verf));
1162                         nfs_mark_request_commit(req, data->lseg);
1163                         dprintk(" marked for commit\n");
1164                         goto next;
1165                 }
1166                 dprintk(" OK\n");
1167 remove_request:
1168                 nfs_inode_remove_request(req);
1169         next:
1170                 nfs_clear_page_tag_locked(req);
1171                 nfs_end_page_writeback(page);
1172         }
1173         nfs_writedata_release(calldata);
1174 }
1175
1176 static const struct rpc_call_ops nfs_write_full_ops = {
1177 #if defined(CONFIG_NFS_V4_1)
1178         .rpc_call_prepare = nfs_write_prepare,
1179 #endif /* CONFIG_NFS_V4_1 */
1180         .rpc_call_done = nfs_writeback_done_full,
1181         .rpc_release = nfs_writeback_release_full,
1182 };
1183
1184
1185 /*
1186  * This function is called when the WRITE call is complete.
1187  */
1188 void nfs_writeback_done(struct rpc_task *task, struct nfs_write_data *data)
1189 {
1190         struct nfs_writeargs    *argp = &data->args;
1191         struct nfs_writeres     *resp = &data->res;
1192         struct nfs_server       *server = NFS_SERVER(data->inode);
1193         int status;
1194
1195         dprintk("NFS: %5u nfs_writeback_done (status %d)\n",
1196                 task->tk_pid, task->tk_status);
1197
1198         /*
1199          * ->write_done will attempt to use post-op attributes to detect
1200          * conflicting writes by other clients.  A strict interpretation
1201          * of close-to-open would allow us to continue caching even if
1202          * another writer had changed the file, but some applications
1203          * depend on tighter cache coherency when writing.
1204          */
1205         status = NFS_PROTO(data->inode)->write_done(task, data);
1206         if (status != 0)
1207                 return;
1208         nfs_add_stats(data->inode, NFSIOS_SERVERWRITTENBYTES, resp->count);
1209
1210 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1211         if (resp->verf->committed < argp->stable && task->tk_status >= 0) {
1212                 /* We tried a write call, but the server did not
1213                  * commit data to stable storage even though we
1214                  * requested it.
1215                  * Note: There is a known bug in Tru64 < 5.0 in which
1216                  *       the server reports NFS_DATA_SYNC, but performs
1217                  *       NFS_FILE_SYNC. We therefore implement this checking
1218                  *       as a dprintk() in order to avoid filling syslog.
1219                  */
1220                 static unsigned long    complain;
1221
1222                 /* Note this will print the MDS for a DS write */
1223                 if (time_before(complain, jiffies)) {
1224                         dprintk("NFS:       faulty NFS server %s:"
1225                                 " (committed = %d) != (stable = %d)\n",
1226                                 server->nfs_client->cl_hostname,
1227                                 resp->verf->committed, argp->stable);
1228                         complain = jiffies + 300 * HZ;
1229                 }
1230         }
1231 #endif
1232         /* Is this a short write? */
1233         if (task->tk_status >= 0 && resp->count < argp->count) {
1234                 static unsigned long    complain;
1235
1236                 nfs_inc_stats(data->inode, NFSIOS_SHORTWRITE);
1237
1238                 /* Has the server at least made some progress? */
1239                 if (resp->count != 0) {
1240                         /* Was this an NFSv2 write or an NFSv3 stable write? */
1241                         if (resp->verf->committed != NFS_UNSTABLE) {
1242                                 /* Resend from where the server left off */
1243                                 data->mds_offset += resp->count;
1244                                 argp->offset += resp->count;
1245                                 argp->pgbase += resp->count;
1246                                 argp->count -= resp->count;
1247                         } else {
1248                                 /* Resend as a stable write in order to avoid
1249                                  * headaches in the case of a server crash.
1250                                  */
1251                                 argp->stable = NFS_FILE_SYNC;
1252                         }
1253                         nfs_restart_rpc(task, server->nfs_client);
1254                         return;
1255                 }
1256                 if (time_before(complain, jiffies)) {
1257                         printk(KERN_WARNING
1258                                "NFS: Server wrote zero bytes, expected %u.\n",
1259                                         argp->count);
1260                         complain = jiffies + 300 * HZ;
1261                 }
1262                 /* Can't do anything about it except throw an error. */
1263                 task->tk_status = -EIO;
1264         }
1265         return;
1266 }
1267
1268
1269 #if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
1270 static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait)
1271 {
1272         int ret;
1273
1274         if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags))
1275                 return 1;
1276         if (!may_wait)
1277                 return 0;
1278         ret = out_of_line_wait_on_bit_lock(&nfsi->flags,
1279                                 NFS_INO_COMMIT,
1280                                 nfs_wait_bit_killable,
1281                                 TASK_KILLABLE);
1282         return (ret < 0) ? ret : 1;
1283 }
1284
1285 void nfs_commit_clear_lock(struct nfs_inode *nfsi)
1286 {
1287         clear_bit(NFS_INO_COMMIT, &nfsi->flags);
1288         smp_mb__after_clear_bit();
1289         wake_up_bit(&nfsi->flags, NFS_INO_COMMIT);
1290 }
1291 EXPORT_SYMBOL_GPL(nfs_commit_clear_lock);
1292
1293 void nfs_commitdata_release(void *data)
1294 {
1295         struct nfs_write_data *wdata = data;
1296
1297         put_lseg(wdata->lseg);
1298         put_nfs_open_context(wdata->args.context);
1299         nfs_commit_free(wdata);
1300 }
1301 EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1302
1303 int nfs_initiate_commit(struct nfs_write_data *data, struct rpc_clnt *clnt,
1304                         const struct rpc_call_ops *call_ops,
1305                         int how)
1306 {
1307         struct rpc_task *task;
1308         int priority = flush_task_priority(how);
1309         struct rpc_message msg = {
1310                 .rpc_argp = &data->args,
1311                 .rpc_resp = &data->res,
1312                 .rpc_cred = data->cred,
1313         };
1314         struct rpc_task_setup task_setup_data = {
1315                 .task = &data->task,
1316                 .rpc_client = clnt,
1317                 .rpc_message = &msg,
1318                 .callback_ops = call_ops,
1319                 .callback_data = data,
1320                 .workqueue = nfsiod_workqueue,
1321                 .flags = RPC_TASK_ASYNC,
1322                 .priority = priority,
1323         };
1324         /* Set up the initial task struct.  */
1325         NFS_PROTO(data->inode)->commit_setup(data, &msg);
1326
1327         dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid);
1328
1329         task = rpc_run_task(&task_setup_data);
1330         if (IS_ERR(task))
1331                 return PTR_ERR(task);
1332         if (how & FLUSH_SYNC)
1333                 rpc_wait_for_completion_task(task);
1334         rpc_put_task(task);
1335         return 0;
1336 }
1337 EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1338
1339 /*
1340  * Set up the argument/result storage required for the RPC call.
1341  */
1342 void nfs_init_commit(struct nfs_write_data *data,
1343                             struct list_head *head,
1344                             struct pnfs_layout_segment *lseg)
1345 {
1346         struct nfs_page *first = nfs_list_entry(head->next);
1347         struct inode *inode = first->wb_context->path.dentry->d_inode;
1348
1349         /* Set up the RPC argument and reply structs
1350          * NB: take care not to mess about with data->commit et al. */
1351
1352         list_splice_init(head, &data->pages);
1353
1354         data->inode       = inode;
1355         data->cred        = first->wb_context->cred;
1356         data->lseg        = lseg; /* reference transferred */
1357         data->mds_ops     = &nfs_commit_ops;
1358
1359         data->args.fh     = NFS_FH(data->inode);
1360         /* Note: we always request a commit of the entire inode */
1361         data->args.offset = 0;
1362         data->args.count  = 0;
1363         data->args.context = get_nfs_open_context(first->wb_context);
1364         data->res.count   = 0;
1365         data->res.fattr   = &data->fattr;
1366         data->res.verf    = &data->verf;
1367         nfs_fattr_init(&data->fattr);
1368 }
1369 EXPORT_SYMBOL_GPL(nfs_init_commit);
1370
1371 void nfs_retry_commit(struct list_head *page_list,
1372                       struct pnfs_layout_segment *lseg)
1373 {
1374         struct nfs_page *req;
1375
1376         while (!list_empty(page_list)) {
1377                 req = nfs_list_entry(page_list->next);
1378                 nfs_list_remove_request(req);
1379                 nfs_mark_request_commit(req, lseg);
1380                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
1381                 dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
1382                              BDI_RECLAIMABLE);
1383                 nfs_clear_page_tag_locked(req);
1384         }
1385 }
1386 EXPORT_SYMBOL_GPL(nfs_retry_commit);
1387
1388 /*
1389  * Commit dirty pages
1390  */
1391 static int
1392 nfs_commit_list(struct inode *inode, struct list_head *head, int how)
1393 {
1394         struct nfs_write_data   *data;
1395
1396         data = nfs_commitdata_alloc();
1397
1398         if (!data)
1399                 goto out_bad;
1400
1401         /* Set up the argument struct */
1402         nfs_init_commit(data, head, NULL);
1403         return nfs_initiate_commit(data, NFS_CLIENT(inode), data->mds_ops, how);
1404  out_bad:
1405         nfs_retry_commit(head, NULL);
1406         nfs_commit_clear_lock(NFS_I(inode));
1407         return -ENOMEM;
1408 }
1409
1410 /*
1411  * COMMIT call returned
1412  */
1413 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1414 {
1415         struct nfs_write_data   *data = calldata;
1416
1417         dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1418                                 task->tk_pid, task->tk_status);
1419
1420         /* Call the NFS version-specific code */
1421         if (NFS_PROTO(data->inode)->commit_done(task, data) != 0)
1422                 return;
1423 }
1424
1425 void nfs_commit_release_pages(struct nfs_write_data *data)
1426 {
1427         struct nfs_page *req;
1428         int status = data->task.tk_status;
1429
1430         while (!list_empty(&data->pages)) {
1431                 req = nfs_list_entry(data->pages.next);
1432                 nfs_list_remove_request(req);
1433                 nfs_clear_request_commit(req);
1434
1435                 dprintk("NFS:       commit (%s/%lld %d@%lld)",
1436                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
1437                         (long long)NFS_FILEID(req->wb_context->path.dentry->d_inode),
1438                         req->wb_bytes,
1439                         (long long)req_offset(req));
1440                 if (status < 0) {
1441                         nfs_context_set_write_error(req->wb_context, status);
1442                         nfs_inode_remove_request(req);
1443                         dprintk(", error = %d\n", status);
1444                         goto next;
1445                 }
1446
1447                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1448                  * returned by the server against all stored verfs. */
1449                 if (!memcmp(req->wb_verf.verifier, data->verf.verifier, sizeof(data->verf.verifier))) {
1450                         /* We have a match */
1451                         nfs_inode_remove_request(req);
1452                         dprintk(" OK\n");
1453                         goto next;
1454                 }
1455                 /* We have a mismatch. Write the page again */
1456                 dprintk(" mismatch\n");
1457                 nfs_mark_request_dirty(req);
1458         next:
1459                 nfs_clear_page_tag_locked(req);
1460         }
1461 }
1462 EXPORT_SYMBOL_GPL(nfs_commit_release_pages);
1463
1464 static void nfs_commit_release(void *calldata)
1465 {
1466         struct nfs_write_data *data = calldata;
1467
1468         nfs_commit_release_pages(data);
1469         nfs_commit_clear_lock(NFS_I(data->inode));
1470         nfs_commitdata_release(calldata);
1471 }
1472
1473 static const struct rpc_call_ops nfs_commit_ops = {
1474 #if defined(CONFIG_NFS_V4_1)
1475         .rpc_call_prepare = nfs_write_prepare,
1476 #endif /* CONFIG_NFS_V4_1 */
1477         .rpc_call_done = nfs_commit_done,
1478         .rpc_release = nfs_commit_release,
1479 };
1480
1481 int nfs_commit_inode(struct inode *inode, int how)
1482 {
1483         LIST_HEAD(head);
1484         int may_wait = how & FLUSH_SYNC;
1485         int res;
1486
1487         res = nfs_commit_set_lock(NFS_I(inode), may_wait);
1488         if (res <= 0)
1489                 goto out_mark_dirty;
1490         res = nfs_scan_commit(inode, &head, 0, 0);
1491         if (res) {
1492                 int error;
1493
1494                 error = pnfs_commit_list(inode, &head, how);
1495                 if (error == PNFS_NOT_ATTEMPTED)
1496                         error = nfs_commit_list(inode, &head, how);
1497                 if (error < 0)
1498                         return error;
1499                 if (!may_wait)
1500                         goto out_mark_dirty;
1501                 error = wait_on_bit(&NFS_I(inode)->flags,
1502                                 NFS_INO_COMMIT,
1503                                 nfs_wait_bit_killable,
1504                                 TASK_KILLABLE);
1505                 if (error < 0)
1506                         return error;
1507         } else
1508                 nfs_commit_clear_lock(NFS_I(inode));
1509         return res;
1510         /* Note: If we exit without ensuring that the commit is complete,
1511          * we must mark the inode as dirty. Otherwise, future calls to
1512          * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure
1513          * that the data is on the disk.
1514          */
1515 out_mark_dirty:
1516         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1517         return res;
1518 }
1519
1520 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1521 {
1522         struct nfs_inode *nfsi = NFS_I(inode);
1523         int flags = FLUSH_SYNC;
1524         int ret = 0;
1525
1526         if (wbc->sync_mode == WB_SYNC_NONE) {
1527                 /* Don't commit yet if this is a non-blocking flush and there
1528                  * are a lot of outstanding writes for this mapping.
1529                  */
1530                 if (nfsi->ncommit <= (nfsi->npages >> 1))
1531                         goto out_mark_dirty;
1532
1533                 /* don't wait for the COMMIT response */
1534                 flags = 0;
1535         }
1536
1537         ret = nfs_commit_inode(inode, flags);
1538         if (ret >= 0) {
1539                 if (wbc->sync_mode == WB_SYNC_NONE) {
1540                         if (ret < wbc->nr_to_write)
1541                                 wbc->nr_to_write -= ret;
1542                         else
1543                                 wbc->nr_to_write = 0;
1544                 }
1545                 return 0;
1546         }
1547 out_mark_dirty:
1548         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1549         return ret;
1550 }
1551 #else
1552 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc)
1553 {
1554         return 0;
1555 }
1556 #endif
1557
1558 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1559 {
1560         int ret;
1561
1562         ret = nfs_commit_unstable_pages(inode, wbc);
1563         if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
1564                 int status;
1565                 bool sync = true;
1566
1567                 if (wbc->sync_mode == WB_SYNC_NONE || wbc->nonblocking ||
1568                     wbc->for_background)
1569                         sync = false;
1570
1571                 status = pnfs_layoutcommit_inode(inode, sync);
1572                 if (status < 0)
1573                         return status;
1574         }
1575         return ret;
1576 }
1577
1578 /*
1579  * flush the inode to disk.
1580  */
1581 int nfs_wb_all(struct inode *inode)
1582 {
1583         struct writeback_control wbc = {
1584                 .sync_mode = WB_SYNC_ALL,
1585                 .nr_to_write = LONG_MAX,
1586                 .range_start = 0,
1587                 .range_end = LLONG_MAX,
1588         };
1589
1590         return sync_inode(inode, &wbc);
1591 }
1592
1593 int nfs_wb_page_cancel(struct inode *inode, struct page *page)
1594 {
1595         struct nfs_page *req;
1596         int ret = 0;
1597
1598         BUG_ON(!PageLocked(page));
1599         for (;;) {
1600                 wait_on_page_writeback(page);
1601                 req = nfs_page_find_request(page);
1602                 if (req == NULL)
1603                         break;
1604                 if (nfs_lock_request_dontget(req)) {
1605                         nfs_inode_remove_request(req);
1606                         /*
1607                          * In case nfs_inode_remove_request has marked the
1608                          * page as being dirty
1609                          */
1610                         cancel_dirty_page(page, PAGE_CACHE_SIZE);
1611                         nfs_unlock_request(req);
1612                         break;
1613                 }
1614                 ret = nfs_wait_on_request(req);
1615                 nfs_release_request(req);
1616                 if (ret < 0)
1617                         break;
1618         }
1619         return ret;
1620 }
1621
1622 /*
1623  * Write back all requests on one page - we do this before reading it.
1624  */
1625 int nfs_wb_page(struct inode *inode, struct page *page)
1626 {
1627         loff_t range_start = page_offset(page);
1628         loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1);
1629         struct writeback_control wbc = {
1630                 .sync_mode = WB_SYNC_ALL,
1631                 .nr_to_write = 0,
1632                 .range_start = range_start,
1633                 .range_end = range_end,
1634         };
1635         int ret;
1636
1637         for (;;) {
1638                 wait_on_page_writeback(page);
1639                 if (clear_page_dirty_for_io(page)) {
1640                         ret = nfs_writepage_locked(page, &wbc);
1641                         if (ret < 0)
1642                                 goto out_error;
1643                         continue;
1644                 }
1645                 if (!PagePrivate(page))
1646                         break;
1647                 ret = nfs_commit_inode(inode, FLUSH_SYNC);
1648                 if (ret < 0)
1649                         goto out_error;
1650         }
1651         return 0;
1652 out_error:
1653         return ret;
1654 }
1655
1656 #ifdef CONFIG_MIGRATION
1657 int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
1658                 struct page *page)
1659 {
1660         struct nfs_page *req;
1661         int ret;
1662
1663         nfs_fscache_release_page(page, GFP_KERNEL);
1664
1665         req = nfs_find_and_lock_request(page, false);
1666         ret = PTR_ERR(req);
1667         if (IS_ERR(req))
1668                 goto out;
1669
1670         ret = migrate_page(mapping, newpage, page);
1671         if (!req)
1672                 goto out;
1673         if (ret)
1674                 goto out_unlock;
1675         page_cache_get(newpage);
1676         spin_lock(&mapping->host->i_lock);
1677         req->wb_page = newpage;
1678         SetPagePrivate(newpage);
1679         set_page_private(newpage, (unsigned long)req);
1680         ClearPagePrivate(page);
1681         set_page_private(page, 0);
1682         spin_unlock(&mapping->host->i_lock);
1683         page_cache_release(page);
1684 out_unlock:
1685         nfs_clear_page_tag_locked(req);
1686 out:
1687         return ret;
1688 }
1689 #endif
1690
1691 int __init nfs_init_writepagecache(void)
1692 {
1693         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
1694                                              sizeof(struct nfs_write_data),
1695                                              0, SLAB_HWCACHE_ALIGN,
1696                                              NULL);
1697         if (nfs_wdata_cachep == NULL)
1698                 return -ENOMEM;
1699
1700         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
1701                                                      nfs_wdata_cachep);
1702         if (nfs_wdata_mempool == NULL)
1703                 return -ENOMEM;
1704
1705         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
1706                                                       nfs_wdata_cachep);
1707         if (nfs_commit_mempool == NULL)
1708                 return -ENOMEM;
1709
1710         /*
1711          * NFS congestion size, scale with available memory.
1712          *
1713          *  64MB:    8192k
1714          * 128MB:   11585k
1715          * 256MB:   16384k
1716          * 512MB:   23170k
1717          *   1GB:   32768k
1718          *   2GB:   46340k
1719          *   4GB:   65536k
1720          *   8GB:   92681k
1721          *  16GB:  131072k
1722          *
1723          * This allows larger machines to have larger/more transfers.
1724          * Limit the default to 256M
1725          */
1726         nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10);
1727         if (nfs_congestion_kb > 256*1024)
1728                 nfs_congestion_kb = 256*1024;
1729
1730         return 0;
1731 }
1732
1733 void nfs_destroy_writepagecache(void)
1734 {
1735         mempool_destroy(nfs_commit_mempool);
1736         mempool_destroy(nfs_wdata_mempool);
1737         kmem_cache_destroy(nfs_wdata_cachep);
1738 }
1739