linux/fs/afs/cache.c
David Howells ad6a942a9e afs: Update the cache index structure
Update the cache index structure in the following ways:

 (1) Don't use the volume name followed by the volume type as levels in the
     cache index.  Volumes can be renamed.  Use the volume ID instead.

 (2) Don't store the VLDB data for a volume in the tree.  If the volume
     database should be cached locally, then it should be done in a separate
     tree.

 (3) Expand the volume ID stored in the cache to 64 bits.

 (4) Expand the file/vnode ID stored in the cache to 96 bits.

 (5) Increment the cache structure version number to 1.

Signed-off-by: David Howells <dhowells@redhat.com>
2017-11-13 15:38:17 +00:00

207 lines
5.3 KiB
C

/* AFS caching stuff
*
* Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/sched.h>
#include "internal.h"
static uint16_t afs_cell_cache_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t buflen);
static uint16_t afs_volume_cache_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t buflen);
static uint16_t afs_vnode_cache_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t buflen);
static void afs_vnode_cache_get_attr(const void *cookie_netfs_data,
uint64_t *size);
static uint16_t afs_vnode_cache_get_aux(const void *cookie_netfs_data,
void *buffer, uint16_t buflen);
static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data,
const void *buffer,
uint16_t buflen);
struct fscache_netfs afs_cache_netfs = {
.name = "afs",
.version = 1,
};
struct fscache_cookie_def afs_cell_cache_index_def = {
.name = "AFS.cell",
.type = FSCACHE_COOKIE_TYPE_INDEX,
.get_key = afs_cell_cache_get_key,
};
struct fscache_cookie_def afs_volume_cache_index_def = {
.name = "AFS.volume",
.type = FSCACHE_COOKIE_TYPE_INDEX,
.get_key = afs_volume_cache_get_key,
};
struct fscache_cookie_def afs_vnode_cache_index_def = {
.name = "AFS.vnode",
.type = FSCACHE_COOKIE_TYPE_DATAFILE,
.get_key = afs_vnode_cache_get_key,
.get_attr = afs_vnode_cache_get_attr,
.get_aux = afs_vnode_cache_get_aux,
.check_aux = afs_vnode_cache_check_aux,
};
/*
* set the key for the index entry
*/
static uint16_t afs_cell_cache_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct afs_cell *cell = cookie_netfs_data;
uint16_t klen;
_enter("%p,%p,%u", cell, buffer, bufmax);
klen = strlen(cell->name);
if (klen > bufmax)
return 0;
memcpy(buffer, cell->name, klen);
return klen;
}
/*****************************************************************************/
/*
* set the key for the volume index entry
*/
static uint16_t afs_volume_cache_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct afs_volume *volume = cookie_netfs_data;
struct {
u64 volid;
} __packed key;
_enter("{%u},%p,%u", volume->type, buffer, bufmax);
if (bufmax < sizeof(key))
return 0;
key.volid = volume->vid;
memcpy(buffer, &key, sizeof(key));
return sizeof(key);
}
/*****************************************************************************/
/*
* set the key for the index entry
*/
static uint16_t afs_vnode_cache_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct afs_vnode *vnode = cookie_netfs_data;
struct {
u32 vnode_id[3];
} __packed key;
_enter("{%x,%x,%llx},%p,%u",
vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
buffer, bufmax);
/* Allow for a 96-bit key */
memset(&key, 0, sizeof(key));
key.vnode_id[0] = vnode->fid.vnode;
key.vnode_id[1] = 0;
key.vnode_id[2] = 0;
if (sizeof(key) > bufmax)
return 0;
memcpy(buffer, &key, sizeof(key));
return sizeof(key);
}
/*
* provide updated file attributes
*/
static void afs_vnode_cache_get_attr(const void *cookie_netfs_data,
uint64_t *size)
{
const struct afs_vnode *vnode = cookie_netfs_data;
_enter("{%x,%x,%llx},",
vnode->fid.vnode, vnode->fid.unique,
vnode->status.data_version);
*size = vnode->status.size;
}
struct afs_vnode_cache_aux {
u64 data_version;
u32 fid_unique;
} __packed;
/*
* provide new auxiliary cache data
*/
static uint16_t afs_vnode_cache_get_aux(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct afs_vnode *vnode = cookie_netfs_data;
struct afs_vnode_cache_aux aux;
_enter("{%x,%x,%Lx},%p,%u",
vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
buffer, bufmax);
memset(&aux, 0, sizeof(aux));
aux.data_version = vnode->status.data_version;
aux.fid_unique = vnode->fid.unique;
if (bufmax < sizeof(aux))
return 0;
memcpy(buffer, &aux, sizeof(aux));
return sizeof(aux);
}
/*
* check that the auxiliary data indicates that the entry is still valid
*/
static enum fscache_checkaux afs_vnode_cache_check_aux(void *cookie_netfs_data,
const void *buffer,
uint16_t buflen)
{
struct afs_vnode *vnode = cookie_netfs_data;
struct afs_vnode_cache_aux aux;
_enter("{%x,%x,%llx},%p,%u",
vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
buffer, buflen);
memcpy(&aux, buffer, sizeof(aux));
/* check the size of the data is what we're expecting */
if (buflen != sizeof(aux)) {
_leave(" = OBSOLETE [len %hx != %zx]", buflen, sizeof(aux));
return FSCACHE_CHECKAUX_OBSOLETE;
}
if (vnode->fid.unique != aux.fid_unique) {
_leave(" = OBSOLETE [uniq %x != %x]",
aux.fid_unique, vnode->fid.unique);
return FSCACHE_CHECKAUX_OBSOLETE;
}
if (vnode->status.data_version != aux.data_version) {
_leave(" = OBSOLETE [vers %llx != %llx]",
aux.data_version, vnode->status.data_version);
return FSCACHE_CHECKAUX_OBSOLETE;
}
_leave(" = SUCCESS");
return FSCACHE_CHECKAUX_OKAY;
}