linux/fs/nfs/fscache.c
David Howells ef79c097bb NFS: Use local disk inode cache
Bind data storage objects in the local cache to NFS inodes.

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 16:42:43 +01:00

331 lines
8.6 KiB
C

/* NFS filesystem cache interface
*
* 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/seq_file.h>
#include "internal.h"
#include "fscache.h"
#define NFSDBG_FACILITY NFSDBG_FSCACHE
static struct rb_root nfs_fscache_keys = RB_ROOT;
static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
/*
* Get the per-client index cookie for an NFS client if the appropriate mount
* flag was set
* - We always try and get an index cookie for the client, but get filehandle
* cookies on a per-superblock basis, depending on the mount flags
*/
void nfs_fscache_get_client_cookie(struct nfs_client *clp)
{
/* create a cache index for looking up filehandles */
clp->fscache = fscache_acquire_cookie(nfs_fscache_netfs.primary_index,
&nfs_fscache_server_index_def,
clp);
dfprintk(FSCACHE, "NFS: get client cookie (0x%p/0x%p)\n",
clp, clp->fscache);
}
/*
* Dispose of a per-client cookie
*/
void nfs_fscache_release_client_cookie(struct nfs_client *clp)
{
dfprintk(FSCACHE, "NFS: releasing client cookie (0x%p/0x%p)\n",
clp, clp->fscache);
fscache_relinquish_cookie(clp->fscache, 0);
clp->fscache = NULL;
}
/*
* Get the cache cookie for an NFS superblock. We have to handle
* uniquification here because the cache doesn't do it for us.
*/
void nfs_fscache_get_super_cookie(struct super_block *sb,
struct nfs_parsed_mount_data *data)
{
struct nfs_fscache_key *key, *xkey;
struct nfs_server *nfss = NFS_SB(sb);
struct rb_node **p, *parent;
const char *uniq = data->fscache_uniq ?: "";
int diff, ulen;
ulen = strlen(uniq);
key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
if (!key)
return;
key->nfs_client = nfss->nfs_client;
key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
key->key.nfs_server.flags = nfss->flags;
key->key.nfs_server.rsize = nfss->rsize;
key->key.nfs_server.wsize = nfss->wsize;
key->key.nfs_server.acregmin = nfss->acregmin;
key->key.nfs_server.acregmax = nfss->acregmax;
key->key.nfs_server.acdirmin = nfss->acdirmin;
key->key.nfs_server.acdirmax = nfss->acdirmax;
key->key.nfs_server.fsid = nfss->fsid;
key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
key->key.uniq_len = ulen;
memcpy(key->key.uniquifier, uniq, ulen);
spin_lock(&nfs_fscache_keys_lock);
p = &nfs_fscache_keys.rb_node;
parent = NULL;
while (*p) {
parent = *p;
xkey = rb_entry(parent, struct nfs_fscache_key, node);
if (key->nfs_client < xkey->nfs_client)
goto go_left;
if (key->nfs_client > xkey->nfs_client)
goto go_right;
diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
if (diff < 0)
goto go_left;
if (diff > 0)
goto go_right;
if (key->key.uniq_len == 0)
goto non_unique;
diff = memcmp(key->key.uniquifier,
xkey->key.uniquifier,
key->key.uniq_len);
if (diff < 0)
goto go_left;
if (diff > 0)
goto go_right;
goto non_unique;
go_left:
p = &(*p)->rb_left;
continue;
go_right:
p = &(*p)->rb_right;
}
rb_link_node(&key->node, parent, p);
rb_insert_color(&key->node, &nfs_fscache_keys);
spin_unlock(&nfs_fscache_keys_lock);
nfss->fscache_key = key;
/* create a cache index for looking up filehandles */
nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
&nfs_fscache_super_index_def,
nfss);
dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
nfss, nfss->fscache);
return;
non_unique:
spin_unlock(&nfs_fscache_keys_lock);
kfree(key);
nfss->fscache_key = NULL;
nfss->fscache = NULL;
printk(KERN_WARNING "NFS:"
" Cache request denied due to non-unique superblock keys\n");
}
/*
* release a per-superblock cookie
*/
void nfs_fscache_release_super_cookie(struct super_block *sb)
{
struct nfs_server *nfss = NFS_SB(sb);
dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
nfss, nfss->fscache);
fscache_relinquish_cookie(nfss->fscache, 0);
nfss->fscache = NULL;
if (nfss->fscache_key) {
spin_lock(&nfs_fscache_keys_lock);
rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
spin_unlock(&nfs_fscache_keys_lock);
kfree(nfss->fscache_key);
nfss->fscache_key = NULL;
}
}
/*
* Initialise the per-inode cache cookie pointer for an NFS inode.
*/
void nfs_fscache_init_inode_cookie(struct inode *inode)
{
NFS_I(inode)->fscache = NULL;
if (S_ISREG(inode->i_mode))
set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
}
/*
* Get the per-inode cache cookie for an NFS inode.
*/
static void nfs_fscache_enable_inode_cookie(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct nfs_inode *nfsi = NFS_I(inode);
if (nfsi->fscache || !NFS_FSCACHE(inode))
return;
if ((NFS_SB(sb)->options & NFS_OPTION_FSCACHE)) {
nfsi->fscache = fscache_acquire_cookie(
NFS_SB(sb)->fscache,
&nfs_fscache_inode_object_def,
nfsi);
dfprintk(FSCACHE, "NFS: get FH cookie (0x%p/0x%p/0x%p)\n",
sb, nfsi, nfsi->fscache);
}
}
/*
* Release a per-inode cookie.
*/
void nfs_fscache_release_inode_cookie(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n",
nfsi, nfsi->fscache);
fscache_relinquish_cookie(nfsi->fscache, 0);
nfsi->fscache = NULL;
}
/*
* Retire a per-inode cookie, destroying the data attached to it.
*/
void nfs_fscache_zap_inode_cookie(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
dfprintk(FSCACHE, "NFS: zapping cookie (0x%p/0x%p)\n",
nfsi, nfsi->fscache);
fscache_relinquish_cookie(nfsi->fscache, 1);
nfsi->fscache = NULL;
}
/*
* Turn off the cache with regard to a per-inode cookie if opened for writing,
* invalidating all the pages in the page cache relating to the associated
* inode to clear the per-page caching.
*/
static void nfs_fscache_disable_inode_cookie(struct inode *inode)
{
clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
if (NFS_I(inode)->fscache) {
dfprintk(FSCACHE,
"NFS: nfsi 0x%p turning cache off\n", NFS_I(inode));
/* Need to invalidate any mapped pages that were read in before
* turning off the cache.
*/
if (inode->i_mapping && inode->i_mapping->nrpages)
invalidate_inode_pages2(inode->i_mapping);
nfs_fscache_zap_inode_cookie(inode);
}
}
/*
* wait_on_bit() sleep function for uninterruptible waiting
*/
static int nfs_fscache_wait_bit(void *flags)
{
schedule();
return 0;
}
/*
* Lock against someone else trying to also acquire or relinquish a cookie
*/
static inline void nfs_fscache_inode_lock(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
while (test_and_set_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags))
wait_on_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK,
nfs_fscache_wait_bit, TASK_UNINTERRUPTIBLE);
}
/*
* Unlock cookie management lock
*/
static inline void nfs_fscache_inode_unlock(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
smp_mb__before_clear_bit();
clear_bit(NFS_INO_FSCACHE_LOCK, &nfsi->flags);
smp_mb__after_clear_bit();
wake_up_bit(&nfsi->flags, NFS_INO_FSCACHE_LOCK);
}
/*
* Decide if we should enable or disable local caching for this inode.
* - For now, with NFS, only regular files that are open read-only will be able
* to use the cache.
* - May be invoked multiple times in parallel by parallel nfs_open() functions.
*/
void nfs_fscache_set_inode_cookie(struct inode *inode, struct file *filp)
{
if (NFS_FSCACHE(inode)) {
nfs_fscache_inode_lock(inode);
if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
nfs_fscache_disable_inode_cookie(inode);
else
nfs_fscache_enable_inode_cookie(inode);
nfs_fscache_inode_unlock(inode);
}
}
/*
* Replace a per-inode cookie due to revalidation detecting a file having
* changed on the server.
*/
void nfs_fscache_reset_inode_cookie(struct inode *inode)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct nfs_server *nfss = NFS_SERVER(inode);
struct fscache_cookie *old = nfsi->fscache;
nfs_fscache_inode_lock(inode);
if (nfsi->fscache) {
/* retire the current fscache cache and get a new one */
fscache_relinquish_cookie(nfsi->fscache, 1);
nfsi->fscache = fscache_acquire_cookie(
nfss->nfs_client->fscache,
&nfs_fscache_inode_object_def,
nfsi);
dfprintk(FSCACHE,
"NFS: revalidation new cookie (0x%p/0x%p/0x%p/0x%p)\n",
nfss, nfsi, old, nfsi->fscache);
}
nfs_fscache_inode_unlock(inode);
}