fef415e2068ee056255b3bda599ed638dd1bf1a0
[linux-2.6.git] / fs / gfs2 / ops_dentry.c
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 v.2.
8  */
9
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/smp_lock.h>
16 #include <linux/gfs2_ondisk.h>
17 #include <linux/crc32.h>
18
19 #include "gfs2.h"
20 #include "lm_interface.h"
21 #include "incore.h"
22 #include "dir.h"
23 #include "glock.h"
24 #include "ops_dentry.h"
25 #include "util.h"
26
27 /**
28  * gfs2_drevalidate - Check directory lookup consistency
29  * @dentry: the mapping to check
30  * @nd:
31  *
32  * Check to make sure the lookup necessary to arrive at this inode from its
33  * parent is still good.
34  *
35  * Returns: 1 if the dentry is ok, 0 if it isn't
36  */
37
38 static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
39 {
40         struct dentry *parent = dget_parent(dentry);
41         struct gfs2_sbd *sdp = parent->d_inode->i_sb->s_fs_info;
42         struct gfs2_inode *dip = parent->d_inode->u.generic_ip;
43         struct inode *inode = dentry->d_inode;
44         struct gfs2_holder d_gh;
45         struct gfs2_inode *ip;
46         struct gfs2_inum inum;
47         unsigned int type;
48         int error;
49
50         if (inode && is_bad_inode(inode))
51                 goto invalid;
52
53         if (sdp->sd_args.ar_localcaching)
54                 goto valid;
55
56         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
57         if (error)
58                 goto fail;
59
60         error = gfs2_dir_search(parent->d_inode, &dentry->d_name, &inum, &type);
61         switch (error) {
62         case 0:
63                 if (!inode)
64                         goto invalid_gunlock;
65                 break;
66         case -ENOENT:
67                 if (!inode)
68                         goto valid_gunlock;
69                 goto invalid_gunlock;
70         default:
71                 goto fail_gunlock;
72         }
73
74         ip = inode->u.generic_ip;
75
76         if (!gfs2_inum_equal(&ip->i_num, &inum))
77                 goto invalid_gunlock;
78
79         if (IF2DT(ip->i_di.di_mode) != type) {
80                 gfs2_consist_inode(dip);
81                 goto fail_gunlock;
82         }
83
84  valid_gunlock:
85         gfs2_glock_dq_uninit(&d_gh);
86
87  valid:
88         dput(parent);
89         return 1;
90
91  invalid_gunlock:
92         gfs2_glock_dq_uninit(&d_gh);
93
94  invalid:
95         if (inode && S_ISDIR(inode->i_mode)) {
96                 if (have_submounts(dentry))
97                         goto valid;
98                 shrink_dcache_parent(dentry);
99         }
100         d_drop(dentry);
101
102         dput(parent);
103         return 0;
104
105  fail_gunlock:
106         gfs2_glock_dq_uninit(&d_gh);
107
108  fail:
109         dput(parent);
110         return 0;
111 }
112
113 static 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
119 struct dentry_operations gfs2_dops = {
120         .d_revalidate = gfs2_drevalidate,
121         .d_hash = gfs2_dhash,
122 };
123