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Commit 5024c298 authored by NeilBrown's avatar NeilBrown
Browse files

md: Remove recent change which allows devices to skip recovery. 



commit 7ceb17e8
    md: Allow devices to be re-added to a read-only array.

allowed a bit more than just that.  It also allows devices to be added
to a read-write array and to end up skipping recovery.

This patch removes the offending piece of code pending a rewrite for a
subsequent release.

More specifically:
 If the array has a bitmap, then the device will still need a bitmap
 based resync ('saved_raid_disk' is set under different conditions
 is a bitmap is present).
 If the array doesn't have a bitmap, then this is correct as long as
 nothing has been written to the array since the metadata was checked
 by ->validate_super.  However there is no locking to ensure that there
 was no write.

Bug was introduced in 3.10 and causes data corruption so
patch is suitable for 3.10-stable.

Cc: stable@vger.kernel.org (3.10)
Reported-by: default avatarJoe Lawrence <joe.lawrence@stratus.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 7bb23c49

drivers/md/md.c

+0 −14
Original line number Diff line number Diff line
@@ -7716,20 +7716,6 @@ static int remove_and_add_spares(struct mddev *mddev, 
			continue;



		rdev->recovery_offset = 0;

		if (rdev->saved_raid_disk >= 0 && mddev->in_sync) {

			spin_lock_irq(&mddev->write_lock);

			if (mddev->in_sync)

				/* OK, this device, which is in_sync,

				 * will definitely be noticed before

				 * the next write, so recovery isn't

				 * needed.

				 */

				rdev->recovery_offset = mddev->recovery_cp;

			spin_unlock_irq(&mddev->write_lock);

		}

		if (mddev->ro && rdev->recovery_offset != MaxSector)

			/* not safe to add this disk now */

			continue;

		if (mddev->pers->

		    hot_add_disk(mddev, rdev) == 0) {

			if (sysfs_link_rdev(mddev, rdev))