xref: /linux/fs/9p/vfs_file.c (revision f2ee442115c9b6219083c019939a9cc0c9abb2f8)
1 /*
2  *  linux/fs/9p/vfs_file.c
3  *
4  * This file contians vfs file ops for 9P2000.
5  *
6  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
7  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License version 2
11  *  as published by the Free Software Foundation.
12  *
13  *  This program is distributed in the hope that it will be useful,
14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  *  GNU General Public License for more details.
17  *
18  *  You should have received a copy of the GNU General Public License
19  *  along with this program; if not, write to:
20  *  Free Software Foundation
21  *  51 Franklin Street, Fifth Floor
22  *  Boston, MA  02111-1301  USA
23  *
24  */
25 
26 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/fs.h>
29 #include <linux/sched.h>
30 #include <linux/file.h>
31 #include <linux/stat.h>
32 #include <linux/string.h>
33 #include <linux/inet.h>
34 #include <linux/list.h>
35 #include <linux/pagemap.h>
36 #include <linux/utsname.h>
37 #include <asm/uaccess.h>
38 #include <linux/idr.h>
39 #include <net/9p/9p.h>
40 #include <net/9p/client.h>
41 
42 #include "v9fs.h"
43 #include "v9fs_vfs.h"
44 #include "fid.h"
45 #include "cache.h"
46 
47 static const struct vm_operations_struct v9fs_file_vm_ops;
48 
49 /**
50  * v9fs_file_open - open a file (or directory)
51  * @inode: inode to be opened
52  * @file: file being opened
53  *
54  */
55 
56 int v9fs_file_open(struct inode *inode, struct file *file)
57 {
58 	int err;
59 	struct v9fs_inode *v9inode;
60 	struct v9fs_session_info *v9ses;
61 	struct p9_fid *fid;
62 	int omode;
63 
64 	P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
65 	v9inode = V9FS_I(inode);
66 	v9ses = v9fs_inode2v9ses(inode);
67 	if (v9fs_proto_dotl(v9ses))
68 		omode = v9fs_open_to_dotl_flags(file->f_flags);
69 	else
70 		omode = v9fs_uflags2omode(file->f_flags,
71 					v9fs_proto_dotu(v9ses));
72 	fid = file->private_data;
73 	if (!fid) {
74 		fid = v9fs_fid_clone(file->f_path.dentry);
75 		if (IS_ERR(fid))
76 			return PTR_ERR(fid);
77 
78 		err = p9_client_open(fid, omode);
79 		if (err < 0) {
80 			p9_client_clunk(fid);
81 			return err;
82 		}
83 		if (file->f_flags & O_TRUNC) {
84 			i_size_write(inode, 0);
85 			inode->i_blocks = 0;
86 		}
87 		if ((file->f_flags & O_APPEND) &&
88 			(!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
89 			generic_file_llseek(file, 0, SEEK_END);
90 	}
91 
92 	file->private_data = fid;
93 	mutex_lock(&v9inode->v_mutex);
94 	if (v9ses->cache && !v9inode->writeback_fid &&
95 	    ((file->f_flags & O_ACCMODE) != O_RDONLY)) {
96 		/*
97 		 * clone a fid and add it to writeback_fid
98 		 * we do it during open time instead of
99 		 * page dirty time via write_begin/page_mkwrite
100 		 * because we want write after unlink usecase
101 		 * to work.
102 		 */
103 		fid = v9fs_writeback_fid(file->f_path.dentry);
104 		if (IS_ERR(fid)) {
105 			err = PTR_ERR(fid);
106 			mutex_unlock(&v9inode->v_mutex);
107 			goto out_error;
108 		}
109 		v9inode->writeback_fid = (void *) fid;
110 	}
111 	mutex_unlock(&v9inode->v_mutex);
112 #ifdef CONFIG_9P_FSCACHE
113 	if (v9ses->cache)
114 		v9fs_cache_inode_set_cookie(inode, file);
115 #endif
116 	return 0;
117 out_error:
118 	p9_client_clunk(file->private_data);
119 	file->private_data = NULL;
120 	return err;
121 }
122 
123 /**
124  * v9fs_file_lock - lock a file (or directory)
125  * @filp: file to be locked
126  * @cmd: lock command
127  * @fl: file lock structure
128  *
129  * Bugs: this looks like a local only lock, we should extend into 9P
130  *       by using open exclusive
131  */
132 
133 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
134 {
135 	int res = 0;
136 	struct inode *inode = filp->f_path.dentry->d_inode;
137 
138 	P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
139 
140 	/* No mandatory locks */
141 	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
142 		return -ENOLCK;
143 
144 	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
145 		filemap_write_and_wait(inode->i_mapping);
146 		invalidate_mapping_pages(&inode->i_data, 0, -1);
147 	}
148 
149 	return res;
150 }
151 
152 static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
153 {
154 	struct p9_flock flock;
155 	struct p9_fid *fid;
156 	uint8_t status;
157 	int res = 0;
158 	unsigned char fl_type;
159 
160 	fid = filp->private_data;
161 	BUG_ON(fid == NULL);
162 
163 	if ((fl->fl_flags & FL_POSIX) != FL_POSIX)
164 		BUG();
165 
166 	res = posix_lock_file_wait(filp, fl);
167 	if (res < 0)
168 		goto out;
169 
170 	/* convert posix lock to p9 tlock args */
171 	memset(&flock, 0, sizeof(flock));
172 	/* map the lock type */
173 	switch (fl->fl_type) {
174 	case F_RDLCK:
175 		flock.type = P9_LOCK_TYPE_RDLCK;
176 		break;
177 	case F_WRLCK:
178 		flock.type = P9_LOCK_TYPE_WRLCK;
179 		break;
180 	case F_UNLCK:
181 		flock.type = P9_LOCK_TYPE_UNLCK;
182 		break;
183 	}
184 	flock.start = fl->fl_start;
185 	if (fl->fl_end == OFFSET_MAX)
186 		flock.length = 0;
187 	else
188 		flock.length = fl->fl_end - fl->fl_start + 1;
189 	flock.proc_id = fl->fl_pid;
190 	flock.client_id = utsname()->nodename;
191 	if (IS_SETLKW(cmd))
192 		flock.flags = P9_LOCK_FLAGS_BLOCK;
193 
194 	/*
195 	 * if its a blocked request and we get P9_LOCK_BLOCKED as the status
196 	 * for lock request, keep on trying
197 	 */
198 	for (;;) {
199 		res = p9_client_lock_dotl(fid, &flock, &status);
200 		if (res < 0)
201 			break;
202 
203 		if (status != P9_LOCK_BLOCKED)
204 			break;
205 		if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
206 			break;
207 		schedule_timeout_interruptible(P9_LOCK_TIMEOUT);
208 	}
209 
210 	/* map 9p status to VFS status */
211 	switch (status) {
212 	case P9_LOCK_SUCCESS:
213 		res = 0;
214 		break;
215 	case P9_LOCK_BLOCKED:
216 		res = -EAGAIN;
217 		break;
218 	case P9_LOCK_ERROR:
219 	case P9_LOCK_GRACE:
220 		res = -ENOLCK;
221 		break;
222 	default:
223 		BUG();
224 	}
225 
226 	/*
227 	 * incase server returned error for lock request, revert
228 	 * it locally
229 	 */
230 	if (res < 0 && fl->fl_type != F_UNLCK) {
231 		fl_type = fl->fl_type;
232 		fl->fl_type = F_UNLCK;
233 		res = posix_lock_file_wait(filp, fl);
234 		fl->fl_type = fl_type;
235 	}
236 out:
237 	return res;
238 }
239 
240 static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
241 {
242 	struct p9_getlock glock;
243 	struct p9_fid *fid;
244 	int res = 0;
245 
246 	fid = filp->private_data;
247 	BUG_ON(fid == NULL);
248 
249 	posix_test_lock(filp, fl);
250 	/*
251 	 * if we have a conflicting lock locally, no need to validate
252 	 * with server
253 	 */
254 	if (fl->fl_type != F_UNLCK)
255 		return res;
256 
257 	/* convert posix lock to p9 tgetlock args */
258 	memset(&glock, 0, sizeof(glock));
259 	glock.type  = P9_LOCK_TYPE_UNLCK;
260 	glock.start = fl->fl_start;
261 	if (fl->fl_end == OFFSET_MAX)
262 		glock.length = 0;
263 	else
264 		glock.length = fl->fl_end - fl->fl_start + 1;
265 	glock.proc_id = fl->fl_pid;
266 	glock.client_id = utsname()->nodename;
267 
268 	res = p9_client_getlock_dotl(fid, &glock);
269 	if (res < 0)
270 		return res;
271 	/* map 9p lock type to os lock type */
272 	switch (glock.type) {
273 	case P9_LOCK_TYPE_RDLCK:
274 		fl->fl_type = F_RDLCK;
275 		break;
276 	case P9_LOCK_TYPE_WRLCK:
277 		fl->fl_type = F_WRLCK;
278 		break;
279 	case P9_LOCK_TYPE_UNLCK:
280 		fl->fl_type = F_UNLCK;
281 		break;
282 	}
283 	if (glock.type != P9_LOCK_TYPE_UNLCK) {
284 		fl->fl_start = glock.start;
285 		if (glock.length == 0)
286 			fl->fl_end = OFFSET_MAX;
287 		else
288 			fl->fl_end = glock.start + glock.length - 1;
289 		fl->fl_pid = glock.proc_id;
290 	}
291 	return res;
292 }
293 
294 /**
295  * v9fs_file_lock_dotl - lock a file (or directory)
296  * @filp: file to be locked
297  * @cmd: lock command
298  * @fl: file lock structure
299  *
300  */
301 
302 static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
303 {
304 	struct inode *inode = filp->f_path.dentry->d_inode;
305 	int ret = -ENOLCK;
306 
307 	P9_DPRINTK(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n", filp,
308 				cmd, fl, filp->f_path.dentry->d_name.name);
309 
310 	/* No mandatory locks */
311 	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
312 		goto out_err;
313 
314 	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
315 		filemap_write_and_wait(inode->i_mapping);
316 		invalidate_mapping_pages(&inode->i_data, 0, -1);
317 	}
318 
319 	if (IS_SETLK(cmd) || IS_SETLKW(cmd))
320 		ret = v9fs_file_do_lock(filp, cmd, fl);
321 	else if (IS_GETLK(cmd))
322 		ret = v9fs_file_getlock(filp, fl);
323 	else
324 		ret = -EINVAL;
325 out_err:
326 	return ret;
327 }
328 
329 /**
330  * v9fs_file_flock_dotl - lock a file
331  * @filp: file to be locked
332  * @cmd: lock command
333  * @fl: file lock structure
334  *
335  */
336 
337 static int v9fs_file_flock_dotl(struct file *filp, int cmd,
338 	struct file_lock *fl)
339 {
340 	struct inode *inode = filp->f_path.dentry->d_inode;
341 	int ret = -ENOLCK;
342 
343 	P9_DPRINTK(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %s\n", filp,
344 				cmd, fl, filp->f_path.dentry->d_name.name);
345 
346 	/* No mandatory locks */
347 	if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
348 		goto out_err;
349 
350 	if (!(fl->fl_flags & FL_FLOCK))
351 		goto out_err;
352 
353 	if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
354 		filemap_write_and_wait(inode->i_mapping);
355 		invalidate_mapping_pages(&inode->i_data, 0, -1);
356 	}
357 	/* Convert flock to posix lock */
358 	fl->fl_owner = (fl_owner_t)filp;
359 	fl->fl_start = 0;
360 	fl->fl_end = OFFSET_MAX;
361 	fl->fl_flags |= FL_POSIX;
362 	fl->fl_flags ^= FL_FLOCK;
363 
364 	if (IS_SETLK(cmd) | IS_SETLKW(cmd))
365 		ret = v9fs_file_do_lock(filp, cmd, fl);
366 	else
367 		ret = -EINVAL;
368 out_err:
369 	return ret;
370 }
371 
372 /**
373  * v9fs_fid_readn - read from a fid
374  * @fid: fid to read
375  * @data: data buffer to read data into
376  * @udata: user data buffer to read data into
377  * @count: size of buffer
378  * @offset: offset at which to read data
379  *
380  */
381 ssize_t
382 v9fs_fid_readn(struct p9_fid *fid, char *data, char __user *udata, u32 count,
383 	       u64 offset)
384 {
385 	int n, total, size;
386 
387 	P9_DPRINTK(P9_DEBUG_VFS, "fid %d offset %llu count %d\n", fid->fid,
388 		   (long long unsigned) offset, count);
389 	n = 0;
390 	total = 0;
391 	size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
392 	do {
393 		n = p9_client_read(fid, data, udata, offset, count);
394 		if (n <= 0)
395 			break;
396 
397 		if (data)
398 			data += n;
399 		if (udata)
400 			udata += n;
401 
402 		offset += n;
403 		count -= n;
404 		total += n;
405 	} while (count > 0 && n == size);
406 
407 	if (n < 0)
408 		total = n;
409 
410 	return total;
411 }
412 
413 /**
414  * v9fs_file_readn - read from a file
415  * @filp: file pointer to read
416  * @data: data buffer to read data into
417  * @udata: user data buffer to read data into
418  * @count: size of buffer
419  * @offset: offset at which to read data
420  *
421  */
422 ssize_t
423 v9fs_file_readn(struct file *filp, char *data, char __user *udata, u32 count,
424 	       u64 offset)
425 {
426 	return v9fs_fid_readn(filp->private_data, data, udata, count, offset);
427 }
428 
429 /**
430  * v9fs_file_read - read from a file
431  * @filp: file pointer to read
432  * @udata: user data buffer to read data into
433  * @count: size of buffer
434  * @offset: offset at which to read data
435  *
436  */
437 
438 static ssize_t
439 v9fs_file_read(struct file *filp, char __user *udata, size_t count,
440 	       loff_t * offset)
441 {
442 	int ret;
443 	struct p9_fid *fid;
444 	size_t size;
445 
446 	P9_DPRINTK(P9_DEBUG_VFS, "count %zu offset %lld\n", count, *offset);
447 	fid = filp->private_data;
448 
449 	size = fid->iounit ? fid->iounit : fid->clnt->msize - P9_IOHDRSZ;
450 	if (count > size)
451 		ret = v9fs_file_readn(filp, NULL, udata, count, *offset);
452 	else
453 		ret = p9_client_read(fid, NULL, udata, *offset, count);
454 
455 	if (ret > 0)
456 		*offset += ret;
457 
458 	return ret;
459 }
460 
461 ssize_t
462 v9fs_file_write_internal(struct inode *inode, struct p9_fid *fid,
463 			 const char __user *data, size_t count,
464 			 loff_t *offset, int invalidate)
465 {
466 	int n;
467 	loff_t i_size;
468 	size_t total = 0;
469 	struct p9_client *clnt;
470 	loff_t origin = *offset;
471 	unsigned long pg_start, pg_end;
472 
473 	P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
474 		(int)count, (int)*offset);
475 
476 	clnt = fid->clnt;
477 	do {
478 		n = p9_client_write(fid, NULL, data+total, origin+total, count);
479 		if (n <= 0)
480 			break;
481 		count -= n;
482 		total += n;
483 	} while (count > 0);
484 
485 	if (invalidate && (total > 0)) {
486 		pg_start = origin >> PAGE_CACHE_SHIFT;
487 		pg_end = (origin + total - 1) >> PAGE_CACHE_SHIFT;
488 		if (inode->i_mapping && inode->i_mapping->nrpages)
489 			invalidate_inode_pages2_range(inode->i_mapping,
490 						      pg_start, pg_end);
491 		*offset += total;
492 		i_size = i_size_read(inode);
493 		if (*offset > i_size) {
494 			inode_add_bytes(inode, *offset - i_size);
495 			i_size_write(inode, *offset);
496 		}
497 	}
498 	if (n < 0)
499 		return n;
500 
501 	return total;
502 }
503 
504 /**
505  * v9fs_file_write - write to a file
506  * @filp: file pointer to write
507  * @data: data buffer to write data from
508  * @count: size of buffer
509  * @offset: offset at which to write data
510  *
511  */
512 static ssize_t
513 v9fs_file_write(struct file *filp, const char __user * data,
514 		size_t count, loff_t *offset)
515 {
516 	ssize_t retval = 0;
517 	loff_t origin = *offset;
518 
519 
520 	retval = generic_write_checks(filp, &origin, &count, 0);
521 	if (retval)
522 		goto out;
523 
524 	retval = -EINVAL;
525 	if ((ssize_t) count < 0)
526 		goto out;
527 	retval = 0;
528 	if (!count)
529 		goto out;
530 
531 	retval = v9fs_file_write_internal(filp->f_path.dentry->d_inode,
532 					filp->private_data,
533 					data, count, &origin, 1);
534 	/* update offset on successful write */
535 	if (retval > 0)
536 		*offset = origin;
537 out:
538 	return retval;
539 }
540 
541 
542 static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
543 			   int datasync)
544 {
545 	struct p9_fid *fid;
546 	struct inode *inode = filp->f_mapping->host;
547 	struct p9_wstat wstat;
548 	int retval;
549 
550 	retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
551 	if (retval)
552 		return retval;
553 
554 	mutex_lock(&inode->i_mutex);
555 	P9_DPRINTK(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
556 
557 	fid = filp->private_data;
558 	v9fs_blank_wstat(&wstat);
559 
560 	retval = p9_client_wstat(fid, &wstat);
561 	mutex_unlock(&inode->i_mutex);
562 
563 	return retval;
564 }
565 
566 int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
567 			 int datasync)
568 {
569 	struct p9_fid *fid;
570 	struct inode *inode = filp->f_mapping->host;
571 	int retval;
572 
573 	retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
574 	if (retval)
575 		return retval;
576 
577 	mutex_lock(&inode->i_mutex);
578 	P9_DPRINTK(P9_DEBUG_VFS, "v9fs_file_fsync_dotl: filp %p datasync %x\n",
579 			filp, datasync);
580 
581 	fid = filp->private_data;
582 
583 	retval = p9_client_fsync(fid, datasync);
584 	mutex_unlock(&inode->i_mutex);
585 
586 	return retval;
587 }
588 
589 static int
590 v9fs_file_mmap(struct file *file, struct vm_area_struct *vma)
591 {
592 	int retval;
593 
594 	retval = generic_file_mmap(file, vma);
595 	if (!retval)
596 		vma->vm_ops = &v9fs_file_vm_ops;
597 
598 	return retval;
599 }
600 
601 static int
602 v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
603 {
604 	struct v9fs_inode *v9inode;
605 	struct page *page = vmf->page;
606 	struct file *filp = vma->vm_file;
607 	struct inode *inode = filp->f_path.dentry->d_inode;
608 
609 
610 	P9_DPRINTK(P9_DEBUG_VFS, "page %p fid %lx\n",
611 		   page, (unsigned long)filp->private_data);
612 
613 	v9inode = V9FS_I(inode);
614 	/* make sure the cache has finished storing the page */
615 	v9fs_fscache_wait_on_page_write(inode, page);
616 	BUG_ON(!v9inode->writeback_fid);
617 	lock_page(page);
618 	if (page->mapping != inode->i_mapping)
619 		goto out_unlock;
620 
621 	return VM_FAULT_LOCKED;
622 out_unlock:
623 	unlock_page(page);
624 	return VM_FAULT_NOPAGE;
625 }
626 
627 static ssize_t
628 v9fs_direct_read(struct file *filp, char __user *udata, size_t count,
629 		 loff_t *offsetp)
630 {
631 	loff_t size, offset;
632 	struct inode *inode;
633 	struct address_space *mapping;
634 
635 	offset = *offsetp;
636 	mapping = filp->f_mapping;
637 	inode = mapping->host;
638 	if (!count)
639 		return 0;
640 	size = i_size_read(inode);
641 	if (offset < size)
642 		filemap_write_and_wait_range(mapping, offset,
643 					     offset + count - 1);
644 
645 	return v9fs_file_read(filp, udata, count, offsetp);
646 }
647 
648 /**
649  * v9fs_cached_file_read - read from a file
650  * @filp: file pointer to read
651  * @udata: user data buffer to read data into
652  * @count: size of buffer
653  * @offset: offset at which to read data
654  *
655  */
656 static ssize_t
657 v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,
658 		      loff_t *offset)
659 {
660 	if (filp->f_flags & O_DIRECT)
661 		return v9fs_direct_read(filp, data, count, offset);
662 	return do_sync_read(filp, data, count, offset);
663 }
664 
665 static ssize_t
666 v9fs_direct_write(struct file *filp, const char __user * data,
667 		  size_t count, loff_t *offsetp)
668 {
669 	loff_t offset;
670 	ssize_t retval;
671 	struct inode *inode;
672 	struct address_space *mapping;
673 
674 	offset = *offsetp;
675 	mapping = filp->f_mapping;
676 	inode = mapping->host;
677 	if (!count)
678 		return 0;
679 
680 	mutex_lock(&inode->i_mutex);
681 	retval = filemap_write_and_wait_range(mapping, offset,
682 					      offset + count - 1);
683 	if (retval)
684 		goto err_out;
685 	/*
686 	 * After a write we want buffered reads to be sure to go to disk to get
687 	 * the new data.  We invalidate clean cached page from the region we're
688 	 * about to write.  We do this *before* the write so that if we fail
689 	 * here we fall back to buffered write
690 	 */
691 	if (mapping->nrpages) {
692 		pgoff_t pg_start = offset >> PAGE_CACHE_SHIFT;
693 		pgoff_t pg_end   = (offset + count - 1) >> PAGE_CACHE_SHIFT;
694 
695 		retval = invalidate_inode_pages2_range(mapping,
696 							pg_start, pg_end);
697 		/*
698 		 * If a page can not be invalidated, fall back
699 		 * to buffered write.
700 		 */
701 		if (retval) {
702 			if (retval == -EBUSY)
703 				goto buff_write;
704 			goto err_out;
705 		}
706 	}
707 	retval = v9fs_file_write(filp, data, count, offsetp);
708 err_out:
709 	mutex_unlock(&inode->i_mutex);
710 	return retval;
711 
712 buff_write:
713 	mutex_unlock(&inode->i_mutex);
714 	return do_sync_write(filp, data, count, offsetp);
715 }
716 
717 /**
718  * v9fs_cached_file_write - write to a file
719  * @filp: file pointer to write
720  * @data: data buffer to write data from
721  * @count: size of buffer
722  * @offset: offset at which to write data
723  *
724  */
725 static ssize_t
726 v9fs_cached_file_write(struct file *filp, const char __user * data,
727 		       size_t count, loff_t *offset)
728 {
729 
730 	if (filp->f_flags & O_DIRECT)
731 		return v9fs_direct_write(filp, data, count, offset);
732 	return do_sync_write(filp, data, count, offset);
733 }
734 
735 static const struct vm_operations_struct v9fs_file_vm_ops = {
736 	.fault = filemap_fault,
737 	.page_mkwrite = v9fs_vm_page_mkwrite,
738 };
739 
740 
741 const struct file_operations v9fs_cached_file_operations = {
742 	.llseek = generic_file_llseek,
743 	.read = v9fs_cached_file_read,
744 	.write = v9fs_cached_file_write,
745 	.aio_read = generic_file_aio_read,
746 	.aio_write = generic_file_aio_write,
747 	.open = v9fs_file_open,
748 	.release = v9fs_dir_release,
749 	.lock = v9fs_file_lock,
750 	.mmap = v9fs_file_mmap,
751 	.fsync = v9fs_file_fsync,
752 };
753 
754 const struct file_operations v9fs_cached_file_operations_dotl = {
755 	.llseek = generic_file_llseek,
756 	.read = v9fs_cached_file_read,
757 	.write = v9fs_cached_file_write,
758 	.aio_read = generic_file_aio_read,
759 	.aio_write = generic_file_aio_write,
760 	.open = v9fs_file_open,
761 	.release = v9fs_dir_release,
762 	.lock = v9fs_file_lock_dotl,
763 	.flock = v9fs_file_flock_dotl,
764 	.mmap = v9fs_file_mmap,
765 	.fsync = v9fs_file_fsync_dotl,
766 };
767 
768 const struct file_operations v9fs_file_operations = {
769 	.llseek = generic_file_llseek,
770 	.read = v9fs_file_read,
771 	.write = v9fs_file_write,
772 	.open = v9fs_file_open,
773 	.release = v9fs_dir_release,
774 	.lock = v9fs_file_lock,
775 	.mmap = generic_file_readonly_mmap,
776 	.fsync = v9fs_file_fsync,
777 };
778 
779 const struct file_operations v9fs_file_operations_dotl = {
780 	.llseek = generic_file_llseek,
781 	.read = v9fs_file_read,
782 	.write = v9fs_file_write,
783 	.open = v9fs_file_open,
784 	.release = v9fs_dir_release,
785 	.lock = v9fs_file_lock_dotl,
786 	.flock = v9fs_file_flock_dotl,
787 	.mmap = generic_file_readonly_mmap,
788 	.fsync = v9fs_file_fsync_dotl,
789 };
790