9p: Reduce object size with CONFIG_NET_9P_DEBUG
[linux-3.10.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,
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_cachetag, "cachetag=%s"},
78         {Opt_access, "access=%s"},
79         {Opt_posixacl, "posixacl"},
80         {Opt_err, NULL}
81 };
82
83 /* Interpret mount options for cache mode */
84 static int get_cache_mode(char *s)
85 {
86         int version = -EINVAL;
87
88         if (!strcmp(s, "loose")) {
89                 version = CACHE_LOOSE;
90                 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
91         } else if (!strcmp(s, "fscache")) {
92                 version = CACHE_FSCACHE;
93                 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
94         } else if (!strcmp(s, "none")) {
95                 version = CACHE_NONE;
96                 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
97         } else
98                 pr_info("Unknown Cache mode %s\n", s);
99         return version;
100 }
101
102 /**
103  * v9fs_parse_options - parse mount options into session structure
104  * @v9ses: existing v9fs session information
105  *
106  * Return 0 upon success, -ERRNO upon failure.
107  */
108
109 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
110 {
111         char *options, *tmp_options;
112         substring_t args[MAX_OPT_ARGS];
113         char *p;
114         int option = 0;
115         char *s, *e;
116         int ret = 0;
117
118         /* setup defaults */
119         v9ses->afid = ~0;
120         v9ses->debug = 0;
121         v9ses->cache = CACHE_NONE;
122 #ifdef CONFIG_9P_FSCACHE
123         v9ses->cachetag = NULL;
124 #endif
125
126         if (!opts)
127                 return 0;
128
129         tmp_options = kstrdup(opts, GFP_KERNEL);
130         if (!tmp_options) {
131                 ret = -ENOMEM;
132                 goto fail_option_alloc;
133         }
134         options = tmp_options;
135
136         while ((p = strsep(&options, ",")) != NULL) {
137                 int token, r;
138                 if (!*p)
139                         continue;
140                 token = match_token(p, tokens, args);
141                 switch (token) {
142                 case Opt_debug:
143                         r = match_int(&args[0], &option);
144                         if (r < 0) {
145                                 p9_debug(P9_DEBUG_ERROR,
146                                          "integer field, but no integer?\n");
147                                 ret = r;
148                                 continue;
149                         }
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                         r = match_int(&args[0], &option);
158                         if (r < 0) {
159                                 p9_debug(P9_DEBUG_ERROR,
160                                          "integer field, but no integer?\n");
161                                 ret = r;
162                                 continue;
163                         }
164                         v9ses->dfltuid = option;
165                         break;
166                 case Opt_dfltgid:
167                         r = match_int(&args[0], &option);
168                         if (r < 0) {
169                                 p9_debug(P9_DEBUG_ERROR,
170                                          "integer field, but no integer?\n");
171                                 ret = r;
172                                 continue;
173                         }
174                         v9ses->dfltgid = option;
175                         break;
176                 case Opt_afid:
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->afid = option;
185                         break;
186                 case Opt_uname:
187                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
188                         break;
189                 case Opt_remotename:
190                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
191                         break;
192                 case Opt_nodevmap:
193                         v9ses->nodev = 1;
194                         break;
195                 case Opt_cache_loose:
196                         v9ses->cache = CACHE_LOOSE;
197                         break;
198                 case Opt_fscache:
199                         v9ses->cache = CACHE_FSCACHE;
200                         break;
201                 case Opt_cachetag:
202 #ifdef CONFIG_9P_FSCACHE
203                         v9ses->cachetag = match_strdup(&args[0]);
204 #endif
205                         break;
206                 case Opt_cache:
207                         s = match_strdup(&args[0]);
208                         if (!s) {
209                                 ret = -ENOMEM;
210                                 p9_debug(P9_DEBUG_ERROR,
211                                          "problem allocating copy of cache arg\n");
212                                 goto free_and_return;
213                         }
214                         ret = get_cache_mode(s);
215                         if (ret == -EINVAL) {
216                                 kfree(s);
217                                 goto free_and_return;
218                         }
219
220                         v9ses->cache = ret;
221                         kfree(s);
222                         break;
223
224                 case Opt_access:
225                         s = match_strdup(&args[0]);
226                         if (!s) {
227                                 ret = -ENOMEM;
228                                 p9_debug(P9_DEBUG_ERROR,
229                                          "problem allocating copy of access arg\n");
230                                 goto free_and_return;
231                         }
232
233                         v9ses->flags &= ~V9FS_ACCESS_MASK;
234                         if (strcmp(s, "user") == 0)
235                                 v9ses->flags |= V9FS_ACCESS_USER;
236                         else if (strcmp(s, "any") == 0)
237                                 v9ses->flags |= V9FS_ACCESS_ANY;
238                         else if (strcmp(s, "client") == 0) {
239                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
240                         } else {
241                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
242                                 v9ses->uid = simple_strtoul(s, &e, 10);
243                                 if (*e != '\0') {
244                                         ret = -EINVAL;
245                                         pr_info("Unknown access argument %s\n",
246                                                 s);
247                                         kfree(s);
248                                         goto free_and_return;
249                                 }
250                         }
251
252                         kfree(s);
253                         break;
254
255                 case Opt_posixacl:
256 #ifdef CONFIG_9P_FS_POSIX_ACL
257                         v9ses->flags |= V9FS_POSIX_ACL;
258 #else
259                         p9_debug(P9_DEBUG_ERROR,
260                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
261 #endif
262                         break;
263
264                 default:
265                         continue;
266                 }
267         }
268
269 free_and_return:
270         kfree(tmp_options);
271 fail_option_alloc:
272         return ret;
273 }
274
275 /**
276  * v9fs_session_init - initialize session
277  * @v9ses: session information structure
278  * @dev_name: device being mounted
279  * @data: options
280  *
281  */
282
283 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
284                   const char *dev_name, char *data)
285 {
286         int retval = -EINVAL;
287         struct p9_fid *fid;
288         int rc;
289
290         v9ses->uname = __getname();
291         if (!v9ses->uname)
292                 return ERR_PTR(-ENOMEM);
293
294         v9ses->aname = __getname();
295         if (!v9ses->aname) {
296                 __putname(v9ses->uname);
297                 return ERR_PTR(-ENOMEM);
298         }
299         init_rwsem(&v9ses->rename_sem);
300
301         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
302         if (rc) {
303                 __putname(v9ses->aname);
304                 __putname(v9ses->uname);
305                 return ERR_PTR(rc);
306         }
307
308         spin_lock(&v9fs_sessionlist_lock);
309         list_add(&v9ses->slist, &v9fs_sessionlist);
310         spin_unlock(&v9fs_sessionlist_lock);
311
312         strcpy(v9ses->uname, V9FS_DEFUSER);
313         strcpy(v9ses->aname, V9FS_DEFANAME);
314         v9ses->uid = ~0;
315         v9ses->dfltuid = V9FS_DEFUID;
316         v9ses->dfltgid = V9FS_DEFGID;
317
318         v9ses->clnt = p9_client_create(dev_name, data);
319         if (IS_ERR(v9ses->clnt)) {
320                 retval = PTR_ERR(v9ses->clnt);
321                 v9ses->clnt = NULL;
322                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
323                 goto error;
324         }
325
326         v9ses->flags = V9FS_ACCESS_USER;
327
328         if (p9_is_proto_dotl(v9ses->clnt)) {
329                 v9ses->flags = V9FS_ACCESS_CLIENT;
330                 v9ses->flags |= V9FS_PROTO_2000L;
331         } else if (p9_is_proto_dotu(v9ses->clnt)) {
332                 v9ses->flags |= V9FS_PROTO_2000U;
333         }
334
335         rc = v9fs_parse_options(v9ses, data);
336         if (rc < 0) {
337                 retval = rc;
338                 goto error;
339         }
340
341         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
342
343         if (!v9fs_proto_dotl(v9ses) &&
344             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
345                 /*
346                  * We support ACCESS_CLIENT only for dotl.
347                  * Fall back to ACCESS_USER
348                  */
349                 v9ses->flags &= ~V9FS_ACCESS_MASK;
350                 v9ses->flags |= V9FS_ACCESS_USER;
351         }
352         /*FIXME !! */
353         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
354         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
355                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
356
357                 v9ses->flags &= ~V9FS_ACCESS_MASK;
358                 v9ses->flags |= V9FS_ACCESS_ANY;
359                 v9ses->uid = ~0;
360         }
361         if (!v9fs_proto_dotl(v9ses) ||
362                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
363                 /*
364                  * We support ACL checks on clinet only if the protocol is
365                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
366                  */
367                 v9ses->flags &= ~V9FS_ACL_MASK;
368         }
369
370         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
371                                                         v9ses->aname);
372         if (IS_ERR(fid)) {
373                 retval = PTR_ERR(fid);
374                 fid = NULL;
375                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
376                 goto error;
377         }
378
379         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
380                 fid->uid = v9ses->uid;
381         else
382                 fid->uid = ~0;
383
384 #ifdef CONFIG_9P_FSCACHE
385         /* register the session for caching */
386         v9fs_cache_session_get_cookie(v9ses);
387 #endif
388
389         return fid;
390
391 error:
392         bdi_destroy(&v9ses->bdi);
393         return ERR_PTR(retval);
394 }
395
396 /**
397  * v9fs_session_close - shutdown a session
398  * @v9ses: session information structure
399  *
400  */
401
402 void v9fs_session_close(struct v9fs_session_info *v9ses)
403 {
404         if (v9ses->clnt) {
405                 p9_client_destroy(v9ses->clnt);
406                 v9ses->clnt = NULL;
407         }
408
409 #ifdef CONFIG_9P_FSCACHE
410         if (v9ses->fscache) {
411                 v9fs_cache_session_put_cookie(v9ses);
412                 kfree(v9ses->cachetag);
413         }
414 #endif
415         __putname(v9ses->uname);
416         __putname(v9ses->aname);
417
418         bdi_destroy(&v9ses->bdi);
419
420         spin_lock(&v9fs_sessionlist_lock);
421         list_del(&v9ses->slist);
422         spin_unlock(&v9fs_sessionlist_lock);
423 }
424
425 /**
426  * v9fs_session_cancel - terminate a session
427  * @v9ses: session to terminate
428  *
429  * mark transport as disconnected and cancel all pending requests.
430  */
431
432 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
433         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
434         p9_client_disconnect(v9ses->clnt);
435 }
436
437 /**
438  * v9fs_session_begin_cancel - Begin terminate of a session
439  * @v9ses: session to terminate
440  *
441  * After this call we don't allow any request other than clunk.
442  */
443
444 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
445 {
446         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
447         p9_client_begin_disconnect(v9ses->clnt);
448 }
449
450 extern int v9fs_error_init(void);
451
452 static struct kobject *v9fs_kobj;
453
454 #ifdef CONFIG_9P_FSCACHE
455 /**
456  * caches_show - list caches associated with a session
457  *
458  * Returns the size of buffer written.
459  */
460
461 static ssize_t caches_show(struct kobject *kobj,
462                            struct kobj_attribute *attr,
463                            char *buf)
464 {
465         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
466         struct v9fs_session_info *v9ses;
467
468         spin_lock(&v9fs_sessionlist_lock);
469         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
470                 if (v9ses->cachetag) {
471                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
472                         if (n < 0) {
473                                 count = n;
474                                 break;
475                         }
476
477                         count += n;
478                         limit -= n;
479                 }
480         }
481
482         spin_unlock(&v9fs_sessionlist_lock);
483         return count;
484 }
485
486 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
487 #endif /* CONFIG_9P_FSCACHE */
488
489 static struct attribute *v9fs_attrs[] = {
490 #ifdef CONFIG_9P_FSCACHE
491         &v9fs_attr_cache.attr,
492 #endif
493         NULL,
494 };
495
496 static struct attribute_group v9fs_attr_group = {
497         .attrs = v9fs_attrs,
498 };
499
500 /**
501  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
502  *
503  */
504
505 static int v9fs_sysfs_init(void)
506 {
507         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
508         if (!v9fs_kobj)
509                 return -ENOMEM;
510
511         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
512                 kobject_put(v9fs_kobj);
513                 return -ENOMEM;
514         }
515
516         return 0;
517 }
518
519 /**
520  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
521  *
522  */
523
524 static void v9fs_sysfs_cleanup(void)
525 {
526         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
527         kobject_put(v9fs_kobj);
528 }
529
530 static void v9fs_inode_init_once(void *foo)
531 {
532         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
533 #ifdef CONFIG_9P_FSCACHE
534         v9inode->fscache = NULL;
535 #endif
536         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
537         inode_init_once(&v9inode->vfs_inode);
538 }
539
540 /**
541  * v9fs_init_inode_cache - initialize a cache for 9P
542  * Returns 0 on success.
543  */
544 static int v9fs_init_inode_cache(void)
545 {
546         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
547                                           sizeof(struct v9fs_inode),
548                                           0, (SLAB_RECLAIM_ACCOUNT|
549                                               SLAB_MEM_SPREAD),
550                                           v9fs_inode_init_once);
551         if (!v9fs_inode_cache)
552                 return -ENOMEM;
553
554         return 0;
555 }
556
557 /**
558  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
559  *
560  */
561 static void v9fs_destroy_inode_cache(void)
562 {
563         kmem_cache_destroy(v9fs_inode_cache);
564 }
565
566 static int v9fs_cache_register(void)
567 {
568         int ret;
569         ret = v9fs_init_inode_cache();
570         if (ret < 0)
571                 return ret;
572 #ifdef CONFIG_9P_FSCACHE
573         return fscache_register_netfs(&v9fs_cache_netfs);
574 #else
575         return ret;
576 #endif
577 }
578
579 static void v9fs_cache_unregister(void)
580 {
581         v9fs_destroy_inode_cache();
582 #ifdef CONFIG_9P_FSCACHE
583         fscache_unregister_netfs(&v9fs_cache_netfs);
584 #endif
585 }
586
587 /**
588  * init_v9fs - Initialize module
589  *
590  */
591
592 static int __init init_v9fs(void)
593 {
594         int err;
595         pr_info("Installing v9fs 9p2000 file system support\n");
596         /* TODO: Setup list of registered trasnport modules */
597         err = register_filesystem(&v9fs_fs_type);
598         if (err < 0) {
599                 pr_err("Failed to register filesystem\n");
600                 return err;
601         }
602
603         err = v9fs_cache_register();
604         if (err < 0) {
605                 pr_err("Failed to register v9fs for caching\n");
606                 goto out_fs_unreg;
607         }
608
609         err = v9fs_sysfs_init();
610         if (err < 0) {
611                 pr_err("Failed to register with sysfs\n");
612                 goto out_sysfs_cleanup;
613         }
614
615         return 0;
616
617 out_sysfs_cleanup:
618         v9fs_sysfs_cleanup();
619
620 out_fs_unreg:
621         unregister_filesystem(&v9fs_fs_type);
622
623         return err;
624 }
625
626 /**
627  * exit_v9fs - shutdown module
628  *
629  */
630
631 static void __exit exit_v9fs(void)
632 {
633         v9fs_sysfs_cleanup();
634         v9fs_cache_unregister();
635         unregister_filesystem(&v9fs_fs_type);
636 }
637
638 module_init(init_v9fs)
639 module_exit(exit_v9fs)
640
641 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
642 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
643 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
644 MODULE_LICENSE("GPL");