linux-sg2042/fs/nfs/fscache-index.c

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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 "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);
}
/*
* Layout of the key for an NFS server cache object.
*/
struct nfs_server_key {
uint16_t nfsversion; /* NFS protocol version */
uint16_t family; /* address family */
uint16_t port; /* IP port */
union {
struct in_addr ipv4_addr; /* IPv4 address */
struct in6_addr ipv6_addr; /* IPv6 address */
} addr[0];
};
/*
* Generate a key to describe a server in the main NFS index
* - We return the length of the key, or 0 if we can't generate one
*/
static uint16_t nfs_server_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct nfs_client *clp = cookie_netfs_data;
const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
struct nfs_server_key *key = buffer;
uint16_t len = sizeof(struct nfs_server_key);
key->nfsversion = clp->rpc_ops->version;
key->family = clp->cl_addr.ss_family;
memset(key, 0, len);
switch (clp->cl_addr.ss_family) {
case AF_INET:
key->port = sin->sin_port;
key->addr[0].ipv4_addr = sin->sin_addr;
len += sizeof(key->addr[0].ipv4_addr);
break;
case AF_INET6:
key->port = sin6->sin6_port;
key->addr[0].ipv6_addr = sin6->sin6_addr;
len += sizeof(key->addr[0].ipv6_addr);
break;
default:
printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
clp->cl_addr.ss_family);
len = 0;
break;
}
return len;
}
/*
* 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,
.get_key = nfs_server_get_key,
};
NFS: Define and create superblock-level objects Define and create superblock-level cache index objects (as managed by nfs_server structs). Each superblock object is created in a server level index object and is itself an index into which inode-level objects are inserted. Ideally there would be one superblock-level object per server, and the former would be folded into the latter; however, since the "nosharecache" option exists this isn't possible. The superblock object key is a sequence consisting of: (1) Certain superblock s_flags. (2) Various connection parameters that serve to distinguish superblocks for sget(). (3) The volume FSID. (4) The security flavour. (5) The uniquifier length. (6) The uniquifier text. This is normally an empty string, unless the fsc=xyz mount option was used to explicitly specify a uniquifier. The key blob is of variable length, depending on the length of (6). The superblock object is given no coherency data to carry in the auxiliary data permitted by the cache. It is assumed that the superblock is always coherent. This patch also adds uniquification handling such that two otherwise identical superblocks, at least one of which is marked "nosharecache", won't end up trying to share the on-disk cache. It will be possible to manually provide a uniquifier through a mount option with a later patch to avoid the error otherwise produced. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
2009-04-03 23:42:42 +08:00
/*
* Generate a key to describe a superblock key in the main NFS index
*/
static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct nfs_fscache_key *key;
const struct nfs_server *nfss = cookie_netfs_data;
uint16_t len;
key = nfss->fscache_key;
len = sizeof(key->key) + key->key.uniq_len;
if (len > bufmax) {
len = 0;
} else {
memcpy(buffer, &key->key, sizeof(key->key));
memcpy(buffer + sizeof(key->key),
key->key.uniquifier, key->key.uniq_len);
}
return len;
}
/*
* 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_key = nfs_super_get_key,
};
/*
* Definition of the auxiliary data attached to NFS inode storage objects
* within the cache.
*
* The contents of this struct are recorded in the on-disk local cache in the
* auxiliary data attached to the data storage object backing an inode. This
* permits coherency to be managed when a new inode binds to an already extant
* cache object.
*/
struct nfs_fscache_inode_auxdata {
struct timespec mtime;
struct timespec ctime;
loff_t size;
u64 change_attr;
};
/*
* Generate a key to describe an NFS inode in an NFS server's index
*/
static uint16_t nfs_fscache_inode_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct nfs_inode *nfsi = cookie_netfs_data;
uint16_t nsize;
/* use the inode's NFS filehandle as the key */
nsize = nfsi->fh.size;
memcpy(buffer, nfsi->fh.data, nsize);
return nsize;
}
/*
* 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;
}
/*
* Get the auxiliary data from netfs data
* - This function can be absent if the index carries no state data
* - Should store the auxiliary data in the buffer
* - Should return the amount of amount stored
* - Not permitted to return an error
* - The netfs data from the cookie being used as the source is presented
*/
static uint16_t nfs_fscache_inode_get_aux(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
struct nfs_fscache_inode_auxdata auxdata;
const struct nfs_inode *nfsi = cookie_netfs_data;
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 = nfsi->change_attr;
if (bufmax > sizeof(auxdata))
bufmax = sizeof(auxdata);
memcpy(buffer, &auxdata, bufmax);
return bufmax;
}
/*
* 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 = nfsi->change_attr;
if (memcmp(data, &auxdata, datalen) != 0)
return FSCACHE_CHECKAUX_OBSOLETE;
return FSCACHE_CHECKAUX_OKAY;
}
/*
* Indication from FS-Cache that the cookie is no longer cached
* - 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 nfs_fscache_inode_now_uncached(void *cookie_netfs_data)
{
struct nfs_inode *nfsi = cookie_netfs_data;
struct pagevec pvec;
pgoff_t first;
int loop, nr_pages;
pagevec_init(&pvec, 0);
first = 0;
dprintk("NFS: nfs_inode_now_uncached: nfs_inode 0x%p\n", nfsi);
for (;;) {
/* grab a bunch of pages to unmark */
nr_pages = pagevec_lookup(&pvec,
nfsi->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();
}
}
/*
* 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_key = nfs_fscache_inode_get_key,
.get_attr = nfs_fscache_inode_get_attr,
.get_aux = nfs_fscache_inode_get_aux,
.check_aux = nfs_fscache_inode_check_aux,
.now_uncached = nfs_fscache_inode_now_uncached,
.get_context = nfs_fh_get_context,
.put_context = nfs_fh_put_context,
};