xref: /openbmc/linux/fs/afs/super.c (revision 747f7a29) 
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	= afs_write_inode,
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->net, ctx->volume,
385 				       afs_volume_trace_put_validate_fc);
386 			ctx->volume = NULL;
387 		}
388 
389 		if (test_bit(AFS_CELL_FL_CHECK_ALIAS, &ctx->cell->flags)) {
390 			ret = afs_cell_detect_alias(ctx->cell, key);
391 			if (ret < 0)
392 				return ret;
393 			if (ret == 1) {
394 				_debug("switch to alias");
395 				key_put(ctx->key);
396 				ctx->key = NULL;
397 				cell = afs_use_cell(ctx->cell->alias_of,
398 						    afs_cell_trace_use_fc_alias);
399 				afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
400 				ctx->cell = cell;
401 				goto reget_key;
402 			}
403 		}
404 
405 		volume = afs_create_volume(ctx);
406 		if (IS_ERR(volume))
407 			return PTR_ERR(volume);
408 
409 		ctx->volume = volume;
410 	}
411 
412 	return 0;
413 }
414 
415 /*
416  * check a superblock to see if it's the one we're looking for
417  */
418 static int afs_test_super(struct super_block *sb, struct fs_context *fc)
419 {
420 	struct afs_fs_context *ctx = fc->fs_private;
421 	struct afs_super_info *as = AFS_FS_S(sb);
422 
423 	return (as->net_ns == fc->net_ns &&
424 		as->volume &&
425 		as->volume->vid == ctx->volume->vid &&
426 		as->cell == ctx->cell &&
427 		!as->dyn_root);
428 }
429 
430 static int afs_dynroot_test_super(struct super_block *sb, struct fs_context *fc)
431 {
432 	struct afs_super_info *as = AFS_FS_S(sb);
433 
434 	return (as->net_ns == fc->net_ns &&
435 		as->dyn_root);
436 }
437 
438 static int afs_set_super(struct super_block *sb, struct fs_context *fc)
439 {
440 	return set_anon_super(sb, NULL);
441 }
442 
443 /*
444  * fill in the superblock
445  */
446 static int afs_fill_super(struct super_block *sb, struct afs_fs_context *ctx)
447 {
448 	struct afs_super_info *as = AFS_FS_S(sb);
449 	struct inode *inode = NULL;
450 	int ret;
451 
452 	_enter("");
453 
454 	/* fill in the superblock */
455 	sb->s_blocksize		= PAGE_SIZE;
456 	sb->s_blocksize_bits	= PAGE_SHIFT;
457 	sb->s_maxbytes		= MAX_LFS_FILESIZE;
458 	sb->s_magic		= AFS_FS_MAGIC;
459 	sb->s_op		= &afs_super_ops;
460 	if (!as->dyn_root)
461 		sb->s_xattr	= afs_xattr_handlers;
462 	ret = super_setup_bdi(sb);
463 	if (ret)
464 		return ret;
465 
466 	/* allocate the root inode and dentry */
467 	if (as->dyn_root) {
468 		inode = afs_iget_pseudo_dir(sb, true);
469 	} else {
470 		sprintf(sb->s_id, "%llu", as->volume->vid);
471 		afs_activate_volume(as->volume);
472 		inode = afs_root_iget(sb, ctx->key);
473 	}
474 
475 	if (IS_ERR(inode))
476 		return PTR_ERR(inode);
477 
478 	if (ctx->autocell || as->dyn_root)
479 		set_bit(AFS_VNODE_AUTOCELL, &AFS_FS_I(inode)->flags);
480 
481 	ret = -ENOMEM;
482 	sb->s_root = d_make_root(inode);
483 	if (!sb->s_root)
484 		goto error;
485 
486 	if (as->dyn_root) {
487 		sb->s_d_op = &afs_dynroot_dentry_operations;
488 		ret = afs_dynroot_populate(sb);
489 		if (ret < 0)
490 			goto error;
491 	} else {
492 		sb->s_d_op = &afs_fs_dentry_operations;
493 		rcu_assign_pointer(as->volume->sb, sb);
494 	}
495 
496 	_leave(" = 0");
497 	return 0;
498 
499 error:
500 	_leave(" = %d", ret);
501 	return ret;
502 }
503 
504 static struct afs_super_info *afs_alloc_sbi(struct fs_context *fc)
505 {
506 	struct afs_fs_context *ctx = fc->fs_private;
507 	struct afs_super_info *as;
508 
509 	as = kzalloc(sizeof(struct afs_super_info), GFP_KERNEL);
510 	if (as) {
511 		as->net_ns = get_net(fc->net_ns);
512 		as->flock_mode = ctx->flock_mode;
513 		if (ctx->dyn_root) {
514 			as->dyn_root = true;
515 		} else {
516 			as->cell = afs_use_cell(ctx->cell, afs_cell_trace_use_sbi);
517 			as->volume = afs_get_volume(ctx->volume,
518 						    afs_volume_trace_get_alloc_sbi);
519 		}
520 	}
521 	return as;
522 }
523 
524 static void afs_destroy_sbi(struct afs_super_info *as)
525 {
526 	if (as) {
527 		struct afs_net *net = afs_net(as->net_ns);
528 		afs_put_volume(net, as->volume, afs_volume_trace_put_destroy_sbi);
529 		afs_unuse_cell(net, as->cell, afs_cell_trace_unuse_sbi);
530 		put_net(as->net_ns);
531 		kfree(as);
532 	}
533 }
534 
535 static void afs_kill_super(struct super_block *sb)
536 {
537 	struct afs_super_info *as = AFS_FS_S(sb);
538 
539 	if (as->dyn_root)
540 		afs_dynroot_depopulate(sb);
541 
542 	/* Clear the callback interests (which will do ilookup5) before
543 	 * deactivating the superblock.
544 	 */
545 	if (as->volume)
546 		rcu_assign_pointer(as->volume->sb, NULL);
547 	kill_anon_super(sb);
548 	if (as->volume)
549 		afs_deactivate_volume(as->volume);
550 	afs_destroy_sbi(as);
551 }
552 
553 /*
554  * Get an AFS superblock and root directory.
555  */
556 static int afs_get_tree(struct fs_context *fc)
557 {
558 	struct afs_fs_context *ctx = fc->fs_private;
559 	struct super_block *sb;
560 	struct afs_super_info *as;
561 	int ret;
562 
563 	ret = afs_validate_fc(fc);
564 	if (ret)
565 		goto error;
566 
567 	_enter("");
568 
569 	/* allocate a superblock info record */
570 	ret = -ENOMEM;
571 	as = afs_alloc_sbi(fc);
572 	if (!as)
573 		goto error;
574 	fc->s_fs_info = as;
575 
576 	/* allocate a deviceless superblock */
577 	sb = sget_fc(fc,
578 		     as->dyn_root ? afs_dynroot_test_super : afs_test_super,
579 		     afs_set_super);
580 	if (IS_ERR(sb)) {
581 		ret = PTR_ERR(sb);
582 		goto error;
583 	}
584 
585 	if (!sb->s_root) {
586 		/* initial superblock/root creation */
587 		_debug("create");
588 		ret = afs_fill_super(sb, ctx);
589 		if (ret < 0)
590 			goto error_sb;
591 		sb->s_flags |= SB_ACTIVE;
592 	} else {
593 		_debug("reuse");
594 		ASSERTCMP(sb->s_flags, &, SB_ACTIVE);
595 	}
596 
597 	fc->root = dget(sb->s_root);
598 	trace_afs_get_tree(as->cell, as->volume);
599 	_leave(" = 0 [%p]", sb);
600 	return 0;
601 
602 error_sb:
603 	deactivate_locked_super(sb);
604 error:
605 	_leave(" = %d", ret);
606 	return ret;
607 }
608 
609 static void afs_free_fc(struct fs_context *fc)
610 {
611 	struct afs_fs_context *ctx = fc->fs_private;
612 
613 	afs_destroy_sbi(fc->s_fs_info);
614 	afs_put_volume(ctx->net, ctx->volume, afs_volume_trace_put_free_fc);
615 	afs_unuse_cell(ctx->net, ctx->cell, afs_cell_trace_unuse_fc);
616 	key_put(ctx->key);
617 	kfree(ctx);
618 }
619 
620 static const struct fs_context_operations afs_context_ops = {
621 	.free		= afs_free_fc,
622 	.parse_param	= afs_parse_param,
623 	.get_tree	= afs_get_tree,
624 };
625 
626 /*
627  * Set up the filesystem mount context.
628  */
629 static int afs_init_fs_context(struct fs_context *fc)
630 {
631 	struct afs_fs_context *ctx;
632 	struct afs_cell *cell;
633 
634 	ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL);
635 	if (!ctx)
636 		return -ENOMEM;
637 
638 	ctx->type = AFSVL_ROVOL;
639 	ctx->net = afs_net(fc->net_ns);
640 
641 	/* Default to the workstation cell. */
642 	cell = afs_find_cell(ctx->net, NULL, 0, afs_cell_trace_use_fc);
643 	if (IS_ERR(cell))
644 		cell = NULL;
645 	ctx->cell = cell;
646 
647 	fc->fs_private = ctx;
648 	fc->ops = &afs_context_ops;
649 	return 0;
650 }
651 
652 /*
653  * Initialise an inode cache slab element prior to any use.  Note that
654  * afs_alloc_inode() *must* reset anything that could incorrectly leak from one
655  * inode to another.
656  */
657 static void afs_i_init_once(void *_vnode)
658 {
659 	struct afs_vnode *vnode = _vnode;
660 
661 	memset(vnode, 0, sizeof(*vnode));
662 	inode_init_once(&vnode->netfs.inode);
663 	mutex_init(&vnode->io_lock);
664 	init_rwsem(&vnode->validate_lock);
665 	spin_lock_init(&vnode->wb_lock);
666 	spin_lock_init(&vnode->lock);
667 	INIT_LIST_HEAD(&vnode->wb_keys);
668 	INIT_LIST_HEAD(&vnode->pending_locks);
669 	INIT_LIST_HEAD(&vnode->granted_locks);
670 	INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
671 	INIT_LIST_HEAD(&vnode->cb_mmap_link);
672 	seqlock_init(&vnode->cb_lock);
673 }
674 
675 /*
676  * allocate an AFS inode struct from our slab cache
677  */
678 static struct inode *afs_alloc_inode(struct super_block *sb)
679 {
680 	struct afs_vnode *vnode;
681 
682 	vnode = alloc_inode_sb(sb, afs_inode_cachep, GFP_KERNEL);
683 	if (!vnode)
684 		return NULL;
685 
686 	atomic_inc(&afs_count_active_inodes);
687 
688 	/* Reset anything that shouldn't leak from one inode to the next. */
689 	memset(&vnode->fid, 0, sizeof(vnode->fid));
690 	memset(&vnode->status, 0, sizeof(vnode->status));
691 	afs_vnode_set_cache(vnode, NULL);
692 
693 	vnode->volume		= NULL;
694 	vnode->lock_key		= NULL;
695 	vnode->permit_cache	= NULL;
696 
697 	vnode->flags		= 1 << AFS_VNODE_UNSET;
698 	vnode->lock_state	= AFS_VNODE_LOCK_NONE;
699 
700 	init_rwsem(&vnode->rmdir_lock);
701 	INIT_WORK(&vnode->cb_work, afs_invalidate_mmap_work);
702 
703 	_leave(" = %p", &vnode->netfs.inode);
704 	return &vnode->netfs.inode;
705 }
706 
707 static void afs_free_inode(struct inode *inode)
708 {
709 	kmem_cache_free(afs_inode_cachep, AFS_FS_I(inode));
710 }
711 
712 /*
713  * destroy an AFS inode struct
714  */
715 static void afs_destroy_inode(struct inode *inode)
716 {
717 	struct afs_vnode *vnode = AFS_FS_I(inode);
718 
719 	_enter("%p{%llx:%llu}", inode, vnode->fid.vid, vnode->fid.vnode);
720 
721 	_debug("DESTROY INODE %p", inode);
722 
723 	atomic_dec(&afs_count_active_inodes);
724 }
725 
726 static void afs_get_volume_status_success(struct afs_operation *op)
727 {
728 	struct afs_volume_status *vs = &op->volstatus.vs;
729 	struct kstatfs *buf = op->volstatus.buf;
730 
731 	if (vs->max_quota == 0)
732 		buf->f_blocks = vs->part_max_blocks;
733 	else
734 		buf->f_blocks = vs->max_quota;
735 
736 	if (buf->f_blocks > vs->blocks_in_use)
737 		buf->f_bavail = buf->f_bfree =
738 			buf->f_blocks - vs->blocks_in_use;
739 }
740 
741 static const struct afs_operation_ops afs_get_volume_status_operation = {
742 	.issue_afs_rpc	= afs_fs_get_volume_status,
743 	.issue_yfs_rpc	= yfs_fs_get_volume_status,
744 	.success	= afs_get_volume_status_success,
745 };
746 
747 /*
748  * return information about an AFS volume
749  */
750 static int afs_statfs(struct dentry *dentry, struct kstatfs *buf)
751 {
752 	struct afs_super_info *as = AFS_FS_S(dentry->d_sb);
753 	struct afs_operation *op;
754 	struct afs_vnode *vnode = AFS_FS_I(d_inode(dentry));
755 
756 	buf->f_type	= dentry->d_sb->s_magic;
757 	buf->f_bsize	= AFS_BLOCK_SIZE;
758 	buf->f_namelen	= AFSNAMEMAX - 1;
759 
760 	if (as->dyn_root) {
761 		buf->f_blocks	= 1;
762 		buf->f_bavail	= 0;
763 		buf->f_bfree	= 0;
764 		return 0;
765 	}
766 
767 	op = afs_alloc_operation(NULL, as->volume);
768 	if (IS_ERR(op))
769 		return PTR_ERR(op);
770 
771 	afs_op_set_vnode(op, 0, vnode);
772 	op->nr_files		= 1;
773 	op->volstatus.buf	= buf;
774 	op->ops			= &afs_get_volume_status_operation;
775 	return afs_do_sync_operation(op);
776 }
777