When doing recovery on a raid10 with a write-intent bitmap, we only
need to recovery chunks that are flagged in the bitmap.
However if we choose to skip a chunk as it isn't flag, the code
currently skips the whole raid10-chunk, thus it might not recovery
some blocks that need recovering.
This patch fixes it.
In case that is confusing, it might help to understand that there
is a 'raid10 chunk size' which guides how data is distributed across
the devices, and a 'bitmap chunk size' which says how much data
corresponds to a single bit in the bitmap.
This bug only affects cases where the bitmap chunk size is smaller
than the raid10 chunk size.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
09b4068a7f