xref: /openbmc/linux/fs/9p/v9fs.c (revision 5bd8e16d) 
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 */
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 
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 = make_kuid(current_user_ns(), option);
165 			if (!uid_valid(v9ses->dfltuid)) {
166 				p9_debug(P9_DEBUG_ERROR,
167 					 "uid field, but not a uid?\n");
168 				ret = -EINVAL;
169 				continue;
170 			}
171 			break;
172 		case Opt_dfltgid:
173 			r = match_int(&args[0], &option);
174 			if (r < 0) {
175 				p9_debug(P9_DEBUG_ERROR,
176 					 "integer field, but no integer?\n");
177 				ret = r;
178 				continue;
179 			}
180 			v9ses->dfltgid = make_kgid(current_user_ns(), option);
181 			if (!gid_valid(v9ses->dfltgid)) {
182 				p9_debug(P9_DEBUG_ERROR,
183 					 "gid field, but not a gid?\n");
184 				ret = -EINVAL;
185 				continue;
186 			}
187 			break;
188 		case Opt_afid:
189 			r = match_int(&args[0], &option);
190 			if (r < 0) {
191 				p9_debug(P9_DEBUG_ERROR,
192 					 "integer field, but no integer?\n");
193 				ret = r;
194 				continue;
195 			}
196 			v9ses->afid = option;
197 			break;
198 		case Opt_uname:
199 			kfree(v9ses->uname);
200 			v9ses->uname = match_strdup(&args[0]);
201 			if (!v9ses->uname) {
202 				ret = -ENOMEM;
203 				goto free_and_return;
204 			}
205 			break;
206 		case Opt_remotename:
207 			kfree(v9ses->aname);
208 			v9ses->aname = match_strdup(&args[0]);
209 			if (!v9ses->aname) {
210 				ret = -ENOMEM;
211 				goto free_and_return;
212 			}
213 			break;
214 		case Opt_nodevmap:
215 			v9ses->nodev = 1;
216 			break;
217 		case Opt_cache_loose:
218 			v9ses->cache = CACHE_LOOSE;
219 			break;
220 		case Opt_fscache:
221 			v9ses->cache = CACHE_FSCACHE;
222 			break;
223 		case Opt_cachetag:
224 #ifdef CONFIG_9P_FSCACHE
225 			v9ses->cachetag = match_strdup(&args[0]);
226 #endif
227 			break;
228 		case Opt_cache:
229 			s = match_strdup(&args[0]);
230 			if (!s) {
231 				ret = -ENOMEM;
232 				p9_debug(P9_DEBUG_ERROR,
233 					 "problem allocating copy of cache arg\n");
234 				goto free_and_return;
235 			}
236 			ret = get_cache_mode(s);
237 			if (ret == -EINVAL) {
238 				kfree(s);
239 				goto free_and_return;
240 			}
241 
242 			v9ses->cache = ret;
243 			kfree(s);
244 			break;
245 
246 		case Opt_access:
247 			s = match_strdup(&args[0]);
248 			if (!s) {
249 				ret = -ENOMEM;
250 				p9_debug(P9_DEBUG_ERROR,
251 					 "problem allocating copy of access arg\n");
252 				goto free_and_return;
253 			}
254 
255 			v9ses->flags &= ~V9FS_ACCESS_MASK;
256 			if (strcmp(s, "user") == 0)
257 				v9ses->flags |= V9FS_ACCESS_USER;
258 			else if (strcmp(s, "any") == 0)
259 				v9ses->flags |= V9FS_ACCESS_ANY;
260 			else if (strcmp(s, "client") == 0) {
261 				v9ses->flags |= V9FS_ACCESS_CLIENT;
262 			} else {
263 				uid_t uid;
264 				v9ses->flags |= V9FS_ACCESS_SINGLE;
265 				uid = simple_strtoul(s, &e, 10);
266 				if (*e != '\0') {
267 					ret = -EINVAL;
268 					pr_info("Unknown access argument %s\n",
269 						s);
270 					kfree(s);
271 					goto free_and_return;
272 				}
273 				v9ses->uid = make_kuid(current_user_ns(), uid);
274 				if (!uid_valid(v9ses->uid)) {
275 					ret = -EINVAL;
276 					pr_info("Uknown uid %s\n", s);
277 					kfree(s);
278 					goto free_and_return;
279 				}
280 			}
281 
282 			kfree(s);
283 			break;
284 
285 		case Opt_posixacl:
286 #ifdef CONFIG_9P_FS_POSIX_ACL
287 			v9ses->flags |= V9FS_POSIX_ACL;
288 #else
289 			p9_debug(P9_DEBUG_ERROR,
290 				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
291 #endif
292 			break;
293 
294 		default:
295 			continue;
296 		}
297 	}
298 
299 free_and_return:
300 	kfree(tmp_options);
301 fail_option_alloc:
302 	return ret;
303 }
304 
305 /**
306  * v9fs_session_init - initialize session
307  * @v9ses: session information structure
308  * @dev_name: device being mounted
309  * @data: options
310  *
311  */
312 
313 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
314 		  const char *dev_name, char *data)
315 {
316 	int retval = -EINVAL;
317 	struct p9_fid *fid;
318 	int rc;
319 
320 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
321 	if (!v9ses->uname)
322 		return ERR_PTR(-ENOMEM);
323 
324 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
325 	if (!v9ses->aname) {
326 		kfree(v9ses->uname);
327 		return ERR_PTR(-ENOMEM);
328 	}
329 	init_rwsem(&v9ses->rename_sem);
330 
331 	rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
332 	if (rc) {
333 		kfree(v9ses->aname);
334 		kfree(v9ses->uname);
335 		return ERR_PTR(rc);
336 	}
337 
338 	spin_lock(&v9fs_sessionlist_lock);
339 	list_add(&v9ses->slist, &v9fs_sessionlist);
340 	spin_unlock(&v9fs_sessionlist_lock);
341 
342 	v9ses->uid = INVALID_UID;
343 	v9ses->dfltuid = V9FS_DEFUID;
344 	v9ses->dfltgid = V9FS_DEFGID;
345 
346 	v9ses->clnt = p9_client_create(dev_name, data);
347 	if (IS_ERR(v9ses->clnt)) {
348 		retval = PTR_ERR(v9ses->clnt);
349 		v9ses->clnt = NULL;
350 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
351 		goto error;
352 	}
353 
354 	v9ses->flags = V9FS_ACCESS_USER;
355 
356 	if (p9_is_proto_dotl(v9ses->clnt)) {
357 		v9ses->flags = V9FS_ACCESS_CLIENT;
358 		v9ses->flags |= V9FS_PROTO_2000L;
359 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
360 		v9ses->flags |= V9FS_PROTO_2000U;
361 	}
362 
363 	rc = v9fs_parse_options(v9ses, data);
364 	if (rc < 0) {
365 		retval = rc;
366 		goto error;
367 	}
368 
369 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
370 
371 	if (!v9fs_proto_dotl(v9ses) &&
372 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
373 		/*
374 		 * We support ACCESS_CLIENT only for dotl.
375 		 * Fall back to ACCESS_USER
376 		 */
377 		v9ses->flags &= ~V9FS_ACCESS_MASK;
378 		v9ses->flags |= V9FS_ACCESS_USER;
379 	}
380 	/*FIXME !! */
381 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
382 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
383 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
384 
385 		v9ses->flags &= ~V9FS_ACCESS_MASK;
386 		v9ses->flags |= V9FS_ACCESS_ANY;
387 		v9ses->uid = INVALID_UID;
388 	}
389 	if (!v9fs_proto_dotl(v9ses) ||
390 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
391 		/*
392 		 * We support ACL checks on clinet only if the protocol is
393 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
394 		 */
395 		v9ses->flags &= ~V9FS_ACL_MASK;
396 	}
397 
398 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
399 							v9ses->aname);
400 	if (IS_ERR(fid)) {
401 		retval = PTR_ERR(fid);
402 		fid = NULL;
403 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
404 		goto error;
405 	}
406 
407 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
408 		fid->uid = v9ses->uid;
409 	else
410 		fid->uid = INVALID_UID;
411 
412 #ifdef CONFIG_9P_FSCACHE
413 	/* register the session for caching */
414 	v9fs_cache_session_get_cookie(v9ses);
415 #endif
416 
417 	return fid;
418 
419 error:
420 	bdi_destroy(&v9ses->bdi);
421 	return ERR_PTR(retval);
422 }
423 
424 /**
425  * v9fs_session_close - shutdown a session
426  * @v9ses: session information structure
427  *
428  */
429 
430 void v9fs_session_close(struct v9fs_session_info *v9ses)
431 {
432 	if (v9ses->clnt) {
433 		p9_client_destroy(v9ses->clnt);
434 		v9ses->clnt = NULL;
435 	}
436 
437 #ifdef CONFIG_9P_FSCACHE
438 	if (v9ses->fscache) {
439 		v9fs_cache_session_put_cookie(v9ses);
440 		kfree(v9ses->cachetag);
441 	}
442 #endif
443 	kfree(v9ses->uname);
444 	kfree(v9ses->aname);
445 
446 	bdi_destroy(&v9ses->bdi);
447 
448 	spin_lock(&v9fs_sessionlist_lock);
449 	list_del(&v9ses->slist);
450 	spin_unlock(&v9fs_sessionlist_lock);
451 }
452 
453 /**
454  * v9fs_session_cancel - terminate a session
455  * @v9ses: session to terminate
456  *
457  * mark transport as disconnected and cancel all pending requests.
458  */
459 
460 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
461 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
462 	p9_client_disconnect(v9ses->clnt);
463 }
464 
465 /**
466  * v9fs_session_begin_cancel - Begin terminate of a session
467  * @v9ses: session to terminate
468  *
469  * After this call we don't allow any request other than clunk.
470  */
471 
472 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
473 {
474 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
475 	p9_client_begin_disconnect(v9ses->clnt);
476 }
477 
478 extern int v9fs_error_init(void);
479 
480 static struct kobject *v9fs_kobj;
481 
482 #ifdef CONFIG_9P_FSCACHE
483 /**
484  * caches_show - list caches associated with a session
485  *
486  * Returns the size of buffer written.
487  */
488 
489 static ssize_t caches_show(struct kobject *kobj,
490 			   struct kobj_attribute *attr,
491 			   char *buf)
492 {
493 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
494 	struct v9fs_session_info *v9ses;
495 
496 	spin_lock(&v9fs_sessionlist_lock);
497 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
498 		if (v9ses->cachetag) {
499 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
500 			if (n < 0) {
501 				count = n;
502 				break;
503 			}
504 
505 			count += n;
506 			limit -= n;
507 		}
508 	}
509 
510 	spin_unlock(&v9fs_sessionlist_lock);
511 	return count;
512 }
513 
514 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
515 #endif /* CONFIG_9P_FSCACHE */
516 
517 static struct attribute *v9fs_attrs[] = {
518 #ifdef CONFIG_9P_FSCACHE
519 	&v9fs_attr_cache.attr,
520 #endif
521 	NULL,
522 };
523 
524 static struct attribute_group v9fs_attr_group = {
525 	.attrs = v9fs_attrs,
526 };
527 
528 /**
529  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
530  *
531  */
532 
533 static int v9fs_sysfs_init(void)
534 {
535 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
536 	if (!v9fs_kobj)
537 		return -ENOMEM;
538 
539 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
540 		kobject_put(v9fs_kobj);
541 		return -ENOMEM;
542 	}
543 
544 	return 0;
545 }
546 
547 /**
548  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
549  *
550  */
551 
552 static void v9fs_sysfs_cleanup(void)
553 {
554 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
555 	kobject_put(v9fs_kobj);
556 }
557 
558 static void v9fs_inode_init_once(void *foo)
559 {
560 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
561 #ifdef CONFIG_9P_FSCACHE
562 	v9inode->fscache = NULL;
563 #endif
564 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
565 	inode_init_once(&v9inode->vfs_inode);
566 }
567 
568 /**
569  * v9fs_init_inode_cache - initialize a cache for 9P
570  * Returns 0 on success.
571  */
572 static int v9fs_init_inode_cache(void)
573 {
574 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
575 					  sizeof(struct v9fs_inode),
576 					  0, (SLAB_RECLAIM_ACCOUNT|
577 					      SLAB_MEM_SPREAD),
578 					  v9fs_inode_init_once);
579 	if (!v9fs_inode_cache)
580 		return -ENOMEM;
581 
582 	return 0;
583 }
584 
585 /**
586  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
587  *
588  */
589 static void v9fs_destroy_inode_cache(void)
590 {
591 	/*
592 	 * Make sure all delayed rcu free inodes are flushed before we
593 	 * destroy cache.
594 	 */
595 	rcu_barrier();
596 	kmem_cache_destroy(v9fs_inode_cache);
597 }
598 
599 static int v9fs_cache_register(void)
600 {
601 	int ret;
602 	ret = v9fs_init_inode_cache();
603 	if (ret < 0)
604 		return ret;
605 #ifdef CONFIG_9P_FSCACHE
606 	ret = fscache_register_netfs(&v9fs_cache_netfs);
607 	if (ret < 0)
608 		v9fs_destroy_inode_cache();
609 #endif
610 	return ret;
611 }
612 
613 static void v9fs_cache_unregister(void)
614 {
615 	v9fs_destroy_inode_cache();
616 #ifdef CONFIG_9P_FSCACHE
617 	fscache_unregister_netfs(&v9fs_cache_netfs);
618 #endif
619 }
620 
621 /**
622  * init_v9fs - Initialize module
623  *
624  */
625 
626 static int __init init_v9fs(void)
627 {
628 	int err;
629 	pr_info("Installing v9fs 9p2000 file system support\n");
630 	/* TODO: Setup list of registered trasnport modules */
631 
632 	err = v9fs_cache_register();
633 	if (err < 0) {
634 		pr_err("Failed to register v9fs for caching\n");
635 		return err;
636 	}
637 
638 	err = v9fs_sysfs_init();
639 	if (err < 0) {
640 		pr_err("Failed to register with sysfs\n");
641 		goto out_cache;
642 	}
643 	err = register_filesystem(&v9fs_fs_type);
644 	if (err < 0) {
645 		pr_err("Failed to register filesystem\n");
646 		goto out_sysfs_cleanup;
647 	}
648 
649 	return 0;
650 
651 out_sysfs_cleanup:
652 	v9fs_sysfs_cleanup();
653 
654 out_cache:
655 	v9fs_cache_unregister();
656 
657 	return err;
658 }
659 
660 /**
661  * exit_v9fs - shutdown module
662  *
663  */
664 
665 static void __exit exit_v9fs(void)
666 {
667 	v9fs_sysfs_cleanup();
668 	v9fs_cache_unregister();
669 	unregister_filesystem(&v9fs_fs_type);
670 }
671 
672 module_init(init_v9fs)
673 module_exit(exit_v9fs)
674 
675 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
676 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
677 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
678 MODULE_LICENSE("GPL");
679