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 #define EXT4_XATTR_INDEX_HURD 10 /* Reserved for Hurd */ 28 29 struct ext4_xattr_header { 30 __le32 h_magic; /* magic number for identification */ 31 __le32 h_refcount; /* reference count */ 32 __le32 h_blocks; /* number of disk blocks used */ 33 __le32 h_hash; /* hash value of all attributes */ 34 __le32 h_checksum; /* crc32c(uuid+id+xattrblock) */ 35 /* id = inum if refcount=1, blknum otherwise */ 36 __u32 h_reserved[3]; /* zero right now */ 37 }; 38 39 struct ext4_xattr_ibody_header { 40 __le32 h_magic; /* magic number for identification */ 41 }; 42 43 struct ext4_xattr_entry { 44 __u8 e_name_len; /* length of name */ 45 __u8 e_name_index; /* attribute name index */ 46 __le16 e_value_offs; /* offset in disk block of value */ 47 __le32 e_value_block; /* disk block attribute is stored on (n/i) */ 48 __le32 e_value_size; /* size of attribute value */ 49 __le32 e_hash; /* hash value of name and value */ 50 char e_name[0]; /* attribute name */ 51 }; 52 53 #define EXT4_XATTR_PAD_BITS 2 54 #define EXT4_XATTR_PAD (1<<EXT4_XATTR_PAD_BITS) 55 #define EXT4_XATTR_ROUND (EXT4_XATTR_PAD-1) 56 #define EXT4_XATTR_LEN(name_len) \ 57 (((name_len) + EXT4_XATTR_ROUND + \ 58 sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND) 59 #define EXT4_XATTR_NEXT(entry) \ 60 ((struct ext4_xattr_entry *)( \ 61 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len))) 62 #define EXT4_XATTR_SIZE(size) \ 63 (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND) 64 65 #define IHDR(inode, raw_inode) \ 66 ((struct ext4_xattr_ibody_header *) \ 67 ((void *)raw_inode + \ 68 EXT4_GOOD_OLD_INODE_SIZE + \ 69 EXT4_I(inode)->i_extra_isize)) 70 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1)) 71 72 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data)) 73 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr)) 74 #define BFIRST(bh) ENTRY(BHDR(bh)+1) 75 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) 76 77 #define EXT4_ZERO_XATTR_VALUE ((void *)-1) 78 79 struct ext4_xattr_info { 80 int name_index; 81 const char *name; 82 const void *value; 83 size_t value_len; 84 }; 85 86 struct ext4_xattr_search { 87 struct ext4_xattr_entry *first; 88 void *base; 89 void *end; 90 struct ext4_xattr_entry *here; 91 int not_found; 92 }; 93 94 struct ext4_xattr_ibody_find { 95 struct ext4_xattr_search s; 96 struct ext4_iloc iloc; 97 }; 98 99 extern const struct xattr_handler ext4_xattr_user_handler; 100 extern const struct xattr_handler ext4_xattr_trusted_handler; 101 extern const struct xattr_handler ext4_xattr_security_handler; 102 103 #define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c" 104 105 /* 106 * The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes. 107 * The first is to signal that there the inline xattrs and data are 108 * taking up so much space that we might as well not keep trying to 109 * expand it. The second is that xattr_sem is taken for writing, so 110 * we shouldn't try to recurse into the inode expansion. For this 111 * second case, we need to make sure that we take save and restore the 112 * NO_EXPAND state flag appropriately. 113 */ 114 static inline void ext4_write_lock_xattr(struct inode *inode, int *save) 115 { 116 down_write(&EXT4_I(inode)->xattr_sem); 117 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 118 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 119 } 120 121 static inline int ext4_write_trylock_xattr(struct inode *inode, int *save) 122 { 123 if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0) 124 return 0; 125 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 126 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 127 return 1; 128 } 129 130 static inline void ext4_write_unlock_xattr(struct inode *inode, int *save) 131 { 132 if (*save == 0) 133 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 134 up_write(&EXT4_I(inode)->xattr_sem); 135 } 136 137 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t); 138 139 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t); 140 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int); 141 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int); 142 143 extern void ext4_xattr_delete_inode(handle_t *, struct inode *); 144 145 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 146 struct ext4_inode *raw_inode, handle_t *handle); 147 148 extern const struct xattr_handler *ext4_xattr_handlers[]; 149 150 extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 151 struct ext4_xattr_ibody_find *is); 152 extern int ext4_xattr_ibody_get(struct inode *inode, int name_index, 153 const char *name, 154 void *buffer, size_t buffer_size); 155 extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode, 156 struct ext4_xattr_info *i, 157 struct ext4_xattr_ibody_find *is); 158 159 extern struct mb_cache *ext4_xattr_create_cache(void); 160 extern void ext4_xattr_destroy_cache(struct mb_cache *); 161 162 #ifdef CONFIG_EXT4_FS_SECURITY 163 extern int ext4_init_security(handle_t *handle, struct inode *inode, 164 struct inode *dir, const struct qstr *qstr); 165 #else 166 static inline int ext4_init_security(handle_t *handle, struct inode *inode, 167 struct inode *dir, const struct qstr *qstr) 168 { 169 return 0; 170 } 171 #endif 172