md/raid1: fix counting of write targets.
commit574f89ba4649de169c49028f8fc01681a51bf459
authorNeilBrown <neilb@suse.de>
Tue, 18 May 2010 05:27:13 +0000 (18 15:27 +1000)
committerGreg Kroah-Hartman <gregkh@suse.de>
Mon, 5 Jul 2010 18:15:49 +0000 (5 11:15 -0700)
tree26e6ede4b82622baf59993d7596fda2ad1cf1ef3
parent904a6bd7f451ad9b2cb75ad8e2128ef0418113dc
md/raid1: fix counting of write targets.

commit 964147d5c86d63be79b442c30f3783d49860c078 upstream.

There is a very small race window when writing to a
RAID1 such that if a device is marked faulty at exactly the wrong
time, the write-in-progress will not be sent to the device,
but the bitmap (if present) will be updated to say that
the write was sent.

Then if the device turned out to still be usable as was re-added
to the array, the bitmap-based-resync would skip resyncing that
block, possibly leading to corruption.  This would only be a problem
if no further writes were issued to that area of the device (i.e.
that bitmap chunk).

Suitable for any pending -stable kernel.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/md/raid1.c