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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/*
2 * linux/fs/nfs/file.c
3 *
4 * Copyright (C) 1992 Rick Sladkey
5 *
6 * Changes Copyright (C) 1994 by Florian La Roche
7 * - Do not copy data too often around in the kernel.
8 * - In nfs_file_read the return value of kmalloc wasn't checked.
9 * - Put in a better version of read look-ahead buffering. Original idea
10 * and implementation by Wai S Kok elekokws@ee.nus.sg.
11 *
12 * Expire cache on write to a file by Wai S Kok (Oct 1994).
13 *
14 * Total rewrite of read side for new NFS buffer cache.. Linus.
15 *
16 * nfs regular file handling functions
17 */
18
19#include <linux/module.h>
20#include <linux/time.h>
21#include <linux/kernel.h>
22#include <linux/errno.h>
23#include <linux/fcntl.h>
24#include <linux/stat.h>
25#include <linux/nfs_fs.h>
26#include <linux/nfs_mount.h>
27#include <linux/mm.h>
28#include <linux/pagemap.h>
29#include <linux/gfp.h>
30#include <linux/swap.h>
31
32#include <asm/uaccess.h>
33
34#include "delegation.h"
35#include "internal.h"
36#include "iostat.h"
37#include "fscache.h"
38#include "pnfs.h"
39
40#include "nfstrace.h"
41
42#define NFSDBG_FACILITY NFSDBG_FILE
43
44static const struct vm_operations_struct nfs_file_vm_ops;
45
46/* Hack for future NFS swap support */
47#ifndef IS_SWAPFILE
48# define IS_SWAPFILE(inode) (0)
49#endif
50
51int nfs_check_flags(int flags)
52{
53 if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
54 return -EINVAL;
55
56 return 0;
57}
58EXPORT_SYMBOL_GPL(nfs_check_flags);
59
60/*
61 * Open file
62 */
63static int
64nfs_file_open(struct inode *inode, struct file *filp)
65{
66 int res;
67
68 dprintk("NFS: open file(%pD2)\n", filp);
69
70 nfs_inc_stats(inode, NFSIOS_VFSOPEN);
71 res = nfs_check_flags(filp->f_flags);
72 if (res)
73 return res;
74
75 res = nfs_open(inode, filp);
76 return res;
77}
78
79int
80nfs_file_release(struct inode *inode, struct file *filp)
81{
82 dprintk("NFS: release(%pD2)\n", filp);
83
84 nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
85 nfs_file_clear_open_context(filp);
86 return 0;
87}
88EXPORT_SYMBOL_GPL(nfs_file_release);
89
90/**
91 * nfs_revalidate_size - Revalidate the file size
92 * @inode - pointer to inode struct
93 * @file - pointer to struct file
94 *
95 * Revalidates the file length. This is basically a wrapper around
96 * nfs_revalidate_inode() that takes into account the fact that we may
97 * have cached writes (in which case we don't care about the server's
98 * idea of what the file length is), or O_DIRECT (in which case we
99 * shouldn't trust the cache).
100 */
101static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
102{
103 struct nfs_server *server = NFS_SERVER(inode);
104 struct nfs_inode *nfsi = NFS_I(inode);
105
106 if (nfs_have_delegated_attributes(inode))
107 goto out_noreval;
108
109 if (filp->f_flags & O_DIRECT)
110 goto force_reval;
111 if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
112 goto force_reval;
113 if (nfs_attribute_timeout(inode))
114 goto force_reval;
115out_noreval:
116 return 0;
117force_reval:
118 return __nfs_revalidate_inode(server, inode);
119}
120
121loff_t nfs_file_llseek(struct file *filp, loff_t offset, int whence)
122{
123 dprintk("NFS: llseek file(%pD2, %lld, %d)\n",
124 filp, offset, whence);
125
126 /*
127 * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
128 * the cached file length
129 */
130 if (whence != SEEK_SET && whence != SEEK_CUR) {
131 struct inode *inode = filp->f_mapping->host;
132
133 int retval = nfs_revalidate_file_size(inode, filp);
134 if (retval < 0)
135 return (loff_t)retval;
136 }
137
138 return generic_file_llseek(filp, offset, whence);
139}
140EXPORT_SYMBOL_GPL(nfs_file_llseek);
141
142/*
143 * Flush all dirty pages, and check for write errors.
144 */
145static int
146nfs_file_flush(struct file *file, fl_owner_t id)
147{
148 struct inode *inode = file_inode(file);
149
150 dprintk("NFS: flush(%pD2)\n", file);
151
152 nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
153 if ((file->f_mode & FMODE_WRITE) == 0)
154 return 0;
155
156 /* Flush writes to the server and return any errors */
157 return vfs_fsync(file, 0);
158}
159
160ssize_t
161nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
162{
163 struct inode *inode = file_inode(iocb->ki_filp);
164 ssize_t result;
165
166 if (iocb->ki_flags & IOCB_DIRECT)
167 return nfs_file_direct_read(iocb, to, iocb->ki_pos);
168
169 dprintk("NFS: read(%pD2, %zu@%lu)\n",
170 iocb->ki_filp,
171 iov_iter_count(to), (unsigned long) iocb->ki_pos);
172
173 result = nfs_revalidate_mapping_protected(inode, iocb->ki_filp->f_mapping);
174 if (!result) {
175 result = generic_file_read_iter(iocb, to);
176 if (result > 0)
177 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
178 }
179 return result;
180}
181EXPORT_SYMBOL_GPL(nfs_file_read);
182
183ssize_t
184nfs_file_splice_read(struct file *filp, loff_t *ppos,
185 struct pipe_inode_info *pipe, size_t count,
186 unsigned int flags)
187{
188 struct inode *inode = file_inode(filp);
189 ssize_t res;
190
191 dprintk("NFS: splice_read(%pD2, %lu@%Lu)\n",
192 filp, (unsigned long) count, (unsigned long long) *ppos);
193
194 res = nfs_revalidate_mapping_protected(inode, filp->f_mapping);
195 if (!res) {
196 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
197 if (res > 0)
198 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, res);
199 }
200 return res;
201}
202EXPORT_SYMBOL_GPL(nfs_file_splice_read);
203
204int
205nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
206{
207 struct inode *inode = file_inode(file);
208 int status;
209
210 dprintk("NFS: mmap(%pD2)\n", file);
211
212 /* Note: generic_file_mmap() returns ENOSYS on nommu systems
213 * so we call that before revalidating the mapping
214 */
215 status = generic_file_mmap(file, vma);
216 if (!status) {
217 vma->vm_ops = &nfs_file_vm_ops;
218 status = nfs_revalidate_mapping(inode, file->f_mapping);
219 }
220 return status;
221}
222EXPORT_SYMBOL_GPL(nfs_file_mmap);
223
224/*
225 * Flush any dirty pages for this process, and check for write errors.
226 * The return status from this call provides a reliable indication of
227 * whether any write errors occurred for this process.
228 *
229 * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
230 * disk, but it retrieves and clears ctx->error after synching, despite
231 * the two being set at the same time in nfs_context_set_write_error().
232 * This is because the former is used to notify the _next_ call to
233 * nfs_file_write() that a write error occurred, and hence cause it to
234 * fall back to doing a synchronous write.
235 */
236static int
237nfs_file_fsync_commit(struct file *file, loff_t start, loff_t end, int datasync)
238{
239 struct nfs_open_context *ctx = nfs_file_open_context(file);
240 struct inode *inode = file_inode(file);
241 int have_error, do_resend, status;
242 int ret = 0;
243
244 dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
245
246 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
247 do_resend = test_and_clear_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
248 have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
249 status = nfs_commit_inode(inode, FLUSH_SYNC);
250 have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
251 if (have_error) {
252 ret = xchg(&ctx->error, 0);
253 if (ret)
254 goto out;
255 }
256 if (status < 0) {
257 ret = status;
258 goto out;
259 }
260 do_resend |= test_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
261 if (do_resend)
262 ret = -EAGAIN;
263out:
264 return ret;
265}
266
267int
268nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
269{
270 int ret;
271 struct inode *inode = file_inode(file);
272
273 trace_nfs_fsync_enter(inode);
274
275 inode_dio_wait(inode);
276 do {
277 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
278 if (ret != 0)
279 break;
280 inode_lock(inode);
281 ret = nfs_file_fsync_commit(file, start, end, datasync);
282 if (!ret)
283 ret = pnfs_sync_inode(inode, !!datasync);
284 inode_unlock(inode);
285 /*
286 * If nfs_file_fsync_commit detected a server reboot, then
287 * resend all dirty pages that might have been covered by
288 * the NFS_CONTEXT_RESEND_WRITES flag
289 */
290 start = 0;
291 end = LLONG_MAX;
292 } while (ret == -EAGAIN);
293
294 trace_nfs_fsync_exit(inode, ret);
295 return ret;
296}
297EXPORT_SYMBOL_GPL(nfs_file_fsync);
298
299/*
300 * Decide whether a read/modify/write cycle may be more efficient
301 * then a modify/write/read cycle when writing to a page in the
302 * page cache.
303 *
304 * The modify/write/read cycle may occur if a page is read before
305 * being completely filled by the writer. In this situation, the
306 * page must be completely written to stable storage on the server
307 * before it can be refilled by reading in the page from the server.
308 * This can lead to expensive, small, FILE_SYNC mode writes being
309 * done.
310 *
311 * It may be more efficient to read the page first if the file is
312 * open for reading in addition to writing, the page is not marked
313 * as Uptodate, it is not dirty or waiting to be committed,
314 * indicating that it was previously allocated and then modified,
315 * that there were valid bytes of data in that range of the file,
316 * and that the new data won't completely replace the old data in
317 * that range of the file.
318 */
319static int nfs_want_read_modify_write(struct file *file, struct page *page,
320 loff_t pos, unsigned len)
321{
322 unsigned int pglen = nfs_page_length(page);
323 unsigned int offset = pos & (PAGE_SIZE - 1);
324 unsigned int end = offset + len;
325
326 if (pnfs_ld_read_whole_page(file->f_mapping->host)) {
327 if (!PageUptodate(page))
328 return 1;
329 return 0;
330 }
331
332 if ((file->f_mode & FMODE_READ) && /* open for read? */
333 !PageUptodate(page) && /* Uptodate? */
334 !PagePrivate(page) && /* i/o request already? */
335 pglen && /* valid bytes of file? */
336 (end < pglen || offset)) /* replace all valid bytes? */
337 return 1;
338 return 0;
339}
340
341/*
342 * This does the "real" work of the write. We must allocate and lock the
343 * page to be sent back to the generic routine, which then copies the
344 * data from user space.
345 *
346 * If the writer ends up delaying the write, the writer needs to
347 * increment the page use counts until he is done with the page.
348 */
349static int nfs_write_begin(struct file *file, struct address_space *mapping,
350 loff_t pos, unsigned len, unsigned flags,
351 struct page **pagep, void **fsdata)
352{
353 int ret;
354 pgoff_t index = pos >> PAGE_SHIFT;
355 struct page *page;
356 int once_thru = 0;
357
358 dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
359 file, mapping->host->i_ino, len, (long long) pos);
360
361start:
362 /*
363 * Prevent starvation issues if someone is doing a consistency
364 * sync-to-disk
365 */
366 ret = wait_on_bit_action(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
367 nfs_wait_bit_killable, TASK_KILLABLE);
368 if (ret)
369 return ret;
370 /*
371 * Wait for O_DIRECT to complete
372 */
373 inode_dio_wait(mapping->host);
374
375 page = grab_cache_page_write_begin(mapping, index, flags);
376 if (!page)
377 return -ENOMEM;
378 *pagep = page;
379
380 ret = nfs_flush_incompatible(file, page);
381 if (ret) {
382 unlock_page(page);
383 put_page(page);
384 } else if (!once_thru &&
385 nfs_want_read_modify_write(file, page, pos, len)) {
386 once_thru = 1;
387 ret = nfs_readpage(file, page);
388 put_page(page);
389 if (!ret)
390 goto start;
391 }
392 return ret;
393}
394
395static int nfs_write_end(struct file *file, struct address_space *mapping,
396 loff_t pos, unsigned len, unsigned copied,
397 struct page *page, void *fsdata)
398{
399 unsigned offset = pos & (PAGE_SIZE - 1);
400 struct nfs_open_context *ctx = nfs_file_open_context(file);
401 int status;
402
403 dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
404 file, mapping->host->i_ino, len, (long long) pos);
405
406 /*
407 * Zero any uninitialised parts of the page, and then mark the page
408 * as up to date if it turns out that we're extending the file.
409 */
410 if (!PageUptodate(page)) {
411 unsigned pglen = nfs_page_length(page);
412 unsigned end = offset + len;
413
414 if (pglen == 0) {
415 zero_user_segments(page, 0, offset,
416 end, PAGE_SIZE);
417 SetPageUptodate(page);
418 } else if (end >= pglen) {
419 zero_user_segment(page, end, PAGE_SIZE);
420 if (offset == 0)
421 SetPageUptodate(page);
422 } else
423 zero_user_segment(page, pglen, PAGE_SIZE);
424 }
425
426 status = nfs_updatepage(file, page, offset, copied);
427
428 unlock_page(page);
429 put_page(page);
430
431 if (status < 0)
432 return status;
433 NFS_I(mapping->host)->write_io += copied;
434
435 if (nfs_ctx_key_to_expire(ctx)) {
436 status = nfs_wb_all(mapping->host);
437 if (status < 0)
438 return status;
439 }
440
441 return copied;
442}
443
444/*
445 * Partially or wholly invalidate a page
446 * - Release the private state associated with a page if undergoing complete
447 * page invalidation
448 * - Called if either PG_private or PG_fscache is set on the page
449 * - Caller holds page lock
450 */
451static void nfs_invalidate_page(struct page *page, unsigned int offset,
452 unsigned int length)
453{
454 dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %u, %u)\n",
455 page, offset, length);
456
457 if (offset != 0 || length < PAGE_SIZE)
458 return;
459 /* Cancel any unstarted writes on this page */
460 nfs_wb_page_cancel(page_file_mapping(page)->host, page);
461
462 nfs_fscache_invalidate_page(page, page->mapping->host);
463}
464
465/*
466 * Attempt to release the private state associated with a page
467 * - Called if either PG_private or PG_fscache is set on the page
468 * - Caller holds page lock
469 * - Return true (may release page) or false (may not)
470 */
471static int nfs_release_page(struct page *page, gfp_t gfp)
472{
473 struct address_space *mapping = page->mapping;
474
475 dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
476
477 /* Always try to initiate a 'commit' if relevant, but only
478 * wait for it if the caller allows blocking. Even then,
479 * only wait 1 second and only if the 'bdi' is not congested.
480 * Waiting indefinitely can cause deadlocks when the NFS
481 * server is on this machine, when a new TCP connection is
482 * needed and in other rare cases. There is no particular
483 * need to wait extensively here. A short wait has the
484 * benefit that someone else can worry about the freezer.
485 */
486 if (mapping) {
487 struct nfs_server *nfss = NFS_SERVER(mapping->host);
488 nfs_commit_inode(mapping->host, 0);
489 if (gfpflags_allow_blocking(gfp) &&
490 !bdi_write_congested(&nfss->backing_dev_info)) {
491 wait_on_page_bit_killable_timeout(page, PG_private,
492 HZ);
493 if (PagePrivate(page))
494 set_bdi_congested(&nfss->backing_dev_info,
495 BLK_RW_ASYNC);
496 }
497 }
498 /* If PagePrivate() is set, then the page is not freeable */
499 if (PagePrivate(page))
500 return 0;
501 return nfs_fscache_release_page(page, gfp);
502}
503
504static void nfs_check_dirty_writeback(struct page *page,
505 bool *dirty, bool *writeback)
506{
507 struct nfs_inode *nfsi;
508 struct address_space *mapping = page_file_mapping(page);
509
510 if (!mapping || PageSwapCache(page))
511 return;
512
513 /*
514 * Check if an unstable page is currently being committed and
515 * if so, have the VM treat it as if the page is under writeback
516 * so it will not block due to pages that will shortly be freeable.
517 */
518 nfsi = NFS_I(mapping->host);
519 if (atomic_read(&nfsi->commit_info.rpcs_out)) {
520 *writeback = true;
521 return;
522 }
523
524 /*
525 * If PagePrivate() is set, then the page is not freeable and as the
526 * inode is not being committed, it's not going to be cleaned in the
527 * near future so treat it as dirty
528 */
529 if (PagePrivate(page))
530 *dirty = true;
531}
532
533/*
534 * Attempt to clear the private state associated with a page when an error
535 * occurs that requires the cached contents of an inode to be written back or
536 * destroyed
537 * - Called if either PG_private or fscache is set on the page
538 * - Caller holds page lock
539 * - Return 0 if successful, -error otherwise
540 */
541static int nfs_launder_page(struct page *page)
542{
543 struct inode *inode = page_file_mapping(page)->host;
544 struct nfs_inode *nfsi = NFS_I(inode);
545
546 dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
547 inode->i_ino, (long long)page_offset(page));
548
549 nfs_fscache_wait_on_page_write(nfsi, page);
550 return nfs_wb_launder_page(inode, page);
551}
552
553static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
554 sector_t *span)
555{
556 struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
557
558 *span = sis->pages;
559
560 return rpc_clnt_swap_activate(clnt);
561}
562
563static void nfs_swap_deactivate(struct file *file)
564{
565 struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
566
567 rpc_clnt_swap_deactivate(clnt);
568}
569
570const struct address_space_operations nfs_file_aops = {
571 .readpage = nfs_readpage,
572 .readpages = nfs_readpages,
573 .set_page_dirty = __set_page_dirty_nobuffers,
574 .writepage = nfs_writepage,
575 .writepages = nfs_writepages,
576 .write_begin = nfs_write_begin,
577 .write_end = nfs_write_end,
578 .invalidatepage = nfs_invalidate_page,
579 .releasepage = nfs_release_page,
580 .direct_IO = nfs_direct_IO,
581 .migratepage = nfs_migrate_page,
582 .launder_page = nfs_launder_page,
583 .is_dirty_writeback = nfs_check_dirty_writeback,
584 .error_remove_page = generic_error_remove_page,
585 .swap_activate = nfs_swap_activate,
586 .swap_deactivate = nfs_swap_deactivate,
587};
588
589/*
590 * Notification that a PTE pointing to an NFS page is about to be made
591 * writable, implying that someone is about to modify the page through a
592 * shared-writable mapping
593 */
594static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
595{
596 struct page *page = vmf->page;
597 struct file *filp = vma->vm_file;
598 struct inode *inode = file_inode(filp);
599 unsigned pagelen;
600 int ret = VM_FAULT_NOPAGE;
601 struct address_space *mapping;
602
603 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
604 filp, filp->f_mapping->host->i_ino,
605 (long long)page_offset(page));
606
607 /* make sure the cache has finished storing the page */
608 nfs_fscache_wait_on_page_write(NFS_I(inode), page);
609
610 wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
611 nfs_wait_bit_killable, TASK_KILLABLE);
612
613 lock_page(page);
614 mapping = page_file_mapping(page);
615 if (mapping != inode->i_mapping)
616 goto out_unlock;
617
618 wait_on_page_writeback(page);
619
620 pagelen = nfs_page_length(page);
621 if (pagelen == 0)
622 goto out_unlock;
623
624 ret = VM_FAULT_LOCKED;
625 if (nfs_flush_incompatible(filp, page) == 0 &&
626 nfs_updatepage(filp, page, 0, pagelen) == 0)
627 goto out;
628
629 ret = VM_FAULT_SIGBUS;
630out_unlock:
631 unlock_page(page);
632out:
633 return ret;
634}
635
636static const struct vm_operations_struct nfs_file_vm_ops = {
637 .fault = filemap_fault,
638 .map_pages = filemap_map_pages,
639 .page_mkwrite = nfs_vm_page_mkwrite,
640};
641
642static int nfs_need_check_write(struct file *filp, struct inode *inode)
643{
644 struct nfs_open_context *ctx;
645
646 ctx = nfs_file_open_context(filp);
647 if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags) ||
648 nfs_ctx_key_to_expire(ctx))
649 return 1;
650 return 0;
651}
652
653ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
654{
655 struct file *file = iocb->ki_filp;
656 struct inode *inode = file_inode(file);
657 unsigned long written = 0;
658 ssize_t result;
659 size_t count = iov_iter_count(from);
660
661 result = nfs_key_timeout_notify(file, inode);
662 if (result)
663 return result;
664
665 if (iocb->ki_flags & IOCB_DIRECT) {
666 result = generic_write_checks(iocb, from);
667 if (result <= 0)
668 return result;
669 return nfs_file_direct_write(iocb, from);
670 }
671
672 dprintk("NFS: write(%pD2, %zu@%Ld)\n",
673 file, count, (long long) iocb->ki_pos);
674
675 result = -EBUSY;
676 if (IS_SWAPFILE(inode))
677 goto out_swapfile;
678 /*
679 * O_APPEND implies that we must revalidate the file length.
680 */
681 if (iocb->ki_flags & IOCB_APPEND) {
682 result = nfs_revalidate_file_size(inode, file);
683 if (result)
684 goto out;
685 }
686
687 result = count;
688 if (!count)
689 goto out;
690
691 result = generic_file_write_iter(iocb, from);
692 if (result > 0)
693 written = result;
694
695 /* Return error values */
696 if (result >= 0 && nfs_need_check_write(file, inode)) {
697 int err = vfs_fsync(file, 0);
698 if (err < 0)
699 result = err;
700 }
701 if (result > 0)
702 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
703out:
704 return result;
705
706out_swapfile:
707 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
708 goto out;
709}
710EXPORT_SYMBOL_GPL(nfs_file_write);
711
712static int
713do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
714{
715 struct inode *inode = filp->f_mapping->host;
716 int status = 0;
717 unsigned int saved_type = fl->fl_type;
718
719 /* Try local locking first */
720 posix_test_lock(filp, fl);
721 if (fl->fl_type != F_UNLCK) {
722 /* found a conflict */
723 goto out;
724 }
725 fl->fl_type = saved_type;
726
727 if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
728 goto out_noconflict;
729
730 if (is_local)
731 goto out_noconflict;
732
733 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
734out:
735 return status;
736out_noconflict:
737 fl->fl_type = F_UNLCK;
738 goto out;
739}
740
741static int do_vfs_lock(struct file *file, struct file_lock *fl)
742{
743 return locks_lock_file_wait(file, fl);
744}
745
746static int
747do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
748{
749 struct inode *inode = filp->f_mapping->host;
750 struct nfs_lock_context *l_ctx;
751 int status;
752
753 /*
754 * Flush all pending writes before doing anything
755 * with locks..
756 */
757 vfs_fsync(filp, 0);
758
759 l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
760 if (!IS_ERR(l_ctx)) {
761 status = nfs_iocounter_wait(l_ctx);
762 nfs_put_lock_context(l_ctx);
763 if (status < 0)
764 return status;
765 }
766
767 /* NOTE: special case
768 * If we're signalled while cleaning up locks on process exit, we
769 * still need to complete the unlock.
770 */
771 /*
772 * Use local locking if mounted with "-onolock" or with appropriate
773 * "-olocal_lock="
774 */
775 if (!is_local)
776 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
777 else
778 status = do_vfs_lock(filp, fl);
779 return status;
780}
781
782static int
783is_time_granular(struct timespec *ts) {
784 return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000));
785}
786
787static int
788do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
789{
790 struct inode *inode = filp->f_mapping->host;
791 int status;
792
793 /*
794 * Flush all pending writes before doing anything
795 * with locks..
796 */
797 status = nfs_sync_mapping(filp->f_mapping);
798 if (status != 0)
799 goto out;
800
801 /*
802 * Use local locking if mounted with "-onolock" or with appropriate
803 * "-olocal_lock="
804 */
805 if (!is_local)
806 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
807 else
808 status = do_vfs_lock(filp, fl);
809 if (status < 0)
810 goto out;
811
812 /*
813 * Revalidate the cache if the server has time stamps granular
814 * enough to detect subsecond changes. Otherwise, clear the
815 * cache to prevent missing any changes.
816 *
817 * This makes locking act as a cache coherency point.
818 */
819 nfs_sync_mapping(filp->f_mapping);
820 if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) {
821 if (is_time_granular(&NFS_SERVER(inode)->time_delta))
822 __nfs_revalidate_inode(NFS_SERVER(inode), inode);
823 else
824 nfs_zap_caches(inode);
825 }
826out:
827 return status;
828}
829
830/*
831 * Lock a (portion of) a file
832 */
833int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
834{
835 struct inode *inode = filp->f_mapping->host;
836 int ret = -ENOLCK;
837 int is_local = 0;
838
839 dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n",
840 filp, fl->fl_type, fl->fl_flags,
841 (long long)fl->fl_start, (long long)fl->fl_end);
842
843 nfs_inc_stats(inode, NFSIOS_VFSLOCK);
844
845 /* No mandatory locks over NFS */
846 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
847 goto out_err;
848
849 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
850 is_local = 1;
851
852 if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
853 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
854 if (ret < 0)
855 goto out_err;
856 }
857
858 if (IS_GETLK(cmd))
859 ret = do_getlk(filp, cmd, fl, is_local);
860 else if (fl->fl_type == F_UNLCK)
861 ret = do_unlk(filp, cmd, fl, is_local);
862 else
863 ret = do_setlk(filp, cmd, fl, is_local);
864out_err:
865 return ret;
866}
867EXPORT_SYMBOL_GPL(nfs_lock);
868
869/*
870 * Lock a (portion of) a file
871 */
872int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
873{
874 struct inode *inode = filp->f_mapping->host;
875 int is_local = 0;
876
877 dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n",
878 filp, fl->fl_type, fl->fl_flags);
879
880 if (!(fl->fl_flags & FL_FLOCK))
881 return -ENOLCK;
882
883 /*
884 * The NFSv4 protocol doesn't support LOCK_MAND, which is not part of
885 * any standard. In principle we might be able to support LOCK_MAND
886 * on NFSv2/3 since NLMv3/4 support DOS share modes, but for now the
887 * NFS code is not set up for it.
888 */
889 if (fl->fl_type & LOCK_MAND)
890 return -EINVAL;
891
892 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
893 is_local = 1;
894
895 /* We're simulating flock() locks using posix locks on the server */
896 if (fl->fl_type == F_UNLCK)
897 return do_unlk(filp, cmd, fl, is_local);
898 return do_setlk(filp, cmd, fl, is_local);
899}
900EXPORT_SYMBOL_GPL(nfs_flock);
901
902const struct file_operations nfs_file_operations = {
903 .llseek = nfs_file_llseek,
904 .read_iter = nfs_file_read,
905 .write_iter = nfs_file_write,
906 .mmap = nfs_file_mmap,
907 .open = nfs_file_open,
908 .flush = nfs_file_flush,
909 .release = nfs_file_release,
910 .fsync = nfs_file_fsync,
911 .lock = nfs_lock,
912 .flock = nfs_flock,
913 .splice_read = nfs_file_splice_read,
914 .splice_write = iter_file_splice_write,
915 .check_flags = nfs_check_flags,
916 .setlease = simple_nosetlease,
917};
918EXPORT_SYMBOL_GPL(nfs_file_operations);