fs/ext2/xattr.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002 /*
0003   File: linux/ext2_xattr.h
0004
0005   On-disk format of extended attributes for the ext2 filesystem.
0006
0007   (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
0008 */
0009
0010 #include <linux/init.h>
0011 #include <linux/xattr.h>
0012
0013 /* Magic value in attribute blocks */
0014 #define EXT2_XATTR_MAGIC        0xEA020000
0015
0016 /* Maximum number of references to one attribute block */
0017 #define EXT2_XATTR_REFCOUNT_MAX     1024
0018
0019 /* Name indexes */
0020 #define EXT2_XATTR_INDEX_USER           1
0021 #define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS   2
0022 #define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT  3
0023 #define EXT2_XATTR_INDEX_TRUSTED        4
0024 #define EXT2_XATTR_INDEX_LUSTRE         5
0025 #define EXT2_XATTR_INDEX_SECURITY           6
0026
0027 struct ext2_xattr_header {
0028     __le32  h_magic;    /* magic number for identification */
0029     __le32  h_refcount; /* reference count */
0030     __le32  h_blocks;   /* number of disk blocks used */
0031     __le32  h_hash;     /* hash value of all attributes */
0032     __u32   h_reserved[4];  /* zero right now */
0033 };
0034
0035 struct ext2_xattr_entry {
0036     __u8    e_name_len; /* length of name */
0037     __u8    e_name_index;   /* attribute name index */
0038     __le16  e_value_offs;   /* offset in disk block of value */
0039     __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
0040     __le32  e_value_size;   /* size of attribute value */
0041     __le32  e_hash;     /* hash value of name and value */
0042     char    e_name[];   /* attribute name */
0043 };
0044
0045 #define EXT2_XATTR_PAD_BITS     2
0046 #define EXT2_XATTR_PAD      (1<<EXT2_XATTR_PAD_BITS)
0047 #define EXT2_XATTR_ROUND        (EXT2_XATTR_PAD-1)
0048 #define EXT2_XATTR_LEN(name_len) \
0049     (((name_len) + EXT2_XATTR_ROUND + \
0050     sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
0051 #define EXT2_XATTR_NEXT(entry) \
0052     ( (struct ext2_xattr_entry *)( \
0053       (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
0054 #define EXT2_XATTR_SIZE(size) \
0055     (((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
0056
0057 struct mb_cache;
0058
0059 # ifdef CONFIG_EXT2_FS_XATTR
0060
0061 extern const struct xattr_handler ext2_xattr_user_handler;
0062 extern const struct xattr_handler ext2_xattr_trusted_handler;
0063 extern const struct xattr_handler ext2_xattr_security_handler;
0064
0065 extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
0066
0067 extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
0068 extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
0069
0070 extern void ext2_xattr_delete_inode(struct inode *);
0071
0072 extern struct mb_cache *ext2_xattr_create_cache(void);
0073 extern void ext2_xattr_destroy_cache(struct mb_cache *cache);
0074
0075 extern const struct xattr_handler *ext2_xattr_handlers[];
0076
0077 # else  /* CONFIG_EXT2_FS_XATTR */
0078
0079 static inline int
0080 ext2_xattr_get(struct inode *inode, int name_index,
0081            const char *name, void *buffer, size_t size)
0082 {
0083     return -EOPNOTSUPP;
0084 }
0085
0086 static inline int
0087 ext2_xattr_set(struct inode *inode, int name_index, const char *name,
0088            const void *value, size_t size, int flags)
0089 {
0090     return -EOPNOTSUPP;
0091 }
0092
0093 static inline void
0094 ext2_xattr_delete_inode(struct inode *inode)
0095 {
0096 }
0097
0098 static inline void ext2_xattr_destroy_cache(struct mb_cache *cache)
0099 {
0100 }
0101
0102 #define ext2_xattr_handlers NULL
0103 #define ext2_listxattr NULL
0104
0105 # endif  /* CONFIG_EXT2_FS_XATTR */
0106
0107 #ifdef CONFIG_EXT2_FS_SECURITY
0108 extern int ext2_init_security(struct inode *inode, struct inode *dir,
0109                   const struct qstr *qstr);
0110 #else
0111 static inline int ext2_init_security(struct inode *inode, struct inode *dir,
0112                      const struct qstr *qstr)
0113 {
0114     return 0;
0115 }
0116 #endif