xref: /openbmc/linux/fs/9p/v9fs.c (revision 84764a41) 
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 = option;
165 			break;
166 		case Opt_dfltgid:
167 			r = match_int(&args[0], &option);
168 			if (r < 0) {
169 				p9_debug(P9_DEBUG_ERROR,
170 					 "integer field, but no integer?\n");
171 				ret = r;
172 				continue;
173 			}
174 			v9ses->dfltgid = option;
175 			break;
176 		case Opt_afid:
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->afid = option;
185 			break;
186 		case Opt_uname:
187 			kfree(v9ses->uname);
188 			v9ses->uname = match_strdup(&args[0]);
189 			if (!v9ses->uname) {
190 				ret = -ENOMEM;
191 				goto free_and_return;
192 			}
193 			break;
194 		case Opt_remotename:
195 			kfree(v9ses->aname);
196 			v9ses->aname = match_strdup(&args[0]);
197 			if (!v9ses->aname) {
198 				ret = -ENOMEM;
199 				goto free_and_return;
200 			}
201 			break;
202 		case Opt_nodevmap:
203 			v9ses->nodev = 1;
204 			break;
205 		case Opt_cache_loose:
206 			v9ses->cache = CACHE_LOOSE;
207 			break;
208 		case Opt_fscache:
209 			v9ses->cache = CACHE_FSCACHE;
210 			break;
211 		case Opt_cachetag:
212 #ifdef CONFIG_9P_FSCACHE
213 			v9ses->cachetag = match_strdup(&args[0]);
214 #endif
215 			break;
216 		case Opt_cache:
217 			s = match_strdup(&args[0]);
218 			if (!s) {
219 				ret = -ENOMEM;
220 				p9_debug(P9_DEBUG_ERROR,
221 					 "problem allocating copy of cache arg\n");
222 				goto free_and_return;
223 			}
224 			ret = get_cache_mode(s);
225 			if (ret == -EINVAL) {
226 				kfree(s);
227 				goto free_and_return;
228 			}
229 
230 			v9ses->cache = ret;
231 			kfree(s);
232 			break;
233 
234 		case Opt_access:
235 			s = match_strdup(&args[0]);
236 			if (!s) {
237 				ret = -ENOMEM;
238 				p9_debug(P9_DEBUG_ERROR,
239 					 "problem allocating copy of access arg\n");
240 				goto free_and_return;
241 			}
242 
243 			v9ses->flags &= ~V9FS_ACCESS_MASK;
244 			if (strcmp(s, "user") == 0)
245 				v9ses->flags |= V9FS_ACCESS_USER;
246 			else if (strcmp(s, "any") == 0)
247 				v9ses->flags |= V9FS_ACCESS_ANY;
248 			else if (strcmp(s, "client") == 0) {
249 				v9ses->flags |= V9FS_ACCESS_CLIENT;
250 			} else {
251 				v9ses->flags |= V9FS_ACCESS_SINGLE;
252 				v9ses->uid = simple_strtoul(s, &e, 10);
253 				if (*e != '\0') {
254 					ret = -EINVAL;
255 					pr_info("Unknown access argument %s\n",
256 						s);
257 					kfree(s);
258 					goto free_and_return;
259 				}
260 			}
261 
262 			kfree(s);
263 			break;
264 
265 		case Opt_posixacl:
266 #ifdef CONFIG_9P_FS_POSIX_ACL
267 			v9ses->flags |= V9FS_POSIX_ACL;
268 #else
269 			p9_debug(P9_DEBUG_ERROR,
270 				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
271 #endif
272 			break;
273 
274 		default:
275 			continue;
276 		}
277 	}
278 
279 free_and_return:
280 	kfree(tmp_options);
281 fail_option_alloc:
282 	return ret;
283 }
284 
285 /**
286  * v9fs_session_init - initialize session
287  * @v9ses: session information structure
288  * @dev_name: device being mounted
289  * @data: options
290  *
291  */
292 
293 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
294 		  const char *dev_name, char *data)
295 {
296 	int retval = -EINVAL;
297 	struct p9_fid *fid;
298 	int rc;
299 
300 	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
301 	if (!v9ses->uname)
302 		return ERR_PTR(-ENOMEM);
303 
304 	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
305 	if (!v9ses->aname) {
306 		kfree(v9ses->uname);
307 		return ERR_PTR(-ENOMEM);
308 	}
309 	init_rwsem(&v9ses->rename_sem);
310 
311 	rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
312 	if (rc) {
313 		kfree(v9ses->aname);
314 		kfree(v9ses->uname);
315 		return ERR_PTR(rc);
316 	}
317 
318 	spin_lock(&v9fs_sessionlist_lock);
319 	list_add(&v9ses->slist, &v9fs_sessionlist);
320 	spin_unlock(&v9fs_sessionlist_lock);
321 
322 	v9ses->uid = ~0;
323 	v9ses->dfltuid = V9FS_DEFUID;
324 	v9ses->dfltgid = V9FS_DEFGID;
325 
326 	v9ses->clnt = p9_client_create(dev_name, data);
327 	if (IS_ERR(v9ses->clnt)) {
328 		retval = PTR_ERR(v9ses->clnt);
329 		v9ses->clnt = NULL;
330 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
331 		goto error;
332 	}
333 
334 	v9ses->flags = V9FS_ACCESS_USER;
335 
336 	if (p9_is_proto_dotl(v9ses->clnt)) {
337 		v9ses->flags = V9FS_ACCESS_CLIENT;
338 		v9ses->flags |= V9FS_PROTO_2000L;
339 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
340 		v9ses->flags |= V9FS_PROTO_2000U;
341 	}
342 
343 	rc = v9fs_parse_options(v9ses, data);
344 	if (rc < 0) {
345 		retval = rc;
346 		goto error;
347 	}
348 
349 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
350 
351 	if (!v9fs_proto_dotl(v9ses) &&
352 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
353 		/*
354 		 * We support ACCESS_CLIENT only for dotl.
355 		 * Fall back to ACCESS_USER
356 		 */
357 		v9ses->flags &= ~V9FS_ACCESS_MASK;
358 		v9ses->flags |= V9FS_ACCESS_USER;
359 	}
360 	/*FIXME !! */
361 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
362 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
363 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
364 
365 		v9ses->flags &= ~V9FS_ACCESS_MASK;
366 		v9ses->flags |= V9FS_ACCESS_ANY;
367 		v9ses->uid = ~0;
368 	}
369 	if (!v9fs_proto_dotl(v9ses) ||
370 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
371 		/*
372 		 * We support ACL checks on clinet only if the protocol is
373 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
374 		 */
375 		v9ses->flags &= ~V9FS_ACL_MASK;
376 	}
377 
378 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
379 							v9ses->aname);
380 	if (IS_ERR(fid)) {
381 		retval = PTR_ERR(fid);
382 		fid = NULL;
383 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
384 		goto error;
385 	}
386 
387 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
388 		fid->uid = v9ses->uid;
389 	else
390 		fid->uid = ~0;
391 
392 #ifdef CONFIG_9P_FSCACHE
393 	/* register the session for caching */
394 	v9fs_cache_session_get_cookie(v9ses);
395 #endif
396 
397 	return fid;
398 
399 error:
400 	bdi_destroy(&v9ses->bdi);
401 	return ERR_PTR(retval);
402 }
403 
404 /**
405  * v9fs_session_close - shutdown a session
406  * @v9ses: session information structure
407  *
408  */
409 
410 void v9fs_session_close(struct v9fs_session_info *v9ses)
411 {
412 	if (v9ses->clnt) {
413 		p9_client_destroy(v9ses->clnt);
414 		v9ses->clnt = NULL;
415 	}
416 
417 #ifdef CONFIG_9P_FSCACHE
418 	if (v9ses->fscache) {
419 		v9fs_cache_session_put_cookie(v9ses);
420 		kfree(v9ses->cachetag);
421 	}
422 #endif
423 	kfree(v9ses->uname);
424 	kfree(v9ses->aname);
425 
426 	bdi_destroy(&v9ses->bdi);
427 
428 	spin_lock(&v9fs_sessionlist_lock);
429 	list_del(&v9ses->slist);
430 	spin_unlock(&v9fs_sessionlist_lock);
431 }
432 
433 /**
434  * v9fs_session_cancel - terminate a session
435  * @v9ses: session to terminate
436  *
437  * mark transport as disconnected and cancel all pending requests.
438  */
439 
440 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
441 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
442 	p9_client_disconnect(v9ses->clnt);
443 }
444 
445 /**
446  * v9fs_session_begin_cancel - Begin terminate of a session
447  * @v9ses: session to terminate
448  *
449  * After this call we don't allow any request other than clunk.
450  */
451 
452 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
453 {
454 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
455 	p9_client_begin_disconnect(v9ses->clnt);
456 }
457 
458 extern int v9fs_error_init(void);
459 
460 static struct kobject *v9fs_kobj;
461 
462 #ifdef CONFIG_9P_FSCACHE
463 /**
464  * caches_show - list caches associated with a session
465  *
466  * Returns the size of buffer written.
467  */
468 
469 static ssize_t caches_show(struct kobject *kobj,
470 			   struct kobj_attribute *attr,
471 			   char *buf)
472 {
473 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
474 	struct v9fs_session_info *v9ses;
475 
476 	spin_lock(&v9fs_sessionlist_lock);
477 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
478 		if (v9ses->cachetag) {
479 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
480 			if (n < 0) {
481 				count = n;
482 				break;
483 			}
484 
485 			count += n;
486 			limit -= n;
487 		}
488 	}
489 
490 	spin_unlock(&v9fs_sessionlist_lock);
491 	return count;
492 }
493 
494 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
495 #endif /* CONFIG_9P_FSCACHE */
496 
497 static struct attribute *v9fs_attrs[] = {
498 #ifdef CONFIG_9P_FSCACHE
499 	&v9fs_attr_cache.attr,
500 #endif
501 	NULL,
502 };
503 
504 static struct attribute_group v9fs_attr_group = {
505 	.attrs = v9fs_attrs,
506 };
507 
508 /**
509  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
510  *
511  */
512 
513 static int v9fs_sysfs_init(void)
514 {
515 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
516 	if (!v9fs_kobj)
517 		return -ENOMEM;
518 
519 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
520 		kobject_put(v9fs_kobj);
521 		return -ENOMEM;
522 	}
523 
524 	return 0;
525 }
526 
527 /**
528  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
529  *
530  */
531 
532 static void v9fs_sysfs_cleanup(void)
533 {
534 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
535 	kobject_put(v9fs_kobj);
536 }
537 
538 static void v9fs_inode_init_once(void *foo)
539 {
540 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
541 #ifdef CONFIG_9P_FSCACHE
542 	v9inode->fscache = NULL;
543 #endif
544 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
545 	inode_init_once(&v9inode->vfs_inode);
546 }
547 
548 /**
549  * v9fs_init_inode_cache - initialize a cache for 9P
550  * Returns 0 on success.
551  */
552 static int v9fs_init_inode_cache(void)
553 {
554 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
555 					  sizeof(struct v9fs_inode),
556 					  0, (SLAB_RECLAIM_ACCOUNT|
557 					      SLAB_MEM_SPREAD),
558 					  v9fs_inode_init_once);
559 	if (!v9fs_inode_cache)
560 		return -ENOMEM;
561 
562 	return 0;
563 }
564 
565 /**
566  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
567  *
568  */
569 static void v9fs_destroy_inode_cache(void)
570 {
571 	/*
572 	 * Make sure all delayed rcu free inodes are flushed before we
573 	 * destroy cache.
574 	 */
575 	rcu_barrier();
576 	kmem_cache_destroy(v9fs_inode_cache);
577 }
578 
579 static int v9fs_cache_register(void)
580 {
581 	int ret;
582 	ret = v9fs_init_inode_cache();
583 	if (ret < 0)
584 		return ret;
585 #ifdef CONFIG_9P_FSCACHE
586 	return fscache_register_netfs(&v9fs_cache_netfs);
587 #else
588 	return ret;
589 #endif
590 }
591 
592 static void v9fs_cache_unregister(void)
593 {
594 	v9fs_destroy_inode_cache();
595 #ifdef CONFIG_9P_FSCACHE
596 	fscache_unregister_netfs(&v9fs_cache_netfs);
597 #endif
598 }
599 
600 /**
601  * init_v9fs - Initialize module
602  *
603  */
604 
605 static int __init init_v9fs(void)
606 {
607 	int err;
608 	pr_info("Installing v9fs 9p2000 file system support\n");
609 	/* TODO: Setup list of registered trasnport modules */
610 
611 	err = v9fs_cache_register();
612 	if (err < 0) {
613 		pr_err("Failed to register v9fs for caching\n");
614 		return err;
615 	}
616 
617 	err = v9fs_sysfs_init();
618 	if (err < 0) {
619 		pr_err("Failed to register with sysfs\n");
620 		goto out_cache;
621 	}
622 	err = register_filesystem(&v9fs_fs_type);
623 	if (err < 0) {
624 		pr_err("Failed to register filesystem\n");
625 		goto out_sysfs_cleanup;
626 	}
627 
628 	return 0;
629 
630 out_sysfs_cleanup:
631 	v9fs_sysfs_cleanup();
632 
633 out_cache:
634 	v9fs_cache_unregister();
635 
636 	return err;
637 }
638 
639 /**
640  * exit_v9fs - shutdown module
641  *
642  */
643 
644 static void __exit exit_v9fs(void)
645 {
646 	v9fs_sysfs_cleanup();
647 	v9fs_cache_unregister();
648 	unregister_filesystem(&v9fs_fs_type);
649 }
650 
651 module_init(init_v9fs)
652 module_exit(exit_v9fs)
653 
654 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
655 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
656 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
657 MODULE_LICENSE("GPL");
658