1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/fs/nfs/file.c 4 * 5 * Copyright (C) 1992 Rick Sladkey 6 * 7 * Changes Copyright (C) 1994 by Florian La Roche 8 * - Do not copy data too often around in the kernel. 9 * - In nfs_file_read the return value of kmalloc wasn't checked. 10 * - Put in a better version of read look-ahead buffering. Original idea 11 * and implementation by Wai S Kok elekokws@ee.nus.sg. 12 * 13 * Expire cache on write to a file by Wai S Kok (Oct 1994). 14 * 15 * Total rewrite of read side for new NFS buffer cache.. Linus. 16 * 17 * nfs regular file handling functions 18 */ 19 20 #include <linux/module.h> 21 #include <linux/time.h> 22 #include <linux/kernel.h> 23 #include <linux/errno.h> 24 #include <linux/fcntl.h> 25 #include <linux/stat.h> 26 #include <linux/nfs_fs.h> 27 #include <linux/nfs_mount.h> 28 #include <linux/mm.h> 29 #include <linux/pagemap.h> 30 #include <linux/gfp.h> 31 #include <linux/swap.h> 32 33 #include <linux/uaccess.h> 34 35 #include "delegation.h" 36 #include "internal.h" 37 #include "iostat.h" 38 #include "fscache.h" 39 #include "pnfs.h" 40 41 #include "nfstrace.h" 42 43 #define NFSDBG_FACILITY NFSDBG_FILE 44 45 static const struct vm_operations_struct nfs_file_vm_ops; 46 47 int nfs_check_flags(int flags) 48 { 49 if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT)) 50 return -EINVAL; 51 52 return 0; 53 } 54 EXPORT_SYMBOL_GPL(nfs_check_flags); 55 56 /* 57 * Open file 58 */ 59 static int 60 nfs_file_open(struct inode *inode, struct file *filp) 61 { 62 int res; 63 64 dprintk("NFS: open file(%pD2)\n", filp); 65 66 nfs_inc_stats(inode, NFSIOS_VFSOPEN); 67 res = nfs_check_flags(filp->f_flags); 68 if (res) 69 return res; 70 71 res = nfs_open(inode, filp); 72 return res; 73 } 74 75 int 76 nfs_file_release(struct inode *inode, struct file *filp) 77 { 78 dprintk("NFS: release(%pD2)\n", filp); 79 80 nfs_inc_stats(inode, NFSIOS_VFSRELEASE); 81 nfs_file_clear_open_context(filp); 82 nfs_fscache_release_file(inode, filp); 83 return 0; 84 } 85 EXPORT_SYMBOL_GPL(nfs_file_release); 86 87 /** 88 * nfs_revalidate_file_size - Revalidate the file size 89 * @inode: pointer to inode struct 90 * @filp: pointer to struct file 91 * 92 * Revalidates the file length. This is basically a wrapper around 93 * nfs_revalidate_inode() that takes into account the fact that we may 94 * have cached writes (in which case we don't care about the server's 95 * idea of what the file length is), or O_DIRECT (in which case we 96 * shouldn't trust the cache). 97 */ 98 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp) 99 { 100 struct nfs_server *server = NFS_SERVER(inode); 101 102 if (filp->f_flags & O_DIRECT) 103 goto force_reval; 104 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_SIZE)) 105 goto force_reval; 106 return 0; 107 force_reval: 108 return __nfs_revalidate_inode(server, inode); 109 } 110 111 loff_t nfs_file_llseek(struct file *filp, loff_t offset, int whence) 112 { 113 dprintk("NFS: llseek file(%pD2, %lld, %d)\n", 114 filp, offset, whence); 115 116 /* 117 * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate 118 * the cached file length 119 */ 120 if (whence != SEEK_SET && whence != SEEK_CUR) { 121 struct inode *inode = filp->f_mapping->host; 122 123 int retval = nfs_revalidate_file_size(inode, filp); 124 if (retval < 0) 125 return (loff_t)retval; 126 } 127 128 return generic_file_llseek(filp, offset, whence); 129 } 130 EXPORT_SYMBOL_GPL(nfs_file_llseek); 131 132 /* 133 * Flush all dirty pages, and check for write errors. 134 */ 135 static int 136 nfs_file_flush(struct file *file, fl_owner_t id) 137 { 138 struct inode *inode = file_inode(file); 139 errseq_t since; 140 141 dprintk("NFS: flush(%pD2)\n", file); 142 143 nfs_inc_stats(inode, NFSIOS_VFSFLUSH); 144 if ((file->f_mode & FMODE_WRITE) == 0) 145 return 0; 146 147 /* Flush writes to the server and return any errors */ 148 since = filemap_sample_wb_err(file->f_mapping); 149 nfs_wb_all(inode); 150 return filemap_check_wb_err(file->f_mapping, since); 151 } 152 153 ssize_t 154 nfs_file_read(struct kiocb *iocb, struct iov_iter *to) 155 { 156 struct inode *inode = file_inode(iocb->ki_filp); 157 ssize_t result; 158 159 if (iocb->ki_flags & IOCB_DIRECT) 160 return nfs_file_direct_read(iocb, to, false); 161 162 dprintk("NFS: read(%pD2, %zu@%lu)\n", 163 iocb->ki_filp, 164 iov_iter_count(to), (unsigned long) iocb->ki_pos); 165 166 nfs_start_io_read(inode); 167 result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping); 168 if (!result) { 169 result = generic_file_read_iter(iocb, to); 170 if (result > 0) 171 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result); 172 } 173 nfs_end_io_read(inode); 174 return result; 175 } 176 EXPORT_SYMBOL_GPL(nfs_file_read); 177 178 int 179 nfs_file_mmap(struct file * file, struct vm_area_struct * vma) 180 { 181 struct inode *inode = file_inode(file); 182 int status; 183 184 dprintk("NFS: mmap(%pD2)\n", file); 185 186 /* Note: generic_file_mmap() returns ENOSYS on nommu systems 187 * so we call that before revalidating the mapping 188 */ 189 status = generic_file_mmap(file, vma); 190 if (!status) { 191 vma->vm_ops = &nfs_file_vm_ops; 192 status = nfs_revalidate_mapping(inode, file->f_mapping); 193 } 194 return status; 195 } 196 EXPORT_SYMBOL_GPL(nfs_file_mmap); 197 198 /* 199 * Flush any dirty pages for this process, and check for write errors. 200 * The return status from this call provides a reliable indication of 201 * whether any write errors occurred for this process. 202 */ 203 static int 204 nfs_file_fsync_commit(struct file *file, int datasync) 205 { 206 struct inode *inode = file_inode(file); 207 int ret; 208 209 dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync); 210 211 nfs_inc_stats(inode, NFSIOS_VFSFSYNC); 212 ret = nfs_commit_inode(inode, FLUSH_SYNC); 213 if (ret < 0) 214 return ret; 215 return file_check_and_advance_wb_err(file); 216 } 217 218 int 219 nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync) 220 { 221 struct nfs_open_context *ctx = nfs_file_open_context(file); 222 struct inode *inode = file_inode(file); 223 int ret; 224 225 trace_nfs_fsync_enter(inode); 226 227 for (;;) { 228 ret = file_write_and_wait_range(file, start, end); 229 if (ret != 0) 230 break; 231 ret = nfs_file_fsync_commit(file, datasync); 232 if (ret != 0) 233 break; 234 ret = pnfs_sync_inode(inode, !!datasync); 235 if (ret != 0) 236 break; 237 if (!test_and_clear_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags)) 238 break; 239 /* 240 * If nfs_file_fsync_commit detected a server reboot, then 241 * resend all dirty pages that might have been covered by 242 * the NFS_CONTEXT_RESEND_WRITES flag 243 */ 244 start = 0; 245 end = LLONG_MAX; 246 } 247 248 trace_nfs_fsync_exit(inode, ret); 249 return ret; 250 } 251 EXPORT_SYMBOL_GPL(nfs_file_fsync); 252 253 /* 254 * Decide whether a read/modify/write cycle may be more efficient 255 * then a modify/write/read cycle when writing to a page in the 256 * page cache. 257 * 258 * Some pNFS layout drivers can only read/write at a certain block 259 * granularity like all block devices and therefore we must perform 260 * read/modify/write whenever a page hasn't read yet and the data 261 * to be written there is not aligned to a block boundary and/or 262 * smaller than the block size. 263 * 264 * The modify/write/read cycle may occur if a page is read before 265 * being completely filled by the writer. In this situation, the 266 * page must be completely written to stable storage on the server 267 * before it can be refilled by reading in the page from the server. 268 * This can lead to expensive, small, FILE_SYNC mode writes being 269 * done. 270 * 271 * It may be more efficient to read the page first if the file is 272 * open for reading in addition to writing, the page is not marked 273 * as Uptodate, it is not dirty or waiting to be committed, 274 * indicating that it was previously allocated and then modified, 275 * that there were valid bytes of data in that range of the file, 276 * and that the new data won't completely replace the old data in 277 * that range of the file. 278 */ 279 static bool nfs_full_page_write(struct page *page, loff_t pos, unsigned int len) 280 { 281 unsigned int pglen = nfs_page_length(page); 282 unsigned int offset = pos & (PAGE_SIZE - 1); 283 unsigned int end = offset + len; 284 285 return !pglen || (end >= pglen && !offset); 286 } 287 288 static bool nfs_want_read_modify_write(struct file *file, struct page *page, 289 loff_t pos, unsigned int len) 290 { 291 /* 292 * Up-to-date pages, those with ongoing or full-page write 293 * don't need read/modify/write 294 */ 295 if (PageUptodate(page) || PagePrivate(page) || 296 nfs_full_page_write(page, pos, len)) 297 return false; 298 299 if (pnfs_ld_read_whole_page(file->f_mapping->host)) 300 return true; 301 /* Open for reading too? */ 302 if (file->f_mode & FMODE_READ) 303 return true; 304 return false; 305 } 306 307 /* 308 * This does the "real" work of the write. We must allocate and lock the 309 * page to be sent back to the generic routine, which then copies the 310 * data from user space. 311 * 312 * If the writer ends up delaying the write, the writer needs to 313 * increment the page use counts until he is done with the page. 314 */ 315 static int nfs_write_begin(struct file *file, struct address_space *mapping, 316 loff_t pos, unsigned len, unsigned flags, 317 struct page **pagep, void **fsdata) 318 { 319 int ret; 320 pgoff_t index = pos >> PAGE_SHIFT; 321 struct page *page; 322 int once_thru = 0; 323 324 dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n", 325 file, mapping->host->i_ino, len, (long long) pos); 326 327 start: 328 page = grab_cache_page_write_begin(mapping, index, flags); 329 if (!page) 330 return -ENOMEM; 331 *pagep = page; 332 333 ret = nfs_flush_incompatible(file, page); 334 if (ret) { 335 unlock_page(page); 336 put_page(page); 337 } else if (!once_thru && 338 nfs_want_read_modify_write(file, page, pos, len)) { 339 once_thru = 1; 340 ret = nfs_readpage(file, page); 341 put_page(page); 342 if (!ret) 343 goto start; 344 } 345 return ret; 346 } 347 348 static int nfs_write_end(struct file *file, struct address_space *mapping, 349 loff_t pos, unsigned len, unsigned copied, 350 struct page *page, void *fsdata) 351 { 352 unsigned offset = pos & (PAGE_SIZE - 1); 353 struct nfs_open_context *ctx = nfs_file_open_context(file); 354 int status; 355 356 dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n", 357 file, mapping->host->i_ino, len, (long long) pos); 358 359 /* 360 * Zero any uninitialised parts of the page, and then mark the page 361 * as up to date if it turns out that we're extending the file. 362 */ 363 if (!PageUptodate(page)) { 364 unsigned pglen = nfs_page_length(page); 365 unsigned end = offset + copied; 366 367 if (pglen == 0) { 368 zero_user_segments(page, 0, offset, 369 end, PAGE_SIZE); 370 SetPageUptodate(page); 371 } else if (end >= pglen) { 372 zero_user_segment(page, end, PAGE_SIZE); 373 if (offset == 0) 374 SetPageUptodate(page); 375 } else 376 zero_user_segment(page, pglen, PAGE_SIZE); 377 } 378 379 status = nfs_updatepage(file, page, offset, copied); 380 381 unlock_page(page); 382 put_page(page); 383 384 if (status < 0) 385 return status; 386 NFS_I(mapping->host)->write_io += copied; 387 388 if (nfs_ctx_key_to_expire(ctx, mapping->host)) { 389 status = nfs_wb_all(mapping->host); 390 if (status < 0) 391 return status; 392 } 393 394 return copied; 395 } 396 397 /* 398 * Partially or wholly invalidate a page 399 * - Release the private state associated with a page if undergoing complete 400 * page invalidation 401 * - Called if either PG_private or PG_fscache is set on the page 402 * - Caller holds page lock 403 */ 404 static void nfs_invalidate_folio(struct folio *folio, size_t offset, 405 size_t length) 406 { 407 dfprintk(PAGECACHE, "NFS: invalidate_folio(%lu, %zu, %zu)\n", 408 folio->index, offset, length); 409 410 if (offset != 0 || length < folio_size(folio)) 411 return; 412 /* Cancel any unstarted writes on this page */ 413 nfs_wb_folio_cancel(folio->mapping->host, folio); 414 folio_wait_fscache(folio); 415 } 416 417 /* 418 * Attempt to release the private state associated with a page 419 * - Called if either PG_private or PG_fscache is set on the page 420 * - Caller holds page lock 421 * - Return true (may release page) or false (may not) 422 */ 423 static int nfs_release_page(struct page *page, gfp_t gfp) 424 { 425 dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page); 426 427 /* If PagePrivate() is set, then the page is not freeable */ 428 if (PagePrivate(page)) 429 return 0; 430 return nfs_fscache_release_page(page, gfp); 431 } 432 433 static void nfs_check_dirty_writeback(struct page *page, 434 bool *dirty, bool *writeback) 435 { 436 struct nfs_inode *nfsi; 437 struct address_space *mapping = page_file_mapping(page); 438 439 if (!mapping || PageSwapCache(page)) 440 return; 441 442 /* 443 * Check if an unstable page is currently being committed and 444 * if so, have the VM treat it as if the page is under writeback 445 * so it will not block due to pages that will shortly be freeable. 446 */ 447 nfsi = NFS_I(mapping->host); 448 if (atomic_read(&nfsi->commit_info.rpcs_out)) { 449 *writeback = true; 450 return; 451 } 452 453 /* 454 * If PagePrivate() is set, then the page is not freeable and as the 455 * inode is not being committed, it's not going to be cleaned in the 456 * near future so treat it as dirty 457 */ 458 if (PagePrivate(page)) 459 *dirty = true; 460 } 461 462 /* 463 * Attempt to clear the private state associated with a page when an error 464 * occurs that requires the cached contents of an inode to be written back or 465 * destroyed 466 * - Called if either PG_private or fscache is set on the page 467 * - Caller holds page lock 468 * - Return 0 if successful, -error otherwise 469 */ 470 static int nfs_launder_folio(struct folio *folio) 471 { 472 struct inode *inode = folio->mapping->host; 473 474 dfprintk(PAGECACHE, "NFS: launder_folio(%ld, %llu)\n", 475 inode->i_ino, folio_pos(folio)); 476 477 folio_wait_fscache(folio); 478 return nfs_wb_page(inode, &folio->page); 479 } 480 481 static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file, 482 sector_t *span) 483 { 484 unsigned long blocks; 485 long long isize; 486 struct inode *inode = file_inode(file); 487 struct rpc_clnt *clnt = NFS_CLIENT(inode); 488 struct nfs_client *cl = NFS_SERVER(inode)->nfs_client; 489 490 spin_lock(&inode->i_lock); 491 blocks = inode->i_blocks; 492 isize = inode->i_size; 493 spin_unlock(&inode->i_lock); 494 if (blocks*512 < isize) { 495 pr_warn("swap activate: swapfile has holes\n"); 496 return -EINVAL; 497 } 498 499 *span = sis->pages; 500 501 502 if (cl->rpc_ops->enable_swap) 503 cl->rpc_ops->enable_swap(inode); 504 505 return rpc_clnt_swap_activate(clnt); 506 } 507 508 static void nfs_swap_deactivate(struct file *file) 509 { 510 struct inode *inode = file_inode(file); 511 struct rpc_clnt *clnt = NFS_CLIENT(inode); 512 struct nfs_client *cl = NFS_SERVER(inode)->nfs_client; 513 514 rpc_clnt_swap_deactivate(clnt); 515 if (cl->rpc_ops->disable_swap) 516 cl->rpc_ops->disable_swap(file_inode(file)); 517 } 518 519 const struct address_space_operations nfs_file_aops = { 520 .readpage = nfs_readpage, 521 .readahead = nfs_readahead, 522 .dirty_folio = filemap_dirty_folio, 523 .writepage = nfs_writepage, 524 .writepages = nfs_writepages, 525 .write_begin = nfs_write_begin, 526 .write_end = nfs_write_end, 527 .invalidate_folio = nfs_invalidate_folio, 528 .releasepage = nfs_release_page, 529 .direct_IO = nfs_direct_IO, 530 #ifdef CONFIG_MIGRATION 531 .migratepage = nfs_migrate_page, 532 #endif 533 .launder_folio = nfs_launder_folio, 534 .is_dirty_writeback = nfs_check_dirty_writeback, 535 .error_remove_page = generic_error_remove_page, 536 .swap_activate = nfs_swap_activate, 537 .swap_deactivate = nfs_swap_deactivate, 538 }; 539 540 /* 541 * Notification that a PTE pointing to an NFS page is about to be made 542 * writable, implying that someone is about to modify the page through a 543 * shared-writable mapping 544 */ 545 static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf) 546 { 547 struct page *page = vmf->page; 548 struct file *filp = vmf->vma->vm_file; 549 struct inode *inode = file_inode(filp); 550 unsigned pagelen; 551 vm_fault_t ret = VM_FAULT_NOPAGE; 552 struct address_space *mapping; 553 554 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n", 555 filp, filp->f_mapping->host->i_ino, 556 (long long)page_offset(page)); 557 558 sb_start_pagefault(inode->i_sb); 559 560 /* make sure the cache has finished storing the page */ 561 if (PageFsCache(page) && 562 wait_on_page_fscache_killable(vmf->page) < 0) { 563 ret = VM_FAULT_RETRY; 564 goto out; 565 } 566 567 wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING, 568 nfs_wait_bit_killable, TASK_KILLABLE); 569 570 lock_page(page); 571 mapping = page_file_mapping(page); 572 if (mapping != inode->i_mapping) 573 goto out_unlock; 574 575 wait_on_page_writeback(page); 576 577 pagelen = nfs_page_length(page); 578 if (pagelen == 0) 579 goto out_unlock; 580 581 ret = VM_FAULT_LOCKED; 582 if (nfs_flush_incompatible(filp, page) == 0 && 583 nfs_updatepage(filp, page, 0, pagelen) == 0) 584 goto out; 585 586 ret = VM_FAULT_SIGBUS; 587 out_unlock: 588 unlock_page(page); 589 out: 590 sb_end_pagefault(inode->i_sb); 591 return ret; 592 } 593 594 static const struct vm_operations_struct nfs_file_vm_ops = { 595 .fault = filemap_fault, 596 .map_pages = filemap_map_pages, 597 .page_mkwrite = nfs_vm_page_mkwrite, 598 }; 599 600 static int nfs_need_check_write(struct file *filp, struct inode *inode, 601 int error) 602 { 603 struct nfs_open_context *ctx; 604 605 ctx = nfs_file_open_context(filp); 606 if (nfs_error_is_fatal_on_server(error) || 607 nfs_ctx_key_to_expire(ctx, inode)) 608 return 1; 609 return 0; 610 } 611 612 ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from) 613 { 614 struct file *file = iocb->ki_filp; 615 struct inode *inode = file_inode(file); 616 unsigned int mntflags = NFS_SERVER(inode)->flags; 617 ssize_t result, written; 618 errseq_t since; 619 int error; 620 621 result = nfs_key_timeout_notify(file, inode); 622 if (result) 623 return result; 624 625 if (iocb->ki_flags & IOCB_DIRECT) 626 return nfs_file_direct_write(iocb, from, false); 627 628 dprintk("NFS: write(%pD2, %zu@%Ld)\n", 629 file, iov_iter_count(from), (long long) iocb->ki_pos); 630 631 if (IS_SWAPFILE(inode)) 632 goto out_swapfile; 633 /* 634 * O_APPEND implies that we must revalidate the file length. 635 */ 636 if (iocb->ki_flags & IOCB_APPEND || iocb->ki_pos > i_size_read(inode)) { 637 result = nfs_revalidate_file_size(inode, file); 638 if (result) 639 goto out; 640 } 641 642 nfs_clear_invalid_mapping(file->f_mapping); 643 644 since = filemap_sample_wb_err(file->f_mapping); 645 nfs_start_io_write(inode); 646 result = generic_write_checks(iocb, from); 647 if (result > 0) { 648 current->backing_dev_info = inode_to_bdi(inode); 649 result = generic_perform_write(file, from, iocb->ki_pos); 650 current->backing_dev_info = NULL; 651 } 652 nfs_end_io_write(inode); 653 if (result <= 0) 654 goto out; 655 656 written = result; 657 iocb->ki_pos += written; 658 659 if (mntflags & NFS_MOUNT_WRITE_EAGER) { 660 result = filemap_fdatawrite_range(file->f_mapping, 661 iocb->ki_pos - written, 662 iocb->ki_pos - 1); 663 if (result < 0) 664 goto out; 665 } 666 if (mntflags & NFS_MOUNT_WRITE_WAIT) { 667 result = filemap_fdatawait_range(file->f_mapping, 668 iocb->ki_pos - written, 669 iocb->ki_pos - 1); 670 if (result < 0) 671 goto out; 672 } 673 result = generic_write_sync(iocb, written); 674 if (result < 0) 675 goto out; 676 677 /* Return error values */ 678 error = filemap_check_wb_err(file->f_mapping, since); 679 if (nfs_need_check_write(file, inode, error)) { 680 int err = nfs_wb_all(inode); 681 if (err < 0) 682 result = err; 683 } 684 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written); 685 out: 686 return result; 687 688 out_swapfile: 689 printk(KERN_INFO "NFS: attempt to write to active swap file!\n"); 690 return -ETXTBSY; 691 } 692 EXPORT_SYMBOL_GPL(nfs_file_write); 693 694 static int 695 do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) 696 { 697 struct inode *inode = filp->f_mapping->host; 698 int status = 0; 699 unsigned int saved_type = fl->fl_type; 700 701 /* Try local locking first */ 702 posix_test_lock(filp, fl); 703 if (fl->fl_type != F_UNLCK) { 704 /* found a conflict */ 705 goto out; 706 } 707 fl->fl_type = saved_type; 708 709 if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) 710 goto out_noconflict; 711 712 if (is_local) 713 goto out_noconflict; 714 715 status = NFS_PROTO(inode)->lock(filp, cmd, fl); 716 out: 717 return status; 718 out_noconflict: 719 fl->fl_type = F_UNLCK; 720 goto out; 721 } 722 723 static int 724 do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) 725 { 726 struct inode *inode = filp->f_mapping->host; 727 struct nfs_lock_context *l_ctx; 728 int status; 729 730 /* 731 * Flush all pending writes before doing anything 732 * with locks.. 733 */ 734 nfs_wb_all(inode); 735 736 l_ctx = nfs_get_lock_context(nfs_file_open_context(filp)); 737 if (!IS_ERR(l_ctx)) { 738 status = nfs_iocounter_wait(l_ctx); 739 nfs_put_lock_context(l_ctx); 740 /* NOTE: special case 741 * If we're signalled while cleaning up locks on process exit, we 742 * still need to complete the unlock. 743 */ 744 if (status < 0 && !(fl->fl_flags & FL_CLOSE)) 745 return status; 746 } 747 748 /* 749 * Use local locking if mounted with "-onolock" or with appropriate 750 * "-olocal_lock=" 751 */ 752 if (!is_local) 753 status = NFS_PROTO(inode)->lock(filp, cmd, fl); 754 else 755 status = locks_lock_file_wait(filp, fl); 756 return status; 757 } 758 759 static int 760 do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) 761 { 762 struct inode *inode = filp->f_mapping->host; 763 int status; 764 765 /* 766 * Flush all pending writes before doing anything 767 * with locks.. 768 */ 769 status = nfs_sync_mapping(filp->f_mapping); 770 if (status != 0) 771 goto out; 772 773 /* 774 * Use local locking if mounted with "-onolock" or with appropriate 775 * "-olocal_lock=" 776 */ 777 if (!is_local) 778 status = NFS_PROTO(inode)->lock(filp, cmd, fl); 779 else 780 status = locks_lock_file_wait(filp, fl); 781 if (status < 0) 782 goto out; 783 784 /* 785 * Invalidate cache to prevent missing any changes. If 786 * the file is mapped, clear the page cache as well so 787 * those mappings will be loaded. 788 * 789 * This makes locking act as a cache coherency point. 790 */ 791 nfs_sync_mapping(filp->f_mapping); 792 if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) { 793 nfs_zap_caches(inode); 794 if (mapping_mapped(filp->f_mapping)) 795 nfs_revalidate_mapping(inode, filp->f_mapping); 796 } 797 out: 798 return status; 799 } 800 801 /* 802 * Lock a (portion of) a file 803 */ 804 int nfs_lock(struct file *filp, int cmd, struct file_lock *fl) 805 { 806 struct inode *inode = filp->f_mapping->host; 807 int ret = -ENOLCK; 808 int is_local = 0; 809 810 dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n", 811 filp, fl->fl_type, fl->fl_flags, 812 (long long)fl->fl_start, (long long)fl->fl_end); 813 814 nfs_inc_stats(inode, NFSIOS_VFSLOCK); 815 816 if (fl->fl_flags & FL_RECLAIM) 817 return -ENOGRACE; 818 819 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL) 820 is_local = 1; 821 822 if (NFS_PROTO(inode)->lock_check_bounds != NULL) { 823 ret = NFS_PROTO(inode)->lock_check_bounds(fl); 824 if (ret < 0) 825 goto out_err; 826 } 827 828 if (IS_GETLK(cmd)) 829 ret = do_getlk(filp, cmd, fl, is_local); 830 else if (fl->fl_type == F_UNLCK) 831 ret = do_unlk(filp, cmd, fl, is_local); 832 else 833 ret = do_setlk(filp, cmd, fl, is_local); 834 out_err: 835 return ret; 836 } 837 EXPORT_SYMBOL_GPL(nfs_lock); 838 839 /* 840 * Lock a (portion of) a file 841 */ 842 int nfs_flock(struct file *filp, int cmd, struct file_lock *fl) 843 { 844 struct inode *inode = filp->f_mapping->host; 845 int is_local = 0; 846 847 dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n", 848 filp, fl->fl_type, fl->fl_flags); 849 850 if (!(fl->fl_flags & FL_FLOCK)) 851 return -ENOLCK; 852 853 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK) 854 is_local = 1; 855 856 /* We're simulating flock() locks using posix locks on the server */ 857 if (fl->fl_type == F_UNLCK) 858 return do_unlk(filp, cmd, fl, is_local); 859 return do_setlk(filp, cmd, fl, is_local); 860 } 861 EXPORT_SYMBOL_GPL(nfs_flock); 862 863 const struct file_operations nfs_file_operations = { 864 .llseek = nfs_file_llseek, 865 .read_iter = nfs_file_read, 866 .write_iter = nfs_file_write, 867 .mmap = nfs_file_mmap, 868 .open = nfs_file_open, 869 .flush = nfs_file_flush, 870 .release = nfs_file_release, 871 .fsync = nfs_file_fsync, 872 .lock = nfs_lock, 873 .flock = nfs_flock, 874 .splice_read = generic_file_splice_read, 875 .splice_write = iter_file_splice_write, 876 .check_flags = nfs_check_flags, 877 .setlease = simple_nosetlease, 878 }; 879 EXPORT_SYMBOL_GPL(nfs_file_operations); 880