xref: /linux/fs/xfs/xfs_acl.h (revision 2a2c74b2efcb1a0ca3fdcb5fbb96ad8de6a29177)
1 /*
2  * Copyright (c) 2001-2005 Silicon Graphics, Inc.
3  * All Rights Reserved.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it would be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write the Free Software Foundation,
16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17  */
18 #ifndef __XFS_ACL_H__
19 #define __XFS_ACL_H__
20 
21 struct inode;
22 struct posix_acl;
23 struct xfs_inode;
24 
25 #define XFS_ACL_NOT_PRESENT (-1)
26 
27 /* On-disk XFS access control list structure */
28 struct xfs_acl_entry {
29 	__be32	ae_tag;
30 	__be32	ae_id;
31 	__be16	ae_perm;
32 	__be16	ae_pad;		/* fill the implicit hole in the structure */
33 };
34 
35 struct xfs_acl {
36 	__be32			acl_cnt;
37 	struct xfs_acl_entry	acl_entry[0];
38 };
39 
40 /*
41  * The number of ACL entries allowed is defined by the on-disk format.
42  * For v4 superblocks, that is limited to 25 entries. For v5 superblocks, it is
43  * limited only by the maximum size of the xattr that stores the information.
44  */
45 #define XFS_ACL_MAX_ENTRIES(mp)	\
46 	(xfs_sb_version_hascrc(&mp->m_sb) \
47 		?  (XATTR_SIZE_MAX - sizeof(struct xfs_acl)) / \
48 						sizeof(struct xfs_acl_entry) \
49 		: 25)
50 
51 #define XFS_ACL_MAX_SIZE(mp) \
52 	(sizeof(struct xfs_acl) + \
53 		sizeof(struct xfs_acl_entry) * XFS_ACL_MAX_ENTRIES((mp)))
54 
55 /* On-disk XFS extended attribute names */
56 #define SGI_ACL_FILE		(unsigned char *)"SGI_ACL_FILE"
57 #define SGI_ACL_DEFAULT		(unsigned char *)"SGI_ACL_DEFAULT"
58 #define SGI_ACL_FILE_SIZE	(sizeof(SGI_ACL_FILE)-1)
59 #define SGI_ACL_DEFAULT_SIZE	(sizeof(SGI_ACL_DEFAULT)-1)
60 
61 #ifdef CONFIG_XFS_POSIX_ACL
62 extern struct posix_acl *xfs_get_acl(struct inode *inode, int type);
63 extern int xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type);
64 extern int posix_acl_access_exists(struct inode *inode);
65 extern int posix_acl_default_exists(struct inode *inode);
66 #else
67 static inline struct posix_acl *xfs_get_acl(struct inode *inode, int type)
68 {
69 	return NULL;
70 }
71 # define xfs_set_acl					NULL
72 # define posix_acl_access_exists(inode)			0
73 # define posix_acl_default_exists(inode)		0
74 #endif /* CONFIG_XFS_POSIX_ACL */
75 #endif	/* __XFS_ACL_H__ */
76