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// 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[]; /* 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)
/*
* If we want to add an xattr to the inode, we should make sure that
* i_extra_isize is not 0 and that the inode size is not less than
* EXT4_GOOD_OLD_INODE_SIZE + extra_isize + pad.
* EXT4_GOOD_OLD_INODE_SIZE extra_isize header entry pad data
* |--------------------------|------------|------|---------|---|-------|
*/
#define EXT4_INODE_HAS_XATTR_SPACE(inode) \
((EXT4_I(inode)->i_extra_isize != 0) && \
(EXT4_GOOD_OLD_INODE_SIZE + EXT4_I(inode)->i_extra_isize + \
sizeof(struct ext4_xattr_ibody_header) + EXT4_XATTR_PAD <= \
EXT4_INODE_SIZE((inode)->i_sb)))
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[];
};
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;
extern const struct xattr_handler ext4_xattr_hurd_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 void ext4_evict_ea_inode(struct inode *inode);
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_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);
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