xref: /openbmc/linux/fs/9p/v9fs.c (revision f9a82c48) 
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 	/* Lock timeout option */
65 	Opt_locktimeout,
66 	/* Error token */
67 	Opt_err
68 };
69 
70 static const match_table_t tokens = {
71 	{Opt_debug, "debug=%x"},
72 	{Opt_dfltuid, "dfltuid=%u"},
73 	{Opt_dfltgid, "dfltgid=%u"},
74 	{Opt_afid, "afid=%u"},
75 	{Opt_uname, "uname=%s"},
76 	{Opt_remotename, "aname=%s"},
77 	{Opt_nodevmap, "nodevmap"},
78 	{Opt_cache, "cache=%s"},
79 	{Opt_cache_loose, "loose"},
80 	{Opt_fscache, "fscache"},
81 	{Opt_mmap, "mmap"},
82 	{Opt_cachetag, "cachetag=%s"},
83 	{Opt_access, "access=%s"},
84 	{Opt_posixacl, "posixacl"},
85 	{Opt_locktimeout, "locktimeout=%u"},
86 	{Opt_err, NULL}
87 };
88 
89 static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
90 	[CACHE_NONE]	= "none",
91 	[CACHE_MMAP]	= "mmap",
92 	[CACHE_LOOSE]	= "loose",
93 	[CACHE_FSCACHE]	= "fscache",
94 };
95 
96 /* Interpret mount options for cache mode */
97 static int get_cache_mode(char *s)
98 {
99 	int version = -EINVAL;
100 
101 	if (!strcmp(s, "loose")) {
102 		version = CACHE_LOOSE;
103 		p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
104 	} else if (!strcmp(s, "fscache")) {
105 		version = CACHE_FSCACHE;
106 		p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
107 	} else if (!strcmp(s, "mmap")) {
108 		version = CACHE_MMAP;
109 		p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
110 	} else if (!strcmp(s, "none")) {
111 		version = CACHE_NONE;
112 		p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
113 	} else
114 		pr_info("Unknown Cache mode %s\n", s);
115 	return version;
116 }
117 
118 /*
119  * Display the mount options in /proc/mounts.
120  */
121 int v9fs_show_options(struct seq_file *m, struct dentry *root)
122 {
123 	struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
124 
125 	if (v9ses->debug)
126 		seq_printf(m, ",debug=%x", v9ses->debug);
127 	if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
128 		seq_printf(m, ",dfltuid=%u",
129 			   from_kuid_munged(&init_user_ns, v9ses->dfltuid));
130 	if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
131 		seq_printf(m, ",dfltgid=%u",
132 			   from_kgid_munged(&init_user_ns, v9ses->dfltgid));
133 	if (v9ses->afid != ~0)
134 		seq_printf(m, ",afid=%u", v9ses->afid);
135 	if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
136 		seq_printf(m, ",uname=%s", v9ses->uname);
137 	if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
138 		seq_printf(m, ",aname=%s", v9ses->aname);
139 	if (v9ses->nodev)
140 		seq_puts(m, ",nodevmap");
141 	if (v9ses->cache)
142 		seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
143 #ifdef CONFIG_9P_FSCACHE
144 	if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
145 		seq_printf(m, ",cachetag=%s", v9ses->cachetag);
146 #endif
147 
148 	switch (v9ses->flags & V9FS_ACCESS_MASK) {
149 	case V9FS_ACCESS_USER:
150 		seq_puts(m, ",access=user");
151 		break;
152 	case V9FS_ACCESS_ANY:
153 		seq_puts(m, ",access=any");
154 		break;
155 	case V9FS_ACCESS_CLIENT:
156 		seq_puts(m, ",access=client");
157 		break;
158 	case V9FS_ACCESS_SINGLE:
159 		seq_printf(m, ",access=%u",
160 			   from_kuid_munged(&init_user_ns, v9ses->uid));
161 		break;
162 	}
163 
164 	if (v9ses->flags & V9FS_POSIX_ACL)
165 		seq_puts(m, ",posixacl");
166 
167 	return p9_show_client_options(m, v9ses->clnt);
168 }
169 
170 /**
171  * v9fs_parse_options - parse mount options into session structure
172  * @v9ses: existing v9fs session information
173  *
174  * Return 0 upon success, -ERRNO upon failure.
175  */
176 
177 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
178 {
179 	char *options, *tmp_options;
180 	substring_t args[MAX_OPT_ARGS];
181 	char *p;
182 	int option = 0;
183 	char *s, *e;
184 	int ret = 0;
185 
186 	/* setup defaults */
187 	v9ses->afid = ~0;
188 	v9ses->debug = 0;
189 	v9ses->cache = CACHE_NONE;
190 #ifdef CONFIG_9P_FSCACHE
191 	v9ses->cachetag = NULL;
192 #endif
193 	v9ses->session_lock_timeout = P9_LOCK_TIMEOUT;
194 
195 	if (!opts)
196 		return 0;
197 
198 	tmp_options = kstrdup(opts, GFP_KERNEL);
199 	if (!tmp_options) {
200 		ret = -ENOMEM;
201 		goto fail_option_alloc;
202 	}
203 	options = tmp_options;
204 
205 	while ((p = strsep(&options, ",")) != NULL) {
206 		int token, r;
207 		if (!*p)
208 			continue;
209 		token = match_token(p, tokens, args);
210 		switch (token) {
211 		case Opt_debug:
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 			} else {
218 				v9ses->debug = option;
219 #ifdef CONFIG_NET_9P_DEBUG
220 				p9_debug_level = option;
221 #endif
222 			}
223 			break;
224 
225 		case Opt_dfltuid:
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->dfltuid = make_kuid(current_user_ns(), option);
234 			if (!uid_valid(v9ses->dfltuid)) {
235 				p9_debug(P9_DEBUG_ERROR,
236 					 "uid field, but not a uid?\n");
237 				ret = -EINVAL;
238 			}
239 			break;
240 		case Opt_dfltgid:
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 				continue;
247 			}
248 			v9ses->dfltgid = make_kgid(current_user_ns(), option);
249 			if (!gid_valid(v9ses->dfltgid)) {
250 				p9_debug(P9_DEBUG_ERROR,
251 					 "gid field, but not a gid?\n");
252 				ret = -EINVAL;
253 			}
254 			break;
255 		case Opt_afid:
256 			r = match_int(&args[0], &option);
257 			if (r < 0) {
258 				p9_debug(P9_DEBUG_ERROR,
259 					 "integer field, but no integer?\n");
260 				ret = r;
261 			} else {
262 				v9ses->afid = option;
263 			}
264 			break;
265 		case Opt_uname:
266 			kfree(v9ses->uname);
267 			v9ses->uname = match_strdup(&args[0]);
268 			if (!v9ses->uname) {
269 				ret = -ENOMEM;
270 				goto free_and_return;
271 			}
272 			break;
273 		case Opt_remotename:
274 			kfree(v9ses->aname);
275 			v9ses->aname = match_strdup(&args[0]);
276 			if (!v9ses->aname) {
277 				ret = -ENOMEM;
278 				goto free_and_return;
279 			}
280 			break;
281 		case Opt_nodevmap:
282 			v9ses->nodev = 1;
283 			break;
284 		case Opt_cache_loose:
285 			v9ses->cache = CACHE_LOOSE;
286 			break;
287 		case Opt_fscache:
288 			v9ses->cache = CACHE_FSCACHE;
289 			break;
290 		case Opt_mmap:
291 			v9ses->cache = CACHE_MMAP;
292 			break;
293 		case Opt_cachetag:
294 #ifdef CONFIG_9P_FSCACHE
295 			kfree(v9ses->cachetag);
296 			v9ses->cachetag = match_strdup(&args[0]);
297 			if (!v9ses->cachetag) {
298 				ret = -ENOMEM;
299 				goto free_and_return;
300 			}
301 #endif
302 			break;
303 		case Opt_cache:
304 			s = match_strdup(&args[0]);
305 			if (!s) {
306 				ret = -ENOMEM;
307 				p9_debug(P9_DEBUG_ERROR,
308 					 "problem allocating copy of cache arg\n");
309 				goto free_and_return;
310 			}
311 			r = get_cache_mode(s);
312 			if (r < 0)
313 				ret = r;
314 			else
315 				v9ses->cache = r;
316 
317 			kfree(s);
318 			break;
319 
320 		case Opt_access:
321 			s = match_strdup(&args[0]);
322 			if (!s) {
323 				ret = -ENOMEM;
324 				p9_debug(P9_DEBUG_ERROR,
325 					 "problem allocating copy of access arg\n");
326 				goto free_and_return;
327 			}
328 
329 			v9ses->flags &= ~V9FS_ACCESS_MASK;
330 			if (strcmp(s, "user") == 0)
331 				v9ses->flags |= V9FS_ACCESS_USER;
332 			else if (strcmp(s, "any") == 0)
333 				v9ses->flags |= V9FS_ACCESS_ANY;
334 			else if (strcmp(s, "client") == 0) {
335 				v9ses->flags |= V9FS_ACCESS_CLIENT;
336 			} else {
337 				uid_t uid;
338 				v9ses->flags |= V9FS_ACCESS_SINGLE;
339 				uid = simple_strtoul(s, &e, 10);
340 				if (*e != '\0') {
341 					ret = -EINVAL;
342 					pr_info("Unknown access argument %s\n",
343 						s);
344 					kfree(s);
345 					continue;
346 				}
347 				v9ses->uid = make_kuid(current_user_ns(), uid);
348 				if (!uid_valid(v9ses->uid)) {
349 					ret = -EINVAL;
350 					pr_info("Unknown uid %s\n", s);
351 				}
352 			}
353 
354 			kfree(s);
355 			break;
356 
357 		case Opt_posixacl:
358 #ifdef CONFIG_9P_FS_POSIX_ACL
359 			v9ses->flags |= V9FS_POSIX_ACL;
360 #else
361 			p9_debug(P9_DEBUG_ERROR,
362 				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
363 #endif
364 			break;
365 
366 		case Opt_locktimeout:
367 			r = match_int(&args[0], &option);
368 			if (r < 0) {
369 				p9_debug(P9_DEBUG_ERROR,
370 					 "integer field, but no integer?\n");
371 				ret = r;
372 				continue;
373 			}
374 			if (option < 1) {
375 				p9_debug(P9_DEBUG_ERROR,
376 					 "locktimeout must be a greater than zero integer.\n");
377 				ret = -EINVAL;
378 				continue;
379 			}
380 			v9ses->session_lock_timeout = (long)option * HZ;
381 			break;
382 
383 		default:
384 			continue;
385 		}
386 	}
387 
388 free_and_return:
389 	kfree(tmp_options);
390 fail_option_alloc:
391 	return ret;
392 }
393 
394 /**
395  * v9fs_session_init - initialize session
396  * @v9ses: session information structure
397  * @dev_name: device being mounted
398  * @data: options
399  *
400  */
401 
402 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
403 		  const char *dev_name, char *data)
404 {
405 	struct p9_fid *fid;
406 	int rc = -ENOMEM;
407 
408 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
409 	if (!v9ses->uname)
410 		goto err_names;
411 
412 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
413 	if (!v9ses->aname)
414 		goto err_names;
415 	init_rwsem(&v9ses->rename_sem);
416 
417 	v9ses->uid = INVALID_UID;
418 	v9ses->dfltuid = V9FS_DEFUID;
419 	v9ses->dfltgid = V9FS_DEFGID;
420 
421 	v9ses->clnt = p9_client_create(dev_name, data);
422 	if (IS_ERR(v9ses->clnt)) {
423 		rc = PTR_ERR(v9ses->clnt);
424 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
425 		goto err_names;
426 	}
427 
428 	v9ses->flags = V9FS_ACCESS_USER;
429 
430 	if (p9_is_proto_dotl(v9ses->clnt)) {
431 		v9ses->flags = V9FS_ACCESS_CLIENT;
432 		v9ses->flags |= V9FS_PROTO_2000L;
433 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
434 		v9ses->flags |= V9FS_PROTO_2000U;
435 	}
436 
437 	rc = v9fs_parse_options(v9ses, data);
438 	if (rc < 0)
439 		goto err_clnt;
440 
441 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
442 
443 	if (!v9fs_proto_dotl(v9ses) &&
444 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
445 		/*
446 		 * We support ACCESS_CLIENT only for dotl.
447 		 * Fall back to ACCESS_USER
448 		 */
449 		v9ses->flags &= ~V9FS_ACCESS_MASK;
450 		v9ses->flags |= V9FS_ACCESS_USER;
451 	}
452 	/*FIXME !! */
453 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
454 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
455 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
456 
457 		v9ses->flags &= ~V9FS_ACCESS_MASK;
458 		v9ses->flags |= V9FS_ACCESS_ANY;
459 		v9ses->uid = INVALID_UID;
460 	}
461 	if (!v9fs_proto_dotl(v9ses) ||
462 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
463 		/*
464 		 * We support ACL checks on clinet only if the protocol is
465 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
466 		 */
467 		v9ses->flags &= ~V9FS_ACL_MASK;
468 	}
469 
470 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
471 							v9ses->aname);
472 	if (IS_ERR(fid)) {
473 		rc = PTR_ERR(fid);
474 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
475 		goto err_clnt;
476 	}
477 
478 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
479 		fid->uid = v9ses->uid;
480 	else
481 		fid->uid = INVALID_UID;
482 
483 #ifdef CONFIG_9P_FSCACHE
484 	/* register the session for caching */
485 	v9fs_cache_session_get_cookie(v9ses);
486 #endif
487 	spin_lock(&v9fs_sessionlist_lock);
488 	list_add(&v9ses->slist, &v9fs_sessionlist);
489 	spin_unlock(&v9fs_sessionlist_lock);
490 
491 	return fid;
492 
493 err_clnt:
494 #ifdef CONFIG_9P_FSCACHE
495 	kfree(v9ses->cachetag);
496 #endif
497 	p9_client_destroy(v9ses->clnt);
498 err_names:
499 	kfree(v9ses->uname);
500 	kfree(v9ses->aname);
501 	return ERR_PTR(rc);
502 }
503 
504 /**
505  * v9fs_session_close - shutdown a session
506  * @v9ses: session information structure
507  *
508  */
509 
510 void v9fs_session_close(struct v9fs_session_info *v9ses)
511 {
512 	if (v9ses->clnt) {
513 		p9_client_destroy(v9ses->clnt);
514 		v9ses->clnt = NULL;
515 	}
516 
517 #ifdef CONFIG_9P_FSCACHE
518 	if (v9ses->fscache) {
519 		v9fs_cache_session_put_cookie(v9ses);
520 		kfree(v9ses->cachetag);
521 	}
522 #endif
523 	kfree(v9ses->uname);
524 	kfree(v9ses->aname);
525 
526 	spin_lock(&v9fs_sessionlist_lock);
527 	list_del(&v9ses->slist);
528 	spin_unlock(&v9fs_sessionlist_lock);
529 }
530 
531 /**
532  * v9fs_session_cancel - terminate a session
533  * @v9ses: session to terminate
534  *
535  * mark transport as disconnected and cancel all pending requests.
536  */
537 
538 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
539 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
540 	p9_client_disconnect(v9ses->clnt);
541 }
542 
543 /**
544  * v9fs_session_begin_cancel - Begin terminate of a session
545  * @v9ses: session to terminate
546  *
547  * After this call we don't allow any request other than clunk.
548  */
549 
550 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
551 {
552 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
553 	p9_client_begin_disconnect(v9ses->clnt);
554 }
555 
556 extern int v9fs_error_init(void);
557 
558 static struct kobject *v9fs_kobj;
559 
560 #ifdef CONFIG_9P_FSCACHE
561 /**
562  * caches_show - list caches associated with a session
563  *
564  * Returns the size of buffer written.
565  */
566 
567 static ssize_t caches_show(struct kobject *kobj,
568 			   struct kobj_attribute *attr,
569 			   char *buf)
570 {
571 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
572 	struct v9fs_session_info *v9ses;
573 
574 	spin_lock(&v9fs_sessionlist_lock);
575 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
576 		if (v9ses->cachetag) {
577 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
578 			if (n < 0) {
579 				count = n;
580 				break;
581 			}
582 
583 			count += n;
584 			limit -= n;
585 		}
586 	}
587 
588 	spin_unlock(&v9fs_sessionlist_lock);
589 	return count;
590 }
591 
592 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
593 #endif /* CONFIG_9P_FSCACHE */
594 
595 static struct attribute *v9fs_attrs[] = {
596 #ifdef CONFIG_9P_FSCACHE
597 	&v9fs_attr_cache.attr,
598 #endif
599 	NULL,
600 };
601 
602 static struct attribute_group v9fs_attr_group = {
603 	.attrs = v9fs_attrs,
604 };
605 
606 /**
607  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
608  *
609  */
610 
611 static int __init v9fs_sysfs_init(void)
612 {
613 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
614 	if (!v9fs_kobj)
615 		return -ENOMEM;
616 
617 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
618 		kobject_put(v9fs_kobj);
619 		return -ENOMEM;
620 	}
621 
622 	return 0;
623 }
624 
625 /**
626  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
627  *
628  */
629 
630 static void v9fs_sysfs_cleanup(void)
631 {
632 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
633 	kobject_put(v9fs_kobj);
634 }
635 
636 static void v9fs_inode_init_once(void *foo)
637 {
638 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
639 #ifdef CONFIG_9P_FSCACHE
640 	v9inode->fscache = NULL;
641 #endif
642 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
643 	inode_init_once(&v9inode->vfs_inode);
644 }
645 
646 /**
647  * v9fs_init_inode_cache - initialize a cache for 9P
648  * Returns 0 on success.
649  */
650 static int v9fs_init_inode_cache(void)
651 {
652 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
653 					  sizeof(struct v9fs_inode),
654 					  0, (SLAB_RECLAIM_ACCOUNT|
655 					      SLAB_MEM_SPREAD|SLAB_ACCOUNT),
656 					  v9fs_inode_init_once);
657 	if (!v9fs_inode_cache)
658 		return -ENOMEM;
659 
660 	return 0;
661 }
662 
663 /**
664  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
665  *
666  */
667 static void v9fs_destroy_inode_cache(void)
668 {
669 	/*
670 	 * Make sure all delayed rcu free inodes are flushed before we
671 	 * destroy cache.
672 	 */
673 	rcu_barrier();
674 	kmem_cache_destroy(v9fs_inode_cache);
675 }
676 
677 static int v9fs_cache_register(void)
678 {
679 	int ret;
680 	ret = v9fs_init_inode_cache();
681 	if (ret < 0)
682 		return ret;
683 #ifdef CONFIG_9P_FSCACHE
684 	ret = fscache_register_netfs(&v9fs_cache_netfs);
685 	if (ret < 0)
686 		v9fs_destroy_inode_cache();
687 #endif
688 	return ret;
689 }
690 
691 static void v9fs_cache_unregister(void)
692 {
693 	v9fs_destroy_inode_cache();
694 #ifdef CONFIG_9P_FSCACHE
695 	fscache_unregister_netfs(&v9fs_cache_netfs);
696 #endif
697 }
698 
699 /**
700  * init_v9fs - Initialize module
701  *
702  */
703 
704 static int __init init_v9fs(void)
705 {
706 	int err;
707 	pr_info("Installing v9fs 9p2000 file system support\n");
708 	/* TODO: Setup list of registered trasnport modules */
709 
710 	err = v9fs_cache_register();
711 	if (err < 0) {
712 		pr_err("Failed to register v9fs for caching\n");
713 		return err;
714 	}
715 
716 	err = v9fs_sysfs_init();
717 	if (err < 0) {
718 		pr_err("Failed to register with sysfs\n");
719 		goto out_cache;
720 	}
721 	err = register_filesystem(&v9fs_fs_type);
722 	if (err < 0) {
723 		pr_err("Failed to register filesystem\n");
724 		goto out_sysfs_cleanup;
725 	}
726 
727 	return 0;
728 
729 out_sysfs_cleanup:
730 	v9fs_sysfs_cleanup();
731 
732 out_cache:
733 	v9fs_cache_unregister();
734 
735 	return err;
736 }
737 
738 /**
739  * exit_v9fs - shutdown module
740  *
741  */
742 
743 static void __exit exit_v9fs(void)
744 {
745 	v9fs_sysfs_cleanup();
746 	v9fs_cache_unregister();
747 	unregister_filesystem(&v9fs_fs_type);
748 }
749 
750 module_init(init_v9fs)
751 module_exit(exit_v9fs)
752 
753 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
754 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
755 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
756 MODULE_LICENSE("GPL");
757