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/* NFS FS-Cache index structure definition
*
* 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 Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_fs_sb.h>
#include <linux/in6.h>
#include <linux/iversion.h>
#include "internal.h"
#include "fscache.h"
#define NFSDBG_FACILITY NFSDBG_FSCACHE
/*
* Define the NFS filesystem for FS-Cache. Upon registration FS-Cache sticks
* the cookie for the top-level index object for NFS into here. The top-level
* index can than have other cache objects inserted into it.
*/
struct fscache_netfs nfs_fscache_netfs = {
.name = "nfs",
.version = 0,
};
/*
* Register NFS for caching
*/
int nfs_fscache_register(void)
{
return fscache_register_netfs(&nfs_fscache_netfs);
}
/*
* Unregister NFS for caching
*/
void nfs_fscache_unregister(void)
{
fscache_unregister_netfs(&nfs_fscache_netfs);
}
/*
* Define the server object for FS-Cache. This is used to describe a server
* object to fscache_acquire_cookie(). It is keyed by the NFS protocol and
* server address parameters.
*/
const struct fscache_cookie_def nfs_fscache_server_index_def = {
.name = "NFS.server",
.type = FSCACHE_COOKIE_TYPE_INDEX,
};
/*
* Define the superblock object for FS-Cache. This is used to describe a
* superblock object to fscache_acquire_cookie(). It is keyed by all the NFS
* parameters that might cause a separate superblock.
*/
const struct fscache_cookie_def nfs_fscache_super_index_def = {
.name = "NFS.super",
.type = FSCACHE_COOKIE_TYPE_INDEX,
};
/*
* Get certain file attributes from the netfs data
* - This function can be absent for an index
* - Not permitted to return an error
* - The netfs data from the cookie being used as the source is presented
*/
static void nfs_fscache_inode_get_attr(const void *cookie_netfs_data,
uint64_t *size)
{
const struct nfs_inode *nfsi = cookie_netfs_data;
*size = nfsi->vfs_inode.i_size;
}
/*
* Consult the netfs about the state of an object
* - This function can be absent if the index carries no state data
* - The netfs data from the cookie being used as the target is
* presented, as is the auxiliary data
*/
static
enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
const void *data,
uint16_t datalen)
{
struct nfs_fscache_inode_auxdata auxdata;
struct nfs_inode *nfsi = cookie_netfs_data;
if (datalen != sizeof(auxdata))
return FSCACHE_CHECKAUX_OBSOLETE;
memset(&auxdata, 0, sizeof(auxdata));
auxdata.size = nfsi->vfs_inode.i_size;
auxdata.mtime = nfsi->vfs_inode.i_mtime;
auxdata.ctime = nfsi->vfs_inode.i_ctime;
if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
auxdata.change_attr = inode_peek_iversion_raw(&nfsi->vfs_inode);
if (memcmp(data, &auxdata, datalen) != 0)
return FSCACHE_CHECKAUX_OBSOLETE;
return FSCACHE_CHECKAUX_OKAY;
}
/*
* Get an extra reference on a read context.
* - This function can be absent if the completion function doesn't require a
* context.
* - The read context is passed back to NFS in the event that a data read on the
* cache fails with EIO - in which case the server must be contacted to
* retrieve the data, which requires the read context for security.
*/
static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
{
get_nfs_open_context(context);
}
/*
* Release an extra reference on a read context.
* - This function can be absent if the completion function doesn't require a
* context.
*/
static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
{
if (context)
put_nfs_open_context(context);
}
/*
* Define the inode object for FS-Cache. This is used to describe an inode
* object to fscache_acquire_cookie(). It is keyed by the NFS file handle for
* an inode.
*
* Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
* held in the cache auxiliary data for the data storage object with those in
* the inode struct in memory.
*/
const struct fscache_cookie_def nfs_fscache_inode_object_def = {
.name = "NFS.fh",
.type = FSCACHE_COOKIE_TYPE_DATAFILE,
.get_attr = nfs_fscache_inode_get_attr,
.check_aux = nfs_fscache_inode_check_aux,
.get_context = nfs_fh_get_context,
.put_context = nfs_fh_put_context,
};
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