xref: /openbmc/linux/fs/nfs/file.c (revision 367b8112)
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 
39 #define NFSDBG_FACILITY		NFSDBG_FILE
40 
41 static int nfs_file_open(struct inode *, struct file *);
42 static int nfs_file_release(struct inode *, struct file *);
43 static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin);
44 static int  nfs_file_mmap(struct file *, struct vm_area_struct *);
45 static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos,
46 					struct pipe_inode_info *pipe,
47 					size_t count, unsigned int flags);
48 static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov,
49 				unsigned long nr_segs, loff_t pos);
50 static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov,
51 				unsigned long nr_segs, loff_t pos);
52 static int  nfs_file_flush(struct file *, fl_owner_t id);
53 static int  nfs_file_fsync(struct file *, struct dentry *dentry, int datasync);
54 static int nfs_check_flags(int flags);
55 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl);
56 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl);
57 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl);
58 
59 static struct vm_operations_struct nfs_file_vm_ops;
60 
61 const struct file_operations nfs_file_operations = {
62 	.llseek		= nfs_file_llseek,
63 	.read		= do_sync_read,
64 	.write		= do_sync_write,
65 	.aio_read	= nfs_file_read,
66 	.aio_write	= nfs_file_write,
67 #ifdef CONFIG_MMU
68 	.mmap		= nfs_file_mmap,
69 #else
70 	.mmap		= generic_file_mmap,
71 #endif
72 	.open		= nfs_file_open,
73 	.flush		= nfs_file_flush,
74 	.release	= nfs_file_release,
75 	.fsync		= nfs_file_fsync,
76 	.lock		= nfs_lock,
77 	.flock		= nfs_flock,
78 	.splice_read	= nfs_file_splice_read,
79 	.check_flags	= nfs_check_flags,
80 	.setlease	= nfs_setlease,
81 };
82 
83 const struct inode_operations nfs_file_inode_operations = {
84 	.permission	= nfs_permission,
85 	.getattr	= nfs_getattr,
86 	.setattr	= nfs_setattr,
87 };
88 
89 #ifdef CONFIG_NFS_V3
90 const struct inode_operations nfs3_file_inode_operations = {
91 	.permission	= nfs_permission,
92 	.getattr	= nfs_getattr,
93 	.setattr	= nfs_setattr,
94 	.listxattr	= nfs3_listxattr,
95 	.getxattr	= nfs3_getxattr,
96 	.setxattr	= nfs3_setxattr,
97 	.removexattr	= nfs3_removexattr,
98 };
99 #endif  /* CONFIG_NFS_v3 */
100 
101 /* Hack for future NFS swap support */
102 #ifndef IS_SWAPFILE
103 # define IS_SWAPFILE(inode)	(0)
104 #endif
105 
106 static int nfs_check_flags(int flags)
107 {
108 	if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
109 		return -EINVAL;
110 
111 	return 0;
112 }
113 
114 /*
115  * Open file
116  */
117 static int
118 nfs_file_open(struct inode *inode, struct file *filp)
119 {
120 	int res;
121 
122 	dprintk("NFS: open file(%s/%s)\n",
123 			filp->f_path.dentry->d_parent->d_name.name,
124 			filp->f_path.dentry->d_name.name);
125 
126 	res = nfs_check_flags(filp->f_flags);
127 	if (res)
128 		return res;
129 
130 	nfs_inc_stats(inode, NFSIOS_VFSOPEN);
131 	res = nfs_open(inode, filp);
132 	return res;
133 }
134 
135 static int
136 nfs_file_release(struct inode *inode, struct file *filp)
137 {
138 	struct dentry *dentry = filp->f_path.dentry;
139 
140 	dprintk("NFS: release(%s/%s)\n",
141 			dentry->d_parent->d_name.name,
142 			dentry->d_name.name);
143 
144 	/* Ensure that dirty pages are flushed out with the right creds */
145 	if (filp->f_mode & FMODE_WRITE)
146 		nfs_wb_all(dentry->d_inode);
147 	nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
148 	return nfs_release(inode, filp);
149 }
150 
151 /**
152  * nfs_revalidate_size - Revalidate the file size
153  * @inode - pointer to inode struct
154  * @file - pointer to struct file
155  *
156  * Revalidates the file length. This is basically a wrapper around
157  * nfs_revalidate_inode() that takes into account the fact that we may
158  * have cached writes (in which case we don't care about the server's
159  * idea of what the file length is), or O_DIRECT (in which case we
160  * shouldn't trust the cache).
161  */
162 static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
163 {
164 	struct nfs_server *server = NFS_SERVER(inode);
165 	struct nfs_inode *nfsi = NFS_I(inode);
166 
167 	if (server->flags & NFS_MOUNT_NOAC)
168 		goto force_reval;
169 	if (filp->f_flags & O_DIRECT)
170 		goto force_reval;
171 	if (nfsi->npages != 0)
172 		return 0;
173 	if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode))
174 		return 0;
175 force_reval:
176 	return __nfs_revalidate_inode(server, inode);
177 }
178 
179 static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin)
180 {
181 	loff_t loff;
182 
183 	dprintk("NFS: llseek file(%s/%s, %lld, %d)\n",
184 			filp->f_path.dentry->d_parent->d_name.name,
185 			filp->f_path.dentry->d_name.name,
186 			offset, origin);
187 
188 	/* origin == SEEK_END => we must revalidate the cached file length */
189 	if (origin == SEEK_END) {
190 		struct inode *inode = filp->f_mapping->host;
191 
192 		int retval = nfs_revalidate_file_size(inode, filp);
193 		if (retval < 0)
194 			return (loff_t)retval;
195 
196 		spin_lock(&inode->i_lock);
197 		loff = generic_file_llseek_unlocked(filp, offset, origin);
198 		spin_unlock(&inode->i_lock);
199 	} else
200 		loff = generic_file_llseek_unlocked(filp, offset, origin);
201 	return loff;
202 }
203 
204 /*
205  * Helper for nfs_file_flush() and nfs_file_fsync()
206  *
207  * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
208  * disk, but it retrieves and clears ctx->error after synching, despite
209  * the two being set at the same time in nfs_context_set_write_error().
210  * This is because the former is used to notify the _next_ call to
211  * nfs_file_write() that a write error occured, and hence cause it to
212  * fall back to doing a synchronous write.
213  */
214 static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode)
215 {
216 	int have_error, status;
217 	int ret = 0;
218 
219 	have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
220 	status = nfs_wb_all(inode);
221 	have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
222 	if (have_error)
223 		ret = xchg(&ctx->error, 0);
224 	if (!ret)
225 		ret = status;
226 	return ret;
227 }
228 
229 /*
230  * Flush all dirty pages, and check for write errors.
231  */
232 static int
233 nfs_file_flush(struct file *file, fl_owner_t id)
234 {
235 	struct nfs_open_context *ctx = nfs_file_open_context(file);
236 	struct dentry	*dentry = file->f_path.dentry;
237 	struct inode	*inode = dentry->d_inode;
238 	int		status;
239 
240 	dprintk("NFS: flush(%s/%s)\n",
241 			dentry->d_parent->d_name.name,
242 			dentry->d_name.name);
243 
244 	if ((file->f_mode & FMODE_WRITE) == 0)
245 		return 0;
246 	nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
247 
248 	/* Ensure that data+attribute caches are up to date after close() */
249 	status = nfs_do_fsync(ctx, inode);
250 	if (!status)
251 		nfs_revalidate_inode(NFS_SERVER(inode), inode);
252 	return status;
253 }
254 
255 static ssize_t
256 nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
257 		unsigned long nr_segs, loff_t pos)
258 {
259 	struct dentry * dentry = iocb->ki_filp->f_path.dentry;
260 	struct inode * inode = dentry->d_inode;
261 	ssize_t result;
262 	size_t count = iov_length(iov, nr_segs);
263 
264 	if (iocb->ki_filp->f_flags & O_DIRECT)
265 		return nfs_file_direct_read(iocb, iov, nr_segs, pos);
266 
267 	dprintk("NFS: read(%s/%s, %lu@%lu)\n",
268 		dentry->d_parent->d_name.name, dentry->d_name.name,
269 		(unsigned long) count, (unsigned long) pos);
270 
271 	result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
272 	nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count);
273 	if (!result)
274 		result = generic_file_aio_read(iocb, iov, nr_segs, pos);
275 	return result;
276 }
277 
278 static ssize_t
279 nfs_file_splice_read(struct file *filp, loff_t *ppos,
280 		     struct pipe_inode_info *pipe, size_t count,
281 		     unsigned int flags)
282 {
283 	struct dentry *dentry = filp->f_path.dentry;
284 	struct inode *inode = dentry->d_inode;
285 	ssize_t res;
286 
287 	dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n",
288 		dentry->d_parent->d_name.name, dentry->d_name.name,
289 		(unsigned long) count, (unsigned long long) *ppos);
290 
291 	res = nfs_revalidate_mapping(inode, filp->f_mapping);
292 	if (!res)
293 		res = generic_file_splice_read(filp, ppos, pipe, count, flags);
294 	return res;
295 }
296 
297 static int
298 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
299 {
300 	struct dentry *dentry = file->f_path.dentry;
301 	struct inode *inode = dentry->d_inode;
302 	int	status;
303 
304 	dprintk("NFS: mmap(%s/%s)\n",
305 		dentry->d_parent->d_name.name, dentry->d_name.name);
306 
307 	status = nfs_revalidate_mapping(inode, file->f_mapping);
308 	if (!status) {
309 		vma->vm_ops = &nfs_file_vm_ops;
310 		vma->vm_flags |= VM_CAN_NONLINEAR;
311 		file_accessed(file);
312 	}
313 	return status;
314 }
315 
316 /*
317  * Flush any dirty pages for this process, and check for write errors.
318  * The return status from this call provides a reliable indication of
319  * whether any write errors occurred for this process.
320  */
321 static int
322 nfs_file_fsync(struct file *file, struct dentry *dentry, int datasync)
323 {
324 	struct nfs_open_context *ctx = nfs_file_open_context(file);
325 	struct inode *inode = dentry->d_inode;
326 
327 	dprintk("NFS: fsync file(%s/%s) datasync %d\n",
328 			dentry->d_parent->d_name.name, dentry->d_name.name,
329 			datasync);
330 
331 	nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
332 	return nfs_do_fsync(ctx, inode);
333 }
334 
335 /*
336  * This does the "real" work of the write. We must allocate and lock the
337  * page to be sent back to the generic routine, which then copies the
338  * data from user space.
339  *
340  * If the writer ends up delaying the write, the writer needs to
341  * increment the page use counts until he is done with the page.
342  */
343 static int nfs_write_begin(struct file *file, struct address_space *mapping,
344 			loff_t pos, unsigned len, unsigned flags,
345 			struct page **pagep, void **fsdata)
346 {
347 	int ret;
348 	pgoff_t index;
349 	struct page *page;
350 	index = pos >> PAGE_CACHE_SHIFT;
351 
352 	dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n",
353 		file->f_path.dentry->d_parent->d_name.name,
354 		file->f_path.dentry->d_name.name,
355 		mapping->host->i_ino, len, (long long) pos);
356 
357 	page = __grab_cache_page(mapping, index);
358 	if (!page)
359 		return -ENOMEM;
360 	*pagep = page;
361 
362 	ret = nfs_flush_incompatible(file, page);
363 	if (ret) {
364 		unlock_page(page);
365 		page_cache_release(page);
366 	}
367 	return ret;
368 }
369 
370 static int nfs_write_end(struct file *file, struct address_space *mapping,
371 			loff_t pos, unsigned len, unsigned copied,
372 			struct page *page, void *fsdata)
373 {
374 	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
375 	int status;
376 
377 	dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n",
378 		file->f_path.dentry->d_parent->d_name.name,
379 		file->f_path.dentry->d_name.name,
380 		mapping->host->i_ino, len, (long long) pos);
381 
382 	/*
383 	 * Zero any uninitialised parts of the page, and then mark the page
384 	 * as up to date if it turns out that we're extending the file.
385 	 */
386 	if (!PageUptodate(page)) {
387 		unsigned pglen = nfs_page_length(page);
388 		unsigned end = offset + len;
389 
390 		if (pglen == 0) {
391 			zero_user_segments(page, 0, offset,
392 					end, PAGE_CACHE_SIZE);
393 			SetPageUptodate(page);
394 		} else if (end >= pglen) {
395 			zero_user_segment(page, end, PAGE_CACHE_SIZE);
396 			if (offset == 0)
397 				SetPageUptodate(page);
398 		} else
399 			zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
400 	}
401 
402 	status = nfs_updatepage(file, page, offset, copied);
403 
404 	unlock_page(page);
405 	page_cache_release(page);
406 
407 	if (status < 0)
408 		return status;
409 	return copied;
410 }
411 
412 static void nfs_invalidate_page(struct page *page, unsigned long offset)
413 {
414 	dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset);
415 
416 	if (offset != 0)
417 		return;
418 	/* Cancel any unstarted writes on this page */
419 	nfs_wb_page_cancel(page->mapping->host, page);
420 }
421 
422 static int nfs_release_page(struct page *page, gfp_t gfp)
423 {
424 	dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
425 
426 	/* If PagePrivate() is set, then the page is not freeable */
427 	return 0;
428 }
429 
430 static int nfs_launder_page(struct page *page)
431 {
432 	struct inode *inode = page->mapping->host;
433 
434 	dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
435 		inode->i_ino, (long long)page_offset(page));
436 
437 	return nfs_wb_page(inode, page);
438 }
439 
440 const struct address_space_operations nfs_file_aops = {
441 	.readpage = nfs_readpage,
442 	.readpages = nfs_readpages,
443 	.set_page_dirty = __set_page_dirty_nobuffers,
444 	.writepage = nfs_writepage,
445 	.writepages = nfs_writepages,
446 	.write_begin = nfs_write_begin,
447 	.write_end = nfs_write_end,
448 	.invalidatepage = nfs_invalidate_page,
449 	.releasepage = nfs_release_page,
450 	.direct_IO = nfs_direct_IO,
451 	.launder_page = nfs_launder_page,
452 };
453 
454 static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
455 {
456 	struct file *filp = vma->vm_file;
457 	struct dentry *dentry = filp->f_path.dentry;
458 	unsigned pagelen;
459 	int ret = -EINVAL;
460 	struct address_space *mapping;
461 
462 	dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n",
463 		dentry->d_parent->d_name.name, dentry->d_name.name,
464 		filp->f_mapping->host->i_ino,
465 		(long long)page_offset(page));
466 
467 	lock_page(page);
468 	mapping = page->mapping;
469 	if (mapping != dentry->d_inode->i_mapping)
470 		goto out_unlock;
471 
472 	ret = 0;
473 	pagelen = nfs_page_length(page);
474 	if (pagelen == 0)
475 		goto out_unlock;
476 
477 	ret = nfs_flush_incompatible(filp, page);
478 	if (ret != 0)
479 		goto out_unlock;
480 
481 	ret = nfs_updatepage(filp, page, 0, pagelen);
482 	if (ret == 0)
483 		ret = pagelen;
484 out_unlock:
485 	unlock_page(page);
486 	return ret;
487 }
488 
489 static struct vm_operations_struct nfs_file_vm_ops = {
490 	.fault = filemap_fault,
491 	.page_mkwrite = nfs_vm_page_mkwrite,
492 };
493 
494 static int nfs_need_sync_write(struct file *filp, struct inode *inode)
495 {
496 	struct nfs_open_context *ctx;
497 
498 	if (IS_SYNC(inode) || (filp->f_flags & O_SYNC))
499 		return 1;
500 	ctx = nfs_file_open_context(filp);
501 	if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags))
502 		return 1;
503 	return 0;
504 }
505 
506 static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
507 				unsigned long nr_segs, loff_t pos)
508 {
509 	struct dentry * dentry = iocb->ki_filp->f_path.dentry;
510 	struct inode * inode = dentry->d_inode;
511 	ssize_t result;
512 	size_t count = iov_length(iov, nr_segs);
513 
514 	if (iocb->ki_filp->f_flags & O_DIRECT)
515 		return nfs_file_direct_write(iocb, iov, nr_segs, pos);
516 
517 	dprintk("NFS: write(%s/%s, %lu@%Ld)\n",
518 		dentry->d_parent->d_name.name, dentry->d_name.name,
519 		(unsigned long) count, (long long) pos);
520 
521 	result = -EBUSY;
522 	if (IS_SWAPFILE(inode))
523 		goto out_swapfile;
524 	/*
525 	 * O_APPEND implies that we must revalidate the file length.
526 	 */
527 	if (iocb->ki_filp->f_flags & O_APPEND) {
528 		result = nfs_revalidate_file_size(inode, iocb->ki_filp);
529 		if (result)
530 			goto out;
531 	}
532 
533 	result = count;
534 	if (!count)
535 		goto out;
536 
537 	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count);
538 	result = generic_file_aio_write(iocb, iov, nr_segs, pos);
539 	/* Return error values for O_SYNC and IS_SYNC() */
540 	if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) {
541 		int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode);
542 		if (err < 0)
543 			result = err;
544 	}
545 out:
546 	return result;
547 
548 out_swapfile:
549 	printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
550 	goto out;
551 }
552 
553 static int do_getlk(struct file *filp, int cmd, struct file_lock *fl)
554 {
555 	struct inode *inode = filp->f_mapping->host;
556 	int status = 0;
557 
558 	lock_kernel();
559 	/* Try local locking first */
560 	posix_test_lock(filp, fl);
561 	if (fl->fl_type != F_UNLCK) {
562 		/* found a conflict */
563 		goto out;
564 	}
565 
566 	if (nfs_have_delegation(inode, FMODE_READ))
567 		goto out_noconflict;
568 
569 	if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)
570 		goto out_noconflict;
571 
572 	status = NFS_PROTO(inode)->lock(filp, cmd, fl);
573 out:
574 	unlock_kernel();
575 	return status;
576 out_noconflict:
577 	fl->fl_type = F_UNLCK;
578 	goto out;
579 }
580 
581 static int do_vfs_lock(struct file *file, struct file_lock *fl)
582 {
583 	int res = 0;
584 	switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
585 		case FL_POSIX:
586 			res = posix_lock_file_wait(file, fl);
587 			break;
588 		case FL_FLOCK:
589 			res = flock_lock_file_wait(file, fl);
590 			break;
591 		default:
592 			BUG();
593 	}
594 	if (res < 0)
595 		dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager"
596 			" - error %d!\n",
597 				__func__, res);
598 	return res;
599 }
600 
601 static int do_unlk(struct file *filp, int cmd, struct file_lock *fl)
602 {
603 	struct inode *inode = filp->f_mapping->host;
604 	int status;
605 
606 	/*
607 	 * Flush all pending writes before doing anything
608 	 * with locks..
609 	 */
610 	nfs_sync_mapping(filp->f_mapping);
611 
612 	/* NOTE: special case
613 	 * 	If we're signalled while cleaning up locks on process exit, we
614 	 * 	still need to complete the unlock.
615 	 */
616 	lock_kernel();
617 	/* Use local locking if mounted with "-onolock" */
618 	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
619 		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
620 	else
621 		status = do_vfs_lock(filp, fl);
622 	unlock_kernel();
623 	return status;
624 }
625 
626 static int do_setlk(struct file *filp, int cmd, struct file_lock *fl)
627 {
628 	struct inode *inode = filp->f_mapping->host;
629 	int status;
630 
631 	/*
632 	 * Flush all pending writes before doing anything
633 	 * with locks..
634 	 */
635 	status = nfs_sync_mapping(filp->f_mapping);
636 	if (status != 0)
637 		goto out;
638 
639 	lock_kernel();
640 	/* Use local locking if mounted with "-onolock" */
641 	if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM))
642 		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
643 	else
644 		status = do_vfs_lock(filp, fl);
645 	unlock_kernel();
646 	if (status < 0)
647 		goto out;
648 	/*
649 	 * Make sure we clear the cache whenever we try to get the lock.
650 	 * This makes locking act as a cache coherency point.
651 	 */
652 	nfs_sync_mapping(filp->f_mapping);
653 	if (!nfs_have_delegation(inode, FMODE_READ))
654 		nfs_zap_caches(inode);
655 out:
656 	return status;
657 }
658 
659 /*
660  * Lock a (portion of) a file
661  */
662 static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
663 {
664 	struct inode *inode = filp->f_mapping->host;
665 	int ret = -ENOLCK;
666 
667 	dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n",
668 			filp->f_path.dentry->d_parent->d_name.name,
669 			filp->f_path.dentry->d_name.name,
670 			fl->fl_type, fl->fl_flags,
671 			(long long)fl->fl_start, (long long)fl->fl_end);
672 
673 	nfs_inc_stats(inode, NFSIOS_VFSLOCK);
674 
675 	/* No mandatory locks over NFS */
676 	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
677 		goto out_err;
678 
679 	if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
680 		ret = NFS_PROTO(inode)->lock_check_bounds(fl);
681 		if (ret < 0)
682 			goto out_err;
683 	}
684 
685 	if (IS_GETLK(cmd))
686 		ret = do_getlk(filp, cmd, fl);
687 	else if (fl->fl_type == F_UNLCK)
688 		ret = do_unlk(filp, cmd, fl);
689 	else
690 		ret = do_setlk(filp, cmd, fl);
691 out_err:
692 	return ret;
693 }
694 
695 /*
696  * Lock a (portion of) a file
697  */
698 static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
699 {
700 	dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n",
701 			filp->f_path.dentry->d_parent->d_name.name,
702 			filp->f_path.dentry->d_name.name,
703 			fl->fl_type, fl->fl_flags);
704 
705 	if (!(fl->fl_flags & FL_FLOCK))
706 		return -ENOLCK;
707 
708 	/* We're simulating flock() locks using posix locks on the server */
709 	fl->fl_owner = (fl_owner_t)filp;
710 	fl->fl_start = 0;
711 	fl->fl_end = OFFSET_MAX;
712 
713 	if (fl->fl_type == F_UNLCK)
714 		return do_unlk(filp, cmd, fl);
715 	return do_setlk(filp, cmd, fl);
716 }
717 
718 /*
719  * There is no protocol support for leases, so we have no way to implement
720  * them correctly in the face of opens by other clients.
721  */
722 static int nfs_setlease(struct file *file, long arg, struct file_lock **fl)
723 {
724 	dprintk("NFS: setlease(%s/%s, arg=%ld)\n",
725 			file->f_path.dentry->d_parent->d_name.name,
726 			file->f_path.dentry->d_name.name, arg);
727 
728 	return -EINVAL;
729 }
730