Commit ba8805b9 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5.c: add proper locking to error path of raid5_start_reshape. 



If raid5_start_reshape errors out, we need to reset all the fields
that were updated (not just some), and need to use the seq_counter
to ensure make_request() doesn't use an inconsitent state.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 02e5f5c0

drivers/md/raid5.c

+6 −0
Original line number Diff line number Diff line
@@ -6384,12 +6384,18 @@ static int raid5_start_reshape(struct mddev *mddev) 
	if (!mddev->sync_thread) {

		mddev->recovery = 0;

		spin_lock_irq(&conf->device_lock);

		write_seqcount_begin(&conf->gen_lock);

		mddev->raid_disks = conf->raid_disks = conf->previous_raid_disks;

		mddev->new_chunk_sectors =

			conf->chunk_sectors = conf->prev_chunk_sectors;

		mddev->new_layout = conf->algorithm = conf->prev_algo;

		rdev_for_each(rdev, mddev)

			rdev->new_data_offset = rdev->data_offset;

		smp_wmb();

		conf->generation --;

		conf->reshape_progress = MaxSector;

		mddev->reshape_position = MaxSector;

		write_seqcount_end(&conf->gen_lock);

		spin_unlock_irq(&conf->device_lock);

		return -EAGAIN;

	}