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| author | Gao Xiang <hsiangkao@linux.alibaba.com> | 2021-10-11 00:31:45 +0300 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2021-10-19 18:44:30 +0300 |
| commit | 622ceaddb7649ca328832f50ba1400af778d75fa (patch) | |
| tree | 6e6a3db1cff711620944b9e283c2bd5f4dbd6171 /fs/erofs/erofs_fs.h | |
| parent | 966edfb0a3dc2adf5aab461c298fa0feb02f49d6 (diff) | |
| download | linux-622ceaddb7649ca328832f50ba1400af778d75fa.tar.xz | |
erofs: lzma compression support
Add MicroLZMA support in order to maximize compression ratios for
specific scenarios. For example, it's useful for low-end embedded
boards and as a secondary algorithm in a file for specific access
patterns.
MicroLZMA is a new container format for raw LZMA1, which was created
by Lasse Collin aiming to minimize old LZMA headers and get rid of
unnecessary EOPM (end of payload marker) as well as to enable
fixed-sized output compression, especially for 4KiB pclusters.
Similar to LZ4, inplace I/O approach is used to minimize runtime
memory footprint when dealing with I/O. Overlapped decompression is
handled with 1) bounced buffer for data under processing or 2) extra
short-lived pages from the on-stack pagepool which will be shared in
the same read request (128KiB for example).
Link: https://lore.kernel.org/r/20211010213145.17462-8-xiang@kernel.org
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs/erofs/erofs_fs.h')
| -rw-r--r-- | fs/erofs/erofs_fs.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h index 1c2917181346..083997a034e5 100644 --- a/fs/erofs/erofs_fs.h +++ b/fs/erofs/erofs_fs.h @@ -264,10 +264,11 @@ struct erofs_inode_chunk_index { /* available compression algorithm types (for h_algorithmtype) */ enum { - Z_EROFS_COMPRESSION_LZ4 = 0, + 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)) +#define Z_EROFS_ALL_COMPR_ALGS ((1 << Z_EROFS_COMPRESSION_MAX) - 1) /* 14 bytes (+ length field = 16 bytes) */ struct z_erofs_lz4_cfgs { @@ -276,6 +277,15 @@ struct z_erofs_lz4_cfgs { 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; |