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
47 static const struct vm_operations_struct nfs_file_vm_ops;
48
nfs_check_flags(int flags)49 int 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 }
56 EXPORT_SYMBOL_GPL(nfs_check_flags);
57
58 /*
59 * Open file
60 */
61 static int
nfs_file_open(struct inode * inode,struct file * filp)62 nfs_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
79 int
nfs_file_release(struct inode * inode,struct file * filp)80 nfs_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 }
89 EXPORT_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 */
nfs_revalidate_file_size(struct inode * inode,struct file * filp)102 static 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;
111 force_reval:
112 return __nfs_revalidate_inode(server, inode);
113 }
114
nfs_file_llseek(struct file * filp,loff_t offset,int whence)115 loff_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 }
134 EXPORT_SYMBOL_GPL(nfs_file_llseek);
135
136 /*
137 * Flush all dirty pages, and check for write errors.
138 */
139 static int
nfs_file_flush(struct file * file,fl_owner_t id)140 nfs_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
157 ssize_t
nfs_file_read(struct kiocb * iocb,struct iov_iter * to)158 nfs_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 }
183 EXPORT_SYMBOL_GPL(nfs_file_read);
184
185 ssize_t
nfs_file_splice_read(struct file * in,loff_t * ppos,struct pipe_inode_info * pipe,size_t len,unsigned int flags)186 nfs_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 }
207 EXPORT_SYMBOL_GPL(nfs_file_splice_read);
208
209 int
nfs_file_mmap(struct file * file,struct vm_area_struct * vma)210 nfs_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 }
227 EXPORT_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 */
234 static int
nfs_file_fsync_commit(struct file * file,int datasync)235 nfs_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
250 int
nfs_file_fsync(struct file * file,loff_t start,loff_t end,int datasync)251 nfs_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 }
280 EXPORT_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 */
nfs_folio_is_full_write(struct folio * folio,loff_t pos,unsigned int len)308 static 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
nfs_want_read_modify_write(struct file * file,struct folio * folio,loff_t pos,unsigned int len)318 static 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 */
nfs_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct folio ** foliop,void ** fsdata)345 static 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);
358 start:
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
nfs_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)380 static 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 */
nfs_invalidate_folio(struct folio * folio,size_t offset,size_t length)433 static 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 */
nfs_release_folio(struct folio * folio,gfp_t gfp)454 static 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
nfs_check_dirty_writeback(struct folio * folio,bool * dirty,bool * writeback)469 static 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 */
nfs_launder_folio(struct folio * folio)503 static 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
nfs_swap_activate(struct swap_info_struct * sis,struct file * file,sector_t * span)518 static 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
nfs_swap_deactivate(struct file * file)555 static 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
566 const 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 */
nfs_vm_page_mkwrite(struct vm_fault * vmf)589 static 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;
632 out_unlock:
633 folio_unlock(folio);
634 out:
635 sb_end_pagefault(inode->i_sb);
636 return ret;
637 }
638
639 static 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
nfs_file_write(struct kiocb * iocb,struct iov_iter * from)645 ssize_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
707 out:
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
723 out_swapfile:
724 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
725 return -ETXTBSY;
726 }
727 EXPORT_SYMBOL_GPL(nfs_file_write);
728
729 static int
do_getlk(struct file * filp,int cmd,struct file_lock * fl,int is_local)730 do_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);
751 out:
752 return status;
753 out_noconflict:
754 fl->c.flc_type = F_UNLCK;
755 goto out;
756 }
757
758 static int
do_unlk(struct file * filp,int cmd,struct file_lock * fl,int is_local)759 do_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
794 static int
do_setlk(struct file * filp,int cmd,struct file_lock * fl,int is_local)795 do_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 }
832 out:
833 return status;
834 }
835
836 /*
837 * Lock a (portion of) a file
838 */
nfs_lock(struct file * filp,int cmd,struct file_lock * fl)839 int 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);
869 out_err:
870 return ret;
871 }
872 EXPORT_SYMBOL_GPL(nfs_lock);
873
874 /*
875 * Lock a (portion of) a file
876 */
nfs_flock(struct file * filp,int cmd,struct file_lock * fl)877 int 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 }
896 EXPORT_SYMBOL_GPL(nfs_flock);
897
898 const 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 };
914 EXPORT_SYMBOL_GPL(nfs_file_operations);
915