- 根目录:
- fs
- afs
- cache.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_cell_cache_get_aux(const void *cookie_netfs_data,
void *buffer, uint16_t buflen);
static enum fscache_checkaux afs_cell_cache_check_aux(void *cookie_netfs_data,
const void *buffer,
uint16_t buflen);
static uint16_t afs_vlocation_cache_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t buflen);
static uint16_t afs_vlocation_cache_get_aux(const void *cookie_netfs_data,
void *buffer, uint16_t buflen);
static enum fscache_checkaux afs_vlocation_cache_check_aux(
void *cookie_netfs_data, const 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);
static void afs_vnode_cache_now_uncached(void *cookie_netfs_data);
struct fscache_netfs afs_cache_netfs = {
.name = "afs",
.version = 0,
};
struct fscache_cookie_def afs_cell_cache_index_def = {
.name = "AFS.cell",
.type = FSCACHE_COOKIE_TYPE_INDEX,
.get_key = afs_cell_cache_get_key,
.get_aux = afs_cell_cache_get_aux,
.check_aux = afs_cell_cache_check_aux,
};
struct fscache_cookie_def afs_vlocation_cache_index_def = {
.name = "AFS.vldb",
.type = FSCACHE_COOKIE_TYPE_INDEX,
.get_key = afs_vlocation_cache_get_key,
.get_aux = afs_vlocation_cache_get_aux,
.check_aux = afs_vlocation_cache_check_aux,
};
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,
.now_uncached = afs_vnode_cache_now_uncached,
};
/*
* 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;
}
/*
* provide new auxiliary cache data
*/
static uint16_t afs_cell_cache_get_aux(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct afs_cell *cell = cookie_netfs_data;
uint16_t dlen;
_enter("%p,%p,%u", cell, buffer, bufmax);
dlen = cell->vl_naddrs * sizeof(cell->vl_addrs[0]);
dlen = min(dlen, bufmax);
dlen &= ~(sizeof(cell->vl_addrs[0]) - 1);
memcpy(buffer, cell->vl_addrs, dlen);
return dlen;
}
/*
* check that the auxiliary data indicates that the entry is still valid
*/
static enum fscache_checkaux afs_cell_cache_check_aux(void *cookie_netfs_data,
const void *buffer,
uint16_t buflen)
{
_leave(" = OKAY");
return FSCACHE_CHECKAUX_OKAY;
}
/*****************************************************************************/
/*
* set the key for the index entry
*/
static uint16_t afs_vlocation_cache_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct afs_vlocation *vlocation = cookie_netfs_data;
uint16_t klen;
_enter("{%s},%p,%u", vlocation->vldb.name, buffer, bufmax);
klen = strnlen(vlocation->vldb.name, sizeof(vlocation->vldb.name));
if (klen > bufmax)
return 0;
memcpy(buffer, vlocation->vldb.name, klen);
_leave(" = %u", klen);
return klen;
}
/*
* provide new auxiliary cache data
*/
static uint16_t afs_vlocation_cache_get_aux(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct afs_vlocation *vlocation = cookie_netfs_data;
uint16_t dlen;
_enter("{%s},%p,%u", vlocation->vldb.name, buffer, bufmax);
dlen = sizeof(struct afs_cache_vlocation);
dlen -= offsetof(struct afs_cache_vlocation, nservers);
if (dlen > bufmax)
return 0;
memcpy(buffer, (uint8_t *)&vlocation->vldb.nservers, dlen);
_leave(" = %u", dlen);
return dlen;
}
/*
* check that the auxiliary data indicates that the entry is still valid
*/
static
enum fscache_checkaux afs_vlocation_cache_check_aux(void *cookie_netfs_data,
const void *buffer,
uint16_t buflen)
{
const struct afs_cache_vlocation *cvldb;
struct afs_vlocation *vlocation = cookie_netfs_data;
uint16_t dlen;
_enter("{%s},%p,%u", vlocation->vldb.name, buffer, buflen);
/* check the size of the data is what we're expecting */
dlen = sizeof(struct afs_cache_vlocation);
dlen -= offsetof(struct afs_cache_vlocation, nservers);
if (dlen != buflen)
return FSCACHE_CHECKAUX_OBSOLETE;
cvldb = container_of(buffer, struct afs_cache_vlocation, nservers);
/* if what's on disk is more valid than what's in memory, then use the
* VL record from the cache */
if (!vlocation->valid || vlocation->vldb.rtime == cvldb->rtime) {
memcpy((uint8_t *)&vlocation->vldb.nservers, buffer, dlen);
vlocation->valid = 1;
_leave(" = SUCCESS [c->m]");
return FSCACHE_CHECKAUX_OKAY;
}
/* need to update the cache if the cached info differs */
if (memcmp(&vlocation->vldb, buffer, dlen) != 0) {
/* delete if the volume IDs for this name differ */
if (memcmp(&vlocation->vldb.vid, &cvldb->vid,
sizeof(cvldb->vid)) != 0
) {
_leave(" = OBSOLETE");
return FSCACHE_CHECKAUX_OBSOLETE;
}
_leave(" = UPDATE");
return FSCACHE_CHECKAUX_NEEDS_UPDATE;
}
_leave(" = OKAY");
return FSCACHE_CHECKAUX_OKAY;
}
/*****************************************************************************/
/*
* 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;
uint16_t klen;
_enter("{%u},%p,%u", volume->type, buffer, bufmax);
klen = sizeof(volume->type);
if (klen > bufmax)
return 0;
memcpy(buffer, &volume->type, sizeof(volume->type));
_leave(" = %u", klen);
return klen;
}
/*****************************************************************************/
/*
* 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;
uint16_t klen;
_enter("{%x,%x,%llx},%p,%u",
vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
buffer, bufmax);
klen = sizeof(vnode->fid.vnode);
if (klen > bufmax)
return 0;
memcpy(buffer, &vnode->fid.vnode, sizeof(vnode->fid.vnode));
_leave(" = %u", klen);
return klen;
}
/*
* 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;
}
/*
* 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;
uint16_t dlen;
_enter("{%x,%x,%Lx},%p,%u",
vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
buffer, bufmax);
dlen = sizeof(vnode->fid.unique) + sizeof(vnode->status.data_version);
if (dlen > bufmax)
return 0;
memcpy(buffer, &vnode->fid.unique, sizeof(vnode->fid.unique));
buffer += sizeof(vnode->fid.unique);
memcpy(buffer, &vnode->status.data_version,
sizeof(vnode->status.data_version));
_leave(" = %u", dlen);
return dlen;
}
/*
* 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;
uint16_t dlen;
_enter("{%x,%x,%llx},%p,%u",
vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version,
buffer, buflen);
/* check the size of the data is what we're expecting */
dlen = sizeof(vnode->fid.unique) + sizeof(vnode->status.data_version);
if (dlen != buflen) {
_leave(" = OBSOLETE [len %hx != %hx]", dlen, buflen);
return FSCACHE_CHECKAUX_OBSOLETE;
}
if (memcmp(buffer,
&vnode->fid.unique,
sizeof(vnode->fid.unique)
) != 0) {
unsigned unique;
memcpy(&unique, buffer, sizeof(unique));
_leave(" = OBSOLETE [uniq %x != %x]",
unique, vnode->fid.unique);
return FSCACHE_CHECKAUX_OBSOLETE;
}
if (memcmp(buffer + sizeof(vnode->fid.unique),
&vnode->status.data_version,
sizeof(vnode->status.data_version)
) != 0) {
afs_dataversion_t version;
memcpy(&version, buffer + sizeof(vnode->fid.unique),
sizeof(version));
_leave(" = OBSOLETE [vers %llx != %llx]",
version, vnode->status.data_version);
return FSCACHE_CHECKAUX_OBSOLETE;
}
_leave(" = SUCCESS");
return FSCACHE_CHECKAUX_OKAY;
}
/*
* indication the cookie is no longer uncached
* - this function is called when the backing store currently caching a cookie
* is removed
* - the netfs should use this to clean up any markers indicating cached pages
* - this is mandatory for any object that may have data
*/
static void afs_vnode_cache_now_uncached(void *cookie_netfs_data)
{
struct afs_vnode *vnode = cookie_netfs_data;
struct pagevec pvec;
pgoff_t first;
int loop, nr_pages;
_enter("{%x,%x,%Lx}",
vnode->fid.vnode, vnode->fid.unique, vnode->status.data_version);
pagevec_init(&pvec, 0);
first = 0;
for (;;) {
/* grab a bunch of pages to clean */
nr_pages = pagevec_lookup(&pvec, vnode->vfs_inode.i_mapping,
first,
PAGEVEC_SIZE - pagevec_count(&pvec));
if (!nr_pages)
break;
for (loop = 0; loop < nr_pages; loop++)
ClearPageFsCache(pvec.pages[loop]);
first = pvec.pages[nr_pages - 1]->index + 1;
pvec.nr = nr_pages;
pagevec_release(&pvec);
cond_resched();
}
_leave("");
}