1f5166768STheodore Ts'o // SPDX-License-Identifier: GPL-2.0
2ac27a0ecSDave Kleikamp /*
3617ba13bSMingming Cao File: fs/ext4/xattr.h
4ac27a0ecSDave Kleikamp
5617ba13bSMingming Cao On-disk format of extended attributes for the ext4 filesystem.
6ac27a0ecSDave Kleikamp
7ac27a0ecSDave Kleikamp (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
8ac27a0ecSDave Kleikamp */
9ac27a0ecSDave Kleikamp
10ac27a0ecSDave Kleikamp #include <linux/xattr.h>
11ac27a0ecSDave Kleikamp
12ac27a0ecSDave Kleikamp /* Magic value in attribute blocks */
13617ba13bSMingming Cao #define EXT4_XATTR_MAGIC 0xEA020000
14ac27a0ecSDave Kleikamp
15ac27a0ecSDave Kleikamp /* Maximum number of references to one attribute block */
16617ba13bSMingming Cao #define EXT4_XATTR_REFCOUNT_MAX 1024
17ac27a0ecSDave Kleikamp
18ac27a0ecSDave Kleikamp /* Name indexes */
19617ba13bSMingming Cao #define EXT4_XATTR_INDEX_USER 1
20617ba13bSMingming Cao #define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS 2
21617ba13bSMingming Cao #define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT 3
22617ba13bSMingming Cao #define EXT4_XATTR_INDEX_TRUSTED 4
23617ba13bSMingming Cao #define EXT4_XATTR_INDEX_LUSTRE 5
24617ba13bSMingming Cao #define EXT4_XATTR_INDEX_SECURITY 6
2567cf5b09STao Ma #define EXT4_XATTR_INDEX_SYSTEM 7
26fd03d8daSTheodore Ts'o #define EXT4_XATTR_INDEX_RICHACL 8
27887e2c45SMichael Halcrow #define EXT4_XATTR_INDEX_ENCRYPTION 9
283980bd3bSTheodore Ts'o #define EXT4_XATTR_INDEX_HURD 10 /* Reserved for Hurd */
29ac27a0ecSDave Kleikamp
30617ba13bSMingming Cao struct ext4_xattr_header {
31ac27a0ecSDave Kleikamp __le32 h_magic; /* magic number for identification */
32ac27a0ecSDave Kleikamp __le32 h_refcount; /* reference count */
33ac27a0ecSDave Kleikamp __le32 h_blocks; /* number of disk blocks used */
34ac27a0ecSDave Kleikamp __le32 h_hash; /* hash value of all attributes */
35e6153918SDarrick J. Wong __le32 h_checksum; /* crc32c(uuid+id+xattrblock) */
36e6153918SDarrick J. Wong /* id = inum if refcount=1, blknum otherwise */
37e6153918SDarrick J. Wong __u32 h_reserved[3]; /* zero right now */
38ac27a0ecSDave Kleikamp };
39ac27a0ecSDave Kleikamp
40617ba13bSMingming Cao struct ext4_xattr_ibody_header {
41ac27a0ecSDave Kleikamp __le32 h_magic; /* magic number for identification */
42ac27a0ecSDave Kleikamp };
43ac27a0ecSDave Kleikamp
44617ba13bSMingming Cao struct ext4_xattr_entry {
45ac27a0ecSDave Kleikamp __u8 e_name_len; /* length of name */
46ac27a0ecSDave Kleikamp __u8 e_name_index; /* attribute name index */
47ac27a0ecSDave Kleikamp __le16 e_value_offs; /* offset in disk block of value */
48e50e5129SAndreas Dilger __le32 e_value_inum; /* inode in which the value is stored */
49ac27a0ecSDave Kleikamp __le32 e_value_size; /* size of attribute value */
50ac27a0ecSDave Kleikamp __le32 e_hash; /* hash value of name and value */
5147b10306SGustavo A. R. Silva char e_name[]; /* attribute name */
52ac27a0ecSDave Kleikamp };
53ac27a0ecSDave Kleikamp
54617ba13bSMingming Cao #define EXT4_XATTR_PAD_BITS 2
55617ba13bSMingming Cao #define EXT4_XATTR_PAD (1<<EXT4_XATTR_PAD_BITS)
56617ba13bSMingming Cao #define EXT4_XATTR_ROUND (EXT4_XATTR_PAD-1)
57617ba13bSMingming Cao #define EXT4_XATTR_LEN(name_len) \
58617ba13bSMingming Cao (((name_len) + EXT4_XATTR_ROUND + \
59617ba13bSMingming Cao sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
60617ba13bSMingming Cao #define EXT4_XATTR_NEXT(entry) \
61617ba13bSMingming Cao ((struct ext4_xattr_entry *)( \
62617ba13bSMingming Cao (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
63617ba13bSMingming Cao #define EXT4_XATTR_SIZE(size) \
64617ba13bSMingming Cao (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
65ac27a0ecSDave Kleikamp
666dd4ee7cSKalpak Shah #define IHDR(inode, raw_inode) \
676dd4ee7cSKalpak Shah ((struct ext4_xattr_ibody_header *) \
686dd4ee7cSKalpak Shah ((void *)raw_inode + \
696dd4ee7cSKalpak Shah EXT4_GOOD_OLD_INODE_SIZE + \
706dd4ee7cSKalpak Shah EXT4_I(inode)->i_extra_isize))
716dd4ee7cSKalpak Shah #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
726dd4ee7cSKalpak Shah
73e50e5129SAndreas Dilger /*
7454dd0e0aSTheodore Ts'o * XATTR_SIZE_MAX is currently 64k, but for the purposes of checking
7554dd0e0aSTheodore Ts'o * for file system consistency errors, we use a somewhat bigger value.
7654dd0e0aSTheodore Ts'o * This allows XATTR_SIZE_MAX to grow in the future, but by using this
7754dd0e0aSTheodore Ts'o * instead of INT_MAX for certain consistency checks, we don't need to
7854dd0e0aSTheodore Ts'o * worry about arithmetic overflows. (Actually XATTR_SIZE_MAX is
7954dd0e0aSTheodore Ts'o * defined in include/uapi/linux/limits.h, so changing it is going
8054dd0e0aSTheodore Ts'o * not going to be trivial....)
8154dd0e0aSTheodore Ts'o */
8254dd0e0aSTheodore Ts'o #define EXT4_XATTR_SIZE_MAX (1 << 24)
8354dd0e0aSTheodore Ts'o
8454dd0e0aSTheodore Ts'o /*
85e50e5129SAndreas Dilger * The minimum size of EA value when you start storing it in an external inode
86e50e5129SAndreas Dilger * size of block - size of header - size of 1 entry - 4 null bytes
87e50e5129SAndreas Dilger */
88e50e5129SAndreas Dilger #define EXT4_XATTR_MIN_LARGE_EA_SIZE(b) \
89e50e5129SAndreas Dilger ((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4)
90e50e5129SAndreas Dilger
91879b3825STao Ma #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
92879b3825STao Ma #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
93879b3825STao Ma #define BFIRST(bh) ENTRY(BHDR(bh)+1)
94879b3825STao Ma #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
95879b3825STao Ma
96bd9926e8STheodore Ts'o #define EXT4_ZERO_XATTR_VALUE ((void *)-1)
97879b3825STao Ma
98179b1415SBaokun Li /*
99179b1415SBaokun Li * If we want to add an xattr to the inode, we should make sure that
100179b1415SBaokun Li * i_extra_isize is not 0 and that the inode size is not less than
101179b1415SBaokun Li * EXT4_GOOD_OLD_INODE_SIZE + extra_isize + pad.
102179b1415SBaokun Li * EXT4_GOOD_OLD_INODE_SIZE extra_isize header entry pad data
103179b1415SBaokun Li * |--------------------------|------------|------|---------|---|-------|
104179b1415SBaokun Li */
105179b1415SBaokun Li #define EXT4_INODE_HAS_XATTR_SPACE(inode) \
106179b1415SBaokun Li ((EXT4_I(inode)->i_extra_isize != 0) && \
107179b1415SBaokun Li (EXT4_GOOD_OLD_INODE_SIZE + EXT4_I(inode)->i_extra_isize + \
108179b1415SBaokun Li sizeof(struct ext4_xattr_ibody_header) + EXT4_XATTR_PAD <= \
109179b1415SBaokun Li EXT4_INODE_SIZE((inode)->i_sb)))
110179b1415SBaokun Li
111879b3825STao Ma struct ext4_xattr_info {
112879b3825STao Ma const char *name;
113879b3825STao Ma const void *value;
114879b3825STao Ma size_t value_len;
115e50e5129SAndreas Dilger int name_index;
116e50e5129SAndreas Dilger int in_inode;
117879b3825STao Ma };
118879b3825STao Ma
119879b3825STao Ma struct ext4_xattr_search {
120879b3825STao Ma struct ext4_xattr_entry *first;
121879b3825STao Ma void *base;
122879b3825STao Ma void *end;
123879b3825STao Ma struct ext4_xattr_entry *here;
124879b3825STao Ma int not_found;
125879b3825STao Ma };
126879b3825STao Ma
127879b3825STao Ma struct ext4_xattr_ibody_find {
128879b3825STao Ma struct ext4_xattr_search s;
129879b3825STao Ma struct ext4_iloc iloc;
130879b3825STao Ma };
131879b3825STao Ma
132b6d9029dSTahsin Erdogan struct ext4_xattr_inode_array {
133b6d9029dSTahsin Erdogan unsigned int count; /* # of used items in the array */
13447b10306SGustavo A. R. Silva struct inode *inodes[];
135b6d9029dSTahsin Erdogan };
136b6d9029dSTahsin Erdogan
13711e27528SStephen Hemminger extern const struct xattr_handler ext4_xattr_user_handler;
13811e27528SStephen Hemminger extern const struct xattr_handler ext4_xattr_trusted_handler;
13911e27528SStephen Hemminger extern const struct xattr_handler ext4_xattr_security_handler;
14088ee9d57SJan (janneke) Nieuwenhuizen extern const struct xattr_handler ext4_xattr_hurd_handler;
141ac27a0ecSDave Kleikamp
142887e2c45SMichael Halcrow #define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
143887e2c45SMichael Halcrow
144c755e251STheodore Ts'o /*
145c755e251STheodore Ts'o * The EXT4_STATE_NO_EXPAND is overloaded and used for two purposes.
146c755e251STheodore Ts'o * The first is to signal that there the inline xattrs and data are
147c755e251STheodore Ts'o * taking up so much space that we might as well not keep trying to
148c755e251STheodore Ts'o * expand it. The second is that xattr_sem is taken for writing, so
149c755e251STheodore Ts'o * we shouldn't try to recurse into the inode expansion. For this
150c755e251STheodore Ts'o * second case, we need to make sure that we take save and restore the
151c755e251STheodore Ts'o * NO_EXPAND state flag appropriately.
152c755e251STheodore Ts'o */
ext4_write_lock_xattr(struct inode * inode,int * save)153c755e251STheodore Ts'o static inline void ext4_write_lock_xattr(struct inode *inode, int *save)
154c755e251STheodore Ts'o {
155c755e251STheodore Ts'o down_write(&EXT4_I(inode)->xattr_sem);
156c755e251STheodore Ts'o *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
157c755e251STheodore Ts'o ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
158c755e251STheodore Ts'o }
159c755e251STheodore Ts'o
ext4_write_trylock_xattr(struct inode * inode,int * save)160c755e251STheodore Ts'o static inline int ext4_write_trylock_xattr(struct inode *inode, int *save)
161c755e251STheodore Ts'o {
162c755e251STheodore Ts'o if (down_write_trylock(&EXT4_I(inode)->xattr_sem) == 0)
163c755e251STheodore Ts'o return 0;
164c755e251STheodore Ts'o *save = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
165c755e251STheodore Ts'o ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
166c755e251STheodore Ts'o return 1;
167c755e251STheodore Ts'o }
168c755e251STheodore Ts'o
ext4_write_unlock_xattr(struct inode * inode,int * save)169c755e251STheodore Ts'o static inline void ext4_write_unlock_xattr(struct inode *inode, int *save)
170c755e251STheodore Ts'o {
171c755e251STheodore Ts'o if (*save == 0)
172c755e251STheodore Ts'o ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
173c755e251STheodore Ts'o up_write(&EXT4_I(inode)->xattr_sem);
174c755e251STheodore Ts'o }
175c755e251STheodore Ts'o
176617ba13bSMingming Cao extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
177ac27a0ecSDave Kleikamp
178617ba13bSMingming Cao extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
179617ba13bSMingming Cao extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
180617ba13bSMingming Cao extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
181dec214d0STahsin Erdogan extern int ext4_xattr_set_credits(struct inode *inode, size_t value_len,
182af65207cSTahsin Erdogan bool is_create, int *credits);
183af65207cSTahsin Erdogan extern int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode,
184af65207cSTahsin Erdogan struct buffer_head *block_bh, size_t value_len,
185af65207cSTahsin Erdogan bool is_create);
186ac27a0ecSDave Kleikamp
187e50e5129SAndreas Dilger extern int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode,
18830a7eb97STahsin Erdogan struct ext4_xattr_inode_array **array,
18930a7eb97STahsin Erdogan int extra_credits);
1900421a189STahsin Erdogan extern void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *array);
191ac27a0ecSDave Kleikamp
1926dd4ee7cSKalpak Shah extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
1936dd4ee7cSKalpak Shah struct ext4_inode *raw_inode, handle_t *handle);
194*6bc0d63dSJan Kara extern void ext4_evict_ea_inode(struct inode *inode);
1956dd4ee7cSKalpak Shah
19611e27528SStephen Hemminger extern const struct xattr_handler *ext4_xattr_handlers[];
197ac27a0ecSDave Kleikamp
198879b3825STao Ma extern int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
199879b3825STao Ma struct ext4_xattr_ibody_find *is);
200879b3825STao Ma extern int ext4_xattr_ibody_get(struct inode *inode, int name_index,
201879b3825STao Ma const char *name,
202879b3825STao Ma void *buffer, size_t buffer_size);
203310c097cSRitesh Harjani extern int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
204879b3825STao Ma struct ext4_xattr_info *i,
205879b3825STao Ma struct ext4_xattr_ibody_find *is);
206879b3825STao Ma
2077a2508e1SJan Kara extern struct mb_cache *ext4_xattr_create_cache(void);
2087a2508e1SJan Kara extern void ext4_xattr_destroy_cache(struct mb_cache *);
2099c191f70ST Makphaibulchoke
21003010a33STheodore Ts'o #ifdef CONFIG_EXT4_FS_SECURITY
211617ba13bSMingming Cao extern int ext4_init_security(handle_t *handle, struct inode *inode,
2122a7dba39SEric Paris struct inode *dir, const struct qstr *qstr);
213ac27a0ecSDave Kleikamp #else
ext4_init_security(handle_t * handle,struct inode * inode,struct inode * dir,const struct qstr * qstr)214617ba13bSMingming Cao static inline int ext4_init_security(handle_t *handle, struct inode *inode,
2152a7dba39SEric Paris struct inode *dir, const struct qstr *qstr)
216ac27a0ecSDave Kleikamp {
217ac27a0ecSDave Kleikamp return 0;
218ac27a0ecSDave Kleikamp }
219ac27a0ecSDave Kleikamp #endif
22033d201e0STahsin Erdogan
22133d201e0STahsin Erdogan #ifdef CONFIG_LOCKDEP
22233d201e0STahsin Erdogan extern void ext4_xattr_inode_set_class(struct inode *ea_inode);
22333d201e0STahsin Erdogan #else
ext4_xattr_inode_set_class(struct inode * ea_inode)22433d201e0STahsin Erdogan static inline void ext4_xattr_inode_set_class(struct inode *ea_inode) { }
22533d201e0STahsin Erdogan #endif
2267a9ca53aSTahsin Erdogan
2277a9ca53aSTahsin Erdogan extern int ext4_get_inode_usage(struct inode *inode, qsize_t *usage);
228