xref: /openbmc/linux/fs/9p/v9fs.c (revision 71501859) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/fs/9p/v9fs.c
4  *
5  *  This file contains functions assisting in mapping VFS to 9P2000
6  *
7  *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
8  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
9  */
10 
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12 
13 #include <linux/module.h>
14 #include <linux/errno.h>
15 #include <linux/fs.h>
16 #include <linux/sched.h>
17 #include <linux/cred.h>
18 #include <linux/parser.h>
19 #include <linux/idr.h>
20 #include <linux/slab.h>
21 #include <linux/seq_file.h>
22 #include <net/9p/9p.h>
23 #include <net/9p/client.h>
24 #include <net/9p/transport.h>
25 #include "v9fs.h"
26 #include "v9fs_vfs.h"
27 #include "cache.h"
28 
29 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
30 static LIST_HEAD(v9fs_sessionlist);
31 struct kmem_cache *v9fs_inode_cache;
32 
33 /*
34  * Option Parsing (code inspired by NFS code)
35  *  NOTE: each transport will parse its own options
36  */
37 
38 enum {
39 	/* Options that take integer arguments */
40 	Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
41 	/* String options */
42 	Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
43 	/* Options that take no arguments */
44 	Opt_nodevmap,
45 	/* Cache options */
46 	Opt_cache_loose, Opt_fscache, Opt_mmap,
47 	/* Access options */
48 	Opt_access, Opt_posixacl,
49 	/* Lock timeout option */
50 	Opt_locktimeout,
51 	/* Error token */
52 	Opt_err
53 };
54 
55 static const match_table_t tokens = {
56 	{Opt_debug, "debug=%x"},
57 	{Opt_dfltuid, "dfltuid=%u"},
58 	{Opt_dfltgid, "dfltgid=%u"},
59 	{Opt_afid, "afid=%u"},
60 	{Opt_uname, "uname=%s"},
61 	{Opt_remotename, "aname=%s"},
62 	{Opt_nodevmap, "nodevmap"},
63 	{Opt_cache, "cache=%s"},
64 	{Opt_cache_loose, "loose"},
65 	{Opt_fscache, "fscache"},
66 	{Opt_mmap, "mmap"},
67 	{Opt_cachetag, "cachetag=%s"},
68 	{Opt_access, "access=%s"},
69 	{Opt_posixacl, "posixacl"},
70 	{Opt_locktimeout, "locktimeout=%u"},
71 	{Opt_err, NULL}
72 };
73 
74 static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
75 	[CACHE_NONE]	= "none",
76 	[CACHE_MMAP]	= "mmap",
77 	[CACHE_LOOSE]	= "loose",
78 	[CACHE_FSCACHE]	= "fscache",
79 };
80 
81 /* Interpret mount options for cache mode */
82 static int get_cache_mode(char *s)
83 {
84 	int version = -EINVAL;
85 
86 	if (!strcmp(s, "loose")) {
87 		version = CACHE_LOOSE;
88 		p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
89 	} else if (!strcmp(s, "fscache")) {
90 		version = CACHE_FSCACHE;
91 		p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
92 	} else if (!strcmp(s, "mmap")) {
93 		version = CACHE_MMAP;
94 		p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
95 	} else if (!strcmp(s, "none")) {
96 		version = CACHE_NONE;
97 		p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
98 	} else
99 		pr_info("Unknown Cache mode %s\n", s);
100 	return version;
101 }
102 
103 /*
104  * Display the mount options in /proc/mounts.
105  */
106 int v9fs_show_options(struct seq_file *m, struct dentry *root)
107 {
108 	struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
109 
110 	if (v9ses->debug)
111 		seq_printf(m, ",debug=%x", v9ses->debug);
112 	if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
113 		seq_printf(m, ",dfltuid=%u",
114 			   from_kuid_munged(&init_user_ns, v9ses->dfltuid));
115 	if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
116 		seq_printf(m, ",dfltgid=%u",
117 			   from_kgid_munged(&init_user_ns, v9ses->dfltgid));
118 	if (v9ses->afid != ~0)
119 		seq_printf(m, ",afid=%u", v9ses->afid);
120 	if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
121 		seq_printf(m, ",uname=%s", v9ses->uname);
122 	if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
123 		seq_printf(m, ",aname=%s", v9ses->aname);
124 	if (v9ses->nodev)
125 		seq_puts(m, ",nodevmap");
126 	if (v9ses->cache)
127 		seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
128 #ifdef CONFIG_9P_FSCACHE
129 	if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
130 		seq_printf(m, ",cachetag=%s", v9ses->cachetag);
131 #endif
132 
133 	switch (v9ses->flags & V9FS_ACCESS_MASK) {
134 	case V9FS_ACCESS_USER:
135 		seq_puts(m, ",access=user");
136 		break;
137 	case V9FS_ACCESS_ANY:
138 		seq_puts(m, ",access=any");
139 		break;
140 	case V9FS_ACCESS_CLIENT:
141 		seq_puts(m, ",access=client");
142 		break;
143 	case V9FS_ACCESS_SINGLE:
144 		seq_printf(m, ",access=%u",
145 			   from_kuid_munged(&init_user_ns, v9ses->uid));
146 		break;
147 	}
148 
149 	if (v9ses->flags & V9FS_POSIX_ACL)
150 		seq_puts(m, ",posixacl");
151 
152 	return p9_show_client_options(m, v9ses->clnt);
153 }
154 
155 /**
156  * v9fs_parse_options - parse mount options into session structure
157  * @v9ses: existing v9fs session information
158  *
159  * Return 0 upon success, -ERRNO upon failure.
160  */
161 
162 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
163 {
164 	char *options, *tmp_options;
165 	substring_t args[MAX_OPT_ARGS];
166 	char *p;
167 	int option = 0;
168 	char *s, *e;
169 	int ret = 0;
170 
171 	/* setup defaults */
172 	v9ses->afid = ~0;
173 	v9ses->debug = 0;
174 	v9ses->cache = CACHE_NONE;
175 #ifdef CONFIG_9P_FSCACHE
176 	v9ses->cachetag = NULL;
177 #endif
178 	v9ses->session_lock_timeout = P9_LOCK_TIMEOUT;
179 
180 	if (!opts)
181 		return 0;
182 
183 	tmp_options = kstrdup(opts, GFP_KERNEL);
184 	if (!tmp_options) {
185 		ret = -ENOMEM;
186 		goto fail_option_alloc;
187 	}
188 	options = tmp_options;
189 
190 	while ((p = strsep(&options, ",")) != NULL) {
191 		int token, r;
192 		if (!*p)
193 			continue;
194 		token = match_token(p, tokens, args);
195 		switch (token) {
196 		case Opt_debug:
197 			r = match_int(&args[0], &option);
198 			if (r < 0) {
199 				p9_debug(P9_DEBUG_ERROR,
200 					 "integer field, but no integer?\n");
201 				ret = r;
202 			} else {
203 				v9ses->debug = option;
204 #ifdef CONFIG_NET_9P_DEBUG
205 				p9_debug_level = option;
206 #endif
207 			}
208 			break;
209 
210 		case Opt_dfltuid:
211 			r = match_int(&args[0], &option);
212 			if (r < 0) {
213 				p9_debug(P9_DEBUG_ERROR,
214 					 "integer field, but no integer?\n");
215 				ret = r;
216 				continue;
217 			}
218 			v9ses->dfltuid = make_kuid(current_user_ns(), option);
219 			if (!uid_valid(v9ses->dfltuid)) {
220 				p9_debug(P9_DEBUG_ERROR,
221 					 "uid field, but not a uid?\n");
222 				ret = -EINVAL;
223 			}
224 			break;
225 		case Opt_dfltgid:
226 			r = match_int(&args[0], &option);
227 			if (r < 0) {
228 				p9_debug(P9_DEBUG_ERROR,
229 					 "integer field, but no integer?\n");
230 				ret = r;
231 				continue;
232 			}
233 			v9ses->dfltgid = make_kgid(current_user_ns(), option);
234 			if (!gid_valid(v9ses->dfltgid)) {
235 				p9_debug(P9_DEBUG_ERROR,
236 					 "gid field, but not a gid?\n");
237 				ret = -EINVAL;
238 			}
239 			break;
240 		case Opt_afid:
241 			r = match_int(&args[0], &option);
242 			if (r < 0) {
243 				p9_debug(P9_DEBUG_ERROR,
244 					 "integer field, but no integer?\n");
245 				ret = r;
246 			} else {
247 				v9ses->afid = option;
248 			}
249 			break;
250 		case Opt_uname:
251 			kfree(v9ses->uname);
252 			v9ses->uname = match_strdup(&args[0]);
253 			if (!v9ses->uname) {
254 				ret = -ENOMEM;
255 				goto free_and_return;
256 			}
257 			break;
258 		case Opt_remotename:
259 			kfree(v9ses->aname);
260 			v9ses->aname = match_strdup(&args[0]);
261 			if (!v9ses->aname) {
262 				ret = -ENOMEM;
263 				goto free_and_return;
264 			}
265 			break;
266 		case Opt_nodevmap:
267 			v9ses->nodev = 1;
268 			break;
269 		case Opt_cache_loose:
270 			v9ses->cache = CACHE_LOOSE;
271 			break;
272 		case Opt_fscache:
273 			v9ses->cache = CACHE_FSCACHE;
274 			break;
275 		case Opt_mmap:
276 			v9ses->cache = CACHE_MMAP;
277 			break;
278 		case Opt_cachetag:
279 #ifdef CONFIG_9P_FSCACHE
280 			kfree(v9ses->cachetag);
281 			v9ses->cachetag = match_strdup(&args[0]);
282 			if (!v9ses->cachetag) {
283 				ret = -ENOMEM;
284 				goto free_and_return;
285 			}
286 #endif
287 			break;
288 		case Opt_cache:
289 			s = match_strdup(&args[0]);
290 			if (!s) {
291 				ret = -ENOMEM;
292 				p9_debug(P9_DEBUG_ERROR,
293 					 "problem allocating copy of cache arg\n");
294 				goto free_and_return;
295 			}
296 			r = get_cache_mode(s);
297 			if (r < 0)
298 				ret = r;
299 			else
300 				v9ses->cache = r;
301 
302 			kfree(s);
303 			break;
304 
305 		case Opt_access:
306 			s = match_strdup(&args[0]);
307 			if (!s) {
308 				ret = -ENOMEM;
309 				p9_debug(P9_DEBUG_ERROR,
310 					 "problem allocating copy of access arg\n");
311 				goto free_and_return;
312 			}
313 
314 			v9ses->flags &= ~V9FS_ACCESS_MASK;
315 			if (strcmp(s, "user") == 0)
316 				v9ses->flags |= V9FS_ACCESS_USER;
317 			else if (strcmp(s, "any") == 0)
318 				v9ses->flags |= V9FS_ACCESS_ANY;
319 			else if (strcmp(s, "client") == 0) {
320 				v9ses->flags |= V9FS_ACCESS_CLIENT;
321 			} else {
322 				uid_t uid;
323 				v9ses->flags |= V9FS_ACCESS_SINGLE;
324 				uid = simple_strtoul(s, &e, 10);
325 				if (*e != '\0') {
326 					ret = -EINVAL;
327 					pr_info("Unknown access argument %s\n",
328 						s);
329 					kfree(s);
330 					continue;
331 				}
332 				v9ses->uid = make_kuid(current_user_ns(), uid);
333 				if (!uid_valid(v9ses->uid)) {
334 					ret = -EINVAL;
335 					pr_info("Unknown uid %s\n", s);
336 				}
337 			}
338 
339 			kfree(s);
340 			break;
341 
342 		case Opt_posixacl:
343 #ifdef CONFIG_9P_FS_POSIX_ACL
344 			v9ses->flags |= V9FS_POSIX_ACL;
345 #else
346 			p9_debug(P9_DEBUG_ERROR,
347 				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
348 #endif
349 			break;
350 
351 		case Opt_locktimeout:
352 			r = match_int(&args[0], &option);
353 			if (r < 0) {
354 				p9_debug(P9_DEBUG_ERROR,
355 					 "integer field, but no integer?\n");
356 				ret = r;
357 				continue;
358 			}
359 			if (option < 1) {
360 				p9_debug(P9_DEBUG_ERROR,
361 					 "locktimeout must be a greater than zero integer.\n");
362 				ret = -EINVAL;
363 				continue;
364 			}
365 			v9ses->session_lock_timeout = (long)option * HZ;
366 			break;
367 
368 		default:
369 			continue;
370 		}
371 	}
372 
373 free_and_return:
374 	kfree(tmp_options);
375 fail_option_alloc:
376 	return ret;
377 }
378 
379 /**
380  * v9fs_session_init - initialize session
381  * @v9ses: session information structure
382  * @dev_name: device being mounted
383  * @data: options
384  *
385  */
386 
387 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
388 		  const char *dev_name, char *data)
389 {
390 	struct p9_fid *fid;
391 	int rc = -ENOMEM;
392 
393 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
394 	if (!v9ses->uname)
395 		goto err_names;
396 
397 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
398 	if (!v9ses->aname)
399 		goto err_names;
400 	init_rwsem(&v9ses->rename_sem);
401 
402 	v9ses->uid = INVALID_UID;
403 	v9ses->dfltuid = V9FS_DEFUID;
404 	v9ses->dfltgid = V9FS_DEFGID;
405 
406 	v9ses->clnt = p9_client_create(dev_name, data);
407 	if (IS_ERR(v9ses->clnt)) {
408 		rc = PTR_ERR(v9ses->clnt);
409 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
410 		goto err_names;
411 	}
412 
413 	v9ses->flags = V9FS_ACCESS_USER;
414 
415 	if (p9_is_proto_dotl(v9ses->clnt)) {
416 		v9ses->flags = V9FS_ACCESS_CLIENT;
417 		v9ses->flags |= V9FS_PROTO_2000L;
418 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
419 		v9ses->flags |= V9FS_PROTO_2000U;
420 	}
421 
422 	rc = v9fs_parse_options(v9ses, data);
423 	if (rc < 0)
424 		goto err_clnt;
425 
426 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
427 
428 	if (!v9fs_proto_dotl(v9ses) &&
429 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
430 		/*
431 		 * We support ACCESS_CLIENT only for dotl.
432 		 * Fall back to ACCESS_USER
433 		 */
434 		v9ses->flags &= ~V9FS_ACCESS_MASK;
435 		v9ses->flags |= V9FS_ACCESS_USER;
436 	}
437 	/*FIXME !! */
438 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
439 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
440 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
441 
442 		v9ses->flags &= ~V9FS_ACCESS_MASK;
443 		v9ses->flags |= V9FS_ACCESS_ANY;
444 		v9ses->uid = INVALID_UID;
445 	}
446 	if (!v9fs_proto_dotl(v9ses) ||
447 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
448 		/*
449 		 * We support ACL checks on clinet only if the protocol is
450 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
451 		 */
452 		v9ses->flags &= ~V9FS_ACL_MASK;
453 	}
454 
455 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
456 							v9ses->aname);
457 	if (IS_ERR(fid)) {
458 		rc = PTR_ERR(fid);
459 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
460 		goto err_clnt;
461 	}
462 
463 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
464 		fid->uid = v9ses->uid;
465 	else
466 		fid->uid = INVALID_UID;
467 
468 #ifdef CONFIG_9P_FSCACHE
469 	/* register the session for caching */
470 	v9fs_cache_session_get_cookie(v9ses);
471 #endif
472 	spin_lock(&v9fs_sessionlist_lock);
473 	list_add(&v9ses->slist, &v9fs_sessionlist);
474 	spin_unlock(&v9fs_sessionlist_lock);
475 
476 	return fid;
477 
478 err_clnt:
479 #ifdef CONFIG_9P_FSCACHE
480 	kfree(v9ses->cachetag);
481 #endif
482 	p9_client_destroy(v9ses->clnt);
483 err_names:
484 	kfree(v9ses->uname);
485 	kfree(v9ses->aname);
486 	return ERR_PTR(rc);
487 }
488 
489 /**
490  * v9fs_session_close - shutdown a session
491  * @v9ses: session information structure
492  *
493  */
494 
495 void v9fs_session_close(struct v9fs_session_info *v9ses)
496 {
497 	if (v9ses->clnt) {
498 		p9_client_destroy(v9ses->clnt);
499 		v9ses->clnt = NULL;
500 	}
501 
502 #ifdef CONFIG_9P_FSCACHE
503 	if (v9ses->fscache)
504 		v9fs_cache_session_put_cookie(v9ses);
505 	kfree(v9ses->cachetag);
506 #endif
507 	kfree(v9ses->uname);
508 	kfree(v9ses->aname);
509 
510 	spin_lock(&v9fs_sessionlist_lock);
511 	list_del(&v9ses->slist);
512 	spin_unlock(&v9fs_sessionlist_lock);
513 }
514 
515 /**
516  * v9fs_session_cancel - terminate a session
517  * @v9ses: session to terminate
518  *
519  * mark transport as disconnected and cancel all pending requests.
520  */
521 
522 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
523 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
524 	p9_client_disconnect(v9ses->clnt);
525 }
526 
527 /**
528  * v9fs_session_begin_cancel - Begin terminate of a session
529  * @v9ses: session to terminate
530  *
531  * After this call we don't allow any request other than clunk.
532  */
533 
534 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
535 {
536 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
537 	p9_client_begin_disconnect(v9ses->clnt);
538 }
539 
540 extern int v9fs_error_init(void);
541 
542 static struct kobject *v9fs_kobj;
543 
544 #ifdef CONFIG_9P_FSCACHE
545 /**
546  * caches_show - list caches associated with a session
547  *
548  * Returns the size of buffer written.
549  */
550 
551 static ssize_t caches_show(struct kobject *kobj,
552 			   struct kobj_attribute *attr,
553 			   char *buf)
554 {
555 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
556 	struct v9fs_session_info *v9ses;
557 
558 	spin_lock(&v9fs_sessionlist_lock);
559 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
560 		if (v9ses->cachetag) {
561 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
562 			if (n < 0) {
563 				count = n;
564 				break;
565 			}
566 
567 			count += n;
568 			limit -= n;
569 		}
570 	}
571 
572 	spin_unlock(&v9fs_sessionlist_lock);
573 	return count;
574 }
575 
576 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
577 #endif /* CONFIG_9P_FSCACHE */
578 
579 static struct attribute *v9fs_attrs[] = {
580 #ifdef CONFIG_9P_FSCACHE
581 	&v9fs_attr_cache.attr,
582 #endif
583 	NULL,
584 };
585 
586 static const struct attribute_group v9fs_attr_group = {
587 	.attrs = v9fs_attrs,
588 };
589 
590 /**
591  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
592  *
593  */
594 
595 static int __init v9fs_sysfs_init(void)
596 {
597 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
598 	if (!v9fs_kobj)
599 		return -ENOMEM;
600 
601 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
602 		kobject_put(v9fs_kobj);
603 		return -ENOMEM;
604 	}
605 
606 	return 0;
607 }
608 
609 /**
610  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
611  *
612  */
613 
614 static void v9fs_sysfs_cleanup(void)
615 {
616 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
617 	kobject_put(v9fs_kobj);
618 }
619 
620 static void v9fs_inode_init_once(void *foo)
621 {
622 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
623 #ifdef CONFIG_9P_FSCACHE
624 	v9inode->fscache = NULL;
625 #endif
626 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
627 	inode_init_once(&v9inode->vfs_inode);
628 }
629 
630 /**
631  * v9fs_init_inode_cache - initialize a cache for 9P
632  * Returns 0 on success.
633  */
634 static int v9fs_init_inode_cache(void)
635 {
636 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
637 					  sizeof(struct v9fs_inode),
638 					  0, (SLAB_RECLAIM_ACCOUNT|
639 					      SLAB_MEM_SPREAD|SLAB_ACCOUNT),
640 					  v9fs_inode_init_once);
641 	if (!v9fs_inode_cache)
642 		return -ENOMEM;
643 
644 	return 0;
645 }
646 
647 /**
648  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
649  *
650  */
651 static void v9fs_destroy_inode_cache(void)
652 {
653 	/*
654 	 * Make sure all delayed rcu free inodes are flushed before we
655 	 * destroy cache.
656 	 */
657 	rcu_barrier();
658 	kmem_cache_destroy(v9fs_inode_cache);
659 }
660 
661 static int v9fs_cache_register(void)
662 {
663 	int ret;
664 	ret = v9fs_init_inode_cache();
665 	if (ret < 0)
666 		return ret;
667 #ifdef CONFIG_9P_FSCACHE
668 	ret = fscache_register_netfs(&v9fs_cache_netfs);
669 	if (ret < 0)
670 		v9fs_destroy_inode_cache();
671 #endif
672 	return ret;
673 }
674 
675 static void v9fs_cache_unregister(void)
676 {
677 	v9fs_destroy_inode_cache();
678 #ifdef CONFIG_9P_FSCACHE
679 	fscache_unregister_netfs(&v9fs_cache_netfs);
680 #endif
681 }
682 
683 /**
684  * init_v9fs - Initialize module
685  *
686  */
687 
688 static int __init init_v9fs(void)
689 {
690 	int err;
691 	pr_info("Installing v9fs 9p2000 file system support\n");
692 	/* TODO: Setup list of registered trasnport modules */
693 
694 	err = v9fs_cache_register();
695 	if (err < 0) {
696 		pr_err("Failed to register v9fs for caching\n");
697 		return err;
698 	}
699 
700 	err = v9fs_sysfs_init();
701 	if (err < 0) {
702 		pr_err("Failed to register with sysfs\n");
703 		goto out_cache;
704 	}
705 	err = register_filesystem(&v9fs_fs_type);
706 	if (err < 0) {
707 		pr_err("Failed to register filesystem\n");
708 		goto out_sysfs_cleanup;
709 	}
710 
711 	return 0;
712 
713 out_sysfs_cleanup:
714 	v9fs_sysfs_cleanup();
715 
716 out_cache:
717 	v9fs_cache_unregister();
718 
719 	return err;
720 }
721 
722 /**
723  * exit_v9fs - shutdown module
724  *
725  */
726 
727 static void __exit exit_v9fs(void)
728 {
729 	v9fs_sysfs_cleanup();
730 	v9fs_cache_unregister();
731 	unregister_filesystem(&v9fs_fs_type);
732 }
733 
734 module_init(init_v9fs)
735 module_exit(exit_v9fs)
736 
737 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
738 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
739 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
740 MODULE_LICENSE("GPL");
741