xref: /openbmc/linux/fs/9p/v9fs.c (revision f7d84fa7) 
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 	v9ses->uid = INVALID_UID;
337 	v9ses->dfltuid = V9FS_DEFUID;
338 	v9ses->dfltgid = V9FS_DEFGID;
339 
340 	v9ses->clnt = p9_client_create(dev_name, data);
341 	if (IS_ERR(v9ses->clnt)) {
342 		rc = PTR_ERR(v9ses->clnt);
343 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
344 		goto err_names;
345 	}
346 
347 	v9ses->flags = V9FS_ACCESS_USER;
348 
349 	if (p9_is_proto_dotl(v9ses->clnt)) {
350 		v9ses->flags = V9FS_ACCESS_CLIENT;
351 		v9ses->flags |= V9FS_PROTO_2000L;
352 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
353 		v9ses->flags |= V9FS_PROTO_2000U;
354 	}
355 
356 	rc = v9fs_parse_options(v9ses, data);
357 	if (rc < 0)
358 		goto err_clnt;
359 
360 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
361 
362 	if (!v9fs_proto_dotl(v9ses) &&
363 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
364 		/*
365 		 * We support ACCESS_CLIENT only for dotl.
366 		 * Fall back to ACCESS_USER
367 		 */
368 		v9ses->flags &= ~V9FS_ACCESS_MASK;
369 		v9ses->flags |= V9FS_ACCESS_USER;
370 	}
371 	/*FIXME !! */
372 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
373 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
374 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
375 
376 		v9ses->flags &= ~V9FS_ACCESS_MASK;
377 		v9ses->flags |= V9FS_ACCESS_ANY;
378 		v9ses->uid = INVALID_UID;
379 	}
380 	if (!v9fs_proto_dotl(v9ses) ||
381 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
382 		/*
383 		 * We support ACL checks on clinet only if the protocol is
384 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
385 		 */
386 		v9ses->flags &= ~V9FS_ACL_MASK;
387 	}
388 
389 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
390 							v9ses->aname);
391 	if (IS_ERR(fid)) {
392 		rc = PTR_ERR(fid);
393 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
394 		goto err_clnt;
395 	}
396 
397 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
398 		fid->uid = v9ses->uid;
399 	else
400 		fid->uid = INVALID_UID;
401 
402 #ifdef CONFIG_9P_FSCACHE
403 	/* register the session for caching */
404 	v9fs_cache_session_get_cookie(v9ses);
405 #endif
406 	spin_lock(&v9fs_sessionlist_lock);
407 	list_add(&v9ses->slist, &v9fs_sessionlist);
408 	spin_unlock(&v9fs_sessionlist_lock);
409 
410 	return fid;
411 
412 err_clnt:
413 	p9_client_destroy(v9ses->clnt);
414 err_names:
415 	kfree(v9ses->uname);
416 	kfree(v9ses->aname);
417 	return ERR_PTR(rc);
418 }
419 
420 /**
421  * v9fs_session_close - shutdown a session
422  * @v9ses: session information structure
423  *
424  */
425 
426 void v9fs_session_close(struct v9fs_session_info *v9ses)
427 {
428 	if (v9ses->clnt) {
429 		p9_client_destroy(v9ses->clnt);
430 		v9ses->clnt = NULL;
431 	}
432 
433 #ifdef CONFIG_9P_FSCACHE
434 	if (v9ses->fscache) {
435 		v9fs_cache_session_put_cookie(v9ses);
436 		kfree(v9ses->cachetag);
437 	}
438 #endif
439 	kfree(v9ses->uname);
440 	kfree(v9ses->aname);
441 
442 	spin_lock(&v9fs_sessionlist_lock);
443 	list_del(&v9ses->slist);
444 	spin_unlock(&v9fs_sessionlist_lock);
445 }
446 
447 /**
448  * v9fs_session_cancel - terminate a session
449  * @v9ses: session to terminate
450  *
451  * mark transport as disconnected and cancel all pending requests.
452  */
453 
454 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
455 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
456 	p9_client_disconnect(v9ses->clnt);
457 }
458 
459 /**
460  * v9fs_session_begin_cancel - Begin terminate of a session
461  * @v9ses: session to terminate
462  *
463  * After this call we don't allow any request other than clunk.
464  */
465 
466 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
467 {
468 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
469 	p9_client_begin_disconnect(v9ses->clnt);
470 }
471 
472 extern int v9fs_error_init(void);
473 
474 static struct kobject *v9fs_kobj;
475 
476 #ifdef CONFIG_9P_FSCACHE
477 /**
478  * caches_show - list caches associated with a session
479  *
480  * Returns the size of buffer written.
481  */
482 
483 static ssize_t caches_show(struct kobject *kobj,
484 			   struct kobj_attribute *attr,
485 			   char *buf)
486 {
487 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
488 	struct v9fs_session_info *v9ses;
489 
490 	spin_lock(&v9fs_sessionlist_lock);
491 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
492 		if (v9ses->cachetag) {
493 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
494 			if (n < 0) {
495 				count = n;
496 				break;
497 			}
498 
499 			count += n;
500 			limit -= n;
501 		}
502 	}
503 
504 	spin_unlock(&v9fs_sessionlist_lock);
505 	return count;
506 }
507 
508 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
509 #endif /* CONFIG_9P_FSCACHE */
510 
511 static struct attribute *v9fs_attrs[] = {
512 #ifdef CONFIG_9P_FSCACHE
513 	&v9fs_attr_cache.attr,
514 #endif
515 	NULL,
516 };
517 
518 static struct attribute_group v9fs_attr_group = {
519 	.attrs = v9fs_attrs,
520 };
521 
522 /**
523  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
524  *
525  */
526 
527 static int __init v9fs_sysfs_init(void)
528 {
529 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
530 	if (!v9fs_kobj)
531 		return -ENOMEM;
532 
533 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
534 		kobject_put(v9fs_kobj);
535 		return -ENOMEM;
536 	}
537 
538 	return 0;
539 }
540 
541 /**
542  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
543  *
544  */
545 
546 static void v9fs_sysfs_cleanup(void)
547 {
548 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
549 	kobject_put(v9fs_kobj);
550 }
551 
552 static void v9fs_inode_init_once(void *foo)
553 {
554 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
555 #ifdef CONFIG_9P_FSCACHE
556 	v9inode->fscache = NULL;
557 #endif
558 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
559 	inode_init_once(&v9inode->vfs_inode);
560 }
561 
562 /**
563  * v9fs_init_inode_cache - initialize a cache for 9P
564  * Returns 0 on success.
565  */
566 static int v9fs_init_inode_cache(void)
567 {
568 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
569 					  sizeof(struct v9fs_inode),
570 					  0, (SLAB_RECLAIM_ACCOUNT|
571 					      SLAB_MEM_SPREAD|SLAB_ACCOUNT),
572 					  v9fs_inode_init_once);
573 	if (!v9fs_inode_cache)
574 		return -ENOMEM;
575 
576 	return 0;
577 }
578 
579 /**
580  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
581  *
582  */
583 static void v9fs_destroy_inode_cache(void)
584 {
585 	/*
586 	 * Make sure all delayed rcu free inodes are flushed before we
587 	 * destroy cache.
588 	 */
589 	rcu_barrier();
590 	kmem_cache_destroy(v9fs_inode_cache);
591 }
592 
593 static int v9fs_cache_register(void)
594 {
595 	int ret;
596 	ret = v9fs_init_inode_cache();
597 	if (ret < 0)
598 		return ret;
599 #ifdef CONFIG_9P_FSCACHE
600 	ret = fscache_register_netfs(&v9fs_cache_netfs);
601 	if (ret < 0)
602 		v9fs_destroy_inode_cache();
603 #endif
604 	return ret;
605 }
606 
607 static void v9fs_cache_unregister(void)
608 {
609 	v9fs_destroy_inode_cache();
610 #ifdef CONFIG_9P_FSCACHE
611 	fscache_unregister_netfs(&v9fs_cache_netfs);
612 #endif
613 }
614 
615 /**
616  * init_v9fs - Initialize module
617  *
618  */
619 
620 static int __init init_v9fs(void)
621 {
622 	int err;
623 	pr_info("Installing v9fs 9p2000 file system support\n");
624 	/* TODO: Setup list of registered trasnport modules */
625 
626 	err = v9fs_cache_register();
627 	if (err < 0) {
628 		pr_err("Failed to register v9fs for caching\n");
629 		return err;
630 	}
631 
632 	err = v9fs_sysfs_init();
633 	if (err < 0) {
634 		pr_err("Failed to register with sysfs\n");
635 		goto out_cache;
636 	}
637 	err = register_filesystem(&v9fs_fs_type);
638 	if (err < 0) {
639 		pr_err("Failed to register filesystem\n");
640 		goto out_sysfs_cleanup;
641 	}
642 
643 	return 0;
644 
645 out_sysfs_cleanup:
646 	v9fs_sysfs_cleanup();
647 
648 out_cache:
649 	v9fs_cache_unregister();
650 
651 	return err;
652 }
653 
654 /**
655  * exit_v9fs - shutdown module
656  *
657  */
658 
659 static void __exit exit_v9fs(void)
660 {
661 	v9fs_sysfs_cleanup();
662 	v9fs_cache_unregister();
663 	unregister_filesystem(&v9fs_fs_type);
664 }
665 
666 module_init(init_v9fs)
667 module_exit(exit_v9fs)
668 
669 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
670 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
671 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
672 MODULE_LICENSE("GPL");
673