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 * The minimum size of EA value when you start storing it in an external inode 74 * size of block - size of header - size of 1 entry - 4 null bytes 75 */ 76 #define EXT4_XATTR_MIN_LARGE_EA_SIZE(b) \ 77 ((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4) 78 79 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data)) 80 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr)) 81 #define BFIRST(bh) ENTRY(BHDR(bh)+1) 82 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) 83 84 #define EXT4_ZERO_XATTR_VALUE ((void *)-1) 85 86 struct ext4_xattr_info { 87 const char *name; 88 const void *value; 89 size_t value_len; 90 int name_index; 91 int in_inode; 92 }; 93 94 struct ext4_xattr_search { 95 struct ext4_xattr_entry *first; 96 void *base; 97 void *end; 98 struct ext4_xattr_entry *here; 99 int not_found; 100 }; 101 102 struct ext4_xattr_ibody_find { 103 struct ext4_xattr_search s; 104 struct ext4_iloc iloc; 105 }; 106 107 struct ext4_xattr_inode_array { 108 unsigned int count; /* # of used items in the array */ 109 struct inode *inodes[0]; 110 }; 111 112 extern const struct xattr_handler ext4_xattr_user_handler; 113 extern const struct xattr_handler ext4_xattr_trusted_handler; 114 extern const struct xattr_handler ext4_xattr_security_handler; 115 116 #define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c" 117 118 /* 119 * The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes. 120 * The first is to signal that there the inline xattrs and data are 121 * taking up so much space that we might as well not keep trying to 122 * expand it. The second is that xattr_sem is taken for writing, so 123 * we shouldn't try to recurse into the inode expansion. For this 124 * second case, we need to make sure that we take save and restore the 125 * NO_EXPAND state flag appropriately. 126 */ 127 static inline void ext4_write_lock_xattr(struct inode *inode, int *save) 128 { 129 down_write(&EXT4_I(inode)->xattr_sem); 130 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 131 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 132 } 133 134 static inline int ext4_write_trylock_xattr(struct inode *inode, int *save) 135 { 136 if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0) 137 return 0; 138 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 139 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 140 return 1; 141 } 142 143 static inline void ext4_write_unlock_xattr(struct inode *inode, int *save) 144 { 145 if (*save == 0) 146 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 147 up_write(&EXT4_I(inode)->xattr_sem); 148 } 149 150 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t); 151 152 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t); 153 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int); 154 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int); 155 extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len, 156 bool is_create, int *credits); 157 extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode, 158 struct buffer_head *block_bh, size_t value_len, 159 bool is_create); 160 161 extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, 162 struct ext4_xattr_inode_array **array, 163 int extra_credits); 164 extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array); 165 166 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 167 struct ext4_inode *raw_inode, handle_t *handle); 168 169 extern const struct xattr_handler *ext4_xattr_handlers[]; 170 171 extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 172 struct ext4_xattr_ibody_find *is); 173 extern int ext4_xattr_ibody_get(struct inode *inode, int name_index, 174 const char *name, 175 void *buffer, size_t buffer_size); 176 extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode, 177 struct ext4_xattr_info *i, 178 struct ext4_xattr_ibody_find *is); 179 180 extern struct mb_cache *ext4_xattr_create_cache(void); 181 extern void ext4_xattr_destroy_cache(struct mb_cache *); 182 183 #ifdef CONFIG_EXT4_FS_SECURITY 184 extern int ext4_init_security(handle_t *handle, struct inode *inode, 185 struct inode *dir, const struct qstr *qstr); 186 #else 187 static inline int ext4_init_security(handle_t *handle, struct inode *inode, 188 struct inode *dir, const struct qstr *qstr) 189 { 190 return 0; 191 } 192 #endif 193 194 #ifdef CONFIG_LOCKDEP 195 extern void ext4_xattr_inode_set_class(struct inode *ea_inode); 196 #else 197 static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { } 198 #endif 199 200 extern int ext4_get_inode_usage(struct inode *inode, qsize_t *usage); 201