8b7c6be2450b0fe2156ac5dfe56fd56884444180
[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 /**
82  * v9fs_parse_options - parse mount options into session structure
83  * @v9ses: existing v9fs session information
84  *
85  * Return 0 upon success, -ERRNO upon failure.
86  */
87
88 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
89 {
90         char *options, *tmp_options;
91         substring_t args[MAX_OPT_ARGS];
92         char *p;
93         int option = 0;
94         char *s, *e;
95         int ret = 0;
96
97         /* setup defaults */
98         v9ses->afid = ~0;
99         v9ses->debug = 0;
100         v9ses->cache = 0;
101 #ifdef CONFIG_9P_FSCACHE
102         v9ses->cachetag = NULL;
103 #endif
104
105         if (!opts)
106                 return 0;
107
108         tmp_options = kstrdup(opts, GFP_KERNEL);
109         if (!tmp_options) {
110                 ret = -ENOMEM;
111                 goto fail_option_alloc;
112         }
113         options = tmp_options;
114
115         while ((p = strsep(&options, ",")) != NULL) {
116                 int token;
117                 if (!*p)
118                         continue;
119                 token = match_token(p, tokens, args);
120                 if (token < Opt_uname) {
121                         int r = match_int(&args[0], &option);
122                         if (r < 0) {
123                                 P9_DPRINTK(P9_DEBUG_ERROR,
124                                         "integer field, but no integer?\n");
125                                 ret = r;
126                                 continue;
127                         }
128                 }
129                 switch (token) {
130                 case Opt_debug:
131                         v9ses->debug = option;
132 #ifdef CONFIG_NET_9P_DEBUG
133                         p9_debug_level = option;
134 #endif
135                         break;
136
137                 case Opt_dfltuid:
138                         v9ses->dfltuid = option;
139                         break;
140                 case Opt_dfltgid:
141                         v9ses->dfltgid = option;
142                         break;
143                 case Opt_afid:
144                         v9ses->afid = option;
145                         break;
146                 case Opt_uname:
147                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
148                         break;
149                 case Opt_remotename:
150                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
151                         break;
152                 case Opt_nodevmap:
153                         v9ses->nodev = 1;
154                         break;
155                 case Opt_cache_loose:
156                         v9ses->cache = CACHE_LOOSE;
157                         break;
158                 case Opt_fscache:
159                         v9ses->cache = CACHE_FSCACHE;
160                         break;
161                 case Opt_cachetag:
162 #ifdef CONFIG_9P_FSCACHE
163                         v9ses->cachetag = match_strdup(&args[0]);
164 #endif
165                         break;
166                 case Opt_cache:
167                         s = match_strdup(&args[0]);
168                         if (!s) {
169                                 ret = -ENOMEM;
170                                 P9_DPRINTK(P9_DEBUG_ERROR,
171                                   "problem allocating copy of cache arg\n");
172                                 goto free_and_return;
173                         }
174
175                         if (strcmp(s, "loose") == 0)
176                                 v9ses->cache = CACHE_LOOSE;
177                         else if (strcmp(s, "fscache") == 0)
178                                 v9ses->cache = CACHE_FSCACHE;
179                         else
180                                 v9ses->cache = CACHE_NONE;
181                         kfree(s);
182                         break;
183
184                 case Opt_access:
185                         s = match_strdup(&args[0]);
186                         if (!s) {
187                                 ret = -ENOMEM;
188                                 P9_DPRINTK(P9_DEBUG_ERROR,
189                                   "problem allocating copy of access arg\n");
190                                 goto free_and_return;
191                         }
192
193                         v9ses->flags &= ~V9FS_ACCESS_MASK;
194                         if (strcmp(s, "user") == 0)
195                                 v9ses->flags |= V9FS_ACCESS_USER;
196                         else if (strcmp(s, "any") == 0)
197                                 v9ses->flags |= V9FS_ACCESS_ANY;
198                         else if (strcmp(s, "client") == 0) {
199                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
200                         } else {
201                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
202                                 v9ses->uid = simple_strtoul(s, &e, 10);
203                                 if (*e != '\0')
204                                         v9ses->uid = ~0;
205                         }
206                         kfree(s);
207                         break;
208
209                 case Opt_posixacl:
210 #ifdef CONFIG_9P_FS_POSIX_ACL
211                         v9ses->flags |= V9FS_POSIX_ACL;
212 #else
213                         P9_DPRINTK(P9_DEBUG_ERROR,
214                                         "Not defined CONFIG_9P_FS_POSIX_ACL. "
215                                         "Ignoring posixacl option\n");
216 #endif
217                         break;
218
219                 default:
220                         continue;
221                 }
222         }
223
224 free_and_return:
225         kfree(tmp_options);
226 fail_option_alloc:
227         return ret;
228 }
229
230 /**
231  * v9fs_session_init - initialize session
232  * @v9ses: session information structure
233  * @dev_name: device being mounted
234  * @data: options
235  *
236  */
237
238 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
239                   const char *dev_name, char *data)
240 {
241         int retval = -EINVAL;
242         struct p9_fid *fid;
243         int rc;
244
245         v9ses->uname = __getname();
246         if (!v9ses->uname)
247                 return ERR_PTR(-ENOMEM);
248
249         v9ses->aname = __getname();
250         if (!v9ses->aname) {
251                 __putname(v9ses->uname);
252                 return ERR_PTR(-ENOMEM);
253         }
254         init_rwsem(&v9ses->rename_sem);
255
256         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
257         if (rc) {
258                 __putname(v9ses->aname);
259                 __putname(v9ses->uname);
260                 return ERR_PTR(rc);
261         }
262
263         spin_lock(&v9fs_sessionlist_lock);
264         list_add(&v9ses->slist, &v9fs_sessionlist);
265         spin_unlock(&v9fs_sessionlist_lock);
266
267         strcpy(v9ses->uname, V9FS_DEFUSER);
268         strcpy(v9ses->aname, V9FS_DEFANAME);
269         v9ses->uid = ~0;
270         v9ses->dfltuid = V9FS_DEFUID;
271         v9ses->dfltgid = V9FS_DEFGID;
272
273         v9ses->clnt = p9_client_create(dev_name, data);
274         if (IS_ERR(v9ses->clnt)) {
275                 retval = PTR_ERR(v9ses->clnt);
276                 v9ses->clnt = NULL;
277                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
278                 goto error;
279         }
280
281         v9ses->flags = V9FS_ACCESS_USER;
282
283         if (p9_is_proto_dotl(v9ses->clnt)) {
284                 v9ses->flags = V9FS_ACCESS_CLIENT;
285                 v9ses->flags |= V9FS_PROTO_2000L;
286         } else if (p9_is_proto_dotu(v9ses->clnt)) {
287                 v9ses->flags |= V9FS_PROTO_2000U;
288         }
289
290         rc = v9fs_parse_options(v9ses, data);
291         if (rc < 0) {
292                 retval = rc;
293                 goto error;
294         }
295
296         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
297
298         if (!v9fs_proto_dotl(v9ses) &&
299             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
300                 /*
301                  * We support ACCESS_CLIENT only for dotl.
302                  * Fall back to ACCESS_USER
303                  */
304                 v9ses->flags &= ~V9FS_ACCESS_MASK;
305                 v9ses->flags |= V9FS_ACCESS_USER;
306         }
307         /*FIXME !! */
308         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
309         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
310                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
311
312                 v9ses->flags &= ~V9FS_ACCESS_MASK;
313                 v9ses->flags |= V9FS_ACCESS_ANY;
314                 v9ses->uid = ~0;
315         }
316         if (!v9fs_proto_dotl(v9ses) ||
317                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
318                 /*
319                  * We support ACL checks on clinet only if the protocol is
320                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
321                  */
322                 v9ses->flags &= ~V9FS_ACL_MASK;
323         }
324
325         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
326                                                         v9ses->aname);
327         if (IS_ERR(fid)) {
328                 retval = PTR_ERR(fid);
329                 fid = NULL;
330                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
331                 goto error;
332         }
333
334         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
335                 fid->uid = v9ses->uid;
336         else
337                 fid->uid = ~0;
338
339 #ifdef CONFIG_9P_FSCACHE
340         /* register the session for caching */
341         v9fs_cache_session_get_cookie(v9ses);
342 #endif
343
344         return fid;
345
346 error:
347         bdi_destroy(&v9ses->bdi);
348         return ERR_PTR(retval);
349 }
350
351 /**
352  * v9fs_session_close - shutdown a session
353  * @v9ses: session information structure
354  *
355  */
356
357 void v9fs_session_close(struct v9fs_session_info *v9ses)
358 {
359         if (v9ses->clnt) {
360                 p9_client_destroy(v9ses->clnt);
361                 v9ses->clnt = NULL;
362         }
363
364 #ifdef CONFIG_9P_FSCACHE
365         if (v9ses->fscache) {
366                 v9fs_cache_session_put_cookie(v9ses);
367                 kfree(v9ses->cachetag);
368         }
369 #endif
370         __putname(v9ses->uname);
371         __putname(v9ses->aname);
372
373         bdi_destroy(&v9ses->bdi);
374
375         spin_lock(&v9fs_sessionlist_lock);
376         list_del(&v9ses->slist);
377         spin_unlock(&v9fs_sessionlist_lock);
378 }
379
380 /**
381  * v9fs_session_cancel - terminate a session
382  * @v9ses: session to terminate
383  *
384  * mark transport as disconnected and cancel all pending requests.
385  */
386
387 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
388         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
389         p9_client_disconnect(v9ses->clnt);
390 }
391
392 /**
393  * v9fs_session_begin_cancel - Begin terminate of a session
394  * @v9ses: session to terminate
395  *
396  * After this call we don't allow any request other than clunk.
397  */
398
399 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
400 {
401         P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
402         p9_client_begin_disconnect(v9ses->clnt);
403 }
404
405 extern int v9fs_error_init(void);
406
407 static struct kobject *v9fs_kobj;
408
409 #ifdef CONFIG_9P_FSCACHE
410 /**
411  * caches_show - list caches associated with a session
412  *
413  * Returns the size of buffer written.
414  */
415
416 static ssize_t caches_show(struct kobject *kobj,
417                            struct kobj_attribute *attr,
418                            char *buf)
419 {
420         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
421         struct v9fs_session_info *v9ses;
422
423         spin_lock(&v9fs_sessionlist_lock);
424         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
425                 if (v9ses->cachetag) {
426                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
427                         if (n < 0) {
428                                 count = n;
429                                 break;
430                         }
431
432                         count += n;
433                         limit -= n;
434                 }
435         }
436
437         spin_unlock(&v9fs_sessionlist_lock);
438         return count;
439 }
440
441 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
442 #endif /* CONFIG_9P_FSCACHE */
443
444 static struct attribute *v9fs_attrs[] = {
445 #ifdef CONFIG_9P_FSCACHE
446         &v9fs_attr_cache.attr,
447 #endif
448         NULL,
449 };
450
451 static struct attribute_group v9fs_attr_group = {
452         .attrs = v9fs_attrs,
453 };
454
455 /**
456  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
457  *
458  */
459
460 static int v9fs_sysfs_init(void)
461 {
462         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
463         if (!v9fs_kobj)
464                 return -ENOMEM;
465
466         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
467                 kobject_put(v9fs_kobj);
468                 return -ENOMEM;
469         }
470
471         return 0;
472 }
473
474 /**
475  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
476  *
477  */
478
479 static void v9fs_sysfs_cleanup(void)
480 {
481         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
482         kobject_put(v9fs_kobj);
483 }
484
485 static void v9fs_inode_init_once(void *foo)
486 {
487         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
488 #ifdef CONFIG_9P_FSCACHE
489         v9inode->fscache = NULL;
490 #endif
491         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
492         inode_init_once(&v9inode->vfs_inode);
493 }
494
495 /**
496  * v9fs_init_inode_cache - initialize a cache for 9P
497  * Returns 0 on success.
498  */
499 static int v9fs_init_inode_cache(void)
500 {
501         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
502                                           sizeof(struct v9fs_inode),
503                                           0, (SLAB_RECLAIM_ACCOUNT|
504                                               SLAB_MEM_SPREAD),
505                                           v9fs_inode_init_once);
506         if (!v9fs_inode_cache)
507                 return -ENOMEM;
508
509         return 0;
510 }
511
512 /**
513  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
514  *
515  */
516 static void v9fs_destroy_inode_cache(void)
517 {
518         kmem_cache_destroy(v9fs_inode_cache);
519 }
520
521 static int v9fs_cache_register(void)
522 {
523         int ret;
524         ret = v9fs_init_inode_cache();
525         if (ret < 0)
526                 return ret;
527 #ifdef CONFIG_9P_FSCACHE
528         return fscache_register_netfs(&v9fs_cache_netfs);
529 #else
530         return ret;
531 #endif
532 }
533
534 static void v9fs_cache_unregister(void)
535 {
536         v9fs_destroy_inode_cache();
537 #ifdef CONFIG_9P_FSCACHE
538         fscache_unregister_netfs(&v9fs_cache_netfs);
539 #endif
540 }
541
542 /**
543  * init_v9fs - Initialize module
544  *
545  */
546
547 static int __init init_v9fs(void)
548 {
549         int err;
550         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
551         /* TODO: Setup list of registered trasnport modules */
552         err = register_filesystem(&v9fs_fs_type);
553         if (err < 0) {
554                 printk(KERN_ERR "Failed to register filesystem\n");
555                 return err;
556         }
557
558         err = v9fs_cache_register();
559         if (err < 0) {
560                 printk(KERN_ERR "Failed to register v9fs for caching\n");
561                 goto out_fs_unreg;
562         }
563
564         err = v9fs_sysfs_init();
565         if (err < 0) {
566                 printk(KERN_ERR "Failed to register with sysfs\n");
567                 goto out_sysfs_cleanup;
568         }
569
570         return 0;
571
572 out_sysfs_cleanup:
573         v9fs_sysfs_cleanup();
574
575 out_fs_unreg:
576         unregister_filesystem(&v9fs_fs_type);
577
578         return err;
579 }
580
581 /**
582  * exit_v9fs - shutdown module
583  *
584  */
585
586 static void __exit exit_v9fs(void)
587 {
588         v9fs_sysfs_cleanup();
589         v9fs_cache_unregister();
590         unregister_filesystem(&v9fs_fs_type);
591 }
592
593 module_init(init_v9fs)
594 module_exit(exit_v9fs)
595
596 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
597 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
598 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
599 MODULE_LICENSE("GPL");