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/spinlock.h>
11#include <linux/completion.h>
12#include <linux/buffer_head.h>
13#include <linux/gfs2_ondisk.h>
14#include <linux/namei.h>
15#include <linux/crc32.h>
16
17#include "gfs2.h"
18#include "incore.h"
19#include "dir.h"
20#include "glock.h"
21#include "super.h"
22#include "util.h"
23#include "inode.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;
39	struct gfs2_sbd *sdp;
40	struct gfs2_inode *dip;
41	struct inode *inode;
42	struct gfs2_holder d_gh;
43	struct gfs2_inode *ip = NULL;
44	int error;
45	int had_lock = 0;
46
47	if (nd && nd->flags & LOOKUP_RCU)
48		return -ECHILD;
49
50	parent = dget_parent(dentry);
51	sdp = GFS2_SB(parent->d_inode);
52	dip = GFS2_I(parent->d_inode);
53	inode = dentry->d_inode;
54
55	if (inode) {
56		if (is_bad_inode(inode))
57			goto invalid;
58		ip = GFS2_I(inode);
59	}
60
61	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
62		goto valid;
63
64	had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
65	if (!had_lock) {
66		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
67		if (error)
68			goto fail;
69	}
70
71	error = gfs2_dir_check(parent->d_inode, &dentry->d_name, ip);
72	switch (error) {
73	case 0:
74		if (!inode)
75			goto invalid_gunlock;
76		break;
77	case -ENOENT:
78		if (!inode)
79			goto valid_gunlock;
80		goto invalid_gunlock;
81	default:
82		goto fail_gunlock;
83	}
84
85valid_gunlock:
86	if (!had_lock)
87		gfs2_glock_dq_uninit(&d_gh);
88valid:
89	dput(parent);
90	return 1;
91
92invalid_gunlock:
93	if (!had_lock)
94		gfs2_glock_dq_uninit(&d_gh);
95invalid:
96	if (inode && S_ISDIR(inode->i_mode)) {
97		if (have_submounts(dentry))
98			goto valid;
99		shrink_dcache_parent(dentry);
100	}
101	d_drop(dentry);
102	dput(parent);
103	return 0;
104
105fail_gunlock:
106	gfs2_glock_dq_uninit(&d_gh);
107fail:
108	dput(parent);
109	return 0;
110}
111
112static int gfs2_dhash(const struct dentry *dentry, const struct inode *inode,
113		struct qstr *str)
114{
115	str->hash = gfs2_disk_hash(str->name, str->len);
116	return 0;
117}
118
119static int gfs2_dentry_delete(const struct dentry *dentry)
120{
121	struct gfs2_inode *ginode;
122
123	if (!dentry->d_inode)
124		return 0;
125
126	ginode = GFS2_I(dentry->d_inode);
127	if (!ginode->i_iopen_gh.gh_gl)
128		return 0;
129
130	if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
131		return 1;
132
133	return 0;
134}
135
136const struct dentry_operations gfs2_dops = {
137	.d_revalidate = gfs2_drevalidate,
138	.d_hash = gfs2_dhash,
139	.d_delete = gfs2_dentry_delete,
140};
141
142