1 /* 2 * linux/fs/nfs/file.c 3 * 4 * Copyright (C) 1992 Rick Sladkey 5 * 6 * Changes Copyright (C) 1994 by Florian La Roche 7 * - Do not copy data too often around in the kernel. 8 * - In nfs_file_read the return value of kmalloc wasn't checked. 9 * - Put in a better version of read look-ahead buffering. Original idea 10 * and implementation by Wai S Kok elekokws@ee.nus.sg. 11 * 12 * Expire cache on write to a file by Wai S Kok (Oct 1994). 13 * 14 * Total rewrite of read side for new NFS buffer cache.. Linus. 15 * 16 * nfs regular file handling functions 17 */ 18 19 #include <linux/module.h> 20 #include <linux/time.h> 21 #include <linux/kernel.h> 22 #include <linux/errno.h> 23 #include <linux/fcntl.h> 24 #include <linux/stat.h> 25 #include <linux/nfs_fs.h> 26 #include <linux/nfs_mount.h> 27 #include <linux/mm.h> 28 #include <linux/pagemap.h> 29 #include <linux/aio.h> 30 #include <linux/gfp.h> 31 #include <linux/swap.h> 32 33 #include <asm/uaccess.h> 34 35 #include "delegation.h" 36 #include "internal.h" 37 #include "iostat.h" 38 #include "fscache.h" 39 40 #define NFSDBG_FACILITY NFSDBG_FILE 41 42 static const struct vm_operations_struct nfs_file_vm_ops; 43 44 /* Hack for future NFS swap support */ 45 #ifndef IS_SWAPFILE 46 # define IS_SWAPFILE(inode) (0) 47 #endif 48 49 int nfs_check_flags(int flags) 50 { 51 if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT)) 52 return -EINVAL; 53 54 return 0; 55 } 56 EXPORT_SYMBOL_GPL(nfs_check_flags); 57 58 /* 59 * Open file 60 */ 61 static int 62 nfs_file_open(struct inode *inode, struct file *filp) 63 { 64 int res; 65 66 dprintk("NFS: open file(%s/%s)\n", 67 filp->f_path.dentry->d_parent->d_name.name, 68 filp->f_path.dentry->d_name.name); 69 70 nfs_inc_stats(inode, NFSIOS_VFSOPEN); 71 res = nfs_check_flags(filp->f_flags); 72 if (res) 73 return res; 74 75 res = nfs_open(inode, filp); 76 return res; 77 } 78 79 int 80 nfs_file_release(struct inode *inode, struct file *filp) 81 { 82 dprintk("NFS: release(%s/%s)\n", 83 filp->f_path.dentry->d_parent->d_name.name, 84 filp->f_path.dentry->d_name.name); 85 86 nfs_inc_stats(inode, NFSIOS_VFSRELEASE); 87 return nfs_release(inode, filp); 88 } 89 EXPORT_SYMBOL_GPL(nfs_file_release); 90 91 /** 92 * nfs_revalidate_size - Revalidate the file size 93 * @inode - pointer to inode struct 94 * @file - pointer to struct file 95 * 96 * Revalidates the file length. This is basically a wrapper around 97 * nfs_revalidate_inode() that takes into account the fact that we may 98 * have cached writes (in which case we don't care about the server's 99 * idea of what the file length is), or O_DIRECT (in which case we 100 * shouldn't trust the cache). 101 */ 102 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp) 103 { 104 struct nfs_server *server = NFS_SERVER(inode); 105 struct nfs_inode *nfsi = NFS_I(inode); 106 107 if (nfs_have_delegated_attributes(inode)) 108 goto out_noreval; 109 110 if (filp->f_flags & O_DIRECT) 111 goto force_reval; 112 if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) 113 goto force_reval; 114 if (nfs_attribute_timeout(inode)) 115 goto force_reval; 116 out_noreval: 117 return 0; 118 force_reval: 119 return __nfs_revalidate_inode(server, inode); 120 } 121 122 loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin) 123 { 124 dprintk("NFS: llseek file(%s/%s, %lld, %d)\n", 125 filp->f_path.dentry->d_parent->d_name.name, 126 filp->f_path.dentry->d_name.name, 127 offset, origin); 128 129 /* 130 * origin == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate 131 * the cached file length 132 */ 133 if (origin != SEEK_SET && origin != SEEK_CUR) { 134 struct inode *inode = filp->f_mapping->host; 135 136 int retval = nfs_revalidate_file_size(inode, filp); 137 if (retval < 0) 138 return (loff_t)retval; 139 } 140 141 return generic_file_llseek(filp, offset, origin); 142 } 143 EXPORT_SYMBOL_GPL(nfs_file_llseek); 144 145 /* 146 * Flush all dirty pages, and check for write errors. 147 */ 148 int 149 nfs_file_flush(struct file *file, fl_owner_t id) 150 { 151 struct dentry *dentry = file->f_path.dentry; 152 struct inode *inode = dentry->d_inode; 153 154 dprintk("NFS: flush(%s/%s)\n", 155 dentry->d_parent->d_name.name, 156 dentry->d_name.name); 157 158 nfs_inc_stats(inode, NFSIOS_VFSFLUSH); 159 if ((file->f_mode & FMODE_WRITE) == 0) 160 return 0; 161 162 /* 163 * If we're holding a write delegation, then just start the i/o 164 * but don't wait for completion (or send a commit). 165 */ 166 if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE)) 167 return filemap_fdatawrite(file->f_mapping); 168 169 /* Flush writes to the server and return any errors */ 170 return vfs_fsync(file, 0); 171 } 172 EXPORT_SYMBOL_GPL(nfs_file_flush); 173 174 ssize_t 175 nfs_file_read(struct kiocb *iocb, const struct iovec *iov, 176 unsigned long nr_segs, loff_t pos) 177 { 178 struct dentry * dentry = iocb->ki_filp->f_path.dentry; 179 struct inode * inode = dentry->d_inode; 180 ssize_t result; 181 182 if (iocb->ki_filp->f_flags & O_DIRECT) 183 return nfs_file_direct_read(iocb, iov, nr_segs, pos, true); 184 185 dprintk("NFS: read(%s/%s, %lu@%lu)\n", 186 dentry->d_parent->d_name.name, dentry->d_name.name, 187 (unsigned long) iov_length(iov, nr_segs), (unsigned long) pos); 188 189 result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping); 190 if (!result) { 191 result = generic_file_aio_read(iocb, iov, nr_segs, pos); 192 if (result > 0) 193 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result); 194 } 195 return result; 196 } 197 EXPORT_SYMBOL_GPL(nfs_file_read); 198 199 ssize_t 200 nfs_file_splice_read(struct file *filp, loff_t *ppos, 201 struct pipe_inode_info *pipe, size_t count, 202 unsigned int flags) 203 { 204 struct dentry *dentry = filp->f_path.dentry; 205 struct inode *inode = dentry->d_inode; 206 ssize_t res; 207 208 dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n", 209 dentry->d_parent->d_name.name, dentry->d_name.name, 210 (unsigned long) count, (unsigned long long) *ppos); 211 212 res = nfs_revalidate_mapping(inode, filp->f_mapping); 213 if (!res) { 214 res = generic_file_splice_read(filp, ppos, pipe, count, flags); 215 if (res > 0) 216 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, res); 217 } 218 return res; 219 } 220 EXPORT_SYMBOL_GPL(nfs_file_splice_read); 221 222 int 223 nfs_file_mmap(struct file * file, struct vm_area_struct * vma) 224 { 225 struct dentry *dentry = file->f_path.dentry; 226 struct inode *inode = dentry->d_inode; 227 int status; 228 229 dprintk("NFS: mmap(%s/%s)\n", 230 dentry->d_parent->d_name.name, dentry->d_name.name); 231 232 /* Note: generic_file_mmap() returns ENOSYS on nommu systems 233 * so we call that before revalidating the mapping 234 */ 235 status = generic_file_mmap(file, vma); 236 if (!status) { 237 vma->vm_ops = &nfs_file_vm_ops; 238 status = nfs_revalidate_mapping(inode, file->f_mapping); 239 } 240 return status; 241 } 242 EXPORT_SYMBOL_GPL(nfs_file_mmap); 243 244 /* 245 * Flush any dirty pages for this process, and check for write errors. 246 * The return status from this call provides a reliable indication of 247 * whether any write errors occurred for this process. 248 * 249 * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to 250 * disk, but it retrieves and clears ctx->error after synching, despite 251 * the two being set at the same time in nfs_context_set_write_error(). 252 * This is because the former is used to notify the _next_ call to 253 * nfs_file_write() that a write error occurred, and hence cause it to 254 * fall back to doing a synchronous write. 255 */ 256 int 257 nfs_file_fsync_commit(struct file *file, loff_t start, loff_t end, int datasync) 258 { 259 struct dentry *dentry = file->f_path.dentry; 260 struct nfs_open_context *ctx = nfs_file_open_context(file); 261 struct inode *inode = dentry->d_inode; 262 int have_error, status; 263 int ret = 0; 264 265 dprintk("NFS: fsync file(%s/%s) datasync %d\n", 266 dentry->d_parent->d_name.name, dentry->d_name.name, 267 datasync); 268 269 nfs_inc_stats(inode, NFSIOS_VFSFSYNC); 270 have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags); 271 status = nfs_commit_inode(inode, FLUSH_SYNC); 272 if (status >= 0 && ret < 0) 273 status = ret; 274 have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags); 275 if (have_error) 276 ret = xchg(&ctx->error, 0); 277 if (!ret && status < 0) 278 ret = status; 279 return ret; 280 } 281 EXPORT_SYMBOL_GPL(nfs_file_fsync_commit); 282 283 static int 284 nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync) 285 { 286 int ret; 287 struct inode *inode = file->f_path.dentry->d_inode; 288 289 ret = filemap_write_and_wait_range(inode->i_mapping, start, end); 290 if (ret != 0) 291 goto out; 292 mutex_lock(&inode->i_mutex); 293 ret = nfs_file_fsync_commit(file, start, end, datasync); 294 mutex_unlock(&inode->i_mutex); 295 out: 296 return ret; 297 } 298 299 /* 300 * Decide whether a read/modify/write cycle may be more efficient 301 * then a modify/write/read cycle when writing to a page in the 302 * page cache. 303 * 304 * The modify/write/read cycle may occur if a page is read before 305 * being completely filled by the writer. In this situation, the 306 * page must be completely written to stable storage on the server 307 * before it can be refilled by reading in the page from the server. 308 * This can lead to expensive, small, FILE_SYNC mode writes being 309 * done. 310 * 311 * It may be more efficient to read the page first if the file is 312 * open for reading in addition to writing, the page is not marked 313 * as Uptodate, it is not dirty or waiting to be committed, 314 * indicating that it was previously allocated and then modified, 315 * that there were valid bytes of data in that range of the file, 316 * and that the new data won't completely replace the old data in 317 * that range of the file. 318 */ 319 static int nfs_want_read_modify_write(struct file *file, struct page *page, 320 loff_t pos, unsigned len) 321 { 322 unsigned int pglen = nfs_page_length(page); 323 unsigned int offset = pos & (PAGE_CACHE_SIZE - 1); 324 unsigned int end = offset + len; 325 326 if ((file->f_mode & FMODE_READ) && /* open for read? */ 327 !PageUptodate(page) && /* Uptodate? */ 328 !PagePrivate(page) && /* i/o request already? */ 329 pglen && /* valid bytes of file? */ 330 (end < pglen || offset)) /* replace all valid bytes? */ 331 return 1; 332 return 0; 333 } 334 335 /* 336 * This does the "real" work of the write. We must allocate and lock the 337 * page to be sent back to the generic routine, which then copies the 338 * data from user space. 339 * 340 * If the writer ends up delaying the write, the writer needs to 341 * increment the page use counts until he is done with the page. 342 */ 343 static int nfs_write_begin(struct file *file, struct address_space *mapping, 344 loff_t pos, unsigned len, unsigned flags, 345 struct page **pagep, void **fsdata) 346 { 347 int ret; 348 pgoff_t index = pos >> PAGE_CACHE_SHIFT; 349 struct page *page; 350 int once_thru = 0; 351 352 dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n", 353 file->f_path.dentry->d_parent->d_name.name, 354 file->f_path.dentry->d_name.name, 355 mapping->host->i_ino, len, (long long) pos); 356 357 start: 358 /* 359 * Prevent starvation issues if someone is doing a consistency 360 * sync-to-disk 361 */ 362 ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING, 363 nfs_wait_bit_killable, TASK_KILLABLE); 364 if (ret) 365 return ret; 366 367 page = grab_cache_page_write_begin(mapping, index, flags); 368 if (!page) 369 return -ENOMEM; 370 *pagep = page; 371 372 ret = nfs_flush_incompatible(file, page); 373 if (ret) { 374 unlock_page(page); 375 page_cache_release(page); 376 } else if (!once_thru && 377 nfs_want_read_modify_write(file, page, pos, len)) { 378 once_thru = 1; 379 ret = nfs_readpage(file, page); 380 page_cache_release(page); 381 if (!ret) 382 goto start; 383 } 384 return ret; 385 } 386 387 static int nfs_write_end(struct file *file, struct address_space *mapping, 388 loff_t pos, unsigned len, unsigned copied, 389 struct page *page, void *fsdata) 390 { 391 unsigned offset = pos & (PAGE_CACHE_SIZE - 1); 392 int status; 393 394 dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n", 395 file->f_path.dentry->d_parent->d_name.name, 396 file->f_path.dentry->d_name.name, 397 mapping->host->i_ino, len, (long long) pos); 398 399 /* 400 * Zero any uninitialised parts of the page, and then mark the page 401 * as up to date if it turns out that we're extending the file. 402 */ 403 if (!PageUptodate(page)) { 404 unsigned pglen = nfs_page_length(page); 405 unsigned end = offset + len; 406 407 if (pglen == 0) { 408 zero_user_segments(page, 0, offset, 409 end, PAGE_CACHE_SIZE); 410 SetPageUptodate(page); 411 } else if (end >= pglen) { 412 zero_user_segment(page, end, PAGE_CACHE_SIZE); 413 if (offset == 0) 414 SetPageUptodate(page); 415 } else 416 zero_user_segment(page, pglen, PAGE_CACHE_SIZE); 417 } 418 419 status = nfs_updatepage(file, page, offset, copied); 420 421 unlock_page(page); 422 page_cache_release(page); 423 424 if (status < 0) 425 return status; 426 NFS_I(mapping->host)->write_io += copied; 427 return copied; 428 } 429 430 /* 431 * Partially or wholly invalidate a page 432 * - Release the private state associated with a page if undergoing complete 433 * page invalidation 434 * - Called if either PG_private or PG_fscache is set on the page 435 * - Caller holds page lock 436 */ 437 static void nfs_invalidate_page(struct page *page, unsigned long offset) 438 { 439 dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset); 440 441 if (offset != 0) 442 return; 443 /* Cancel any unstarted writes on this page */ 444 nfs_wb_page_cancel(page_file_mapping(page)->host, page); 445 446 nfs_fscache_invalidate_page(page, page->mapping->host); 447 } 448 449 /* 450 * Attempt to release the private state associated with a page 451 * - Called if either PG_private or PG_fscache is set on the page 452 * - Caller holds page lock 453 * - Return true (may release page) or false (may not) 454 */ 455 static int nfs_release_page(struct page *page, gfp_t gfp) 456 { 457 struct address_space *mapping = page->mapping; 458 459 dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page); 460 461 /* Only do I/O if gfp is a superset of GFP_KERNEL, and we're not 462 * doing this memory reclaim for a fs-related allocation. 463 */ 464 if (mapping && (gfp & GFP_KERNEL) == GFP_KERNEL && 465 !(current->flags & PF_FSTRANS)) { 466 int how = FLUSH_SYNC; 467 468 /* Don't let kswapd deadlock waiting for OOM RPC calls */ 469 if (current_is_kswapd()) 470 how = 0; 471 nfs_commit_inode(mapping->host, how); 472 } 473 /* If PagePrivate() is set, then the page is not freeable */ 474 if (PagePrivate(page)) 475 return 0; 476 return nfs_fscache_release_page(page, gfp); 477 } 478 479 /* 480 * Attempt to clear the private state associated with a page when an error 481 * occurs that requires the cached contents of an inode to be written back or 482 * destroyed 483 * - Called if either PG_private or fscache is set on the page 484 * - Caller holds page lock 485 * - Return 0 if successful, -error otherwise 486 */ 487 static int nfs_launder_page(struct page *page) 488 { 489 struct inode *inode = page_file_mapping(page)->host; 490 struct nfs_inode *nfsi = NFS_I(inode); 491 492 dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n", 493 inode->i_ino, (long long)page_offset(page)); 494 495 nfs_fscache_wait_on_page_write(nfsi, page); 496 return nfs_wb_page(inode, page); 497 } 498 499 #ifdef CONFIG_NFS_SWAP 500 static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file, 501 sector_t *span) 502 { 503 *span = sis->pages; 504 return xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 1); 505 } 506 507 static void nfs_swap_deactivate(struct file *file) 508 { 509 xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 0); 510 } 511 #endif 512 513 const struct address_space_operations nfs_file_aops = { 514 .readpage = nfs_readpage, 515 .readpages = nfs_readpages, 516 .set_page_dirty = __set_page_dirty_nobuffers, 517 .writepage = nfs_writepage, 518 .writepages = nfs_writepages, 519 .write_begin = nfs_write_begin, 520 .write_end = nfs_write_end, 521 .invalidatepage = nfs_invalidate_page, 522 .releasepage = nfs_release_page, 523 .direct_IO = nfs_direct_IO, 524 .migratepage = nfs_migrate_page, 525 .launder_page = nfs_launder_page, 526 .error_remove_page = generic_error_remove_page, 527 #ifdef CONFIG_NFS_SWAP 528 .swap_activate = nfs_swap_activate, 529 .swap_deactivate = nfs_swap_deactivate, 530 #endif 531 }; 532 533 /* 534 * Notification that a PTE pointing to an NFS page is about to be made 535 * writable, implying that someone is about to modify the page through a 536 * shared-writable mapping 537 */ 538 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) 539 { 540 struct page *page = vmf->page; 541 struct file *filp = vma->vm_file; 542 struct dentry *dentry = filp->f_path.dentry; 543 unsigned pagelen; 544 int ret = VM_FAULT_NOPAGE; 545 struct address_space *mapping; 546 547 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n", 548 dentry->d_parent->d_name.name, dentry->d_name.name, 549 filp->f_mapping->host->i_ino, 550 (long long)page_offset(page)); 551 552 /* make sure the cache has finished storing the page */ 553 nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page); 554 555 lock_page(page); 556 mapping = page_file_mapping(page); 557 if (mapping != dentry->d_inode->i_mapping) 558 goto out_unlock; 559 560 wait_on_page_writeback(page); 561 562 pagelen = nfs_page_length(page); 563 if (pagelen == 0) 564 goto out_unlock; 565 566 ret = VM_FAULT_LOCKED; 567 if (nfs_flush_incompatible(filp, page) == 0 && 568 nfs_updatepage(filp, page, 0, pagelen) == 0) 569 goto out; 570 571 ret = VM_FAULT_SIGBUS; 572 out_unlock: 573 unlock_page(page); 574 out: 575 return ret; 576 } 577 578 static const struct vm_operations_struct nfs_file_vm_ops = { 579 .fault = filemap_fault, 580 .page_mkwrite = nfs_vm_page_mkwrite, 581 }; 582 583 static int nfs_need_sync_write(struct file *filp, struct inode *inode) 584 { 585 struct nfs_open_context *ctx; 586 587 if (IS_SYNC(inode) || (filp->f_flags & O_DSYNC)) 588 return 1; 589 ctx = nfs_file_open_context(filp); 590 if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags)) 591 return 1; 592 return 0; 593 } 594 595 ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov, 596 unsigned long nr_segs, loff_t pos) 597 { 598 struct dentry * dentry = iocb->ki_filp->f_path.dentry; 599 struct inode * inode = dentry->d_inode; 600 unsigned long written = 0; 601 ssize_t result; 602 size_t count = iov_length(iov, nr_segs); 603 604 if (iocb->ki_filp->f_flags & O_DIRECT) 605 return nfs_file_direct_write(iocb, iov, nr_segs, pos, true); 606 607 dprintk("NFS: write(%s/%s, %lu@%Ld)\n", 608 dentry->d_parent->d_name.name, dentry->d_name.name, 609 (unsigned long) count, (long long) pos); 610 611 result = -EBUSY; 612 if (IS_SWAPFILE(inode)) 613 goto out_swapfile; 614 /* 615 * O_APPEND implies that we must revalidate the file length. 616 */ 617 if (iocb->ki_filp->f_flags & O_APPEND) { 618 result = nfs_revalidate_file_size(inode, iocb->ki_filp); 619 if (result) 620 goto out; 621 } 622 623 result = count; 624 if (!count) 625 goto out; 626 627 result = generic_file_aio_write(iocb, iov, nr_segs, pos); 628 if (result > 0) 629 written = result; 630 631 /* Return error values for O_DSYNC and IS_SYNC() */ 632 if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) { 633 int err = vfs_fsync(iocb->ki_filp, 0); 634 if (err < 0) 635 result = err; 636 } 637 if (result > 0) 638 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written); 639 out: 640 return result; 641 642 out_swapfile: 643 printk(KERN_INFO "NFS: attempt to write to active swap file!\n"); 644 goto out; 645 } 646 EXPORT_SYMBOL_GPL(nfs_file_write); 647 648 ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe, 649 struct file *filp, loff_t *ppos, 650 size_t count, unsigned int flags) 651 { 652 struct dentry *dentry = filp->f_path.dentry; 653 struct inode *inode = dentry->d_inode; 654 unsigned long written = 0; 655 ssize_t ret; 656 657 dprintk("NFS splice_write(%s/%s, %lu@%llu)\n", 658 dentry->d_parent->d_name.name, dentry->d_name.name, 659 (unsigned long) count, (unsigned long long) *ppos); 660 661 /* 662 * The combination of splice and an O_APPEND destination is disallowed. 663 */ 664 665 ret = generic_file_splice_write(pipe, filp, ppos, count, flags); 666 if (ret > 0) 667 written = ret; 668 669 if (ret >= 0 && nfs_need_sync_write(filp, inode)) { 670 int err = vfs_fsync(filp, 0); 671 if (err < 0) 672 ret = err; 673 } 674 if (ret > 0) 675 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written); 676 return ret; 677 } 678 EXPORT_SYMBOL_GPL(nfs_file_splice_write); 679 680 static int 681 do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) 682 { 683 struct inode *inode = filp->f_mapping->host; 684 int status = 0; 685 unsigned int saved_type = fl->fl_type; 686 687 /* Try local locking first */ 688 posix_test_lock(filp, fl); 689 if (fl->fl_type != F_UNLCK) { 690 /* found a conflict */ 691 goto out; 692 } 693 fl->fl_type = saved_type; 694 695 if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) 696 goto out_noconflict; 697 698 if (is_local) 699 goto out_noconflict; 700 701 status = NFS_PROTO(inode)->lock(filp, cmd, fl); 702 out: 703 return status; 704 out_noconflict: 705 fl->fl_type = F_UNLCK; 706 goto out; 707 } 708 709 static int do_vfs_lock(struct file *file, struct file_lock *fl) 710 { 711 int res = 0; 712 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) { 713 case FL_POSIX: 714 res = posix_lock_file_wait(file, fl); 715 break; 716 case FL_FLOCK: 717 res = flock_lock_file_wait(file, fl); 718 break; 719 default: 720 BUG(); 721 } 722 return res; 723 } 724 725 static int 726 do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) 727 { 728 struct inode *inode = filp->f_mapping->host; 729 int status; 730 731 /* 732 * Flush all pending writes before doing anything 733 * with locks.. 734 */ 735 nfs_sync_mapping(filp->f_mapping); 736 737 /* NOTE: special case 738 * If we're signalled while cleaning up locks on process exit, we 739 * still need to complete the unlock. 740 */ 741 /* 742 * Use local locking if mounted with "-onolock" or with appropriate 743 * "-olocal_lock=" 744 */ 745 if (!is_local) 746 status = NFS_PROTO(inode)->lock(filp, cmd, fl); 747 else 748 status = do_vfs_lock(filp, fl); 749 return status; 750 } 751 752 static int 753 is_time_granular(struct timespec *ts) { 754 return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000)); 755 } 756 757 static int 758 do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) 759 { 760 struct inode *inode = filp->f_mapping->host; 761 int status; 762 763 /* 764 * Flush all pending writes before doing anything 765 * with locks.. 766 */ 767 status = nfs_sync_mapping(filp->f_mapping); 768 if (status != 0) 769 goto out; 770 771 /* 772 * Use local locking if mounted with "-onolock" or with appropriate 773 * "-olocal_lock=" 774 */ 775 if (!is_local) 776 status = NFS_PROTO(inode)->lock(filp, cmd, fl); 777 else 778 status = do_vfs_lock(filp, fl); 779 if (status < 0) 780 goto out; 781 782 /* 783 * Revalidate the cache if the server has time stamps granular 784 * enough to detect subsecond changes. Otherwise, clear the 785 * cache to prevent missing any changes. 786 * 787 * This makes locking act as a cache coherency point. 788 */ 789 nfs_sync_mapping(filp->f_mapping); 790 if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) { 791 if (is_time_granular(&NFS_SERVER(inode)->time_delta)) 792 __nfs_revalidate_inode(NFS_SERVER(inode), inode); 793 else 794 nfs_zap_caches(inode); 795 } 796 out: 797 return status; 798 } 799 800 /* 801 * Lock a (portion of) a file 802 */ 803 int nfs_lock(struct file *filp, int cmd, struct file_lock *fl) 804 { 805 struct inode *inode = filp->f_mapping->host; 806 int ret = -ENOLCK; 807 int is_local = 0; 808 809 dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n", 810 filp->f_path.dentry->d_parent->d_name.name, 811 filp->f_path.dentry->d_name.name, 812 fl->fl_type, fl->fl_flags, 813 (long long)fl->fl_start, (long long)fl->fl_end); 814 815 nfs_inc_stats(inode, NFSIOS_VFSLOCK); 816 817 /* No mandatory locks over NFS */ 818 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK) 819 goto out_err; 820 821 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL) 822 is_local = 1; 823 824 if (NFS_PROTO(inode)->lock_check_bounds != NULL) { 825 ret = NFS_PROTO(inode)->lock_check_bounds(fl); 826 if (ret < 0) 827 goto out_err; 828 } 829 830 if (IS_GETLK(cmd)) 831 ret = do_getlk(filp, cmd, fl, is_local); 832 else if (fl->fl_type == F_UNLCK) 833 ret = do_unlk(filp, cmd, fl, is_local); 834 else 835 ret = do_setlk(filp, cmd, fl, is_local); 836 out_err: 837 return ret; 838 } 839 EXPORT_SYMBOL_GPL(nfs_lock); 840 841 /* 842 * Lock a (portion of) a file 843 */ 844 int nfs_flock(struct file *filp, int cmd, struct file_lock *fl) 845 { 846 struct inode *inode = filp->f_mapping->host; 847 int is_local = 0; 848 849 dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n", 850 filp->f_path.dentry->d_parent->d_name.name, 851 filp->f_path.dentry->d_name.name, 852 fl->fl_type, fl->fl_flags); 853 854 if (!(fl->fl_flags & FL_FLOCK)) 855 return -ENOLCK; 856 857 /* 858 * The NFSv4 protocol doesn't support LOCK_MAND, which is not part of 859 * any standard. In principle we might be able to support LOCK_MAND 860 * on NFSv2/3 since NLMv3/4 support DOS share modes, but for now the 861 * NFS code is not set up for it. 862 */ 863 if (fl->fl_type & LOCK_MAND) 864 return -EINVAL; 865 866 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK) 867 is_local = 1; 868 869 /* We're simulating flock() locks using posix locks on the server */ 870 fl->fl_owner = (fl_owner_t)filp; 871 fl->fl_start = 0; 872 fl->fl_end = OFFSET_MAX; 873 874 if (fl->fl_type == F_UNLCK) 875 return do_unlk(filp, cmd, fl, is_local); 876 return do_setlk(filp, cmd, fl, is_local); 877 } 878 EXPORT_SYMBOL_GPL(nfs_flock); 879 880 /* 881 * There is no protocol support for leases, so we have no way to implement 882 * them correctly in the face of opens by other clients. 883 */ 884 int nfs_setlease(struct file *file, long arg, struct file_lock **fl) 885 { 886 dprintk("NFS: setlease(%s/%s, arg=%ld)\n", 887 file->f_path.dentry->d_parent->d_name.name, 888 file->f_path.dentry->d_name.name, arg); 889 return -EINVAL; 890 } 891 EXPORT_SYMBOL_GPL(nfs_setlease); 892 893 const struct file_operations nfs_file_operations = { 894 .llseek = nfs_file_llseek, 895 .read = do_sync_read, 896 .write = do_sync_write, 897 .aio_read = nfs_file_read, 898 .aio_write = nfs_file_write, 899 .mmap = nfs_file_mmap, 900 .open = nfs_file_open, 901 .flush = nfs_file_flush, 902 .release = nfs_file_release, 903 .fsync = nfs_file_fsync, 904 .lock = nfs_lock, 905 .flock = nfs_flock, 906 .splice_read = nfs_file_splice_read, 907 .splice_write = nfs_file_splice_write, 908 .check_flags = nfs_check_flags, 909 .setlease = nfs_setlease, 910 }; 911 EXPORT_SYMBOL_GPL(nfs_file_operations); 912