xref: /openbmc/linux/fs/9p/v9fs.c (revision 171f1bc7) 
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, r;
136 		if (!*p)
137 			continue;
138 		token = match_token(p, tokens, args);
139 		switch (token) {
140 		case Opt_debug:
141 			r = match_int(&args[0], &option);
142 			if (r < 0) {
143 				P9_DPRINTK(P9_DEBUG_ERROR,
144 					   "integer field, but no integer?\n");
145 				ret = r;
146 				continue;
147 			}
148 			v9ses->debug = option;
149 #ifdef CONFIG_NET_9P_DEBUG
150 			p9_debug_level = option;
151 #endif
152 			break;
153 
154 		case Opt_dfltuid:
155 			r = match_int(&args[0], &option);
156 			if (r < 0) {
157 				P9_DPRINTK(P9_DEBUG_ERROR,
158 					   "integer field, but no integer?\n");
159 				ret = r;
160 				continue;
161 			}
162 			v9ses->dfltuid = option;
163 			break;
164 		case Opt_dfltgid:
165 			r = match_int(&args[0], &option);
166 			if (r < 0) {
167 				P9_DPRINTK(P9_DEBUG_ERROR,
168 					   "integer field, but no integer?\n");
169 				ret = r;
170 				continue;
171 			}
172 			v9ses->dfltgid = option;
173 			break;
174 		case Opt_afid:
175 			r = match_int(&args[0], &option);
176 			if (r < 0) {
177 				P9_DPRINTK(P9_DEBUG_ERROR,
178 					   "integer field, but no integer?\n");
179 				ret = r;
180 				continue;
181 			}
182 			v9ses->afid = option;
183 			break;
184 		case Opt_uname:
185 			match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
186 			break;
187 		case Opt_remotename:
188 			match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
189 			break;
190 		case Opt_nodevmap:
191 			v9ses->nodev = 1;
192 			break;
193 		case Opt_cache_loose:
194 			v9ses->cache = CACHE_LOOSE;
195 			break;
196 		case Opt_fscache:
197 			v9ses->cache = CACHE_FSCACHE;
198 			break;
199 		case Opt_cachetag:
200 #ifdef CONFIG_9P_FSCACHE
201 			v9ses->cachetag = match_strdup(&args[0]);
202 #endif
203 			break;
204 		case Opt_cache:
205 			s = match_strdup(&args[0]);
206 			if (!s) {
207 				ret = -ENOMEM;
208 				P9_DPRINTK(P9_DEBUG_ERROR,
209 				  "problem allocating copy of cache arg\n");
210 				goto free_and_return;
211 			}
212 			ret = get_cache_mode(s);
213 			if (ret == -EINVAL) {
214 				kfree(s);
215 				goto free_and_return;
216 			}
217 
218 			v9ses->cache = ret;
219 			kfree(s);
220 			break;
221 
222 		case Opt_access:
223 			s = match_strdup(&args[0]);
224 			if (!s) {
225 				ret = -ENOMEM;
226 				P9_DPRINTK(P9_DEBUG_ERROR,
227 				  "problem allocating copy of access arg\n");
228 				goto free_and_return;
229 			}
230 
231 			v9ses->flags &= ~V9FS_ACCESS_MASK;
232 			if (strcmp(s, "user") == 0)
233 				v9ses->flags |= V9FS_ACCESS_USER;
234 			else if (strcmp(s, "any") == 0)
235 				v9ses->flags |= V9FS_ACCESS_ANY;
236 			else if (strcmp(s, "client") == 0) {
237 				v9ses->flags |= V9FS_ACCESS_CLIENT;
238 			} else {
239 				v9ses->flags |= V9FS_ACCESS_SINGLE;
240 				v9ses->uid = simple_strtoul(s, &e, 10);
241 				if (*e != '\0') {
242 					ret = -EINVAL;
243 					printk(KERN_INFO "9p: Unknown access "
244 							"argument %s.\n", s);
245 					kfree(s);
246 					goto free_and_return;
247 				}
248 			}
249 
250 			kfree(s);
251 			break;
252 
253 		case Opt_posixacl:
254 #ifdef CONFIG_9P_FS_POSIX_ACL
255 			v9ses->flags |= V9FS_POSIX_ACL;
256 #else
257 			P9_DPRINTK(P9_DEBUG_ERROR,
258 					"Not defined CONFIG_9P_FS_POSIX_ACL. "
259 					"Ignoring posixacl option\n");
260 #endif
261 			break;
262 
263 		default:
264 			continue;
265 		}
266 	}
267 
268 free_and_return:
269 	kfree(tmp_options);
270 fail_option_alloc:
271 	return ret;
272 }
273 
274 /**
275  * v9fs_session_init - initialize session
276  * @v9ses: session information structure
277  * @dev_name: device being mounted
278  * @data: options
279  *
280  */
281 
282 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
283 		  const char *dev_name, char *data)
284 {
285 	int retval = -EINVAL;
286 	struct p9_fid *fid;
287 	int rc;
288 
289 	v9ses->uname = __getname();
290 	if (!v9ses->uname)
291 		return ERR_PTR(-ENOMEM);
292 
293 	v9ses->aname = __getname();
294 	if (!v9ses->aname) {
295 		__putname(v9ses->uname);
296 		return ERR_PTR(-ENOMEM);
297 	}
298 	init_rwsem(&v9ses->rename_sem);
299 
300 	rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
301 	if (rc) {
302 		__putname(v9ses->aname);
303 		__putname(v9ses->uname);
304 		return ERR_PTR(rc);
305 	}
306 
307 	spin_lock(&v9fs_sessionlist_lock);
308 	list_add(&v9ses->slist, &v9fs_sessionlist);
309 	spin_unlock(&v9fs_sessionlist_lock);
310 
311 	strcpy(v9ses->uname, V9FS_DEFUSER);
312 	strcpy(v9ses->aname, V9FS_DEFANAME);
313 	v9ses->uid = ~0;
314 	v9ses->dfltuid = V9FS_DEFUID;
315 	v9ses->dfltgid = V9FS_DEFGID;
316 
317 	v9ses->clnt = p9_client_create(dev_name, data);
318 	if (IS_ERR(v9ses->clnt)) {
319 		retval = PTR_ERR(v9ses->clnt);
320 		v9ses->clnt = NULL;
321 		P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
322 		goto error;
323 	}
324 
325 	v9ses->flags = V9FS_ACCESS_USER;
326 
327 	if (p9_is_proto_dotl(v9ses->clnt)) {
328 		v9ses->flags = V9FS_ACCESS_CLIENT;
329 		v9ses->flags |= V9FS_PROTO_2000L;
330 	} else if (p9_is_proto_dotu(v9ses->clnt)) {
331 		v9ses->flags |= V9FS_PROTO_2000U;
332 	}
333 
334 	rc = v9fs_parse_options(v9ses, data);
335 	if (rc < 0) {
336 		retval = rc;
337 		goto error;
338 	}
339 
340 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
341 
342 	if (!v9fs_proto_dotl(v9ses) &&
343 	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
344 		/*
345 		 * We support ACCESS_CLIENT only for dotl.
346 		 * Fall back to ACCESS_USER
347 		 */
348 		v9ses->flags &= ~V9FS_ACCESS_MASK;
349 		v9ses->flags |= V9FS_ACCESS_USER;
350 	}
351 	/*FIXME !! */
352 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
353 	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
354 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
355 
356 		v9ses->flags &= ~V9FS_ACCESS_MASK;
357 		v9ses->flags |= V9FS_ACCESS_ANY;
358 		v9ses->uid = ~0;
359 	}
360 	if (!v9fs_proto_dotl(v9ses) ||
361 		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
362 		/*
363 		 * We support ACL checks on clinet only if the protocol is
364 		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
365 		 */
366 		v9ses->flags &= ~V9FS_ACL_MASK;
367 	}
368 
369 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
370 							v9ses->aname);
371 	if (IS_ERR(fid)) {
372 		retval = PTR_ERR(fid);
373 		fid = NULL;
374 		P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
375 		goto error;
376 	}
377 
378 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
379 		fid->uid = v9ses->uid;
380 	else
381 		fid->uid = ~0;
382 
383 #ifdef CONFIG_9P_FSCACHE
384 	/* register the session for caching */
385 	v9fs_cache_session_get_cookie(v9ses);
386 #endif
387 
388 	return fid;
389 
390 error:
391 	bdi_destroy(&v9ses->bdi);
392 	return ERR_PTR(retval);
393 }
394 
395 /**
396  * v9fs_session_close - shutdown a session
397  * @v9ses: session information structure
398  *
399  */
400 
401 void v9fs_session_close(struct v9fs_session_info *v9ses)
402 {
403 	if (v9ses->clnt) {
404 		p9_client_destroy(v9ses->clnt);
405 		v9ses->clnt = NULL;
406 	}
407 
408 #ifdef CONFIG_9P_FSCACHE
409 	if (v9ses->fscache) {
410 		v9fs_cache_session_put_cookie(v9ses);
411 		kfree(v9ses->cachetag);
412 	}
413 #endif
414 	__putname(v9ses->uname);
415 	__putname(v9ses->aname);
416 
417 	bdi_destroy(&v9ses->bdi);
418 
419 	spin_lock(&v9fs_sessionlist_lock);
420 	list_del(&v9ses->slist);
421 	spin_unlock(&v9fs_sessionlist_lock);
422 }
423 
424 /**
425  * v9fs_session_cancel - terminate a session
426  * @v9ses: session to terminate
427  *
428  * mark transport as disconnected and cancel all pending requests.
429  */
430 
431 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
432 	P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
433 	p9_client_disconnect(v9ses->clnt);
434 }
435 
436 /**
437  * v9fs_session_begin_cancel - Begin terminate of a session
438  * @v9ses: session to terminate
439  *
440  * After this call we don't allow any request other than clunk.
441  */
442 
443 void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
444 {
445 	P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
446 	p9_client_begin_disconnect(v9ses->clnt);
447 }
448 
449 extern int v9fs_error_init(void);
450 
451 static struct kobject *v9fs_kobj;
452 
453 #ifdef CONFIG_9P_FSCACHE
454 /**
455  * caches_show - list caches associated with a session
456  *
457  * Returns the size of buffer written.
458  */
459 
460 static ssize_t caches_show(struct kobject *kobj,
461 			   struct kobj_attribute *attr,
462 			   char *buf)
463 {
464 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
465 	struct v9fs_session_info *v9ses;
466 
467 	spin_lock(&v9fs_sessionlist_lock);
468 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
469 		if (v9ses->cachetag) {
470 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
471 			if (n < 0) {
472 				count = n;
473 				break;
474 			}
475 
476 			count += n;
477 			limit -= n;
478 		}
479 	}
480 
481 	spin_unlock(&v9fs_sessionlist_lock);
482 	return count;
483 }
484 
485 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
486 #endif /* CONFIG_9P_FSCACHE */
487 
488 static struct attribute *v9fs_attrs[] = {
489 #ifdef CONFIG_9P_FSCACHE
490 	&v9fs_attr_cache.attr,
491 #endif
492 	NULL,
493 };
494 
495 static struct attribute_group v9fs_attr_group = {
496 	.attrs = v9fs_attrs,
497 };
498 
499 /**
500  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
501  *
502  */
503 
504 static int v9fs_sysfs_init(void)
505 {
506 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
507 	if (!v9fs_kobj)
508 		return -ENOMEM;
509 
510 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
511 		kobject_put(v9fs_kobj);
512 		return -ENOMEM;
513 	}
514 
515 	return 0;
516 }
517 
518 /**
519  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
520  *
521  */
522 
523 static void v9fs_sysfs_cleanup(void)
524 {
525 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
526 	kobject_put(v9fs_kobj);
527 }
528 
529 static void v9fs_inode_init_once(void *foo)
530 {
531 	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
532 #ifdef CONFIG_9P_FSCACHE
533 	v9inode->fscache = NULL;
534 #endif
535 	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
536 	inode_init_once(&v9inode->vfs_inode);
537 }
538 
539 /**
540  * v9fs_init_inode_cache - initialize a cache for 9P
541  * Returns 0 on success.
542  */
543 static int v9fs_init_inode_cache(void)
544 {
545 	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
546 					  sizeof(struct v9fs_inode),
547 					  0, (SLAB_RECLAIM_ACCOUNT|
548 					      SLAB_MEM_SPREAD),
549 					  v9fs_inode_init_once);
550 	if (!v9fs_inode_cache)
551 		return -ENOMEM;
552 
553 	return 0;
554 }
555 
556 /**
557  * v9fs_destroy_inode_cache - destroy the cache of 9P inode
558  *
559  */
560 static void v9fs_destroy_inode_cache(void)
561 {
562 	kmem_cache_destroy(v9fs_inode_cache);
563 }
564 
565 static int v9fs_cache_register(void)
566 {
567 	int ret;
568 	ret = v9fs_init_inode_cache();
569 	if (ret < 0)
570 		return ret;
571 #ifdef CONFIG_9P_FSCACHE
572 	return fscache_register_netfs(&v9fs_cache_netfs);
573 #else
574 	return ret;
575 #endif
576 }
577 
578 static void v9fs_cache_unregister(void)
579 {
580 	v9fs_destroy_inode_cache();
581 #ifdef CONFIG_9P_FSCACHE
582 	fscache_unregister_netfs(&v9fs_cache_netfs);
583 #endif
584 }
585 
586 /**
587  * init_v9fs - Initialize module
588  *
589  */
590 
591 static int __init init_v9fs(void)
592 {
593 	int err;
594 	printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
595 	/* TODO: Setup list of registered trasnport modules */
596 	err = register_filesystem(&v9fs_fs_type);
597 	if (err < 0) {
598 		printk(KERN_ERR "Failed to register filesystem\n");
599 		return err;
600 	}
601 
602 	err = v9fs_cache_register();
603 	if (err < 0) {
604 		printk(KERN_ERR "Failed to register v9fs for caching\n");
605 		goto out_fs_unreg;
606 	}
607 
608 	err = v9fs_sysfs_init();
609 	if (err < 0) {
610 		printk(KERN_ERR "Failed to register with sysfs\n");
611 		goto out_sysfs_cleanup;
612 	}
613 
614 	return 0;
615 
616 out_sysfs_cleanup:
617 	v9fs_sysfs_cleanup();
618 
619 out_fs_unreg:
620 	unregister_filesystem(&v9fs_fs_type);
621 
622 	return err;
623 }
624 
625 /**
626  * exit_v9fs - shutdown module
627  *
628  */
629 
630 static void __exit exit_v9fs(void)
631 {
632 	v9fs_sysfs_cleanup();
633 	v9fs_cache_unregister();
634 	unregister_filesystem(&v9fs_fs_type);
635 }
636 
637 module_init(init_v9fs)
638 module_exit(exit_v9fs)
639 
640 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
641 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
642 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
643 MODULE_LICENSE("GPL");
644