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         trace_nfs_size_grow(inode, end);
 288         i_size_write(inode, end);
 289         NFS_I(inode)->cache_validity &= ~NFS_INO_INVALID_SIZE;
 290         nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
 291 out:
 292         spin_unlock(&inode->i_lock);
 293         nfs_fscache_invalidate(inode, 0);
 294 }
 295
 296 /* A writeback failed: mark the page as bad, and invalidate the page cache */
 297 static void nfs_set_pageerror(struct address_space *mapping)
 298 {
 299         struct inode *inode = mapping->host;
 300
 301         nfs_zap_mapping(mapping->host, mapping);
 302         /* Force file size revalidation */
 303         spin_lock(&inode->i_lock);
 304         nfs_set_cache_invalid(inode, NFS_INO_REVAL_FORCED |
 305                                              NFS_INO_INVALID_CHANGE |
 306                                              NFS_INO_INVALID_SIZE);
 307         spin_unlock(&inode->i_lock);
 308 }
 309
 310 static void nfs_mapping_set_error(struct page *page, int error)
 311 {
 312         struct address_space *mapping = page_file_mapping(page);
 313
 314         SetPageError(page);
 315         filemap_set_wb_err(mapping, error);
 316         if (mapping->host)
 317                 errseq_set(&mapping->host->i_sb->s_wb_err,
 318                            error == -ENOSPC ? -ENOSPC : -EIO);
 319         nfs_set_pageerror(mapping);
 320 }
 321
 322 /*
 323  * nfs_page_group_search_locked
 324  * @head - head request of page group
 325  * @page_offset - offset into page
 326  *
 327  * Search page group with head @head to find a request that contains the
 328  * page offset @page_offset.
 329  *
 330  * Returns a pointer to the first matching nfs request, or NULL if no
 331  * match is found.
 332  *
 333  * Must be called with the page group lock held
 334  */
 335 static struct nfs_page *
 336 nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)
 337 {
 338         struct nfs_page *req;
 339
 340         req = head;
 341         do {
 342                 if (page_offset >= req->wb_pgbase &&
 343                     page_offset < (req->wb_pgbase + req->wb_bytes))
 344                         return req;
 345
 346                 req = req->wb_this_page;
 347         } while (req != head);
 348
 349         return NULL;
 350 }
 351
 352 /*
 353  * nfs_page_group_covers_page
 354  * @head - head request of page group
 355  *
 356  * Return true if the page group with head @head covers the whole page,
 357  * returns false otherwise
 358  */
 359 static bool nfs_page_group_covers_page(struct nfs_page *req)
 360 {
 361         struct nfs_page *tmp;
 362         unsigned int pos = 0;
 363         unsigned int len = nfs_page_length(req->wb_page);
 364
 365         nfs_page_group_lock(req);
 366
 367         for (;;) {
 368                 tmp = nfs_page_group_search_locked(req->wb_head, pos);
 369                 if (!tmp)
 370                         break;
 371                 pos = tmp->wb_pgbase + tmp->wb_bytes;
 372         }
 373
 374         nfs_page_group_unlock(req);
 375         return pos >= len;
 376 }
 377
 378 /* We can set the PG_uptodate flag if we see that a write request
 379  * covers the full page.
 380  */
 381 static void nfs_mark_uptodate(struct nfs_page *req)
 382 {
 383         if (PageUptodate(req->wb_page))
 384                 return;
 385         if (!nfs_page_group_covers_page(req))
 386                 return;
 387         SetPageUptodate(req->wb_page);
 388 }
 389
 390 static int wb_priority(struct writeback_control *wbc)
 391 {
 392         int ret = 0;
 393
 394         if (wbc->sync_mode == WB_SYNC_ALL)
 395                 ret = FLUSH_COND_STABLE;
 396         return ret;
 397 }
 398
 399 /*
 400  * NFS congestion control
 401  */
 402
 403 int nfs_congestion_kb;
 404
 405 #define NFS_CONGESTION_ON_THRESH        (nfs_congestion_kb >> (PAGE_SHIFT-10))
 406 #define NFS_CONGESTION_OFF_THRESH       \
 407         (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 408
 409 static void nfs_set_page_writeback(struct page *page)
 410 {
 411         struct inode *inode = page_file_mapping(page)->host;
 412         struct nfs_server *nfss = NFS_SERVER(inode);
 413         int ret = test_set_page_writeback(page);
 414
 415         WARN_ON_ONCE(ret != 0);
 416
 417         if (atomic_long_inc_return(&nfss->writeback) >
 418                         NFS_CONGESTION_ON_THRESH)
 419                 nfss->write_congested = 1;
 420 }
 421
 422 static void nfs_end_page_writeback(struct nfs_page *req)
 423 {
 424         struct inode *inode = page_file_mapping(req->wb_page)->host;
 425         struct nfs_server *nfss = NFS_SERVER(inode);
 426         bool is_done;
 427
 428         is_done = nfs_page_group_sync_on_bit(req, PG_WB_END);
 429         nfs_unlock_request(req);
 430         if (!is_done)
 431                 return;
 432
 433         end_page_writeback(req->wb_page);
 434         if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
 435                 nfss->write_congested = 0;
 436 }
 437
 438 /*
 439  * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests
 440  *
 441  * @destroy_list - request list (using wb_this_page) terminated by @old_head
 442  * @old_head - the old head of the list
 443  *
 444  * All subrequests must be locked and removed from all lists, so at this point
 445  * they are only "active" in this function, and possibly in nfs_wait_on_request
 446  * with a reference held by some other context.
 447  */
 448 static void
 449 nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
 450                                  struct nfs_page *old_head,
 451                                  struct inode *inode)
 452 {
 453         while (destroy_list) {
 454                 struct nfs_page *subreq = destroy_list;
 455
 456                 destroy_list = (subreq->wb_this_page == old_head) ?
 457                                    NULL : subreq->wb_this_page;
 458
 459                 /* Note: lock subreq in order to change subreq->wb_head */
 460                 nfs_page_set_headlock(subreq);
 461                 WARN_ON_ONCE(old_head != subreq->wb_head);
 462
 463                 /* make sure old group is not used */
 464                 subreq->wb_this_page = subreq;
 465                 subreq->wb_head = subreq;
 466
 467                 clear_bit(PG_REMOVE, &subreq->wb_flags);
 468
 469                 /* Note: races with nfs_page_group_destroy() */
 470                 if (!kref_read(&subreq->wb_kref)) {
 471                         /* Check if we raced with nfs_page_group_destroy() */
 472                         if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags)) {
 473                                 nfs_page_clear_headlock(subreq);
 474                                 nfs_free_request(subreq);
 475                         } else
 476                                 nfs_page_clear_headlock(subreq);
 477                         continue;
 478                 }
 479                 nfs_page_clear_headlock(subreq);
 480
 481                 nfs_release_request(old_head);
 482
 483                 if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
 484                         nfs_release_request(subreq);
 485                         atomic_long_dec(&NFS_I(inode)->nrequests);
 486                 }
 487
 488                 /* subreq is now totally disconnected from page group or any
 489                  * write / commit lists. last chance to wake any waiters */
 490                 nfs_unlock_and_release_request(subreq);
 491         }
 492 }
 493
 494 /*
 495  * nfs_join_page_group - destroy subrequests of the head req
 496  * @head: the page used to lookup the "page group" of nfs_page structures
 497  * @inode: Inode to which the request belongs.
 498  *
 499  * This function joins all sub requests to the head request by first
 500  * locking all requests in the group, cancelling any pending operations
 501  * and finally updating the head request to cover the whole range covered by
 502  * the (former) group.  All subrequests are removed from any write or commit
 503  * lists, unlinked from the group and destroyed.
 504  */
 505 void
 506 nfs_join_page_group(struct nfs_page *head, struct inode *inode)
 507 {
 508         struct nfs_page *subreq;
 509         struct nfs_page *destroy_list = NULL;
 510         unsigned int pgbase, off, bytes;
 511
 512         pgbase = head->wb_pgbase;
 513         bytes = head->wb_bytes;
 514         off = head->wb_offset;
 515         for (subreq = head->wb_this_page; subreq != head;
 516                         subreq = subreq->wb_this_page) {
 517                 /* Subrequests should always form a contiguous range */
 518                 if (pgbase > subreq->wb_pgbase) {
 519                         off -= pgbase - subreq->wb_pgbase;
 520                         bytes += pgbase - subreq->wb_pgbase;
 521                         pgbase = subreq->wb_pgbase;
 522                 }
 523                 bytes = max(subreq->wb_pgbase + subreq->wb_bytes
 524                                 - pgbase, bytes);
 525         }
 526
 527         /* Set the head request's range to cover the former page group */
 528         head->wb_pgbase = pgbase;
 529         head->wb_bytes = bytes;
 530         head->wb_offset = off;
 531
 532         /* Now that all requests are locked, make sure they aren't on any list.
 533          * Commit list removal accounting is done after locks are dropped */
 534         subreq = head;
 535         do {
 536                 nfs_clear_request_commit(subreq);
 537                 subreq = subreq->wb_this_page;
 538         } while (subreq != head);
 539
 540         /* unlink subrequests from head, destroy them later */
 541         if (head->wb_this_page != head) {
 542                 /* destroy list will be terminated by head */
 543                 destroy_list = head->wb_this_page;
 544                 head->wb_this_page = head;
 545         }
 546
 547         nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
 548 }
 549
 550 /*
 551  * nfs_lock_and_join_requests - join all subreqs to the head req
 552  * @page: the page used to lookup the "page group" of nfs_page structures
 553  *
 554  * This function joins all sub requests to the head request by first
 555  * locking all requests in the group, cancelling any pending operations
 556  * and finally updating the head request to cover the whole range covered by
 557  * the (former) group.  All subrequests are removed from any write or commit
 558  * lists, unlinked from the group and destroyed.
 559  *
 560  * Returns a locked, referenced pointer to the head request - which after
 561  * this call is guaranteed to be the only request associated with the page.
 562  * Returns NULL if no requests are found for @page, or a ERR_PTR if an
 563  * error was encountered.
 564  */
 565 static struct nfs_page *
 566 nfs_lock_and_join_requests(struct page *page)
 567 {
 568         struct inode *inode = page_file_mapping(page)->host;
 569         struct nfs_page *head;
 570         int ret;
 571
 572         /*
 573          * A reference is taken only on the head request which acts as a
 574          * reference to the whole page group - the group will not be destroyed
 575          * until the head reference is released.
 576          */
 577         head = nfs_find_and_lock_page_request(page);
 578         if (IS_ERR_OR_NULL(head))
 579                 return head;
 580
 581         /* lock each request in the page group */
 582         ret = nfs_page_group_lock_subrequests(head);
 583         if (ret < 0) {
 584                 nfs_unlock_and_release_request(head);
 585                 return ERR_PTR(ret);
 586         }
 587
 588         nfs_join_page_group(head, inode);
 589
 590         return head;
 591 }
 592
 593 static void nfs_write_error(struct nfs_page *req, int error)
 594 {
 595         trace_nfs_write_error(req, error);
 596         nfs_mapping_set_error(req->wb_page, error);
 597         nfs_inode_remove_request(req);
 598         nfs_end_page_writeback(req);
 599         nfs_release_request(req);
 600 }
 601
 602 /*
 603  * Find an associated nfs write request, and prepare to flush it out
 604  * May return an error if the user signalled nfs_wait_on_request().
 605  */
 606 static int nfs_page_async_flush(struct page *page,
 607                                 struct writeback_control *wbc,
 608                                 struct nfs_pageio_descriptor *pgio)
 609 {
 610         struct nfs_page *req;
 611         int ret = 0;
 612
 613         req = nfs_lock_and_join_requests(page);
 614         if (!req)
 615                 goto out;
 616         ret = PTR_ERR(req);
 617         if (IS_ERR(req))
 618                 goto out;
 619
 620         nfs_set_page_writeback(page);
 621         WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
 622
 623         /* If there is a fatal error that covers this write, just exit */
 624         ret = pgio->pg_error;
 625         if (nfs_error_is_fatal_on_server(ret))
 626                 goto out_launder;
 627
 628         ret = 0;
 629         if (!nfs_pageio_add_request(pgio, req)) {
 630                 ret = pgio->pg_error;
 631                 /*
 632                  * Remove the problematic req upon fatal errors on the server
 633                  */
 634                 if (nfs_error_is_fatal_on_server(ret))
 635                         goto out_launder;
 636                 if (wbc->sync_mode == WB_SYNC_NONE)
 637                         ret = AOP_WRITEPAGE_ACTIVATE;
 638                 redirty_page_for_writepage(wbc, page);
 639                 nfs_redirty_request(req);
 640                 pgio->pg_error = 0;
 641         } else
 642                 nfs_add_stats(page_file_mapping(page)->host,
 643                                 NFSIOS_WRITEPAGES, 1);
 644 out:
 645         return ret;
 646 out_launder:
 647         nfs_write_error(req, ret);
 648         return 0;
 649 }
 650
 651 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc,
 652                             struct nfs_pageio_descriptor *pgio)
 653 {
 654         nfs_pageio_cond_complete(pgio, page_index(page));
 655         return nfs_page_async_flush(page, wbc, pgio);
 656 }
 657
 658 /*
 659  * Write an mmapped page to the server.
 660  */
 661 static int nfs_writepage_locked(struct page *page,
 662                                 struct writeback_control *wbc)
 663 {
 664         struct nfs_pageio_descriptor pgio;
 665         struct inode *inode = page_file_mapping(page)->host;
 666         int err;
 667
 668         if (wbc->sync_mode == WB_SYNC_NONE &&
 669             NFS_SERVER(inode)->write_congested)
 670                 return AOP_WRITEPAGE_ACTIVATE;
 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 = NULL;
 711         unsigned int mntflags = NFS_SERVER(inode)->flags;
 712         int priority = 0;
 713         int err;
 714
 715         if (wbc->sync_mode == WB_SYNC_NONE &&
 716             NFS_SERVER(inode)->write_congested)
 717                 return 0;
 718
 719         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 720
 721         if (!(mntflags & NFS_MOUNT_WRITE_EAGER) || wbc->for_kupdate ||
 722             wbc->for_background || wbc->for_sync || wbc->for_reclaim) {
 723                 ioc = nfs_io_completion_alloc(GFP_KERNEL);
 724                 if (ioc)
 725                         nfs_io_completion_init(ioc, nfs_io_completion_commit,
 726                                                inode);
 727                 priority = wb_priority(wbc);
 728         }
 729
 730         do {
 731                 nfs_pageio_init_write(&pgio, inode, priority, false,
 732                                       &nfs_async_write_completion_ops);
 733                 pgio.pg_io_completion = ioc;
 734                 err = write_cache_pages(mapping, wbc, nfs_writepages_callback,
 735                                         &pgio);
 736                 pgio.pg_error = 0;
 737                 nfs_pageio_complete(&pgio);
 738         } while (err < 0 && !nfs_error_is_fatal(err));
 739         nfs_io_completion_put(ioc);
 740
 741         if (err < 0)
 742                 goto out_err;
 743         return 0;
 744 out_err:
 745         return err;
 746 }
 747
 748 /*
 749  * Insert a write request into an inode
 750  */
 751 static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
 752 {
 753         struct address_space *mapping = page_file_mapping(req->wb_page);
 754         struct nfs_inode *nfsi = NFS_I(inode);
 755
 756         WARN_ON_ONCE(req->wb_this_page != req);
 757
 758         /* Lock the request! */
 759         nfs_lock_request(req);
 760
 761         /*
 762          * Swap-space should not get truncated. Hence no need to plug the race
 763          * with invalidate/truncate.
 764          */
 765         spin_lock(&mapping->private_lock);
 766         if (likely(!PageSwapCache(req->wb_page))) {
 767                 set_bit(PG_MAPPED, &req->wb_flags);
 768                 SetPagePrivate(req->wb_page);
 769                 set_page_private(req->wb_page, (unsigned long)req);
 770         }
 771         spin_unlock(&mapping->private_lock);
 772         atomic_long_inc(&nfsi->nrequests);
 773         /* this a head request for a page group - mark it as having an
 774          * extra reference so sub groups can follow suit.
 775          * This flag also informs pgio layer when to bump nrequests when
 776          * adding subrequests. */
 777         WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
 778         kref_get(&req->wb_kref);
 779 }
 780
 781 /*
 782  * Remove a write request from an inode
 783  */
 784 static void nfs_inode_remove_request(struct nfs_page *req)
 785 {
 786         struct address_space *mapping = page_file_mapping(req->wb_page);
 787         struct inode *inode = mapping->host;
 788         struct nfs_inode *nfsi = NFS_I(inode);
 789         struct nfs_page *head;
 790
 791         if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
 792                 head = req->wb_head;
 793
 794                 spin_lock(&mapping->private_lock);
 795                 if (likely(head->wb_page && !PageSwapCache(head->wb_page))) {
 796                         set_page_private(head->wb_page, 0);
 797                         ClearPagePrivate(head->wb_page);
 798                         clear_bit(PG_MAPPED, &head->wb_flags);
 799                 }
 800                 spin_unlock(&mapping->private_lock);
 801         }
 802
 803         if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) {
 804                 nfs_release_request(req);
 805                 atomic_long_dec(&nfsi->nrequests);
 806         }
 807 }
 808
 809 static void
 810 nfs_mark_request_dirty(struct nfs_page *req)
 811 {
 812         if (req->wb_page)
 813                 __set_page_dirty_nobuffers(req->wb_page);
 814 }
 815
 816 /*
 817  * nfs_page_search_commits_for_head_request_locked
 818  *
 819  * Search through commit lists on @inode for the head request for @page.
 820  * Must be called while holding the inode (which is cinfo) lock.
 821  *
 822  * Returns the head request if found, or NULL if not found.
 823  */
 824 static struct nfs_page *
 825 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
 826                                                 struct page *page)
 827 {
 828         struct nfs_page *freq, *t;
 829         struct nfs_commit_info cinfo;
 830         struct inode *inode = &nfsi->vfs_inode;
 831
 832         nfs_init_cinfo_from_inode(&cinfo, inode);
 833
 834         /* search through pnfs commit lists */
 835         freq = pnfs_search_commit_reqs(inode, &cinfo, page);
 836         if (freq)
 837                 return freq->wb_head;
 838
 839         /* Linearly search the commit list for the correct request */
 840         list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
 841                 if (freq->wb_page == page)
 842                         return freq->wb_head;
 843         }
 844
 845         return NULL;
 846 }
 847
 848 /**
 849  * nfs_request_add_commit_list_locked - add request to a commit list
 850  * @req: pointer to a struct nfs_page
 851  * @dst: commit list head
 852  * @cinfo: holds list lock and accounting info
 853  *
 854  * This sets the PG_CLEAN bit, updates the cinfo count of
 855  * number of outstanding requests requiring a commit as well as
 856  * the MM page stats.
 857  *
 858  * The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
 859  * nfs_page lock.
 860  */
 861 void
 862 nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
 863                             struct nfs_commit_info *cinfo)
 864 {
 865         set_bit(PG_CLEAN, &req->wb_flags);
 866         nfs_list_add_request(req, dst);
 867         atomic_long_inc(&cinfo->mds->ncommit);
 868 }
 869 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
 870
 871 /**
 872  * nfs_request_add_commit_list - add request to a commit list
 873  * @req: pointer to a struct nfs_page
 874  * @cinfo: holds list lock and accounting info
 875  *
 876  * This sets the PG_CLEAN bit, updates the cinfo count of
 877  * number of outstanding requests requiring a commit as well as
 878  * the MM page stats.
 879  *
 880  * The caller must _not_ hold the cinfo->lock, but must be
 881  * holding the nfs_page lock.
 882  */
 883 void
 884 nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
 885 {
 886         mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
 887         nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
 888         mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
 889         if (req->wb_page)
 890                 nfs_mark_page_unstable(req->wb_page, cinfo);
 891 }
 892 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list);
 893
 894 /**
 895  * nfs_request_remove_commit_list - Remove request from a commit list
 896  * @req: pointer to a nfs_page
 897  * @cinfo: holds list lock and accounting info
 898  *
 899  * This clears the PG_CLEAN bit, and updates the cinfo's count of
 900  * number of outstanding requests requiring a commit
 901  * It does not update the MM page stats.
 902  *
 903  * The caller _must_ hold the cinfo->lock and the nfs_page lock.
 904  */
 905 void
 906 nfs_request_remove_commit_list(struct nfs_page *req,
 907                                struct nfs_commit_info *cinfo)
 908 {
 909         if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags))
 910                 return;
 911         nfs_list_remove_request(req);
 912         atomic_long_dec(&cinfo->mds->ncommit);
 913 }
 914 EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list);
 915
 916 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
 917                                       struct inode *inode)
 918 {
 919         cinfo->inode = inode;
 920         cinfo->mds = &NFS_I(inode)->commit_info;
 921         cinfo->ds = pnfs_get_ds_info(inode);
 922         cinfo->dreq = NULL;
 923         cinfo->completion_ops = &nfs_commit_completion_ops;
 924 }
 925
 926 void nfs_init_cinfo(struct nfs_commit_info *cinfo,
 927                     struct inode *inode,
 928                     struct nfs_direct_req *dreq)
 929 {
 930         if (dreq)
 931                 nfs_init_cinfo_from_dreq(cinfo, dreq);
 932         else
 933                 nfs_init_cinfo_from_inode(cinfo, inode);
 934 }
 935 EXPORT_SYMBOL_GPL(nfs_init_cinfo);
 936
 937 /*
 938  * Add a request to the inode's commit list.
 939  */
 940 void
 941 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg,
 942                         struct nfs_commit_info *cinfo, u32 ds_commit_idx)
 943 {
 944         if (pnfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx))
 945                 return;
 946         nfs_request_add_commit_list(req, cinfo);
 947 }
 948
 949 static void
 950 nfs_clear_page_commit(struct page *page)
 951 {
 952         dec_node_page_state(page, NR_WRITEBACK);
 953         dec_wb_stat(&inode_to_bdi(page_file_mapping(page)->host)->wb,
 954                     WB_WRITEBACK);
 955 }
 956
 957 /* Called holding the request lock on @req */
 958 static void
 959 nfs_clear_request_commit(struct nfs_page *req)
 960 {
 961         if (test_bit(PG_CLEAN, &req->wb_flags)) {
 962                 struct nfs_open_context *ctx = nfs_req_openctx(req);
 963                 struct inode *inode = d_inode(ctx->dentry);
 964                 struct nfs_commit_info cinfo;
 965
 966                 nfs_init_cinfo_from_inode(&cinfo, inode);
 967                 mutex_lock(&NFS_I(inode)->commit_mutex);
 968                 if (!pnfs_clear_request_commit(req, &cinfo)) {
 969                         nfs_request_remove_commit_list(req, &cinfo);
 970                 }
 971                 mutex_unlock(&NFS_I(inode)->commit_mutex);
 972                 nfs_clear_page_commit(req->wb_page);
 973         }
 974 }
 975
 976 int nfs_write_need_commit(struct nfs_pgio_header *hdr)
 977 {
 978         if (hdr->verf.committed == NFS_DATA_SYNC)
 979                 return hdr->lseg == NULL;
 980         return hdr->verf.committed != NFS_FILE_SYNC;
 981 }
 982
 983 static void nfs_async_write_init(struct nfs_pgio_header *hdr)
 984 {
 985         nfs_io_completion_get(hdr->io_completion);
 986 }
 987
 988 static void nfs_write_completion(struct nfs_pgio_header *hdr)
 989 {
 990         struct nfs_commit_info cinfo;
 991         unsigned long bytes = 0;
 992
 993         if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 994                 goto out;
 995         nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
 996         while (!list_empty(&hdr->pages)) {
 997                 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 998
 999                 bytes += req->wb_bytes;
1000                 nfs_list_remove_request(req);
1001                 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
1002                     (hdr->good_bytes < bytes)) {
1003                         trace_nfs_comp_error(req, hdr->error);
1004                         nfs_mapping_set_error(req->wb_page, hdr->error);
1005                         goto remove_req;
1006                 }
1007                 if (nfs_write_need_commit(hdr)) {
1008                         /* Reset wb_nio, since the write was successful. */
1009                         req->wb_nio = 0;
1010                         memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
1011                         nfs_mark_request_commit(req, hdr->lseg, &cinfo,
1012                                 hdr->pgio_mirror_idx);
1013                         goto next;
1014                 }
1015 remove_req:
1016                 nfs_inode_remove_request(req);
1017 next:
1018                 nfs_end_page_writeback(req);
1019                 nfs_release_request(req);
1020         }
1021 out:
1022         nfs_io_completion_put(hdr->io_completion);
1023         hdr->release(hdr);
1024 }
1025
1026 unsigned long
1027 nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
1028 {
1029         return atomic_long_read(&cinfo->mds->ncommit);
1030 }
1031
1032 /* NFS_I(cinfo->inode)->commit_mutex held by caller */
1033 int
1034 nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
1035                      struct nfs_commit_info *cinfo, int max)
1036 {
1037         struct nfs_page *req, *tmp;
1038         int ret = 0;
1039
1040         list_for_each_entry_safe(req, tmp, src, wb_list) {
1041                 kref_get(&req->wb_kref);
1042                 if (!nfs_lock_request(req)) {
1043                         nfs_release_request(req);
1044                         continue;
1045                 }
1046                 nfs_request_remove_commit_list(req, cinfo);
1047                 clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
1048                 nfs_list_add_request(req, dst);
1049                 ret++;
1050                 if ((ret == max) && !cinfo->dreq)
1051                         break;
1052                 cond_resched();
1053         }
1054         return ret;
1055 }
1056 EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
1057
1058 /*
1059  * nfs_scan_commit - Scan an inode for commit requests
1060  * @inode: NFS inode to scan
1061  * @dst: mds destination list
1062  * @cinfo: mds and ds lists of reqs ready to commit
1063  *
1064  * Moves requests from the inode's 'commit' request list.
1065  * The requests are *not* checked to ensure that they form a contiguous set.
1066  */
1067 int
1068 nfs_scan_commit(struct inode *inode, struct list_head *dst,
1069                 struct nfs_commit_info *cinfo)
1070 {
1071         int ret = 0;
1072
1073         if (!atomic_long_read(&cinfo->mds->ncommit))
1074                 return 0;
1075         mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
1076         if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
1077                 const int max = INT_MAX;
1078
1079                 ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
1080                                            cinfo, max);
1081                 ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
1082         }
1083         mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
1084         return ret;
1085 }
1086
1087 /*
1088  * Search for an existing write request, and attempt to update
1089  * it to reflect a new dirty region on a given page.
1090  *
1091  * If the attempt fails, then the existing request is flushed out
1092  * to disk.
1093  */
1094 static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
1095                 struct page *page,
1096                 unsigned int offset,
1097                 unsigned int bytes)
1098 {
1099         struct nfs_page *req;
1100         unsigned int rqend;
1101         unsigned int end;
1102         int error;
1103
1104         end = offset + bytes;
1105
1106         req = nfs_lock_and_join_requests(page);
1107         if (IS_ERR_OR_NULL(req))
1108                 return req;
1109
1110         rqend = req->wb_offset + req->wb_bytes;
1111         /*
1112          * Tell the caller to flush out the request if
1113          * the offsets are non-contiguous.
1114          * Note: nfs_flush_incompatible() will already
1115          * have flushed out requests having wrong owners.
1116          */
1117         if (offset > rqend || end < req->wb_offset)
1118                 goto out_flushme;
1119
1120         /* Okay, the request matches. Update the region */
1121         if (offset < req->wb_offset) {
1122                 req->wb_offset = offset;
1123                 req->wb_pgbase = offset;
1124         }
1125         if (end > rqend)
1126                 req->wb_bytes = end - req->wb_offset;
1127         else
1128                 req->wb_bytes = rqend - req->wb_offset;
1129         req->wb_nio = 0;
1130         return req;
1131 out_flushme:
1132         /*
1133          * Note: we mark the request dirty here because
1134          * nfs_lock_and_join_requests() cannot preserve
1135          * commit flags, so we have to replay the write.
1136          */
1137         nfs_mark_request_dirty(req);
1138         nfs_unlock_and_release_request(req);
1139         error = nfs_wb_page(inode, page);
1140         return (error < 0) ? ERR_PTR(error) : NULL;
1141 }
1142
1143 /*
1144  * Try to update an existing write request, or create one if there is none.
1145  *
1146  * Note: Should always be called with the Page Lock held to prevent races
1147  * if we have to add a new request. Also assumes that the caller has
1148  * already called nfs_flush_incompatible() if necessary.
1149  */
1150 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx,
1151                 struct page *page, unsigned int offset, unsigned int bytes)
1152 {
1153         struct inode *inode = page_file_mapping(page)->host;
1154         struct nfs_page *req;
1155
1156         req = nfs_try_to_update_request(inode, page, offset, bytes);
1157         if (req != NULL)
1158                 goto out;
1159         req = nfs_create_request(ctx, page, offset, bytes);
1160         if (IS_ERR(req))
1161                 goto out;
1162         nfs_inode_add_request(inode, req);
1163 out:
1164         return req;
1165 }
1166
1167 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page,
1168                 unsigned int offset, unsigned int count)
1169 {
1170         struct nfs_page *req;
1171
1172         req = nfs_setup_write_request(ctx, page, offset, count);
1173         if (IS_ERR(req))
1174                 return PTR_ERR(req);
1175         /* Update file length */
1176         nfs_grow_file(page, offset, count);
1177         nfs_mark_uptodate(req);
1178         nfs_mark_request_dirty(req);
1179         nfs_unlock_and_release_request(req);
1180         return 0;
1181 }
1182
1183 int nfs_flush_incompatible(struct file *file, struct page *page)
1184 {
1185         struct nfs_open_context *ctx = nfs_file_open_context(file);
1186         struct nfs_lock_context *l_ctx;
1187         struct file_lock_context *flctx = file_inode(file)->i_flctx;
1188         struct nfs_page *req;
1189         int do_flush, status;
1190         /*
1191          * Look for a request corresponding to this page. If there
1192          * is one, and it belongs to another file, we flush it out
1193          * before we try to copy anything into the page. Do this
1194          * due to the lack of an ACCESS-type call in NFSv2.
1195          * Also do the same if we find a request from an existing
1196          * dropped page.
1197          */
1198         do {
1199                 req = nfs_page_find_head_request(page);
1200                 if (req == NULL)
1201                         return 0;
1202                 l_ctx = req->wb_lock_context;
1203                 do_flush = req->wb_page != page ||
1204                         !nfs_match_open_context(nfs_req_openctx(req), ctx);
1205                 if (l_ctx && flctx &&
1206                     !(list_empty_careful(&flctx->flc_posix) &&
1207                       list_empty_careful(&flctx->flc_flock))) {
1208                         do_flush |= l_ctx->lockowner != current->files;
1209                 }
1210                 nfs_release_request(req);
1211                 if (!do_flush)
1212                         return 0;
1213                 status = nfs_wb_page(page_file_mapping(page)->host, page);
1214         } while (status == 0);
1215         return status;
1216 }
1217
1218 /*
1219  * Avoid buffered writes when a open context credential's key would
1220  * expire soon.
1221  *
1222  * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
1223  *
1224  * Return 0 and set a credential flag which triggers the inode to flush
1225  * and performs  NFS_FILE_SYNC writes if the key will expired within
1226  * RPC_KEY_EXPIRE_TIMEO.
1227  */
1228 int
1229 nfs_key_timeout_notify(struct file *filp, struct inode *inode)
1230 {
1231         struct nfs_open_context *ctx = nfs_file_open_context(filp);
1232
1233         if (nfs_ctx_key_to_expire(ctx, inode) &&
1234             !rcu_access_pointer(ctx->ll_cred))
1235                 /* Already expired! */
1236                 return -EACCES;
1237         return 0;
1238 }
1239
1240 /*
1241  * Test if the open context credential key is marked to expire soon.
1242  */
1243 bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx, struct inode *inode)
1244 {
1245         struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
1246         struct rpc_cred *cred, *new, *old = NULL;
1247         struct auth_cred acred = {
1248                 .cred = ctx->cred,
1249         };
1250         bool ret = false;
1251
1252         rcu_read_lock();
1253         cred = rcu_dereference(ctx->ll_cred);
1254         if (cred && !(cred->cr_ops->crkey_timeout &&
1255                       cred->cr_ops->crkey_timeout(cred)))
1256                 goto out;
1257         rcu_read_unlock();
1258
1259         new = auth->au_ops->lookup_cred(auth, &acred, 0);
1260         if (new == cred) {
1261                 put_rpccred(new);
1262                 return true;
1263         }
1264         if (IS_ERR_OR_NULL(new)) {
1265                 new = NULL;
1266                 ret = true;
1267         } else if (new->cr_ops->crkey_timeout &&
1268                    new->cr_ops->crkey_timeout(new))
1269                 ret = true;
1270
1271         rcu_read_lock();
1272         old = rcu_dereference_protected(xchg(&ctx->ll_cred,
1273                                              RCU_INITIALIZER(new)), 1);
1274 out:
1275         rcu_read_unlock();
1276         put_rpccred(old);
1277         return ret;
1278 }
1279
1280 /*
1281  * If the page cache is marked as unsafe or invalid, then we can't rely on
1282  * the PageUptodate() flag. In this case, we will need to turn off
1283  * write optimisations that depend on the page contents being correct.
1284  */
1285 static bool nfs_write_pageuptodate(struct page *page, struct inode *inode,
1286                                    unsigned int pagelen)
1287 {
1288         struct nfs_inode *nfsi = NFS_I(inode);
1289
1290         if (nfs_have_delegated_attributes(inode))
1291                 goto out;
1292         if (nfsi->cache_validity &
1293             (NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE))
1294                 return false;
1295         smp_rmb();
1296         if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags) && pagelen != 0)
1297                 return false;
1298 out:
1299         if (nfsi->cache_validity & NFS_INO_INVALID_DATA && pagelen != 0)
1300                 return false;
1301         return PageUptodate(page) != 0;
1302 }
1303
1304 static bool
1305 is_whole_file_wrlock(struct file_lock *fl)
1306 {
1307         return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
1308                         fl->fl_type == F_WRLCK;
1309 }
1310
1311 /* If we know the page is up to date, and we're not using byte range locks (or
1312  * if we have the whole file locked for writing), it may be more efficient to
1313  * extend the write to cover the entire page in order to avoid fragmentation
1314  * inefficiencies.
1315  *
1316  * If the file is opened for synchronous writes then we can just skip the rest
1317  * of the checks.
1318  */
1319 static int nfs_can_extend_write(struct file *file, struct page *page,
1320                                 struct inode *inode, unsigned int pagelen)
1321 {
1322         int ret;
1323         struct file_lock_context *flctx = inode->i_flctx;
1324         struct file_lock *fl;
1325
1326         if (file->f_flags & O_DSYNC)
1327                 return 0;
1328         if (!nfs_write_pageuptodate(page, inode, pagelen))
1329                 return 0;
1330         if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
1331                 return 1;
1332         if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
1333                        list_empty_careful(&flctx->flc_posix)))
1334                 return 1;
1335
1336         /* Check to see if there are whole file write locks */
1337         ret = 0;
1338         spin_lock(&flctx->flc_lock);
1339         if (!list_empty(&flctx->flc_posix)) {
1340                 fl = list_first_entry(&flctx->flc_posix, struct file_lock,
1341                                         fl_list);
1342                 if (is_whole_file_wrlock(fl))
1343                         ret = 1;
1344         } else if (!list_empty(&flctx->flc_flock)) {
1345                 fl = list_first_entry(&flctx->flc_flock, struct file_lock,
1346                                         fl_list);
1347                 if (fl->fl_type == F_WRLCK)
1348                         ret = 1;
1349         }
1350         spin_unlock(&flctx->flc_lock);
1351         return ret;
1352 }
1353
1354 /*
1355  * Update and possibly write a cached page of an NFS file.
1356  *
1357  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
1358  * things with a page scheduled for an RPC call (e.g. invalidate it).
1359  */
1360 int nfs_updatepage(struct file *file, struct page *page,
1361                 unsigned int offset, unsigned int count)
1362 {
1363         struct nfs_open_context *ctx = nfs_file_open_context(file);
1364         struct address_space *mapping = page_file_mapping(page);
1365         struct inode    *inode = mapping->host;
1366         unsigned int    pagelen = nfs_page_length(page);
1367         int             status = 0;
1368
1369         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
1370
1371         dprintk("NFS:       nfs_updatepage(%pD2 %d@%lld)\n",
1372                 file, count, (long long)(page_file_offset(page) + offset));
1373
1374         if (!count)
1375                 goto out;
1376
1377         if (nfs_can_extend_write(file, page, inode, pagelen)) {
1378                 count = max(count + offset, pagelen);
1379                 offset = 0;
1380         }
1381
1382         status = nfs_writepage_setup(ctx, page, offset, count);
1383         if (status < 0)
1384                 nfs_set_pageerror(mapping);
1385 out:
1386         dprintk("NFS:       nfs_updatepage returns %d (isize %lld)\n",
1387                         status, (long long)i_size_read(inode));
1388         return status;
1389 }
1390
1391 static int flush_task_priority(int how)
1392 {
1393         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
1394                 case FLUSH_HIGHPRI:
1395                         return RPC_PRIORITY_HIGH;
1396                 case FLUSH_LOWPRI:
1397                         return RPC_PRIORITY_LOW;
1398         }
1399         return RPC_PRIORITY_NORMAL;
1400 }
1401
1402 static void nfs_initiate_write(struct nfs_pgio_header *hdr,
1403                                struct rpc_message *msg,
1404                                const struct nfs_rpc_ops *rpc_ops,
1405                                struct rpc_task_setup *task_setup_data, int how)
1406 {
1407         int priority = flush_task_priority(how);
1408
1409         if (IS_SWAPFILE(hdr->inode))
1410                 task_setup_data->flags |= RPC_TASK_SWAPPER;
1411         task_setup_data->priority = priority;
1412         rpc_ops->write_setup(hdr, msg, &task_setup_data->rpc_client);
1413         trace_nfs_initiate_write(hdr);
1414 }
1415
1416 /* If a nfs_flush_* function fails, it should remove reqs from @head and
1417  * call this on each, which will prepare them to be retried on next
1418  * writeback using standard nfs.
1419  */
1420 static void nfs_redirty_request(struct nfs_page *req)
1421 {
1422         /* Bump the transmission count */
1423         req->wb_nio++;
1424         nfs_mark_request_dirty(req);
1425         set_bit(NFS_CONTEXT_RESEND_WRITES, &nfs_req_openctx(req)->flags);
1426         nfs_end_page_writeback(req);
1427         nfs_release_request(req);
1428 }
1429
1430 static void nfs_async_write_error(struct list_head *head, int error)
1431 {
1432         struct nfs_page *req;
1433
1434         while (!list_empty(head)) {
1435                 req = nfs_list_entry(head->next);
1436                 nfs_list_remove_request(req);
1437                 if (nfs_error_is_fatal_on_server(error))
1438                         nfs_write_error(req, error);
1439                 else
1440                         nfs_redirty_request(req);
1441         }
1442 }
1443
1444 static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
1445 {
1446         nfs_async_write_error(&hdr->pages, 0);
1447         filemap_fdatawrite_range(hdr->inode->i_mapping, hdr->args.offset,
1448                         hdr->args.offset + hdr->args.count - 1);
1449 }
1450
1451 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1452         .init_hdr = nfs_async_write_init,
1453         .error_cleanup = nfs_async_write_error,
1454         .completion = nfs_write_completion,
1455         .reschedule_io = nfs_async_write_reschedule_io,
1456 };
1457
1458 void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1459                                struct inode *inode, int ioflags, bool force_mds,
1460                                const struct nfs_pgio_completion_ops *compl_ops)
1461 {
1462         struct nfs_server *server = NFS_SERVER(inode);
1463         const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
1464
1465 #ifdef CONFIG_NFS_V4_1
1466         if (server->pnfs_curr_ld && !force_mds)
1467                 pg_ops = server->pnfs_curr_ld->pg_write_ops;
1468 #endif
1469         nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
1470                         server->wsize, ioflags);
1471 }
1472 EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1473
1474 void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1475 {
1476         struct nfs_pgio_mirror *mirror;
1477
1478         if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
1479                 pgio->pg_ops->pg_cleanup(pgio);
1480
1481         pgio->pg_ops = &nfs_pgio_rw_ops;
1482
1483         nfs_pageio_stop_mirroring(pgio);
1484
1485         mirror = &pgio->pg_mirrors[0];
1486         mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1487 }
1488 EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1489
1490
1491 void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1492 {
1493         struct nfs_commit_data *data = calldata;
1494
1495         NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1496 }
1497
1498 /*
1499  * Special version of should_remove_suid() that ignores capabilities.
1500  */
1501 static int nfs_should_remove_suid(const struct inode *inode)
1502 {
1503         umode_t mode = inode->i_mode;
1504         int kill = 0;
1505
1506         /* suid always must be killed */
1507         if (unlikely(mode & S_ISUID))
1508                 kill = ATTR_KILL_SUID;
1509
1510         /*
1511          * sgid without any exec bits is just a mandatory locking mark; leave
1512          * it alone.  If some exec bits are set, it's a real sgid; kill it.
1513          */
1514         if (unlikely((mode & S_ISGID) && (mode & S_IXGRP)))
1515                 kill |= ATTR_KILL_SGID;
1516
1517         if (unlikely(kill && S_ISREG(mode)))
1518                 return kill;
1519
1520         return 0;
1521 }
1522
1523 static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
1524                 struct nfs_fattr *fattr)
1525 {
1526         struct nfs_pgio_args *argp = &hdr->args;
1527         struct nfs_pgio_res *resp = &hdr->res;
1528         u64 size = argp->offset + resp->count;
1529
1530         if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
1531                 fattr->size = size;
1532         if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
1533                 fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
1534                 return;
1535         }
1536         if (size != fattr->size)
1537                 return;
1538         /* Set attribute barrier */
1539         nfs_fattr_set_barrier(fattr);
1540         /* ...and update size */
1541         fattr->valid |= NFS_ATTR_FATTR_SIZE;
1542 }
1543
1544 void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
1545 {
1546         struct nfs_fattr *fattr = &hdr->fattr;
1547         struct inode *inode = hdr->inode;
1548
1549         spin_lock(&inode->i_lock);
1550         nfs_writeback_check_extend(hdr, fattr);
1551         nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
1552         spin_unlock(&inode->i_lock);
1553 }
1554 EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
1555
1556 /*
1557  * This function is called when the WRITE call is complete.
1558  */
1559 static int nfs_writeback_done(struct rpc_task *task,
1560                               struct nfs_pgio_header *hdr,
1561                               struct inode *inode)
1562 {
1563         int status;
1564
1565         /*
1566          * ->write_done will attempt to use post-op attributes to detect
1567          * conflicting writes by other clients.  A strict interpretation
1568          * of close-to-open would allow us to continue caching even if
1569          * another writer had changed the file, but some applications
1570          * depend on tighter cache coherency when writing.
1571          */
1572         status = NFS_PROTO(inode)->write_done(task, hdr);
1573         if (status != 0)
1574                 return status;
1575
1576         nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
1577         trace_nfs_writeback_done(task, hdr);
1578
1579         if (hdr->res.verf->committed < hdr->args.stable &&
1580             task->tk_status >= 0) {
1581                 /* We tried a write call, but the server did not
1582                  * commit data to stable storage even though we
1583                  * requested it.
1584                  * Note: There is a known bug in Tru64 < 5.0 in which
1585                  *       the server reports NFS_DATA_SYNC, but performs
1586                  *       NFS_FILE_SYNC. We therefore implement this checking
1587                  *       as a dprintk() in order to avoid filling syslog.
1588                  */
1589                 static unsigned long    complain;
1590
1591                 /* Note this will print the MDS for a DS write */
1592                 if (time_before(complain, jiffies)) {
1593                         dprintk("NFS:       faulty NFS server %s:"
1594                                 " (committed = %d) != (stable = %d)\n",
1595                                 NFS_SERVER(inode)->nfs_client->cl_hostname,
1596                                 hdr->res.verf->committed, hdr->args.stable);
1597                         complain = jiffies + 300 * HZ;
1598                 }
1599         }
1600
1601         /* Deal with the suid/sgid bit corner case */
1602         if (nfs_should_remove_suid(inode)) {
1603                 spin_lock(&inode->i_lock);
1604                 nfs_set_cache_invalid(inode, NFS_INO_INVALID_MODE);
1605                 spin_unlock(&inode->i_lock);
1606         }
1607         return 0;
1608 }
1609
1610 /*
1611  * This function is called when the WRITE call is complete.
1612  */
1613 static void nfs_writeback_result(struct rpc_task *task,
1614                                  struct nfs_pgio_header *hdr)
1615 {
1616         struct nfs_pgio_args    *argp = &hdr->args;
1617         struct nfs_pgio_res     *resp = &hdr->res;
1618
1619         if (resp->count < argp->count) {
1620                 static unsigned long    complain;
1621
1622                 /* This a short write! */
1623                 nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
1624
1625                 /* Has the server at least made some progress? */
1626                 if (resp->count == 0) {
1627                         if (time_before(complain, jiffies)) {
1628                                 printk(KERN_WARNING
1629                                        "NFS: Server wrote zero bytes, expected %u.\n",
1630                                        argp->count);
1631                                 complain = jiffies + 300 * HZ;
1632                         }
1633                         nfs_set_pgio_error(hdr, -EIO, argp->offset);
1634                         task->tk_status = -EIO;
1635                         return;
1636                 }
1637
1638                 /* For non rpc-based layout drivers, retry-through-MDS */
1639                 if (!task->tk_ops) {
1640                         hdr->pnfs_error = -EAGAIN;
1641                         return;
1642                 }
1643
1644                 /* Was this an NFSv2 write or an NFSv3 stable write? */
1645                 if (resp->verf->committed != NFS_UNSTABLE) {
1646                         /* Resend from where the server left off */
1647                         hdr->mds_offset += resp->count;
1648                         argp->offset += resp->count;
1649                         argp->pgbase += resp->count;
1650                         argp->count -= resp->count;
1651                 } else {
1652                         /* Resend as a stable write in order to avoid
1653                          * headaches in the case of a server crash.
1654                          */
1655                         argp->stable = NFS_FILE_SYNC;
1656                 }
1657                 resp->count = 0;
1658                 resp->verf->committed = 0;
1659                 rpc_restart_call_prepare(task);
1660         }
1661 }
1662
1663 static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
1664 {
1665         return wait_var_event_killable(&cinfo->rpcs_out,
1666                                        !atomic_read(&cinfo->rpcs_out));
1667 }
1668
1669 static void nfs_commit_begin(struct nfs_mds_commit_info *cinfo)
1670 {
1671         atomic_inc(&cinfo->rpcs_out);
1672 }
1673
1674 bool nfs_commit_end(struct nfs_mds_commit_info *cinfo)
1675 {
1676         if (atomic_dec_and_test(&cinfo->rpcs_out)) {
1677                 wake_up_var(&cinfo->rpcs_out);
1678                 return true;
1679         }
1680         return false;
1681 }
1682
1683 void nfs_commitdata_release(struct nfs_commit_data *data)
1684 {
1685         put_nfs_open_context(data->context);
1686         nfs_commit_free(data);
1687 }
1688 EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1689
1690 int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1691                         const struct nfs_rpc_ops *nfs_ops,
1692                         const struct rpc_call_ops *call_ops,
1693                         int how, int flags)
1694 {
1695         struct rpc_task *task;
1696         int priority = flush_task_priority(how);
1697         struct rpc_message msg = {
1698                 .rpc_argp = &data->args,
1699                 .rpc_resp = &data->res,
1700                 .rpc_cred = data->cred,
1701         };
1702         struct rpc_task_setup task_setup_data = {
1703                 .task = &data->task,
1704                 .rpc_client = clnt,
1705                 .rpc_message = &msg,
1706                 .callback_ops = call_ops,
1707                 .callback_data = data,
1708                 .workqueue = nfsiod_workqueue,
1709                 .flags = RPC_TASK_ASYNC | flags,
1710                 .priority = priority,
1711         };
1712
1713         if (nfs_server_capable(data->inode, NFS_CAP_MOVEABLE))
1714                 task_setup_data.flags |= RPC_TASK_MOVEABLE;
1715
1716         /* Set up the initial task struct.  */
1717         nfs_ops->commit_setup(data, &msg, &task_setup_data.rpc_client);
1718         trace_nfs_initiate_commit(data);
1719
1720         dprintk("NFS: initiated commit call\n");
1721
1722         task = rpc_run_task(&task_setup_data);
1723         if (IS_ERR(task))
1724                 return PTR_ERR(task);
1725         if (how & FLUSH_SYNC)
1726                 rpc_wait_for_completion_task(task);
1727         rpc_put_task(task);
1728         return 0;
1729 }
1730 EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1731
1732 static loff_t nfs_get_lwb(struct list_head *head)
1733 {
1734         loff_t lwb = 0;
1735         struct nfs_page *req;
1736
1737         list_for_each_entry(req, head, wb_list)
1738                 if (lwb < (req_offset(req) + req->wb_bytes))
1739                         lwb = req_offset(req) + req->wb_bytes;
1740
1741         return lwb;
1742 }
1743
1744 /*
1745  * Set up the argument/result storage required for the RPC call.
1746  */
1747 void nfs_init_commit(struct nfs_commit_data *data,
1748                      struct list_head *head,
1749                      struct pnfs_layout_segment *lseg,
1750                      struct nfs_commit_info *cinfo)
1751 {
1752         struct nfs_page *first;
1753         struct nfs_open_context *ctx;
1754         struct inode *inode;
1755
1756         /* Set up the RPC argument and reply structs
1757          * NB: take care not to mess about with data->commit et al. */
1758
1759         if (head)
1760                 list_splice_init(head, &data->pages);
1761
1762         first = nfs_list_entry(data->pages.next);
1763         ctx = nfs_req_openctx(first);
1764         inode = d_inode(ctx->dentry);
1765
1766         data->inode       = inode;
1767         data->cred        = ctx->cred;
1768         data->lseg        = lseg; /* reference transferred */
1769         /* only set lwb for pnfs commit */
1770         if (lseg)
1771                 data->lwb = nfs_get_lwb(&data->pages);
1772         data->mds_ops     = &nfs_commit_ops;
1773         data->completion_ops = cinfo->completion_ops;
1774         data->dreq        = cinfo->dreq;
1775
1776         data->args.fh     = NFS_FH(data->inode);
1777         /* Note: we always request a commit of the entire inode */
1778         data->args.offset = 0;
1779         data->args.count  = 0;
1780         data->context     = get_nfs_open_context(ctx);
1781         data->res.fattr   = &data->fattr;
1782         data->res.verf    = &data->verf;
1783         nfs_fattr_init(&data->fattr);
1784         nfs_commit_begin(cinfo->mds);
1785 }
1786 EXPORT_SYMBOL_GPL(nfs_init_commit);
1787
1788 void nfs_retry_commit(struct list_head *page_list,
1789                       struct pnfs_layout_segment *lseg,
1790                       struct nfs_commit_info *cinfo,
1791                       u32 ds_commit_idx)
1792 {
1793         struct nfs_page *req;
1794
1795         while (!list_empty(page_list)) {
1796                 req = nfs_list_entry(page_list->next);
1797                 nfs_list_remove_request(req);
1798                 nfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx);
1799                 if (!cinfo->dreq)
1800                         nfs_clear_page_commit(req->wb_page);
1801                 nfs_unlock_and_release_request(req);
1802         }
1803 }
1804 EXPORT_SYMBOL_GPL(nfs_retry_commit);
1805
1806 static void
1807 nfs_commit_resched_write(struct nfs_commit_info *cinfo,
1808                 struct nfs_page *req)
1809 {
1810         __set_page_dirty_nobuffers(req->wb_page);
1811 }
1812
1813 /*
1814  * Commit dirty pages
1815  */
1816 static int
1817 nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1818                 struct nfs_commit_info *cinfo)
1819 {
1820         struct nfs_commit_data  *data;
1821         unsigned short task_flags = 0;
1822
1823         /* another commit raced with us */
1824         if (list_empty(head))
1825                 return 0;
1826
1827         data = nfs_commitdata_alloc();
1828         if (!data) {
1829                 nfs_retry_commit(head, NULL, cinfo, -1);
1830                 return -ENOMEM;
1831         }
1832
1833         /* Set up the argument struct */
1834         nfs_init_commit(data, head, NULL, cinfo);
1835         if (NFS_SERVER(inode)->nfs_client->cl_minorversion)
1836                 task_flags = RPC_TASK_MOVEABLE;
1837         return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
1838                                    data->mds_ops, how,
1839                                    RPC_TASK_CRED_NOREF | task_flags);
1840 }
1841
1842 /*
1843  * COMMIT call returned
1844  */
1845 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1846 {
1847         struct nfs_commit_data  *data = calldata;
1848
1849         /* Call the NFS version-specific code */
1850         NFS_PROTO(data->inode)->commit_done(task, data);
1851         trace_nfs_commit_done(task, data);
1852 }
1853
1854 static void nfs_commit_release_pages(struct nfs_commit_data *data)
1855 {
1856         const struct nfs_writeverf *verf = data->res.verf;
1857         struct nfs_page *req;
1858         int status = data->task.tk_status;
1859         struct nfs_commit_info cinfo;
1860         struct nfs_server *nfss;
1861
1862         while (!list_empty(&data->pages)) {
1863                 req = nfs_list_entry(data->pages.next);
1864                 nfs_list_remove_request(req);
1865                 if (req->wb_page)
1866                         nfs_clear_page_commit(req->wb_page);
1867
1868                 dprintk("NFS:       commit (%s/%llu %d@%lld)",
1869                         nfs_req_openctx(req)->dentry->d_sb->s_id,
1870                         (unsigned long long)NFS_FILEID(d_inode(nfs_req_openctx(req)->dentry)),
1871                         req->wb_bytes,
1872                         (long long)req_offset(req));
1873                 if (status < 0) {
1874                         if (req->wb_page) {
1875                                 trace_nfs_commit_error(req, status);
1876                                 nfs_mapping_set_error(req->wb_page, status);
1877                                 nfs_inode_remove_request(req);
1878                         }
1879                         dprintk_cont(", error = %d\n", status);
1880                         goto next;
1881                 }
1882
1883                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1884                  * returned by the server against all stored verfs. */
1885                 if (nfs_write_match_verf(verf, req)) {
1886                         /* We have a match */
1887                         if (req->wb_page)
1888                                 nfs_inode_remove_request(req);
1889                         dprintk_cont(" OK\n");
1890                         goto next;
1891                 }
1892                 /* We have a mismatch. Write the page again */
1893                 dprintk_cont(" mismatch\n");
1894                 nfs_mark_request_dirty(req);
1895                 set_bit(NFS_CONTEXT_RESEND_WRITES, &nfs_req_openctx(req)->flags);
1896         next:
1897                 nfs_unlock_and_release_request(req);
1898                 /* Latency breaker */
1899                 cond_resched();
1900         }
1901         nfss = NFS_SERVER(data->inode);
1902         if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
1903                 nfss->write_congested = 0;
1904
1905         nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1906         nfs_commit_end(cinfo.mds);
1907 }
1908
1909 static void nfs_commit_release(void *calldata)
1910 {
1911         struct nfs_commit_data *data = calldata;
1912
1913         data->completion_ops->completion(data);
1914         nfs_commitdata_release(calldata);
1915 }
1916
1917 static const struct rpc_call_ops nfs_commit_ops = {
1918         .rpc_call_prepare = nfs_commit_prepare,
1919         .rpc_call_done = nfs_commit_done,
1920         .rpc_release = nfs_commit_release,
1921 };
1922
1923 static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1924         .completion = nfs_commit_release_pages,
1925         .resched_write = nfs_commit_resched_write,
1926 };
1927
1928 int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1929                             int how, struct nfs_commit_info *cinfo)
1930 {
1931         int status;
1932
1933         status = pnfs_commit_list(inode, head, how, cinfo);
1934         if (status == PNFS_NOT_ATTEMPTED)
1935                 status = nfs_commit_list(inode, head, how, cinfo);
1936         return status;
1937 }
1938
1939 static int __nfs_commit_inode(struct inode *inode, int how,
1940                 struct writeback_control *wbc)
1941 {
1942         LIST_HEAD(head);
1943         struct nfs_commit_info cinfo;
1944         int may_wait = how & FLUSH_SYNC;
1945         int ret, nscan;
1946
1947         how &= ~FLUSH_SYNC;
1948         nfs_init_cinfo_from_inode(&cinfo, inode);
1949         nfs_commit_begin(cinfo.mds);
1950         for (;;) {
1951                 ret = nscan = nfs_scan_commit(inode, &head, &cinfo);
1952                 if (ret <= 0)
1953                         break;
1954                 ret = nfs_generic_commit_list(inode, &head, how, &cinfo);
1955                 if (ret < 0)
1956                         break;
1957                 ret = 0;
1958                 if (wbc && wbc->sync_mode == WB_SYNC_NONE) {
1959                         if (nscan < wbc->nr_to_write)
1960                                 wbc->nr_to_write -= nscan;
1961                         else
1962                                 wbc->nr_to_write = 0;
1963                 }
1964                 if (nscan < INT_MAX)
1965                         break;
1966                 cond_resched();
1967         }
1968         nfs_commit_end(cinfo.mds);
1969         if (ret || !may_wait)
1970                 return ret;
1971         return wait_on_commit(cinfo.mds);
1972 }
1973
1974 int nfs_commit_inode(struct inode *inode, int how)
1975 {
1976         return __nfs_commit_inode(inode, how, NULL);
1977 }
1978 EXPORT_SYMBOL_GPL(nfs_commit_inode);
1979
1980 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1981 {
1982         struct nfs_inode *nfsi = NFS_I(inode);
1983         int flags = FLUSH_SYNC;
1984         int ret = 0;
1985
1986         if (wbc->sync_mode == WB_SYNC_NONE) {
1987                 /* no commits means nothing needs to be done */
1988                 if (!atomic_long_read(&nfsi->commit_info.ncommit))
1989                         goto check_requests_outstanding;
1990
1991                 /* Don't commit yet if this is a non-blocking flush and there
1992                  * are a lot of outstanding writes for this mapping.
1993                  */
1994                 if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
1995                         goto out_mark_dirty;
1996
1997                 /* don't wait for the COMMIT response */
1998                 flags = 0;
1999         }
2000
2001         ret = __nfs_commit_inode(inode, flags, wbc);
2002         if (!ret) {
2003                 if (flags & FLUSH_SYNC)
2004                         return 0;
2005         } else if (atomic_long_read(&nfsi->commit_info.ncommit))
2006                 goto out_mark_dirty;
2007
2008 check_requests_outstanding:
2009         if (!atomic_read(&nfsi->commit_info.rpcs_out))
2010                 return ret;
2011 out_mark_dirty:
2012         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
2013         return ret;
2014 }
2015 EXPORT_SYMBOL_GPL(nfs_write_inode);
2016
2017 /*
2018  * Wrapper for filemap_write_and_wait_range()
2019  *
2020  * Needed for pNFS in order to ensure data becomes visible to the
2021  * client.
2022  */
2023 int nfs_filemap_write_and_wait_range(struct address_space *mapping,
2024                 loff_t lstart, loff_t lend)
2025 {
2026         int ret;
2027
2028         ret = filemap_write_and_wait_range(mapping, lstart, lend);
2029         if (ret == 0)
2030                 ret = pnfs_sync_inode(mapping->host, true);
2031         return ret;
2032 }
2033 EXPORT_SYMBOL_GPL(nfs_filemap_write_and_wait_range);
2034
2035 /*
2036  * flush the inode to disk.
2037  */
2038 int nfs_wb_all(struct inode *inode)
2039 {
2040         int ret;
2041
2042         trace_nfs_writeback_inode_enter(inode);
2043
2044         ret = filemap_write_and_wait(inode->i_mapping);
2045         if (ret)
2046                 goto out;
2047         ret = nfs_commit_inode(inode, FLUSH_SYNC);
2048         if (ret < 0)
2049                 goto out;
2050         pnfs_sync_inode(inode, true);
2051         ret = 0;
2052
2053 out:
2054         trace_nfs_writeback_inode_exit(inode, ret);
2055         return ret;
2056 }
2057 EXPORT_SYMBOL_GPL(nfs_wb_all);
2058
2059 int nfs_wb_folio_cancel(struct inode *inode, struct folio *folio)
2060 {
2061         struct nfs_page *req;
2062         int ret = 0;
2063
2064         folio_wait_writeback(folio);
2065
2066         /* blocking call to cancel all requests and join to a single (head)
2067          * request */
2068         req = nfs_lock_and_join_requests(&folio->page);
2069
2070         if (IS_ERR(req)) {
2071                 ret = PTR_ERR(req);
2072         } else if (req) {
2073                 /* all requests from this folio have been cancelled by
2074                  * nfs_lock_and_join_requests, so just remove the head
2075                  * request from the inode / page_private pointer and
2076                  * release it */
2077                 nfs_inode_remove_request(req);
2078                 nfs_unlock_and_release_request(req);
2079         }
2080
2081         return ret;
2082 }
2083
2084 /*
2085  * Write back all requests on one page - we do this before reading it.
2086  */
2087 int nfs_wb_page(struct inode *inode, struct page *page)
2088 {
2089         loff_t range_start = page_file_offset(page);
2090         loff_t range_end = range_start + (loff_t)(PAGE_SIZE - 1);
2091         struct writeback_control wbc = {
2092                 .sync_mode = WB_SYNC_ALL,
2093                 .nr_to_write = 0,
2094                 .range_start = range_start,
2095                 .range_end = range_end,
2096         };
2097         int ret;
2098
2099         trace_nfs_writeback_page_enter(inode);
2100
2101         for (;;) {
2102                 wait_on_page_writeback(page);
2103                 if (clear_page_dirty_for_io(page)) {
2104                         ret = nfs_writepage_locked(page, &wbc);
2105                         if (ret < 0)
2106                                 goto out_error;
2107                         continue;
2108                 }
2109                 ret = 0;
2110                 if (!PagePrivate(page))
2111                         break;
2112                 ret = nfs_commit_inode(inode, FLUSH_SYNC);
2113                 if (ret < 0)
2114                         goto out_error;
2115         }
2116 out_error:
2117         trace_nfs_writeback_page_exit(inode, ret);
2118         return ret;
2119 }
2120
2121 #ifdef CONFIG_MIGRATION
2122 int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
2123                 struct page *page, enum migrate_mode mode)
2124 {
2125         /*
2126          * If PagePrivate is set, then the page is currently associated with
2127          * an in-progress read or write request. Don't try to migrate it.
2128          *
2129          * FIXME: we could do this in principle, but we'll need a way to ensure
2130          *        that we can safely release the inode reference while holding
2131          *        the page lock.
2132          */
2133         if (PagePrivate(page))
2134                 return -EBUSY;
2135
2136         if (PageFsCache(page)) {
2137                 if (mode == MIGRATE_ASYNC)
2138                         return -EBUSY;
2139                 wait_on_page_fscache(page);
2140         }
2141
2142         return migrate_page(mapping, newpage, page, mode);
2143 }
2144 #endif
2145
2146 int __init nfs_init_writepagecache(void)
2147 {
2148         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
2149                                              sizeof(struct nfs_pgio_header),
2150                                              0, SLAB_HWCACHE_ALIGN,
2151                                              NULL);
2152         if (nfs_wdata_cachep == NULL)
2153                 return -ENOMEM;
2154
2155         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
2156                                                      nfs_wdata_cachep);
2157         if (nfs_wdata_mempool == NULL)
2158                 goto out_destroy_write_cache;
2159
2160         nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
2161                                              sizeof(struct nfs_commit_data),
2162                                              0, SLAB_HWCACHE_ALIGN,
2163                                              NULL);
2164         if (nfs_cdata_cachep == NULL)
2165                 goto out_destroy_write_mempool;
2166
2167         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
2168                                                       nfs_cdata_cachep);
2169         if (nfs_commit_mempool == NULL)
2170                 goto out_destroy_commit_cache;
2171
2172         /*
2173          * NFS congestion size, scale with available memory.
2174          *
2175          *  64MB:    8192k
2176          * 128MB:   11585k
2177          * 256MB:   16384k
2178          * 512MB:   23170k
2179          *   1GB:   32768k
2180          *   2GB:   46340k
2181          *   4GB:   65536k
2182          *   8GB:   92681k
2183          *  16GB:  131072k
2184          *
2185          * This allows larger machines to have larger/more transfers.
2186          * Limit the default to 256M
2187          */
2188         nfs_congestion_kb = (16*int_sqrt(totalram_pages())) << (PAGE_SHIFT-10);
2189         if (nfs_congestion_kb > 256*1024)
2190                 nfs_congestion_kb = 256*1024;
2191
2192         return 0;
2193
2194 out_destroy_commit_cache:
2195         kmem_cache_destroy(nfs_cdata_cachep);
2196 out_destroy_write_mempool:
2197         mempool_destroy(nfs_wdata_mempool);
2198 out_destroy_write_cache:
2199         kmem_cache_destroy(nfs_wdata_cachep);
2200         return -ENOMEM;
2201 }
2202
2203 void nfs_destroy_writepagecache(void)
2204 {
2205         mempool_destroy(nfs_commit_mempool);
2206         kmem_cache_destroy(nfs_cdata_cachep);
2207         mempool_destroy(nfs_wdata_mempool);
2208         kmem_cache_destroy(nfs_wdata_cachep);
2209 }
2210
2211 static const struct nfs_rw_ops nfs_rw_write_ops = {
2212         .rw_alloc_header        = nfs_writehdr_alloc,
2213         .rw_free_header         = nfs_writehdr_free,
2214         .rw_done                = nfs_writeback_done,
2215         .rw_result              = nfs_writeback_result,
2216         .rw_initiate            = nfs_initiate_write,
2217 };