xref: /openbmc/linux/fs/9p/v9fs.c (revision 09bae3b6) 
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/cred.h>
33 #include <linux/parser.h>
34 #include <linux/idr.h>
35 #include <linux/slab.h>
36 #include <linux/seq_file.h>
37 #include <net/9p/9p.h>
38 #include <net/9p/client.h>
39 #include <net/9p/transport.h>
40 #include "v9fs.h"
41 #include "v9fs_vfs.h"
42 #include "cache.h"
43 
44 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
45 static LIST_HEAD(v9fs_sessionlist);
46 struct kmem_cache *v9fs_inode_cache;
47 
48 /*
49  * Option Parsing (code inspired by NFS code)
50  *  NOTE: each transport will parse its own options
51  */
52 
53 enum {
54 	/* Options that take integer arguments */
55 	Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
56 	/* String options */
57 	Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
58 	/* Options that take no arguments */
59 	Opt_nodevmap,
60 	/* Cache options */
61 	Opt_cache_loose, Opt_fscache, Opt_mmap,
62 	/* Access options */
63 	Opt_access, Opt_posixacl,
64 	/* Error token */
65 	Opt_err
66 };
67 
68 static const match_table_t tokens = {
69 	{Opt_debug, "debug=%x"},
70 	{Opt_dfltuid, "dfltuid=%u"},
71 	{Opt_dfltgid, "dfltgid=%u"},
72 	{Opt_afid, "afid=%u"},
73 	{Opt_uname, "uname=%s"},
74 	{Opt_remotename, "aname=%s"},
75 	{Opt_nodevmap, "nodevmap"},
76 	{Opt_cache, "cache=%s"},
77 	{Opt_cache_loose, "loose"},
78 	{Opt_fscache, "fscache"},
79 	{Opt_mmap, "mmap"},
80 	{Opt_cachetag, "cachetag=%s"},
81 	{Opt_access, "access=%s"},
82 	{Opt_posixacl, "posixacl"},
83 	{Opt_err, NULL}
84 };
85 
86 static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
87 	[CACHE_NONE]	= "none",
88 	[CACHE_MMAP]	= "mmap",
89 	[CACHE_LOOSE]	= "loose",
90 	[CACHE_FSCACHE]	= "fscache",
91 };
92 
93 /* Interpret mount options for cache mode */
94 static int get_cache_mode(char *s)
95 {
96 	int version = -EINVAL;
97 
98 	if (!strcmp(s, "loose")) {
99 		version = CACHE_LOOSE;
100 		p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
101 	} else if (!strcmp(s, "fscache")) {
102 		version = CACHE_FSCACHE;
103 		p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
104 	} else if (!strcmp(s, "mmap")) {
105 		version = CACHE_MMAP;
106 		p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
107 	} else if (!strcmp(s, "none")) {
108 		version = CACHE_NONE;
109 		p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
110 	} else
111 		pr_info("Unknown Cache mode %s\n", s);
112 	return version;
113 }
114 
115 /*
116  * Display the mount options in /proc/mounts.
117  */
118 int v9fs_show_options(struct seq_file *m, struct dentry *root)
119 {
120 	struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
121 
122 	if (v9ses->debug)
123 		seq_printf(m, ",debug=%x", v9ses->debug);
124 	if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
125 		seq_printf(m, ",dfltuid=%u",
126 			   from_kuid_munged(&init_user_ns, v9ses->dfltuid));
127 	if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
128 		seq_printf(m, ",dfltgid=%u",
129 			   from_kgid_munged(&init_user_ns, v9ses->dfltgid));
130 	if (v9ses->afid != ~0)
131 		seq_printf(m, ",afid=%u", v9ses->afid);
132 	if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
133 		seq_printf(m, ",uname=%s", v9ses->uname);
134 	if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
135 		seq_printf(m, ",aname=%s", v9ses->aname);
136 	if (v9ses->nodev)
137 		seq_puts(m, ",nodevmap");
138 	if (v9ses->cache)
139 		seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
140 #ifdef CONFIG_9P_FSCACHE
141 	if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
142 		seq_printf(m, ",cachetag=%s", v9ses->cachetag);
143 #endif
144 
145 	switch (v9ses->flags & V9FS_ACCESS_MASK) {
146 	case V9FS_ACCESS_USER:
147 		seq_puts(m, ",access=user");
148 		break;
149 	case V9FS_ACCESS_ANY:
150 		seq_puts(m, ",access=any");
151 		break;
152 	case V9FS_ACCESS_CLIENT:
153 		seq_puts(m, ",access=client");
154 		break;
155 	case V9FS_ACCESS_SINGLE:
156 		seq_printf(m, ",access=%u",
157 			   from_kuid_munged(&init_user_ns, v9ses->uid));
158 		break;
159 	}
160 
161 	if (v9ses->flags & V9FS_POSIX_ACL)
162 		seq_puts(m, ",posixacl");
163 
164 	return p9_show_client_options(m, v9ses->clnt);
165 }
166 
167 /**
168  * v9fs_parse_options - parse mount options into session structure
169  * @v9ses: existing v9fs session information
170  *
171  * Return 0 upon success, -ERRNO upon failure.
172  */
173 
174 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
175 {
176 	char *options, *tmp_options;
177 	substring_t args[MAX_OPT_ARGS];
178 	char *p;
179 	int option = 0;
180 	char *s, *e;
181 	int ret = 0;
182 
183 	/* setup defaults */
184 	v9ses->afid = ~0;
185 	v9ses->debug = 0;
186 	v9ses->cache = CACHE_NONE;
187 #ifdef CONFIG_9P_FSCACHE
188 	v9ses->cachetag = NULL;
189 #endif
190 
191 	if (!opts)
192 		return 0;
193 
194 	tmp_options = kstrdup(opts, GFP_KERNEL);
195 	if (!tmp_options) {
196 		ret = -ENOMEM;
197 		goto fail_option_alloc;
198 	}
199 	options = tmp_options;
200 
201 	while ((p = strsep(&options, ",")) != NULL) {
202 		int token, r;
203 		if (!*p)
204 			continue;
205 		token = match_token(p, tokens, args);
206 		switch (token) {
207 		case Opt_debug:
208 			r = match_int(&args[0], &option);
209 			if (r < 0) {
210 				p9_debug(P9_DEBUG_ERROR,
211 					 "integer field, but no integer?\n");
212 				ret = r;
213 			} else {
214 				v9ses->debug = option;
215 #ifdef CONFIG_NET_9P_DEBUG
216 				p9_debug_level = option;
217 #endif
218 			}
219 			break;
220 
221 		case Opt_dfltuid:
222 			r = match_int(&args[0], &option);
223 			if (r < 0) {
224 				p9_debug(P9_DEBUG_ERROR,
225 					 "integer field, but no integer?\n");
226 				ret = r;
227 				continue;
228 			}
229 			v9ses->dfltuid = make_kuid(current_user_ns(), option);
230 			if (!uid_valid(v9ses->dfltuid)) {
231 				p9_debug(P9_DEBUG_ERROR,
232 					 "uid field, but not a uid?\n");
233 				ret = -EINVAL;
234 			}
235 			break;
236 		case Opt_dfltgid:
237 			r = match_int(&args[0], &option);
238 			if (r < 0) {
239 				p9_debug(P9_DEBUG_ERROR,
240 					 "integer field, but no integer?\n");
241 				ret = r;
242 				continue;
243 			}
244 			v9ses->dfltgid = make_kgid(current_user_ns(), option);
245 			if (!gid_valid(v9ses->dfltgid)) {
246 				p9_debug(P9_DEBUG_ERROR,
247 					 "gid field, but not a gid?\n");
248 				ret = -EINVAL;
249 			}
250 			break;
251 		case Opt_afid:
252 			r = match_int(&args[0], &option);
253 			if (r < 0) {
254 				p9_debug(P9_DEBUG_ERROR,
255 					 "integer field, but no integer?\n");
256 				ret = r;
257 			} else {
258 				v9ses->afid = option;
259 			}
260 			break;
261 		case Opt_uname:
262 			kfree(v9ses->uname);
263 			v9ses->uname = match_strdup(&args[0]);
264 			if (!v9ses->uname) {
265 				ret = -ENOMEM;
266 				goto free_and_return;
267 			}
268 			break;
269 		case Opt_remotename:
270 			kfree(v9ses->aname);
271 			v9ses->aname = match_strdup(&args[0]);
272 			if (!v9ses->aname) {
273 				ret = -ENOMEM;
274 				goto free_and_return;
275 			}
276 			break;
277 		case Opt_nodevmap:
278 			v9ses->nodev = 1;
279 			break;
280 		case Opt_cache_loose:
281 			v9ses->cache = CACHE_LOOSE;
282 			break;
283 		case Opt_fscache:
284 			v9ses->cache = CACHE_FSCACHE;
285 			break;
286 		case Opt_mmap:
287 			v9ses->cache = CACHE_MMAP;
288 			break;
289 		case Opt_cachetag:
290 #ifdef CONFIG_9P_FSCACHE
291 			kfree(v9ses->cachetag);
292 			v9ses->cachetag = match_strdup(&args[0]);
293 			if (!v9ses->cachetag) {
294 				ret = -ENOMEM;
295 				goto free_and_return;
296 			}
297 #endif
298 			break;
299 		case Opt_cache:
300 			s = match_strdup(&args[0]);
301 			if (!s) {
302 				ret = -ENOMEM;
303 				p9_debug(P9_DEBUG_ERROR,
304 					 "problem allocating copy of cache arg\n");
305 				goto free_and_return;
306 			}
307 			r = get_cache_mode(s);
308 			if (r < 0)
309 				ret = r;
310 			else
311 				v9ses->cache = r;
312 
313 			kfree(s);
314 			break;
315 
316 		case Opt_access:
317 			s = match_strdup(&args[0]);
318 			if (!s) {
319 				ret = -ENOMEM;
320 				p9_debug(P9_DEBUG_ERROR,
321 					 "problem allocating copy of access arg\n");
322 				goto free_and_return;
323 			}
324 
325 			v9ses->flags &= ~V9FS_ACCESS_MASK;
326 			if (strcmp(s, "user") == 0)
327 				v9ses->flags |= V9FS_ACCESS_USER;
328 			else if (strcmp(s, "any") == 0)
329 				v9ses->flags |= V9FS_ACCESS_ANY;
330 			else if (strcmp(s, "client") == 0) {
331 				v9ses->flags |= V9FS_ACCESS_CLIENT;
332 			} else {
333 				uid_t uid;
334 				v9ses->flags |= V9FS_ACCESS_SINGLE;
335 				uid = simple_strtoul(s, &e, 10);
336 				if (*e != '\0') {
337 					ret = -EINVAL;
338 					pr_info("Unknown access argument %s\n",
339 						s);
340 					kfree(s);
341 					continue;
342 				}
343 				v9ses->uid = make_kuid(current_user_ns(), uid);
344 				if (!uid_valid(v9ses->uid)) {
345 					ret = -EINVAL;
346 					pr_info("Unknown uid %s\n", s);
347 				}
348 			}
349 
350 			kfree(s);
351 			break;
352 
353 		case Opt_posixacl:
354 #ifdef CONFIG_9P_FS_POSIX_ACL
355 			v9ses->flags |= V9FS_POSIX_ACL;
356 #else
357 			p9_debug(P9_DEBUG_ERROR,
358 				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
359 #endif
360 			break;
361 
362 		default:
363 			continue;
364 		}
365 	}
366 
367 free_and_return:
368 	kfree(tmp_options);
369 fail_option_alloc:
370 	return ret;
371 }
372 
373 /**
374  * v9fs_session_init - initialize session
375  * @v9ses: session information structure
376  * @dev_name: device being mounted
377  * @data: options
378  *
379  */
380 
381 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
382 		  const char *dev_name, char *data)
383 {
384 	struct p9_fid *fid;
385 	int rc = -ENOMEM;
386 
387 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
388 	if (!v9ses->uname)
389 		goto err_names;
390 
391 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
392 	if (!v9ses->aname)
393 		goto err_names;
394 	init_rwsem(&v9ses->rename_sem);
395 
396 	v9ses->uid = INVALID_UID;
397 	v9ses->dfltuid = V9FS_DEFUID;
398 	v9ses->dfltgid = V9FS_DEFGID;
399 
400 	v9ses->clnt = p9_client_create(dev_name, data);
401 	if (IS_ERR(v9ses->clnt)) {
402 		rc = PTR_ERR(v9ses->clnt);
403 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
404 		goto err_names;
405 	}
406 
407 	v9ses->flags = V9FS_ACCESS_USER;
408 
409 	if (p9_is_proto_dotl(v9ses->clnt)) {
410 		v9ses->flags = V9FS_ACCESS_CLIENT;
411 		v9ses->flags |= V9FS_PROTO_2000L;
412 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
413 		v9ses->flags |= V9FS_PROTO_2000U;
414 	}
415 
416 	rc = v9fs_parse_options(v9ses, data);
417 	if (rc < 0)
418 		goto err_clnt;
419 
420 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
421 
422 	if (!v9fs_proto_dotl(v9ses) &&
423 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
424 		/*
425 		 * We support ACCESS_CLIENT only for dotl.
426 		 * Fall back to ACCESS_USER
427 		 */
428 		v9ses->flags &= ~V9FS_ACCESS_MASK;
429 		v9ses->flags |= V9FS_ACCESS_USER;
430 	}
431 	/*FIXME !! */
432 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
433 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
434 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
435 
436 		v9ses->flags &= ~V9FS_ACCESS_MASK;
437 		v9ses->flags |= V9FS_ACCESS_ANY;
438 		v9ses->uid = INVALID_UID;
439 	}
440 	if (!v9fs_proto_dotl(v9ses) ||
441 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
442 		/*
443 		 * We support ACL checks on clinet only if the protocol is
444 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
445 		 */
446 		v9ses->flags &= ~V9FS_ACL_MASK;
447 	}
448 
449 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
450 							v9ses->aname);
451 	if (IS_ERR(fid)) {
452 		rc = PTR_ERR(fid);
453 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
454 		goto err_clnt;
455 	}
456 
457 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
458 		fid->uid = v9ses->uid;
459 	else
460 		fid->uid = INVALID_UID;
461 
462 #ifdef CONFIG_9P_FSCACHE
463 	/* register the session for caching */
464 	v9fs_cache_session_get_cookie(v9ses);
465 #endif
466 	spin_lock(&v9fs_sessionlist_lock);
467 	list_add(&v9ses->slist, &v9fs_sessionlist);
468 	spin_unlock(&v9fs_sessionlist_lock);
469 
470 	return fid;
471 
472 err_clnt:
473 #ifdef CONFIG_9P_FSCACHE
474 	kfree(v9ses->cachetag);
475 #endif
476 	p9_client_destroy(v9ses->clnt);
477 err_names:
478 	kfree(v9ses->uname);
479 	kfree(v9ses->aname);
480 	return ERR_PTR(rc);
481 }
482 
483 /**
484  * v9fs_session_close - shutdown a session
485  * @v9ses: session information structure
486  *
487  */
488 
489 void v9fs_session_close(struct v9fs_session_info *v9ses)
490 {
491 	if (v9ses->clnt) {
492 		p9_client_destroy(v9ses->clnt);
493 		v9ses->clnt = NULL;
494 	}
495 
496 #ifdef CONFIG_9P_FSCACHE
497 	if (v9ses->fscache) {
498 		v9fs_cache_session_put_cookie(v9ses);
499 		kfree(v9ses->cachetag);
500 	}
501 #endif
502 	kfree(v9ses->uname);
503 	kfree(v9ses->aname);
504 
505 	spin_lock(&v9fs_sessionlist_lock);
506 	list_del(&v9ses->slist);
507 	spin_unlock(&v9fs_sessionlist_lock);
508 }
509 
510 /**
511  * v9fs_session_cancel - terminate a session
512  * @v9ses: session to terminate
513  *
514  * mark transport as disconnected and cancel all pending requests.
515  */
516 
517 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
518 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
519 	p9_client_disconnect(v9ses->clnt);
520 }
521 
522 /**
523  * v9fs_session_begin_cancel - Begin terminate of a session
524  * @v9ses: session to terminate
525  *
526  * After this call we don't allow any request other than clunk.
527  */
528 
529 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
530 {
531 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
532 	p9_client_begin_disconnect(v9ses->clnt);
533 }
534 
535 extern int v9fs_error_init(void);
536 
537 static struct kobject *v9fs_kobj;
538 
539 #ifdef CONFIG_9P_FSCACHE
540 /**
541  * caches_show - list caches associated with a session
542  *
543  * Returns the size of buffer written.
544  */
545 
546 static ssize_t caches_show(struct kobject *kobj,
547 			   struct kobj_attribute *attr,
548 			   char *buf)
549 {
550 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
551 	struct v9fs_session_info *v9ses;
552 
553 	spin_lock(&v9fs_sessionlist_lock);
554 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
555 		if (v9ses->cachetag) {
556 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
557 			if (n < 0) {
558 				count = n;
559 				break;
560 			}
561 
562 			count += n;
563 			limit -= n;
564 		}
565 	}
566 
567 	spin_unlock(&v9fs_sessionlist_lock);
568 	return count;
569 }
570 
571 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
572 #endif /* CONFIG_9P_FSCACHE */
573 
574 static struct attribute *v9fs_attrs[] = {
575 #ifdef CONFIG_9P_FSCACHE
576 	&v9fs_attr_cache.attr,
577 #endif
578 	NULL,
579 };
580 
581 static struct attribute_group v9fs_attr_group = {
582 	.attrs = v9fs_attrs,
583 };
584 
585 /**
586  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
587  *
588  */
589 
590 static int __init v9fs_sysfs_init(void)
591 {
592 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
593 	if (!v9fs_kobj)
594 		return -ENOMEM;
595 
596 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
597 		kobject_put(v9fs_kobj);
598 		return -ENOMEM;
599 	}
600 
601 	return 0;
602 }
603 
604 /**
605  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
606  *
607  */
608 
609 static void v9fs_sysfs_cleanup(void)
610 {
611 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
612 	kobject_put(v9fs_kobj);
613 }
614 
615 static void v9fs_inode_init_once(void *foo)
616 {
617 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
618 #ifdef CONFIG_9P_FSCACHE
619 	v9inode->fscache = NULL;
620 #endif
621 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
622 	inode_init_once(&v9inode->vfs_inode);
623 }
624 
625 /**
626  * v9fs_init_inode_cache - initialize a cache for 9P
627  * Returns 0 on success.
628  */
629 static int v9fs_init_inode_cache(void)
630 {
631 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
632 					  sizeof(struct v9fs_inode),
633 					  0, (SLAB_RECLAIM_ACCOUNT|
634 					      SLAB_MEM_SPREAD|SLAB_ACCOUNT),
635 					  v9fs_inode_init_once);
636 	if (!v9fs_inode_cache)
637 		return -ENOMEM;
638 
639 	return 0;
640 }
641 
642 /**
643  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
644  *
645  */
646 static void v9fs_destroy_inode_cache(void)
647 {
648 	/*
649 	 * Make sure all delayed rcu free inodes are flushed before we
650 	 * destroy cache.
651 	 */
652 	rcu_barrier();
653 	kmem_cache_destroy(v9fs_inode_cache);
654 }
655 
656 static int v9fs_cache_register(void)
657 {
658 	int ret;
659 	ret = v9fs_init_inode_cache();
660 	if (ret < 0)
661 		return ret;
662 #ifdef CONFIG_9P_FSCACHE
663 	ret = fscache_register_netfs(&v9fs_cache_netfs);
664 	if (ret < 0)
665 		v9fs_destroy_inode_cache();
666 #endif
667 	return ret;
668 }
669 
670 static void v9fs_cache_unregister(void)
671 {
672 	v9fs_destroy_inode_cache();
673 #ifdef CONFIG_9P_FSCACHE
674 	fscache_unregister_netfs(&v9fs_cache_netfs);
675 #endif
676 }
677 
678 /**
679  * init_v9fs - Initialize module
680  *
681  */
682 
683 static int __init init_v9fs(void)
684 {
685 	int err;
686 	pr_info("Installing v9fs 9p2000 file system support\n");
687 	/* TODO: Setup list of registered trasnport modules */
688 
689 	err = v9fs_cache_register();
690 	if (err < 0) {
691 		pr_err("Failed to register v9fs for caching\n");
692 		return err;
693 	}
694 
695 	err = v9fs_sysfs_init();
696 	if (err < 0) {
697 		pr_err("Failed to register with sysfs\n");
698 		goto out_cache;
699 	}
700 	err = register_filesystem(&v9fs_fs_type);
701 	if (err < 0) {
702 		pr_err("Failed to register filesystem\n");
703 		goto out_sysfs_cleanup;
704 	}
705 
706 	return 0;
707 
708 out_sysfs_cleanup:
709 	v9fs_sysfs_cleanup();
710 
711 out_cache:
712 	v9fs_cache_unregister();
713 
714 	return err;
715 }
716 
717 /**
718  * exit_v9fs - shutdown module
719  *
720  */
721 
722 static void __exit exit_v9fs(void)
723 {
724 	v9fs_sysfs_cleanup();
725 	v9fs_cache_unregister();
726 	unregister_filesystem(&v9fs_fs_type);
727 }
728 
729 module_init(init_v9fs)
730 module_exit(exit_v9fs)
731 
732 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
733 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
734 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
735 MODULE_LICENSE("GPL");
736