// SPDX-License-Identifier: GPL-2.0 /* File: fs/ext4/xattr.h On-disk format of extended attributes for the ext4 filesystem. (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org> */ #include <linux/xattr.h> /* Magic value in attribute blocks */ #define EXT4_XATTR_MAGIC 0xEA020000 /* Maximum number of references to one attribute block */ #define EXT4_XATTR_REFCOUNT_MAX 1024 /* Name indexes */ #define EXT4_XATTR_INDEX_USER 1 #define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS 2 #define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT 3 #define EXT4_XATTR_INDEX_TRUSTED 4 #define EXT4_XATTR_INDEX_LUSTRE 5 #define EXT4_XATTR_INDEX_SECURITY 6 #define EXT4_XATTR_INDEX_SYSTEM 7 #define EXT4_XATTR_INDEX_RICHACL 8 #define EXT4_XATTR_INDEX_ENCRYPTION 9 #define EXT4_XATTR_INDEX_HURD 10 /* Reserved for Hurd */ struct ext4_xattr_header { __le32 h_magic; /* magic number for identification */ __le32 h_refcount; /* reference count */ __le32 h_blocks; /* number of disk blocks used */ __le32 h_hash; /* hash value of all attributes */ __le32 h_checksum; /* crc32c(uuid+id+xattrblock) */ /* id = inum if refcount=1, blknum otherwise */ __u32 h_reserved[3]; /* zero right now */ }; struct ext4_xattr_ibody_header { __le32 h_magic; /* magic number for identification */ }; struct ext4_xattr_entry { __u8 e_name_len; /* length of name */ __u8 e_name_index; /* attribute name index */ __le16 e_value_offs; /* offset in disk block of value */ __le32 e_value_inum; /* inode in which the value is stored */ __le32 e_value_size; /* size of attribute value */ __le32 e_hash; /* hash value of name and value */ char e_name[0]; /* attribute name */ }; #define EXT4_XATTR_PAD_BITS 2 #define EXT4_XATTR_PAD (1<<EXT4_XATTR_PAD_BITS) #define EXT4_XATTR_ROUND (EXT4_XATTR_PAD-1) #define EXT4_XATTR_LEN(name_len) \ (((name_len) + EXT4_XATTR_ROUND + \ sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND) #define EXT4_XATTR_NEXT(entry) \ ((struct ext4_xattr_entry *)( \ (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len))) #define EXT4_XATTR_SIZE(size) \ (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND) #define IHDR(inode, raw_inode) \ ((struct ext4_xattr_ibody_header *) \ ((void *)raw_inode + \ EXT4_GOOD_OLD_INODE_SIZE + \ EXT4_I(inode)->i_extra_isize)) #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1)) /* * XATTR_SIZE_MAX is currently 64k, but for the purposes of checking * for file system consistency errors, we use a somewhat bigger value. * This allows XATTR_SIZE_MAX to grow in the future, but by using this * instead of INT_MAX for certain consistency checks, we don't need to * worry about arithmetic overflows. (Actually XATTR_SIZE_MAX is * defined in include/uapi/linux/limits.h, so changing it is going * not going to be trivial....) */ #define EXT4_XATTR_SIZE_MAX (1 << 24) /* * The minimum size of EA value when you start storing it in an external inode * size of block - size of header - size of 1 entry - 4 null bytes */ #define EXT4_XATTR_MIN_LARGE_EA_SIZE(b) \ ((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4) #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data)) #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr)) #define BFIRST(bh) ENTRY(BHDR(bh)+1) #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) #define EXT4_ZERO_XATTR_VALUE ((void *)-1) struct ext4_xattr_info { const char *name; const void *value; size_t value_len; int name_index; int in_inode; }; struct ext4_xattr_search { struct ext4_xattr_entry *first; void *base; void *end; struct ext4_xattr_entry *here; int not_found; }; struct ext4_xattr_ibody_find { struct ext4_xattr_search s; struct ext4_iloc iloc; }; struct ext4_xattr_inode_array { unsigned int count; /* # of used items in the array */ struct inode *inodes[0]; }; extern const struct xattr_handler ext4_xattr_user_handler; extern const struct xattr_handler ext4_xattr_trusted_handler; extern const struct xattr_handler ext4_xattr_security_handler; #define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c" /* * The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes. * The first is to signal that there the inline xattrs and data are * taking up so much space that we might as well not keep trying to * expand it. The second is that xattr_sem is taken for writing, so * we shouldn't try to recurse into the inode expansion. For this * second case, we need to make sure that we take save and restore the * NO_EXPAND state flag appropriately. */ static inline void ext4_write_lock_xattr(struct inode *inode, int *save) { down_write(&EXT4_I(inode)->xattr_sem); *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); } static inline int ext4_write_trylock_xattr(struct inode *inode, int *save) { if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0) return 0; *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); return 1; } static inline void ext4_write_unlock_xattr(struct inode *inode, int *save) { if (*save == 0) ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); up_write(&EXT4_I(inode)->xattr_sem); } extern ssize_t ext4_listxattr(struct dentry *, char *, size_t); extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t); extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int); extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int); extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len, bool is_create, int *credits); extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode, struct buffer_head *block_bh, size_t value_len, bool is_create); extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, struct ext4_xattr_inode_array **array, int extra_credits); extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array); extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, struct ext4_inode *raw_inode, handle_t *handle); extern const struct xattr_handler *ext4_xattr_handlers[]; extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, struct ext4_xattr_ibody_find *is); extern int ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, void *buffer, size_t buffer_size); extern int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode, struct ext4_xattr_info *i, struct ext4_xattr_ibody_find *is); extern struct mb_cache *ext4_xattr_create_cache(void); extern void ext4_xattr_destroy_cache(struct mb_cache *); #ifdef CONFIG_EXT4_FS_SECURITY extern int ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir, const struct qstr *qstr); #else static inline int ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir, const struct qstr *qstr) { return 0; } #endif #ifdef CONFIG_LOCKDEP extern void ext4_xattr_inode_set_class(struct inode *ea_inode); #else static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { } #endif extern int ext4_get_inode_usage(struct inode *inode, qsize_t *usage);