btrfs: try harder to allocate raid56 stripe cache
[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                         kfree(v9ses->uname);
188                         v9ses->uname = match_strdup(&args[0]);
189                         if (!v9ses->uname) {
190                                 ret = -ENOMEM;
191                                 goto free_and_return;
192                         }
193                         break;
194                 case Opt_remotename:
195                         kfree(v9ses->aname);
196                         v9ses->aname = match_strdup(&args[0]);
197                         if (!v9ses->aname) {
198                                 ret = -ENOMEM;
199                                 goto free_and_return;
200                         }
201                         break;
202                 case Opt_nodevmap:
203                         v9ses->nodev = 1;
204                         break;
205                 case Opt_cache_loose:
206                         v9ses->cache = CACHE_LOOSE;
207                         break;
208                 case Opt_fscache:
209                         v9ses->cache = CACHE_FSCACHE;
210                         break;
211                 case Opt_cachetag:
212 #ifdef CONFIG_9P_FSCACHE
213                         v9ses->cachetag = match_strdup(&args[0]);
214 #endif
215                         break;
216                 case Opt_cache:
217                         s = match_strdup(&args[0]);
218                         if (!s) {
219                                 ret = -ENOMEM;
220                                 p9_debug(P9_DEBUG_ERROR,
221                                          "problem allocating copy of cache arg\n");
222                                 goto free_and_return;
223                         }
224                         ret = get_cache_mode(s);
225                         if (ret == -EINVAL) {
226                                 kfree(s);
227                                 goto free_and_return;
228                         }
229
230                         v9ses->cache = ret;
231                         kfree(s);
232                         break;
233
234                 case Opt_access:
235                         s = match_strdup(&args[0]);
236                         if (!s) {
237                                 ret = -ENOMEM;
238                                 p9_debug(P9_DEBUG_ERROR,
239                                          "problem allocating copy of access arg\n");
240                                 goto free_and_return;
241                         }
242
243                         v9ses->flags &= ~V9FS_ACCESS_MASK;
244                         if (strcmp(s, "user") == 0)
245                                 v9ses->flags |= V9FS_ACCESS_USER;
246                         else if (strcmp(s, "any") == 0)
247                                 v9ses->flags |= V9FS_ACCESS_ANY;
248                         else if (strcmp(s, "client") == 0) {
249                                 v9ses->flags |= V9FS_ACCESS_CLIENT;
250                         } else {
251                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
252                                 v9ses->uid = simple_strtoul(s, &e, 10);
253                                 if (*e != '\0') {
254                                         ret = -EINVAL;
255                                         pr_info("Unknown access argument %s\n",
256                                                 s);
257                                         kfree(s);
258                                         goto free_and_return;
259                                 }
260                         }
261
262                         kfree(s);
263                         break;
264
265                 case Opt_posixacl:
266 #ifdef CONFIG_9P_FS_POSIX_ACL
267                         v9ses->flags |= V9FS_POSIX_ACL;
268 #else
269                         p9_debug(P9_DEBUG_ERROR,
270                                  "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
271 #endif
272                         break;
273
274                 default:
275                         continue;
276                 }
277         }
278
279 free_and_return:
280         kfree(tmp_options);
281 fail_option_alloc:
282         return ret;
283 }
284
285 /**
286  * v9fs_session_init - initialize session
287  * @v9ses: session information structure
288  * @dev_name: device being mounted
289  * @data: options
290  *
291  */
292
293 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
294                   const char *dev_name, char *data)
295 {
296         int retval = -EINVAL;
297         struct p9_fid *fid;
298         int rc;
299
300         v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
301         if (!v9ses->uname)
302                 return ERR_PTR(-ENOMEM);
303
304         v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
305         if (!v9ses->aname) {
306                 kfree(v9ses->uname);
307                 return ERR_PTR(-ENOMEM);
308         }
309         init_rwsem(&v9ses->rename_sem);
310
311         rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
312         if (rc) {
313                 kfree(v9ses->aname);
314                 kfree(v9ses->uname);
315                 return ERR_PTR(rc);
316         }
317
318         spin_lock(&v9fs_sessionlist_lock);
319         list_add(&v9ses->slist, &v9fs_sessionlist);
320         spin_unlock(&v9fs_sessionlist_lock);
321
322         v9ses->uid = ~0;
323         v9ses->dfltuid = V9FS_DEFUID;
324         v9ses->dfltgid = V9FS_DEFGID;
325
326         v9ses->clnt = p9_client_create(dev_name, data);
327         if (IS_ERR(v9ses->clnt)) {
328                 retval = PTR_ERR(v9ses->clnt);
329                 v9ses->clnt = NULL;
330                 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
331                 goto error;
332         }
333
334         v9ses->flags = V9FS_ACCESS_USER;
335
336         if (p9_is_proto_dotl(v9ses->clnt)) {
337                 v9ses->flags = V9FS_ACCESS_CLIENT;
338                 v9ses->flags |= V9FS_PROTO_2000L;
339         } else if (p9_is_proto_dotu(v9ses->clnt)) {
340                 v9ses->flags |= V9FS_PROTO_2000U;
341         }
342
343         rc = v9fs_parse_options(v9ses, data);
344         if (rc < 0) {
345                 retval = rc;
346                 goto error;
347         }
348
349         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
350
351         if (!v9fs_proto_dotl(v9ses) &&
352             ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
353                 /*
354                  * We support ACCESS_CLIENT only for dotl.
355                  * Fall back to ACCESS_USER
356                  */
357                 v9ses->flags &= ~V9FS_ACCESS_MASK;
358                 v9ses->flags |= V9FS_ACCESS_USER;
359         }
360         /*FIXME !! */
361         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
362         if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
363                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
364
365                 v9ses->flags &= ~V9FS_ACCESS_MASK;
366                 v9ses->flags |= V9FS_ACCESS_ANY;
367                 v9ses->uid = ~0;
368         }
369         if (!v9fs_proto_dotl(v9ses) ||
370                 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
371                 /*
372                  * We support ACL checks on clinet only if the protocol is
373                  * 9P2000.L and access is V9FS_ACCESS_CLIENT.
374                  */
375                 v9ses->flags &= ~V9FS_ACL_MASK;
376         }
377
378         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
379                                                         v9ses->aname);
380         if (IS_ERR(fid)) {
381                 retval = PTR_ERR(fid);
382                 fid = NULL;
383                 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
384                 goto error;
385         }
386
387         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
388                 fid->uid = v9ses->uid;
389         else
390                 fid->uid = ~0;
391
392 #ifdef CONFIG_9P_FSCACHE
393         /* register the session for caching */
394         v9fs_cache_session_get_cookie(v9ses);
395 #endif
396
397         return fid;
398
399 error:
400         bdi_destroy(&v9ses->bdi);
401         return ERR_PTR(retval);
402 }
403
404 /**
405  * v9fs_session_close - shutdown a session
406  * @v9ses: session information structure
407  *
408  */
409
410 void v9fs_session_close(struct v9fs_session_info *v9ses)
411 {
412         if (v9ses->clnt) {
413                 p9_client_destroy(v9ses->clnt);
414                 v9ses->clnt = NULL;
415         }
416
417 #ifdef CONFIG_9P_FSCACHE
418         if (v9ses->fscache) {
419                 v9fs_cache_session_put_cookie(v9ses);
420                 kfree(v9ses->cachetag);
421         }
422 #endif
423         kfree(v9ses->uname);
424         kfree(v9ses->aname);
425
426         bdi_destroy(&v9ses->bdi);
427
428         spin_lock(&v9fs_sessionlist_lock);
429         list_del(&v9ses->slist);
430         spin_unlock(&v9fs_sessionlist_lock);
431 }
432
433 /**
434  * v9fs_session_cancel - terminate a session
435  * @v9ses: session to terminate
436  *
437  * mark transport as disconnected and cancel all pending requests.
438  */
439
440 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
441         p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
442         p9_client_disconnect(v9ses->clnt);
443 }
444
445 /**
446  * v9fs_session_begin_cancel - Begin terminate of a session
447  * @v9ses: session to terminate
448  *
449  * After this call we don't allow any request other than clunk.
450  */
451
452 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
453 {
454         p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
455         p9_client_begin_disconnect(v9ses->clnt);
456 }
457
458 extern int v9fs_error_init(void);
459
460 static struct kobject *v9fs_kobj;
461
462 #ifdef CONFIG_9P_FSCACHE
463 /**
464  * caches_show - list caches associated with a session
465  *
466  * Returns the size of buffer written.
467  */
468
469 static ssize_t caches_show(struct kobject *kobj,
470                            struct kobj_attribute *attr,
471                            char *buf)
472 {
473         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
474         struct v9fs_session_info *v9ses;
475
476         spin_lock(&v9fs_sessionlist_lock);
477         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
478                 if (v9ses->cachetag) {
479                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
480                         if (n < 0) {
481                                 count = n;
482                                 break;
483                         }
484
485                         count += n;
486                         limit -= n;
487                 }
488         }
489
490         spin_unlock(&v9fs_sessionlist_lock);
491         return count;
492 }
493
494 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
495 #endif /* CONFIG_9P_FSCACHE */
496
497 static struct attribute *v9fs_attrs[] = {
498 #ifdef CONFIG_9P_FSCACHE
499         &v9fs_attr_cache.attr,
500 #endif
501         NULL,
502 };
503
504 static struct attribute_group v9fs_attr_group = {
505         .attrs = v9fs_attrs,
506 };
507
508 /**
509  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
510  *
511  */
512
513 static int v9fs_sysfs_init(void)
514 {
515         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
516         if (!v9fs_kobj)
517                 return -ENOMEM;
518
519         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
520                 kobject_put(v9fs_kobj);
521                 return -ENOMEM;
522         }
523
524         return 0;
525 }
526
527 /**
528  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
529  *
530  */
531
532 static void v9fs_sysfs_cleanup(void)
533 {
534         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
535         kobject_put(v9fs_kobj);
536 }
537
538 static void v9fs_inode_init_once(void *foo)
539 {
540         struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
541 #ifdef CONFIG_9P_FSCACHE
542         v9inode->fscache = NULL;
543 #endif
544         memset(&v9inode->qid, 0, sizeof(v9inode->qid));
545         inode_init_once(&v9inode->vfs_inode);
546 }
547
548 /**
549  * v9fs_init_inode_cache - initialize a cache for 9P
550  * Returns 0 on success.
551  */
552 static int v9fs_init_inode_cache(void)
553 {
554         v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
555                                           sizeof(struct v9fs_inode),
556                                           0, (SLAB_RECLAIM_ACCOUNT|
557                                               SLAB_MEM_SPREAD),
558                                           v9fs_inode_init_once);
559         if (!v9fs_inode_cache)
560                 return -ENOMEM;
561
562         return 0;
563 }
564
565 /**
566  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
567  *
568  */
569 static void v9fs_destroy_inode_cache(void)
570 {
571         /*
572          * Make sure all delayed rcu free inodes are flushed before we
573          * destroy cache.
574          */
575         rcu_barrier();
576         kmem_cache_destroy(v9fs_inode_cache);
577 }
578
579 static int v9fs_cache_register(void)
580 {
581         int ret;
582         ret = v9fs_init_inode_cache();
583         if (ret < 0)
584                 return ret;
585 #ifdef CONFIG_9P_FSCACHE
586         return fscache_register_netfs(&v9fs_cache_netfs);
587 #else
588         return ret;
589 #endif
590 }
591
592 static void v9fs_cache_unregister(void)
593 {
594         v9fs_destroy_inode_cache();
595 #ifdef CONFIG_9P_FSCACHE
596         fscache_unregister_netfs(&v9fs_cache_netfs);
597 #endif
598 }
599
600 /**
601  * init_v9fs - Initialize module
602  *
603  */
604
605 static int __init init_v9fs(void)
606 {
607         int err;
608         pr_info("Installing v9fs 9p2000 file system support\n");
609         /* TODO: Setup list of registered trasnport modules */
610
611         err = v9fs_cache_register();
612         if (err < 0) {
613                 pr_err("Failed to register v9fs for caching\n");
614                 return err;
615         }
616
617         err = v9fs_sysfs_init();
618         if (err < 0) {
619                 pr_err("Failed to register with sysfs\n");
620                 goto out_cache;
621         }
622         err = register_filesystem(&v9fs_fs_type);
623         if (err < 0) {
624                 pr_err("Failed to register filesystem\n");
625                 goto out_sysfs_cleanup;
626         }
627
628         return 0;
629
630 out_sysfs_cleanup:
631         v9fs_sysfs_cleanup();
632
633 out_cache:
634         v9fs_cache_unregister();
635
636         return err;
637 }
638
639 /**
640  * exit_v9fs - shutdown module
641  *
642  */
643
644 static void __exit exit_v9fs(void)
645 {
646         v9fs_sysfs_cleanup();
647         v9fs_cache_unregister();
648         unregister_filesystem(&v9fs_fs_type);
649 }
650
651 module_init(init_v9fs)
652 module_exit(exit_v9fs)
653
654 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
655 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
656 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
657 MODULE_LICENSE("GPL");