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 */
get_cache_mode(char * s)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
v9fs_parse_options(struct v9fs_session_info * v9ses,char * opts)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
v9fs_session_init(struct v9fs_session_info * v9ses,const char * dev_name,char * data)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
v9fs_session_close(struct v9fs_session_info * v9ses)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
v9fs_session_cancel(struct v9fs_session_info * v9ses)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
v9fs_session_begin_cancel(struct v9fs_session_info * v9ses)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
caches_show(struct kobject * kobj,struct kobj_attribute * attr,char * buf)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
v9fs_sysfs_init(void)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
v9fs_sysfs_cleanup(void)524 static void v9fs_sysfs_cleanup(void)
525 {
526 sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
527 kobject_put(v9fs_kobj);
528 }
529
v9fs_inode_init_once(void * foo)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 */
v9fs_init_inode_cache(void)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 */
v9fs_destroy_inode_cache(void)561 static void v9fs_destroy_inode_cache(void)
562 {
563 kmem_cache_destroy(v9fs_inode_cache);
564 }
565
v9fs_cache_register(void)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
v9fs_cache_unregister(void)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
init_v9fs(void)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
598 err = v9fs_cache_register();
599 if (err < 0) {
600 pr_err("Failed to register v9fs for caching\n");
601 return err;
602 }
603
604 err = v9fs_sysfs_init();
605 if (err < 0) {
606 pr_err("Failed to register with sysfs\n");
607 goto out_cache;
608 }
609 err = register_filesystem(&v9fs_fs_type);
610 if (err < 0) {
611 pr_err("Failed to register filesystem\n");
612 goto out_sysfs_cleanup;
613 }
614
615 return 0;
616
617 out_sysfs_cleanup:
618 v9fs_sysfs_cleanup();
619
620 out_cache:
621 v9fs_cache_unregister();
622
623 return err;
624 }
625
626 /**
627 * exit_v9fs - shutdown module
628 *
629 */
630
exit_v9fs(void)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");
645