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