| /* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */ |
| /* |
| * EROFS (Enhanced ROM File System) on-disk format definition |
| * |
| * Copyright (C) 2017-2018 HUAWEI, Inc. |
| * https://www.huawei.com/ |
| */ |
| #ifndef __EROFS_FS_H |
| #define __EROFS_FS_H |
| |
| #define EROFS_SUPER_OFFSET 1024 |
| |
| #define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001 |
| |
| /* |
| * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should |
| * be incompatible with this kernel version. |
| */ |
| #define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING 0x00000001 |
| #define EROFS_FEATURE_INCOMPAT_COMPR_CFGS 0x00000002 |
| #define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER 0x00000002 |
| #define EROFS_ALL_FEATURE_INCOMPAT \ |
| (EROFS_FEATURE_INCOMPAT_LZ4_0PADDING | \ |
| EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \ |
| EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER) |
| |
| #define EROFS_SB_EXTSLOT_SIZE 16 |
| |
| /* erofs on-disk super block (currently 128 bytes) */ |
| struct erofs_super_block { |
| __le32 magic; /* file system magic number */ |
| __le32 checksum; /* crc32c(super_block) */ |
| __le32 feature_compat; |
| __u8 blkszbits; /* support block_size == PAGE_SIZE only */ |
| __u8 sb_extslots; /* superblock size = 128 + sb_extslots * 16 */ |
| |
| __le16 root_nid; /* nid of root directory */ |
| __le64 inos; /* total valid ino # (== f_files - f_favail) */ |
| |
| __le64 build_time; /* inode v1 time derivation */ |
| __le32 build_time_nsec; /* inode v1 time derivation in nano scale */ |
| __le32 blocks; /* used for statfs */ |
| __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; |
| __u8 reserved2[42]; |
| }; |
| |
| /* |
| * erofs inode datalayout (i_format in on-disk inode): |
| * 0 - inode plain without inline data A: |
| * inode, [xattrs], ... | ... | no-holed data |
| * 1 - inode VLE compression B (legacy): |
| * inode, [xattrs], extents ... | ... |
| * 2 - inode plain with inline data C: |
| * inode, [xattrs], last_inline_data, ... | ... | no-holed data |
| * 3 - inode compression D: |
| * inode, [xattrs], map_header, extents ... | ... |
| * 4~7 - reserved |
| */ |
| enum { |
| EROFS_INODE_FLAT_PLAIN = 0, |
| EROFS_INODE_FLAT_COMPRESSION_LEGACY = 1, |
| EROFS_INODE_FLAT_INLINE = 2, |
| EROFS_INODE_FLAT_COMPRESSION = 3, |
| EROFS_INODE_DATALAYOUT_MAX |
| }; |
| |
| static inline bool erofs_inode_is_data_compressed(unsigned int datamode) |
| { |
| return datamode == EROFS_INODE_FLAT_COMPRESSION || |
| datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY; |
| } |
| |
| /* bit definitions of inode i_advise */ |
| #define EROFS_I_VERSION_BITS 1 |
| #define EROFS_I_DATALAYOUT_BITS 3 |
| |
| #define EROFS_I_VERSION_BIT 0 |
| #define EROFS_I_DATALAYOUT_BIT 1 |
| |
| #define EROFS_I_ALL \ |
| ((1 << (EROFS_I_DATALAYOUT_BIT + EROFS_I_DATALAYOUT_BITS)) - 1) |
| |
| /* 32-byte reduced form of an ondisk inode */ |
| struct erofs_inode_compact { |
| __le16 i_format; /* inode format hints */ |
| |
| /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */ |
| __le16 i_xattr_icount; |
| __le16 i_mode; |
| __le16 i_nlink; |
| __le32 i_size; |
| __le32 i_reserved; |
| union { |
| /* file total compressed blocks for data mapping 1 */ |
| __le32 compressed_blocks; |
| __le32 raw_blkaddr; |
| |
| /* for device files, used to indicate old/new device # */ |
| __le32 rdev; |
| } i_u; |
| __le32 i_ino; /* only used for 32-bit stat compatibility */ |
| __le16 i_uid; |
| __le16 i_gid; |
| __le32 i_reserved2; |
| }; |
| |
| /* 32 bytes on-disk inode */ |
| #define EROFS_INODE_LAYOUT_COMPACT 0 |
| /* 64 bytes on-disk inode */ |
| #define EROFS_INODE_LAYOUT_EXTENDED 1 |
| |
| /* 64-byte complete form of an ondisk inode */ |
| struct erofs_inode_extended { |
| __le16 i_format; /* inode format hints */ |
| |
| /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */ |
| __le16 i_xattr_icount; |
| __le16 i_mode; |
| __le16 i_reserved; |
| __le64 i_size; |
| union { |
| /* file total compressed blocks for data mapping 1 */ |
| __le32 compressed_blocks; |
| __le32 raw_blkaddr; |
| |
| /* for device files, used to indicate old/new device # */ |
| __le32 rdev; |
| } i_u; |
| |
| /* only used for 32-bit stat compatibility */ |
| __le32 i_ino; |
| |
| __le32 i_uid; |
| __le32 i_gid; |
| __le64 i_ctime; |
| __le32 i_ctime_nsec; |
| __le32 i_nlink; |
| __u8 i_reserved2[16]; |
| }; |
| |
| #define EROFS_MAX_SHARED_XATTRS (128) |
| /* h_shared_count between 129 ... 255 are special # */ |
| #define EROFS_SHARED_XATTR_EXTENT (255) |
| |
| /* |
| * 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_reserved; |
| __u8 h_shared_count; |
| __u8 h_reserved2[7]; |
| __le32 h_shared_xattrs[0]; /* 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 |
| |
| /* 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[0]; /* attribute name */ |
| }; |
| |
| static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount) |
| { |
| if (!i_xattr_icount) |
| return 0; |
| |
| 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)); |
| } |
| |
| /* maximum supported size of a physical compression cluster */ |
| #define Z_EROFS_PCLUSTER_MAX_SIZE (1024 * 1024) |
| |
| /* available compression algorithm types (for h_algorithmtype) */ |
| enum { |
| Z_EROFS_COMPRESSION_LZ4 = 0, |
| 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; |
| |
| /* |
| * bit 0 : COMPACTED_2B indexes (0 - off; 1 - on) |
| * e.g. for 4k logical cluster size, 4B if compacted 2B is off; |
| * (4B) + 2B + (4B) if compacted 2B is on. |
| * bit 1 : HEAD1 big pcluster (0 - off; 1 - on) |
| * bit 2 : HEAD2 big pcluster (0 - off; 1 - on) |
| */ |
| #define Z_EROFS_ADVISE_COMPACTED_2B 0x0001 |
| #define Z_EROFS_ADVISE_BIG_PCLUSTER_1 0x0002 |
| #define Z_EROFS_ADVISE_BIG_PCLUSTER_2 0x0004 |
| |
| struct z_erofs_map_header { |
| __le32 h_reserved1; |
| __le16 h_advise; |
| /* |
| * bit 0-3 : algorithm type of head 1 (logical cluster type 01); |
| * bit 4-7 : algorithm type of head 2 (logical cluster type 11). |
| */ |
| __u8 h_algorithmtype; |
| /* |
| * bit 0-2 : logical cluster bits - 12, e.g. 0 for 4096; |
| * bit 3-7 : reserved. |
| */ |
| __u8 h_clusterbits; |
| }; |
| |
| #define Z_EROFS_VLE_LEGACY_HEADER_PADDING 8 |
| |
| /* |
| * Fixed-sized output compression ondisk Logical Extent cluster type: |
| * 0 - literal (uncompressed) cluster |
| * 1 - compressed cluster (for the head logical cluster) |
| * 2 - compressed cluster (for the other logical clusters) |
| * |
| * In detail, |
| * 0 - literal (uncompressed) cluster, |
| * di_advise = 0 |
| * di_clusterofs = the literal data offset of the cluster |
| * di_blkaddr = the blkaddr of the literal cluster |
| * |
| * 1 - compressed cluster (for the head logical cluster) |
| * di_advise = 1 |
| * di_clusterofs = the decompressed data offset of the cluster |
| * di_blkaddr = the blkaddr of the compressed cluster |
| * |
| * 2 - compressed cluster (for the other logical clusters) |
| * di_advise = 2 |
| * di_clusterofs = |
| * the decompressed data offset in its own head cluster |
| * di_u.delta[0] = distance to its corresponding head cluster |
| * di_u.delta[1] = distance to its corresponding tail cluster |
| * (di_advise could be 0, 1 or 2) |
| */ |
| enum { |
| Z_EROFS_VLE_CLUSTER_TYPE_PLAIN = 0, |
| Z_EROFS_VLE_CLUSTER_TYPE_HEAD = 1, |
| Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD = 2, |
| Z_EROFS_VLE_CLUSTER_TYPE_RESERVED = 3, |
| Z_EROFS_VLE_CLUSTER_TYPE_MAX |
| }; |
| |
| #define Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS 2 |
| #define Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT 0 |
| |
| /* |
| * D0_CBLKCNT will be marked _only_ at the 1st non-head lcluster to store the |
| * compressed block count of a compressed extent (in logical clusters, aka. |
| * block count of a pcluster). |
| */ |
| #define Z_EROFS_VLE_DI_D0_CBLKCNT (1 << 11) |
| |
| struct z_erofs_vle_decompressed_index { |
| __le16 di_advise; |
| /* where to decompress in the head cluster */ |
| __le16 di_clusterofs; |
| |
| union { |
| /* for the head cluster */ |
| __le32 blkaddr; |
| /* |
| * for the rest clusters |
| * eg. for 4k page-sized cluster, maximum 4K*64k = 256M) |
| * [0] - pointing to the head cluster |
| * [1] - pointing to the tail cluster |
| */ |
| __le16 delta[2]; |
| } di_u; |
| }; |
| |
| #define Z_EROFS_VLE_LEGACY_INDEX_ALIGN(size) \ |
| (round_up(size, sizeof(struct z_erofs_vle_decompressed_index)) + \ |
| sizeof(struct z_erofs_map_header) + Z_EROFS_VLE_LEGACY_HEADER_PADDING) |
| |
| /* 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 |
| |
| /* check the EROFS on-disk layout strictly at compile time */ |
| static inline void erofs_check_ondisk_layout_definitions(void) |
| { |
| BUILD_BUG_ON(sizeof(struct erofs_super_block) != 128); |
| 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 z_erofs_map_header) != 8); |
| BUILD_BUG_ON(sizeof(struct z_erofs_vle_decompressed_index) != 8); |
| BUILD_BUG_ON(sizeof(struct erofs_dirent) != 12); |
| |
| BUILD_BUG_ON(BIT(Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) < |
| Z_EROFS_VLE_CLUSTER_TYPE_MAX - 1); |
| } |
| |
| #endif |