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_inum; /* inode in which the value is stored */ 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 /* 73 * Link EA inode back to parent one using i_mtime field. 74 * Extra integer type conversion added to ignore higher 75 * bits in i_mtime.tv_sec which might be set by ext4_get() 76 */ 77 #define EXT4_XATTR_INODE_SET_PARENT(inode, inum) \ 78 do { \ 79 (inode)->i_mtime.tv_sec = inum; \ 80 } while(0) 81 82 #define EXT4_XATTR_INODE_GET_PARENT(inode) \ 83 ((__u32)(inode)->i_mtime.tv_sec) 84 85 /* 86 * The minimum size of EA value when you start storing it in an external inode 87 * size of block - size of header - size of 1 entry - 4 null bytes 88 */ 89 #define EXT4_XATTR_MIN_LARGE_EA_SIZE(b) \ 90 ((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4) 91 92 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data)) 93 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr)) 94 #define BFIRST(bh) ENTRY(BHDR(bh)+1) 95 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) 96 97 #define EXT4_ZERO_XATTR_VALUE ((void *)-1) 98 99 struct ext4_xattr_info { 100 const char *name; 101 const void *value; 102 size_t value_len; 103 int name_index; 104 int in_inode; 105 }; 106 107 struct ext4_xattr_search { 108 struct ext4_xattr_entry *first; 109 void *base; 110 void *end; 111 struct ext4_xattr_entry *here; 112 int not_found; 113 }; 114 115 struct ext4_xattr_ibody_find { 116 struct ext4_xattr_search s; 117 struct ext4_iloc iloc; 118 }; 119 120 extern const struct xattr_handler ext4_xattr_user_handler; 121 extern const struct xattr_handler ext4_xattr_trusted_handler; 122 extern const struct xattr_handler ext4_xattr_security_handler; 123 124 #define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c" 125 126 /* 127 * The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes. 128 * The first is to signal that there the inline xattrs and data are 129 * taking up so much space that we might as well not keep trying to 130 * expand it. The second is that xattr_sem is taken for writing, so 131 * we shouldn't try to recurse into the inode expansion. For this 132 * second case, we need to make sure that we take save and restore the 133 * NO_EXPAND state flag appropriately. 134 */ 135 static inline void ext4_write_lock_xattr(struct inode *inode, int *save) 136 { 137 down_write(&EXT4_I(inode)->xattr_sem); 138 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 139 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 140 } 141 142 static inline int ext4_write_trylock_xattr(struct inode *inode, int *save) 143 { 144 if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0) 145 return 0; 146 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 147 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 148 return 1; 149 } 150 151 static inline void ext4_write_unlock_xattr(struct inode *inode, int *save) 152 { 153 if (*save == 0) 154 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 155 up_write(&EXT4_I(inode)->xattr_sem); 156 } 157 158 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t); 159 160 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t); 161 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int); 162 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int); 163 164 extern struct inode *ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino, 165 int *err); 166 extern int ext4_xattr_inode_unlink(struct inode *inode, unsigned long ea_ino); 167 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, 168 struct ext4_xattr_ino_array **array); 169 extern void ext4_xattr_inode_array_free(struct inode *inode, 170 struct ext4_xattr_ino_array *array); 171 172 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 173 struct ext4_inode *raw_inode, handle_t *handle); 174 175 extern const struct xattr_handler *ext4_xattr_handlers[]; 176 177 extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 178 struct ext4_xattr_ibody_find *is); 179 extern int ext4_xattr_ibody_get(struct inode *inode, int name_index, 180 const char *name, 181 void *buffer, size_t buffer_size); 182 extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode, 183 struct ext4_xattr_info *i, 184 struct ext4_xattr_ibody_find *is); 185 186 extern struct mb_cache *ext4_xattr_create_cache(void); 187 extern void ext4_xattr_destroy_cache(struct mb_cache *); 188 189 #ifdef CONFIG_EXT4_FS_SECURITY 190 extern int ext4_init_security(handle_t *handle, struct inode *inode, 191 struct inode *dir, const struct qstr *qstr); 192 #else 193 static inline int ext4_init_security(handle_t *handle, struct inode *inode, 194 struct inode *dir, const struct qstr *qstr) 195 { 196 return 0; 197 } 198 #endif 199