LXR linux/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#define EXT4_XATTR_INDEX_RICHACL                8
  26#define EXT4_XATTR_INDEX_ENCRYPTION             9
  27
  28struct ext4_xattr_header {
  29        __le32  h_magic;        /* magic number for identification */
  30        __le32  h_refcount;     /* reference count */
  31        __le32  h_blocks;       /* number of disk blocks used */
  32        __le32  h_hash;         /* hash value of all attributes */
  33        __le32  h_checksum;     /* crc32c(uuid+id+xattrblock) */
  34                                /* id = inum if refcount=1, blknum otherwise */
  35        __u32   h_reserved[3];  /* zero right now */
  36};
  37
  38struct ext4_xattr_ibody_header {
  39        __le32  h_magic;        /* magic number for identification */
  40};
  41
  42struct ext4_xattr_entry {
  43        __u8    e_name_len;     /* length of name */
  44        __u8    e_name_index;   /* attribute name index */
  45        __le16  e_value_offs;   /* offset in disk block of value */
  46        __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
  47        __le32  e_value_size;   /* size of attribute value */
  48        __le32  e_hash;         /* hash value of name and value */
  49        char    e_name[0];      /* attribute name */
  50};
  51
  52#define EXT4_XATTR_PAD_BITS             2
  53#define EXT4_XATTR_PAD          (1<<EXT4_XATTR_PAD_BITS)
  54#define EXT4_XATTR_ROUND                (EXT4_XATTR_PAD-1)
  55#define EXT4_XATTR_LEN(name_len) \
  56        (((name_len) + EXT4_XATTR_ROUND + \
  57        sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
  58#define EXT4_XATTR_NEXT(entry) \
  59        ((struct ext4_xattr_entry *)( \
  60         (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
  61#define EXT4_XATTR_SIZE(size) \
  62        (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
  63
  64#define IHDR(inode, raw_inode) \
  65        ((struct ext4_xattr_ibody_header *) \
  66                ((void *)raw_inode + \
  67                EXT4_GOOD_OLD_INODE_SIZE + \
  68                EXT4_I(inode)->i_extra_isize))
  69#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
  70
  71#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
  72#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
  73#define BFIRST(bh) ENTRY(BHDR(bh)+1)
  74#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
  75
  76#define EXT4_ZERO_XATTR_VALUE ((void *)-1)
  77
  78struct ext4_xattr_info {
  79        int name_index;
  80        const char *name;
  81        const void *value;
  82        size_t value_len;
  83};
  84
  85struct ext4_xattr_search {
  86        struct ext4_xattr_entry *first;
  87        void *base;
  88        void *end;
  89        struct ext4_xattr_entry *here;
  90        int not_found;
  91};
  92
  93struct ext4_xattr_ibody_find {
  94        struct ext4_xattr_search s;
  95        struct ext4_iloc iloc;
  96};
  97
  98extern const struct xattr_handler ext4_xattr_user_handler;
  99extern const struct xattr_handler ext4_xattr_trusted_handler;
 100extern const struct xattr_handler ext4_xattr_security_handler;
 101
 102#define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
 103
 104extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
 105
 106extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
 107extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
 108extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
 109
 110extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
 111extern void ext4_xattr_put_super(struct super_block *);
 112
 113extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
 114                            struct ext4_inode *raw_inode, handle_t *handle);
 115
 116extern const struct xattr_handler *ext4_xattr_handlers[];
 117
 118extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
 119                                 struct ext4_xattr_ibody_find *is);
 120extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
 121                                const char *name,
 122                                void *buffer, size_t buffer_size);
 123extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
 124                                       struct ext4_xattr_info *i,
 125                                       struct ext4_xattr_ibody_find *is);
 126
 127extern struct mb_cache *ext4_xattr_create_cache(char *name);
 128extern void ext4_xattr_destroy_cache(struct mb_cache *);
 129
 130#ifdef CONFIG_EXT4_FS_SECURITY
 131extern int ext4_init_security(handle_t *handle, struct inode *inode,
 132                              struct inode *dir, const struct qstr *qstr);
 133#else
 134static inline int ext4_init_security(handle_t *handle, struct inode *inode,
 135                                     struct inode *dir, const struct qstr *qstr)
 136{
 137        return 0;
 138}
 139#endif
 140