1 /* AFS superblock handling
2 *
3 * Copyright (c) 2002, 2007, 2018 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/fs_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 void afs_kill_super(struct super_block *sb);
34 static struct inode *afs_alloc_inode(struct super_block *sb);
35 static void afs_destroy_inode(struct inode *inode);
36 static void afs_free_inode(struct inode *inode);
37 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf);
38 static int afs_show_devname(struct seq_file *m, struct dentry *root);
39 static int afs_show_options(struct seq_file *m, struct dentry *root);
40 static int afs_init_fs_context(struct fs_context *fc);
41 static const struct fs_parameter_description afs_fs_parameters;
42
43 struct file_system_type afs_fs_type = {
44 .owner = THIS_MODULE,
45 .name = "afs",
46 .init_fs_context = afs_init_fs_context,
47 .parameters = &afs_fs_parameters,
48 .kill_sb = afs_kill_super,
49 .fs_flags = FS_RENAME_DOES_D_MOVE,
50 };
51 MODULE_ALIAS_FS("afs");
52
53 int afs_net_id;
54
55 static const struct super_operations afs_super_ops = {
56 .statfs = afs_statfs,
57 .alloc_inode = afs_alloc_inode,
58 .drop_inode = afs_drop_inode,
59 .destroy_inode = afs_destroy_inode,
60 .free_inode = afs_free_inode,
61 .evict_inode = afs_evict_inode,
62 .show_devname = afs_show_devname,
63 .show_options = afs_show_options,
64 };
65
66 static struct kmem_cache *afs_inode_cachep;
67 static atomic_t afs_count_active_inodes;
68
69 enum afs_param {
70 Opt_autocell,
71 Opt_dyn,
72 Opt_flock,
73 Opt_source,
74 };
75
76 static const struct fs_parameter_spec afs_param_specs[] = {
77 fsparam_flag ("autocell", Opt_autocell),
78 fsparam_flag ("dyn", Opt_dyn),
79 fsparam_enum ("flock", Opt_flock),
80 fsparam_string("source", Opt_source),
81 {}
82 };
83
84 static const struct fs_parameter_enum afs_param_enums[] = {
85 { Opt_flock, "local", afs_flock_mode_local },
86 { Opt_flock, "openafs", afs_flock_mode_openafs },
87 { Opt_flock, "strict", afs_flock_mode_strict },
88 { Opt_flock, "write", afs_flock_mode_write },
89 {}
90 };
91
92 static const struct fs_parameter_description afs_fs_parameters = {
93 .name = "kAFS",
94 .specs = afs_param_specs,
95 .enums = afs_param_enums,
96 };
97
98 /*
99 * initialise the filesystem
100 */
afs_fs_init(void)101 int __init afs_fs_init(void)
102 {
103 int ret;
104
105 _enter("");
106
107 /* create ourselves an inode cache */
108 atomic_set(&afs_count_active_inodes, 0);
109
110 ret = -ENOMEM;
111 afs_inode_cachep = kmem_cache_create("afs_inode_cache",
112 sizeof(struct afs_vnode),
113 0,
114 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
115 afs_i_init_once);
116 if (!afs_inode_cachep) {
117 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
118 return ret;
119 }
120
121 /* now export our filesystem to lesser mortals */
122 ret = register_filesystem(&afs_fs_type);
123 if (ret < 0) {
124 kmem_cache_destroy(afs_inode_cachep);
125 _leave(" = %d", ret);
126 return ret;
127 }
128
129 _leave(" = 0");
130 return 0;
131 }
132
133 /*
134 * clean up the filesystem
135 */
afs_fs_exit(void)136 void afs_fs_exit(void)
137 {
138 _enter("");
139
140 afs_mntpt_kill_timer();
141 unregister_filesystem(&afs_fs_type);
142
143 if (atomic_read(&afs_count_active_inodes) != 0) {
144 printk("kAFS: %d active inode objects still present\n",
145 atomic_read(&afs_count_active_inodes));
146 BUG();
147 }
148
149 /*
150 * Make sure all delayed rcu free inodes are flushed before we
151 * destroy cache.
152 */
153 rcu_barrier();
154 kmem_cache_destroy(afs_inode_cachep);
155 _leave("");
156 }
157
158 /*
159 * Display the mount device name in /proc/mounts.
160 */
afs_show_devname(struct seq_file * m,struct dentry * root)161 static int afs_show_devname(struct seq_file *m, struct dentry *root)
162 {
163 struct afs_super_info *as = AFS_FS_S(root->d_sb);
164 struct afs_volume *volume = as->volume;
165 struct afs_cell *cell = as->cell;
166 const char *suf = "";
167 char pref = '%';
168
169 if (as->dyn_root) {
170 seq_puts(m, "none");
171 return 0;
172 }
173
174 switch (volume->type) {
175 case AFSVL_RWVOL:
176 break;
177 case AFSVL_ROVOL:
178 pref = '#';
179 if (volume->type_force)
180 suf = ".readonly";
181 break;
182 case AFSVL_BACKVOL:
183 pref = '#';
184 suf = ".backup";
185 break;
186 }
187
188 seq_printf(m, "%c%s:%s%s", pref, cell->name, volume->name, suf);
189 return 0;
190 }
191
192 /*
193 * Display the mount options in /proc/mounts.
194 */
afs_show_options(struct seq_file * m,struct dentry * root)195 static int afs_show_options(struct seq_file *m, struct dentry *root)
196 {
197 struct afs_super_info *as = AFS_FS_S(root->d_sb);
198 const char *p = NULL;
199
200 if (as->dyn_root)
201 seq_puts(m, ",dyn");
202 if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
203 seq_puts(m, ",autocell");
204 switch (as->flock_mode) {
205 case afs_flock_mode_unset: break;
206 case afs_flock_mode_local: p = "local"; break;
207 case afs_flock_mode_openafs: p = "openafs"; break;
208 case afs_flock_mode_strict: p = "strict"; break;
209 case afs_flock_mode_write: p = "write"; break;
210 }
211 if (p)
212 seq_printf(m, ",flock=%s", p);
213
214 return 0;
215 }
216
217 /*
218 * Parse the source name to get cell name, volume name, volume type and R/W
219 * selector.
220 *
221 * This can be one of the following:
222 * "%[cell:]volume[.]" R/W volume
223 * "#[cell:]volume[.]" R/O or R/W volume (R/O parent),
224 * or R/W (R/W parent) volume
225 * "%[cell:]volume.readonly" R/O volume
226 * "#[cell:]volume.readonly" R/O volume
227 * "%[cell:]volume.backup" Backup volume
228 * "#[cell:]volume.backup" Backup volume
229 */
afs_parse_source(struct fs_context * fc,struct fs_parameter * param)230 static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
231 {
232 struct afs_fs_context *ctx = fc->fs_private;
233 struct afs_cell *cell;
234 const char *cellname, *suffix, *name = param->string;
235 int cellnamesz;
236
237 _enter(",%s", name);
238
239 if (!name) {
240 printk(KERN_ERR "kAFS: no volume name specified\n");
241 return -EINVAL;
242 }
243
244 if ((name[0] != '%' && name[0] != '#') || !name[1]) {
245 /* To use dynroot, we don't want to have to provide a source */
246 if (strcmp(name, "none") == 0) {
247 ctx->no_cell = true;
248 return 0;
249 }
250 printk(KERN_ERR "kAFS: unparsable volume name\n");
251 return -EINVAL;
252 }
253
254 /* determine the type of volume we're looking for */
255 if (name[0] == '%') {
256 ctx->type = AFSVL_RWVOL;
257 ctx->force = true;
258 }
259 name++;
260
261 /* split the cell name out if there is one */
262 ctx->volname = strchr(name, ':');
263 if (ctx->volname) {
264 cellname = name;
265 cellnamesz = ctx->volname - name;
266 ctx->volname++;
267 } else {
268 ctx->volname = name;
269 cellname = NULL;
270 cellnamesz = 0;
271 }
272
273 /* the volume type is further affected by a possible suffix */
274 suffix = strrchr(ctx->volname, '.');
275 if (suffix) {
276 if (strcmp(suffix, ".readonly") == 0) {
277 ctx->type = AFSVL_ROVOL;
278 ctx->force = true;
279 } else if (strcmp(suffix, ".backup") == 0) {
280 ctx->type = AFSVL_BACKVOL;
281 ctx->force = true;
282 } else if (suffix[1] == 0) {
283 } else {
284 suffix = NULL;
285 }
286 }
287
288 ctx->volnamesz = suffix ?
289 suffix - ctx->volname : strlen(ctx->volname);
290
291 _debug("cell %*.*s [%p]",
292 cellnamesz, cellnamesz, cellname ?: "", ctx->cell);
293
294 /* lookup the cell record */
295 if (cellname) {
296 cell = afs_lookup_cell(ctx->net, cellname, cellnamesz,
297 NULL, false);
298 if (IS_ERR(cell)) {
299 pr_err("kAFS: unable to lookup cell '%*.*s'\n",
300 cellnamesz, cellnamesz, cellname ?: "");
301 return PTR_ERR(cell);
302 }
303 afs_put_cell(ctx->net, ctx->cell);
304 ctx->cell = cell;
305 }
306
307 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
308 ctx->cell->name, ctx->cell,
309 ctx->volnamesz, ctx->volnamesz, ctx->volname,
310 suffix ?: "-", ctx->type, ctx->force ? " FORCE" : "");
311
312 fc->source = param->string;
313 param->string = NULL;
314 return 0;
315 }
316
317 /*
318 * Parse a single mount parameter.
319 */
afs_parse_param(struct fs_context * fc,struct fs_parameter * param)320 static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
321 {
322 struct fs_parse_result result;
323 struct afs_fs_context *ctx = fc->fs_private;
324 int opt;
325
326 opt = fs_parse(fc, &afs_fs_parameters, param, &result);
327 if (opt < 0)
328 return opt;
329
330 switch (opt) {
331 case Opt_source:
332 return afs_parse_source(fc, param);
333
334 case Opt_autocell:
335 ctx->autocell = true;
336 break;
337
338 case Opt_dyn:
339 ctx->dyn_root = true;
340 break;
341
342 case Opt_flock:
343 ctx->flock_mode = result.uint_32;
344 break;
345
346 default:
347 return -EINVAL;
348 }
349
350 _leave(" = 0");
351 return 0;
352 }
353
354 /*
355 * Validate the options, get the cell key and look up the volume.
356 */
afs_validate_fc(struct fs_context * fc)357 static int afs_validate_fc(struct fs_context *fc)
358 {
359 struct afs_fs_context *ctx = fc->fs_private;
360 struct afs_volume *volume;
361 struct key *key;
362
363 if (!ctx->dyn_root) {
364 if (ctx->no_cell) {
365 pr_warn("kAFS: Can only specify source 'none' with -o dyn\n");
366 return -EINVAL;
367 }
368
369 if (!ctx->cell) {
370 pr_warn("kAFS: No cell specified\n");
371 return -EDESTADDRREQ;
372 }
373
374 /* We try to do the mount securely. */
375 key = afs_request_key(ctx->cell);
376 if (IS_ERR(key))
377 return PTR_ERR(key);
378
379 ctx->key = key;
380
381 if (ctx->volume) {
382 afs_put_volume(ctx->cell, ctx->volume);
383 ctx->volume = NULL;
384 }
385
386 volume = afs_create_volume(ctx);
387 if (IS_ERR(volume))
388 return PTR_ERR(volume);
389
390 ctx->volume = volume;
391 }
392
393 return 0;
394 }
395
396 /*
397 * check a superblock to see if it's the one we're looking for
398 */
afs_test_super(struct super_block * sb,struct fs_context * fc)399 static int afs_test_super(struct super_block *sb, struct fs_context *fc)
400 {
401 struct afs_fs_context *ctx = fc->fs_private;
402 struct afs_super_info *as = AFS_FS_S(sb);
403
404 return (as->net_ns == fc->net_ns &&
405 as->volume &&
406 as->volume->vid == ctx->volume->vid &&
407 as->cell == ctx->cell &&
408 !as->dyn_root);
409 }
410
afs_dynroot_test_super(struct super_block * sb,struct fs_context * fc)411 static int afs_dynroot_test_super(struct super_block *sb, struct fs_context *fc)
412 {
413 struct afs_super_info *as = AFS_FS_S(sb);
414
415 return (as->net_ns == fc->net_ns &&
416 as->dyn_root);
417 }
418
afs_set_super(struct super_block * sb,struct fs_context * fc)419 static int afs_set_super(struct super_block *sb, struct fs_context *fc)
420 {
421 return set_anon_super(sb, NULL);
422 }
423
424 /*
425 * fill in the superblock
426 */
afs_fill_super(struct super_block * sb,struct afs_fs_context * ctx)427 static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
428 {
429 struct afs_super_info *as = AFS_FS_S(sb);
430 struct afs_iget_data iget_data;
431 struct inode *inode = NULL;
432 int ret;
433
434 _enter("");
435
436 /* fill in the superblock */
437 sb->s_blocksize = PAGE_SIZE;
438 sb->s_blocksize_bits = PAGE_SHIFT;
439 sb->s_maxbytes = MAX_LFS_FILESIZE;
440 sb->s_magic = AFS_FS_MAGIC;
441 sb->s_op = &afs_super_ops;
442 if (!as->dyn_root)
443 sb->s_xattr = afs_xattr_handlers;
444 ret = super_setup_bdi(sb);
445 if (ret)
446 return ret;
447 sb->s_bdi->ra_pages = VM_READAHEAD_PAGES;
448
449 /* allocate the root inode and dentry */
450 if (as->dyn_root) {
451 inode = afs_iget_pseudo_dir(sb, true);
452 } else {
453 sprintf(sb->s_id, "%llu", as->volume->vid);
454 afs_activate_volume(as->volume);
455 iget_data.fid.vid = as->volume->vid;
456 iget_data.fid.vnode = 1;
457 iget_data.fid.vnode_hi = 0;
458 iget_data.fid.unique = 1;
459 iget_data.cb_v_break = as->volume->cb_v_break;
460 iget_data.cb_s_break = 0;
461 inode = afs_iget(sb, ctx->key, &iget_data, NULL, NULL, NULL);
462 }
463
464 if (IS_ERR(inode))
465 return PTR_ERR(inode);
466
467 if (ctx->autocell || as->dyn_root)
468 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
469
470 ret = -ENOMEM;
471 sb->s_root = d_make_root(inode);
472 if (!sb->s_root)
473 goto error;
474
475 if (as->dyn_root) {
476 sb->s_d_op = &afs_dynroot_dentry_operations;
477 ret = afs_dynroot_populate(sb);
478 if (ret < 0)
479 goto error;
480 } else {
481 sb->s_d_op = &afs_fs_dentry_operations;
482 }
483
484 _leave(" = 0");
485 return 0;
486
487 error:
488 _leave(" = %d", ret);
489 return ret;
490 }
491
afs_alloc_sbi(struct fs_context * fc)492 static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
493 {
494 struct afs_fs_context *ctx = fc->fs_private;
495 struct afs_super_info *as;
496
497 as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
498 if (as) {
499 as->net_ns = get_net(fc->net_ns);
500 as->flock_mode = ctx->flock_mode;
501 if (ctx->dyn_root) {
502 as->dyn_root = true;
503 } else {
504 as->cell = afs_get_cell(ctx->cell);
505 as->volume = __afs_get_volume(ctx->volume);
506 }
507 }
508 return as;
509 }
510
afs_destroy_sbi(struct afs_super_info * as)511 static void afs_destroy_sbi(struct afs_super_info *as)
512 {
513 if (as) {
514 afs_put_volume(as->cell, as->volume);
515 afs_put_cell(afs_net(as->net_ns), as->cell);
516 put_net(as->net_ns);
517 kfree(as);
518 }
519 }
520
afs_kill_super(struct super_block * sb)521 static void afs_kill_super(struct super_block *sb)
522 {
523 struct afs_super_info *as = AFS_FS_S(sb);
524 struct afs_net *net = afs_net(as->net_ns);
525
526 if (as->dyn_root)
527 afs_dynroot_depopulate(sb);
528
529 /* Clear the callback interests (which will do ilookup5) before
530 * deactivating the superblock.
531 */
532 if (as->volume)
533 afs_clear_callback_interests(net, as->volume->servers);
534 kill_anon_super(sb);
535 if (as->volume)
536 afs_deactivate_volume(as->volume);
537 afs_destroy_sbi(as);
538 }
539
540 /*
541 * Get an AFS superblock and root directory.
542 */
afs_get_tree(struct fs_context * fc)543 static int afs_get_tree(struct fs_context *fc)
544 {
545 struct afs_fs_context *ctx = fc->fs_private;
546 struct super_block *sb;
547 struct afs_super_info *as;
548 int ret;
549
550 ret = afs_validate_fc(fc);
551 if (ret)
552 goto error;
553
554 _enter("");
555
556 /* allocate a superblock info record */
557 ret = -ENOMEM;
558 as = afs_alloc_sbi(fc);
559 if (!as)
560 goto error;
561 fc->s_fs_info = as;
562
563 /* allocate a deviceless superblock */
564 sb = sget_fc(fc,
565 as->dyn_root ? afs_dynroot_test_super : afs_test_super,
566 afs_set_super);
567 if (IS_ERR(sb)) {
568 ret = PTR_ERR(sb);
569 goto error;
570 }
571
572 if (!sb->s_root) {
573 /* initial superblock/root creation */
574 _debug("create");
575 ret = afs_fill_super(sb, ctx);
576 if (ret < 0)
577 goto error_sb;
578 sb->s_flags |= SB_ACTIVE;
579 } else {
580 _debug("reuse");
581 ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
582 }
583
584 fc->root = dget(sb->s_root);
585 trace_afs_get_tree(as->cell, as->volume);
586 _leave(" = 0 [%p]", sb);
587 return 0;
588
589 error_sb:
590 deactivate_locked_super(sb);
591 error:
592 _leave(" = %d", ret);
593 return ret;
594 }
595
afs_free_fc(struct fs_context * fc)596 static void afs_free_fc(struct fs_context *fc)
597 {
598 struct afs_fs_context *ctx = fc->fs_private;
599
600 afs_destroy_sbi(fc->s_fs_info);
601 afs_put_volume(ctx->cell, ctx->volume);
602 afs_put_cell(ctx->net, ctx->cell);
603 key_put(ctx->key);
604 kfree(ctx);
605 }
606
607 static const struct fs_context_operations afs_context_ops = {
608 .free = afs_free_fc,
609 .parse_param = afs_parse_param,
610 .get_tree = afs_get_tree,
611 };
612
613 /*
614 * Set up the filesystem mount context.
615 */
afs_init_fs_context(struct fs_context * fc)616 static int afs_init_fs_context(struct fs_context *fc)
617 {
618 struct afs_fs_context *ctx;
619 struct afs_cell *cell;
620
621 ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL);
622 if (!ctx)
623 return -ENOMEM;
624
625 ctx->type = AFSVL_ROVOL;
626 ctx->net = afs_net(fc->net_ns);
627
628 /* Default to the workstation cell. */
629 rcu_read_lock();
630 cell = afs_lookup_cell_rcu(ctx->net, NULL, 0);
631 rcu_read_unlock();
632 if (IS_ERR(cell))
633 cell = NULL;
634 ctx->cell = cell;
635
636 fc->fs_private = ctx;
637 fc->ops = &afs_context_ops;
638 return 0;
639 }
640
641 /*
642 * Initialise an inode cache slab element prior to any use. Note that
643 * afs_alloc_inode() *must* reset anything that could incorrectly leak from one
644 * inode to another.
645 */
afs_i_init_once(void * _vnode)646 static void afs_i_init_once(void *_vnode)
647 {
648 struct afs_vnode *vnode = _vnode;
649
650 memset(vnode, 0, sizeof(*vnode));
651 inode_init_once(&vnode->vfs_inode);
652 mutex_init(&vnode->io_lock);
653 init_rwsem(&vnode->validate_lock);
654 spin_lock_init(&vnode->wb_lock);
655 spin_lock_init(&vnode->lock);
656 INIT_LIST_HEAD(&vnode->wb_keys);
657 INIT_LIST_HEAD(&vnode->pending_locks);
658 INIT_LIST_HEAD(&vnode->granted_locks);
659 INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
660 seqlock_init(&vnode->cb_lock);
661 }
662
663 /*
664 * allocate an AFS inode struct from our slab cache
665 */
afs_alloc_inode(struct super_block * sb)666 static struct inode *afs_alloc_inode(struct super_block *sb)
667 {
668 struct afs_vnode *vnode;
669
670 vnode = kmem_cache_alloc(afs_inode_cachep, GFP_KERNEL);
671 if (!vnode)
672 return NULL;
673
674 atomic_inc(&afs_count_active_inodes);
675
676 /* Reset anything that shouldn't leak from one inode to the next. */
677 memset(&vnode->fid, 0, sizeof(vnode->fid));
678 memset(&vnode->status, 0, sizeof(vnode->status));
679
680 vnode->volume = NULL;
681 vnode->lock_key = NULL;
682 vnode->permit_cache = NULL;
683 RCU_INIT_POINTER(vnode->cb_interest, NULL);
684 #ifdef CONFIG_AFS_FSCACHE
685 vnode->cache = NULL;
686 #endif
687
688 vnode->flags = 1 << AFS_VNODE_UNSET;
689 vnode->lock_state = AFS_VNODE_LOCK_NONE;
690
691 init_rwsem(&vnode->rmdir_lock);
692
693 _leave(" = %p", &vnode->vfs_inode);
694 return &vnode->vfs_inode;
695 }
696
afs_free_inode(struct inode * inode)697 static void afs_free_inode(struct inode *inode)
698 {
699 kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
700 }
701
702 /*
703 * destroy an AFS inode struct
704 */
afs_destroy_inode(struct inode * inode)705 static void afs_destroy_inode(struct inode *inode)
706 {
707 struct afs_vnode *vnode = AFS_FS_I(inode);
708
709 _enter("%p{%llx:%llu}", inode, vnode->fid.vid, vnode->fid.vnode);
710
711 _debug("DESTROY INODE %p", inode);
712
713 ASSERTCMP(rcu_access_pointer(vnode->cb_interest), ==, NULL);
714
715 atomic_dec(&afs_count_active_inodes);
716 }
717
718 /*
719 * return information about an AFS volume
720 */
afs_statfs(struct dentry * dentry,struct kstatfs * buf)721 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
722 {
723 struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
724 struct afs_fs_cursor fc;
725 struct afs_volume_status vs;
726 struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
727 struct key *key;
728 int ret;
729
730 buf->f_type = dentry->d_sb->s_magic;
731 buf->f_bsize = AFS_BLOCK_SIZE;
732 buf->f_namelen = AFSNAMEMAX - 1;
733
734 if (as->dyn_root) {
735 buf->f_blocks = 1;
736 buf->f_bavail = 0;
737 buf->f_bfree = 0;
738 return 0;
739 }
740
741 key = afs_request_key(vnode->volume->cell);
742 if (IS_ERR(key))
743 return PTR_ERR(key);
744
745 ret = -ERESTARTSYS;
746 if (afs_begin_vnode_operation(&fc, vnode, key, true)) {
747 fc.flags |= AFS_FS_CURSOR_NO_VSLEEP;
748 while (afs_select_fileserver(&fc)) {
749 fc.cb_break = afs_calc_vnode_cb_break(vnode);
750 afs_fs_get_volume_status(&fc, &vs);
751 }
752
753 afs_check_for_remote_deletion(&fc, fc.vnode);
754 ret = afs_end_vnode_operation(&fc);
755 }
756
757 key_put(key);
758
759 if (ret == 0) {
760 if (vs.max_quota == 0)
761 buf->f_blocks = vs.part_max_blocks;
762 else
763 buf->f_blocks = vs.max_quota;
764 buf->f_bavail = buf->f_bfree = buf->f_blocks - vs.blocks_in_use;
765 }
766
767 return ret;
768 }
769