linux/fs/ext4/xattr.h
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   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
  25struct ext4_xattr_header {
  26        __le32  h_magic;        /* magic number for identification */
  27        __le32  h_refcount;     /* reference count */
  28        __le32  h_blocks;       /* number of disk blocks used */
  29        __le32  h_hash;         /* hash value of all attributes */
  30        __le32  h_checksum;     /* crc32c(uuid+id+xattrblock) */
  31                                /* id = inum if refcount=1, blknum otherwise */
  32        __u32   h_reserved[3];  /* zero right now */
  33};
  34
  35struct ext4_xattr_ibody_header {
  36        __le32  h_magic;        /* magic number for identification */
  37};
  38
  39struct ext4_xattr_entry {
  40        __u8    e_name_len;     /* length of name */
  41        __u8    e_name_index;   /* attribute name index */
  42        __le16  e_value_offs;   /* offset in disk block of value */
  43        __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
  44        __le32  e_value_size;   /* size of attribute value */
  45        __le32  e_hash;         /* hash value of name and value */
  46        char    e_name[0];      /* attribute name */
  47};
  48
  49#define EXT4_XATTR_PAD_BITS             2
  50#define EXT4_XATTR_PAD          (1<<EXT4_XATTR_PAD_BITS)
  51#define EXT4_XATTR_ROUND                (EXT4_XATTR_PAD-1)
  52#define EXT4_XATTR_LEN(name_len) \
  53        (((name_len) + EXT4_XATTR_ROUND + \
  54        sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
  55#define EXT4_XATTR_NEXT(entry) \
  56        ((struct ext4_xattr_entry *)( \
  57         (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
  58#define EXT4_XATTR_SIZE(size) \
  59        (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
  60
  61#define IHDR(inode, raw_inode) \
  62        ((struct ext4_xattr_ibody_header *) \
  63                ((void *)raw_inode + \
  64                EXT4_GOOD_OLD_INODE_SIZE + \
  65                EXT4_I(inode)->i_extra_isize))
  66#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
  67
  68# ifdef CONFIG_EXT4_FS_XATTR
  69
  70extern const struct xattr_handler ext4_xattr_user_handler;
  71extern const struct xattr_handler ext4_xattr_trusted_handler;
  72extern const struct xattr_handler ext4_xattr_acl_access_handler;
  73extern const struct xattr_handler ext4_xattr_acl_default_handler;
  74extern const struct xattr_handler ext4_xattr_security_handler;
  75
  76extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
  77
  78extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
  79extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
  80extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
  81
  82extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
  83extern void ext4_xattr_put_super(struct super_block *);
  84
  85extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
  86                            struct ext4_inode *raw_inode, handle_t *handle);
  87
  88extern int __init ext4_init_xattr(void);
  89extern void ext4_exit_xattr(void);
  90
  91extern const struct xattr_handler *ext4_xattr_handlers[];
  92
  93# else  /* CONFIG_EXT4_FS_XATTR */
  94
  95static inline int
  96ext4_xattr_get(struct inode *inode, int name_index, const char *name,
  97               void *buffer, size_t size, int flags)
  98{
  99        return -EOPNOTSUPP;
 100}
 101
 102static inline int
 103ext4_xattr_set(struct inode *inode, int name_index, const char *name,
 104               const void *value, size_t size, int flags)
 105{
 106        return -EOPNOTSUPP;
 107}
 108
 109static inline int
 110ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 111               const char *name, const void *value, size_t size, int flags)
 112{
 113        return -EOPNOTSUPP;
 114}
 115
 116static inline void
 117ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
 118{
 119}
 120
 121static inline void
 122ext4_xattr_put_super(struct super_block *sb)
 123{
 124}
 125
 126static __init inline int
 127ext4_init_xattr(void)
 128{
 129        return 0;
 130}
 131
 132static inline void
 133ext4_exit_xattr(void)
 134{
 135}
 136
 137static inline int
 138ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
 139                            struct ext4_inode *raw_inode, handle_t *handle)
 140{
 141        return -EOPNOTSUPP;
 142}
 143
 144#define ext4_xattr_handlers     NULL
 145
 146# endif  /* CONFIG_EXT4_FS_XATTR */
 147
 148#ifdef CONFIG_EXT4_FS_SECURITY
 149extern int ext4_init_security(handle_t *handle, struct inode *inode,
 150                              struct inode *dir, const struct qstr *qstr);
 151#else
 152static inline int ext4_init_security(handle_t *handle, struct inode *inode,
 153                                     struct inode *dir, const struct qstr *qstr)
 154{
 155        return 0;
 156}
 157#endif
 158
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