xref: /linux/fs/9p/v9fs.c (revision aec499c75cf8e0b599be4d559e6922b613085f8f) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  This file contains functions assisting in mapping VFS to 9P2000
4  *
5  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
6  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
7  */
8 
9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 
11 #include <linux/module.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/sched.h>
15 #include <linux/cred.h>
16 #include <linux/parser.h>
17 #include <linux/idr.h>
18 #include <linux/slab.h>
19 #include <linux/seq_file.h>
20 #include <net/9p/9p.h>
21 #include <net/9p/client.h>
22 #include <net/9p/transport.h>
23 #include "v9fs.h"
24 #include "v9fs_vfs.h"
25 #include "cache.h"
26 
27 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
28 static LIST_HEAD(v9fs_sessionlist);
29 struct kmem_cache *v9fs_inode_cache;
30 
31 /*
32  * Option Parsing (code inspired by NFS code)
33  *  NOTE: each transport will parse its own options
34  */
35 
36 enum {
37 	/* Options that take integer arguments */
38 	Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
39 	/* String options */
40 	Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
41 	/* Options that take no arguments */
42 	Opt_nodevmap,
43 	/* Cache options */
44 	Opt_cache_loose, Opt_fscache, Opt_mmap,
45 	/* Access options */
46 	Opt_access, Opt_posixacl,
47 	/* Lock timeout option */
48 	Opt_locktimeout,
49 	/* Error token */
50 	Opt_err
51 };
52 
53 static const match_table_t tokens = {
54 	{Opt_debug, "debug=%x"},
55 	{Opt_dfltuid, "dfltuid=%u"},
56 	{Opt_dfltgid, "dfltgid=%u"},
57 	{Opt_afid, "afid=%u"},
58 	{Opt_uname, "uname=%s"},
59 	{Opt_remotename, "aname=%s"},
60 	{Opt_nodevmap, "nodevmap"},
61 	{Opt_cache, "cache=%s"},
62 	{Opt_cache_loose, "loose"},
63 	{Opt_fscache, "fscache"},
64 	{Opt_mmap, "mmap"},
65 	{Opt_cachetag, "cachetag=%s"},
66 	{Opt_access, "access=%s"},
67 	{Opt_posixacl, "posixacl"},
68 	{Opt_locktimeout, "locktimeout=%u"},
69 	{Opt_err, NULL}
70 };
71 
72 static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
73 	[CACHE_NONE]	= "none",
74 	[CACHE_MMAP]	= "mmap",
75 	[CACHE_LOOSE]	= "loose",
76 	[CACHE_FSCACHE]	= "fscache",
77 };
78 
79 /* Interpret mount options for cache mode */
80 static int get_cache_mode(char *s)
81 {
82 	int version = -EINVAL;
83 
84 	if (!strcmp(s, "loose")) {
85 		version = CACHE_LOOSE;
86 		p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
87 	} else if (!strcmp(s, "fscache")) {
88 		version = CACHE_FSCACHE;
89 		p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
90 	} else if (!strcmp(s, "mmap")) {
91 		version = CACHE_MMAP;
92 		p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
93 	} else if (!strcmp(s, "none")) {
94 		version = CACHE_NONE;
95 		p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
96 	} else
97 		pr_info("Unknown Cache mode %s\n", s);
98 	return version;
99 }
100 
101 /*
102  * Display the mount options in /proc/mounts.
103  */
104 int v9fs_show_options(struct seq_file *m, struct dentry *root)
105 {
106 	struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
107 
108 	if (v9ses->debug)
109 		seq_printf(m, ",debug=%x", v9ses->debug);
110 	if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
111 		seq_printf(m, ",dfltuid=%u",
112 			   from_kuid_munged(&init_user_ns, v9ses->dfltuid));
113 	if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
114 		seq_printf(m, ",dfltgid=%u",
115 			   from_kgid_munged(&init_user_ns, v9ses->dfltgid));
116 	if (v9ses->afid != ~0)
117 		seq_printf(m, ",afid=%u", v9ses->afid);
118 	if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
119 		seq_printf(m, ",uname=%s", v9ses->uname);
120 	if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
121 		seq_printf(m, ",aname=%s", v9ses->aname);
122 	if (v9ses->nodev)
123 		seq_puts(m, ",nodevmap");
124 	if (v9ses->cache)
125 		seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
126 #ifdef CONFIG_9P_FSCACHE
127 	if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
128 		seq_printf(m, ",cachetag=%s", v9ses->cachetag);
129 #endif
130 
131 	switch (v9ses->flags & V9FS_ACCESS_MASK) {
132 	case V9FS_ACCESS_USER:
133 		seq_puts(m, ",access=user");
134 		break;
135 	case V9FS_ACCESS_ANY:
136 		seq_puts(m, ",access=any");
137 		break;
138 	case V9FS_ACCESS_CLIENT:
139 		seq_puts(m, ",access=client");
140 		break;
141 	case V9FS_ACCESS_SINGLE:
142 		seq_printf(m, ",access=%u",
143 			   from_kuid_munged(&init_user_ns, v9ses->uid));
144 		break;
145 	}
146 
147 	if (v9ses->flags & V9FS_POSIX_ACL)
148 		seq_puts(m, ",posixacl");
149 
150 	return p9_show_client_options(m, v9ses->clnt);
151 }
152 
153 /**
154  * v9fs_parse_options - parse mount options into session structure
155  * @v9ses: existing v9fs session information
156  * @opts: The mount option string
157  *
158  * Return 0 upon success, -ERRNO upon failure.
159  */
160 
161 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
162 {
163 	char *options, *tmp_options;
164 	substring_t args[MAX_OPT_ARGS];
165 	char *p;
166 	int option = 0;
167 	char *s;
168 	int ret = 0;
169 
170 	/* setup defaults */
171 	v9ses->afid = ~0;
172 	v9ses->debug = 0;
173 	v9ses->cache = CACHE_NONE;
174 #ifdef CONFIG_9P_FSCACHE
175 	v9ses->cachetag = NULL;
176 #endif
177 	v9ses->session_lock_timeout = P9_LOCK_TIMEOUT;
178 
179 	if (!opts)
180 		return 0;
181 
182 	tmp_options = kstrdup(opts, GFP_KERNEL);
183 	if (!tmp_options) {
184 		ret = -ENOMEM;
185 		goto fail_option_alloc;
186 	}
187 	options = tmp_options;
188 
189 	while ((p = strsep(&options, ",")) != NULL) {
190 		int token, r;
191 
192 		if (!*p)
193 			continue;
194 
195 		token = match_token(p, tokens, args);
196 		switch (token) {
197 		case Opt_debug:
198 			r = match_int(&args[0], &option);
199 			if (r < 0) {
200 				p9_debug(P9_DEBUG_ERROR,
201 					 "integer field, but no integer?\n");
202 				ret = r;
203 			} else {
204 				v9ses->debug = option;
205 #ifdef CONFIG_NET_9P_DEBUG
206 				p9_debug_level = option;
207 #endif
208 			}
209 			break;
210 
211 		case Opt_dfltuid:
212 			r = match_int(&args[0], &option);
213 			if (r < 0) {
214 				p9_debug(P9_DEBUG_ERROR,
215 					 "integer field, but no integer?\n");
216 				ret = r;
217 				continue;
218 			}
219 			v9ses->dfltuid = make_kuid(current_user_ns(), option);
220 			if (!uid_valid(v9ses->dfltuid)) {
221 				p9_debug(P9_DEBUG_ERROR,
222 					 "uid field, but not a uid?\n");
223 				ret = -EINVAL;
224 			}
225 			break;
226 		case Opt_dfltgid:
227 			r = match_int(&args[0], &option);
228 			if (r < 0) {
229 				p9_debug(P9_DEBUG_ERROR,
230 					 "integer field, but no integer?\n");
231 				ret = r;
232 				continue;
233 			}
234 			v9ses->dfltgid = make_kgid(current_user_ns(), option);
235 			if (!gid_valid(v9ses->dfltgid)) {
236 				p9_debug(P9_DEBUG_ERROR,
237 					 "gid field, but not a gid?\n");
238 				ret = -EINVAL;
239 			}
240 			break;
241 		case Opt_afid:
242 			r = match_int(&args[0], &option);
243 			if (r < 0) {
244 				p9_debug(P9_DEBUG_ERROR,
245 					 "integer field, but no integer?\n");
246 				ret = r;
247 			} else {
248 				v9ses->afid = option;
249 			}
250 			break;
251 		case Opt_uname:
252 			kfree(v9ses->uname);
253 			v9ses->uname = match_strdup(&args[0]);
254 			if (!v9ses->uname) {
255 				ret = -ENOMEM;
256 				goto free_and_return;
257 			}
258 			break;
259 		case Opt_remotename:
260 			kfree(v9ses->aname);
261 			v9ses->aname = match_strdup(&args[0]);
262 			if (!v9ses->aname) {
263 				ret = -ENOMEM;
264 				goto free_and_return;
265 			}
266 			break;
267 		case Opt_nodevmap:
268 			v9ses->nodev = 1;
269 			break;
270 		case Opt_cache_loose:
271 			v9ses->cache = CACHE_LOOSE;
272 			break;
273 		case Opt_fscache:
274 			v9ses->cache = CACHE_FSCACHE;
275 			break;
276 		case Opt_mmap:
277 			v9ses->cache = CACHE_MMAP;
278 			break;
279 		case Opt_cachetag:
280 #ifdef CONFIG_9P_FSCACHE
281 			kfree(v9ses->cachetag);
282 			v9ses->cachetag = match_strdup(&args[0]);
283 			if (!v9ses->cachetag) {
284 				ret = -ENOMEM;
285 				goto free_and_return;
286 			}
287 #endif
288 			break;
289 		case Opt_cache:
290 			s = match_strdup(&args[0]);
291 			if (!s) {
292 				ret = -ENOMEM;
293 				p9_debug(P9_DEBUG_ERROR,
294 					 "problem allocating copy of cache arg\n");
295 				goto free_and_return;
296 			}
297 			r = get_cache_mode(s);
298 			if (r < 0)
299 				ret = r;
300 			else
301 				v9ses->cache = r;
302 
303 			kfree(s);
304 			break;
305 
306 		case Opt_access:
307 			s = match_strdup(&args[0]);
308 			if (!s) {
309 				ret = -ENOMEM;
310 				p9_debug(P9_DEBUG_ERROR,
311 					 "problem allocating copy of access arg\n");
312 				goto free_and_return;
313 			}
314 
315 			v9ses->flags &= ~V9FS_ACCESS_MASK;
316 			if (strcmp(s, "user") == 0)
317 				v9ses->flags |= V9FS_ACCESS_USER;
318 			else if (strcmp(s, "any") == 0)
319 				v9ses->flags |= V9FS_ACCESS_ANY;
320 			else if (strcmp(s, "client") == 0) {
321 				v9ses->flags |= V9FS_ACCESS_CLIENT;
322 			} else {
323 				uid_t uid;
324 
325 				v9ses->flags |= V9FS_ACCESS_SINGLE;
326 				r = kstrtouint(s, 10, &uid);
327 				if (r) {
328 					ret = r;
329 					pr_info("Unknown access argument %s: %d\n",
330 						s, r);
331 					kfree(s);
332 					continue;
333 				}
334 				v9ses->uid = make_kuid(current_user_ns(), uid);
335 				if (!uid_valid(v9ses->uid)) {
336 					ret = -EINVAL;
337 					pr_info("Unknown uid %s\n", s);
338 				}
339 			}
340 
341 			kfree(s);
342 			break;
343 
344 		case Opt_posixacl:
345 #ifdef CONFIG_9P_FS_POSIX_ACL
346 			v9ses->flags |= V9FS_POSIX_ACL;
347 #else
348 			p9_debug(P9_DEBUG_ERROR,
349 				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
350 #endif
351 			break;
352 
353 		case Opt_locktimeout:
354 			r = match_int(&args[0], &option);
355 			if (r < 0) {
356 				p9_debug(P9_DEBUG_ERROR,
357 					 "integer field, but no integer?\n");
358 				ret = r;
359 				continue;
360 			}
361 			if (option < 1) {
362 				p9_debug(P9_DEBUG_ERROR,
363 					 "locktimeout must be a greater than zero integer.\n");
364 				ret = -EINVAL;
365 				continue;
366 			}
367 			v9ses->session_lock_timeout = (long)option * HZ;
368 			break;
369 
370 		default:
371 			continue;
372 		}
373 	}
374 
375 free_and_return:
376 	kfree(tmp_options);
377 fail_option_alloc:
378 	return ret;
379 }
380 
381 /**
382  * v9fs_session_init - initialize session
383  * @v9ses: session information structure
384  * @dev_name: device being mounted
385  * @data: options
386  *
387  */
388 
389 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
390 		  const char *dev_name, char *data)
391 {
392 	struct p9_fid *fid;
393 	int rc = -ENOMEM;
394 
395 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
396 	if (!v9ses->uname)
397 		goto err_names;
398 
399 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
400 	if (!v9ses->aname)
401 		goto err_names;
402 	init_rwsem(&v9ses->rename_sem);
403 
404 	v9ses->uid = INVALID_UID;
405 	v9ses->dfltuid = V9FS_DEFUID;
406 	v9ses->dfltgid = V9FS_DEFGID;
407 
408 	v9ses->clnt = p9_client_create(dev_name, data);
409 	if (IS_ERR(v9ses->clnt)) {
410 		rc = PTR_ERR(v9ses->clnt);
411 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
412 		goto err_names;
413 	}
414 
415 	v9ses->flags = V9FS_ACCESS_USER;
416 
417 	if (p9_is_proto_dotl(v9ses->clnt)) {
418 		v9ses->flags = V9FS_ACCESS_CLIENT;
419 		v9ses->flags |= V9FS_PROTO_2000L;
420 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
421 		v9ses->flags |= V9FS_PROTO_2000U;
422 	}
423 
424 	rc = v9fs_parse_options(v9ses, data);
425 	if (rc < 0)
426 		goto err_clnt;
427 
428 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
429 
430 	if (!v9fs_proto_dotl(v9ses) &&
431 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
432 		/*
433 		 * We support ACCESS_CLIENT only for dotl.
434 		 * Fall back to ACCESS_USER
435 		 */
436 		v9ses->flags &= ~V9FS_ACCESS_MASK;
437 		v9ses->flags |= V9FS_ACCESS_USER;
438 	}
439 	/*FIXME !! */
440 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
441 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
442 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
443 
444 		v9ses->flags &= ~V9FS_ACCESS_MASK;
445 		v9ses->flags |= V9FS_ACCESS_ANY;
446 		v9ses->uid = INVALID_UID;
447 	}
448 	if (!v9fs_proto_dotl(v9ses) ||
449 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
450 		/*
451 		 * We support ACL checks on clinet only if the protocol is
452 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
453 		 */
454 		v9ses->flags &= ~V9FS_ACL_MASK;
455 	}
456 
457 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
458 							v9ses->aname);
459 	if (IS_ERR(fid)) {
460 		rc = PTR_ERR(fid);
461 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
462 		goto err_clnt;
463 	}
464 
465 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
466 		fid->uid = v9ses->uid;
467 	else
468 		fid->uid = INVALID_UID;
469 
470 #ifdef CONFIG_9P_FSCACHE
471 	/* register the session for caching */
472 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
473 		rc = v9fs_cache_session_get_cookie(v9ses, dev_name);
474 		if (rc < 0)
475 			goto err_clnt;
476 	}
477 #endif
478 	spin_lock(&v9fs_sessionlist_lock);
479 	list_add(&v9ses->slist, &v9fs_sessionlist);
480 	spin_unlock(&v9fs_sessionlist_lock);
481 
482 	return fid;
483 
484 err_clnt:
485 #ifdef CONFIG_9P_FSCACHE
486 	kfree(v9ses->cachetag);
487 #endif
488 	p9_client_destroy(v9ses->clnt);
489 err_names:
490 	kfree(v9ses->uname);
491 	kfree(v9ses->aname);
492 	return ERR_PTR(rc);
493 }
494 
495 /**
496  * v9fs_session_close - shutdown a session
497  * @v9ses: session information structure
498  *
499  */
500 
501 void v9fs_session_close(struct v9fs_session_info *v9ses)
502 {
503 	if (v9ses->clnt) {
504 		p9_client_destroy(v9ses->clnt);
505 		v9ses->clnt = NULL;
506 	}
507 
508 #ifdef CONFIG_9P_FSCACHE
509 	fscache_relinquish_volume(v9fs_session_cache(v9ses), NULL, false);
510 	kfree(v9ses->cachetag);
511 #endif
512 	kfree(v9ses->uname);
513 	kfree(v9ses->aname);
514 
515 	spin_lock(&v9fs_sessionlist_lock);
516 	list_del(&v9ses->slist);
517 	spin_unlock(&v9fs_sessionlist_lock);
518 }
519 
520 /**
521  * v9fs_session_cancel - terminate a session
522  * @v9ses: session to terminate
523  *
524  * mark transport as disconnected and cancel all pending requests.
525  */
526 
527 void v9fs_session_cancel(struct v9fs_session_info *v9ses)
528 {
529 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
530 	p9_client_disconnect(v9ses->clnt);
531 }
532 
533 /**
534  * v9fs_session_begin_cancel - Begin terminate of a session
535  * @v9ses: session to terminate
536  *
537  * After this call we don't allow any request other than clunk.
538  */
539 
540 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
541 {
542 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
543 	p9_client_begin_disconnect(v9ses->clnt);
544 }
545 
546 extern int v9fs_error_init(void);
547 
548 static struct kobject *v9fs_kobj;
549 
550 #ifdef CONFIG_9P_FSCACHE
551 /*
552  * List caches associated with a session
553  */
554 static ssize_t caches_show(struct kobject *kobj,
555 			   struct kobj_attribute *attr,
556 			   char *buf)
557 {
558 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
559 	struct v9fs_session_info *v9ses;
560 
561 	spin_lock(&v9fs_sessionlist_lock);
562 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
563 		if (v9ses->cachetag) {
564 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
565 			if (n < 0) {
566 				count = n;
567 				break;
568 			}
569 
570 			count += n;
571 			limit -= n;
572 		}
573 	}
574 
575 	spin_unlock(&v9fs_sessionlist_lock);
576 	return count;
577 }
578 
579 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
580 #endif /* CONFIG_9P_FSCACHE */
581 
582 static struct attribute *v9fs_attrs[] = {
583 #ifdef CONFIG_9P_FSCACHE
584 	&v9fs_attr_cache.attr,
585 #endif
586 	NULL,
587 };
588 
589 static const struct attribute_group v9fs_attr_group = {
590 	.attrs = v9fs_attrs,
591 };
592 
593 /**
594  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
595  *
596  */
597 
598 static int __init v9fs_sysfs_init(void)
599 {
600 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
601 	if (!v9fs_kobj)
602 		return -ENOMEM;
603 
604 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
605 		kobject_put(v9fs_kobj);
606 		return -ENOMEM;
607 	}
608 
609 	return 0;
610 }
611 
612 /**
613  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
614  *
615  */
616 
617 static void v9fs_sysfs_cleanup(void)
618 {
619 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
620 	kobject_put(v9fs_kobj);
621 }
622 
623 static void v9fs_inode_init_once(void *foo)
624 {
625 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
626 #ifdef CONFIG_9P_FSCACHE
627 	v9inode->fscache = NULL;
628 #endif
629 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
630 	inode_init_once(&v9inode->vfs_inode);
631 }
632 
633 /**
634  * v9fs_init_inode_cache - initialize a cache for 9P
635  * Returns 0 on success.
636  */
637 static int v9fs_init_inode_cache(void)
638 {
639 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
640 					  sizeof(struct v9fs_inode),
641 					  0, (SLAB_RECLAIM_ACCOUNT|
642 					      SLAB_MEM_SPREAD|SLAB_ACCOUNT),
643 					  v9fs_inode_init_once);
644 	if (!v9fs_inode_cache)
645 		return -ENOMEM;
646 
647 	return 0;
648 }
649 
650 /**
651  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
652  *
653  */
654 static void v9fs_destroy_inode_cache(void)
655 {
656 	/*
657 	 * Make sure all delayed rcu free inodes are flushed before we
658 	 * destroy cache.
659 	 */
660 	rcu_barrier();
661 	kmem_cache_destroy(v9fs_inode_cache);
662 }
663 
664 static int v9fs_cache_register(void)
665 {
666 	int ret;
667 
668 	ret = v9fs_init_inode_cache();
669 	if (ret < 0)
670 		return ret;
671 	return ret;
672 }
673 
674 static void v9fs_cache_unregister(void)
675 {
676 	v9fs_destroy_inode_cache();
677 }
678 
679 /**
680  * init_v9fs - Initialize module
681  *
682  */
683 
684 static int __init init_v9fs(void)
685 {
686 	int err;
687 
688 	pr_info("Installing v9fs 9p2000 file system support\n");
689 	/* TODO: Setup list of registered trasnport modules */
690 
691 	err = v9fs_cache_register();
692 	if (err < 0) {
693 		pr_err("Failed to register v9fs for caching\n");
694 		return err;
695 	}
696 
697 	err = v9fs_sysfs_init();
698 	if (err < 0) {
699 		pr_err("Failed to register with sysfs\n");
700 		goto out_cache;
701 	}
702 	err = register_filesystem(&v9fs_fs_type);
703 	if (err < 0) {
704 		pr_err("Failed to register filesystem\n");
705 		goto out_sysfs_cleanup;
706 	}
707 
708 	return 0;
709 
710 out_sysfs_cleanup:
711 	v9fs_sysfs_cleanup();
712 
713 out_cache:
714 	v9fs_cache_unregister();
715 
716 	return err;
717 }
718 
719 /**
720  * exit_v9fs - shutdown module
721  *
722  */
723 
724 static void __exit exit_v9fs(void)
725 {
726 	v9fs_sysfs_cleanup();
727 	v9fs_cache_unregister();
728 	unregister_filesystem(&v9fs_fs_type);
729 }
730 
731 module_init(init_v9fs)
732 module_exit(exit_v9fs)
733 
734 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
735 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
736 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
737 MODULE_LICENSE("GPL");
738