32e150037d
Store the volume coherency data in an xattr and check it when we rebind the volume. If it doesn't match the cache volume is moved to the graveyard and rebuilt anew. Changes ======= ver #4: - Remove a couple of debugging prints. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/163967164397.1823006.2950539849831291830.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021563138.640689.15851092065380543119.stgit@warthog.procyon.org.uk/ # v4
140 lines
3.3 KiB
C
140 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/* Volume handling.
|
|
*
|
|
* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*/
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/slab.h>
|
|
#include "internal.h"
|
|
#include <trace/events/fscache.h>
|
|
|
|
/*
|
|
* Allocate and set up a volume representation. We make sure all the fanout
|
|
* directories are created and pinned.
|
|
*/
|
|
void cachefiles_acquire_volume(struct fscache_volume *vcookie)
|
|
{
|
|
struct cachefiles_volume *volume;
|
|
struct cachefiles_cache *cache = vcookie->cache->cache_priv;
|
|
const struct cred *saved_cred;
|
|
struct dentry *vdentry, *fan;
|
|
size_t len;
|
|
char *name;
|
|
bool is_new = false;
|
|
int ret, n_accesses, i;
|
|
|
|
_enter("");
|
|
|
|
volume = kzalloc(sizeof(struct cachefiles_volume), GFP_KERNEL);
|
|
if (!volume)
|
|
return;
|
|
volume->vcookie = vcookie;
|
|
volume->cache = cache;
|
|
INIT_LIST_HEAD(&volume->cache_link);
|
|
|
|
cachefiles_begin_secure(cache, &saved_cred);
|
|
|
|
len = vcookie->key[0];
|
|
name = kmalloc(len + 3, GFP_NOFS);
|
|
if (!name)
|
|
goto error_vol;
|
|
name[0] = 'I';
|
|
memcpy(name + 1, vcookie->key + 1, len);
|
|
name[len + 1] = 0;
|
|
|
|
retry:
|
|
vdentry = cachefiles_get_directory(cache, cache->store, name, &is_new);
|
|
if (IS_ERR(vdentry))
|
|
goto error_name;
|
|
volume->dentry = vdentry;
|
|
|
|
if (is_new) {
|
|
if (!cachefiles_set_volume_xattr(volume))
|
|
goto error_dir;
|
|
} else {
|
|
ret = cachefiles_check_volume_xattr(volume);
|
|
if (ret < 0) {
|
|
if (ret != -ESTALE)
|
|
goto error_dir;
|
|
inode_lock_nested(d_inode(cache->store), I_MUTEX_PARENT);
|
|
cachefiles_bury_object(cache, NULL, cache->store, vdentry,
|
|
FSCACHE_VOLUME_IS_WEIRD);
|
|
cachefiles_put_directory(volume->dentry);
|
|
cond_resched();
|
|
goto retry;
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < 256; i++) {
|
|
sprintf(name, "@%02x", i);
|
|
fan = cachefiles_get_directory(cache, vdentry, name, NULL);
|
|
if (IS_ERR(fan))
|
|
goto error_fan;
|
|
volume->fanout[i] = fan;
|
|
}
|
|
|
|
cachefiles_end_secure(cache, saved_cred);
|
|
|
|
vcookie->cache_priv = volume;
|
|
n_accesses = atomic_inc_return(&vcookie->n_accesses); /* Stop wakeups on dec-to-0 */
|
|
trace_fscache_access_volume(vcookie->debug_id, 0,
|
|
refcount_read(&vcookie->ref),
|
|
n_accesses, fscache_access_cache_pin);
|
|
|
|
spin_lock(&cache->object_list_lock);
|
|
list_add(&volume->cache_link, &volume->cache->volumes);
|
|
spin_unlock(&cache->object_list_lock);
|
|
|
|
kfree(name);
|
|
return;
|
|
|
|
error_fan:
|
|
for (i = 0; i < 256; i++)
|
|
cachefiles_put_directory(volume->fanout[i]);
|
|
error_dir:
|
|
cachefiles_put_directory(volume->dentry);
|
|
error_name:
|
|
kfree(name);
|
|
error_vol:
|
|
kfree(volume);
|
|
cachefiles_end_secure(cache, saved_cred);
|
|
}
|
|
|
|
/*
|
|
* Release a volume representation.
|
|
*/
|
|
static void __cachefiles_free_volume(struct cachefiles_volume *volume)
|
|
{
|
|
int i;
|
|
|
|
_enter("");
|
|
|
|
volume->vcookie->cache_priv = NULL;
|
|
|
|
for (i = 0; i < 256; i++)
|
|
cachefiles_put_directory(volume->fanout[i]);
|
|
cachefiles_put_directory(volume->dentry);
|
|
kfree(volume);
|
|
}
|
|
|
|
void cachefiles_free_volume(struct fscache_volume *vcookie)
|
|
{
|
|
struct cachefiles_volume *volume = vcookie->cache_priv;
|
|
|
|
if (volume) {
|
|
spin_lock(&volume->cache->object_list_lock);
|
|
list_del_init(&volume->cache_link);
|
|
spin_unlock(&volume->cache->object_list_lock);
|
|
__cachefiles_free_volume(volume);
|
|
}
|
|
}
|
|
|
|
void cachefiles_withdraw_volume(struct cachefiles_volume *volume)
|
|
{
|
|
fscache_withdraw_volume(volume->vcookie);
|
|
cachefiles_set_volume_xattr(volume);
|
|
__cachefiles_free_volume(volume);
|
|
}
|