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authorGao Xiang <hsiangkao@linux.alibaba.com>2021-08-20 18:00:18 +0800
committerGao Xiang <hsiangkao@linux.alibaba.com>2021-08-20 22:38:01 +0800
commit2a9dc7a8fec6ca287e2c038f9441e24269e10b5f (patch)
tree69cc5664ddef0dd151f1c9fb3d573cb36640a42b /fs/erofs
parenteadcd6b5a1eb39866ab8d8a3e4f2e51bc51a2350 (diff)
erofs: introduce chunk-based file on-disk format
Currently, uncompressed data except for tail-packing inline is consecutive on disk. In order to support chunk-based data deduplication, add a new corresponding inode data layout. In the future, the data source of chunks can be either (un)compressed. Link: https://lore.kernel.org/r/20210820100019.208490-1-hsiangkao@linux.alibaba.com Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com> Reviewed-by: Chao Yu <chao@kernel.org> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs')
-rw-r--r--fs/erofs/erofs_fs.h47
1 files changed, 45 insertions, 2 deletions
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 0f8da74570b4..b0b23f41abc3 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -4,6 +4,7 @@
*
* Copyright (C) 2017-2018 HUAWEI, Inc.
* https://www.huawei.com/
+ * Copyright (C) 2021, Alibaba Cloud
*/
#ifndef __EROFS_FS_H
#define __EROFS_FS_H
@@ -19,10 +20,12 @@
#define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING 0x00000001
#define EROFS_FEATURE_INCOMPAT_COMPR_CFGS 0x00000002
#define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER 0x00000002
+#define EROFS_FEATURE_INCOMPAT_CHUNKED_FILE 0x00000004
#define EROFS_ALL_FEATURE_INCOMPAT \
(EROFS_FEATURE_INCOMPAT_LZ4_0PADDING | \
EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \
- EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER)
+ EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER | \
+ EROFS_FEATURE_INCOMPAT_CHUNKED_FILE)
#define EROFS_SB_EXTSLOT_SIZE 16
@@ -64,13 +67,16 @@ struct erofs_super_block {
* inode, [xattrs], last_inline_data, ... | ... | no-holed data
* 3 - inode compression D:
* inode, [xattrs], map_header, extents ... | ...
- * 4~7 - reserved
+ * 4 - inode chunk-based E:
+ * inode, [xattrs], chunk indexes ... | ...
+ * 5~7 - 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_CHUNK_BASED = 4,
EROFS_INODE_DATALAYOUT_MAX
};
@@ -90,6 +96,19 @@ static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
#define EROFS_I_ALL \
((1 << (EROFS_I_DATALAYOUT_BIT + EROFS_I_DATALAYOUT_BITS)) - 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)
+
+struct erofs_inode_chunk_info {
+ __le16 format; /* chunk blkbits, etc. */
+ __le16 reserved;
+};
+
/* 32-byte reduced form of an ondisk inode */
struct erofs_inode_compact {
__le16 i_format; /* inode format hints */
@@ -107,6 +126,9 @@ struct erofs_inode_compact {
/* 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 */
__le16 i_uid;
@@ -135,6 +157,9 @@ struct erofs_inode_extended {
/* 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 */
@@ -204,6 +229,19 @@ static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e)
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, always 0 for now */
+ __le32 blkaddr; /* start block address of this inode chunk */
+};
+
/* maximum supported size of a physical compression cluster */
#define Z_EROFS_PCLUSTER_MAX_SIZE (1024 * 1024)
@@ -338,9 +376,14 @@ static inline void erofs_check_ondisk_layout_definitions(void)
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_vle_decompressed_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));
BUILD_BUG_ON(BIT(Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) <
Z_EROFS_VLE_CLUSTER_TYPE_MAX - 1);