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 #include <linux/filelock.h>
  29
  30 #include <linux/uaccess.h>
  31 #include <linux/sched/mm.h>
  32
  33 #include "delegation.h"
  34 #include "internal.h"
  35 #include "iostat.h"
  36 #include "nfs4_fs.h"
  37 #include "fscache.h"
  38 #include "pnfs.h"
  39
  40 #include "nfstrace.h"
  41
  42 #define NFSDBG_FACILITY         NFSDBG_PAGECACHE
  43
  44 #define MIN_POOL_WRITE          (32)
  45 #define MIN_POOL_COMMIT         (4)
  46
  47 struct nfs_io_completion {
  48         void (*complete)(void *data);
  49         void *data;
  50         struct kref refcount;
  51 };
  52
  53 /*
  54  * Local function declarations
  55  */
  56 static void nfs_redirty_request(struct nfs_page *req);
  57 static const struct rpc_call_ops nfs_commit_ops;
  58 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops;
  59 static const struct nfs_commit_completion_ops nfs_commit_completion_ops;
  60 static const struct nfs_rw_ops nfs_rw_write_ops;
  61 static void nfs_inode_remove_request(struct nfs_page *req);
  62 static void nfs_clear_request_commit(struct nfs_commit_info *cinfo,
  63                                      struct nfs_page *req);
  64 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo,
  65                                       struct inode *inode);
  66 static struct nfs_page *
  67 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
  68                                                 struct folio *folio);
  69
  70 static struct kmem_cache *nfs_wdata_cachep;
  71 static mempool_t *nfs_wdata_mempool;
  72 static struct kmem_cache *nfs_cdata_cachep;
  73 static mempool_t *nfs_commit_mempool;
  74
  75 struct nfs_commit_data *nfs_commitdata_alloc(void)
  76 {
  77         struct nfs_commit_data *p;
  78
  79         p = kmem_cache_zalloc(nfs_cdata_cachep, nfs_io_gfp_mask());
  80         if (!p) {
  81                 p = mempool_alloc(nfs_commit_mempool, GFP_NOWAIT);
  82                 if (!p)
  83                         return NULL;
  84                 memset(p, 0, sizeof(*p));
  85         }
  86         INIT_LIST_HEAD(&p->pages);
  87         return p;
  88 }
  89 EXPORT_SYMBOL_GPL(nfs_commitdata_alloc);
  90
  91 void nfs_commit_free(struct nfs_commit_data *p)
  92 {
  93         mempool_free(p, nfs_commit_mempool);
  94 }
  95 EXPORT_SYMBOL_GPL(nfs_commit_free);
  96
  97 static struct nfs_pgio_header *nfs_writehdr_alloc(void)
  98 {
  99         struct nfs_pgio_header *p;
 100
 101         p = kmem_cache_zalloc(nfs_wdata_cachep, nfs_io_gfp_mask());
 102         if (!p) {
 103                 p = mempool_alloc(nfs_wdata_mempool, GFP_NOWAIT);
 104                 if (!p)
 105                         return NULL;
 106                 memset(p, 0, sizeof(*p));
 107         }
 108         p->rw_mode = FMODE_WRITE;
 109         return p;
 110 }
 111
 112 static void nfs_writehdr_free(struct nfs_pgio_header *hdr)
 113 {
 114         mempool_free(hdr, nfs_wdata_mempool);
 115 }
 116
 117 static struct nfs_io_completion *nfs_io_completion_alloc(gfp_t gfp_flags)
 118 {
 119         return kmalloc(sizeof(struct nfs_io_completion), gfp_flags);
 120 }
 121
 122 static void nfs_io_completion_init(struct nfs_io_completion *ioc,
 123                 void (*complete)(void *), void *data)
 124 {
 125         ioc->complete = complete;
 126         ioc->data = data;
 127         kref_init(&ioc->refcount);
 128 }
 129
 130 static void nfs_io_completion_release(struct kref *kref)
 131 {
 132         struct nfs_io_completion *ioc = container_of(kref,
 133                         struct nfs_io_completion, refcount);
 134         ioc->complete(ioc->data);
 135         kfree(ioc);
 136 }
 137
 138 static void nfs_io_completion_get(struct nfs_io_completion *ioc)
 139 {
 140         if (ioc != NULL)
 141                 kref_get(&ioc->refcount);
 142 }
 143
 144 static void nfs_io_completion_put(struct nfs_io_completion *ioc)
 145 {
 146         if (ioc != NULL)
 147                 kref_put(&ioc->refcount, nfs_io_completion_release);
 148 }
 149
 150 static void
 151 nfs_page_set_inode_ref(struct nfs_page *req, struct inode *inode)
 152 {
 153         if (!test_and_set_bit(PG_INODE_REF, &req->wb_flags)) {
 154                 kref_get(&req->wb_kref);
 155                 atomic_long_inc(&NFS_I(inode)->nrequests);
 156         }
 157 }
 158
 159 static int
 160 nfs_cancel_remove_inode(struct nfs_page *req, struct inode *inode)
 161 {
 162         int ret;
 163
 164         if (!test_bit(PG_REMOVE, &req->wb_flags))
 165                 return 0;
 166         ret = nfs_page_group_lock(req);
 167         if (ret)
 168                 return ret;
 169         if (test_and_clear_bit(PG_REMOVE, &req->wb_flags))
 170                 nfs_page_set_inode_ref(req, inode);
 171         nfs_page_group_unlock(req);
 172         return 0;
 173 }
 174
 175 static struct nfs_page *nfs_folio_private_request(struct folio *folio)
 176 {
 177         return folio_get_private(folio);
 178 }
 179
 180 /**
 181  * nfs_folio_find_private_request - find head request associated with a folio
 182  * @folio: pointer to folio
 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 *nfs_folio_find_private_request(struct folio *folio)
 189 {
 190         struct address_space *mapping = folio_file_mapping(folio);
 191         struct nfs_page *req;
 192
 193         if (!folio_test_private(folio))
 194                 return NULL;
 195         spin_lock(&mapping->i_private_lock);
 196         req = nfs_folio_private_request(folio);
 197         if (req) {
 198                 WARN_ON_ONCE(req->wb_head != req);
 199                 kref_get(&req->wb_kref);
 200         }
 201         spin_unlock(&mapping->i_private_lock);
 202         return req;
 203 }
 204
 205 static struct nfs_page *nfs_folio_find_swap_request(struct folio *folio)
 206 {
 207         struct inode *inode = folio_file_mapping(folio)->host;
 208         struct nfs_inode *nfsi = NFS_I(inode);
 209         struct nfs_page *req = NULL;
 210         if (!folio_test_swapcache(folio))
 211                 return NULL;
 212         mutex_lock(&nfsi->commit_mutex);
 213         if (folio_test_swapcache(folio)) {
 214                 req = nfs_page_search_commits_for_head_request_locked(nfsi,
 215                                                                       folio);
 216                 if (req) {
 217                         WARN_ON_ONCE(req->wb_head != req);
 218                         kref_get(&req->wb_kref);
 219                 }
 220         }
 221         mutex_unlock(&nfsi->commit_mutex);
 222         return req;
 223 }
 224
 225 /**
 226  * nfs_folio_find_head_request - find head request associated with a folio
 227  * @folio: pointer to folio
 228  *
 229  * returns matching head request with reference held, or NULL if not found.
 230  */
 231 static struct nfs_page *nfs_folio_find_head_request(struct folio *folio)
 232 {
 233         struct nfs_page *req;
 234
 235         req = nfs_folio_find_private_request(folio);
 236         if (!req)
 237                 req = nfs_folio_find_swap_request(folio);
 238         return req;
 239 }
 240
 241 static struct nfs_page *nfs_folio_find_and_lock_request(struct folio *folio)
 242 {
 243         struct inode *inode = folio_file_mapping(folio)->host;
 244         struct nfs_page *req, *head;
 245         int ret;
 246
 247         for (;;) {
 248                 req = nfs_folio_find_head_request(folio);
 249                 if (!req)
 250                         return req;
 251                 head = nfs_page_group_lock_head(req);
 252                 if (head != req)
 253                         nfs_release_request(req);
 254                 if (IS_ERR(head))
 255                         return head;
 256                 ret = nfs_cancel_remove_inode(head, inode);
 257                 if (ret < 0) {
 258                         nfs_unlock_and_release_request(head);
 259                         return ERR_PTR(ret);
 260                 }
 261                 /* Ensure that nobody removed the request before we locked it */
 262                 if (head == nfs_folio_private_request(folio))
 263                         break;
 264                 if (folio_test_swapcache(folio))
 265                         break;
 266                 nfs_unlock_and_release_request(head);
 267         }
 268         return head;
 269 }
 270
 271 /* Adjust the file length if we're writing beyond the end */
 272 static void nfs_grow_file(struct folio *folio, unsigned int offset,
 273                           unsigned int count)
 274 {
 275         struct inode *inode = folio_file_mapping(folio)->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) >> folio_shift(folio)) << folio_order(folio);
 282         if (i_size > 0 && folio_index(folio) < end_index)
 283                 goto out;
 284         end = folio_file_pos(folio) + (loff_t)offset + (loff_t)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 folio *folio, int error)
 311 {
 312         struct address_space *mapping = folio_file_mapping(folio);
 313
 314         folio_set_error(folio);
 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         unsigned int len = nfs_folio_length(nfs_page_to_folio(req));
 362         struct nfs_page *tmp;
 363         unsigned int pos = 0;
 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         struct folio *folio = nfs_page_to_folio(req);
 384
 385         if (folio_test_uptodate(folio))
 386                 return;
 387         if (!nfs_page_group_covers_page(req))
 388                 return;
 389         folio_mark_uptodate(folio);
 390 }
 391
 392 static int wb_priority(struct writeback_control *wbc)
 393 {
 394         int ret = 0;
 395
 396         if (wbc->sync_mode == WB_SYNC_ALL)
 397                 ret = FLUSH_COND_STABLE;
 398         return ret;
 399 }
 400
 401 /*
 402  * NFS congestion control
 403  */
 404
 405 int nfs_congestion_kb;
 406
 407 #define NFS_CONGESTION_ON_THRESH        (nfs_congestion_kb >> (PAGE_SHIFT-10))
 408 #define NFS_CONGESTION_OFF_THRESH       \
 409         (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
 410
 411 static void nfs_folio_set_writeback(struct folio *folio)
 412 {
 413         struct nfs_server *nfss = NFS_SERVER(folio_file_mapping(folio)->host);
 414
 415         folio_start_writeback(folio);
 416         if (atomic_long_inc_return(&nfss->writeback) > NFS_CONGESTION_ON_THRESH)
 417                 nfss->write_congested = 1;
 418 }
 419
 420 static void nfs_folio_end_writeback(struct folio *folio)
 421 {
 422         struct nfs_server *nfss = NFS_SERVER(folio_file_mapping(folio)->host);
 423
 424         folio_end_writeback(folio);
 425         if (atomic_long_dec_return(&nfss->writeback) <
 426             NFS_CONGESTION_OFF_THRESH)
 427                 nfss->write_congested = 0;
 428 }
 429
 430 static void nfs_page_end_writeback(struct nfs_page *req)
 431 {
 432         if (nfs_page_group_sync_on_bit(req, PG_WB_END)) {
 433                 nfs_unlock_request(req);
 434                 nfs_folio_end_writeback(nfs_page_to_folio(req));
 435         } else
 436                 nfs_unlock_request(req);
 437 }
 438
 439 /*
 440  * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests
 441  *
 442  * @destroy_list - request list (using wb_this_page) terminated by @old_head
 443  * @old_head - the old head of the list
 444  *
 445  * All subrequests must be locked and removed from all lists, so at this point
 446  * they are only "active" in this function, and possibly in nfs_wait_on_request
 447  * with a reference held by some other context.
 448  */
 449 static void
 450 nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list,
 451                                  struct nfs_page *old_head,
 452                                  struct inode *inode)
 453 {
 454         while (destroy_list) {
 455                 struct nfs_page *subreq = destroy_list;
 456
 457                 destroy_list = (subreq->wb_this_page == old_head) ?
 458                                    NULL : subreq->wb_this_page;
 459
 460                 /* Note: lock subreq in order to change subreq->wb_head */
 461                 nfs_page_set_headlock(subreq);
 462                 WARN_ON_ONCE(old_head != subreq->wb_head);
 463
 464                 /* make sure old group is not used */
 465                 subreq->wb_this_page = subreq;
 466                 subreq->wb_head = subreq;
 467
 468                 clear_bit(PG_REMOVE, &subreq->wb_flags);
 469
 470                 /* Note: races with nfs_page_group_destroy() */
 471                 if (!kref_read(&subreq->wb_kref)) {
 472                         /* Check if we raced with nfs_page_group_destroy() */
 473                         if (test_and_clear_bit(PG_TEARDOWN, &subreq->wb_flags)) {
 474                                 nfs_page_clear_headlock(subreq);
 475                                 nfs_free_request(subreq);
 476                         } else
 477                                 nfs_page_clear_headlock(subreq);
 478                         continue;
 479                 }
 480                 nfs_page_clear_headlock(subreq);
 481
 482                 nfs_release_request(old_head);
 483
 484                 if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) {
 485                         nfs_release_request(subreq);
 486                         atomic_long_dec(&NFS_I(inode)->nrequests);
 487                 }
 488
 489                 /* subreq is now totally disconnected from page group or any
 490                  * write / commit lists. last chance to wake any waiters */
 491                 nfs_unlock_and_release_request(subreq);
 492         }
 493 }
 494
 495 /*
 496  * nfs_join_page_group - destroy subrequests of the head req
 497  * @head: the page used to lookup the "page group" of nfs_page structures
 498  * @inode: Inode to which the request belongs.
 499  *
 500  * This function joins all sub requests to the head request by first
 501  * locking all requests in the group, cancelling any pending operations
 502  * and finally updating the head request to cover the whole range covered by
 503  * the (former) group.  All subrequests are removed from any write or commit
 504  * lists, unlinked from the group and destroyed.
 505  */
 506 void nfs_join_page_group(struct nfs_page *head, struct nfs_commit_info *cinfo,
 507                          struct inode *inode)
 508 {
 509         struct nfs_page *subreq;
 510         struct nfs_page *destroy_list = NULL;
 511         unsigned int pgbase, off, bytes;
 512
 513         pgbase = head->wb_pgbase;
 514         bytes = head->wb_bytes;
 515         off = head->wb_offset;
 516         for (subreq = head->wb_this_page; subreq != head;
 517                         subreq = subreq->wb_this_page) {
 518                 /* Subrequests should always form a contiguous range */
 519                 if (pgbase > subreq->wb_pgbase) {
 520                         off -= pgbase - subreq->wb_pgbase;
 521                         bytes += pgbase - subreq->wb_pgbase;
 522                         pgbase = subreq->wb_pgbase;
 523                 }
 524                 bytes = max(subreq->wb_pgbase + subreq->wb_bytes
 525                                 - pgbase, bytes);
 526         }
 527
 528         /* Set the head request's range to cover the former page group */
 529         head->wb_pgbase = pgbase;
 530         head->wb_bytes = bytes;
 531         head->wb_offset = off;
 532
 533         /* Now that all requests are locked, make sure they aren't on any list.
 534          * Commit list removal accounting is done after locks are dropped */
 535         subreq = head;
 536         do {
 537                 nfs_clear_request_commit(cinfo, subreq);
 538                 subreq = subreq->wb_this_page;
 539         } while (subreq != head);
 540
 541         /* unlink subrequests from head, destroy them later */
 542         if (head->wb_this_page != head) {
 543                 /* destroy list will be terminated by head */
 544                 destroy_list = head->wb_this_page;
 545                 head->wb_this_page = head;
 546         }
 547
 548         nfs_destroy_unlinked_subrequests(destroy_list, head, inode);
 549 }
 550
 551 /*
 552  * nfs_lock_and_join_requests - join all subreqs to the head req
 553  * @folio: the folio used to lookup the "page group" of nfs_page structures
 554  *
 555  * This function joins all sub requests to the head request by first
 556  * locking all requests in the group, cancelling any pending operations
 557  * and finally updating the head request to cover the whole range covered by
 558  * the (former) group.  All subrequests are removed from any write or commit
 559  * lists, unlinked from the group and destroyed.
 560  *
 561  * Returns a locked, referenced pointer to the head request - which after
 562  * this call is guaranteed to be the only request associated with the page.
 563  * Returns NULL if no requests are found for @folio, or a ERR_PTR if an
 564  * error was encountered.
 565  */
 566 static struct nfs_page *nfs_lock_and_join_requests(struct folio *folio)
 567 {
 568         struct inode *inode = folio_file_mapping(folio)->host;
 569         struct nfs_page *head;
 570         struct nfs_commit_info cinfo;
 571         int ret;
 572
 573         nfs_init_cinfo_from_inode(&cinfo, inode);
 574         /*
 575          * A reference is taken only on the head request which acts as a
 576          * reference to the whole page group - the group will not be destroyed
 577          * until the head reference is released.
 578          */
 579         head = nfs_folio_find_and_lock_request(folio);
 580         if (IS_ERR_OR_NULL(head))
 581                 return head;
 582
 583         /* lock each request in the page group */
 584         ret = nfs_page_group_lock_subrequests(head);
 585         if (ret < 0) {
 586                 nfs_unlock_and_release_request(head);
 587                 return ERR_PTR(ret);
 588         }
 589
 590         nfs_join_page_group(head, &cinfo, inode);
 591
 592         return head;
 593 }
 594
 595 static void nfs_write_error(struct nfs_page *req, int error)
 596 {
 597         trace_nfs_write_error(nfs_page_to_inode(req), req, error);
 598         nfs_mapping_set_error(nfs_page_to_folio(req), error);
 599         nfs_inode_remove_request(req);
 600         nfs_page_end_writeback(req);
 601         nfs_release_request(req);
 602 }
 603
 604 /*
 605  * Find an associated nfs write request, and prepare to flush it out
 606  * May return an error if the user signalled nfs_wait_on_request().
 607  */
 608 static int nfs_page_async_flush(struct folio *folio,
 609                                 struct writeback_control *wbc,
 610                                 struct nfs_pageio_descriptor *pgio)
 611 {
 612         struct nfs_page *req;
 613         int ret = 0;
 614
 615         req = nfs_lock_and_join_requests(folio);
 616         if (!req)
 617                 goto out;
 618         ret = PTR_ERR(req);
 619         if (IS_ERR(req))
 620                 goto out;
 621
 622         nfs_folio_set_writeback(folio);
 623         WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags));
 624
 625         /* If there is a fatal error that covers this write, just exit */
 626         ret = pgio->pg_error;
 627         if (nfs_error_is_fatal_on_server(ret))
 628                 goto out_launder;
 629
 630         ret = 0;
 631         if (!nfs_pageio_add_request(pgio, req)) {
 632                 ret = pgio->pg_error;
 633                 /*
 634                  * Remove the problematic req upon fatal errors on the server
 635                  */
 636                 if (nfs_error_is_fatal_on_server(ret))
 637                         goto out_launder;
 638                 if (wbc->sync_mode == WB_SYNC_NONE)
 639                         ret = AOP_WRITEPAGE_ACTIVATE;
 640                 folio_redirty_for_writepage(wbc, folio);
 641                 nfs_redirty_request(req);
 642                 pgio->pg_error = 0;
 643         } else
 644                 nfs_add_stats(folio_file_mapping(folio)->host,
 645                               NFSIOS_WRITEPAGES, 1);
 646 out:
 647         return ret;
 648 out_launder:
 649         nfs_write_error(req, ret);
 650         return 0;
 651 }
 652
 653 static int nfs_do_writepage(struct folio *folio, struct writeback_control *wbc,
 654                             struct nfs_pageio_descriptor *pgio)
 655 {
 656         nfs_pageio_cond_complete(pgio, folio_index(folio));
 657         return nfs_page_async_flush(folio, wbc, pgio);
 658 }
 659
 660 /*
 661  * Write an mmapped page to the server.
 662  */
 663 static int nfs_writepage_locked(struct folio *folio,
 664                                 struct writeback_control *wbc)
 665 {
 666         struct nfs_pageio_descriptor pgio;
 667         struct inode *inode = folio_file_mapping(folio)->host;
 668         int err;
 669
 670         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE);
 671         nfs_pageio_init_write(&pgio, inode, 0, false,
 672                               &nfs_async_write_completion_ops);
 673         err = nfs_do_writepage(folio, wbc, &pgio);
 674         pgio.pg_error = 0;
 675         nfs_pageio_complete(&pgio);
 676         return err;
 677 }
 678
 679 static int nfs_writepages_callback(struct folio *folio,
 680                                    struct writeback_control *wbc, void *data)
 681 {
 682         int ret;
 683
 684         ret = nfs_do_writepage(folio, wbc, data);
 685         if (ret != AOP_WRITEPAGE_ACTIVATE)
 686                 folio_unlock(folio);
 687         return ret;
 688 }
 689
 690 static void nfs_io_completion_commit(void *inode)
 691 {
 692         nfs_commit_inode(inode, 0);
 693 }
 694
 695 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc)
 696 {
 697         struct inode *inode = mapping->host;
 698         struct nfs_pageio_descriptor pgio;
 699         struct nfs_io_completion *ioc = NULL;
 700         unsigned int mntflags = NFS_SERVER(inode)->flags;
 701         int priority = 0;
 702         int err;
 703
 704         if (wbc->sync_mode == WB_SYNC_NONE &&
 705             NFS_SERVER(inode)->write_congested)
 706                 return 0;
 707
 708         nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES);
 709
 710         if (!(mntflags & NFS_MOUNT_WRITE_EAGER) || wbc->for_kupdate ||
 711             wbc->for_background || wbc->for_sync || wbc->for_reclaim) {
 712                 ioc = nfs_io_completion_alloc(GFP_KERNEL);
 713                 if (ioc)
 714                         nfs_io_completion_init(ioc, nfs_io_completion_commit,
 715                                                inode);
 716                 priority = wb_priority(wbc);
 717         }
 718
 719         do {
 720                 nfs_pageio_init_write(&pgio, inode, priority, false,
 721                                       &nfs_async_write_completion_ops);
 722                 pgio.pg_io_completion = ioc;
 723                 err = write_cache_pages(mapping, wbc, nfs_writepages_callback,
 724                                         &pgio);
 725                 pgio.pg_error = 0;
 726                 nfs_pageio_complete(&pgio);
 727                 if (err == -EAGAIN && mntflags & NFS_MOUNT_SOFTERR)
 728                         break;
 729         } while (err < 0 && !nfs_error_is_fatal(err));
 730         nfs_io_completion_put(ioc);
 731
 732         if (err < 0)
 733                 goto out_err;
 734         return 0;
 735 out_err:
 736         return err;
 737 }
 738
 739 /*
 740  * Insert a write request into an inode
 741  */
 742 static void nfs_inode_add_request(struct nfs_page *req)
 743 {
 744         struct folio *folio = nfs_page_to_folio(req);
 745         struct address_space *mapping = folio_file_mapping(folio);
 746         struct nfs_inode *nfsi = NFS_I(mapping->host);
 747
 748         WARN_ON_ONCE(req->wb_this_page != req);
 749
 750         /* Lock the request! */
 751         nfs_lock_request(req);
 752
 753         /*
 754          * Swap-space should not get truncated. Hence no need to plug the race
 755          * with invalidate/truncate.
 756          */
 757         spin_lock(&mapping->i_private_lock);
 758         if (likely(!folio_test_swapcache(folio))) {
 759                 set_bit(PG_MAPPED, &req->wb_flags);
 760                 folio_set_private(folio);
 761                 folio->private = req;
 762         }
 763         spin_unlock(&mapping->i_private_lock);
 764         atomic_long_inc(&nfsi->nrequests);
 765         /* this a head request for a page group - mark it as having an
 766          * extra reference so sub groups can follow suit.
 767          * This flag also informs pgio layer when to bump nrequests when
 768          * adding subrequests. */
 769         WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags));
 770         kref_get(&req->wb_kref);
 771 }
 772
 773 /*
 774  * Remove a write request from an inode
 775  */
 776 static void nfs_inode_remove_request(struct nfs_page *req)
 777 {
 778         struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req));
 779
 780         if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) {
 781                 struct folio *folio = nfs_page_to_folio(req->wb_head);
 782                 struct address_space *mapping = folio_file_mapping(folio);
 783
 784                 spin_lock(&mapping->i_private_lock);
 785                 if (likely(folio && !folio_test_swapcache(folio))) {
 786                         folio->private = NULL;
 787                         folio_clear_private(folio);
 788                         clear_bit(PG_MAPPED, &req->wb_head->wb_flags);
 789                 }
 790                 spin_unlock(&mapping->i_private_lock);
 791         }
 792
 793         if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) {
 794                 atomic_long_dec(&nfsi->nrequests);
 795                 nfs_release_request(req);
 796         }
 797 }
 798
 799 static void nfs_mark_request_dirty(struct nfs_page *req)
 800 {
 801         struct folio *folio = nfs_page_to_folio(req);
 802         if (folio)
 803                 filemap_dirty_folio(folio_mapping(folio), folio);
 804 }
 805
 806 /*
 807  * nfs_page_search_commits_for_head_request_locked
 808  *
 809  * Search through commit lists on @inode for the head request for @folio.
 810  * Must be called while holding the inode (which is cinfo) lock.
 811  *
 812  * Returns the head request if found, or NULL if not found.
 813  */
 814 static struct nfs_page *
 815 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi,
 816                                                 struct folio *folio)
 817 {
 818         struct nfs_page *freq, *t;
 819         struct nfs_commit_info cinfo;
 820         struct inode *inode = &nfsi->vfs_inode;
 821
 822         nfs_init_cinfo_from_inode(&cinfo, inode);
 823
 824         /* search through pnfs commit lists */
 825         freq = pnfs_search_commit_reqs(inode, &cinfo, folio);
 826         if (freq)
 827                 return freq->wb_head;
 828
 829         /* Linearly search the commit list for the correct request */
 830         list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) {
 831                 if (nfs_page_to_folio(freq) == folio)
 832                         return freq->wb_head;
 833         }
 834
 835         return NULL;
 836 }
 837
 838 /**
 839  * nfs_request_add_commit_list_locked - add request to a commit list
 840  * @req: pointer to a struct nfs_page
 841  * @dst: commit list head
 842  * @cinfo: holds list lock and accounting info
 843  *
 844  * This sets the PG_CLEAN bit, updates the cinfo count of
 845  * number of outstanding requests requiring a commit as well as
 846  * the MM page stats.
 847  *
 848  * The caller must hold NFS_I(cinfo->inode)->commit_mutex, and the
 849  * nfs_page lock.
 850  */
 851 void
 852 nfs_request_add_commit_list_locked(struct nfs_page *req, struct list_head *dst,
 853                             struct nfs_commit_info *cinfo)
 854 {
 855         set_bit(PG_CLEAN, &req->wb_flags);
 856         nfs_list_add_request(req, dst);
 857         atomic_long_inc(&cinfo->mds->ncommit);
 858 }
 859 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list_locked);
 860
 861 /**
 862  * nfs_request_add_commit_list - add request to a commit list
 863  * @req: pointer to a struct nfs_page
 864  * @cinfo: holds list lock and accounting info
 865  *
 866  * This sets the PG_CLEAN bit, updates the cinfo count of
 867  * number of outstanding requests requiring a commit as well as
 868  * the MM page stats.
 869  *
 870  * The caller must _not_ hold the cinfo->lock, but must be
 871  * holding the nfs_page lock.
 872  */
 873 void
 874 nfs_request_add_commit_list(struct nfs_page *req, struct nfs_commit_info *cinfo)
 875 {
 876         mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
 877         nfs_request_add_commit_list_locked(req, &cinfo->mds->list, cinfo);
 878         mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
 879         nfs_folio_mark_unstable(nfs_page_to_folio(req), 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 nfs_folio_clear_commit(struct folio *folio)
 939 {
 940         if (folio) {
 941                 long nr = folio_nr_pages(folio);
 942
 943                 node_stat_mod_folio(folio, NR_WRITEBACK, -nr);
 944                 wb_stat_mod(&inode_to_bdi(folio_file_mapping(folio)->host)->wb,
 945                             WB_WRITEBACK, -nr);
 946         }
 947 }
 948
 949 /* Called holding the request lock on @req */
 950 static void nfs_clear_request_commit(struct nfs_commit_info *cinfo,
 951                                      struct nfs_page *req)
 952 {
 953         if (test_bit(PG_CLEAN, &req->wb_flags)) {
 954                 struct nfs_open_context *ctx = nfs_req_openctx(req);
 955                 struct inode *inode = d_inode(ctx->dentry);
 956
 957                 mutex_lock(&NFS_I(inode)->commit_mutex);
 958                 if (!pnfs_clear_request_commit(req, cinfo)) {
 959                         nfs_request_remove_commit_list(req, cinfo);
 960                 }
 961                 mutex_unlock(&NFS_I(inode)->commit_mutex);
 962                 nfs_folio_clear_commit(nfs_page_to_folio(req));
 963         }
 964 }
 965
 966 int nfs_write_need_commit(struct nfs_pgio_header *hdr)
 967 {
 968         if (hdr->verf.committed == NFS_DATA_SYNC)
 969                 return hdr->lseg == NULL;
 970         return hdr->verf.committed != NFS_FILE_SYNC;
 971 }
 972
 973 static void nfs_async_write_init(struct nfs_pgio_header *hdr)
 974 {
 975         nfs_io_completion_get(hdr->io_completion);
 976 }
 977
 978 static void nfs_write_completion(struct nfs_pgio_header *hdr)
 979 {
 980         struct nfs_commit_info cinfo;
 981         unsigned long bytes = 0;
 982
 983         if (test_bit(NFS_IOHDR_REDO, &hdr->flags))
 984                 goto out;
 985         nfs_init_cinfo_from_inode(&cinfo, hdr->inode);
 986         while (!list_empty(&hdr->pages)) {
 987                 struct nfs_page *req = nfs_list_entry(hdr->pages.next);
 988
 989                 bytes += req->wb_bytes;
 990                 nfs_list_remove_request(req);
 991                 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
 992                     (hdr->good_bytes < bytes)) {
 993                         trace_nfs_comp_error(hdr->inode, req, hdr->error);
 994                         nfs_mapping_set_error(nfs_page_to_folio(req),
 995                                               hdr->error);
 996                         goto remove_req;
 997                 }
 998                 if (nfs_write_need_commit(hdr)) {
 999                         /* Reset wb_nio, since the write was successful. */
1000                         req->wb_nio = 0;
1001                         memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf));
1002                         nfs_mark_request_commit(req, hdr->lseg, &cinfo,
1003                                 hdr->pgio_mirror_idx);
1004                         goto next;
1005                 }
1006 remove_req:
1007                 nfs_inode_remove_request(req);
1008 next:
1009                 nfs_page_end_writeback(req);
1010                 nfs_release_request(req);
1011         }
1012 out:
1013         nfs_io_completion_put(hdr->io_completion);
1014         hdr->release(hdr);
1015 }
1016
1017 unsigned long
1018 nfs_reqs_to_commit(struct nfs_commit_info *cinfo)
1019 {
1020         return atomic_long_read(&cinfo->mds->ncommit);
1021 }
1022
1023 /* NFS_I(cinfo->inode)->commit_mutex held by caller */
1024 int
1025 nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
1026                      struct nfs_commit_info *cinfo, int max)
1027 {
1028         struct nfs_page *req, *tmp;
1029         int ret = 0;
1030
1031         list_for_each_entry_safe(req, tmp, src, wb_list) {
1032                 kref_get(&req->wb_kref);
1033                 if (!nfs_lock_request(req)) {
1034                         nfs_release_request(req);
1035                         continue;
1036                 }
1037                 nfs_request_remove_commit_list(req, cinfo);
1038                 clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
1039                 nfs_list_add_request(req, dst);
1040                 ret++;
1041                 if ((ret == max) && !cinfo->dreq)
1042                         break;
1043                 cond_resched();
1044         }
1045         return ret;
1046 }
1047 EXPORT_SYMBOL_GPL(nfs_scan_commit_list);
1048
1049 /*
1050  * nfs_scan_commit - Scan an inode for commit requests
1051  * @inode: NFS inode to scan
1052  * @dst: mds destination list
1053  * @cinfo: mds and ds lists of reqs ready to commit
1054  *
1055  * Moves requests from the inode's 'commit' request list.
1056  * The requests are *not* checked to ensure that they form a contiguous set.
1057  */
1058 int
1059 nfs_scan_commit(struct inode *inode, struct list_head *dst,
1060                 struct nfs_commit_info *cinfo)
1061 {
1062         int ret = 0;
1063
1064         if (!atomic_long_read(&cinfo->mds->ncommit))
1065                 return 0;
1066         mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);
1067         if (atomic_long_read(&cinfo->mds->ncommit) > 0) {
1068                 const int max = INT_MAX;
1069
1070                 ret = nfs_scan_commit_list(&cinfo->mds->list, dst,
1071                                            cinfo, max);
1072                 ret += pnfs_scan_commit_lists(inode, cinfo, max - ret);
1073         }
1074         mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);
1075         return ret;
1076 }
1077
1078 /*
1079  * Search for an existing write request, and attempt to update
1080  * it to reflect a new dirty region on a given page.
1081  *
1082  * If the attempt fails, then the existing request is flushed out
1083  * to disk.
1084  */
1085 static struct nfs_page *nfs_try_to_update_request(struct folio *folio,
1086                                                   unsigned int offset,
1087                                                   unsigned int bytes)
1088 {
1089         struct nfs_page *req;
1090         unsigned int rqend;
1091         unsigned int end;
1092         int error;
1093
1094         end = offset + bytes;
1095
1096         req = nfs_lock_and_join_requests(folio);
1097         if (IS_ERR_OR_NULL(req))
1098                 return req;
1099
1100         rqend = req->wb_offset + req->wb_bytes;
1101         /*
1102          * Tell the caller to flush out the request if
1103          * the offsets are non-contiguous.
1104          * Note: nfs_flush_incompatible() will already
1105          * have flushed out requests having wrong owners.
1106          */
1107         if (offset > rqend || end < req->wb_offset)
1108                 goto out_flushme;
1109
1110         /* Okay, the request matches. Update the region */
1111         if (offset < req->wb_offset) {
1112                 req->wb_offset = offset;
1113                 req->wb_pgbase = offset;
1114         }
1115         if (end > rqend)
1116                 req->wb_bytes = end - req->wb_offset;
1117         else
1118                 req->wb_bytes = rqend - req->wb_offset;
1119         req->wb_nio = 0;
1120         return req;
1121 out_flushme:
1122         /*
1123          * Note: we mark the request dirty here because
1124          * nfs_lock_and_join_requests() cannot preserve
1125          * commit flags, so we have to replay the write.
1126          */
1127         nfs_mark_request_dirty(req);
1128         nfs_unlock_and_release_request(req);
1129         error = nfs_wb_folio(folio_file_mapping(folio)->host, folio);
1130         return (error < 0) ? ERR_PTR(error) : NULL;
1131 }
1132
1133 /*
1134  * Try to update an existing write request, or create one if there is none.
1135  *
1136  * Note: Should always be called with the Page Lock held to prevent races
1137  * if we have to add a new request. Also assumes that the caller has
1138  * already called nfs_flush_incompatible() if necessary.
1139  */
1140 static struct nfs_page *nfs_setup_write_request(struct nfs_open_context *ctx,
1141                                                 struct folio *folio,
1142                                                 unsigned int offset,
1143                                                 unsigned int bytes)
1144 {
1145         struct nfs_page *req;
1146
1147         req = nfs_try_to_update_request(folio, offset, bytes);
1148         if (req != NULL)
1149                 goto out;
1150         req = nfs_page_create_from_folio(ctx, folio, offset, bytes);
1151         if (IS_ERR(req))
1152                 goto out;
1153         nfs_inode_add_request(req);
1154 out:
1155         return req;
1156 }
1157
1158 static int nfs_writepage_setup(struct nfs_open_context *ctx,
1159                                struct folio *folio, unsigned int offset,
1160                                unsigned int count)
1161 {
1162         struct nfs_page *req;
1163
1164         req = nfs_setup_write_request(ctx, folio, offset, count);
1165         if (IS_ERR(req))
1166                 return PTR_ERR(req);
1167         /* Update file length */
1168         nfs_grow_file(folio, offset, count);
1169         nfs_mark_uptodate(req);
1170         nfs_mark_request_dirty(req);
1171         nfs_unlock_and_release_request(req);
1172         return 0;
1173 }
1174
1175 int nfs_flush_incompatible(struct file *file, struct folio *folio)
1176 {
1177         struct nfs_open_context *ctx = nfs_file_open_context(file);
1178         struct nfs_lock_context *l_ctx;
1179         struct file_lock_context *flctx = locks_inode_context(file_inode(file));
1180         struct nfs_page *req;
1181         int do_flush, status;
1182         /*
1183          * Look for a request corresponding to this page. If there
1184          * is one, and it belongs to another file, we flush it out
1185          * before we try to copy anything into the page. Do this
1186          * due to the lack of an ACCESS-type call in NFSv2.
1187          * Also do the same if we find a request from an existing
1188          * dropped page.
1189          */
1190         do {
1191                 req = nfs_folio_find_head_request(folio);
1192                 if (req == NULL)
1193                         return 0;
1194                 l_ctx = req->wb_lock_context;
1195                 do_flush = nfs_page_to_folio(req) != folio ||
1196                            !nfs_match_open_context(nfs_req_openctx(req), ctx);
1197                 if (l_ctx && flctx &&
1198                     !(list_empty_careful(&flctx->flc_posix) &&
1199                       list_empty_careful(&flctx->flc_flock))) {
1200                         do_flush |= l_ctx->lockowner != current->files;
1201                 }
1202                 nfs_release_request(req);
1203                 if (!do_flush)
1204                         return 0;
1205                 status = nfs_wb_folio(folio_file_mapping(folio)->host, folio);
1206         } while (status == 0);
1207         return status;
1208 }
1209
1210 /*
1211  * Avoid buffered writes when a open context credential's key would
1212  * expire soon.
1213  *
1214  * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL.
1215  *
1216  * Return 0 and set a credential flag which triggers the inode to flush
1217  * and performs  NFS_FILE_SYNC writes if the key will expired within
1218  * RPC_KEY_EXPIRE_TIMEO.
1219  */
1220 int
1221 nfs_key_timeout_notify(struct file *filp, struct inode *inode)
1222 {
1223         struct nfs_open_context *ctx = nfs_file_open_context(filp);
1224
1225         if (nfs_ctx_key_to_expire(ctx, inode) &&
1226             !rcu_access_pointer(ctx->ll_cred))
1227                 /* Already expired! */
1228                 return -EACCES;
1229         return 0;
1230 }
1231
1232 /*
1233  * Test if the open context credential key is marked to expire soon.
1234  */
1235 bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx, struct inode *inode)
1236 {
1237         struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth;
1238         struct rpc_cred *cred, *new, *old = NULL;
1239         struct auth_cred acred = {
1240                 .cred = ctx->cred,
1241         };
1242         bool ret = false;
1243
1244         rcu_read_lock();
1245         cred = rcu_dereference(ctx->ll_cred);
1246         if (cred && !(cred->cr_ops->crkey_timeout &&
1247                       cred->cr_ops->crkey_timeout(cred)))
1248                 goto out;
1249         rcu_read_unlock();
1250
1251         new = auth->au_ops->lookup_cred(auth, &acred, 0);
1252         if (new == cred) {
1253                 put_rpccred(new);
1254                 return true;
1255         }
1256         if (IS_ERR_OR_NULL(new)) {
1257                 new = NULL;
1258                 ret = true;
1259         } else if (new->cr_ops->crkey_timeout &&
1260                    new->cr_ops->crkey_timeout(new))
1261                 ret = true;
1262
1263         rcu_read_lock();
1264         old = rcu_dereference_protected(xchg(&ctx->ll_cred,
1265                                              RCU_INITIALIZER(new)), 1);
1266 out:
1267         rcu_read_unlock();
1268         put_rpccred(old);
1269         return ret;
1270 }
1271
1272 /*
1273  * If the page cache is marked as unsafe or invalid, then we can't rely on
1274  * the PageUptodate() flag. In this case, we will need to turn off
1275  * write optimisations that depend on the page contents being correct.
1276  */
1277 static bool nfs_folio_write_uptodate(struct folio *folio, unsigned int pagelen)
1278 {
1279         struct inode *inode = folio_file_mapping(folio)->host;
1280         struct nfs_inode *nfsi = NFS_I(inode);
1281
1282         if (nfs_have_delegated_attributes(inode))
1283                 goto out;
1284         if (nfsi->cache_validity &
1285             (NFS_INO_INVALID_CHANGE | NFS_INO_INVALID_SIZE))
1286                 return false;
1287         smp_rmb();
1288         if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags) && pagelen != 0)
1289                 return false;
1290 out:
1291         if (nfsi->cache_validity & NFS_INO_INVALID_DATA && pagelen != 0)
1292                 return false;
1293         return folio_test_uptodate(folio) != 0;
1294 }
1295
1296 static bool
1297 is_whole_file_wrlock(struct file_lock *fl)
1298 {
1299         return fl->fl_start == 0 && fl->fl_end == OFFSET_MAX &&
1300                         lock_is_write(fl);
1301 }
1302
1303 /* If we know the page is up to date, and we're not using byte range locks (or
1304  * if we have the whole file locked for writing), it may be more efficient to
1305  * extend the write to cover the entire page in order to avoid fragmentation
1306  * inefficiencies.
1307  *
1308  * If the file is opened for synchronous writes then we can just skip the rest
1309  * of the checks.
1310  */
1311 static int nfs_can_extend_write(struct file *file, struct folio *folio,
1312                                 unsigned int pagelen)
1313 {
1314         struct inode *inode = file_inode(file);
1315         struct file_lock_context *flctx = locks_inode_context(inode);
1316         struct file_lock *fl;
1317         int ret;
1318
1319         if (file->f_flags & O_DSYNC)
1320                 return 0;
1321         if (!nfs_folio_write_uptodate(folio, pagelen))
1322                 return 0;
1323         if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
1324                 return 1;
1325         if (!flctx || (list_empty_careful(&flctx->flc_flock) &&
1326                        list_empty_careful(&flctx->flc_posix)))
1327                 return 1;
1328
1329         /* Check to see if there are whole file write locks */
1330         ret = 0;
1331         spin_lock(&flctx->flc_lock);
1332         if (!list_empty(&flctx->flc_posix)) {
1333                 fl = list_first_entry(&flctx->flc_posix, struct file_lock,
1334                                         c.flc_list);
1335                 if (is_whole_file_wrlock(fl))
1336                         ret = 1;
1337         } else if (!list_empty(&flctx->flc_flock)) {
1338                 fl = list_first_entry(&flctx->flc_flock, struct file_lock,
1339                                         c.flc_list);
1340                 if (lock_is_write(fl))
1341                         ret = 1;
1342         }
1343         spin_unlock(&flctx->flc_lock);
1344         return ret;
1345 }
1346
1347 /*
1348  * Update and possibly write a cached page of an NFS file.
1349  *
1350  * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad
1351  * things with a page scheduled for an RPC call (e.g. invalidate it).
1352  */
1353 int nfs_update_folio(struct file *file, struct folio *folio,
1354                      unsigned int offset, unsigned int count)
1355 {
1356         struct nfs_open_context *ctx = nfs_file_open_context(file);
1357         struct address_space *mapping = folio_file_mapping(folio);
1358         struct inode *inode = mapping->host;
1359         unsigned int pagelen = nfs_folio_length(folio);
1360         int             status = 0;
1361
1362         nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
1363
1364         dprintk("NFS:       nfs_update_folio(%pD2 %d@%lld)\n", file, count,
1365                 (long long)(folio_file_pos(folio) + offset));
1366
1367         if (!count)
1368                 goto out;
1369
1370         if (nfs_can_extend_write(file, folio, pagelen)) {
1371                 count = max(count + offset, pagelen);
1372                 offset = 0;
1373         }
1374
1375         status = nfs_writepage_setup(ctx, folio, offset, count);
1376         if (status < 0)
1377                 nfs_set_pageerror(mapping);
1378 out:
1379         dprintk("NFS:       nfs_update_folio returns %d (isize %lld)\n",
1380                         status, (long long)i_size_read(inode));
1381         return status;
1382 }
1383
1384 static int flush_task_priority(int how)
1385 {
1386         switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) {
1387                 case FLUSH_HIGHPRI:
1388                         return RPC_PRIORITY_HIGH;
1389                 case FLUSH_LOWPRI:
1390                         return RPC_PRIORITY_LOW;
1391         }
1392         return RPC_PRIORITY_NORMAL;
1393 }
1394
1395 static void nfs_initiate_write(struct nfs_pgio_header *hdr,
1396                                struct rpc_message *msg,
1397                                const struct nfs_rpc_ops *rpc_ops,
1398                                struct rpc_task_setup *task_setup_data, int how)
1399 {
1400         int priority = flush_task_priority(how);
1401
1402         if (IS_SWAPFILE(hdr->inode))
1403                 task_setup_data->flags |= RPC_TASK_SWAPPER;
1404         task_setup_data->priority = priority;
1405         rpc_ops->write_setup(hdr, msg, &task_setup_data->rpc_client);
1406         trace_nfs_initiate_write(hdr);
1407 }
1408
1409 /* If a nfs_flush_* function fails, it should remove reqs from @head and
1410  * call this on each, which will prepare them to be retried on next
1411  * writeback using standard nfs.
1412  */
1413 static void nfs_redirty_request(struct nfs_page *req)
1414 {
1415         struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req));
1416
1417         /* Bump the transmission count */
1418         req->wb_nio++;
1419         nfs_mark_request_dirty(req);
1420         atomic_long_inc(&nfsi->redirtied_pages);
1421         nfs_page_end_writeback(req);
1422         nfs_release_request(req);
1423 }
1424
1425 static void nfs_async_write_error(struct list_head *head, int error)
1426 {
1427         struct nfs_page *req;
1428
1429         while (!list_empty(head)) {
1430                 req = nfs_list_entry(head->next);
1431                 nfs_list_remove_request(req);
1432                 if (nfs_error_is_fatal_on_server(error))
1433                         nfs_write_error(req, error);
1434                 else
1435                         nfs_redirty_request(req);
1436         }
1437 }
1438
1439 static void nfs_async_write_reschedule_io(struct nfs_pgio_header *hdr)
1440 {
1441         nfs_async_write_error(&hdr->pages, 0);
1442 }
1443
1444 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = {
1445         .init_hdr = nfs_async_write_init,
1446         .error_cleanup = nfs_async_write_error,
1447         .completion = nfs_write_completion,
1448         .reschedule_io = nfs_async_write_reschedule_io,
1449 };
1450
1451 void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio,
1452                                struct inode *inode, int ioflags, bool force_mds,
1453                                const struct nfs_pgio_completion_ops *compl_ops)
1454 {
1455         struct nfs_server *server = NFS_SERVER(inode);
1456         const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops;
1457
1458 #ifdef CONFIG_NFS_V4_1
1459         if (server->pnfs_curr_ld && !force_mds)
1460                 pg_ops = server->pnfs_curr_ld->pg_write_ops;
1461 #endif
1462         nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops,
1463                         server->wsize, ioflags);
1464 }
1465 EXPORT_SYMBOL_GPL(nfs_pageio_init_write);
1466
1467 void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio)
1468 {
1469         struct nfs_pgio_mirror *mirror;
1470
1471         if (pgio->pg_ops && pgio->pg_ops->pg_cleanup)
1472                 pgio->pg_ops->pg_cleanup(pgio);
1473
1474         pgio->pg_ops = &nfs_pgio_rw_ops;
1475
1476         nfs_pageio_stop_mirroring(pgio);
1477
1478         mirror = &pgio->pg_mirrors[0];
1479         mirror->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize;
1480 }
1481 EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds);
1482
1483
1484 void nfs_commit_prepare(struct rpc_task *task, void *calldata)
1485 {
1486         struct nfs_commit_data *data = calldata;
1487
1488         NFS_PROTO(data->inode)->commit_rpc_prepare(task, data);
1489 }
1490
1491 static void nfs_writeback_check_extend(struct nfs_pgio_header *hdr,
1492                 struct nfs_fattr *fattr)
1493 {
1494         struct nfs_pgio_args *argp = &hdr->args;
1495         struct nfs_pgio_res *resp = &hdr->res;
1496         u64 size = argp->offset + resp->count;
1497
1498         if (!(fattr->valid & NFS_ATTR_FATTR_SIZE))
1499                 fattr->size = size;
1500         if (nfs_size_to_loff_t(fattr->size) < i_size_read(hdr->inode)) {
1501                 fattr->valid &= ~NFS_ATTR_FATTR_SIZE;
1502                 return;
1503         }
1504         if (size != fattr->size)
1505                 return;
1506         /* Set attribute barrier */
1507         nfs_fattr_set_barrier(fattr);
1508         /* ...and update size */
1509         fattr->valid |= NFS_ATTR_FATTR_SIZE;
1510 }
1511
1512 void nfs_writeback_update_inode(struct nfs_pgio_header *hdr)
1513 {
1514         struct nfs_fattr *fattr = &hdr->fattr;
1515         struct inode *inode = hdr->inode;
1516
1517         spin_lock(&inode->i_lock);
1518         nfs_writeback_check_extend(hdr, fattr);
1519         nfs_post_op_update_inode_force_wcc_locked(inode, fattr);
1520         spin_unlock(&inode->i_lock);
1521 }
1522 EXPORT_SYMBOL_GPL(nfs_writeback_update_inode);
1523
1524 /*
1525  * This function is called when the WRITE call is complete.
1526  */
1527 static int nfs_writeback_done(struct rpc_task *task,
1528                               struct nfs_pgio_header *hdr,
1529                               struct inode *inode)
1530 {
1531         int status;
1532
1533         /*
1534          * ->write_done will attempt to use post-op attributes to detect
1535          * conflicting writes by other clients.  A strict interpretation
1536          * of close-to-open would allow us to continue caching even if
1537          * another writer had changed the file, but some applications
1538          * depend on tighter cache coherency when writing.
1539          */
1540         status = NFS_PROTO(inode)->write_done(task, hdr);
1541         if (status != 0)
1542                 return status;
1543
1544         nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count);
1545         trace_nfs_writeback_done(task, hdr);
1546
1547         if (task->tk_status >= 0) {
1548                 enum nfs3_stable_how committed = hdr->res.verf->committed;
1549
1550                 if (committed == NFS_UNSTABLE) {
1551                         /*
1552                          * We have some uncommitted data on the server at
1553                          * this point, so ensure that we keep track of that
1554                          * fact irrespective of what later writes do.
1555                          */
1556                         set_bit(NFS_IOHDR_UNSTABLE_WRITES, &hdr->flags);
1557                 }
1558
1559                 if (committed < hdr->args.stable) {
1560                         /* We tried a write call, but the server did not
1561                          * commit data to stable storage even though we
1562                          * requested it.
1563                          * Note: There is a known bug in Tru64 < 5.0 in which
1564                          *       the server reports NFS_DATA_SYNC, but performs
1565                          *       NFS_FILE_SYNC. We therefore implement this checking
1566                          *       as a dprintk() in order to avoid filling syslog.
1567                          */
1568                         static unsigned long    complain;
1569
1570                         /* Note this will print the MDS for a DS write */
1571                         if (time_before(complain, jiffies)) {
1572                                 dprintk("NFS:       faulty NFS server %s:"
1573                                         " (committed = %d) != (stable = %d)\n",
1574                                         NFS_SERVER(inode)->nfs_client->cl_hostname,
1575                                         committed, hdr->args.stable);
1576                                 complain = jiffies + 300 * HZ;
1577                         }
1578                 }
1579         }
1580
1581         /* Deal with the suid/sgid bit corner case */
1582         if (nfs_should_remove_suid(inode)) {
1583                 spin_lock(&inode->i_lock);
1584                 nfs_set_cache_invalid(inode, NFS_INO_INVALID_MODE);
1585                 spin_unlock(&inode->i_lock);
1586         }
1587         return 0;
1588 }
1589
1590 /*
1591  * This function is called when the WRITE call is complete.
1592  */
1593 static void nfs_writeback_result(struct rpc_task *task,
1594                                  struct nfs_pgio_header *hdr)
1595 {
1596         struct nfs_pgio_args    *argp = &hdr->args;
1597         struct nfs_pgio_res     *resp = &hdr->res;
1598
1599         if (resp->count < argp->count) {
1600                 static unsigned long    complain;
1601
1602                 /* This a short write! */
1603                 nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE);
1604
1605                 /* Has the server at least made some progress? */
1606                 if (resp->count == 0) {
1607                         if (time_before(complain, jiffies)) {
1608                                 printk(KERN_WARNING
1609                                        "NFS: Server wrote zero bytes, expected %u.\n",
1610                                        argp->count);
1611                                 complain = jiffies + 300 * HZ;
1612                         }
1613                         nfs_set_pgio_error(hdr, -EIO, argp->offset);
1614                         task->tk_status = -EIO;
1615                         return;
1616                 }
1617
1618                 /* For non rpc-based layout drivers, retry-through-MDS */
1619                 if (!task->tk_ops) {
1620                         hdr->pnfs_error = -EAGAIN;
1621                         return;
1622                 }
1623
1624                 /* Was this an NFSv2 write or an NFSv3 stable write? */
1625                 if (resp->verf->committed != NFS_UNSTABLE) {
1626                         /* Resend from where the server left off */
1627                         hdr->mds_offset += resp->count;
1628                         argp->offset += resp->count;
1629                         argp->pgbase += resp->count;
1630                         argp->count -= resp->count;
1631                 } else {
1632                         /* Resend as a stable write in order to avoid
1633                          * headaches in the case of a server crash.
1634                          */
1635                         argp->stable = NFS_FILE_SYNC;
1636                 }
1637                 resp->count = 0;
1638                 resp->verf->committed = 0;
1639                 rpc_restart_call_prepare(task);
1640         }
1641 }
1642
1643 static int wait_on_commit(struct nfs_mds_commit_info *cinfo)
1644 {
1645         return wait_var_event_killable(&cinfo->rpcs_out,
1646                                        !atomic_read(&cinfo->rpcs_out));
1647 }
1648
1649 void nfs_commit_begin(struct nfs_mds_commit_info *cinfo)
1650 {
1651         atomic_inc(&cinfo->rpcs_out);
1652 }
1653
1654 bool nfs_commit_end(struct nfs_mds_commit_info *cinfo)
1655 {
1656         if (atomic_dec_and_test(&cinfo->rpcs_out)) {
1657                 wake_up_var(&cinfo->rpcs_out);
1658                 return true;
1659         }
1660         return false;
1661 }
1662
1663 void nfs_commitdata_release(struct nfs_commit_data *data)
1664 {
1665         put_nfs_open_context(data->context);
1666         nfs_commit_free(data);
1667 }
1668 EXPORT_SYMBOL_GPL(nfs_commitdata_release);
1669
1670 int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data,
1671                         const struct nfs_rpc_ops *nfs_ops,
1672                         const struct rpc_call_ops *call_ops,
1673                         int how, int flags)
1674 {
1675         struct rpc_task *task;
1676         int priority = flush_task_priority(how);
1677         struct rpc_message msg = {
1678                 .rpc_argp = &data->args,
1679                 .rpc_resp = &data->res,
1680                 .rpc_cred = data->cred,
1681         };
1682         struct rpc_task_setup task_setup_data = {
1683                 .task = &data->task,
1684                 .rpc_client = clnt,
1685                 .rpc_message = &msg,
1686                 .callback_ops = call_ops,
1687                 .callback_data = data,
1688                 .workqueue = nfsiod_workqueue,
1689                 .flags = RPC_TASK_ASYNC | flags,
1690                 .priority = priority,
1691         };
1692
1693         if (nfs_server_capable(data->inode, NFS_CAP_MOVEABLE))
1694                 task_setup_data.flags |= RPC_TASK_MOVEABLE;
1695
1696         /* Set up the initial task struct.  */
1697         nfs_ops->commit_setup(data, &msg, &task_setup_data.rpc_client);
1698         trace_nfs_initiate_commit(data);
1699
1700         dprintk("NFS: initiated commit call\n");
1701
1702         task = rpc_run_task(&task_setup_data);
1703         if (IS_ERR(task))
1704                 return PTR_ERR(task);
1705         if (how & FLUSH_SYNC)
1706                 rpc_wait_for_completion_task(task);
1707         rpc_put_task(task);
1708         return 0;
1709 }
1710 EXPORT_SYMBOL_GPL(nfs_initiate_commit);
1711
1712 static loff_t nfs_get_lwb(struct list_head *head)
1713 {
1714         loff_t lwb = 0;
1715         struct nfs_page *req;
1716
1717         list_for_each_entry(req, head, wb_list)
1718                 if (lwb < (req_offset(req) + req->wb_bytes))
1719                         lwb = req_offset(req) + req->wb_bytes;
1720
1721         return lwb;
1722 }
1723
1724 /*
1725  * Set up the argument/result storage required for the RPC call.
1726  */
1727 void nfs_init_commit(struct nfs_commit_data *data,
1728                      struct list_head *head,
1729                      struct pnfs_layout_segment *lseg,
1730                      struct nfs_commit_info *cinfo)
1731 {
1732         struct nfs_page *first;
1733         struct nfs_open_context *ctx;
1734         struct inode *inode;
1735
1736         /* Set up the RPC argument and reply structs
1737          * NB: take care not to mess about with data->commit et al. */
1738
1739         if (head)
1740                 list_splice_init(head, &data->pages);
1741
1742         first = nfs_list_entry(data->pages.next);
1743         ctx = nfs_req_openctx(first);
1744         inode = d_inode(ctx->dentry);
1745
1746         data->inode       = inode;
1747         data->cred        = ctx->cred;
1748         data->lseg        = lseg; /* reference transferred */
1749         /* only set lwb for pnfs commit */
1750         if (lseg)
1751                 data->lwb = nfs_get_lwb(&data->pages);
1752         data->mds_ops     = &nfs_commit_ops;
1753         data->completion_ops = cinfo->completion_ops;
1754         data->dreq        = cinfo->dreq;
1755
1756         data->args.fh     = NFS_FH(data->inode);
1757         /* Note: we always request a commit of the entire inode */
1758         data->args.offset = 0;
1759         data->args.count  = 0;
1760         data->context     = get_nfs_open_context(ctx);
1761         data->res.fattr   = &data->fattr;
1762         data->res.verf    = &data->verf;
1763         nfs_fattr_init(&data->fattr);
1764         nfs_commit_begin(cinfo->mds);
1765 }
1766 EXPORT_SYMBOL_GPL(nfs_init_commit);
1767
1768 void nfs_retry_commit(struct list_head *page_list,
1769                       struct pnfs_layout_segment *lseg,
1770                       struct nfs_commit_info *cinfo,
1771                       u32 ds_commit_idx)
1772 {
1773         struct nfs_page *req;
1774
1775         while (!list_empty(page_list)) {
1776                 req = nfs_list_entry(page_list->next);
1777                 nfs_list_remove_request(req);
1778                 nfs_mark_request_commit(req, lseg, cinfo, ds_commit_idx);
1779                 nfs_folio_clear_commit(nfs_page_to_folio(req));
1780                 nfs_unlock_and_release_request(req);
1781         }
1782 }
1783 EXPORT_SYMBOL_GPL(nfs_retry_commit);
1784
1785 static void nfs_commit_resched_write(struct nfs_commit_info *cinfo,
1786                                      struct nfs_page *req)
1787 {
1788         struct folio *folio = nfs_page_to_folio(req);
1789
1790         filemap_dirty_folio(folio_mapping(folio), folio);
1791 }
1792
1793 /*
1794  * Commit dirty pages
1795  */
1796 static int
1797 nfs_commit_list(struct inode *inode, struct list_head *head, int how,
1798                 struct nfs_commit_info *cinfo)
1799 {
1800         struct nfs_commit_data  *data;
1801         unsigned short task_flags = 0;
1802
1803         /* another commit raced with us */
1804         if (list_empty(head))
1805                 return 0;
1806
1807         data = nfs_commitdata_alloc();
1808         if (!data) {
1809                 nfs_retry_commit(head, NULL, cinfo, -1);
1810                 return -ENOMEM;
1811         }
1812
1813         /* Set up the argument struct */
1814         nfs_init_commit(data, head, NULL, cinfo);
1815         if (NFS_SERVER(inode)->nfs_client->cl_minorversion)
1816                 task_flags = RPC_TASK_MOVEABLE;
1817         return nfs_initiate_commit(NFS_CLIENT(inode), data, NFS_PROTO(inode),
1818                                    data->mds_ops, how,
1819                                    RPC_TASK_CRED_NOREF | task_flags);
1820 }
1821
1822 /*
1823  * COMMIT call returned
1824  */
1825 static void nfs_commit_done(struct rpc_task *task, void *calldata)
1826 {
1827         struct nfs_commit_data  *data = calldata;
1828
1829         /* Call the NFS version-specific code */
1830         NFS_PROTO(data->inode)->commit_done(task, data);
1831         trace_nfs_commit_done(task, data);
1832 }
1833
1834 static void nfs_commit_release_pages(struct nfs_commit_data *data)
1835 {
1836         const struct nfs_writeverf *verf = data->res.verf;
1837         struct nfs_page *req;
1838         int status = data->task.tk_status;
1839         struct nfs_commit_info cinfo;
1840         struct nfs_server *nfss;
1841         struct folio *folio;
1842
1843         while (!list_empty(&data->pages)) {
1844                 req = nfs_list_entry(data->pages.next);
1845                 nfs_list_remove_request(req);
1846                 folio = nfs_page_to_folio(req);
1847                 nfs_folio_clear_commit(folio);
1848
1849                 dprintk("NFS:       commit (%s/%llu %d@%lld)",
1850                         nfs_req_openctx(req)->dentry->d_sb->s_id,
1851                         (unsigned long long)NFS_FILEID(d_inode(nfs_req_openctx(req)->dentry)),
1852                         req->wb_bytes,
1853                         (long long)req_offset(req));
1854                 if (status < 0) {
1855                         if (folio) {
1856                                 trace_nfs_commit_error(data->inode, req,
1857                                                        status);
1858                                 nfs_mapping_set_error(folio, status);
1859                                 nfs_inode_remove_request(req);
1860                         }
1861                         dprintk_cont(", error = %d\n", status);
1862                         goto next;
1863                 }
1864
1865                 /* Okay, COMMIT succeeded, apparently. Check the verifier
1866                  * returned by the server against all stored verfs. */
1867                 if (nfs_write_match_verf(verf, req)) {
1868                         /* We have a match */
1869                         if (folio)
1870                                 nfs_inode_remove_request(req);
1871                         dprintk_cont(" OK\n");
1872                         goto next;
1873                 }
1874                 /* We have a mismatch. Write the page again */
1875                 dprintk_cont(" mismatch\n");
1876                 nfs_mark_request_dirty(req);
1877                 atomic_long_inc(&NFS_I(data->inode)->redirtied_pages);
1878         next:
1879                 nfs_unlock_and_release_request(req);
1880                 /* Latency breaker */
1881                 cond_resched();
1882         }
1883         nfss = NFS_SERVER(data->inode);
1884         if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH)
1885                 nfss->write_congested = 0;
1886
1887         nfs_init_cinfo(&cinfo, data->inode, data->dreq);
1888         nfs_commit_end(cinfo.mds);
1889 }
1890
1891 static void nfs_commit_release(void *calldata)
1892 {
1893         struct nfs_commit_data *data = calldata;
1894
1895         data->completion_ops->completion(data);
1896         nfs_commitdata_release(calldata);
1897 }
1898
1899 static const struct rpc_call_ops nfs_commit_ops = {
1900         .rpc_call_prepare = nfs_commit_prepare,
1901         .rpc_call_done = nfs_commit_done,
1902         .rpc_release = nfs_commit_release,
1903 };
1904
1905 static const struct nfs_commit_completion_ops nfs_commit_completion_ops = {
1906         .completion = nfs_commit_release_pages,
1907         .resched_write = nfs_commit_resched_write,
1908 };
1909
1910 int nfs_generic_commit_list(struct inode *inode, struct list_head *head,
1911                             int how, struct nfs_commit_info *cinfo)
1912 {
1913         int status;
1914
1915         status = pnfs_commit_list(inode, head, how, cinfo);
1916         if (status == PNFS_NOT_ATTEMPTED)
1917                 status = nfs_commit_list(inode, head, how, cinfo);
1918         return status;
1919 }
1920
1921 static int __nfs_commit_inode(struct inode *inode, int how,
1922                 struct writeback_control *wbc)
1923 {
1924         LIST_HEAD(head);
1925         struct nfs_commit_info cinfo;
1926         int may_wait = how & FLUSH_SYNC;
1927         int ret, nscan;
1928
1929         how &= ~FLUSH_SYNC;
1930         nfs_init_cinfo_from_inode(&cinfo, inode);
1931         nfs_commit_begin(cinfo.mds);
1932         for (;;) {
1933                 ret = nscan = nfs_scan_commit(inode, &head, &cinfo);
1934                 if (ret <= 0)
1935                         break;
1936                 ret = nfs_generic_commit_list(inode, &head, how, &cinfo);
1937                 if (ret < 0)
1938                         break;
1939                 ret = 0;
1940                 if (wbc && wbc->sync_mode == WB_SYNC_NONE) {
1941                         if (nscan < wbc->nr_to_write)
1942                                 wbc->nr_to_write -= nscan;
1943                         else
1944                                 wbc->nr_to_write = 0;
1945                 }
1946                 if (nscan < INT_MAX)
1947                         break;
1948                 cond_resched();
1949         }
1950         nfs_commit_end(cinfo.mds);
1951         if (ret || !may_wait)
1952                 return ret;
1953         return wait_on_commit(cinfo.mds);
1954 }
1955
1956 int nfs_commit_inode(struct inode *inode, int how)
1957 {
1958         return __nfs_commit_inode(inode, how, NULL);
1959 }
1960 EXPORT_SYMBOL_GPL(nfs_commit_inode);
1961
1962 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
1963 {
1964         struct nfs_inode *nfsi = NFS_I(inode);
1965         int flags = FLUSH_SYNC;
1966         int ret = 0;
1967
1968         if (wbc->sync_mode == WB_SYNC_NONE) {
1969                 /* no commits means nothing needs to be done */
1970                 if (!atomic_long_read(&nfsi->commit_info.ncommit))
1971                         goto check_requests_outstanding;
1972
1973                 /* Don't commit yet if this is a non-blocking flush and there
1974                  * are a lot of outstanding writes for this mapping.
1975                  */
1976                 if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))
1977                         goto out_mark_dirty;
1978
1979                 /* don't wait for the COMMIT response */
1980                 flags = 0;
1981         }
1982
1983         ret = __nfs_commit_inode(inode, flags, wbc);
1984         if (!ret) {
1985                 if (flags & FLUSH_SYNC)
1986                         return 0;
1987         } else if (atomic_long_read(&nfsi->commit_info.ncommit))
1988                 goto out_mark_dirty;
1989
1990 check_requests_outstanding:
1991         if (!atomic_read(&nfsi->commit_info.rpcs_out))
1992                 return ret;
1993 out_mark_dirty:
1994         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
1995         return ret;
1996 }
1997 EXPORT_SYMBOL_GPL(nfs_write_inode);
1998
1999 /*
2000  * Wrapper for filemap_write_and_wait_range()
2001  *
2002  * Needed for pNFS in order to ensure data becomes visible to the
2003  * client.
2004  */
2005 int nfs_filemap_write_and_wait_range(struct address_space *mapping,
2006                 loff_t lstart, loff_t lend)
2007 {
2008         int ret;
2009
2010         ret = filemap_write_and_wait_range(mapping, lstart, lend);
2011         if (ret == 0)
2012                 ret = pnfs_sync_inode(mapping->host, true);
2013         return ret;
2014 }
2015 EXPORT_SYMBOL_GPL(nfs_filemap_write_and_wait_range);
2016
2017 /*
2018  * flush the inode to disk.
2019  */
2020 int nfs_wb_all(struct inode *inode)
2021 {
2022         int ret;
2023
2024         trace_nfs_writeback_inode_enter(inode);
2025
2026         ret = filemap_write_and_wait(inode->i_mapping);
2027         if (ret)
2028                 goto out;
2029         ret = nfs_commit_inode(inode, FLUSH_SYNC);
2030         if (ret < 0)
2031                 goto out;
2032         pnfs_sync_inode(inode, true);
2033         ret = 0;
2034
2035 out:
2036         trace_nfs_writeback_inode_exit(inode, ret);
2037         return ret;
2038 }
2039 EXPORT_SYMBOL_GPL(nfs_wb_all);
2040
2041 int nfs_wb_folio_cancel(struct inode *inode, struct folio *folio)
2042 {
2043         struct nfs_page *req;
2044         int ret = 0;
2045
2046         folio_wait_writeback(folio);
2047
2048         /* blocking call to cancel all requests and join to a single (head)
2049          * request */
2050         req = nfs_lock_and_join_requests(folio);
2051
2052         if (IS_ERR(req)) {
2053                 ret = PTR_ERR(req);
2054         } else if (req) {
2055                 /* all requests from this folio have been cancelled by
2056                  * nfs_lock_and_join_requests, so just remove the head
2057                  * request from the inode / page_private pointer and
2058                  * release it */
2059                 nfs_inode_remove_request(req);
2060                 nfs_unlock_and_release_request(req);
2061         }
2062
2063         return ret;
2064 }
2065
2066 /**
2067  * nfs_wb_folio - Write back all requests on one page
2068  * @inode: pointer to page
2069  * @folio: pointer to folio
2070  *
2071  * Assumes that the folio has been locked by the caller, and will
2072  * not unlock it.
2073  */
2074 int nfs_wb_folio(struct inode *inode, struct folio *folio)
2075 {
2076         loff_t range_start = folio_file_pos(folio);
2077         loff_t range_end = range_start + (loff_t)folio_size(folio) - 1;
2078         struct writeback_control wbc = {
2079                 .sync_mode = WB_SYNC_ALL,
2080                 .nr_to_write = 0,
2081                 .range_start = range_start,
2082                 .range_end = range_end,
2083         };
2084         int ret;
2085
2086         trace_nfs_writeback_folio(inode, folio);
2087
2088         for (;;) {
2089                 folio_wait_writeback(folio);
2090                 if (folio_clear_dirty_for_io(folio)) {
2091                         ret = nfs_writepage_locked(folio, &wbc);
2092                         if (ret < 0)
2093                                 goto out_error;
2094                         continue;
2095                 }
2096                 ret = 0;
2097                 if (!folio_test_private(folio))
2098                         break;
2099                 ret = nfs_commit_inode(inode, FLUSH_SYNC);
2100                 if (ret < 0)
2101                         goto out_error;
2102         }
2103 out_error:
2104         trace_nfs_writeback_folio_done(inode, folio, ret);
2105         return ret;
2106 }
2107
2108 #ifdef CONFIG_MIGRATION
2109 int nfs_migrate_folio(struct address_space *mapping, struct folio *dst,
2110                 struct folio *src, enum migrate_mode mode)
2111 {
2112         /*
2113          * If the private flag is set, the folio is currently associated with
2114          * an in-progress read or write request. Don't try to migrate it.
2115          *
2116          * FIXME: we could do this in principle, but we'll need a way to ensure
2117          *        that we can safely release the inode reference while holding
2118          *        the folio lock.
2119          */
2120         if (folio_test_private(src))
2121                 return -EBUSY;
2122
2123         if (folio_test_private_2(src)) { /* [DEPRECATED] */
2124                 if (mode == MIGRATE_ASYNC)
2125                         return -EBUSY;
2126                 folio_wait_private_2(src);
2127         }
2128
2129         return migrate_folio(mapping, dst, src, mode);
2130 }
2131 #endif
2132
2133 int __init nfs_init_writepagecache(void)
2134 {
2135         nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
2136                                              sizeof(struct nfs_pgio_header),
2137                                              0, SLAB_HWCACHE_ALIGN,
2138                                              NULL);
2139         if (nfs_wdata_cachep == NULL)
2140                 return -ENOMEM;
2141
2142         nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE,
2143                                                      nfs_wdata_cachep);
2144         if (nfs_wdata_mempool == NULL)
2145                 goto out_destroy_write_cache;
2146
2147         nfs_cdata_cachep = kmem_cache_create("nfs_commit_data",
2148                                              sizeof(struct nfs_commit_data),
2149                                              0, SLAB_HWCACHE_ALIGN,
2150                                              NULL);
2151         if (nfs_cdata_cachep == NULL)
2152                 goto out_destroy_write_mempool;
2153
2154         nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT,
2155                                                       nfs_cdata_cachep);
2156         if (nfs_commit_mempool == NULL)
2157                 goto out_destroy_commit_cache;
2158
2159         /*
2160          * NFS congestion size, scale with available memory.
2161          *
2162          *  64MB:    8192k
2163          * 128MB:   11585k
2164          * 256MB:   16384k
2165          * 512MB:   23170k
2166          *   1GB:   32768k
2167          *   2GB:   46340k
2168          *   4GB:   65536k
2169          *   8GB:   92681k
2170          *  16GB:  131072k
2171          *
2172          * This allows larger machines to have larger/more transfers.
2173          * Limit the default to 256M
2174          */
2175         nfs_congestion_kb = (16*int_sqrt(totalram_pages())) << (PAGE_SHIFT-10);
2176         if (nfs_congestion_kb > 256*1024)
2177                 nfs_congestion_kb = 256*1024;
2178
2179         return 0;
2180
2181 out_destroy_commit_cache:
2182         kmem_cache_destroy(nfs_cdata_cachep);
2183 out_destroy_write_mempool:
2184         mempool_destroy(nfs_wdata_mempool);
2185 out_destroy_write_cache:
2186         kmem_cache_destroy(nfs_wdata_cachep);
2187         return -ENOMEM;
2188 }
2189
2190 void nfs_destroy_writepagecache(void)
2191 {
2192         mempool_destroy(nfs_commit_mempool);
2193         kmem_cache_destroy(nfs_cdata_cachep);
2194         mempool_destroy(nfs_wdata_mempool);
2195         kmem_cache_destroy(nfs_wdata_cachep);
2196 }
2197
2198 static const struct nfs_rw_ops nfs_rw_write_ops = {
2199         .rw_alloc_header        = nfs_writehdr_alloc,
2200         .rw_free_header         = nfs_writehdr_free,
2201         .rw_done                = nfs_writeback_done,
2202         .rw_result              = nfs_writeback_result,
2203         .rw_initiate            = nfs_initiate_write,
2204 };