xref: /linux/fs/nfs/file.c (revision 1110ce6a1e34fe1fdc1bfe4ad52405f327d5083b)
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 #include <linux/compaction.h>
33 
34 #include <linux/uaccess.h>
35 #include <linux/filelock.h>
36 
37 #include "delegation.h"
38 #include "internal.h"
39 #include "iostat.h"
40 #include "fscache.h"
41 #include "pnfs.h"
42 
43 #include "nfstrace.h"
44 
45 #define NFSDBG_FACILITY		NFSDBG_FILE
46 
47 static const struct vm_operations_struct nfs_file_vm_ops;
48 
nfs_check_flags(int flags)49 int nfs_check_flags(int flags)
50 {
51 	if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
52 		return -EINVAL;
53 
54 	return 0;
55 }
56 EXPORT_SYMBOL_GPL(nfs_check_flags);
57 
58 /*
59  * Open file
60  */
61 static int
nfs_file_open(struct inode * inode,struct file * filp)62 nfs_file_open(struct inode *inode, struct file *filp)
63 {
64 	int res;
65 
66 	dprintk("NFS: open file(%pD2)\n", filp);
67 
68 	nfs_inc_stats(inode, NFSIOS_VFSOPEN);
69 	res = nfs_check_flags(filp->f_flags);
70 	if (res)
71 		return res;
72 
73 	res = nfs_open(inode, filp);
74 	if (res == 0)
75 		filp->f_mode |= FMODE_CAN_ODIRECT;
76 	return res;
77 }
78 
79 int
nfs_file_release(struct inode * inode,struct file * filp)80 nfs_file_release(struct inode *inode, struct file *filp)
81 {
82 	dprintk("NFS: release(%pD2)\n", filp);
83 
84 	nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
85 	nfs_file_clear_open_context(filp);
86 	nfs_fscache_release_file(inode, filp);
87 	return 0;
88 }
89 EXPORT_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  */
nfs_revalidate_file_size(struct inode * inode,struct file * filp)102 static 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;
111 force_reval:
112 	return __nfs_revalidate_inode(server, inode);
113 }
114 
nfs_file_llseek(struct file * filp,loff_t offset,int whence)115 loff_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 }
134 EXPORT_SYMBOL_GPL(nfs_file_llseek);
135 
136 /*
137  * Flush all dirty pages, and check for write errors.
138  */
139 static int
nfs_file_flush(struct file * file,fl_owner_t id)140 nfs_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 
157 ssize_t
nfs_file_read(struct kiocb * iocb,struct iov_iter * to)158 nfs_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, false);
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 	result = nfs_start_io_read(inode);
171 	if (result)
172 		return result;
173 
174 	result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
175 	if (!result) {
176 		result = generic_file_read_iter(iocb, to);
177 		if (result > 0)
178 			nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
179 	}
180 	nfs_end_io_read(inode);
181 	return result;
182 }
183 EXPORT_SYMBOL_GPL(nfs_file_read);
184 
185 ssize_t
nfs_file_splice_read(struct file * in,loff_t * ppos,struct pipe_inode_info * pipe,size_t len,unsigned int flags)186 nfs_file_splice_read(struct file *in, loff_t *ppos, struct pipe_inode_info *pipe,
187 		     size_t len, unsigned int flags)
188 {
189 	struct inode *inode = file_inode(in);
190 	ssize_t result;
191 
192 	dprintk("NFS: splice_read(%pD2, %zu@%llu)\n", in, len, *ppos);
193 
194 	result = nfs_start_io_read(inode);
195 	if (result)
196 		return result;
197 
198 	result = nfs_revalidate_mapping(inode, in->f_mapping);
199 	if (!result) {
200 		result = filemap_splice_read(in, ppos, pipe, len, flags);
201 		if (result > 0)
202 			nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
203 	}
204 	nfs_end_io_read(inode);
205 	return result;
206 }
207 EXPORT_SYMBOL_GPL(nfs_file_splice_read);
208 
209 int
nfs_file_mmap(struct file * file,struct vm_area_struct * vma)210 nfs_file_mmap(struct file *file, struct vm_area_struct *vma)
211 {
212 	struct inode *inode = file_inode(file);
213 	int	status;
214 
215 	dprintk("NFS: mmap(%pD2)\n", file);
216 
217 	/* Note: generic_file_mmap() returns ENOSYS on nommu systems
218 	 *       so we call that before revalidating the mapping
219 	 */
220 	status = generic_file_mmap(file, vma);
221 	if (!status) {
222 		vma->vm_ops = &nfs_file_vm_ops;
223 		status = nfs_revalidate_mapping(inode, file->f_mapping);
224 	}
225 	return status;
226 }
227 EXPORT_SYMBOL_GPL(nfs_file_mmap);
228 
229 /*
230  * Flush any dirty pages for this process, and check for write errors.
231  * The return status from this call provides a reliable indication of
232  * whether any write errors occurred for this process.
233  */
234 static int
nfs_file_fsync_commit(struct file * file,int datasync)235 nfs_file_fsync_commit(struct file *file, int datasync)
236 {
237 	struct inode *inode = file_inode(file);
238 	int ret, ret2;
239 
240 	dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
241 
242 	nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
243 	ret = nfs_commit_inode(inode, FLUSH_SYNC);
244 	ret2 = file_check_and_advance_wb_err(file);
245 	if (ret2 < 0)
246 		return ret2;
247 	return ret;
248 }
249 
250 int
nfs_file_fsync(struct file * file,loff_t start,loff_t end,int datasync)251 nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
252 {
253 	struct inode *inode = file_inode(file);
254 	struct nfs_inode *nfsi = NFS_I(inode);
255 	long save_nredirtied = atomic_long_read(&nfsi->redirtied_pages);
256 	long nredirtied;
257 	int ret;
258 
259 	trace_nfs_fsync_enter(inode);
260 
261 	for (;;) {
262 		ret = file_write_and_wait_range(file, start, end);
263 		if (ret != 0)
264 			break;
265 		ret = nfs_file_fsync_commit(file, datasync);
266 		if (ret != 0)
267 			break;
268 		ret = pnfs_sync_inode(inode, !!datasync);
269 		if (ret != 0)
270 			break;
271 		nredirtied = atomic_long_read(&nfsi->redirtied_pages);
272 		if (nredirtied == save_nredirtied)
273 			break;
274 		save_nredirtied = nredirtied;
275 	}
276 
277 	trace_nfs_fsync_exit(inode, ret);
278 	return ret;
279 }
280 EXPORT_SYMBOL_GPL(nfs_file_fsync);
281 
282 /*
283  * Decide whether a read/modify/write cycle may be more efficient
284  * then a modify/write/read cycle when writing to a page in the
285  * page cache.
286  *
287  * Some pNFS layout drivers can only read/write at a certain block
288  * granularity like all block devices and therefore we must perform
289  * read/modify/write whenever a page hasn't read yet and the data
290  * to be written there is not aligned to a block boundary and/or
291  * smaller than the block size.
292  *
293  * The modify/write/read cycle may occur if a page is read before
294  * being completely filled by the writer.  In this situation, the
295  * page must be completely written to stable storage on the server
296  * before it can be refilled by reading in the page from the server.
297  * This can lead to expensive, small, FILE_SYNC mode writes being
298  * done.
299  *
300  * It may be more efficient to read the page first if the file is
301  * open for reading in addition to writing, the page is not marked
302  * as Uptodate, it is not dirty or waiting to be committed,
303  * indicating that it was previously allocated and then modified,
304  * that there were valid bytes of data in that range of the file,
305  * and that the new data won't completely replace the old data in
306  * that range of the file.
307  */
nfs_folio_is_full_write(struct folio * folio,loff_t pos,unsigned int len)308 static bool nfs_folio_is_full_write(struct folio *folio, loff_t pos,
309 				    unsigned int len)
310 {
311 	unsigned int pglen = nfs_folio_length(folio);
312 	unsigned int offset = offset_in_folio(folio, pos);
313 	unsigned int end = offset + len;
314 
315 	return !pglen || (end >= pglen && !offset);
316 }
317 
nfs_want_read_modify_write(struct file * file,struct folio * folio,loff_t pos,unsigned int len)318 static bool nfs_want_read_modify_write(struct file *file, struct folio *folio,
319 				       loff_t pos, unsigned int len)
320 {
321 	/*
322 	 * Up-to-date pages, those with ongoing or full-page write
323 	 * don't need read/modify/write
324 	 */
325 	if (folio_test_uptodate(folio) || folio_test_private(folio) ||
326 	    nfs_folio_is_full_write(folio, pos, len))
327 		return false;
328 
329 	if (pnfs_ld_read_whole_page(file_inode(file)))
330 		return true;
331 	/* Open for reading too? */
332 	if (file->f_mode & FMODE_READ)
333 		return true;
334 	return false;
335 }
336 
337 /*
338  * This does the "real" work of the write. We must allocate and lock the
339  * page to be sent back to the generic routine, which then copies the
340  * data from user space.
341  *
342  * If the writer ends up delaying the write, the writer needs to
343  * increment the page use counts until he is done with the page.
344  */
nfs_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct folio ** foliop,void ** fsdata)345 static int nfs_write_begin(struct file *file, struct address_space *mapping,
346 			   loff_t pos, unsigned len, struct folio **foliop,
347 			   void **fsdata)
348 {
349 	fgf_t fgp = FGP_WRITEBEGIN;
350 	struct folio *folio;
351 	int once_thru = 0;
352 	int ret;
353 
354 	dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
355 		file, mapping->host->i_ino, len, (long long) pos);
356 
357 	fgp |= fgf_set_order(len);
358 start:
359 	folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, fgp,
360 				    mapping_gfp_mask(mapping));
361 	if (IS_ERR(folio))
362 		return PTR_ERR(folio);
363 	*foliop = folio;
364 
365 	ret = nfs_flush_incompatible(file, folio);
366 	if (ret) {
367 		folio_unlock(folio);
368 		folio_put(folio);
369 	} else if (!once_thru &&
370 		   nfs_want_read_modify_write(file, folio, pos, len)) {
371 		once_thru = 1;
372 		ret = nfs_read_folio(file, folio);
373 		folio_put(folio);
374 		if (!ret)
375 			goto start;
376 	}
377 	return ret;
378 }
379 
nfs_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)380 static int nfs_write_end(struct file *file, struct address_space *mapping,
381 			 loff_t pos, unsigned len, unsigned copied,
382 			 struct folio *folio, void *fsdata)
383 {
384 	struct nfs_open_context *ctx = nfs_file_open_context(file);
385 	unsigned offset = offset_in_folio(folio, pos);
386 	int status;
387 
388 	dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
389 		file, mapping->host->i_ino, len, (long long) pos);
390 
391 	/*
392 	 * Zero any uninitialised parts of the page, and then mark the page
393 	 * as up to date if it turns out that we're extending the file.
394 	 */
395 	if (!folio_test_uptodate(folio)) {
396 		size_t fsize = folio_size(folio);
397 		unsigned pglen = nfs_folio_length(folio);
398 		unsigned end = offset + copied;
399 
400 		if (pglen == 0) {
401 			folio_zero_segments(folio, 0, offset, end, fsize);
402 			folio_mark_uptodate(folio);
403 		} else if (end >= pglen) {
404 			folio_zero_segment(folio, end, fsize);
405 			if (offset == 0)
406 				folio_mark_uptodate(folio);
407 		} else
408 			folio_zero_segment(folio, pglen, fsize);
409 	}
410 
411 	status = nfs_update_folio(file, folio, offset, copied);
412 
413 	folio_unlock(folio);
414 	folio_put(folio);
415 
416 	if (status < 0)
417 		return status;
418 	NFS_I(mapping->host)->write_io += copied;
419 
420 	if (nfs_ctx_key_to_expire(ctx, mapping->host))
421 		nfs_wb_all(mapping->host);
422 
423 	return copied;
424 }
425 
426 /*
427  * Partially or wholly invalidate a page
428  * - Release the private state associated with a page if undergoing complete
429  *   page invalidation
430  * - Called if either PG_private or PG_fscache is set on the page
431  * - Caller holds page lock
432  */
nfs_invalidate_folio(struct folio * folio,size_t offset,size_t length)433 static void nfs_invalidate_folio(struct folio *folio, size_t offset,
434 				size_t length)
435 {
436 	struct inode *inode = folio->mapping->host;
437 	dfprintk(PAGECACHE, "NFS: invalidate_folio(%lu, %zu, %zu)\n",
438 		 folio->index, offset, length);
439 
440 	if (offset != 0 || length < folio_size(folio))
441 		return;
442 	/* Cancel any unstarted writes on this page */
443 	nfs_wb_folio_cancel(inode, folio);
444 	folio_wait_private_2(folio); /* [DEPRECATED] */
445 	trace_nfs_invalidate_folio(inode, folio_pos(folio) + offset, length);
446 }
447 
448 /*
449  * Attempt to release the private state associated with a folio
450  * - Called if either private or fscache flags are set on the folio
451  * - Caller holds folio lock
452  * - Return true (may release folio) or false (may not)
453  */
nfs_release_folio(struct folio * folio,gfp_t gfp)454 static bool nfs_release_folio(struct folio *folio, gfp_t gfp)
455 {
456 	dfprintk(PAGECACHE, "NFS: release_folio(%p)\n", folio);
457 
458 	/* If the private flag is set, then the folio is not freeable */
459 	if (folio_test_private(folio)) {
460 		if ((current_gfp_context(gfp) & GFP_KERNEL) != GFP_KERNEL ||
461 		    current_is_kswapd() || current_is_kcompactd())
462 			return false;
463 		if (nfs_wb_folio(folio->mapping->host, folio) < 0)
464 			return false;
465 	}
466 	return nfs_fscache_release_folio(folio, gfp);
467 }
468 
nfs_check_dirty_writeback(struct folio * folio,bool * dirty,bool * writeback)469 static void nfs_check_dirty_writeback(struct folio *folio,
470 				bool *dirty, bool *writeback)
471 {
472 	struct nfs_inode *nfsi;
473 	struct address_space *mapping = folio->mapping;
474 
475 	/*
476 	 * Check if an unstable folio is currently being committed and
477 	 * if so, have the VM treat it as if the folio is under writeback
478 	 * so it will not block due to folios that will shortly be freeable.
479 	 */
480 	nfsi = NFS_I(mapping->host);
481 	if (atomic_read(&nfsi->commit_info.rpcs_out)) {
482 		*writeback = true;
483 		return;
484 	}
485 
486 	/*
487 	 * If the private flag is set, then the folio is not freeable
488 	 * and as the inode is not being committed, it's not going to
489 	 * be cleaned in the near future so treat it as dirty
490 	 */
491 	if (folio_test_private(folio))
492 		*dirty = true;
493 }
494 
495 /*
496  * Attempt to clear the private state associated with a page when an error
497  * occurs that requires the cached contents of an inode to be written back or
498  * destroyed
499  * - Called if either PG_private or fscache is set on the page
500  * - Caller holds page lock
501  * - Return 0 if successful, -error otherwise
502  */
nfs_launder_folio(struct folio * folio)503 static int nfs_launder_folio(struct folio *folio)
504 {
505 	struct inode *inode = folio->mapping->host;
506 	int ret;
507 
508 	dfprintk(PAGECACHE, "NFS: launder_folio(%ld, %llu)\n",
509 		inode->i_ino, folio_pos(folio));
510 
511 	folio_wait_private_2(folio); /* [DEPRECATED] */
512 	ret = nfs_wb_folio(inode, folio);
513 	trace_nfs_launder_folio_done(inode, folio_pos(folio),
514 			folio_size(folio), ret);
515 	return ret;
516 }
517 
nfs_swap_activate(struct swap_info_struct * sis,struct file * file,sector_t * span)518 static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
519 						sector_t *span)
520 {
521 	unsigned long blocks;
522 	long long isize;
523 	int ret;
524 	struct inode *inode = file_inode(file);
525 	struct rpc_clnt *clnt = NFS_CLIENT(inode);
526 	struct nfs_client *cl = NFS_SERVER(inode)->nfs_client;
527 
528 	spin_lock(&inode->i_lock);
529 	blocks = inode->i_blocks;
530 	isize = inode->i_size;
531 	spin_unlock(&inode->i_lock);
532 	if (blocks*512 < isize) {
533 		pr_warn("swap activate: swapfile has holes\n");
534 		return -EINVAL;
535 	}
536 
537 	ret = rpc_clnt_swap_activate(clnt);
538 	if (ret)
539 		return ret;
540 	ret = add_swap_extent(sis, 0, sis->max, 0);
541 	if (ret < 0) {
542 		rpc_clnt_swap_deactivate(clnt);
543 		return ret;
544 	}
545 
546 	*span = sis->pages;
547 
548 	if (cl->rpc_ops->enable_swap)
549 		cl->rpc_ops->enable_swap(inode);
550 
551 	sis->flags |= SWP_FS_OPS;
552 	return ret;
553 }
554 
nfs_swap_deactivate(struct file * file)555 static void nfs_swap_deactivate(struct file *file)
556 {
557 	struct inode *inode = file_inode(file);
558 	struct rpc_clnt *clnt = NFS_CLIENT(inode);
559 	struct nfs_client *cl = NFS_SERVER(inode)->nfs_client;
560 
561 	rpc_clnt_swap_deactivate(clnt);
562 	if (cl->rpc_ops->disable_swap)
563 		cl->rpc_ops->disable_swap(file_inode(file));
564 }
565 
566 const struct address_space_operations nfs_file_aops = {
567 	.read_folio = nfs_read_folio,
568 	.readahead = nfs_readahead,
569 	.dirty_folio = filemap_dirty_folio,
570 	.writepages = nfs_writepages,
571 	.write_begin = nfs_write_begin,
572 	.write_end = nfs_write_end,
573 	.invalidate_folio = nfs_invalidate_folio,
574 	.release_folio = nfs_release_folio,
575 	.migrate_folio = nfs_migrate_folio,
576 	.launder_folio = nfs_launder_folio,
577 	.is_dirty_writeback = nfs_check_dirty_writeback,
578 	.error_remove_folio = generic_error_remove_folio,
579 	.swap_activate = nfs_swap_activate,
580 	.swap_deactivate = nfs_swap_deactivate,
581 	.swap_rw = nfs_swap_rw,
582 };
583 
584 /*
585  * Notification that a PTE pointing to an NFS page is about to be made
586  * writable, implying that someone is about to modify the page through a
587  * shared-writable mapping
588  */
nfs_vm_page_mkwrite(struct vm_fault * vmf)589 static vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf)
590 {
591 	struct file *filp = vmf->vma->vm_file;
592 	struct inode *inode = file_inode(filp);
593 	unsigned pagelen;
594 	vm_fault_t ret = VM_FAULT_NOPAGE;
595 	struct address_space *mapping;
596 	struct folio *folio = page_folio(vmf->page);
597 
598 	dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
599 		 filp, filp->f_mapping->host->i_ino,
600 		 (long long)folio_pos(folio));
601 
602 	sb_start_pagefault(inode->i_sb);
603 
604 	/* make sure the cache has finished storing the page */
605 	if (folio_test_private_2(folio) && /* [DEPRECATED] */
606 	    folio_wait_private_2_killable(folio) < 0) {
607 		ret = VM_FAULT_RETRY;
608 		goto out;
609 	}
610 
611 	wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
612 			   nfs_wait_bit_killable,
613 			   TASK_KILLABLE|TASK_FREEZABLE_UNSAFE);
614 
615 	folio_lock(folio);
616 	mapping = folio->mapping;
617 	if (mapping != inode->i_mapping)
618 		goto out_unlock;
619 
620 	folio_wait_writeback(folio);
621 
622 	pagelen = nfs_folio_length(folio);
623 	if (pagelen == 0)
624 		goto out_unlock;
625 
626 	ret = VM_FAULT_LOCKED;
627 	if (nfs_flush_incompatible(filp, folio) == 0 &&
628 	    nfs_update_folio(filp, folio, 0, pagelen) == 0)
629 		goto out;
630 
631 	ret = VM_FAULT_SIGBUS;
632 out_unlock:
633 	folio_unlock(folio);
634 out:
635 	sb_end_pagefault(inode->i_sb);
636 	return ret;
637 }
638 
639 static const struct vm_operations_struct nfs_file_vm_ops = {
640 	.fault = filemap_fault,
641 	.map_pages = filemap_map_pages,
642 	.page_mkwrite = nfs_vm_page_mkwrite,
643 };
644 
nfs_file_write(struct kiocb * iocb,struct iov_iter * from)645 ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
646 {
647 	struct file *file = iocb->ki_filp;
648 	struct inode *inode = file_inode(file);
649 	unsigned int mntflags = NFS_SERVER(inode)->flags;
650 	ssize_t result, written;
651 	errseq_t since;
652 	int error;
653 
654 	result = nfs_key_timeout_notify(file, inode);
655 	if (result)
656 		return result;
657 
658 	if (iocb->ki_flags & IOCB_DIRECT)
659 		return nfs_file_direct_write(iocb, from, false);
660 
661 	dprintk("NFS: write(%pD2, %zu@%Ld)\n",
662 		file, iov_iter_count(from), (long long) iocb->ki_pos);
663 
664 	if (IS_SWAPFILE(inode))
665 		goto out_swapfile;
666 	/*
667 	 * O_APPEND implies that we must revalidate the file length.
668 	 */
669 	if (iocb->ki_flags & IOCB_APPEND || iocb->ki_pos > i_size_read(inode)) {
670 		result = nfs_revalidate_file_size(inode, file);
671 		if (result)
672 			return result;
673 	}
674 
675 	nfs_clear_invalid_mapping(file->f_mapping);
676 
677 	since = filemap_sample_wb_err(file->f_mapping);
678 	error = nfs_start_io_write(inode);
679 	if (error)
680 		return error;
681 	result = generic_write_checks(iocb, from);
682 	if (result > 0)
683 		result = generic_perform_write(iocb, from);
684 	nfs_end_io_write(inode);
685 	if (result <= 0)
686 		goto out;
687 
688 	written = result;
689 	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
690 
691 	if (mntflags & NFS_MOUNT_WRITE_EAGER) {
692 		result = filemap_fdatawrite_range(file->f_mapping,
693 						  iocb->ki_pos - written,
694 						  iocb->ki_pos - 1);
695 		if (result < 0)
696 			goto out;
697 	}
698 	if (mntflags & NFS_MOUNT_WRITE_WAIT) {
699 		filemap_fdatawait_range(file->f_mapping,
700 					iocb->ki_pos - written,
701 					iocb->ki_pos - 1);
702 	}
703 	result = generic_write_sync(iocb, written);
704 	if (result < 0)
705 		return result;
706 
707 out:
708 	/* Return error values */
709 	error = filemap_check_wb_err(file->f_mapping, since);
710 	switch (error) {
711 	default:
712 		break;
713 	case -EDQUOT:
714 	case -EFBIG:
715 	case -ENOSPC:
716 		nfs_wb_all(inode);
717 		error = file_check_and_advance_wb_err(file);
718 		if (error < 0)
719 			result = error;
720 	}
721 	return result;
722 
723 out_swapfile:
724 	printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
725 	return -ETXTBSY;
726 }
727 EXPORT_SYMBOL_GPL(nfs_file_write);
728 
729 static int
do_getlk(struct file * filp,int cmd,struct file_lock * fl,int is_local)730 do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
731 {
732 	struct inode *inode = filp->f_mapping->host;
733 	int status = 0;
734 	unsigned int saved_type = fl->c.flc_type;
735 
736 	/* Try local locking first */
737 	posix_test_lock(filp, fl);
738 	if (fl->c.flc_type != F_UNLCK) {
739 		/* found a conflict */
740 		goto out;
741 	}
742 	fl->c.flc_type = saved_type;
743 
744 	if (nfs_have_read_or_write_delegation(inode))
745 		goto out_noconflict;
746 
747 	if (is_local)
748 		goto out_noconflict;
749 
750 	status = NFS_PROTO(inode)->lock(filp, cmd, fl);
751 out:
752 	return status;
753 out_noconflict:
754 	fl->c.flc_type = F_UNLCK;
755 	goto out;
756 }
757 
758 static int
do_unlk(struct file * filp,int cmd,struct file_lock * fl,int is_local)759 do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
760 {
761 	struct inode *inode = filp->f_mapping->host;
762 	struct nfs_lock_context *l_ctx;
763 	int status;
764 
765 	/*
766 	 * Flush all pending writes before doing anything
767 	 * with locks..
768 	 */
769 	nfs_wb_all(inode);
770 
771 	l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
772 	if (!IS_ERR(l_ctx)) {
773 		status = nfs_iocounter_wait(l_ctx);
774 		nfs_put_lock_context(l_ctx);
775 		/*  NOTE: special case
776 		 * 	If we're signalled while cleaning up locks on process exit, we
777 		 * 	still need to complete the unlock.
778 		 */
779 		if (status < 0 && !(fl->c.flc_flags & FL_CLOSE))
780 			return status;
781 	}
782 
783 	/*
784 	 * Use local locking if mounted with "-onolock" or with appropriate
785 	 * "-olocal_lock="
786 	 */
787 	if (!is_local)
788 		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
789 	else
790 		status = locks_lock_file_wait(filp, fl);
791 	return status;
792 }
793 
794 static int
do_setlk(struct file * filp,int cmd,struct file_lock * fl,int is_local)795 do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
796 {
797 	struct inode *inode = filp->f_mapping->host;
798 	int status;
799 
800 	/*
801 	 * Flush all pending writes before doing anything
802 	 * with locks..
803 	 */
804 	status = nfs_sync_mapping(filp->f_mapping);
805 	if (status != 0)
806 		goto out;
807 
808 	/*
809 	 * Use local locking if mounted with "-onolock" or with appropriate
810 	 * "-olocal_lock="
811 	 */
812 	if (!is_local)
813 		status = NFS_PROTO(inode)->lock(filp, cmd, fl);
814 	else
815 		status = locks_lock_file_wait(filp, fl);
816 	if (status < 0)
817 		goto out;
818 
819 	/*
820 	 * Invalidate cache to prevent missing any changes.  If
821 	 * the file is mapped, clear the page cache as well so
822 	 * those mappings will be loaded.
823 	 *
824 	 * This makes locking act as a cache coherency point.
825 	 */
826 	nfs_sync_mapping(filp->f_mapping);
827 	if (!nfs_have_read_or_write_delegation(inode)) {
828 		nfs_zap_caches(inode);
829 		if (mapping_mapped(filp->f_mapping))
830 			nfs_revalidate_mapping(inode, filp->f_mapping);
831 	}
832 out:
833 	return status;
834 }
835 
836 /*
837  * Lock a (portion of) a file
838  */
nfs_lock(struct file * filp,int cmd,struct file_lock * fl)839 int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
840 {
841 	struct inode *inode = filp->f_mapping->host;
842 	int ret = -ENOLCK;
843 	int is_local = 0;
844 
845 	dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n",
846 			filp, fl->c.flc_type, fl->c.flc_flags,
847 			(long long)fl->fl_start, (long long)fl->fl_end);
848 
849 	nfs_inc_stats(inode, NFSIOS_VFSLOCK);
850 
851 	if (fl->c.flc_flags & FL_RECLAIM)
852 		return -ENOGRACE;
853 
854 	if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
855 		is_local = 1;
856 
857 	if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
858 		ret = NFS_PROTO(inode)->lock_check_bounds(fl);
859 		if (ret < 0)
860 			goto out_err;
861 	}
862 
863 	if (IS_GETLK(cmd))
864 		ret = do_getlk(filp, cmd, fl, is_local);
865 	else if (lock_is_unlock(fl))
866 		ret = do_unlk(filp, cmd, fl, is_local);
867 	else
868 		ret = do_setlk(filp, cmd, fl, is_local);
869 out_err:
870 	return ret;
871 }
872 EXPORT_SYMBOL_GPL(nfs_lock);
873 
874 /*
875  * Lock a (portion of) a file
876  */
nfs_flock(struct file * filp,int cmd,struct file_lock * fl)877 int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
878 {
879 	struct inode *inode = filp->f_mapping->host;
880 	int is_local = 0;
881 
882 	dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n",
883 			filp, fl->c.flc_type, fl->c.flc_flags);
884 
885 	if (!(fl->c.flc_flags & FL_FLOCK))
886 		return -ENOLCK;
887 
888 	if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
889 		is_local = 1;
890 
891 	/* We're simulating flock() locks using posix locks on the server */
892 	if (lock_is_unlock(fl))
893 		return do_unlk(filp, cmd, fl, is_local);
894 	return do_setlk(filp, cmd, fl, is_local);
895 }
896 EXPORT_SYMBOL_GPL(nfs_flock);
897 
898 const struct file_operations nfs_file_operations = {
899 	.llseek		= nfs_file_llseek,
900 	.read_iter	= nfs_file_read,
901 	.write_iter	= nfs_file_write,
902 	.mmap		= nfs_file_mmap,
903 	.open		= nfs_file_open,
904 	.flush		= nfs_file_flush,
905 	.release	= nfs_file_release,
906 	.fsync		= nfs_file_fsync,
907 	.lock		= nfs_lock,
908 	.flock		= nfs_flock,
909 	.splice_read	= nfs_file_splice_read,
910 	.splice_write	= iter_file_splice_write,
911 	.check_flags	= nfs_check_flags,
912 	.setlease	= simple_nosetlease,
913 };
914 EXPORT_SYMBOL_GPL(nfs_file_operations);
915