mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
98 lines
2.9 KiB
98 lines
2.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* Filesystem index definition |
|
* |
|
* Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. |
|
* Written by David Howells ([email protected]) |
|
*/ |
|
|
|
#define FSCACHE_DEBUG_LEVEL CACHE |
|
#include <linux/module.h> |
|
#include "internal.h" |
|
|
|
static |
|
enum fscache_checkaux fscache_fsdef_netfs_check_aux(void *cookie_netfs_data, |
|
const void *data, |
|
uint16_t datalen, |
|
loff_t object_size); |
|
|
|
/* |
|
* The root index is owned by FS-Cache itself. |
|
* |
|
* When a netfs requests caching facilities, FS-Cache will, if one doesn't |
|
* already exist, create an entry in the root index with the key being the name |
|
* of the netfs ("AFS" for example), and the auxiliary data holding the index |
|
* structure version supplied by the netfs: |
|
* |
|
* FSDEF |
|
* | |
|
* +-----------+ |
|
* | | |
|
* NFS AFS |
|
* [v=1] [v=1] |
|
* |
|
* If an entry with the appropriate name does already exist, the version is |
|
* compared. If the version is different, the entire subtree from that entry |
|
* will be discarded and a new entry created. |
|
* |
|
* The new entry will be an index, and a cookie referring to it will be passed |
|
* to the netfs. This is then the root handle by which the netfs accesses the |
|
* cache. It can create whatever objects it likes in that index, including |
|
* further indices. |
|
*/ |
|
static struct fscache_cookie_def fscache_fsdef_index_def = { |
|
.name = ".FS-Cache", |
|
.type = FSCACHE_COOKIE_TYPE_INDEX, |
|
}; |
|
|
|
struct fscache_cookie fscache_fsdef_index = { |
|
.debug_id = 1, |
|
.ref = REFCOUNT_INIT(1), |
|
.n_active = ATOMIC_INIT(1), |
|
.lock = __SPIN_LOCK_UNLOCKED(fscache_fsdef_index.lock), |
|
.backing_objects = HLIST_HEAD_INIT, |
|
.def = &fscache_fsdef_index_def, |
|
.flags = 1 << FSCACHE_COOKIE_ENABLED, |
|
.type = FSCACHE_COOKIE_TYPE_INDEX, |
|
}; |
|
EXPORT_SYMBOL(fscache_fsdef_index); |
|
|
|
/* |
|
* Definition of an entry in the root index. Each entry is an index, keyed to |
|
* a specific netfs and only applicable to a particular version of the index |
|
* structure used by that netfs. |
|
*/ |
|
struct fscache_cookie_def fscache_fsdef_netfs_def = { |
|
.name = "FSDEF.netfs", |
|
.type = FSCACHE_COOKIE_TYPE_INDEX, |
|
.check_aux = fscache_fsdef_netfs_check_aux, |
|
}; |
|
|
|
/* |
|
* check that the index structure version number stored in the auxiliary data |
|
* matches the one the netfs gave us |
|
*/ |
|
static enum fscache_checkaux fscache_fsdef_netfs_check_aux( |
|
void *cookie_netfs_data, |
|
const void *data, |
|
uint16_t datalen, |
|
loff_t object_size) |
|
{ |
|
struct fscache_netfs *netfs = cookie_netfs_data; |
|
uint32_t version; |
|
|
|
_enter("{%s},,%hu", netfs->name, datalen); |
|
|
|
if (datalen != sizeof(version)) { |
|
_leave(" = OBSOLETE [dl=%d v=%zu]", datalen, sizeof(version)); |
|
return FSCACHE_CHECKAUX_OBSOLETE; |
|
} |
|
|
|
memcpy(&version, data, sizeof(version)); |
|
if (version != netfs->version) { |
|
_leave(" = OBSOLETE [ver=%x net=%x]", version, netfs->version); |
|
return FSCACHE_CHECKAUX_OBSOLETE; |
|
} |
|
|
|
_leave(" = OKAY"); |
|
return FSCACHE_CHECKAUX_OKAY; |
|
}
|
|
|