1 /* 2 * linux/fs/nfs/write.c 3 * 4 * Write file data over NFS. 5 * 6 * Copyright (C) 1996, 1997, Olaf Kirch <okir@monad.swb.de> 7 */ 8 9 #include <linux/types.h> 10 #include <linux/slab.h> 11 #include <linux/mm.h> 12 #include <linux/pagemap.h> 13 #include <linux/file.h> 14 #include <linux/writeback.h> 15 #include <linux/swap.h> 16 #include <linux/migrate.h> 17 18 #include <linux/sunrpc/clnt.h> 19 #include <linux/nfs_fs.h> 20 #include <linux/nfs_mount.h> 21 #include <linux/nfs_page.h> 22 #include <linux/backing-dev.h> 23 #include <linux/export.h> 24 25 #include <asm/uaccess.h> 26 27 #include "delegation.h" 28 #include "internal.h" 29 #include "iostat.h" 30 #include "nfs4_fs.h" 31 #include "fscache.h" 32 #include "pnfs.h" 33 34 #include "nfstrace.h" 35 36 #define NFSDBG_FACILITY NFSDBG_PAGECACHE 37 38 #define MIN_POOL_WRITE (32) 39 #define MIN_POOL_COMMIT (4) 40 41 /* 42 * Local function declarations 43 */ 44 static void nfs_redirty_request(struct nfs_page *req); 45 static const struct rpc_call_ops nfs_commit_ops; 46 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops; 47 static const struct nfs_commit_completion_ops nfs_commit_completion_ops; 48 static const struct nfs_rw_ops nfs_rw_write_ops; 49 static void nfs_clear_request_commit(struct nfs_page *req); 50 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo, 51 struct inode *inode); 52 static struct nfs_page * 53 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi, 54 struct page *page); 55 56 static struct kmem_cache *nfs_wdata_cachep; 57 static mempool_t *nfs_wdata_mempool; 58 static struct kmem_cache *nfs_cdata_cachep; 59 static mempool_t *nfs_commit_mempool; 60 61 struct nfs_commit_data *nfs_commitdata_alloc(void) 62 { 63 struct nfs_commit_data *p = mempool_alloc(nfs_commit_mempool, GFP_NOIO); 64 65 if (p) { 66 memset(p, 0, sizeof(*p)); 67 INIT_LIST_HEAD(&p->pages); 68 } 69 return p; 70 } 71 EXPORT_SYMBOL_GPL(nfs_commitdata_alloc); 72 73 void nfs_commit_free(struct nfs_commit_data *p) 74 { 75 mempool_free(p, nfs_commit_mempool); 76 } 77 EXPORT_SYMBOL_GPL(nfs_commit_free); 78 79 static struct nfs_pgio_header *nfs_writehdr_alloc(void) 80 { 81 struct nfs_pgio_header *p = mempool_alloc(nfs_wdata_mempool, GFP_NOIO); 82 83 if (p) 84 memset(p, 0, sizeof(*p)); 85 return p; 86 } 87 88 static void nfs_writehdr_free(struct nfs_pgio_header *hdr) 89 { 90 mempool_free(hdr, nfs_wdata_mempool); 91 } 92 93 static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error) 94 { 95 ctx->error = error; 96 smp_wmb(); 97 set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags); 98 } 99 100 /* 101 * nfs_page_find_head_request_locked - find head request associated with @page 102 * 103 * must be called while holding the inode lock. 104 * 105 * returns matching head request with reference held, or NULL if not found. 106 */ 107 static struct nfs_page * 108 nfs_page_find_head_request_locked(struct nfs_inode *nfsi, struct page *page) 109 { 110 struct nfs_page *req = NULL; 111 112 if (PagePrivate(page)) 113 req = (struct nfs_page *)page_private(page); 114 else if (unlikely(PageSwapCache(page))) 115 req = nfs_page_search_commits_for_head_request_locked(nfsi, 116 page); 117 118 if (req) { 119 WARN_ON_ONCE(req->wb_head != req); 120 kref_get(&req->wb_kref); 121 } 122 123 return req; 124 } 125 126 /* 127 * nfs_page_find_head_request - find head request associated with @page 128 * 129 * returns matching head request with reference held, or NULL if not found. 130 */ 131 static struct nfs_page *nfs_page_find_head_request(struct page *page) 132 { 133 struct inode *inode = page_file_mapping(page)->host; 134 struct nfs_page *req = NULL; 135 136 spin_lock(&inode->i_lock); 137 req = nfs_page_find_head_request_locked(NFS_I(inode), page); 138 spin_unlock(&inode->i_lock); 139 return req; 140 } 141 142 /* Adjust the file length if we're writing beyond the end */ 143 static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count) 144 { 145 struct inode *inode = page_file_mapping(page)->host; 146 loff_t end, i_size; 147 pgoff_t end_index; 148 149 spin_lock(&inode->i_lock); 150 i_size = i_size_read(inode); 151 end_index = (i_size - 1) >> PAGE_CACHE_SHIFT; 152 if (i_size > 0 && page_file_index(page) < end_index) 153 goto out; 154 end = page_file_offset(page) + ((loff_t)offset+count); 155 if (i_size >= end) 156 goto out; 157 i_size_write(inode, end); 158 nfs_inc_stats(inode, NFSIOS_EXTENDWRITE); 159 out: 160 spin_unlock(&inode->i_lock); 161 } 162 163 /* A writeback failed: mark the page as bad, and invalidate the page cache */ 164 static void nfs_set_pageerror(struct page *page) 165 { 166 nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page)); 167 } 168 169 /* 170 * nfs_page_group_search_locked 171 * @head - head request of page group 172 * @page_offset - offset into page 173 * 174 * Search page group with head @head to find a request that contains the 175 * page offset @page_offset. 176 * 177 * Returns a pointer to the first matching nfs request, or NULL if no 178 * match is found. 179 * 180 * Must be called with the page group lock held 181 */ 182 static struct nfs_page * 183 nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset) 184 { 185 struct nfs_page *req; 186 187 WARN_ON_ONCE(head != head->wb_head); 188 WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_head->wb_flags)); 189 190 req = head; 191 do { 192 if (page_offset >= req->wb_pgbase && 193 page_offset < (req->wb_pgbase + req->wb_bytes)) 194 return req; 195 196 req = req->wb_this_page; 197 } while (req != head); 198 199 return NULL; 200 } 201 202 /* 203 * nfs_page_group_covers_page 204 * @head - head request of page group 205 * 206 * Return true if the page group with head @head covers the whole page, 207 * returns false otherwise 208 */ 209 static bool nfs_page_group_covers_page(struct nfs_page *req) 210 { 211 struct nfs_page *tmp; 212 unsigned int pos = 0; 213 unsigned int len = nfs_page_length(req->wb_page); 214 215 nfs_page_group_lock(req, false); 216 217 do { 218 tmp = nfs_page_group_search_locked(req->wb_head, pos); 219 if (tmp) { 220 /* no way this should happen */ 221 WARN_ON_ONCE(tmp->wb_pgbase != pos); 222 pos += tmp->wb_bytes - (pos - tmp->wb_pgbase); 223 } 224 } while (tmp && pos < len); 225 226 nfs_page_group_unlock(req); 227 WARN_ON_ONCE(pos > len); 228 return pos == len; 229 } 230 231 /* We can set the PG_uptodate flag if we see that a write request 232 * covers the full page. 233 */ 234 static void nfs_mark_uptodate(struct nfs_page *req) 235 { 236 if (PageUptodate(req->wb_page)) 237 return; 238 if (!nfs_page_group_covers_page(req)) 239 return; 240 SetPageUptodate(req->wb_page); 241 } 242 243 static int wb_priority(struct writeback_control *wbc) 244 { 245 int ret = 0; 246 if (wbc->for_reclaim) 247 return FLUSH_HIGHPRI | FLUSH_STABLE; 248 if (wbc->sync_mode == WB_SYNC_ALL) 249 ret = FLUSH_COND_STABLE; 250 if (wbc->for_kupdate || wbc->for_background) 251 ret |= FLUSH_LOWPRI; 252 return ret; 253 } 254 255 /* 256 * NFS congestion control 257 */ 258 259 int nfs_congestion_kb; 260 261 #define NFS_CONGESTION_ON_THRESH (nfs_congestion_kb >> (PAGE_SHIFT-10)) 262 #define NFS_CONGESTION_OFF_THRESH \ 263 (NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2)) 264 265 static void nfs_set_page_writeback(struct page *page) 266 { 267 struct nfs_server *nfss = NFS_SERVER(page_file_mapping(page)->host); 268 int ret = test_set_page_writeback(page); 269 270 WARN_ON_ONCE(ret != 0); 271 272 if (atomic_long_inc_return(&nfss->writeback) > 273 NFS_CONGESTION_ON_THRESH) { 274 set_bdi_congested(&nfss->backing_dev_info, 275 BLK_RW_ASYNC); 276 } 277 } 278 279 static void nfs_end_page_writeback(struct nfs_page *req) 280 { 281 struct inode *inode = page_file_mapping(req->wb_page)->host; 282 struct nfs_server *nfss = NFS_SERVER(inode); 283 284 if (!nfs_page_group_sync_on_bit(req, PG_WB_END)) 285 return; 286 287 end_page_writeback(req->wb_page); 288 if (atomic_long_dec_return(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) 289 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC); 290 } 291 292 293 /* nfs_page_group_clear_bits 294 * @req - an nfs request 295 * clears all page group related bits from @req 296 */ 297 static void 298 nfs_page_group_clear_bits(struct nfs_page *req) 299 { 300 clear_bit(PG_TEARDOWN, &req->wb_flags); 301 clear_bit(PG_UNLOCKPAGE, &req->wb_flags); 302 clear_bit(PG_UPTODATE, &req->wb_flags); 303 clear_bit(PG_WB_END, &req->wb_flags); 304 clear_bit(PG_REMOVE, &req->wb_flags); 305 } 306 307 308 /* 309 * nfs_unroll_locks_and_wait - unlock all newly locked reqs and wait on @req 310 * 311 * this is a helper function for nfs_lock_and_join_requests 312 * 313 * @inode - inode associated with request page group, must be holding inode lock 314 * @head - head request of page group, must be holding head lock 315 * @req - request that couldn't lock and needs to wait on the req bit lock 316 * @nonblock - if true, don't actually wait 317 * 318 * NOTE: this must be called holding page_group bit lock and inode spin lock 319 * and BOTH will be released before returning. 320 * 321 * returns 0 on success, < 0 on error. 322 */ 323 static int 324 nfs_unroll_locks_and_wait(struct inode *inode, struct nfs_page *head, 325 struct nfs_page *req, bool nonblock) 326 __releases(&inode->i_lock) 327 { 328 struct nfs_page *tmp; 329 int ret; 330 331 /* relinquish all the locks successfully grabbed this run */ 332 for (tmp = head ; tmp != req; tmp = tmp->wb_this_page) 333 nfs_unlock_request(tmp); 334 335 WARN_ON_ONCE(test_bit(PG_TEARDOWN, &req->wb_flags)); 336 337 /* grab a ref on the request that will be waited on */ 338 kref_get(&req->wb_kref); 339 340 nfs_page_group_unlock(head); 341 spin_unlock(&inode->i_lock); 342 343 /* release ref from nfs_page_find_head_request_locked */ 344 nfs_release_request(head); 345 346 if (!nonblock) 347 ret = nfs_wait_on_request(req); 348 else 349 ret = -EAGAIN; 350 nfs_release_request(req); 351 352 return ret; 353 } 354 355 /* 356 * nfs_destroy_unlinked_subrequests - destroy recently unlinked subrequests 357 * 358 * @destroy_list - request list (using wb_this_page) terminated by @old_head 359 * @old_head - the old head of the list 360 * 361 * All subrequests must be locked and removed from all lists, so at this point 362 * they are only "active" in this function, and possibly in nfs_wait_on_request 363 * with a reference held by some other context. 364 */ 365 static void 366 nfs_destroy_unlinked_subrequests(struct nfs_page *destroy_list, 367 struct nfs_page *old_head) 368 { 369 while (destroy_list) { 370 struct nfs_page *subreq = destroy_list; 371 372 destroy_list = (subreq->wb_this_page == old_head) ? 373 NULL : subreq->wb_this_page; 374 375 WARN_ON_ONCE(old_head != subreq->wb_head); 376 377 /* make sure old group is not used */ 378 subreq->wb_head = subreq; 379 subreq->wb_this_page = subreq; 380 381 /* subreq is now totally disconnected from page group or any 382 * write / commit lists. last chance to wake any waiters */ 383 nfs_unlock_request(subreq); 384 385 if (!test_bit(PG_TEARDOWN, &subreq->wb_flags)) { 386 /* release ref on old head request */ 387 nfs_release_request(old_head); 388 389 nfs_page_group_clear_bits(subreq); 390 391 /* release the PG_INODE_REF reference */ 392 if (test_and_clear_bit(PG_INODE_REF, &subreq->wb_flags)) 393 nfs_release_request(subreq); 394 else 395 WARN_ON_ONCE(1); 396 } else { 397 WARN_ON_ONCE(test_bit(PG_CLEAN, &subreq->wb_flags)); 398 /* zombie requests have already released the last 399 * reference and were waiting on the rest of the 400 * group to complete. Since it's no longer part of a 401 * group, simply free the request */ 402 nfs_page_group_clear_bits(subreq); 403 nfs_free_request(subreq); 404 } 405 } 406 } 407 408 /* 409 * nfs_lock_and_join_requests - join all subreqs to the head req and return 410 * a locked reference, cancelling any pending 411 * operations for this page. 412 * 413 * @page - the page used to lookup the "page group" of nfs_page structures 414 * @nonblock - if true, don't block waiting for request locks 415 * 416 * This function joins all sub requests to the head request by first 417 * locking all requests in the group, cancelling any pending operations 418 * and finally updating the head request to cover the whole range covered by 419 * the (former) group. All subrequests are removed from any write or commit 420 * lists, unlinked from the group and destroyed. 421 * 422 * Returns a locked, referenced pointer to the head request - which after 423 * this call is guaranteed to be the only request associated with the page. 424 * Returns NULL if no requests are found for @page, or a ERR_PTR if an 425 * error was encountered. 426 */ 427 static struct nfs_page * 428 nfs_lock_and_join_requests(struct page *page, bool nonblock) 429 { 430 struct inode *inode = page_file_mapping(page)->host; 431 struct nfs_page *head, *subreq; 432 struct nfs_page *destroy_list = NULL; 433 unsigned int total_bytes; 434 int ret; 435 436 try_again: 437 total_bytes = 0; 438 439 WARN_ON_ONCE(destroy_list); 440 441 spin_lock(&inode->i_lock); 442 443 /* 444 * A reference is taken only on the head request which acts as a 445 * reference to the whole page group - the group will not be destroyed 446 * until the head reference is released. 447 */ 448 head = nfs_page_find_head_request_locked(NFS_I(inode), page); 449 450 if (!head) { 451 spin_unlock(&inode->i_lock); 452 return NULL; 453 } 454 455 /* holding inode lock, so always make a non-blocking call to try the 456 * page group lock */ 457 ret = nfs_page_group_lock(head, true); 458 if (ret < 0) { 459 spin_unlock(&inode->i_lock); 460 461 if (!nonblock && ret == -EAGAIN) { 462 nfs_page_group_lock_wait(head); 463 nfs_release_request(head); 464 goto try_again; 465 } 466 467 nfs_release_request(head); 468 return ERR_PTR(ret); 469 } 470 471 /* lock each request in the page group */ 472 subreq = head; 473 do { 474 /* 475 * Subrequests are always contiguous, non overlapping 476 * and in order. If not, it's a programming error. 477 */ 478 WARN_ON_ONCE(subreq->wb_offset != 479 (head->wb_offset + total_bytes)); 480 481 /* keep track of how many bytes this group covers */ 482 total_bytes += subreq->wb_bytes; 483 484 if (!nfs_lock_request(subreq)) { 485 /* releases page group bit lock and 486 * inode spin lock and all references */ 487 ret = nfs_unroll_locks_and_wait(inode, head, 488 subreq, nonblock); 489 490 if (ret == 0) 491 goto try_again; 492 493 return ERR_PTR(ret); 494 } 495 496 subreq = subreq->wb_this_page; 497 } while (subreq != head); 498 499 /* Now that all requests are locked, make sure they aren't on any list. 500 * Commit list removal accounting is done after locks are dropped */ 501 subreq = head; 502 do { 503 nfs_clear_request_commit(subreq); 504 subreq = subreq->wb_this_page; 505 } while (subreq != head); 506 507 /* unlink subrequests from head, destroy them later */ 508 if (head->wb_this_page != head) { 509 /* destroy list will be terminated by head */ 510 destroy_list = head->wb_this_page; 511 head->wb_this_page = head; 512 513 /* change head request to cover whole range that 514 * the former page group covered */ 515 head->wb_bytes = total_bytes; 516 } 517 518 /* 519 * prepare head request to be added to new pgio descriptor 520 */ 521 nfs_page_group_clear_bits(head); 522 523 /* 524 * some part of the group was still on the inode list - otherwise 525 * the group wouldn't be involved in async write. 526 * grab a reference for the head request, iff it needs one. 527 */ 528 if (!test_and_set_bit(PG_INODE_REF, &head->wb_flags)) 529 kref_get(&head->wb_kref); 530 531 nfs_page_group_unlock(head); 532 533 /* drop lock to clean uprequests on destroy list */ 534 spin_unlock(&inode->i_lock); 535 536 nfs_destroy_unlinked_subrequests(destroy_list, head); 537 538 /* still holds ref on head from nfs_page_find_head_request_locked 539 * and still has lock on head from lock loop */ 540 return head; 541 } 542 543 /* 544 * Find an associated nfs write request, and prepare to flush it out 545 * May return an error if the user signalled nfs_wait_on_request(). 546 */ 547 static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio, 548 struct page *page, bool nonblock) 549 { 550 struct nfs_page *req; 551 int ret = 0; 552 553 req = nfs_lock_and_join_requests(page, nonblock); 554 if (!req) 555 goto out; 556 ret = PTR_ERR(req); 557 if (IS_ERR(req)) 558 goto out; 559 560 nfs_set_page_writeback(page); 561 WARN_ON_ONCE(test_bit(PG_CLEAN, &req->wb_flags)); 562 563 ret = 0; 564 if (!nfs_pageio_add_request(pgio, req)) { 565 nfs_redirty_request(req); 566 ret = pgio->pg_error; 567 } 568 out: 569 return ret; 570 } 571 572 static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio) 573 { 574 struct inode *inode = page_file_mapping(page)->host; 575 int ret; 576 577 nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGE); 578 nfs_add_stats(inode, NFSIOS_WRITEPAGES, 1); 579 580 nfs_pageio_cond_complete(pgio, page_file_index(page)); 581 ret = nfs_page_async_flush(pgio, page, wbc->sync_mode == WB_SYNC_NONE); 582 if (ret == -EAGAIN) { 583 redirty_page_for_writepage(wbc, page); 584 ret = 0; 585 } 586 return ret; 587 } 588 589 /* 590 * Write an mmapped page to the server. 591 */ 592 static int nfs_writepage_locked(struct page *page, struct writeback_control *wbc) 593 { 594 struct nfs_pageio_descriptor pgio; 595 int err; 596 597 nfs_pageio_init_write(&pgio, page->mapping->host, wb_priority(wbc), 598 false, &nfs_async_write_completion_ops); 599 err = nfs_do_writepage(page, wbc, &pgio); 600 nfs_pageio_complete(&pgio); 601 if (err < 0) 602 return err; 603 if (pgio.pg_error < 0) 604 return pgio.pg_error; 605 return 0; 606 } 607 608 int nfs_writepage(struct page *page, struct writeback_control *wbc) 609 { 610 int ret; 611 612 ret = nfs_writepage_locked(page, wbc); 613 unlock_page(page); 614 return ret; 615 } 616 617 static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data) 618 { 619 int ret; 620 621 ret = nfs_do_writepage(page, wbc, data); 622 unlock_page(page); 623 return ret; 624 } 625 626 int nfs_writepages(struct address_space *mapping, struct writeback_control *wbc) 627 { 628 struct inode *inode = mapping->host; 629 unsigned long *bitlock = &NFS_I(inode)->flags; 630 struct nfs_pageio_descriptor pgio; 631 int err; 632 633 /* Stop dirtying of new pages while we sync */ 634 err = wait_on_bit_lock_action(bitlock, NFS_INO_FLUSHING, 635 nfs_wait_bit_killable, TASK_KILLABLE); 636 if (err) 637 goto out_err; 638 639 nfs_inc_stats(inode, NFSIOS_VFSWRITEPAGES); 640 641 nfs_pageio_init_write(&pgio, inode, wb_priority(wbc), false, 642 &nfs_async_write_completion_ops); 643 err = write_cache_pages(mapping, wbc, nfs_writepages_callback, &pgio); 644 nfs_pageio_complete(&pgio); 645 646 clear_bit_unlock(NFS_INO_FLUSHING, bitlock); 647 smp_mb__after_atomic(); 648 wake_up_bit(bitlock, NFS_INO_FLUSHING); 649 650 if (err < 0) 651 goto out_err; 652 err = pgio.pg_error; 653 if (err < 0) 654 goto out_err; 655 return 0; 656 out_err: 657 return err; 658 } 659 660 /* 661 * Insert a write request into an inode 662 */ 663 static void nfs_inode_add_request(struct inode *inode, struct nfs_page *req) 664 { 665 struct nfs_inode *nfsi = NFS_I(inode); 666 667 WARN_ON_ONCE(req->wb_this_page != req); 668 669 /* Lock the request! */ 670 nfs_lock_request(req); 671 672 spin_lock(&inode->i_lock); 673 if (!nfsi->npages && NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) 674 inode->i_version++; 675 /* 676 * Swap-space should not get truncated. Hence no need to plug the race 677 * with invalidate/truncate. 678 */ 679 if (likely(!PageSwapCache(req->wb_page))) { 680 set_bit(PG_MAPPED, &req->wb_flags); 681 SetPagePrivate(req->wb_page); 682 set_page_private(req->wb_page, (unsigned long)req); 683 } 684 nfsi->npages++; 685 /* this a head request for a page group - mark it as having an 686 * extra reference so sub groups can follow suit */ 687 WARN_ON(test_and_set_bit(PG_INODE_REF, &req->wb_flags)); 688 kref_get(&req->wb_kref); 689 spin_unlock(&inode->i_lock); 690 } 691 692 /* 693 * Remove a write request from an inode 694 */ 695 static void nfs_inode_remove_request(struct nfs_page *req) 696 { 697 struct inode *inode = req->wb_context->dentry->d_inode; 698 struct nfs_inode *nfsi = NFS_I(inode); 699 struct nfs_page *head; 700 701 if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) { 702 head = req->wb_head; 703 704 spin_lock(&inode->i_lock); 705 if (likely(!PageSwapCache(head->wb_page))) { 706 set_page_private(head->wb_page, 0); 707 ClearPagePrivate(head->wb_page); 708 smp_mb__after_atomic(); 709 wake_up_page(head->wb_page, PG_private); 710 clear_bit(PG_MAPPED, &head->wb_flags); 711 } 712 nfsi->npages--; 713 spin_unlock(&inode->i_lock); 714 } 715 716 if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) 717 nfs_release_request(req); 718 } 719 720 static void 721 nfs_mark_request_dirty(struct nfs_page *req) 722 { 723 __set_page_dirty_nobuffers(req->wb_page); 724 } 725 726 /* 727 * nfs_page_search_commits_for_head_request_locked 728 * 729 * Search through commit lists on @inode for the head request for @page. 730 * Must be called while holding the inode (which is cinfo) lock. 731 * 732 * Returns the head request if found, or NULL if not found. 733 */ 734 static struct nfs_page * 735 nfs_page_search_commits_for_head_request_locked(struct nfs_inode *nfsi, 736 struct page *page) 737 { 738 struct nfs_page *freq, *t; 739 struct nfs_commit_info cinfo; 740 struct inode *inode = &nfsi->vfs_inode; 741 742 nfs_init_cinfo_from_inode(&cinfo, inode); 743 744 /* search through pnfs commit lists */ 745 freq = pnfs_search_commit_reqs(inode, &cinfo, page); 746 if (freq) 747 return freq->wb_head; 748 749 /* Linearly search the commit list for the correct request */ 750 list_for_each_entry_safe(freq, t, &cinfo.mds->list, wb_list) { 751 if (freq->wb_page == page) 752 return freq->wb_head; 753 } 754 755 return NULL; 756 } 757 758 /** 759 * nfs_request_add_commit_list - add request to a commit list 760 * @req: pointer to a struct nfs_page 761 * @dst: commit list head 762 * @cinfo: holds list lock and accounting info 763 * 764 * This sets the PG_CLEAN bit, updates the cinfo count of 765 * number of outstanding requests requiring a commit as well as 766 * the MM page stats. 767 * 768 * The caller must _not_ hold the cinfo->lock, but must be 769 * holding the nfs_page lock. 770 */ 771 void 772 nfs_request_add_commit_list(struct nfs_page *req, struct list_head *dst, 773 struct nfs_commit_info *cinfo) 774 { 775 set_bit(PG_CLEAN, &(req)->wb_flags); 776 spin_lock(cinfo->lock); 777 nfs_list_add_request(req, dst); 778 cinfo->mds->ncommit++; 779 spin_unlock(cinfo->lock); 780 if (!cinfo->dreq) { 781 inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); 782 inc_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info, 783 BDI_RECLAIMABLE); 784 __mark_inode_dirty(req->wb_context->dentry->d_inode, 785 I_DIRTY_DATASYNC); 786 } 787 } 788 EXPORT_SYMBOL_GPL(nfs_request_add_commit_list); 789 790 /** 791 * nfs_request_remove_commit_list - Remove request from a commit list 792 * @req: pointer to a nfs_page 793 * @cinfo: holds list lock and accounting info 794 * 795 * This clears the PG_CLEAN bit, and updates the cinfo's count of 796 * number of outstanding requests requiring a commit 797 * It does not update the MM page stats. 798 * 799 * The caller _must_ hold the cinfo->lock and the nfs_page lock. 800 */ 801 void 802 nfs_request_remove_commit_list(struct nfs_page *req, 803 struct nfs_commit_info *cinfo) 804 { 805 if (!test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) 806 return; 807 nfs_list_remove_request(req); 808 cinfo->mds->ncommit--; 809 } 810 EXPORT_SYMBOL_GPL(nfs_request_remove_commit_list); 811 812 static void nfs_init_cinfo_from_inode(struct nfs_commit_info *cinfo, 813 struct inode *inode) 814 { 815 cinfo->lock = &inode->i_lock; 816 cinfo->mds = &NFS_I(inode)->commit_info; 817 cinfo->ds = pnfs_get_ds_info(inode); 818 cinfo->dreq = NULL; 819 cinfo->completion_ops = &nfs_commit_completion_ops; 820 } 821 822 void nfs_init_cinfo(struct nfs_commit_info *cinfo, 823 struct inode *inode, 824 struct nfs_direct_req *dreq) 825 { 826 if (dreq) 827 nfs_init_cinfo_from_dreq(cinfo, dreq); 828 else 829 nfs_init_cinfo_from_inode(cinfo, inode); 830 } 831 EXPORT_SYMBOL_GPL(nfs_init_cinfo); 832 833 /* 834 * Add a request to the inode's commit list. 835 */ 836 void 837 nfs_mark_request_commit(struct nfs_page *req, struct pnfs_layout_segment *lseg, 838 struct nfs_commit_info *cinfo) 839 { 840 if (pnfs_mark_request_commit(req, lseg, cinfo)) 841 return; 842 nfs_request_add_commit_list(req, &cinfo->mds->list, cinfo); 843 } 844 845 static void 846 nfs_clear_page_commit(struct page *page) 847 { 848 dec_zone_page_state(page, NR_UNSTABLE_NFS); 849 dec_bdi_stat(page_file_mapping(page)->backing_dev_info, BDI_RECLAIMABLE); 850 } 851 852 /* Called holding inode (/cinfo) lock */ 853 static void 854 nfs_clear_request_commit(struct nfs_page *req) 855 { 856 if (test_bit(PG_CLEAN, &req->wb_flags)) { 857 struct inode *inode = req->wb_context->dentry->d_inode; 858 struct nfs_commit_info cinfo; 859 860 nfs_init_cinfo_from_inode(&cinfo, inode); 861 if (!pnfs_clear_request_commit(req, &cinfo)) { 862 nfs_request_remove_commit_list(req, &cinfo); 863 } 864 nfs_clear_page_commit(req->wb_page); 865 } 866 } 867 868 int nfs_write_need_commit(struct nfs_pgio_header *hdr) 869 { 870 if (hdr->verf.committed == NFS_DATA_SYNC) 871 return hdr->lseg == NULL; 872 return hdr->verf.committed != NFS_FILE_SYNC; 873 } 874 875 static void nfs_write_completion(struct nfs_pgio_header *hdr) 876 { 877 struct nfs_commit_info cinfo; 878 unsigned long bytes = 0; 879 880 if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) 881 goto out; 882 nfs_init_cinfo_from_inode(&cinfo, hdr->inode); 883 while (!list_empty(&hdr->pages)) { 884 struct nfs_page *req = nfs_list_entry(hdr->pages.next); 885 886 bytes += req->wb_bytes; 887 nfs_list_remove_request(req); 888 if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && 889 (hdr->good_bytes < bytes)) { 890 nfs_set_pageerror(req->wb_page); 891 nfs_context_set_write_error(req->wb_context, hdr->error); 892 goto remove_req; 893 } 894 if (nfs_write_need_commit(hdr)) { 895 memcpy(&req->wb_verf, &hdr->verf.verifier, sizeof(req->wb_verf)); 896 nfs_mark_request_commit(req, hdr->lseg, &cinfo); 897 goto next; 898 } 899 remove_req: 900 nfs_inode_remove_request(req); 901 next: 902 nfs_unlock_request(req); 903 nfs_end_page_writeback(req); 904 nfs_release_request(req); 905 } 906 out: 907 hdr->release(hdr); 908 } 909 910 unsigned long 911 nfs_reqs_to_commit(struct nfs_commit_info *cinfo) 912 { 913 return cinfo->mds->ncommit; 914 } 915 916 /* cinfo->lock held by caller */ 917 int 918 nfs_scan_commit_list(struct list_head *src, struct list_head *dst, 919 struct nfs_commit_info *cinfo, int max) 920 { 921 struct nfs_page *req, *tmp; 922 int ret = 0; 923 924 list_for_each_entry_safe(req, tmp, src, wb_list) { 925 if (!nfs_lock_request(req)) 926 continue; 927 kref_get(&req->wb_kref); 928 if (cond_resched_lock(cinfo->lock)) 929 list_safe_reset_next(req, tmp, wb_list); 930 nfs_request_remove_commit_list(req, cinfo); 931 nfs_list_add_request(req, dst); 932 ret++; 933 if ((ret == max) && !cinfo->dreq) 934 break; 935 } 936 return ret; 937 } 938 939 /* 940 * nfs_scan_commit - Scan an inode for commit requests 941 * @inode: NFS inode to scan 942 * @dst: mds destination list 943 * @cinfo: mds and ds lists of reqs ready to commit 944 * 945 * Moves requests from the inode's 'commit' request list. 946 * The requests are *not* checked to ensure that they form a contiguous set. 947 */ 948 int 949 nfs_scan_commit(struct inode *inode, struct list_head *dst, 950 struct nfs_commit_info *cinfo) 951 { 952 int ret = 0; 953 954 spin_lock(cinfo->lock); 955 if (cinfo->mds->ncommit > 0) { 956 const int max = INT_MAX; 957 958 ret = nfs_scan_commit_list(&cinfo->mds->list, dst, 959 cinfo, max); 960 ret += pnfs_scan_commit_lists(inode, cinfo, max - ret); 961 } 962 spin_unlock(cinfo->lock); 963 return ret; 964 } 965 966 /* 967 * Search for an existing write request, and attempt to update 968 * it to reflect a new dirty region on a given page. 969 * 970 * If the attempt fails, then the existing request is flushed out 971 * to disk. 972 */ 973 static struct nfs_page *nfs_try_to_update_request(struct inode *inode, 974 struct page *page, 975 unsigned int offset, 976 unsigned int bytes) 977 { 978 struct nfs_page *req; 979 unsigned int rqend; 980 unsigned int end; 981 int error; 982 983 if (!PagePrivate(page)) 984 return NULL; 985 986 end = offset + bytes; 987 spin_lock(&inode->i_lock); 988 989 for (;;) { 990 req = nfs_page_find_head_request_locked(NFS_I(inode), page); 991 if (req == NULL) 992 goto out_unlock; 993 994 /* should be handled by nfs_flush_incompatible */ 995 WARN_ON_ONCE(req->wb_head != req); 996 WARN_ON_ONCE(req->wb_this_page != req); 997 998 rqend = req->wb_offset + req->wb_bytes; 999 /* 1000 * Tell the caller to flush out the request if 1001 * the offsets are non-contiguous. 1002 * Note: nfs_flush_incompatible() will already 1003 * have flushed out requests having wrong owners. 1004 */ 1005 if (offset > rqend 1006 || end < req->wb_offset) 1007 goto out_flushme; 1008 1009 if (nfs_lock_request(req)) 1010 break; 1011 1012 /* The request is locked, so wait and then retry */ 1013 spin_unlock(&inode->i_lock); 1014 error = nfs_wait_on_request(req); 1015 nfs_release_request(req); 1016 if (error != 0) 1017 goto out_err; 1018 spin_lock(&inode->i_lock); 1019 } 1020 1021 /* Okay, the request matches. Update the region */ 1022 if (offset < req->wb_offset) { 1023 req->wb_offset = offset; 1024 req->wb_pgbase = offset; 1025 } 1026 if (end > rqend) 1027 req->wb_bytes = end - req->wb_offset; 1028 else 1029 req->wb_bytes = rqend - req->wb_offset; 1030 out_unlock: 1031 if (req) 1032 nfs_clear_request_commit(req); 1033 spin_unlock(&inode->i_lock); 1034 return req; 1035 out_flushme: 1036 spin_unlock(&inode->i_lock); 1037 nfs_release_request(req); 1038 error = nfs_wb_page(inode, page); 1039 out_err: 1040 return ERR_PTR(error); 1041 } 1042 1043 /* 1044 * Try to update an existing write request, or create one if there is none. 1045 * 1046 * Note: Should always be called with the Page Lock held to prevent races 1047 * if we have to add a new request. Also assumes that the caller has 1048 * already called nfs_flush_incompatible() if necessary. 1049 */ 1050 static struct nfs_page * nfs_setup_write_request(struct nfs_open_context* ctx, 1051 struct page *page, unsigned int offset, unsigned int bytes) 1052 { 1053 struct inode *inode = page_file_mapping(page)->host; 1054 struct nfs_page *req; 1055 1056 req = nfs_try_to_update_request(inode, page, offset, bytes); 1057 if (req != NULL) 1058 goto out; 1059 req = nfs_create_request(ctx, page, NULL, offset, bytes); 1060 if (IS_ERR(req)) 1061 goto out; 1062 nfs_inode_add_request(inode, req); 1063 out: 1064 return req; 1065 } 1066 1067 static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page, 1068 unsigned int offset, unsigned int count) 1069 { 1070 struct nfs_page *req; 1071 1072 req = nfs_setup_write_request(ctx, page, offset, count); 1073 if (IS_ERR(req)) 1074 return PTR_ERR(req); 1075 /* Update file length */ 1076 nfs_grow_file(page, offset, count); 1077 nfs_mark_uptodate(req); 1078 nfs_mark_request_dirty(req); 1079 nfs_unlock_and_release_request(req); 1080 return 0; 1081 } 1082 1083 int nfs_flush_incompatible(struct file *file, struct page *page) 1084 { 1085 struct nfs_open_context *ctx = nfs_file_open_context(file); 1086 struct nfs_lock_context *l_ctx; 1087 struct nfs_page *req; 1088 int do_flush, status; 1089 /* 1090 * Look for a request corresponding to this page. If there 1091 * is one, and it belongs to another file, we flush it out 1092 * before we try to copy anything into the page. Do this 1093 * due to the lack of an ACCESS-type call in NFSv2. 1094 * Also do the same if we find a request from an existing 1095 * dropped page. 1096 */ 1097 do { 1098 req = nfs_page_find_head_request(page); 1099 if (req == NULL) 1100 return 0; 1101 l_ctx = req->wb_lock_context; 1102 do_flush = req->wb_page != page || req->wb_context != ctx; 1103 /* for now, flush if more than 1 request in page_group */ 1104 do_flush |= req->wb_this_page != req; 1105 if (l_ctx && ctx->dentry->d_inode->i_flock != NULL) { 1106 do_flush |= l_ctx->lockowner.l_owner != current->files 1107 || l_ctx->lockowner.l_pid != current->tgid; 1108 } 1109 nfs_release_request(req); 1110 if (!do_flush) 1111 return 0; 1112 status = nfs_wb_page(page_file_mapping(page)->host, page); 1113 } while (status == 0); 1114 return status; 1115 } 1116 1117 /* 1118 * Avoid buffered writes when a open context credential's key would 1119 * expire soon. 1120 * 1121 * Returns -EACCES if the key will expire within RPC_KEY_EXPIRE_FAIL. 1122 * 1123 * Return 0 and set a credential flag which triggers the inode to flush 1124 * and performs NFS_FILE_SYNC writes if the key will expired within 1125 * RPC_KEY_EXPIRE_TIMEO. 1126 */ 1127 int 1128 nfs_key_timeout_notify(struct file *filp, struct inode *inode) 1129 { 1130 struct nfs_open_context *ctx = nfs_file_open_context(filp); 1131 struct rpc_auth *auth = NFS_SERVER(inode)->client->cl_auth; 1132 1133 return rpcauth_key_timeout_notify(auth, ctx->cred); 1134 } 1135 1136 /* 1137 * Test if the open context credential key is marked to expire soon. 1138 */ 1139 bool nfs_ctx_key_to_expire(struct nfs_open_context *ctx) 1140 { 1141 return rpcauth_cred_key_to_expire(ctx->cred); 1142 } 1143 1144 /* 1145 * If the page cache is marked as unsafe or invalid, then we can't rely on 1146 * the PageUptodate() flag. In this case, we will need to turn off 1147 * write optimisations that depend on the page contents being correct. 1148 */ 1149 static bool nfs_write_pageuptodate(struct page *page, struct inode *inode) 1150 { 1151 struct nfs_inode *nfsi = NFS_I(inode); 1152 1153 if (nfs_have_delegated_attributes(inode)) 1154 goto out; 1155 if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) 1156 return false; 1157 smp_rmb(); 1158 if (test_bit(NFS_INO_INVALIDATING, &nfsi->flags)) 1159 return false; 1160 out: 1161 if (nfsi->cache_validity & NFS_INO_INVALID_DATA) 1162 return false; 1163 return PageUptodate(page) != 0; 1164 } 1165 1166 /* If we know the page is up to date, and we're not using byte range locks (or 1167 * if we have the whole file locked for writing), it may be more efficient to 1168 * extend the write to cover the entire page in order to avoid fragmentation 1169 * inefficiencies. 1170 * 1171 * If the file is opened for synchronous writes then we can just skip the rest 1172 * of the checks. 1173 */ 1174 static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode) 1175 { 1176 if (file->f_flags & O_DSYNC) 1177 return 0; 1178 if (!nfs_write_pageuptodate(page, inode)) 1179 return 0; 1180 if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) 1181 return 1; 1182 if (inode->i_flock == NULL || (inode->i_flock->fl_start == 0 && 1183 inode->i_flock->fl_end == OFFSET_MAX && 1184 inode->i_flock->fl_type != F_RDLCK)) 1185 return 1; 1186 return 0; 1187 } 1188 1189 /* 1190 * Update and possibly write a cached page of an NFS file. 1191 * 1192 * XXX: Keep an eye on generic_file_read to make sure it doesn't do bad 1193 * things with a page scheduled for an RPC call (e.g. invalidate it). 1194 */ 1195 int nfs_updatepage(struct file *file, struct page *page, 1196 unsigned int offset, unsigned int count) 1197 { 1198 struct nfs_open_context *ctx = nfs_file_open_context(file); 1199 struct inode *inode = page_file_mapping(page)->host; 1200 int status = 0; 1201 1202 nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE); 1203 1204 dprintk("NFS: nfs_updatepage(%pD2 %d@%lld)\n", 1205 file, count, (long long)(page_file_offset(page) + offset)); 1206 1207 if (nfs_can_extend_write(file, page, inode)) { 1208 count = max(count + offset, nfs_page_length(page)); 1209 offset = 0; 1210 } 1211 1212 status = nfs_writepage_setup(ctx, page, offset, count); 1213 if (status < 0) 1214 nfs_set_pageerror(page); 1215 else 1216 __set_page_dirty_nobuffers(page); 1217 1218 dprintk("NFS: nfs_updatepage returns %d (isize %lld)\n", 1219 status, (long long)i_size_read(inode)); 1220 return status; 1221 } 1222 1223 static int flush_task_priority(int how) 1224 { 1225 switch (how & (FLUSH_HIGHPRI|FLUSH_LOWPRI)) { 1226 case FLUSH_HIGHPRI: 1227 return RPC_PRIORITY_HIGH; 1228 case FLUSH_LOWPRI: 1229 return RPC_PRIORITY_LOW; 1230 } 1231 return RPC_PRIORITY_NORMAL; 1232 } 1233 1234 static void nfs_initiate_write(struct nfs_pgio_header *hdr, 1235 struct rpc_message *msg, 1236 struct rpc_task_setup *task_setup_data, int how) 1237 { 1238 struct inode *inode = hdr->inode; 1239 int priority = flush_task_priority(how); 1240 1241 task_setup_data->priority = priority; 1242 NFS_PROTO(inode)->write_setup(hdr, msg); 1243 1244 nfs4_state_protect_write(NFS_SERVER(inode)->nfs_client, 1245 &task_setup_data->rpc_client, msg, hdr); 1246 } 1247 1248 /* If a nfs_flush_* function fails, it should remove reqs from @head and 1249 * call this on each, which will prepare them to be retried on next 1250 * writeback using standard nfs. 1251 */ 1252 static void nfs_redirty_request(struct nfs_page *req) 1253 { 1254 nfs_mark_request_dirty(req); 1255 nfs_unlock_request(req); 1256 nfs_end_page_writeback(req); 1257 nfs_release_request(req); 1258 } 1259 1260 static void nfs_async_write_error(struct list_head *head) 1261 { 1262 struct nfs_page *req; 1263 1264 while (!list_empty(head)) { 1265 req = nfs_list_entry(head->next); 1266 nfs_list_remove_request(req); 1267 nfs_redirty_request(req); 1268 } 1269 } 1270 1271 static const struct nfs_pgio_completion_ops nfs_async_write_completion_ops = { 1272 .error_cleanup = nfs_async_write_error, 1273 .completion = nfs_write_completion, 1274 }; 1275 1276 void nfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, 1277 struct inode *inode, int ioflags, bool force_mds, 1278 const struct nfs_pgio_completion_ops *compl_ops) 1279 { 1280 struct nfs_server *server = NFS_SERVER(inode); 1281 const struct nfs_pageio_ops *pg_ops = &nfs_pgio_rw_ops; 1282 1283 #ifdef CONFIG_NFS_V4_1 1284 if (server->pnfs_curr_ld && !force_mds) 1285 pg_ops = server->pnfs_curr_ld->pg_write_ops; 1286 #endif 1287 nfs_pageio_init(pgio, inode, pg_ops, compl_ops, &nfs_rw_write_ops, 1288 server->wsize, ioflags); 1289 } 1290 EXPORT_SYMBOL_GPL(nfs_pageio_init_write); 1291 1292 void nfs_pageio_reset_write_mds(struct nfs_pageio_descriptor *pgio) 1293 { 1294 pgio->pg_ops = &nfs_pgio_rw_ops; 1295 pgio->pg_bsize = NFS_SERVER(pgio->pg_inode)->wsize; 1296 } 1297 EXPORT_SYMBOL_GPL(nfs_pageio_reset_write_mds); 1298 1299 1300 void nfs_commit_prepare(struct rpc_task *task, void *calldata) 1301 { 1302 struct nfs_commit_data *data = calldata; 1303 1304 NFS_PROTO(data->inode)->commit_rpc_prepare(task, data); 1305 } 1306 1307 static void nfs_writeback_release_common(struct nfs_pgio_header *hdr) 1308 { 1309 /* do nothing! */ 1310 } 1311 1312 /* 1313 * Special version of should_remove_suid() that ignores capabilities. 1314 */ 1315 static int nfs_should_remove_suid(const struct inode *inode) 1316 { 1317 umode_t mode = inode->i_mode; 1318 int kill = 0; 1319 1320 /* suid always must be killed */ 1321 if (unlikely(mode & S_ISUID)) 1322 kill = ATTR_KILL_SUID; 1323 1324 /* 1325 * sgid without any exec bits is just a mandatory locking mark; leave 1326 * it alone. If some exec bits are set, it's a real sgid; kill it. 1327 */ 1328 if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) 1329 kill |= ATTR_KILL_SGID; 1330 1331 if (unlikely(kill && S_ISREG(mode))) 1332 return kill; 1333 1334 return 0; 1335 } 1336 1337 /* 1338 * This function is called when the WRITE call is complete. 1339 */ 1340 static int nfs_writeback_done(struct rpc_task *task, 1341 struct nfs_pgio_header *hdr, 1342 struct inode *inode) 1343 { 1344 int status; 1345 1346 /* 1347 * ->write_done will attempt to use post-op attributes to detect 1348 * conflicting writes by other clients. A strict interpretation 1349 * of close-to-open would allow us to continue caching even if 1350 * another writer had changed the file, but some applications 1351 * depend on tighter cache coherency when writing. 1352 */ 1353 status = NFS_PROTO(inode)->write_done(task, hdr); 1354 if (status != 0) 1355 return status; 1356 nfs_add_stats(inode, NFSIOS_SERVERWRITTENBYTES, hdr->res.count); 1357 1358 if (hdr->res.verf->committed < hdr->args.stable && 1359 task->tk_status >= 0) { 1360 /* We tried a write call, but the server did not 1361 * commit data to stable storage even though we 1362 * requested it. 1363 * Note: There is a known bug in Tru64 < 5.0 in which 1364 * the server reports NFS_DATA_SYNC, but performs 1365 * NFS_FILE_SYNC. We therefore implement this checking 1366 * as a dprintk() in order to avoid filling syslog. 1367 */ 1368 static unsigned long complain; 1369 1370 /* Note this will print the MDS for a DS write */ 1371 if (time_before(complain, jiffies)) { 1372 dprintk("NFS: faulty NFS server %s:" 1373 " (committed = %d) != (stable = %d)\n", 1374 NFS_SERVER(inode)->nfs_client->cl_hostname, 1375 hdr->res.verf->committed, hdr->args.stable); 1376 complain = jiffies + 300 * HZ; 1377 } 1378 } 1379 1380 /* Deal with the suid/sgid bit corner case */ 1381 if (nfs_should_remove_suid(inode)) 1382 nfs_mark_for_revalidate(inode); 1383 return 0; 1384 } 1385 1386 /* 1387 * This function is called when the WRITE call is complete. 1388 */ 1389 static void nfs_writeback_result(struct rpc_task *task, 1390 struct nfs_pgio_header *hdr) 1391 { 1392 struct nfs_pgio_args *argp = &hdr->args; 1393 struct nfs_pgio_res *resp = &hdr->res; 1394 1395 if (resp->count < argp->count) { 1396 static unsigned long complain; 1397 1398 /* This a short write! */ 1399 nfs_inc_stats(hdr->inode, NFSIOS_SHORTWRITE); 1400 1401 /* Has the server at least made some progress? */ 1402 if (resp->count == 0) { 1403 if (time_before(complain, jiffies)) { 1404 printk(KERN_WARNING 1405 "NFS: Server wrote zero bytes, expected %u.\n", 1406 argp->count); 1407 complain = jiffies + 300 * HZ; 1408 } 1409 nfs_set_pgio_error(hdr, -EIO, argp->offset); 1410 task->tk_status = -EIO; 1411 return; 1412 } 1413 /* Was this an NFSv2 write or an NFSv3 stable write? */ 1414 if (resp->verf->committed != NFS_UNSTABLE) { 1415 /* Resend from where the server left off */ 1416 hdr->mds_offset += resp->count; 1417 argp->offset += resp->count; 1418 argp->pgbase += resp->count; 1419 argp->count -= resp->count; 1420 } else { 1421 /* Resend as a stable write in order to avoid 1422 * headaches in the case of a server crash. 1423 */ 1424 argp->stable = NFS_FILE_SYNC; 1425 } 1426 rpc_restart_call_prepare(task); 1427 } 1428 } 1429 1430 1431 static int nfs_commit_set_lock(struct nfs_inode *nfsi, int may_wait) 1432 { 1433 int ret; 1434 1435 if (!test_and_set_bit(NFS_INO_COMMIT, &nfsi->flags)) 1436 return 1; 1437 if (!may_wait) 1438 return 0; 1439 ret = out_of_line_wait_on_bit_lock(&nfsi->flags, 1440 NFS_INO_COMMIT, 1441 nfs_wait_bit_killable, 1442 TASK_KILLABLE); 1443 return (ret < 0) ? ret : 1; 1444 } 1445 1446 static void nfs_commit_clear_lock(struct nfs_inode *nfsi) 1447 { 1448 clear_bit(NFS_INO_COMMIT, &nfsi->flags); 1449 smp_mb__after_atomic(); 1450 wake_up_bit(&nfsi->flags, NFS_INO_COMMIT); 1451 } 1452 1453 void nfs_commitdata_release(struct nfs_commit_data *data) 1454 { 1455 put_nfs_open_context(data->context); 1456 nfs_commit_free(data); 1457 } 1458 EXPORT_SYMBOL_GPL(nfs_commitdata_release); 1459 1460 int nfs_initiate_commit(struct rpc_clnt *clnt, struct nfs_commit_data *data, 1461 const struct rpc_call_ops *call_ops, 1462 int how, int flags) 1463 { 1464 struct rpc_task *task; 1465 int priority = flush_task_priority(how); 1466 struct rpc_message msg = { 1467 .rpc_argp = &data->args, 1468 .rpc_resp = &data->res, 1469 .rpc_cred = data->cred, 1470 }; 1471 struct rpc_task_setup task_setup_data = { 1472 .task = &data->task, 1473 .rpc_client = clnt, 1474 .rpc_message = &msg, 1475 .callback_ops = call_ops, 1476 .callback_data = data, 1477 .workqueue = nfsiod_workqueue, 1478 .flags = RPC_TASK_ASYNC | flags, 1479 .priority = priority, 1480 }; 1481 /* Set up the initial task struct. */ 1482 NFS_PROTO(data->inode)->commit_setup(data, &msg); 1483 1484 dprintk("NFS: %5u initiated commit call\n", data->task.tk_pid); 1485 1486 nfs4_state_protect(NFS_SERVER(data->inode)->nfs_client, 1487 NFS_SP4_MACH_CRED_COMMIT, &task_setup_data.rpc_client, &msg); 1488 1489 task = rpc_run_task(&task_setup_data); 1490 if (IS_ERR(task)) 1491 return PTR_ERR(task); 1492 if (how & FLUSH_SYNC) 1493 rpc_wait_for_completion_task(task); 1494 rpc_put_task(task); 1495 return 0; 1496 } 1497 EXPORT_SYMBOL_GPL(nfs_initiate_commit); 1498 1499 static loff_t nfs_get_lwb(struct list_head *head) 1500 { 1501 loff_t lwb = 0; 1502 struct nfs_page *req; 1503 1504 list_for_each_entry(req, head, wb_list) 1505 if (lwb < (req_offset(req) + req->wb_bytes)) 1506 lwb = req_offset(req) + req->wb_bytes; 1507 1508 return lwb; 1509 } 1510 1511 /* 1512 * Set up the argument/result storage required for the RPC call. 1513 */ 1514 void nfs_init_commit(struct nfs_commit_data *data, 1515 struct list_head *head, 1516 struct pnfs_layout_segment *lseg, 1517 struct nfs_commit_info *cinfo) 1518 { 1519 struct nfs_page *first = nfs_list_entry(head->next); 1520 struct inode *inode = first->wb_context->dentry->d_inode; 1521 1522 /* Set up the RPC argument and reply structs 1523 * NB: take care not to mess about with data->commit et al. */ 1524 1525 list_splice_init(head, &data->pages); 1526 1527 data->inode = inode; 1528 data->cred = first->wb_context->cred; 1529 data->lseg = lseg; /* reference transferred */ 1530 /* only set lwb for pnfs commit */ 1531 if (lseg) 1532 data->lwb = nfs_get_lwb(&data->pages); 1533 data->mds_ops = &nfs_commit_ops; 1534 data->completion_ops = cinfo->completion_ops; 1535 data->dreq = cinfo->dreq; 1536 1537 data->args.fh = NFS_FH(data->inode); 1538 /* Note: we always request a commit of the entire inode */ 1539 data->args.offset = 0; 1540 data->args.count = 0; 1541 data->context = get_nfs_open_context(first->wb_context); 1542 data->res.fattr = &data->fattr; 1543 data->res.verf = &data->verf; 1544 nfs_fattr_init(&data->fattr); 1545 } 1546 EXPORT_SYMBOL_GPL(nfs_init_commit); 1547 1548 void nfs_retry_commit(struct list_head *page_list, 1549 struct pnfs_layout_segment *lseg, 1550 struct nfs_commit_info *cinfo) 1551 { 1552 struct nfs_page *req; 1553 1554 while (!list_empty(page_list)) { 1555 req = nfs_list_entry(page_list->next); 1556 nfs_list_remove_request(req); 1557 nfs_mark_request_commit(req, lseg, cinfo); 1558 if (!cinfo->dreq) { 1559 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS); 1560 dec_bdi_stat(page_file_mapping(req->wb_page)->backing_dev_info, 1561 BDI_RECLAIMABLE); 1562 } 1563 nfs_unlock_and_release_request(req); 1564 } 1565 } 1566 EXPORT_SYMBOL_GPL(nfs_retry_commit); 1567 1568 /* 1569 * Commit dirty pages 1570 */ 1571 static int 1572 nfs_commit_list(struct inode *inode, struct list_head *head, int how, 1573 struct nfs_commit_info *cinfo) 1574 { 1575 struct nfs_commit_data *data; 1576 1577 data = nfs_commitdata_alloc(); 1578 1579 if (!data) 1580 goto out_bad; 1581 1582 /* Set up the argument struct */ 1583 nfs_init_commit(data, head, NULL, cinfo); 1584 atomic_inc(&cinfo->mds->rpcs_out); 1585 return nfs_initiate_commit(NFS_CLIENT(inode), data, data->mds_ops, 1586 how, 0); 1587 out_bad: 1588 nfs_retry_commit(head, NULL, cinfo); 1589 cinfo->completion_ops->error_cleanup(NFS_I(inode)); 1590 return -ENOMEM; 1591 } 1592 1593 /* 1594 * COMMIT call returned 1595 */ 1596 static void nfs_commit_done(struct rpc_task *task, void *calldata) 1597 { 1598 struct nfs_commit_data *data = calldata; 1599 1600 dprintk("NFS: %5u nfs_commit_done (status %d)\n", 1601 task->tk_pid, task->tk_status); 1602 1603 /* Call the NFS version-specific code */ 1604 NFS_PROTO(data->inode)->commit_done(task, data); 1605 } 1606 1607 static void nfs_commit_release_pages(struct nfs_commit_data *data) 1608 { 1609 struct nfs_page *req; 1610 int status = data->task.tk_status; 1611 struct nfs_commit_info cinfo; 1612 struct nfs_server *nfss; 1613 1614 while (!list_empty(&data->pages)) { 1615 req = nfs_list_entry(data->pages.next); 1616 nfs_list_remove_request(req); 1617 nfs_clear_page_commit(req->wb_page); 1618 1619 dprintk("NFS: commit (%s/%llu %d@%lld)", 1620 req->wb_context->dentry->d_sb->s_id, 1621 (unsigned long long)NFS_FILEID(req->wb_context->dentry->d_inode), 1622 req->wb_bytes, 1623 (long long)req_offset(req)); 1624 if (status < 0) { 1625 nfs_context_set_write_error(req->wb_context, status); 1626 nfs_inode_remove_request(req); 1627 dprintk(", error = %d\n", status); 1628 goto next; 1629 } 1630 1631 /* Okay, COMMIT succeeded, apparently. Check the verifier 1632 * returned by the server against all stored verfs. */ 1633 if (!memcmp(&req->wb_verf, &data->verf.verifier, sizeof(req->wb_verf))) { 1634 /* We have a match */ 1635 nfs_inode_remove_request(req); 1636 dprintk(" OK\n"); 1637 goto next; 1638 } 1639 /* We have a mismatch. Write the page again */ 1640 dprintk(" mismatch\n"); 1641 nfs_mark_request_dirty(req); 1642 set_bit(NFS_CONTEXT_RESEND_WRITES, &req->wb_context->flags); 1643 next: 1644 nfs_unlock_and_release_request(req); 1645 } 1646 nfss = NFS_SERVER(data->inode); 1647 if (atomic_long_read(&nfss->writeback) < NFS_CONGESTION_OFF_THRESH) 1648 clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC); 1649 1650 nfs_init_cinfo(&cinfo, data->inode, data->dreq); 1651 if (atomic_dec_and_test(&cinfo.mds->rpcs_out)) 1652 nfs_commit_clear_lock(NFS_I(data->inode)); 1653 } 1654 1655 static void nfs_commit_release(void *calldata) 1656 { 1657 struct nfs_commit_data *data = calldata; 1658 1659 data->completion_ops->completion(data); 1660 nfs_commitdata_release(calldata); 1661 } 1662 1663 static const struct rpc_call_ops nfs_commit_ops = { 1664 .rpc_call_prepare = nfs_commit_prepare, 1665 .rpc_call_done = nfs_commit_done, 1666 .rpc_release = nfs_commit_release, 1667 }; 1668 1669 static const struct nfs_commit_completion_ops nfs_commit_completion_ops = { 1670 .completion = nfs_commit_release_pages, 1671 .error_cleanup = nfs_commit_clear_lock, 1672 }; 1673 1674 int nfs_generic_commit_list(struct inode *inode, struct list_head *head, 1675 int how, struct nfs_commit_info *cinfo) 1676 { 1677 int status; 1678 1679 status = pnfs_commit_list(inode, head, how, cinfo); 1680 if (status == PNFS_NOT_ATTEMPTED) 1681 status = nfs_commit_list(inode, head, how, cinfo); 1682 return status; 1683 } 1684 1685 int nfs_commit_inode(struct inode *inode, int how) 1686 { 1687 LIST_HEAD(head); 1688 struct nfs_commit_info cinfo; 1689 int may_wait = how & FLUSH_SYNC; 1690 int res; 1691 1692 res = nfs_commit_set_lock(NFS_I(inode), may_wait); 1693 if (res <= 0) 1694 goto out_mark_dirty; 1695 nfs_init_cinfo_from_inode(&cinfo, inode); 1696 res = nfs_scan_commit(inode, &head, &cinfo); 1697 if (res) { 1698 int error; 1699 1700 error = nfs_generic_commit_list(inode, &head, how, &cinfo); 1701 if (error < 0) 1702 return error; 1703 if (!may_wait) 1704 goto out_mark_dirty; 1705 error = wait_on_bit_action(&NFS_I(inode)->flags, 1706 NFS_INO_COMMIT, 1707 nfs_wait_bit_killable, 1708 TASK_KILLABLE); 1709 if (error < 0) 1710 return error; 1711 } else 1712 nfs_commit_clear_lock(NFS_I(inode)); 1713 return res; 1714 /* Note: If we exit without ensuring that the commit is complete, 1715 * we must mark the inode as dirty. Otherwise, future calls to 1716 * sync_inode() with the WB_SYNC_ALL flag set will fail to ensure 1717 * that the data is on the disk. 1718 */ 1719 out_mark_dirty: 1720 __mark_inode_dirty(inode, I_DIRTY_DATASYNC); 1721 return res; 1722 } 1723 1724 static int nfs_commit_unstable_pages(struct inode *inode, struct writeback_control *wbc) 1725 { 1726 struct nfs_inode *nfsi = NFS_I(inode); 1727 int flags = FLUSH_SYNC; 1728 int ret = 0; 1729 1730 /* no commits means nothing needs to be done */ 1731 if (!nfsi->commit_info.ncommit) 1732 return ret; 1733 1734 if (wbc->sync_mode == WB_SYNC_NONE) { 1735 /* Don't commit yet if this is a non-blocking flush and there 1736 * are a lot of outstanding writes for this mapping. 1737 */ 1738 if (nfsi->commit_info.ncommit <= (nfsi->npages >> 1)) 1739 goto out_mark_dirty; 1740 1741 /* don't wait for the COMMIT response */ 1742 flags = 0; 1743 } 1744 1745 ret = nfs_commit_inode(inode, flags); 1746 if (ret >= 0) { 1747 if (wbc->sync_mode == WB_SYNC_NONE) { 1748 if (ret < wbc->nr_to_write) 1749 wbc->nr_to_write -= ret; 1750 else 1751 wbc->nr_to_write = 0; 1752 } 1753 return 0; 1754 } 1755 out_mark_dirty: 1756 __mark_inode_dirty(inode, I_DIRTY_DATASYNC); 1757 return ret; 1758 } 1759 1760 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc) 1761 { 1762 return nfs_commit_unstable_pages(inode, wbc); 1763 } 1764 EXPORT_SYMBOL_GPL(nfs_write_inode); 1765 1766 /* 1767 * flush the inode to disk. 1768 */ 1769 int nfs_wb_all(struct inode *inode) 1770 { 1771 struct writeback_control wbc = { 1772 .sync_mode = WB_SYNC_ALL, 1773 .nr_to_write = LONG_MAX, 1774 .range_start = 0, 1775 .range_end = LLONG_MAX, 1776 }; 1777 int ret; 1778 1779 trace_nfs_writeback_inode_enter(inode); 1780 1781 ret = sync_inode(inode, &wbc); 1782 1783 trace_nfs_writeback_inode_exit(inode, ret); 1784 return ret; 1785 } 1786 EXPORT_SYMBOL_GPL(nfs_wb_all); 1787 1788 int nfs_wb_page_cancel(struct inode *inode, struct page *page) 1789 { 1790 struct nfs_page *req; 1791 int ret = 0; 1792 1793 wait_on_page_writeback(page); 1794 1795 /* blocking call to cancel all requests and join to a single (head) 1796 * request */ 1797 req = nfs_lock_and_join_requests(page, false); 1798 1799 if (IS_ERR(req)) { 1800 ret = PTR_ERR(req); 1801 } else if (req) { 1802 /* all requests from this page have been cancelled by 1803 * nfs_lock_and_join_requests, so just remove the head 1804 * request from the inode / page_private pointer and 1805 * release it */ 1806 nfs_inode_remove_request(req); 1807 /* 1808 * In case nfs_inode_remove_request has marked the 1809 * page as being dirty 1810 */ 1811 cancel_dirty_page(page, PAGE_CACHE_SIZE); 1812 nfs_unlock_and_release_request(req); 1813 } 1814 1815 return ret; 1816 } 1817 1818 /* 1819 * Write back all requests on one page - we do this before reading it. 1820 */ 1821 int nfs_wb_page(struct inode *inode, struct page *page) 1822 { 1823 loff_t range_start = page_file_offset(page); 1824 loff_t range_end = range_start + (loff_t)(PAGE_CACHE_SIZE - 1); 1825 struct writeback_control wbc = { 1826 .sync_mode = WB_SYNC_ALL, 1827 .nr_to_write = 0, 1828 .range_start = range_start, 1829 .range_end = range_end, 1830 }; 1831 int ret; 1832 1833 trace_nfs_writeback_page_enter(inode); 1834 1835 for (;;) { 1836 wait_on_page_writeback(page); 1837 if (clear_page_dirty_for_io(page)) { 1838 ret = nfs_writepage_locked(page, &wbc); 1839 if (ret < 0) 1840 goto out_error; 1841 continue; 1842 } 1843 ret = 0; 1844 if (!PagePrivate(page)) 1845 break; 1846 ret = nfs_commit_inode(inode, FLUSH_SYNC); 1847 if (ret < 0) 1848 goto out_error; 1849 } 1850 out_error: 1851 trace_nfs_writeback_page_exit(inode, ret); 1852 return ret; 1853 } 1854 1855 #ifdef CONFIG_MIGRATION 1856 int nfs_migrate_page(struct address_space *mapping, struct page *newpage, 1857 struct page *page, enum migrate_mode mode) 1858 { 1859 /* 1860 * If PagePrivate is set, then the page is currently associated with 1861 * an in-progress read or write request. Don't try to migrate it. 1862 * 1863 * FIXME: we could do this in principle, but we'll need a way to ensure 1864 * that we can safely release the inode reference while holding 1865 * the page lock. 1866 */ 1867 if (PagePrivate(page)) 1868 return -EBUSY; 1869 1870 if (!nfs_fscache_release_page(page, GFP_KERNEL)) 1871 return -EBUSY; 1872 1873 return migrate_page(mapping, newpage, page, mode); 1874 } 1875 #endif 1876 1877 int __init nfs_init_writepagecache(void) 1878 { 1879 nfs_wdata_cachep = kmem_cache_create("nfs_write_data", 1880 sizeof(struct nfs_pgio_header), 1881 0, SLAB_HWCACHE_ALIGN, 1882 NULL); 1883 if (nfs_wdata_cachep == NULL) 1884 return -ENOMEM; 1885 1886 nfs_wdata_mempool = mempool_create_slab_pool(MIN_POOL_WRITE, 1887 nfs_wdata_cachep); 1888 if (nfs_wdata_mempool == NULL) 1889 goto out_destroy_write_cache; 1890 1891 nfs_cdata_cachep = kmem_cache_create("nfs_commit_data", 1892 sizeof(struct nfs_commit_data), 1893 0, SLAB_HWCACHE_ALIGN, 1894 NULL); 1895 if (nfs_cdata_cachep == NULL) 1896 goto out_destroy_write_mempool; 1897 1898 nfs_commit_mempool = mempool_create_slab_pool(MIN_POOL_COMMIT, 1899 nfs_cdata_cachep); 1900 if (nfs_commit_mempool == NULL) 1901 goto out_destroy_commit_cache; 1902 1903 /* 1904 * NFS congestion size, scale with available memory. 1905 * 1906 * 64MB: 8192k 1907 * 128MB: 11585k 1908 * 256MB: 16384k 1909 * 512MB: 23170k 1910 * 1GB: 32768k 1911 * 2GB: 46340k 1912 * 4GB: 65536k 1913 * 8GB: 92681k 1914 * 16GB: 131072k 1915 * 1916 * This allows larger machines to have larger/more transfers. 1917 * Limit the default to 256M 1918 */ 1919 nfs_congestion_kb = (16*int_sqrt(totalram_pages)) << (PAGE_SHIFT-10); 1920 if (nfs_congestion_kb > 256*1024) 1921 nfs_congestion_kb = 256*1024; 1922 1923 return 0; 1924 1925 out_destroy_commit_cache: 1926 kmem_cache_destroy(nfs_cdata_cachep); 1927 out_destroy_write_mempool: 1928 mempool_destroy(nfs_wdata_mempool); 1929 out_destroy_write_cache: 1930 kmem_cache_destroy(nfs_wdata_cachep); 1931 return -ENOMEM; 1932 } 1933 1934 void nfs_destroy_writepagecache(void) 1935 { 1936 mempool_destroy(nfs_commit_mempool); 1937 kmem_cache_destroy(nfs_cdata_cachep); 1938 mempool_destroy(nfs_wdata_mempool); 1939 kmem_cache_destroy(nfs_wdata_cachep); 1940 } 1941 1942 static const struct nfs_rw_ops nfs_rw_write_ops = { 1943 .rw_mode = FMODE_WRITE, 1944 .rw_alloc_header = nfs_writehdr_alloc, 1945 .rw_free_header = nfs_writehdr_free, 1946 .rw_release = nfs_writeback_release_common, 1947 .rw_done = nfs_writeback_done, 1948 .rw_result = nfs_writeback_result, 1949 .rw_initiate = nfs_initiate_write, 1950 }; 1951