[PATCH v4 2/2] erofs: set block size to the on-disk block size

[Gao Xiang]

On 2023/3/2 22:39, Jingbo Xu wrote:
> Set the block size to that specified in on-disk superblock.
> 
> Also remove the hard constraint of PAGE_SIZE block size for the
> uncompressed device backend.  This constraint is temporarily remained
> for compressed device and fscache backend, as there is more work needed
> to handle the condition where the block size is not equal to PAGE_SIZE.
> 
> It is worth noting that the on-disk block size is read prior to
> erofs_superblock_csum_verify(), as the read block size is needed in the
> latter.
> 
> Besides, later we are going to make erofs refer to tar data blobs (which
> is 512-byte aligned) for OCI containers, where the block size is 512
> bytes.  In this case, the 512-byte block size may not be adequate for a
> directory to contain enough dirents.  To fix this, we are also going to
> introduce directory block size independent on the block size.
> 
> Due to we have already supported block size smaller than PAGE_SIZE now,
> disable all these images with such separated directory block size until
> we supported this feature later.
> 
> Signed-off-by: Jingbo Xu <jefflexu at linux.alibaba.com>

Reviewed-by: Gao Xiang <hsiangkao at linux.alibaba.com>

Thanks,
Gao Xiang