xref: /openbmc/linux/fs/nfs/file.c (revision b04b4f78)
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/slab.h>
28 #include <linux/pagemap.h>
29 #include <linux/smp_lock.h>
30 #include <linux/aio.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 
40 #define NFSDBG_FACILITY		NFSDBG_FILE
41 
42 static int nfs_file_open(struct inode *, struct file *);
43 static int nfs_file_release(struct inode *, struct file *);
44 static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
45 static int  nfs_file_mmap(struct file *, struct vm_area_struct *);
46 static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
47 					struct pipe_inode_info *pipe,
48 					size_t count, unsigned int flags);
49 static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
50 				unsigned long nr_segs, loff_t pos);
51 static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
52 				unsigned long nr_segs, loff_t pos);
53 static int  nfs_file_flush(struct file *, fl_owner_t id);
54 static int  nfs_file_fsync(struct file *, struct dentry *dentry, int datasync);
55 static int nfs_check_flags(int flags);
56 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
57 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
58 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
59 
60 static struct vm_operations_struct nfs_file_vm_ops;
61 
62 const struct file_operations nfs_file_operations = {
63 	.llseek		= nfs_file_llseek,
64 	.read		= do_sync_read,
65 	.write		= do_sync_write,
66 	.aio_read	= nfs_file_read,
67 	.aio_write	= nfs_file_write,
68 	.mmap		= nfs_file_mmap,
69 	.open		= nfs_file_open,
70 	.flush		= nfs_file_flush,
71 	.release	= nfs_file_release,
72 	.fsync		= nfs_file_fsync,
73 	.lock		= nfs_lock,
74 	.flock		= nfs_flock,
75 	.splice_read	= nfs_file_splice_read,
76 	.check_flags	= nfs_check_flags,
77 	.setlease	= nfs_setlease,
78 };
79 
80 const struct inode_operations nfs_file_inode_operations = {
81 	.permission	= nfs_permission,
82 	.getattr	= nfs_getattr,
83 	.setattr	= nfs_setattr,
84 };
85 
86 #ifdef CONFIG_NFS_V3
87 const struct inode_operations nfs3_file_inode_operations = {
88 	.permission	= nfs_permission,
89 	.getattr	= nfs_getattr,
90 	.setattr	= nfs_setattr,
91 	.listxattr	= nfs3_listxattr,
92 	.getxattr	= nfs3_getxattr,
93 	.setxattr	= nfs3_setxattr,
94 	.removexattr	= nfs3_removexattr,
95 };
96 #endif  /* CONFIG_NFS_v3 */
97 
98 /* Hack for future NFS swap support */
99 #ifndef IS_SWAPFILE
100 # define IS_SWAPFILE(inode)	(0)
101 #endif
102 
103 static int nfs_check_flags(int flags)
104 {
105 	if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
106 		return -EINVAL;
107 
108 	return 0;
109 }
110 
111 /*
112  * Open file
113  */
114 static int
115 nfs_file_open(struct inode *inode, struct file *filp)
116 {
117 	int res;
118 
119 	dprintk("NFS: open file(%s/%s)\n",
120 			filp->f_path.dentry->d_parent->d_name.name,
121 			filp->f_path.dentry->d_name.name);
122 
123 	res = nfs_check_flags(filp->f_flags);
124 	if (res)
125 		return res;
126 
127 	nfs_inc_stats(inode, NFSIOS_VFSOPEN);
128 	res = nfs_open(inode, filp);
129 	return res;
130 }
131 
132 static int
133 nfs_file_release(struct inode *inode, struct file *filp)
134 {
135 	struct dentry *dentry = filp->f_path.dentry;
136 
137 	dprintk("NFS: release(%s/%s)\n",
138 			dentry->d_parent->d_name.name,
139 			dentry->d_name.name);
140 
141 	nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
142 	return nfs_release(inode, filp);
143 }
144 
145 /**
146  * nfs_revalidate_size - Revalidate the file size
147  * @inode - pointer to inode struct
148  * @file - pointer to struct file
149  *
150  * Revalidates the file length. This is basically a wrapper around
151  * nfs_revalidate_inode() that takes into account the fact that we may
152  * have cached writes (in which case we don't care about the server's
153  * idea of what the file length is), or O_DIRECT (in which case we
154  * shouldn't trust the cache).
155  */
156 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
157 {
158 	struct nfs_server *server = NFS_SERVER(inode);
159 	struct nfs_inode *nfsi = NFS_I(inode);
160 
161 	if (server->flags & NFS_MOUNT_NOAC)
162 		goto force_reval;
163 	if (filp->f_flags & O_DIRECT)
164 		goto force_reval;
165 	if (nfsi->npages != 0)
166 		return 0;
167 	if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
168 		return 0;
169 force_reval:
170 	return __nfs_revalidate_inode(server, inode);
171 }
172 
173 static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
174 {
175 	loff_t loff;
176 
177 	dprintk("NFS: llseek file(%s/%s, %lld, %d)\n",
178 			filp->f_path.dentry->d_parent->d_name.name,
179 			filp->f_path.dentry->d_name.name,
180 			offset, origin);
181 
182 	/* origin == SEEK_END => we must revalidate the cached file length */
183 	if (origin == SEEK_END) {
184 		struct inode *inode = filp->f_mapping->host;
185 
186 		int retval = nfs_revalidate_file_size(inode, filp);
187 		if (retval < 0)
188 			return (loff_t)retval;
189 
190 		spin_lock(&inode->i_lock);
191 		loff = generic_file_llseek_unlocked(filp, offset, origin);
192 		spin_unlock(&inode->i_lock);
193 	} else
194 		loff = generic_file_llseek_unlocked(filp, offset, origin);
195 	return loff;
196 }
197 
198 /*
199  * Helper for nfs_file_flush() and nfs_file_fsync()
200  *
201  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
202  * disk, but it retrieves and clears ctx->error after synching, despite
203  * the two being set at the same time in nfs_context_set_write_error().
204  * This is because the former is used to notify the _next_ call to
205  * nfs_file_write() that a write error occured, and hence cause it to
206  * fall back to doing a synchronous write.
207  */
208 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
209 {
210 	int have_error, status;
211 	int ret = 0;
212 
213 	have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
214 	status = nfs_wb_all(inode);
215 	have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
216 	if (have_error)
217 		ret = xchg(&ctx->error, 0);
218 	if (!ret)
219 		ret = status;
220 	return ret;
221 }
222 
223 /*
224  * Flush all dirty pages, and check for write errors.
225  */
226 static int
227 nfs_file_flush(struct file *file, fl_owner_t id)
228 {
229 	struct nfs_open_context *ctx = nfs_file_open_context(file);
230 	struct dentry	*dentry = file->f_path.dentry;
231 	struct inode	*inode = dentry->d_inode;
232 
233 	dprintk("NFS: flush(%s/%s)\n",
234 			dentry->d_parent->d_name.name,
235 			dentry->d_name.name);
236 
237 	if ((file->f_mode & FMODE_WRITE) == 0)
238 		return 0;
239 	nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
240 
241 	/* Flush writes to the server and return any errors */
242 	return nfs_do_fsync(ctx, inode);
243 }
244 
245 static ssize_t
246 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
247 		unsigned long nr_segs, loff_t pos)
248 {
249 	struct dentry * dentry = iocb->ki_filp->f_path.dentry;
250 	struct inode * inode = dentry->d_inode;
251 	ssize_t result;
252 	size_t count = iov_length(iov, nr_segs);
253 
254 	if (iocb->ki_filp->f_flags & O_DIRECT)
255 		return nfs_file_direct_read(iocb, iov, nr_segs, pos);
256 
257 	dprintk("NFS: read(%s/%s, %lu@%lu)\n",
258 		dentry->d_parent->d_name.name, dentry->d_name.name,
259 		(unsigned long) count, (unsigned long) pos);
260 
261 	result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
262 	nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
263 	if (!result)
264 		result = generic_file_aio_read(iocb, iov, nr_segs, pos);
265 	return result;
266 }
267 
268 static ssize_t
269 nfs_file_splice_read(struct file *filp, loff_t *ppos,
270 		     struct pipe_inode_info *pipe, size_t count,
271 		     unsigned int flags)
272 {
273 	struct dentry *dentry = filp->f_path.dentry;
274 	struct inode *inode = dentry->d_inode;
275 	ssize_t res;
276 
277 	dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n",
278 		dentry->d_parent->d_name.name, dentry->d_name.name,
279 		(unsigned long) count, (unsigned long long) *ppos);
280 
281 	res = nfs_revalidate_mapping(inode, filp->f_mapping);
282 	if (!res)
283 		res = generic_file_splice_read(filp, ppos, pipe, count, flags);
284 	return res;
285 }
286 
287 static int
288 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
289 {
290 	struct dentry *dentry = file->f_path.dentry;
291 	struct inode *inode = dentry->d_inode;
292 	int	status;
293 
294 	dprintk("NFS: mmap(%s/%s)\n",
295 		dentry->d_parent->d_name.name, dentry->d_name.name);
296 
297 	/* Note: generic_file_mmap() returns ENOSYS on nommu systems
298 	 *       so we call that before revalidating the mapping
299 	 */
300 	status = generic_file_mmap(file, vma);
301 	if (!status) {
302 		vma->vm_ops = &nfs_file_vm_ops;
303 		status = nfs_revalidate_mapping(inode, file->f_mapping);
304 	}
305 	return status;
306 }
307 
308 /*
309  * Flush any dirty pages for this process, and check for write errors.
310  * The return status from this call provides a reliable indication of
311  * whether any write errors occurred for this process.
312  */
313 static int
314 nfs_file_fsync(struct file *file, struct dentry *dentry, int datasync)
315 {
316 	struct nfs_open_context *ctx = nfs_file_open_context(file);
317 	struct inode *inode = dentry->d_inode;
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 	nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
324 	return nfs_do_fsync(ctx, inode);
325 }
326 
327 /*
328  * This does the "real" work of the write. We must allocate and lock the
329  * page to be sent back to the generic routine, which then copies the
330  * data from user space.
331  *
332  * If the writer ends up delaying the write, the writer needs to
333  * increment the page use counts until he is done with the page.
334  */
335 static int nfs_write_begin(struct file *file, struct address_space *mapping,
336 			loff_t pos, unsigned len, unsigned flags,
337 			struct page **pagep, void **fsdata)
338 {
339 	int ret;
340 	pgoff_t index;
341 	struct page *page;
342 	index = pos >> PAGE_CACHE_SHIFT;
343 
344 	dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n",
345 		file->f_path.dentry->d_parent->d_name.name,
346 		file->f_path.dentry->d_name.name,
347 		mapping->host->i_ino, len, (long long) pos);
348 
349 	/*
350 	 * Prevent starvation issues if someone is doing a consistency
351 	 * sync-to-disk
352 	 */
353 	ret = wait_on_bit(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
354 			nfs_wait_bit_killable, TASK_KILLABLE);
355 	if (ret)
356 		return ret;
357 
358 	page = grab_cache_page_write_begin(mapping, index, flags);
359 	if (!page)
360 		return -ENOMEM;
361 	*pagep = page;
362 
363 	ret = nfs_flush_incompatible(file, page);
364 	if (ret) {
365 		unlock_page(page);
366 		page_cache_release(page);
367 	}
368 	return ret;
369 }
370 
371 static int nfs_write_end(struct file *file, struct address_space *mapping,
372 			loff_t pos, unsigned len, unsigned copied,
373 			struct page *page, void *fsdata)
374 {
375 	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
376 	int status;
377 
378 	dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n",
379 		file->f_path.dentry->d_parent->d_name.name,
380 		file->f_path.dentry->d_name.name,
381 		mapping->host->i_ino, len, (long long) pos);
382 
383 	/*
384 	 * Zero any uninitialised parts of the page, and then mark the page
385 	 * as up to date if it turns out that we're extending the file.
386 	 */
387 	if (!PageUptodate(page)) {
388 		unsigned pglen = nfs_page_length(page);
389 		unsigned end = offset + len;
390 
391 		if (pglen == 0) {
392 			zero_user_segments(page, 0, offset,
393 					end, PAGE_CACHE_SIZE);
394 			SetPageUptodate(page);
395 		} else if (end >= pglen) {
396 			zero_user_segment(page, end, PAGE_CACHE_SIZE);
397 			if (offset == 0)
398 				SetPageUptodate(page);
399 		} else
400 			zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
401 	}
402 
403 	status = nfs_updatepage(file, page, offset, copied);
404 
405 	unlock_page(page);
406 	page_cache_release(page);
407 
408 	if (status < 0)
409 		return status;
410 	return copied;
411 }
412 
413 /*
414  * Partially or wholly invalidate a page
415  * - Release the private state associated with a page if undergoing complete
416  *   page invalidation
417  * - Called if either PG_private or PG_fscache is set on the page
418  * - Caller holds page lock
419  */
420 static void nfs_invalidate_page(struct page *page, unsigned long offset)
421 {
422 	dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
423 
424 	if (offset != 0)
425 		return;
426 	/* Cancel any unstarted writes on this page */
427 	nfs_wb_page_cancel(page->mapping->host, page);
428 
429 	nfs_fscache_invalidate_page(page, page->mapping->host);
430 }
431 
432 /*
433  * Attempt to release the private state associated with a page
434  * - Called if either PG_private or PG_fscache is set on the page
435  * - Caller holds page lock
436  * - Return true (may release page) or false (may not)
437  */
438 static int nfs_release_page(struct page *page, gfp_t gfp)
439 {
440 	dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
441 
442 	/* If PagePrivate() is set, then the page is not freeable */
443 	if (PagePrivate(page))
444 		return 0;
445 	return nfs_fscache_release_page(page, gfp);
446 }
447 
448 /*
449  * Attempt to clear the private state associated with a page when an error
450  * occurs that requires the cached contents of an inode to be written back or
451  * destroyed
452  * - Called if either PG_private or fscache is set on the page
453  * - Caller holds page lock
454  * - Return 0 if successful, -error otherwise
455  */
456 static int nfs_launder_page(struct page *page)
457 {
458 	struct inode *inode = page->mapping->host;
459 	struct nfs_inode *nfsi = NFS_I(inode);
460 
461 	dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
462 		inode->i_ino, (long long)page_offset(page));
463 
464 	nfs_fscache_wait_on_page_write(nfsi, page);
465 	return nfs_wb_page(inode, page);
466 }
467 
468 const struct address_space_operations nfs_file_aops = {
469 	.readpage = nfs_readpage,
470 	.readpages = nfs_readpages,
471 	.set_page_dirty = __set_page_dirty_nobuffers,
472 	.writepage = nfs_writepage,
473 	.writepages = nfs_writepages,
474 	.write_begin = nfs_write_begin,
475 	.write_end = nfs_write_end,
476 	.invalidatepage = nfs_invalidate_page,
477 	.releasepage = nfs_release_page,
478 	.direct_IO = nfs_direct_IO,
479 	.launder_page = nfs_launder_page,
480 };
481 
482 /*
483  * Notification that a PTE pointing to an NFS page is about to be made
484  * writable, implying that someone is about to modify the page through a
485  * shared-writable mapping
486  */
487 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
488 {
489 	struct page *page = vmf->page;
490 	struct file *filp = vma->vm_file;
491 	struct dentry *dentry = filp->f_path.dentry;
492 	unsigned pagelen;
493 	int ret = -EINVAL;
494 	struct address_space *mapping;
495 
496 	dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
497 		dentry->d_parent->d_name.name, dentry->d_name.name,
498 		filp->f_mapping->host->i_ino,
499 		(long long)page_offset(page));
500 
501 	/* make sure the cache has finished storing the page */
502 	nfs_fscache_wait_on_page_write(NFS_I(dentry->d_inode), page);
503 
504 	lock_page(page);
505 	mapping = page->mapping;
506 	if (mapping != dentry->d_inode->i_mapping)
507 		goto out_unlock;
508 
509 	ret = 0;
510 	pagelen = nfs_page_length(page);
511 	if (pagelen == 0)
512 		goto out_unlock;
513 
514 	ret = nfs_flush_incompatible(filp, page);
515 	if (ret != 0)
516 		goto out_unlock;
517 
518 	ret = nfs_updatepage(filp, page, 0, pagelen);
519 out_unlock:
520 	if (!ret)
521 		return VM_FAULT_LOCKED;
522 	unlock_page(page);
523 	return VM_FAULT_SIGBUS;
524 }
525 
526 static struct vm_operations_struct nfs_file_vm_ops = {
527 	.fault = filemap_fault,
528 	.page_mkwrite = nfs_vm_page_mkwrite,
529 };
530 
531 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
532 {
533 	struct nfs_open_context *ctx;
534 
535 	if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
536 		return 1;
537 	ctx = nfs_file_open_context(filp);
538 	if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
539 		return 1;
540 	return 0;
541 }
542 
543 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
544 				unsigned long nr_segs, loff_t pos)
545 {
546 	struct dentry * dentry = iocb->ki_filp->f_path.dentry;
547 	struct inode * inode = dentry->d_inode;
548 	ssize_t result;
549 	size_t count = iov_length(iov, nr_segs);
550 
551 	if (iocb->ki_filp->f_flags & O_DIRECT)
552 		return nfs_file_direct_write(iocb, iov, nr_segs, pos);
553 
554 	dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
555 		dentry->d_parent->d_name.name, dentry->d_name.name,
556 		(unsigned long) count, (long long) pos);
557 
558 	result = -EBUSY;
559 	if (IS_SWAPFILE(inode))
560 		goto out_swapfile;
561 	/*
562 	 * O_APPEND implies that we must revalidate the file length.
563 	 */
564 	if (iocb->ki_filp->f_flags & O_APPEND) {
565 		result = nfs_revalidate_file_size(inode, iocb->ki_filp);
566 		if (result)
567 			goto out;
568 	}
569 
570 	result = count;
571 	if (!count)
572 		goto out;
573 
574 	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
575 	result = generic_file_aio_write(iocb, iov, nr_segs, pos);
576 	/* Return error values for O_SYNC and IS_SYNC() */
577 	if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
578 		int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
579 		if (err < 0)
580 			result = err;
581 	}
582 out:
583 	return result;
584 
585 out_swapfile:
586 	printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
587 	goto out;
588 }
589 
590 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
591 {
592 	struct inode *inode = filp->f_mapping->host;
593 	int status = 0;
594 
595 	lock_kernel();
596 	/* Try local locking first */
597 	posix_test_lock(filp, fl);
598 	if (fl->fl_type != F_UNLCK) {
599 		/* found a conflict */
600 		goto out;
601 	}
602 
603 	if (nfs_have_delegation(inode, FMODE_READ))
604 		goto out_noconflict;
605 
606 	if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
607 		goto out_noconflict;
608 
609 	status = NFS_PROTO(inode)->lock(filp, cmd, fl);
610 out:
611 	unlock_kernel();
612 	return status;
613 out_noconflict:
614 	fl->fl_type = F_UNLCK;
615 	goto out;
616 }
617 
618 static int do_vfs_lock(struct file *file, struct file_lock *fl)
619 {
620 	int res = 0;
621 	switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
622 		case FL_POSIX:
623 			res = posix_lock_file_wait(file, fl);
624 			break;
625 		case FL_FLOCK:
626 			res = flock_lock_file_wait(file, fl);
627 			break;
628 		default:
629 			BUG();
630 	}
631 	if (res < 0)
632 		dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
633 			" - error %d!\n",
634 				__func__, res);
635 	return res;
636 }
637 
638 static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
639 {
640 	struct inode *inode = filp->f_mapping->host;
641 	int status;
642 
643 	/*
644 	 * Flush all pending writes before doing anything
645 	 * with locks..
646 	 */
647 	nfs_sync_mapping(filp->f_mapping);
648 
649 	/* NOTE: special case
650 	 * 	If we're signalled while cleaning up locks on process exit, we
651 	 * 	still need to complete the unlock.
652 	 */
653 	lock_kernel();
654 	/* Use local locking if mounted with "-onolock" */
655 	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
656 		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
657 	else
658 		status = do_vfs_lock(filp, fl);
659 	unlock_kernel();
660 	return status;
661 }
662 
663 static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
664 {
665 	struct inode *inode = filp->f_mapping->host;
666 	int status;
667 
668 	/*
669 	 * Flush all pending writes before doing anything
670 	 * with locks..
671 	 */
672 	status = nfs_sync_mapping(filp->f_mapping);
673 	if (status != 0)
674 		goto out;
675 
676 	lock_kernel();
677 	/* Use local locking if mounted with "-onolock" */
678 	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
679 		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
680 	else
681 		status = do_vfs_lock(filp, fl);
682 	unlock_kernel();
683 	if (status < 0)
684 		goto out;
685 	/*
686 	 * Make sure we clear the cache whenever we try to get the lock.
687 	 * This makes locking act as a cache coherency point.
688 	 */
689 	nfs_sync_mapping(filp->f_mapping);
690 	if (!nfs_have_delegation(inode, FMODE_READ))
691 		nfs_zap_caches(inode);
692 out:
693 	return status;
694 }
695 
696 /*
697  * Lock a (portion of) a file
698  */
699 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
700 {
701 	struct inode *inode = filp->f_mapping->host;
702 	int ret = -ENOLCK;
703 
704 	dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n",
705 			filp->f_path.dentry->d_parent->d_name.name,
706 			filp->f_path.dentry->d_name.name,
707 			fl->fl_type, fl->fl_flags,
708 			(long long)fl->fl_start, (long long)fl->fl_end);
709 
710 	nfs_inc_stats(inode, NFSIOS_VFSLOCK);
711 
712 	/* No mandatory locks over NFS */
713 	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
714 		goto out_err;
715 
716 	if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
717 		ret = NFS_PROTO(inode)->lock_check_bounds(fl);
718 		if (ret < 0)
719 			goto out_err;
720 	}
721 
722 	if (IS_GETLK(cmd))
723 		ret = do_getlk(filp, cmd, fl);
724 	else if (fl->fl_type == F_UNLCK)
725 		ret = do_unlk(filp, cmd, fl);
726 	else
727 		ret = do_setlk(filp, cmd, fl);
728 out_err:
729 	return ret;
730 }
731 
732 /*
733  * Lock a (portion of) a file
734  */
735 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
736 {
737 	dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n",
738 			filp->f_path.dentry->d_parent->d_name.name,
739 			filp->f_path.dentry->d_name.name,
740 			fl->fl_type, fl->fl_flags);
741 
742 	if (!(fl->fl_flags & FL_FLOCK))
743 		return -ENOLCK;
744 
745 	/* We're simulating flock() locks using posix locks on the server */
746 	fl->fl_owner = (fl_owner_t)filp;
747 	fl->fl_start = 0;
748 	fl->fl_end = OFFSET_MAX;
749 
750 	if (fl->fl_type == F_UNLCK)
751 		return do_unlk(filp, cmd, fl);
752 	return do_setlk(filp, cmd, fl);
753 }
754 
755 /*
756  * There is no protocol support for leases, so we have no way to implement
757  * them correctly in the face of opens by other clients.
758  */
759 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
760 {
761 	dprintk("NFS: setlease(%s/%s, arg=%ld)\n",
762 			file->f_path.dentry->d_parent->d_name.name,
763 			file->f_path.dentry->d_name.name, arg);
764 
765 	return -EINVAL;
766 }
767