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1// SPDX-License-Identifier: GPL-2.02/*3 File: fs/ext4/xattr.h4 5 On-disk format of extended attributes for the ext4 filesystem.6 7 (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>8*/9 10#include <linux/xattr.h>11 12/* Magic value in attribute blocks */13#define EXT4_XATTR_MAGIC 0xEA02000014 15/* Maximum number of references to one attribute block */16#define EXT4_XATTR_REFCOUNT_MAX 102417 18/* Name indexes */19#define EXT4_XATTR_INDEX_USER 120#define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS 221#define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT 322#define EXT4_XATTR_INDEX_TRUSTED 423#define EXT4_XATTR_INDEX_LUSTRE 524#define EXT4_XATTR_INDEX_SECURITY 625#define EXT4_XATTR_INDEX_SYSTEM 726#define EXT4_XATTR_INDEX_RICHACL 827#define EXT4_XATTR_INDEX_ENCRYPTION 928#define EXT4_XATTR_INDEX_HURD 10 /* Reserved for Hurd */29 30struct ext4_xattr_header {31 __le32 h_magic; /* magic number for identification */32 __le32 h_refcount; /* reference count */33 __le32 h_blocks; /* number of disk blocks used */34 __le32 h_hash; /* hash value of all attributes */35 __le32 h_checksum; /* crc32c(uuid+blknum+xattrblock) */36 __u32 h_reserved[3]; /* zero right now */37};38 39struct ext4_xattr_ibody_header {40 __le32 h_magic; /* magic number for identification */41};42 43struct 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[]; /* attribute name */51};52 53#define EXT4_XATTR_PAD_BITS 254#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 * XATTR_SIZE_MAX is currently 64k, but for the purposes of checking74 * for file system consistency errors, we use a somewhat bigger value.75 * This allows XATTR_SIZE_MAX to grow in the future, but by using this76 * instead of INT_MAX for certain consistency checks, we don't need to77 * worry about arithmetic overflows. (Actually XATTR_SIZE_MAX is78 * defined in include/uapi/linux/limits.h, so changing it is going79 * not going to be trivial....)80 */81#define EXT4_XATTR_SIZE_MAX (1 << 24)82 83/*84 * The minimum size of EA value when you start storing it in an external inode85 * size of block - size of header - size of 1 entry - 4 null bytes86 */87#define EXT4_XATTR_MIN_LARGE_EA_SIZE(b) \88 ((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4)89 90#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))91#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))92#define BFIRST(bh) ENTRY(BHDR(bh)+1)93#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)94 95#define EXT4_ZERO_XATTR_VALUE ((void *)-1)96 97/*98 * If we want to add an xattr to the inode, we should make sure that99 * i_extra_isize is not 0 and that the inode size is not less than100 * EXT4_GOOD_OLD_INODE_SIZE + extra_isize + pad.101 * EXT4_GOOD_OLD_INODE_SIZE extra_isize header entry pad data102 * |--------------------------|------------|------|---------|---|-------|103 */104#define EXT4_INODE_HAS_XATTR_SPACE(inode) \105 ((EXT4_I(inode)->i_extra_isize != 0) && \106 (EXT4_GOOD_OLD_INODE_SIZE + EXT4_I(inode)->i_extra_isize + \107 sizeof(struct ext4_xattr_ibody_header) + EXT4_XATTR_PAD <= \108 EXT4_INODE_SIZE((inode)->i_sb)))109 110struct ext4_xattr_info {111 const char *name;112 const void *value;113 size_t value_len;114 int name_index;115 int in_inode;116};117 118struct ext4_xattr_search {119 struct ext4_xattr_entry *first;120 void *base;121 void *end;122 struct ext4_xattr_entry *here;123 int not_found;124};125 126struct ext4_xattr_ibody_find {127 struct ext4_xattr_search s;128 struct ext4_iloc iloc;129};130 131struct ext4_xattr_inode_array {132 unsigned int count;133 struct inode *inodes[] __counted_by(count);134};135 136extern const struct xattr_handler ext4_xattr_user_handler;137extern const struct xattr_handler ext4_xattr_trusted_handler;138extern const struct xattr_handler ext4_xattr_security_handler;139extern const struct xattr_handler ext4_xattr_hurd_handler;140 141#define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"142 143/*144 * The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes.145 * The first is to signal that there the inline xattrs and data are146 * taking up so much space that we might as well not keep trying to147 * expand it. The second is that xattr_sem is taken for writing, so148 * we shouldn't try to recurse into the inode expansion. For this149 * second case, we need to make sure that we take save and restore the150 * NO_EXPAND state flag appropriately.151 */152static inline void ext4_write_lock_xattr(struct inode *inode, int *save)153{154 down_write(&EXT4_I(inode)->xattr_sem);155 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);156 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);157}158 159static inline int ext4_write_trylock_xattr(struct inode *inode, int *save)160{161 if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0)162 return 0;163 *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);164 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);165 return 1;166}167 168static inline void ext4_write_unlock_xattr(struct inode *inode, int *save)169{170 if (*save == 0)171 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);172 up_write(&EXT4_I(inode)->xattr_sem);173}174 175extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);176 177extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);178extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);179extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);180extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,181 bool is_create, int *credits);182extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,183 struct buffer_head *block_bh, size_t value_len,184 bool is_create);185 186extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,187 struct ext4_xattr_inode_array **array,188 int extra_credits);189extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);190 191extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,192 struct ext4_inode *raw_inode, handle_t *handle);193extern void ext4_evict_ea_inode(struct inode *inode);194 195extern const struct xattr_handler * const ext4_xattr_handlers[];196 197extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,198 struct ext4_xattr_ibody_find *is);199extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,200 const char *name,201 void *buffer, size_t buffer_size);202extern int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,203 struct ext4_xattr_info *i,204 struct ext4_xattr_ibody_find *is);205 206extern struct mb_cache *ext4_xattr_create_cache(void);207extern void ext4_xattr_destroy_cache(struct mb_cache *);208 209#ifdef CONFIG_EXT4_FS_SECURITY210extern int ext4_init_security(handle_t *handle, struct inode *inode,211 struct inode *dir, const struct qstr *qstr);212#else213static inline int ext4_init_security(handle_t *handle, struct inode *inode,214 struct inode *dir, const struct qstr *qstr)215{216 return 0;217}218#endif219 220#ifdef CONFIG_LOCKDEP221extern void ext4_xattr_inode_set_class(struct inode *ea_inode);222#else223static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { }224#endif225 226extern int ext4_get_inode_usage(struct inode *inode, qsize_t *usage);227