summaryrefslogtreecommitdiffstats
path: root/fs/9p/v9fs.c
blob: 14da82564f4eef3e271c2cf891582dac45190ece (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
/*
 *  linux/fs/9p/v9fs.c
 *
 *  This file contains functions assisting in mapping VFS to 9P2000
 *
 *  Copyright (C) 2004-2008 by Eric Van Hensbergen <ericvh@gmail.com>
 *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to:
 *  Free Software Foundation
 *  51 Franklin Street, Fifth Floor
 *  Boston, MA  02111-1301  USA
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/parser.h>
#include <linux/idr.h>
#include <linux/slab.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <net/9p/transport.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "cache.h"

static DEFINE_SPINLOCK(v9fs_sessionlist_lock);
static LIST_HEAD(v9fs_sessionlist);
struct kmem_cache *v9fs_inode_cache;

/*
 * Option Parsing (code inspired by NFS code)
 *  NOTE: each transport will parse its own options
 */

enum {
	/* Options that take integer arguments */
	Opt_debug, Opt_dfltuid, Opt_dfltgid, Opt_afid,
	/* String options */
	Opt_uname, Opt_remotename, Opt_trans, Opt_cache, Opt_cachetag,
	/* Options that take no arguments */
	Opt_nodevmap,
	/* Cache options */
	Opt_cache_loose, Opt_fscache, Opt_mmap,
	/* Access options */
	Opt_access, Opt_posixacl,
	/* Error token */
	Opt_err
};

static const match_table_t tokens = {
	{Opt_debug, "debug=%x"},
	{Opt_dfltuid, "dfltuid=%u"},
	{Opt_dfltgid, "dfltgid=%u"},
	{Opt_afid, "afid=%u"},
	{Opt_uname, "uname=%s"},
	{Opt_remotename, "aname=%s"},
	{Opt_nodevmap, "nodevmap"},
	{Opt_cache, "cache=%s"},
	{Opt_cache_loose, "loose"},
	{Opt_fscache, "fscache"},
	{Opt_mmap, "mmap"},
	{Opt_cachetag, "cachetag=%s"},
	{Opt_access, "access=%s"},
	{Opt_posixacl, "posixacl"},
	{Opt_err, NULL}
};

/* Interpret mount options for cache mode */
static int get_cache_mode(char *s)
{
	int version = -EINVAL;

	if (!strcmp(s, "loose")) {
		version = CACHE_LOOSE;
		p9_debug(P9_DEBUG_9P, "Cache mode: loose\n");
	} else if (!strcmp(s, "fscache")) {
		version = CACHE_FSCACHE;
		p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
	} else if (!strcmp(s, "mmap")) {
		version = CACHE_MMAP;
		p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
	} else if (!strcmp(s, "none")) {
		version = CACHE_NONE;
		p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
	} else
		pr_info("Unknown Cache mode %s\n", s);
	return version;
}

/**
 * v9fs_parse_options - parse mount options into session structure
 * @v9ses: existing v9fs session information
 *
 * Return 0 upon success, -ERRNO upon failure.
 */

static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
{
	char *options, *tmp_options;
	substring_t args[MAX_OPT_ARGS];
	char *p;
	int option = 0;
	char *s, *e;
	int ret = 0;

	/* setup defaults */
	v9ses->afid = ~0;
	v9ses->debug = 0;
	v9ses->cache = CACHE_NONE;
#ifdef CONFIG_9P_FSCACHE
	v9ses->cachetag = NULL;
#endif

	if (!opts)
		return 0;

	tmp_options = kstrdup(opts, GFP_KERNEL);
	if (!tmp_options) {
		ret = -ENOMEM;
		goto fail_option_alloc;
	}
	options = tmp_options;

	while ((p = strsep(&options, ",")) != NULL) {
		int token, r;
		if (!*p)
			continue;
		token = match_token(p, tokens, args);
		switch (token) {
		case Opt_debug:
			r = match_int(&args[0], &option);
			if (r < 0) {
				p9_debug(P9_DEBUG_ERROR,
					 "integer field, but no integer?\n");
				ret = r;
				continue;
			}
			v9ses->debug = option;
#ifdef CONFIG_NET_9P_DEBUG
			p9_debug_level = option;
#endif
			break;

		case Opt_dfltuid:
			r = match_int(&args[0], &option);
			if (r < 0) {
				p9_debug(P9_DEBUG_ERROR,
					 "integer field, but no integer?\n");
				ret = r;
				continue;
			}
			v9ses->dfltuid = make_kuid(current_user_ns(), option);
			if (!uid_valid(v9ses->dfltuid)) {
				p9_debug(P9_DEBUG_ERROR,
					 "uid field, but not a uid?\n");
				ret = -EINVAL;
				continue;
			}
			break;
		case Opt_dfltgid:
			r = match_int(&args[0], &option);
			if (r < 0) {
				p9_debug(P9_DEBUG_ERROR,
					 "integer field, but no integer?\n");
				ret = r;
				continue;
			}
			v9ses->dfltgid = make_kgid(current_user_ns(), option);
			if (!gid_valid(v9ses->dfltgid)) {
				p9_debug(P9_DEBUG_ERROR,
					 "gid field, but not a gid?\n");
				ret = -EINVAL;
				continue;
			}
			break;
		case Opt_afid:
			r = match_int(&args[0], &option);
			if (r < 0) {
				p9_debug(P9_DEBUG_ERROR,
					 "integer field, but no integer?\n");
				ret = r;
				continue;
			}
			v9ses->afid = option;
			break;
		case Opt_uname:
			kfree(v9ses->uname);
			v9ses->uname = match_strdup(&args[0]);
			if (!v9ses->uname) {
				ret = -ENOMEM;
				goto free_and_return;
			}
			break;
		case Opt_remotename:
			kfree(v9ses->aname);
			v9ses->aname = match_strdup(&args[0]);
			if (!v9ses->aname) {
				ret = -ENOMEM;
				goto free_and_return;
			}
			break;
		case Opt_nodevmap:
			v9ses->nodev = 1;
			break;
		case Opt_cache_loose:
			v9ses->cache = CACHE_LOOSE;
			break;
		case Opt_fscache:
			v9ses->cache = CACHE_FSCACHE;
			break;
		case Opt_mmap:
			v9ses->cache = CACHE_MMAP;
			break;
		case Opt_cachetag:
#ifdef CONFIG_9P_FSCACHE
			v9ses->cachetag = match_strdup(&args[0]);
#endif
			break;
		case Opt_cache:
			s = match_strdup(&args[0]);
			if (!s) {
				ret = -ENOMEM;
				p9_debug(P9_DEBUG_ERROR,
					 "problem allocating copy of cache arg\n");
				goto free_and_return;
			}
			ret = get_cache_mode(s);
			if (ret == -EINVAL) {
				kfree(s);
				goto free_and_return;
			}

			v9ses->cache = ret;
			kfree(s);
			break;

		case Opt_access:
			s = match_strdup(&args[0]);
			if (!s) {
				ret = -ENOMEM;
				p9_debug(P9_DEBUG_ERROR,
					 "problem allocating copy of access arg\n");
				goto free_and_return;
			}

			v9ses->flags &= ~V9FS_ACCESS_MASK;
			if (strcmp(s, "user") == 0)
				v9ses->flags |= V9FS_ACCESS_USER;
			else if (strcmp(s, "any") == 0)
				v9ses->flags |= V9FS_ACCESS_ANY;
			else if (strcmp(s, "client") == 0) {
				v9ses->flags |= V9FS_ACCESS_CLIENT;
			} else {
				uid_t uid;
				v9ses->flags |= V9FS_ACCESS_SINGLE;
				uid = simple_strtoul(s, &e, 10);
				if (*e != '\0') {
					ret = -EINVAL;
					pr_info("Unknown access argument %s\n",
						s);
					kfree(s);
					goto free_and_return;
				}
				v9ses->uid = make_kuid(current_user_ns(), uid);
				if (!uid_valid(v9ses->uid)) {
					ret = -EINVAL;
					pr_info("Uknown uid %s\n", s);
					kfree(s);
					goto free_and_return;
				}
			}

			kfree(s);
			break;

		case Opt_posixacl:
#ifdef CONFIG_9P_FS_POSIX_ACL
			v9ses->flags |= V9FS_POSIX_ACL;
#else
			p9_debug(P9_DEBUG_ERROR,
				 "Not defined CONFIG_9P_FS_POSIX_ACL. Ignoring posixacl option\n");
#endif
			break;

		default:
			continue;
		}
	}

free_and_return:
	kfree(tmp_options);
fail_option_alloc:
	return ret;
}

/**
 * v9fs_session_init - initialize session
 * @v9ses: session information structure
 * @dev_name: device being mounted
 * @data: options
 *
 */

struct p9_fid *v9fs_session_init(struct v9fs_session_info *v9ses,
		  const char *dev_name, char *data)
{
	int retval = -EINVAL;
	struct p9_fid *fid;
	int rc;

	v9ses->uname = kstrdup(V9FS_DEFUSER, GFP_KERNEL);
	if (!v9ses->uname)
		return ERR_PTR(-ENOMEM);

	v9ses->aname = kstrdup(V9FS_DEFANAME, GFP_KERNEL);
	if (!v9ses->aname) {
		kfree(v9ses->uname);
		return ERR_PTR(-ENOMEM);
	}
	init_rwsem(&v9ses->rename_sem);

	rc = bdi_setup_and_register(&v9ses->bdi, "9p", BDI_CAP_MAP_COPY);
	if (rc) {
		kfree(v9ses->aname);
		kfree(v9ses->uname);
		return ERR_PTR(rc);
	}

	spin_lock(&v9fs_sessionlist_lock);
	list_add(&v9ses->slist, &v9fs_sessionlist);
	spin_unlock(&v9fs_sessionlist_lock);

	v9ses->uid = INVALID_UID;
	v9ses->dfltuid = V9FS_DEFUID;
	v9ses->dfltgid = V9FS_DEFGID;

	v9ses->clnt = p9_client_create(dev_name, data);
	if (IS_ERR(v9ses->clnt)) {
		retval = PTR_ERR(v9ses->clnt);
		v9ses->clnt = NULL;
		p9_debug(P9_DEBUG_ERROR, "problem initializing 9p client\n");
		goto error;
	}

	v9ses->flags = V9FS_ACCESS_USER;

	if (p9_is_proto_dotl(v9ses->clnt)) {
		v9ses->flags = V9FS_ACCESS_CLIENT;
		v9ses->flags |= V9FS_PROTO_2000L;
	} else if (p9_is_proto_dotu(v9ses->clnt)) {
		v9ses->flags |= V9FS_PROTO_2000U;
	}

	rc = v9fs_parse_options(v9ses, data);
	if (rc < 0) {
		retval = rc;
		goto error;
	}

	v9ses->maxdata = v9ses->clnt->msize - P9_IOHDRSZ;

	if (!v9fs_proto_dotl(v9ses) &&
	    ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
		/*
		 * We support ACCESS_CLIENT only for dotl.
		 * Fall back to ACCESS_USER
		 */
		v9ses->flags &= ~V9FS_ACCESS_MASK;
		v9ses->flags |= V9FS_ACCESS_USER;
	}
	/*FIXME !! */
	/* for legacy mode, fall back to V9FS_ACCESS_ANY */
	if (!(v9fs_proto_dotu(v9ses) || v9fs_proto_dotl(v9ses)) &&
		((v9ses->flags&V9FS_ACCESS_MASK) == V9FS_ACCESS_USER)) {

		v9ses->flags &= ~V9FS_ACCESS_MASK;
		v9ses->flags |= V9FS_ACCESS_ANY;
		v9ses->uid = INVALID_UID;
	}
	if (!v9fs_proto_dotl(v9ses) ||
		!((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_CLIENT)) {
		/*
		 * We support ACL checks on clinet only if the protocol is
		 * 9P2000.L and access is V9FS_ACCESS_CLIENT.
		 */
		v9ses->flags &= ~V9FS_ACL_MASK;
	}

	fid = p9_client_attach(v9ses->clnt, NULL, v9ses->uname, INVALID_UID,
							v9ses->aname);
	if (IS_ERR(fid)) {
		retval = PTR_ERR(fid);
		fid = NULL;
		p9_debug(P9_DEBUG_ERROR, "cannot attach\n");
		goto error;
	}

	if ((v9ses->flags & V9FS_ACCESS_MASK) == V9FS_ACCESS_SINGLE)
		fid->uid = v9ses->uid;
	else
		fid->uid = INVALID_UID;

#ifdef CONFIG_9P_FSCACHE
	/* register the session for caching */
	v9fs_cache_session_get_cookie(v9ses);
#endif

	return fid;

error:
	bdi_destroy(&v9ses->bdi);
	return ERR_PTR(retval);
}

/**
 * v9fs_session_close - shutdown a session
 * @v9ses: session information structure
 *
 */

void v9fs_session_close(struct v9fs_session_info *v9ses)
{
	if (v9ses->clnt) {
		p9_client_destroy(v9ses->clnt);
		v9ses->clnt = NULL;
	}

#ifdef CONFIG_9P_FSCACHE
	if (v9ses->fscache) {
		v9fs_cache_session_put_cookie(v9ses);
		kfree(v9ses->cachetag);
	}
#endif
	kfree(v9ses->uname);
	kfree(v9ses->aname);

	bdi_destroy(&v9ses->bdi);

	spin_lock(&v9fs_sessionlist_lock);
	list_del(&v9ses->slist);
	spin_unlock(&v9fs_sessionlist_lock);
}

/**
 * v9fs_session_cancel - terminate a session
 * @v9ses: session to terminate
 *
 * mark transport as disconnected and cancel all pending requests.
 */

void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
	p9_debug(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
	p9_client_disconnect(v9ses->clnt);
}

/**
 * v9fs_session_begin_cancel - Begin terminate of a session
 * @v9ses: session to terminate
 *
 * After this call we don't allow any request other than clunk.
 */

void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
{
	p9_debug(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
	p9_client_begin_disconnect(v9ses->clnt);
}

extern int v9fs_error_init(void);

static struct kobject *v9fs_kobj;

#ifdef CONFIG_9P_FSCACHE
/**
 * caches_show - list caches associated with a session
 *
 * Returns the size of buffer written.
 */

static ssize_t caches_show(struct kobject *kobj,
			   struct kobj_attribute *attr,
			   char *buf)
{
	ssize_t n = 0, count = 0, limit = PAGE_SIZE;
	struct v9fs_session_info *v9ses;

	spin_lock(&v9fs_sessionlist_lock);
	list_for_each_entry(v9ses, &v9fs_sessionlist, slist) {
		if (v9ses->cachetag) {
			n = snprintf(buf, limit, "%s\n", v9ses->cachetag);
			if (n < 0) {
				count = n;
				break;
			}

			count += n;
			limit -= n;
		}
	}

	spin_unlock(&v9fs_sessionlist_lock);
	return count;
}

static struct kobj_attribute v9fs_attr_cache = __ATTR_RO(caches);
#endif /* CONFIG_9P_FSCACHE */

static struct attribute *v9fs_attrs[] = {
#ifdef CONFIG_9P_FSCACHE
	&v9fs_attr_cache.attr,
#endif
	NULL,
};

static struct attribute_group v9fs_attr_group = {
	.attrs = v9fs_attrs,
};

/**
 * v9fs_sysfs_init - Initialize the v9fs sysfs interface
 *
 */

static int v9fs_sysfs_init(void)
{
	v9fs_kobj = kobject_create_and_add("9p", fs_kobj);
	if (!v9fs_kobj)
		return -ENOMEM;

	if (sysfs_create_group(v9fs_kobj, &v9fs_attr_group)) {
		kobject_put(v9fs_kobj);
		return -ENOMEM;
	}

	return 0;
}

/**
 * v9fs_sysfs_cleanup - Unregister the v9fs sysfs interface
 *
 */

static void v9fs_sysfs_cleanup(void)
{
	sysfs_remove_group(v9fs_kobj, &v9fs_attr_group);
	kobject_put(v9fs_kobj);
}

static void v9fs_inode_init_once(void *foo)
{
	struct v9fs_inode *v9inode = (struct v9fs_inode *)foo;
#ifdef CONFIG_9P_FSCACHE
	v9inode->fscache = NULL;
#endif
	memset(&v9inode->qid, 0, sizeof(v9inode->qid));
	inode_init_once(&v9inode->vfs_inode);
}

/**
 * v9fs_init_inode_cache - initialize a cache for 9P
 * Returns 0 on success.
 */
static int v9fs_init_inode_cache(void)
{
	v9fs_inode_cache = kmem_cache_create("v9fs_inode_cache",
					  sizeof(struct v9fs_inode),
					  0, (SLAB_RECLAIM_ACCOUNT|
					      SLAB_MEM_SPREAD),
					  v9fs_inode_init_once);
	if (!v9fs_inode_cache)
		return -ENOMEM;

	return 0;
}

/**
 * v9fs_destroy_inode_cache - destroy the cache of 9P inode
 *
 */
static void v9fs_destroy_inode_cache(void)
{
	/*
	 * Make sure all delayed rcu free inodes are flushed before we
	 * destroy cache.
	 */
	rcu_barrier();
	kmem_cache_destroy(v9fs_inode_cache);
}

static int v9fs_cache_register(void)
{
	int ret;
	ret = v9fs_init_inode_cache();
	if (ret < 0)
		return ret;
#ifdef CONFIG_9P_FSCACHE
	ret = fscache_register_netfs(&v9fs_cache_netfs);
	if (ret < 0)
		v9fs_destroy_inode_cache();
#endif
	return ret;
}

static void v9fs_cache_unregister(void)
{
	v9fs_destroy_inode_cache();
#ifdef CONFIG_9P_FSCACHE
	fscache_unregister_netfs(&v9fs_cache_netfs);
#endif
}

/**
 * init_v9fs - Initialize module
 *
 */

static int __init init_v9fs(void)
{
	int err;
	pr_info("Installing v9fs 9p2000 file system support\n");
	/* TODO: Setup list of registered trasnport modules */

	err = v9fs_cache_register();
	if (err < 0) {
		pr_err("Failed to register v9fs for caching\n");
		return err;
	}

	err = v9fs_sysfs_init();
	if (err < 0) {
		pr_err("Failed to register with sysfs\n");
		goto out_cache;
	}
	err = register_filesystem(&v9fs_fs_type);
	if (err < 0) {
		pr_err("Failed to register filesystem\n");
		goto out_sysfs_cleanup;
	}

	return 0;

out_sysfs_cleanup:
	v9fs_sysfs_cleanup();

out_cache:
	v9fs_cache_unregister();

	return err;
}

/**
 * exit_v9fs - shutdown module
 *
 */

static void __exit exit_v9fs(void)
{
	v9fs_sysfs_cleanup();
	v9fs_cache_unregister();
	unregister_filesystem(&v9fs_fs_type);
}

module_init(init_v9fs)
module_exit(exit_v9fs)

MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
MODULE_AUTHOR("Ron Minnich <rminnich@lanl.gov>");
MODULE_LICENSE("GPL");