[GFS2] The core of GFS2
[linux-2.6] / fs / gfs2 / ops_dentry.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2005 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 <asm/semaphore.h>
17
18 #include "gfs2.h"
19 #include "dir.h"
20 #include "glock.h"
21 #include "ops_dentry.h"
22
23 /**
24  * gfs2_drevalidate - Check directory lookup consistency
25  * @dentry: the mapping to check
26  * @nd:
27  *
28  * Check to make sure the lookup necessary to arrive at this inode from its
29  * parent is still good.
30  *
31  * Returns: 1 if the dentry is ok, 0 if it isn't
32  */
33
34 static int gfs2_drevalidate(struct dentry *dentry, struct nameidata *nd)
35 {
36         struct dentry *parent = dget_parent(dentry);
37         struct gfs2_inode *dip = get_v2ip(parent->d_inode);
38         struct gfs2_sbd *sdp = dip->i_sbd;
39         struct inode *inode;
40         struct gfs2_holder d_gh;
41         struct gfs2_inode *ip;
42         struct gfs2_inum inum;
43         unsigned int type;
44         int error;
45
46         lock_kernel();
47
48         atomic_inc(&sdp->sd_ops_dentry);
49
50         inode = dentry->d_inode;
51         if (inode && is_bad_inode(inode))
52                 goto invalid;
53
54         error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
55         if (error)
56                 goto fail;
57
58         error = gfs2_dir_search(dip, &dentry->d_name, &inum, &type);
59         switch (error) {
60         case 0:
61                 if (!inode)
62                         goto invalid_gunlock;
63                 break;
64         case -ENOENT:
65                 if (!inode)
66                         goto valid_gunlock;
67                 goto invalid_gunlock;
68         default:
69                 goto fail_gunlock;
70         }
71
72         ip = get_v2ip(inode);
73
74         if (!gfs2_inum_equal(&ip->i_num, &inum))
75                 goto invalid_gunlock;
76
77         if (IF2DT(ip->i_di.di_mode) != type) {
78                 gfs2_consist_inode(dip);
79                 goto fail_gunlock;
80         }
81
82  valid_gunlock:
83         gfs2_glock_dq_uninit(&d_gh);
84
85  valid:
86         unlock_kernel();
87         dput(parent);
88         return 1;
89
90  invalid_gunlock:
91         gfs2_glock_dq_uninit(&d_gh);
92
93  invalid:
94         if (inode && S_ISDIR(inode->i_mode)) {
95                 if (have_submounts(dentry))
96                         goto valid;
97                 shrink_dcache_parent(dentry);
98         }
99         d_drop(dentry);
100
101         unlock_kernel();
102         dput(parent);
103         return 0;
104
105  fail_gunlock:
106         gfs2_glock_dq_uninit(&d_gh);
107
108  fail:
109         unlock_kernel();
110         dput(parent);
111         return 0;
112 }
113
114 struct dentry_operations gfs2_dops = {
115         .d_revalidate = gfs2_drevalidate,
116 };
117