1/*
2 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4 *
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
8 */
9
10#include <linux/slab.h>
11#include <linux/spinlock.h>
12#include <linux/completion.h>
13#include <linux/buffer_head.h>
14#include <linux/gfs2_ondisk.h>
15#include <linux/crc32.h>
16#include <linux/lm_interface.h>
17
18#include "gfs2.h"
19#include "incore.h"
20#include "dir.h"
21#include "glock.h"
22#include "ops_dentry.h"
23#include "util.h"
24
25/**
26 * gfs2_drevalidate - Check directory lookup consistency
27 * @dentry: the mapping to check
28 * @nd:
29 *
30 * Check to make sure the lookup necessary to arrive at this inode from its
31 * parent is still good.
32 *
33 * Returns: 1 if the dentry is ok, 0 if it isn't
34 */
35
36static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
37{
38	struct dentry *parent = dget_parent(dentry);
39	struct gfs2_sbd *sdp = GFS2_SB(parent->d_inode);
40	struct gfs2_inode *dip = GFS2_I(parent->d_inode);
41	struct inode *inode = dentry->d_inode;
42	struct gfs2_holder d_gh;
43	struct gfs2_inode *ip;
44	struct gfs2_inum_host inum;
45	unsigned int type;
46	int error;
47	int had_lock=0;
48
49	if (inode && is_bad_inode(inode))
50		goto invalid;
51
52	if (sdp->sd_args.ar_localcaching)
53		goto valid;
54
55	had_lock = gfs2_glock_is_locked_by_me(dip->i_gl);
56	if (!had_lock) {
57		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
58		if (error)
59			goto fail;
60	}
61
62	error = gfs2_dir_search(parent->d_inode, &dentry->d_name, &inum, &type);
63	switch (error) {
64	case 0:
65		if (!inode)
66			goto invalid_gunlock;
67		break;
68	case -ENOENT:
69		if (!inode)
70			goto valid_gunlock;
71		goto invalid_gunlock;
72	default:
73		goto fail_gunlock;
74	}
75
76	ip = GFS2_I(inode);
77
78	if (!gfs2_inum_equal(&ip->i_num, &inum))
79		goto invalid_gunlock;
80
81	if (IF2DT(ip->i_inode.i_mode) != type) {
82		gfs2_consist_inode(dip);
83		goto fail_gunlock;
84	}
85
86valid_gunlock:
87	if (!had_lock)
88		gfs2_glock_dq_uninit(&d_gh);
89valid:
90	dput(parent);
91	return 1;
92
93invalid_gunlock:
94	if (!had_lock)
95		gfs2_glock_dq_uninit(&d_gh);
96invalid:
97	if (inode && S_ISDIR(inode->i_mode)) {
98		if (have_submounts(dentry))
99			goto valid;
100		shrink_dcache_parent(dentry);
101	}
102	d_drop(dentry);
103	dput(parent);
104	return 0;
105
106fail_gunlock:
107	gfs2_glock_dq_uninit(&d_gh);
108fail:
109	dput(parent);
110	return 0;
111}
112
113static int gfs2_dhash(struct dentry *dentry, struct qstr *str)
114{
115	str->hash = gfs2_disk_hash(str->name, str->len);
116	return 0;
117}
118
119struct dentry_operations gfs2_dops = {
120	.d_revalidate = gfs2_drevalidate,
121	.d_hash = gfs2_dhash,
122};
123