xref: /linux/fs/9p/v9fs.c (revision 95e9fd10f06cb5642028b6b851e32b8c8afb4571) 
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 			match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
188 			break;
189 		case Opt_remotename:
190 			match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
191 			break;
192 		case Opt_nodevmap:
193 			v9ses->nodev = 1;
194 			break;
195 		case Opt_cache_loose:
196 			v9ses->cache = CACHE_LOOSE;
197 			break;
198 		case Opt_fscache:
199 			v9ses->cache = CACHE_FSCACHE;
200 			break;
201 		case Opt_cachetag:
202 #ifdef CONFIG_9P_FSCACHE
203 			v9ses->cachetag = match_strdup(&args[0]);
204 #endif
205 			break;
206 		case Opt_cache:
207 			s = match_strdup(&args[0]);
208 			if (!s) {
209 				ret = -ENOMEM;
210 				p9_debug(P9_DEBUG_ERROR,
211 					 "problem allocating copy of cache arg\n");
212 				goto free_and_return;
213 			}
214 			ret = get_cache_mode(s);
215 			if (ret == -EINVAL) {
216 				kfree(s);
217 				goto free_and_return;
218 			}
219 
220 			v9ses->cache = ret;
221 			kfree(s);
222 			break;
223 
224 		case Opt_access:
225 			s = match_strdup(&args[0]);
226 			if (!s) {
227 				ret = -ENOMEM;
228 				p9_debug(P9_DEBUG_ERROR,
229 					 "problem allocating copy of access arg\n");
230 				goto free_and_return;
231 			}
232 
233 			v9ses->flags &= ~V9FS_ACCESS_MASK;
234 			if (strcmp(s, "user") == 0)
235 				v9ses->flags |= V9FS_ACCESS_USER;
236 			else if (strcmp(s, "any") == 0)
237 				v9ses->flags |= V9FS_ACCESS_ANY;
238 			else if (strcmp(s, "client") == 0) {
239 				v9ses->flags |= V9FS_ACCESS_CLIENT;
240 			} else {
241 				v9ses->flags |= V9FS_ACCESS_SINGLE;
242 				v9ses->uid = simple_strtoul(s, &e, 10);
243 				if (*e != '\0') {
244 					ret = -EINVAL;
245 					pr_info("Unknown access argument %s\n",
246 						s);
247 					kfree(s);
248 					goto free_and_return;
249 				}
250 			}
251 
252 			kfree(s);
253 			break;
254 
255 		case Opt_posixacl:
256 #ifdef CONFIG_9P_FS_POSIX_ACL
257 			v9ses->flags |= V9FS_POSIX_ACL;
258 #else
259 			p9_debug(P9_DEBUG_ERROR,
260 				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
261 #endif
262 			break;
263 
264 		default:
265 			continue;
266 		}
267 	}
268 
269 free_and_return:
270 	kfree(tmp_options);
271 fail_option_alloc:
272 	return ret;
273 }
274 
275 /**
276  * v9fs_session_init - initialize session
277  * @v9ses: session information structure
278  * @dev_name: device being mounted
279  * @data: options
280  *
281  */
282 
283 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
284 		  const char *dev_name, char *data)
285 {
286 	int retval = -EINVAL;
287 	struct p9_fid *fid;
288 	int rc;
289 
290 	v9ses->uname = __getname();
291 	if (!v9ses->uname)
292 		return ERR_PTR(-ENOMEM);
293 
294 	v9ses->aname = __getname();
295 	if (!v9ses->aname) {
296 		__putname(v9ses->uname);
297 		return ERR_PTR(-ENOMEM);
298 	}
299 	init_rwsem(&v9ses->rename_sem);
300 
301 	rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
302 	if (rc) {
303 		__putname(v9ses->aname);
304 		__putname(v9ses->uname);
305 		return ERR_PTR(rc);
306 	}
307 
308 	spin_lock(&v9fs_sessionlist_lock);
309 	list_add(&v9ses->slist, &v9fs_sessionlist);
310 	spin_unlock(&v9fs_sessionlist_lock);
311 
312 	strcpy(v9ses->uname, V9FS_DEFUSER);
313 	strcpy(v9ses->aname, V9FS_DEFANAME);
314 	v9ses->uid = ~0;
315 	v9ses->dfltuid = V9FS_DEFUID;
316 	v9ses->dfltgid = V9FS_DEFGID;
317 
318 	v9ses->clnt = p9_client_create(dev_name, data);
319 	if (IS_ERR(v9ses->clnt)) {
320 		retval = PTR_ERR(v9ses->clnt);
321 		v9ses->clnt = NULL;
322 		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
323 		goto error;
324 	}
325 
326 	v9ses->flags = V9FS_ACCESS_USER;
327 
328 	if (p9_is_proto_dotl(v9ses->clnt)) {
329 		v9ses->flags = V9FS_ACCESS_CLIENT;
330 		v9ses->flags |= V9FS_PROTO_2000L;
331 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
332 		v9ses->flags |= V9FS_PROTO_2000U;
333 	}
334 
335 	rc = v9fs_parse_options(v9ses, data);
336 	if (rc < 0) {
337 		retval = rc;
338 		goto error;
339 	}
340 
341 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
342 
343 	if (!v9fs_proto_dotl(v9ses) &&
344 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
345 		/*
346 		 * We support ACCESS_CLIENT only for dotl.
347 		 * Fall back to ACCESS_USER
348 		 */
349 		v9ses->flags &= ~V9FS_ACCESS_MASK;
350 		v9ses->flags |= V9FS_ACCESS_USER;
351 	}
352 	/*FIXME !! */
353 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
354 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
355 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
356 
357 		v9ses->flags &= ~V9FS_ACCESS_MASK;
358 		v9ses->flags |= V9FS_ACCESS_ANY;
359 		v9ses->uid = ~0;
360 	}
361 	if (!v9fs_proto_dotl(v9ses) ||
362 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
363 		/*
364 		 * We support ACL checks on clinet only if the protocol is
365 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
366 		 */
367 		v9ses->flags &= ~V9FS_ACL_MASK;
368 	}
369 
370 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
371 							v9ses->aname);
372 	if (IS_ERR(fid)) {
373 		retval = PTR_ERR(fid);
374 		fid = NULL;
375 		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
376 		goto error;
377 	}
378 
379 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
380 		fid->uid = v9ses->uid;
381 	else
382 		fid->uid = ~0;
383 
384 #ifdef CONFIG_9P_FSCACHE
385 	/* register the session for caching */
386 	v9fs_cache_session_get_cookie(v9ses);
387 #endif
388 
389 	return fid;
390 
391 error:
392 	bdi_destroy(&v9ses->bdi);
393 	return ERR_PTR(retval);
394 }
395 
396 /**
397  * v9fs_session_close - shutdown a session
398  * @v9ses: session information structure
399  *
400  */
401 
402 void v9fs_session_close(struct v9fs_session_info *v9ses)
403 {
404 	if (v9ses->clnt) {
405 		p9_client_destroy(v9ses->clnt);
406 		v9ses->clnt = NULL;
407 	}
408 
409 #ifdef CONFIG_9P_FSCACHE
410 	if (v9ses->fscache) {
411 		v9fs_cache_session_put_cookie(v9ses);
412 		kfree(v9ses->cachetag);
413 	}
414 #endif
415 	__putname(v9ses->uname);
416 	__putname(v9ses->aname);
417 
418 	bdi_destroy(&v9ses->bdi);
419 
420 	spin_lock(&v9fs_sessionlist_lock);
421 	list_del(&v9ses->slist);
422 	spin_unlock(&v9fs_sessionlist_lock);
423 }
424 
425 /**
426  * v9fs_session_cancel - terminate a session
427  * @v9ses: session to terminate
428  *
429  * mark transport as disconnected and cancel all pending requests.
430  */
431 
432 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
433 	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
434 	p9_client_disconnect(v9ses->clnt);
435 }
436 
437 /**
438  * v9fs_session_begin_cancel - Begin terminate of a session
439  * @v9ses: session to terminate
440  *
441  * After this call we don't allow any request other than clunk.
442  */
443 
444 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
445 {
446 	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
447 	p9_client_begin_disconnect(v9ses->clnt);
448 }
449 
450 extern int v9fs_error_init(void);
451 
452 static struct kobject *v9fs_kobj;
453 
454 #ifdef CONFIG_9P_FSCACHE
455 /**
456  * caches_show - list caches associated with a session
457  *
458  * Returns the size of buffer written.
459  */
460 
461 static ssize_t caches_show(struct kobject *kobj,
462 			   struct kobj_attribute *attr,
463 			   char *buf)
464 {
465 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
466 	struct v9fs_session_info *v9ses;
467 
468 	spin_lock(&v9fs_sessionlist_lock);
469 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
470 		if (v9ses->cachetag) {
471 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
472 			if (n < 0) {
473 				count = n;
474 				break;
475 			}
476 
477 			count += n;
478 			limit -= n;
479 		}
480 	}
481 
482 	spin_unlock(&v9fs_sessionlist_lock);
483 	return count;
484 }
485 
486 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
487 #endif /* CONFIG_9P_FSCACHE */
488 
489 static struct attribute *v9fs_attrs[] = {
490 #ifdef CONFIG_9P_FSCACHE
491 	&v9fs_attr_cache.attr,
492 #endif
493 	NULL,
494 };
495 
496 static struct attribute_group v9fs_attr_group = {
497 	.attrs = v9fs_attrs,
498 };
499 
500 /**
501  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
502  *
503  */
504 
505 static int v9fs_sysfs_init(void)
506 {
507 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
508 	if (!v9fs_kobj)
509 		return -ENOMEM;
510 
511 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
512 		kobject_put(v9fs_kobj);
513 		return -ENOMEM;
514 	}
515 
516 	return 0;
517 }
518 
519 /**
520  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
521  *
522  */
523 
524 static void v9fs_sysfs_cleanup(void)
525 {
526 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
527 	kobject_put(v9fs_kobj);
528 }
529 
530 static void v9fs_inode_init_once(void *foo)
531 {
532 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
533 #ifdef CONFIG_9P_FSCACHE
534 	v9inode->fscache = NULL;
535 #endif
536 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
537 	inode_init_once(&v9inode->vfs_inode);
538 }
539 
540 /**
541  * v9fs_init_inode_cache - initialize a cache for 9P
542  * Returns 0 on success.
543  */
544 static int v9fs_init_inode_cache(void)
545 {
546 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
547 					  sizeof(struct v9fs_inode),
548 					  0, (SLAB_RECLAIM_ACCOUNT|
549 					      SLAB_MEM_SPREAD),
550 					  v9fs_inode_init_once);
551 	if (!v9fs_inode_cache)
552 		return -ENOMEM;
553 
554 	return 0;
555 }
556 
557 /**
558  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
559  *
560  */
561 static void v9fs_destroy_inode_cache(void)
562 {
563 	kmem_cache_destroy(v9fs_inode_cache);
564 }
565 
566 static int v9fs_cache_register(void)
567 {
568 	int ret;
569 	ret = v9fs_init_inode_cache();
570 	if (ret < 0)
571 		return ret;
572 #ifdef CONFIG_9P_FSCACHE
573 	return fscache_register_netfs(&v9fs_cache_netfs);
574 #else
575 	return ret;
576 #endif
577 }
578 
579 static void v9fs_cache_unregister(void)
580 {
581 	v9fs_destroy_inode_cache();
582 #ifdef CONFIG_9P_FSCACHE
583 	fscache_unregister_netfs(&v9fs_cache_netfs);
584 #endif
585 }
586 
587 /**
588  * init_v9fs - Initialize module
589  *
590  */
591 
592 static int __init init_v9fs(void)
593 {
594 	int err;
595 	pr_info("Installing v9fs 9p2000 file system support\n");
596 	/* TODO: Setup list of registered trasnport modules */
597 
598 	err = v9fs_cache_register();
599 	if (err < 0) {
600 		pr_err("Failed to register v9fs for caching\n");
601 		return err;
602 	}
603 
604 	err = v9fs_sysfs_init();
605 	if (err < 0) {
606 		pr_err("Failed to register with sysfs\n");
607 		goto out_cache;
608 	}
609 	err = register_filesystem(&v9fs_fs_type);
610 	if (err < 0) {
611 		pr_err("Failed to register filesystem\n");
612 		goto out_sysfs_cleanup;
613 	}
614 
615 	return 0;
616 
617 out_sysfs_cleanup:
618 	v9fs_sysfs_cleanup();
619 
620 out_cache:
621 	v9fs_cache_unregister();
622 
623 	return err;
624 }
625 
626 /**
627  * exit_v9fs - shutdown module
628  *
629  */
630 
631 static void __exit exit_v9fs(void)
632 {
633 	v9fs_sysfs_cleanup();
634 	v9fs_cache_unregister();
635 	unregister_filesystem(&v9fs_fs_type);
636 }
637 
638 module_init(init_v9fs)
639 module_exit(exit_v9fs)
640 
641 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
642 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
643 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
644 MODULE_LICENSE("GPL");
645