xattr.h

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/*
  File: fs/ext4/xattr.h

  On-disk format of extended attributes for the ext4 filesystem.

  (C) 2001 Andreas Gruenbacher, <[email protected]>
*/

#include <linux/xattr.h>

/* Magic value in attribute blocks */
#define EXT4_XATTR_MAGIC        0xEA020000

/* Maximum number of references to one attribute block */
#define EXT4_XATTR_REFCOUNT_MAX     1024

/* Name indexes */
#define EXT4_XATTR_INDEX_USER           1
#define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS   2
#define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT  3
#define EXT4_XATTR_INDEX_TRUSTED        4
#define EXT4_XATTR_INDEX_LUSTRE         5
#define EXT4_XATTR_INDEX_SECURITY           6

struct ext4_xattr_header {
    __le32  h_magic;    /* magic number for identification */
    __le32  h_refcount; /* reference count */
    __le32  h_blocks;   /* number of disk blocks used */
    __le32  h_hash;     /* hash value of all attributes */
    __le32  h_checksum; /* crc32c(uuid+id+xattrblock) */
                /* id = inum if refcount=1, blknum otherwise */
    __u32   h_reserved[3];  /* zero right now */
};

struct ext4_xattr_ibody_header {
    __le32  h_magic;    /* magic number for identification */
};

struct ext4_xattr_entry {
    __u8    e_name_len; /* length of name */
    __u8    e_name_index;   /* attribute name index */
    __le16  e_value_offs;   /* offset in disk block of value */
    __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
    __le32  e_value_size;   /* size of attribute value */
    __le32  e_hash;     /* hash value of name and value */
    char    e_name[0];  /* attribute name */
};

#define EXT4_XATTR_PAD_BITS     2
#define EXT4_XATTR_PAD      (1<<EXT4_XATTR_PAD_BITS)
#define EXT4_XATTR_ROUND        (EXT4_XATTR_PAD-1)
#define EXT4_XATTR_LEN(name_len) \
    (((name_len) + EXT4_XATTR_ROUND + \
    sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
#define EXT4_XATTR_NEXT(entry) \
    ((struct ext4_xattr_entry *)( \
     (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
#define EXT4_XATTR_SIZE(size) \
    (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)

#define IHDR(inode, raw_inode) \
    ((struct ext4_xattr_ibody_header *) \
        ((void *)raw_inode + \
        EXT4_GOOD_OLD_INODE_SIZE + \
        EXT4_I(inode)->i_extra_isize))
#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))

# ifdef CONFIG_EXT4_FS_XATTR

extern const struct xattr_handler ext4_xattr_user_handler;
extern const struct xattr_handler ext4_xattr_trusted_handler;
extern const struct xattr_handler ext4_xattr_acl_access_handler;
extern const struct xattr_handler ext4_xattr_acl_default_handler;
extern const struct xattr_handler ext4_xattr_security_handler;

extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);

extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);

extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
extern void ext4_xattr_put_super(struct super_block *);

extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
                struct ext4_inode *raw_inode, handle_t *handle);

extern int __init ext4_init_xattr(void);
extern void ext4_exit_xattr(void);

extern const struct xattr_handler *ext4_xattr_handlers[];

# else  /* CONFIG_EXT4_FS_XATTR */

static inline int
ext4_xattr_get(struct inode *inode, int name_index, const char *name,
           void *buffer, size_t size, int flags)
{
    return -EOPNOTSUPP;
}

static inline int
ext4_xattr_set(struct inode *inode, int name_index, const char *name,
           const void *value, size_t size, int flags)
{
    return -EOPNOTSUPP;
}

static inline int
ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
           const char *name, const void *value, size_t size, int flags)
{
    return -EOPNOTSUPP;
}

static inline void
ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
{
}

static inline void
ext4_xattr_put_super(struct super_block *sb)
{
}

static __init inline int
ext4_init_xattr(void)
{
    return 0;
}

static inline void
ext4_exit_xattr(void)
{
}

static inline int
ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
                struct ext4_inode *raw_inode, handle_t *handle)
{
    return -EOPNOTSUPP;
}

#define ext4_xattr_handlers NULL

# endif  /* CONFIG_EXT4_FS_XATTR */

#ifdef CONFIG_EXT4_FS_SECURITY
extern int ext4_init_security(handle_t *handle, struct inode *inode,
                  struct inode *dir, const struct qstr *qstr);
#else
static inline int ext4_init_security(handle_t *handle, struct inode *inode,
                     struct inode *dir, const struct qstr *qstr)
{
    return 0;
}
#endif