linux/fs/xfs/linux-2.6/xfs_export.c
David Chinner da353b0d64 [XFS] Radix tree based inode caching
One of the perpetual scaling problems XFS has is indexing it's incore
inodes. We currently uses hashes and the default hash sizes chosen can
only ever be a tradeoff between memory consumption and the maximum
realistic size of the cache.

As a result, anyone who has millions of inodes cached on a filesystem
needs to tunes the size of the cache via the ihashsize mount option to
allow decent scalability with inode cache operations.

A further problem is the separate inode cluster hash, whose size is based
on the ihashsize but is smaller, and so under certain conditions (sparse
cluster cache population) this can become a limitation long before the
inode hash is causing issues.

The following patchset removes the inode hash and cluster hash and
replaces them with radix trees to avoid the scalability limitations of the
hashes. It also reduces the size of the inodes by 3 pointers....

SGI-PV: 969561
SGI-Modid: xfs-linux-melb:xfs-kern:29481a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Tim Shimmin <tes@sgi.com>
2007-10-15 16:50:50 +10:00

187 lines
4.7 KiB
C

/*
* Copyright (c) 2004-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* 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.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_types.h"
#include "xfs_inum.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_export.h"
static struct dentry dotdot = { .d_name.name = "..", .d_name.len = 2, };
/*
* XFS encodes and decodes the fileid portion of NFS filehandles
* itself instead of letting the generic NFS code do it. This
* allows filesystems with 64 bit inode numbers to be exported.
*
* Note that a side effect is that xfs_vget() won't be passed a
* zero inode/generation pair under normal circumstances. As
* however a malicious client could send us such data, the check
* remains in that code.
*/
STATIC struct dentry *
xfs_fs_decode_fh(
struct super_block *sb,
__u32 *fh,
int fh_len,
int fileid_type,
int (*acceptable)(
void *context,
struct dentry *de),
void *context)
{
xfs_fid2_t ifid;
xfs_fid2_t pfid;
void *parent = NULL;
int is64 = 0;
__u32 *p = fh;
#if XFS_BIG_INUMS
is64 = (fileid_type & XFS_FILEID_TYPE_64FLAG);
fileid_type &= ~XFS_FILEID_TYPE_64FLAG;
#endif
/*
* Note that we only accept fileids which are long enough
* rather than allow the parent generation number to default
* to zero. XFS considers zero a valid generation number not
* an invalid/wildcard value. There's little point printk'ing
* a warning here as we don't have the client information
* which would make such a warning useful.
*/
if (fileid_type > 2 ||
fh_len < xfs_fileid_length((fileid_type == 2), is64))
return NULL;
p = xfs_fileid_decode_fid2(p, &ifid, is64);
if (fileid_type == 2) {
p = xfs_fileid_decode_fid2(p, &pfid, is64);
parent = &pfid;
}
fh = (__u32 *)&ifid;
return sb->s_export_op->find_exported_dentry(sb, fh, parent, acceptable, context);
}
STATIC int
xfs_fs_encode_fh(
struct dentry *dentry,
__u32 *fh,
int *max_len,
int connectable)
{
struct inode *inode = dentry->d_inode;
int type = 1;
__u32 *p = fh;
int len;
int is64 = 0;
#if XFS_BIG_INUMS
bhv_vfs_t *vfs = vfs_from_sb(inode->i_sb);
if (!(vfs->vfs_flag & VFS_32BITINODES)) {
/* filesystem may contain 64bit inode numbers */
is64 = XFS_FILEID_TYPE_64FLAG;
}
#endif
/* Directories don't need their parent encoded, they have ".." */
if (S_ISDIR(inode->i_mode))
connectable = 0;
/*
* Only encode if there is enough space given. In practice
* this means we can't export a filesystem with 64bit inodes
* over NFSv2 with the subtree_check export option; the other
* seven combinations work. The real answer is "don't use v2".
*/
len = xfs_fileid_length(connectable, is64);
if (*max_len < len)
return 255;
*max_len = len;
p = xfs_fileid_encode_inode(p, inode, is64);
if (connectable) {
spin_lock(&dentry->d_lock);
p = xfs_fileid_encode_inode(p, dentry->d_parent->d_inode, is64);
spin_unlock(&dentry->d_lock);
type = 2;
}
BUG_ON((p - fh) != len);
return type | is64;
}
STATIC struct dentry *
xfs_fs_get_dentry(
struct super_block *sb,
void *data)
{
bhv_vnode_t *vp;
struct inode *inode;
struct dentry *result;
bhv_vfs_t *vfsp = vfs_from_sb(sb);
int error;
error = bhv_vfs_vget(vfsp, &vp, (fid_t *)data);
if (error || vp == NULL)
return ERR_PTR(-ESTALE) ;
inode = vn_to_inode(vp);
result = d_alloc_anon(inode);
if (!result) {
iput(inode);
return ERR_PTR(-ENOMEM);
}
return result;
}
STATIC struct dentry *
xfs_fs_get_parent(
struct dentry *child)
{
int error;
bhv_vnode_t *vp, *cvp;
struct dentry *parent;
cvp = NULL;
vp = vn_from_inode(child->d_inode);
error = bhv_vop_lookup(vp, &dotdot, &cvp, 0, NULL, NULL);
if (unlikely(error))
return ERR_PTR(-error);
parent = d_alloc_anon(vn_to_inode(cvp));
if (unlikely(!parent)) {
VN_RELE(cvp);
return ERR_PTR(-ENOMEM);
}
return parent;
}
struct export_operations xfs_export_operations = {
.decode_fh = xfs_fs_decode_fh,
.encode_fh = xfs_fs_encode_fh,
.get_parent = xfs_fs_get_parent,
.get_dentry = xfs_fs_get_dentry,
};