[linux-block.git] / fs / cachefiles / cache.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* Manage high-level VFS aspects of a cache.
 *
 * Copyright (C) 2007, 2021 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#include <linux/slab.h>
#include <linux/statfs.h>
#include <linux/namei.h>
#include "internal.h"

/*
 * Bring a cache online.
 */
int cachefiles_add_cache(struct cachefiles_cache *cache)
{
	struct fscache_cache *cache_cookie;
	struct path path;
	struct kstatfs stats;
	struct dentry *graveyard, *cachedir, *root;
	const struct cred *saved_cred;
	int ret;

	_enter("");

	cache_cookie = fscache_acquire_cache(cache->tag);
	if (IS_ERR(cache_cookie))
		return PTR_ERR(cache_cookie);

	/* we want to work under the module's security ID */
	ret = cachefiles_get_security_ID(cache);
	if (ret < 0)
		goto error_getsec;

	cachefiles_begin_secure(cache, &saved_cred);

	/* look up the directory at the root of the cache */
	ret = kern_path(cache->rootdirname, LOOKUP_DIRECTORY, &path);
	if (ret < 0)
		goto error_open_root;

	cache->mnt = path.mnt;
	root = path.dentry;

	ret = -EINVAL;
	if (is_idmapped_mnt(path.mnt)) {
		pr_warn("File cache on idmapped mounts not supported");
		goto error_unsupported;
	}

	/* check parameters */
	ret = -EOPNOTSUPP;
	if (d_is_negative(root) ||
	    !d_backing_inode(root)->i_op->lookup ||
	    !d_backing_inode(root)->i_op->mkdir ||
	    !(d_backing_inode(root)->i_opflags & IOP_XATTR) ||
	    !root->d_sb->s_op->statfs ||
	    !root->d_sb->s_op->sync_fs ||
	    root->d_sb->s_blocksize > PAGE_SIZE)
		goto error_unsupported;

	ret = -EROFS;
	if (sb_rdonly(root->d_sb))
		goto error_unsupported;

	/* determine the security of the on-disk cache as this governs
	 * security ID of files we create */
	ret = cachefiles_determine_cache_security(cache, root, &saved_cred);
	if (ret < 0)
		goto error_unsupported;

	/* get the cache size and blocksize */
	ret = vfs_statfs(&path, &stats);
	if (ret < 0)
		goto error_unsupported;

	ret = -ERANGE;
	if (stats.f_bsize <= 0)
		goto error_unsupported;

	ret = -EOPNOTSUPP;
	if (stats.f_bsize > PAGE_SIZE)
		goto error_unsupported;

	cache->bsize = stats.f_bsize;
	cache->bshift = 0;
	if (stats.f_bsize < PAGE_SIZE)
		cache->bshift = PAGE_SHIFT - ilog2(stats.f_bsize);

	_debug("blksize %u (shift %u)",
	       cache->bsize, cache->bshift);

	_debug("size %llu, avail %llu",
	       (unsigned long long) stats.f_blocks,
	       (unsigned long long) stats.f_bavail);

	/* set up caching limits */
	do_div(stats.f_files, 100);
	cache->fstop = stats.f_files * cache->fstop_percent;
	cache->fcull = stats.f_files * cache->fcull_percent;
	cache->frun  = stats.f_files * cache->frun_percent;

	_debug("limits {%llu,%llu,%llu} files",
	       (unsigned long long) cache->frun,
	       (unsigned long long) cache->fcull,
	       (unsigned long long) cache->fstop);

	stats.f_blocks >>= cache->bshift;
	do_div(stats.f_blocks, 100);
	cache->bstop = stats.f_blocks * cache->bstop_percent;
	cache->bcull = stats.f_blocks * cache->bcull_percent;
	cache->brun  = stats.f_blocks * cache->brun_percent;

	_debug("limits {%llu,%llu,%llu} blocks",
	       (unsigned long long) cache->brun,
	       (unsigned long long) cache->bcull,
	       (unsigned long long) cache->bstop);

	/* get the cache directory and check its type */
	cachedir = cachefiles_get_directory(cache, root, "cache", NULL);
	if (IS_ERR(cachedir)) {
		ret = PTR_ERR(cachedir);
		goto error_unsupported;
	}

	cache->store = cachedir;

	/* get the graveyard directory */
	graveyard = cachefiles_get_directory(cache, root, "graveyard", NULL);
	if (IS_ERR(graveyard)) {
		ret = PTR_ERR(graveyard);
		goto error_unsupported;
	}

	cache->graveyard = graveyard;
	cache->cache = cache_cookie;

	ret = fscache_add_cache(cache_cookie, &cachefiles_cache_ops, cache);
	if (ret < 0)
		goto error_add_cache;

	/* done */
	set_bit(CACHEFILES_READY, &cache->flags);
	dput(root);

	pr_info("File cache on %s registered\n", cache_cookie->name);

	/* check how much space the cache has */
	cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check);
	cachefiles_end_secure(cache, saved_cred);
	_leave(" = 0 [%px]", cache->cache);
	return 0;

error_add_cache:
	cachefiles_put_directory(cache->graveyard);
	cache->graveyard = NULL;
error_unsupported:
	cachefiles_put_directory(cache->store);
	cache->store = NULL;
	mntput(cache->mnt);
	cache->mnt = NULL;
	dput(root);
error_open_root:
	cachefiles_end_secure(cache, saved_cred);
error_getsec:
	fscache_relinquish_cache(cache_cookie);
	cache->cache = NULL;
	pr_err("Failed to register: %d\n", ret);
	return ret;
}

/*
 * See if we have space for a number of pages and/or a number of files in the
 * cache
 */
int cachefiles_has_space(struct cachefiles_cache *cache,
			 unsigned fnr, unsigned bnr,
			 enum cachefiles_has_space_for reason)
{
	struct kstatfs stats;
	u64 b_avail, b_writing;
	int ret;

	struct path path = {
		.mnt	= cache->mnt,
		.dentry	= cache->mnt->mnt_root,
	};

	//_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u",
	//       (unsigned long long) cache->frun,
	//       (unsigned long long) cache->fcull,
	//       (unsigned long long) cache->fstop,
	//       (unsigned long long) cache->brun,
	//       (unsigned long long) cache->bcull,
	//       (unsigned long long) cache->bstop,
	//       fnr, bnr);

	/* find out how many pages of blockdev are available */
	memset(&stats, 0, sizeof(stats));

	ret = vfs_statfs(&path, &stats);
	if (ret < 0) {
		trace_cachefiles_vfs_error(NULL, d_inode(path.dentry), ret,
					   cachefiles_trace_statfs_error);
		if (ret == -EIO)
			cachefiles_io_error(cache, "statfs failed");
		_leave(" = %d", ret);
		return ret;
	}

	b_avail = stats.f_bavail >> cache->bshift;
	b_writing = atomic_long_read(&cache->b_writing);
	if (b_avail > b_writing)
		b_avail -= b_writing;
	else
		b_avail = 0;

	//_debug("avail %llu,%llu",
	//       (unsigned long long)stats.f_ffree,
	//       (unsigned long long)b_avail);

	/* see if there is sufficient space */
	if (stats.f_ffree > fnr)
		stats.f_ffree -= fnr;
	else
		stats.f_ffree = 0;

	if (b_avail > bnr)
		b_avail -= bnr;
	else
		b_avail = 0;

	ret = -ENOBUFS;
	if (stats.f_ffree < cache->fstop ||
	    b_avail < cache->bstop)
		goto stop_and_begin_cull;

	ret = 0;
	if (stats.f_ffree < cache->fcull ||
	    b_avail < cache->bcull)
		goto begin_cull;

	if (test_bit(CACHEFILES_CULLING, &cache->flags) &&
	    stats.f_ffree >= cache->frun &&
	    b_avail >= cache->brun &&
	    test_and_clear_bit(CACHEFILES_CULLING, &cache->flags)
	    ) {
		_debug("cease culling");
		cachefiles_state_changed(cache);
	}

	//_leave(" = 0");
	return 0;

stop_and_begin_cull:
	switch (reason) {
	case cachefiles_has_space_for_write:
		fscache_count_no_write_space();
		break;
	case cachefiles_has_space_for_create:
		fscache_count_no_create_space();
		break;
	default:
		break;
	}
begin_cull:
	if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
		_debug("### CULL CACHE ###");
		cachefiles_state_changed(cache);
	}

	_leave(" = %d", ret);
	return ret;
}

/*
 * Mark all the objects as being out of service and queue them all for cleanup.
 */
static void cachefiles_withdraw_objects(struct cachefiles_cache *cache)
{
	struct cachefiles_object *object;
	unsigned int count = 0;

	_enter("");

	spin_lock(&cache->object_list_lock);

	while (!list_empty(&cache->object_list)) {
		object = list_first_entry(&cache->object_list,
					  struct cachefiles_object, cache_link);
		cachefiles_see_object(object, cachefiles_obj_see_withdrawal);
		list_del_init(&object->cache_link);
		fscache_withdraw_cookie(object->cookie);
		count++;
		if ((count & 63) == 0) {
			spin_unlock(&cache->object_list_lock);
			cond_resched();
			spin_lock(&cache->object_list_lock);
		}
	}

	spin_unlock(&cache->object_list_lock);
	_leave(" [%u objs]", count);
}

/*
 * Withdraw volumes.
 */
static void cachefiles_withdraw_volumes(struct cachefiles_cache *cache)
{
	_enter("");

	for (;;) {
		struct cachefiles_volume *volume = NULL;

		spin_lock(&cache->object_list_lock);
		if (!list_empty(&cache->volumes)) {
			volume = list_first_entry(&cache->volumes,
						  struct cachefiles_volume, cache_link);
			list_del_init(&volume->cache_link);
		}
		spin_unlock(&cache->object_list_lock);
		if (!volume)
			break;

		cachefiles_withdraw_volume(volume);
	}

	_leave("");
}

/*
 * Sync a cache to backing disk.
 */
static void cachefiles_sync_cache(struct cachefiles_cache *cache)
{
	const struct cred *saved_cred;
	int ret;

	_enter("%s", cache->cache->name);

	/* make sure all pages pinned by operations on behalf of the netfs are
	 * written to disc */
	cachefiles_begin_secure(cache, &saved_cred);
	down_read(&cache->mnt->mnt_sb->s_umount);
	ret = sync_filesystem(cache->mnt->mnt_sb);
	up_read(&cache->mnt->mnt_sb->s_umount);
	cachefiles_end_secure(cache, saved_cred);

	if (ret == -EIO)
		cachefiles_io_error(cache,
				    "Attempt to sync backing fs superblock returned error %d",
				    ret);
}

/*
 * Withdraw cache objects.
 */
void cachefiles_withdraw_cache(struct cachefiles_cache *cache)
{
	struct fscache_cache *fscache = cache->cache;

	pr_info("File cache on %s unregistering\n", fscache->name);

	fscache_withdraw_cache(fscache);

	/* we now have to destroy all the active objects pertaining to this
	 * cache - which we do by passing them off to thread pool to be
	 * disposed of */
	cachefiles_withdraw_objects(cache);
	fscache_wait_for_objects(fscache);

	cachefiles_withdraw_volumes(cache);
	cachefiles_sync_cache(cache);
	cache->cache = NULL;
	fscache_relinquish_cache(fscache);
}
Commit	Line	Data
80f94f29 DH	1	// SPDX-License-Identifier: GPL-2.0-or-later
	2	/* Manage high-level VFS aspects of a cache.
	3	*
	4	* Copyright (C) 2007, 2021 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
	6	*/
	7
	8	#include <linux/slab.h>
	9	#include <linux/statfs.h>
	10	#include <linux/namei.h>
	11	#include "internal.h"
	12
d1065b0a DH	13	/*
	14	* Bring a cache online.
	15	*/
	16	int cachefiles_add_cache(struct cachefiles_cache *cache)
	17	{
	18	struct fscache_cache *cache_cookie;
	19	struct path path;
	20	struct kstatfs stats;
	21	struct dentry graveyard, cachedir, *root;
	22	const struct cred *saved_cred;
	23	int ret;
	24
	25	_enter("");
	26
	27	cache_cookie = fscache_acquire_cache(cache->tag);
	28	if (IS_ERR(cache_cookie))
	29	return PTR_ERR(cache_cookie);
	30
	31	/* we want to work under the module's security ID */
	32	ret = cachefiles_get_security_ID(cache);
	33	if (ret < 0)
	34	goto error_getsec;
	35
	36	cachefiles_begin_secure(cache, &saved_cred);
	37
	38	/* look up the directory at the root of the cache */
	39	ret = kern_path(cache->rootdirname, LOOKUP_DIRECTORY, &path);
	40	if (ret < 0)
	41	goto error_open_root;
	42
	43	cache->mnt = path.mnt;
	44	root = path.dentry;
	45
	46	ret = -EINVAL;
8834147f	47	if (is_idmapped_mnt(path.mnt)) {
d1065b0a DH	48	pr_warn("File cache on idmapped mounts not supported");
	49	goto error_unsupported;
	50	}
	51
	52	/* check parameters */
	53	ret = -EOPNOTSUPP;
	54	if (d_is_negative(root) \|\|
	55	!d_backing_inode(root)->i_op->lookup \|\|
	56	!d_backing_inode(root)->i_op->mkdir \|\|
	57	!(d_backing_inode(root)->i_opflags & IOP_XATTR) \|\|
	58	!root->d_sb->s_op->statfs \|\|
	59	!root->d_sb->s_op->sync_fs \|\|
	60	root->d_sb->s_blocksize > PAGE_SIZE)
	61	goto error_unsupported;
	62
	63	ret = -EROFS;
	64	if (sb_rdonly(root->d_sb))
	65	goto error_unsupported;
	66
	67	/* determine the security of the on-disk cache as this governs
	68	* security ID of files we create */
	69	ret = cachefiles_determine_cache_security(cache, root, &saved_cred);
	70	if (ret < 0)
	71	goto error_unsupported;
	72
	73	/* get the cache size and blocksize */
	74	ret = vfs_statfs(&path, &stats);
	75	if (ret < 0)
	76	goto error_unsupported;
	77
	78	ret = -ERANGE;
	79	if (stats.f_bsize <= 0)
	80	goto error_unsupported;
	81
	82	ret = -EOPNOTSUPP;
	83	if (stats.f_bsize > PAGE_SIZE)
	84	goto error_unsupported;
	85
	86	cache->bsize = stats.f_bsize;
	87	cache->bshift = 0;
	88	if (stats.f_bsize < PAGE_SIZE)
	89	cache->bshift = PAGE_SHIFT - ilog2(stats.f_bsize);
	90
	91	_debug("blksize %u (shift %u)",
	92	cache->bsize, cache->bshift);
	93
	94	_debug("size %llu, avail %llu",
	95	(unsigned long long) stats.f_blocks,
	96	(unsigned long long) stats.f_bavail);
	97
	98	/* set up caching limits */
	99	do_div(stats.f_files, 100);
	100	cache->fstop = stats.f_files * cache->fstop_percent;
	101	cache->fcull = stats.f_files * cache->fcull_percent;
	102	cache->frun = stats.f_files * cache->frun_percent;
	103
	104	_debug("limits {%llu,%llu,%llu} files",
	105	(unsigned long long) cache->frun,
	106	(unsigned long long) cache->fcull,
	107	(unsigned long long) cache->fstop);
	108
	109	stats.f_blocks >>= cache->bshift;
	110	do_div(stats.f_blocks, 100);
	111	cache->bstop = stats.f_blocks * cache->bstop_percent;
112	cache->bcull = stats.f_blocks * cache->bcull_percent;
113	cache->brun = stats.f_blocks * cache->brun_percent;
114
115	_debug("limits {%llu,%llu,%llu} blocks",
116	(unsigned long long) cache->brun,
117	(unsigned long long) cache->bcull,
118	(unsigned long long) cache->bstop);
119
120	/* get the cache directory and check its type */
121	cachedir = cachefiles_get_directory(cache, root, "cache", NULL);
122	if (IS_ERR(cachedir)) {
123	ret = PTR_ERR(cachedir);
124	goto error_unsupported;
125	}
126
127	cache->store = cachedir;
128
129	/* get the graveyard directory */
130	graveyard = cachefiles_get_directory(cache, root, "graveyard", NULL);
131	if (IS_ERR(graveyard)) {
132	ret = PTR_ERR(graveyard);
133	goto error_unsupported;
134	}
135
136	cache->graveyard = graveyard;
137	cache->cache = cache_cookie;
138
139	ret = fscache_add_cache(cache_cookie, &cachefiles_cache_ops, cache);
140	if (ret < 0)
141	goto error_add_cache;
142
143	/* done */
144	set_bit(CACHEFILES_READY, &cache->flags);
145	dput(root);
146
147	pr_info("File cache on %s registered\n", cache_cookie->name);
148
149	/* check how much space the cache has */
3929eca7	150	cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check);
d1065b0a DH	151	cachefiles_end_secure(cache, saved_cred);
	152	_leave(" = 0 [%px]", cache->cache);
	153	return 0;
	154
	155	error_add_cache:
	156	cachefiles_put_directory(cache->graveyard);
	157	cache->graveyard = NULL;
	158	error_unsupported:
	159	cachefiles_put_directory(cache->store);
	160	cache->store = NULL;
	161	mntput(cache->mnt);
	162	cache->mnt = NULL;
	163	dput(root);
	164	error_open_root:
	165	cachefiles_end_secure(cache, saved_cred);
	166	error_getsec:
	167	fscache_relinquish_cache(cache_cookie);
	168	cache->cache = NULL;
	169	pr_err("Failed to register: %d\n", ret);
	170	return ret;
	171	}
	172
80f94f29 DH	173	/*
	174	* See if we have space for a number of pages and/or a number of files in the
	175	* cache
	176	*/
	177	int cachefiles_has_space(struct cachefiles_cache *cache,
3929eca7 DH	178	unsigned fnr, unsigned bnr,
3929eca7 DH	179	enum cachefiles_has_space_for reason)
80f94f29 DH	180	{
	181	struct kstatfs stats;
	182	u64 b_avail, b_writing;
	183	int ret;
	184
	185	struct path path = {
	186	.mnt = cache->mnt,
	187	.dentry = cache->mnt->mnt_root,
	188	};
	189
	190	//_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u",
	191	// (unsigned long long) cache->frun,
	192	// (unsigned long long) cache->fcull,
	193	// (unsigned long long) cache->fstop,
	194	// (unsigned long long) cache->brun,
	195	// (unsigned long long) cache->bcull,
	196	// (unsigned long long) cache->bstop,
	197	// fnr, bnr);
	198
	199	/* find out how many pages of blockdev are available */
	200	memset(&stats, 0, sizeof(stats));
	201
	202	ret = vfs_statfs(&path, &stats);
	203	if (ret < 0) {
	204	trace_cachefiles_vfs_error(NULL, d_inode(path.dentry), ret,
	205	cachefiles_trace_statfs_error);
	206	if (ret == -EIO)
	207	cachefiles_io_error(cache, "statfs failed");
	208	_leave(" = %d", ret);
	209	return ret;
	210	}
	211
	212	b_avail = stats.f_bavail >> cache->bshift;
	213	b_writing = atomic_long_read(&cache->b_writing);
	214	if (b_avail > b_writing)
	215	b_avail -= b_writing;
	216	else
	217	b_avail = 0;
	218
	219	//_debug("avail %llu,%llu",
	220	// (unsigned long long)stats.f_ffree,
	221	// (unsigned long long)b_avail);
	222
	223	/* see if there is sufficient space */
	224	if (stats.f_ffree > fnr)
	225	stats.f_ffree -= fnr;
	226	else
	227	stats.f_ffree = 0;
	228
	229	if (b_avail > bnr)
	230	b_avail -= bnr;
	231	else
	232	b_avail = 0;
	233
	234	ret = -ENOBUFS;
	235	if (stats.f_ffree < cache->fstop \|\|
	236	b_avail < cache->bstop)
3929eca7	237	goto stop_and_begin_cull;
80f94f29 DH	238
	239	ret = 0;
	240	if (stats.f_ffree < cache->fcull \|\|
	241	b_avail < cache->bcull)
	242	goto begin_cull;
	243
	244	if (test_bit(CACHEFILES_CULLING, &cache->flags) &&
	245	stats.f_ffree >= cache->frun &&
	246	b_avail >= cache->brun &&
	247	test_and_clear_bit(CACHEFILES_CULLING, &cache->flags)
	248	) {
	249	_debug("cease culling");
	250	cachefiles_state_changed(cache);
	251	}
	252
	253	//_leave(" = 0");
	254	return 0;
	255
3929eca7 DH	256	stop_and_begin_cull:
	257	switch (reason) {
	258	case cachefiles_has_space_for_write:
	259	fscache_count_no_write_space();
	260	break;
	261	case cachefiles_has_space_for_create:
	262	fscache_count_no_create_space();
	263	break;
	264	default:
	265	break;
	266	}
80f94f29 DH	267	begin_cull:
	268	if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
	269	_debug("### CULL CACHE ###");
	270	cachefiles_state_changed(cache);
	271	}
	272
	273	_leave(" = %d", ret);
	274	return ret;
	275	}
d1065b0a	276
1f08c925 DH	277	/*
	278	* Mark all the objects as being out of service and queue them all for cleanup.
	279	*/
	280	static void cachefiles_withdraw_objects(struct cachefiles_cache *cache)
	281	{
	282	struct cachefiles_object *object;
	283	unsigned int count = 0;
	284
	285	_enter("");
	286
	287	spin_lock(&cache->object_list_lock);
	288
	289	while (!list_empty(&cache->object_list)) {
	290	object = list_first_entry(&cache->object_list,
	291	struct cachefiles_object, cache_link);
	292	cachefiles_see_object(object, cachefiles_obj_see_withdrawal);
	293	list_del_init(&object->cache_link);
	294	fscache_withdraw_cookie(object->cookie);
	295	count++;
	296	if ((count & 63) == 0) {
	297	spin_unlock(&cache->object_list_lock);
	298	cond_resched();
	299	spin_lock(&cache->object_list_lock);
	300	}
	301	}
	302
	303	spin_unlock(&cache->object_list_lock);
	304	_leave(" [%u objs]", count);
	305	}
	306
fe2140e2 DH	307	/*
	308	* Withdraw volumes.
	309	*/
	310	static void cachefiles_withdraw_volumes(struct cachefiles_cache *cache)
	311	{
	312	_enter("");
	313
	314	for (;;) {
	315	struct cachefiles_volume *volume = NULL;
	316
	317	spin_lock(&cache->object_list_lock);
	318	if (!list_empty(&cache->volumes)) {
	319	volume = list_first_entry(&cache->volumes,
	320	struct cachefiles_volume, cache_link);
	321	list_del_init(&volume->cache_link);
	322	}
	323	spin_unlock(&cache->object_list_lock);
	324	if (!volume)
	325	break;
	326
	327	cachefiles_withdraw_volume(volume);
	328	}
	329
	330	_leave("");
	331	}
	332
d1065b0a DH	333	/*
	334	* Sync a cache to backing disk.
	335	*/
	336	static void cachefiles_sync_cache(struct cachefiles_cache *cache)
	337	{
	338	const struct cred *saved_cred;
	339	int ret;
	340
	341	_enter("%s", cache->cache->name);
	342
	343	/* make sure all pages pinned by operations on behalf of the netfs are
	344	* written to disc */
	345	cachefiles_begin_secure(cache, &saved_cred);
	346	down_read(&cache->mnt->mnt_sb->s_umount);
	347	ret = sync_filesystem(cache->mnt->mnt_sb);
	348	up_read(&cache->mnt->mnt_sb->s_umount);
	349	cachefiles_end_secure(cache, saved_cred);
	350
	351	if (ret == -EIO)
	352	cachefiles_io_error(cache,
	353	"Attempt to sync backing fs superblock returned error %d",
	354	ret);
	355	}
	356
	357	/*
	358	* Withdraw cache objects.
	359	*/
	360	void cachefiles_withdraw_cache(struct cachefiles_cache *cache)
	361	{
	362	struct fscache_cache *fscache = cache->cache;
	363
	364	pr_info("File cache on %s unregistering\n", fscache->name);
	365
	366	fscache_withdraw_cache(fscache);
	367
	368	/* we now have to destroy all the active objects pertaining to this
	369	* cache - which we do by passing them off to thread pool to be
	370	* disposed of */
1f08c925	371	cachefiles_withdraw_objects(cache);
d1065b0a DH	372	fscache_wait_for_objects(fscache);
d1065b0a DH	373
fe2140e2	374	cachefiles_withdraw_volumes(cache);
d1065b0a DH	375	cachefiles_sync_cache(cache);
	376	cache->cache = NULL;
	377	fscache_relinquish_cache(fscache);
	378	}