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1/* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */2/*3 * EROFS (Enhanced ROM File System) on-disk format definition4 *5 * Copyright (C) 2017-2018 HUAWEI, Inc.6 * https://www.huawei.com/7 * Copyright (C) 2021, Alibaba Cloud8 */9#ifndef __EROFS_FS_H10#define __EROFS_FS_H11 12#define EROFS_SUPER_OFFSET 102413 14#define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x0000000115#define EROFS_FEATURE_COMPAT_MTIME 0x0000000216#define EROFS_FEATURE_COMPAT_XATTR_FILTER 0x0000000417 18/*19 * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should20 * be incompatible with this kernel version.21 */22#define EROFS_FEATURE_INCOMPAT_ZERO_PADDING 0x0000000123#define EROFS_FEATURE_INCOMPAT_COMPR_CFGS 0x0000000224#define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER 0x0000000225#define EROFS_FEATURE_INCOMPAT_CHUNKED_FILE 0x0000000426#define EROFS_FEATURE_INCOMPAT_DEVICE_TABLE 0x0000000827#define EROFS_FEATURE_INCOMPAT_COMPR_HEAD2 0x0000000828#define EROFS_FEATURE_INCOMPAT_ZTAILPACKING 0x0000001029#define EROFS_FEATURE_INCOMPAT_FRAGMENTS 0x0000002030#define EROFS_FEATURE_INCOMPAT_DEDUPE 0x0000002031#define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES 0x0000004032#define EROFS_ALL_FEATURE_INCOMPAT \33 (EROFS_FEATURE_INCOMPAT_ZERO_PADDING | \34 EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \35 EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER | \36 EROFS_FEATURE_INCOMPAT_CHUNKED_FILE | \37 EROFS_FEATURE_INCOMPAT_DEVICE_TABLE | \38 EROFS_FEATURE_INCOMPAT_COMPR_HEAD2 | \39 EROFS_FEATURE_INCOMPAT_ZTAILPACKING | \40 EROFS_FEATURE_INCOMPAT_FRAGMENTS | \41 EROFS_FEATURE_INCOMPAT_DEDUPE | \42 EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES)43 44#define EROFS_SB_EXTSLOT_SIZE 1645 46struct erofs_deviceslot {47 u8 tag[64]; /* digest(sha256), etc. */48 __le32 blocks; /* total fs blocks of this device */49 __le32 mapped_blkaddr; /* map starting at mapped_blkaddr */50 u8 reserved[56];51};52#define EROFS_DEVT_SLOT_SIZE sizeof(struct erofs_deviceslot)53 54/* erofs on-disk super block (currently 128 bytes) */55struct erofs_super_block {56 __le32 magic; /* file system magic number */57 __le32 checksum; /* crc32c(super_block) */58 __le32 feature_compat;59 __u8 blkszbits; /* filesystem block size in bit shift */60 __u8 sb_extslots; /* superblock size = 128 + sb_extslots * 16 */61 62 __le16 root_nid; /* nid of root directory */63 __le64 inos; /* total valid ino # (== f_files - f_favail) */64 65 __le64 build_time; /* compact inode time derivation */66 __le32 build_time_nsec; /* compact inode time derivation in ns scale */67 __le32 blocks; /* used for statfs */68 __le32 meta_blkaddr; /* start block address of metadata area */69 __le32 xattr_blkaddr; /* start block address of shared xattr area */70 __u8 uuid[16]; /* 128-bit uuid for volume */71 __u8 volume_name[16]; /* volume name */72 __le32 feature_incompat;73 union {74 /* bitmap for available compression algorithms */75 __le16 available_compr_algs;76 /* customized sliding window size instead of 64k by default */77 __le16 lz4_max_distance;78 } __packed u1;79 __le16 extra_devices; /* # of devices besides the primary device */80 __le16 devt_slotoff; /* startoff = devt_slotoff * devt_slotsize */81 __u8 dirblkbits; /* directory block size in bit shift */82 __u8 xattr_prefix_count; /* # of long xattr name prefixes */83 __le32 xattr_prefix_start; /* start of long xattr prefixes */84 __le64 packed_nid; /* nid of the special packed inode */85 __u8 xattr_filter_reserved; /* reserved for xattr name filter */86 __u8 reserved2[23];87};88 89/*90 * EROFS inode datalayout (i_format in on-disk inode):91 * 0 - uncompressed flat inode without tail-packing inline data:92 * 1 - compressed inode with non-compact indexes:93 * 2 - uncompressed flat inode with tail-packing inline data:94 * 3 - compressed inode with compact indexes:95 * 4 - chunk-based inode with (optional) multi-device support:96 * 5~7 - reserved97 */98enum {99 EROFS_INODE_FLAT_PLAIN = 0,100 EROFS_INODE_COMPRESSED_FULL = 1,101 EROFS_INODE_FLAT_INLINE = 2,102 EROFS_INODE_COMPRESSED_COMPACT = 3,103 EROFS_INODE_CHUNK_BASED = 4,104 EROFS_INODE_DATALAYOUT_MAX105};106 107static inline bool erofs_inode_is_data_compressed(unsigned int datamode)108{109 return datamode == EROFS_INODE_COMPRESSED_COMPACT ||110 datamode == EROFS_INODE_COMPRESSED_FULL;111}112 113/* bit definitions of inode i_format */114#define EROFS_I_VERSION_MASK 0x01115#define EROFS_I_DATALAYOUT_MASK 0x07116 117#define EROFS_I_VERSION_BIT 0118#define EROFS_I_DATALAYOUT_BIT 1119#define EROFS_I_ALL_BIT 4120 121#define EROFS_I_ALL ((1 << EROFS_I_ALL_BIT) - 1)122 123/* indicate chunk blkbits, thus 'chunksize = blocksize << chunk blkbits' */124#define EROFS_CHUNK_FORMAT_BLKBITS_MASK 0x001F125/* with chunk indexes or just a 4-byte blkaddr array */126#define EROFS_CHUNK_FORMAT_INDEXES 0x0020127 128#define EROFS_CHUNK_FORMAT_ALL \129 (EROFS_CHUNK_FORMAT_BLKBITS_MASK | EROFS_CHUNK_FORMAT_INDEXES)130 131/* 32-byte on-disk inode */132#define EROFS_INODE_LAYOUT_COMPACT 0133/* 64-byte on-disk inode */134#define EROFS_INODE_LAYOUT_EXTENDED 1135 136struct erofs_inode_chunk_info {137 __le16 format; /* chunk blkbits, etc. */138 __le16 reserved;139};140 141union erofs_inode_i_u {142 /* total compressed blocks for compressed inodes */143 __le32 compressed_blocks;144 145 /* block address for uncompressed flat inodes */146 __le32 raw_blkaddr;147 148 /* for device files, used to indicate old/new device # */149 __le32 rdev;150 151 /* for chunk-based files, it contains the summary info */152 struct erofs_inode_chunk_info c;153};154 155/* 32-byte reduced form of an ondisk inode */156struct erofs_inode_compact {157 __le16 i_format; /* inode format hints */158 159/* 1 header + n-1 * 4 bytes inline xattr to keep continuity */160 __le16 i_xattr_icount;161 __le16 i_mode;162 __le16 i_nlink;163 __le32 i_size;164 __le32 i_reserved;165 union erofs_inode_i_u i_u;166 167 __le32 i_ino; /* only used for 32-bit stat compatibility */168 __le16 i_uid;169 __le16 i_gid;170 __le32 i_reserved2;171};172 173/* 64-byte complete form of an ondisk inode */174struct erofs_inode_extended {175 __le16 i_format; /* inode format hints */176 177/* 1 header + n-1 * 4 bytes inline xattr to keep continuity */178 __le16 i_xattr_icount;179 __le16 i_mode;180 __le16 i_reserved;181 __le64 i_size;182 union erofs_inode_i_u i_u;183 184 __le32 i_ino; /* only used for 32-bit stat compatibility */185 __le32 i_uid;186 __le32 i_gid;187 __le64 i_mtime;188 __le32 i_mtime_nsec;189 __le32 i_nlink;190 __u8 i_reserved2[16];191};192 193/*194 * inline xattrs (n == i_xattr_icount):195 * erofs_xattr_ibody_header(1) + (n - 1) * 4 bytes196 * 12 bytes / \197 * / \198 * /-----------------------\199 * | erofs_xattr_entries+ |200 * +-----------------------+201 * inline xattrs must starts in erofs_xattr_ibody_header,202 * for read-only fs, no need to introduce h_refcount203 */204struct erofs_xattr_ibody_header {205 __le32 h_name_filter; /* bit value 1 indicates not-present */206 __u8 h_shared_count;207 __u8 h_reserved2[7];208 __le32 h_shared_xattrs[]; /* shared xattr id array */209};210 211/* Name indexes */212#define EROFS_XATTR_INDEX_USER 1213#define EROFS_XATTR_INDEX_POSIX_ACL_ACCESS 2214#define EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT 3215#define EROFS_XATTR_INDEX_TRUSTED 4216#define EROFS_XATTR_INDEX_LUSTRE 5217#define EROFS_XATTR_INDEX_SECURITY 6218 219/*220 * bit 7 of e_name_index is set when it refers to a long xattr name prefix,221 * while the remained lower bits represent the index of the prefix.222 */223#define EROFS_XATTR_LONG_PREFIX 0x80224#define EROFS_XATTR_LONG_PREFIX_MASK 0x7f225 226#define EROFS_XATTR_FILTER_BITS 32227#define EROFS_XATTR_FILTER_DEFAULT UINT32_MAX228#define EROFS_XATTR_FILTER_SEED 0x25BBE08F229 230/* xattr entry (for both inline & shared xattrs) */231struct erofs_xattr_entry {232 __u8 e_name_len; /* length of name */233 __u8 e_name_index; /* attribute name index */234 __le16 e_value_size; /* size of attribute value */235 /* followed by e_name and e_value */236 char e_name[]; /* attribute name */237};238 239/* long xattr name prefix */240struct erofs_xattr_long_prefix {241 __u8 base_index; /* short xattr name prefix index */242 char infix[]; /* infix apart from short prefix */243};244 245static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount)246{247 if (!i_xattr_icount)248 return 0;249 250 return sizeof(struct erofs_xattr_ibody_header) +251 sizeof(__u32) * (le16_to_cpu(i_xattr_icount) - 1);252}253 254#define EROFS_XATTR_ALIGN(size) round_up(size, sizeof(struct erofs_xattr_entry))255 256static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e)257{258 return EROFS_XATTR_ALIGN(sizeof(struct erofs_xattr_entry) +259 e->e_name_len + le16_to_cpu(e->e_value_size));260}261 262/* represent a zeroed chunk (hole) */263#define EROFS_NULL_ADDR -1264 265/* 4-byte block address array */266#define EROFS_BLOCK_MAP_ENTRY_SIZE sizeof(__le32)267 268/* 8-byte inode chunk indexes */269struct erofs_inode_chunk_index {270 __le16 advise; /* always 0, don't care for now */271 __le16 device_id; /* back-end storage id (with bits masked) */272 __le32 blkaddr; /* start block address of this inode chunk */273};274 275/* dirent sorts in alphabet order, thus we can do binary search */276struct erofs_dirent {277 __le64 nid; /* node number */278 __le16 nameoff; /* start offset of file name */279 __u8 file_type; /* file type */280 __u8 reserved; /* reserved */281} __packed;282 283/*284 * EROFS file types should match generic FT_* types and285 * it seems no need to add BUILD_BUG_ONs since potential286 * unmatchness will break other fses as well...287 */288 289#define EROFS_NAME_LEN 255290 291/* maximum supported encoded size of a physical compressed cluster */292#define Z_EROFS_PCLUSTER_MAX_SIZE (1024 * 1024)293 294/* maximum supported decoded size of a physical compressed cluster */295#define Z_EROFS_PCLUSTER_MAX_DSIZE (12 * 1024 * 1024)296 297/* available compression algorithm types (for h_algorithmtype) */298enum {299 Z_EROFS_COMPRESSION_LZ4 = 0,300 Z_EROFS_COMPRESSION_LZMA = 1,301 Z_EROFS_COMPRESSION_DEFLATE = 2,302 Z_EROFS_COMPRESSION_ZSTD = 3,303 Z_EROFS_COMPRESSION_MAX304};305#define Z_EROFS_ALL_COMPR_ALGS ((1 << Z_EROFS_COMPRESSION_MAX) - 1)306 307/* 14 bytes (+ length field = 16 bytes) */308struct z_erofs_lz4_cfgs {309 __le16 max_distance;310 __le16 max_pclusterblks;311 u8 reserved[10];312} __packed;313 314/* 14 bytes (+ length field = 16 bytes) */315struct z_erofs_lzma_cfgs {316 __le32 dict_size;317 __le16 format;318 u8 reserved[8];319} __packed;320 321#define Z_EROFS_LZMA_MAX_DICT_SIZE (8 * Z_EROFS_PCLUSTER_MAX_SIZE)322 323/* 6 bytes (+ length field = 8 bytes) */324struct z_erofs_deflate_cfgs {325 u8 windowbits; /* 8..15 for DEFLATE */326 u8 reserved[5];327} __packed;328 329/* 6 bytes (+ length field = 8 bytes) */330struct z_erofs_zstd_cfgs {331 u8 format;332 u8 windowlog; /* windowLog - ZSTD_WINDOWLOG_ABSOLUTEMIN(10) */333 u8 reserved[4];334} __packed;335 336#define Z_EROFS_ZSTD_MAX_DICT_SIZE Z_EROFS_PCLUSTER_MAX_SIZE337 338/*339 * bit 0 : COMPACTED_2B indexes (0 - off; 1 - on)340 * e.g. for 4k logical cluster size, 4B if compacted 2B is off;341 * (4B) + 2B + (4B) if compacted 2B is on.342 * bit 1 : HEAD1 big pcluster (0 - off; 1 - on)343 * bit 2 : HEAD2 big pcluster (0 - off; 1 - on)344 * bit 3 : tailpacking inline pcluster (0 - off; 1 - on)345 * bit 4 : interlaced plain pcluster (0 - off; 1 - on)346 * bit 5 : fragment pcluster (0 - off; 1 - on)347 */348#define Z_EROFS_ADVISE_COMPACTED_2B 0x0001349#define Z_EROFS_ADVISE_BIG_PCLUSTER_1 0x0002350#define Z_EROFS_ADVISE_BIG_PCLUSTER_2 0x0004351#define Z_EROFS_ADVISE_INLINE_PCLUSTER 0x0008352#define Z_EROFS_ADVISE_INTERLACED_PCLUSTER 0x0010353#define Z_EROFS_ADVISE_FRAGMENT_PCLUSTER 0x0020354 355#define Z_EROFS_FRAGMENT_INODE_BIT 7356struct z_erofs_map_header {357 union {358 /* fragment data offset in the packed inode */359 __le32 h_fragmentoff;360 struct {361 __le16 h_reserved1;362 /* indicates the encoded size of tailpacking data */363 __le16 h_idata_size;364 };365 };366 __le16 h_advise;367 /*368 * bit 0-3 : algorithm type of head 1 (logical cluster type 01);369 * bit 4-7 : algorithm type of head 2 (logical cluster type 11).370 */371 __u8 h_algorithmtype;372 /*373 * bit 0-2 : logical cluster bits - 12, e.g. 0 for 4096;374 * bit 3-6 : reserved;375 * bit 7 : move the whole file into packed inode or not.376 */377 __u8 h_clusterbits;378};379 380/*381 * On-disk logical cluster type:382 * 0 - literal (uncompressed) lcluster383 * 1,3 - compressed lcluster (for HEAD lclusters)384 * 2 - compressed lcluster (for NONHEAD lclusters)385 *386 * In detail,387 * 0 - literal (uncompressed) lcluster,388 * di_advise = 0389 * di_clusterofs = the literal data offset of the lcluster390 * di_blkaddr = the blkaddr of the literal pcluster391 *392 * 1,3 - compressed lcluster (for HEAD lclusters)393 * di_advise = 1 or 3394 * di_clusterofs = the decompressed data offset of the lcluster395 * di_blkaddr = the blkaddr of the compressed pcluster396 *397 * 2 - compressed lcluster (for NONHEAD lclusters)398 * di_advise = 2399 * di_clusterofs =400 * the decompressed data offset in its own HEAD lcluster401 * di_u.delta[0] = distance to this HEAD lcluster402 * di_u.delta[1] = distance to the next HEAD lcluster403 */404enum {405 Z_EROFS_LCLUSTER_TYPE_PLAIN = 0,406 Z_EROFS_LCLUSTER_TYPE_HEAD1 = 1,407 Z_EROFS_LCLUSTER_TYPE_NONHEAD = 2,408 Z_EROFS_LCLUSTER_TYPE_HEAD2 = 3,409 Z_EROFS_LCLUSTER_TYPE_MAX410};411 412#define Z_EROFS_LI_LCLUSTER_TYPE_MASK (Z_EROFS_LCLUSTER_TYPE_MAX - 1)413 414/* (noncompact only, HEAD) This pcluster refers to partial decompressed data */415#define Z_EROFS_LI_PARTIAL_REF (1 << 15)416 417/*418 * D0_CBLKCNT will be marked _only_ at the 1st non-head lcluster to store the419 * compressed block count of a compressed extent (in logical clusters, aka.420 * block count of a pcluster).421 */422#define Z_EROFS_LI_D0_CBLKCNT (1 << 11)423 424struct z_erofs_lcluster_index {425 __le16 di_advise;426 /* where to decompress in the head lcluster */427 __le16 di_clusterofs;428 429 union {430 /* for the HEAD lclusters */431 __le32 blkaddr;432 /*433 * for the NONHEAD lclusters434 * [0] - distance to its HEAD lcluster435 * [1] - distance to the next HEAD lcluster436 */437 __le16 delta[2];438 } di_u;439};440 441#define Z_EROFS_FULL_INDEX_ALIGN(end) \442 (ALIGN(end, 8) + sizeof(struct z_erofs_map_header) + 8)443 444/* check the EROFS on-disk layout strictly at compile time */445static inline void erofs_check_ondisk_layout_definitions(void)446{447 const __le64 fmh = *(__le64 *)&(struct z_erofs_map_header) {448 .h_clusterbits = 1 << Z_EROFS_FRAGMENT_INODE_BIT449 };450 451 BUILD_BUG_ON(sizeof(struct erofs_super_block) != 128);452 BUILD_BUG_ON(sizeof(struct erofs_inode_compact) != 32);453 BUILD_BUG_ON(sizeof(struct erofs_inode_extended) != 64);454 BUILD_BUG_ON(sizeof(struct erofs_xattr_ibody_header) != 12);455 BUILD_BUG_ON(sizeof(struct erofs_xattr_entry) != 4);456 BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_info) != 4);457 BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_index) != 8);458 BUILD_BUG_ON(sizeof(struct z_erofs_map_header) != 8);459 BUILD_BUG_ON(sizeof(struct z_erofs_lcluster_index) != 8);460 BUILD_BUG_ON(sizeof(struct erofs_dirent) != 12);461 /* keep in sync between 2 index structures for better extendibility */462 BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_index) !=463 sizeof(struct z_erofs_lcluster_index));464 BUILD_BUG_ON(sizeof(struct erofs_deviceslot) != 128);465 466 /* exclude old compiler versions like gcc 7.5.0 */467 BUILD_BUG_ON(__builtin_constant_p(fmh) ?468 fmh != cpu_to_le64(1ULL << 63) : 0);469}470 471#endif472