Merge tag 'kvm-arm-fixes-4.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git...
[deliverable/linux.git] / fs / 9p / v9fs.c
1 /*
2 * linux/fs/9p/v9fs.c
3 *
4 * This file contains functions assisting in mapping VFS to 9P2000
5 *
6 * Copyright (C) 2004-2008 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27
28 #include <linux/module.h>
29 #include <linux/errno.h>
30 #include <linux/fs.h>
31 #include <linux/sched.h>
32 #include <linux/parser.h>
33 #include <linux/idr.h>
34 #include <linux/slab.h>
35 #include <net/9p/9p.h>
36 #include <net/9p/client.h>
37 #include <net/9p/transport.h>
38 #include "v9fs.h"
39 #include "v9fs_vfs.h"
40 #include "cache.h"
41
42 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
43 static LIST_HEAD(v9fs_sessionlist);
44 struct kmem_cache *v9fs_inode_cache;
45
46 /*
47 * Option Parsing (code inspired by NFS code)
48 * NOTE: each transport will parse its own options
49 */
50
51 enum {
52 /* Options that take integer arguments */
53 Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
54 /* String options */
55 Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
56 /* Options that take no arguments */
57 Opt_nodevmap,
58 /* Cache options */
59 Opt_cache_loose, Opt_fscache, Opt_mmap,
60 /* Access options */
61 Opt_access, Opt_posixacl,
62 /* Error token */
63 Opt_err
64 };
65
66 static const match_table_t tokens = {
67 {Opt_debug, "debug=%x"},
68 {Opt_dfltuid, "dfltuid=%u"},
69 {Opt_dfltgid, "dfltgid=%u"},
70 {Opt_afid, "afid=%u"},
71 {Opt_uname, "uname=%s"},
72 {Opt_remotename, "aname=%s"},
73 {Opt_nodevmap, "nodevmap"},
74 {Opt_cache, "cache=%s"},
75 {Opt_cache_loose, "loose"},
76 {Opt_fscache, "fscache"},
77 {Opt_mmap, "mmap"},
78 {Opt_cachetag, "cachetag=%s"},
79 {Opt_access, "access=%s"},
80 {Opt_posixacl, "posixacl"},
81 {Opt_err, NULL}
82 };
83
84 /* Interpret mount options for cache mode */
85 static int get_cache_mode(char *s)
86 {
87 int version = -EINVAL;
88
89 if (!strcmp(s, "loose")) {
90 version = CACHE_LOOSE;
91 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
92 } else if (!strcmp(s, "fscache")) {
93 version = CACHE_FSCACHE;
94 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
95 } else if (!strcmp(s, "mmap")) {
96 version = CACHE_MMAP;
97 p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
98 } else if (!strcmp(s, "none")) {
99 version = CACHE_NONE;
100 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
101 } else
102 pr_info("Unknown Cache mode %s\n", s);
103 return version;
104 }
105
106 /**
107 * v9fs_parse_options - parse mount options into session structure
108 * @v9ses: existing v9fs session information
109 *
110 * Return 0 upon success, -ERRNO upon failure.
111 */
112
113 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
114 {
115 char *options, *tmp_options;
116 substring_t args[MAX_OPT_ARGS];
117 char *p;
118 int option = 0;
119 char *s, *e;
120 int ret = 0;
121
122 /* setup defaults */
123 v9ses->afid = ~0;
124 v9ses->debug = 0;
125 v9ses->cache = CACHE_NONE;
126 #ifdef CONFIG_9P_FSCACHE
127 v9ses->cachetag = NULL;
128 #endif
129
130 if (!opts)
131 return 0;
132
133 tmp_options = kstrdup(opts, GFP_KERNEL);
134 if (!tmp_options) {
135 ret = -ENOMEM;
136 goto fail_option_alloc;
137 }
138 options = tmp_options;
139
140 while ((p = strsep(&options, ",")) != NULL) {
141 int token, r;
142 if (!*p)
143 continue;
144 token = match_token(p, tokens, args);
145 switch (token) {
146 case Opt_debug:
147 r = match_int(&args[0], &option);
148 if (r < 0) {
149 p9_debug(P9_DEBUG_ERROR,
150 "integer field, but no integer?\n");
151 ret = r;
152 continue;
153 }
154 v9ses->debug = option;
155 #ifdef CONFIG_NET_9P_DEBUG
156 p9_debug_level = option;
157 #endif
158 break;
159
160 case Opt_dfltuid:
161 r = match_int(&args[0], &option);
162 if (r < 0) {
163 p9_debug(P9_DEBUG_ERROR,
164 "integer field, but no integer?\n");
165 ret = r;
166 continue;
167 }
168 v9ses->dfltuid = make_kuid(current_user_ns(), option);
169 if (!uid_valid(v9ses->dfltuid)) {
170 p9_debug(P9_DEBUG_ERROR,
171 "uid field, but not a uid?\n");
172 ret = -EINVAL;
173 continue;
174 }
175 break;
176 case Opt_dfltgid:
177 r = match_int(&args[0], &option);
178 if (r < 0) {
179 p9_debug(P9_DEBUG_ERROR,
180 "integer field, but no integer?\n");
181 ret = r;
182 continue;
183 }
184 v9ses->dfltgid = make_kgid(current_user_ns(), option);
185 if (!gid_valid(v9ses->dfltgid)) {
186 p9_debug(P9_DEBUG_ERROR,
187 "gid field, but not a gid?\n");
188 ret = -EINVAL;
189 continue;
190 }
191 break;
192 case Opt_afid:
193 r = match_int(&args[0], &option);
194 if (r < 0) {
195 p9_debug(P9_DEBUG_ERROR,
196 "integer field, but no integer?\n");
197 ret = r;
198 continue;
199 }
200 v9ses->afid = option;
201 break;
202 case Opt_uname:
203 kfree(v9ses->uname);
204 v9ses->uname = match_strdup(&args[0]);
205 if (!v9ses->uname) {
206 ret = -ENOMEM;
207 goto free_and_return;
208 }
209 break;
210 case Opt_remotename:
211 kfree(v9ses->aname);
212 v9ses->aname = match_strdup(&args[0]);
213 if (!v9ses->aname) {
214 ret = -ENOMEM;
215 goto free_and_return;
216 }
217 break;
218 case Opt_nodevmap:
219 v9ses->nodev = 1;
220 break;
221 case Opt_cache_loose:
222 v9ses->cache = CACHE_LOOSE;
223 break;
224 case Opt_fscache:
225 v9ses->cache = CACHE_FSCACHE;
226 break;
227 case Opt_mmap:
228 v9ses->cache = CACHE_MMAP;
229 break;
230 case Opt_cachetag:
231 #ifdef CONFIG_9P_FSCACHE
232 v9ses->cachetag = match_strdup(&args[0]);
233 #endif
234 break;
235 case Opt_cache:
236 s = match_strdup(&args[0]);
237 if (!s) {
238 ret = -ENOMEM;
239 p9_debug(P9_DEBUG_ERROR,
240 "problem allocating copy of cache arg\n");
241 goto free_and_return;
242 }
243 ret = get_cache_mode(s);
244 if (ret == -EINVAL) {
245 kfree(s);
246 goto free_and_return;
247 }
248
249 v9ses->cache = ret;
250 kfree(s);
251 break;
252
253 case Opt_access:
254 s = match_strdup(&args[0]);
255 if (!s) {
256 ret = -ENOMEM;
257 p9_debug(P9_DEBUG_ERROR,
258 "problem allocating copy of access arg\n");
259 goto free_and_return;
260 }
261
262 v9ses->flags &= ~V9FS_ACCESS_MASK;
263 if (strcmp(s, "user") == 0)
264 v9ses->flags |= V9FS_ACCESS_USER;
265 else if (strcmp(s, "any") == 0)
266 v9ses->flags |= V9FS_ACCESS_ANY;
267 else if (strcmp(s, "client") == 0) {
268 v9ses->flags |= V9FS_ACCESS_CLIENT;
269 } else {
270 uid_t uid;
271 v9ses->flags |= V9FS_ACCESS_SINGLE;
272 uid = simple_strtoul(s, &e, 10);
273 if (*e != '\0') {
274 ret = -EINVAL;
275 pr_info("Unknown access argument %s\n",
276 s);
277 kfree(s);
278 goto free_and_return;
279 }
280 v9ses->uid = make_kuid(current_user_ns(), uid);
281 if (!uid_valid(v9ses->uid)) {
282 ret = -EINVAL;
283 pr_info("Uknown uid %s\n", s);
284 kfree(s);
285 goto free_and_return;
286 }
287 }
288
289 kfree(s);
290 break;
291
292 case Opt_posixacl:
293 #ifdef CONFIG_9P_FS_POSIX_ACL
294 v9ses->flags |= V9FS_POSIX_ACL;
295 #else
296 p9_debug(P9_DEBUG_ERROR,
297 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
298 #endif
299 break;
300
301 default:
302 continue;
303 }
304 }
305
306 free_and_return:
307 kfree(tmp_options);
308 fail_option_alloc:
309 return ret;
310 }
311
312 /**
313 * v9fs_session_init - initialize session
314 * @v9ses: session information structure
315 * @dev_name: device being mounted
316 * @data: options
317 *
318 */
319
320 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
321 const char *dev_name, char *data)
322 {
323 int retval = -EINVAL;
324 struct p9_fid *fid;
325 int rc;
326
327 v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
328 if (!v9ses->uname)
329 return ERR_PTR(-ENOMEM);
330
331 v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
332 if (!v9ses->aname) {
333 kfree(v9ses->uname);
334 return ERR_PTR(-ENOMEM);
335 }
336 init_rwsem(&v9ses->rename_sem);
337
338 rc = bdi_setup_and_register(&v9ses->bdi, "9p");
339 if (rc) {
340 kfree(v9ses->aname);
341 kfree(v9ses->uname);
342 return ERR_PTR(rc);
343 }
344
345 spin_lock(&v9fs_sessionlist_lock);
346 list_add(&v9ses->slist, &v9fs_sessionlist);
347 spin_unlock(&v9fs_sessionlist_lock);
348
349 v9ses->uid = INVALID_UID;
350 v9ses->dfltuid = V9FS_DEFUID;
351 v9ses->dfltgid = V9FS_DEFGID;
352
353 v9ses->clnt = p9_client_create(dev_name, data);
354 if (IS_ERR(v9ses->clnt)) {
355 retval = PTR_ERR(v9ses->clnt);
356 v9ses->clnt = NULL;
357 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
358 goto error;
359 }
360
361 v9ses->flags = V9FS_ACCESS_USER;
362
363 if (p9_is_proto_dotl(v9ses->clnt)) {
364 v9ses->flags = V9FS_ACCESS_CLIENT;
365 v9ses->flags |= V9FS_PROTO_2000L;
366 } else if (p9_is_proto_dotu(v9ses->clnt)) {
367 v9ses->flags |= V9FS_PROTO_2000U;
368 }
369
370 rc = v9fs_parse_options(v9ses, data);
371 if (rc < 0) {
372 retval = rc;
373 goto error;
374 }
375
376 v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
377
378 if (!v9fs_proto_dotl(v9ses) &&
379 ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
380 /*
381 * We support ACCESS_CLIENT only for dotl.
382 * Fall back to ACCESS_USER
383 */
384 v9ses->flags &= ~V9FS_ACCESS_MASK;
385 v9ses->flags |= V9FS_ACCESS_USER;
386 }
387 /*FIXME !! */
388 /* for legacy mode, fall back to V9FS_ACCESS_ANY */
389 if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
390 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
391
392 v9ses->flags &= ~V9FS_ACCESS_MASK;
393 v9ses->flags |= V9FS_ACCESS_ANY;
394 v9ses->uid = INVALID_UID;
395 }
396 if (!v9fs_proto_dotl(v9ses) ||
397 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
398 /*
399 * We support ACL checks on clinet only if the protocol is
400 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
401 */
402 v9ses->flags &= ~V9FS_ACL_MASK;
403 }
404
405 fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
406 v9ses->aname);
407 if (IS_ERR(fid)) {
408 retval = PTR_ERR(fid);
409 fid = NULL;
410 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
411 goto error;
412 }
413
414 if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
415 fid->uid = v9ses->uid;
416 else
417 fid->uid = INVALID_UID;
418
419 #ifdef CONFIG_9P_FSCACHE
420 /* register the session for caching */
421 v9fs_cache_session_get_cookie(v9ses);
422 #endif
423
424 return fid;
425
426 error:
427 bdi_destroy(&v9ses->bdi);
428 return ERR_PTR(retval);
429 }
430
431 /**
432 * v9fs_session_close - shutdown a session
433 * @v9ses: session information structure
434 *
435 */
436
437 void v9fs_session_close(struct v9fs_session_info *v9ses)
438 {
439 if (v9ses->clnt) {
440 p9_client_destroy(v9ses->clnt);
441 v9ses->clnt = NULL;
442 }
443
444 #ifdef CONFIG_9P_FSCACHE
445 if (v9ses->fscache) {
446 v9fs_cache_session_put_cookie(v9ses);
447 kfree(v9ses->cachetag);
448 }
449 #endif
450 kfree(v9ses->uname);
451 kfree(v9ses->aname);
452
453 bdi_destroy(&v9ses->bdi);
454
455 spin_lock(&v9fs_sessionlist_lock);
456 list_del(&v9ses->slist);
457 spin_unlock(&v9fs_sessionlist_lock);
458 }
459
460 /**
461 * v9fs_session_cancel - terminate a session
462 * @v9ses: session to terminate
463 *
464 * mark transport as disconnected and cancel all pending requests.
465 */
466
467 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
468 p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
469 p9_client_disconnect(v9ses->clnt);
470 }
471
472 /**
473 * v9fs_session_begin_cancel - Begin terminate of a session
474 * @v9ses: session to terminate
475 *
476 * After this call we don't allow any request other than clunk.
477 */
478
479 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
480 {
481 p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
482 p9_client_begin_disconnect(v9ses->clnt);
483 }
484
485 extern int v9fs_error_init(void);
486
487 static struct kobject *v9fs_kobj;
488
489 #ifdef CONFIG_9P_FSCACHE
490 /**
491 * caches_show - list caches associated with a session
492 *
493 * Returns the size of buffer written.
494 */
495
496 static ssize_t caches_show(struct kobject *kobj,
497 struct kobj_attribute *attr,
498 char *buf)
499 {
500 ssize_t n = 0, count = 0, limit = PAGE_SIZE;
501 struct v9fs_session_info *v9ses;
502
503 spin_lock(&v9fs_sessionlist_lock);
504 list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
505 if (v9ses->cachetag) {
506 n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
507 if (n < 0) {
508 count = n;
509 break;
510 }
511
512 count += n;
513 limit -= n;
514 }
515 }
516
517 spin_unlock(&v9fs_sessionlist_lock);
518 return count;
519 }
520
521 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
522 #endif /* CONFIG_9P_FSCACHE */
523
524 static struct attribute *v9fs_attrs[] = {
525 #ifdef CONFIG_9P_FSCACHE
526 &v9fs_attr_cache.attr,
527 #endif
528 NULL,
529 };
530
531 static struct attribute_group v9fs_attr_group = {
532 .attrs = v9fs_attrs,
533 };
534
535 /**
536 * v9fs_sysfs_init - Initialize the v9fs sysfs interface
537 *
538 */
539
540 static int __init v9fs_sysfs_init(void)
541 {
542 v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
543 if (!v9fs_kobj)
544 return -ENOMEM;
545
546 if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
547 kobject_put(v9fs_kobj);
548 return -ENOMEM;
549 }
550
551 return 0;
552 }
553
554 /**
555 * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
556 *
557 */
558
559 static void v9fs_sysfs_cleanup(void)
560 {
561 sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
562 kobject_put(v9fs_kobj);
563 }
564
565 static void v9fs_inode_init_once(void *foo)
566 {
567 struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
568 #ifdef CONFIG_9P_FSCACHE
569 v9inode->fscache = NULL;
570 #endif
571 memset(&v9inode->qid, 0, sizeof(v9inode->qid));
572 inode_init_once(&v9inode->vfs_inode);
573 }
574
575 /**
576 * v9fs_init_inode_cache - initialize a cache for 9P
577 * Returns 0 on success.
578 */
579 static int v9fs_init_inode_cache(void)
580 {
581 v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
582 sizeof(struct v9fs_inode),
583 0, (SLAB_RECLAIM_ACCOUNT|
584 SLAB_MEM_SPREAD),
585 v9fs_inode_init_once);
586 if (!v9fs_inode_cache)
587 return -ENOMEM;
588
589 return 0;
590 }
591
592 /**
593 * v9fs_destroy_inode_cache - destroy the cache of 9P inode
594 *
595 */
596 static void v9fs_destroy_inode_cache(void)
597 {
598 /*
599 * Make sure all delayed rcu free inodes are flushed before we
600 * destroy cache.
601 */
602 rcu_barrier();
603 kmem_cache_destroy(v9fs_inode_cache);
604 }
605
606 static int v9fs_cache_register(void)
607 {
608 int ret;
609 ret = v9fs_init_inode_cache();
610 if (ret < 0)
611 return ret;
612 #ifdef CONFIG_9P_FSCACHE
613 ret = fscache_register_netfs(&v9fs_cache_netfs);
614 if (ret < 0)
615 v9fs_destroy_inode_cache();
616 #endif
617 return ret;
618 }
619
620 static void v9fs_cache_unregister(void)
621 {
622 v9fs_destroy_inode_cache();
623 #ifdef CONFIG_9P_FSCACHE
624 fscache_unregister_netfs(&v9fs_cache_netfs);
625 #endif
626 }
627
628 /**
629 * init_v9fs - Initialize module
630 *
631 */
632
633 static int __init init_v9fs(void)
634 {
635 int err;
636 pr_info("Installing v9fs 9p2000 file system support\n");
637 /* TODO: Setup list of registered trasnport modules */
638
639 err = v9fs_cache_register();
640 if (err < 0) {
641 pr_err("Failed to register v9fs for caching\n");
642 return err;
643 }
644
645 err = v9fs_sysfs_init();
646 if (err < 0) {
647 pr_err("Failed to register with sysfs\n");
648 goto out_cache;
649 }
650 err = register_filesystem(&v9fs_fs_type);
651 if (err < 0) {
652 pr_err("Failed to register filesystem\n");
653 goto out_sysfs_cleanup;
654 }
655
656 return 0;
657
658 out_sysfs_cleanup:
659 v9fs_sysfs_cleanup();
660
661 out_cache:
662 v9fs_cache_unregister();
663
664 return err;
665 }
666
667 /**
668 * exit_v9fs - shutdown module
669 *
670 */
671
672 static void __exit exit_v9fs(void)
673 {
674 v9fs_sysfs_cleanup();
675 v9fs_cache_unregister();
676 unregister_filesystem(&v9fs_fs_type);
677 }
678
679 module_init(init_v9fs)
680 module_exit(exit_v9fs)
681
682 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
683 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
684 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
685 MODULE_LICENSE("GPL");
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