linux/fs/gfs2/ops_dentry.c
Steven Whitehouse feaa7bba02 [GFS2] Fix unlinked file handling
This patch fixes the way we have been dealing with unlinked,
but still open files. It removes all limits (other than memory
for inodes, as per every other filesystem) on numbers of these
which we can support on GFS2. It also means that (like other
fs) its the responsibility of the last process to close the file
to deallocate the storage, rather than the person who did the
unlinking. Note that with GFS2, those two events might take place
on different nodes.

Also there are a number of other changes:

 o We use the Linux inode subsystem as it was intended to be
used, wrt allocating GFS2 inodes
 o The Linux inode cache is now the point which we use for
local enforcement of only holding one copy of the inode in
core at once (previous to this we used the glock layer).
 o We no longer use the unlinked "special" file. We just ignore it
completely. This makes unlinking more efficient.
 o We now use the 4th block allocation state. The previously unused
state is used to track unlinked but still open inodes.
 o gfs2_inoded is no longer needed
 o Several fields are now no longer needed (and removed) from the in
core struct gfs2_inode
 o Several fields are no longer needed (and removed) from the in core
superblock

There are a number of future possible optimisations and clean ups
which have been made possible by this patch.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-06-14 15:32:57 -04:00

124 lines
2.5 KiB
C

/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/smp_lock.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include "gfs2.h"
#include "lm_interface.h"
#include "incore.h"
#include "dir.h"
#include "glock.h"
#include "ops_dentry.h"
#include "util.h"
/**
* gfs2_drevalidate - Check directory lookup consistency
* @dentry: the mapping to check
* @nd:
*
* Check to make sure the lookup necessary to arrive at this inode from its
* parent is still good.
*
* Returns: 1 if the dentry is ok, 0 if it isn't
*/
static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
{
struct dentry *parent = dget_parent(dentry);
struct gfs2_sbd *sdp = GFS2_SB(parent->d_inode);
struct gfs2_inode *dip = GFS2_I(parent->d_inode);
struct inode *inode = dentry->d_inode;
struct gfs2_holder d_gh;
struct gfs2_inode *ip;
struct gfs2_inum inum;
unsigned int type;
int error;
if (inode && is_bad_inode(inode))
goto invalid;
if (sdp->sd_args.ar_localcaching)
goto valid;
error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
if (error)
goto fail;
error = gfs2_dir_search(parent->d_inode, &dentry->d_name, &inum, &type);
switch (error) {
case 0:
if (!inode)
goto invalid_gunlock;
break;
case -ENOENT:
if (!inode)
goto valid_gunlock;
goto invalid_gunlock;
default:
goto fail_gunlock;
}
ip = GFS2_I(inode);
if (!gfs2_inum_equal(&ip->i_num, &inum))
goto invalid_gunlock;
if (IF2DT(ip->i_di.di_mode) != type) {
gfs2_consist_inode(dip);
goto fail_gunlock;
}
valid_gunlock:
gfs2_glock_dq_uninit(&d_gh);
valid:
dput(parent);
return 1;
invalid_gunlock:
gfs2_glock_dq_uninit(&d_gh);
invalid:
if (inode && S_ISDIR(inode->i_mode)) {
if (have_submounts(dentry))
goto valid;
shrink_dcache_parent(dentry);
}
d_drop(dentry);
dput(parent);
return 0;
fail_gunlock:
gfs2_glock_dq_uninit(&d_gh);
fail:
dput(parent);
return 0;
}
static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
{
str->hash = gfs2_disk_hash(str->name, str->len);
return 0;
}
struct dentry_operations gfs2_dops = {
.d_revalidate = gfs2_drevalidate,
.d_hash = gfs2_dhash,
};