fs/ext4/xattr.h

   1 /*
   2   File: fs/ext4/xattr.h
   3
   4   On-disk format of extended attributes for the ext4 filesystem.
   5
   6   (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
   7 */
   8
   9 #include <linux/xattr.h>
  10
  11 /* Magic value in attribute blocks */
  12 #define EXT4_XATTR_MAGIC                0xEA020000
  13
  14 /* Maximum number of references to one attribute block */
  15 #define EXT4_XATTR_REFCOUNT_MAX         1024
  16
  17 /* Name indexes */
  18 #define EXT4_XATTR_INDEX_USER                   1
  19 #define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS       2
  20 #define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT      3
  21 #define EXT4_XATTR_INDEX_TRUSTED                4
  22 #define EXT4_XATTR_INDEX_LUSTRE                 5
  23 #define EXT4_XATTR_INDEX_SECURITY               6
  24 #define EXT4_XATTR_INDEX_SYSTEM                 7
  25
  26 struct ext4_xattr_header {
  27         __le32  h_magic;        /* magic number for identification */
  28         __le32  h_refcount;     /* reference count */
  29         __le32  h_blocks;       /* number of disk blocks used */
  30         __le32  h_hash;         /* hash value of all attributes */
  31         __le32  h_checksum;     /* crc32c(uuid+id+xattrblock) */
  32                                 /* id = inum if refcount=1, blknum otherwise */
  33         __u32   h_reserved[3];  /* zero right now */
  34 };
  35
  36 struct ext4_xattr_ibody_header {
  37         __le32  h_magic;        /* magic number for identification */
  38 };
  39
  40 struct ext4_xattr_entry {
  41         __u8    e_name_len;     /* length of name */
  42         __u8    e_name_index;   /* attribute name index */
  43         __le16  e_value_offs;   /* offset in disk block of value */
  44         __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
  45         __le32  e_value_size;   /* size of attribute value */
  46         __le32  e_hash;         /* hash value of name and value */
  47         char    e_name[0];      /* attribute name */
  48 };
  49
  50 #define EXT4_XATTR_PAD_BITS             2
  51 #define EXT4_XATTR_PAD          (1<<EXT4_XATTR_PAD_BITS)
  52 #define EXT4_XATTR_ROUND                (EXT4_XATTR_PAD-1)
  53 #define EXT4_XATTR_LEN(name_len) \
  54         (((name_len) + EXT4_XATTR_ROUND + \
  55         sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
  56 #define EXT4_XATTR_NEXT(entry) \
  57         ((struct ext4_xattr_entry *)( \
  58          (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
  59 #define EXT4_XATTR_SIZE(size) \
  60         (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
  61
  62 #define IHDR(inode, raw_inode) \
  63         ((struct ext4_xattr_ibody_header *) \
  64                 ((void *)raw_inode + \
  65                 EXT4_GOOD_OLD_INODE_SIZE + \
  66                 EXT4_I(inode)->i_extra_isize))
  67 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
  68
  69 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
  70 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
  71 #define BFIRST(bh) ENTRY(BHDR(bh)+1)
  72 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
  73
  74 #define EXT4_ZERO_XATTR_VALUE ((void *)-1)
  75
  76 struct ext4_xattr_info {
  77         int name_index;
  78         const char *name;
  79         const void *value;
  80         size_t value_len;
  81 };
  82
  83 struct ext4_xattr_search {
  84         struct ext4_xattr_entry *first;
  85         void *base;
  86         void *end;
  87         struct ext4_xattr_entry *here;
  88         int not_found;
  89 };
  90
  91 struct ext4_xattr_ibody_find {
  92         struct ext4_xattr_search s;
  93         struct ext4_iloc iloc;
  94 };
  95
  96 extern const struct xattr_handler ext4_xattr_user_handler;
  97 extern const struct xattr_handler ext4_xattr_trusted_handler;
  98 extern const struct xattr_handler ext4_xattr_acl_access_handler;
  99 extern const struct xattr_handler ext4_xattr_acl_default_handler;
 100 extern const struct xattr_handler ext4_xattr_security_handler;
 101
 102 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 103
 104 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 105 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 106 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
 107
 108 extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
 109 extern void ext4_xattr_put_super(struct super_block *);
 110
 111 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
 112                             struct ext4_inode *raw_inode, handle_t *handle);
 113
 114 extern int __init ext4_init_xattr(void);
 115 extern void ext4_exit_xattr(void);
 116
 117 extern const struct xattr_handler *ext4_xattr_handlers[];
 118
 119 extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 120                                  struct ext4_xattr_ibody_find *is);
 121 extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
 122                                 const char *name,
 123                                 void *buffer, size_t buffer_size);
 124 extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
 125                                        struct ext4_xattr_info *i,
 126                                        struct ext4_xattr_ibody_find *is);
 127
 128 #ifdef CONFIG_EXT4_FS_SECURITY
 129 extern int ext4_init_security(handle_t *handle, struct inode *inode,
 130                               struct inode *dir, const struct qstr *qstr);
 131 #else
 132 static inline int ext4_init_security(handle_t *handle, struct inode *inode,
 133                                      struct inode *dir, const struct qstr *qstr)
 134 {
 135         return 0;
 136 }
 137 #endif