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_spec 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 .write_inode = netfs_unpin_writeback,
59 .drop_inode = afs_drop_inode,
60 .destroy_inode = afs_destroy_inode,
61 .free_inode = afs_free_inode,
62 .evict_inode = afs_evict_inode,
63 .show_devname = afs_show_devname,
64 .show_options = afs_show_options,
65 };
66
67 static struct kmem_cache *afs_inode_cachep;
68 static atomic_t afs_count_active_inodes;
69
70 enum afs_param {
71 Opt_autocell,
72 Opt_dyn,
73 Opt_flock,
74 Opt_source,
75 };
76
77 static const struct constant_table afs_param_flock[] = {
78 {"local", afs_flock_mode_local },
79 {"openafs", afs_flock_mode_openafs },
80 {"strict", afs_flock_mode_strict },
81 {"write", afs_flock_mode_write },
82 {}
83 };
84
85 static const struct fs_parameter_spec afs_fs_parameters[] = {
86 fsparam_flag ("autocell", Opt_autocell),
87 fsparam_flag ("dyn", Opt_dyn),
88 fsparam_enum ("flock", Opt_flock, afs_param_flock),
89 fsparam_string("source", Opt_source),
90 {}
91 };
92
93 /*
94 * initialise the filesystem
95 */
96 int __init afs_fs_init(void)
97 {
98 int ret;
99
100 _enter("");
101
102 /* create ourselves an inode cache */
103 atomic_set(&afs_count_active_inodes, 0);
104
105 ret = -ENOMEM;
106 afs_inode_cachep = kmem_cache_create("afs_inode_cache",
107 sizeof(struct afs_vnode),
108 0,
109 SLAB_HWCACHE_ALIGN|SLAB_ACCOUNT,
110 afs_i_init_once);
111 if (!afs_inode_cachep) {
112 printk(KERN_NOTICE "kAFS: Failed to allocate inode cache\n");
113 return ret;
114 }
115
116 /* now export our filesystem to lesser mortals */
117 ret = register_filesystem(&afs_fs_type);
118 if (ret < 0) {
119 kmem_cache_destroy(afs_inode_cachep);
120 _leave(" = %d", ret);
121 return ret;
122 }
123
124 _leave(" = 0");
125 return 0;
126 }
127
128 /*
129 * clean up the filesystem
130 */
131 void afs_fs_exit(void)
132 {
133 _enter("");
134
135 afs_mntpt_kill_timer();
136 unregister_filesystem(&afs_fs_type);
137
138 if (atomic_read(&afs_count_active_inodes) != 0) {
139 printk("kAFS: %d active inode objects still present\n",
140 atomic_read(&afs_count_active_inodes));
141 BUG();
142 }
143
144 /*
145 * Make sure all delayed rcu free inodes are flushed before we
146 * destroy cache.
147 */
148 rcu_barrier();
149 kmem_cache_destroy(afs_inode_cachep);
150 _leave("");
151 }
152
153 /*
154 * Display the mount device name in /proc/mounts.
155 */
156 static int afs_show_devname(struct seq_file *m, struct dentry *root)
157 {
158 struct afs_super_info *as = AFS_FS_S(root->d_sb);
159 struct afs_volume *volume = as->volume;
160 struct afs_cell *cell = as->cell;
161 const char *suf = "";
162 char pref = '%';
163
164 if (as->dyn_root) {
165 seq_puts(m, "none");
166 return 0;
167 }
168
169 switch (volume->type) {
170 case AFSVL_RWVOL:
171 break;
172 case AFSVL_ROVOL:
173 pref = '#';
174 if (volume->type_force)
175 suf = ".readonly";
176 break;
177 case AFSVL_BACKVOL:
178 pref = '#';
179 suf = ".backup";
180 break;
181 }
182
183 seq_printf(m, "%c%s:%s%s", pref, cell->name, volume->name, suf);
184 return 0;
185 }
186
187 /*
188 * Display the mount options in /proc/mounts.
189 */
190 static int afs_show_options(struct seq_file *m, struct dentry *root)
191 {
192 struct afs_super_info *as = AFS_FS_S(root->d_sb);
193 const char *p = NULL;
194
195 if (as->dyn_root)
196 seq_puts(m, ",dyn");
197 if (test_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(d_inode(root))->flags))
198 seq_puts(m, ",autocell");
199 switch (as->flock_mode) {
200 case afs_flock_mode_unset: break;
201 case afs_flock_mode_local: p = "local"; break;
202 case afs_flock_mode_openafs: p = "openafs"; break;
203 case afs_flock_mode_strict: p = "strict"; break;
204 case afs_flock_mode_write: p = "write"; break;
205 }
206 if (p)
207 seq_printf(m, ",flock=%s", p);
208
209 return 0;
210 }
211
212 /*
213 * Parse the source name to get cell name, volume name, volume type and R/W
214 * selector.
215 *
216 * This can be one of the following:
217 * "%[cell:]volume[.]" R/W volume
218 * "#[cell:]volume[.]" R/O or R/W volume (R/O parent),
219 * or R/W (R/W parent) volume
220 * "%[cell:]volume.readonly" R/O volume
221 * "#[cell:]volume.readonly" R/O volume
222 * "%[cell:]volume.backup" Backup volume
223 * "#[cell:]volume.backup" Backup volume
224 */
225 static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
226 {
227 struct afs_fs_context *ctx = fc->fs_private;
228 struct afs_cell *cell;
229 const char *cellname, *suffix, *name = param->string;
230 int cellnamesz;
231
232 _enter(",%s", name);
233
234 if (fc->source)
235 return invalf(fc, "kAFS: Multiple sources not supported");
236
237 if (!name) {
238 printk(KERN_ERR "kAFS: no volume name specified\n");
239 return -EINVAL;
240 }
241
242 if ((name[0] != '%' && name[0] != '#') || !name[1]) {
243 /* To use dynroot, we don't want to have to provide a source */
244 if (strcmp(name, "none") == 0) {
245 ctx->no_cell = true;
246 return 0;
247 }
248 printk(KERN_ERR "kAFS: unparsable volume name\n");
249 return -EINVAL;
250 }
251
252 /* determine the type of volume we're looking for */
253 if (name[0] == '%') {
254 ctx->type = AFSVL_RWVOL;
255 ctx->force = true;
256 }
257 name++;
258
259 /* split the cell name out if there is one */
260 ctx->volname = strchr(name, ':');
261 if (ctx->volname) {
262 cellname = name;
263 cellnamesz = ctx->volname - name;
264 ctx->volname++;
265 } else {
266 ctx->volname = name;
267 cellname = NULL;
268 cellnamesz = 0;
269 }
270
271 /* the volume type is further affected by a possible suffix */
272 suffix = strrchr(ctx->volname, '.');
273 if (suffix) {
274 if (strcmp(suffix, ".readonly") == 0) {
275 ctx->type = AFSVL_ROVOL;
276 ctx->force = true;
277 } else if (strcmp(suffix, ".backup") == 0) {
278 ctx->type = AFSVL_BACKVOL;
279 ctx->force = true;
280 } else if (suffix[1] == 0) {
281 } else {
282 suffix = NULL;
283 }
284 }
285
286 ctx->volnamesz = suffix ?
287 suffix - ctx->volname : strlen(ctx->volname);
288
289 _debug("cell %*.*s [%p]",
290 cellnamesz, cellnamesz, cellname ?: "", ctx->cell);
291
292 /* lookup the cell record */
293 if (cellname) {
294 cell = afs_lookup_cell(ctx->net, cellname, cellnamesz,
295 NULL, false);
296 if (IS_ERR(cell)) {
297 pr_err("kAFS: unable to lookup cell '%*.*s'\n",
298 cellnamesz, cellnamesz, cellname ?: "");
299 return PTR_ERR(cell);
300 }
301 afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_parse);
302 afs_see_cell(cell, afs_cell_trace_see_source);
303 ctx->cell = cell;
304 }
305
306 _debug("CELL:%s [%p] VOLUME:%*.*s SUFFIX:%s TYPE:%d%s",
307 ctx->cell->name, ctx->cell,
308 ctx->volnamesz, ctx->volnamesz, ctx->volname,
309 suffix ?: "-", ctx->type, ctx->force ? " FORCE" : "");
310
311 fc->source = param->string;
312 param->string = NULL;
313 return 0;
314 }
315
316 /*
317 * Parse a single mount parameter.
318 */
319 static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
320 {
321 struct fs_parse_result result;
322 struct afs_fs_context *ctx = fc->fs_private;
323 int opt;
324
325 opt = fs_parse(fc, afs_fs_parameters, param, &result);
326 if (opt < 0)
327 return opt;
328
329 switch (opt) {
330 case Opt_source:
331 return afs_parse_source(fc, param);
332
333 case Opt_autocell:
334 ctx->autocell = true;
335 break;
336
337 case Opt_dyn:
338 ctx->dyn_root = true;
339 break;
340
341 case Opt_flock:
342 ctx->flock_mode = result.uint_32;
343 break;
344
345 default:
346 return -EINVAL;
347 }
348
349 _leave(" = 0");
350 return 0;
351 }
352
353 /*
354 * Validate the options, get the cell key and look up the volume.
355 */
356 static int afs_validate_fc(struct fs_context *fc)
357 {
358 struct afs_fs_context *ctx = fc->fs_private;
359 struct afs_volume *volume;
360 struct afs_cell *cell;
361 struct key *key;
362 int ret;
363
364 if (!ctx->dyn_root) {
365 if (ctx->no_cell) {
366 pr_warn("kAFS: Can only specify source 'none' with -o dyn\n");
367 return -EINVAL;
368 }
369
370 if (!ctx->cell) {
371 pr_warn("kAFS: No cell specified\n");
372 return -EDESTADDRREQ;
373 }
374
375 reget_key:
376 /* We try to do the mount securely. */
377 key = afs_request_key(ctx->cell);
378 if (IS_ERR(key))
379 return PTR_ERR(key);
380
381 ctx->key = key;
382
383 if (ctx->volume) {
384 afs_put_volume(ctx->volume, afs_volume_trace_put_validate_fc);
385 ctx->volume = NULL;
386 }
387
388 if (test_bit(AFS_CELL_FL_CHECK_ALIAS, &ctx->cell->flags)) {
389 ret = afs_cell_detect_alias(ctx->cell, key);
390 if (ret < 0)
391 return ret;
392 if (ret == 1) {
393 _debug("switch to alias");
394 key_put(ctx->key);
395 ctx->key = NULL;
396 cell = afs_use_cell(ctx->cell->alias_of,
397 afs_cell_trace_use_fc_alias);
398 afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
399 ctx->cell = cell;
400 goto reget_key;
401 }
402 }
403
404 volume = afs_create_volume(ctx);
405 if (IS_ERR(volume))
406 return PTR_ERR(volume);
407
408 ctx->volume = volume;
409 if (volume->type != AFSVL_RWVOL) {
410 ctx->flock_mode = afs_flock_mode_local;
411 fc->sb_flags |= SB_RDONLY;
412 }
413 }
414
415 return 0;
416 }
417
418 /*
419 * check a superblock to see if it's the one we're looking for
420 */
421 static int afs_test_super(struct super_block *sb, struct fs_context *fc)
422 {
423 struct afs_fs_context *ctx = fc->fs_private;
424 struct afs_super_info *as = AFS_FS_S(sb);
425
426 return (as->net_ns == fc->net_ns &&
427 as->volume &&
428 as->volume->vid == ctx->volume->vid &&
429 as->cell == ctx->cell &&
430 !as->dyn_root);
431 }
432
433 static int afs_dynroot_test_super(struct super_block *sb, struct fs_context *fc)
434 {
435 struct afs_super_info *as = AFS_FS_S(sb);
436
437 return (as->net_ns == fc->net_ns &&
438 as->dyn_root);
439 }
440
441 static int afs_set_super(struct super_block *sb, struct fs_context *fc)
442 {
443 return set_anon_super(sb, NULL);
444 }
445
446 /*
447 * fill in the superblock
448 */
449 static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
450 {
451 struct afs_super_info *as = AFS_FS_S(sb);
452 struct inode *inode = NULL;
453 int ret;
454
455 _enter("");
456
457 /* fill in the superblock */
458 sb->s_blocksize = PAGE_SIZE;
459 sb->s_blocksize_bits = PAGE_SHIFT;
460 sb->s_maxbytes = MAX_LFS_FILESIZE;
461 sb->s_magic = AFS_FS_MAGIC;
462 sb->s_op = &afs_super_ops;
463 if (!as->dyn_root)
464 sb->s_xattr = afs_xattr_handlers;
465 ret = super_setup_bdi(sb);
466 if (ret)
467 return ret;
468
469 /* allocate the root inode and dentry */
470 if (as->dyn_root) {
471 inode = afs_iget_pseudo_dir(sb, true);
472 } else {
473 sprintf(sb->s_id, "%llu", as->volume->vid);
474 afs_activate_volume(as->volume);
475 inode = afs_root_iget(sb, ctx->key);
476 }
477
478 if (IS_ERR(inode))
479 return PTR_ERR(inode);
480
481 if (ctx->autocell || as->dyn_root)
482 set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
483
484 ret = -ENOMEM;
485 sb->s_root = d_make_root(inode);
486 if (!sb->s_root)
487 goto error;
488
489 if (as->dyn_root) {
490 sb->s_d_op = &afs_dynroot_dentry_operations;
491 ret = afs_dynroot_populate(sb);
492 if (ret < 0)
493 goto error;
494 } else {
495 sb->s_d_op = &afs_fs_dentry_operations;
496 rcu_assign_pointer(as->volume->sb, sb);
497 }
498
499 _leave(" = 0");
500 return 0;
501
502 error:
503 _leave(" = %d", ret);
504 return ret;
505 }
506
507 static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
508 {
509 struct afs_fs_context *ctx = fc->fs_private;
510 struct afs_super_info *as;
511
512 as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
513 if (as) {
514 as->net_ns = get_net(fc->net_ns);
515 as->flock_mode = ctx->flock_mode;
516 if (ctx->dyn_root) {
517 as->dyn_root = true;
518 } else {
519 as->cell = afs_use_cell(ctx->cell, afs_cell_trace_use_sbi);
520 as->volume = afs_get_volume(ctx->volume,
521 afs_volume_trace_get_alloc_sbi);
522 }
523 }
524 return as;
525 }
526
527 static void afs_destroy_sbi(struct afs_super_info *as)
528 {
529 if (as) {
530 struct afs_net *net = afs_net(as->net_ns);
531 afs_put_volume(as->volume, afs_volume_trace_put_destroy_sbi);
532 afs_unuse_cell(net, as->cell, afs_cell_trace_unuse_sbi);
533 put_net(as->net_ns);
534 kfree(as);
535 }
536 }
537
538 static void afs_kill_super(struct super_block *sb)
539 {
540 struct afs_super_info *as = AFS_FS_S(sb);
541
542 if (as->dyn_root)
543 afs_dynroot_depopulate(sb);
544
545 /* Clear the callback interests (which will do ilookup5) before
546 * deactivating the superblock.
547 */
548 if (as->volume)
549 rcu_assign_pointer(as->volume->sb, NULL);
550 kill_anon_super(sb);
551 if (as->volume)
552 afs_deactivate_volume(as->volume);
553 afs_destroy_sbi(as);
554 }
555
556 /*
557 * Get an AFS superblock and root directory.
558 */
559 static int afs_get_tree(struct fs_context *fc)
560 {
561 struct afs_fs_context *ctx = fc->fs_private;
562 struct super_block *sb;
563 struct afs_super_info *as;
564 int ret;
565
566 ret = afs_validate_fc(fc);
567 if (ret)
568 goto error;
569
570 _enter("");
571
572 /* allocate a superblock info record */
573 ret = -ENOMEM;
574 as = afs_alloc_sbi(fc);
575 if (!as)
576 goto error;
577 fc->s_fs_info = as;
578
579 /* allocate a deviceless superblock */
580 sb = sget_fc(fc,
581 as->dyn_root ? afs_dynroot_test_super : afs_test_super,
582 afs_set_super);
583 if (IS_ERR(sb)) {
584 ret = PTR_ERR(sb);
585 goto error;
586 }
587
588 if (!sb->s_root) {
589 /* initial superblock/root creation */
590 _debug("create");
591 ret = afs_fill_super(sb, ctx);
592 if (ret < 0)
593 goto error_sb;
594 sb->s_flags |= SB_ACTIVE;
595 } else {
596 _debug("reuse");
597 ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
598 }
599
600 fc->root = dget(sb->s_root);
601 trace_afs_get_tree(as->cell, as->volume);
602 _leave(" = 0 [%p]", sb);
603 return 0;
604
605 error_sb:
606 deactivate_locked_super(sb);
607 error:
608 _leave(" = %d", ret);
609 return ret;
610 }
611
612 static void afs_free_fc(struct fs_context *fc)
613 {
614 struct afs_fs_context *ctx = fc->fs_private;
615
616 afs_destroy_sbi(fc->s_fs_info);
617 afs_put_volume(ctx->volume, afs_volume_trace_put_free_fc);
618 afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
619 key_put(ctx->key);
620 kfree(ctx);
621 }
622
623 static const struct fs_context_operations afs_context_ops = {
624 .free = afs_free_fc,
625 .parse_param = afs_parse_param,
626 .get_tree = afs_get_tree,
627 };
628
629 /*
630 * Set up the filesystem mount context.
631 */
632 static int afs_init_fs_context(struct fs_context *fc)
633 {
634 struct afs_fs_context *ctx;
635 struct afs_cell *cell;
636
637 ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL);
638 if (!ctx)
639 return -ENOMEM;
640
641 ctx->type = AFSVL_ROVOL;
642 ctx->net = afs_net(fc->net_ns);
643
644 /* Default to the workstation cell. */
645 cell = afs_find_cell(ctx->net, NULL, 0, afs_cell_trace_use_fc);
646 if (IS_ERR(cell))
647 cell = NULL;
648 ctx->cell = cell;
649
650 fc->fs_private = ctx;
651 fc->ops = &afs_context_ops;
652 return 0;
653 }
654
655 /*
656 * Initialise an inode cache slab element prior to any use. Note that
657 * afs_alloc_inode() *must* reset anything that could incorrectly leak from one
658 * inode to another.
659 */
660 static void afs_i_init_once(void *_vnode)
661 {
662 struct afs_vnode *vnode = _vnode;
663
664 memset(vnode, 0, sizeof(*vnode));
665 inode_init_once(&vnode->netfs.inode);
666 mutex_init(&vnode->io_lock);
667 init_rwsem(&vnode->validate_lock);
668 spin_lock_init(&vnode->wb_lock);
669 spin_lock_init(&vnode->lock);
670 INIT_LIST_HEAD(&vnode->wb_keys);
671 INIT_LIST_HEAD(&vnode->pending_locks);
672 INIT_LIST_HEAD(&vnode->granted_locks);
673 INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
674 INIT_LIST_HEAD(&vnode->cb_mmap_link);
675 seqlock_init(&vnode->cb_lock);
676 }
677
678 /*
679 * allocate an AFS inode struct from our slab cache
680 */
681 static struct inode *afs_alloc_inode(struct super_block *sb)
682 {
683 struct afs_vnode *vnode;
684
685 vnode = alloc_inode_sb(sb, afs_inode_cachep, GFP_KERNEL);
686 if (!vnode)
687 return NULL;
688
689 atomic_inc(&afs_count_active_inodes);
690
691 /* Reset anything that shouldn't leak from one inode to the next. */
692 memset(&vnode->fid, 0, sizeof(vnode->fid));
693 memset(&vnode->status, 0, sizeof(vnode->status));
694 afs_vnode_set_cache(vnode, NULL);
695
696 vnode->volume = NULL;
697 vnode->lock_key = NULL;
698 vnode->permit_cache = NULL;
699
700 vnode->flags = 1 << AFS_VNODE_UNSET;
701 vnode->lock_state = AFS_VNODE_LOCK_NONE;
702
703 init_rwsem(&vnode->rmdir_lock);
704 INIT_WORK(&vnode->cb_work, afs_invalidate_mmap_work);
705
706 _leave(" = %p", &vnode->netfs.inode);
707 return &vnode->netfs.inode;
708 }
709
710 static void afs_free_inode(struct inode *inode)
711 {
712 kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
713 }
714
715 /*
716 * destroy an AFS inode struct
717 */
718 static void afs_destroy_inode(struct inode *inode)
719 {
720 struct afs_vnode *vnode = AFS_FS_I(inode);
721
722 _enter("%p{%llx:%llu}", inode, vnode->fid.vid, vnode->fid.vnode);
723
724 _debug("DESTROY INODE %p", inode);
725
726 atomic_dec(&afs_count_active_inodes);
727 }
728
729 static void afs_get_volume_status_success(struct afs_operation *op)
730 {
731 struct afs_volume_status *vs = &op->volstatus.vs;
732 struct kstatfs *buf = op->volstatus.buf;
733
734 if (vs->max_quota == 0)
735 buf->f_blocks = vs->part_max_blocks;
736 else
737 buf->f_blocks = vs->max_quota;
738
739 if (buf->f_blocks > vs->blocks_in_use)
740 buf->f_bavail = buf->f_bfree =
741 buf->f_blocks - vs->blocks_in_use;
742 }
743
744 static const struct afs_operation_ops afs_get_volume_status_operation = {
745 .issue_afs_rpc = afs_fs_get_volume_status,
746 .issue_yfs_rpc = yfs_fs_get_volume_status,
747 .success = afs_get_volume_status_success,
748 };
749
750 /*
751 * return information about an AFS volume
752 */
753 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
754 {
755 struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
756 struct afs_operation *op;
757 struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
758
759 buf->f_type = dentry->d_sb->s_magic;
760 buf->f_bsize = AFS_BLOCK_SIZE;
761 buf->f_namelen = AFSNAMEMAX - 1;
762
763 if (as->dyn_root) {
764 buf->f_blocks = 1;
765 buf->f_bavail = 0;
766 buf->f_bfree = 0;
767 return 0;
768 }
769
770 op = afs_alloc_operation(NULL, as->volume);
771 if (IS_ERR(op))
772 return PTR_ERR(op);
773
774 afs_op_set_vnode(op, 0, vnode);
775 op->nr_files = 1;
776 op->volstatus.buf = buf;
777 op->ops = &afs_get_volume_status_operation;
778 return afs_do_sync_operation(op);
779 }
780
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