Merge branch 'for-rmk/samsung6' of git://git.fluff.org/bjdooks/linux into devel-stable
[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 <net/9p/9p.h>
33 #include <net/9p/client.h>
34 #include <net/9p/transport.h>
35 #include "v9fs.h"
36 #include "v9fs_vfs.h"
37 #include "cache.h"
38
39 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
40 static LIST_HEAD(v9fs_sessionlist);
41
42 /*
43  * Option Parsing (code inspired by NFS code)
44  *  NOTE: each transport will parse its own options
45  */
46
47 enum {
48         /* Options that take integer arguments */
49         Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
50         /* String options */
51         Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
52         /* Options that take no arguments */
53         Opt_nodevmap,
54         /* Cache options */
55         Opt_cache_loose, Opt_fscache,
56         /* Access options */
57         Opt_access,
58         /* Error token */
59         Opt_err
60 };
61
62 static const match_table_t tokens = {
63         {Opt_debug, "debug=%x"},
64         {Opt_dfltuid, "dfltuid=%u"},
65         {Opt_dfltgid, "dfltgid=%u"},
66         {Opt_afid, "afid=%u"},
67         {Opt_uname, "uname=%s"},
68         {Opt_remotename, "aname=%s"},
69         {Opt_nodevmap, "nodevmap"},
70         {Opt_cache, "cache=%s"},
71         {Opt_cache_loose, "loose"},
72         {Opt_fscache, "fscache"},
73         {Opt_cachetag, "cachetag=%s"},
74         {Opt_access, "access=%s"},
75         {Opt_err, NULL}
76 };
77
78 /**
79  * v9fs_parse_options - parse mount options into session structure
80  * @v9ses: existing v9fs session information
81  *
82  * Return 0 upon success, -ERRNO upon failure.
83  */
84
85 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
86 {
87         char *options, *tmp_options;
88         substring_t args[MAX_OPT_ARGS];
89         char *p;
90         int option = 0;
91         char *s, *e;
92         int ret = 0;
93
94         /* setup defaults */
95         v9ses->afid = ~0;
96         v9ses->debug = 0;
97         v9ses->cache = 0;
98 #ifdef CONFIG_9P_FSCACHE
99         v9ses->cachetag = NULL;
100 #endif
101
102         if (!opts)
103                 return 0;
104
105         tmp_options = kstrdup(opts, GFP_KERNEL);
106         if (!tmp_options) {
107                 ret = -ENOMEM;
108                 goto fail_option_alloc;
109         }
110         options = tmp_options;
111
112         while ((p = strsep(&options, ",")) != NULL) {
113                 int token;
114                 if (!*p)
115                         continue;
116                 token = match_token(p, tokens, args);
117                 if (token < Opt_uname) {
118                         int r = match_int(&args[0], &option);
119                         if (r < 0) {
120                                 P9_DPRINTK(P9_DEBUG_ERROR,
121                                         "integer field, but no integer?\n");
122                                 ret = r;
123                                 continue;
124                         }
125                 }
126                 switch (token) {
127                 case Opt_debug:
128                         v9ses->debug = option;
129 #ifdef CONFIG_NET_9P_DEBUG
130                         p9_debug_level = option;
131 #endif
132                         break;
133
134                 case Opt_dfltuid:
135                         v9ses->dfltuid = option;
136                         break;
137                 case Opt_dfltgid:
138                         v9ses->dfltgid = option;
139                         break;
140                 case Opt_afid:
141                         v9ses->afid = option;
142                         break;
143                 case Opt_uname:
144                         match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
145                         break;
146                 case Opt_remotename:
147                         match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
148                         break;
149                 case Opt_nodevmap:
150                         v9ses->nodev = 1;
151                         break;
152                 case Opt_cache_loose:
153                         v9ses->cache = CACHE_LOOSE;
154                         break;
155                 case Opt_fscache:
156                         v9ses->cache = CACHE_FSCACHE;
157                         break;
158                 case Opt_cachetag:
159 #ifdef CONFIG_9P_FSCACHE
160                         v9ses->cachetag = match_strdup(&args[0]);
161 #endif
162                         break;
163                 case Opt_cache:
164                         s = match_strdup(&args[0]);
165                         if (!s) {
166                                 ret = -ENOMEM;
167                                 P9_DPRINTK(P9_DEBUG_ERROR,
168                                   "problem allocating copy of cache arg\n");
169                                 goto free_and_return;
170                         }
171
172                         if (strcmp(s, "loose") == 0)
173                                 v9ses->cache = CACHE_LOOSE;
174                         else if (strcmp(s, "fscache") == 0)
175                                 v9ses->cache = CACHE_FSCACHE;
176                         else
177                                 v9ses->cache = CACHE_NONE;
178                         kfree(s);
179                         break;
180
181                 case Opt_access:
182                         s = match_strdup(&args[0]);
183                         if (!s) {
184                                 ret = -ENOMEM;
185                                 P9_DPRINTK(P9_DEBUG_ERROR,
186                                   "problem allocating copy of access arg\n");
187                                 goto free_and_return;
188                         }
189
190                         v9ses->flags &= ~V9FS_ACCESS_MASK;
191                         if (strcmp(s, "user") == 0)
192                                 v9ses->flags |= V9FS_ACCESS_USER;
193                         else if (strcmp(s, "any") == 0)
194                                 v9ses->flags |= V9FS_ACCESS_ANY;
195                         else {
196                                 v9ses->flags |= V9FS_ACCESS_SINGLE;
197                                 v9ses->uid = simple_strtoul(s, &e, 10);
198                                 if (*e != '\0')
199                                         v9ses->uid = ~0;
200                         }
201                         kfree(s);
202                         break;
203
204                 default:
205                         continue;
206                 }
207         }
208
209 free_and_return:
210         kfree(tmp_options);
211 fail_option_alloc:
212         return ret;
213 }
214
215 /**
216  * v9fs_session_init - initialize session
217  * @v9ses: session information structure
218  * @dev_name: device being mounted
219  * @data: options
220  *
221  */
222
223 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
224                   const char *dev_name, char *data)
225 {
226         int retval = -EINVAL;
227         struct p9_fid *fid;
228         int rc;
229
230         v9ses->uname = __getname();
231         if (!v9ses->uname)
232                 return ERR_PTR(-ENOMEM);
233
234         v9ses->aname = __getname();
235         if (!v9ses->aname) {
236                 __putname(v9ses->uname);
237                 return ERR_PTR(-ENOMEM);
238         }
239
240         spin_lock(&v9fs_sessionlist_lock);
241         list_add(&v9ses->slist, &v9fs_sessionlist);
242         spin_unlock(&v9fs_sessionlist_lock);
243
244         v9ses->flags = V9FS_EXTENDED | V9FS_ACCESS_USER;
245         strcpy(v9ses->uname, V9FS_DEFUSER);
246         strcpy(v9ses->aname, V9FS_DEFANAME);
247         v9ses->uid = ~0;
248         v9ses->dfltuid = V9FS_DEFUID;
249         v9ses->dfltgid = V9FS_DEFGID;
250
251         rc = v9fs_parse_options(v9ses, data);
252         if (rc < 0) {
253                 retval = rc;
254                 goto error;
255         }
256
257         v9ses->clnt = p9_client_create(dev_name, data);
258         if (IS_ERR(v9ses->clnt)) {
259                 retval = PTR_ERR(v9ses->clnt);
260                 v9ses->clnt = NULL;
261                 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
262                 goto error;
263         }
264
265         if (!v9ses->clnt->dotu)
266                 v9ses->flags &= ~V9FS_EXTENDED;
267
268         v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
269
270         /* for legacy mode, fall back to V9FS_ACCESS_ANY */
271         if (!v9fs_extended(v9ses) &&
272                 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
273
274                 v9ses->flags &= ~V9FS_ACCESS_MASK;
275                 v9ses->flags |= V9FS_ACCESS_ANY;
276                 v9ses->uid = ~0;
277         }
278
279         fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
280                                                         v9ses->aname);
281         if (IS_ERR(fid)) {
282                 retval = PTR_ERR(fid);
283                 fid = NULL;
284                 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
285                 goto error;
286         }
287
288         if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
289                 fid->uid = v9ses->uid;
290         else
291                 fid->uid = ~0;
292
293 #ifdef CONFIG_9P_FSCACHE
294         /* register the session for caching */
295         v9fs_cache_session_get_cookie(v9ses);
296 #endif
297
298         return fid;
299
300 error:
301         return ERR_PTR(retval);
302 }
303
304 /**
305  * v9fs_session_close - shutdown a session
306  * @v9ses: session information structure
307  *
308  */
309
310 void v9fs_session_close(struct v9fs_session_info *v9ses)
311 {
312         if (v9ses->clnt) {
313                 p9_client_destroy(v9ses->clnt);
314                 v9ses->clnt = NULL;
315         }
316
317 #ifdef CONFIG_9P_FSCACHE
318         if (v9ses->fscache) {
319                 v9fs_cache_session_put_cookie(v9ses);
320                 kfree(v9ses->cachetag);
321         }
322 #endif
323         __putname(v9ses->uname);
324         __putname(v9ses->aname);
325
326         spin_lock(&v9fs_sessionlist_lock);
327         list_del(&v9ses->slist);
328         spin_unlock(&v9fs_sessionlist_lock);
329 }
330
331 /**
332  * v9fs_session_cancel - terminate a session
333  * @v9ses: session to terminate
334  *
335  * mark transport as disconnected and cancel all pending requests.
336  */
337
338 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
339         P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
340         p9_client_disconnect(v9ses->clnt);
341 }
342
343 extern int v9fs_error_init(void);
344
345 static struct kobject *v9fs_kobj;
346
347 #ifdef CONFIG_9P_FSCACHE
348 /**
349  * caches_show - list caches associated with a session
350  *
351  * Returns the size of buffer written.
352  */
353
354 static ssize_t caches_show(struct kobject *kobj,
355                            struct kobj_attribute *attr,
356                            char *buf)
357 {
358         ssize_t n = 0, count = 0, limit = PAGE_SIZE;
359         struct v9fs_session_info *v9ses;
360
361         spin_lock(&v9fs_sessionlist_lock);
362         list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
363                 if (v9ses->cachetag) {
364                         n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
365                         if (n < 0) {
366                                 count = n;
367                                 break;
368                         }
369
370                         count += n;
371                         limit -= n;
372                 }
373         }
374
375         spin_unlock(&v9fs_sessionlist_lock);
376         return count;
377 }
378
379 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
380 #endif /* CONFIG_9P_FSCACHE */
381
382 static struct attribute *v9fs_attrs[] = {
383 #ifdef CONFIG_9P_FSCACHE
384         &v9fs_attr_cache.attr,
385 #endif
386         NULL,
387 };
388
389 static struct attribute_group v9fs_attr_group = {
390         .attrs = v9fs_attrs,
391 };
392
393 /**
394  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
395  *
396  */
397
398 static int v9fs_sysfs_init(void)
399 {
400         v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
401         if (!v9fs_kobj)
402                 return -ENOMEM;
403
404         if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
405                 kobject_put(v9fs_kobj);
406                 return -ENOMEM;
407         }
408
409         return 0;
410 }
411
412 /**
413  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
414  *
415  */
416
417 static void v9fs_sysfs_cleanup(void)
418 {
419         sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
420         kobject_put(v9fs_kobj);
421 }
422
423 /**
424  * init_v9fs - Initialize module
425  *
426  */
427
428 static int __init init_v9fs(void)
429 {
430         int err;
431         printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
432         /* TODO: Setup list of registered trasnport modules */
433         err = register_filesystem(&v9fs_fs_type);
434         if (err < 0) {
435                 printk(KERN_ERR "Failed to register filesystem\n");
436                 return err;
437         }
438
439         err = v9fs_cache_register();
440         if (err < 0) {
441                 printk(KERN_ERR "Failed to register v9fs for caching\n");
442                 goto out_fs_unreg;
443         }
444
445         err = v9fs_sysfs_init();
446         if (err < 0) {
447                 printk(KERN_ERR "Failed to register with sysfs\n");
448                 goto out_sysfs_cleanup;
449         }
450
451         return 0;
452
453 out_sysfs_cleanup:
454         v9fs_sysfs_cleanup();
455
456 out_fs_unreg:
457         unregister_filesystem(&v9fs_fs_type);
458
459         return err;
460 }
461
462 /**
463  * exit_v9fs - shutdown module
464  *
465  */
466
467 static void __exit exit_v9fs(void)
468 {
469         v9fs_sysfs_cleanup();
470         v9fs_cache_unregister();
471         unregister_filesystem(&v9fs_fs_type);
472 }
473
474 module_init(init_v9fs)
475 module_exit(exit_v9fs)
476
477 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
478 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
479 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
480 MODULE_LICENSE("GPL");