1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or https://opensource.org/licenses/CDDL-1.0.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright (C) 2011 Lawrence Livermore National Security, LLC.
24  */
25 
26 #ifndef _ZFS_DCACHE_H
27 #define	_ZFS_DCACHE_H
28 
29 #include <linux/dcache.h>
30 
31 #define	dname(dentry)	((char *)((dentry)->d_name.name))
32 #define	dlen(dentry)	((int)((dentry)->d_name.len))
33 
34 #ifndef HAVE_D_MAKE_ROOT
35 #define	d_make_root(inode)	d_alloc_root(inode)
36 #endif /* HAVE_D_MAKE_ROOT */
37 
38 #ifdef HAVE_DENTRY_D_U_ALIASES
39 #define	d_alias			d_u.d_alias
40 #endif
41 
42 /*
43  * 2.6.30 API change,
44  * The const keyword was added to the 'struct dentry_operations' in
45  * the dentry structure.  To handle this we define an appropriate
46  * dentry_operations_t typedef which can be used.
47  */
48 typedef const struct dentry_operations	dentry_operations_t;
49 
50 /*
51  * 2.6.38 API addition,
52  * Added d_clear_d_op() helper function which clears some flags and the
53  * registered dentry->d_op table.  This is required because d_set_d_op()
54  * issues a warning when the dentry operations table is already set.
55  * For the .zfs control directory to work properly we must be able to
56  * override the default operations table and register custom .d_automount
57  * and .d_revalidate callbacks.
58  */
59 static inline void
60 d_clear_d_op(struct dentry *dentry)
61 {
62 	dentry->d_op = NULL;
63 	dentry->d_flags &= ~(
64 	    DCACHE_OP_HASH | DCACHE_OP_COMPARE |
65 	    DCACHE_OP_REVALIDATE | DCACHE_OP_DELETE);
66 }
67 
68 /*
69  * Walk and invalidate all dentry aliases of an inode
70  * unless it's a mountpoint
71  */
72 static inline void
73 zpl_d_drop_aliases(struct inode *inode)
74 {
75 	struct dentry *dentry;
76 	spin_lock(&inode->i_lock);
77 	hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) {
78 		if (!IS_ROOT(dentry) && !d_mountpoint(dentry) &&
79 		    (dentry->d_inode == inode)) {
80 			d_drop(dentry);
81 		}
82 	}
83 	spin_unlock(&inode->i_lock);
84 }
85 #endif /* _ZFS_DCACHE_H */
86