Merge branch 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason...
[deliverable/linux.git] / fs / 9p / vfs_file.c
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 <linux/uio.h>
40 #include <linux/slab.h>
41 #include <net/9p/9p.h>
42 #include <net/9p/client.h>
43
44 #include "v9fs.h"
45 #include "v9fs_vfs.h"
46 #include "fid.h"
47 #include "cache.h"
48
49 static const struct vm_operations_struct v9fs_file_vm_ops;
50 static const struct vm_operations_struct v9fs_mmap_file_vm_ops;
51
52 /**
53 * v9fs_file_open - open a file (or directory)
54 * @inode: inode to be opened
55 * @file: file being opened
56 *
57 */
58
59 int v9fs_file_open(struct inode *inode, struct file *file)
60 {
61 int err;
62 struct v9fs_inode *v9inode;
63 struct v9fs_session_info *v9ses;
64 struct p9_fid *fid;
65 int omode;
66
67 p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, file);
68 v9inode = V9FS_I(inode);
69 v9ses = v9fs_inode2v9ses(inode);
70 if (v9fs_proto_dotl(v9ses))
71 omode = v9fs_open_to_dotl_flags(file->f_flags);
72 else
73 omode = v9fs_uflags2omode(file->f_flags,
74 v9fs_proto_dotu(v9ses));
75 fid = file->private_data;
76 if (!fid) {
77 fid = v9fs_fid_clone(file->f_path.dentry);
78 if (IS_ERR(fid))
79 return PTR_ERR(fid);
80
81 err = p9_client_open(fid, omode);
82 if (err < 0) {
83 p9_client_clunk(fid);
84 return err;
85 }
86 if ((file->f_flags & O_APPEND) &&
87 (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)))
88 generic_file_llseek(file, 0, SEEK_END);
89 }
90
91 file->private_data = fid;
92 mutex_lock(&v9inode->v_mutex);
93 if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
94 !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 if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
113 v9fs_cache_inode_set_cookie(inode, file);
114 return 0;
115 out_error:
116 p9_client_clunk(file->private_data);
117 file->private_data = NULL;
118 return err;
119 }
120
121 /**
122 * v9fs_file_lock - lock a file (or directory)
123 * @filp: file to be locked
124 * @cmd: lock command
125 * @fl: file lock structure
126 *
127 * Bugs: this looks like a local only lock, we should extend into 9P
128 * by using open exclusive
129 */
130
131 static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
132 {
133 int res = 0;
134 struct inode *inode = file_inode(filp);
135
136 p9_debug(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
137
138 /* No mandatory locks */
139 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
140 return -ENOLCK;
141
142 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
143 filemap_write_and_wait(inode->i_mapping);
144 invalidate_mapping_pages(&inode->i_data, 0, -1);
145 }
146
147 return res;
148 }
149
150 static int v9fs_file_do_lock(struct file *filp, int cmd, struct file_lock *fl)
151 {
152 struct p9_flock flock;
153 struct p9_fid *fid;
154 uint8_t status = P9_LOCK_ERROR;
155 int res = 0;
156 unsigned char fl_type;
157
158 fid = filp->private_data;
159 BUG_ON(fid == NULL);
160
161 if ((fl->fl_flags & FL_POSIX) != FL_POSIX)
162 BUG();
163
164 res = posix_lock_file_wait(filp, fl);
165 if (res < 0)
166 goto out;
167
168 /* convert posix lock to p9 tlock args */
169 memset(&flock, 0, sizeof(flock));
170 /* map the lock type */
171 switch (fl->fl_type) {
172 case F_RDLCK:
173 flock.type = P9_LOCK_TYPE_RDLCK;
174 break;
175 case F_WRLCK:
176 flock.type = P9_LOCK_TYPE_WRLCK;
177 break;
178 case F_UNLCK:
179 flock.type = P9_LOCK_TYPE_UNLCK;
180 break;
181 }
182 flock.start = fl->fl_start;
183 if (fl->fl_end == OFFSET_MAX)
184 flock.length = 0;
185 else
186 flock.length = fl->fl_end - fl->fl_start + 1;
187 flock.proc_id = fl->fl_pid;
188 flock.client_id = fid->clnt->name;
189 if (IS_SETLKW(cmd))
190 flock.flags = P9_LOCK_FLAGS_BLOCK;
191
192 /*
193 * if its a blocked request and we get P9_LOCK_BLOCKED as the status
194 * for lock request, keep on trying
195 */
196 for (;;) {
197 res = p9_client_lock_dotl(fid, &flock, &status);
198 if (res < 0)
199 goto out_unlock;
200
201 if (status != P9_LOCK_BLOCKED)
202 break;
203 if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
204 break;
205 if (schedule_timeout_interruptible(P9_LOCK_TIMEOUT) != 0)
206 break;
207 }
208
209 /* map 9p status to VFS status */
210 switch (status) {
211 case P9_LOCK_SUCCESS:
212 res = 0;
213 break;
214 case P9_LOCK_BLOCKED:
215 res = -EAGAIN;
216 break;
217 default:
218 WARN_ONCE(1, "unknown lock status code: %d\n", status);
219 /* fallthough */
220 case P9_LOCK_ERROR:
221 case P9_LOCK_GRACE:
222 res = -ENOLCK;
223 break;
224 }
225
226 out_unlock:
227 /*
228 * incase server returned error for lock request, revert
229 * it locally
230 */
231 if (res < 0 && fl->fl_type != F_UNLCK) {
232 fl_type = fl->fl_type;
233 fl->fl_type = F_UNLCK;
234 res = posix_lock_file_wait(filp, fl);
235 fl->fl_type = fl_type;
236 }
237 out:
238 return res;
239 }
240
241 static int v9fs_file_getlock(struct file *filp, struct file_lock *fl)
242 {
243 struct p9_getlock glock;
244 struct p9_fid *fid;
245 int res = 0;
246
247 fid = filp->private_data;
248 BUG_ON(fid == NULL);
249
250 posix_test_lock(filp, fl);
251 /*
252 * if we have a conflicting lock locally, no need to validate
253 * with server
254 */
255 if (fl->fl_type != F_UNLCK)
256 return res;
257
258 /* convert posix lock to p9 tgetlock args */
259 memset(&glock, 0, sizeof(glock));
260 glock.type = P9_LOCK_TYPE_UNLCK;
261 glock.start = fl->fl_start;
262 if (fl->fl_end == OFFSET_MAX)
263 glock.length = 0;
264 else
265 glock.length = fl->fl_end - fl->fl_start + 1;
266 glock.proc_id = fl->fl_pid;
267 glock.client_id = fid->clnt->name;
268
269 res = p9_client_getlock_dotl(fid, &glock);
270 if (res < 0)
271 return res;
272 /* map 9p lock type to os lock type */
273 switch (glock.type) {
274 case P9_LOCK_TYPE_RDLCK:
275 fl->fl_type = F_RDLCK;
276 break;
277 case P9_LOCK_TYPE_WRLCK:
278 fl->fl_type = F_WRLCK;
279 break;
280 case P9_LOCK_TYPE_UNLCK:
281 fl->fl_type = F_UNLCK;
282 break;
283 }
284 if (glock.type != P9_LOCK_TYPE_UNLCK) {
285 fl->fl_start = glock.start;
286 if (glock.length == 0)
287 fl->fl_end = OFFSET_MAX;
288 else
289 fl->fl_end = glock.start + glock.length - 1;
290 fl->fl_pid = glock.proc_id;
291 }
292 kfree(glock.client_id);
293 return res;
294 }
295
296 /**
297 * v9fs_file_lock_dotl - lock a file (or directory)
298 * @filp: file to be locked
299 * @cmd: lock command
300 * @fl: file lock structure
301 *
302 */
303
304 static int v9fs_file_lock_dotl(struct file *filp, int cmd, struct file_lock *fl)
305 {
306 struct inode *inode = file_inode(filp);
307 int ret = -ENOLCK;
308
309 p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
310 filp, cmd, fl, filp);
311
312 /* No mandatory locks */
313 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
314 goto out_err;
315
316 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
317 filemap_write_and_wait(inode->i_mapping);
318 invalidate_mapping_pages(&inode->i_data, 0, -1);
319 }
320
321 if (IS_SETLK(cmd) || IS_SETLKW(cmd))
322 ret = v9fs_file_do_lock(filp, cmd, fl);
323 else if (IS_GETLK(cmd))
324 ret = v9fs_file_getlock(filp, fl);
325 else
326 ret = -EINVAL;
327 out_err:
328 return ret;
329 }
330
331 /**
332 * v9fs_file_flock_dotl - lock a file
333 * @filp: file to be locked
334 * @cmd: lock command
335 * @fl: file lock structure
336 *
337 */
338
339 static int v9fs_file_flock_dotl(struct file *filp, int cmd,
340 struct file_lock *fl)
341 {
342 struct inode *inode = file_inode(filp);
343 int ret = -ENOLCK;
344
345 p9_debug(P9_DEBUG_VFS, "filp: %p cmd:%d lock: %p name: %pD\n",
346 filp, cmd, fl, filp);
347
348 /* No mandatory locks */
349 if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
350 goto out_err;
351
352 if (!(fl->fl_flags & FL_FLOCK))
353 goto out_err;
354
355 if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
356 filemap_write_and_wait(inode->i_mapping);
357 invalidate_mapping_pages(&inode->i_data, 0, -1);
358 }
359 /* Convert flock to posix lock */
360 fl->fl_flags |= FL_POSIX;
361 fl->fl_flags ^= FL_FLOCK;
362
363 if (IS_SETLK(cmd) | IS_SETLKW(cmd))
364 ret = v9fs_file_do_lock(filp, cmd, fl);
365 else
366 ret = -EINVAL;
367 out_err:
368 return ret;
369 }
370
371 /**
372 * v9fs_file_read - read from a file
373 * @filp: file pointer to read
374 * @udata: user data buffer to read data into
375 * @count: size of buffer
376 * @offset: offset at which to read data
377 *
378 */
379
380 static ssize_t
381 v9fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
382 {
383 struct p9_fid *fid = iocb->ki_filp->private_data;
384 int ret, err = 0;
385
386 p9_debug(P9_DEBUG_VFS, "count %zu offset %lld\n",
387 iov_iter_count(to), iocb->ki_pos);
388
389 ret = p9_client_read(fid, iocb->ki_pos, to, &err);
390 if (!ret)
391 return err;
392
393 iocb->ki_pos += ret;
394 return ret;
395 }
396
397 /**
398 * v9fs_file_write - write to a file
399 * @filp: file pointer to write
400 * @data: data buffer to write data from
401 * @count: size of buffer
402 * @offset: offset at which to write data
403 *
404 */
405 static ssize_t
406 v9fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
407 {
408 struct file *file = iocb->ki_filp;
409 ssize_t retval;
410 loff_t origin;
411 int err = 0;
412
413 retval = generic_write_checks(iocb, from);
414 if (retval <= 0)
415 return retval;
416
417 origin = iocb->ki_pos;
418 retval = p9_client_write(file->private_data, iocb->ki_pos, from, &err);
419 if (retval > 0) {
420 struct inode *inode = file_inode(file);
421 loff_t i_size;
422 unsigned long pg_start, pg_end;
423 pg_start = origin >> PAGE_CACHE_SHIFT;
424 pg_end = (origin + retval - 1) >> PAGE_CACHE_SHIFT;
425 if (inode->i_mapping && inode->i_mapping->nrpages)
426 invalidate_inode_pages2_range(inode->i_mapping,
427 pg_start, pg_end);
428 iocb->ki_pos += retval;
429 i_size = i_size_read(inode);
430 if (iocb->ki_pos > i_size) {
431 inode_add_bytes(inode, iocb->ki_pos - i_size);
432 i_size_write(inode, iocb->ki_pos);
433 }
434 return retval;
435 }
436 return err;
437 }
438
439 static int v9fs_file_fsync(struct file *filp, loff_t start, loff_t end,
440 int datasync)
441 {
442 struct p9_fid *fid;
443 struct inode *inode = filp->f_mapping->host;
444 struct p9_wstat wstat;
445 int retval;
446
447 retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
448 if (retval)
449 return retval;
450
451 mutex_lock(&inode->i_mutex);
452 p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
453
454 fid = filp->private_data;
455 v9fs_blank_wstat(&wstat);
456
457 retval = p9_client_wstat(fid, &wstat);
458 mutex_unlock(&inode->i_mutex);
459
460 return retval;
461 }
462
463 int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
464 int datasync)
465 {
466 struct p9_fid *fid;
467 struct inode *inode = filp->f_mapping->host;
468 int retval;
469
470 retval = filemap_write_and_wait_range(inode->i_mapping, start, end);
471 if (retval)
472 return retval;
473
474 mutex_lock(&inode->i_mutex);
475 p9_debug(P9_DEBUG_VFS, "filp %p datasync %x\n", filp, datasync);
476
477 fid = filp->private_data;
478
479 retval = p9_client_fsync(fid, datasync);
480 mutex_unlock(&inode->i_mutex);
481
482 return retval;
483 }
484
485 static int
486 v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
487 {
488 int retval;
489
490
491 retval = generic_file_mmap(filp, vma);
492 if (!retval)
493 vma->vm_ops = &v9fs_file_vm_ops;
494
495 return retval;
496 }
497
498 static int
499 v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma)
500 {
501 int retval;
502 struct inode *inode;
503 struct v9fs_inode *v9inode;
504 struct p9_fid *fid;
505
506 inode = file_inode(filp);
507 v9inode = V9FS_I(inode);
508 mutex_lock(&v9inode->v_mutex);
509 if (!v9inode->writeback_fid &&
510 (vma->vm_flags & VM_WRITE)) {
511 /*
512 * clone a fid and add it to writeback_fid
513 * we do it during mmap instead of
514 * page dirty time via write_begin/page_mkwrite
515 * because we want write after unlink usecase
516 * to work.
517 */
518 fid = v9fs_writeback_fid(filp->f_path.dentry);
519 if (IS_ERR(fid)) {
520 retval = PTR_ERR(fid);
521 mutex_unlock(&v9inode->v_mutex);
522 return retval;
523 }
524 v9inode->writeback_fid = (void *) fid;
525 }
526 mutex_unlock(&v9inode->v_mutex);
527
528 retval = generic_file_mmap(filp, vma);
529 if (!retval)
530 vma->vm_ops = &v9fs_mmap_file_vm_ops;
531
532 return retval;
533 }
534
535 static int
536 v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
537 {
538 struct v9fs_inode *v9inode;
539 struct page *page = vmf->page;
540 struct file *filp = vma->vm_file;
541 struct inode *inode = file_inode(filp);
542
543
544 p9_debug(P9_DEBUG_VFS, "page %p fid %lx\n",
545 page, (unsigned long)filp->private_data);
546
547 /* Update file times before taking page lock */
548 file_update_time(filp);
549
550 v9inode = V9FS_I(inode);
551 /* make sure the cache has finished storing the page */
552 v9fs_fscache_wait_on_page_write(inode, page);
553 BUG_ON(!v9inode->writeback_fid);
554 lock_page(page);
555 if (page->mapping != inode->i_mapping)
556 goto out_unlock;
557 wait_for_stable_page(page);
558
559 return VM_FAULT_LOCKED;
560 out_unlock:
561 unlock_page(page);
562 return VM_FAULT_NOPAGE;
563 }
564
565 /**
566 * v9fs_mmap_file_read - read from a file
567 * @filp: file pointer to read
568 * @data: user data buffer to read data into
569 * @count: size of buffer
570 * @offset: offset at which to read data
571 *
572 */
573 static ssize_t
574 v9fs_mmap_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
575 {
576 /* TODO: Check if there are dirty pages */
577 return v9fs_file_read_iter(iocb, to);
578 }
579
580 /**
581 * v9fs_mmap_file_write - write to a file
582 * @filp: file pointer to write
583 * @data: data buffer to write data from
584 * @count: size of buffer
585 * @offset: offset at which to write data
586 *
587 */
588 static ssize_t
589 v9fs_mmap_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
590 {
591 /*
592 * TODO: invalidate mmaps on filp's inode between
593 * offset and offset+count
594 */
595 return v9fs_file_write_iter(iocb, from);
596 }
597
598 static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
599 {
600 struct inode *inode;
601
602 struct writeback_control wbc = {
603 .nr_to_write = LONG_MAX,
604 .sync_mode = WB_SYNC_ALL,
605 .range_start = vma->vm_pgoff * PAGE_SIZE,
606 /* absolute end, byte at end included */
607 .range_end = vma->vm_pgoff * PAGE_SIZE +
608 (vma->vm_end - vma->vm_start - 1),
609 };
610
611
612 p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
613
614 inode = file_inode(vma->vm_file);
615
616 if (!mapping_cap_writeback_dirty(inode->i_mapping))
617 wbc.nr_to_write = 0;
618
619 might_sleep();
620 sync_inode(inode, &wbc);
621 }
622
623
624 static const struct vm_operations_struct v9fs_file_vm_ops = {
625 .fault = filemap_fault,
626 .map_pages = filemap_map_pages,
627 .page_mkwrite = v9fs_vm_page_mkwrite,
628 };
629
630 static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
631 .close = v9fs_mmap_vm_close,
632 .fault = filemap_fault,
633 .map_pages = filemap_map_pages,
634 .page_mkwrite = v9fs_vm_page_mkwrite,
635 };
636
637
638 const struct file_operations v9fs_cached_file_operations = {
639 .llseek = generic_file_llseek,
640 .read_iter = generic_file_read_iter,
641 .write_iter = generic_file_write_iter,
642 .open = v9fs_file_open,
643 .release = v9fs_dir_release,
644 .lock = v9fs_file_lock,
645 .mmap = v9fs_file_mmap,
646 .fsync = v9fs_file_fsync,
647 };
648
649 const struct file_operations v9fs_cached_file_operations_dotl = {
650 .llseek = generic_file_llseek,
651 .read_iter = generic_file_read_iter,
652 .write_iter = generic_file_write_iter,
653 .open = v9fs_file_open,
654 .release = v9fs_dir_release,
655 .lock = v9fs_file_lock_dotl,
656 .flock = v9fs_file_flock_dotl,
657 .mmap = v9fs_file_mmap,
658 .fsync = v9fs_file_fsync_dotl,
659 };
660
661 const struct file_operations v9fs_file_operations = {
662 .llseek = generic_file_llseek,
663 .read_iter = v9fs_file_read_iter,
664 .write_iter = v9fs_file_write_iter,
665 .open = v9fs_file_open,
666 .release = v9fs_dir_release,
667 .lock = v9fs_file_lock,
668 .mmap = generic_file_readonly_mmap,
669 .fsync = v9fs_file_fsync,
670 };
671
672 const struct file_operations v9fs_file_operations_dotl = {
673 .llseek = generic_file_llseek,
674 .read_iter = v9fs_file_read_iter,
675 .write_iter = v9fs_file_write_iter,
676 .open = v9fs_file_open,
677 .release = v9fs_dir_release,
678 .lock = v9fs_file_lock_dotl,
679 .flock = v9fs_file_flock_dotl,
680 .mmap = generic_file_readonly_mmap,
681 .fsync = v9fs_file_fsync_dotl,
682 };
683
684 const struct file_operations v9fs_mmap_file_operations = {
685 .llseek = generic_file_llseek,
686 .read_iter = v9fs_mmap_file_read_iter,
687 .write_iter = v9fs_mmap_file_write_iter,
688 .open = v9fs_file_open,
689 .release = v9fs_dir_release,
690 .lock = v9fs_file_lock,
691 .mmap = v9fs_mmap_file_mmap,
692 .fsync = v9fs_file_fsync,
693 };
694
695 const struct file_operations v9fs_mmap_file_operations_dotl = {
696 .llseek = generic_file_llseek,
697 .read_iter = v9fs_mmap_file_read_iter,
698 .write_iter = v9fs_mmap_file_write_iter,
699 .open = v9fs_file_open,
700 .release = v9fs_dir_release,
701 .lock = v9fs_file_lock_dotl,
702 .flock = v9fs_file_flock_dotl,
703 .mmap = v9fs_mmap_file_mmap,
704 .fsync = v9fs_file_fsync_dotl,
705 };
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