xref: /linux/fs/9p/v9fs.c (revision 60e13231561b3a4c5269bfa1ef6c0569ad6f28ec) 
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 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/fs.h>
29 #include <linux/sched.h>
30 #include <linux/parser.h>
31 #include <linux/idr.h>
32 #include <linux/slab.h>
33 #include <net/9p/9p.h>
34 #include <net/9p/client.h>
35 #include <net/9p/transport.h>
36 #include "v9fs.h"
37 #include "v9fs_vfs.h"
38 #include "cache.h"
39 
40 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
41 static LIST_HEAD(v9fs_sessionlist);
42 struct kmem_cache *v9fs_inode_cache;
43 
44 /*
45  * Option Parsing (code inspired by NFS code)
46  *  NOTE: each transport will parse its own options
47  */
48 
49 enum {
50 	/* Options that take integer arguments */
51 	Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
52 	/* String options */
53 	Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
54 	/* Options that take no arguments */
55 	Opt_nodevmap,
56 	/* Cache options */
57 	Opt_cache_loose, Opt_fscache,
58 	/* Access options */
59 	Opt_access, Opt_posixacl,
60 	/* Error token */
61 	Opt_err
62 };
63 
64 static const match_table_t tokens = {
65 	{Opt_debug, "debug=%x"},
66 	{Opt_dfltuid, "dfltuid=%u"},
67 	{Opt_dfltgid, "dfltgid=%u"},
68 	{Opt_afid, "afid=%u"},
69 	{Opt_uname, "uname=%s"},
70 	{Opt_remotename, "aname=%s"},
71 	{Opt_nodevmap, "nodevmap"},
72 	{Opt_cache, "cache=%s"},
73 	{Opt_cache_loose, "loose"},
74 	{Opt_fscache, "fscache"},
75 	{Opt_cachetag, "cachetag=%s"},
76 	{Opt_access, "access=%s"},
77 	{Opt_posixacl, "posixacl"},
78 	{Opt_err, NULL}
79 };
80 
81 /* Interpret mount options for cache mode */
82 static int get_cache_mode(char *s)
83 {
84 	int version = -EINVAL;
85 
86 	if (!strcmp(s, "loose")) {
87 		version = CACHE_LOOSE;
88 		P9_DPRINTK(P9_DEBUG_9P, "Cache mode: loose\n");
89 	} else if (!strcmp(s, "fscache")) {
90 		version = CACHE_FSCACHE;
91 		P9_DPRINTK(P9_DEBUG_9P, "Cache mode: fscache\n");
92 	} else if (!strcmp(s, "none")) {
93 		version = CACHE_NONE;
94 		P9_DPRINTK(P9_DEBUG_9P, "Cache mode: none\n");
95 	} else
96 		printk(KERN_INFO "9p: Unknown Cache mode %s.\n", s);
97 	return version;
98 }
99 
100 /**
101  * v9fs_parse_options - parse mount options into session structure
102  * @v9ses: existing v9fs session information
103  *
104  * Return 0 upon success, -ERRNO upon failure.
105  */
106 
107 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
108 {
109 	char *options, *tmp_options;
110 	substring_t args[MAX_OPT_ARGS];
111 	char *p;
112 	int option = 0;
113 	char *s, *e;
114 	int ret = 0;
115 
116 	/* setup defaults */
117 	v9ses->afid = ~0;
118 	v9ses->debug = 0;
119 	v9ses->cache = CACHE_NONE;
120 #ifdef CONFIG_9P_FSCACHE
121 	v9ses->cachetag = NULL;
122 #endif
123 
124 	if (!opts)
125 		return 0;
126 
127 	tmp_options = kstrdup(opts, GFP_KERNEL);
128 	if (!tmp_options) {
129 		ret = -ENOMEM;
130 		goto fail_option_alloc;
131 	}
132 	options = tmp_options;
133 
134 	while ((p = strsep(&options, ",")) != NULL) {
135 		int token;
136 		if (!*p)
137 			continue;
138 		token = match_token(p, tokens, args);
139 		if (token < Opt_uname) {
140 			int r = match_int(&args[0], &option);
141 			if (r < 0) {
142 				P9_DPRINTK(P9_DEBUG_ERROR,
143 					"integer field, but no integer?\n");
144 				ret = r;
145 				continue;
146 			}
147 		}
148 		switch (token) {
149 		case Opt_debug:
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 			v9ses->dfltuid = option;
158 			break;
159 		case Opt_dfltgid:
160 			v9ses->dfltgid = option;
161 			break;
162 		case Opt_afid:
163 			v9ses->afid = option;
164 			break;
165 		case Opt_uname:
166 			match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
167 			break;
168 		case Opt_remotename:
169 			match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
170 			break;
171 		case Opt_nodevmap:
172 			v9ses->nodev = 1;
173 			break;
174 		case Opt_cache_loose:
175 			v9ses->cache = CACHE_LOOSE;
176 			break;
177 		case Opt_fscache:
178 			v9ses->cache = CACHE_FSCACHE;
179 			break;
180 		case Opt_cachetag:
181 #ifdef CONFIG_9P_FSCACHE
182 			v9ses->cachetag = match_strdup(&args[0]);
183 #endif
184 			break;
185 		case Opt_cache:
186 			s = match_strdup(&args[0]);
187 			if (!s) {
188 				ret = -ENOMEM;
189 				P9_DPRINTK(P9_DEBUG_ERROR,
190 				  "problem allocating copy of cache arg\n");
191 				goto free_and_return;
192 			}
193 			ret = get_cache_mode(s);
194 			if (ret == -EINVAL) {
195 				kfree(s);
196 				goto free_and_return;
197 			}
198 
199 			v9ses->cache = ret;
200 			kfree(s);
201 			break;
202 
203 		case Opt_access:
204 			s = match_strdup(&args[0]);
205 			if (!s) {
206 				ret = -ENOMEM;
207 				P9_DPRINTK(P9_DEBUG_ERROR,
208 				  "problem allocating copy of access arg\n");
209 				goto free_and_return;
210 			}
211 
212 			v9ses->flags &= ~V9FS_ACCESS_MASK;
213 			if (strcmp(s, "user") == 0)
214 				v9ses->flags |= V9FS_ACCESS_USER;
215 			else if (strcmp(s, "any") == 0)
216 				v9ses->flags |= V9FS_ACCESS_ANY;
217 			else if (strcmp(s, "client") == 0) {
218 				v9ses->flags |= V9FS_ACCESS_CLIENT;
219 			} else {
220 				v9ses->flags |= V9FS_ACCESS_SINGLE;
221 				v9ses->uid = simple_strtoul(s, &e, 10);
222 				if (*e != '\0') {
223 					ret = -EINVAL;
224 					printk(KERN_INFO "9p: Unknown access "
225 							"argument %s.\n", s);
226 					kfree(s);
227 					goto free_and_return;
228 				}
229 			}
230 
231 			kfree(s);
232 			break;
233 
234 		case Opt_posixacl:
235 #ifdef CONFIG_9P_FS_POSIX_ACL
236 			v9ses->flags |= V9FS_POSIX_ACL;
237 #else
238 			P9_DPRINTK(P9_DEBUG_ERROR,
239 					"Not defined CONFIG_9P_FS_POSIX_ACL. "
240 					"Ignoring posixacl option\n");
241 #endif
242 			break;
243 
244 		default:
245 			continue;
246 		}
247 	}
248 
249 free_and_return:
250 	kfree(tmp_options);
251 fail_option_alloc:
252 	return ret;
253 }
254 
255 /**
256  * v9fs_session_init - initialize session
257  * @v9ses: session information structure
258  * @dev_name: device being mounted
259  * @data: options
260  *
261  */
262 
263 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
264 		  const char *dev_name, char *data)
265 {
266 	int retval = -EINVAL;
267 	struct p9_fid *fid;
268 	int rc;
269 
270 	v9ses->uname = __getname();
271 	if (!v9ses->uname)
272 		return ERR_PTR(-ENOMEM);
273 
274 	v9ses->aname = __getname();
275 	if (!v9ses->aname) {
276 		__putname(v9ses->uname);
277 		return ERR_PTR(-ENOMEM);
278 	}
279 	init_rwsem(&v9ses->rename_sem);
280 
281 	rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
282 	if (rc) {
283 		__putname(v9ses->aname);
284 		__putname(v9ses->uname);
285 		return ERR_PTR(rc);
286 	}
287 
288 	spin_lock(&v9fs_sessionlist_lock);
289 	list_add(&v9ses->slist, &v9fs_sessionlist);
290 	spin_unlock(&v9fs_sessionlist_lock);
291 
292 	strcpy(v9ses->uname, V9FS_DEFUSER);
293 	strcpy(v9ses->aname, V9FS_DEFANAME);
294 	v9ses->uid = ~0;
295 	v9ses->dfltuid = V9FS_DEFUID;
296 	v9ses->dfltgid = V9FS_DEFGID;
297 
298 	v9ses->clnt = p9_client_create(dev_name, data);
299 	if (IS_ERR(v9ses->clnt)) {
300 		retval = PTR_ERR(v9ses->clnt);
301 		v9ses->clnt = NULL;
302 		P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
303 		goto error;
304 	}
305 
306 	v9ses->flags = V9FS_ACCESS_USER;
307 
308 	if (p9_is_proto_dotl(v9ses->clnt)) {
309 		v9ses->flags = V9FS_ACCESS_CLIENT;
310 		v9ses->flags |= V9FS_PROTO_2000L;
311 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
312 		v9ses->flags |= V9FS_PROTO_2000U;
313 	}
314 
315 	rc = v9fs_parse_options(v9ses, data);
316 	if (rc < 0) {
317 		retval = rc;
318 		goto error;
319 	}
320 
321 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
322 
323 	if (!v9fs_proto_dotl(v9ses) &&
324 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
325 		/*
326 		 * We support ACCESS_CLIENT only for dotl.
327 		 * Fall back to ACCESS_USER
328 		 */
329 		v9ses->flags &= ~V9FS_ACCESS_MASK;
330 		v9ses->flags |= V9FS_ACCESS_USER;
331 	}
332 	/*FIXME !! */
333 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
334 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
335 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
336 
337 		v9ses->flags &= ~V9FS_ACCESS_MASK;
338 		v9ses->flags |= V9FS_ACCESS_ANY;
339 		v9ses->uid = ~0;
340 	}
341 	if (!v9fs_proto_dotl(v9ses) ||
342 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
343 		/*
344 		 * We support ACL checks on clinet only if the protocol is
345 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
346 		 */
347 		v9ses->flags &= ~V9FS_ACL_MASK;
348 	}
349 
350 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
351 							v9ses->aname);
352 	if (IS_ERR(fid)) {
353 		retval = PTR_ERR(fid);
354 		fid = NULL;
355 		P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
356 		goto error;
357 	}
358 
359 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
360 		fid->uid = v9ses->uid;
361 	else
362 		fid->uid = ~0;
363 
364 #ifdef CONFIG_9P_FSCACHE
365 	/* register the session for caching */
366 	v9fs_cache_session_get_cookie(v9ses);
367 #endif
368 
369 	return fid;
370 
371 error:
372 	bdi_destroy(&v9ses->bdi);
373 	return ERR_PTR(retval);
374 }
375 
376 /**
377  * v9fs_session_close - shutdown a session
378  * @v9ses: session information structure
379  *
380  */
381 
382 void v9fs_session_close(struct v9fs_session_info *v9ses)
383 {
384 	if (v9ses->clnt) {
385 		p9_client_destroy(v9ses->clnt);
386 		v9ses->clnt = NULL;
387 	}
388 
389 #ifdef CONFIG_9P_FSCACHE
390 	if (v9ses->fscache) {
391 		v9fs_cache_session_put_cookie(v9ses);
392 		kfree(v9ses->cachetag);
393 	}
394 #endif
395 	__putname(v9ses->uname);
396 	__putname(v9ses->aname);
397 
398 	bdi_destroy(&v9ses->bdi);
399 
400 	spin_lock(&v9fs_sessionlist_lock);
401 	list_del(&v9ses->slist);
402 	spin_unlock(&v9fs_sessionlist_lock);
403 }
404 
405 /**
406  * v9fs_session_cancel - terminate a session
407  * @v9ses: session to terminate
408  *
409  * mark transport as disconnected and cancel all pending requests.
410  */
411 
412 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
413 	P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
414 	p9_client_disconnect(v9ses->clnt);
415 }
416 
417 /**
418  * v9fs_session_begin_cancel - Begin terminate of a session
419  * @v9ses: session to terminate
420  *
421  * After this call we don't allow any request other than clunk.
422  */
423 
424 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
425 {
426 	P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
427 	p9_client_begin_disconnect(v9ses->clnt);
428 }
429 
430 extern int v9fs_error_init(void);
431 
432 static struct kobject *v9fs_kobj;
433 
434 #ifdef CONFIG_9P_FSCACHE
435 /**
436  * caches_show - list caches associated with a session
437  *
438  * Returns the size of buffer written.
439  */
440 
441 static ssize_t caches_show(struct kobject *kobj,
442 			   struct kobj_attribute *attr,
443 			   char *buf)
444 {
445 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
446 	struct v9fs_session_info *v9ses;
447 
448 	spin_lock(&v9fs_sessionlist_lock);
449 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
450 		if (v9ses->cachetag) {
451 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
452 			if (n < 0) {
453 				count = n;
454 				break;
455 			}
456 
457 			count += n;
458 			limit -= n;
459 		}
460 	}
461 
462 	spin_unlock(&v9fs_sessionlist_lock);
463 	return count;
464 }
465 
466 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
467 #endif /* CONFIG_9P_FSCACHE */
468 
469 static struct attribute *v9fs_attrs[] = {
470 #ifdef CONFIG_9P_FSCACHE
471 	&v9fs_attr_cache.attr,
472 #endif
473 	NULL,
474 };
475 
476 static struct attribute_group v9fs_attr_group = {
477 	.attrs = v9fs_attrs,
478 };
479 
480 /**
481  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
482  *
483  */
484 
485 static int v9fs_sysfs_init(void)
486 {
487 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
488 	if (!v9fs_kobj)
489 		return -ENOMEM;
490 
491 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
492 		kobject_put(v9fs_kobj);
493 		return -ENOMEM;
494 	}
495 
496 	return 0;
497 }
498 
499 /**
500  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
501  *
502  */
503 
504 static void v9fs_sysfs_cleanup(void)
505 {
506 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
507 	kobject_put(v9fs_kobj);
508 }
509 
510 static void v9fs_inode_init_once(void *foo)
511 {
512 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
513 #ifdef CONFIG_9P_FSCACHE
514 	v9inode->fscache = NULL;
515 #endif
516 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
517 	inode_init_once(&v9inode->vfs_inode);
518 }
519 
520 /**
521  * v9fs_init_inode_cache - initialize a cache for 9P
522  * Returns 0 on success.
523  */
524 static int v9fs_init_inode_cache(void)
525 {
526 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
527 					  sizeof(struct v9fs_inode),
528 					  0, (SLAB_RECLAIM_ACCOUNT|
529 					      SLAB_MEM_SPREAD),
530 					  v9fs_inode_init_once);
531 	if (!v9fs_inode_cache)
532 		return -ENOMEM;
533 
534 	return 0;
535 }
536 
537 /**
538  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
539  *
540  */
541 static void v9fs_destroy_inode_cache(void)
542 {
543 	kmem_cache_destroy(v9fs_inode_cache);
544 }
545 
546 static int v9fs_cache_register(void)
547 {
548 	int ret;
549 	ret = v9fs_init_inode_cache();
550 	if (ret < 0)
551 		return ret;
552 #ifdef CONFIG_9P_FSCACHE
553 	return fscache_register_netfs(&v9fs_cache_netfs);
554 #else
555 	return ret;
556 #endif
557 }
558 
559 static void v9fs_cache_unregister(void)
560 {
561 	v9fs_destroy_inode_cache();
562 #ifdef CONFIG_9P_FSCACHE
563 	fscache_unregister_netfs(&v9fs_cache_netfs);
564 #endif
565 }
566 
567 /**
568  * init_v9fs - Initialize module
569  *
570  */
571 
572 static int __init init_v9fs(void)
573 {
574 	int err;
575 	printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
576 	/* TODO: Setup list of registered trasnport modules */
577 	err = register_filesystem(&v9fs_fs_type);
578 	if (err < 0) {
579 		printk(KERN_ERR "Failed to register filesystem\n");
580 		return err;
581 	}
582 
583 	err = v9fs_cache_register();
584 	if (err < 0) {
585 		printk(KERN_ERR "Failed to register v9fs for caching\n");
586 		goto out_fs_unreg;
587 	}
588 
589 	err = v9fs_sysfs_init();
590 	if (err < 0) {
591 		printk(KERN_ERR "Failed to register with sysfs\n");
592 		goto out_sysfs_cleanup;
593 	}
594 
595 	return 0;
596 
597 out_sysfs_cleanup:
598 	v9fs_sysfs_cleanup();
599 
600 out_fs_unreg:
601 	unregister_filesystem(&v9fs_fs_type);
602 
603 	return err;
604 }
605 
606 /**
607  * exit_v9fs - shutdown module
608  *
609  */
610 
611 static void __exit exit_v9fs(void)
612 {
613 	v9fs_sysfs_cleanup();
614 	v9fs_cache_unregister();
615 	unregister_filesystem(&v9fs_fs_type);
616 }
617 
618 module_init(init_v9fs)
619 module_exit(exit_v9fs)
620 
621 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
622 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
623 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
624 MODULE_LICENSE("GPL");
625