fs/9p: Cleanup option parsing in 9p
[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, r;
136                 if (!*p)
137                         continue;
138                 token = match_token(p, tokens, args);
139                 switch (token) {
140                 case Opt_debug:
141                         r = match_int(&args[0], &option);
142                         if (r < 0) {
143                                 P9_DPRINTK(P9_DEBUG_ERROR,
144                                            "integer field, but no integer?\n");
145                                 ret = r;
146                                 continue;
147                         }
148                         v9ses->debug = option;
149 #ifdef CONFIG_NET_9P_DEBUG
150                         p9_debug_level = option;
151 #endif
152                         break;
153
154                 case Opt_dfltuid:
155                         r = match_int(&args[0], &option);
156                         if (r < 0) {
157                                 P9_DPRINTK(P9_DEBUG_ERROR,
158                                            "integer field, but no integer?\n");
159                                 ret = r;
160                                 continue;
161                         }
162                         v9ses->dfltuid = option;
163                         break;
164                 case Opt_dfltgid:
165                         r = match_int(&args[0], &option);
166                         if (r < 0) {
167                                 P9_DPRINTK(P9_DEBUG_ERROR,
168                                            "integer field, but no integer?\n");
169                                 ret = r;
170                                 continue;
171                         }
172                         v9ses->dfltgid = option;
173                         break;
174                 case Opt_afid:
175                         r = match_int(&args[0], &option);
176                         if (r < 0) {
177                                 P9_DPRINTK(P9_DEBUG_ERROR,
178                                            "integer field, but no integer?\n");
179                                 ret = r;
180                                 continue;
181                         }
182                         v9ses->afid = option;
183                         break;
184                 case Opt_uname:
185                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
186                         break;
187                 case Opt_remotename:
188                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
189                         break;
190                 case Opt_nodevmap:
191                         v9ses->nodev = 1;
192                         break;
193                 case Opt_cache_loose:
194                         v9ses->cache = CACHE_LOOSE;
195                         break;
196                 case Opt_fscache:
197                         v9ses->cache = CACHE_FSCACHE;
198                         break;
199                 case Opt_cachetag:
200 #ifdef CONFIG_9P_FSCACHE
201                         v9ses->cachetag = match_strdup(&args[0]);
202 #endif
203                         break;
204                 case Opt_cache:
205                         s = match_strdup(&args[0]);
206                         if (!s) {
207                                 ret = -ENOMEM;
208                                 P9_DPRINTK(P9_DEBUG_ERROR,
209                                   "problem allocating copy of cache arg\n");
210                                 goto free_and_return;
211                         }
212                         ret = get_cache_mode(s);
213                         if (ret == -EINVAL) {
214                                 kfree(s);
215                                 goto free_and_return;
216                         }
217
218                         v9ses->cache = ret;
219                         kfree(s);
220                         break;
221
222                 case Opt_access:
223                         s = match_strdup(&args[0]);
224                         if (!s) {
225                                 ret = -ENOMEM;
226                                 P9_DPRINTK(P9_DEBUG_ERROR,
227                                   "problem allocating copy of access arg\n");
228                                 goto free_and_return;
229                         }
230
231                         v9ses->flags &= ~V9FS_ACCESS_MASK;
232                         if (strcmp(s, "user") == 0)
233                                 v9ses->flags |= V9FS_ACCESS_USER;
234                         else if (strcmp(s, "any") == 0)
235                                 v9ses->flags |= V9FS_ACCESS_ANY;
236                         else if (strcmp(s, "client") == 0) {
237                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
238                         } else {
239                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
240                                 v9ses->uid = simple_strtoul(s, &e, 10);
241                                 if (*e != '\0') {
242                                         ret = -EINVAL;
243                                         printk(KERN_INFO "9p: Unknown access "
244                                                         "argument %s.\n", s);
245                                         kfree(s);
246                                         goto free_and_return;
247                                 }
248                         }
249
250                         kfree(s);
251                         break;
252
253                 case Opt_posixacl:
254 #ifdef CONFIG_9P_FS_POSIX_ACL
255                         v9ses->flags |= V9FS_POSIX_ACL;
256 #else
257                         P9_DPRINTK(P9_DEBUG_ERROR,
258                                         "Not defined CONFIG_9P_FS_POSIX_ACL. "
259                                         "Ignoring posixacl option\n");
260 #endif
261                         break;
262
263                 default:
264                         continue;
265                 }
266         }
267
268 free_and_return:
269         kfree(tmp_options);
270 fail_option_alloc:
271         return ret;
272 }
273
274 /**
275  * v9fs_session_init - initialize session
276  * @v9ses: session information structure
277  * @dev_name: device being mounted
278  * @data: options
279  *
280  */
281
282 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
283                   const char *dev_name, char *data)
284 {
285         int retval = -EINVAL;
286         struct p9_fid *fid;
287         int rc;
288
289         v9ses->uname = __getname();
290         if (!v9ses->uname)
291                 return ERR_PTR(-ENOMEM);
292
293         v9ses->aname = __getname();
294         if (!v9ses->aname) {
295                 __putname(v9ses->uname);
296                 return ERR_PTR(-ENOMEM);
297         }
298         init_rwsem(&v9ses->rename_sem);
299
300         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
301         if (rc) {
302                 __putname(v9ses->aname);
303                 __putname(v9ses->uname);
304                 return ERR_PTR(rc);
305         }
306
307         spin_lock(&v9fs_sessionlist_lock);
308         list_add(&v9ses->slist, &v9fs_sessionlist);
309         spin_unlock(&v9fs_sessionlist_lock);
310
311         strcpy(v9ses->uname, V9FS_DEFUSER);
312         strcpy(v9ses->aname, V9FS_DEFANAME);
313         v9ses->uid = ~0;
314         v9ses->dfltuid = V9FS_DEFUID;
315         v9ses->dfltgid = V9FS_DEFGID;
316
317         v9ses->clnt = p9_client_create(dev_name, data);
318         if (IS_ERR(v9ses->clnt)) {
319                 retval = PTR_ERR(v9ses->clnt);
320                 v9ses->clnt = NULL;
321                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
322                 goto error;
323         }
324
325         v9ses->flags = V9FS_ACCESS_USER;
326
327         if (p9_is_proto_dotl(v9ses->clnt)) {
328                 v9ses->flags = V9FS_ACCESS_CLIENT;
329                 v9ses->flags |= V9FS_PROTO_2000L;
330         } else if (p9_is_proto_dotu(v9ses->clnt)) {
331                 v9ses->flags |= V9FS_PROTO_2000U;
332         }
333
334         rc = v9fs_parse_options(v9ses, data);
335         if (rc < 0) {
336                 retval = rc;
337                 goto error;
338         }
339
340         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
341
342         if (!v9fs_proto_dotl(v9ses) &&
343             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
344                 /*
345                  * We support ACCESS_CLIENT only for dotl.
346                  * Fall back to ACCESS_USER
347                  */
348                 v9ses->flags &= ~V9FS_ACCESS_MASK;
349                 v9ses->flags |= V9FS_ACCESS_USER;
350         }
351         /*FIXME !! */
352         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
353         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
354                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
355
356                 v9ses->flags &= ~V9FS_ACCESS_MASK;
357                 v9ses->flags |= V9FS_ACCESS_ANY;
358                 v9ses->uid = ~0;
359         }
360         if (!v9fs_proto_dotl(v9ses) ||
361                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
362                 /*
363                  * We support ACL checks on clinet only if the protocol is
364                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
365                  */
366                 v9ses->flags &= ~V9FS_ACL_MASK;
367         }
368
369         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
370                                                         v9ses->aname);
371         if (IS_ERR(fid)) {
372                 retval = PTR_ERR(fid);
373                 fid = NULL;
374                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
375                 goto error;
376         }
377
378         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
379                 fid->uid = v9ses->uid;
380         else
381                 fid->uid = ~0;
382
383 #ifdef CONFIG_9P_FSCACHE
384         /* register the session for caching */
385         v9fs_cache_session_get_cookie(v9ses);
386 #endif
387
388         return fid;
389
390 error:
391         bdi_destroy(&v9ses->bdi);
392         return ERR_PTR(retval);
393 }
394
395 /**
396  * v9fs_session_close - shutdown a session
397  * @v9ses: session information structure
398  *
399  */
400
401 void v9fs_session_close(struct v9fs_session_info *v9ses)
402 {
403         if (v9ses->clnt) {
404                 p9_client_destroy(v9ses->clnt);
405                 v9ses->clnt = NULL;
406         }
407
408 #ifdef CONFIG_9P_FSCACHE
409         if (v9ses->fscache) {
410                 v9fs_cache_session_put_cookie(v9ses);
411                 kfree(v9ses->cachetag);
412         }
413 #endif
414         __putname(v9ses->uname);
415         __putname(v9ses->aname);
416
417         bdi_destroy(&v9ses->bdi);
418
419         spin_lock(&v9fs_sessionlist_lock);
420         list_del(&v9ses->slist);
421         spin_unlock(&v9fs_sessionlist_lock);
422 }
423
424 /**
425  * v9fs_session_cancel - terminate a session
426  * @v9ses: session to terminate
427  *
428  * mark transport as disconnected and cancel all pending requests.
429  */
430
431 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
432         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
433         p9_client_disconnect(v9ses->clnt);
434 }
435
436 /**
437  * v9fs_session_begin_cancel - Begin terminate of a session
438  * @v9ses: session to terminate
439  *
440  * After this call we don't allow any request other than clunk.
441  */
442
443 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
444 {
445         P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
446         p9_client_begin_disconnect(v9ses->clnt);
447 }
448
449 extern int v9fs_error_init(void);
450
451 static struct kobject *v9fs_kobj;
452
453 #ifdef CONFIG_9P_FSCACHE
454 /**
455  * caches_show - list caches associated with a session
456  *
457  * Returns the size of buffer written.
458  */
459
460 static ssize_t caches_show(struct kobject *kobj,
461                            struct kobj_attribute *attr,
462                            char *buf)
463 {
464         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
465         struct v9fs_session_info *v9ses;
466
467         spin_lock(&v9fs_sessionlist_lock);
468         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
469                 if (v9ses->cachetag) {
470                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
471                         if (n < 0) {
472                                 count = n;
473                                 break;
474                         }
475
476                         count += n;
477                         limit -= n;
478                 }
479         }
480
481         spin_unlock(&v9fs_sessionlist_lock);
482         return count;
483 }
484
485 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
486 #endif /* CONFIG_9P_FSCACHE */
487
488 static struct attribute *v9fs_attrs[] = {
489 #ifdef CONFIG_9P_FSCACHE
490         &v9fs_attr_cache.attr,
491 #endif
492         NULL,
493 };
494
495 static struct attribute_group v9fs_attr_group = {
496         .attrs = v9fs_attrs,
497 };
498
499 /**
500  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
501  *
502  */
503
504 static int v9fs_sysfs_init(void)
505 {
506         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
507         if (!v9fs_kobj)
508                 return -ENOMEM;
509
510         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
511                 kobject_put(v9fs_kobj);
512                 return -ENOMEM;
513         }
514
515         return 0;
516 }
517
518 /**
519  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
520  *
521  */
522
523 static void v9fs_sysfs_cleanup(void)
524 {
525         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
526         kobject_put(v9fs_kobj);
527 }
528
529 static void v9fs_inode_init_once(void *foo)
530 {
531         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
532 #ifdef CONFIG_9P_FSCACHE
533         v9inode->fscache = NULL;
534 #endif
535         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
536         inode_init_once(&v9inode->vfs_inode);
537 }
538
539 /**
540  * v9fs_init_inode_cache - initialize a cache for 9P
541  * Returns 0 on success.
542  */
543 static int v9fs_init_inode_cache(void)
544 {
545         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
546                                           sizeof(struct v9fs_inode),
547                                           0, (SLAB_RECLAIM_ACCOUNT|
548                                               SLAB_MEM_SPREAD),
549                                           v9fs_inode_init_once);
550         if (!v9fs_inode_cache)
551                 return -ENOMEM;
552
553         return 0;
554 }
555
556 /**
557  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
558  *
559  */
560 static void v9fs_destroy_inode_cache(void)
561 {
562         kmem_cache_destroy(v9fs_inode_cache);
563 }
564
565 static int v9fs_cache_register(void)
566 {
567         int ret;
568         ret = v9fs_init_inode_cache();
569         if (ret < 0)
570                 return ret;
571 #ifdef CONFIG_9P_FSCACHE
572         return fscache_register_netfs(&v9fs_cache_netfs);
573 #else
574         return ret;
575 #endif
576 }
577
578 static void v9fs_cache_unregister(void)
579 {
580         v9fs_destroy_inode_cache();
581 #ifdef CONFIG_9P_FSCACHE
582         fscache_unregister_netfs(&v9fs_cache_netfs);
583 #endif
584 }
585
586 /**
587  * init_v9fs - Initialize module
588  *
589  */
590
591 static int __init init_v9fs(void)
592 {
593         int err;
594         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
595         /* TODO: Setup list of registered trasnport modules */
596         err = register_filesystem(&v9fs_fs_type);
597         if (err < 0) {
598                 printk(KERN_ERR "Failed to register filesystem\n");
599                 return err;
600         }
601
602         err = v9fs_cache_register();
603         if (err < 0) {
604                 printk(KERN_ERR "Failed to register v9fs for caching\n");
605                 goto out_fs_unreg;
606         }
607
608         err = v9fs_sysfs_init();
609         if (err < 0) {
610                 printk(KERN_ERR "Failed to register with sysfs\n");
611                 goto out_sysfs_cleanup;
612         }
613
614         return 0;
615
616 out_sysfs_cleanup:
617         v9fs_sysfs_cleanup();
618
619 out_fs_unreg:
620         unregister_filesystem(&v9fs_fs_type);
621
622         return err;
623 }
624
625 /**
626  * exit_v9fs - shutdown module
627  *
628  */
629
630 static void __exit exit_v9fs(void)
631 {
632         v9fs_sysfs_cleanup();
633         v9fs_cache_unregister();
634         unregister_filesystem(&v9fs_fs_type);
635 }
636
637 module_init(init_v9fs)
638 module_exit(exit_v9fs)
639
640 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
641 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
642 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
643 MODULE_LICENSE("GPL");