Commit 5024c298 authored Jul 17, 2013 by NeilBrown

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: Joe Lawrence <joe.lawrence@stratus.com>
Signed-off-by: NeilBrown <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))

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