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
42 static const struct vm_operations_struct nfs_file_vm_ops;
43
44 const 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
51 const 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
nfs_check_flags(int flags)67 static 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 */
78 static int
nfs_file_open(struct inode * inode,struct file * filp)79 nfs_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
96 static int
nfs_file_release(struct inode * inode,struct file * filp)97 nfs_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 */
nfs_revalidate_file_size(struct inode * inode,struct file * filp)118 static 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;
132 out_noreval:
133 return 0;
134 force_reval:
135 return __nfs_revalidate_inode(server, inode);
136 }
137
nfs_file_llseek(struct file * filp,loff_t offset,int origin)138 static 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 */
163 static int
nfs_file_flush(struct file * file,fl_owner_t id)164 nfs_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 /* Flush writes to the server and return any errors */
178 return vfs_fsync(file, 0);
179 }
180
181 static ssize_t
nfs_file_read(struct kiocb * iocb,const struct iovec * iov,unsigned long nr_segs,loff_t pos)182 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
183 unsigned long nr_segs, loff_t pos)
184 {
185 struct dentry * dentry = iocb->ki_filp->f_path.dentry;
186 struct inode * inode = dentry->d_inode;
187 ssize_t result;
188
189 if (iocb->ki_filp->f_flags & O_DIRECT)
190 return nfs_file_direct_read(iocb, iov, nr_segs, pos);
191
192 dprintk("NFS: read(%s/%s, %lu@%lu)\n",
193 dentry->d_parent->d_name.name, dentry->d_name.name,
194 (unsigned long) iov_length(iov, nr_segs), (unsigned long) pos);
195
196 result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
197 if (!result) {
198 result = generic_file_aio_read(iocb, iov, nr_segs, pos);
199 if (result > 0)
200 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
201 }
202 return result;
203 }
204
205 static ssize_t
nfs_file_splice_read(struct file * filp,loff_t * ppos,struct pipe_inode_info * pipe,size_t count,unsigned int flags)206 nfs_file_splice_read(struct file *filp, loff_t *ppos,
207 struct pipe_inode_info *pipe, size_t count,
208 unsigned int flags)
209 {
210 struct dentry *dentry = filp->f_path.dentry;
211 struct inode *inode = dentry->d_inode;
212 ssize_t res;
213
214 dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n",
215 dentry->d_parent->d_name.name, dentry->d_name.name,
216 (unsigned long) count, (unsigned long long) *ppos);
217
218 res = nfs_revalidate_mapping(inode, filp->f_mapping);
219 if (!res) {
220 res = generic_file_splice_read(filp, ppos, pipe, count, flags);
221 if (res > 0)
222 nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, res);
223 }
224 return res;
225 }
226
227 static int
nfs_file_mmap(struct file * file,struct vm_area_struct * vma)228 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
229 {
230 struct dentry *dentry = file->f_path.dentry;
231 struct inode *inode = dentry->d_inode;
232 int status;
233
234 dprintk("NFS: mmap(%s/%s)\n",
235 dentry->d_parent->d_name.name, dentry->d_name.name);
236
237 /* Note: generic_file_mmap() returns ENOSYS on nommu systems
238 * so we call that before revalidating the mapping
239 */
240 status = generic_file_mmap(file, vma);
241 if (!status) {
242 vma->vm_ops = &nfs_file_vm_ops;
243 status = nfs_revalidate_mapping(inode, file->f_mapping);
244 }
245 return status;
246 }
247
248 /*
249 * Flush any dirty pages for this process, and check for write errors.
250 * The return status from this call provides a reliable indication of
251 * whether any write errors occurred for this process.
252 *
253 * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
254 * disk, but it retrieves and clears ctx->error after synching, despite
255 * the two being set at the same time in nfs_context_set_write_error().
256 * This is because the former is used to notify the _next_ call to
257 * nfs_file_write() that a write error occurred, and hence cause it to
258 * fall back to doing a synchronous write.
259 */
260 static int
nfs_file_fsync(struct file * file,loff_t start,loff_t end,int datasync)261 nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
262 {
263 struct dentry *dentry = file->f_path.dentry;
264 struct nfs_open_context *ctx = nfs_file_open_context(file);
265 struct inode *inode = dentry->d_inode;
266 int have_error, status;
267 int ret = 0;
268
269 dprintk("NFS: fsync file(%s/%s) datasync %d\n",
270 dentry->d_parent->d_name.name, dentry->d_name.name,
271 datasync);
272
273 ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
274 mutex_lock(&inode->i_mutex);
275
276 nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
277 have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
278 status = nfs_commit_inode(inode, FLUSH_SYNC);
279 if (status >= 0 && ret < 0)
280 status = ret;
281 have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
282 if (have_error)
283 ret = xchg(&ctx->error, 0);
284 if (!ret && status < 0)
285 ret = status;
286 if (!ret && !datasync)
287 /* application has asked for meta-data sync */
288 ret = pnfs_layoutcommit_inode(inode, true);
289 mutex_unlock(&inode->i_mutex);
290 return ret;
291 }
292
293 /*
294 * Decide whether a read/modify/write cycle may be more efficient
295 * then a modify/write/read cycle when writing to a page in the
296 * page cache.
297 *
298 * The modify/write/read cycle may occur if a page is read before
299 * being completely filled by the writer. In this situation, the
300 * page must be completely written to stable storage on the server
301 * before it can be refilled by reading in the page from the server.
302 * This can lead to expensive, small, FILE_SYNC mode writes being
303 * done.
304 *
305 * It may be more efficient to read the page first if the file is
306 * open for reading in addition to writing, the page is not marked
307 * as Uptodate, it is not dirty or waiting to be committed,
308 * indicating that it was previously allocated and then modified,
309 * that there were valid bytes of data in that range of the file,
310 * and that the new data won't completely replace the old data in
311 * that range of the file.
312 */
nfs_want_read_modify_write(struct file * file,struct page * page,loff_t pos,unsigned len)313 static int nfs_want_read_modify_write(struct file *file, struct page *page,
314 loff_t pos, unsigned len)
315 {
316 unsigned int pglen = nfs_page_length(page);
317 unsigned int offset = pos & (PAGE_CACHE_SIZE - 1);
318 unsigned int end = offset + len;
319
320 if ((file->f_mode & FMODE_READ) && /* open for read? */
321 !PageUptodate(page) && /* Uptodate? */
322 !PagePrivate(page) && /* i/o request already? */
323 pglen && /* valid bytes of file? */
324 (end < pglen || offset)) /* replace all valid bytes? */
325 return 1;
326 return 0;
327 }
328
329 /*
330 * This does the "real" work of the write. We must allocate and lock the
331 * page to be sent back to the generic routine, which then copies the
332 * data from user space.
333 *
334 * If the writer ends up delaying the write, the writer needs to
335 * increment the page use counts until he is done with the page.
336 */
nfs_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned flags,struct page ** pagep,void ** fsdata)337 static int nfs_write_begin(struct file *file, struct address_space *mapping,
338 loff_t pos, unsigned len, unsigned flags,
339 struct page **pagep, void **fsdata)
340 {
341 int ret;
342 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
343 struct page *page;
344 int once_thru = 0;
345
346 dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n",
347 file->f_path.dentry->d_parent->d_name.name,
348 file->f_path.dentry->d_name.name,
349 mapping->host->i_ino, len, (long long) pos);
350
351 start:
352 /*
353 * Prevent starvation issues if someone is doing a consistency
354 * sync-to-disk
355 */
356 ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
357 nfs_wait_bit_killable, TASK_KILLABLE);
358 if (ret)
359 return ret;
360
361 page = grab_cache_page_write_begin(mapping, index, flags);
362 if (!page)
363 return -ENOMEM;
364 *pagep = page;
365
366 ret = nfs_flush_incompatible(file, page);
367 if (ret) {
368 unlock_page(page);
369 page_cache_release(page);
370 } else if (!once_thru &&
371 nfs_want_read_modify_write(file, page, pos, len)) {
372 once_thru = 1;
373 ret = nfs_readpage(file, page);
374 page_cache_release(page);
375 if (!ret)
376 goto start;
377 }
378 return ret;
379 }
380
nfs_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)381 static int nfs_write_end(struct file *file, struct address_space *mapping,
382 loff_t pos, unsigned len, unsigned copied,
383 struct page *page, void *fsdata)
384 {
385 unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
386 int status;
387
388 dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n",
389 file->f_path.dentry->d_parent->d_name.name,
390 file->f_path.dentry->d_name.name,
391 mapping->host->i_ino, len, (long long) pos);
392
393 /*
394 * Zero any uninitialised parts of the page, and then mark the page
395 * as up to date if it turns out that we're extending the file.
396 */
397 if (!PageUptodate(page)) {
398 unsigned pglen = nfs_page_length(page);
399 unsigned end = offset + len;
400
401 if (pglen == 0) {
402 zero_user_segments(page, 0, offset,
403 end, PAGE_CACHE_SIZE);
404 SetPageUptodate(page);
405 } else if (end >= pglen) {
406 zero_user_segment(page, end, PAGE_CACHE_SIZE);
407 if (offset == 0)
408 SetPageUptodate(page);
409 } else
410 zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
411 }
412
413 status = nfs_updatepage(file, page, offset, copied);
414
415 unlock_page(page);
416 page_cache_release(page);
417
418 if (status < 0)
419 return status;
420 return copied;
421 }
422
423 /*
424 * Partially or wholly invalidate a page
425 * - Release the private state associated with a page if undergoing complete
426 * page invalidation
427 * - Called if either PG_private or PG_fscache is set on the page
428 * - Caller holds page lock
429 */
nfs_invalidate_page(struct page * page,unsigned long offset)430 static void nfs_invalidate_page(struct page *page, unsigned long offset)
431 {
432 dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
433
434 if (offset != 0)
435 return;
436 /* Cancel any unstarted writes on this page */
437 nfs_wb_page_cancel(page->mapping->host, page);
438
439 nfs_fscache_invalidate_page(page, page->mapping->host);
440 }
441
442 /*
443 * Attempt to release the private state associated with a page
444 * - Called if either PG_private or PG_fscache is set on the page
445 * - Caller holds page lock
446 * - Return true (may release page) or false (may not)
447 */
nfs_release_page(struct page * page,gfp_t gfp)448 static int nfs_release_page(struct page *page, gfp_t gfp)
449 {
450 struct address_space *mapping = page->mapping;
451
452 dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
453
454 /* Only do I/O if gfp is a superset of GFP_KERNEL, and we're not
455 * doing this memory reclaim for a fs-related allocation.
456 */
457 if (mapping && (gfp & GFP_KERNEL) == GFP_KERNEL &&
458 !(current->flags & PF_FSTRANS)) {
459 int how = FLUSH_SYNC;
460
461 /* Don't let kswapd deadlock waiting for OOM RPC calls */
462 if (current_is_kswapd())
463 how = 0;
464 nfs_commit_inode(mapping->host, how);
465 }
466 /* If PagePrivate() is set, then the page is not freeable */
467 if (PagePrivate(page))
468 return 0;
469 return nfs_fscache_release_page(page, gfp);
470 }
471
472 /*
473 * Attempt to clear the private state associated with a page when an error
474 * occurs that requires the cached contents of an inode to be written back or
475 * destroyed
476 * - Called if either PG_private or fscache is set on the page
477 * - Caller holds page lock
478 * - Return 0 if successful, -error otherwise
479 */
nfs_launder_page(struct page * page)480 static int nfs_launder_page(struct page *page)
481 {
482 struct inode *inode = page->mapping->host;
483 struct nfs_inode *nfsi = NFS_I(inode);
484
485 dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
486 inode->i_ino, (long long)page_offset(page));
487
488 nfs_fscache_wait_on_page_write(nfsi, page);
489 return nfs_wb_page(inode, page);
490 }
491
492 const struct address_space_operations nfs_file_aops = {
493 .readpage = nfs_readpage,
494 .readpages = nfs_readpages,
495 .set_page_dirty = __set_page_dirty_nobuffers,
496 .writepage = nfs_writepage,
497 .writepages = nfs_writepages,
498 .write_begin = nfs_write_begin,
499 .write_end = nfs_write_end,
500 .invalidatepage = nfs_invalidate_page,
501 .releasepage = nfs_release_page,
502 .direct_IO = nfs_direct_IO,
503 .migratepage = nfs_migrate_page,
504 .launder_page = nfs_launder_page,
505 .error_remove_page = generic_error_remove_page,
506 };
507
508 /*
509 * Notification that a PTE pointing to an NFS page is about to be made
510 * writable, implying that someone is about to modify the page through a
511 * shared-writable mapping
512 */
nfs_vm_page_mkwrite(struct vm_area_struct * vma,struct vm_fault * vmf)513 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
514 {
515 struct page *page = vmf->page;
516 struct file *filp = vma->vm_file;
517 struct dentry *dentry = filp->f_path.dentry;
518 unsigned pagelen;
519 int ret = VM_FAULT_NOPAGE;
520 struct address_space *mapping;
521
522 dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
523 dentry->d_parent->d_name.name, dentry->d_name.name,
524 filp->f_mapping->host->i_ino,
525 (long long)page_offset(page));
526
527 /* make sure the cache has finished storing the page */
528 nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
529
530 lock_page(page);
531 mapping = page->mapping;
532 if (mapping != dentry->d_inode->i_mapping)
533 goto out_unlock;
534
535 wait_on_page_writeback(page);
536
537 pagelen = nfs_page_length(page);
538 if (pagelen == 0)
539 goto out_unlock;
540
541 ret = VM_FAULT_LOCKED;
542 if (nfs_flush_incompatible(filp, page) == 0 &&
543 nfs_updatepage(filp, page, 0, pagelen) == 0)
544 goto out;
545
546 ret = VM_FAULT_SIGBUS;
547 out_unlock:
548 unlock_page(page);
549 out:
550 return ret;
551 }
552
553 static const struct vm_operations_struct nfs_file_vm_ops = {
554 .fault = filemap_fault,
555 .page_mkwrite = nfs_vm_page_mkwrite,
556 };
557
nfs_need_sync_write(struct file * filp,struct inode * inode)558 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
559 {
560 struct nfs_open_context *ctx;
561
562 if (IS_SYNC(inode) || (filp->f_flags & O_DSYNC))
563 return 1;
564 ctx = nfs_file_open_context(filp);
565 if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
566 return 1;
567 return 0;
568 }
569
nfs_file_write(struct kiocb * iocb,const struct iovec * iov,unsigned long nr_segs,loff_t pos)570 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
571 unsigned long nr_segs, loff_t pos)
572 {
573 struct dentry * dentry = iocb->ki_filp->f_path.dentry;
574 struct inode * inode = dentry->d_inode;
575 unsigned long written = 0;
576 ssize_t result;
577 size_t count = iov_length(iov, nr_segs);
578
579 if (iocb->ki_filp->f_flags & O_DIRECT)
580 return nfs_file_direct_write(iocb, iov, nr_segs, pos);
581
582 dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
583 dentry->d_parent->d_name.name, dentry->d_name.name,
584 (unsigned long) count, (long long) pos);
585
586 result = -EBUSY;
587 if (IS_SWAPFILE(inode))
588 goto out_swapfile;
589 /*
590 * O_APPEND implies that we must revalidate the file length.
591 */
592 if (iocb->ki_filp->f_flags & O_APPEND) {
593 result = nfs_revalidate_file_size(inode, iocb->ki_filp);
594 if (result)
595 goto out;
596 }
597
598 result = count;
599 if (!count)
600 goto out;
601
602 result = generic_file_aio_write(iocb, iov, nr_segs, pos);
603 if (result > 0)
604 written = result;
605
606 /* Return error values for O_DSYNC and IS_SYNC() */
607 if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
608 int err = vfs_fsync(iocb->ki_filp, 0);
609 if (err < 0)
610 result = err;
611 }
612 if (result > 0)
613 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
614 out:
615 return result;
616
617 out_swapfile:
618 printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
619 goto out;
620 }
621
nfs_file_splice_write(struct pipe_inode_info * pipe,struct file * filp,loff_t * ppos,size_t count,unsigned int flags)622 static ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe,
623 struct file *filp, loff_t *ppos,
624 size_t count, unsigned int flags)
625 {
626 struct dentry *dentry = filp->f_path.dentry;
627 struct inode *inode = dentry->d_inode;
628 unsigned long written = 0;
629 ssize_t ret;
630
631 dprintk("NFS splice_write(%s/%s, %lu@%llu)\n",
632 dentry->d_parent->d_name.name, dentry->d_name.name,
633 (unsigned long) count, (unsigned long long) *ppos);
634
635 /*
636 * The combination of splice and an O_APPEND destination is disallowed.
637 */
638
639 ret = generic_file_splice_write(pipe, filp, ppos, count, flags);
640 if (ret > 0)
641 written = ret;
642
643 if (ret >= 0 && nfs_need_sync_write(filp, inode)) {
644 int err = vfs_fsync(filp, 0);
645 if (err < 0)
646 ret = err;
647 }
648 if (ret > 0)
649 nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
650 return ret;
651 }
652
653 static int
do_getlk(struct file * filp,int cmd,struct file_lock * fl,int is_local)654 do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
655 {
656 struct inode *inode = filp->f_mapping->host;
657 int status = 0;
658 unsigned int saved_type = fl->fl_type;
659
660 /* Try local locking first */
661 posix_test_lock(filp, fl);
662 if (fl->fl_type != F_UNLCK) {
663 /* found a conflict */
664 goto out;
665 }
666 fl->fl_type = saved_type;
667
668 if (nfs_have_delegation(inode, FMODE_READ))
669 goto out_noconflict;
670
671 if (is_local)
672 goto out_noconflict;
673
674 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
675 out:
676 return status;
677 out_noconflict:
678 fl->fl_type = F_UNLCK;
679 goto out;
680 }
681
do_vfs_lock(struct file * file,struct file_lock * fl)682 static int do_vfs_lock(struct file *file, struct file_lock *fl)
683 {
684 int res = 0;
685 switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
686 case FL_POSIX:
687 res = posix_lock_file_wait(file, fl);
688 break;
689 case FL_FLOCK:
690 res = flock_lock_file_wait(file, fl);
691 break;
692 default:
693 BUG();
694 }
695 return res;
696 }
697
698 static int
do_unlk(struct file * filp,int cmd,struct file_lock * fl,int is_local)699 do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
700 {
701 struct inode *inode = filp->f_mapping->host;
702 int status;
703
704 /*
705 * Flush all pending writes before doing anything
706 * with locks..
707 */
708 nfs_sync_mapping(filp->f_mapping);
709
710 /* NOTE: special case
711 * If we're signalled while cleaning up locks on process exit, we
712 * still need to complete the unlock.
713 */
714 /*
715 * Use local locking if mounted with "-onolock" or with appropriate
716 * "-olocal_lock="
717 */
718 if (!is_local)
719 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
720 else
721 status = do_vfs_lock(filp, fl);
722 return status;
723 }
724
725 static int
is_time_granular(struct timespec * ts)726 is_time_granular(struct timespec *ts) {
727 return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000));
728 }
729
730 static int
do_setlk(struct file * filp,int cmd,struct file_lock * fl,int is_local)731 do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
732 {
733 struct inode *inode = filp->f_mapping->host;
734 int status;
735
736 /*
737 * Flush all pending writes before doing anything
738 * with locks..
739 */
740 status = nfs_sync_mapping(filp->f_mapping);
741 if (status != 0)
742 goto out;
743
744 /*
745 * Use local locking if mounted with "-onolock" or with appropriate
746 * "-olocal_lock="
747 */
748 if (!is_local)
749 status = NFS_PROTO(inode)->lock(filp, cmd, fl);
750 else
751 status = do_vfs_lock(filp, fl);
752 if (status < 0)
753 goto out;
754
755 /*
756 * Revalidate the cache if the server has time stamps granular
757 * enough to detect subsecond changes. Otherwise, clear the
758 * cache to prevent missing any changes.
759 *
760 * This makes locking act as a cache coherency point.
761 */
762 nfs_sync_mapping(filp->f_mapping);
763 if (!nfs_have_delegation(inode, FMODE_READ)) {
764 if (is_time_granular(&NFS_SERVER(inode)->time_delta))
765 __nfs_revalidate_inode(NFS_SERVER(inode), inode);
766 else
767 nfs_zap_caches(inode);
768 }
769 out:
770 return status;
771 }
772
773 /*
774 * Lock a (portion of) a file
775 */
nfs_lock(struct file * filp,int cmd,struct file_lock * fl)776 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
777 {
778 struct inode *inode = filp->f_mapping->host;
779 int ret = -ENOLCK;
780 int is_local = 0;
781
782 dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n",
783 filp->f_path.dentry->d_parent->d_name.name,
784 filp->f_path.dentry->d_name.name,
785 fl->fl_type, fl->fl_flags,
786 (long long)fl->fl_start, (long long)fl->fl_end);
787
788 nfs_inc_stats(inode, NFSIOS_VFSLOCK);
789
790 /* No mandatory locks over NFS */
791 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
792 goto out_err;
793
794 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
795 is_local = 1;
796
797 if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
798 ret = NFS_PROTO(inode)->lock_check_bounds(fl);
799 if (ret < 0)
800 goto out_err;
801 }
802
803 if (IS_GETLK(cmd))
804 ret = do_getlk(filp, cmd, fl, is_local);
805 else if (fl->fl_type == F_UNLCK)
806 ret = do_unlk(filp, cmd, fl, is_local);
807 else
808 ret = do_setlk(filp, cmd, fl, is_local);
809 out_err:
810 return ret;
811 }
812
813 /*
814 * Lock a (portion of) a file
815 */
nfs_flock(struct file * filp,int cmd,struct file_lock * fl)816 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
817 {
818 struct inode *inode = filp->f_mapping->host;
819 int is_local = 0;
820
821 dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n",
822 filp->f_path.dentry->d_parent->d_name.name,
823 filp->f_path.dentry->d_name.name,
824 fl->fl_type, fl->fl_flags);
825
826 if (!(fl->fl_flags & FL_FLOCK))
827 return -ENOLCK;
828
829 if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
830 is_local = 1;
831
832 /* We're simulating flock() locks using posix locks on the server */
833 fl->fl_owner = (fl_owner_t)filp;
834 fl->fl_start = 0;
835 fl->fl_end = OFFSET_MAX;
836
837 if (fl->fl_type == F_UNLCK)
838 return do_unlk(filp, cmd, fl, is_local);
839 return do_setlk(filp, cmd, fl, is_local);
840 }
841
842 /*
843 * There is no protocol support for leases, so we have no way to implement
844 * them correctly in the face of opens by other clients.
845 */
nfs_setlease(struct file * file,long arg,struct file_lock ** fl)846 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
847 {
848 dprintk("NFS: setlease(%s/%s, arg=%ld)\n",
849 file->f_path.dentry->d_parent->d_name.name,
850 file->f_path.dentry->d_name.name, arg);
851 return -EINVAL;
852 }
853
854 const struct file_operations nfs_file_operations = {
855 .llseek = nfs_file_llseek,
856 .read = do_sync_read,
857 .write = do_sync_write,
858 .aio_read = nfs_file_read,
859 .aio_write = nfs_file_write,
860 .mmap = nfs_file_mmap,
861 .open = nfs_file_open,
862 .flush = nfs_file_flush,
863 .release = nfs_file_release,
864 .fsync = nfs_file_fsync,
865 .lock = nfs_lock,
866 .flock = nfs_flock,
867 .splice_read = nfs_file_splice_read,
868 .splice_write = nfs_file_splice_write,
869 .check_flags = nfs_check_flags,
870 .setlease = nfs_setlease,
871 };
872
873 #ifdef CONFIG_NFS_V4
874 static int
nfs4_file_open(struct inode * inode,struct file * filp)875 nfs4_file_open(struct inode *inode, struct file *filp)
876 {
877 /*
878 * NFSv4 opens are handled in d_lookup and d_revalidate. If we get to
879 * this point, then something is very wrong
880 */
881 dprintk("NFS: %s called! inode=%p filp=%p\n", __func__, inode, filp);
882 return -ENOTDIR;
883 }
884
885 const struct file_operations nfs4_file_operations = {
886 .llseek = nfs_file_llseek,
887 .read = do_sync_read,
888 .write = do_sync_write,
889 .aio_read = nfs_file_read,
890 .aio_write = nfs_file_write,
891 .mmap = nfs_file_mmap,
892 .open = nfs4_file_open,
893 .flush = nfs_file_flush,
894 .release = nfs_file_release,
895 .fsync = nfs_file_fsync,
896 .lock = nfs_lock,
897 .flock = nfs_flock,
898 .splice_read = nfs_file_splice_read,
899 .splice_write = nfs_file_splice_write,
900 .check_flags = nfs_check_flags,
901 .setlease = nfs_setlease,
902 };
903 #endif /* CONFIG_NFS_V4 */
904