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>
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