xref: /openbmc/linux/fs/9p/v9fs.c (revision bc5aa3a0) 
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_cache, Opt_cachetag,
56 	/* Options that take no arguments */
57 	Opt_nodevmap,
58 	/* Cache options */
59 	Opt_cache_loose, Opt_fscache, Opt_mmap,
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_mmap, "mmap"},
78 	{Opt_cachetag, "cachetag=%s"},
79 	{Opt_access, "access=%s"},
80 	{Opt_posixacl, "posixacl"},
81 	{Opt_err, NULL}
82 };
83 
84 /* Interpret mount options for cache mode */
85 static int get_cache_mode(char *s)
86 {
87 	int version = -EINVAL;
88 
89 	if (!strcmp(s, "loose")) {
90 		version = CACHE_LOOSE;
91 		p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
92 	} else if (!strcmp(s, "fscache")) {
93 		version = CACHE_FSCACHE;
94 		p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
95 	} else if (!strcmp(s, "mmap")) {
96 		version = CACHE_MMAP;
97 		p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
98 	} else if (!strcmp(s, "none")) {
99 		version = CACHE_NONE;
100 		p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
101 	} else
102 		pr_info("Unknown Cache mode %s\n", s);
103 	return version;
104 }
105 
106 /**
107  * v9fs_parse_options - parse mount options into session structure
108  * @v9ses: existing v9fs session information
109  *
110  * Return 0 upon success, -ERRNO upon failure.
111  */
112 
113 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
114 {
115 	char *options, *tmp_options;
116 	substring_t args[MAX_OPT_ARGS];
117 	char *p;
118 	int option = 0;
119 	char *s, *e;
120 	int ret = 0;
121 
122 	/* setup defaults */
123 	v9ses->afid = ~0;
124 	v9ses->debug = 0;
125 	v9ses->cache = CACHE_NONE;
126 #ifdef CONFIG_9P_FSCACHE
127 	v9ses->cachetag = NULL;
128 #endif
129 
130 	if (!opts)
131 		return 0;
132 
133 	tmp_options = kstrdup(opts, GFP_KERNEL);
134 	if (!tmp_options) {
135 		ret = -ENOMEM;
136 		goto fail_option_alloc;
137 	}
138 	options = tmp_options;
139 
140 	while ((p = strsep(&options, ",")) != NULL) {
141 		int token, r;
142 		if (!*p)
143 			continue;
144 		token = match_token(p, tokens, args);
145 		switch (token) {
146 		case Opt_debug:
147 			r = match_int(&args[0], &option);
148 			if (r < 0) {
149 				p9_debug(P9_DEBUG_ERROR,
150 					 "integer field, but no integer?\n");
151 				ret = r;
152 				continue;
153 			}
154 			v9ses->debug = option;
155 #ifdef CONFIG_NET_9P_DEBUG
156 			p9_debug_level = option;
157 #endif
158 			break;
159 
160 		case Opt_dfltuid:
161 			r = match_int(&args[0], &option);
162 			if (r < 0) {
163 				p9_debug(P9_DEBUG_ERROR,
164 					 "integer field, but no integer?\n");
165 				ret = r;
166 				continue;
167 			}
168 			v9ses->dfltuid = make_kuid(current_user_ns(), option);
169 			if (!uid_valid(v9ses->dfltuid)) {
170 				p9_debug(P9_DEBUG_ERROR,
171 					 "uid field, but not a uid?\n");
172 				ret = -EINVAL;
173 				continue;
174 			}
175 			break;
176 		case Opt_dfltgid:
177 			r = match_int(&args[0], &option);
178 			if (r < 0) {
179 				p9_debug(P9_DEBUG_ERROR,
180 					 "integer field, but no integer?\n");
181 				ret = r;
182 				continue;
183 			}
184 			v9ses->dfltgid = make_kgid(current_user_ns(), option);
185 			if (!gid_valid(v9ses->dfltgid)) {
186 				p9_debug(P9_DEBUG_ERROR,
187 					 "gid field, but not a gid?\n");
188 				ret = -EINVAL;
189 				continue;
190 			}
191 			break;
192 		case Opt_afid:
193 			r = match_int(&args[0], &option);
194 			if (r < 0) {
195 				p9_debug(P9_DEBUG_ERROR,
196 					 "integer field, but no integer?\n");
197 				ret = r;
198 				continue;
199 			}
200 			v9ses->afid = option;
201 			break;
202 		case Opt_uname:
203 			kfree(v9ses->uname);
204 			v9ses->uname = match_strdup(&args[0]);
205 			if (!v9ses->uname) {
206 				ret = -ENOMEM;
207 				goto free_and_return;
208 			}
209 			break;
210 		case Opt_remotename:
211 			kfree(v9ses->aname);
212 			v9ses->aname = match_strdup(&args[0]);
213 			if (!v9ses->aname) {
214 				ret = -ENOMEM;
215 				goto free_and_return;
216 			}
217 			break;
218 		case Opt_nodevmap:
219 			v9ses->nodev = 1;
220 			break;
221 		case Opt_cache_loose:
222 			v9ses->cache = CACHE_LOOSE;
223 			break;
224 		case Opt_fscache:
225 			v9ses->cache = CACHE_FSCACHE;
226 			break;
227 		case Opt_mmap:
228 			v9ses->cache = CACHE_MMAP;
229 			break;
230 		case Opt_cachetag:
231 #ifdef CONFIG_9P_FSCACHE
232 			v9ses->cachetag = match_strdup(&args[0]);
233 #endif
234 			break;
235 		case Opt_cache:
236 			s = match_strdup(&args[0]);
237 			if (!s) {
238 				ret = -ENOMEM;
239 				p9_debug(P9_DEBUG_ERROR,
240 					 "problem allocating copy of cache arg\n");
241 				goto free_and_return;
242 			}
243 			ret = get_cache_mode(s);
244 			if (ret == -EINVAL) {
245 				kfree(s);
246 				goto free_and_return;
247 			}
248 
249 			v9ses->cache = ret;
250 			kfree(s);
251 			break;
252 
253 		case Opt_access:
254 			s = match_strdup(&args[0]);
255 			if (!s) {
256 				ret = -ENOMEM;
257 				p9_debug(P9_DEBUG_ERROR,
258 					 "problem allocating copy of access arg\n");
259 				goto free_and_return;
260 			}
261 
262 			v9ses->flags &= ~V9FS_ACCESS_MASK;
263 			if (strcmp(s, "user") == 0)
264 				v9ses->flags |= V9FS_ACCESS_USER;
265 			else if (strcmp(s, "any") == 0)
266 				v9ses->flags |= V9FS_ACCESS_ANY;
267 			else if (strcmp(s, "client") == 0) {
268 				v9ses->flags |= V9FS_ACCESS_CLIENT;
269 			} else {
270 				uid_t uid;
271 				v9ses->flags |= V9FS_ACCESS_SINGLE;
272 				uid = simple_strtoul(s, &e, 10);
273 				if (*e != '\0') {
274 					ret = -EINVAL;
275 					pr_info("Unknown access argument %s\n",
276 						s);
277 					kfree(s);
278 					goto free_and_return;
279 				}
280 				v9ses->uid = make_kuid(current_user_ns(), uid);
281 				if (!uid_valid(v9ses->uid)) {
282 					ret = -EINVAL;
283 					pr_info("Uknown uid %s\n", s);
284 					kfree(s);
285 					goto free_and_return;
286 				}
287 			}
288 
289 			kfree(s);
290 			break;
291 
292 		case Opt_posixacl:
293 #ifdef CONFIG_9P_FS_POSIX_ACL
294 			v9ses->flags |= V9FS_POSIX_ACL;
295 #else
296 			p9_debug(P9_DEBUG_ERROR,
297 				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
298 #endif
299 			break;
300 
301 		default:
302 			continue;
303 		}
304 	}
305 
306 free_and_return:
307 	kfree(tmp_options);
308 fail_option_alloc:
309 	return ret;
310 }
311 
312 /**
313  * v9fs_session_init - initialize session
314  * @v9ses: session information structure
315  * @dev_name: device being mounted
316  * @data: options
317  *
318  */
319 
320 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
321 		  const char *dev_name, char *data)
322 {
323 	struct p9_fid *fid;
324 	int rc = -ENOMEM;
325 
326 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
327 	if (!v9ses->uname)
328 		goto err_names;
329 
330 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
331 	if (!v9ses->aname)
332 		goto err_names;
333 	init_rwsem(&v9ses->rename_sem);
334 
335 	rc = bdi_setup_and_register(&v9ses->bdi, "9p");
336 	if (rc)
337 		goto err_names;
338 
339 	v9ses->uid = INVALID_UID;
340 	v9ses->dfltuid = V9FS_DEFUID;
341 	v9ses->dfltgid = V9FS_DEFGID;
342 
343 	v9ses->clnt = p9_client_create(dev_name, data);
344 	if (IS_ERR(v9ses->clnt)) {
345 		rc = PTR_ERR(v9ses->clnt);
346 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
347 		goto err_bdi;
348 	}
349 
350 	v9ses->flags = V9FS_ACCESS_USER;
351 
352 	if (p9_is_proto_dotl(v9ses->clnt)) {
353 		v9ses->flags = V9FS_ACCESS_CLIENT;
354 		v9ses->flags |= V9FS_PROTO_2000L;
355 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
356 		v9ses->flags |= V9FS_PROTO_2000U;
357 	}
358 
359 	rc = v9fs_parse_options(v9ses, data);
360 	if (rc < 0)
361 		goto err_clnt;
362 
363 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
364 
365 	if (!v9fs_proto_dotl(v9ses) &&
366 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
367 		/*
368 		 * We support ACCESS_CLIENT only for dotl.
369 		 * Fall back to ACCESS_USER
370 		 */
371 		v9ses->flags &= ~V9FS_ACCESS_MASK;
372 		v9ses->flags |= V9FS_ACCESS_USER;
373 	}
374 	/*FIXME !! */
375 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
376 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
377 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
378 
379 		v9ses->flags &= ~V9FS_ACCESS_MASK;
380 		v9ses->flags |= V9FS_ACCESS_ANY;
381 		v9ses->uid = INVALID_UID;
382 	}
383 	if (!v9fs_proto_dotl(v9ses) ||
384 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
385 		/*
386 		 * We support ACL checks on clinet only if the protocol is
387 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
388 		 */
389 		v9ses->flags &= ~V9FS_ACL_MASK;
390 	}
391 
392 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
393 							v9ses->aname);
394 	if (IS_ERR(fid)) {
395 		rc = PTR_ERR(fid);
396 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
397 		goto err_clnt;
398 	}
399 
400 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
401 		fid->uid = v9ses->uid;
402 	else
403 		fid->uid = INVALID_UID;
404 
405 #ifdef CONFIG_9P_FSCACHE
406 	/* register the session for caching */
407 	v9fs_cache_session_get_cookie(v9ses);
408 #endif
409 	spin_lock(&v9fs_sessionlist_lock);
410 	list_add(&v9ses->slist, &v9fs_sessionlist);
411 	spin_unlock(&v9fs_sessionlist_lock);
412 
413 	return fid;
414 
415 err_clnt:
416 	p9_client_destroy(v9ses->clnt);
417 err_bdi:
418 	bdi_destroy(&v9ses->bdi);
419 err_names:
420 	kfree(v9ses->uname);
421 	kfree(v9ses->aname);
422 	return ERR_PTR(rc);
423 }
424 
425 /**
426  * v9fs_session_close - shutdown a session
427  * @v9ses: session information structure
428  *
429  */
430 
431 void v9fs_session_close(struct v9fs_session_info *v9ses)
432 {
433 	if (v9ses->clnt) {
434 		p9_client_destroy(v9ses->clnt);
435 		v9ses->clnt = NULL;
436 	}
437 
438 #ifdef CONFIG_9P_FSCACHE
439 	if (v9ses->fscache) {
440 		v9fs_cache_session_put_cookie(v9ses);
441 		kfree(v9ses->cachetag);
442 	}
443 #endif
444 	kfree(v9ses->uname);
445 	kfree(v9ses->aname);
446 
447 	bdi_destroy(&v9ses->bdi);
448 
449 	spin_lock(&v9fs_sessionlist_lock);
450 	list_del(&v9ses->slist);
451 	spin_unlock(&v9fs_sessionlist_lock);
452 }
453 
454 /**
455  * v9fs_session_cancel - terminate a session
456  * @v9ses: session to terminate
457  *
458  * mark transport as disconnected and cancel all pending requests.
459  */
460 
461 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
462 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
463 	p9_client_disconnect(v9ses->clnt);
464 }
465 
466 /**
467  * v9fs_session_begin_cancel - Begin terminate of a session
468  * @v9ses: session to terminate
469  *
470  * After this call we don't allow any request other than clunk.
471  */
472 
473 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
474 {
475 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
476 	p9_client_begin_disconnect(v9ses->clnt);
477 }
478 
479 extern int v9fs_error_init(void);
480 
481 static struct kobject *v9fs_kobj;
482 
483 #ifdef CONFIG_9P_FSCACHE
484 /**
485  * caches_show - list caches associated with a session
486  *
487  * Returns the size of buffer written.
488  */
489 
490 static ssize_t caches_show(struct kobject *kobj,
491 			   struct kobj_attribute *attr,
492 			   char *buf)
493 {
494 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
495 	struct v9fs_session_info *v9ses;
496 
497 	spin_lock(&v9fs_sessionlist_lock);
498 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
499 		if (v9ses->cachetag) {
500 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
501 			if (n < 0) {
502 				count = n;
503 				break;
504 			}
505 
506 			count += n;
507 			limit -= n;
508 		}
509 	}
510 
511 	spin_unlock(&v9fs_sessionlist_lock);
512 	return count;
513 }
514 
515 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
516 #endif /* CONFIG_9P_FSCACHE */
517 
518 static struct attribute *v9fs_attrs[] = {
519 #ifdef CONFIG_9P_FSCACHE
520 	&v9fs_attr_cache.attr,
521 #endif
522 	NULL,
523 };
524 
525 static struct attribute_group v9fs_attr_group = {
526 	.attrs = v9fs_attrs,
527 };
528 
529 /**
530  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
531  *
532  */
533 
534 static int __init v9fs_sysfs_init(void)
535 {
536 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
537 	if (!v9fs_kobj)
538 		return -ENOMEM;
539 
540 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
541 		kobject_put(v9fs_kobj);
542 		return -ENOMEM;
543 	}
544 
545 	return 0;
546 }
547 
548 /**
549  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
550  *
551  */
552 
553 static void v9fs_sysfs_cleanup(void)
554 {
555 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
556 	kobject_put(v9fs_kobj);
557 }
558 
559 static void v9fs_inode_init_once(void *foo)
560 {
561 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
562 #ifdef CONFIG_9P_FSCACHE
563 	v9inode->fscache = NULL;
564 #endif
565 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
566 	inode_init_once(&v9inode->vfs_inode);
567 }
568 
569 /**
570  * v9fs_init_inode_cache - initialize a cache for 9P
571  * Returns 0 on success.
572  */
573 static int v9fs_init_inode_cache(void)
574 {
575 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
576 					  sizeof(struct v9fs_inode),
577 					  0, (SLAB_RECLAIM_ACCOUNT|
578 					      SLAB_MEM_SPREAD|SLAB_ACCOUNT),
579 					  v9fs_inode_init_once);
580 	if (!v9fs_inode_cache)
581 		return -ENOMEM;
582 
583 	return 0;
584 }
585 
586 /**
587  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
588  *
589  */
590 static void v9fs_destroy_inode_cache(void)
591 {
592 	/*
593 	 * Make sure all delayed rcu free inodes are flushed before we
594 	 * destroy cache.
595 	 */
596 	rcu_barrier();
597 	kmem_cache_destroy(v9fs_inode_cache);
598 }
599 
600 static int v9fs_cache_register(void)
601 {
602 	int ret;
603 	ret = v9fs_init_inode_cache();
604 	if (ret < 0)
605 		return ret;
606 #ifdef CONFIG_9P_FSCACHE
607 	ret = fscache_register_netfs(&v9fs_cache_netfs);
608 	if (ret < 0)
609 		v9fs_destroy_inode_cache();
610 #endif
611 	return ret;
612 }
613 
614 static void v9fs_cache_unregister(void)
615 {
616 	v9fs_destroy_inode_cache();
617 #ifdef CONFIG_9P_FSCACHE
618 	fscache_unregister_netfs(&v9fs_cache_netfs);
619 #endif
620 }
621 
622 /**
623  * init_v9fs - Initialize module
624  *
625  */
626 
627 static int __init init_v9fs(void)
628 {
629 	int err;
630 	pr_info("Installing v9fs 9p2000 file system support\n");
631 	/* TODO: Setup list of registered trasnport modules */
632 
633 	err = v9fs_cache_register();
634 	if (err < 0) {
635 		pr_err("Failed to register v9fs for caching\n");
636 		return err;
637 	}
638 
639 	err = v9fs_sysfs_init();
640 	if (err < 0) {
641 		pr_err("Failed to register with sysfs\n");
642 		goto out_cache;
643 	}
644 	err = register_filesystem(&v9fs_fs_type);
645 	if (err < 0) {
646 		pr_err("Failed to register filesystem\n");
647 		goto out_sysfs_cleanup;
648 	}
649 
650 	return 0;
651 
652 out_sysfs_cleanup:
653 	v9fs_sysfs_cleanup();
654 
655 out_cache:
656 	v9fs_cache_unregister();
657 
658 	return err;
659 }
660 
661 /**
662  * exit_v9fs - shutdown module
663  *
664  */
665 
666 static void __exit exit_v9fs(void)
667 {
668 	v9fs_sysfs_cleanup();
669 	v9fs_cache_unregister();
670 	unregister_filesystem(&v9fs_fs_type);
671 }
672 
673 module_init(init_v9fs)
674 module_exit(exit_v9fs)
675 
676 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
677 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
678 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
679 MODULE_LICENSE("GPL");
680