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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#include <asm/system.h>
34
35#include "delegation.h"
36#include "internal.h"
37#include "iostat.h"
38#include "fscache.h"
39#include "pnfs.h"
40
41#define NFSDBG_FACILITY NFSDBG_FILE
42
43static int nfs_file_open(struct inode *, struct file *);
44static int nfs_file_release(struct inode *, struct file *);
45static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
46static int nfs_file_mmap(struct file *, struct vm_area_struct *);
47static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
48 struct pipe_inode_info *pipe,
49 size_t count, unsigned int flags);
50static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
51 unsigned long nr_segs, loff_t pos);
52static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
53 struct file *filp, loff_t *ppos,
54 size_t count, unsigned int flags);
55static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
56 unsigned long nr_segs, loff_t pos);
57static int nfs_file_flush(struct file *, fl_owner_t id);
58static int nfs_file_fsync(struct file *, loff_t, loff_t, int datasync);
59static int nfs_check_flags(int flags);
60static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
61static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
62static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
63
64static const struct vm_operations_struct nfs_file_vm_ops;
65
66const struct file_operations nfs_file_operations = {
67 .llseek = nfs_file_llseek,
68 .read = do_sync_read,
69 .write = do_sync_write,
70 .aio_read = nfs_file_read,
71 .aio_write = nfs_file_write,
72 .mmap = nfs_file_mmap,
73 .open = nfs_file_open,
74 .flush = nfs_file_flush,
75 .release = nfs_file_release,
76 .fsync = nfs_file_fsync,
77 .lock = nfs_lock,
78 .flock = nfs_flock,
79 .splice_read = nfs_file_splice_read,
80 .splice_write = nfs_file_splice_write,
81 .check_flags = nfs_check_flags,
82 .setlease = nfs_setlease,
83};
84
85const struct inode_operations nfs_file_inode_operations = {
86 .permission = nfs_permission,
87 .getattr = nfs_getattr,
88 .setattr = nfs_setattr,
89};
90
91#ifdef CONFIG_NFS_V3
92const struct inode_operations nfs3_file_inode_operations = {
93 .permission = nfs_permission,
94 .getattr = nfs_getattr,
95 .setattr = nfs_setattr,
96 .listxattr = nfs3_listxattr,
97 .getxattr = nfs3_getxattr,
98 .setxattr = nfs3_setxattr,
99 .removexattr = nfs3_removexattr,
100};
101#endif /* CONFIG_NFS_v3 */
102
103/* Hack for future NFS swap support */
104#ifndef IS_SWAPFILE
105# define IS_SWAPFILE(inode) (0)
106#endif
107
108static int nfs_check_flags(int flags)
109{
110 if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
111 return -EINVAL;
112
113 return 0;
114}
115
116/*
117 * Open file
118 */
119static int
120nfs_file_open(struct inode *inode, struct file *filp)
121{
122 int res;
123
124 dprintk("NFS: open file(%s/%s)\n",
125 filp->f_path.dentry->d_parent->d_name.name,
126 filp->f_path.dentry->d_name.name);
127
128 nfs_inc_stats(inode, NFSIOS_VFSOPEN);
129 res = nfs_check_flags(filp->f_flags);
130 if (res)
131 return res;
132
133 res = nfs_open(inode, filp);
134 return res;
135}
136
137static int
138nfs_file_release(struct inode *inode, struct file *filp)
139{
140 struct dentry *dentry = filp->f_path.dentry;
141
142 dprintk("NFS: release(%s/%s)\n",
143 dentry->d_parent->d_name.name,
144 dentry->d_name.name);
145
146 nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
147 return nfs_release(inode, filp);
148}
149
150/**
151 * nfs_revalidate_size - Revalidate the file size
152 * @inode - pointer to inode struct
153 * @file - pointer to struct file
154 *
155 * Revalidates the file length. This is basically a wrapper around
156 * nfs_revalidate_inode() that takes into account the fact that we may
157 * have cached writes (in which case we don't care about the server's
158 * idea of what the file length is), or O_DIRECT (in which case we
159 * shouldn't trust the cache).
160 */
161static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
162{
163 struct nfs_server *server = NFS_SERVER(inode);
164 struct nfs_inode *nfsi = NFS_I(inode);
165
166 if (nfs_have_delegated_attributes(inode))
167 goto out_noreval;
168
169 if (filp->f_flags & O_DIRECT)
170 goto force_reval;
171 if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
172 goto force_reval;
173 if (nfs_attribute_timeout(inode))
174 goto force_reval;
175out_noreval:
176 return 0;
177force_reval:
178 return __nfs_revalidate_inode(server, inode);
179}
180
181static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
182{
183 loff_t loff;
184
185 dprintk("NFS: llseek file(%s/%s, %lld, %d)\n",
186 filp->f_path.dentry->d_parent->d_name.name,
187 filp->f_path.dentry->d_name.name,
188 offset, origin);
189
190 /*
191 * origin == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
192 * the cached file length
193 */
194 if (origin != SEEK_SET || origin != SEEK_CUR) {
195 struct inode *inode = filp->f_mapping->host;
196
197 int retval = nfs_revalidate_file_size(inode, filp);
198 if (retval < 0)
199 return (loff_t)retval;
200
201 spin_lock(&inode->i_lock);
202 loff = generic_file_llseek_unlocked(filp, offset, origin);
203 spin_unlock(&inode->i_lock);
204 } else
205 loff = generic_file_llseek_unlocked(filp, offset, origin);
206 return loff;
207}
208
209/*
210 * Flush all dirty pages, and check for write errors.
211 */
212static int
213nfs_file_flush(struct file *file, fl_owner_t id)
214{
215 struct dentry *dentry = file->f_path.dentry;
216 struct inode *inode = dentry->d_inode;
217
218 dprintk("NFS: flush(%s/%s)\n",
219 dentry->d_parent->d_name.name,
220 dentry->d_name.name);
221
222 nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
223 if ((file->f_mode & FMODE_WRITE) == 0)
224 return 0;
225
226 /* Flush writes to the server and return any errors */
227 return vfs_fsync(file, 0);
228}
229
230static ssize_t
231nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
232 unsigned long nr_segs, loff_t pos)
233{
234 struct dentry * dentry = iocb->ki_filp->f_path.dentry;
235 struct inode * inode = dentry->d_inode;
236 ssize_t result;
237 size_t count = iov_length(iov, nr_segs);
238
239 if (iocb->ki_filp->f_flags & O_DIRECT)
240 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
241
242 dprintk("NFS: read(%s/%s, %lu@%lu)\n",
243 dentry->d_parent->d_name.name, dentry->d_name.name,
244 (unsigned long) count, (unsigned long) pos);
245
246 result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
247 if (!result) {
248 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
249 if (result > 0)
250 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
251 }
252 return result;
253}
254
255static ssize_t
256nfs_file_splice_read(struct file *filp, loff_t *ppos,
257 struct pipe_inode_info *pipe, size_t count,
258 unsigned int flags)
259{
260 struct dentry *dentry = filp->f_path.dentry;
261 struct inode *inode = dentry->d_inode;
262 ssize_t res;
263
264 dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n",
265 dentry->d_parent->d_name.name, dentry->d_name.name,
266 (unsigned long) count, (unsigned long long) *ppos);
267
268 res = nfs_revalidate_mapping(inode, filp->f_mapping);
269 if (!res) {
270 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
271 if (res > 0)
272 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, res);
273 }
274 return res;
275}
276
277static int
278nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
279{
280 struct dentry *dentry = file->f_path.dentry;
281 struct inode *inode = dentry->d_inode;
282 int status;
283
284 dprintk("NFS: mmap(%s/%s)\n",
285 dentry->d_parent->d_name.name, dentry->d_name.name);
286
287 /* Note: generic_file_mmap() returns ENOSYS on nommu systems
288 * so we call that before revalidating the mapping
289 */
290 status = generic_file_mmap(file, vma);
291 if (!status) {
292 vma->vm_ops = &nfs_file_vm_ops;
293 status = nfs_revalidate_mapping(inode, file->f_mapping);
294 }
295 return status;
296}
297
298/*
299 * Flush any dirty pages for this process, and check for write errors.
300 * The return status from this call provides a reliable indication of
301 * whether any write errors occurred for this process.
302 *
303 * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
304 * disk, but it retrieves and clears ctx->error after synching, despite
305 * the two being set at the same time in nfs_context_set_write_error().
306 * This is because the former is used to notify the _next_ call to
307 * nfs_file_write() that a write error occurred, and hence cause it to
308 * fall back to doing a synchronous write.
309 */
310static int
311nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
312{
313 struct dentry *dentry = file->f_path.dentry;
314 struct nfs_open_context *ctx = nfs_file_open_context(file);
315 struct inode *inode = dentry->d_inode;
316 int have_error, status;
317 int ret = 0;
318
319 dprintk("NFS: fsync file(%s/%s) datasync %d\n",
320 dentry->d_parent->d_name.name, dentry->d_name.name,
321 datasync);
322
323 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
324 if (ret)
325 return ret;
326 mutex_lock(&inode->i_mutex);
327
328 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
329 have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
330 status = nfs_commit_inode(inode, FLUSH_SYNC);
331 have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
332 if (have_error)
333 ret = xchg(&ctx->error, 0);
334 if (!ret && status < 0)
335 ret = status;
336 if (!ret && !datasync)
337 /* application has asked for meta-data sync */
338 ret = pnfs_layoutcommit_inode(inode, true);
339 mutex_unlock(&inode->i_mutex);
340 return ret;
341}
342
343/*
344 * Decide whether a read/modify/write cycle may be more efficient
345 * then a modify/write/read cycle when writing to a page in the
346 * page cache.
347 *
348 * The modify/write/read cycle may occur if a page is read before
349 * being completely filled by the writer. In this situation, the
350 * page must be completely written to stable storage on the server
351 * before it can be refilled by reading in the page from the server.
352 * This can lead to expensive, small, FILE_SYNC mode writes being
353 * done.
354 *
355 * It may be more efficient to read the page first if the file is
356 * open for reading in addition to writing, the page is not marked
357 * as Uptodate, it is not dirty or waiting to be committed,
358 * indicating that it was previously allocated and then modified,
359 * that there were valid bytes of data in that range of the file,
360 * and that the new data won't completely replace the old data in
361 * that range of the file.
362 */
363static int nfs_want_read_modify_write(struct file *file, struct page *page,
364 loff_t pos, unsigned len)
365{
366 unsigned int pglen = nfs_page_length(page);
367 unsigned int offset = pos & (PAGE_CACHE_SIZE - 1);
368 unsigned int end = offset + len;
369
370 if ((file->f_mode & FMODE_READ) && /* open for read? */
371 !PageUptodate(page) && /* Uptodate? */
372 !PagePrivate(page) && /* i/o request already? */
373 pglen && /* valid bytes of file? */
374 (end < pglen || offset)) /* replace all valid bytes? */
375 return 1;
376 return 0;
377}
378
379/*
380 * This does the "real" work of the write. We must allocate and lock the
381 * page to be sent back to the generic routine, which then copies the
382 * data from user space.
383 *
384 * If the writer ends up delaying the write, the writer needs to
385 * increment the page use counts until he is done with the page.
386 */
387static int nfs_write_begin(struct file *file, struct address_space *mapping,
388 loff_t pos, unsigned len, unsigned flags,
389 struct page **pagep, void **fsdata)
390{
391 int ret;
392 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
393 struct page *page;
394 int once_thru = 0;
395
396 dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n",
397 file->f_path.dentry->d_parent->d_name.name,
398 file->f_path.dentry->d_name.name,
399 mapping->host->i_ino, len, (long long) pos);
400
401start:
402 /*
403 * Prevent starvation issues if someone is doing a consistency
404 * sync-to-disk
405 */
406 ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
407 nfs_wait_bit_killable, TASK_KILLABLE);
408 if (ret)
409 return ret;
410
411 page = grab_cache_page_write_begin(mapping, index, flags);
412 if (!page)
413 return -ENOMEM;
414 *pagep = page;
415
416 ret = nfs_flush_incompatible(file, page);
417 if (ret) {
418 unlock_page(page);
419 page_cache_release(page);
420 } else if (!once_thru &&
421 nfs_want_read_modify_write(file, page, pos, len)) {
422 once_thru = 1;
423 ret = nfs_readpage(file, page);
424 page_cache_release(page);
425 if (!ret)
426 goto start;
427 }
428 return ret;
429}
430
431static int nfs_write_end(struct file *file, struct address_space *mapping,
432 loff_t pos, unsigned len, unsigned copied,
433 struct page *page, void *fsdata)
434{
435 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
436 int status;
437
438 dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n",
439 file->f_path.dentry->d_parent->d_name.name,
440 file->f_path.dentry->d_name.name,
441 mapping->host->i_ino, len, (long long) pos);
442
443 /*
444 * Zero any uninitialised parts of the page, and then mark the page
445 * as up to date if it turns out that we're extending the file.
446 */
447 if (!PageUptodate(page)) {
448 unsigned pglen = nfs_page_length(page);
449 unsigned end = offset + len;
450
451 if (pglen == 0) {
452 zero_user_segments(page, 0, offset,
453 end, PAGE_CACHE_SIZE);
454 SetPageUptodate(page);
455 } else if (end >= pglen) {
456 zero_user_segment(page, end, PAGE_CACHE_SIZE);
457 if (offset == 0)
458 SetPageUptodate(page);
459 } else
460 zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
461 }
462
463 status = nfs_updatepage(file, page, offset, copied);
464
465 unlock_page(page);
466 page_cache_release(page);
467
468 if (status < 0)
469 return status;
470 return copied;
471}
472
473/*
474 * Partially or wholly invalidate a page
475 * - Release the private state associated with a page if undergoing complete
476 * page invalidation
477 * - Called if either PG_private or PG_fscache is set on the page
478 * - Caller holds page lock
479 */
480static void nfs_invalidate_page(struct page *page, unsigned long offset)
481{
482 dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
483
484 if (offset != 0)
485 return;
486 /* Cancel any unstarted writes on this page */
487 nfs_wb_page_cancel(page->mapping->host, page);
488
489 nfs_fscache_invalidate_page(page, page->mapping->host);
490}
491
492/*
493 * Attempt to release the private state associated with a page
494 * - Called if either PG_private or PG_fscache is set on the page
495 * - Caller holds page lock
496 * - Return true (may release page) or false (may not)
497 */
498static int nfs_release_page(struct page *page, gfp_t gfp)
499{
500 struct address_space *mapping = page->mapping;
501
502 dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
503
504 /* Only do I/O if gfp is a superset of GFP_KERNEL */
505 if (mapping && (gfp & GFP_KERNEL) == GFP_KERNEL) {
506 int how = FLUSH_SYNC;
507
508 /* Don't let kswapd deadlock waiting for OOM RPC calls */
509 if (current_is_kswapd())
510 how = 0;
511 nfs_commit_inode(mapping->host, how);
512 }
513 /* If PagePrivate() is set, then the page is not freeable */
514 if (PagePrivate(page))
515 return 0;
516 return nfs_fscache_release_page(page, gfp);
517}
518
519/*
520 * Attempt to clear the private state associated with a page when an error
521 * occurs that requires the cached contents of an inode to be written back or
522 * destroyed
523 * - Called if either PG_private or fscache is set on the page
524 * - Caller holds page lock
525 * - Return 0 if successful, -error otherwise
526 */
527static int nfs_launder_page(struct page *page)
528{
529 struct inode *inode = page->mapping->host;
530 struct nfs_inode *nfsi = NFS_I(inode);
531
532 dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
533 inode->i_ino, (long long)page_offset(page));
534
535 nfs_fscache_wait_on_page_write(nfsi, page);
536 return nfs_wb_page(inode, page);
537}
538
539const struct address_space_operations nfs_file_aops = {
540 .readpage = nfs_readpage,
541 .readpages = nfs_readpages,
542 .set_page_dirty = __set_page_dirty_nobuffers,
543 .writepage = nfs_writepage,
544 .writepages = nfs_writepages,
545 .write_begin = nfs_write_begin,
546 .write_end = nfs_write_end,
547 .invalidatepage = nfs_invalidate_page,
548 .releasepage = nfs_release_page,
549 .direct_IO = nfs_direct_IO,
550 .migratepage = nfs_migrate_page,
551 .launder_page = nfs_launder_page,
552 .error_remove_page = generic_error_remove_page,
553};
554
555/*
556 * Notification that a PTE pointing to an NFS page is about to be made
557 * writable, implying that someone is about to modify the page through a
558 * shared-writable mapping
559 */
560static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
561{
562 struct page *page = vmf->page;
563 struct file *filp = vma->vm_file;
564 struct dentry *dentry = filp->f_path.dentry;
565 unsigned pagelen;
566 int ret = VM_FAULT_NOPAGE;
567 struct address_space *mapping;
568
569 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
570 dentry->d_parent->d_name.name, dentry->d_name.name,
571 filp->f_mapping->host->i_ino,
572 (long long)page_offset(page));
573
574 /* make sure the cache has finished storing the page */
575 nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
576
577 lock_page(page);
578 mapping = page->mapping;
579 if (mapping != dentry->d_inode->i_mapping)
580 goto out_unlock;
581
582 pagelen = nfs_page_length(page);
583 if (pagelen == 0)
584 goto out_unlock;
585
586 ret = VM_FAULT_LOCKED;
587 if (nfs_flush_incompatible(filp, page) == 0 &&
588 nfs_updatepage(filp, page, 0, pagelen) == 0)
589 goto out;
590
591 ret = VM_FAULT_SIGBUS;
592out_unlock:
593 unlock_page(page);
594out:
595 return ret;
596}
597
598static const struct vm_operations_struct nfs_file_vm_ops = {
599 .fault = filemap_fault,
600 .page_mkwrite = nfs_vm_page_mkwrite,
601};
602
603static int nfs_need_sync_write(struct file *filp, struct inode *inode)
604{
605 struct nfs_open_context *ctx;
606
607 if (IS_SYNC(inode) || (filp->f_flags & O_DSYNC))
608 return 1;
609 ctx = nfs_file_open_context(filp);
610 if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
611 return 1;
612 return 0;
613}
614
615static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
616 unsigned long nr_segs, loff_t pos)
617{
618 struct dentry * dentry = iocb->ki_filp->f_path.dentry;
619 struct inode * inode = dentry->d_inode;
620 unsigned long written = 0;
621 ssize_t result;
622 size_t count = iov_length(iov, nr_segs);
623
624 if (iocb->ki_filp->f_flags & O_DIRECT)
625 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
626
627 dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
628 dentry->d_parent->d_name.name, dentry->d_name.name,
629 (unsigned long) count, (long long) pos);
630
631 result = -EBUSY;
632 if (IS_SWAPFILE(inode))
633 goto out_swapfile;
634 /*
635 * O_APPEND implies that we must revalidate the file length.
636 */
637 if (iocb->ki_filp->f_flags & O_APPEND) {
638 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
639 if (result)
640 goto out;
641 }
642
643 result = count;
644 if (!count)
645 goto out;
646
647 result = generic_file_aio_write(iocb, iov, nr_segs, pos);
648 if (result > 0)
649 written = result;
650
651 /* Return error values for O_DSYNC and IS_SYNC() */
652 if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
653 int err = vfs_fsync(iocb->ki_filp, 0);
654 if (err < 0)
655 result = err;
656 }
657 if (result > 0)
658 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
659out:
660 return result;
661
662out_swapfile:
663 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
664 goto out;
665}
666
667static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
668 struct file *filp, loff_t *ppos,
669 size_t count, unsigned int flags)
670{
671 struct dentry *dentry = filp->f_path.dentry;
672 struct inode *inode = dentry->d_inode;
673 unsigned long written = 0;
674 ssize_t ret;
675
676 dprintk("NFS splice_write(%s/%s, %lu@%llu)\n",
677 dentry->d_parent->d_name.name, dentry->d_name.name,
678 (unsigned long) count, (unsigned long long) *ppos);
679
680 /*
681 * The combination of splice and an O_APPEND destination is disallowed.
682 */
683
684 ret = generic_file_splice_write(pipe, filp, ppos, count, flags);
685 if (ret > 0)
686 written = ret;
687
688 if (ret >= 0 && nfs_need_sync_write(filp, inode)) {
689 int err = vfs_fsync(filp, 0);
690 if (err < 0)
691 ret = err;
692 }
693 if (ret > 0)
694 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
695 return ret;
696}
697
698static int
699do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
700{
701 struct inode *inode = filp->f_mapping->host;
702 int status = 0;
703 unsigned int saved_type = fl->fl_type;
704
705 /* Try local locking first */
706 posix_test_lock(filp, fl);
707 if (fl->fl_type != F_UNLCK) {
708 /* found a conflict */
709 goto out;
710 }
711 fl->fl_type = saved_type;
712
713 if (nfs_have_delegation(inode, FMODE_READ))
714 goto out_noconflict;
715
716 if (is_local)
717 goto out_noconflict;
718
719 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
720out:
721 return status;
722out_noconflict:
723 fl->fl_type = F_UNLCK;
724 goto out;
725}
726
727static int do_vfs_lock(struct file *file, struct file_lock *fl)
728{
729 int res = 0;
730 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
731 case FL_POSIX:
732 res = posix_lock_file_wait(file, fl);
733 break;
734 case FL_FLOCK:
735 res = flock_lock_file_wait(file, fl);
736 break;
737 default:
738 BUG();
739 }
740 return res;
741}
742
743static int
744do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
745{
746 struct inode *inode = filp->f_mapping->host;
747 int status;
748
749 /*
750 * Flush all pending writes before doing anything
751 * with locks..
752 */
753 nfs_sync_mapping(filp->f_mapping);
754
755 /* NOTE: special case
756 * If we're signalled while cleaning up locks on process exit, we
757 * still need to complete the unlock.
758 */
759 /*
760 * Use local locking if mounted with "-onolock" or with appropriate
761 * "-olocal_lock="
762 */
763 if (!is_local)
764 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
765 else
766 status = do_vfs_lock(filp, fl);
767 return status;
768}
769
770static int
771is_time_granular(struct timespec *ts) {
772 return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000));
773}
774
775static int
776do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
777{
778 struct inode *inode = filp->f_mapping->host;
779 int status;
780
781 /*
782 * Flush all pending writes before doing anything
783 * with locks..
784 */
785 status = nfs_sync_mapping(filp->f_mapping);
786 if (status != 0)
787 goto out;
788
789 /*
790 * Use local locking if mounted with "-onolock" or with appropriate
791 * "-olocal_lock="
792 */
793 if (!is_local)
794 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
795 else
796 status = do_vfs_lock(filp, fl);
797 if (status < 0)
798 goto out;
799
800 /*
801 * Revalidate the cache if the server has time stamps granular
802 * enough to detect subsecond changes. Otherwise, clear the
803 * cache to prevent missing any changes.
804 *
805 * This makes locking act as a cache coherency point.
806 */
807 nfs_sync_mapping(filp->f_mapping);
808 if (!nfs_have_delegation(inode, FMODE_READ)) {
809 if (is_time_granular(&NFS_SERVER(inode)->time_delta))
810 __nfs_revalidate_inode(NFS_SERVER(inode), inode);
811 else
812 nfs_zap_caches(inode);
813 }
814out:
815 return status;
816}
817
818/*
819 * Lock a (portion of) a file
820 */
821static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
822{
823 struct inode *inode = filp->f_mapping->host;
824 int ret = -ENOLCK;
825 int is_local = 0;
826
827 dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n",
828 filp->f_path.dentry->d_parent->d_name.name,
829 filp->f_path.dentry->d_name.name,
830 fl->fl_type, fl->fl_flags,
831 (long long)fl->fl_start, (long long)fl->fl_end);
832
833 nfs_inc_stats(inode, NFSIOS_VFSLOCK);
834
835 /* No mandatory locks over NFS */
836 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
837 goto out_err;
838
839 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
840 is_local = 1;
841
842 if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
843 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
844 if (ret < 0)
845 goto out_err;
846 }
847
848 if (IS_GETLK(cmd))
849 ret = do_getlk(filp, cmd, fl, is_local);
850 else if (fl->fl_type == F_UNLCK)
851 ret = do_unlk(filp, cmd, fl, is_local);
852 else
853 ret = do_setlk(filp, cmd, fl, is_local);
854out_err:
855 return ret;
856}
857
858/*
859 * Lock a (portion of) a file
860 */
861static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
862{
863 struct inode *inode = filp->f_mapping->host;
864 int is_local = 0;
865
866 dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n",
867 filp->f_path.dentry->d_parent->d_name.name,
868 filp->f_path.dentry->d_name.name,
869 fl->fl_type, fl->fl_flags);
870
871 if (!(fl->fl_flags & FL_FLOCK))
872 return -ENOLCK;
873
874 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
875 is_local = 1;
876
877 /* We're simulating flock() locks using posix locks on the server */
878 fl->fl_owner = (fl_owner_t)filp;
879 fl->fl_start = 0;
880 fl->fl_end = OFFSET_MAX;
881
882 if (fl->fl_type == F_UNLCK)
883 return do_unlk(filp, cmd, fl, is_local);
884 return do_setlk(filp, cmd, fl, is_local);
885}
886
887/*
888 * There is no protocol support for leases, so we have no way to implement
889 * them correctly in the face of opens by other clients.
890 */
891static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
892{
893 dprintk("NFS: setlease(%s/%s, arg=%ld)\n",
894 file->f_path.dentry->d_parent->d_name.name,
895 file->f_path.dentry->d_name.name, arg);
896 return -EINVAL;
897}
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);