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