[PATCH 2/2] erofs: get correct count for unmapped range in fscache mode

[Chao Yu]

On 2022/11/4 13:40, Jingbo Xu wrote:
> For unmapped range, the returned map.m_llen is zero, and thus the
> calculated count is unexpected zero.
> 
> Prior to the refactoring introduced by commit 1ae9470c3e14 ("erofs:
> clean up .read_folio() and .readahead() in fscache mode"), only the
> readahead routine suffers from this. With the refactoring of making
> .read_folio() and .readahead() calling one common routine, both
> read_folio and readahead have this issue now.
> 
> Fix this by calculating count separately in unmapped condition.
> 
> Fixes: c665b394b9e8 ("erofs: implement fscache-based data readahead")
> Fixes: 1ae9470c3e14 ("erofs: clean up .read_folio() and .readahead() in fscache mode")
> Signed-off-by: Jingbo Xu <jefflexu at linux.alibaba.com>

Reviewed-by: Chao Yu <chao at kernel.org>

Thanks,