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| author | Yue Hu <huyue2@coolpad.com> | 2022-09-23 04:11:21 +0200 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2022-09-23 04:55:56 +0200 |
| commit | fdffc091e6f94602558bba712b51bc16f79fd6d5 (patch) | |
| tree | d6daa04f5f2e867786577dca54fd0ef194145fa5 /fs/erofs/erofs_fs.h | |
| parent | erofs: clean up .read_folio() and .readahead() in fscache mode (diff) | |
| download | linux-fdffc091e6f94602558bba712b51bc16f79fd6d5.tar.xz linux-fdffc091e6f94602558bba712b51bc16f79fd6d5.zip | |
erofs: support interlaced uncompressed data for compressed files
Currently, uncompressed data is all handled in the shifted way, which
means we have to shift the whole on-disk plain pcluster to get the
logical data. However, since we are also using in-place I/O for
uncompressed data, data copy will be reduced a lot if pcluster is
recorded in the interlaced way as illustrated below:
_______________________________________________________________
| | | |_ tail part |_ head part _|
|<- blk0 ->| .. |<- blkn-2 ->|<- blkn-1 ->|
The logical data then becomes:
________________________________________________________
|_ head part _|_ blk0 _| .. |_ blkn-2 _|_ tail part _|
In addition, non-4k plain pclusters are also survived by the
interlaced way, which can be used for non-4k lclusters as well.
However, it's almost impossible to de-duplicate uncompressed data
in the interlaced way, therefore shifted uncompressed data is still
useful.
Signed-off-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/8369112678604fdf4ef796626d59b1fdd0745a53.1663898962.git.huyue2@coolpad.com
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 | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h index 2b48373f690b..5c1de6d7ad71 100644 --- a/fs/erofs/erofs_fs.h +++ b/fs/erofs/erofs_fs.h @@ -295,11 +295,13 @@ struct z_erofs_lzma_cfgs { * 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) */ #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 struct z_erofs_map_header { __le16 h_reserved1; |