Skip to content

Commit

Permalink
erofs: tidy up EROFS on-disk naming
Browse files Browse the repository at this point in the history 
 - Get rid of all "vle" (variable-length extents) expressions
   since they only expand overall name lengths unnecessarily;
 - Rename COMPRESSION_LEGACY to COMPRESSED_FULL;
 - Move on-disk directory definitions ahead of compression;
 - Drop unused extended attribute definitions;
 - Move inode ondisk union `i_u` out as `union erofs_inode_i_u`.

No actual logical change.

Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20230331063149.25611-1-hsiangkao@linux.alibaba.com
  • Loading branch information
Gao Xiang committed Apr 16, 2023
1 parent 8b465fe commit 1c7f49a
Show file tree
Hide file tree
Showing 2 changed files with 119 additions and 142 deletions.
145 changes: 62 additions & 83 deletions fs/erofs/erofs_fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -82,32 +82,27 @@ struct erofs_super_block {
};

/*
* erofs inode datalayout (i_format in on-disk inode):
* EROFS inode datalayout (i_format in on-disk inode):
* 0 - uncompressed flat inode without tail-packing inline data:
* inode, [xattrs], ... | ... | no-holed data
* 1 - compressed inode with non-compact indexes:
* inode, [xattrs], [map_header], extents ... | ...
* 2 - uncompressed flat inode with tail-packing inline data:
* inode, [xattrs], tailpacking data, ... | ... | no-holed data
* 3 - compressed inode with compact indexes:
* inode, [xattrs], map_header, extents ... | ...
* 4 - chunk-based inode with (optional) multi-device support:
* inode, [xattrs], chunk indexes ... | ...
* 5~7 - reserved
*/
enum {
EROFS_INODE_FLAT_PLAIN = 0,
EROFS_INODE_FLAT_COMPRESSION_LEGACY = 1,
EROFS_INODE_COMPRESSED_FULL = 1,
EROFS_INODE_FLAT_INLINE = 2,
EROFS_INODE_FLAT_COMPRESSION = 3,
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_FLAT_COMPRESSION ||
datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
return datamode == EROFS_INODE_COMPRESSED_COMPACT ||
datamode == EROFS_INODE_COMPRESSED_FULL;
}

/* bit definitions of inode i_format */
Expand All @@ -128,11 +123,30 @@ static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
#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 */
Expand All @@ -143,29 +157,14 @@ struct erofs_inode_compact {
__le16 i_nlink;
__le32 i_size;
__le32 i_reserved;
union {
/* 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;
} i_u;
__le32 i_ino; /* only used for 32-bit stat compatibility */
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;
};

/* 32-byte on-disk inode */
#define EROFS_INODE_LAYOUT_COMPACT 0
/* 64-byte 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 */
Expand All @@ -175,22 +174,9 @@ struct erofs_inode_extended {
__le16 i_mode;
__le16 i_reserved;
__le64 i_size;
union {
/* 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;
} i_u;

/* only used for 32-bit stat compatibility */
__le32 i_ino;
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;
Expand All @@ -199,10 +185,6 @@ struct erofs_inode_extended {
__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
Expand Down Expand Up @@ -268,6 +250,22 @@ struct erofs_inode_chunk_index {
__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)

Expand Down Expand Up @@ -337,10 +335,8 @@ struct z_erofs_map_header {
__u8 h_clusterbits;
};

#define Z_EROFS_VLE_LEGACY_HEADER_PADDING 8

/*
* Fixed-sized output compression on-disk logical cluster type:
* On-disk logical cluster type:
* 0 - literal (uncompressed) lcluster
* 1,3 - compressed lcluster (for HEAD lclusters)
* 2 - compressed lcluster (for NONHEAD lclusters)
Expand All @@ -364,27 +360,27 @@ struct z_erofs_map_header {
* di_u.delta[1] = distance to the next HEAD lcluster
*/
enum {
Z_EROFS_VLE_CLUSTER_TYPE_PLAIN = 0,
Z_EROFS_VLE_CLUSTER_TYPE_HEAD1 = 1,
Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD = 2,
Z_EROFS_VLE_CLUSTER_TYPE_HEAD2 = 3,
Z_EROFS_VLE_CLUSTER_TYPE_MAX
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_VLE_DI_CLUSTER_TYPE_BITS 2
#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT 0
#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_VLE_DI_PARTIAL_REF (1 << 15)
#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_VLE_DI_D0_CBLKCNT (1 << 11)
#define Z_EROFS_LI_D0_CBLKCNT (1 << 11)

struct z_erofs_vle_decompressed_index {
struct z_erofs_lcluster_index {
__le16 di_advise;
/* where to decompress in the head lcluster */
__le16 di_clusterofs;
Expand All @@ -401,25 +397,8 @@ struct z_erofs_vle_decompressed_index {
} 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
#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)
Expand All @@ -436,15 +415,15 @@ static inline void erofs_check_ondisk_layout_definitions(void)
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_vle_decompressed_index) != 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_vle_decompressed_index));
sizeof(struct z_erofs_lcluster_index));
BUILD_BUG_ON(sizeof(struct erofs_deviceslot) != 128);

BUILD_BUG_ON(BIT(Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) <
Z_EROFS_VLE_CLUSTER_TYPE_MAX - 1);
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);
Expand Down
Loading

0 comments on commit 1c7f49a

Please sign in to comment.