OpenCloudOS-Kernel/fs/erofs/erofs_fs.h

449 lines
14 KiB
C
Raw Normal View History

/* 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/
* Copyright (C) 2021, Alibaba Cloud
*/
#ifndef __EROFS_FS_H
#define __EROFS_FS_H
#define EROFS_SUPER_OFFSET 1024
#define EROFS_FEATURE_COMPAT_SB_CHKSUM 0x00000001
#define EROFS_FEATURE_COMPAT_MTIME 0x00000002
/*
* 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_ALL_FEATURE_INCOMPAT \
(EROFS_FEATURE_INCOMPAT_ZERO_PADDING | \
EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \
EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER | \
EROFS_FEATURE_INCOMPAT_CHUNKED_FILE | \
EROFS_FEATURE_INCOMPAT_DEVICE_TABLE | \
EROFS_FEATURE_INCOMPAT_COMPR_HEAD2 | \
EROFS_FEATURE_INCOMPAT_ZTAILPACKING | \
EROFS_FEATURE_INCOMPAT_FRAGMENTS | \
EROFS_FEATURE_INCOMPAT_DEDUPE | \
EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES)
#define EROFS_SB_EXTSLOT_SIZE 16
struct erofs_deviceslot {
u8 tag[64]; /* digest(sha256), etc. */
__le32 blocks; /* total fs blocks of this device */
__le32 mapped_blkaddr; /* map starting at mapped_blkaddr */
u8 reserved[56];
};
#define EROFS_DEVT_SLOT_SIZE sizeof(struct erofs_deviceslot)
/* 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; /* filesystem block size in bit shift */
__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; /* compact inode time derivation */
__le32 build_time_nsec; /* compact inode time derivation in ns 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;
__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 */
erofs: introduce on-disk format for long xattr name prefixes Besides the predefined xattr name prefixes, introduces long xattr name prefixes, which work similarly as the predefined name prefixes, except that they are user specified. It is especially useful for use cases together with overlayfs like Composefs model, which introduces diverse xattr values with only a few common xattr names (trusted.overlay.redirect, trusted.overlay.digest, and maybe more in the future). That makes the existing predefined prefixes ineffective in both image size and runtime performance. When a user specified long xattr name prefix is used, only the trailing part of the xattr name apart from the long xattr name prefix will be stored in erofs_xattr_entry.e_name. e_name is empty if the xattr name matches exactly as the long xattr name prefix. All long xattr prefixes are stored in the packed or meta inode, which depends if fragments feature is enabled or not. For each long xattr name prefix, the on-disk format is kept as the same as the unique metadata format: ALIGN({__le16 len, data}, 4), where len represents the total size of struct erofs_xattr_long_prefix, followed by data of struct erofs_xattr_long_prefix itself. Each erofs_xattr_long_prefix keeps predefined prefixes (base_index) and the remaining prefix string without the trailing '\0'. Two fields are introduced to the on-disk superblock, where xattr_prefix_count represents the total number of the long xattr name prefixes recorded, and xattr_prefix_start represents the start offset of recorded name prefixes in the packed/meta inode divided by 4. When referring to a long xattr name prefix, the highest bit (bit 7) of erofs_xattr_entry.e_name_index is set, while the lower bits (bit 0-6) as a whole represents the index of the referred long name prefix among all long xattr name prefixes. Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Acked-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20230407141710.113882-5-jefflexu@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2023-04-07 22:17:07 +08:00
__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 reserved2[24];
};
/*
* 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_ALL_BIT 4
#define EROFS_I_ALL ((1 << EROFS_I_ALL_BIT) - 1)
/* indicate chunk blkbits, thus 'chunksize = blocksize << chunk blkbits' */
#define EROFS_CHUNK_FORMAT_BLKBITS_MASK 0x001F
/* with chunk indexes or just a 4-byte blkaddr array */
#define EROFS_CHUNK_FORMAT_INDEXES 0x0020
#define EROFS_CHUNK_FORMAT_ALL \
(EROFS_CHUNK_FORMAT_BLKBITS_MASK | EROFS_CHUNK_FORMAT_INDEXES)
/* 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 {
/* total compressed blocks for compressed inodes */
__le32 compressed_blocks;
/* block address for uncompressed flat inodes */
__le32 raw_blkaddr;
/* for device files, used to indicate old/new device # */
__le32 rdev;
/* for chunk-based files, it contains the summary info */
struct erofs_inode_chunk_info c;
};
/* 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 erofs_inode_i_u i_u;
__le32 i_ino; /* only used for 32-bit stat compatibility */
__le16 i_uid;
__le16 i_gid;
__le32 i_reserved2;
};
/* 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 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_reserved;
__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
erofs: introduce on-disk format for long xattr name prefixes Besides the predefined xattr name prefixes, introduces long xattr name prefixes, which work similarly as the predefined name prefixes, except that they are user specified. It is especially useful for use cases together with overlayfs like Composefs model, which introduces diverse xattr values with only a few common xattr names (trusted.overlay.redirect, trusted.overlay.digest, and maybe more in the future). That makes the existing predefined prefixes ineffective in both image size and runtime performance. When a user specified long xattr name prefix is used, only the trailing part of the xattr name apart from the long xattr name prefix will be stored in erofs_xattr_entry.e_name. e_name is empty if the xattr name matches exactly as the long xattr name prefix. All long xattr prefixes are stored in the packed or meta inode, which depends if fragments feature is enabled or not. For each long xattr name prefix, the on-disk format is kept as the same as the unique metadata format: ALIGN({__le16 len, data}, 4), where len represents the total size of struct erofs_xattr_long_prefix, followed by data of struct erofs_xattr_long_prefix itself. Each erofs_xattr_long_prefix keeps predefined prefixes (base_index) and the remaining prefix string without the trailing '\0'. Two fields are introduced to the on-disk superblock, where xattr_prefix_count represents the total number of the long xattr name prefixes recorded, and xattr_prefix_start represents the start offset of recorded name prefixes in the packed/meta inode divided by 4. When referring to a long xattr name prefix, the highest bit (bit 7) of erofs_xattr_entry.e_name_index is set, while the lower bits (bit 0-6) as a whole represents the index of the referred long name prefix among all long xattr name prefixes. Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Acked-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20230407141710.113882-5-jefflexu@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2023-04-07 22:17:07 +08:00
/*
* 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
/* 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 */
};
erofs: introduce on-disk format for long xattr name prefixes Besides the predefined xattr name prefixes, introduces long xattr name prefixes, which work similarly as the predefined name prefixes, except that they are user specified. It is especially useful for use cases together with overlayfs like Composefs model, which introduces diverse xattr values with only a few common xattr names (trusted.overlay.redirect, trusted.overlay.digest, and maybe more in the future). That makes the existing predefined prefixes ineffective in both image size and runtime performance. When a user specified long xattr name prefix is used, only the trailing part of the xattr name apart from the long xattr name prefix will be stored in erofs_xattr_entry.e_name. e_name is empty if the xattr name matches exactly as the long xattr name prefix. All long xattr prefixes are stored in the packed or meta inode, which depends if fragments feature is enabled or not. For each long xattr name prefix, the on-disk format is kept as the same as the unique metadata format: ALIGN({__le16 len, data}, 4), where len represents the total size of struct erofs_xattr_long_prefix, followed by data of struct erofs_xattr_long_prefix itself. Each erofs_xattr_long_prefix keeps predefined prefixes (base_index) and the remaining prefix string without the trailing '\0'. Two fields are introduced to the on-disk superblock, where xattr_prefix_count represents the total number of the long xattr name prefixes recorded, and xattr_prefix_start represents the start offset of recorded name prefixes in the packed/meta inode divided by 4. When referring to a long xattr name prefix, the highest bit (bit 7) of erofs_xattr_entry.e_name_index is set, while the lower bits (bit 0-6) as a whole represents the index of the referred long name prefix among all long xattr name prefixes. Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com> Acked-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20230407141710.113882-5-jefflexu@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2023-04-07 22:17:07 +08:00
/* 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;
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 indexes */
struct erofs_inode_chunk_index {
__le16 advise; /* always 0, don't care for now */
__le16 device_id; /* back-end storage id (with bits masked) */
__le32 blkaddr; /* start block address of this inode chunk */
};
/* 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 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_LZMA = 1,
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)
/*
* 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)
* bit 3 : tailpacking inline pcluster (0 - off; 1 - on)
* bit 4 : interlaced plain pcluster (0 - off; 1 - on)
* bit 5 : fragment 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
#define Z_EROFS_ADVISE_INLINE_PCLUSTER 0x0008
#define Z_EROFS_ADVISE_INTERLACED_PCLUSTER 0x0010
#define Z_EROFS_ADVISE_FRAGMENT_PCLUSTER 0x0020
#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;
};
};
__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 3-6 : reserved;
* bit 7 : move the whole file into packed inode or not.
*/
__u8 h_clusterbits;
};
/*
* On-disk logical cluster type:
* 0 - literal (uncompressed) lcluster
* 1,3 - compressed lcluster (for HEAD lclusters)
* 2 - compressed lcluster (for NONHEAD lclusters)
*
* In detail,
* 0 - literal (uncompressed) lcluster,
* di_advise = 0
* di_clusterofs = the literal data offset of the lcluster
* di_blkaddr = the blkaddr of the literal pcluster
*
* 1,3 - compressed lcluster (for HEAD lclusters)
* di_advise = 1 or 3
* di_clusterofs = the decompressed data offset of the lcluster
* di_blkaddr = the blkaddr of the compressed pcluster
*
* 2 - compressed lcluster (for NONHEAD lclusters)
* di_advise = 2
* di_clusterofs =
* the decompressed data offset in its own HEAD lcluster
* di_u.delta[0] = distance to this HEAD lcluster
* di_u.delta[1] = distance to the next HEAD lcluster
*/
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_BITS 2
#define Z_EROFS_LI_LCLUSTER_TYPE_BIT 0
/* (noncompact only, HEAD) This pcluster refers to partial decompressed data */
#define Z_EROFS_LI_PARTIAL_REF (1 << 15)
/*
* 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_LI_D0_CBLKCNT (1 << 11)
struct z_erofs_lcluster_index {
__le16 di_advise;
/* where to decompress in the head lcluster */
__le16 di_clusterofs;
union {
/* for the HEAD lclusters */
__le32 blkaddr;
/*
* for the NONHEAD lclusters
* [0] - distance to its HEAD lcluster
* [1] - distance to the next HEAD lcluster
*/
__le16 delta[2];
} di_u;
};
#define Z_EROFS_FULL_INDEX_ALIGN(end) \
(ALIGN(end, 8) + sizeof(struct z_erofs_map_header) + 8)
/* 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) != 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 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);
BUILD_BUG_ON(BIT(Z_EROFS_LI_LCLUSTER_TYPE_BITS) <
Z_EROFS_LCLUSTER_TYPE_MAX - 1);
/* exclude old compiler versions like gcc 7.5.0 */
BUILD_BUG_ON(__builtin_constant_p(fmh) ?
fmh != cpu_to_le64(1ULL << 63) : 0);
}
#endif