xref: /openbmc/linux/fs/9p/v9fs.c (revision 54525552) 
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 /**
82  * v9fs_parse_options - parse mount options into session structure
83  * @v9ses: existing v9fs session information
84  *
85  * Return 0 upon success, -ERRNO upon failure.
86  */
87 
88 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
89 {
90 	char *options, *tmp_options;
91 	substring_t args[MAX_OPT_ARGS];
92 	char *p;
93 	int option = 0;
94 	char *s, *e;
95 	int ret = 0;
96 
97 	/* setup defaults */
98 	v9ses->afid = ~0;
99 	v9ses->debug = 0;
100 	v9ses->cache = 0;
101 #ifdef CONFIG_9P_FSCACHE
102 	v9ses->cachetag = NULL;
103 #endif
104 
105 	if (!opts)
106 		return 0;
107 
108 	tmp_options = kstrdup(opts, GFP_KERNEL);
109 	if (!tmp_options) {
110 		ret = -ENOMEM;
111 		goto fail_option_alloc;
112 	}
113 	options = tmp_options;
114 
115 	while ((p = strsep(&options, ",")) != NULL) {
116 		int token;
117 		if (!*p)
118 			continue;
119 		token = match_token(p, tokens, args);
120 		if (token < Opt_uname) {
121 			int r = match_int(&args[0], &option);
122 			if (r < 0) {
123 				P9_DPRINTK(P9_DEBUG_ERROR,
124 					"integer field, but no integer?\n");
125 				ret = r;
126 				continue;
127 			}
128 		}
129 		switch (token) {
130 		case Opt_debug:
131 			v9ses->debug = option;
132 #ifdef CONFIG_NET_9P_DEBUG
133 			p9_debug_level = option;
134 #endif
135 			break;
136 
137 		case Opt_dfltuid:
138 			v9ses->dfltuid = option;
139 			break;
140 		case Opt_dfltgid:
141 			v9ses->dfltgid = option;
142 			break;
143 		case Opt_afid:
144 			v9ses->afid = option;
145 			break;
146 		case Opt_uname:
147 			match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
148 			break;
149 		case Opt_remotename:
150 			match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
151 			break;
152 		case Opt_nodevmap:
153 			v9ses->nodev = 1;
154 			break;
155 		case Opt_cache_loose:
156 			v9ses->cache = CACHE_LOOSE;
157 			break;
158 		case Opt_fscache:
159 			v9ses->cache = CACHE_FSCACHE;
160 			break;
161 		case Opt_cachetag:
162 #ifdef CONFIG_9P_FSCACHE
163 			v9ses->cachetag = match_strdup(&args[0]);
164 #endif
165 			break;
166 		case Opt_cache:
167 			s = match_strdup(&args[0]);
168 			if (!s) {
169 				ret = -ENOMEM;
170 				P9_DPRINTK(P9_DEBUG_ERROR,
171 				  "problem allocating copy of cache arg\n");
172 				goto free_and_return;
173 			}
174 
175 			if (strcmp(s, "loose") == 0)
176 				v9ses->cache = CACHE_LOOSE;
177 			else if (strcmp(s, "fscache") == 0)
178 				v9ses->cache = CACHE_FSCACHE;
179 			else
180 				v9ses->cache = CACHE_NONE;
181 			kfree(s);
182 			break;
183 
184 		case Opt_access:
185 			s = match_strdup(&args[0]);
186 			if (!s) {
187 				ret = -ENOMEM;
188 				P9_DPRINTK(P9_DEBUG_ERROR,
189 				  "problem allocating copy of access arg\n");
190 				goto free_and_return;
191 			}
192 
193 			v9ses->flags &= ~V9FS_ACCESS_MASK;
194 			if (strcmp(s, "user") == 0)
195 				v9ses->flags |= V9FS_ACCESS_USER;
196 			else if (strcmp(s, "any") == 0)
197 				v9ses->flags |= V9FS_ACCESS_ANY;
198 			else if (strcmp(s, "client") == 0) {
199 				v9ses->flags |= V9FS_ACCESS_CLIENT;
200 			} else {
201 				v9ses->flags |= V9FS_ACCESS_SINGLE;
202 				v9ses->uid = simple_strtoul(s, &e, 10);
203 				if (*e != '\0')
204 					v9ses->uid = ~0;
205 			}
206 			kfree(s);
207 			break;
208 
209 		case Opt_posixacl:
210 #ifdef CONFIG_9P_FS_POSIX_ACL
211 			v9ses->flags |= V9FS_POSIX_ACL;
212 #else
213 			P9_DPRINTK(P9_DEBUG_ERROR,
214 					"Not defined CONFIG_9P_FS_POSIX_ACL. "
215 					"Ignoring posixacl option\n");
216 #endif
217 			break;
218 
219 		default:
220 			continue;
221 		}
222 	}
223 
224 free_and_return:
225 	kfree(tmp_options);
226 fail_option_alloc:
227 	return ret;
228 }
229 
230 /**
231  * v9fs_session_init - initialize session
232  * @v9ses: session information structure
233  * @dev_name: device being mounted
234  * @data: options
235  *
236  */
237 
238 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
239 		  const char *dev_name, char *data)
240 {
241 	int retval = -EINVAL;
242 	struct p9_fid *fid;
243 	int rc;
244 
245 	v9ses->uname = __getname();
246 	if (!v9ses->uname)
247 		return ERR_PTR(-ENOMEM);
248 
249 	v9ses->aname = __getname();
250 	if (!v9ses->aname) {
251 		__putname(v9ses->uname);
252 		return ERR_PTR(-ENOMEM);
253 	}
254 	init_rwsem(&v9ses->rename_sem);
255 
256 	rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
257 	if (rc) {
258 		__putname(v9ses->aname);
259 		__putname(v9ses->uname);
260 		return ERR_PTR(rc);
261 	}
262 
263 	spin_lock(&v9fs_sessionlist_lock);
264 	list_add(&v9ses->slist, &v9fs_sessionlist);
265 	spin_unlock(&v9fs_sessionlist_lock);
266 
267 	strcpy(v9ses->uname, V9FS_DEFUSER);
268 	strcpy(v9ses->aname, V9FS_DEFANAME);
269 	v9ses->uid = ~0;
270 	v9ses->dfltuid = V9FS_DEFUID;
271 	v9ses->dfltgid = V9FS_DEFGID;
272 
273 	v9ses->clnt = p9_client_create(dev_name, data);
274 	if (IS_ERR(v9ses->clnt)) {
275 		retval = PTR_ERR(v9ses->clnt);
276 		v9ses->clnt = NULL;
277 		P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
278 		goto error;
279 	}
280 
281 	v9ses->flags = V9FS_ACCESS_USER;
282 
283 	if (p9_is_proto_dotl(v9ses->clnt)) {
284 		v9ses->flags = V9FS_ACCESS_CLIENT;
285 		v9ses->flags |= V9FS_PROTO_2000L;
286 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
287 		v9ses->flags |= V9FS_PROTO_2000U;
288 	}
289 
290 	rc = v9fs_parse_options(v9ses, data);
291 	if (rc < 0) {
292 		retval = rc;
293 		goto error;
294 	}
295 
296 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
297 
298 	if (!v9fs_proto_dotl(v9ses) &&
299 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
300 		/*
301 		 * We support ACCESS_CLIENT only for dotl.
302 		 * Fall back to ACCESS_USER
303 		 */
304 		v9ses->flags &= ~V9FS_ACCESS_MASK;
305 		v9ses->flags |= V9FS_ACCESS_USER;
306 	}
307 	/*FIXME !! */
308 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
309 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
310 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
311 
312 		v9ses->flags &= ~V9FS_ACCESS_MASK;
313 		v9ses->flags |= V9FS_ACCESS_ANY;
314 		v9ses->uid = ~0;
315 	}
316 	if (!v9fs_proto_dotl(v9ses) ||
317 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
318 		/*
319 		 * We support ACL checks on clinet only if the protocol is
320 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
321 		 */
322 		v9ses->flags &= ~V9FS_ACL_MASK;
323 	}
324 
325 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
326 							v9ses->aname);
327 	if (IS_ERR(fid)) {
328 		retval = PTR_ERR(fid);
329 		fid = NULL;
330 		P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
331 		goto error;
332 	}
333 
334 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
335 		fid->uid = v9ses->uid;
336 	else
337 		fid->uid = ~0;
338 
339 #ifdef CONFIG_9P_FSCACHE
340 	/* register the session for caching */
341 	v9fs_cache_session_get_cookie(v9ses);
342 #endif
343 
344 	return fid;
345 
346 error:
347 	bdi_destroy(&v9ses->bdi);
348 	return ERR_PTR(retval);
349 }
350 
351 /**
352  * v9fs_session_close - shutdown a session
353  * @v9ses: session information structure
354  *
355  */
356 
357 void v9fs_session_close(struct v9fs_session_info *v9ses)
358 {
359 	if (v9ses->clnt) {
360 		p9_client_destroy(v9ses->clnt);
361 		v9ses->clnt = NULL;
362 	}
363 
364 #ifdef CONFIG_9P_FSCACHE
365 	if (v9ses->fscache) {
366 		v9fs_cache_session_put_cookie(v9ses);
367 		kfree(v9ses->cachetag);
368 	}
369 #endif
370 	__putname(v9ses->uname);
371 	__putname(v9ses->aname);
372 
373 	bdi_destroy(&v9ses->bdi);
374 
375 	spin_lock(&v9fs_sessionlist_lock);
376 	list_del(&v9ses->slist);
377 	spin_unlock(&v9fs_sessionlist_lock);
378 }
379 
380 /**
381  * v9fs_session_cancel - terminate a session
382  * @v9ses: session to terminate
383  *
384  * mark transport as disconnected and cancel all pending requests.
385  */
386 
387 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
388 	P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
389 	p9_client_disconnect(v9ses->clnt);
390 }
391 
392 /**
393  * v9fs_session_begin_cancel - Begin terminate of a session
394  * @v9ses: session to terminate
395  *
396  * After this call we don't allow any request other than clunk.
397  */
398 
399 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
400 {
401 	P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
402 	p9_client_begin_disconnect(v9ses->clnt);
403 }
404 
405 extern int v9fs_error_init(void);
406 
407 static struct kobject *v9fs_kobj;
408 
409 #ifdef CONFIG_9P_FSCACHE
410 /**
411  * caches_show - list caches associated with a session
412  *
413  * Returns the size of buffer written.
414  */
415 
416 static ssize_t caches_show(struct kobject *kobj,
417 			   struct kobj_attribute *attr,
418 			   char *buf)
419 {
420 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
421 	struct v9fs_session_info *v9ses;
422 
423 	spin_lock(&v9fs_sessionlist_lock);
424 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
425 		if (v9ses->cachetag) {
426 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
427 			if (n < 0) {
428 				count = n;
429 				break;
430 			}
431 
432 			count += n;
433 			limit -= n;
434 		}
435 	}
436 
437 	spin_unlock(&v9fs_sessionlist_lock);
438 	return count;
439 }
440 
441 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
442 #endif /* CONFIG_9P_FSCACHE */
443 
444 static struct attribute *v9fs_attrs[] = {
445 #ifdef CONFIG_9P_FSCACHE
446 	&v9fs_attr_cache.attr,
447 #endif
448 	NULL,
449 };
450 
451 static struct attribute_group v9fs_attr_group = {
452 	.attrs = v9fs_attrs,
453 };
454 
455 /**
456  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
457  *
458  */
459 
460 static int v9fs_sysfs_init(void)
461 {
462 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
463 	if (!v9fs_kobj)
464 		return -ENOMEM;
465 
466 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
467 		kobject_put(v9fs_kobj);
468 		return -ENOMEM;
469 	}
470 
471 	return 0;
472 }
473 
474 /**
475  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
476  *
477  */
478 
479 static void v9fs_sysfs_cleanup(void)
480 {
481 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
482 	kobject_put(v9fs_kobj);
483 }
484 
485 static void v9fs_inode_init_once(void *foo)
486 {
487 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
488 #ifdef CONFIG_9P_FSCACHE
489 	v9inode->fscache = NULL;
490 	v9inode->fscache_key = NULL;
491 #endif
492 	inode_init_once(&v9inode->vfs_inode);
493 }
494 
495 /**
496  * v9fs_init_inode_cache - initialize a cache for 9P
497  * Returns 0 on success.
498  */
499 static int v9fs_init_inode_cache(void)
500 {
501 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
502 					  sizeof(struct v9fs_inode),
503 					  0, (SLAB_RECLAIM_ACCOUNT|
504 					      SLAB_MEM_SPREAD),
505 					  v9fs_inode_init_once);
506 	if (!v9fs_inode_cache)
507 		return -ENOMEM;
508 
509 	return 0;
510 }
511 
512 /**
513  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
514  *
515  */
516 static void v9fs_destroy_inode_cache(void)
517 {
518 	kmem_cache_destroy(v9fs_inode_cache);
519 }
520 
521 static int v9fs_cache_register(void)
522 {
523 	int ret;
524 	ret = v9fs_init_inode_cache();
525 	if (ret < 0)
526 		return ret;
527 #ifdef CONFIG_9P_FSCACHE
528 	return fscache_register_netfs(&v9fs_cache_netfs);
529 #else
530 	return ret;
531 #endif
532 }
533 
534 static void v9fs_cache_unregister(void)
535 {
536 	v9fs_destroy_inode_cache();
537 #ifdef CONFIG_9P_FSCACHE
538 	fscache_unregister_netfs(&v9fs_cache_netfs);
539 #endif
540 }
541 
542 /**
543  * init_v9fs - Initialize module
544  *
545  */
546 
547 static int __init init_v9fs(void)
548 {
549 	int err;
550 	printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
551 	/* TODO: Setup list of registered trasnport modules */
552 	err = register_filesystem(&v9fs_fs_type);
553 	if (err < 0) {
554 		printk(KERN_ERR "Failed to register filesystem\n");
555 		return err;
556 	}
557 
558 	err = v9fs_cache_register();
559 	if (err < 0) {
560 		printk(KERN_ERR "Failed to register v9fs for caching\n");
561 		goto out_fs_unreg;
562 	}
563 
564 	err = v9fs_sysfs_init();
565 	if (err < 0) {
566 		printk(KERN_ERR "Failed to register with sysfs\n");
567 		goto out_sysfs_cleanup;
568 	}
569 
570 	return 0;
571 
572 out_sysfs_cleanup:
573 	v9fs_sysfs_cleanup();
574 
575 out_fs_unreg:
576 	unregister_filesystem(&v9fs_fs_type);
577 
578 	return err;
579 }
580 
581 /**
582  * exit_v9fs - shutdown module
583  *
584  */
585 
586 static void __exit exit_v9fs(void)
587 {
588 	v9fs_sysfs_cleanup();
589 	v9fs_cache_unregister();
590 	unregister_filesystem(&v9fs_fs_type);
591 }
592 
593 module_init(init_v9fs)
594 module_exit(exit_v9fs)
595 
596 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
597 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
598 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
599 MODULE_LICENSE("GPL");
600