1/ When resyncing a degraded raid10 which has more than 2 copies of each block,
garbage can get synced on top of good data.
2/ We round the wrong way in part of the device size calculation, which
can cause confusion.
Signed-off-by: Neil Brown <neilb@suse.de> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>