file.c revision f7e33bdb
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  linux/fs/nfs/file.c
4 *
5 *  Copyright (C) 1992  Rick Sladkey
6 *
7 *  Changes Copyright (C) 1994 by Florian La Roche
8 *   - Do not copy data too often around in the kernel.
9 *   - In nfs_file_read the return value of kmalloc wasn't checked.
10 *   - Put in a better version of read look-ahead buffering. Original idea
11 *     and implementation by Wai S Kok elekokws@ee.nus.sg.
12 *
13 *  Expire cache on write to a file by Wai S Kok (Oct 1994).
14 *
15 *  Total rewrite of read side for new NFS buffer cache.. Linus.
16 *
17 *  nfs regular file handling functions
18 */
19
20#include <linux/module.h>
21#include <linux/time.h>
22#include <linux/kernel.h>
23#include <linux/errno.h>
24#include <linux/fcntl.h>
25#include <linux/stat.h>
26#include <linux/nfs_fs.h>
27#include <linux/nfs_mount.h>
28#include <linux/mm.h>
29#include <linux/pagemap.h>
30#include <linux/gfp.h>
31#include <linux/swap.h>
32
33#include <linux/uaccess.h>
34
35#include "delegation.h"
36#include "internal.h"
37#include "iostat.h"
38#include "fscache.h"
39#include "pnfs.h"
40
41#include "nfstrace.h"
42
43#define NFSDBG_FACILITY		NFSDBG_FILE
44
45static const struct vm_operations_struct nfs_file_vm_ops;
46
47/* Hack for future NFS swap support */
48#ifndef IS_SWAPFILE
49# define IS_SWAPFILE(inode)	(0)
50#endif
51
52int nfs_check_flags(int flags)
53{
54	if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
55		return -EINVAL;
56
57	return 0;
58}
59EXPORT_SYMBOL_GPL(nfs_check_flags);
60
61/*
62 * Open file
63 */
64static int
65nfs_file_open(struct inode *inode, struct file *filp)
66{
67	int res;
68
69	dprintk("NFS: open file(%pD2)\n", filp);
70
71	nfs_inc_stats(inode, NFSIOS_VFSOPEN);
72	res = nfs_check_flags(filp->f_flags);
73	if (res)
74		return res;
75
76	res = nfs_open(inode, filp);
77	return res;
78}
79
80int
81nfs_file_release(struct inode *inode, struct file *filp)
82{
83	dprintk("NFS: release(%pD2)\n", filp);
84
85	nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
86	nfs_file_clear_open_context(filp);
87	return 0;
88}
89EXPORT_SYMBOL_GPL(nfs_file_release);
90
91/**
92 * nfs_revalidate_file_size - Revalidate the file size
93 * @inode: pointer to inode struct
94 * @filp: pointer to struct file
95 *
96 * Revalidates the file length. This is basically a wrapper around
97 * nfs_revalidate_inode() that takes into account the fact that we may
98 * have cached writes (in which case we don't care about the server's
99 * idea of what the file length is), or O_DIRECT (in which case we
100 * shouldn't trust the cache).
101 */
102static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
103{
104	struct nfs_server *server = NFS_SERVER(inode);
105
106	if (filp->f_flags & O_DIRECT)
107		goto force_reval;
108	if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_SIZE))
109		goto force_reval;
110	return 0;
111force_reval:
112	return __nfs_revalidate_inode(server, inode);
113}
114
115loff_t nfs_file_llseek(struct file *filp, loff_t offset, int whence)
116{
117	dprintk("NFS: llseek file(%pD2, %lld, %d)\n",
118			filp, offset, whence);
119
120	/*
121	 * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
122	 * the cached file length
123	 */
124	if (whence != SEEK_SET && whence != SEEK_CUR) {
125		struct inode *inode = filp->f_mapping->host;
126
127		int retval = nfs_revalidate_file_size(inode, filp);
128		if (retval < 0)
129			return (loff_t)retval;
130	}
131
132	return generic_file_llseek(filp, offset, whence);
133}
134EXPORT_SYMBOL_GPL(nfs_file_llseek);
135
136/*
137 * Flush all dirty pages, and check for write errors.
138 */
139static int
140nfs_file_flush(struct file *file, fl_owner_t id)
141{
142	struct inode	*inode = file_inode(file);
143	errseq_t since;
144
145	dprintk("NFS: flush(%pD2)\n", file);
146
147	nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
148	if ((file->f_mode & FMODE_WRITE) == 0)
149		return 0;
150
151	/* Flush writes to the server and return any errors */
152	since = filemap_sample_wb_err(file->f_mapping);
153	nfs_wb_all(inode);
154	return filemap_check_wb_err(file->f_mapping, since);
155}
156
157ssize_t
158nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
159{
160	struct inode *inode = file_inode(iocb->ki_filp);
161	ssize_t result;
162
163	if (iocb->ki_flags & IOCB_DIRECT)
164		return nfs_file_direct_read(iocb, to);
165
166	dprintk("NFS: read(%pD2, %zu@%lu)\n",
167		iocb->ki_filp,
168		iov_iter_count(to), (unsigned long) iocb->ki_pos);
169
170	nfs_start_io_read(inode);
171	result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
172	if (!result) {
173		result = generic_file_read_iter(iocb, to);
174		if (result > 0)
175			nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
176	}
177	nfs_end_io_read(inode);
178	return result;
179}
180EXPORT_SYMBOL_GPL(nfs_file_read);
181
182int
183nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
184{
185	struct inode *inode = file_inode(file);
186	int	status;
187
188	dprintk("NFS: mmap(%pD2)\n", file);
189
190	/* Note: generic_file_mmap() returns ENOSYS on nommu systems
191	 *       so we call that before revalidating the mapping
192	 */
193	status = generic_file_mmap(file, vma);
194	if (!status) {
195		vma->vm_ops = &nfs_file_vm_ops;
196		status = nfs_revalidate_mapping(inode, file->f_mapping);
197	}
198	return status;
199}
200EXPORT_SYMBOL_GPL(nfs_file_mmap);
201
202/*
203 * Flush any dirty pages for this process, and check for write errors.
204 * The return status from this call provides a reliable indication of
205 * whether any write errors occurred for this process.
206 */
207static int
208nfs_file_fsync_commit(struct file *file, int datasync)
209{
210	struct inode *inode = file_inode(file);
211	int ret;
212
213	dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
214
215	nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
216	ret = nfs_commit_inode(inode, FLUSH_SYNC);
217	if (ret < 0)
218		return ret;
219	return file_check_and_advance_wb_err(file);
220}
221
222int
223nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
224{
225	struct nfs_open_context *ctx = nfs_file_open_context(file);
226	struct inode *inode = file_inode(file);
227	int ret;
228
229	trace_nfs_fsync_enter(inode);
230
231	for (;;) {
232		ret = file_write_and_wait_range(file, start, end);
233		if (ret != 0)
234			break;
235		ret = nfs_file_fsync_commit(file, datasync);
236		if (ret != 0)
237			break;
238		ret = pnfs_sync_inode(inode, !!datasync);
239		if (ret != 0)
240			break;
241		if (!test_and_clear_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags))
242			break;
243		/*
244		 * If nfs_file_fsync_commit detected a server reboot, then
245		 * resend all dirty pages that might have been covered by
246		 * the NFS_CONTEXT_RESEND_WRITES flag
247		 */
248		start = 0;
249		end = LLONG_MAX;
250	}
251
252	trace_nfs_fsync_exit(inode, ret);
253	return ret;
254}
255EXPORT_SYMBOL_GPL(nfs_file_fsync);
256
257/*
258 * Decide whether a read/modify/write cycle may be more efficient
259 * then a modify/write/read cycle when writing to a page in the
260 * page cache.
261 *
262 * Some pNFS layout drivers can only read/write at a certain block
263 * granularity like all block devices and therefore we must perform
264 * read/modify/write whenever a page hasn't read yet and the data
265 * to be written there is not aligned to a block boundary and/or
266 * smaller than the block size.
267 *
268 * The modify/write/read cycle may occur if a page is read before
269 * being completely filled by the writer.  In this situation, the
270 * page must be completely written to stable storage on the server
271 * before it can be refilled by reading in the page from the server.
272 * This can lead to expensive, small, FILE_SYNC mode writes being
273 * done.
274 *
275 * It may be more efficient to read the page first if the file is
276 * open for reading in addition to writing, the page is not marked
277 * as Uptodate, it is not dirty or waiting to be committed,
278 * indicating that it was previously allocated and then modified,
279 * that there were valid bytes of data in that range of the file,
280 * and that the new data won't completely replace the old data in
281 * that range of the file.
282 */
283static bool nfs_full_page_write(struct page *page, loff_t pos, unsigned int len)
284{
285	unsigned int pglen = nfs_page_length(page);
286	unsigned int offset = pos & (PAGE_SIZE - 1);
287	unsigned int end = offset + len;
288
289	return !pglen || (end >= pglen && !offset);
290}
291
292static bool nfs_want_read_modify_write(struct file *file, struct page *page,
293			loff_t pos, unsigned int len)
294{
295	/*
296	 * Up-to-date pages, those with ongoing or full-page write
297	 * don't need read/modify/write
298	 */
299	if (PageUptodate(page) || PagePrivate(page) ||
300	    nfs_full_page_write(page, pos, len))
301		return false;
302
303	if (pnfs_ld_read_whole_page(file->f_mapping->host))
304		return true;
305	/* Open for reading too? */
306	if (file->f_mode & FMODE_READ)
307		return true;
308	return false;
309}
310
311/*
312 * This does the "real" work of the write. We must allocate and lock the
313 * page to be sent back to the generic routine, which then copies the
314 * data from user space.
315 *
316 * If the writer ends up delaying the write, the writer needs to
317 * increment the page use counts until he is done with the page.
318 */
319static int nfs_write_begin(struct file *file, struct address_space *mapping,
320			loff_t pos, unsigned len, unsigned flags,
321			struct page **pagep, void **fsdata)
322{
323	int ret;
324	pgoff_t index = pos >> PAGE_SHIFT;
325	struct page *page;
326	int once_thru = 0;
327
328	dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
329		file, mapping->host->i_ino, len, (long long) pos);
330
331start:
332	page = grab_cache_page_write_begin(mapping, index, flags);
333	if (!page)
334		return -ENOMEM;
335	*pagep = page;
336
337	ret = nfs_flush_incompatible(file, page);
338	if (ret) {
339		unlock_page(page);
340		put_page(page);
341	} else if (!once_thru &&
342		   nfs_want_read_modify_write(file, page, pos, len)) {
343		once_thru = 1;
344		ret = nfs_readpage(file, page);
345		put_page(page);
346		if (!ret)
347			goto start;
348	}
349	return ret;
350}
351
352static int nfs_write_end(struct file *file, struct address_space *mapping,
353			loff_t pos, unsigned len, unsigned copied,
354			struct page *page, void *fsdata)
355{
356	unsigned offset = pos & (PAGE_SIZE - 1);
357	struct nfs_open_context *ctx = nfs_file_open_context(file);
358	int status;
359
360	dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
361		file, mapping->host->i_ino, len, (long long) pos);
362
363	/*
364	 * Zero any uninitialised parts of the page, and then mark the page
365	 * as up to date if it turns out that we're extending the file.
366	 */
367	if (!PageUptodate(page)) {
368		unsigned pglen = nfs_page_length(page);
369		unsigned end = offset + copied;
370
371		if (pglen == 0) {
372			zero_user_segments(page, 0, offset,
373					end, PAGE_SIZE);
374			SetPageUptodate(page);
375		} else if (end >= pglen) {
376			zero_user_segment(page, end, PAGE_SIZE);
377			if (offset == 0)
378				SetPageUptodate(page);
379		} else
380			zero_user_segment(page, pglen, PAGE_SIZE);
381	}
382
383	status = nfs_updatepage(file, page, offset, copied);
384
385	unlock_page(page);
386	put_page(page);
387
388	if (status < 0)
389		return status;
390	NFS_I(mapping->host)->write_io += copied;
391
392	if (nfs_ctx_key_to_expire(ctx, mapping->host)) {
393		status = nfs_wb_all(mapping->host);
394		if (status < 0)
395			return status;
396	}
397
398	return copied;
399}
400
401/*
402 * Partially or wholly invalidate a page
403 * - Release the private state associated with a page if undergoing complete
404 *   page invalidation
405 * - Called if either PG_private or PG_fscache is set on the page
406 * - Caller holds page lock
407 */
408static void nfs_invalidate_page(struct page *page, unsigned int offset,
409				unsigned int length)
410{
411	dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %u, %u)\n",
412		 page, offset, length);
413
414	if (offset != 0 || length < PAGE_SIZE)
415		return;
416	/* Cancel any unstarted writes on this page */
417	nfs_wb_page_cancel(page_file_mapping(page)->host, page);
418
419	nfs_fscache_invalidate_page(page, page->mapping->host);
420}
421
422/*
423 * Attempt to release the private state associated with a page
424 * - Called if either PG_private or PG_fscache is set on the page
425 * - Caller holds page lock
426 * - Return true (may release page) or false (may not)
427 */
428static int nfs_release_page(struct page *page, gfp_t gfp)
429{
430	dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
431
432	/* If PagePrivate() is set, then the page is not freeable */
433	if (PagePrivate(page))
434		return 0;
435	return nfs_fscache_release_page(page, gfp);
436}
437
438static void nfs_check_dirty_writeback(struct page *page,
439				bool *dirty, bool *writeback)
440{
441	struct nfs_inode *nfsi;
442	struct address_space *mapping = page_file_mapping(page);
443
444	if (!mapping || PageSwapCache(page))
445		return;
446
447	/*
448	 * Check if an unstable page is currently being committed and
449	 * if so, have the VM treat it as if the page is under writeback
450	 * so it will not block due to pages that will shortly be freeable.
451	 */
452	nfsi = NFS_I(mapping->host);
453	if (atomic_read(&nfsi->commit_info.rpcs_out)) {
454		*writeback = true;
455		return;
456	}
457
458	/*
459	 * If PagePrivate() is set, then the page is not freeable and as the
460	 * inode is not being committed, it's not going to be cleaned in the
461	 * near future so treat it as dirty
462	 */
463	if (PagePrivate(page))
464		*dirty = true;
465}
466
467/*
468 * Attempt to clear the private state associated with a page when an error
469 * occurs that requires the cached contents of an inode to be written back or
470 * destroyed
471 * - Called if either PG_private or fscache is set on the page
472 * - Caller holds page lock
473 * - Return 0 if successful, -error otherwise
474 */
475static int nfs_launder_page(struct page *page)
476{
477	struct inode *inode = page_file_mapping(page)->host;
478	struct nfs_inode *nfsi = NFS_I(inode);
479
480	dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
481		inode->i_ino, (long long)page_offset(page));
482
483	nfs_fscache_wait_on_page_write(nfsi, page);
484	return nfs_wb_page(inode, page);
485}
486
487static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
488						sector_t *span)
489{
490	unsigned long blocks;
491	long long isize;
492	struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
493	struct inode *inode = file->f_mapping->host;
494
495	spin_lock(&inode->i_lock);
496	blocks = inode->i_blocks;
497	isize = inode->i_size;
498	spin_unlock(&inode->i_lock);
499	if (blocks*512 < isize) {
500		pr_warn("swap activate: swapfile has holes\n");
501		return -EINVAL;
502	}
503
504	*span = sis->pages;
505
506	return rpc_clnt_swap_activate(clnt);
507}
508
509static void nfs_swap_deactivate(struct file *file)
510{
511	struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
512
513	rpc_clnt_swap_deactivate(clnt);
514}
515
516const struct address_space_operations nfs_file_aops = {
517	.readpage = nfs_readpage,
518	.readpages = nfs_readpages,
519	.set_page_dirty = __set_page_dirty_nobuffers,
520	.writepage = nfs_writepage,
521	.writepages = nfs_writepages,
522	.write_begin = nfs_write_begin,
523	.write_end = nfs_write_end,
524	.invalidatepage = nfs_invalidate_page,
525	.releasepage = nfs_release_page,
526	.direct_IO = nfs_direct_IO,
527#ifdef CONFIG_MIGRATION
528	.migratepage = nfs_migrate_page,
529#endif
530	.launder_page = nfs_launder_page,
531	.is_dirty_writeback = nfs_check_dirty_writeback,
532	.error_remove_page = generic_error_remove_page,
533	.swap_activate = nfs_swap_activate,
534	.swap_deactivate = nfs_swap_deactivate,
535};
536
537/*
538 * Notification that a PTE pointing to an NFS page is about to be made
539 * writable, implying that someone is about to modify the page through a
540 * shared-writable mapping
541 */
542static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf)
543{
544	struct page *page = vmf->page;
545	struct file *filp = vmf->vma->vm_file;
546	struct inode *inode = file_inode(filp);
547	unsigned pagelen;
548	vm_fault_t ret = VM_FAULT_NOPAGE;
549	struct address_space *mapping;
550
551	dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
552		filp, filp->f_mapping->host->i_ino,
553		(long long)page_offset(page));
554
555	sb_start_pagefault(inode->i_sb);
556
557	/* make sure the cache has finished storing the page */
558	nfs_fscache_wait_on_page_write(NFS_I(inode), page);
559
560	wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
561			nfs_wait_bit_killable, TASK_KILLABLE);
562
563	lock_page(page);
564	mapping = page_file_mapping(page);
565	if (mapping != inode->i_mapping)
566		goto out_unlock;
567
568	wait_on_page_writeback(page);
569
570	pagelen = nfs_page_length(page);
571	if (pagelen == 0)
572		goto out_unlock;
573
574	ret = VM_FAULT_LOCKED;
575	if (nfs_flush_incompatible(filp, page) == 0 &&
576	    nfs_updatepage(filp, page, 0, pagelen) == 0)
577		goto out;
578
579	ret = VM_FAULT_SIGBUS;
580out_unlock:
581	unlock_page(page);
582out:
583	sb_end_pagefault(inode->i_sb);
584	return ret;
585}
586
587static const struct vm_operations_struct nfs_file_vm_ops = {
588	.fault = filemap_fault,
589	.map_pages = filemap_map_pages,
590	.page_mkwrite = nfs_vm_page_mkwrite,
591};
592
593static int nfs_need_check_write(struct file *filp, struct inode *inode,
594				int error)
595{
596	struct nfs_open_context *ctx;
597
598	ctx = nfs_file_open_context(filp);
599	if (nfs_error_is_fatal_on_server(error) ||
600	    nfs_ctx_key_to_expire(ctx, inode))
601		return 1;
602	return 0;
603}
604
605ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
606{
607	struct file *file = iocb->ki_filp;
608	struct inode *inode = file_inode(file);
609	unsigned int mntflags = NFS_SERVER(inode)->flags;
610	ssize_t result, written;
611	errseq_t since;
612	int error;
613
614	result = nfs_key_timeout_notify(file, inode);
615	if (result)
616		return result;
617
618	if (iocb->ki_flags & IOCB_DIRECT)
619		return nfs_file_direct_write(iocb, from);
620
621	dprintk("NFS: write(%pD2, %zu@%Ld)\n",
622		file, iov_iter_count(from), (long long) iocb->ki_pos);
623
624	if (IS_SWAPFILE(inode))
625		goto out_swapfile;
626	/*
627	 * O_APPEND implies that we must revalidate the file length.
628	 */
629	if (iocb->ki_flags & IOCB_APPEND || iocb->ki_pos > i_size_read(inode)) {
630		result = nfs_revalidate_file_size(inode, file);
631		if (result)
632			goto out;
633	}
634
635	nfs_clear_invalid_mapping(file->f_mapping);
636
637	since = filemap_sample_wb_err(file->f_mapping);
638	nfs_start_io_write(inode);
639	result = generic_write_checks(iocb, from);
640	if (result > 0) {
641		current->backing_dev_info = inode_to_bdi(inode);
642		result = generic_perform_write(file, from, iocb->ki_pos);
643		current->backing_dev_info = NULL;
644	}
645	nfs_end_io_write(inode);
646	if (result <= 0)
647		goto out;
648
649	written = result;
650	iocb->ki_pos += written;
651
652	if (mntflags & NFS_MOUNT_WRITE_EAGER) {
653		result = filemap_fdatawrite_range(file->f_mapping,
654						  iocb->ki_pos - written,
655						  iocb->ki_pos - 1);
656		if (result < 0)
657			goto out;
658	}
659	if (mntflags & NFS_MOUNT_WRITE_WAIT) {
660		result = filemap_fdatawait_range(file->f_mapping,
661						 iocb->ki_pos - written,
662						 iocb->ki_pos - 1);
663		if (result < 0)
664			goto out;
665	}
666	result = generic_write_sync(iocb, written);
667	if (result < 0)
668		goto out;
669
670	/* Return error values */
671	error = filemap_check_wb_err(file->f_mapping, since);
672	if (nfs_need_check_write(file, inode, error)) {
673		int err = nfs_wb_all(inode);
674		if (err < 0)
675			result = err;
676	}
677	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
678out:
679	return result;
680
681out_swapfile:
682	printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
683	return -ETXTBSY;
684}
685EXPORT_SYMBOL_GPL(nfs_file_write);
686
687static int
688do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
689{
690	struct inode *inode = filp->f_mapping->host;
691	int status = 0;
692	unsigned int saved_type = fl->fl_type;
693
694	/* Try local locking first */
695	posix_test_lock(filp, fl);
696	if (fl->fl_type != F_UNLCK) {
697		/* found a conflict */
698		goto out;
699	}
700	fl->fl_type = saved_type;
701
702	if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
703		goto out_noconflict;
704
705	if (is_local)
706		goto out_noconflict;
707
708	status = NFS_PROTO(inode)->lock(filp, cmd, fl);
709out:
710	return status;
711out_noconflict:
712	fl->fl_type = F_UNLCK;
713	goto out;
714}
715
716static int
717do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
718{
719	struct inode *inode = filp->f_mapping->host;
720	struct nfs_lock_context *l_ctx;
721	int status;
722
723	/*
724	 * Flush all pending writes before doing anything
725	 * with locks..
726	 */
727	nfs_wb_all(inode);
728
729	l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
730	if (!IS_ERR(l_ctx)) {
731		status = nfs_iocounter_wait(l_ctx);
732		nfs_put_lock_context(l_ctx);
733		/*  NOTE: special case
734		 * 	If we're signalled while cleaning up locks on process exit, we
735		 * 	still need to complete the unlock.
736		 */
737		if (status < 0 && !(fl->fl_flags & FL_CLOSE))
738			return status;
739	}
740
741	/*
742	 * Use local locking if mounted with "-onolock" or with appropriate
743	 * "-olocal_lock="
744	 */
745	if (!is_local)
746		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
747	else
748		status = locks_lock_file_wait(filp, fl);
749	return status;
750}
751
752static int
753do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
754{
755	struct inode *inode = filp->f_mapping->host;
756	int status;
757
758	/*
759	 * Flush all pending writes before doing anything
760	 * with locks..
761	 */
762	status = nfs_sync_mapping(filp->f_mapping);
763	if (status != 0)
764		goto out;
765
766	/*
767	 * Use local locking if mounted with "-onolock" or with appropriate
768	 * "-olocal_lock="
769	 */
770	if (!is_local)
771		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
772	else
773		status = locks_lock_file_wait(filp, fl);
774	if (status < 0)
775		goto out;
776
777	/*
778	 * Invalidate cache to prevent missing any changes.  If
779	 * the file is mapped, clear the page cache as well so
780	 * those mappings will be loaded.
781	 *
782	 * This makes locking act as a cache coherency point.
783	 */
784	nfs_sync_mapping(filp->f_mapping);
785	if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) {
786		nfs_zap_caches(inode);
787		if (mapping_mapped(filp->f_mapping))
788			nfs_revalidate_mapping(inode, filp->f_mapping);
789	}
790out:
791	return status;
792}
793
794/*
795 * Lock a (portion of) a file
796 */
797int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
798{
799	struct inode *inode = filp->f_mapping->host;
800	int ret = -ENOLCK;
801	int is_local = 0;
802
803	dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n",
804			filp, fl->fl_type, fl->fl_flags,
805			(long long)fl->fl_start, (long long)fl->fl_end);
806
807	nfs_inc_stats(inode, NFSIOS_VFSLOCK);
808
809	if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
810		is_local = 1;
811
812	if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
813		ret = NFS_PROTO(inode)->lock_check_bounds(fl);
814		if (ret < 0)
815			goto out_err;
816	}
817
818	if (IS_GETLK(cmd))
819		ret = do_getlk(filp, cmd, fl, is_local);
820	else if (fl->fl_type == F_UNLCK)
821		ret = do_unlk(filp, cmd, fl, is_local);
822	else
823		ret = do_setlk(filp, cmd, fl, is_local);
824out_err:
825	return ret;
826}
827EXPORT_SYMBOL_GPL(nfs_lock);
828
829/*
830 * Lock a (portion of) a file
831 */
832int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
833{
834	struct inode *inode = filp->f_mapping->host;
835	int is_local = 0;
836
837	dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n",
838			filp, fl->fl_type, fl->fl_flags);
839
840	if (!(fl->fl_flags & FL_FLOCK))
841		return -ENOLCK;
842
843	/*
844	 * The NFSv4 protocol doesn't support LOCK_MAND, which is not part of
845	 * any standard. In principle we might be able to support LOCK_MAND
846	 * on NFSv2/3 since NLMv3/4 support DOS share modes, but for now the
847	 * NFS code is not set up for it.
848	 */
849	if (fl->fl_type & LOCK_MAND)
850		return -EINVAL;
851
852	if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
853		is_local = 1;
854
855	/* We're simulating flock() locks using posix locks on the server */
856	if (fl->fl_type == F_UNLCK)
857		return do_unlk(filp, cmd, fl, is_local);
858	return do_setlk(filp, cmd, fl, is_local);
859}
860EXPORT_SYMBOL_GPL(nfs_flock);
861
862const struct file_operations nfs_file_operations = {
863	.llseek		= nfs_file_llseek,
864	.read_iter	= nfs_file_read,
865	.write_iter	= nfs_file_write,
866	.mmap		= nfs_file_mmap,
867	.open		= nfs_file_open,
868	.flush		= nfs_file_flush,
869	.release	= nfs_file_release,
870	.fsync		= nfs_file_fsync,
871	.lock		= nfs_lock,
872	.flock		= nfs_flock,
873	.splice_read	= generic_file_splice_read,
874	.splice_write	= iter_file_splice_write,
875	.check_flags	= nfs_check_flags,
876	.setlease	= simple_nosetlease,
877};
878EXPORT_SYMBOL_GPL(nfs_file_operations);
879