/fs/9p/v9fs.c
C | 624 lines | 434 code | 83 blank | 107 comment | 57 complexity | f948883d0bb5c03fb7ea0c1412f57c1b MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
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
40static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
41static LIST_HEAD(v9fs_sessionlist);
42struct 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
49enum {
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
64static 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 */
82static 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
107static 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;
136 if (!*p)
137 continue;
138 token = match_token(p, tokens, args);
139 if (token < Opt_uname) {
140 int r = match_int(&args[0], &option);
141 if (r < 0) {
142 P9_DPRINTK(P9_DEBUG_ERROR,
143 "integer field, but no integer?\n");
144 ret = r;
145 continue;
146 }
147 }
148 switch (token) {
149 case Opt_debug:
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 v9ses->dfltuid = option;
158 break;
159 case Opt_dfltgid:
160 v9ses->dfltgid = option;
161 break;
162 case Opt_afid:
163 v9ses->afid = option;
164 break;
165 case Opt_uname:
166 match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
167 break;
168 case Opt_remotename:
169 match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
170 break;
171 case Opt_nodevmap:
172 v9ses->nodev = 1;
173 break;
174 case Opt_cache_loose:
175 v9ses->cache = CACHE_LOOSE;
176 break;
177 case Opt_fscache:
178 v9ses->cache = CACHE_FSCACHE;
179 break;
180 case Opt_cachetag:
181#ifdef CONFIG_9P_FSCACHE
182 v9ses->cachetag = match_strdup(&args[0]);
183#endif
184 break;
185 case Opt_cache:
186 s = match_strdup(&args[0]);
187 if (!s) {
188 ret = -ENOMEM;
189 P9_DPRINTK(P9_DEBUG_ERROR,
190 "problem allocating copy of cache arg\n");
191 goto free_and_return;
192 }
193 ret = get_cache_mode(s);
194 if (ret == -EINVAL) {
195 kfree(s);
196 goto free_and_return;
197 }
198
199 v9ses->cache = ret;
200 kfree(s);
201 break;
202
203 case Opt_access:
204 s = match_strdup(&args[0]);
205 if (!s) {
206 ret = -ENOMEM;
207 P9_DPRINTK(P9_DEBUG_ERROR,
208 "problem allocating copy of access arg\n");
209 goto free_and_return;
210 }
211
212 v9ses->flags &= ~V9FS_ACCESS_MASK;
213 if (strcmp(s, "user") == 0)
214 v9ses->flags |= V9FS_ACCESS_USER;
215 else if (strcmp(s, "any") == 0)
216 v9ses->flags |= V9FS_ACCESS_ANY;
217 else if (strcmp(s, "client") == 0) {
218 v9ses->flags |= V9FS_ACCESS_CLIENT;
219 } else {
220 v9ses->flags |= V9FS_ACCESS_SINGLE;
221 v9ses->uid = simple_strtoul(s, &e, 10);
222 if (*e != '\0') {
223 ret = -EINVAL;
224 printk(KERN_INFO "9p: Unknown access "
225 "argument %s.\n", s);
226 kfree(s);
227 goto free_and_return;
228 }
229 }
230
231 kfree(s);
232 break;
233
234 case Opt_posixacl:
235#ifdef CONFIG_9P_FS_POSIX_ACL
236 v9ses->flags |= V9FS_POSIX_ACL;
237#else
238 P9_DPRINTK(P9_DEBUG_ERROR,
239 "Not defined CONFIG_9P_FS_POSIX_ACL. "
240 "Ignoring posixacl option\n");
241#endif
242 break;
243
244 default:
245 continue;
246 }
247 }
248
249free_and_return:
250 kfree(tmp_options);
251fail_option_alloc:
252 return ret;
253}
254
255/**
256 * v9fs_session_init - initialize session
257 * @v9ses: session information structure
258 * @dev_name: device being mounted
259 * @data: options
260 *
261 */
262
263struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
264 const char *dev_name, char *data)
265{
266 int retval = -EINVAL;
267 struct p9_fid *fid;
268 int rc;
269
270 v9ses->uname = __getname();
271 if (!v9ses->uname)
272 return ERR_PTR(-ENOMEM);
273
274 v9ses->aname = __getname();
275 if (!v9ses->aname) {
276 __putname(v9ses->uname);
277 return ERR_PTR(-ENOMEM);
278 }
279 init_rwsem(&v9ses->rename_sem);
280
281 rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
282 if (rc) {
283 __putname(v9ses->aname);
284 __putname(v9ses->uname);
285 return ERR_PTR(rc);
286 }
287
288 spin_lock(&v9fs_sessionlist_lock);
289 list_add(&v9ses->slist, &v9fs_sessionlist);
290 spin_unlock(&v9fs_sessionlist_lock);
291
292 strcpy(v9ses->uname, V9FS_DEFUSER);
293 strcpy(v9ses->aname, V9FS_DEFANAME);
294 v9ses->uid = ~0;
295 v9ses->dfltuid = V9FS_DEFUID;
296 v9ses->dfltgid = V9FS_DEFGID;
297
298 v9ses->clnt = p9_client_create(dev_name, data);
299 if (IS_ERR(v9ses->clnt)) {
300 retval = PTR_ERR(v9ses->clnt);
301 v9ses->clnt = NULL;
302 P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
303 goto error;
304 }
305
306 v9ses->flags = V9FS_ACCESS_USER;
307
308 if (p9_is_proto_dotl(v9ses->clnt)) {
309 v9ses->flags = V9FS_ACCESS_CLIENT;
310 v9ses->flags |= V9FS_PROTO_2000L;
311 } else if (p9_is_proto_dotu(v9ses->clnt)) {
312 v9ses->flags |= V9FS_PROTO_2000U;
313 }
314
315 rc = v9fs_parse_options(v9ses, data);
316 if (rc < 0) {
317 retval = rc;
318 goto error;
319 }
320
321 v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
322
323 if (!v9fs_proto_dotl(v9ses) &&
324 ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
325 /*
326 * We support ACCESS_CLIENT only for dotl.
327 * Fall back to ACCESS_USER
328 */
329 v9ses->flags &= ~V9FS_ACCESS_MASK;
330 v9ses->flags |= V9FS_ACCESS_USER;
331 }
332 /*FIXME !! */
333 /* for legacy mode, fall back to V9FS_ACCESS_ANY */
334 if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
335 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
336
337 v9ses->flags &= ~V9FS_ACCESS_MASK;
338 v9ses->flags |= V9FS_ACCESS_ANY;
339 v9ses->uid = ~0;
340 }
341 if (!v9fs_proto_dotl(v9ses) ||
342 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
343 /*
344 * We support ACL checks on clinet only if the protocol is
345 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
346 */
347 v9ses->flags &= ~V9FS_ACL_MASK;
348 }
349
350 fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
351 v9ses->aname);
352 if (IS_ERR(fid)) {
353 retval = PTR_ERR(fid);
354 fid = NULL;
355 P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
356 goto error;
357 }
358
359 if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
360 fid->uid = v9ses->uid;
361 else
362 fid->uid = ~0;
363
364#ifdef CONFIG_9P_FSCACHE
365 /* register the session for caching */
366 v9fs_cache_session_get_cookie(v9ses);
367#endif
368
369 return fid;
370
371error:
372 bdi_destroy(&v9ses->bdi);
373 return ERR_PTR(retval);
374}
375
376/**
377 * v9fs_session_close - shutdown a session
378 * @v9ses: session information structure
379 *
380 */
381
382void v9fs_session_close(struct v9fs_session_info *v9ses)
383{
384 if (v9ses->clnt) {
385 p9_client_destroy(v9ses->clnt);
386 v9ses->clnt = NULL;
387 }
388
389#ifdef CONFIG_9P_FSCACHE
390 if (v9ses->fscache) {
391 v9fs_cache_session_put_cookie(v9ses);
392 kfree(v9ses->cachetag);
393 }
394#endif
395 __putname(v9ses->uname);
396 __putname(v9ses->aname);
397
398 bdi_destroy(&v9ses->bdi);
399
400 spin_lock(&v9fs_sessionlist_lock);
401 list_del(&v9ses->slist);
402 spin_unlock(&v9fs_sessionlist_lock);
403}
404
405/**
406 * v9fs_session_cancel - terminate a session
407 * @v9ses: session to terminate
408 *
409 * mark transport as disconnected and cancel all pending requests.
410 */
411
412void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
413 P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
414 p9_client_disconnect(v9ses->clnt);
415}
416
417/**
418 * v9fs_session_begin_cancel - Begin terminate of a session
419 * @v9ses: session to terminate
420 *
421 * After this call we don't allow any request other than clunk.
422 */
423
424void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
425{
426 P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
427 p9_client_begin_disconnect(v9ses->clnt);
428}
429
430extern int v9fs_error_init(void);
431
432static struct kobject *v9fs_kobj;
433
434#ifdef CONFIG_9P_FSCACHE
435/**
436 * caches_show - list caches associated with a session
437 *
438 * Returns the size of buffer written.
439 */
440
441static ssize_t caches_show(struct kobject *kobj,
442 struct kobj_attribute *attr,
443 char *buf)
444{
445 ssize_t n = 0, count = 0, limit = PAGE_SIZE;
446 struct v9fs_session_info *v9ses;
447
448 spin_lock(&v9fs_sessionlist_lock);
449 list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
450 if (v9ses->cachetag) {
451 n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
452 if (n < 0) {
453 count = n;
454 break;
455 }
456
457 count += n;
458 limit -= n;
459 }
460 }
461
462 spin_unlock(&v9fs_sessionlist_lock);
463 return count;
464}
465
466static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
467#endif /* CONFIG_9P_FSCACHE */
468
469static struct attribute *v9fs_attrs[] = {
470#ifdef CONFIG_9P_FSCACHE
471 &v9fs_attr_cache.attr,
472#endif
473 NULL,
474};
475
476static struct attribute_group v9fs_attr_group = {
477 .attrs = v9fs_attrs,
478};
479
480/**
481 * v9fs_sysfs_init - Initialize the v9fs sysfs interface
482 *
483 */
484
485static int v9fs_sysfs_init(void)
486{
487 v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
488 if (!v9fs_kobj)
489 return -ENOMEM;
490
491 if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
492 kobject_put(v9fs_kobj);
493 return -ENOMEM;
494 }
495
496 return 0;
497}
498
499/**
500 * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
501 *
502 */
503
504static void v9fs_sysfs_cleanup(void)
505{
506 sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
507 kobject_put(v9fs_kobj);
508}
509
510static void v9fs_inode_init_once(void *foo)
511{
512 struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
513#ifdef CONFIG_9P_FSCACHE
514 v9inode->fscache = NULL;
515#endif
516 memset(&v9inode->qid, 0, sizeof(v9inode->qid));
517 inode_init_once(&v9inode->vfs_inode);
518}
519
520/**
521 * v9fs_init_inode_cache - initialize a cache for 9P
522 * Returns 0 on success.
523 */
524static int v9fs_init_inode_cache(void)
525{
526 v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
527 sizeof(struct v9fs_inode),
528 0, (SLAB_RECLAIM_ACCOUNT|
529 SLAB_MEM_SPREAD),
530 v9fs_inode_init_once);
531 if (!v9fs_inode_cache)
532 return -ENOMEM;
533
534 return 0;
535}
536
537/**
538 * v9fs_destroy_inode_cache - destroy the cache of 9P inode
539 *
540 */
541static void v9fs_destroy_inode_cache(void)
542{
543 kmem_cache_destroy(v9fs_inode_cache);
544}
545
546static int v9fs_cache_register(void)
547{
548 int ret;
549 ret = v9fs_init_inode_cache();
550 if (ret < 0)
551 return ret;
552#ifdef CONFIG_9P_FSCACHE
553 return fscache_register_netfs(&v9fs_cache_netfs);
554#else
555 return ret;
556#endif
557}
558
559static void v9fs_cache_unregister(void)
560{
561 v9fs_destroy_inode_cache();
562#ifdef CONFIG_9P_FSCACHE
563 fscache_unregister_netfs(&v9fs_cache_netfs);
564#endif
565}
566
567/**
568 * init_v9fs - Initialize module
569 *
570 */
571
572static int __init init_v9fs(void)
573{
574 int err;
575 printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
576 /* TODO: Setup list of registered trasnport modules */
577 err = register_filesystem(&v9fs_fs_type);
578 if (err < 0) {
579 printk(KERN_ERR "Failed to register filesystem\n");
580 return err;
581 }
582
583 err = v9fs_cache_register();
584 if (err < 0) {
585 printk(KERN_ERR "Failed to register v9fs for caching\n");
586 goto out_fs_unreg;
587 }
588
589 err = v9fs_sysfs_init();
590 if (err < 0) {
591 printk(KERN_ERR "Failed to register with sysfs\n");
592 goto out_sysfs_cleanup;
593 }
594
595 return 0;
596
597out_sysfs_cleanup:
598 v9fs_sysfs_cleanup();
599
600out_fs_unreg:
601 unregister_filesystem(&v9fs_fs_type);
602
603 return err;
604}
605
606/**
607 * exit_v9fs - shutdown module
608 *
609 */
610
611static void __exit exit_v9fs(void)
612{
613 v9fs_sysfs_cleanup();
614 v9fs_cache_unregister();
615 unregister_filesystem(&v9fs_fs_type);
616}
617
618module_init(init_v9fs)
619module_exit(exit_v9fs)
620
621MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
622MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
623MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
624MODULE_LICENSE("GPL");