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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/cred.h>
33#include <linux/parser.h>
34#include <linux/idr.h>
35#include <linux/slab.h>
36#include <linux/seq_file.h>
37#include <net/9p/9p.h>
38#include <net/9p/client.h>
39#include <net/9p/transport.h>
40#include "v9fs.h"
41#include "v9fs_vfs.h"
42#include "cache.h"
43
44static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
45static LIST_HEAD(v9fs_sessionlist);
46struct kmem_cache *v9fs_inode_cache;
47
48/*
49 * Option Parsing (code inspired by NFS code)
50 * NOTE: each transport will parse its own options
51 */
52
53enum {
54 /* Options that take integer arguments */
55 Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
56 /* String options */
57 Opt_uname, Opt_remotename, Opt_cache, Opt_cachetag,
58 /* Options that take no arguments */
59 Opt_nodevmap,
60 /* Cache options */
61 Opt_cache_loose, Opt_fscache, Opt_mmap,
62 /* Access options */
63 Opt_access, Opt_posixacl,
64 /* Error token */
65 Opt_err
66};
67
68static const match_table_t tokens = {
69 {Opt_debug, "debug=%x"},
70 {Opt_dfltuid, "dfltuid=%u"},
71 {Opt_dfltgid, "dfltgid=%u"},
72 {Opt_afid, "afid=%u"},
73 {Opt_uname, "uname=%s"},
74 {Opt_remotename, "aname=%s"},
75 {Opt_nodevmap, "nodevmap"},
76 {Opt_cache, "cache=%s"},
77 {Opt_cache_loose, "loose"},
78 {Opt_fscache, "fscache"},
79 {Opt_mmap, "mmap"},
80 {Opt_cachetag, "cachetag=%s"},
81 {Opt_access, "access=%s"},
82 {Opt_posixacl, "posixacl"},
83 {Opt_err, NULL}
84};
85
86static const char *const v9fs_cache_modes[nr__p9_cache_modes] = {
87 [CACHE_NONE] = "none",
88 [CACHE_MMAP] = "mmap",
89 [CACHE_LOOSE] = "loose",
90 [CACHE_FSCACHE] = "fscache",
91};
92
93/* Interpret mount options for cache mode */
94static int get_cache_mode(char *s)
95{
96 int version = -EINVAL;
97
98 if (!strcmp(s, "loose")) {
99 version = CACHE_LOOSE;
100 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
101 } else if (!strcmp(s, "fscache")) {
102 version = CACHE_FSCACHE;
103 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
104 } else if (!strcmp(s, "mmap")) {
105 version = CACHE_MMAP;
106 p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
107 } else if (!strcmp(s, "none")) {
108 version = CACHE_NONE;
109 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
110 } else
111 pr_info("Unknown Cache mode %s\n", s);
112 return version;
113}
114
115/*
116 * Display the mount options in /proc/mounts.
117 */
118int v9fs_show_options(struct seq_file *m, struct dentry *root)
119{
120 struct v9fs_session_info *v9ses = root->d_sb->s_fs_info;
121
122 if (v9ses->debug)
123 seq_printf(m, ",debug=%x", v9ses->debug);
124 if (!uid_eq(v9ses->dfltuid, V9FS_DEFUID))
125 seq_printf(m, ",dfltuid=%u",
126 from_kuid_munged(&init_user_ns, v9ses->dfltuid));
127 if (!gid_eq(v9ses->dfltgid, V9FS_DEFGID))
128 seq_printf(m, ",dfltgid=%u",
129 from_kgid_munged(&init_user_ns, v9ses->dfltgid));
130 if (v9ses->afid != ~0)
131 seq_printf(m, ",afid=%u", v9ses->afid);
132 if (strcmp(v9ses->uname, V9FS_DEFUSER) != 0)
133 seq_printf(m, ",uname=%s", v9ses->uname);
134 if (strcmp(v9ses->aname, V9FS_DEFANAME) != 0)
135 seq_printf(m, ",aname=%s", v9ses->aname);
136 if (v9ses->nodev)
137 seq_puts(m, ",nodevmap");
138 if (v9ses->cache)
139 seq_printf(m, ",%s", v9fs_cache_modes[v9ses->cache]);
140#ifdef CONFIG_9P_FSCACHE
141 if (v9ses->cachetag && v9ses->cache == CACHE_FSCACHE)
142 seq_printf(m, ",cachetag=%s", v9ses->cachetag);
143#endif
144
145 switch (v9ses->flags & V9FS_ACCESS_MASK) {
146 case V9FS_ACCESS_USER:
147 seq_puts(m, ",access=user");
148 break;
149 case V9FS_ACCESS_ANY:
150 seq_puts(m, ",access=any");
151 break;
152 case V9FS_ACCESS_CLIENT:
153 seq_puts(m, ",access=client");
154 break;
155 case V9FS_ACCESS_SINGLE:
156 seq_printf(m, ",access=%u",
157 from_kuid_munged(&init_user_ns, v9ses->uid));
158 break;
159 }
160
161 if (v9ses->flags & V9FS_POSIX_ACL)
162 seq_puts(m, ",posixacl");
163
164 return p9_show_client_options(m, v9ses->clnt);
165}
166
167/**
168 * v9fs_parse_options - parse mount options into session structure
169 * @v9ses: existing v9fs session information
170 *
171 * Return 0 upon success, -ERRNO upon failure.
172 */
173
174static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
175{
176 char *options, *tmp_options;
177 substring_t args[MAX_OPT_ARGS];
178 char *p;
179 int option = 0;
180 char *s, *e;
181 int ret = 0;
182
183 /* setup defaults */
184 v9ses->afid = ~0;
185 v9ses->debug = 0;
186 v9ses->cache = CACHE_NONE;
187#ifdef CONFIG_9P_FSCACHE
188 v9ses->cachetag = NULL;
189#endif
190
191 if (!opts)
192 return 0;
193
194 tmp_options = kstrdup(opts, GFP_KERNEL);
195 if (!tmp_options) {
196 ret = -ENOMEM;
197 goto fail_option_alloc;
198 }
199 options = tmp_options;
200
201 while ((p = strsep(&options, ",")) != NULL) {
202 int token, r;
203 if (!*p)
204 continue;
205 token = match_token(p, tokens, args);
206 switch (token) {
207 case Opt_debug:
208 r = match_int(&args[0], &option);
209 if (r < 0) {
210 p9_debug(P9_DEBUG_ERROR,
211 "integer field, but no integer?\n");
212 ret = r;
213 continue;
214 }
215 v9ses->debug = option;
216#ifdef CONFIG_NET_9P_DEBUG
217 p9_debug_level = option;
218#endif
219 break;
220
221 case Opt_dfltuid:
222 r = match_int(&args[0], &option);
223 if (r < 0) {
224 p9_debug(P9_DEBUG_ERROR,
225 "integer field, but no integer?\n");
226 ret = r;
227 continue;
228 }
229 v9ses->dfltuid = make_kuid(current_user_ns(), option);
230 if (!uid_valid(v9ses->dfltuid)) {
231 p9_debug(P9_DEBUG_ERROR,
232 "uid field, but not a uid?\n");
233 ret = -EINVAL;
234 continue;
235 }
236 break;
237 case Opt_dfltgid:
238 r = match_int(&args[0], &option);
239 if (r < 0) {
240 p9_debug(P9_DEBUG_ERROR,
241 "integer field, but no integer?\n");
242 ret = r;
243 continue;
244 }
245 v9ses->dfltgid = make_kgid(current_user_ns(), option);
246 if (!gid_valid(v9ses->dfltgid)) {
247 p9_debug(P9_DEBUG_ERROR,
248 "gid field, but not a gid?\n");
249 ret = -EINVAL;
250 continue;
251 }
252 break;
253 case Opt_afid:
254 r = match_int(&args[0], &option);
255 if (r < 0) {
256 p9_debug(P9_DEBUG_ERROR,
257 "integer field, but no integer?\n");
258 ret = r;
259 continue;
260 }
261 v9ses->afid = option;
262 break;
263 case Opt_uname:
264 kfree(v9ses->uname);
265 v9ses->uname = match_strdup(&args[0]);
266 if (!v9ses->uname) {
267 ret = -ENOMEM;
268 goto free_and_return;
269 }
270 break;
271 case Opt_remotename:
272 kfree(v9ses->aname);
273 v9ses->aname = match_strdup(&args[0]);
274 if (!v9ses->aname) {
275 ret = -ENOMEM;
276 goto free_and_return;
277 }
278 break;
279 case Opt_nodevmap:
280 v9ses->nodev = 1;
281 break;
282 case Opt_cache_loose:
283 v9ses->cache = CACHE_LOOSE;
284 break;
285 case Opt_fscache:
286 v9ses->cache = CACHE_FSCACHE;
287 break;
288 case Opt_mmap:
289 v9ses->cache = CACHE_MMAP;
290 break;
291 case Opt_cachetag:
292#ifdef CONFIG_9P_FSCACHE
293 kfree(v9ses->cachetag);
294 v9ses->cachetag = match_strdup(&args[0]);
295 if (!v9ses->cachetag) {
296 ret = -ENOMEM;
297 goto free_and_return;
298 }
299#endif
300 break;
301 case Opt_cache:
302 s = match_strdup(&args[0]);
303 if (!s) {
304 ret = -ENOMEM;
305 p9_debug(P9_DEBUG_ERROR,
306 "problem allocating copy of cache arg\n");
307 goto free_and_return;
308 }
309 ret = get_cache_mode(s);
310 if (ret == -EINVAL) {
311 kfree(s);
312 goto free_and_return;
313 }
314
315 v9ses->cache = ret;
316 kfree(s);
317 break;
318
319 case Opt_access:
320 s = match_strdup(&args[0]);
321 if (!s) {
322 ret = -ENOMEM;
323 p9_debug(P9_DEBUG_ERROR,
324 "problem allocating copy of access arg\n");
325 goto free_and_return;
326 }
327
328 v9ses->flags &= ~V9FS_ACCESS_MASK;
329 if (strcmp(s, "user") == 0)
330 v9ses->flags |= V9FS_ACCESS_USER;
331 else if (strcmp(s, "any") == 0)
332 v9ses->flags |= V9FS_ACCESS_ANY;
333 else if (strcmp(s, "client") == 0) {
334 v9ses->flags |= V9FS_ACCESS_CLIENT;
335 } else {
336 uid_t uid;
337 v9ses->flags |= V9FS_ACCESS_SINGLE;
338 uid = simple_strtoul(s, &e, 10);
339 if (*e != '\0') {
340 ret = -EINVAL;
341 pr_info("Unknown access argument %s\n",
342 s);
343 kfree(s);
344 goto free_and_return;
345 }
346 v9ses->uid = make_kuid(current_user_ns(), uid);
347 if (!uid_valid(v9ses->uid)) {
348 ret = -EINVAL;
349 pr_info("Uknown uid %s\n", s);
350 kfree(s);
351 goto free_and_return;
352 }
353 }
354
355 kfree(s);
356 break;
357
358 case Opt_posixacl:
359#ifdef CONFIG_9P_FS_POSIX_ACL
360 v9ses->flags |= V9FS_POSIX_ACL;
361#else
362 p9_debug(P9_DEBUG_ERROR,
363 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
364#endif
365 break;
366
367 default:
368 continue;
369 }
370 }
371
372free_and_return:
373 kfree(tmp_options);
374fail_option_alloc:
375 return ret;
376}
377
378/**
379 * v9fs_session_init - initialize session
380 * @v9ses: session information structure
381 * @dev_name: device being mounted
382 * @data: options
383 *
384 */
385
386struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
387 const char *dev_name, char *data)
388{
389 struct p9_fid *fid;
390 int rc = -ENOMEM;
391
392 v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
393 if (!v9ses->uname)
394 goto err_names;
395
396 v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
397 if (!v9ses->aname)
398 goto err_names;
399 init_rwsem(&v9ses->rename_sem);
400
401 v9ses->uid = INVALID_UID;
402 v9ses->dfltuid = V9FS_DEFUID;
403 v9ses->dfltgid = V9FS_DEFGID;
404
405 v9ses->clnt = p9_client_create(dev_name, data);
406 if (IS_ERR(v9ses->clnt)) {
407 rc = PTR_ERR(v9ses->clnt);
408 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
409 goto err_names;
410 }
411
412 v9ses->flags = V9FS_ACCESS_USER;
413
414 if (p9_is_proto_dotl(v9ses->clnt)) {
415 v9ses->flags = V9FS_ACCESS_CLIENT;
416 v9ses->flags |= V9FS_PROTO_2000L;
417 } else if (p9_is_proto_dotu(v9ses->clnt)) {
418 v9ses->flags |= V9FS_PROTO_2000U;
419 }
420
421 rc = v9fs_parse_options(v9ses, data);
422 if (rc < 0)
423 goto err_clnt;
424
425 v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
426
427 if (!v9fs_proto_dotl(v9ses) &&
428 ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
429 /*
430 * We support ACCESS_CLIENT only for dotl.
431 * Fall back to ACCESS_USER
432 */
433 v9ses->flags &= ~V9FS_ACCESS_MASK;
434 v9ses->flags |= V9FS_ACCESS_USER;
435 }
436 /*FIXME !! */
437 /* for legacy mode, fall back to V9FS_ACCESS_ANY */
438 if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
439 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
440
441 v9ses->flags &= ~V9FS_ACCESS_MASK;
442 v9ses->flags |= V9FS_ACCESS_ANY;
443 v9ses->uid = INVALID_UID;
444 }
445 if (!v9fs_proto_dotl(v9ses) ||
446 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
447 /*
448 * We support ACL checks on clinet only if the protocol is
449 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
450 */
451 v9ses->flags &= ~V9FS_ACL_MASK;
452 }
453
454 fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
455 v9ses->aname);
456 if (IS_ERR(fid)) {
457 rc = PTR_ERR(fid);
458 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
459 goto err_clnt;
460 }
461
462 if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
463 fid->uid = v9ses->uid;
464 else
465 fid->uid = INVALID_UID;
466
467#ifdef CONFIG_9P_FSCACHE
468 /* register the session for caching */
469 v9fs_cache_session_get_cookie(v9ses);
470#endif
471 spin_lock(&v9fs_sessionlist_lock);
472 list_add(&v9ses->slist, &v9fs_sessionlist);
473 spin_unlock(&v9fs_sessionlist_lock);
474
475 return fid;
476
477err_clnt:
478#ifdef CONFIG_9P_FSCACHE
479 kfree(v9ses->cachetag);
480#endif
481 p9_client_destroy(v9ses->clnt);
482err_names:
483 kfree(v9ses->uname);
484 kfree(v9ses->aname);
485 return ERR_PTR(rc);
486}
487
488/**
489 * v9fs_session_close - shutdown a session
490 * @v9ses: session information structure
491 *
492 */
493
494void v9fs_session_close(struct v9fs_session_info *v9ses)
495{
496 if (v9ses->clnt) {
497 p9_client_destroy(v9ses->clnt);
498 v9ses->clnt = NULL;
499 }
500
501#ifdef CONFIG_9P_FSCACHE
502 if (v9ses->fscache) {
503 v9fs_cache_session_put_cookie(v9ses);
504 kfree(v9ses->cachetag);
505 }
506#endif
507 kfree(v9ses->uname);
508 kfree(v9ses->aname);
509
510 spin_lock(&v9fs_sessionlist_lock);
511 list_del(&v9ses->slist);
512 spin_unlock(&v9fs_sessionlist_lock);
513}
514
515/**
516 * v9fs_session_cancel - terminate a session
517 * @v9ses: session to terminate
518 *
519 * mark transport as disconnected and cancel all pending requests.
520 */
521
522void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
523 p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
524 p9_client_disconnect(v9ses->clnt);
525}
526
527/**
528 * v9fs_session_begin_cancel - Begin terminate of a session
529 * @v9ses: session to terminate
530 *
531 * After this call we don't allow any request other than clunk.
532 */
533
534void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
535{
536 p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
537 p9_client_begin_disconnect(v9ses->clnt);
538}
539
540extern int v9fs_error_init(void);
541
542static struct kobject *v9fs_kobj;
543
544#ifdef CONFIG_9P_FSCACHE
545/**
546 * caches_show - list caches associated with a session
547 *
548 * Returns the size of buffer written.
549 */
550
551static ssize_t caches_show(struct kobject *kobj,
552 struct kobj_attribute *attr,
553 char *buf)
554{
555 ssize_t n = 0, count = 0, limit = PAGE_SIZE;
556 struct v9fs_session_info *v9ses;
557
558 spin_lock(&v9fs_sessionlist_lock);
559 list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
560 if (v9ses->cachetag) {
561 n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
562 if (n < 0) {
563 count = n;
564 break;
565 }
566
567 count += n;
568 limit -= n;
569 }
570 }
571
572 spin_unlock(&v9fs_sessionlist_lock);
573 return count;
574}
575
576static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
577#endif /* CONFIG_9P_FSCACHE */
578
579static struct attribute *v9fs_attrs[] = {
580#ifdef CONFIG_9P_FSCACHE
581 &v9fs_attr_cache.attr,
582#endif
583 NULL,
584};
585
586static struct attribute_group v9fs_attr_group = {
587 .attrs = v9fs_attrs,
588};
589
590/**
591 * v9fs_sysfs_init - Initialize the v9fs sysfs interface
592 *
593 */
594
595static int __init v9fs_sysfs_init(void)
596{
597 v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
598 if (!v9fs_kobj)
599 return -ENOMEM;
600
601 if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
602 kobject_put(v9fs_kobj);
603 return -ENOMEM;
604 }
605
606 return 0;
607}
608
609/**
610 * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
611 *
612 */
613
614static void v9fs_sysfs_cleanup(void)
615{
616 sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
617 kobject_put(v9fs_kobj);
618}
619
620static void v9fs_inode_init_once(void *foo)
621{
622 struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
623#ifdef CONFIG_9P_FSCACHE
624 v9inode->fscache = NULL;
625#endif
626 memset(&v9inode->qid, 0, sizeof(v9inode->qid));
627 inode_init_once(&v9inode->vfs_inode);
628}
629
630/**
631 * v9fs_init_inode_cache - initialize a cache for 9P
632 * Returns 0 on success.
633 */
634static int v9fs_init_inode_cache(void)
635{
636 v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
637 sizeof(struct v9fs_inode),
638 0, (SLAB_RECLAIM_ACCOUNT|
639 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
640 v9fs_inode_init_once);
641 if (!v9fs_inode_cache)
642 return -ENOMEM;
643
644 return 0;
645}
646
647/**
648 * v9fs_destroy_inode_cache - destroy the cache of 9P inode
649 *
650 */
651static void v9fs_destroy_inode_cache(void)
652{
653 /*
654 * Make sure all delayed rcu free inodes are flushed before we
655 * destroy cache.
656 */
657 rcu_barrier();
658 kmem_cache_destroy(v9fs_inode_cache);
659}
660
661static int v9fs_cache_register(void)
662{
663 int ret;
664 ret = v9fs_init_inode_cache();
665 if (ret < 0)
666 return ret;
667#ifdef CONFIG_9P_FSCACHE
668 ret = fscache_register_netfs(&v9fs_cache_netfs);
669 if (ret < 0)
670 v9fs_destroy_inode_cache();
671#endif
672 return ret;
673}
674
675static void v9fs_cache_unregister(void)
676{
677 v9fs_destroy_inode_cache();
678#ifdef CONFIG_9P_FSCACHE
679 fscache_unregister_netfs(&v9fs_cache_netfs);
680#endif
681}
682
683/**
684 * init_v9fs - Initialize module
685 *
686 */
687
688static int __init init_v9fs(void)
689{
690 int err;
691 pr_info("Installing v9fs 9p2000 file system support\n");
692 /* TODO: Setup list of registered trasnport modules */
693
694 err = v9fs_cache_register();
695 if (err < 0) {
696 pr_err("Failed to register v9fs for caching\n");
697 return err;
698 }
699
700 err = v9fs_sysfs_init();
701 if (err < 0) {
702 pr_err("Failed to register with sysfs\n");
703 goto out_cache;
704 }
705 err = register_filesystem(&v9fs_fs_type);
706 if (err < 0) {
707 pr_err("Failed to register filesystem\n");
708 goto out_sysfs_cleanup;
709 }
710
711 return 0;
712
713out_sysfs_cleanup:
714 v9fs_sysfs_cleanup();
715
716out_cache:
717 v9fs_cache_unregister();
718
719 return err;
720}
721
722/**
723 * exit_v9fs - shutdown module
724 *
725 */
726
727static void __exit exit_v9fs(void)
728{
729 v9fs_sysfs_cleanup();
730 v9fs_cache_unregister();
731 unregister_filesystem(&v9fs_fs_type);
732}
733
734module_init(init_v9fs)
735module_exit(exit_v9fs)
736
737MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
738MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
739MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
740MODULE_LICENSE("GPL");
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
42static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
43static LIST_HEAD(v9fs_sessionlist);
44struct 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
51enum {
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, Opt_mmap,
60 /* Access options */
61 Opt_access, Opt_posixacl,
62 /* Error token */
63 Opt_err
64};
65
66static 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_mmap, "mmap"},
78 {Opt_cachetag, "cachetag=%s"},
79 {Opt_access, "access=%s"},
80 {Opt_posixacl, "posixacl"},
81 {Opt_err, NULL}
82};
83
84/* Interpret mount options for cache mode */
85static int get_cache_mode(char *s)
86{
87 int version = -EINVAL;
88
89 if (!strcmp(s, "loose")) {
90 version = CACHE_LOOSE;
91 p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
92 } else if (!strcmp(s, "fscache")) {
93 version = CACHE_FSCACHE;
94 p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
95 } else if (!strcmp(s, "mmap")) {
96 version = CACHE_MMAP;
97 p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
98 } else if (!strcmp(s, "none")) {
99 version = CACHE_NONE;
100 p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
101 } else
102 pr_info("Unknown Cache mode %s\n", s);
103 return version;
104}
105
106/**
107 * v9fs_parse_options - parse mount options into session structure
108 * @v9ses: existing v9fs session information
109 *
110 * Return 0 upon success, -ERRNO upon failure.
111 */
112
113static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
114{
115 char *options, *tmp_options;
116 substring_t args[MAX_OPT_ARGS];
117 char *p;
118 int option = 0;
119 char *s, *e;
120 int ret = 0;
121
122 /* setup defaults */
123 v9ses->afid = ~0;
124 v9ses->debug = 0;
125 v9ses->cache = CACHE_NONE;
126#ifdef CONFIG_9P_FSCACHE
127 v9ses->cachetag = NULL;
128#endif
129
130 if (!opts)
131 return 0;
132
133 tmp_options = kstrdup(opts, GFP_KERNEL);
134 if (!tmp_options) {
135 ret = -ENOMEM;
136 goto fail_option_alloc;
137 }
138 options = tmp_options;
139
140 while ((p = strsep(&options, ",")) != NULL) {
141 int token, r;
142 if (!*p)
143 continue;
144 token = match_token(p, tokens, args);
145 switch (token) {
146 case Opt_debug:
147 r = match_int(&args[0], &option);
148 if (r < 0) {
149 p9_debug(P9_DEBUG_ERROR,
150 "integer field, but no integer?\n");
151 ret = r;
152 continue;
153 }
154 v9ses->debug = option;
155#ifdef CONFIG_NET_9P_DEBUG
156 p9_debug_level = option;
157#endif
158 break;
159
160 case Opt_dfltuid:
161 r = match_int(&args[0], &option);
162 if (r < 0) {
163 p9_debug(P9_DEBUG_ERROR,
164 "integer field, but no integer?\n");
165 ret = r;
166 continue;
167 }
168 v9ses->dfltuid = make_kuid(current_user_ns(), option);
169 if (!uid_valid(v9ses->dfltuid)) {
170 p9_debug(P9_DEBUG_ERROR,
171 "uid field, but not a uid?\n");
172 ret = -EINVAL;
173 continue;
174 }
175 break;
176 case Opt_dfltgid:
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->dfltgid = make_kgid(current_user_ns(), option);
185 if (!gid_valid(v9ses->dfltgid)) {
186 p9_debug(P9_DEBUG_ERROR,
187 "gid field, but not a gid?\n");
188 ret = -EINVAL;
189 continue;
190 }
191 break;
192 case Opt_afid:
193 r = match_int(&args[0], &option);
194 if (r < 0) {
195 p9_debug(P9_DEBUG_ERROR,
196 "integer field, but no integer?\n");
197 ret = r;
198 continue;
199 }
200 v9ses->afid = option;
201 break;
202 case Opt_uname:
203 kfree(v9ses->uname);
204 v9ses->uname = match_strdup(&args[0]);
205 if (!v9ses->uname) {
206 ret = -ENOMEM;
207 goto free_and_return;
208 }
209 break;
210 case Opt_remotename:
211 kfree(v9ses->aname);
212 v9ses->aname = match_strdup(&args[0]);
213 if (!v9ses->aname) {
214 ret = -ENOMEM;
215 goto free_and_return;
216 }
217 break;
218 case Opt_nodevmap:
219 v9ses->nodev = 1;
220 break;
221 case Opt_cache_loose:
222 v9ses->cache = CACHE_LOOSE;
223 break;
224 case Opt_fscache:
225 v9ses->cache = CACHE_FSCACHE;
226 break;
227 case Opt_mmap:
228 v9ses->cache = CACHE_MMAP;
229 break;
230 case Opt_cachetag:
231#ifdef CONFIG_9P_FSCACHE
232 v9ses->cachetag = match_strdup(&args[0]);
233#endif
234 break;
235 case Opt_cache:
236 s = match_strdup(&args[0]);
237 if (!s) {
238 ret = -ENOMEM;
239 p9_debug(P9_DEBUG_ERROR,
240 "problem allocating copy of cache arg\n");
241 goto free_and_return;
242 }
243 ret = get_cache_mode(s);
244 if (ret == -EINVAL) {
245 kfree(s);
246 goto free_and_return;
247 }
248
249 v9ses->cache = ret;
250 kfree(s);
251 break;
252
253 case Opt_access:
254 s = match_strdup(&args[0]);
255 if (!s) {
256 ret = -ENOMEM;
257 p9_debug(P9_DEBUG_ERROR,
258 "problem allocating copy of access arg\n");
259 goto free_and_return;
260 }
261
262 v9ses->flags &= ~V9FS_ACCESS_MASK;
263 if (strcmp(s, "user") == 0)
264 v9ses->flags |= V9FS_ACCESS_USER;
265 else if (strcmp(s, "any") == 0)
266 v9ses->flags |= V9FS_ACCESS_ANY;
267 else if (strcmp(s, "client") == 0) {
268 v9ses->flags |= V9FS_ACCESS_CLIENT;
269 } else {
270 uid_t uid;
271 v9ses->flags |= V9FS_ACCESS_SINGLE;
272 uid = simple_strtoul(s, &e, 10);
273 if (*e != '\0') {
274 ret = -EINVAL;
275 pr_info("Unknown access argument %s\n",
276 s);
277 kfree(s);
278 goto free_and_return;
279 }
280 v9ses->uid = make_kuid(current_user_ns(), uid);
281 if (!uid_valid(v9ses->uid)) {
282 ret = -EINVAL;
283 pr_info("Uknown uid %s\n", s);
284 kfree(s);
285 goto free_and_return;
286 }
287 }
288
289 kfree(s);
290 break;
291
292 case Opt_posixacl:
293#ifdef CONFIG_9P_FS_POSIX_ACL
294 v9ses->flags |= V9FS_POSIX_ACL;
295#else
296 p9_debug(P9_DEBUG_ERROR,
297 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
298#endif
299 break;
300
301 default:
302 continue;
303 }
304 }
305
306free_and_return:
307 kfree(tmp_options);
308fail_option_alloc:
309 return ret;
310}
311
312/**
313 * v9fs_session_init - initialize session
314 * @v9ses: session information structure
315 * @dev_name: device being mounted
316 * @data: options
317 *
318 */
319
320struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
321 const char *dev_name, char *data)
322{
323 int retval = -EINVAL;
324 struct p9_fid *fid;
325 int rc;
326
327 v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
328 if (!v9ses->uname)
329 return ERR_PTR(-ENOMEM);
330
331 v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
332 if (!v9ses->aname) {
333 kfree(v9ses->uname);
334 return ERR_PTR(-ENOMEM);
335 }
336 init_rwsem(&v9ses->rename_sem);
337
338 rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
339 if (rc) {
340 kfree(v9ses->aname);
341 kfree(v9ses->uname);
342 return ERR_PTR(rc);
343 }
344
345 spin_lock(&v9fs_sessionlist_lock);
346 list_add(&v9ses->slist, &v9fs_sessionlist);
347 spin_unlock(&v9fs_sessionlist_lock);
348
349 v9ses->uid = INVALID_UID;
350 v9ses->dfltuid = V9FS_DEFUID;
351 v9ses->dfltgid = V9FS_DEFGID;
352
353 v9ses->clnt = p9_client_create(dev_name, data);
354 if (IS_ERR(v9ses->clnt)) {
355 retval = PTR_ERR(v9ses->clnt);
356 v9ses->clnt = NULL;
357 p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
358 goto error;
359 }
360
361 v9ses->flags = V9FS_ACCESS_USER;
362
363 if (p9_is_proto_dotl(v9ses->clnt)) {
364 v9ses->flags = V9FS_ACCESS_CLIENT;
365 v9ses->flags |= V9FS_PROTO_2000L;
366 } else if (p9_is_proto_dotu(v9ses->clnt)) {
367 v9ses->flags |= V9FS_PROTO_2000U;
368 }
369
370 rc = v9fs_parse_options(v9ses, data);
371 if (rc < 0) {
372 retval = rc;
373 goto error;
374 }
375
376 v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;
377
378 if (!v9fs_proto_dotl(v9ses) &&
379 ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
380 /*
381 * We support ACCESS_CLIENT only for dotl.
382 * Fall back to ACCESS_USER
383 */
384 v9ses->flags &= ~V9FS_ACCESS_MASK;
385 v9ses->flags |= V9FS_ACCESS_USER;
386 }
387 /*FIXME !! */
388 /* for legacy mode, fall back to V9FS_ACCESS_ANY */
389 if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
390 ((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {
391
392 v9ses->flags &= ~V9FS_ACCESS_MASK;
393 v9ses->flags |= V9FS_ACCESS_ANY;
394 v9ses->uid = INVALID_UID;
395 }
396 if (!v9fs_proto_dotl(v9ses) ||
397 !((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
398 /*
399 * We support ACL checks on clinet only if the protocol is
400 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
401 */
402 v9ses->flags &= ~V9FS_ACL_MASK;
403 }
404
405 fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
406 v9ses->aname);
407 if (IS_ERR(fid)) {
408 retval = PTR_ERR(fid);
409 fid = NULL;
410 p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
411 goto error;
412 }
413
414 if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
415 fid->uid = v9ses->uid;
416 else
417 fid->uid = INVALID_UID;
418
419#ifdef CONFIG_9P_FSCACHE
420 /* register the session for caching */
421 v9fs_cache_session_get_cookie(v9ses);
422#endif
423
424 return fid;
425
426error:
427 bdi_destroy(&v9ses->bdi);
428 return ERR_PTR(retval);
429}
430
431/**
432 * v9fs_session_close - shutdown a session
433 * @v9ses: session information structure
434 *
435 */
436
437void v9fs_session_close(struct v9fs_session_info *v9ses)
438{
439 if (v9ses->clnt) {
440 p9_client_destroy(v9ses->clnt);
441 v9ses->clnt = NULL;
442 }
443
444#ifdef CONFIG_9P_FSCACHE
445 if (v9ses->fscache) {
446 v9fs_cache_session_put_cookie(v9ses);
447 kfree(v9ses->cachetag);
448 }
449#endif
450 kfree(v9ses->uname);
451 kfree(v9ses->aname);
452
453 bdi_destroy(&v9ses->bdi);
454
455 spin_lock(&v9fs_sessionlist_lock);
456 list_del(&v9ses->slist);
457 spin_unlock(&v9fs_sessionlist_lock);
458}
459
460/**
461 * v9fs_session_cancel - terminate a session
462 * @v9ses: session to terminate
463 *
464 * mark transport as disconnected and cancel all pending requests.
465 */
466
467void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
468 p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
469 p9_client_disconnect(v9ses->clnt);
470}
471
472/**
473 * v9fs_session_begin_cancel - Begin terminate of a session
474 * @v9ses: session to terminate
475 *
476 * After this call we don't allow any request other than clunk.
477 */
478
479void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
480{
481 p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
482 p9_client_begin_disconnect(v9ses->clnt);
483}
484
485extern int v9fs_error_init(void);
486
487static struct kobject *v9fs_kobj;
488
489#ifdef CONFIG_9P_FSCACHE
490/**
491 * caches_show - list caches associated with a session
492 *
493 * Returns the size of buffer written.
494 */
495
496static ssize_t caches_show(struct kobject *kobj,
497 struct kobj_attribute *attr,
498 char *buf)
499{
500 ssize_t n = 0, count = 0, limit = PAGE_SIZE;
501 struct v9fs_session_info *v9ses;
502
503 spin_lock(&v9fs_sessionlist_lock);
504 list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
505 if (v9ses->cachetag) {
506 n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
507 if (n < 0) {
508 count = n;
509 break;
510 }
511
512 count += n;
513 limit -= n;
514 }
515 }
516
517 spin_unlock(&v9fs_sessionlist_lock);
518 return count;
519}
520
521static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
522#endif /* CONFIG_9P_FSCACHE */
523
524static struct attribute *v9fs_attrs[] = {
525#ifdef CONFIG_9P_FSCACHE
526 &v9fs_attr_cache.attr,
527#endif
528 NULL,
529};
530
531static struct attribute_group v9fs_attr_group = {
532 .attrs = v9fs_attrs,
533};
534
535/**
536 * v9fs_sysfs_init - Initialize the v9fs sysfs interface
537 *
538 */
539
540static int v9fs_sysfs_init(void)
541{
542 v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
543 if (!v9fs_kobj)
544 return -ENOMEM;
545
546 if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
547 kobject_put(v9fs_kobj);
548 return -ENOMEM;
549 }
550
551 return 0;
552}
553
554/**
555 * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
556 *
557 */
558
559static void v9fs_sysfs_cleanup(void)
560{
561 sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
562 kobject_put(v9fs_kobj);
563}
564
565static void v9fs_inode_init_once(void *foo)
566{
567 struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
568#ifdef CONFIG_9P_FSCACHE
569 v9inode->fscache = NULL;
570#endif
571 memset(&v9inode->qid, 0, sizeof(v9inode->qid));
572 inode_init_once(&v9inode->vfs_inode);
573}
574
575/**
576 * v9fs_init_inode_cache - initialize a cache for 9P
577 * Returns 0 on success.
578 */
579static int v9fs_init_inode_cache(void)
580{
581 v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
582 sizeof(struct v9fs_inode),
583 0, (SLAB_RECLAIM_ACCOUNT|
584 SLAB_MEM_SPREAD),
585 v9fs_inode_init_once);
586 if (!v9fs_inode_cache)
587 return -ENOMEM;
588
589 return 0;
590}
591
592/**
593 * v9fs_destroy_inode_cache - destroy the cache of 9P inode
594 *
595 */
596static void v9fs_destroy_inode_cache(void)
597{
598 /*
599 * Make sure all delayed rcu free inodes are flushed before we
600 * destroy cache.
601 */
602 rcu_barrier();
603 kmem_cache_destroy(v9fs_inode_cache);
604}
605
606static int v9fs_cache_register(void)
607{
608 int ret;
609 ret = v9fs_init_inode_cache();
610 if (ret < 0)
611 return ret;
612#ifdef CONFIG_9P_FSCACHE
613 ret = fscache_register_netfs(&v9fs_cache_netfs);
614 if (ret < 0)
615 v9fs_destroy_inode_cache();
616#endif
617 return ret;
618}
619
620static void v9fs_cache_unregister(void)
621{
622 v9fs_destroy_inode_cache();
623#ifdef CONFIG_9P_FSCACHE
624 fscache_unregister_netfs(&v9fs_cache_netfs);
625#endif
626}
627
628/**
629 * init_v9fs - Initialize module
630 *
631 */
632
633static int __init init_v9fs(void)
634{
635 int err;
636 pr_info("Installing v9fs 9p2000 file system support\n");
637 /* TODO: Setup list of registered trasnport modules */
638
639 err = v9fs_cache_register();
640 if (err < 0) {
641 pr_err("Failed to register v9fs for caching\n");
642 return err;
643 }
644
645 err = v9fs_sysfs_init();
646 if (err < 0) {
647 pr_err("Failed to register with sysfs\n");
648 goto out_cache;
649 }
650 err = register_filesystem(&v9fs_fs_type);
651 if (err < 0) {
652 pr_err("Failed to register filesystem\n");
653 goto out_sysfs_cleanup;
654 }
655
656 return 0;
657
658out_sysfs_cleanup:
659 v9fs_sysfs_cleanup();
660
661out_cache:
662 v9fs_cache_unregister();
663
664 return err;
665}
666
667/**
668 * exit_v9fs - shutdown module
669 *
670 */
671
672static void __exit exit_v9fs(void)
673{
674 v9fs_sysfs_cleanup();
675 v9fs_cache_unregister();
676 unregister_filesystem(&v9fs_fs_type);
677}
678
679module_init(init_v9fs)
680module_exit(exit_v9fs)
681
682MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
683MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
684MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
685MODULE_LICENSE("GPL");