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29b24f6c GX |
1 | /* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */ |
2 | /* | |
ea559e7b GX |
3 | * EROFS (Enhanced ROM File System) on-disk format definition |
4 | * | |
aea1286d GX |
5 | * Copyright (C) 2017-2018 HUAWEI, Inc. |
6 | * http://www.huawei.com/ | |
7 | * Created by Gao Xiang <gaoxiang25@huawei.com> | |
aea1286d GX |
8 | */ |
9 | #ifndef __EROFS_FS_H | |
10 | #define __EROFS_FS_H | |
11 | ||
aea1286d GX |
12 | #define EROFS_SUPER_OFFSET 1024 |
13 | ||
b858a484 PS |
14 | #define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001 |
15 | ||
5efe5137 | 16 | /* |
426a9308 GX |
17 | * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should |
18 | * be incompatible with this kernel version. | |
5efe5137 | 19 | */ |
426a9308 GX |
20 | #define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING 0x00000001 |
21 | #define EROFS_ALL_FEATURE_INCOMPAT EROFS_FEATURE_INCOMPAT_LZ4_0PADDING | |
5efe5137 | 22 | |
4b66eb51 | 23 | /* 128-byte erofs on-disk super block */ |
aea1286d | 24 | struct erofs_super_block { |
4b66eb51 GX |
25 | __le32 magic; /* file system magic number */ |
26 | __le32 checksum; /* crc32c(super_block) */ | |
426a9308 | 27 | __le32 feature_compat; |
4b66eb51 GX |
28 | __u8 blkszbits; /* support block_size == PAGE_SIZE only */ |
29 | __u8 reserved; | |
30 | ||
31 | __le16 root_nid; /* nid of root directory */ | |
32 | __le64 inos; /* total valid ino # (== f_files - f_favail) */ | |
33 | ||
34 | __le64 build_time; /* inode v1 time derivation */ | |
35 | __le32 build_time_nsec; /* inode v1 time derivation in nano scale */ | |
36 | __le32 blocks; /* used for statfs */ | |
37 | __le32 meta_blkaddr; /* start block address of metadata area */ | |
38 | __le32 xattr_blkaddr; /* start block address of shared xattr area */ | |
39 | __u8 uuid[16]; /* 128-bit uuid for volume */ | |
40 | __u8 volume_name[16]; /* volume name */ | |
426a9308 | 41 | __le32 feature_incompat; |
4b66eb51 | 42 | __u8 reserved2[44]; |
ed34aa4a | 43 | }; |
aea1286d | 44 | |
aea1286d | 45 | /* |
ea559e7b | 46 | * erofs inode datalayout (i_format in on-disk inode): |
aea1286d GX |
47 | * 0 - inode plain without inline data A: |
48 | * inode, [xattrs], ... | ... | no-holed data | |
ec8c2442 | 49 | * 1 - inode VLE compression B (legacy): |
aea1286d GX |
50 | * inode, [xattrs], extents ... | ... |
51 | * 2 - inode plain with inline data C: | |
52 | * inode, [xattrs], last_inline_data, ... | ... | no-holed data | |
ec8c2442 GX |
53 | * 3 - inode compression D: |
54 | * inode, [xattrs], map_header, extents ... | ... | |
55 | * 4~7 - reserved | |
aea1286d GX |
56 | */ |
57 | enum { | |
60a49ba8 GX |
58 | EROFS_INODE_FLAT_PLAIN = 0, |
59 | EROFS_INODE_FLAT_COMPRESSION_LEGACY = 1, | |
60 | EROFS_INODE_FLAT_INLINE = 2, | |
61 | EROFS_INODE_FLAT_COMPRESSION = 3, | |
8a765682 | 62 | EROFS_INODE_DATALAYOUT_MAX |
aea1286d | 63 | }; |
ccd9c19c | 64 | |
3d2969fa | 65 | static inline bool erofs_inode_is_data_compressed(unsigned int datamode) |
ec8c2442 | 66 | { |
c39747f7 GX |
67 | return datamode == EROFS_INODE_FLAT_COMPRESSION || |
68 | datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY; | |
ec8c2442 GX |
69 | } |
70 | ||
ccd9c19c | 71 | /* bit definitions of inode i_advise */ |
aea1286d | 72 | #define EROFS_I_VERSION_BITS 1 |
8a765682 | 73 | #define EROFS_I_DATALAYOUT_BITS 3 |
aea1286d GX |
74 | |
75 | #define EROFS_I_VERSION_BIT 0 | |
8a765682 | 76 | #define EROFS_I_DATALAYOUT_BIT 1 |
aea1286d | 77 | |
4b66eb51 | 78 | /* 32-byte reduced form of an ondisk inode */ |
8a765682 GX |
79 | struct erofs_inode_compact { |
80 | __le16 i_format; /* inode format hints */ | |
aea1286d GX |
81 | |
82 | /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */ | |
4b66eb51 GX |
83 | __le16 i_xattr_icount; |
84 | __le16 i_mode; | |
85 | __le16 i_nlink; | |
86 | __le32 i_size; | |
87 | __le32 i_reserved; | |
88 | union { | |
aea1286d GX |
89 | /* file total compressed blocks for data mapping 1 */ |
90 | __le32 compressed_blocks; | |
91 | __le32 raw_blkaddr; | |
92 | ||
93 | /* for device files, used to indicate old/new device # */ | |
94 | __le32 rdev; | |
ed34aa4a | 95 | } i_u; |
4b66eb51 GX |
96 | __le32 i_ino; /* only used for 32-bit stat compatibility */ |
97 | __le16 i_uid; | |
98 | __le16 i_gid; | |
99 | __le32 i_reserved2; | |
ed34aa4a | 100 | }; |
aea1286d GX |
101 | |
102 | /* 32 bytes on-disk inode */ | |
8a765682 | 103 | #define EROFS_INODE_LAYOUT_COMPACT 0 |
aea1286d | 104 | /* 64 bytes on-disk inode */ |
8a765682 | 105 | #define EROFS_INODE_LAYOUT_EXTENDED 1 |
aea1286d | 106 | |
4b66eb51 | 107 | /* 64-byte complete form of an ondisk inode */ |
8a765682 GX |
108 | struct erofs_inode_extended { |
109 | __le16 i_format; /* inode format hints */ | |
cead56f8 GX |
110 | |
111 | /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */ | |
4b66eb51 GX |
112 | __le16 i_xattr_icount; |
113 | __le16 i_mode; | |
114 | __le16 i_reserved; | |
115 | __le64 i_size; | |
116 | union { | |
aea1286d GX |
117 | /* file total compressed blocks for data mapping 1 */ |
118 | __le32 compressed_blocks; | |
119 | __le32 raw_blkaddr; | |
120 | ||
121 | /* for device files, used to indicate old/new device # */ | |
122 | __le32 rdev; | |
ed34aa4a | 123 | } i_u; |
aea1286d GX |
124 | |
125 | /* only used for 32-bit stat compatibility */ | |
4b66eb51 GX |
126 | __le32 i_ino; |
127 | ||
128 | __le32 i_uid; | |
129 | __le32 i_gid; | |
130 | __le64 i_ctime; | |
131 | __le32 i_ctime_nsec; | |
132 | __le32 i_nlink; | |
133 | __u8 i_reserved2[16]; | |
ed34aa4a | 134 | }; |
aea1286d GX |
135 | |
136 | #define EROFS_MAX_SHARED_XATTRS (128) | |
137 | /* h_shared_count between 129 ... 255 are special # */ | |
138 | #define EROFS_SHARED_XATTR_EXTENT (255) | |
139 | ||
140 | /* | |
141 | * inline xattrs (n == i_xattr_icount): | |
142 | * erofs_xattr_ibody_header(1) + (n - 1) * 4 bytes | |
143 | * 12 bytes / \ | |
144 | * / \ | |
145 | * /-----------------------\ | |
146 | * | erofs_xattr_entries+ | | |
147 | * +-----------------------+ | |
148 | * inline xattrs must starts in erofs_xattr_ibody_header, | |
149 | * for read-only fs, no need to introduce h_refcount | |
150 | */ | |
151 | struct erofs_xattr_ibody_header { | |
cead56f8 | 152 | __le32 h_reserved; |
aea1286d | 153 | __u8 h_shared_count; |
cead56f8 | 154 | __u8 h_reserved2[7]; |
aea1286d | 155 | __le32 h_shared_xattrs[0]; /* shared xattr id array */ |
ed34aa4a | 156 | }; |
aea1286d GX |
157 | |
158 | /* Name indexes */ | |
159 | #define EROFS_XATTR_INDEX_USER 1 | |
160 | #define EROFS_XATTR_INDEX_POSIX_ACL_ACCESS 2 | |
161 | #define EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT 3 | |
162 | #define EROFS_XATTR_INDEX_TRUSTED 4 | |
163 | #define EROFS_XATTR_INDEX_LUSTRE 5 | |
164 | #define EROFS_XATTR_INDEX_SECURITY 6 | |
165 | ||
166 | /* xattr entry (for both inline & shared xattrs) */ | |
167 | struct erofs_xattr_entry { | |
168 | __u8 e_name_len; /* length of name */ | |
169 | __u8 e_name_index; /* attribute name index */ | |
170 | __le16 e_value_size; /* size of attribute value */ | |
171 | /* followed by e_name and e_value */ | |
172 | char e_name[0]; /* attribute name */ | |
ed34aa4a | 173 | }; |
aea1286d | 174 | |
b6796abd GX |
175 | static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount) |
176 | { | |
177 | if (!i_xattr_icount) | |
178 | return 0; | |
179 | ||
180 | return sizeof(struct erofs_xattr_ibody_header) + | |
181 | sizeof(__u32) * (le16_to_cpu(i_xattr_icount) - 1); | |
182 | } | |
aea1286d GX |
183 | |
184 | #define EROFS_XATTR_ALIGN(size) round_up(size, sizeof(struct erofs_xattr_entry)) | |
b6796abd GX |
185 | |
186 | static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e) | |
187 | { | |
188 | return EROFS_XATTR_ALIGN(sizeof(struct erofs_xattr_entry) + | |
189 | e->e_name_len + le16_to_cpu(e->e_value_size)); | |
190 | } | |
aea1286d | 191 | |
ea559e7b | 192 | /* available compression algorithm types (for h_algorithmtype) */ |
ec8c2442 | 193 | enum { |
60a49ba8 | 194 | Z_EROFS_COMPRESSION_LZ4 = 0, |
ec8c2442 GX |
195 | Z_EROFS_COMPRESSION_MAX |
196 | }; | |
197 | ||
198 | /* | |
199 | * bit 0 : COMPACTED_2B indexes (0 - off; 1 - on) | |
200 | * e.g. for 4k logical cluster size, 4B if compacted 2B is off; | |
201 | * (4B) + 2B + (4B) if compacted 2B is on. | |
202 | */ | |
203 | #define Z_EROFS_ADVISE_COMPACTED_2B_BIT 0 | |
204 | ||
205 | #define Z_EROFS_ADVISE_COMPACTED_2B (1 << Z_EROFS_ADVISE_COMPACTED_2B_BIT) | |
206 | ||
207 | struct z_erofs_map_header { | |
208 | __le32 h_reserved1; | |
209 | __le16 h_advise; | |
210 | /* | |
211 | * bit 0-3 : algorithm type of head 1 (logical cluster type 01); | |
212 | * bit 4-7 : algorithm type of head 2 (logical cluster type 11). | |
213 | */ | |
214 | __u8 h_algorithmtype; | |
215 | /* | |
216 | * bit 0-2 : logical cluster bits - 12, e.g. 0 for 4096; | |
217 | * bit 3-4 : (physical - logical) cluster bits of head 1: | |
218 | * For example, if logical clustersize = 4096, 1 for 8192. | |
219 | * bit 5-7 : (physical - logical) cluster bits of head 2. | |
220 | */ | |
221 | __u8 h_clusterbits; | |
222 | }; | |
223 | ||
224 | #define Z_EROFS_VLE_LEGACY_HEADER_PADDING 8 | |
aea1286d GX |
225 | |
226 | /* | |
ea559e7b | 227 | * Fixed-sized output compression ondisk Logical Extent cluster type: |
aea1286d GX |
228 | * 0 - literal (uncompressed) cluster |
229 | * 1 - compressed cluster (for the head logical cluster) | |
230 | * 2 - compressed cluster (for the other logical clusters) | |
231 | * | |
232 | * In detail, | |
233 | * 0 - literal (uncompressed) cluster, | |
234 | * di_advise = 0 | |
235 | * di_clusterofs = the literal data offset of the cluster | |
236 | * di_blkaddr = the blkaddr of the literal cluster | |
237 | * | |
238 | * 1 - compressed cluster (for the head logical cluster) | |
239 | * di_advise = 1 | |
240 | * di_clusterofs = the decompressed data offset of the cluster | |
241 | * di_blkaddr = the blkaddr of the compressed cluster | |
242 | * | |
243 | * 2 - compressed cluster (for the other logical clusters) | |
244 | * di_advise = 2 | |
245 | * di_clusterofs = | |
246 | * the decompressed data offset in its own head cluster | |
247 | * di_u.delta[0] = distance to its corresponding head cluster | |
248 | * di_u.delta[1] = distance to its corresponding tail cluster | |
249 | * (di_advise could be 0, 1 or 2) | |
250 | */ | |
99691b46 | 251 | enum { |
60a49ba8 GX |
252 | Z_EROFS_VLE_CLUSTER_TYPE_PLAIN = 0, |
253 | Z_EROFS_VLE_CLUSTER_TYPE_HEAD = 1, | |
254 | Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD = 2, | |
255 | Z_EROFS_VLE_CLUSTER_TYPE_RESERVED = 3, | |
99691b46 GX |
256 | Z_EROFS_VLE_CLUSTER_TYPE_MAX |
257 | }; | |
258 | ||
aea1286d GX |
259 | #define Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS 2 |
260 | #define Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT 0 | |
261 | ||
262 | struct z_erofs_vle_decompressed_index { | |
263 | __le16 di_advise; | |
264 | /* where to decompress in the head cluster */ | |
265 | __le16 di_clusterofs; | |
266 | ||
267 | union { | |
268 | /* for the head cluster */ | |
269 | __le32 blkaddr; | |
270 | /* | |
271 | * for the rest clusters | |
272 | * eg. for 4k page-sized cluster, maximum 4K*64k = 256M) | |
273 | * [0] - pointing to the head cluster | |
274 | * [1] - pointing to the tail cluster | |
275 | */ | |
276 | __le16 delta[2]; | |
ed34aa4a GX |
277 | } di_u; |
278 | }; | |
aea1286d | 279 | |
ec8c2442 GX |
280 | #define Z_EROFS_VLE_LEGACY_INDEX_ALIGN(size) \ |
281 | (round_up(size, sizeof(struct z_erofs_vle_decompressed_index)) + \ | |
282 | sizeof(struct z_erofs_map_header) + Z_EROFS_VLE_LEGACY_HEADER_PADDING) | |
aea1286d GX |
283 | |
284 | /* dirent sorts in alphabet order, thus we can do binary search */ | |
285 | struct erofs_dirent { | |
4b66eb51 GX |
286 | __le64 nid; /* node number */ |
287 | __le16 nameoff; /* start offset of file name */ | |
288 | __u8 file_type; /* file type */ | |
289 | __u8 reserved; /* reserved */ | |
aea1286d GX |
290 | } __packed; |
291 | ||
1d819c54 GX |
292 | /* |
293 | * EROFS file types should match generic FT_* types and | |
294 | * it seems no need to add BUILD_BUG_ONs since potential | |
295 | * unmatchness will break other fses as well... | |
296 | */ | |
aea1286d GX |
297 | |
298 | #define EROFS_NAME_LEN 255 | |
299 | ||
300 | /* check the EROFS on-disk layout strictly at compile time */ | |
301 | static inline void erofs_check_ondisk_layout_definitions(void) | |
302 | { | |
303 | BUILD_BUG_ON(sizeof(struct erofs_super_block) != 128); | |
8a765682 GX |
304 | BUILD_BUG_ON(sizeof(struct erofs_inode_compact) != 32); |
305 | BUILD_BUG_ON(sizeof(struct erofs_inode_extended) != 64); | |
aea1286d GX |
306 | BUILD_BUG_ON(sizeof(struct erofs_xattr_ibody_header) != 12); |
307 | BUILD_BUG_ON(sizeof(struct erofs_xattr_entry) != 4); | |
ec8c2442 | 308 | BUILD_BUG_ON(sizeof(struct z_erofs_map_header) != 8); |
aea1286d GX |
309 | BUILD_BUG_ON(sizeof(struct z_erofs_vle_decompressed_index) != 8); |
310 | BUILD_BUG_ON(sizeof(struct erofs_dirent) != 12); | |
99691b46 GX |
311 | |
312 | BUILD_BUG_ON(BIT(Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) < | |
313 | Z_EROFS_VLE_CLUSTER_TYPE_MAX - 1); | |
aea1286d GX |
314 | } |
315 | ||
316 | #endif | |
317 |