xref: /openbmc/linux/fs/9p/v9fs.c (revision e992ef57) 
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 <net/9p/9p.h>
37 #include <net/9p/client.h>
38 #include <net/9p/transport.h>
39 #include "v9fs.h"
40 #include "v9fs_vfs.h"
41 #include "cache.h"
42 
43 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
44 static LIST_HEAD(v9fs_sessionlist);
45 struct kmem_cache *v9fs_inode_cache;
46 
47 /*
48  * Option Parsing (code inspired by NFS code)
49  *  NOTE: each transport will parse its own options
50  */
51 
52 enum {
53 	/* Options that take integer arguments */
54 	Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
55 	/* String options */
56 	Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
57 	/* Options that take no arguments */
58 	Opt_nodevmap,
59 	/* Cache options */
60 	Opt_cache_loose, Opt_fscache, Opt_mmap,
61 	/* Access options */
62 	Opt_access, Opt_posixacl,
63 	/* Error token */
64 	Opt_err
65 };
66 
67 static const match_table_t tokens = {
68 	{Opt_debug, "debug=%x"},
69 	{Opt_dfltuid, "dfltuid=%u"},
70 	{Opt_dfltgid, "dfltgid=%u"},
71 	{Opt_afid, "afid=%u"},
72 	{Opt_uname, "uname=%s"},
73 	{Opt_remotename, "aname=%s"},
74 	{Opt_nodevmap, "nodevmap"},
75 	{Opt_cache, "cache=%s"},
76 	{Opt_cache_loose, "loose"},
77 	{Opt_fscache, "fscache"},
78 	{Opt_mmap, "mmap"},
79 	{Opt_cachetag, "cachetag=%s"},
80 	{Opt_access, "access=%s"},
81 	{Opt_posixacl, "posixacl"},
82 	{Opt_err, NULL}
83 };
84 
85 /* Interpret mount options for cache mode */
86 static int get_cache_mode(char *s)
87 {
88 	int version = -EINVAL;
89 
90 	if (!strcmp(s, "loose")) {
91 		version = CACHE_LOOSE;
92 		p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
93 	} else if (!strcmp(s, "fscache")) {
94 		version = CACHE_FSCACHE;
95 		p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
96 	} else if (!strcmp(s, "mmap")) {
97 		version = CACHE_MMAP;
98 		p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
99 	} else if (!strcmp(s, "none")) {
100 		version = CACHE_NONE;
101 		p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
102 	} else
103 		pr_info("Unknown Cache mode %s\n", s);
104 	return version;
105 }
106 
107 /**
108  * v9fs_parse_options - parse mount options into session structure
109  * @v9ses: existing v9fs session information
110  *
111  * Return 0 upon success, -ERRNO upon failure.
112  */
113 
114 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
115 {
116 	char *options, *tmp_options;
117 	substring_t args[MAX_OPT_ARGS];
118 	char *p;
119 	int option = 0;
120 	char *s, *e;
121 	int ret = 0;
122 
123 	/* setup defaults */
124 	v9ses->afid = ~0;
125 	v9ses->debug = 0;
126 	v9ses->cache = CACHE_NONE;
127 #ifdef CONFIG_9P_FSCACHE
128 	v9ses->cachetag = NULL;
129 #endif
130 
131 	if (!opts)
132 		return 0;
133 
134 	tmp_options = kstrdup(opts, GFP_KERNEL);
135 	if (!tmp_options) {
136 		ret = -ENOMEM;
137 		goto fail_option_alloc;
138 	}
139 	options = tmp_options;
140 
141 	while ((p = strsep(&options, ",")) != NULL) {
142 		int token, r;
143 		if (!*p)
144 			continue;
145 		token = match_token(p, tokens, args);
146 		switch (token) {
147 		case Opt_debug:
148 			r = match_int(&args[0], &option);
149 			if (r < 0) {
150 				p9_debug(P9_DEBUG_ERROR,
151 					 "integer field, but no integer?\n");
152 				ret = r;
153 				continue;
154 			}
155 			v9ses->debug = option;
156 #ifdef CONFIG_NET_9P_DEBUG
157 			p9_debug_level = option;
158 #endif
159 			break;
160 
161 		case Opt_dfltuid:
162 			r = match_int(&args[0], &option);
163 			if (r < 0) {
164 				p9_debug(P9_DEBUG_ERROR,
165 					 "integer field, but no integer?\n");
166 				ret = r;
167 				continue;
168 			}
169 			v9ses->dfltuid = make_kuid(current_user_ns(), option);
170 			if (!uid_valid(v9ses->dfltuid)) {
171 				p9_debug(P9_DEBUG_ERROR,
172 					 "uid field, but not a uid?\n");
173 				ret = -EINVAL;
174 				continue;
175 			}
176 			break;
177 		case Opt_dfltgid:
178 			r = match_int(&args[0], &option);
179 			if (r < 0) {
180 				p9_debug(P9_DEBUG_ERROR,
181 					 "integer field, but no integer?\n");
182 				ret = r;
183 				continue;
184 			}
185 			v9ses->dfltgid = make_kgid(current_user_ns(), option);
186 			if (!gid_valid(v9ses->dfltgid)) {
187 				p9_debug(P9_DEBUG_ERROR,
188 					 "gid field, but not a gid?\n");
189 				ret = -EINVAL;
190 				continue;
191 			}
192 			break;
193 		case Opt_afid:
194 			r = match_int(&args[0], &option);
195 			if (r < 0) {
196 				p9_debug(P9_DEBUG_ERROR,
197 					 "integer field, but no integer?\n");
198 				ret = r;
199 				continue;
200 			}
201 			v9ses->afid = option;
202 			break;
203 		case Opt_uname:
204 			kfree(v9ses->uname);
205 			v9ses->uname = match_strdup(&args[0]);
206 			if (!v9ses->uname) {
207 				ret = -ENOMEM;
208 				goto free_and_return;
209 			}
210 			break;
211 		case Opt_remotename:
212 			kfree(v9ses->aname);
213 			v9ses->aname = match_strdup(&args[0]);
214 			if (!v9ses->aname) {
215 				ret = -ENOMEM;
216 				goto free_and_return;
217 			}
218 			break;
219 		case Opt_nodevmap:
220 			v9ses->nodev = 1;
221 			break;
222 		case Opt_cache_loose:
223 			v9ses->cache = CACHE_LOOSE;
224 			break;
225 		case Opt_fscache:
226 			v9ses->cache = CACHE_FSCACHE;
227 			break;
228 		case Opt_mmap:
229 			v9ses->cache = CACHE_MMAP;
230 			break;
231 		case Opt_cachetag:
232 #ifdef CONFIG_9P_FSCACHE
233 			v9ses->cachetag = match_strdup(&args[0]);
234 #endif
235 			break;
236 		case Opt_cache:
237 			s = match_strdup(&args[0]);
238 			if (!s) {
239 				ret = -ENOMEM;
240 				p9_debug(P9_DEBUG_ERROR,
241 					 "problem allocating copy of cache arg\n");
242 				goto free_and_return;
243 			}
244 			ret = get_cache_mode(s);
245 			if (ret == -EINVAL) {
246 				kfree(s);
247 				goto free_and_return;
248 			}
249 
250 			v9ses->cache = ret;
251 			kfree(s);
252 			break;
253 
254 		case Opt_access:
255 			s = match_strdup(&args[0]);
256 			if (!s) {
257 				ret = -ENOMEM;
258 				p9_debug(P9_DEBUG_ERROR,
259 					 "problem allocating copy of access arg\n");
260 				goto free_and_return;
261 			}
262 
263 			v9ses->flags &= ~V9FS_ACCESS_MASK;
264 			if (strcmp(s, "user") == 0)
265 				v9ses->flags |= V9FS_ACCESS_USER;
266 			else if (strcmp(s, "any") == 0)
267 				v9ses->flags |= V9FS_ACCESS_ANY;
268 			else if (strcmp(s, "client") == 0) {
269 				v9ses->flags |= V9FS_ACCESS_CLIENT;
270 			} else {
271 				uid_t uid;
272 				v9ses->flags |= V9FS_ACCESS_SINGLE;
273 				uid = simple_strtoul(s, &e, 10);
274 				if (*e != '\0') {
275 					ret = -EINVAL;
276 					pr_info("Unknown access argument %s\n",
277 						s);
278 					kfree(s);
279 					goto free_and_return;
280 				}
281 				v9ses->uid = make_kuid(current_user_ns(), uid);
282 				if (!uid_valid(v9ses->uid)) {
283 					ret = -EINVAL;
284 					pr_info("Uknown uid %s\n", s);
285 					kfree(s);
286 					goto free_and_return;
287 				}
288 			}
289 
290 			kfree(s);
291 			break;
292 
293 		case Opt_posixacl:
294 #ifdef CONFIG_9P_FS_POSIX_ACL
295 			v9ses->flags |= V9FS_POSIX_ACL;
296 #else
297 			p9_debug(P9_DEBUG_ERROR,
298 				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
299 #endif
300 			break;
301 
302 		default:
303 			continue;
304 		}
305 	}
306 
307 free_and_return:
308 	kfree(tmp_options);
309 fail_option_alloc:
310 	return ret;
311 }
312 
313 /**
314  * v9fs_session_init - initialize session
315  * @v9ses: session information structure
316  * @dev_name: device being mounted
317  * @data: options
318  *
319  */
320 
321 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
322 		  const char *dev_name, char *data)
323 {
324 	struct p9_fid *fid;
325 	int rc = -ENOMEM;
326 
327 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
328 	if (!v9ses->uname)
329 		goto err_names;
330 
331 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
332 	if (!v9ses->aname)
333 		goto err_names;
334 	init_rwsem(&v9ses->rename_sem);
335 
336 	rc = bdi_setup_and_register(&v9ses->bdi, "9p");
337 	if (rc)
338 		goto err_names;
339 
340 	v9ses->uid = INVALID_UID;
341 	v9ses->dfltuid = V9FS_DEFUID;
342 	v9ses->dfltgid = V9FS_DEFGID;
343 
344 	v9ses->clnt = p9_client_create(dev_name, data);
345 	if (IS_ERR(v9ses->clnt)) {
346 		rc = PTR_ERR(v9ses->clnt);
347 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
348 		goto err_bdi;
349 	}
350 
351 	v9ses->flags = V9FS_ACCESS_USER;
352 
353 	if (p9_is_proto_dotl(v9ses->clnt)) {
354 		v9ses->flags = V9FS_ACCESS_CLIENT;
355 		v9ses->flags |= V9FS_PROTO_2000L;
356 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
357 		v9ses->flags |= V9FS_PROTO_2000U;
358 	}
359 
360 	rc = v9fs_parse_options(v9ses, data);
361 	if (rc < 0)
362 		goto err_clnt;
363 
364 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
365 
366 	if (!v9fs_proto_dotl(v9ses) &&
367 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
368 		/*
369 		 * We support ACCESS_CLIENT only for dotl.
370 		 * Fall back to ACCESS_USER
371 		 */
372 		v9ses->flags &= ~V9FS_ACCESS_MASK;
373 		v9ses->flags |= V9FS_ACCESS_USER;
374 	}
375 	/*FIXME !! */
376 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
377 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
378 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
379 
380 		v9ses->flags &= ~V9FS_ACCESS_MASK;
381 		v9ses->flags |= V9FS_ACCESS_ANY;
382 		v9ses->uid = INVALID_UID;
383 	}
384 	if (!v9fs_proto_dotl(v9ses) ||
385 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
386 		/*
387 		 * We support ACL checks on clinet only if the protocol is
388 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
389 		 */
390 		v9ses->flags &= ~V9FS_ACL_MASK;
391 	}
392 
393 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
394 							v9ses->aname);
395 	if (IS_ERR(fid)) {
396 		rc = PTR_ERR(fid);
397 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
398 		goto err_clnt;
399 	}
400 
401 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
402 		fid->uid = v9ses->uid;
403 	else
404 		fid->uid = INVALID_UID;
405 
406 #ifdef CONFIG_9P_FSCACHE
407 	/* register the session for caching */
408 	v9fs_cache_session_get_cookie(v9ses);
409 #endif
410 	spin_lock(&v9fs_sessionlist_lock);
411 	list_add(&v9ses->slist, &v9fs_sessionlist);
412 	spin_unlock(&v9fs_sessionlist_lock);
413 
414 	return fid;
415 
416 err_clnt:
417 	p9_client_destroy(v9ses->clnt);
418 err_bdi:
419 	bdi_destroy(&v9ses->bdi);
420 err_names:
421 	kfree(v9ses->uname);
422 	kfree(v9ses->aname);
423 	return ERR_PTR(rc);
424 }
425 
426 /**
427  * v9fs_session_close - shutdown a session
428  * @v9ses: session information structure
429  *
430  */
431 
432 void v9fs_session_close(struct v9fs_session_info *v9ses)
433 {
434 	if (v9ses->clnt) {
435 		p9_client_destroy(v9ses->clnt);
436 		v9ses->clnt = NULL;
437 	}
438 
439 #ifdef CONFIG_9P_FSCACHE
440 	if (v9ses->fscache) {
441 		v9fs_cache_session_put_cookie(v9ses);
442 		kfree(v9ses->cachetag);
443 	}
444 #endif
445 	kfree(v9ses->uname);
446 	kfree(v9ses->aname);
447 
448 	bdi_destroy(&v9ses->bdi);
449 
450 	spin_lock(&v9fs_sessionlist_lock);
451 	list_del(&v9ses->slist);
452 	spin_unlock(&v9fs_sessionlist_lock);
453 }
454 
455 /**
456  * v9fs_session_cancel - terminate a session
457  * @v9ses: session to terminate
458  *
459  * mark transport as disconnected and cancel all pending requests.
460  */
461 
462 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
463 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
464 	p9_client_disconnect(v9ses->clnt);
465 }
466 
467 /**
468  * v9fs_session_begin_cancel - Begin terminate of a session
469  * @v9ses: session to terminate
470  *
471  * After this call we don't allow any request other than clunk.
472  */
473 
474 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
475 {
476 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
477 	p9_client_begin_disconnect(v9ses->clnt);
478 }
479 
480 extern int v9fs_error_init(void);
481 
482 static struct kobject *v9fs_kobj;
483 
484 #ifdef CONFIG_9P_FSCACHE
485 /**
486  * caches_show - list caches associated with a session
487  *
488  * Returns the size of buffer written.
489  */
490 
491 static ssize_t caches_show(struct kobject *kobj,
492 			   struct kobj_attribute *attr,
493 			   char *buf)
494 {
495 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
496 	struct v9fs_session_info *v9ses;
497 
498 	spin_lock(&v9fs_sessionlist_lock);
499 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
500 		if (v9ses->cachetag) {
501 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
502 			if (n < 0) {
503 				count = n;
504 				break;
505 			}
506 
507 			count += n;
508 			limit -= n;
509 		}
510 	}
511 
512 	spin_unlock(&v9fs_sessionlist_lock);
513 	return count;
514 }
515 
516 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
517 #endif /* CONFIG_9P_FSCACHE */
518 
519 static struct attribute *v9fs_attrs[] = {
520 #ifdef CONFIG_9P_FSCACHE
521 	&v9fs_attr_cache.attr,
522 #endif
523 	NULL,
524 };
525 
526 static struct attribute_group v9fs_attr_group = {
527 	.attrs = v9fs_attrs,
528 };
529 
530 /**
531  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
532  *
533  */
534 
535 static int __init v9fs_sysfs_init(void)
536 {
537 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
538 	if (!v9fs_kobj)
539 		return -ENOMEM;
540 
541 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
542 		kobject_put(v9fs_kobj);
543 		return -ENOMEM;
544 	}
545 
546 	return 0;
547 }
548 
549 /**
550  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
551  *
552  */
553 
554 static void v9fs_sysfs_cleanup(void)
555 {
556 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
557 	kobject_put(v9fs_kobj);
558 }
559 
560 static void v9fs_inode_init_once(void *foo)
561 {
562 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
563 #ifdef CONFIG_9P_FSCACHE
564 	v9inode->fscache = NULL;
565 #endif
566 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
567 	inode_init_once(&v9inode->vfs_inode);
568 }
569 
570 /**
571  * v9fs_init_inode_cache - initialize a cache for 9P
572  * Returns 0 on success.
573  */
574 static int v9fs_init_inode_cache(void)
575 {
576 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
577 					  sizeof(struct v9fs_inode),
578 					  0, (SLAB_RECLAIM_ACCOUNT|
579 					      SLAB_MEM_SPREAD|SLAB_ACCOUNT),
580 					  v9fs_inode_init_once);
581 	if (!v9fs_inode_cache)
582 		return -ENOMEM;
583 
584 	return 0;
585 }
586 
587 /**
588  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
589  *
590  */
591 static void v9fs_destroy_inode_cache(void)
592 {
593 	/*
594 	 * Make sure all delayed rcu free inodes are flushed before we
595 	 * destroy cache.
596 	 */
597 	rcu_barrier();
598 	kmem_cache_destroy(v9fs_inode_cache);
599 }
600 
601 static int v9fs_cache_register(void)
602 {
603 	int ret;
604 	ret = v9fs_init_inode_cache();
605 	if (ret < 0)
606 		return ret;
607 #ifdef CONFIG_9P_FSCACHE
608 	ret = fscache_register_netfs(&v9fs_cache_netfs);
609 	if (ret < 0)
610 		v9fs_destroy_inode_cache();
611 #endif
612 	return ret;
613 }
614 
615 static void v9fs_cache_unregister(void)
616 {
617 	v9fs_destroy_inode_cache();
618 #ifdef CONFIG_9P_FSCACHE
619 	fscache_unregister_netfs(&v9fs_cache_netfs);
620 #endif
621 }
622 
623 /**
624  * init_v9fs - Initialize module
625  *
626  */
627 
628 static int __init init_v9fs(void)
629 {
630 	int err;
631 	pr_info("Installing v9fs 9p2000 file system support\n");
632 	/* TODO: Setup list of registered trasnport modules */
633 
634 	err = v9fs_cache_register();
635 	if (err < 0) {
636 		pr_err("Failed to register v9fs for caching\n");
637 		return err;
638 	}
639 
640 	err = v9fs_sysfs_init();
641 	if (err < 0) {
642 		pr_err("Failed to register with sysfs\n");
643 		goto out_cache;
644 	}
645 	err = register_filesystem(&v9fs_fs_type);
646 	if (err < 0) {
647 		pr_err("Failed to register filesystem\n");
648 		goto out_sysfs_cleanup;
649 	}
650 
651 	return 0;
652 
653 out_sysfs_cleanup:
654 	v9fs_sysfs_cleanup();
655 
656 out_cache:
657 	v9fs_cache_unregister();
658 
659 	return err;
660 }
661 
662 /**
663  * exit_v9fs - shutdown module
664  *
665  */
666 
667 static void __exit exit_v9fs(void)
668 {
669 	v9fs_sysfs_cleanup();
670 	v9fs_cache_unregister();
671 	unregister_filesystem(&v9fs_fs_type);
672 }
673 
674 module_init(init_v9fs)
675 module_exit(exit_v9fs)
676 
677 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
678 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
679 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
680 MODULE_LICENSE("GPL");
681