fs/nfs/write.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/fs/nfs/write.c
   4  *
   5  * Write file data over NFS.
   6  *
   7  * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de>
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/slab.h>
  12 #include <linux/mm.h>
  13 #include <linux/pagemap.h>
  14 #include <linux/file.h>
  15 #include <linux/writeback.h>
  16 #include <linux/swap.h>
  17 #include <linux/migrate.h>
  18
  19 #include <linux/sunrpc/clnt.h>
  20 #include <linux/nfs_fs.h>
  21 #include <linux/nfs_mount.h>
  22 #include <linux/nfs_page.h>
  23 #include <linux/backing-dev.h>
  24 #include <linux/export.h>
  25 #include <linux/freezer.h>
  26 #include <linux/wait.h>
  27 #include <linux/iversion.h>
  28
  29 #include <linux/uaccess.h>
  30 #include <linux/sched/mm.h>
  31
  32 #include "delegation.h"
  33 #include "internal.h"
  34 #include "iostat.h"
  35 #include "nfs4_fs.h"
  36 #include "fscache.h"
  37 #include "pnfs.h"
  38
  39 #include "nfstrace.h"
  40
  41 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  42
  43 #define MIN_POOL_WRITE          (32)
  44 #define MIN_POOL_COMMIT         (4)
  45
  46 struct nfs_io_completion {
  47         void (*complete)(void *data);
  48         void *data;
  49         struct kref refcount;
  50 };
  51
  52 /*
  53  * Local function declarations
  54  */
  55 static void nfs_redirty_request(struct nfs_page *req);
  56 static const struct rpc_call_ops nfs_commit_ops;
  57 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
  58 static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
  59 static const struct nfs_rw_ops nfs_rw_write_ops;
  60 static void nfs_inode_remove_request(struct nfs_page *req);
  61 static void nfs_clear_request_commit(struct nfs_page *req);
  62 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
  63                                       struct inode *inode);
  64 static struct nfs_page *
  65 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
  66                                                 struct page *page);
  67
  68 static struct kmem_cache *nfs_wdata_cachep;
  69 static mempool_t *nfs_wdata_mempool;
  70 static struct kmem_cache *nfs_cdata_cachep;
  71 static mempool_t *nfs_commit_mempool;
  72
  73 struct nfs_commit_data *nfs_commitdata_alloc(void)
  74 {
  75         struct nfs_commit_data *p;
  76
  77         p = kmem_cache_zalloc(nfs_cdata_cachep, nfs_io_gfp_mask());
  78         if (!p) {
  79                 p = mempool_alloc(nfs_commit_mempool, GFP_NOWAIT);
  80                 if (!p)
  81                         return NULL;
  82                 memset(p, 0, sizeof(*p));
  83         }
  84         INIT_LIST_HEAD(&p->pages);
  85         return p;
  86 }
  87 EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
  88
  89 void nfs_commit_free(struct nfs_commit_data *p)
  90 {
  91         mempool_free(p, nfs_commit_mempool);
  92 }
  93 EXPORT_SYMBOL_GPL(nfs_commit_free);
  94
  95 static struct nfs_pgio_header *nfs_writehdr_alloc(void)
  96 {
  97         struct nfs_pgio_header *p;
  98
  99         p = kmem_cache_zalloc(nfs_wdata_cachep, nfs_io_gfp_mask());
 100         if (!p) {
 101                 p = mempool_alloc(nfs_wdata_mempool, GFP_NOWAIT);
 102                 if (!p)
 103                         return NULL;
 104                 memset(p, 0, sizeof(*p));
 105         }
 106         p->rw_mode = FMODE_WRITE;
 107         return p;
 108 }
 109
 110 static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
 111 {
 112         mempool_free(hdr, nfs_wdata_mempool);
 113 }
 114
 115 static struct nfs_io_completion *nfs_io_completion_alloc(gfp_t gfp_flags)
 116 {
 117         return kmalloc(sizeof(struct nfs_io_completion), gfp_flags);
 118 }
 119
 120 static void nfs_io_completion_init(struct nfs_io_completion *ioc,
 121                 void (*complete)(void *), void *data)
 122 {
 123         ioc->complete = complete;
 124         ioc->data = data;
 125         kref_init(&ioc->refcount);
 126 }
 127
 128 static void nfs_io_completion_release(struct kref *kref)
 129 {
 130         struct nfs_io_completion *ioc = container_of(kref,
 131                         struct nfs_io_completion, refcount);
 132         ioc->complete(ioc->data);
 133         kfree(ioc);
 134 }
 135
 136 static void nfs_io_completion_get(struct nfs_io_completion *ioc)
 137 {
 138         if (ioc != NULL)
 139                 kref_get(&ioc->refcount);
 140 }
 141
 142 static void nfs_io_completion_put(struct nfs_io_completion *ioc)
 143 {
 144         if (ioc != NULL)
 145                 kref_put(&ioc->refcount, nfs_io_completion_release);
 146 }
 147
 148 static void
 149 nfs_page_set_inode_ref(struct nfs_page *req, struct inode *inode)
 150 {
 151         if (!test_and_set_bit(PG_INODE_REF, &req->wb_flags)) {
 152                 kref_get(&req->wb_kref);
 153                 atomic_long_inc(&NFS_I(inode)->nrequests);
 154         }
 155 }
 156
 157 static int
 158 nfs_cancel_remove_inode(struct nfs_page *req, struct inode *inode)
 159 {
 160         int ret;
 161
 162         if (!test_bit(PG_REMOVE, &req->wb_flags))
 163                 return 0;
 164         ret = nfs_page_group_lock(req);
 165         if (ret)
 166                 return ret;
 167         if (test_and_clear_bit(PG_REMOVE, &req->wb_flags))
 168                 nfs_page_set_inode_ref(req, inode);
 169         nfs_page_group_unlock(req);
 170         return 0;
 171 }
 172
 173 static struct nfs_page *
 174 nfs_page_private_request(struct page *page)
 175 {
 176         if (!PagePrivate(page))
 177                 return NULL;
 178         return (struct nfs_page *)page_private(page);
 179 }
 180
 181 /*
 182  * nfs_page_find_head_request_locked - find head request associated with @page
 183  *
 184  * must be called while holding the inode lock.
 185  *
 186  * returns matching head request with reference held, or NULL if not found.
 187  */
 188 static struct nfs_page *
 189 nfs_page_find_private_request(struct page *page)
 190 {
 191         struct address_space *mapping = page_file_mapping(page);
 192         struct nfs_page *req;
 193
 194         if (!PagePrivate(page))
 195                 return NULL;
 196         spin_lock(&mapping->private_lock);
 197         req = nfs_page_private_request(page);
 198         if (req) {
 199                 WARN_ON_ONCE(req->wb_head != req);
 200                 kref_get(&req->wb_kref);
 201         }
 202         spin_unlock(&mapping->private_lock);
 203         return req;
 204 }
 205
 206 static struct nfs_page *
 207 nfs_page_find_swap_request(struct page *page)
 208 {
 209         struct inode *inode = page_file_mapping(page)->host;
 210         struct nfs_inode *nfsi = NFS_I(inode);
 211         struct nfs_page *req = NULL;
 212         if (!PageSwapCache(page))
 213                 return NULL;
 214         mutex_lock(&nfsi->commit_mutex);
 215         if (PageSwapCache(page)) {
 216                 req = nfs_page_search_commits_for_head_request_locked(nfsi,
 217                         page);
 218                 if (req) {
 219                         WARN_ON_ONCE(req->wb_head != req);
 220                         kref_get(&req->wb_kref);
 221                 }
 222         }
 223         mutex_unlock(&nfsi->commit_mutex);
 224         return req;
 225 }
 226
 227 /*
 228  * nfs_page_find_head_request - find head request associated with @page
 229  *
 230  * returns matching head request with reference held, or NULL if not found.
 231  */
 232 static struct nfs_page *nfs_page_find_head_request(struct page *page)
 233 {
 234         struct nfs_page *req;
 235
 236         req = nfs_page_find_private_request(page);
 237         if (!req)
 238                 req = nfs_page_find_swap_request(page);
 239         return req;
 240 }
 241
 242 static struct nfs_page *nfs_find_and_lock_page_request(struct page *page)
 243 {
 244         struct inode *inode = page_file_mapping(page)->host;
 245         struct nfs_page *req, *head;
 246         int ret;
 247
 248         for (;;) {
 249                 req = nfs_page_find_head_request(page);
 250                 if (!req)
 251                         return req;
 252                 head = nfs_page_group_lock_head(req);
 253                 if (head != req)
 254                         nfs_release_request(req);
 255                 if (IS_ERR(head))
 256                         return head;
 257                 ret = nfs_cancel_remove_inode(head, inode);
 258                 if (ret < 0) {
 259                         nfs_unlock_and_release_request(head);
 260                         return ERR_PTR(ret);
 261                 }
 262                 /* Ensure that nobody removed the request before we locked it */
 263                 if (head == nfs_page_private_request(page))
 264                         break;
 265                 if (PageSwapCache(page))
 266                         break;
 267                 nfs_unlock_and_release_request(head);
 268         }
 269         return head;
 270 }
 271
 272 /* Adjust the file length if we're writing beyond the end */
 273 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count)
 274 {
 275         struct inode *inode = page_file_mapping(page)->host;
 276         loff_t end, i_size;
 277         pgoff_t end_index;
 278
 279         spin_lock(&inode->i_lock);
 280         i_size = i_size_read(inode);
 281         end_index = (i_size - 1) >> PAGE_SHIFT;
 282         if (i_size > 0 && page_index(page) < end_index)
 283                 goto out;
 284         end = page_file_offset(page) + ((loff_t)offset+count);
 285         if (i_size >= end)
 286                 goto out;
 287         i_size_write(inode, end);
 288         NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;
 289         nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 290 out:
 291         spin_unlock(&inode->i_lock);
 292 }
 293
 294 /* A writeback failed: mark the page as bad, and invalidate the page cache */
 295 static void nfs_set_pageerror(struct address_space *mapping)
 296 {
 297         struct inode *inode = mapping->host;
 298
 299         nfs_zap_mapping(mapping->host, mapping);
 300         /* Force file size revalidation */
 301         spin_lock(&inode->i_lock);
 302         NFS_I(inode)->cache_validity |= NFS_INO_REVAL_FORCED |
 303                                         NFS_INO_REVAL_PAGECACHE |
 304                                         NFS_INO_INVALID_SIZE;
 305         spin_unlock(&inode->i_lock);
 306 }
 307
 308 static void nfs_mapping_set_error(struct page *page, int error)
 309 {
 310         struct address_space *mapping = page_file_mapping(page);
 311
 312         SetPageError(page);
 313         filemap_set_wb_err(mapping, error);
 314         if (mapping->host)
 315                 errseq_set(&mapping->host->i_sb->s_wb_err,
 316                            error == -ENOSPC ? -ENOSPC : -EIO);
 317         nfs_set_pageerror(mapping);
 318 }
 319
 320 /*
 321  * nfs_page_group_search_locked
 322  * @head - head request of page group
 323  * @page_offset - offset into page
 324  *
 325  * Search page group with head @head to find a request that contains the
 326  * page offset @page_offset.
 327  *
 328  * Returns a pointer to the first matching nfs request, or NULL if no
 329  * match is found.
 330  *
 331  * Must be called with the page group lock held
 332  */
 333 static struct nfs_page *
 334 nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)
 335 {
 336         struct nfs_page *req;
 337
 338         req = head;
 339         do {
 340                 if (page_offset >= req->wb_pgbase &&
 341                     page_offset < (req->wb_pgbase + req->wb_bytes))
 342                         return req;
 343
 344                 req = req->wb_this_page;
 345         } while (req != head);
 346
 347         return NULL;
 348 }
 349
 350 /*
 351  * nfs_page_group_covers_page
 352  * @head - head request of page group
 353  *
 354  * Return true if the page group with head @head covers the whole page,
 355  * returns false otherwise
 356  */
 357 static bool nfs_page_group_covers_page(struct nfs_page *req)
 358 {
 359         struct nfs_page *tmp;
 360         unsigned int pos = 0;
 361         unsigned int len = nfs_page_length(req->wb_page);
 362
 363         nfs_page_group_lock(req);
 364
 365         for (;;) {
 366                 tmp = nfs_page_group_search_locked(req->wb_head, pos);
 367                 if (!tmp)
 368                         break;
 369                 pos = tmp->wb_pgbase + tmp->wb_bytes;
 370         }
 371
 372         nfs_page_group_unlock(req);
 373         return pos >= len;
 374 }
 375
 376 /* We can set the PG_uptodate flag if we see that a write request
 377  * covers the full page.
 378  */
 379 static void nfs_mark_uptodate(struct nfs_page *req)
 380 {
 381         if (PageUptodate(req->wb_page))
 382                 return;
 383         if (!nfs_page_group_covers_page(req))
 384                 return;
 385         SetPageUptodate(req->wb_page);
 386 }
 387
 388 static int wb_priority(struct writeback_control *wbc)
 389 {
 390         int ret = 0;
 391
 392         if (wbc->sync_mode == WB_SYNC_ALL)
 393                 ret = FLUSH_COND_STABLE;
 394         return ret;
 395 }
 396
 397 /*
 398  * NFS congestion control
 399  */
 400
 401 int nfs_congestion_kb;
 402
 403 #define NFS_CONGESTION_ON_THRESH        (nfs_congestion_kb >> (PAGE_SHIFT-10))
 404 #define NFS_CONGESTION_OFF_THRESH       \
 405         (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 406
 407 static void nfs_set_page_writeback(struct page *page)
 408 {
 409         struct inode *inode = page_file_mapping(page)->host;
 410         struct nfs_server *nfss = NFS_SERVER(inode);
 411         int ret = test_set_page_writeback(page);
 412
 413         WARN_ON_ONCE(ret != 0);
 414
 415         if (atomic_long_inc_return(&nfss->writeback) >
 416                         NFS_CONGESTION_ON_THRESH)
 417                 set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 418 }
 419
 420 static void nfs_end_page_writeback(struct nfs_page *req)
 421 {
 422         struct inode *inode = page_file_mapping(req->wb_page)->host;
 423         struct nfs_server *nfss = NFS_SERVER(inode);
 424         bool is_done;
 425
 426         is_done = nfs_page_group_sync_on_bit(req, PG_WB_END);
 427         nfs_unlock_request(req);
 428         if (!is_done)
 429                 return;
 430
 431         end_page_writeback(req->wb_page);
 432         if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 433                 clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
 434 }
 435
 436 /*
 437  * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests
 438  *
 439  * @destroy_list - request list (using wb_this_page) terminated by @old_head
 440  * @old_head - the old head of the list
 441  *
 442  * All subrequests must be locked and removed from all lists, so at this point
 443  * they are only "active" in this function, and possibly in nfs_wait_on_request
 444  * with a reference held by some other context.
 445  */
 446 static void
 447 nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
 448                                  struct nfs_page *old_head,
 449                                  struct inode *inode)
 450 {
 451         while (destroy_list) {
 452                 struct nfs_page *subreq = destroy_list;
 453
 454                 destroy_list = (subreq->wb_this_page == old_head) ?
 455                                    NULL : subreq->wb_this_page;
 456
 457                 /* Note: lock subreq in order to change subreq->wb_head */
 458                 nfs_page_set_headlock(subreq);
 459                 WARN_ON_ONCE(old_head != subreq->wb_head);
 460
 461                 /* make sure old group is not used */
 462                 subreq->wb_this_page = subreq;
 463                 subreq->wb_head = subreq;
 464
 465                 clear_bit(PG_REMOVE, &subreq->wb_flags);
 466
 467                 /* Note: races with nfs_page_group_destroy() */
 468                 if (!kref_read(&subreq->wb_kref)) {
 469                         /* Check if we raced with nfs_page_group_destroy() */
 470                         if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags)) {
 471                                 nfs_page_clear_headlock(subreq);
 472                                 nfs_free_request(subreq);
 473                         } else
 474                                 nfs_page_clear_headlock(subreq);
 475                         continue;
 476                 }
 477                 nfs_page_clear_headlock(subreq);
 478
 479                 nfs_release_request(old_head);
 480
 481                 if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
 482                         nfs_release_request(subreq);
 483                         atomic_long_dec(&NFS_I(inode)->nrequests);
 484                 }
 485
 486                 /* subreq is now totally disconnected from page group or any
 487                  * write / commit lists. last chance to wake any waiters */
 488                 nfs_unlock_and_release_request(subreq);
 489         }
 490 }
 491
 492 /*
 493  * nfs_join_page_group - destroy subrequests of the head req
 494  * @head: the page used to lookup the "page group" of nfs_page structures
 495  * @inode: Inode to which the request belongs.
 496  *
 497  * This function joins all sub requests to the head request by first
 498  * locking all requests in the group, cancelling any pending operations
 499  * and finally updating the head request to cover the whole range covered by
 500  * the (former) group.  All subrequests are removed from any write or commit
 501  * lists, unlinked from the group and destroyed.
 502  */
 503 void
 504 nfs_join_page_group(struct nfs_page *head, struct inode *inode)
 505 {
 506         struct nfs_page *subreq;
 507         struct nfs_page *destroy_list = NULL;
 508         unsigned int pgbase, off, bytes;
 509
 510         pgbase = head->wb_pgbase;
 511         bytes = head->wb_bytes;
 512         off = head->wb_offset;
 513         for (subreq = head->wb_this_page; subreq != head;
 514                         subreq = subreq->wb_this_page) {
 515                 /* Subrequests should always form a contiguous range */
 516                 if (pgbase > subreq->wb_pgbase) {
 517                         off -= pgbase - subreq->wb_pgbase;
 518                         bytes += pgbase - subreq->wb_pgbase;
 519                         pgbase = subreq->wb_pgbase;
 520                 }
 521                 bytes = max(subreq->wb_pgbase + subreq->wb_bytes
 522                                 - pgbase, bytes);
 523         }
 524
 525         /* Set the head request's range to cover the former page group */
 526         head->wb_pgbase = pgbase;
 527         head->wb_bytes = bytes;
 528         head->wb_offset = off;
 529
 530         /* Now that all requests are locked, make sure they aren't on any list.
 531          * Commit list removal accounting is done after locks are dropped */
 532         subreq = head;
 533         do {
 534                 nfs_clear_request_commit(subreq);
 535                 subreq = subreq->wb_this_page;
 536         } while (subreq != head);
 537
 538         /* unlink subrequests from head, destroy them later */
 539         if (head->wb_this_page != head) {
 540                 /* destroy list will be terminated by head */
 541                 destroy_list = head->wb_this_page;
 542                 head->wb_this_page = head;
 543         }
 544
 545         nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
 546 }
 547
 548 /*
 549  * nfs_lock_and_join_requests - join all subreqs to the head req
 550  * @page: the page used to lookup the "page group" of nfs_page structures
 551  *
 552  * This function joins all sub requests to the head request by first
 553  * locking all requests in the group, cancelling any pending operations
 554  * and finally updating the head request to cover the whole range covered by
 555  * the (former) group.  All subrequests are removed from any write or commit
 556  * lists, unlinked from the group and destroyed.
 557  *
 558  * Returns a locked, referenced pointer to the head request - which after
 559  * this call is guaranteed to be the only request associated with the page.
 560  * Returns NULL if no requests are found for @page, or a ERR_PTR if an
 561  * error was encountered.
 562  */
 563 static struct nfs_page *
 564 nfs_lock_and_join_requests(struct page *page)
 565 {
 566         struct inode *inode = page_file_mapping(page)->host;
 567         struct nfs_page *head;
 568         int ret;
 569
 570         /*
 571          * A reference is taken only on the head request which acts as a
 572          * reference to the whole page group - the group will not be destroyed
 573          * until the head reference is released.
 574          */
 575         head = nfs_find_and_lock_page_request(page);
 576         if (IS_ERR_OR_NULL(head))
 577                 return head;
 578
 579         /* lock each request in the page group */
 580         ret = nfs_page_group_lock_subrequests(head);
 581         if (ret < 0) {
 582                 nfs_unlock_and_release_request(head);
 583                 return ERR_PTR(ret);
 584         }
 585
 586         nfs_join_page_group(head, inode);
 587
 588         return head;
 589 }
 590
 591 static void nfs_write_error(struct nfs_page *req, int error)
 592 {
 593         trace_nfs_write_error(req, error);
 594         nfs_mapping_set_error(req->wb_page, error);
 595         nfs_inode_remove_request(req);
 596         nfs_end_page_writeback(req);
 597         nfs_release_request(req);
 598 }
 599
 600 /*
 601  * Find an associated nfs write request, and prepare to flush it out
 602  * May return an error if the user signalled nfs_wait_on_request().
 603  */
 604 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
 605                                 struct page *page)
 606 {
 607         struct nfs_page *req;
 608         int ret = 0;
 609
 610         req = nfs_lock_and_join_requests(page);
 611         if (!req)
 612                 goto out;
 613         ret = PTR_ERR(req);
 614         if (IS_ERR(req))
 615                 goto out;
 616
 617         nfs_set_page_writeback(page);
 618         WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
 619
 620         /* If there is a fatal error that covers this write, just exit */
 621         ret = pgio->pg_error;
 622         if (nfs_error_is_fatal_on_server(ret))
 623                 goto out_launder;
 624
 625         ret = 0;
 626         if (!nfs_pageio_add_request(pgio, req)) {
 627                 ret = pgio->pg_error;
 628                 /*
 629                  * Remove the problematic req upon fatal errors on the server
 630                  */
 631                 if (nfs_error_is_fatal(ret)) {
 632                         if (nfs_error_is_fatal_on_server(ret))
 633                                 goto out_launder;
 634                 } else
 635                         ret = -EAGAIN;
 636                 nfs_redirty_request(req);
 637                 pgio->pg_error = 0;
 638         } else
 639                 nfs_add_stats(page_file_mapping(page)->host,
 640                                 NFSIOS_WRITEPAGES, 1);
 641 out:
 642         return ret;
 643 out_launder:
 644         nfs_write_error(req, ret);
 645         return 0;
 646 }
 647
 648 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc,
 649                             struct nfs_pageio_descriptor *pgio)
 650 {
 651         int ret;
 652
 653         nfs_pageio_cond_complete(pgio, page_index(page));
 654         ret = nfs_page_async_flush(pgio, page);
 655         if (ret == -EAGAIN) {
 656                 redirty_page_for_writepage(wbc, page);
 657                 ret = AOP_WRITEPAGE_ACTIVATE;
 658         }
 659         return ret;
 660 }
 661
 662 /*
 663  * Write an mmapped page to the server.
 664  */
 665 static int nfs_writepage_locked(struct page *page,
 666                                 struct writeback_control *wbc)
 667 {
 668         struct nfs_pageio_descriptor pgio;
 669         struct inode *inode = page_file_mapping(page)->host;
 670         int err;
 671
 672         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 673         nfs_pageio_init_write(&pgio, inode, 0,
 674                                 false, &nfs_async_write_completion_ops);
 675         err = nfs_do_writepage(page, wbc, &pgio);
 676         pgio.pg_error = 0;
 677         nfs_pageio_complete(&pgio);
 678         return err;
 679 }
 680
 681 int nfs_writepage(struct page *page, struct writeback_control *wbc)
 682 {
 683         int ret;
 684
 685         ret = nfs_writepage_locked(page, wbc);
 686         if (ret != AOP_WRITEPAGE_ACTIVATE)
 687                 unlock_page(page);
 688         return ret;
 689 }
 690
 691 static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data)
 692 {
 693         int ret;
 694
 695         ret = nfs_do_writepage(page, wbc, data);
 696         if (ret != AOP_WRITEPAGE_ACTIVATE)
 697                 unlock_page(page);
 698         return ret;
 699 }
 700
 701 static void nfs_io_completion_commit(void *inode)
 702 {
 703         nfs_commit_inode(inode, 0);
 704 }
 705
 706 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 707 {
 708         struct inode *inode = mapping->host;
 709         struct nfs_pageio_descriptor pgio;
 710         struct nfs_io_completion *ioc;
 711         int err;
 712
 713         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 714
 715         ioc = nfs_io_completion_alloc(GFP_KERNEL);
 716         if (ioc)
 717                 nfs_io_completion_init(ioc, nfs_io_completion_commit, inode);
 718
 719         nfs_pageio_init_write(&pgio, inode, wb_priority(wbc), false,
 720                                 &nfs_async_write_completion_ops);
 721         pgio.pg_io_completion = ioc;
 722         err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio);
 723         pgio.pg_error = 0;
 724         nfs_pageio_complete(&pgio);
 725         nfs_io_completion_put(ioc);
 726
 727         if (err < 0)
 728                 goto out_err;
 729         return 0;
 730 out_err:
 731         return err;
 732 }
 733
 734 /*
 735  * Insert a write request into an inode
 736  */
 737 static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 738 {
 739         struct address_space *mapping = page_file_mapping(req->wb_page);
 740         struct nfs_inode *nfsi = NFS_I(inode);
 741
 742         WARN_ON_ONCE(req->wb_this_page != req);
 743
 744         /* Lock the request! */
 745         nfs_lock_request(req);
 746
 747         /*
 748          * Swap-space should not get truncated. Hence no need to plug the race
 749          * with invalidate/truncate.
 750          */
 751         spin_lock(&mapping->private_lock);
 752         if (!nfs_have_writebacks(inode) &&
 753             NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
 754                 inode_inc_iversion_raw(inode);
 755         if (likely(!PageSwapCache(req->wb_page))) {
 756                 set_bit(PG_MAPPED, &req->wb_flags);
 757                 SetPagePrivate(req->wb_page);
 758                 set_page_private(req->wb_page, (unsigned long)req);
 759         }
 760         spin_unlock(&mapping->private_lock);
 761         atomic_long_inc(&nfsi->nrequests);
 762         /* this a head request for a page group - mark it as having an
 763          * extra reference so sub groups can follow suit.
 764          * This flag also informs pgio layer when to bump nrequests when
 765          * adding subrequests. */
 766         WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
 767         kref_get(&req->wb_kref);
 768 }
 769
 770 /*
 771  * Remove a write request from an inode
 772  */
 773 static void nfs_inode_remove_request(struct nfs_page *req)
 774 {
 775         struct address_space *mapping = page_file_mapping(req->wb_page);
 776         struct inode *inode = mapping->host;
 777         struct nfs_inode *nfsi = NFS_I(inode);
 778         struct nfs_page *head;
 779
 780         if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
 781                 head = req->wb_head;
 782
 783                 spin_lock(&mapping->private_lock);
 784                 if (likely(head->wb_page && !PageSwapCache(head->wb_page))) {
 785                         set_page_private(head->wb_page, 0);
 786                         ClearPagePrivate(head->wb_page);
 787                         clear_bit(PG_MAPPED, &head->wb_flags);
 788                 }
 789                 spin_unlock(&mapping->private_lock);
 790         }
 791
 792         if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) {
 793                 nfs_release_request(req);
 794                 atomic_long_dec(&nfsi->nrequests);
 795         }
 796 }
 797
 798 static void
 799 nfs_mark_request_dirty(struct nfs_page *req)
 800 {
 801         if (req->wb_page)
 802                 __set_page_dirty_nobuffers(req->wb_page);
 803 }
 804
 805 /*
 806  * nfs_page_search_commits_for_head_request_locked
 807  *
 808  * Search through commit lists on @inode for the head request for @page.
 809  * Must be called while holding the inode (which is cinfo) lock.
 810  *
 811  * Returns the head request if found, or NULL if not found.
 812  */
 813 static struct nfs_page *
 814 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
 815                                                 struct page *page)
 816 {
 817         struct nfs_page *freq, *t;
 818         struct nfs_commit_info cinfo;
 819         struct inode *inode = &nfsi->vfs_inode;
 820
 821         nfs_init_cinfo_from_inode(&cinfo, inode);
 822
 823         /* search through pnfs commit lists */
 824         freq = pnfs_search_commit_reqs(inode, &cinfo, page);
 825         if (freq)
 826                 return freq->wb_head;
 827
 828         /* Linearly search the commit list for the correct request */
 829         list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
 830                 if (freq->wb_page == page)
 831                         return freq->wb_head;
 832         }
 833
 834         return NULL;
 835 }
 836
 837 /**
 838  * nfs_request_add_commit_list_locked - add request to a commit list
 839  * @req: pointer to a struct nfs_page
 840  * @dst: commit list head
 841  * @cinfo: holds list lock and accounting info
 842  *
 843  * This sets the PG_CLEAN bit, updates the cinfo count of
 844  * number of outstanding requests requiring a commit as well as
 845  * the MM page stats.
 846  *
 847  * The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
 848  * nfs_page lock.
 849  */
 850 void
 851 nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
 852                             struct nfs_commit_info *cinfo)
 853 {
 854         set_bit(PG_CLEAN, &req->wb_flags);
 855         nfs_list_add_request(req, dst);
 856         atomic_long_inc(&cinfo->mds->ncommit);
 857 }
 858 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
 859
 860 /**
 861  * nfs_request_add_commit_list - add request to a commit list
 862  * @req: pointer to a struct nfs_page
 863  * @cinfo: holds list lock and accounting info
 864  *
 865  * This sets the PG_CLEAN bit, updates the cinfo count of
 866  * number of outstanding requests requiring a commit as well as
 867  * the MM page stats.
 868  *
 869  * The caller must _not_ hold the cinfo->lock, but must be
 870  * holding the nfs_page lock.
 871  */
 872 void
 873 nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
 874 {
 875         mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
 876         nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
 877         mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
 878         if (req->wb_page)
 879                 nfs_mark_page_unstable(req->wb_page, cinfo);
 880 }
 881 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
 882
 883 /**
 884  * nfs_request_remove_commit_list - Remove request from a commit list
 885  * @req: pointer to a nfs_page
 886  * @cinfo: holds list lock and accounting info
 887  *
 888  * This clears the PG_CLEAN bit, and updates the cinfo's count of
 889  * number of outstanding requests requiring a commit
 890  * It does not update the MM page stats.
 891  *
 892  * The caller _must_ hold the cinfo->lock and the nfs_page lock.
 893  */
 894 void
 895 nfs_request_remove_commit_list(struct nfs_page *req,
 896                                struct nfs_commit_info *cinfo)
 897 {
 898         if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
 899                 return;
 900         nfs_list_remove_request(req);
 901         atomic_long_dec(&cinfo->mds->ncommit);
 902 }
 903 EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
 904
 905 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 906                                       struct inode *inode)
 907 {
 908         cinfo->inode = inode;
 909         cinfo->mds = &NFS_I(inode)->commit_info;
 910         cinfo->ds = pnfs_get_ds_info(inode);
 911         cinfo->dreq = NULL;
 912         cinfo->completion_ops = &nfs_commit_completion_ops;
 913 }
 914
 915 void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 916                     struct inode *inode,
 917                     struct nfs_direct_req *dreq)
 918 {
 919         if (dreq)
 920                 nfs_init_cinfo_from_dreq(cinfo, dreq);
 921         else
 922                 nfs_init_cinfo_from_inode(cinfo, inode);
 923 }
 924 EXPORT_SYMBOL_GPL(nfs_init_cinfo);
 925
 926 /*
 927  * Add a request to the inode's commit list.
 928  */
 929 void
 930 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 931                         struct nfs_commit_info *cinfo, u32 ds_commit_idx)
 932 {
 933         if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
 934                 return;
 935         nfs_request_add_commit_list(req, cinfo);
 936 }
 937
 938 static void
 939 nfs_clear_page_commit(struct page *page)
 940 {
 941         dec_node_page_state(page, NR_WRITEBACK);
 942         dec_wb_stat(&inode_to_bdi(page_file_mapping(page)->host)->wb,
 943                     WB_WRITEBACK);
 944 }
 945
 946 /* Called holding the request lock on @req */
 947 static void
 948 nfs_clear_request_commit(struct nfs_page *req)
 949 {
 950         if (test_bit(PG_CLEAN, &req->wb_flags)) {
 951                 struct nfs_open_context *ctx = nfs_req_openctx(req);
 952                 struct inode *inode = d_inode(ctx->dentry);
 953                 struct nfs_commit_info cinfo;
 954
 955                 nfs_init_cinfo_from_inode(&cinfo, inode);
 956                 mutex_lock(&NFS_I(inode)->commit_mutex);
 957                 if (!pnfs_clear_request_commit(req, &cinfo)) {
 958                         nfs_request_remove_commit_list(req, &cinfo);
 959                 }
 960                 mutex_unlock(&NFS_I(inode)->commit_mutex);
 961                 nfs_clear_page_commit(req->wb_page);
 962         }
 963 }
 964
 965 int nfs_write_need_commit(struct nfs_pgio_header *hdr)
 966 {
 967         if (hdr->verf.committed == NFS_DATA_SYNC)
 968                 return hdr->lseg == NULL;
 969         return hdr->verf.committed != NFS_FILE_SYNC;
 970 }
 971
 972 static void nfs_async_write_init(struct nfs_pgio_header *hdr)
 973 {
 974         nfs_io_completion_get(hdr->io_completion);
 975 }
 976
 977 static void nfs_write_completion(struct nfs_pgio_header *hdr)
 978 {
 979         struct nfs_commit_info cinfo;
 980         unsigned long bytes = 0;
 981
 982         if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 983                 goto out;
 984         nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
 985         while (!list_empty(&hdr->pages)) {
 986                 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 987
 988                 bytes += req->wb_bytes;
 989                 nfs_list_remove_request(req);
 990                 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
 991                     (hdr->good_bytes < bytes)) {
 992                         trace_nfs_comp_error(req, hdr->error);
 993                         nfs_mapping_set_error(req->wb_page, hdr->error);
 994                         goto remove_req;
 995                 }
 996                 if (nfs_write_need_commit(hdr)) {
 997                         /* Reset wb_nio, since the write was successful. */
 998                         req->wb_nio = 0;
 999                         memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
1000                         nfs_mark_request_commit(req, hdr->lseg, &cinfo,
1001                                 hdr->pgio_mirror_idx);
1002                         goto next;
1003                 }
1004 remove_req:
1005                 nfs_inode_remove_request(req);
1006 next:
1007                 nfs_end_page_writeback(req);
1008                 nfs_release_request(req);
1009         }
1010 out:
1011         nfs_io_completion_put(hdr->io_completion);
1012         hdr->release(hdr);
1013 }
1014
1015 unsigned long
1016 nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
1017 {
1018         return atomic_long_read(&cinfo->mds->ncommit);
1019 }
1020
1021 /* NFS_I(cinfo->inode)->commit_mutex held by caller */
1022 int
1023 nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
1024                      struct nfs_commit_info *cinfo, int max)
1025 {
1026         struct nfs_page *req, *tmp;
1027         int ret = 0;
1028
1029         list_for_each_entry_safe(req, tmp, src, wb_list) {
1030                 kref_get(&req->wb_kref);
1031                 if (!nfs_lock_request(req)) {
1032                         nfs_release_request(req);
1033                         continue;
1034                 }
1035                 nfs_request_remove_commit_list(req, cinfo);
1036                 clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
1037                 nfs_list_add_request(req, dst);
1038                 ret++;
1039                 if ((ret == max) && !cinfo->dreq)
1040                         break;
1041                 cond_resched();
1042         }
1043         return ret;
1044 }
1045 EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
1046
1047 /*
1048  * nfs_scan_commit - Scan an inode for commit requests
1049  * @inode: NFS inode to scan
1050  * @dst: mds destination list
1051  * @cinfo: mds and ds lists of reqs ready to commit
1052  *
1053  * Moves requests from the inode's 'commit' request list.
1054  * The requests are *not* checked to ensure that they form a contiguous set.
1055  */
1056 int
1057 nfs_scan_commit(struct inode *inode, struct list_head *dst,
1058                 struct nfs_commit_info *cinfo)
1059 {
1060         int ret = 0;
1061
1062         if (!atomic_long_read(&cinfo->mds->ncommit))
1063                 return 0;
1064         mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
1065         if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
1066                 const int max = INT_MAX;
1067
1068                 ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
1069                                            cinfo, max);
1070                 ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
1071         }
1072         mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
1073         return ret;
1074 }
1075
1076 /*
1077  * Search for an existing write request, and attempt to update
1078  * it to reflect a new dirty region on a given page.
1079  *
1080  * If the attempt fails, then the existing request is flushed out
1081  * to disk.
1082  */
1083 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
1084                 struct page *page,
1085                 unsigned int offset,
1086                 unsigned int bytes)
1087 {
1088         struct nfs_page *req;
1089         unsigned int rqend;
1090         unsigned int end;
1091         int error;
1092
1093         end = offset + bytes;
1094
1095         req = nfs_lock_and_join_requests(page);
1096         if (IS_ERR_OR_NULL(req))
1097                 return req;
1098
1099         rqend = req->wb_offset + req->wb_bytes;
1100         /*
1101          * Tell the caller to flush out the request if
1102          * the offsets are non-contiguous.
1103          * Note: nfs_flush_incompatible() will already
1104          * have flushed out requests having wrong owners.
1105          */
1106         if (offset > rqend || end < req->wb_offset)
1107                 goto out_flushme;
1108
1109         /* Okay, the request matches. Update the region */
1110         if (offset < req->wb_offset) {
1111                 req->wb_offset = offset;
1112                 req->wb_pgbase = offset;
1113         }
1114         if (end > rqend)
1115                 req->wb_bytes = end - req->wb_offset;
1116         else
1117                 req->wb_bytes = rqend - req->wb_offset;
1118         req->wb_nio = 0;
1119         return req;
1120 out_flushme:
1121         /*
1122          * Note: we mark the request dirty here because
1123          * nfs_lock_and_join_requests() cannot preserve
1124          * commit flags, so we have to replay the write.
1125          */
1126         nfs_mark_request_dirty(req);
1127         nfs_unlock_and_release_request(req);
1128         error = nfs_wb_page(inode, page);
1129         return (error < 0) ? ERR_PTR(error) : NULL;
1130 }
1131
1132 /*
1133  * Try to update an existing write request, or create one if there is none.
1134  *
1135  * Note: Should always be called with the Page Lock held to prevent races
1136  * if we have to add a new request. Also assumes that the caller has
1137  * already called nfs_flush_incompatible() if necessary.
1138  */
1139 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
1140                 struct page *page, unsigned int offset, unsigned int bytes)
1141 {
1142         struct inode *inode = page_file_mapping(page)->host;
1143         struct nfs_page *req;
1144
1145         req = nfs_try_to_update_request(inode, page, offset, bytes);
1146         if (req != NULL)
1147                 goto out;
1148         req = nfs_create_request(ctx, page, offset, bytes);
1149         if (IS_ERR(req))
1150                 goto out;
1151         nfs_inode_add_request(inode, req);
1152 out:
1153         return req;
1154 }
1155
1156 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
1157                 unsigned int offset, unsigned int count)
1158 {
1159         struct nfs_page *req;
1160
1161         req = nfs_setup_write_request(ctx, page, offset, count);
1162         if (IS_ERR(req))
1163                 return PTR_ERR(req);
1164         /* Update file length */
1165         nfs_grow_file(page, offset, count);
1166         nfs_mark_uptodate(req);
1167         nfs_mark_request_dirty(req);
1168         nfs_unlock_and_release_request(req);
1169         return 0;
1170 }
1171
1172 int nfs_flush_incompatible(struct file *file, struct page *page)
1173 {
1174         struct nfs_open_context *ctx = nfs_file_open_context(file);
1175         struct nfs_lock_context *l_ctx;
1176         struct file_lock_context *flctx = file_inode(file)->i_flctx;
1177         struct nfs_page *req;
1178         int do_flush, status;
1179         /*
1180          * Look for a request corresponding to this page. If there
1181          * is one, and it belongs to another file, we flush it out
1182          * before we try to copy anything into the page. Do this
1183          * due to the lack of an ACCESS-type call in NFSv2.
1184          * Also do the same if we find a request from an existing
1185          * dropped page.
1186          */
1187         do {
1188                 req = nfs_page_find_head_request(page);
1189                 if (req == NULL)
1190                         return 0;
1191                 l_ctx = req->wb_lock_context;
1192                 do_flush = req->wb_page != page ||
1193                         !nfs_match_open_context(nfs_req_openctx(req), ctx);
1194                 if (l_ctx && flctx &&
1195                     !(list_empty_careful(&flctx->flc_posix) &&
1196                       list_empty_careful(&flctx->flc_flock))) {
1197                         do_flush |= l_ctx->lockowner != current->files;
1198                 }
1199                 nfs_release_request(req);
1200                 if (!do_flush)
1201                         return 0;
1202                 status = nfs_wb_page(page_file_mapping(page)->host, page);
1203         } while (status == 0);
1204         return status;
1205 }
1206
1207 /*
1208  * Avoid buffered writes when a open context credential's key would
1209  * expire soon.
1210  *
1211  * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
1212  *
1213  * Return 0 and set a credential flag which triggers the inode to flush
1214  * and performs  NFS_FILE_SYNC writes if the key will expired within
1215  * RPC_KEY_EXPIRE_TIMEO.
1216  */
1217 int
1218 nfs_key_timeout_notify(struct file *filp, struct inode *inode)
1219 {
1220         struct nfs_open_context *ctx = nfs_file_open_context(filp);
1221
1222         if (nfs_ctx_key_to_expire(ctx, inode) &&
1223             !ctx->ll_cred)
1224                 /* Already expired! */
1225                 return -EACCES;
1226         return 0;
1227 }
1228
1229 /*
1230  * Test if the open context credential key is marked to expire soon.
1231  */
1232 bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx, struct inode *inode)
1233 {
1234         struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
1235         struct rpc_cred *cred = ctx->ll_cred;
1236         struct auth_cred acred = {
1237                 .cred = ctx->cred,
1238         };
1239
1240         if (cred && !cred->cr_ops->crmatch(&acred, cred, 0)) {
1241                 put_rpccred(cred);
1242                 ctx->ll_cred = NULL;
1243                 cred = NULL;
1244         }
1245         if (!cred)
1246                 cred = auth->au_ops->lookup_cred(auth, &acred, 0);
1247         if (!cred || IS_ERR(cred))
1248                 return true;
1249         ctx->ll_cred = cred;
1250         return !!(cred->cr_ops->crkey_timeout &&
1251                   cred->cr_ops->crkey_timeout(cred));
1252 }
1253
1254 /*
1255  * If the page cache is marked as unsafe or invalid, then we can't rely on
1256  * the PageUptodate() flag. In this case, we will need to turn off
1257  * write optimisations that depend on the page contents being correct.
1258  */
1259 static bool nfs_write_pageuptodate(struct page *page, struct inode *inode)
1260 {
1261         struct nfs_inode *nfsi = NFS_I(inode);
1262
1263         if (nfs_have_delegated_attributes(inode))
1264                 goto out;
1265         if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
1266                 return false;
1267         smp_rmb();
1268         if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags))
1269                 return false;
1270 out:
1271         if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
1272                 return false;
1273         return PageUptodate(page) != 0;
1274 }
1275
1276 static bool
1277 is_whole_file_wrlock(struct file_lock *fl)
1278 {
1279         return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
1280                         fl->fl_type == F_WRLCK;
1281 }
1282
1283 /* If we know the page is up to date, and we're not using byte range locks (or
1284  * if we have the whole file locked for writing), it may be more efficient to
1285  * extend the write to cover the entire page in order to avoid fragmentation
1286  * inefficiencies.
1287  *
1288  * If the file is opened for synchronous writes then we can just skip the rest
1289  * of the checks.
1290  */
1291 static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode)
1292 {
1293         int ret;
1294         struct file_lock_context *flctx = inode->i_flctx;
1295         struct file_lock *fl;
1296
1297         if (file->f_flags & O_DSYNC)
1298                 return 0;
1299         if (!nfs_write_pageuptodate(page, inode))
1300                 return 0;
1301         if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
1302                 return 1;
1303         if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
1304                        list_empty_careful(&flctx->flc_posix)))
1305                 return 1;
1306
1307         /* Check to see if there are whole file write locks */
1308         ret = 0;
1309         spin_lock(&flctx->flc_lock);
1310         if (!list_empty(&flctx->flc_posix)) {
1311                 fl = list_first_entry(&flctx->flc_posix, struct file_lock,
1312                                         fl_list);
1313                 if (is_whole_file_wrlock(fl))
1314                         ret = 1;
1315         } else if (!list_empty(&flctx->flc_flock)) {
1316                 fl = list_first_entry(&flctx->flc_flock, struct file_lock,
1317                                         fl_list);
1318                 if (fl->fl_type == F_WRLCK)
1319                         ret = 1;
1320         }
1321         spin_unlock(&flctx->flc_lock);
1322         return ret;
1323 }
1324
1325 /*
1326  * Update and possibly write a cached page of an NFS file.
1327  *
1328  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
1329  * things with a page scheduled for an RPC call (e.g. invalidate it).
1330  */
1331 int nfs_updatepage(struct file *file, struct page *page,
1332                 unsigned int offset, unsigned int count)
1333 {
1334         struct nfs_open_context *ctx = nfs_file_open_context(file);
1335         struct address_space *mapping = page_file_mapping(page);
1336         struct inode    *inode = mapping->host;
1337         int             status = 0;
1338
1339         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
1340
1341         dprintk("NFS:       nfs_updatepage(%pD2 %d@%lld)\n",
1342                 file, count, (long long)(page_file_offset(page) + offset));
1343
1344         if (!count)
1345                 goto out;
1346
1347         if (nfs_can_extend_write(file, page, inode)) {
1348                 count = max(count + offset, nfs_page_length(page));
1349                 offset = 0;
1350         }
1351
1352         status = nfs_writepage_setup(ctx, page, offset, count);
1353         if (status < 0)
1354                 nfs_set_pageerror(mapping);
1355         else
1356                 __set_page_dirty_nobuffers(page);
1357 out:
1358         dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
1359                         status, (long long)i_size_read(inode));
1360         return status;
1361 }
1362
1363 static int flush_task_priority(int how)
1364 {
1365         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
1366                 case FLUSH_HIGHPRI:
1367                         return RPC_PRIORITY_HIGH;
1368                 case FLUSH_LOWPRI:
1369                         return RPC_PRIORITY_LOW;
1370         }
1371         return RPC_PRIORITY_NORMAL;
1372 }
1373
1374 static void nfs_initiate_write(struct nfs_pgio_header *hdr,
1375                                struct rpc_message *msg,
1376                                const struct nfs_rpc_ops *rpc_ops,
1377                                struct rpc_task_setup *task_setup_data, int how)
1378 {
1379         int priority = flush_task_priority(how);
1380
1381         task_setup_data->priority = priority;
1382         rpc_ops->write_setup(hdr, msg, &task_setup_data->rpc_client);
1383         trace_nfs_initiate_write(hdr);
1384 }
1385
1386 /* If a nfs_flush_* function fails, it should remove reqs from @head and
1387  * call this on each, which will prepare them to be retried on next
1388  * writeback using standard nfs.
1389  */
1390 static void nfs_redirty_request(struct nfs_page *req)
1391 {
1392         /* Bump the transmission count */
1393         req->wb_nio++;
1394         nfs_mark_request_dirty(req);
1395         set_bit(NFS_CONTEXT_RESEND_WRITES, &nfs_req_openctx(req)->flags);
1396         nfs_end_page_writeback(req);
1397         nfs_release_request(req);
1398 }
1399
1400 static void nfs_async_write_error(struct list_head *head, int error)
1401 {
1402         struct nfs_page *req;
1403
1404         while (!list_empty(head)) {
1405                 req = nfs_list_entry(head->next);
1406                 nfs_list_remove_request(req);
1407                 if (nfs_error_is_fatal_on_server(error))
1408                         nfs_write_error(req, error);
1409                 else
1410                         nfs_redirty_request(req);
1411         }
1412 }
1413
1414 static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
1415 {
1416         nfs_async_write_error(&hdr->pages, 0);
1417         filemap_fdatawrite_range(hdr->inode->i_mapping, hdr->args.offset,
1418                         hdr->args.offset + hdr->args.count - 1);
1419 }
1420
1421 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1422         .init_hdr = nfs_async_write_init,
1423         .error_cleanup = nfs_async_write_error,
1424         .completion = nfs_write_completion,
1425         .reschedule_io = nfs_async_write_reschedule_io,
1426 };
1427
1428 void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1429                                struct inode *inode, int ioflags, bool force_mds,
1430                                const struct nfs_pgio_completion_ops *compl_ops)
1431 {
1432         struct nfs_server *server = NFS_SERVER(inode);
1433         const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
1434
1435 #ifdef CONFIG_NFS_V4_1
1436         if (server->pnfs_curr_ld && !force_mds)
1437                 pg_ops = server->pnfs_curr_ld->pg_write_ops;
1438 #endif
1439         nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
1440                         server->wsize, ioflags);
1441 }
1442 EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1443
1444 void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1445 {
1446         struct nfs_pgio_mirror *mirror;
1447
1448         if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
1449                 pgio->pg_ops->pg_cleanup(pgio);
1450
1451         pgio->pg_ops = &nfs_pgio_rw_ops;
1452
1453         nfs_pageio_stop_mirroring(pgio);
1454
1455         mirror = &pgio->pg_mirrors[0];
1456         mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1457 }
1458 EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1459
1460
1461 void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1462 {
1463         struct nfs_commit_data *data = calldata;
1464
1465         NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1466 }
1467
1468 /*
1469  * Special version of should_remove_suid() that ignores capabilities.
1470  */
1471 static int nfs_should_remove_suid(const struct inode *inode)
1472 {
1473         umode_t mode = inode->i_mode;
1474         int kill = 0;
1475
1476         /* suid always must be killed */
1477         if (unlikely(mode & S_ISUID))
1478                 kill = ATTR_KILL_SUID;
1479
1480         /*
1481          * sgid without any exec bits is just a mandatory locking mark; leave
1482          * it alone.  If some exec bits are set, it's a real sgid; kill it.
1483          */
1484         if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
1485                 kill |= ATTR_KILL_SGID;
1486
1487         if (unlikely(kill && S_ISREG(mode)))
1488                 return kill;
1489
1490         return 0;
1491 }
1492
1493 static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
1494                 struct nfs_fattr *fattr)
1495 {
1496         struct nfs_pgio_args *argp = &hdr->args;
1497         struct nfs_pgio_res *resp = &hdr->res;
1498         u64 size = argp->offset + resp->count;
1499
1500         if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
1501                 fattr->size = size;
1502         if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
1503                 fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
1504                 return;
1505         }
1506         if (size != fattr->size)
1507                 return;
1508         /* Set attribute barrier */
1509         nfs_fattr_set_barrier(fattr);
1510         /* ...and update size */
1511         fattr->valid |= NFS_ATTR_FATTR_SIZE;
1512 }
1513
1514 void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
1515 {
1516         struct nfs_fattr *fattr = &hdr->fattr;
1517         struct inode *inode = hdr->inode;
1518
1519         spin_lock(&inode->i_lock);
1520         nfs_writeback_check_extend(hdr, fattr);
1521         nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
1522         spin_unlock(&inode->i_lock);
1523 }
1524 EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
1525
1526 /*
1527  * This function is called when the WRITE call is complete.
1528  */
1529 static int nfs_writeback_done(struct rpc_task *task,
1530                               struct nfs_pgio_header *hdr,
1531                               struct inode *inode)
1532 {
1533         int status;
1534
1535         /*
1536          * ->write_done will attempt to use post-op attributes to detect
1537          * conflicting writes by other clients.  A strict interpretation
1538          * of close-to-open would allow us to continue caching even if
1539          * another writer had changed the file, but some applications
1540          * depend on tighter cache coherency when writing.
1541          */
1542         status = NFS_PROTO(inode)->write_done(task, hdr);
1543         if (status != 0)
1544                 return status;
1545
1546         nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
1547         trace_nfs_writeback_done(task, hdr);
1548
1549         if (hdr->res.verf->committed < hdr->args.stable &&
1550             task->tk_status >= 0) {
1551                 /* We tried a write call, but the server did not
1552                  * commit data to stable storage even though we
1553                  * requested it.
1554                  * Note: There is a known bug in Tru64 < 5.0 in which
1555                  *       the server reports NFS_DATA_SYNC, but performs
1556                  *       NFS_FILE_SYNC. We therefore implement this checking
1557                  *       as a dprintk() in order to avoid filling syslog.
1558                  */
1559                 static unsigned long    complain;
1560
1561                 /* Note this will print the MDS for a DS write */
1562                 if (time_before(complain, jiffies)) {
1563                         dprintk("NFS:       faulty NFS server %s:"
1564                                 " (committed = %d) != (stable = %d)\n",
1565                                 NFS_SERVER(inode)->nfs_client->cl_hostname,
1566                                 hdr->res.verf->committed, hdr->args.stable);
1567                         complain = jiffies + 300 * HZ;
1568                 }
1569         }
1570
1571         /* Deal with the suid/sgid bit corner case */
1572         if (nfs_should_remove_suid(inode)) {
1573                 spin_lock(&inode->i_lock);
1574                 NFS_I(inode)->cache_validity |= NFS_INO_INVALID_OTHER;
1575                 spin_unlock(&inode->i_lock);
1576         }
1577         return 0;
1578 }
1579
1580 /*
1581  * This function is called when the WRITE call is complete.
1582  */
1583 static void nfs_writeback_result(struct rpc_task *task,
1584                                  struct nfs_pgio_header *hdr)
1585 {
1586         struct nfs_pgio_args    *argp = &hdr->args;
1587         struct nfs_pgio_res     *resp = &hdr->res;
1588
1589         if (resp->count < argp->count) {
1590                 static unsigned long    complain;
1591
1592                 /* This a short write! */
1593                 nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
1594
1595                 /* Has the server at least made some progress? */
1596                 if (resp->count == 0) {
1597                         if (time_before(complain, jiffies)) {
1598                                 printk(KERN_WARNING
1599                                        "NFS: Server wrote zero bytes, expected %u.\n",
1600                                        argp->count);
1601                                 complain = jiffies + 300 * HZ;
1602                         }
1603                         nfs_set_pgio_error(hdr, -EIO, argp->offset);
1604                         task->tk_status = -EIO;
1605                         return;
1606                 }
1607
1608                 /* For non rpc-based layout drivers, retry-through-MDS */
1609                 if (!task->tk_ops) {
1610                         hdr->pnfs_error = -EAGAIN;
1611                         return;
1612                 }
1613
1614                 /* Was this an NFSv2 write or an NFSv3 stable write? */
1615                 if (resp->verf->committed != NFS_UNSTABLE) {
1616                         /* Resend from where the server left off */
1617                         hdr->mds_offset += resp->count;
1618                         argp->offset += resp->count;
1619                         argp->pgbase += resp->count;
1620                         argp->count -= resp->count;
1621                 } else {
1622                         /* Resend as a stable write in order to avoid
1623                          * headaches in the case of a server crash.
1624                          */
1625                         argp->stable = NFS_FILE_SYNC;
1626                 }
1627                 resp->count = 0;
1628                 resp->verf->committed = 0;
1629                 rpc_restart_call_prepare(task);
1630         }
1631 }
1632
1633 static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
1634 {
1635         return wait_var_event_killable(&cinfo->rpcs_out,
1636                                        !atomic_read(&cinfo->rpcs_out));
1637 }
1638
1639 static void nfs_commit_begin(struct nfs_mds_commit_info *cinfo)
1640 {
1641         atomic_inc(&cinfo->rpcs_out);
1642 }
1643
1644 bool nfs_commit_end(struct nfs_mds_commit_info *cinfo)
1645 {
1646         if (atomic_dec_and_test(&cinfo->rpcs_out)) {
1647                 wake_up_var(&cinfo->rpcs_out);
1648                 return true;
1649         }
1650         return false;
1651 }
1652
1653 void nfs_commitdata_release(struct nfs_commit_data *data)
1654 {
1655         put_nfs_open_context(data->context);
1656         nfs_commit_free(data);
1657 }
1658 EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1659
1660 int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1661                         const struct nfs_rpc_ops *nfs_ops,
1662                         const struct rpc_call_ops *call_ops,
1663                         int how, int flags)
1664 {
1665         struct rpc_task *task;
1666         int priority = flush_task_priority(how);
1667         struct rpc_message msg = {
1668                 .rpc_argp = &data->args,
1669                 .rpc_resp = &data->res,
1670                 .rpc_cred = data->cred,
1671         };
1672         struct rpc_task_setup task_setup_data = {
1673                 .task = &data->task,
1674                 .rpc_client = clnt,
1675                 .rpc_message = &msg,
1676                 .callback_ops = call_ops,
1677                 .callback_data = data,
1678                 .workqueue = nfsiod_workqueue,
1679                 .flags = RPC_TASK_ASYNC | flags,
1680                 .priority = priority,
1681         };
1682         /* Set up the initial task struct.  */
1683         nfs_ops->commit_setup(data, &msg, &task_setup_data.rpc_client);
1684         trace_nfs_initiate_commit(data);
1685
1686         dprintk("NFS: initiated commit call\n");
1687
1688         task = rpc_run_task(&task_setup_data);
1689         if (IS_ERR(task))
1690                 return PTR_ERR(task);
1691         if (how & FLUSH_SYNC)
1692                 rpc_wait_for_completion_task(task);
1693         rpc_put_task(task);
1694         return 0;
1695 }
1696 EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1697
1698 static loff_t nfs_get_lwb(struct list_head *head)
1699 {
1700         loff_t lwb = 0;
1701         struct nfs_page *req;
1702
1703         list_for_each_entry(req, head, wb_list)
1704                 if (lwb < (req_offset(req) + req->wb_bytes))
1705                         lwb = req_offset(req) + req->wb_bytes;
1706
1707         return lwb;
1708 }
1709
1710 /*
1711  * Set up the argument/result storage required for the RPC call.
1712  */
1713 void nfs_init_commit(struct nfs_commit_data *data,
1714                      struct list_head *head,
1715                      struct pnfs_layout_segment *lseg,
1716                      struct nfs_commit_info *cinfo)
1717 {
1718         struct nfs_page *first;
1719         struct nfs_open_context *ctx;
1720         struct inode *inode;
1721
1722         /* Set up the RPC argument and reply structs
1723          * NB: take care not to mess about with data->commit et al. */
1724
1725         if (head)
1726                 list_splice_init(head, &data->pages);
1727
1728         first = nfs_list_entry(data->pages.next);
1729         ctx = nfs_req_openctx(first);
1730         inode = d_inode(ctx->dentry);
1731
1732         data->inode       = inode;
1733         data->cred        = ctx->cred;
1734         data->lseg        = lseg; /* reference transferred */
1735         /* only set lwb for pnfs commit */
1736         if (lseg)
1737                 data->lwb = nfs_get_lwb(&data->pages);
1738         data->mds_ops     = &nfs_commit_ops;
1739         data->completion_ops = cinfo->completion_ops;
1740         data->dreq        = cinfo->dreq;
1741
1742         data->args.fh     = NFS_FH(data->inode);
1743         /* Note: we always request a commit of the entire inode */
1744         data->args.offset = 0;
1745         data->args.count  = 0;
1746         data->context     = get_nfs_open_context(ctx);
1747         data->res.fattr   = &data->fattr;
1748         data->res.verf    = &data->verf;
1749         nfs_fattr_init(&data->fattr);
1750         nfs_commit_begin(cinfo->mds);
1751 }
1752 EXPORT_SYMBOL_GPL(nfs_init_commit);
1753
1754 void nfs_retry_commit(struct list_head *page_list,
1755                       struct pnfs_layout_segment *lseg,
1756                       struct nfs_commit_info *cinfo,
1757                       u32 ds_commit_idx)
1758 {
1759         struct nfs_page *req;
1760
1761         while (!list_empty(page_list)) {
1762                 req = nfs_list_entry(page_list->next);
1763                 nfs_list_remove_request(req);
1764                 nfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx);
1765                 if (!cinfo->dreq)
1766                         nfs_clear_page_commit(req->wb_page);
1767                 nfs_unlock_and_release_request(req);
1768         }
1769 }
1770 EXPORT_SYMBOL_GPL(nfs_retry_commit);
1771
1772 static void
1773 nfs_commit_resched_write(struct nfs_commit_info *cinfo,
1774                 struct nfs_page *req)
1775 {
1776         __set_page_dirty_nobuffers(req->wb_page);
1777 }
1778
1779 /*
1780  * Commit dirty pages
1781  */
1782 static int
1783 nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1784                 struct nfs_commit_info *cinfo)
1785 {
1786         struct nfs_commit_data  *data;
1787
1788         /* another commit raced with us */
1789         if (list_empty(head))
1790                 return 0;
1791
1792         data = nfs_commitdata_alloc();
1793         if (!data) {
1794                 nfs_retry_commit(head, NULL, cinfo, -1);
1795                 return -ENOMEM;
1796         }
1797
1798         /* Set up the argument struct */
1799         nfs_init_commit(data, head, NULL, cinfo);
1800         return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
1801                                    data->mds_ops, how, RPC_TASK_CRED_NOREF);
1802 }
1803
1804 /*
1805  * COMMIT call returned
1806  */
1807 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1808 {
1809         struct nfs_commit_data  *data = calldata;
1810
1811         dprintk("NFS: %5u nfs_commit_done (status %d)\n",
1812                                 task->tk_pid, task->tk_status);
1813
1814         /* Call the NFS version-specific code */
1815         NFS_PROTO(data->inode)->commit_done(task, data);
1816         trace_nfs_commit_done(task, data);
1817 }
1818
1819 static void nfs_commit_release_pages(struct nfs_commit_data *data)
1820 {
1821         const struct nfs_writeverf *verf = data->res.verf;
1822         struct nfs_page *req;
1823         int status = data->task.tk_status;
1824         struct nfs_commit_info cinfo;
1825         struct nfs_server *nfss;
1826
1827         while (!list_empty(&data->pages)) {
1828                 req = nfs_list_entry(data->pages.next);
1829                 nfs_list_remove_request(req);
1830                 if (req->wb_page)
1831                         nfs_clear_page_commit(req->wb_page);
1832
1833                 dprintk("NFS:       commit (%s/%llu %d@%lld)",
1834                         nfs_req_openctx(req)->dentry->d_sb->s_id,
1835                         (unsigned long long)NFS_FILEID(d_inode(nfs_req_openctx(req)->dentry)),
1836                         req->wb_bytes,
1837                         (long long)req_offset(req));
1838                 if (status < 0) {
1839                         if (req->wb_page) {
1840                                 trace_nfs_commit_error(req, status);
1841                                 nfs_mapping_set_error(req->wb_page, status);
1842                                 nfs_inode_remove_request(req);
1843                         }
1844                         dprintk_cont(", error = %d\n", status);
1845                         goto next;
1846                 }
1847
1848                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1849                  * returned by the server against all stored verfs. */
1850                 if (nfs_write_match_verf(verf, req)) {
1851                         /* We have a match */
1852                         if (req->wb_page)
1853                                 nfs_inode_remove_request(req);
1854                         dprintk_cont(" OK\n");
1855                         goto next;
1856                 }
1857                 /* We have a mismatch. Write the page again */
1858                 dprintk_cont(" mismatch\n");
1859                 nfs_mark_request_dirty(req);
1860                 set_bit(NFS_CONTEXT_RESEND_WRITES, &nfs_req_openctx(req)->flags);
1861         next:
1862                 nfs_unlock_and_release_request(req);
1863                 /* Latency breaker */
1864                 cond_resched();
1865         }
1866         nfss = NFS_SERVER(data->inode);
1867         if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
1868                 clear_bdi_congested(inode_to_bdi(data->inode), BLK_RW_ASYNC);
1869
1870         nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1871         nfs_commit_end(cinfo.mds);
1872 }
1873
1874 static void nfs_commit_release(void *calldata)
1875 {
1876         struct nfs_commit_data *data = calldata;
1877
1878         data->completion_ops->completion(data);
1879         nfs_commitdata_release(calldata);
1880 }
1881
1882 static const struct rpc_call_ops nfs_commit_ops = {
1883         .rpc_call_prepare = nfs_commit_prepare,
1884         .rpc_call_done = nfs_commit_done,
1885         .rpc_release = nfs_commit_release,
1886 };
1887
1888 static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1889         .completion = nfs_commit_release_pages,
1890         .resched_write = nfs_commit_resched_write,
1891 };
1892
1893 int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1894                             int how, struct nfs_commit_info *cinfo)
1895 {
1896         int status;
1897
1898         status = pnfs_commit_list(inode, head, how, cinfo);
1899         if (status == PNFS_NOT_ATTEMPTED)
1900                 status = nfs_commit_list(inode, head, how, cinfo);
1901         return status;
1902 }
1903
1904 static int __nfs_commit_inode(struct inode *inode, int how,
1905                 struct writeback_control *wbc)
1906 {
1907         LIST_HEAD(head);
1908         struct nfs_commit_info cinfo;
1909         int may_wait = how & FLUSH_SYNC;
1910         int ret, nscan;
1911
1912         how &= ~FLUSH_SYNC;
1913         nfs_init_cinfo_from_inode(&cinfo, inode);
1914         nfs_commit_begin(cinfo.mds);
1915         for (;;) {
1916                 ret = nscan = nfs_scan_commit(inode, &head, &cinfo);
1917                 if (ret <= 0)
1918                         break;
1919                 ret = nfs_generic_commit_list(inode, &head, how, &cinfo);
1920                 if (ret < 0)
1921                         break;
1922                 ret = 0;
1923                 if (wbc && wbc->sync_mode == WB_SYNC_NONE) {
1924                         if (nscan < wbc->nr_to_write)
1925                                 wbc->nr_to_write -= nscan;
1926                         else
1927                                 wbc->nr_to_write = 0;
1928                 }
1929                 if (nscan < INT_MAX)
1930                         break;
1931                 cond_resched();
1932         }
1933         nfs_commit_end(cinfo.mds);
1934         if (ret || !may_wait)
1935                 return ret;
1936         return wait_on_commit(cinfo.mds);
1937 }
1938
1939 int nfs_commit_inode(struct inode *inode, int how)
1940 {
1941         return __nfs_commit_inode(inode, how, NULL);
1942 }
1943 EXPORT_SYMBOL_GPL(nfs_commit_inode);
1944
1945 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1946 {
1947         struct nfs_inode *nfsi = NFS_I(inode);
1948         int flags = FLUSH_SYNC;
1949         int ret = 0;
1950
1951         if (wbc->sync_mode == WB_SYNC_NONE) {
1952                 /* no commits means nothing needs to be done */
1953                 if (!atomic_long_read(&nfsi->commit_info.ncommit))
1954                         goto check_requests_outstanding;
1955
1956                 /* Don't commit yet if this is a non-blocking flush and there
1957                  * are a lot of outstanding writes for this mapping.
1958                  */
1959                 if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
1960                         goto out_mark_dirty;
1961
1962                 /* don't wait for the COMMIT response */
1963                 flags = 0;
1964         }
1965
1966         ret = __nfs_commit_inode(inode, flags, wbc);
1967         if (!ret) {
1968                 if (flags & FLUSH_SYNC)
1969                         return 0;
1970         } else if (atomic_long_read(&nfsi->commit_info.ncommit))
1971                 goto out_mark_dirty;
1972
1973 check_requests_outstanding:
1974         if (!atomic_read(&nfsi->commit_info.rpcs_out))
1975                 return ret;
1976 out_mark_dirty:
1977         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1978         return ret;
1979 }
1980 EXPORT_SYMBOL_GPL(nfs_write_inode);
1981
1982 /*
1983  * Wrapper for filemap_write_and_wait_range()
1984  *
1985  * Needed for pNFS in order to ensure data becomes visible to the
1986  * client.
1987  */
1988 int nfs_filemap_write_and_wait_range(struct address_space *mapping,
1989                 loff_t lstart, loff_t lend)
1990 {
1991         int ret;
1992
1993         ret = filemap_write_and_wait_range(mapping, lstart, lend);
1994         if (ret == 0)
1995                 ret = pnfs_sync_inode(mapping->host, true);
1996         return ret;
1997 }
1998 EXPORT_SYMBOL_GPL(nfs_filemap_write_and_wait_range);
1999
2000 /*
2001  * flush the inode to disk.
2002  */
2003 int nfs_wb_all(struct inode *inode)
2004 {
2005         int ret;
2006
2007         trace_nfs_writeback_inode_enter(inode);
2008
2009         ret = filemap_write_and_wait(inode->i_mapping);
2010         if (ret)
2011                 goto out;
2012         ret = nfs_commit_inode(inode, FLUSH_SYNC);
2013         if (ret < 0)
2014                 goto out;
2015         pnfs_sync_inode(inode, true);
2016         ret = 0;
2017
2018 out:
2019         trace_nfs_writeback_inode_exit(inode, ret);
2020         return ret;
2021 }
2022 EXPORT_SYMBOL_GPL(nfs_wb_all);
2023
2024 int nfs_wb_page_cancel(struct inode *inode, struct page *page)
2025 {
2026         struct nfs_page *req;
2027         int ret = 0;
2028
2029         wait_on_page_writeback(page);
2030
2031         /* blocking call to cancel all requests and join to a single (head)
2032          * request */
2033         req = nfs_lock_and_join_requests(page);
2034
2035         if (IS_ERR(req)) {
2036                 ret = PTR_ERR(req);
2037         } else if (req) {
2038                 /* all requests from this page have been cancelled by
2039                  * nfs_lock_and_join_requests, so just remove the head
2040                  * request from the inode / page_private pointer and
2041                  * release it */
2042                 nfs_inode_remove_request(req);
2043                 nfs_unlock_and_release_request(req);
2044         }
2045
2046         return ret;
2047 }
2048
2049 /*
2050  * Write back all requests on one page - we do this before reading it.
2051  */
2052 int nfs_wb_page(struct inode *inode, struct page *page)
2053 {
2054         loff_t range_start = page_file_offset(page);
2055         loff_t range_end = range_start + (loff_t)(PAGE_SIZE - 1);
2056         struct writeback_control wbc = {
2057                 .sync_mode = WB_SYNC_ALL,
2058                 .nr_to_write = 0,
2059                 .range_start = range_start,
2060                 .range_end = range_end,
2061         };
2062         int ret;
2063
2064         trace_nfs_writeback_page_enter(inode);
2065
2066         for (;;) {
2067                 wait_on_page_writeback(page);
2068                 if (clear_page_dirty_for_io(page)) {
2069                         ret = nfs_writepage_locked(page, &wbc);
2070                         if (ret < 0)
2071                                 goto out_error;
2072                         continue;
2073                 }
2074                 ret = 0;
2075                 if (!PagePrivate(page))
2076                         break;
2077                 ret = nfs_commit_inode(inode, FLUSH_SYNC);
2078                 if (ret < 0)
2079                         goto out_error;
2080         }
2081 out_error:
2082         trace_nfs_writeback_page_exit(inode, ret);
2083         return ret;
2084 }
2085
2086 #ifdef CONFIG_MIGRATION
2087 int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
2088                 struct page *page, enum migrate_mode mode)
2089 {
2090         /*
2091          * If PagePrivate is set, then the page is currently associated with
2092          * an in-progress read or write request. Don't try to migrate it.
2093          *
2094          * FIXME: we could do this in principle, but we'll need a way to ensure
2095          *        that we can safely release the inode reference while holding
2096          *        the page lock.
2097          */
2098         if (PagePrivate(page))
2099                 return -EBUSY;
2100
2101         if (!nfs_fscache_release_page(page, GFP_KERNEL))
2102                 return -EBUSY;
2103
2104         return migrate_page(mapping, newpage, page, mode);
2105 }
2106 #endif
2107
2108 int __init nfs_init_writepagecache(void)
2109 {
2110         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
2111                                              sizeof(struct nfs_pgio_header),
2112                                              0, SLAB_HWCACHE_ALIGN,
2113                                              NULL);
2114         if (nfs_wdata_cachep == NULL)
2115                 return -ENOMEM;
2116
2117         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
2118                                                      nfs_wdata_cachep);
2119         if (nfs_wdata_mempool == NULL)
2120                 goto out_destroy_write_cache;
2121
2122         nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
2123                                              sizeof(struct nfs_commit_data),
2124                                              0, SLAB_HWCACHE_ALIGN,
2125                                              NULL);
2126         if (nfs_cdata_cachep == NULL)
2127                 goto out_destroy_write_mempool;
2128
2129         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
2130                                                       nfs_cdata_cachep);
2131         if (nfs_commit_mempool == NULL)
2132                 goto out_destroy_commit_cache;
2133
2134         /*
2135          * NFS congestion size, scale with available memory.
2136          *
2137          *  64MB:    8192k
2138          * 128MB:   11585k
2139          * 256MB:   16384k
2140          * 512MB:   23170k
2141          *   1GB:   32768k
2142          *   2GB:   46340k
2143          *   4GB:   65536k
2144          *   8GB:   92681k
2145          *  16GB:  131072k
2146          *
2147          * This allows larger machines to have larger/more transfers.
2148          * Limit the default to 256M
2149          */
2150         nfs_congestion_kb = (16*int_sqrt(totalram_pages())) << (PAGE_SHIFT-10);
2151         if (nfs_congestion_kb > 256*1024)
2152                 nfs_congestion_kb = 256*1024;
2153
2154         return 0;
2155
2156 out_destroy_commit_cache:
2157         kmem_cache_destroy(nfs_cdata_cachep);
2158 out_destroy_write_mempool:
2159         mempool_destroy(nfs_wdata_mempool);
2160 out_destroy_write_cache:
2161         kmem_cache_destroy(nfs_wdata_cachep);
2162         return -ENOMEM;
2163 }
2164
2165 void nfs_destroy_writepagecache(void)
2166 {
2167         mempool_destroy(nfs_commit_mempool);
2168         kmem_cache_destroy(nfs_cdata_cachep);
2169         mempool_destroy(nfs_wdata_mempool);
2170         kmem_cache_destroy(nfs_wdata_cachep);
2171 }
2172
2173 static const struct nfs_rw_ops nfs_rw_write_ops = {
2174         .rw_alloc_header        = nfs_writehdr_alloc,
2175         .rw_free_header         = nfs_writehdr_free,
2176         .rw_done                = nfs_writeback_done,
2177         .rw_result              = nfs_writeback_result,
2178         .rw_initiate            = nfs_initiate_write,
2179 };