1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
4  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
5  */
6 
7 #include <linux/spinlock.h>
8 #include <linux/completion.h>
9 #include <linux/buffer_head.h>
10 #include <linux/gfs2_ondisk.h>
11 #include <linux/namei.h>
12 #include <linux/crc32.h>
13 
14 #include "gfs2.h"
15 #include "incore.h"
16 #include "dir.h"
17 #include "glock.h"
18 #include "super.h"
19 #include "util.h"
20 #include "inode.h"
21 
22 /**
23  * gfs2_drevalidate - Check directory lookup consistency
24  * @dir: expected parent directory inode
25  * @name: expexted name
26  * @dentry: dentry to check
27  * @flags: lookup flags
28  *
29  * Check to make sure the lookup necessary to arrive at this inode from its
30  * parent is still good.
31  *
32  * Returns: 1 if the dentry is ok, 0 if it isn't
33  */
34 
35 static int gfs2_drevalidate(struct inode *dir, const struct qstr *name,
36 			    struct dentry *dentry, unsigned int flags)
37 {
38 	struct gfs2_sbd *sdp = GFS2_SB(dir);
39 	struct gfs2_inode *dip = GFS2_I(dir);
40 	struct inode *inode;
41 	struct gfs2_holder d_gh;
42 	struct gfs2_inode *ip = NULL;
43 	int error, valid;
44 	int had_lock = 0;
45 
46 	if (flags & LOOKUP_RCU)
47 		return -ECHILD;
48 
49 	inode = d_inode(dentry);
50 
51 	if (inode) {
52 		if (is_bad_inode(inode))
53 			return 0;
54 		ip = GFS2_I(inode);
55 	}
56 
57 	if (sdp->sd_lockstruct.ls_ops->lm_mount == NULL)
58 		return 1;
59 
60 	had_lock = (gfs2_glock_is_locked_by_me(dip->i_gl) != NULL);
61 	if (!had_lock) {
62 		error = gfs2_glock_nq_init(dip->i_gl, LM_ST_SHARED, 0, &d_gh);
63 		if (error)
64 			return 0;
65 	}
66 
67 	error = gfs2_dir_check(dir, name, ip);
68 	valid = inode ? !error : (error == -ENOENT);
69 
70 	if (!had_lock)
71 		gfs2_glock_dq_uninit(&d_gh);
72 	return valid;
73 }
74 
75 static int gfs2_dhash(const struct dentry *dentry, struct qstr *str)
76 {
77 	str->hash = gfs2_disk_hash(str->name, str->len);
78 	return 0;
79 }
80 
81 static int gfs2_dentry_delete(const struct dentry *dentry)
82 {
83 	struct gfs2_inode *ginode;
84 
85 	if (d_really_is_negative(dentry))
86 		return 0;
87 
88 	ginode = GFS2_I(d_inode(dentry));
89 	if (!gfs2_holder_initialized(&ginode->i_iopen_gh))
90 		return 0;
91 
92 	if (test_bit(GLF_DEMOTE, &ginode->i_iopen_gh.gh_gl->gl_flags))
93 		return 1;
94 
95 	return 0;
96 }
97 
98 const struct dentry_operations gfs2_dops = {
99 	.d_revalidate = gfs2_drevalidate,
100 	.d_hash = gfs2_dhash,
101 	.d_delete = gfs2_dentry_delete,
102 };
103 
104