md/raid1: fix counting of write targets.

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.

Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2010-05-18 15:27:13 +10:00
parent a64c876fd3
commit 964147d5c8
1 changed files with 3 additions and 2 deletions

View File

@ -911,9 +911,10 @@ static int make_request(struct request_queue *q, struct bio * bio)
if (test_bit(Faulty, &rdev->flags)) {
rdev_dec_pending(rdev, mddev);
r1_bio->bios[i] = NULL;
} else
} else {
r1_bio->bios[i] = bio;
targets++;
targets++;
}
} else
r1_bio->bios[i] = NULL;
}