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Diffstat (limited to 'fs/erofs/erofs_fs.h')
| -rw-r--r-- | fs/erofs/erofs_fs.h | 466 |
1 files changed, 466 insertions, 0 deletions
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h new file mode 100644 index 000000000000..e24268acdd62 --- /dev/null +++ b/fs/erofs/erofs_fs.h @@ -0,0 +1,466 @@ +/* SPDX-License-Identifier: MIT */ +/* + * EROFS (Enhanced ROM File System) on-disk format definition + * + * Copyright (C) 2017-2018 HUAWEI, Inc. + * https://www.huawei.com/ + * Copyright (C) 2021, Alibaba Cloud + */ +#ifndef __EROFS_FS_H +#define __EROFS_FS_H + +/* to allow for x86 boot sectors and other oddities. */ +#define EROFS_SUPER_OFFSET 1024 + +#define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001 +#define EROFS_FEATURE_COMPAT_MTIME 0x00000002 +#define EROFS_FEATURE_COMPAT_XATTR_FILTER 0x00000004 +#define EROFS_FEATURE_COMPAT_SHARED_EA_IN_METABOX 0x00000008 +#define EROFS_FEATURE_COMPAT_PLAIN_XATTR_PFX 0x00000010 + + +/* + * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should + * be incompatible with this kernel version. + */ +#define EROFS_FEATURE_INCOMPAT_ZERO_PADDING 0x00000001 +#define EROFS_FEATURE_INCOMPAT_COMPR_CFGS 0x00000002 +#define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER 0x00000002 +#define EROFS_FEATURE_INCOMPAT_CHUNKED_FILE 0x00000004 +#define EROFS_FEATURE_INCOMPAT_DEVICE_TABLE 0x00000008 +#define EROFS_FEATURE_INCOMPAT_COMPR_HEAD2 0x00000008 +#define EROFS_FEATURE_INCOMPAT_ZTAILPACKING 0x00000010 +#define EROFS_FEATURE_INCOMPAT_FRAGMENTS 0x00000020 +#define EROFS_FEATURE_INCOMPAT_DEDUPE 0x00000020 +#define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES 0x00000040 +#define EROFS_FEATURE_INCOMPAT_48BIT 0x00000080 +#define EROFS_FEATURE_INCOMPAT_METABOX 0x00000100 +#define EROFS_ALL_FEATURE_INCOMPAT \ + ((EROFS_FEATURE_INCOMPAT_METABOX << 1) - 1) + +#define EROFS_SB_EXTSLOT_SIZE 16 + +struct erofs_deviceslot { + u8 tag[64]; /* digest(sha256), etc. */ + __le32 blocks_lo; /* total blocks count of this device */ + __le32 uniaddr_lo; /* unified starting block of this device */ + __le32 blocks_hi; /* total blocks count MSB */ + __le16 uniaddr_hi; /* unified starting block MSB */ + u8 reserved[50]; +}; +#define EROFS_DEVT_SLOT_SIZE sizeof(struct erofs_deviceslot) + +/* erofs on-disk super block (currently 144 bytes at maximum) */ +struct erofs_super_block { + __le32 magic; /* file system magic number */ + __le32 checksum; /* crc32c to avoid unexpected on-disk overlap */ + __le32 feature_compat; + __u8 blkszbits; /* filesystem block size in bit shift */ + __u8 sb_extslots; /* superblock size = 128 + sb_extslots * 16 */ + union { + __le16 rootnid_2b; /* nid of root directory */ + __le16 blocks_hi; /* (48BIT on) blocks count MSB */ + } __packed rb; + __le64 inos; /* total valid ino # (== f_files - f_favail) */ + __le64 epoch; /* base seconds used for compact inodes */ + __le32 fixed_nsec; /* fixed nanoseconds for compact inodes */ + __le32 blocks_lo; /* blocks count LSB */ + __le32 meta_blkaddr; /* start block address of metadata area */ + __le32 xattr_blkaddr; /* start block address of shared xattr area */ + __u8 uuid[16]; /* 128-bit uuid for volume */ + __u8 volume_name[16]; /* volume name */ + __le32 feature_incompat; + union { + /* bitmap for available compression algorithms */ + __le16 available_compr_algs; + /* customized sliding window size instead of 64k by default */ + __le16 lz4_max_distance; + } __packed u1; + __le16 extra_devices; /* # of devices besides the primary device */ + __le16 devt_slotoff; /* startoff = devt_slotoff * devt_slotsize */ + __u8 dirblkbits; /* directory block size in bit shift */ + __u8 xattr_prefix_count; /* # of long xattr name prefixes */ + __le32 xattr_prefix_start; /* start of long xattr prefixes */ + __le64 packed_nid; /* nid of the special packed inode */ + __u8 xattr_filter_reserved; /* reserved for xattr name filter */ + __u8 reserved[3]; + __le32 build_time; /* seconds added to epoch for mkfs time */ + __le64 rootnid_8b; /* (48BIT on) nid of root directory */ + __le64 reserved2; + __le64 metabox_nid; /* (METABOX on) nid of the metabox inode */ + __le64 reserved3; /* [align to extslot 1] */ +}; + +/* + * EROFS inode datalayout (i_format in on-disk inode): + * 0 - uncompressed flat inode without tail-packing inline data: + * 1 - compressed inode with non-compact indexes: + * 2 - uncompressed flat inode with tail-packing inline data: + * 3 - compressed inode with compact indexes: + * 4 - chunk-based inode with (optional) multi-device support: + * 5~7 - reserved + */ +enum { + EROFS_INODE_FLAT_PLAIN = 0, + EROFS_INODE_COMPRESSED_FULL = 1, + EROFS_INODE_FLAT_INLINE = 2, + EROFS_INODE_COMPRESSED_COMPACT = 3, + EROFS_INODE_CHUNK_BASED = 4, + EROFS_INODE_DATALAYOUT_MAX +}; + +static inline bool erofs_inode_is_data_compressed(unsigned int datamode) +{ + return datamode == EROFS_INODE_COMPRESSED_COMPACT || + datamode == EROFS_INODE_COMPRESSED_FULL; +} + +/* bit definitions of inode i_format */ +#define EROFS_I_VERSION_MASK 0x01 +#define EROFS_I_DATALAYOUT_MASK 0x07 + +#define EROFS_I_VERSION_BIT 0 +#define EROFS_I_DATALAYOUT_BIT 1 +#define EROFS_I_NLINK_1_BIT 4 /* non-directory compact inodes only */ +#define EROFS_I_DOT_OMITTED_BIT 4 /* (directories) omit the `.` dirent */ +#define EROFS_I_ALL ((1 << (EROFS_I_NLINK_1_BIT + 1)) - 1) + +/* indicate chunk blkbits, thus 'chunksize = blocksize << chunk blkbits' */ +#define EROFS_CHUNK_FORMAT_BLKBITS_MASK 0x001F +/* with chunk indexes or just a 4-byte block array */ +#define EROFS_CHUNK_FORMAT_INDEXES 0x0020 +#define EROFS_CHUNK_FORMAT_48BIT 0x0040 + +#define EROFS_CHUNK_FORMAT_ALL ((EROFS_CHUNK_FORMAT_48BIT << 1) - 1) + +/* 32-byte on-disk inode */ +#define EROFS_INODE_LAYOUT_COMPACT 0 +/* 64-byte on-disk inode */ +#define EROFS_INODE_LAYOUT_EXTENDED 1 + +struct erofs_inode_chunk_info { + __le16 format; /* chunk blkbits, etc. */ + __le16 reserved; +}; + +union erofs_inode_i_u { + __le32 blocks_lo; /* total blocks count (if compressed inodes) */ + __le32 startblk_lo; /* starting block number (if flat inodes) */ + __le32 rdev; /* device ID (if special inodes) */ + struct erofs_inode_chunk_info c; +}; + +union erofs_inode_i_nb { + __le16 nlink; /* if EROFS_I_NLINK_1_BIT is unset */ + __le16 blocks_hi; /* total blocks count MSB */ + __le16 startblk_hi; /* starting block number MSB */ +} __packed; + +/* 32-byte reduced form of an ondisk inode */ +struct erofs_inode_compact { + __le16 i_format; /* inode format hints */ + __le16 i_xattr_icount; + __le16 i_mode; + union erofs_inode_i_nb i_nb; + __le32 i_size; + __le32 i_mtime; + union erofs_inode_i_u i_u; + + __le32 i_ino; /* only used for 32-bit stat compatibility */ + __le16 i_uid; + __le16 i_gid; + __le32 i_reserved; +}; + +/* 64-byte complete form of an ondisk inode */ +struct erofs_inode_extended { + __le16 i_format; /* inode format hints */ + __le16 i_xattr_icount; + __le16 i_mode; + union erofs_inode_i_nb i_nb; + __le64 i_size; + union erofs_inode_i_u i_u; + + __le32 i_ino; /* only used for 32-bit stat compatibility */ + __le32 i_uid; + __le32 i_gid; + __le64 i_mtime; + __le32 i_mtime_nsec; + __le32 i_nlink; + __u8 i_reserved2[16]; +}; + +/* + * inline xattrs (n == i_xattr_icount): + * erofs_xattr_ibody_header(1) + (n - 1) * 4 bytes + * 12 bytes / \ + * / \ + * /-----------------------\ + * | erofs_xattr_entries+ | + * +-----------------------+ + * inline xattrs must starts in erofs_xattr_ibody_header, + * for read-only fs, no need to introduce h_refcount + */ +struct erofs_xattr_ibody_header { + __le32 h_name_filter; /* bit value 1 indicates not-present */ + __u8 h_shared_count; + __u8 h_reserved2[7]; + __le32 h_shared_xattrs[]; /* shared xattr id array */ +}; + +/* Name indexes */ +#define EROFS_XATTR_INDEX_USER 1 +#define EROFS_XATTR_INDEX_POSIX_ACL_ACCESS 2 +#define EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT 3 +#define EROFS_XATTR_INDEX_TRUSTED 4 +#define EROFS_XATTR_INDEX_LUSTRE 5 +#define EROFS_XATTR_INDEX_SECURITY 6 + +/* + * bit 7 of e_name_index is set when it refers to a long xattr name prefix, + * while the remained lower bits represent the index of the prefix. + */ +#define EROFS_XATTR_LONG_PREFIX 0x80 +#define EROFS_XATTR_LONG_PREFIX_MASK 0x7f + +#define EROFS_XATTR_FILTER_BITS 32 +#define EROFS_XATTR_FILTER_DEFAULT UINT32_MAX +#define EROFS_XATTR_FILTER_SEED 0x25BBE08F + +/* xattr entry (for both inline & shared xattrs) */ +struct erofs_xattr_entry { + __u8 e_name_len; /* length of name */ + __u8 e_name_index; /* attribute name index */ + __le16 e_value_size; /* size of attribute value */ + /* followed by e_name and e_value */ + char e_name[]; /* attribute name */ +}; + +/* long xattr name prefix */ +struct erofs_xattr_long_prefix { + __u8 base_index; /* short xattr name prefix index */ + char infix[]; /* infix apart from short prefix */ +}; + +static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount) +{ + if (!i_xattr_icount) + return 0; + + /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */ + return sizeof(struct erofs_xattr_ibody_header) + + sizeof(__u32) * (le16_to_cpu(i_xattr_icount) - 1); +} + +#define EROFS_XATTR_ALIGN(size) round_up(size, sizeof(struct erofs_xattr_entry)) + +static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e) +{ + return EROFS_XATTR_ALIGN(sizeof(struct erofs_xattr_entry) + + e->e_name_len + le16_to_cpu(e->e_value_size)); +} + +/* represent a zeroed chunk (hole) */ +#define EROFS_NULL_ADDR -1 + +/* 4-byte block address array */ +#define EROFS_BLOCK_MAP_ENTRY_SIZE sizeof(__le32) + +/* 8-byte inode chunk index */ +struct erofs_inode_chunk_index { + __le16 startblk_hi; /* starting block number MSB */ + __le16 device_id; /* back-end storage id (with bits masked) */ + __le32 startblk_lo; /* starting block number of this chunk */ +}; + +#define EROFS_DIRENT_NID_METABOX_BIT 63 +#define EROFS_DIRENT_NID_MASK (BIT_ULL(EROFS_DIRENT_NID_METABOX_BIT) - 1) + +/* dirent sorts in alphabet order, thus we can do binary search */ +struct erofs_dirent { + __le64 nid; /* node number */ + __le16 nameoff; /* start offset of file name */ + __u8 file_type; /* file type */ + __u8 reserved; /* reserved */ +} __packed; + +/* + * EROFS file types should match generic FT_* types and + * it seems no need to add BUILD_BUG_ONs since potential + * unmatchness will break other fses as well... + */ + +#define EROFS_NAME_LEN 255 + +/* maximum supported encoded size of a physical compressed cluster */ +#define Z_EROFS_PCLUSTER_MAX_SIZE (1024 * 1024) + +/* maximum supported decoded size of a physical compressed cluster */ +#define Z_EROFS_PCLUSTER_MAX_DSIZE (12 * 1024 * 1024) + +/* available compression algorithm types (for h_algorithmtype) */ +enum { + Z_EROFS_COMPRESSION_LZ4 = 0, + Z_EROFS_COMPRESSION_LZMA = 1, + Z_EROFS_COMPRESSION_DEFLATE = 2, + Z_EROFS_COMPRESSION_ZSTD = 3, + Z_EROFS_COMPRESSION_MAX +}; +#define Z_EROFS_ALL_COMPR_ALGS ((1 << Z_EROFS_COMPRESSION_MAX) - 1) + +/* 14 bytes (+ length field = 16 bytes) */ +struct z_erofs_lz4_cfgs { + __le16 max_distance; + __le16 max_pclusterblks; + u8 reserved[10]; +} __packed; + +/* 14 bytes (+ length field = 16 bytes) */ +struct z_erofs_lzma_cfgs { + __le32 dict_size; + __le16 format; + u8 reserved[8]; +} __packed; + +#define Z_EROFS_LZMA_MAX_DICT_SIZE (8 * Z_EROFS_PCLUSTER_MAX_SIZE) + +/* 6 bytes (+ length field = 8 bytes) */ +struct z_erofs_deflate_cfgs { + u8 windowbits; /* 8..15 for DEFLATE */ + u8 reserved[5]; +} __packed; + +/* 6 bytes (+ length field = 8 bytes) */ +struct z_erofs_zstd_cfgs { + u8 format; + u8 windowlog; /* windowLog - ZSTD_WINDOWLOG_ABSOLUTEMIN(10) */ + u8 reserved[4]; +} __packed; + +#define Z_EROFS_ZSTD_MAX_DICT_SIZE Z_EROFS_PCLUSTER_MAX_SIZE + +/* + * Enable COMPACTED_2B for EROFS_INODE_COMPRESSED_COMPACT inodes: + * 4B (disabled) vs 4B+2B+4B (enabled) + */ +#define Z_EROFS_ADVISE_COMPACTED_2B 0x0001 +/* Enable extent metadata for EROFS_INODE_COMPRESSED_FULL inodes */ +#define Z_EROFS_ADVISE_EXTENTS 0x0001 +#define Z_EROFS_ADVISE_BIG_PCLUSTER_1 0x0002 +#define Z_EROFS_ADVISE_BIG_PCLUSTER_2 0x0004 +#define Z_EROFS_ADVISE_INLINE_PCLUSTER 0x0008 +#define Z_EROFS_ADVISE_INTERLACED_PCLUSTER 0x0010 +#define Z_EROFS_ADVISE_FRAGMENT_PCLUSTER 0x0020 +/* Indicate the record size for each extent if extent metadata is used */ +#define Z_EROFS_ADVISE_EXTRECSZ_BIT 1 +#define Z_EROFS_ADVISE_EXTRECSZ_MASK 0x3 + +#define Z_EROFS_FRAGMENT_INODE_BIT 7 +struct z_erofs_map_header { + union { + /* fragment data offset in the packed inode */ + __le32 h_fragmentoff; + struct { + __le16 h_reserved1; + /* indicates the encoded size of tailpacking data */ + __le16 h_idata_size; + }; + __le32 h_extents_lo; /* extent count LSB */ + }; + __le16 h_advise; + union { + struct { + /* algorithm type (bit 0-3: HEAD1; bit 4-7: HEAD2) */ + __u8 h_algorithmtype; + /* + * bit 0-3 : logical cluster bits - blkszbits + * bit 4-6 : reserved + * bit 7 : pack the whole file into packed inode + */ + __u8 h_clusterbits; + } __packed; + __le16 h_extents_hi; /* extent count MSB */ + } __packed; +}; + +enum { + Z_EROFS_LCLUSTER_TYPE_PLAIN = 0, + Z_EROFS_LCLUSTER_TYPE_HEAD1 = 1, + Z_EROFS_LCLUSTER_TYPE_NONHEAD = 2, + Z_EROFS_LCLUSTER_TYPE_HEAD2 = 3, + Z_EROFS_LCLUSTER_TYPE_MAX +}; + +#define Z_EROFS_LI_LCLUSTER_TYPE_MASK (Z_EROFS_LCLUSTER_TYPE_MAX - 1) + +/* (noncompact only, HEAD) This pcluster refers to partial decompressed data */ +#define Z_EROFS_LI_PARTIAL_REF (1 << 15) + +/* Set on 1st non-head lcluster to store compressed block counti (in blocks) */ +#define Z_EROFS_LI_D0_CBLKCNT (1 << 11) + +struct z_erofs_lcluster_index { + __le16 di_advise; + /* where to decompress in the head lcluster */ + __le16 di_clusterofs; + + union { + __le32 blkaddr; /* for the HEAD lclusters */ + /* + * [0] - distance to its HEAD lcluster + * [1] - distance to the next HEAD lcluster + */ + __le16 delta[2]; /* for the NONHEAD lclusters */ + } di_u; +}; + +#define Z_EROFS_MAP_HEADER_END(end) \ + (ALIGN(end, 8) + sizeof(struct z_erofs_map_header)) +#define Z_EROFS_FULL_INDEX_START(end) (Z_EROFS_MAP_HEADER_END(end) + 8) + +#define Z_EROFS_EXTENT_PLEN_PARTIAL BIT(27) +#define Z_EROFS_EXTENT_PLEN_FMT_BIT 28 +#define Z_EROFS_EXTENT_PLEN_MASK ((Z_EROFS_PCLUSTER_MAX_SIZE << 1) - 1) +struct z_erofs_extent { + __le32 plen; /* encoded length */ + __le32 pstart_lo; /* physical offset */ + __le32 pstart_hi; /* physical offset MSB */ + __le32 lstart_lo; /* logical offset */ + __le32 lstart_hi; /* logical offset MSB (>= 4GiB inodes) */ + __u8 reserved[12]; /* for future use */ +}; + +static inline int z_erofs_extent_recsize(unsigned int advise) +{ + return 4 << ((advise >> Z_EROFS_ADVISE_EXTRECSZ_BIT) & + Z_EROFS_ADVISE_EXTRECSZ_MASK); +} + +/* check the EROFS on-disk layout strictly at compile time */ +static inline void erofs_check_ondisk_layout_definitions(void) +{ + const __le64 fmh = *(__le64 *)&(struct z_erofs_map_header) { + .h_clusterbits = 1 << Z_EROFS_FRAGMENT_INODE_BIT + }; + + BUILD_BUG_ON(sizeof(struct erofs_super_block) != 144); + BUILD_BUG_ON(sizeof(struct erofs_inode_compact) != 32); + BUILD_BUG_ON(sizeof(struct erofs_inode_extended) != 64); + BUILD_BUG_ON(sizeof(struct erofs_xattr_ibody_header) != 12); + BUILD_BUG_ON(sizeof(struct erofs_xattr_entry) != 4); + BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_info) != 4); + BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_index) != 8); + BUILD_BUG_ON(sizeof(struct z_erofs_map_header) != 8); + BUILD_BUG_ON(sizeof(struct z_erofs_lcluster_index) != 8); + BUILD_BUG_ON(sizeof(struct erofs_dirent) != 12); + /* keep in sync between 2 index structures for better extendibility */ + BUILD_BUG_ON(sizeof(struct erofs_inode_chunk_index) != + sizeof(struct z_erofs_lcluster_index)); + BUILD_BUG_ON(sizeof(struct erofs_deviceslot) != 128); + + /* exclude old compiler versions like gcc 7.5.0 */ + BUILD_BUG_ON(__builtin_constant_p(fmh) ? + fmh != cpu_to_le64(1ULL << 63) : 0); +} + +#endif |