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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/time.h>
20#include <linux/kernel.h>
21#include <linux/errno.h>
22#include <linux/fcntl.h>
23#include <linux/stat.h>
24#include <linux/nfs_fs.h>
25#include <linux/nfs_mount.h>
26#include <linux/mm.h>
27#include <linux/pagemap.h>
28#include <linux/aio.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#define NFSDBG_FACILITY NFSDBG_FILE
41
42static const struct vm_operations_struct nfs_file_vm_ops;
43
44const struct inode_operations nfs_file_inode_operations = {
45 .permission = nfs_permission,
46 .getattr = nfs_getattr,
47 .setattr = nfs_setattr,
48};
49
50#ifdef CONFIG_NFS_V3
51const struct inode_operations nfs3_file_inode_operations = {
52 .permission = nfs_permission,
53 .getattr = nfs_getattr,
54 .setattr = nfs_setattr,
55 .listxattr = nfs3_listxattr,
56 .getxattr = nfs3_getxattr,
57 .setxattr = nfs3_setxattr,
58 .removexattr = nfs3_removexattr,
59};
60#endif /* CONFIG_NFS_v3 */
61
62/* Hack for future NFS swap support */
63#ifndef IS_SWAPFILE
64# define IS_SWAPFILE(inode) (0)
65#endif
66
67static int nfs_check_flags(int flags)
68{
69 if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
70 return -EINVAL;
71
72 return 0;
73}
74
75/*
76 * Open file
77 */
78static int
79nfs_file_open(struct inode *inode, struct file *filp)
80{
81 int res;
82
83 dprintk("NFS: open file(%s/%s)\n",
84 filp->f_path.dentry->d_parent->d_name.name,
85 filp->f_path.dentry->d_name.name);
86
87 nfs_inc_stats(inode, NFSIOS_VFSOPEN);
88 res = nfs_check_flags(filp->f_flags);
89 if (res)
90 return res;
91
92 res = nfs_open(inode, filp);
93 return res;
94}
95
96static int
97nfs_file_release(struct inode *inode, struct file *filp)
98{
99 dprintk("NFS: release(%s/%s)\n",
100 filp->f_path.dentry->d_parent->d_name.name,
101 filp->f_path.dentry->d_name.name);
102
103 nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
104 return nfs_release(inode, filp);
105}
106
107/**
108 * nfs_revalidate_size - Revalidate the file size
109 * @inode - pointer to inode struct
110 * @file - pointer to struct file
111 *
112 * Revalidates the file length. This is basically a wrapper around
113 * nfs_revalidate_inode() that takes into account the fact that we may
114 * have cached writes (in which case we don't care about the server's
115 * idea of what the file length is), or O_DIRECT (in which case we
116 * shouldn't trust the cache).
117 */
118static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
119{
120 struct nfs_server *server = NFS_SERVER(inode);
121 struct nfs_inode *nfsi = NFS_I(inode);
122
123 if (nfs_have_delegated_attributes(inode))
124 goto out_noreval;
125
126 if (filp->f_flags & O_DIRECT)
127 goto force_reval;
128 if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
129 goto force_reval;
130 if (nfs_attribute_timeout(inode))
131 goto force_reval;
132out_noreval:
133 return 0;
134force_reval:
135 return __nfs_revalidate_inode(server, inode);
136}
137
138static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
139{
140 dprintk("NFS: llseek file(%s/%s, %lld, %d)\n",
141 filp->f_path.dentry->d_parent->d_name.name,
142 filp->f_path.dentry->d_name.name,
143 offset, origin);
144
145 /*
146 * origin == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
147 * the cached file length
148 */
149 if (origin != SEEK_SET && origin != SEEK_CUR) {
150 struct inode *inode = filp->f_mapping->host;
151
152 int retval = nfs_revalidate_file_size(inode, filp);
153 if (retval < 0)
154 return (loff_t)retval;
155 }
156
157 return generic_file_llseek(filp, offset, origin);
158}
159
160/*
161 * Flush all dirty pages, and check for write errors.
162 */
163static int
164nfs_file_flush(struct file *file, fl_owner_t id)
165{
166 struct dentry *dentry = file->f_path.dentry;
167 struct inode *inode = dentry->d_inode;
168
169 dprintk("NFS: flush(%s/%s)\n",
170 dentry->d_parent->d_name.name,
171 dentry->d_name.name);
172
173 nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
174 if ((file->f_mode & FMODE_WRITE) == 0)
175 return 0;
176
177 /*
178 * If we're holding a write delegation, then just start the i/o
179 * but don't wait for completion (or send a commit).
180 */
181 if (nfs_have_delegation(inode, FMODE_WRITE))
182 return filemap_fdatawrite(file->f_mapping);
183
184 /* Flush writes to the server and return any errors */
185 return vfs_fsync(file, 0);
186}
187
188static ssize_t
189nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
190 unsigned long nr_segs, loff_t pos)
191{
192 struct dentry * dentry = iocb->ki_filp->f_path.dentry;
193 struct inode * inode = dentry->d_inode;
194 ssize_t result;
195
196 if (iocb->ki_filp->f_flags & O_DIRECT)
197 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
198
199 dprintk("NFS: read(%s/%s, %lu@%lu)\n",
200 dentry->d_parent->d_name.name, dentry->d_name.name,
201 (unsigned long) iov_length(iov, nr_segs), (unsigned long) pos);
202
203 result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
204 if (!result) {
205 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
206 if (result > 0)
207 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
208 }
209 return result;
210}
211
212static ssize_t
213nfs_file_splice_read(struct file *filp, loff_t *ppos,
214 struct pipe_inode_info *pipe, size_t count,
215 unsigned int flags)
216{
217 struct dentry *dentry = filp->f_path.dentry;
218 struct inode *inode = dentry->d_inode;
219 ssize_t res;
220
221 dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n",
222 dentry->d_parent->d_name.name, dentry->d_name.name,
223 (unsigned long) count, (unsigned long long) *ppos);
224
225 res = nfs_revalidate_mapping(inode, filp->f_mapping);
226 if (!res) {
227 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
228 if (res > 0)
229 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, res);
230 }
231 return res;
232}
233
234static int
235nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
236{
237 struct dentry *dentry = file->f_path.dentry;
238 struct inode *inode = dentry->d_inode;
239 int status;
240
241 dprintk("NFS: mmap(%s/%s)\n",
242 dentry->d_parent->d_name.name, dentry->d_name.name);
243
244 /* Note: generic_file_mmap() returns ENOSYS on nommu systems
245 * so we call that before revalidating the mapping
246 */
247 status = generic_file_mmap(file, vma);
248 if (!status) {
249 vma->vm_ops = &nfs_file_vm_ops;
250 status = nfs_revalidate_mapping(inode, file->f_mapping);
251 }
252 return status;
253}
254
255/*
256 * Flush any dirty pages for this process, and check for write errors.
257 * The return status from this call provides a reliable indication of
258 * whether any write errors occurred for this process.
259 *
260 * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
261 * disk, but it retrieves and clears ctx->error after synching, despite
262 * the two being set at the same time in nfs_context_set_write_error().
263 * This is because the former is used to notify the _next_ call to
264 * nfs_file_write() that a write error occurred, and hence cause it to
265 * fall back to doing a synchronous write.
266 */
267static int
268nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
269{
270 struct dentry *dentry = file->f_path.dentry;
271 struct nfs_open_context *ctx = nfs_file_open_context(file);
272 struct inode *inode = dentry->d_inode;
273 int have_error, status;
274 int ret = 0;
275
276 dprintk("NFS: fsync file(%s/%s) datasync %d\n",
277 dentry->d_parent->d_name.name, dentry->d_name.name,
278 datasync);
279
280 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
281 mutex_lock(&inode->i_mutex);
282
283 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
284 have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
285 status = nfs_commit_inode(inode, FLUSH_SYNC);
286 if (status >= 0 && ret < 0)
287 status = ret;
288 have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
289 if (have_error)
290 ret = xchg(&ctx->error, 0);
291 if (!ret && status < 0)
292 ret = status;
293 if (!ret && !datasync)
294 /* application has asked for meta-data sync */
295 ret = pnfs_layoutcommit_inode(inode, true);
296 mutex_unlock(&inode->i_mutex);
297 return ret;
298}
299
300/*
301 * Decide whether a read/modify/write cycle may be more efficient
302 * then a modify/write/read cycle when writing to a page in the
303 * page cache.
304 *
305 * The modify/write/read cycle may occur if a page is read before
306 * being completely filled by the writer. In this situation, the
307 * page must be completely written to stable storage on the server
308 * before it can be refilled by reading in the page from the server.
309 * This can lead to expensive, small, FILE_SYNC mode writes being
310 * done.
311 *
312 * It may be more efficient to read the page first if the file is
313 * open for reading in addition to writing, the page is not marked
314 * as Uptodate, it is not dirty or waiting to be committed,
315 * indicating that it was previously allocated and then modified,
316 * that there were valid bytes of data in that range of the file,
317 * and that the new data won't completely replace the old data in
318 * that range of the file.
319 */
320static int nfs_want_read_modify_write(struct file *file, struct page *page,
321 loff_t pos, unsigned len)
322{
323 unsigned int pglen = nfs_page_length(page);
324 unsigned int offset = pos & (PAGE_CACHE_SIZE - 1);
325 unsigned int end = offset + len;
326
327 if ((file->f_mode & FMODE_READ) && /* open for read? */
328 !PageUptodate(page) && /* Uptodate? */
329 !PagePrivate(page) && /* i/o request already? */
330 pglen && /* valid bytes of file? */
331 (end < pglen || offset)) /* replace all valid bytes? */
332 return 1;
333 return 0;
334}
335
336/*
337 * This does the "real" work of the write. We must allocate and lock the
338 * page to be sent back to the generic routine, which then copies the
339 * data from user space.
340 *
341 * If the writer ends up delaying the write, the writer needs to
342 * increment the page use counts until he is done with the page.
343 */
344static int nfs_write_begin(struct file *file, struct address_space *mapping,
345 loff_t pos, unsigned len, unsigned flags,
346 struct page **pagep, void **fsdata)
347{
348 int ret;
349 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
350 struct page *page;
351 int once_thru = 0;
352
353 dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n",
354 file->f_path.dentry->d_parent->d_name.name,
355 file->f_path.dentry->d_name.name,
356 mapping->host->i_ino, len, (long long) pos);
357
358start:
359 /*
360 * Prevent starvation issues if someone is doing a consistency
361 * sync-to-disk
362 */
363 ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
364 nfs_wait_bit_killable, TASK_KILLABLE);
365 if (ret)
366 return ret;
367
368 page = grab_cache_page_write_begin(mapping, index, flags);
369 if (!page)
370 return -ENOMEM;
371 *pagep = page;
372
373 ret = nfs_flush_incompatible(file, page);
374 if (ret) {
375 unlock_page(page);
376 page_cache_release(page);
377 } else if (!once_thru &&
378 nfs_want_read_modify_write(file, page, pos, len)) {
379 once_thru = 1;
380 ret = nfs_readpage(file, page);
381 page_cache_release(page);
382 if (!ret)
383 goto start;
384 }
385 return ret;
386}
387
388static int nfs_write_end(struct file *file, struct address_space *mapping,
389 loff_t pos, unsigned len, unsigned copied,
390 struct page *page, void *fsdata)
391{
392 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
393 int status;
394
395 dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n",
396 file->f_path.dentry->d_parent->d_name.name,
397 file->f_path.dentry->d_name.name,
398 mapping->host->i_ino, len, (long long) pos);
399
400 /*
401 * Zero any uninitialised parts of the page, and then mark the page
402 * as up to date if it turns out that we're extending the file.
403 */
404 if (!PageUptodate(page)) {
405 unsigned pglen = nfs_page_length(page);
406 unsigned end = offset + len;
407
408 if (pglen == 0) {
409 zero_user_segments(page, 0, offset,
410 end, PAGE_CACHE_SIZE);
411 SetPageUptodate(page);
412 } else if (end >= pglen) {
413 zero_user_segment(page, end, PAGE_CACHE_SIZE);
414 if (offset == 0)
415 SetPageUptodate(page);
416 } else
417 zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
418 }
419
420 status = nfs_updatepage(file, page, offset, copied);
421
422 unlock_page(page);
423 page_cache_release(page);
424
425 if (status < 0)
426 return status;
427 NFS_I(mapping->host)->write_io += copied;
428 return copied;
429}
430
431/*
432 * Partially or wholly invalidate a page
433 * - Release the private state associated with a page if undergoing complete
434 * page invalidation
435 * - Called if either PG_private or PG_fscache is set on the page
436 * - Caller holds page lock
437 */
438static void nfs_invalidate_page(struct page *page, unsigned long offset)
439{
440 dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
441
442 if (offset != 0)
443 return;
444 /* Cancel any unstarted writes on this page */
445 nfs_wb_page_cancel(page->mapping->host, page);
446
447 nfs_fscache_invalidate_page(page, page->mapping->host);
448}
449
450/*
451 * Attempt to release the private state associated with a page
452 * - Called if either PG_private or PG_fscache is set on the page
453 * - Caller holds page lock
454 * - Return true (may release page) or false (may not)
455 */
456static int nfs_release_page(struct page *page, gfp_t gfp)
457{
458 struct address_space *mapping = page->mapping;
459
460 dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
461
462 /* Only do I/O if gfp is a superset of GFP_KERNEL, and we're not
463 * doing this memory reclaim for a fs-related allocation.
464 */
465 if (mapping && (gfp & GFP_KERNEL) == GFP_KERNEL &&
466 !(current->flags & PF_FSTRANS)) {
467 int how = FLUSH_SYNC;
468
469 /* Don't let kswapd deadlock waiting for OOM RPC calls */
470 if (current_is_kswapd())
471 how = 0;
472 nfs_commit_inode(mapping->host, how);
473 }
474 /* If PagePrivate() is set, then the page is not freeable */
475 if (PagePrivate(page))
476 return 0;
477 return nfs_fscache_release_page(page, gfp);
478}
479
480/*
481 * Attempt to clear the private state associated with a page when an error
482 * occurs that requires the cached contents of an inode to be written back or
483 * destroyed
484 * - Called if either PG_private or fscache is set on the page
485 * - Caller holds page lock
486 * - Return 0 if successful, -error otherwise
487 */
488static int nfs_launder_page(struct page *page)
489{
490 struct inode *inode = page->mapping->host;
491 struct nfs_inode *nfsi = NFS_I(inode);
492
493 dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
494 inode->i_ino, (long long)page_offset(page));
495
496 nfs_fscache_wait_on_page_write(nfsi, page);
497 return nfs_wb_page(inode, page);
498}
499
500const struct address_space_operations nfs_file_aops = {
501 .readpage = nfs_readpage,
502 .readpages = nfs_readpages,
503 .set_page_dirty = __set_page_dirty_nobuffers,
504 .writepage = nfs_writepage,
505 .writepages = nfs_writepages,
506 .write_begin = nfs_write_begin,
507 .write_end = nfs_write_end,
508 .invalidatepage = nfs_invalidate_page,
509 .releasepage = nfs_release_page,
510 .direct_IO = nfs_direct_IO,
511 .migratepage = nfs_migrate_page,
512 .launder_page = nfs_launder_page,
513 .error_remove_page = generic_error_remove_page,
514};
515
516/*
517 * Notification that a PTE pointing to an NFS page is about to be made
518 * writable, implying that someone is about to modify the page through a
519 * shared-writable mapping
520 */
521static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
522{
523 struct page *page = vmf->page;
524 struct file *filp = vma->vm_file;
525 struct dentry *dentry = filp->f_path.dentry;
526 unsigned pagelen;
527 int ret = VM_FAULT_NOPAGE;
528 struct address_space *mapping;
529
530 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
531 dentry->d_parent->d_name.name, dentry->d_name.name,
532 filp->f_mapping->host->i_ino,
533 (long long)page_offset(page));
534
535 /* make sure the cache has finished storing the page */
536 nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
537
538 lock_page(page);
539 mapping = page->mapping;
540 if (mapping != dentry->d_inode->i_mapping)
541 goto out_unlock;
542
543 wait_on_page_writeback(page);
544
545 pagelen = nfs_page_length(page);
546 if (pagelen == 0)
547 goto out_unlock;
548
549 ret = VM_FAULT_LOCKED;
550 if (nfs_flush_incompatible(filp, page) == 0 &&
551 nfs_updatepage(filp, page, 0, pagelen) == 0)
552 goto out;
553
554 ret = VM_FAULT_SIGBUS;
555out_unlock:
556 unlock_page(page);
557out:
558 return ret;
559}
560
561static const struct vm_operations_struct nfs_file_vm_ops = {
562 .fault = filemap_fault,
563 .page_mkwrite = nfs_vm_page_mkwrite,
564};
565
566static int nfs_need_sync_write(struct file *filp, struct inode *inode)
567{
568 struct nfs_open_context *ctx;
569
570 if (IS_SYNC(inode) || (filp->f_flags & O_DSYNC))
571 return 1;
572 ctx = nfs_file_open_context(filp);
573 if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
574 return 1;
575 return 0;
576}
577
578static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
579 unsigned long nr_segs, loff_t pos)
580{
581 struct dentry * dentry = iocb->ki_filp->f_path.dentry;
582 struct inode * inode = dentry->d_inode;
583 unsigned long written = 0;
584 ssize_t result;
585 size_t count = iov_length(iov, nr_segs);
586
587 if (iocb->ki_filp->f_flags & O_DIRECT)
588 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
589
590 dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
591 dentry->d_parent->d_name.name, dentry->d_name.name,
592 (unsigned long) count, (long long) pos);
593
594 result = -EBUSY;
595 if (IS_SWAPFILE(inode))
596 goto out_swapfile;
597 /*
598 * O_APPEND implies that we must revalidate the file length.
599 */
600 if (iocb->ki_filp->f_flags & O_APPEND) {
601 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
602 if (result)
603 goto out;
604 }
605
606 result = count;
607 if (!count)
608 goto out;
609
610 result = generic_file_aio_write(iocb, iov, nr_segs, pos);
611 if (result > 0)
612 written = result;
613
614 /* Return error values for O_DSYNC and IS_SYNC() */
615 if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
616 int err = vfs_fsync(iocb->ki_filp, 0);
617 if (err < 0)
618 result = err;
619 }
620 if (result > 0)
621 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
622out:
623 return result;
624
625out_swapfile:
626 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
627 goto out;
628}
629
630static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
631 struct file *filp, loff_t *ppos,
632 size_t count, unsigned int flags)
633{
634 struct dentry *dentry = filp->f_path.dentry;
635 struct inode *inode = dentry->d_inode;
636 unsigned long written = 0;
637 ssize_t ret;
638
639 dprintk("NFS splice_write(%s/%s, %lu@%llu)\n",
640 dentry->d_parent->d_name.name, dentry->d_name.name,
641 (unsigned long) count, (unsigned long long) *ppos);
642
643 /*
644 * The combination of splice and an O_APPEND destination is disallowed.
645 */
646
647 ret = generic_file_splice_write(pipe, filp, ppos, count, flags);
648 if (ret > 0)
649 written = ret;
650
651 if (ret >= 0 && nfs_need_sync_write(filp, inode)) {
652 int err = vfs_fsync(filp, 0);
653 if (err < 0)
654 ret = err;
655 }
656 if (ret > 0)
657 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
658 return ret;
659}
660
661static int
662do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
663{
664 struct inode *inode = filp->f_mapping->host;
665 int status = 0;
666 unsigned int saved_type = fl->fl_type;
667
668 /* Try local locking first */
669 posix_test_lock(filp, fl);
670 if (fl->fl_type != F_UNLCK) {
671 /* found a conflict */
672 goto out;
673 }
674 fl->fl_type = saved_type;
675
676 if (nfs_have_delegation(inode, FMODE_READ))
677 goto out_noconflict;
678
679 if (is_local)
680 goto out_noconflict;
681
682 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
683out:
684 return status;
685out_noconflict:
686 fl->fl_type = F_UNLCK;
687 goto out;
688}
689
690static int do_vfs_lock(struct file *file, struct file_lock *fl)
691{
692 int res = 0;
693 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
694 case FL_POSIX:
695 res = posix_lock_file_wait(file, fl);
696 break;
697 case FL_FLOCK:
698 res = flock_lock_file_wait(file, fl);
699 break;
700 default:
701 BUG();
702 }
703 return res;
704}
705
706static int
707do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
708{
709 struct inode *inode = filp->f_mapping->host;
710 int status;
711
712 /*
713 * Flush all pending writes before doing anything
714 * with locks..
715 */
716 nfs_sync_mapping(filp->f_mapping);
717
718 /* NOTE: special case
719 * If we're signalled while cleaning up locks on process exit, we
720 * still need to complete the unlock.
721 */
722 /*
723 * Use local locking if mounted with "-onolock" or with appropriate
724 * "-olocal_lock="
725 */
726 if (!is_local)
727 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
728 else
729 status = do_vfs_lock(filp, fl);
730 return status;
731}
732
733static int
734is_time_granular(struct timespec *ts) {
735 return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000));
736}
737
738static int
739do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
740{
741 struct inode *inode = filp->f_mapping->host;
742 int status;
743
744 /*
745 * Flush all pending writes before doing anything
746 * with locks..
747 */
748 status = nfs_sync_mapping(filp->f_mapping);
749 if (status != 0)
750 goto out;
751
752 /*
753 * Use local locking if mounted with "-onolock" or with appropriate
754 * "-olocal_lock="
755 */
756 if (!is_local)
757 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
758 else
759 status = do_vfs_lock(filp, fl);
760 if (status < 0)
761 goto out;
762
763 /*
764 * Revalidate the cache if the server has time stamps granular
765 * enough to detect subsecond changes. Otherwise, clear the
766 * cache to prevent missing any changes.
767 *
768 * This makes locking act as a cache coherency point.
769 */
770 nfs_sync_mapping(filp->f_mapping);
771 if (!nfs_have_delegation(inode, FMODE_READ)) {
772 if (is_time_granular(&NFS_SERVER(inode)->time_delta))
773 __nfs_revalidate_inode(NFS_SERVER(inode), inode);
774 else
775 nfs_zap_caches(inode);
776 }
777out:
778 return status;
779}
780
781/*
782 * Lock a (portion of) a file
783 */
784static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
785{
786 struct inode *inode = filp->f_mapping->host;
787 int ret = -ENOLCK;
788 int is_local = 0;
789
790 dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n",
791 filp->f_path.dentry->d_parent->d_name.name,
792 filp->f_path.dentry->d_name.name,
793 fl->fl_type, fl->fl_flags,
794 (long long)fl->fl_start, (long long)fl->fl_end);
795
796 nfs_inc_stats(inode, NFSIOS_VFSLOCK);
797
798 /* No mandatory locks over NFS */
799 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
800 goto out_err;
801
802 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
803 is_local = 1;
804
805 if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
806 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
807 if (ret < 0)
808 goto out_err;
809 }
810
811 if (IS_GETLK(cmd))
812 ret = do_getlk(filp, cmd, fl, is_local);
813 else if (fl->fl_type == F_UNLCK)
814 ret = do_unlk(filp, cmd, fl, is_local);
815 else
816 ret = do_setlk(filp, cmd, fl, is_local);
817out_err:
818 return ret;
819}
820
821/*
822 * Lock a (portion of) a file
823 */
824static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
825{
826 struct inode *inode = filp->f_mapping->host;
827 int is_local = 0;
828
829 dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n",
830 filp->f_path.dentry->d_parent->d_name.name,
831 filp->f_path.dentry->d_name.name,
832 fl->fl_type, fl->fl_flags);
833
834 if (!(fl->fl_flags & FL_FLOCK))
835 return -ENOLCK;
836
837 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
838 is_local = 1;
839
840 /* We're simulating flock() locks using posix locks on the server */
841 fl->fl_owner = (fl_owner_t)filp;
842 fl->fl_start = 0;
843 fl->fl_end = OFFSET_MAX;
844
845 if (fl->fl_type == F_UNLCK)
846 return do_unlk(filp, cmd, fl, is_local);
847 return do_setlk(filp, cmd, fl, is_local);
848}
849
850/*
851 * There is no protocol support for leases, so we have no way to implement
852 * them correctly in the face of opens by other clients.
853 */
854static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
855{
856 dprintk("NFS: setlease(%s/%s, arg=%ld)\n",
857 file->f_path.dentry->d_parent->d_name.name,
858 file->f_path.dentry->d_name.name, arg);
859 return -EINVAL;
860}
861
862const struct file_operations nfs_file_operations = {
863 .llseek = nfs_file_llseek,
864 .read = do_sync_read,
865 .write = do_sync_write,
866 .aio_read = nfs_file_read,
867 .aio_write = nfs_file_write,
868 .mmap = nfs_file_mmap,
869 .open = nfs_file_open,
870 .flush = nfs_file_flush,
871 .release = nfs_file_release,
872 .fsync = nfs_file_fsync,
873 .lock = nfs_lock,
874 .flock = nfs_flock,
875 .splice_read = nfs_file_splice_read,
876 .splice_write = nfs_file_splice_write,
877 .check_flags = nfs_check_flags,
878 .setlease = nfs_setlease,
879};
880
881#ifdef CONFIG_NFS_V4
882static int
883nfs4_file_open(struct inode *inode, struct file *filp)
884{
885 struct nfs_open_context *ctx;
886 struct dentry *dentry = filp->f_path.dentry;
887 struct dentry *parent = NULL;
888 struct inode *dir;
889 unsigned openflags = filp->f_flags;
890 struct iattr attr;
891 int err;
892
893 BUG_ON(inode != dentry->d_inode);
894 /*
895 * If no cached dentry exists or if it's negative, NFSv4 handled the
896 * opens in ->lookup() or ->create().
897 *
898 * We only get this far for a cached positive dentry. We skipped
899 * revalidation, so handle it here by dropping the dentry and returning
900 * -EOPENSTALE. The VFS will retry the lookup/create/open.
901 */
902
903 dprintk("NFS: open file(%s/%s)\n",
904 dentry->d_parent->d_name.name,
905 dentry->d_name.name);
906
907 if ((openflags & O_ACCMODE) == 3)
908 openflags--;
909
910 /* We can't create new files here */
911 openflags &= ~(O_CREAT|O_EXCL);
912
913 parent = dget_parent(dentry);
914 dir = parent->d_inode;
915
916 ctx = alloc_nfs_open_context(filp->f_path.dentry, filp->f_mode);
917 err = PTR_ERR(ctx);
918 if (IS_ERR(ctx))
919 goto out;
920
921 attr.ia_valid = ATTR_OPEN;
922 if (openflags & O_TRUNC) {
923 attr.ia_valid |= ATTR_SIZE;
924 attr.ia_size = 0;
925 nfs_wb_all(inode);
926 }
927
928 inode = NFS_PROTO(dir)->open_context(dir, ctx, openflags, &attr);
929 if (IS_ERR(inode)) {
930 err = PTR_ERR(inode);
931 switch (err) {
932 case -EPERM:
933 case -EACCES:
934 case -EDQUOT:
935 case -ENOSPC:
936 case -EROFS:
937 goto out_put_ctx;
938 default:
939 goto out_drop;
940 }
941 }
942 iput(inode);
943 if (inode != dentry->d_inode)
944 goto out_drop;
945
946 nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
947 nfs_file_set_open_context(filp, ctx);
948 err = 0;
949
950out_put_ctx:
951 put_nfs_open_context(ctx);
952out:
953 dput(parent);
954 return err;
955
956out_drop:
957 d_drop(dentry);
958 err = -EOPENSTALE;
959 goto out_put_ctx;
960}
961
962const struct file_operations nfs4_file_operations = {
963 .llseek = nfs_file_llseek,
964 .read = do_sync_read,
965 .write = do_sync_write,
966 .aio_read = nfs_file_read,
967 .aio_write = nfs_file_write,
968 .mmap = nfs_file_mmap,
969 .open = nfs4_file_open,
970 .flush = nfs_file_flush,
971 .release = nfs_file_release,
972 .fsync = nfs_file_fsync,
973 .lock = nfs_lock,
974 .flock = nfs_flock,
975 .splice_read = nfs_file_splice_read,
976 .splice_write = nfs_file_splice_write,
977 .check_flags = nfs_check_flags,
978 .setlease = nfs_setlease,
979};
980#endif /* CONFIG_NFS_V4 */
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/nfs/file.c
4 *
5 * Copyright (C) 1992 Rick Sladkey
6 *
7 * Changes Copyright (C) 1994 by Florian La Roche
8 * - Do not copy data too often around in the kernel.
9 * - In nfs_file_read the return value of kmalloc wasn't checked.
10 * - Put in a better version of read look-ahead buffering. Original idea
11 * and implementation by Wai S Kok elekokws@ee.nus.sg.
12 *
13 * Expire cache on write to a file by Wai S Kok (Oct 1994).
14 *
15 * Total rewrite of read side for new NFS buffer cache.. Linus.
16 *
17 * nfs regular file handling functions
18 */
19
20#include <linux/module.h>
21#include <linux/time.h>
22#include <linux/kernel.h>
23#include <linux/errno.h>
24#include <linux/fcntl.h>
25#include <linux/stat.h>
26#include <linux/nfs_fs.h>
27#include <linux/nfs_mount.h>
28#include <linux/mm.h>
29#include <linux/pagemap.h>
30#include <linux/gfp.h>
31#include <linux/swap.h>
32#include <linux/compaction.h>
33
34#include <linux/uaccess.h>
35#include <linux/filelock.h>
36
37#include "delegation.h"
38#include "internal.h"
39#include "iostat.h"
40#include "fscache.h"
41#include "pnfs.h"
42
43#include "nfstrace.h"
44
45#define NFSDBG_FACILITY NFSDBG_FILE
46
47static const struct vm_operations_struct nfs_file_vm_ops;
48
49int nfs_check_flags(int flags)
50{
51 if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
52 return -EINVAL;
53
54 return 0;
55}
56EXPORT_SYMBOL_GPL(nfs_check_flags);
57
58/*
59 * Open file
60 */
61static int
62nfs_file_open(struct inode *inode, struct file *filp)
63{
64 int res;
65
66 dprintk("NFS: open file(%pD2)\n", filp);
67
68 nfs_inc_stats(inode, NFSIOS_VFSOPEN);
69 res = nfs_check_flags(filp->f_flags);
70 if (res)
71 return res;
72
73 res = nfs_open(inode, filp);
74 if (res == 0)
75 filp->f_mode |= FMODE_CAN_ODIRECT;
76 return res;
77}
78
79int
80nfs_file_release(struct inode *inode, struct file *filp)
81{
82 dprintk("NFS: release(%pD2)\n", filp);
83
84 nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
85 nfs_file_clear_open_context(filp);
86 nfs_fscache_release_file(inode, filp);
87 return 0;
88}
89EXPORT_SYMBOL_GPL(nfs_file_release);
90
91/**
92 * nfs_revalidate_file_size - Revalidate the file size
93 * @inode: pointer to inode struct
94 * @filp: pointer to struct file
95 *
96 * Revalidates the file length. This is basically a wrapper around
97 * nfs_revalidate_inode() that takes into account the fact that we may
98 * have cached writes (in which case we don't care about the server's
99 * idea of what the file length is), or O_DIRECT (in which case we
100 * shouldn't trust the cache).
101 */
102static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
103{
104 struct nfs_server *server = NFS_SERVER(inode);
105
106 if (filp->f_flags & O_DIRECT)
107 goto force_reval;
108 if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_SIZE))
109 goto force_reval;
110 return 0;
111force_reval:
112 return __nfs_revalidate_inode(server, inode);
113}
114
115loff_t nfs_file_llseek(struct file *filp, loff_t offset, int whence)
116{
117 dprintk("NFS: llseek file(%pD2, %lld, %d)\n",
118 filp, offset, whence);
119
120 /*
121 * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
122 * the cached file length
123 */
124 if (whence != SEEK_SET && whence != SEEK_CUR) {
125 struct inode *inode = filp->f_mapping->host;
126
127 int retval = nfs_revalidate_file_size(inode, filp);
128 if (retval < 0)
129 return (loff_t)retval;
130 }
131
132 return generic_file_llseek(filp, offset, whence);
133}
134EXPORT_SYMBOL_GPL(nfs_file_llseek);
135
136/*
137 * Flush all dirty pages, and check for write errors.
138 */
139static int
140nfs_file_flush(struct file *file, fl_owner_t id)
141{
142 struct inode *inode = file_inode(file);
143 errseq_t since;
144
145 dprintk("NFS: flush(%pD2)\n", file);
146
147 nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
148 if ((file->f_mode & FMODE_WRITE) == 0)
149 return 0;
150
151 /* Flush writes to the server and return any errors */
152 since = filemap_sample_wb_err(file->f_mapping);
153 nfs_wb_all(inode);
154 return filemap_check_wb_err(file->f_mapping, since);
155}
156
157ssize_t
158nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
159{
160 struct inode *inode = file_inode(iocb->ki_filp);
161 ssize_t result;
162
163 if (iocb->ki_flags & IOCB_DIRECT)
164 return nfs_file_direct_read(iocb, to, false);
165
166 dprintk("NFS: read(%pD2, %zu@%lu)\n",
167 iocb->ki_filp,
168 iov_iter_count(to), (unsigned long) iocb->ki_pos);
169
170 result = nfs_start_io_read(inode);
171 if (result)
172 return result;
173
174 result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
175 if (!result) {
176 result = generic_file_read_iter(iocb, to);
177 if (result > 0)
178 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
179 }
180 nfs_end_io_read(inode);
181 return result;
182}
183EXPORT_SYMBOL_GPL(nfs_file_read);
184
185ssize_t
186nfs_file_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe,
187 size_t len, unsigned int flags)
188{
189 struct inode *inode = file_inode(in);
190 ssize_t result;
191
192 dprintk("NFS: splice_read(%pD2, %zu@%llu)\n", in, len, *ppos);
193
194 result = nfs_start_io_read(inode);
195 if (result)
196 return result;
197
198 result = nfs_revalidate_mapping(inode, in->f_mapping);
199 if (!result) {
200 result = filemap_splice_read(in, ppos, pipe, len, flags);
201 if (result > 0)
202 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
203 }
204 nfs_end_io_read(inode);
205 return result;
206}
207EXPORT_SYMBOL_GPL(nfs_file_splice_read);
208
209int
210nfs_file_mmap(struct file *file, struct vm_area_struct *vma)
211{
212 struct inode *inode = file_inode(file);
213 int status;
214
215 dprintk("NFS: mmap(%pD2)\n", file);
216
217 /* Note: generic_file_mmap() returns ENOSYS on nommu systems
218 * so we call that before revalidating the mapping
219 */
220 status = generic_file_mmap(file, vma);
221 if (!status) {
222 vma->vm_ops = &nfs_file_vm_ops;
223 status = nfs_revalidate_mapping(inode, file->f_mapping);
224 }
225 return status;
226}
227EXPORT_SYMBOL_GPL(nfs_file_mmap);
228
229/*
230 * Flush any dirty pages for this process, and check for write errors.
231 * The return status from this call provides a reliable indication of
232 * whether any write errors occurred for this process.
233 */
234static int
235nfs_file_fsync_commit(struct file *file, int datasync)
236{
237 struct inode *inode = file_inode(file);
238 int ret, ret2;
239
240 dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
241
242 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
243 ret = nfs_commit_inode(inode, FLUSH_SYNC);
244 ret2 = file_check_and_advance_wb_err(file);
245 if (ret2 < 0)
246 return ret2;
247 return ret;
248}
249
250int
251nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
252{
253 struct inode *inode = file_inode(file);
254 struct nfs_inode *nfsi = NFS_I(inode);
255 long save_nredirtied = atomic_long_read(&nfsi->redirtied_pages);
256 long nredirtied;
257 int ret;
258
259 trace_nfs_fsync_enter(inode);
260
261 for (;;) {
262 ret = file_write_and_wait_range(file, start, end);
263 if (ret != 0)
264 break;
265 ret = nfs_file_fsync_commit(file, datasync);
266 if (ret != 0)
267 break;
268 ret = pnfs_sync_inode(inode, !!datasync);
269 if (ret != 0)
270 break;
271 nredirtied = atomic_long_read(&nfsi->redirtied_pages);
272 if (nredirtied == save_nredirtied)
273 break;
274 save_nredirtied = nredirtied;
275 }
276
277 trace_nfs_fsync_exit(inode, ret);
278 return ret;
279}
280EXPORT_SYMBOL_GPL(nfs_file_fsync);
281
282/*
283 * Decide whether a read/modify/write cycle may be more efficient
284 * then a modify/write/read cycle when writing to a page in the
285 * page cache.
286 *
287 * Some pNFS layout drivers can only read/write at a certain block
288 * granularity like all block devices and therefore we must perform
289 * read/modify/write whenever a page hasn't read yet and the data
290 * to be written there is not aligned to a block boundary and/or
291 * smaller than the block size.
292 *
293 * The modify/write/read cycle may occur if a page is read before
294 * being completely filled by the writer. In this situation, the
295 * page must be completely written to stable storage on the server
296 * before it can be refilled by reading in the page from the server.
297 * This can lead to expensive, small, FILE_SYNC mode writes being
298 * done.
299 *
300 * It may be more efficient to read the page first if the file is
301 * open for reading in addition to writing, the page is not marked
302 * as Uptodate, it is not dirty or waiting to be committed,
303 * indicating that it was previously allocated and then modified,
304 * that there were valid bytes of data in that range of the file,
305 * and that the new data won't completely replace the old data in
306 * that range of the file.
307 */
308static bool nfs_folio_is_full_write(struct folio *folio, loff_t pos,
309 unsigned int len)
310{
311 unsigned int pglen = nfs_folio_length(folio);
312 unsigned int offset = offset_in_folio(folio, pos);
313 unsigned int end = offset + len;
314
315 return !pglen || (end >= pglen && !offset);
316}
317
318static bool nfs_want_read_modify_write(struct file *file, struct folio *folio,
319 loff_t pos, unsigned int len)
320{
321 /*
322 * Up-to-date pages, those with ongoing or full-page write
323 * don't need read/modify/write
324 */
325 if (folio_test_uptodate(folio) || folio_test_private(folio) ||
326 nfs_folio_is_full_write(folio, pos, len))
327 return false;
328
329 if (pnfs_ld_read_whole_page(file_inode(file)))
330 return true;
331 /* Open for reading too? */
332 if (file->f_mode & FMODE_READ)
333 return true;
334 return false;
335}
336
337/*
338 * This does the "real" work of the write. We must allocate and lock the
339 * page to be sent back to the generic routine, which then copies the
340 * data from user space.
341 *
342 * If the writer ends up delaying the write, the writer needs to
343 * increment the page use counts until he is done with the page.
344 */
345static int nfs_write_begin(struct file *file, struct address_space *mapping,
346 loff_t pos, unsigned len, struct folio **foliop,
347 void **fsdata)
348{
349 fgf_t fgp = FGP_WRITEBEGIN;
350 struct folio *folio;
351 int once_thru = 0;
352 int ret;
353
354 dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
355 file, mapping->host->i_ino, len, (long long) pos);
356
357 fgp |= fgf_set_order(len);
358start:
359 folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, fgp,
360 mapping_gfp_mask(mapping));
361 if (IS_ERR(folio))
362 return PTR_ERR(folio);
363 *foliop = folio;
364
365 ret = nfs_flush_incompatible(file, folio);
366 if (ret) {
367 folio_unlock(folio);
368 folio_put(folio);
369 } else if (!once_thru &&
370 nfs_want_read_modify_write(file, folio, pos, len)) {
371 once_thru = 1;
372 ret = nfs_read_folio(file, folio);
373 folio_put(folio);
374 if (!ret)
375 goto start;
376 }
377 return ret;
378}
379
380static int nfs_write_end(struct file *file, struct address_space *mapping,
381 loff_t pos, unsigned len, unsigned copied,
382 struct folio *folio, void *fsdata)
383{
384 struct nfs_open_context *ctx = nfs_file_open_context(file);
385 unsigned offset = offset_in_folio(folio, pos);
386 int status;
387
388 dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
389 file, mapping->host->i_ino, len, (long long) pos);
390
391 /*
392 * Zero any uninitialised parts of the page, and then mark the page
393 * as up to date if it turns out that we're extending the file.
394 */
395 if (!folio_test_uptodate(folio)) {
396 size_t fsize = folio_size(folio);
397 unsigned pglen = nfs_folio_length(folio);
398 unsigned end = offset + copied;
399
400 if (pglen == 0) {
401 folio_zero_segments(folio, 0, offset, end, fsize);
402 folio_mark_uptodate(folio);
403 } else if (end >= pglen) {
404 folio_zero_segment(folio, end, fsize);
405 if (offset == 0)
406 folio_mark_uptodate(folio);
407 } else
408 folio_zero_segment(folio, pglen, fsize);
409 }
410
411 status = nfs_update_folio(file, folio, offset, copied);
412
413 folio_unlock(folio);
414 folio_put(folio);
415
416 if (status < 0)
417 return status;
418 NFS_I(mapping->host)->write_io += copied;
419
420 if (nfs_ctx_key_to_expire(ctx, mapping->host))
421 nfs_wb_all(mapping->host);
422
423 return copied;
424}
425
426/*
427 * Partially or wholly invalidate a page
428 * - Release the private state associated with a page if undergoing complete
429 * page invalidation
430 * - Called if either PG_private or PG_fscache is set on the page
431 * - Caller holds page lock
432 */
433static void nfs_invalidate_folio(struct folio *folio, size_t offset,
434 size_t length)
435{
436 struct inode *inode = folio->mapping->host;
437 dfprintk(PAGECACHE, "NFS: invalidate_folio(%lu, %zu, %zu)\n",
438 folio->index, offset, length);
439
440 if (offset != 0 || length < folio_size(folio))
441 return;
442 /* Cancel any unstarted writes on this page */
443 nfs_wb_folio_cancel(inode, folio);
444 folio_wait_private_2(folio); /* [DEPRECATED] */
445 trace_nfs_invalidate_folio(inode, folio_pos(folio) + offset, length);
446}
447
448/*
449 * Attempt to release the private state associated with a folio
450 * - Called if either private or fscache flags are set on the folio
451 * - Caller holds folio lock
452 * - Return true (may release folio) or false (may not)
453 */
454static bool nfs_release_folio(struct folio *folio, gfp_t gfp)
455{
456 dfprintk(PAGECACHE, "NFS: release_folio(%p)\n", folio);
457
458 /* If the private flag is set, then the folio is not freeable */
459 if (folio_test_private(folio)) {
460 if ((current_gfp_context(gfp) & GFP_KERNEL) != GFP_KERNEL ||
461 current_is_kswapd() || current_is_kcompactd())
462 return false;
463 if (nfs_wb_folio(folio->mapping->host, folio) < 0)
464 return false;
465 }
466 return nfs_fscache_release_folio(folio, gfp);
467}
468
469static void nfs_check_dirty_writeback(struct folio *folio,
470 bool *dirty, bool *writeback)
471{
472 struct nfs_inode *nfsi;
473 struct address_space *mapping = folio->mapping;
474
475 /*
476 * Check if an unstable folio is currently being committed and
477 * if so, have the VM treat it as if the folio is under writeback
478 * so it will not block due to folios that will shortly be freeable.
479 */
480 nfsi = NFS_I(mapping->host);
481 if (atomic_read(&nfsi->commit_info.rpcs_out)) {
482 *writeback = true;
483 return;
484 }
485
486 /*
487 * If the private flag is set, then the folio is not freeable
488 * and as the inode is not being committed, it's not going to
489 * be cleaned in the near future so treat it as dirty
490 */
491 if (folio_test_private(folio))
492 *dirty = true;
493}
494
495/*
496 * Attempt to clear the private state associated with a page when an error
497 * occurs that requires the cached contents of an inode to be written back or
498 * destroyed
499 * - Called if either PG_private or fscache is set on the page
500 * - Caller holds page lock
501 * - Return 0 if successful, -error otherwise
502 */
503static int nfs_launder_folio(struct folio *folio)
504{
505 struct inode *inode = folio->mapping->host;
506 int ret;
507
508 dfprintk(PAGECACHE, "NFS: launder_folio(%ld, %llu)\n",
509 inode->i_ino, folio_pos(folio));
510
511 folio_wait_private_2(folio); /* [DEPRECATED] */
512 ret = nfs_wb_folio(inode, folio);
513 trace_nfs_launder_folio_done(inode, folio_pos(folio),
514 folio_size(folio), ret);
515 return ret;
516}
517
518static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
519 sector_t *span)
520{
521 unsigned long blocks;
522 long long isize;
523 int ret;
524 struct inode *inode = file_inode(file);
525 struct rpc_clnt *clnt = NFS_CLIENT(inode);
526 struct nfs_client *cl = NFS_SERVER(inode)->nfs_client;
527
528 spin_lock(&inode->i_lock);
529 blocks = inode->i_blocks;
530 isize = inode->i_size;
531 spin_unlock(&inode->i_lock);
532 if (blocks*512 < isize) {
533 pr_warn("swap activate: swapfile has holes\n");
534 return -EINVAL;
535 }
536
537 ret = rpc_clnt_swap_activate(clnt);
538 if (ret)
539 return ret;
540 ret = add_swap_extent(sis, 0, sis->max, 0);
541 if (ret < 0) {
542 rpc_clnt_swap_deactivate(clnt);
543 return ret;
544 }
545
546 *span = sis->pages;
547
548 if (cl->rpc_ops->enable_swap)
549 cl->rpc_ops->enable_swap(inode);
550
551 sis->flags |= SWP_FS_OPS;
552 return ret;
553}
554
555static void nfs_swap_deactivate(struct file *file)
556{
557 struct inode *inode = file_inode(file);
558 struct rpc_clnt *clnt = NFS_CLIENT(inode);
559 struct nfs_client *cl = NFS_SERVER(inode)->nfs_client;
560
561 rpc_clnt_swap_deactivate(clnt);
562 if (cl->rpc_ops->disable_swap)
563 cl->rpc_ops->disable_swap(file_inode(file));
564}
565
566const struct address_space_operations nfs_file_aops = {
567 .read_folio = nfs_read_folio,
568 .readahead = nfs_readahead,
569 .dirty_folio = filemap_dirty_folio,
570 .writepages = nfs_writepages,
571 .write_begin = nfs_write_begin,
572 .write_end = nfs_write_end,
573 .invalidate_folio = nfs_invalidate_folio,
574 .release_folio = nfs_release_folio,
575 .migrate_folio = nfs_migrate_folio,
576 .launder_folio = nfs_launder_folio,
577 .is_dirty_writeback = nfs_check_dirty_writeback,
578 .error_remove_folio = generic_error_remove_folio,
579 .swap_activate = nfs_swap_activate,
580 .swap_deactivate = nfs_swap_deactivate,
581 .swap_rw = nfs_swap_rw,
582};
583
584/*
585 * Notification that a PTE pointing to an NFS page is about to be made
586 * writable, implying that someone is about to modify the page through a
587 * shared-writable mapping
588 */
589static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf)
590{
591 struct file *filp = vmf->vma->vm_file;
592 struct inode *inode = file_inode(filp);
593 unsigned pagelen;
594 vm_fault_t ret = VM_FAULT_NOPAGE;
595 struct address_space *mapping;
596 struct folio *folio = page_folio(vmf->page);
597
598 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
599 filp, filp->f_mapping->host->i_ino,
600 (long long)folio_pos(folio));
601
602 sb_start_pagefault(inode->i_sb);
603
604 /* make sure the cache has finished storing the page */
605 if (folio_test_private_2(folio) && /* [DEPRECATED] */
606 folio_wait_private_2_killable(folio) < 0) {
607 ret = VM_FAULT_RETRY;
608 goto out;
609 }
610
611 wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
612 nfs_wait_bit_killable,
613 TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
614
615 folio_lock(folio);
616 mapping = folio->mapping;
617 if (mapping != inode->i_mapping)
618 goto out_unlock;
619
620 folio_wait_writeback(folio);
621
622 pagelen = nfs_folio_length(folio);
623 if (pagelen == 0)
624 goto out_unlock;
625
626 ret = VM_FAULT_LOCKED;
627 if (nfs_flush_incompatible(filp, folio) == 0 &&
628 nfs_update_folio(filp, folio, 0, pagelen) == 0)
629 goto out;
630
631 ret = VM_FAULT_SIGBUS;
632out_unlock:
633 folio_unlock(folio);
634out:
635 sb_end_pagefault(inode->i_sb);
636 return ret;
637}
638
639static const struct vm_operations_struct nfs_file_vm_ops = {
640 .fault = filemap_fault,
641 .map_pages = filemap_map_pages,
642 .page_mkwrite = nfs_vm_page_mkwrite,
643};
644
645ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
646{
647 struct file *file = iocb->ki_filp;
648 struct inode *inode = file_inode(file);
649 unsigned int mntflags = NFS_SERVER(inode)->flags;
650 ssize_t result, written;
651 errseq_t since;
652 int error;
653
654 result = nfs_key_timeout_notify(file, inode);
655 if (result)
656 return result;
657
658 if (iocb->ki_flags & IOCB_DIRECT)
659 return nfs_file_direct_write(iocb, from, false);
660
661 dprintk("NFS: write(%pD2, %zu@%Ld)\n",
662 file, iov_iter_count(from), (long long) iocb->ki_pos);
663
664 if (IS_SWAPFILE(inode))
665 goto out_swapfile;
666 /*
667 * O_APPEND implies that we must revalidate the file length.
668 */
669 if (iocb->ki_flags & IOCB_APPEND || iocb->ki_pos > i_size_read(inode)) {
670 result = nfs_revalidate_file_size(inode, file);
671 if (result)
672 return result;
673 }
674
675 nfs_clear_invalid_mapping(file->f_mapping);
676
677 since = filemap_sample_wb_err(file->f_mapping);
678 error = nfs_start_io_write(inode);
679 if (error)
680 return error;
681 result = generic_write_checks(iocb, from);
682 if (result > 0)
683 result = generic_perform_write(iocb, from);
684 nfs_end_io_write(inode);
685 if (result <= 0)
686 goto out;
687
688 written = result;
689 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
690
691 if (mntflags & NFS_MOUNT_WRITE_EAGER) {
692 result = filemap_fdatawrite_range(file->f_mapping,
693 iocb->ki_pos - written,
694 iocb->ki_pos - 1);
695 if (result < 0)
696 goto out;
697 }
698 if (mntflags & NFS_MOUNT_WRITE_WAIT) {
699 filemap_fdatawait_range(file->f_mapping,
700 iocb->ki_pos - written,
701 iocb->ki_pos - 1);
702 }
703 result = generic_write_sync(iocb, written);
704 if (result < 0)
705 return result;
706
707out:
708 /* Return error values */
709 error = filemap_check_wb_err(file->f_mapping, since);
710 switch (error) {
711 default:
712 break;
713 case -EDQUOT:
714 case -EFBIG:
715 case -ENOSPC:
716 nfs_wb_all(inode);
717 error = file_check_and_advance_wb_err(file);
718 if (error < 0)
719 result = error;
720 }
721 return result;
722
723out_swapfile:
724 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
725 return -ETXTBSY;
726}
727EXPORT_SYMBOL_GPL(nfs_file_write);
728
729static int
730do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
731{
732 struct inode *inode = filp->f_mapping->host;
733 int status = 0;
734 unsigned int saved_type = fl->c.flc_type;
735
736 /* Try local locking first */
737 posix_test_lock(filp, fl);
738 if (fl->c.flc_type != F_UNLCK) {
739 /* found a conflict */
740 goto out;
741 }
742 fl->c.flc_type = saved_type;
743
744 if (nfs_have_read_or_write_delegation(inode))
745 goto out_noconflict;
746
747 if (is_local)
748 goto out_noconflict;
749
750 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
751out:
752 return status;
753out_noconflict:
754 fl->c.flc_type = F_UNLCK;
755 goto out;
756}
757
758static int
759do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
760{
761 struct inode *inode = filp->f_mapping->host;
762 struct nfs_lock_context *l_ctx;
763 int status;
764
765 /*
766 * Flush all pending writes before doing anything
767 * with locks..
768 */
769 nfs_wb_all(inode);
770
771 l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
772 if (!IS_ERR(l_ctx)) {
773 status = nfs_iocounter_wait(l_ctx);
774 nfs_put_lock_context(l_ctx);
775 /* NOTE: special case
776 * If we're signalled while cleaning up locks on process exit, we
777 * still need to complete the unlock.
778 */
779 if (status < 0 && !(fl->c.flc_flags & FL_CLOSE))
780 return status;
781 }
782
783 /*
784 * Use local locking if mounted with "-onolock" or with appropriate
785 * "-olocal_lock="
786 */
787 if (!is_local)
788 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
789 else
790 status = locks_lock_file_wait(filp, fl);
791 return status;
792}
793
794static int
795do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
796{
797 struct inode *inode = filp->f_mapping->host;
798 int status;
799
800 /*
801 * Flush all pending writes before doing anything
802 * with locks..
803 */
804 status = nfs_sync_mapping(filp->f_mapping);
805 if (status != 0)
806 goto out;
807
808 /*
809 * Use local locking if mounted with "-onolock" or with appropriate
810 * "-olocal_lock="
811 */
812 if (!is_local)
813 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
814 else
815 status = locks_lock_file_wait(filp, fl);
816 if (status < 0)
817 goto out;
818
819 /*
820 * Invalidate cache to prevent missing any changes. If
821 * the file is mapped, clear the page cache as well so
822 * those mappings will be loaded.
823 *
824 * This makes locking act as a cache coherency point.
825 */
826 nfs_sync_mapping(filp->f_mapping);
827 if (!nfs_have_read_or_write_delegation(inode)) {
828 nfs_zap_caches(inode);
829 if (mapping_mapped(filp->f_mapping))
830 nfs_revalidate_mapping(inode, filp->f_mapping);
831 }
832out:
833 return status;
834}
835
836/*
837 * Lock a (portion of) a file
838 */
839int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
840{
841 struct inode *inode = filp->f_mapping->host;
842 int ret = -ENOLCK;
843 int is_local = 0;
844
845 dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n",
846 filp, fl->c.flc_type, fl->c.flc_flags,
847 (long long)fl->fl_start, (long long)fl->fl_end);
848
849 nfs_inc_stats(inode, NFSIOS_VFSLOCK);
850
851 if (fl->c.flc_flags & FL_RECLAIM)
852 return -ENOGRACE;
853
854 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
855 is_local = 1;
856
857 if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
858 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
859 if (ret < 0)
860 goto out_err;
861 }
862
863 if (IS_GETLK(cmd))
864 ret = do_getlk(filp, cmd, fl, is_local);
865 else if (lock_is_unlock(fl))
866 ret = do_unlk(filp, cmd, fl, is_local);
867 else
868 ret = do_setlk(filp, cmd, fl, is_local);
869out_err:
870 return ret;
871}
872EXPORT_SYMBOL_GPL(nfs_lock);
873
874/*
875 * Lock a (portion of) a file
876 */
877int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
878{
879 struct inode *inode = filp->f_mapping->host;
880 int is_local = 0;
881
882 dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n",
883 filp, fl->c.flc_type, fl->c.flc_flags);
884
885 if (!(fl->c.flc_flags & FL_FLOCK))
886 return -ENOLCK;
887
888 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
889 is_local = 1;
890
891 /* We're simulating flock() locks using posix locks on the server */
892 if (lock_is_unlock(fl))
893 return do_unlk(filp, cmd, fl, is_local);
894 return do_setlk(filp, cmd, fl, is_local);
895}
896EXPORT_SYMBOL_GPL(nfs_flock);
897
898const struct file_operations nfs_file_operations = {
899 .llseek = nfs_file_llseek,
900 .read_iter = nfs_file_read,
901 .write_iter = nfs_file_write,
902 .mmap = nfs_file_mmap,
903 .open = nfs_file_open,
904 .flush = nfs_file_flush,
905 .release = nfs_file_release,
906 .fsync = nfs_file_fsync,
907 .lock = nfs_lock,
908 .flock = nfs_flock,
909 .splice_read = nfs_file_splice_read,
910 .splice_write = iter_file_splice_write,
911 .check_flags = nfs_check_flags,
912 .setlease = simple_nosetlease,
913};
914EXPORT_SYMBOL_GPL(nfs_file_operations);