fs/9p: Fix invalid mount options/args
[linux-2.6.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 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/fs.h>
29 #include <linux/sched.h>
30 #include <linux/parser.h>
31 #include <linux/idr.h>
32 #include <linux/slab.h>
33 #include <net/9p/9p.h>
34 #include <net/9p/client.h>
35 #include <net/9p/transport.h>
36 #include "v9fs.h"
37 #include "v9fs_vfs.h"
38 #include "cache.h"
39
40 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
41 static LIST_HEAD(v9fs_sessionlist);
42 struct kmem_cache *v9fs_inode_cache;
43
44 /*
45  * Option Parsing (code inspired by NFS code)
46  *  NOTE: each transport will parse its own options
47  */
48
49 enum {
50         /* Options that take integer arguments */
51         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
52         /* String options */
53         Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
54         /* Options that take no arguments */
55         Opt_nodevmap,
56         /* Cache options */
57         Opt_cache_loose, Opt_fscache,
58         /* Access options */
59         Opt_access, Opt_posixacl,
60         /* Error token */
61         Opt_err
62 };
63
64 static const match_table_t tokens = {
65         {Opt_debug, "debug=%x"},
66         {Opt_dfltuid, "dfltuid=%u"},
67         {Opt_dfltgid, "dfltgid=%u"},
68         {Opt_afid, "afid=%u"},
69         {Opt_uname, "uname=%s"},
70         {Opt_remotename, "aname=%s"},
71         {Opt_nodevmap, "nodevmap"},
72         {Opt_cache, "cache=%s"},
73         {Opt_cache_loose, "loose"},
74         {Opt_fscache, "fscache"},
75         {Opt_cachetag, "cachetag=%s"},
76         {Opt_access, "access=%s"},
77         {Opt_posixacl, "posixacl"},
78         {Opt_err, NULL}
79 };
80
81 /* Interpret mount options for cache mode */
82 static int get_cache_mode(char *s)
83 {
84         int version = -EINVAL;
85
86         if (!strcmp(s, "loose")) {
87                 version = CACHE_LOOSE;
88                 P9_DPRINTK(P9_DEBUG_9P, "Cache mode: loose\n");
89         } else if (!strcmp(s, "fscache")) {
90                 version = CACHE_FSCACHE;
91                 P9_DPRINTK(P9_DEBUG_9P, "Cache mode: fscache\n");
92         } else if (!strcmp(s, "none")) {
93                 version = CACHE_NONE;
94                 P9_DPRINTK(P9_DEBUG_9P, "Cache mode: none\n");
95         } else
96                 printk(KERN_INFO "9p: Unknown Cache mode %s.\n", s);
97         return version;
98 }
99
100 /**
101  * v9fs_parse_options - parse mount options into session structure
102  * @v9ses: existing v9fs session information
103  *
104  * Return 0 upon success, -ERRNO upon failure.
105  */
106
107 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
108 {
109         char *options, *tmp_options;
110         substring_t args[MAX_OPT_ARGS];
111         char *p;
112         int option = 0;
113         char *s, *e;
114         int ret = 0;
115
116         /* setup defaults */
117         v9ses->afid = ~0;
118         v9ses->debug = 0;
119         v9ses->cache = CACHE_NONE;
120 #ifdef CONFIG_9P_FSCACHE
121         v9ses->cachetag = NULL;
122 #endif
123
124         if (!opts)
125                 return 0;
126
127         tmp_options = kstrdup(opts, GFP_KERNEL);
128         if (!tmp_options) {
129                 ret = -ENOMEM;
130                 goto fail_option_alloc;
131         }
132         options = tmp_options;
133
134         while ((p = strsep(&options, ",")) != NULL) {
135                 int token;
136                 if (!*p)
137                         continue;
138                 token = match_token(p, tokens, args);
139                 if (token < Opt_uname) {
140                         int r = match_int(&args[0], &option);
141                         if (r < 0) {
142                                 P9_DPRINTK(P9_DEBUG_ERROR,
143                                         "integer field, but no integer?\n");
144                                 ret = r;
145                                 continue;
146                         }
147                 }
148                 switch (token) {
149                 case Opt_debug:
150                         v9ses->debug = option;
151 #ifdef CONFIG_NET_9P_DEBUG
152                         p9_debug_level = option;
153 #endif
154                         break;
155
156                 case Opt_dfltuid:
157                         v9ses->dfltuid = option;
158                         break;
159                 case Opt_dfltgid:
160                         v9ses->dfltgid = option;
161                         break;
162                 case Opt_afid:
163                         v9ses->afid = option;
164                         break;
165                 case Opt_uname:
166                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
167                         break;
168                 case Opt_remotename:
169                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
170                         break;
171                 case Opt_nodevmap:
172                         v9ses->nodev = 1;
173                         break;
174                 case Opt_cache_loose:
175                         v9ses->cache = CACHE_LOOSE;
176                         break;
177                 case Opt_fscache:
178                         v9ses->cache = CACHE_FSCACHE;
179                         break;
180                 case Opt_cachetag:
181 #ifdef CONFIG_9P_FSCACHE
182                         v9ses->cachetag = match_strdup(&args[0]);
183 #endif
184                         break;
185                 case Opt_cache:
186                         s = match_strdup(&args[0]);
187                         if (!s) {
188                                 ret = -ENOMEM;
189                                 P9_DPRINTK(P9_DEBUG_ERROR,
190                                   "problem allocating copy of cache arg\n");
191                                 goto free_and_return;
192                         }
193                         ret = get_cache_mode(s);
194                         if (ret == -EINVAL) {
195                                 kfree(s);
196                                 goto free_and_return;
197                         }
198
199                         v9ses->cache = ret;
200                         kfree(s);
201                         break;
202
203                 case Opt_access:
204                         s = match_strdup(&args[0]);
205                         if (!s) {
206                                 ret = -ENOMEM;
207                                 P9_DPRINTK(P9_DEBUG_ERROR,
208                                   "problem allocating copy of access arg\n");
209                                 goto free_and_return;
210                         }
211
212                         v9ses->flags &= ~V9FS_ACCESS_MASK;
213                         if (strcmp(s, "user") == 0)
214                                 v9ses->flags |= V9FS_ACCESS_USER;
215                         else if (strcmp(s, "any") == 0)
216                                 v9ses->flags |= V9FS_ACCESS_ANY;
217                         else if (strcmp(s, "client") == 0) {
218                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
219                         } else {
220                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
221                                 v9ses->uid = simple_strtoul(s, &e, 10);
222                                 if (*e != '\0') {
223                                         ret = -EINVAL;
224                                         printk(KERN_INFO "9p: Unknown access "
225                                                         "argument %s.\n", s);
226                                         kfree(s);
227                                         goto free_and_return;
228                                 }
229                         }
230
231                         kfree(s);
232                         break;
233
234                 case Opt_posixacl:
235 #ifdef CONFIG_9P_FS_POSIX_ACL
236                         v9ses->flags |= V9FS_POSIX_ACL;
237 #else
238                         P9_DPRINTK(P9_DEBUG_ERROR,
239                                         "Not defined CONFIG_9P_FS_POSIX_ACL. "
240                                         "Ignoring posixacl option\n");
241 #endif
242                         break;
243
244                 default:
245                         continue;
246                 }
247         }
248
249 free_and_return:
250         kfree(tmp_options);
251 fail_option_alloc:
252         return ret;
253 }
254
255 /**
256  * v9fs_session_init - initialize session
257  * @v9ses: session information structure
258  * @dev_name: device being mounted
259  * @data: options
260  *
261  */
262
263 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
264                   const char *dev_name, char *data)
265 {
266         int retval = -EINVAL;
267         struct p9_fid *fid;
268         int rc;
269
270         v9ses->uname = __getname();
271         if (!v9ses->uname)
272                 return ERR_PTR(-ENOMEM);
273
274         v9ses->aname = __getname();
275         if (!v9ses->aname) {
276                 __putname(v9ses->uname);
277                 return ERR_PTR(-ENOMEM);
278         }
279         init_rwsem(&v9ses->rename_sem);
280
281         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
282         if (rc) {
283                 __putname(v9ses->aname);
284                 __putname(v9ses->uname);
285                 return ERR_PTR(rc);
286         }
287
288         spin_lock(&v9fs_sessionlist_lock);
289         list_add(&v9ses->slist, &v9fs_sessionlist);
290         spin_unlock(&v9fs_sessionlist_lock);
291
292         strcpy(v9ses->uname, V9FS_DEFUSER);
293         strcpy(v9ses->aname, V9FS_DEFANAME);
294         v9ses->uid = ~0;
295         v9ses->dfltuid = V9FS_DEFUID;
296         v9ses->dfltgid = V9FS_DEFGID;
297
298         v9ses->clnt = p9_client_create(dev_name, data);
299         if (IS_ERR(v9ses->clnt)) {
300                 retval = PTR_ERR(v9ses->clnt);
301                 v9ses->clnt = NULL;
302                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
303                 goto error;
304         }
305
306         v9ses->flags = V9FS_ACCESS_USER;
307
308         if (p9_is_proto_dotl(v9ses->clnt)) {
309                 v9ses->flags = V9FS_ACCESS_CLIENT;
310                 v9ses->flags |= V9FS_PROTO_2000L;
311         } else if (p9_is_proto_dotu(v9ses->clnt)) {
312                 v9ses->flags |= V9FS_PROTO_2000U;
313         }
314
315         rc = v9fs_parse_options(v9ses, data);
316         if (rc < 0) {
317                 retval = rc;
318                 goto error;
319         }
320
321         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
322
323         if (!v9fs_proto_dotl(v9ses) &&
324             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
325                 /*
326                  * We support ACCESS_CLIENT only for dotl.
327                  * Fall back to ACCESS_USER
328                  */
329                 v9ses->flags &= ~V9FS_ACCESS_MASK;
330                 v9ses->flags |= V9FS_ACCESS_USER;
331         }
332         /*FIXME !! */
333         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
334         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
335                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
336
337                 v9ses->flags &= ~V9FS_ACCESS_MASK;
338                 v9ses->flags |= V9FS_ACCESS_ANY;
339                 v9ses->uid = ~0;
340         }
341         if (!v9fs_proto_dotl(v9ses) ||
342                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
343                 /*
344                  * We support ACL checks on clinet only if the protocol is
345                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
346                  */
347                 v9ses->flags &= ~V9FS_ACL_MASK;
348         }
349
350         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
351                                                         v9ses->aname);
352         if (IS_ERR(fid)) {
353                 retval = PTR_ERR(fid);
354                 fid = NULL;
355                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
356                 goto error;
357         }
358
359         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
360                 fid->uid = v9ses->uid;
361         else
362                 fid->uid = ~0;
363
364 #ifdef CONFIG_9P_FSCACHE
365         /* register the session for caching */
366         v9fs_cache_session_get_cookie(v9ses);
367 #endif
368
369         return fid;
370
371 error:
372         bdi_destroy(&v9ses->bdi);
373         return ERR_PTR(retval);
374 }
375
376 /**
377  * v9fs_session_close - shutdown a session
378  * @v9ses: session information structure
379  *
380  */
381
382 void v9fs_session_close(struct v9fs_session_info *v9ses)
383 {
384         if (v9ses->clnt) {
385                 p9_client_destroy(v9ses->clnt);
386                 v9ses->clnt = NULL;
387         }
388
389 #ifdef CONFIG_9P_FSCACHE
390         if (v9ses->fscache) {
391                 v9fs_cache_session_put_cookie(v9ses);
392                 kfree(v9ses->cachetag);
393         }
394 #endif
395         __putname(v9ses->uname);
396         __putname(v9ses->aname);
397
398         bdi_destroy(&v9ses->bdi);
399
400         spin_lock(&v9fs_sessionlist_lock);
401         list_del(&v9ses->slist);
402         spin_unlock(&v9fs_sessionlist_lock);
403 }
404
405 /**
406  * v9fs_session_cancel - terminate a session
407  * @v9ses: session to terminate
408  *
409  * mark transport as disconnected and cancel all pending requests.
410  */
411
412 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
413         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
414         p9_client_disconnect(v9ses->clnt);
415 }
416
417 /**
418  * v9fs_session_begin_cancel - Begin terminate of a session
419  * @v9ses: session to terminate
420  *
421  * After this call we don't allow any request other than clunk.
422  */
423
424 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
425 {
426         P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
427         p9_client_begin_disconnect(v9ses->clnt);
428 }
429
430 extern int v9fs_error_init(void);
431
432 static struct kobject *v9fs_kobj;
433
434 #ifdef CONFIG_9P_FSCACHE
435 /**
436  * caches_show - list caches associated with a session
437  *
438  * Returns the size of buffer written.
439  */
440
441 static ssize_t caches_show(struct kobject *kobj,
442                            struct kobj_attribute *attr,
443                            char *buf)
444 {
445         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
446         struct v9fs_session_info *v9ses;
447
448         spin_lock(&v9fs_sessionlist_lock);
449         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
450                 if (v9ses->cachetag) {
451                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
452                         if (n < 0) {
453                                 count = n;
454                                 break;
455                         }
456
457                         count += n;
458                         limit -= n;
459                 }
460         }
461
462         spin_unlock(&v9fs_sessionlist_lock);
463         return count;
464 }
465
466 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
467 #endif /* CONFIG_9P_FSCACHE */
468
469 static struct attribute *v9fs_attrs[] = {
470 #ifdef CONFIG_9P_FSCACHE
471         &v9fs_attr_cache.attr,
472 #endif
473         NULL,
474 };
475
476 static struct attribute_group v9fs_attr_group = {
477         .attrs = v9fs_attrs,
478 };
479
480 /**
481  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
482  *
483  */
484
485 static int v9fs_sysfs_init(void)
486 {
487         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
488         if (!v9fs_kobj)
489                 return -ENOMEM;
490
491         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
492                 kobject_put(v9fs_kobj);
493                 return -ENOMEM;
494         }
495
496         return 0;
497 }
498
499 /**
500  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
501  *
502  */
503
504 static void v9fs_sysfs_cleanup(void)
505 {
506         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
507         kobject_put(v9fs_kobj);
508 }
509
510 static void v9fs_inode_init_once(void *foo)
511 {
512         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
513 #ifdef CONFIG_9P_FSCACHE
514         v9inode->fscache = NULL;
515 #endif
516         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
517         inode_init_once(&v9inode->vfs_inode);
518 }
519
520 /**
521  * v9fs_init_inode_cache - initialize a cache for 9P
522  * Returns 0 on success.
523  */
524 static int v9fs_init_inode_cache(void)
525 {
526         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
527                                           sizeof(struct v9fs_inode),
528                                           0, (SLAB_RECLAIM_ACCOUNT|
529                                               SLAB_MEM_SPREAD),
530                                           v9fs_inode_init_once);
531         if (!v9fs_inode_cache)
532                 return -ENOMEM;
533
534         return 0;
535 }
536
537 /**
538  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
539  *
540  */
541 static void v9fs_destroy_inode_cache(void)
542 {
543         kmem_cache_destroy(v9fs_inode_cache);
544 }
545
546 static int v9fs_cache_register(void)
547 {
548         int ret;
549         ret = v9fs_init_inode_cache();
550         if (ret < 0)
551                 return ret;
552 #ifdef CONFIG_9P_FSCACHE
553         return fscache_register_netfs(&v9fs_cache_netfs);
554 #else
555         return ret;
556 #endif
557 }
558
559 static void v9fs_cache_unregister(void)
560 {
561         v9fs_destroy_inode_cache();
562 #ifdef CONFIG_9P_FSCACHE
563         fscache_unregister_netfs(&v9fs_cache_netfs);
564 #endif
565 }
566
567 /**
568  * init_v9fs - Initialize module
569  *
570  */
571
572 static int __init init_v9fs(void)
573 {
574         int err;
575         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
576         /* TODO: Setup list of registered trasnport modules */
577         err = register_filesystem(&v9fs_fs_type);
578         if (err < 0) {
579                 printk(KERN_ERR "Failed to register filesystem\n");
580                 return err;
581         }
582
583         err = v9fs_cache_register();
584         if (err < 0) {
585                 printk(KERN_ERR "Failed to register v9fs for caching\n");
586                 goto out_fs_unreg;
587         }
588
589         err = v9fs_sysfs_init();
590         if (err < 0) {
591                 printk(KERN_ERR "Failed to register with sysfs\n");
592                 goto out_sysfs_cleanup;
593         }
594
595         return 0;
596
597 out_sysfs_cleanup:
598         v9fs_sysfs_cleanup();
599
600 out_fs_unreg:
601         unregister_filesystem(&v9fs_fs_type);
602
603         return err;
604 }
605
606 /**
607  * exit_v9fs - shutdown module
608  *
609  */
610
611 static void __exit exit_v9fs(void)
612 {
613         v9fs_sysfs_cleanup();
614         v9fs_cache_unregister();
615         unregister_filesystem(&v9fs_fs_type);
616 }
617
618 module_init(init_v9fs)
619 module_exit(exit_v9fs)
620
621 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
622 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
623 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
624 MODULE_LICENSE("GPL");