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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#include <linux/filelock.h>
35
36#include "delegation.h"
37#include "internal.h"
38#include "iostat.h"
39#include "fscache.h"
40#include "pnfs.h"
41
42#include "nfstrace.h"
43
44#define NFSDBG_FACILITY NFSDBG_FILE
45
46static const struct vm_operations_struct nfs_file_vm_ops;
47
48int nfs_check_flags(int flags)
49{
50 if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
51 return -EINVAL;
52
53 return 0;
54}
55EXPORT_SYMBOL_GPL(nfs_check_flags);
56
57/*
58 * Open file
59 */
60static int
61nfs_file_open(struct inode *inode, struct file *filp)
62{
63 int res;
64
65 dprintk("NFS: open file(%pD2)\n", filp);
66
67 nfs_inc_stats(inode, NFSIOS_VFSOPEN);
68 res = nfs_check_flags(filp->f_flags);
69 if (res)
70 return res;
71
72 res = nfs_open(inode, filp);
73 if (res == 0)
74 filp->f_mode |= FMODE_CAN_ODIRECT;
75 return res;
76}
77
78int
79nfs_file_release(struct inode *inode, struct file *filp)
80{
81 dprintk("NFS: release(%pD2)\n", filp);
82
83 nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
84 nfs_file_clear_open_context(filp);
85 nfs_fscache_release_file(inode, filp);
86 return 0;
87}
88EXPORT_SYMBOL_GPL(nfs_file_release);
89
90/**
91 * nfs_revalidate_file_size - Revalidate the file size
92 * @inode: pointer to inode struct
93 * @filp: pointer to struct file
94 *
95 * Revalidates the file length. This is basically a wrapper around
96 * nfs_revalidate_inode() that takes into account the fact that we may
97 * have cached writes (in which case we don't care about the server's
98 * idea of what the file length is), or O_DIRECT (in which case we
99 * shouldn't trust the cache).
100 */
101static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
102{
103 struct nfs_server *server = NFS_SERVER(inode);
104
105 if (filp->f_flags & O_DIRECT)
106 goto force_reval;
107 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_SIZE))
108 goto force_reval;
109 return 0;
110force_reval:
111 return __nfs_revalidate_inode(server, inode);
112}
113
114loff_t nfs_file_llseek(struct file *filp, loff_t offset, int whence)
115{
116 dprintk("NFS: llseek file(%pD2, %lld, %d)\n",
117 filp, offset, whence);
118
119 /*
120 * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
121 * the cached file length
122 */
123 if (whence != SEEK_SET && whence != SEEK_CUR) {
124 struct inode *inode = filp->f_mapping->host;
125
126 int retval = nfs_revalidate_file_size(inode, filp);
127 if (retval < 0)
128 return (loff_t)retval;
129 }
130
131 return generic_file_llseek(filp, offset, whence);
132}
133EXPORT_SYMBOL_GPL(nfs_file_llseek);
134
135/*
136 * Flush all dirty pages, and check for write errors.
137 */
138static int
139nfs_file_flush(struct file *file, fl_owner_t id)
140{
141 struct inode *inode = file_inode(file);
142 errseq_t since;
143
144 dprintk("NFS: flush(%pD2)\n", file);
145
146 nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
147 if ((file->f_mode & FMODE_WRITE) == 0)
148 return 0;
149
150 /* Flush writes to the server and return any errors */
151 since = filemap_sample_wb_err(file->f_mapping);
152 nfs_wb_all(inode);
153 return filemap_check_wb_err(file->f_mapping, since);
154}
155
156ssize_t
157nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
158{
159 struct inode *inode = file_inode(iocb->ki_filp);
160 ssize_t result;
161
162 if (iocb->ki_flags & IOCB_DIRECT)
163 return nfs_file_direct_read(iocb, to, false);
164
165 dprintk("NFS: read(%pD2, %zu@%lu)\n",
166 iocb->ki_filp,
167 iov_iter_count(to), (unsigned long) iocb->ki_pos);
168
169 nfs_start_io_read(inode);
170 result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
171 if (!result) {
172 result = generic_file_read_iter(iocb, to);
173 if (result > 0)
174 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
175 }
176 nfs_end_io_read(inode);
177 return result;
178}
179EXPORT_SYMBOL_GPL(nfs_file_read);
180
181ssize_t
182nfs_file_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe,
183 size_t len, unsigned int flags)
184{
185 struct inode *inode = file_inode(in);
186 ssize_t result;
187
188 dprintk("NFS: splice_read(%pD2, %zu@%llu)\n", in, len, *ppos);
189
190 nfs_start_io_read(inode);
191 result = nfs_revalidate_mapping(inode, in->f_mapping);
192 if (!result) {
193 result = filemap_splice_read(in, ppos, pipe, len, flags);
194 if (result > 0)
195 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
196 }
197 nfs_end_io_read(inode);
198 return result;
199}
200EXPORT_SYMBOL_GPL(nfs_file_splice_read);
201
202int
203nfs_file_mmap(struct file *file, struct vm_area_struct *vma)
204{
205 struct inode *inode = file_inode(file);
206 int status;
207
208 dprintk("NFS: mmap(%pD2)\n", file);
209
210 /* Note: generic_file_mmap() returns ENOSYS on nommu systems
211 * so we call that before revalidating the mapping
212 */
213 status = generic_file_mmap(file, vma);
214 if (!status) {
215 vma->vm_ops = &nfs_file_vm_ops;
216 status = nfs_revalidate_mapping(inode, file->f_mapping);
217 }
218 return status;
219}
220EXPORT_SYMBOL_GPL(nfs_file_mmap);
221
222/*
223 * Flush any dirty pages for this process, and check for write errors.
224 * The return status from this call provides a reliable indication of
225 * whether any write errors occurred for this process.
226 */
227static int
228nfs_file_fsync_commit(struct file *file, int datasync)
229{
230 struct inode *inode = file_inode(file);
231 int ret, ret2;
232
233 dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
234
235 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
236 ret = nfs_commit_inode(inode, FLUSH_SYNC);
237 ret2 = file_check_and_advance_wb_err(file);
238 if (ret2 < 0)
239 return ret2;
240 return ret;
241}
242
243int
244nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
245{
246 struct inode *inode = file_inode(file);
247 struct nfs_inode *nfsi = NFS_I(inode);
248 long save_nredirtied = atomic_long_read(&nfsi->redirtied_pages);
249 long nredirtied;
250 int ret;
251
252 trace_nfs_fsync_enter(inode);
253
254 for (;;) {
255 ret = file_write_and_wait_range(file, start, end);
256 if (ret != 0)
257 break;
258 ret = nfs_file_fsync_commit(file, datasync);
259 if (ret != 0)
260 break;
261 ret = pnfs_sync_inode(inode, !!datasync);
262 if (ret != 0)
263 break;
264 nredirtied = atomic_long_read(&nfsi->redirtied_pages);
265 if (nredirtied == save_nredirtied)
266 break;
267 save_nredirtied = nredirtied;
268 }
269
270 trace_nfs_fsync_exit(inode, ret);
271 return ret;
272}
273EXPORT_SYMBOL_GPL(nfs_file_fsync);
274
275/*
276 * Decide whether a read/modify/write cycle may be more efficient
277 * then a modify/write/read cycle when writing to a page in the
278 * page cache.
279 *
280 * Some pNFS layout drivers can only read/write at a certain block
281 * granularity like all block devices and therefore we must perform
282 * read/modify/write whenever a page hasn't read yet and the data
283 * to be written there is not aligned to a block boundary and/or
284 * smaller than the block size.
285 *
286 * The modify/write/read cycle may occur if a page is read before
287 * being completely filled by the writer. In this situation, the
288 * page must be completely written to stable storage on the server
289 * before it can be refilled by reading in the page from the server.
290 * This can lead to expensive, small, FILE_SYNC mode writes being
291 * done.
292 *
293 * It may be more efficient to read the page first if the file is
294 * open for reading in addition to writing, the page is not marked
295 * as Uptodate, it is not dirty or waiting to be committed,
296 * indicating that it was previously allocated and then modified,
297 * that there were valid bytes of data in that range of the file,
298 * and that the new data won't completely replace the old data in
299 * that range of the file.
300 */
301static bool nfs_folio_is_full_write(struct folio *folio, loff_t pos,
302 unsigned int len)
303{
304 unsigned int pglen = nfs_folio_length(folio);
305 unsigned int offset = offset_in_folio(folio, pos);
306 unsigned int end = offset + len;
307
308 return !pglen || (end >= pglen && !offset);
309}
310
311static bool nfs_want_read_modify_write(struct file *file, struct folio *folio,
312 loff_t pos, unsigned int len)
313{
314 /*
315 * Up-to-date pages, those with ongoing or full-page write
316 * don't need read/modify/write
317 */
318 if (folio_test_uptodate(folio) || folio_test_private(folio) ||
319 nfs_folio_is_full_write(folio, pos, len))
320 return false;
321
322 if (pnfs_ld_read_whole_page(file_inode(file)))
323 return true;
324 /* Open for reading too? */
325 if (file->f_mode & FMODE_READ)
326 return true;
327 return false;
328}
329
330/*
331 * This does the "real" work of the write. We must allocate and lock the
332 * page to be sent back to the generic routine, which then copies the
333 * data from user space.
334 *
335 * If the writer ends up delaying the write, the writer needs to
336 * increment the page use counts until he is done with the page.
337 */
338static int nfs_write_begin(struct file *file, struct address_space *mapping,
339 loff_t pos, unsigned len, struct page **pagep,
340 void **fsdata)
341{
342 struct folio *folio;
343 int once_thru = 0;
344 int ret;
345
346 dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
347 file, mapping->host->i_ino, len, (long long) pos);
348
349start:
350 folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, FGP_WRITEBEGIN,
351 mapping_gfp_mask(mapping));
352 if (IS_ERR(folio))
353 return PTR_ERR(folio);
354 *pagep = &folio->page;
355
356 ret = nfs_flush_incompatible(file, folio);
357 if (ret) {
358 folio_unlock(folio);
359 folio_put(folio);
360 } else if (!once_thru &&
361 nfs_want_read_modify_write(file, folio, pos, len)) {
362 once_thru = 1;
363 ret = nfs_read_folio(file, folio);
364 folio_put(folio);
365 if (!ret)
366 goto start;
367 }
368 return ret;
369}
370
371static int nfs_write_end(struct file *file, struct address_space *mapping,
372 loff_t pos, unsigned len, unsigned copied,
373 struct page *page, void *fsdata)
374{
375 struct nfs_open_context *ctx = nfs_file_open_context(file);
376 struct folio *folio = page_folio(page);
377 unsigned offset = offset_in_folio(folio, pos);
378 int status;
379
380 dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
381 file, mapping->host->i_ino, len, (long long) pos);
382
383 /*
384 * Zero any uninitialised parts of the page, and then mark the page
385 * as up to date if it turns out that we're extending the file.
386 */
387 if (!folio_test_uptodate(folio)) {
388 size_t fsize = folio_size(folio);
389 unsigned pglen = nfs_folio_length(folio);
390 unsigned end = offset + copied;
391
392 if (pglen == 0) {
393 folio_zero_segments(folio, 0, offset, end, fsize);
394 folio_mark_uptodate(folio);
395 } else if (end >= pglen) {
396 folio_zero_segment(folio, end, fsize);
397 if (offset == 0)
398 folio_mark_uptodate(folio);
399 } else
400 folio_zero_segment(folio, pglen, fsize);
401 }
402
403 status = nfs_update_folio(file, folio, offset, copied);
404
405 folio_unlock(folio);
406 folio_put(folio);
407
408 if (status < 0)
409 return status;
410 NFS_I(mapping->host)->write_io += copied;
411
412 if (nfs_ctx_key_to_expire(ctx, mapping->host))
413 nfs_wb_all(mapping->host);
414
415 return copied;
416}
417
418/*
419 * Partially or wholly invalidate a page
420 * - Release the private state associated with a page if undergoing complete
421 * page invalidation
422 * - Called if either PG_private or PG_fscache is set on the page
423 * - Caller holds page lock
424 */
425static void nfs_invalidate_folio(struct folio *folio, size_t offset,
426 size_t length)
427{
428 struct inode *inode = folio_file_mapping(folio)->host;
429 dfprintk(PAGECACHE, "NFS: invalidate_folio(%lu, %zu, %zu)\n",
430 folio->index, offset, length);
431
432 if (offset != 0 || length < folio_size(folio))
433 return;
434 /* Cancel any unstarted writes on this page */
435 nfs_wb_folio_cancel(inode, folio);
436 folio_wait_fscache(folio);
437 trace_nfs_invalidate_folio(inode, folio);
438}
439
440/*
441 * Attempt to release the private state associated with a folio
442 * - Called if either private or fscache flags are set on the folio
443 * - Caller holds folio lock
444 * - Return true (may release folio) or false (may not)
445 */
446static bool nfs_release_folio(struct folio *folio, gfp_t gfp)
447{
448 dfprintk(PAGECACHE, "NFS: release_folio(%p)\n", folio);
449
450 /* If the private flag is set, then the folio is not freeable */
451 if (folio_test_private(folio)) {
452 if ((current_gfp_context(gfp) & GFP_KERNEL) != GFP_KERNEL ||
453 current_is_kswapd())
454 return false;
455 if (nfs_wb_folio(folio_file_mapping(folio)->host, folio) < 0)
456 return false;
457 }
458 return nfs_fscache_release_folio(folio, gfp);
459}
460
461static void nfs_check_dirty_writeback(struct folio *folio,
462 bool *dirty, bool *writeback)
463{
464 struct nfs_inode *nfsi;
465 struct address_space *mapping = folio->mapping;
466
467 /*
468 * Check if an unstable folio is currently being committed and
469 * if so, have the VM treat it as if the folio is under writeback
470 * so it will not block due to folios that will shortly be freeable.
471 */
472 nfsi = NFS_I(mapping->host);
473 if (atomic_read(&nfsi->commit_info.rpcs_out)) {
474 *writeback = true;
475 return;
476 }
477
478 /*
479 * If the private flag is set, then the folio is not freeable
480 * and as the inode is not being committed, it's not going to
481 * be cleaned in the near future so treat it as dirty
482 */
483 if (folio_test_private(folio))
484 *dirty = true;
485}
486
487/*
488 * Attempt to clear the private state associated with a page when an error
489 * occurs that requires the cached contents of an inode to be written back or
490 * destroyed
491 * - Called if either PG_private or fscache is set on the page
492 * - Caller holds page lock
493 * - Return 0 if successful, -error otherwise
494 */
495static int nfs_launder_folio(struct folio *folio)
496{
497 struct inode *inode = folio->mapping->host;
498 int ret;
499
500 dfprintk(PAGECACHE, "NFS: launder_folio(%ld, %llu)\n",
501 inode->i_ino, folio_pos(folio));
502
503 folio_wait_fscache(folio);
504 ret = nfs_wb_folio(inode, folio);
505 trace_nfs_launder_folio_done(inode, folio, ret);
506 return ret;
507}
508
509static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
510 sector_t *span)
511{
512 unsigned long blocks;
513 long long isize;
514 int ret;
515 struct inode *inode = file_inode(file);
516 struct rpc_clnt *clnt = NFS_CLIENT(inode);
517 struct nfs_client *cl = NFS_SERVER(inode)->nfs_client;
518
519 spin_lock(&inode->i_lock);
520 blocks = inode->i_blocks;
521 isize = inode->i_size;
522 spin_unlock(&inode->i_lock);
523 if (blocks*512 < isize) {
524 pr_warn("swap activate: swapfile has holes\n");
525 return -EINVAL;
526 }
527
528 ret = rpc_clnt_swap_activate(clnt);
529 if (ret)
530 return ret;
531 ret = add_swap_extent(sis, 0, sis->max, 0);
532 if (ret < 0) {
533 rpc_clnt_swap_deactivate(clnt);
534 return ret;
535 }
536
537 *span = sis->pages;
538
539 if (cl->rpc_ops->enable_swap)
540 cl->rpc_ops->enable_swap(inode);
541
542 sis->flags |= SWP_FS_OPS;
543 return ret;
544}
545
546static void nfs_swap_deactivate(struct file *file)
547{
548 struct inode *inode = file_inode(file);
549 struct rpc_clnt *clnt = NFS_CLIENT(inode);
550 struct nfs_client *cl = NFS_SERVER(inode)->nfs_client;
551
552 rpc_clnt_swap_deactivate(clnt);
553 if (cl->rpc_ops->disable_swap)
554 cl->rpc_ops->disable_swap(file_inode(file));
555}
556
557const struct address_space_operations nfs_file_aops = {
558 .read_folio = nfs_read_folio,
559 .readahead = nfs_readahead,
560 .dirty_folio = filemap_dirty_folio,
561 .writepages = nfs_writepages,
562 .write_begin = nfs_write_begin,
563 .write_end = nfs_write_end,
564 .invalidate_folio = nfs_invalidate_folio,
565 .release_folio = nfs_release_folio,
566 .migrate_folio = nfs_migrate_folio,
567 .launder_folio = nfs_launder_folio,
568 .is_dirty_writeback = nfs_check_dirty_writeback,
569 .error_remove_folio = generic_error_remove_folio,
570 .swap_activate = nfs_swap_activate,
571 .swap_deactivate = nfs_swap_deactivate,
572 .swap_rw = nfs_swap_rw,
573};
574
575/*
576 * Notification that a PTE pointing to an NFS page is about to be made
577 * writable, implying that someone is about to modify the page through a
578 * shared-writable mapping
579 */
580static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf)
581{
582 struct file *filp = vmf->vma->vm_file;
583 struct inode *inode = file_inode(filp);
584 unsigned pagelen;
585 vm_fault_t ret = VM_FAULT_NOPAGE;
586 struct address_space *mapping;
587 struct folio *folio = page_folio(vmf->page);
588
589 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
590 filp, filp->f_mapping->host->i_ino,
591 (long long)folio_file_pos(folio));
592
593 sb_start_pagefault(inode->i_sb);
594
595 /* make sure the cache has finished storing the page */
596 if (folio_test_fscache(folio) &&
597 folio_wait_fscache_killable(folio) < 0) {
598 ret = VM_FAULT_RETRY;
599 goto out;
600 }
601
602 wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
603 nfs_wait_bit_killable,
604 TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
605
606 folio_lock(folio);
607 mapping = folio_file_mapping(folio);
608 if (mapping != inode->i_mapping)
609 goto out_unlock;
610
611 folio_wait_writeback(folio);
612
613 pagelen = nfs_folio_length(folio);
614 if (pagelen == 0)
615 goto out_unlock;
616
617 ret = VM_FAULT_LOCKED;
618 if (nfs_flush_incompatible(filp, folio) == 0 &&
619 nfs_update_folio(filp, folio, 0, pagelen) == 0)
620 goto out;
621
622 ret = VM_FAULT_SIGBUS;
623out_unlock:
624 folio_unlock(folio);
625out:
626 sb_end_pagefault(inode->i_sb);
627 return ret;
628}
629
630static const struct vm_operations_struct nfs_file_vm_ops = {
631 .fault = filemap_fault,
632 .map_pages = filemap_map_pages,
633 .page_mkwrite = nfs_vm_page_mkwrite,
634};
635
636ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
637{
638 struct file *file = iocb->ki_filp;
639 struct inode *inode = file_inode(file);
640 unsigned int mntflags = NFS_SERVER(inode)->flags;
641 ssize_t result, written;
642 errseq_t since;
643 int error;
644
645 result = nfs_key_timeout_notify(file, inode);
646 if (result)
647 return result;
648
649 if (iocb->ki_flags & IOCB_DIRECT)
650 return nfs_file_direct_write(iocb, from, false);
651
652 dprintk("NFS: write(%pD2, %zu@%Ld)\n",
653 file, iov_iter_count(from), (long long) iocb->ki_pos);
654
655 if (IS_SWAPFILE(inode))
656 goto out_swapfile;
657 /*
658 * O_APPEND implies that we must revalidate the file length.
659 */
660 if (iocb->ki_flags & IOCB_APPEND || iocb->ki_pos > i_size_read(inode)) {
661 result = nfs_revalidate_file_size(inode, file);
662 if (result)
663 return result;
664 }
665
666 nfs_clear_invalid_mapping(file->f_mapping);
667
668 since = filemap_sample_wb_err(file->f_mapping);
669 nfs_start_io_write(inode);
670 result = generic_write_checks(iocb, from);
671 if (result > 0)
672 result = generic_perform_write(iocb, from);
673 nfs_end_io_write(inode);
674 if (result <= 0)
675 goto out;
676
677 written = result;
678 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
679
680 if (mntflags & NFS_MOUNT_WRITE_EAGER) {
681 result = filemap_fdatawrite_range(file->f_mapping,
682 iocb->ki_pos - written,
683 iocb->ki_pos - 1);
684 if (result < 0)
685 goto out;
686 }
687 if (mntflags & NFS_MOUNT_WRITE_WAIT) {
688 filemap_fdatawait_range(file->f_mapping,
689 iocb->ki_pos - written,
690 iocb->ki_pos - 1);
691 }
692 result = generic_write_sync(iocb, written);
693 if (result < 0)
694 return result;
695
696out:
697 /* Return error values */
698 error = filemap_check_wb_err(file->f_mapping, since);
699 switch (error) {
700 default:
701 break;
702 case -EDQUOT:
703 case -EFBIG:
704 case -ENOSPC:
705 nfs_wb_all(inode);
706 error = file_check_and_advance_wb_err(file);
707 if (error < 0)
708 result = error;
709 }
710 return result;
711
712out_swapfile:
713 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
714 return -ETXTBSY;
715}
716EXPORT_SYMBOL_GPL(nfs_file_write);
717
718static int
719do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
720{
721 struct inode *inode = filp->f_mapping->host;
722 int status = 0;
723 unsigned int saved_type = fl->fl_type;
724
725 /* Try local locking first */
726 posix_test_lock(filp, fl);
727 if (fl->fl_type != F_UNLCK) {
728 /* found a conflict */
729 goto out;
730 }
731 fl->fl_type = saved_type;
732
733 if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
734 goto out_noconflict;
735
736 if (is_local)
737 goto out_noconflict;
738
739 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
740out:
741 return status;
742out_noconflict:
743 fl->fl_type = F_UNLCK;
744 goto out;
745}
746
747static int
748do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
749{
750 struct inode *inode = filp->f_mapping->host;
751 struct nfs_lock_context *l_ctx;
752 int status;
753
754 /*
755 * Flush all pending writes before doing anything
756 * with locks..
757 */
758 nfs_wb_all(inode);
759
760 l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
761 if (!IS_ERR(l_ctx)) {
762 status = nfs_iocounter_wait(l_ctx);
763 nfs_put_lock_context(l_ctx);
764 /* NOTE: special case
765 * If we're signalled while cleaning up locks on process exit, we
766 * still need to complete the unlock.
767 */
768 if (status < 0 && !(fl->fl_flags & FL_CLOSE))
769 return status;
770 }
771
772 /*
773 * Use local locking if mounted with "-onolock" or with appropriate
774 * "-olocal_lock="
775 */
776 if (!is_local)
777 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
778 else
779 status = locks_lock_file_wait(filp, fl);
780 return status;
781}
782
783static int
784do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
785{
786 struct inode *inode = filp->f_mapping->host;
787 int status;
788
789 /*
790 * Flush all pending writes before doing anything
791 * with locks..
792 */
793 status = nfs_sync_mapping(filp->f_mapping);
794 if (status != 0)
795 goto out;
796
797 /*
798 * Use local locking if mounted with "-onolock" or with appropriate
799 * "-olocal_lock="
800 */
801 if (!is_local)
802 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
803 else
804 status = locks_lock_file_wait(filp, fl);
805 if (status < 0)
806 goto out;
807
808 /*
809 * Invalidate cache to prevent missing any changes. If
810 * the file is mapped, clear the page cache as well so
811 * those mappings will be loaded.
812 *
813 * This makes locking act as a cache coherency point.
814 */
815 nfs_sync_mapping(filp->f_mapping);
816 if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) {
817 nfs_zap_caches(inode);
818 if (mapping_mapped(filp->f_mapping))
819 nfs_revalidate_mapping(inode, filp->f_mapping);
820 }
821out:
822 return status;
823}
824
825/*
826 * Lock a (portion of) a file
827 */
828int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
829{
830 struct inode *inode = filp->f_mapping->host;
831 int ret = -ENOLCK;
832 int is_local = 0;
833
834 dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n",
835 filp, fl->fl_type, fl->fl_flags,
836 (long long)fl->fl_start, (long long)fl->fl_end);
837
838 nfs_inc_stats(inode, NFSIOS_VFSLOCK);
839
840 if (fl->fl_flags & FL_RECLAIM)
841 return -ENOGRACE;
842
843 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
844 is_local = 1;
845
846 if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
847 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
848 if (ret < 0)
849 goto out_err;
850 }
851
852 if (IS_GETLK(cmd))
853 ret = do_getlk(filp, cmd, fl, is_local);
854 else if (fl->fl_type == F_UNLCK)
855 ret = do_unlk(filp, cmd, fl, is_local);
856 else
857 ret = do_setlk(filp, cmd, fl, is_local);
858out_err:
859 return ret;
860}
861EXPORT_SYMBOL_GPL(nfs_lock);
862
863/*
864 * Lock a (portion of) a file
865 */
866int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
867{
868 struct inode *inode = filp->f_mapping->host;
869 int is_local = 0;
870
871 dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n",
872 filp, fl->fl_type, fl->fl_flags);
873
874 if (!(fl->fl_flags & FL_FLOCK))
875 return -ENOLCK;
876
877 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
878 is_local = 1;
879
880 /* We're simulating flock() locks using posix locks on the server */
881 if (fl->fl_type == F_UNLCK)
882 return do_unlk(filp, cmd, fl, is_local);
883 return do_setlk(filp, cmd, fl, is_local);
884}
885EXPORT_SYMBOL_GPL(nfs_flock);
886
887const struct file_operations nfs_file_operations = {
888 .llseek = nfs_file_llseek,
889 .read_iter = nfs_file_read,
890 .write_iter = nfs_file_write,
891 .mmap = nfs_file_mmap,
892 .open = nfs_file_open,
893 .flush = nfs_file_flush,
894 .release = nfs_file_release,
895 .fsync = nfs_file_fsync,
896 .lock = nfs_lock,
897 .flock = nfs_flock,
898 .splice_read = nfs_file_splice_read,
899 .splice_write = iter_file_splice_write,
900 .check_flags = nfs_check_flags,
901 .setlease = simple_nosetlease,
902};
903EXPORT_SYMBOL_GPL(nfs_file_operations);
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/gfp.h>
30#include <linux/swap.h>
31
32#include <asm/uaccess.h>
33
34#include "delegation.h"
35#include "internal.h"
36#include "iostat.h"
37#include "fscache.h"
38#include "pnfs.h"
39
40#include "nfstrace.h"
41
42#define NFSDBG_FACILITY NFSDBG_FILE
43
44static const struct vm_operations_struct nfs_file_vm_ops;
45
46/* Hack for future NFS swap support */
47#ifndef IS_SWAPFILE
48# define IS_SWAPFILE(inode) (0)
49#endif
50
51int nfs_check_flags(int flags)
52{
53 if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
54 return -EINVAL;
55
56 return 0;
57}
58EXPORT_SYMBOL_GPL(nfs_check_flags);
59
60/*
61 * Open file
62 */
63static int
64nfs_file_open(struct inode *inode, struct file *filp)
65{
66 int res;
67
68 dprintk("NFS: open file(%pD2)\n", filp);
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
79int
80nfs_file_release(struct inode *inode, struct file *filp)
81{
82 dprintk("NFS: release(%pD2)\n", filp);
83
84 nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
85 nfs_file_clear_open_context(filp);
86 return 0;
87}
88EXPORT_SYMBOL_GPL(nfs_file_release);
89
90/**
91 * nfs_revalidate_size - Revalidate the file size
92 * @inode - pointer to inode struct
93 * @file - pointer to struct file
94 *
95 * Revalidates the file length. This is basically a wrapper around
96 * nfs_revalidate_inode() that takes into account the fact that we may
97 * have cached writes (in which case we don't care about the server's
98 * idea of what the file length is), or O_DIRECT (in which case we
99 * shouldn't trust the cache).
100 */
101static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
102{
103 struct nfs_server *server = NFS_SERVER(inode);
104 struct nfs_inode *nfsi = NFS_I(inode);
105
106 if (nfs_have_delegated_attributes(inode))
107 goto out_noreval;
108
109 if (filp->f_flags & O_DIRECT)
110 goto force_reval;
111 if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
112 goto force_reval;
113 if (nfs_attribute_timeout(inode))
114 goto force_reval;
115out_noreval:
116 return 0;
117force_reval:
118 return __nfs_revalidate_inode(server, inode);
119}
120
121loff_t nfs_file_llseek(struct file *filp, loff_t offset, int whence)
122{
123 dprintk("NFS: llseek file(%pD2, %lld, %d)\n",
124 filp, offset, whence);
125
126 /*
127 * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
128 * the cached file length
129 */
130 if (whence != SEEK_SET && whence != SEEK_CUR) {
131 struct inode *inode = filp->f_mapping->host;
132
133 int retval = nfs_revalidate_file_size(inode, filp);
134 if (retval < 0)
135 return (loff_t)retval;
136 }
137
138 return generic_file_llseek(filp, offset, whence);
139}
140EXPORT_SYMBOL_GPL(nfs_file_llseek);
141
142/*
143 * Flush all dirty pages, and check for write errors.
144 */
145static int
146nfs_file_flush(struct file *file, fl_owner_t id)
147{
148 struct inode *inode = file_inode(file);
149
150 dprintk("NFS: flush(%pD2)\n", file);
151
152 nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
153 if ((file->f_mode & FMODE_WRITE) == 0)
154 return 0;
155
156 /* Flush writes to the server and return any errors */
157 return vfs_fsync(file, 0);
158}
159
160ssize_t
161nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
162{
163 struct inode *inode = file_inode(iocb->ki_filp);
164 ssize_t result;
165
166 if (iocb->ki_flags & IOCB_DIRECT)
167 return nfs_file_direct_read(iocb, to, iocb->ki_pos);
168
169 dprintk("NFS: read(%pD2, %zu@%lu)\n",
170 iocb->ki_filp,
171 iov_iter_count(to), (unsigned long) iocb->ki_pos);
172
173 result = nfs_revalidate_mapping_protected(inode, iocb->ki_filp->f_mapping);
174 if (!result) {
175 result = generic_file_read_iter(iocb, to);
176 if (result > 0)
177 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
178 }
179 return result;
180}
181EXPORT_SYMBOL_GPL(nfs_file_read);
182
183ssize_t
184nfs_file_splice_read(struct file *filp, loff_t *ppos,
185 struct pipe_inode_info *pipe, size_t count,
186 unsigned int flags)
187{
188 struct inode *inode = file_inode(filp);
189 ssize_t res;
190
191 dprintk("NFS: splice_read(%pD2, %lu@%Lu)\n",
192 filp, (unsigned long) count, (unsigned long long) *ppos);
193
194 res = nfs_revalidate_mapping_protected(inode, filp->f_mapping);
195 if (!res) {
196 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
197 if (res > 0)
198 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, res);
199 }
200 return res;
201}
202EXPORT_SYMBOL_GPL(nfs_file_splice_read);
203
204int
205nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
206{
207 struct inode *inode = file_inode(file);
208 int status;
209
210 dprintk("NFS: mmap(%pD2)\n", file);
211
212 /* Note: generic_file_mmap() returns ENOSYS on nommu systems
213 * so we call that before revalidating the mapping
214 */
215 status = generic_file_mmap(file, vma);
216 if (!status) {
217 vma->vm_ops = &nfs_file_vm_ops;
218 status = nfs_revalidate_mapping(inode, file->f_mapping);
219 }
220 return status;
221}
222EXPORT_SYMBOL_GPL(nfs_file_mmap);
223
224/*
225 * Flush any dirty pages for this process, and check for write errors.
226 * The return status from this call provides a reliable indication of
227 * whether any write errors occurred for this process.
228 *
229 * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
230 * disk, but it retrieves and clears ctx->error after synching, despite
231 * the two being set at the same time in nfs_context_set_write_error().
232 * This is because the former is used to notify the _next_ call to
233 * nfs_file_write() that a write error occurred, and hence cause it to
234 * fall back to doing a synchronous write.
235 */
236static int
237nfs_file_fsync_commit(struct file *file, loff_t start, loff_t end, int datasync)
238{
239 struct nfs_open_context *ctx = nfs_file_open_context(file);
240 struct inode *inode = file_inode(file);
241 int have_error, do_resend, status;
242 int ret = 0;
243
244 dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
245
246 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
247 do_resend = test_and_clear_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
248 have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
249 status = nfs_commit_inode(inode, FLUSH_SYNC);
250 have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
251 if (have_error) {
252 ret = xchg(&ctx->error, 0);
253 if (ret)
254 goto out;
255 }
256 if (status < 0) {
257 ret = status;
258 goto out;
259 }
260 do_resend |= test_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
261 if (do_resend)
262 ret = -EAGAIN;
263out:
264 return ret;
265}
266
267int
268nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
269{
270 int ret;
271 struct inode *inode = file_inode(file);
272
273 trace_nfs_fsync_enter(inode);
274
275 inode_dio_wait(inode);
276 do {
277 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
278 if (ret != 0)
279 break;
280 inode_lock(inode);
281 ret = nfs_file_fsync_commit(file, start, end, datasync);
282 if (!ret)
283 ret = pnfs_sync_inode(inode, !!datasync);
284 inode_unlock(inode);
285 /*
286 * If nfs_file_fsync_commit detected a server reboot, then
287 * resend all dirty pages that might have been covered by
288 * the NFS_CONTEXT_RESEND_WRITES flag
289 */
290 start = 0;
291 end = LLONG_MAX;
292 } while (ret == -EAGAIN);
293
294 trace_nfs_fsync_exit(inode, ret);
295 return ret;
296}
297EXPORT_SYMBOL_GPL(nfs_file_fsync);
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 */
319static 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_SIZE - 1);
324 unsigned int end = offset + len;
325
326 if (pnfs_ld_read_whole_page(file->f_mapping->host)) {
327 if (!PageUptodate(page))
328 return 1;
329 return 0;
330 }
331
332 if ((file->f_mode & FMODE_READ) && /* open for read? */
333 !PageUptodate(page) && /* Uptodate? */
334 !PagePrivate(page) && /* i/o request already? */
335 pglen && /* valid bytes of file? */
336 (end < pglen || offset)) /* replace all valid bytes? */
337 return 1;
338 return 0;
339}
340
341/*
342 * This does the "real" work of the write. We must allocate and lock the
343 * page to be sent back to the generic routine, which then copies the
344 * data from user space.
345 *
346 * If the writer ends up delaying the write, the writer needs to
347 * increment the page use counts until he is done with the page.
348 */
349static int nfs_write_begin(struct file *file, struct address_space *mapping,
350 loff_t pos, unsigned len, unsigned flags,
351 struct page **pagep, void **fsdata)
352{
353 int ret;
354 pgoff_t index = pos >> PAGE_SHIFT;
355 struct page *page;
356 int once_thru = 0;
357
358 dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
359 file, mapping->host->i_ino, len, (long long) pos);
360
361start:
362 /*
363 * Prevent starvation issues if someone is doing a consistency
364 * sync-to-disk
365 */
366 ret = wait_on_bit_action(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
367 nfs_wait_bit_killable, TASK_KILLABLE);
368 if (ret)
369 return ret;
370 /*
371 * Wait for O_DIRECT to complete
372 */
373 inode_dio_wait(mapping->host);
374
375 page = grab_cache_page_write_begin(mapping, index, flags);
376 if (!page)
377 return -ENOMEM;
378 *pagep = page;
379
380 ret = nfs_flush_incompatible(file, page);
381 if (ret) {
382 unlock_page(page);
383 put_page(page);
384 } else if (!once_thru &&
385 nfs_want_read_modify_write(file, page, pos, len)) {
386 once_thru = 1;
387 ret = nfs_readpage(file, page);
388 put_page(page);
389 if (!ret)
390 goto start;
391 }
392 return ret;
393}
394
395static int nfs_write_end(struct file *file, struct address_space *mapping,
396 loff_t pos, unsigned len, unsigned copied,
397 struct page *page, void *fsdata)
398{
399 unsigned offset = pos & (PAGE_SIZE - 1);
400 struct nfs_open_context *ctx = nfs_file_open_context(file);
401 int status;
402
403 dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
404 file, mapping->host->i_ino, len, (long long) pos);
405
406 /*
407 * Zero any uninitialised parts of the page, and then mark the page
408 * as up to date if it turns out that we're extending the file.
409 */
410 if (!PageUptodate(page)) {
411 unsigned pglen = nfs_page_length(page);
412 unsigned end = offset + len;
413
414 if (pglen == 0) {
415 zero_user_segments(page, 0, offset,
416 end, PAGE_SIZE);
417 SetPageUptodate(page);
418 } else if (end >= pglen) {
419 zero_user_segment(page, end, PAGE_SIZE);
420 if (offset == 0)
421 SetPageUptodate(page);
422 } else
423 zero_user_segment(page, pglen, PAGE_SIZE);
424 }
425
426 status = nfs_updatepage(file, page, offset, copied);
427
428 unlock_page(page);
429 put_page(page);
430
431 if (status < 0)
432 return status;
433 NFS_I(mapping->host)->write_io += copied;
434
435 if (nfs_ctx_key_to_expire(ctx)) {
436 status = nfs_wb_all(mapping->host);
437 if (status < 0)
438 return status;
439 }
440
441 return copied;
442}
443
444/*
445 * Partially or wholly invalidate a page
446 * - Release the private state associated with a page if undergoing complete
447 * page invalidation
448 * - Called if either PG_private or PG_fscache is set on the page
449 * - Caller holds page lock
450 */
451static void nfs_invalidate_page(struct page *page, unsigned int offset,
452 unsigned int length)
453{
454 dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %u, %u)\n",
455 page, offset, length);
456
457 if (offset != 0 || length < PAGE_SIZE)
458 return;
459 /* Cancel any unstarted writes on this page */
460 nfs_wb_page_cancel(page_file_mapping(page)->host, page);
461
462 nfs_fscache_invalidate_page(page, page->mapping->host);
463}
464
465/*
466 * Attempt to release the private state associated with a page
467 * - Called if either PG_private or PG_fscache is set on the page
468 * - Caller holds page lock
469 * - Return true (may release page) or false (may not)
470 */
471static int nfs_release_page(struct page *page, gfp_t gfp)
472{
473 struct address_space *mapping = page->mapping;
474
475 dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
476
477 /* Always try to initiate a 'commit' if relevant, but only
478 * wait for it if the caller allows blocking. Even then,
479 * only wait 1 second and only if the 'bdi' is not congested.
480 * Waiting indefinitely can cause deadlocks when the NFS
481 * server is on this machine, when a new TCP connection is
482 * needed and in other rare cases. There is no particular
483 * need to wait extensively here. A short wait has the
484 * benefit that someone else can worry about the freezer.
485 */
486 if (mapping) {
487 struct nfs_server *nfss = NFS_SERVER(mapping->host);
488 nfs_commit_inode(mapping->host, 0);
489 if (gfpflags_allow_blocking(gfp) &&
490 !bdi_write_congested(&nfss->backing_dev_info)) {
491 wait_on_page_bit_killable_timeout(page, PG_private,
492 HZ);
493 if (PagePrivate(page))
494 set_bdi_congested(&nfss->backing_dev_info,
495 BLK_RW_ASYNC);
496 }
497 }
498 /* If PagePrivate() is set, then the page is not freeable */
499 if (PagePrivate(page))
500 return 0;
501 return nfs_fscache_release_page(page, gfp);
502}
503
504static void nfs_check_dirty_writeback(struct page *page,
505 bool *dirty, bool *writeback)
506{
507 struct nfs_inode *nfsi;
508 struct address_space *mapping = page_file_mapping(page);
509
510 if (!mapping || PageSwapCache(page))
511 return;
512
513 /*
514 * Check if an unstable page is currently being committed and
515 * if so, have the VM treat it as if the page is under writeback
516 * so it will not block due to pages that will shortly be freeable.
517 */
518 nfsi = NFS_I(mapping->host);
519 if (atomic_read(&nfsi->commit_info.rpcs_out)) {
520 *writeback = true;
521 return;
522 }
523
524 /*
525 * If PagePrivate() is set, then the page is not freeable and as the
526 * inode is not being committed, it's not going to be cleaned in the
527 * near future so treat it as dirty
528 */
529 if (PagePrivate(page))
530 *dirty = true;
531}
532
533/*
534 * Attempt to clear the private state associated with a page when an error
535 * occurs that requires the cached contents of an inode to be written back or
536 * destroyed
537 * - Called if either PG_private or fscache is set on the page
538 * - Caller holds page lock
539 * - Return 0 if successful, -error otherwise
540 */
541static int nfs_launder_page(struct page *page)
542{
543 struct inode *inode = page_file_mapping(page)->host;
544 struct nfs_inode *nfsi = NFS_I(inode);
545
546 dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
547 inode->i_ino, (long long)page_offset(page));
548
549 nfs_fscache_wait_on_page_write(nfsi, page);
550 return nfs_wb_launder_page(inode, page);
551}
552
553static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
554 sector_t *span)
555{
556 struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
557
558 *span = sis->pages;
559
560 return rpc_clnt_swap_activate(clnt);
561}
562
563static void nfs_swap_deactivate(struct file *file)
564{
565 struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
566
567 rpc_clnt_swap_deactivate(clnt);
568}
569
570const struct address_space_operations nfs_file_aops = {
571 .readpage = nfs_readpage,
572 .readpages = nfs_readpages,
573 .set_page_dirty = __set_page_dirty_nobuffers,
574 .writepage = nfs_writepage,
575 .writepages = nfs_writepages,
576 .write_begin = nfs_write_begin,
577 .write_end = nfs_write_end,
578 .invalidatepage = nfs_invalidate_page,
579 .releasepage = nfs_release_page,
580 .direct_IO = nfs_direct_IO,
581 .migratepage = nfs_migrate_page,
582 .launder_page = nfs_launder_page,
583 .is_dirty_writeback = nfs_check_dirty_writeback,
584 .error_remove_page = generic_error_remove_page,
585 .swap_activate = nfs_swap_activate,
586 .swap_deactivate = nfs_swap_deactivate,
587};
588
589/*
590 * Notification that a PTE pointing to an NFS page is about to be made
591 * writable, implying that someone is about to modify the page through a
592 * shared-writable mapping
593 */
594static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
595{
596 struct page *page = vmf->page;
597 struct file *filp = vma->vm_file;
598 struct inode *inode = file_inode(filp);
599 unsigned pagelen;
600 int ret = VM_FAULT_NOPAGE;
601 struct address_space *mapping;
602
603 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
604 filp, filp->f_mapping->host->i_ino,
605 (long long)page_offset(page));
606
607 /* make sure the cache has finished storing the page */
608 nfs_fscache_wait_on_page_write(NFS_I(inode), page);
609
610 wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
611 nfs_wait_bit_killable, TASK_KILLABLE);
612
613 lock_page(page);
614 mapping = page_file_mapping(page);
615 if (mapping != inode->i_mapping)
616 goto out_unlock;
617
618 wait_on_page_writeback(page);
619
620 pagelen = nfs_page_length(page);
621 if (pagelen == 0)
622 goto out_unlock;
623
624 ret = VM_FAULT_LOCKED;
625 if (nfs_flush_incompatible(filp, page) == 0 &&
626 nfs_updatepage(filp, page, 0, pagelen) == 0)
627 goto out;
628
629 ret = VM_FAULT_SIGBUS;
630out_unlock:
631 unlock_page(page);
632out:
633 return ret;
634}
635
636static const struct vm_operations_struct nfs_file_vm_ops = {
637 .fault = filemap_fault,
638 .map_pages = filemap_map_pages,
639 .page_mkwrite = nfs_vm_page_mkwrite,
640};
641
642static int nfs_need_check_write(struct file *filp, struct inode *inode)
643{
644 struct nfs_open_context *ctx;
645
646 ctx = nfs_file_open_context(filp);
647 if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags) ||
648 nfs_ctx_key_to_expire(ctx))
649 return 1;
650 return 0;
651}
652
653ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
654{
655 struct file *file = iocb->ki_filp;
656 struct inode *inode = file_inode(file);
657 unsigned long written = 0;
658 ssize_t result;
659 size_t count = iov_iter_count(from);
660
661 result = nfs_key_timeout_notify(file, inode);
662 if (result)
663 return result;
664
665 if (iocb->ki_flags & IOCB_DIRECT) {
666 result = generic_write_checks(iocb, from);
667 if (result <= 0)
668 return result;
669 return nfs_file_direct_write(iocb, from);
670 }
671
672 dprintk("NFS: write(%pD2, %zu@%Ld)\n",
673 file, count, (long long) iocb->ki_pos);
674
675 result = -EBUSY;
676 if (IS_SWAPFILE(inode))
677 goto out_swapfile;
678 /*
679 * O_APPEND implies that we must revalidate the file length.
680 */
681 if (iocb->ki_flags & IOCB_APPEND) {
682 result = nfs_revalidate_file_size(inode, file);
683 if (result)
684 goto out;
685 }
686
687 result = count;
688 if (!count)
689 goto out;
690
691 result = generic_file_write_iter(iocb, from);
692 if (result > 0)
693 written = result;
694
695 /* Return error values */
696 if (result >= 0 && nfs_need_check_write(file, inode)) {
697 int err = vfs_fsync(file, 0);
698 if (err < 0)
699 result = err;
700 }
701 if (result > 0)
702 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
703out:
704 return result;
705
706out_swapfile:
707 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
708 goto out;
709}
710EXPORT_SYMBOL_GPL(nfs_file_write);
711
712static int
713do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
714{
715 struct inode *inode = filp->f_mapping->host;
716 int status = 0;
717 unsigned int saved_type = fl->fl_type;
718
719 /* Try local locking first */
720 posix_test_lock(filp, fl);
721 if (fl->fl_type != F_UNLCK) {
722 /* found a conflict */
723 goto out;
724 }
725 fl->fl_type = saved_type;
726
727 if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
728 goto out_noconflict;
729
730 if (is_local)
731 goto out_noconflict;
732
733 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
734out:
735 return status;
736out_noconflict:
737 fl->fl_type = F_UNLCK;
738 goto out;
739}
740
741static int do_vfs_lock(struct file *file, struct file_lock *fl)
742{
743 return locks_lock_file_wait(file, fl);
744}
745
746static int
747do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
748{
749 struct inode *inode = filp->f_mapping->host;
750 struct nfs_lock_context *l_ctx;
751 int status;
752
753 /*
754 * Flush all pending writes before doing anything
755 * with locks..
756 */
757 vfs_fsync(filp, 0);
758
759 l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
760 if (!IS_ERR(l_ctx)) {
761 status = nfs_iocounter_wait(l_ctx);
762 nfs_put_lock_context(l_ctx);
763 if (status < 0)
764 return status;
765 }
766
767 /* NOTE: special case
768 * If we're signalled while cleaning up locks on process exit, we
769 * still need to complete the unlock.
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 return status;
780}
781
782static int
783is_time_granular(struct timespec *ts) {
784 return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000));
785}
786
787static int
788do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
789{
790 struct inode *inode = filp->f_mapping->host;
791 int status;
792
793 /*
794 * Flush all pending writes before doing anything
795 * with locks..
796 */
797 status = nfs_sync_mapping(filp->f_mapping);
798 if (status != 0)
799 goto out;
800
801 /*
802 * Use local locking if mounted with "-onolock" or with appropriate
803 * "-olocal_lock="
804 */
805 if (!is_local)
806 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
807 else
808 status = do_vfs_lock(filp, fl);
809 if (status < 0)
810 goto out;
811
812 /*
813 * Revalidate the cache if the server has time stamps granular
814 * enough to detect subsecond changes. Otherwise, clear the
815 * cache to prevent missing any changes.
816 *
817 * This makes locking act as a cache coherency point.
818 */
819 nfs_sync_mapping(filp->f_mapping);
820 if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) {
821 if (is_time_granular(&NFS_SERVER(inode)->time_delta))
822 __nfs_revalidate_inode(NFS_SERVER(inode), inode);
823 else
824 nfs_zap_caches(inode);
825 }
826out:
827 return status;
828}
829
830/*
831 * Lock a (portion of) a file
832 */
833int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
834{
835 struct inode *inode = filp->f_mapping->host;
836 int ret = -ENOLCK;
837 int is_local = 0;
838
839 dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n",
840 filp, fl->fl_type, fl->fl_flags,
841 (long long)fl->fl_start, (long long)fl->fl_end);
842
843 nfs_inc_stats(inode, NFSIOS_VFSLOCK);
844
845 /* No mandatory locks over NFS */
846 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
847 goto out_err;
848
849 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
850 is_local = 1;
851
852 if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
853 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
854 if (ret < 0)
855 goto out_err;
856 }
857
858 if (IS_GETLK(cmd))
859 ret = do_getlk(filp, cmd, fl, is_local);
860 else if (fl->fl_type == F_UNLCK)
861 ret = do_unlk(filp, cmd, fl, is_local);
862 else
863 ret = do_setlk(filp, cmd, fl, is_local);
864out_err:
865 return ret;
866}
867EXPORT_SYMBOL_GPL(nfs_lock);
868
869/*
870 * Lock a (portion of) a file
871 */
872int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
873{
874 struct inode *inode = filp->f_mapping->host;
875 int is_local = 0;
876
877 dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n",
878 filp, fl->fl_type, fl->fl_flags);
879
880 if (!(fl->fl_flags & FL_FLOCK))
881 return -ENOLCK;
882
883 /*
884 * The NFSv4 protocol doesn't support LOCK_MAND, which is not part of
885 * any standard. In principle we might be able to support LOCK_MAND
886 * on NFSv2/3 since NLMv3/4 support DOS share modes, but for now the
887 * NFS code is not set up for it.
888 */
889 if (fl->fl_type & LOCK_MAND)
890 return -EINVAL;
891
892 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
893 is_local = 1;
894
895 /* We're simulating flock() locks using posix locks on the server */
896 if (fl->fl_type == F_UNLCK)
897 return do_unlk(filp, cmd, fl, is_local);
898 return do_setlk(filp, cmd, fl, is_local);
899}
900EXPORT_SYMBOL_GPL(nfs_flock);
901
902const struct file_operations nfs_file_operations = {
903 .llseek = nfs_file_llseek,
904 .read_iter = nfs_file_read,
905 .write_iter = nfs_file_write,
906 .mmap = nfs_file_mmap,
907 .open = nfs_file_open,
908 .flush = nfs_file_flush,
909 .release = nfs_file_release,
910 .fsync = nfs_file_fsync,
911 .lock = nfs_lock,
912 .flock = nfs_flock,
913 .splice_read = nfs_file_splice_read,
914 .splice_write = iter_file_splice_write,
915 .check_flags = nfs_check_flags,
916 .setlease = simple_nosetlease,
917};
918EXPORT_SYMBOL_GPL(nfs_file_operations);