xref: /openbmc/linux/fs/9p/v9fs.c (revision b6dcefde) 
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 <net/9p/9p.h>
33 #include <net/9p/client.h>
34 #include <net/9p/transport.h>
35 #include "v9fs.h"
36 #include "v9fs_vfs.h"
37 #include "cache.h"
38 
39 static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
40 static LIST_HEAD(v9fs_sessionlist);
41 
42 /*
43  * Option Parsing (code inspired by NFS code)
44  *  NOTE: each transport will parse its own options
45  */
46 
47 enum {
48 	/* Options that take integer arguments */
49 	Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
50 	/* String options */
51 	Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
52 	/* Options that take no arguments */
53 	Opt_nodevmap,
54 	/* Cache options */
55 	Opt_cache_loose, Opt_fscache,
56 	/* Access options */
57 	Opt_access,
58 	/* Error token */
59 	Opt_err
60 };
61 
62 static const match_table_t tokens = {
63 	{Opt_debug, "debug=%x"},
64 	{Opt_dfltuid, "dfltuid=%u"},
65 	{Opt_dfltgid, "dfltgid=%u"},
66 	{Opt_afid, "afid=%u"},
67 	{Opt_uname, "uname=%s"},
68 	{Opt_remotename, "aname=%s"},
69 	{Opt_nodevmap, "nodevmap"},
70 	{Opt_cache, "cache=%s"},
71 	{Opt_cache_loose, "loose"},
72 	{Opt_fscache, "fscache"},
73 	{Opt_cachetag, "cachetag=%s"},
74 	{Opt_access, "access=%s"},
75 	{Opt_err, NULL}
76 };
77 
78 /**
79  * v9fs_parse_options - parse mount options into session structure
80  * @v9ses: existing v9fs session information
81  *
82  * Return 0 upon success, -ERRNO upon failure.
83  */
84 
85 static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
86 {
87 	char *options, *tmp_options;
88 	substring_t args[MAX_OPT_ARGS];
89 	char *p;
90 	int option = 0;
91 	char *s, *e;
92 	int ret = 0;
93 
94 	/* setup defaults */
95 	v9ses->afid = ~0;
96 	v9ses->debug = 0;
97 	v9ses->cache = 0;
98 #ifdef CONFIG_9P_FSCACHE
99 	v9ses->cachetag = NULL;
100 #endif
101 
102 	if (!opts)
103 		return 0;
104 
105 	tmp_options = kstrdup(opts, GFP_KERNEL);
106 	if (!tmp_options) {
107 		ret = -ENOMEM;
108 		goto fail_option_alloc;
109 	}
110 	options = tmp_options;
111 
112 	while ((p = strsep(&options, ",")) != NULL) {
113 		int token;
114 		if (!*p)
115 			continue;
116 		token = match_token(p, tokens, args);
117 		if (token < Opt_uname) {
118 			int r = match_int(&args[0], &option);
119 			if (r < 0) {
120 				P9_DPRINTK(P9_DEBUG_ERROR,
121 					"integer field, but no integer?\n");
122 				ret = r;
123 				continue;
124 			}
125 		}
126 		switch (token) {
127 		case Opt_debug:
128 			v9ses->debug = option;
129 #ifdef CONFIG_NET_9P_DEBUG
130 			p9_debug_level = option;
131 #endif
132 			break;
133 
134 		case Opt_dfltuid:
135 			v9ses->dfltuid = option;
136 			break;
137 		case Opt_dfltgid:
138 			v9ses->dfltgid = option;
139 			break;
140 		case Opt_afid:
141 			v9ses->afid = option;
142 			break;
143 		case Opt_uname:
144 			match_strlcpy(v9ses->uname, &args[0], PATH_MAX);
145 			break;
146 		case Opt_remotename:
147 			match_strlcpy(v9ses->aname, &args[0], PATH_MAX);
148 			break;
149 		case Opt_nodevmap:
150 			v9ses->nodev = 1;
151 			break;
152 		case Opt_cache_loose:
153 			v9ses->cache = CACHE_LOOSE;
154 			break;
155 		case Opt_fscache:
156 			v9ses->cache = CACHE_FSCACHE;
157 			break;
158 		case Opt_cachetag:
159 #ifdef CONFIG_9P_FSCACHE
160 			v9ses->cachetag = match_strdup(&args[0]);
161 #endif
162 			break;
163 		case Opt_cache:
164 			s = match_strdup(&args[0]);
165 			if (!s) {
166 				ret = -ENOMEM;
167 				P9_DPRINTK(P9_DEBUG_ERROR,
168 				  "problem allocating copy of cache arg\n");
169 				goto free_and_return;
170 			}
171 
172 			if (strcmp(s, "loose") == 0)
173 				v9ses->cache = CACHE_LOOSE;
174 			else if (strcmp(s, "fscache") == 0)
175 				v9ses->cache = CACHE_FSCACHE;
176 			else
177 				v9ses->cache = CACHE_NONE;
178 			kfree(s);
179 			break;
180 
181 		case Opt_access:
182 			s = match_strdup(&args[0]);
183 			if (!s) {
184 				ret = -ENOMEM;
185 				P9_DPRINTK(P9_DEBUG_ERROR,
186 				  "problem allocating copy of access arg\n");
187 				goto free_and_return;
188 			}
189 
190 			v9ses->flags &= ~V9FS_ACCESS_MASK;
191 			if (strcmp(s, "user") == 0)
192 				v9ses->flags |= V9FS_ACCESS_USER;
193 			else if (strcmp(s, "any") == 0)
194 				v9ses->flags |= V9FS_ACCESS_ANY;
195 			else {
196 				v9ses->flags |= V9FS_ACCESS_SINGLE;
197 				v9ses->uid = simple_strtoul(s, &e, 10);
198 				if (*e != '\0')
199 					v9ses->uid = ~0;
200 			}
201 			kfree(s);
202 			break;
203 
204 		default:
205 			continue;
206 		}
207 	}
208 
209 free_and_return:
210 	kfree(tmp_options);
211 fail_option_alloc:
212 	return ret;
213 }
214 
215 /**
216  * v9fs_session_init - initialize session
217  * @v9ses: session information structure
218  * @dev_name: device being mounted
219  * @data: options
220  *
221  */
222 
223 struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
224 		  const char *dev_name, char *data)
225 {
226 	int retval = -EINVAL;
227 	struct p9_fid *fid;
228 	int rc;
229 
230 	v9ses->uname = __getname();
231 	if (!v9ses->uname)
232 		return ERR_PTR(-ENOMEM);
233 
234 	v9ses->aname = __getname();
235 	if (!v9ses->aname) {
236 		__putname(v9ses->uname);
237 		return ERR_PTR(-ENOMEM);
238 	}
239 
240 	spin_lock(&v9fs_sessionlist_lock);
241 	list_add(&v9ses->slist, &v9fs_sessionlist);
242 	spin_unlock(&v9fs_sessionlist_lock);
243 
244 	v9ses->flags = V9FS_EXTENDED | V9FS_ACCESS_USER;
245 	strcpy(v9ses->uname, V9FS_DEFUSER);
246 	strcpy(v9ses->aname, V9FS_DEFANAME);
247 	v9ses->uid = ~0;
248 	v9ses->dfltuid = V9FS_DEFUID;
249 	v9ses->dfltgid = V9FS_DEFGID;
250 
251 	rc = v9fs_parse_options(v9ses, data);
252 	if (rc < 0) {
253 		retval = rc;
254 		goto error;
255 	}
256 
257 	v9ses->clnt = p9_client_create(dev_name, data);
258 	if (IS_ERR(v9ses->clnt)) {
259 		retval = PTR_ERR(v9ses->clnt);
260 		v9ses->clnt = NULL;
261 		P9_DPRINTK(P9_DEBUG_ERROR, "problem initializing 9p client\n");
262 		goto error;
263 	}
264 
265 	if (!v9ses->clnt->dotu)
266 		v9ses->flags &= ~V9FS_EXTENDED;
267 
268 	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
269 
270 	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
271 	if (!v9fs_extended(v9ses) &&
272 		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
273 
274 		v9ses->flags &= ~V9FS_ACCESS_MASK;
275 		v9ses->flags |= V9FS_ACCESS_ANY;
276 		v9ses->uid = ~0;
277 	}
278 
279 	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, ~0,
280 							v9ses->aname);
281 	if (IS_ERR(fid)) {
282 		retval = PTR_ERR(fid);
283 		fid = NULL;
284 		P9_DPRINTK(P9_DEBUG_ERROR, "cannot attach\n");
285 		goto error;
286 	}
287 
288 	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
289 		fid->uid = v9ses->uid;
290 	else
291 		fid->uid = ~0;
292 
293 #ifdef CONFIG_9P_FSCACHE
294 	/* register the session for caching */
295 	v9fs_cache_session_get_cookie(v9ses);
296 #endif
297 
298 	return fid;
299 
300 error:
301 	return ERR_PTR(retval);
302 }
303 
304 /**
305  * v9fs_session_close - shutdown a session
306  * @v9ses: session information structure
307  *
308  */
309 
310 void v9fs_session_close(struct v9fs_session_info *v9ses)
311 {
312 	if (v9ses->clnt) {
313 		p9_client_destroy(v9ses->clnt);
314 		v9ses->clnt = NULL;
315 	}
316 
317 #ifdef CONFIG_9P_FSCACHE
318 	if (v9ses->fscache) {
319 		v9fs_cache_session_put_cookie(v9ses);
320 		kfree(v9ses->cachetag);
321 	}
322 #endif
323 	__putname(v9ses->uname);
324 	__putname(v9ses->aname);
325 
326 	spin_lock(&v9fs_sessionlist_lock);
327 	list_del(&v9ses->slist);
328 	spin_unlock(&v9fs_sessionlist_lock);
329 }
330 
331 /**
332  * v9fs_session_cancel - terminate a session
333  * @v9ses: session to terminate
334  *
335  * mark transport as disconnected and cancel all pending requests.
336  */
337 
338 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
339 	P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
340 	p9_client_disconnect(v9ses->clnt);
341 }
342 
343 extern int v9fs_error_init(void);
344 
345 static struct kobject *v9fs_kobj;
346 
347 #ifdef CONFIG_9P_FSCACHE
348 /**
349  * caches_show - list caches associated with a session
350  *
351  * Returns the size of buffer written.
352  */
353 
354 static ssize_t caches_show(struct kobject *kobj,
355 			   struct kobj_attribute *attr,
356 			   char *buf)
357 {
358 	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
359 	struct v9fs_session_info *v9ses;
360 
361 	spin_lock(&v9fs_sessionlist_lock);
362 	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
363 		if (v9ses->cachetag) {
364 			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
365 			if (n < 0) {
366 				count = n;
367 				break;
368 			}
369 
370 			count += n;
371 			limit -= n;
372 		}
373 	}
374 
375 	spin_unlock(&v9fs_sessionlist_lock);
376 	return count;
377 }
378 
379 static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
380 #endif /* CONFIG_9P_FSCACHE */
381 
382 static struct attribute *v9fs_attrs[] = {
383 #ifdef CONFIG_9P_FSCACHE
384 	&v9fs_attr_cache.attr,
385 #endif
386 	NULL,
387 };
388 
389 static struct attribute_group v9fs_attr_group = {
390 	.attrs = v9fs_attrs,
391 };
392 
393 /**
394  * v9fs_sysfs_init - Initialize the v9fs sysfs interface
395  *
396  */
397 
398 static int v9fs_sysfs_init(void)
399 {
400 	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
401 	if (!v9fs_kobj)
402 		return -ENOMEM;
403 
404 	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
405 		kobject_put(v9fs_kobj);
406 		return -ENOMEM;
407 	}
408 
409 	return 0;
410 }
411 
412 /**
413  * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
414  *
415  */
416 
417 static void v9fs_sysfs_cleanup(void)
418 {
419 	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
420 	kobject_put(v9fs_kobj);
421 }
422 
423 /**
424  * init_v9fs - Initialize module
425  *
426  */
427 
428 static int __init init_v9fs(void)
429 {
430 	int err;
431 	printk(KERN_INFO "Installing v9fs 9p2000 file system support\n");
432 	/* TODO: Setup list of registered trasnport modules */
433 	err = register_filesystem(&v9fs_fs_type);
434 	if (err < 0) {
435 		printk(KERN_ERR "Failed to register filesystem\n");
436 		return err;
437 	}
438 
439 	err = v9fs_cache_register();
440 	if (err < 0) {
441 		printk(KERN_ERR "Failed to register v9fs for caching\n");
442 		goto out_fs_unreg;
443 	}
444 
445 	err = v9fs_sysfs_init();
446 	if (err < 0) {
447 		printk(KERN_ERR "Failed to register with sysfs\n");
448 		goto out_sysfs_cleanup;
449 	}
450 
451 	return 0;
452 
453 out_sysfs_cleanup:
454 	v9fs_sysfs_cleanup();
455 
456 out_fs_unreg:
457 	unregister_filesystem(&v9fs_fs_type);
458 
459 	return err;
460 }
461 
462 /**
463  * exit_v9fs - shutdown module
464  *
465  */
466 
467 static void __exit exit_v9fs(void)
468 {
469 	v9fs_sysfs_cleanup();
470 	v9fs_cache_unregister();
471 	unregister_filesystem(&v9fs_fs_type);
472 }
473 
474 module_init(init_v9fs)
475 module_exit(exit_v9fs)
476 
477 MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
478 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
479 MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
480 MODULE_LICENSE("GPL");
481