1 /* AFS superblock handling
2 *
3 * Copyright (c) 2002, 2007 Red Hat, Inc. All rights reserved.
4 *
5 * This software may be freely redistributed under the terms of the
6 * GNU General Public License.
7 *
8 * You should have received a copy of the GNU General Public License
9 * along with this program; if not, write to the Free Software
10 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
11 *
12 * Authors: David Howells <dhowells@redhat.com>
13 * David Woodhouse <dwmw2@infradead.org>
14 *
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/mount.h>
20 #include <linux/init.h>
21 #include <linux/slab.h>
22 #include <linux/fs.h>
23 #include <linux/pagemap.h>
24 #include <linux/parser.h>
25 #include <linux/statfs.h>
26 #include <linux/sched.h>
27 #include <linux/nsproxy.h>
28 #include <linux/magic.h>
29 #include <net/net_namespace.h>
30 #include "internal.h"
31
32 static void afs_i_init_once(void *foo);
33 static struct dentry *afs_mount(struct file_system_type *fs_type,
34 int flags, const char *dev_name, void *data);
35 static void afs_kill_super(struct super_block *sb);
36 static struct inode *afs_alloc_inode(struct super_block *sb);
37 static void afs_destroy_inode(struct inode *inode);
38 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
39 static int afs_show_devname(struct seq_file *m, struct dentry *root);
40 static int afs_show_options(struct seq_file *m, struct dentry *root);
41
42 struct file_system_type afs_fs_type = {
43 .owner = THIS_MODULE,
44 .name = "afs",
45 .mount = afs_mount,
46 .kill_sb = afs_kill_super,
47 .fs_flags = 0,
48 };
49 MODULE_ALIAS_FS("afs");
50
51 int afs_net_id;
52
53 static const struct super_operations afs_super_ops = {
54 .statfs = afs_statfs,
55 .alloc_inode = afs_alloc_inode,
56 .drop_inode = afs_drop_inode,
57 .destroy_inode = afs_destroy_inode,
58 .evict_inode = afs_evict_inode,
59 .show_devname = afs_show_devname,
60 .show_options = afs_show_options,
61 };
62
63 static struct kmem_cache *afs_inode_cachep;
64 static atomic_t afs_count_active_inodes;
65
66 enum {
67 afs_no_opt,
68 afs_opt_cell,
69 afs_opt_dyn,
70 afs_opt_rwpath,
71 afs_opt_vol,
72 afs_opt_autocell,
73 };
74
75 static const match_table_t afs_options_list = {
76 { afs_opt_cell, "cell=%s" },
77 { afs_opt_dyn, "dyn" },
78 { afs_opt_rwpath, "rwpath" },
79 { afs_opt_vol, "vol=%s" },
80 { afs_opt_autocell, "autocell" },
81 { afs_no_opt, NULL },
82 };
83
84 /*
85 * initialise the filesystem
86 */
afs_fs_init(void)87 int __init afs_fs_init(void)
88 {
89 int ret;
90
91 _enter("");
92
93 /* create ourselves an inode cache */
94 atomic_set(&afs_count_active_inodes, 0);
95
96 ret = -ENOMEM;
97 afs_inode_cachep = kmem_cache_create("afs_inode_cache",
98 sizeof(struct afs_vnode),
99 0,
100 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
101 afs_i_init_once);
102 if (!afs_inode_cachep) {
103 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
104 return ret;
105 }
106
107 /* now export our filesystem to lesser mortals */
108 ret = register_filesystem(&afs_fs_type);
109 if (ret < 0) {
110 kmem_cache_destroy(afs_inode_cachep);
111 _leave(" = %d", ret);
112 return ret;
113 }
114
115 _leave(" = 0");
116 return 0;
117 }
118
119 /*
120 * clean up the filesystem
121 */
afs_fs_exit(void)122 void afs_fs_exit(void)
123 {
124 _enter("");
125
126 afs_mntpt_kill_timer();
127 unregister_filesystem(&afs_fs_type);
128
129 if (atomic_read(&afs_count_active_inodes) != 0) {
130 printk("kAFS: %d active inode objects still present\n",
131 atomic_read(&afs_count_active_inodes));
132 BUG();
133 }
134
135 /*
136 * Make sure all delayed rcu free inodes are flushed before we
137 * destroy cache.
138 */
139 rcu_barrier();
140 kmem_cache_destroy(afs_inode_cachep);
141 _leave("");
142 }
143
144 /*
145 * Display the mount device name in /proc/mounts.
146 */
afs_show_devname(struct seq_file * m,struct dentry * root)147 static int afs_show_devname(struct seq_file *m, struct dentry *root)
148 {
149 struct afs_super_info *as = AFS_FS_S(root->d_sb);
150 struct afs_volume *volume = as->volume;
151 struct afs_cell *cell = as->cell;
152 const char *suf = "";
153 char pref = '%';
154
155 if (as->dyn_root) {
156 seq_puts(m, "none");
157 return 0;
158 }
159
160 switch (volume->type) {
161 case AFSVL_RWVOL:
162 break;
163 case AFSVL_ROVOL:
164 pref = '#';
165 if (volume->type_force)
166 suf = ".readonly";
167 break;
168 case AFSVL_BACKVOL:
169 pref = '#';
170 suf = ".backup";
171 break;
172 }
173
174 seq_printf(m, "%c%s:%s%s", pref, cell->name, volume->name, suf);
175 return 0;
176 }
177
178 /*
179 * Display the mount options in /proc/mounts.
180 */
afs_show_options(struct seq_file * m,struct dentry * root)181 static int afs_show_options(struct seq_file *m, struct dentry *root)
182 {
183 struct afs_super_info *as = AFS_FS_S(root->d_sb);
184
185 if (as->dyn_root)
186 seq_puts(m, ",dyn");
187 if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
188 seq_puts(m, ",autocell");
189 return 0;
190 }
191
192 /*
193 * parse the mount options
194 * - this function has been shamelessly adapted from the ext3 fs which
195 * shamelessly adapted it from the msdos fs
196 */
afs_parse_options(struct afs_mount_params * params,char * options,const char ** devname)197 static int afs_parse_options(struct afs_mount_params *params,
198 char *options, const char **devname)
199 {
200 struct afs_cell *cell;
201 substring_t args[MAX_OPT_ARGS];
202 char *p;
203 int token;
204
205 _enter("%s", options);
206
207 options[PAGE_SIZE - 1] = 0;
208
209 while ((p = strsep(&options, ","))) {
210 if (!*p)
211 continue;
212
213 token = match_token(p, afs_options_list, args);
214 switch (token) {
215 case afs_opt_cell:
216 rcu_read_lock();
217 cell = afs_lookup_cell_rcu(params->net,
218 args[0].from,
219 args[0].to - args[0].from);
220 rcu_read_unlock();
221 if (IS_ERR(cell))
222 return PTR_ERR(cell);
223 afs_put_cell(params->net, params->cell);
224 params->cell = cell;
225 break;
226
227 case afs_opt_rwpath:
228 params->rwpath = true;
229 break;
230
231 case afs_opt_vol:
232 *devname = args[0].from;
233 break;
234
235 case afs_opt_autocell:
236 params->autocell = true;
237 break;
238
239 case afs_opt_dyn:
240 params->dyn_root = true;
241 break;
242
243 default:
244 printk(KERN_ERR "kAFS:"
245 " Unknown or invalid mount option: '%s'\n", p);
246 return -EINVAL;
247 }
248 }
249
250 _leave(" = 0");
251 return 0;
252 }
253
254 /*
255 * parse a device name to get cell name, volume name, volume type and R/W
256 * selector
257 * - this can be one of the following:
258 * "%[cell:]volume[.]" R/W volume
259 * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0),
260 * or R/W (rwpath=1) volume
261 * "%[cell:]volume.readonly" R/O volume
262 * "#[cell:]volume.readonly" R/O volume
263 * "%[cell:]volume.backup" Backup volume
264 * "#[cell:]volume.backup" Backup volume
265 */
afs_parse_device_name(struct afs_mount_params * params,const char * name)266 static int afs_parse_device_name(struct afs_mount_params *params,
267 const char *name)
268 {
269 struct afs_cell *cell;
270 const char *cellname, *suffix;
271 int cellnamesz;
272
273 _enter(",%s", name);
274
275 if (!name) {
276 printk(KERN_ERR "kAFS: no volume name specified\n");
277 return -EINVAL;
278 }
279
280 if ((name[0] != '%' && name[0] != '#') || !name[1]) {
281 printk(KERN_ERR "kAFS: unparsable volume name\n");
282 return -EINVAL;
283 }
284
285 /* determine the type of volume we're looking for */
286 params->type = AFSVL_ROVOL;
287 params->force = false;
288 if (params->rwpath || name[0] == '%') {
289 params->type = AFSVL_RWVOL;
290 params->force = true;
291 }
292 name++;
293
294 /* split the cell name out if there is one */
295 params->volname = strchr(name, ':');
296 if (params->volname) {
297 cellname = name;
298 cellnamesz = params->volname - name;
299 params->volname++;
300 } else {
301 params->volname = name;
302 cellname = NULL;
303 cellnamesz = 0;
304 }
305
306 /* the volume type is further affected by a possible suffix */
307 suffix = strrchr(params->volname, '.');
308 if (suffix) {
309 if (strcmp(suffix, ".readonly") == 0) {
310 params->type = AFSVL_ROVOL;
311 params->force = true;
312 } else if (strcmp(suffix, ".backup") == 0) {
313 params->type = AFSVL_BACKVOL;
314 params->force = true;
315 } else if (suffix[1] == 0) {
316 } else {
317 suffix = NULL;
318 }
319 }
320
321 params->volnamesz = suffix ?
322 suffix - params->volname : strlen(params->volname);
323
324 _debug("cell %*.*s [%p]",
325 cellnamesz, cellnamesz, cellname ?: "", params->cell);
326
327 /* lookup the cell record */
328 if (cellname || !params->cell) {
329 cell = afs_lookup_cell(params->net, cellname, cellnamesz,
330 NULL, false);
331 if (IS_ERR(cell)) {
332 printk(KERN_ERR "kAFS: unable to lookup cell '%*.*s'\n",
333 cellnamesz, cellnamesz, cellname ?: "");
334 return PTR_ERR(cell);
335 }
336 afs_put_cell(params->net, params->cell);
337 params->cell = cell;
338 }
339
340 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
341 params->cell->name, params->cell,
342 params->volnamesz, params->volnamesz, params->volname,
343 suffix ?: "-", params->type, params->force ? " FORCE" : "");
344
345 return 0;
346 }
347
348 /*
349 * check a superblock to see if it's the one we're looking for
350 */
afs_test_super(struct super_block * sb,void * data)351 static int afs_test_super(struct super_block *sb, void *data)
352 {
353 struct afs_super_info *as1 = data;
354 struct afs_super_info *as = AFS_FS_S(sb);
355
356 return (as->net_ns == as1->net_ns &&
357 as->volume &&
358 as->volume->vid == as1->volume->vid &&
359 as->cell == as1->cell &&
360 !as->dyn_root);
361 }
362
afs_dynroot_test_super(struct super_block * sb,void * data)363 static int afs_dynroot_test_super(struct super_block *sb, void *data)
364 {
365 struct afs_super_info *as1 = data;
366 struct afs_super_info *as = AFS_FS_S(sb);
367
368 return (as->net_ns == as1->net_ns &&
369 as->dyn_root);
370 }
371
afs_set_super(struct super_block * sb,void * data)372 static int afs_set_super(struct super_block *sb, void *data)
373 {
374 struct afs_super_info *as = data;
375
376 sb->s_fs_info = as;
377 return set_anon_super(sb, NULL);
378 }
379
380 /*
381 * fill in the superblock
382 */
afs_fill_super(struct super_block * sb,struct afs_mount_params * params)383 static int afs_fill_super(struct super_block *sb,
384 struct afs_mount_params *params)
385 {
386 struct afs_super_info *as = AFS_FS_S(sb);
387 struct afs_fid fid;
388 struct inode *inode = NULL;
389 int ret;
390
391 _enter("");
392
393 /* fill in the superblock */
394 sb->s_blocksize = PAGE_SIZE;
395 sb->s_blocksize_bits = PAGE_SHIFT;
396 sb->s_maxbytes = MAX_LFS_FILESIZE;
397 sb->s_magic = AFS_FS_MAGIC;
398 sb->s_op = &afs_super_ops;
399 if (!as->dyn_root)
400 sb->s_xattr = afs_xattr_handlers;
401 ret = super_setup_bdi(sb);
402 if (ret)
403 return ret;
404 sb->s_bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_SIZE;
405
406 /* allocate the root inode and dentry */
407 if (as->dyn_root) {
408 inode = afs_iget_pseudo_dir(sb, true);
409 } else {
410 sprintf(sb->s_id, "%u", as->volume->vid);
411 afs_activate_volume(as->volume);
412 fid.vid = as->volume->vid;
413 fid.vnode = 1;
414 fid.unique = 1;
415 inode = afs_iget(sb, params->key, &fid, NULL, NULL, NULL);
416 }
417
418 if (IS_ERR(inode))
419 return PTR_ERR(inode);
420
421 if (params->autocell || params->dyn_root)
422 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
423
424 ret = -ENOMEM;
425 sb->s_root = d_make_root(inode);
426 if (!sb->s_root)
427 goto error;
428
429 if (as->dyn_root) {
430 sb->s_d_op = &afs_dynroot_dentry_operations;
431 ret = afs_dynroot_populate(sb);
432 if (ret < 0)
433 goto error;
434 } else {
435 sb->s_d_op = &afs_fs_dentry_operations;
436 }
437
438 _leave(" = 0");
439 return 0;
440
441 error:
442 _leave(" = %d", ret);
443 return ret;
444 }
445
afs_alloc_sbi(struct afs_mount_params * params)446 static struct afs_super_info *afs_alloc_sbi(struct afs_mount_params *params)
447 {
448 struct afs_super_info *as;
449
450 as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
451 if (as) {
452 as->net_ns = get_net(params->net_ns);
453 if (params->dyn_root)
454 as->dyn_root = true;
455 else
456 as->cell = afs_get_cell(params->cell);
457 }
458 return as;
459 }
460
afs_destroy_sbi(struct afs_super_info * as)461 static void afs_destroy_sbi(struct afs_super_info *as)
462 {
463 if (as) {
464 afs_put_volume(as->cell, as->volume);
465 afs_put_cell(afs_net(as->net_ns), as->cell);
466 put_net(as->net_ns);
467 kfree(as);
468 }
469 }
470
afs_kill_super(struct super_block * sb)471 static void afs_kill_super(struct super_block *sb)
472 {
473 struct afs_super_info *as = AFS_FS_S(sb);
474 struct afs_net *net = afs_net(as->net_ns);
475
476 if (as->dyn_root)
477 afs_dynroot_depopulate(sb);
478
479 /* Clear the callback interests (which will do ilookup5) before
480 * deactivating the superblock.
481 */
482 if (as->volume)
483 afs_clear_callback_interests(net, as->volume->servers);
484 kill_anon_super(sb);
485 if (as->volume)
486 afs_deactivate_volume(as->volume);
487 afs_destroy_sbi(as);
488 }
489
490 /*
491 * get an AFS superblock
492 */
afs_mount(struct file_system_type * fs_type,int flags,const char * dev_name,void * options)493 static struct dentry *afs_mount(struct file_system_type *fs_type,
494 int flags, const char *dev_name, void *options)
495 {
496 struct afs_mount_params params;
497 struct super_block *sb;
498 struct afs_volume *candidate;
499 struct key *key;
500 struct afs_super_info *as;
501 int ret;
502
503 _enter(",,%s,%p", dev_name, options);
504
505 memset(¶ms, 0, sizeof(params));
506
507 ret = -EINVAL;
508 if (current->nsproxy->net_ns != &init_net)
509 goto error;
510 params.net_ns = current->nsproxy->net_ns;
511 params.net = afs_net(params.net_ns);
512
513 /* parse the options and device name */
514 if (options) {
515 ret = afs_parse_options(¶ms, options, &dev_name);
516 if (ret < 0)
517 goto error;
518 }
519
520 if (!params.dyn_root) {
521 ret = afs_parse_device_name(¶ms, dev_name);
522 if (ret < 0)
523 goto error;
524
525 /* try and do the mount securely */
526 key = afs_request_key(params.cell);
527 if (IS_ERR(key)) {
528 _leave(" = %ld [key]", PTR_ERR(key));
529 ret = PTR_ERR(key);
530 goto error;
531 }
532 params.key = key;
533 }
534
535 /* allocate a superblock info record */
536 ret = -ENOMEM;
537 as = afs_alloc_sbi(¶ms);
538 if (!as)
539 goto error_key;
540
541 if (!params.dyn_root) {
542 /* Assume we're going to need a volume record; at the very
543 * least we can use it to update the volume record if we have
544 * one already. This checks that the volume exists within the
545 * cell.
546 */
547 candidate = afs_create_volume(¶ms);
548 if (IS_ERR(candidate)) {
549 ret = PTR_ERR(candidate);
550 goto error_as;
551 }
552
553 as->volume = candidate;
554 }
555
556 /* allocate a deviceless superblock */
557 sb = sget(fs_type,
558 as->dyn_root ? afs_dynroot_test_super : afs_test_super,
559 afs_set_super, flags, as);
560 if (IS_ERR(sb)) {
561 ret = PTR_ERR(sb);
562 goto error_as;
563 }
564
565 if (!sb->s_root) {
566 /* initial superblock/root creation */
567 _debug("create");
568 ret = afs_fill_super(sb, ¶ms);
569 if (ret < 0)
570 goto error_sb;
571 as = NULL;
572 sb->s_flags |= SB_ACTIVE;
573 } else {
574 _debug("reuse");
575 ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
576 afs_destroy_sbi(as);
577 as = NULL;
578 }
579
580 afs_put_cell(params.net, params.cell);
581 key_put(params.key);
582 _leave(" = 0 [%p]", sb);
583 return dget(sb->s_root);
584
585 error_sb:
586 deactivate_locked_super(sb);
587 goto error_key;
588 error_as:
589 afs_destroy_sbi(as);
590 error_key:
591 key_put(params.key);
592 error:
593 afs_put_cell(params.net, params.cell);
594 _leave(" = %d", ret);
595 return ERR_PTR(ret);
596 }
597
598 /*
599 * Initialise an inode cache slab element prior to any use. Note that
600 * afs_alloc_inode() *must* reset anything that could incorrectly leak from one
601 * inode to another.
602 */
afs_i_init_once(void * _vnode)603 static void afs_i_init_once(void *_vnode)
604 {
605 struct afs_vnode *vnode = _vnode;
606
607 memset(vnode, 0, sizeof(*vnode));
608 inode_init_once(&vnode->vfs_inode);
609 mutex_init(&vnode->io_lock);
610 init_rwsem(&vnode->validate_lock);
611 spin_lock_init(&vnode->wb_lock);
612 spin_lock_init(&vnode->lock);
613 INIT_LIST_HEAD(&vnode->wb_keys);
614 INIT_LIST_HEAD(&vnode->pending_locks);
615 INIT_LIST_HEAD(&vnode->granted_locks);
616 INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
617 seqlock_init(&vnode->cb_lock);
618 }
619
620 /*
621 * allocate an AFS inode struct from our slab cache
622 */
afs_alloc_inode(struct super_block * sb)623 static struct inode *afs_alloc_inode(struct super_block *sb)
624 {
625 struct afs_vnode *vnode;
626
627 vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
628 if (!vnode)
629 return NULL;
630
631 atomic_inc(&afs_count_active_inodes);
632
633 /* Reset anything that shouldn't leak from one inode to the next. */
634 memset(&vnode->fid, 0, sizeof(vnode->fid));
635 memset(&vnode->status, 0, sizeof(vnode->status));
636
637 vnode->volume = NULL;
638 vnode->lock_key = NULL;
639 vnode->permit_cache = NULL;
640 vnode->cb_interest = NULL;
641 #ifdef CONFIG_AFS_FSCACHE
642 vnode->cache = NULL;
643 #endif
644
645 vnode->flags = 1 << AFS_VNODE_UNSET;
646 vnode->cb_type = 0;
647 vnode->lock_state = AFS_VNODE_LOCK_NONE;
648
649 _leave(" = %p", &vnode->vfs_inode);
650 return &vnode->vfs_inode;
651 }
652
afs_i_callback(struct rcu_head * head)653 static void afs_i_callback(struct rcu_head *head)
654 {
655 struct inode *inode = container_of(head, struct inode, i_rcu);
656 struct afs_vnode *vnode = AFS_FS_I(inode);
657 kmem_cache_free(afs_inode_cachep, vnode);
658 }
659
660 /*
661 * destroy an AFS inode struct
662 */
afs_destroy_inode(struct inode * inode)663 static void afs_destroy_inode(struct inode *inode)
664 {
665 struct afs_vnode *vnode = AFS_FS_I(inode);
666
667 _enter("%p{%x:%u}", inode, vnode->fid.vid, vnode->fid.vnode);
668
669 _debug("DESTROY INODE %p", inode);
670
671 ASSERTCMP(vnode->cb_interest, ==, NULL);
672
673 call_rcu(&inode->i_rcu, afs_i_callback);
674 atomic_dec(&afs_count_active_inodes);
675 }
676
677 /*
678 * return information about an AFS volume
679 */
afs_statfs(struct dentry * dentry,struct kstatfs * buf)680 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
681 {
682 struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
683 struct afs_fs_cursor fc;
684 struct afs_volume_status vs;
685 struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
686 struct key *key;
687 int ret;
688
689 buf->f_type = dentry->d_sb->s_magic;
690 buf->f_bsize = AFS_BLOCK_SIZE;
691 buf->f_namelen = AFSNAMEMAX - 1;
692
693 if (as->dyn_root) {
694 buf->f_blocks = 1;
695 buf->f_bavail = 0;
696 buf->f_bfree = 0;
697 return 0;
698 }
699
700 key = afs_request_key(vnode->volume->cell);
701 if (IS_ERR(key))
702 return PTR_ERR(key);
703
704 ret = -ERESTARTSYS;
705 if (afs_begin_vnode_operation(&fc, vnode, key)) {
706 fc.flags |= AFS_FS_CURSOR_NO_VSLEEP;
707 while (afs_select_fileserver(&fc)) {
708 fc.cb_break = afs_calc_vnode_cb_break(vnode);
709 afs_fs_get_volume_status(&fc, &vs);
710 }
711
712 afs_check_for_remote_deletion(&fc, fc.vnode);
713 afs_vnode_commit_status(&fc, vnode, fc.cb_break);
714 ret = afs_end_vnode_operation(&fc);
715 }
716
717 key_put(key);
718
719 if (ret == 0) {
720 if (vs.max_quota == 0)
721 buf->f_blocks = vs.part_max_blocks;
722 else
723 buf->f_blocks = vs.max_quota;
724 buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
725 }
726
727 return ret;
728 }
729