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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
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
45static const struct vm_operations_struct nfs_file_vm_ops;
46
47/* Hack for future NFS swap support */
48#ifndef IS_SWAPFILE
49# define IS_SWAPFILE(inode) (0)
50#endif
51
52int nfs_check_flags(int flags)
53{
54 if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
55 return -EINVAL;
56
57 return 0;
58}
59EXPORT_SYMBOL_GPL(nfs_check_flags);
60
61/*
62 * Open file
63 */
64static int
65nfs_file_open(struct inode *inode, struct file *filp)
66{
67 int res;
68
69 dprintk("NFS: open file(%pD2)\n", filp);
70
71 nfs_inc_stats(inode, NFSIOS_VFSOPEN);
72 res = nfs_check_flags(filp->f_flags);
73 if (res)
74 return res;
75
76 res = nfs_open(inode, filp);
77 return res;
78}
79
80int
81nfs_file_release(struct inode *inode, struct file *filp)
82{
83 dprintk("NFS: release(%pD2)\n", filp);
84
85 nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
86 nfs_file_clear_open_context(filp);
87 return 0;
88}
89EXPORT_SYMBOL_GPL(nfs_file_release);
90
91/**
92 * nfs_revalidate_size - Revalidate the file size
93 * @inode: pointer to inode struct
94 * @filp: 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 */
102static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
103{
104 struct nfs_server *server = NFS_SERVER(inode);
105
106 if (filp->f_flags & O_DIRECT)
107 goto force_reval;
108 if (nfs_check_cache_invalid(inode, NFS_INO_REVAL_PAGECACHE))
109 goto force_reval;
110 return 0;
111force_reval:
112 return __nfs_revalidate_inode(server, inode);
113}
114
115loff_t nfs_file_llseek(struct file *filp, loff_t offset, int whence)
116{
117 dprintk("NFS: llseek file(%pD2, %lld, %d)\n",
118 filp, offset, whence);
119
120 /*
121 * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
122 * the cached file length
123 */
124 if (whence != SEEK_SET && whence != SEEK_CUR) {
125 struct inode *inode = filp->f_mapping->host;
126
127 int retval = nfs_revalidate_file_size(inode, filp);
128 if (retval < 0)
129 return (loff_t)retval;
130 }
131
132 return generic_file_llseek(filp, offset, whence);
133}
134EXPORT_SYMBOL_GPL(nfs_file_llseek);
135
136/*
137 * Flush all dirty pages, and check for write errors.
138 */
139static int
140nfs_file_flush(struct file *file, fl_owner_t id)
141{
142 struct inode *inode = file_inode(file);
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 return nfs_wb_all(inode);
152}
153
154ssize_t
155nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
156{
157 struct inode *inode = file_inode(iocb->ki_filp);
158 ssize_t result;
159
160 if (iocb->ki_flags & IOCB_DIRECT)
161 return nfs_file_direct_read(iocb, to);
162
163 dprintk("NFS: read(%pD2, %zu@%lu)\n",
164 iocb->ki_filp,
165 iov_iter_count(to), (unsigned long) iocb->ki_pos);
166
167 nfs_start_io_read(inode);
168 result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
169 if (!result) {
170 result = generic_file_read_iter(iocb, to);
171 if (result > 0)
172 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
173 }
174 nfs_end_io_read(inode);
175 return result;
176}
177EXPORT_SYMBOL_GPL(nfs_file_read);
178
179int
180nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
181{
182 struct inode *inode = file_inode(file);
183 int status;
184
185 dprintk("NFS: mmap(%pD2)\n", file);
186
187 /* Note: generic_file_mmap() returns ENOSYS on nommu systems
188 * so we call that before revalidating the mapping
189 */
190 status = generic_file_mmap(file, vma);
191 if (!status) {
192 vma->vm_ops = &nfs_file_vm_ops;
193 status = nfs_revalidate_mapping(inode, file->f_mapping);
194 }
195 return status;
196}
197EXPORT_SYMBOL_GPL(nfs_file_mmap);
198
199/*
200 * Flush any dirty pages for this process, and check for write errors.
201 * The return status from this call provides a reliable indication of
202 * whether any write errors occurred for this process.
203 */
204static int
205nfs_file_fsync_commit(struct file *file, int datasync)
206{
207 struct nfs_open_context *ctx = nfs_file_open_context(file);
208 struct inode *inode = file_inode(file);
209 int do_resend, status;
210 int ret = 0;
211
212 dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
213
214 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
215 do_resend = test_and_clear_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
216 status = nfs_commit_inode(inode, FLUSH_SYNC);
217 if (status == 0)
218 status = file_check_and_advance_wb_err(file);
219 if (status < 0) {
220 ret = status;
221 goto out;
222 }
223 do_resend |= test_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
224 if (do_resend)
225 ret = -EAGAIN;
226out:
227 return ret;
228}
229
230int
231nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
232{
233 int ret;
234 struct inode *inode = file_inode(file);
235
236 trace_nfs_fsync_enter(inode);
237
238 do {
239 ret = file_write_and_wait_range(file, start, end);
240 if (ret != 0)
241 break;
242 ret = nfs_file_fsync_commit(file, datasync);
243 if (!ret)
244 ret = pnfs_sync_inode(inode, !!datasync);
245 /*
246 * If nfs_file_fsync_commit detected a server reboot, then
247 * resend all dirty pages that might have been covered by
248 * the NFS_CONTEXT_RESEND_WRITES flag
249 */
250 start = 0;
251 end = LLONG_MAX;
252 } while (ret == -EAGAIN);
253
254 trace_nfs_fsync_exit(inode, ret);
255 return ret;
256}
257EXPORT_SYMBOL_GPL(nfs_file_fsync);
258
259/*
260 * Decide whether a read/modify/write cycle may be more efficient
261 * then a modify/write/read cycle when writing to a page in the
262 * page cache.
263 *
264 * Some pNFS layout drivers can only read/write at a certain block
265 * granularity like all block devices and therefore we must perform
266 * read/modify/write whenever a page hasn't read yet and the data
267 * to be written there is not aligned to a block boundary and/or
268 * smaller than the block size.
269 *
270 * The modify/write/read cycle may occur if a page is read before
271 * being completely filled by the writer. In this situation, the
272 * page must be completely written to stable storage on the server
273 * before it can be refilled by reading in the page from the server.
274 * This can lead to expensive, small, FILE_SYNC mode writes being
275 * done.
276 *
277 * It may be more efficient to read the page first if the file is
278 * open for reading in addition to writing, the page is not marked
279 * as Uptodate, it is not dirty or waiting to be committed,
280 * indicating that it was previously allocated and then modified,
281 * that there were valid bytes of data in that range of the file,
282 * and that the new data won't completely replace the old data in
283 * that range of the file.
284 */
285static bool nfs_full_page_write(struct page *page, loff_t pos, unsigned int len)
286{
287 unsigned int pglen = nfs_page_length(page);
288 unsigned int offset = pos & (PAGE_SIZE - 1);
289 unsigned int end = offset + len;
290
291 return !pglen || (end >= pglen && !offset);
292}
293
294static bool nfs_want_read_modify_write(struct file *file, struct page *page,
295 loff_t pos, unsigned int len)
296{
297 /*
298 * Up-to-date pages, those with ongoing or full-page write
299 * don't need read/modify/write
300 */
301 if (PageUptodate(page) || PagePrivate(page) ||
302 nfs_full_page_write(page, pos, len))
303 return false;
304
305 if (pnfs_ld_read_whole_page(file->f_mapping->host))
306 return true;
307 /* Open for reading too? */
308 if (file->f_mode & FMODE_READ)
309 return true;
310 return false;
311}
312
313/*
314 * This does the "real" work of the write. We must allocate and lock the
315 * page to be sent back to the generic routine, which then copies the
316 * data from user space.
317 *
318 * If the writer ends up delaying the write, the writer needs to
319 * increment the page use counts until he is done with the page.
320 */
321static int nfs_write_begin(struct file *file, struct address_space *mapping,
322 loff_t pos, unsigned len, unsigned flags,
323 struct page **pagep, void **fsdata)
324{
325 int ret;
326 pgoff_t index = pos >> PAGE_SHIFT;
327 struct page *page;
328 int once_thru = 0;
329
330 dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
331 file, mapping->host->i_ino, len, (long long) pos);
332
333start:
334 page = grab_cache_page_write_begin(mapping, index, flags);
335 if (!page)
336 return -ENOMEM;
337 *pagep = page;
338
339 ret = nfs_flush_incompatible(file, page);
340 if (ret) {
341 unlock_page(page);
342 put_page(page);
343 } else if (!once_thru &&
344 nfs_want_read_modify_write(file, page, pos, len)) {
345 once_thru = 1;
346 ret = nfs_readpage(file, page);
347 put_page(page);
348 if (!ret)
349 goto start;
350 }
351 return ret;
352}
353
354static int nfs_write_end(struct file *file, struct address_space *mapping,
355 loff_t pos, unsigned len, unsigned copied,
356 struct page *page, void *fsdata)
357{
358 unsigned offset = pos & (PAGE_SIZE - 1);
359 struct nfs_open_context *ctx = nfs_file_open_context(file);
360 int status;
361
362 dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
363 file, mapping->host->i_ino, len, (long long) pos);
364
365 /*
366 * Zero any uninitialised parts of the page, and then mark the page
367 * as up to date if it turns out that we're extending the file.
368 */
369 if (!PageUptodate(page)) {
370 unsigned pglen = nfs_page_length(page);
371 unsigned end = offset + copied;
372
373 if (pglen == 0) {
374 zero_user_segments(page, 0, offset,
375 end, PAGE_SIZE);
376 SetPageUptodate(page);
377 } else if (end >= pglen) {
378 zero_user_segment(page, end, PAGE_SIZE);
379 if (offset == 0)
380 SetPageUptodate(page);
381 } else
382 zero_user_segment(page, pglen, PAGE_SIZE);
383 }
384
385 status = nfs_updatepage(file, page, offset, copied);
386
387 unlock_page(page);
388 put_page(page);
389
390 if (status < 0)
391 return status;
392 NFS_I(mapping->host)->write_io += copied;
393
394 if (nfs_ctx_key_to_expire(ctx, mapping->host)) {
395 status = nfs_wb_all(mapping->host);
396 if (status < 0)
397 return status;
398 }
399
400 return copied;
401}
402
403/*
404 * Partially or wholly invalidate a page
405 * - Release the private state associated with a page if undergoing complete
406 * page invalidation
407 * - Called if either PG_private or PG_fscache is set on the page
408 * - Caller holds page lock
409 */
410static void nfs_invalidate_page(struct page *page, unsigned int offset,
411 unsigned int length)
412{
413 dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %u, %u)\n",
414 page, offset, length);
415
416 if (offset != 0 || length < PAGE_SIZE)
417 return;
418 /* Cancel any unstarted writes on this page */
419 nfs_wb_page_cancel(page_file_mapping(page)->host, page);
420
421 nfs_fscache_invalidate_page(page, page->mapping->host);
422}
423
424/*
425 * Attempt to release the private state associated with a page
426 * - Called if either PG_private or PG_fscache is set on the page
427 * - Caller holds page lock
428 * - Return true (may release page) or false (may not)
429 */
430static int nfs_release_page(struct page *page, gfp_t gfp)
431{
432 dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
433
434 /* If PagePrivate() is set, then the page is not freeable */
435 if (PagePrivate(page))
436 return 0;
437 return nfs_fscache_release_page(page, gfp);
438}
439
440static void nfs_check_dirty_writeback(struct page *page,
441 bool *dirty, bool *writeback)
442{
443 struct nfs_inode *nfsi;
444 struct address_space *mapping = page_file_mapping(page);
445
446 if (!mapping || PageSwapCache(page))
447 return;
448
449 /*
450 * Check if an unstable page is currently being committed and
451 * if so, have the VM treat it as if the page is under writeback
452 * so it will not block due to pages that will shortly be freeable.
453 */
454 nfsi = NFS_I(mapping->host);
455 if (atomic_read(&nfsi->commit_info.rpcs_out)) {
456 *writeback = true;
457 return;
458 }
459
460 /*
461 * If PagePrivate() is set, then the page is not freeable and as the
462 * inode is not being committed, it's not going to be cleaned in the
463 * near future so treat it as dirty
464 */
465 if (PagePrivate(page))
466 *dirty = true;
467}
468
469/*
470 * Attempt to clear the private state associated with a page when an error
471 * occurs that requires the cached contents of an inode to be written back or
472 * destroyed
473 * - Called if either PG_private or fscache is set on the page
474 * - Caller holds page lock
475 * - Return 0 if successful, -error otherwise
476 */
477static int nfs_launder_page(struct page *page)
478{
479 struct inode *inode = page_file_mapping(page)->host;
480 struct nfs_inode *nfsi = NFS_I(inode);
481
482 dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
483 inode->i_ino, (long long)page_offset(page));
484
485 nfs_fscache_wait_on_page_write(nfsi, page);
486 return nfs_wb_page(inode, page);
487}
488
489static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
490 sector_t *span)
491{
492 struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
493
494 *span = sis->pages;
495
496 return rpc_clnt_swap_activate(clnt);
497}
498
499static void nfs_swap_deactivate(struct file *file)
500{
501 struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
502
503 rpc_clnt_swap_deactivate(clnt);
504}
505
506const struct address_space_operations nfs_file_aops = {
507 .readpage = nfs_readpage,
508 .readpages = nfs_readpages,
509 .set_page_dirty = __set_page_dirty_nobuffers,
510 .writepage = nfs_writepage,
511 .writepages = nfs_writepages,
512 .write_begin = nfs_write_begin,
513 .write_end = nfs_write_end,
514 .invalidatepage = nfs_invalidate_page,
515 .releasepage = nfs_release_page,
516 .direct_IO = nfs_direct_IO,
517#ifdef CONFIG_MIGRATION
518 .migratepage = nfs_migrate_page,
519#endif
520 .launder_page = nfs_launder_page,
521 .is_dirty_writeback = nfs_check_dirty_writeback,
522 .error_remove_page = generic_error_remove_page,
523 .swap_activate = nfs_swap_activate,
524 .swap_deactivate = nfs_swap_deactivate,
525};
526
527/*
528 * Notification that a PTE pointing to an NFS page is about to be made
529 * writable, implying that someone is about to modify the page through a
530 * shared-writable mapping
531 */
532static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf)
533{
534 struct page *page = vmf->page;
535 struct file *filp = vmf->vma->vm_file;
536 struct inode *inode = file_inode(filp);
537 unsigned pagelen;
538 vm_fault_t ret = VM_FAULT_NOPAGE;
539 struct address_space *mapping;
540
541 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
542 filp, filp->f_mapping->host->i_ino,
543 (long long)page_offset(page));
544
545 sb_start_pagefault(inode->i_sb);
546
547 /* make sure the cache has finished storing the page */
548 nfs_fscache_wait_on_page_write(NFS_I(inode), page);
549
550 wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
551 nfs_wait_bit_killable, TASK_KILLABLE);
552
553 lock_page(page);
554 mapping = page_file_mapping(page);
555 if (mapping != inode->i_mapping)
556 goto out_unlock;
557
558 wait_on_page_writeback(page);
559
560 pagelen = nfs_page_length(page);
561 if (pagelen == 0)
562 goto out_unlock;
563
564 ret = VM_FAULT_LOCKED;
565 if (nfs_flush_incompatible(filp, page) == 0 &&
566 nfs_updatepage(filp, page, 0, pagelen) == 0)
567 goto out;
568
569 ret = VM_FAULT_SIGBUS;
570out_unlock:
571 unlock_page(page);
572out:
573 sb_end_pagefault(inode->i_sb);
574 return ret;
575}
576
577static const struct vm_operations_struct nfs_file_vm_ops = {
578 .fault = filemap_fault,
579 .map_pages = filemap_map_pages,
580 .page_mkwrite = nfs_vm_page_mkwrite,
581};
582
583static int nfs_need_check_write(struct file *filp, struct inode *inode)
584{
585 struct nfs_open_context *ctx;
586
587 ctx = nfs_file_open_context(filp);
588 if (nfs_ctx_key_to_expire(ctx, inode))
589 return 1;
590 return 0;
591}
592
593ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
594{
595 struct file *file = iocb->ki_filp;
596 struct inode *inode = file_inode(file);
597 unsigned long written = 0;
598 ssize_t result;
599
600 result = nfs_key_timeout_notify(file, inode);
601 if (result)
602 return result;
603
604 if (iocb->ki_flags & IOCB_DIRECT)
605 return nfs_file_direct_write(iocb, from);
606
607 dprintk("NFS: write(%pD2, %zu@%Ld)\n",
608 file, iov_iter_count(from), (long long) iocb->ki_pos);
609
610 if (IS_SWAPFILE(inode))
611 goto out_swapfile;
612 /*
613 * O_APPEND implies that we must revalidate the file length.
614 */
615 if (iocb->ki_flags & IOCB_APPEND) {
616 result = nfs_revalidate_file_size(inode, file);
617 if (result)
618 goto out;
619 }
620 if (iocb->ki_pos > i_size_read(inode))
621 nfs_revalidate_mapping(inode, file->f_mapping);
622
623 nfs_start_io_write(inode);
624 result = generic_write_checks(iocb, from);
625 if (result > 0) {
626 current->backing_dev_info = inode_to_bdi(inode);
627 result = generic_perform_write(file, from, iocb->ki_pos);
628 current->backing_dev_info = NULL;
629 }
630 nfs_end_io_write(inode);
631 if (result <= 0)
632 goto out;
633
634 written = result;
635 iocb->ki_pos += written;
636 result = generic_write_sync(iocb, written);
637 if (result < 0)
638 goto out;
639
640 /* Return error values */
641 if (nfs_need_check_write(file, inode)) {
642 int err = nfs_wb_all(inode);
643 if (err < 0)
644 result = err;
645 }
646 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
647out:
648 return result;
649
650out_swapfile:
651 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
652 return -EBUSY;
653}
654EXPORT_SYMBOL_GPL(nfs_file_write);
655
656static int
657do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
658{
659 struct inode *inode = filp->f_mapping->host;
660 int status = 0;
661 unsigned int saved_type = fl->fl_type;
662
663 /* Try local locking first */
664 posix_test_lock(filp, fl);
665 if (fl->fl_type != F_UNLCK) {
666 /* found a conflict */
667 goto out;
668 }
669 fl->fl_type = saved_type;
670
671 if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
672 goto out_noconflict;
673
674 if (is_local)
675 goto out_noconflict;
676
677 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
678out:
679 return status;
680out_noconflict:
681 fl->fl_type = F_UNLCK;
682 goto out;
683}
684
685static int
686do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
687{
688 struct inode *inode = filp->f_mapping->host;
689 struct nfs_lock_context *l_ctx;
690 int status;
691
692 /*
693 * Flush all pending writes before doing anything
694 * with locks..
695 */
696 nfs_wb_all(inode);
697
698 l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
699 if (!IS_ERR(l_ctx)) {
700 status = nfs_iocounter_wait(l_ctx);
701 nfs_put_lock_context(l_ctx);
702 /* NOTE: special case
703 * If we're signalled while cleaning up locks on process exit, we
704 * still need to complete the unlock.
705 */
706 if (status < 0 && !(fl->fl_flags & FL_CLOSE))
707 return status;
708 }
709
710 /*
711 * Use local locking if mounted with "-onolock" or with appropriate
712 * "-olocal_lock="
713 */
714 if (!is_local)
715 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
716 else
717 status = locks_lock_file_wait(filp, fl);
718 return status;
719}
720
721static int
722do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
723{
724 struct inode *inode = filp->f_mapping->host;
725 int status;
726
727 /*
728 * Flush all pending writes before doing anything
729 * with locks..
730 */
731 status = nfs_sync_mapping(filp->f_mapping);
732 if (status != 0)
733 goto out;
734
735 /*
736 * Use local locking if mounted with "-onolock" or with appropriate
737 * "-olocal_lock="
738 */
739 if (!is_local)
740 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
741 else
742 status = locks_lock_file_wait(filp, fl);
743 if (status < 0)
744 goto out;
745
746 /*
747 * Invalidate cache to prevent missing any changes. If
748 * the file is mapped, clear the page cache as well so
749 * those mappings will be loaded.
750 *
751 * This makes locking act as a cache coherency point.
752 */
753 nfs_sync_mapping(filp->f_mapping);
754 if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) {
755 nfs_zap_caches(inode);
756 if (mapping_mapped(filp->f_mapping))
757 nfs_revalidate_mapping(inode, filp->f_mapping);
758 }
759out:
760 return status;
761}
762
763/*
764 * Lock a (portion of) a file
765 */
766int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
767{
768 struct inode *inode = filp->f_mapping->host;
769 int ret = -ENOLCK;
770 int is_local = 0;
771
772 dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n",
773 filp, fl->fl_type, fl->fl_flags,
774 (long long)fl->fl_start, (long long)fl->fl_end);
775
776 nfs_inc_stats(inode, NFSIOS_VFSLOCK);
777
778 /* No mandatory locks over NFS */
779 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
780 goto out_err;
781
782 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
783 is_local = 1;
784
785 if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
786 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
787 if (ret < 0)
788 goto out_err;
789 }
790
791 if (IS_GETLK(cmd))
792 ret = do_getlk(filp, cmd, fl, is_local);
793 else if (fl->fl_type == F_UNLCK)
794 ret = do_unlk(filp, cmd, fl, is_local);
795 else
796 ret = do_setlk(filp, cmd, fl, is_local);
797out_err:
798 return ret;
799}
800EXPORT_SYMBOL_GPL(nfs_lock);
801
802/*
803 * Lock a (portion of) a file
804 */
805int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
806{
807 struct inode *inode = filp->f_mapping->host;
808 int is_local = 0;
809
810 dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n",
811 filp, fl->fl_type, fl->fl_flags);
812
813 if (!(fl->fl_flags & FL_FLOCK))
814 return -ENOLCK;
815
816 /*
817 * The NFSv4 protocol doesn't support LOCK_MAND, which is not part of
818 * any standard. In principle we might be able to support LOCK_MAND
819 * on NFSv2/3 since NLMv3/4 support DOS share modes, but for now the
820 * NFS code is not set up for it.
821 */
822 if (fl->fl_type & LOCK_MAND)
823 return -EINVAL;
824
825 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
826 is_local = 1;
827
828 /* We're simulating flock() locks using posix locks on the server */
829 if (fl->fl_type == F_UNLCK)
830 return do_unlk(filp, cmd, fl, is_local);
831 return do_setlk(filp, cmd, fl, is_local);
832}
833EXPORT_SYMBOL_GPL(nfs_flock);
834
835const struct file_operations nfs_file_operations = {
836 .llseek = nfs_file_llseek,
837 .read_iter = nfs_file_read,
838 .write_iter = nfs_file_write,
839 .mmap = nfs_file_mmap,
840 .open = nfs_file_open,
841 .flush = nfs_file_flush,
842 .release = nfs_file_release,
843 .fsync = nfs_file_fsync,
844 .lock = nfs_lock,
845 .flock = nfs_flock,
846 .splice_read = generic_file_splice_read,
847 .splice_write = iter_file_splice_write,
848 .check_flags = nfs_check_flags,
849 .setlease = simple_nosetlease,
850};
851EXPORT_SYMBOL_GPL(nfs_file_operations);
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#include <linux/compaction.h>
33
34#include <linux/uaccess.h>
35#include <linux/filelock.h>
36
37#include "delegation.h"
38#include "internal.h"
39#include "iostat.h"
40#include "fscache.h"
41#include "pnfs.h"
42
43#include "nfstrace.h"
44
45#define NFSDBG_FACILITY NFSDBG_FILE
46
47static const struct vm_operations_struct nfs_file_vm_ops;
48
49int 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}
56EXPORT_SYMBOL_GPL(nfs_check_flags);
57
58/*
59 * Open file
60 */
61static int
62nfs_file_open(struct inode *inode, struct file *filp)
63{
64 int res;
65
66 dprintk("NFS: open file(%pD2)\n", filp);
67
68 nfs_inc_stats(inode, NFSIOS_VFSOPEN);
69 res = nfs_check_flags(filp->f_flags);
70 if (res)
71 return res;
72
73 res = nfs_open(inode, filp);
74 if (res == 0)
75 filp->f_mode |= FMODE_CAN_ODIRECT;
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 nfs_fscache_release_file(inode, filp);
87 return 0;
88}
89EXPORT_SYMBOL_GPL(nfs_file_release);
90
91/**
92 * nfs_revalidate_file_size - Revalidate the file size
93 * @inode: pointer to inode struct
94 * @filp: 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 */
102static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
103{
104 struct nfs_server *server = NFS_SERVER(inode);
105
106 if (filp->f_flags & O_DIRECT)
107 goto force_reval;
108 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_SIZE))
109 goto force_reval;
110 return 0;
111force_reval:
112 return __nfs_revalidate_inode(server, inode);
113}
114
115loff_t nfs_file_llseek(struct file *filp, loff_t offset, int whence)
116{
117 dprintk("NFS: llseek file(%pD2, %lld, %d)\n",
118 filp, offset, whence);
119
120 /*
121 * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
122 * the cached file length
123 */
124 if (whence != SEEK_SET && whence != SEEK_CUR) {
125 struct inode *inode = filp->f_mapping->host;
126
127 int retval = nfs_revalidate_file_size(inode, filp);
128 if (retval < 0)
129 return (loff_t)retval;
130 }
131
132 return generic_file_llseek(filp, offset, whence);
133}
134EXPORT_SYMBOL_GPL(nfs_file_llseek);
135
136/*
137 * Flush all dirty pages, and check for write errors.
138 */
139static int
140nfs_file_flush(struct file *file, fl_owner_t id)
141{
142 struct inode *inode = file_inode(file);
143 errseq_t since;
144
145 dprintk("NFS: flush(%pD2)\n", file);
146
147 nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
148 if ((file->f_mode & FMODE_WRITE) == 0)
149 return 0;
150
151 /* Flush writes to the server and return any errors */
152 since = filemap_sample_wb_err(file->f_mapping);
153 nfs_wb_all(inode);
154 return filemap_check_wb_err(file->f_mapping, since);
155}
156
157ssize_t
158nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
159{
160 struct inode *inode = file_inode(iocb->ki_filp);
161 ssize_t result;
162
163 if (iocb->ki_flags & IOCB_DIRECT)
164 return nfs_file_direct_read(iocb, to, false);
165
166 dprintk("NFS: read(%pD2, %zu@%lu)\n",
167 iocb->ki_filp,
168 iov_iter_count(to), (unsigned long) iocb->ki_pos);
169
170 result = nfs_start_io_read(inode);
171 if (result)
172 return result;
173
174 result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
175 if (!result) {
176 result = generic_file_read_iter(iocb, to);
177 if (result > 0)
178 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
179 }
180 nfs_end_io_read(inode);
181 return result;
182}
183EXPORT_SYMBOL_GPL(nfs_file_read);
184
185ssize_t
186nfs_file_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe,
187 size_t len, unsigned int flags)
188{
189 struct inode *inode = file_inode(in);
190 ssize_t result;
191
192 dprintk("NFS: splice_read(%pD2, %zu@%llu)\n", in, len, *ppos);
193
194 result = nfs_start_io_read(inode);
195 if (result)
196 return result;
197
198 result = nfs_revalidate_mapping(inode, in->f_mapping);
199 if (!result) {
200 result = filemap_splice_read(in, ppos, pipe, len, flags);
201 if (result > 0)
202 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
203 }
204 nfs_end_io_read(inode);
205 return result;
206}
207EXPORT_SYMBOL_GPL(nfs_file_splice_read);
208
209int
210nfs_file_mmap(struct file *file, struct vm_area_struct *vma)
211{
212 struct inode *inode = file_inode(file);
213 int status;
214
215 dprintk("NFS: mmap(%pD2)\n", file);
216
217 /* Note: generic_file_mmap() returns ENOSYS on nommu systems
218 * so we call that before revalidating the mapping
219 */
220 status = generic_file_mmap(file, vma);
221 if (!status) {
222 vma->vm_ops = &nfs_file_vm_ops;
223 status = nfs_revalidate_mapping(inode, file->f_mapping);
224 }
225 return status;
226}
227EXPORT_SYMBOL_GPL(nfs_file_mmap);
228
229/*
230 * Flush any dirty pages for this process, and check for write errors.
231 * The return status from this call provides a reliable indication of
232 * whether any write errors occurred for this process.
233 */
234static int
235nfs_file_fsync_commit(struct file *file, int datasync)
236{
237 struct inode *inode = file_inode(file);
238 int ret, ret2;
239
240 dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
241
242 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
243 ret = nfs_commit_inode(inode, FLUSH_SYNC);
244 ret2 = file_check_and_advance_wb_err(file);
245 if (ret2 < 0)
246 return ret2;
247 return ret;
248}
249
250int
251nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
252{
253 struct inode *inode = file_inode(file);
254 struct nfs_inode *nfsi = NFS_I(inode);
255 long save_nredirtied = atomic_long_read(&nfsi->redirtied_pages);
256 long nredirtied;
257 int ret;
258
259 trace_nfs_fsync_enter(inode);
260
261 for (;;) {
262 ret = file_write_and_wait_range(file, start, end);
263 if (ret != 0)
264 break;
265 ret = nfs_file_fsync_commit(file, datasync);
266 if (ret != 0)
267 break;
268 ret = pnfs_sync_inode(inode, !!datasync);
269 if (ret != 0)
270 break;
271 nredirtied = atomic_long_read(&nfsi->redirtied_pages);
272 if (nredirtied == save_nredirtied)
273 break;
274 save_nredirtied = nredirtied;
275 }
276
277 trace_nfs_fsync_exit(inode, ret);
278 return ret;
279}
280EXPORT_SYMBOL_GPL(nfs_file_fsync);
281
282/*
283 * Decide whether a read/modify/write cycle may be more efficient
284 * then a modify/write/read cycle when writing to a page in the
285 * page cache.
286 *
287 * Some pNFS layout drivers can only read/write at a certain block
288 * granularity like all block devices and therefore we must perform
289 * read/modify/write whenever a page hasn't read yet and the data
290 * to be written there is not aligned to a block boundary and/or
291 * smaller than the block size.
292 *
293 * The modify/write/read cycle may occur if a page is read before
294 * being completely filled by the writer. In this situation, the
295 * page must be completely written to stable storage on the server
296 * before it can be refilled by reading in the page from the server.
297 * This can lead to expensive, small, FILE_SYNC mode writes being
298 * done.
299 *
300 * It may be more efficient to read the page first if the file is
301 * open for reading in addition to writing, the page is not marked
302 * as Uptodate, it is not dirty or waiting to be committed,
303 * indicating that it was previously allocated and then modified,
304 * that there were valid bytes of data in that range of the file,
305 * and that the new data won't completely replace the old data in
306 * that range of the file.
307 */
308static bool nfs_folio_is_full_write(struct folio *folio, loff_t pos,
309 unsigned int len)
310{
311 unsigned int pglen = nfs_folio_length(folio);
312 unsigned int offset = offset_in_folio(folio, pos);
313 unsigned int end = offset + len;
314
315 return !pglen || (end >= pglen && !offset);
316}
317
318static bool nfs_want_read_modify_write(struct file *file, struct folio *folio,
319 loff_t pos, unsigned int len)
320{
321 /*
322 * Up-to-date pages, those with ongoing or full-page write
323 * don't need read/modify/write
324 */
325 if (folio_test_uptodate(folio) || folio_test_private(folio) ||
326 nfs_folio_is_full_write(folio, pos, len))
327 return false;
328
329 if (pnfs_ld_read_whole_page(file_inode(file)))
330 return true;
331 /* Open for reading too? */
332 if (file->f_mode & FMODE_READ)
333 return true;
334 return false;
335}
336
337/*
338 * This does the "real" work of the write. We must allocate and lock the
339 * page to be sent back to the generic routine, which then copies the
340 * data from user space.
341 *
342 * If the writer ends up delaying the write, the writer needs to
343 * increment the page use counts until he is done with the page.
344 */
345static int nfs_write_begin(struct file *file, struct address_space *mapping,
346 loff_t pos, unsigned len, struct folio **foliop,
347 void **fsdata)
348{
349 fgf_t fgp = FGP_WRITEBEGIN;
350 struct folio *folio;
351 int once_thru = 0;
352 int ret;
353
354 dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
355 file, mapping->host->i_ino, len, (long long) pos);
356
357 fgp |= fgf_set_order(len);
358start:
359 folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, fgp,
360 mapping_gfp_mask(mapping));
361 if (IS_ERR(folio))
362 return PTR_ERR(folio);
363 *foliop = folio;
364
365 ret = nfs_flush_incompatible(file, folio);
366 if (ret) {
367 folio_unlock(folio);
368 folio_put(folio);
369 } else if (!once_thru &&
370 nfs_want_read_modify_write(file, folio, pos, len)) {
371 once_thru = 1;
372 ret = nfs_read_folio(file, folio);
373 folio_put(folio);
374 if (!ret)
375 goto start;
376 }
377 return ret;
378}
379
380static int nfs_write_end(struct file *file, struct address_space *mapping,
381 loff_t pos, unsigned len, unsigned copied,
382 struct folio *folio, void *fsdata)
383{
384 struct nfs_open_context *ctx = nfs_file_open_context(file);
385 unsigned offset = offset_in_folio(folio, pos);
386 int status;
387
388 dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
389 file, mapping->host->i_ino, len, (long long) pos);
390
391 /*
392 * Zero any uninitialised parts of the page, and then mark the page
393 * as up to date if it turns out that we're extending the file.
394 */
395 if (!folio_test_uptodate(folio)) {
396 size_t fsize = folio_size(folio);
397 unsigned pglen = nfs_folio_length(folio);
398 unsigned end = offset + copied;
399
400 if (pglen == 0) {
401 folio_zero_segments(folio, 0, offset, end, fsize);
402 folio_mark_uptodate(folio);
403 } else if (end >= pglen) {
404 folio_zero_segment(folio, end, fsize);
405 if (offset == 0)
406 folio_mark_uptodate(folio);
407 } else
408 folio_zero_segment(folio, pglen, fsize);
409 }
410
411 status = nfs_update_folio(file, folio, offset, copied);
412
413 folio_unlock(folio);
414 folio_put(folio);
415
416 if (status < 0)
417 return status;
418 NFS_I(mapping->host)->write_io += copied;
419
420 if (nfs_ctx_key_to_expire(ctx, mapping->host))
421 nfs_wb_all(mapping->host);
422
423 return copied;
424}
425
426/*
427 * Partially or wholly invalidate a page
428 * - Release the private state associated with a page if undergoing complete
429 * page invalidation
430 * - Called if either PG_private or PG_fscache is set on the page
431 * - Caller holds page lock
432 */
433static void nfs_invalidate_folio(struct folio *folio, size_t offset,
434 size_t length)
435{
436 struct inode *inode = folio->mapping->host;
437 dfprintk(PAGECACHE, "NFS: invalidate_folio(%lu, %zu, %zu)\n",
438 folio->index, offset, length);
439
440 if (offset != 0 || length < folio_size(folio))
441 return;
442 /* Cancel any unstarted writes on this page */
443 nfs_wb_folio_cancel(inode, folio);
444 folio_wait_private_2(folio); /* [DEPRECATED] */
445 trace_nfs_invalidate_folio(inode, folio_pos(folio) + offset, length);
446}
447
448/*
449 * Attempt to release the private state associated with a folio
450 * - Called if either private or fscache flags are set on the folio
451 * - Caller holds folio lock
452 * - Return true (may release folio) or false (may not)
453 */
454static bool nfs_release_folio(struct folio *folio, gfp_t gfp)
455{
456 dfprintk(PAGECACHE, "NFS: release_folio(%p)\n", folio);
457
458 /* If the private flag is set, then the folio is not freeable */
459 if (folio_test_private(folio)) {
460 if ((current_gfp_context(gfp) & GFP_KERNEL) != GFP_KERNEL ||
461 current_is_kswapd() || current_is_kcompactd())
462 return false;
463 if (nfs_wb_folio(folio->mapping->host, folio) < 0)
464 return false;
465 }
466 return nfs_fscache_release_folio(folio, gfp);
467}
468
469static void nfs_check_dirty_writeback(struct folio *folio,
470 bool *dirty, bool *writeback)
471{
472 struct nfs_inode *nfsi;
473 struct address_space *mapping = folio->mapping;
474
475 /*
476 * Check if an unstable folio is currently being committed and
477 * if so, have the VM treat it as if the folio is under writeback
478 * so it will not block due to folios that will shortly be freeable.
479 */
480 nfsi = NFS_I(mapping->host);
481 if (atomic_read(&nfsi->commit_info.rpcs_out)) {
482 *writeback = true;
483 return;
484 }
485
486 /*
487 * If the private flag is set, then the folio is not freeable
488 * and as the inode is not being committed, it's not going to
489 * be cleaned in the near future so treat it as dirty
490 */
491 if (folio_test_private(folio))
492 *dirty = true;
493}
494
495/*
496 * Attempt to clear the private state associated with a page when an error
497 * occurs that requires the cached contents of an inode to be written back or
498 * destroyed
499 * - Called if either PG_private or fscache is set on the page
500 * - Caller holds page lock
501 * - Return 0 if successful, -error otherwise
502 */
503static int nfs_launder_folio(struct folio *folio)
504{
505 struct inode *inode = folio->mapping->host;
506 int ret;
507
508 dfprintk(PAGECACHE, "NFS: launder_folio(%ld, %llu)\n",
509 inode->i_ino, folio_pos(folio));
510
511 folio_wait_private_2(folio); /* [DEPRECATED] */
512 ret = nfs_wb_folio(inode, folio);
513 trace_nfs_launder_folio_done(inode, folio_pos(folio),
514 folio_size(folio), ret);
515 return ret;
516}
517
518static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
519 sector_t *span)
520{
521 unsigned long blocks;
522 long long isize;
523 int ret;
524 struct inode *inode = file_inode(file);
525 struct rpc_clnt *clnt = NFS_CLIENT(inode);
526 struct nfs_client *cl = NFS_SERVER(inode)->nfs_client;
527
528 spin_lock(&inode->i_lock);
529 blocks = inode->i_blocks;
530 isize = inode->i_size;
531 spin_unlock(&inode->i_lock);
532 if (blocks*512 < isize) {
533 pr_warn("swap activate: swapfile has holes\n");
534 return -EINVAL;
535 }
536
537 ret = rpc_clnt_swap_activate(clnt);
538 if (ret)
539 return ret;
540 ret = add_swap_extent(sis, 0, sis->max, 0);
541 if (ret < 0) {
542 rpc_clnt_swap_deactivate(clnt);
543 return ret;
544 }
545
546 *span = sis->pages;
547
548 if (cl->rpc_ops->enable_swap)
549 cl->rpc_ops->enable_swap(inode);
550
551 sis->flags |= SWP_FS_OPS;
552 return ret;
553}
554
555static void nfs_swap_deactivate(struct file *file)
556{
557 struct inode *inode = file_inode(file);
558 struct rpc_clnt *clnt = NFS_CLIENT(inode);
559 struct nfs_client *cl = NFS_SERVER(inode)->nfs_client;
560
561 rpc_clnt_swap_deactivate(clnt);
562 if (cl->rpc_ops->disable_swap)
563 cl->rpc_ops->disable_swap(file_inode(file));
564}
565
566const struct address_space_operations nfs_file_aops = {
567 .read_folio = nfs_read_folio,
568 .readahead = nfs_readahead,
569 .dirty_folio = filemap_dirty_folio,
570 .writepages = nfs_writepages,
571 .write_begin = nfs_write_begin,
572 .write_end = nfs_write_end,
573 .invalidate_folio = nfs_invalidate_folio,
574 .release_folio = nfs_release_folio,
575 .migrate_folio = nfs_migrate_folio,
576 .launder_folio = nfs_launder_folio,
577 .is_dirty_writeback = nfs_check_dirty_writeback,
578 .error_remove_folio = generic_error_remove_folio,
579 .swap_activate = nfs_swap_activate,
580 .swap_deactivate = nfs_swap_deactivate,
581 .swap_rw = nfs_swap_rw,
582};
583
584/*
585 * Notification that a PTE pointing to an NFS page is about to be made
586 * writable, implying that someone is about to modify the page through a
587 * shared-writable mapping
588 */
589static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf)
590{
591 struct file *filp = vmf->vma->vm_file;
592 struct inode *inode = file_inode(filp);
593 unsigned pagelen;
594 vm_fault_t ret = VM_FAULT_NOPAGE;
595 struct address_space *mapping;
596 struct folio *folio = page_folio(vmf->page);
597
598 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
599 filp, filp->f_mapping->host->i_ino,
600 (long long)folio_pos(folio));
601
602 sb_start_pagefault(inode->i_sb);
603
604 /* make sure the cache has finished storing the page */
605 if (folio_test_private_2(folio) && /* [DEPRECATED] */
606 folio_wait_private_2_killable(folio) < 0) {
607 ret = VM_FAULT_RETRY;
608 goto out;
609 }
610
611 wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
612 nfs_wait_bit_killable,
613 TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
614
615 folio_lock(folio);
616 mapping = folio->mapping;
617 if (mapping != inode->i_mapping)
618 goto out_unlock;
619
620 folio_wait_writeback(folio);
621
622 pagelen = nfs_folio_length(folio);
623 if (pagelen == 0)
624 goto out_unlock;
625
626 ret = VM_FAULT_LOCKED;
627 if (nfs_flush_incompatible(filp, folio) == 0 &&
628 nfs_update_folio(filp, folio, 0, pagelen) == 0)
629 goto out;
630
631 ret = VM_FAULT_SIGBUS;
632out_unlock:
633 folio_unlock(folio);
634out:
635 sb_end_pagefault(inode->i_sb);
636 return ret;
637}
638
639static const struct vm_operations_struct nfs_file_vm_ops = {
640 .fault = filemap_fault,
641 .map_pages = filemap_map_pages,
642 .page_mkwrite = nfs_vm_page_mkwrite,
643};
644
645ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
646{
647 struct file *file = iocb->ki_filp;
648 struct inode *inode = file_inode(file);
649 unsigned int mntflags = NFS_SERVER(inode)->flags;
650 ssize_t result, written;
651 errseq_t since;
652 int error;
653
654 result = nfs_key_timeout_notify(file, inode);
655 if (result)
656 return result;
657
658 if (iocb->ki_flags & IOCB_DIRECT)
659 return nfs_file_direct_write(iocb, from, false);
660
661 dprintk("NFS: write(%pD2, %zu@%Ld)\n",
662 file, iov_iter_count(from), (long long) iocb->ki_pos);
663
664 if (IS_SWAPFILE(inode))
665 goto out_swapfile;
666 /*
667 * O_APPEND implies that we must revalidate the file length.
668 */
669 if (iocb->ki_flags & IOCB_APPEND || iocb->ki_pos > i_size_read(inode)) {
670 result = nfs_revalidate_file_size(inode, file);
671 if (result)
672 return result;
673 }
674
675 nfs_clear_invalid_mapping(file->f_mapping);
676
677 since = filemap_sample_wb_err(file->f_mapping);
678 error = nfs_start_io_write(inode);
679 if (error)
680 return error;
681 result = generic_write_checks(iocb, from);
682 if (result > 0)
683 result = generic_perform_write(iocb, from);
684 nfs_end_io_write(inode);
685 if (result <= 0)
686 goto out;
687
688 written = result;
689 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
690
691 if (mntflags & NFS_MOUNT_WRITE_EAGER) {
692 result = filemap_fdatawrite_range(file->f_mapping,
693 iocb->ki_pos - written,
694 iocb->ki_pos - 1);
695 if (result < 0)
696 goto out;
697 }
698 if (mntflags & NFS_MOUNT_WRITE_WAIT) {
699 filemap_fdatawait_range(file->f_mapping,
700 iocb->ki_pos - written,
701 iocb->ki_pos - 1);
702 }
703 result = generic_write_sync(iocb, written);
704 if (result < 0)
705 return result;
706
707out:
708 /* Return error values */
709 error = filemap_check_wb_err(file->f_mapping, since);
710 switch (error) {
711 default:
712 break;
713 case -EDQUOT:
714 case -EFBIG:
715 case -ENOSPC:
716 nfs_wb_all(inode);
717 error = file_check_and_advance_wb_err(file);
718 if (error < 0)
719 result = error;
720 }
721 return result;
722
723out_swapfile:
724 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
725 return -ETXTBSY;
726}
727EXPORT_SYMBOL_GPL(nfs_file_write);
728
729static int
730do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
731{
732 struct inode *inode = filp->f_mapping->host;
733 int status = 0;
734 unsigned int saved_type = fl->c.flc_type;
735
736 /* Try local locking first */
737 posix_test_lock(filp, fl);
738 if (fl->c.flc_type != F_UNLCK) {
739 /* found a conflict */
740 goto out;
741 }
742 fl->c.flc_type = saved_type;
743
744 if (nfs_have_read_or_write_delegation(inode))
745 goto out_noconflict;
746
747 if (is_local)
748 goto out_noconflict;
749
750 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
751out:
752 return status;
753out_noconflict:
754 fl->c.flc_type = F_UNLCK;
755 goto out;
756}
757
758static int
759do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
760{
761 struct inode *inode = filp->f_mapping->host;
762 struct nfs_lock_context *l_ctx;
763 int status;
764
765 /*
766 * Flush all pending writes before doing anything
767 * with locks..
768 */
769 nfs_wb_all(inode);
770
771 l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
772 if (!IS_ERR(l_ctx)) {
773 status = nfs_iocounter_wait(l_ctx);
774 nfs_put_lock_context(l_ctx);
775 /* NOTE: special case
776 * If we're signalled while cleaning up locks on process exit, we
777 * still need to complete the unlock.
778 */
779 if (status < 0 && !(fl->c.flc_flags & FL_CLOSE))
780 return status;
781 }
782
783 /*
784 * Use local locking if mounted with "-onolock" or with appropriate
785 * "-olocal_lock="
786 */
787 if (!is_local)
788 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
789 else
790 status = locks_lock_file_wait(filp, fl);
791 return status;
792}
793
794static int
795do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
796{
797 struct inode *inode = filp->f_mapping->host;
798 int status;
799
800 /*
801 * Flush all pending writes before doing anything
802 * with locks..
803 */
804 status = nfs_sync_mapping(filp->f_mapping);
805 if (status != 0)
806 goto out;
807
808 /*
809 * Use local locking if mounted with "-onolock" or with appropriate
810 * "-olocal_lock="
811 */
812 if (!is_local)
813 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
814 else
815 status = locks_lock_file_wait(filp, fl);
816 if (status < 0)
817 goto out;
818
819 /*
820 * Invalidate cache to prevent missing any changes. If
821 * the file is mapped, clear the page cache as well so
822 * those mappings will be loaded.
823 *
824 * This makes locking act as a cache coherency point.
825 */
826 nfs_sync_mapping(filp->f_mapping);
827 if (!nfs_have_read_or_write_delegation(inode)) {
828 nfs_zap_caches(inode);
829 if (mapping_mapped(filp->f_mapping))
830 nfs_revalidate_mapping(inode, filp->f_mapping);
831 }
832out:
833 return status;
834}
835
836/*
837 * Lock a (portion of) a file
838 */
839int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
840{
841 struct inode *inode = filp->f_mapping->host;
842 int ret = -ENOLCK;
843 int is_local = 0;
844
845 dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n",
846 filp, fl->c.flc_type, fl->c.flc_flags,
847 (long long)fl->fl_start, (long long)fl->fl_end);
848
849 nfs_inc_stats(inode, NFSIOS_VFSLOCK);
850
851 if (fl->c.flc_flags & FL_RECLAIM)
852 return -ENOGRACE;
853
854 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
855 is_local = 1;
856
857 if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
858 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
859 if (ret < 0)
860 goto out_err;
861 }
862
863 if (IS_GETLK(cmd))
864 ret = do_getlk(filp, cmd, fl, is_local);
865 else if (lock_is_unlock(fl))
866 ret = do_unlk(filp, cmd, fl, is_local);
867 else
868 ret = do_setlk(filp, cmd, fl, is_local);
869out_err:
870 return ret;
871}
872EXPORT_SYMBOL_GPL(nfs_lock);
873
874/*
875 * Lock a (portion of) a file
876 */
877int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
878{
879 struct inode *inode = filp->f_mapping->host;
880 int is_local = 0;
881
882 dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n",
883 filp, fl->c.flc_type, fl->c.flc_flags);
884
885 if (!(fl->c.flc_flags & FL_FLOCK))
886 return -ENOLCK;
887
888 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
889 is_local = 1;
890
891 /* We're simulating flock() locks using posix locks on the server */
892 if (lock_is_unlock(fl))
893 return do_unlk(filp, cmd, fl, is_local);
894 return do_setlk(filp, cmd, fl, is_local);
895}
896EXPORT_SYMBOL_GPL(nfs_flock);
897
898const struct file_operations nfs_file_operations = {
899 .llseek = nfs_file_llseek,
900 .read_iter = nfs_file_read,
901 .write_iter = nfs_file_write,
902 .mmap = nfs_file_mmap,
903 .open = nfs_file_open,
904 .flush = nfs_file_flush,
905 .release = nfs_file_release,
906 .fsync = nfs_file_fsync,
907 .lock = nfs_lock,
908 .flock = nfs_flock,
909 .splice_read = nfs_file_splice_read,
910 .splice_write = iter_file_splice_write,
911 .check_flags = nfs_check_flags,
912 .setlease = simple_nosetlease,
913};
914EXPORT_SYMBOL_GPL(nfs_file_operations);