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Commit 7f0da59b authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5: use bad-block log to improve handling of uncorrectable read errors. 



If we get an uncorrectable read error - record a bad block rather than
failing the device.
And if these errors (which may be due to known bad blocks) cause
recovery to be impossible, record a bad block on the recovering
devices, or abort the recovery.

As we might abort a recovery without failing a device we need to teach
RAID5 about recovery_disabled handling.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 31c176ec

drivers/md/raid5.c

+52 −7
Original line number Diff line number Diff line
@@ -2232,9 +2232,18 @@ handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh, 
			rcu_read_lock();

			rdev = rcu_dereference(conf->disks[i].rdev);

			if (rdev && test_bit(In_sync, &rdev->flags))

				/* multiple read failures in one stripe */

				md_error(conf->mddev, rdev);

				atomic_inc(&rdev->nr_pending);

			else

				rdev = NULL;

			rcu_read_unlock();

			if (rdev) {

				if (!rdev_set_badblocks(

					    rdev,

					    sh->sector,

					    STRIPE_SECTORS, 0))

					md_error(conf->mddev, rdev);

				rdev_dec_pending(rdev, conf->mddev);

			}

		}

		spin_lock_irq(&conf->device_lock);

		/* fail all writes first */
@@ -2313,6 +2322,41 @@ handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh, 
			md_wakeup_thread(conf->mddev->thread);

}



static void

handle_failed_sync(raid5_conf_t *conf, struct stripe_head *sh,

		   struct stripe_head_state *s)

{

	int abort = 0;

	int i;



	md_done_sync(conf->mddev, STRIPE_SECTORS, 0);

	clear_bit(STRIPE_SYNCING, &sh->state);

	s->syncing = 0;

	/* There is nothing more to do for sync/check/repair.

	 * For recover we need to record a bad block on all

	 * non-sync devices, or abort the recovery

	 */

	if (!test_bit(MD_RECOVERY_RECOVER, &conf->mddev->recovery))

		return;

	/* During recovery devices cannot be removed, so locking and

	 * refcounting of rdevs is not needed

	 */

	for (i = 0; i < conf->raid_disks; i++) {

		mdk_rdev_t *rdev = conf->disks[i].rdev;

		if (!rdev

		    || test_bit(Faulty, &rdev->flags)

		    || test_bit(In_sync, &rdev->flags))

			continue;

		if (!rdev_set_badblocks(rdev, sh->sector,

					STRIPE_SECTORS, 0))

			abort = 1;

	}

	if (abort) {

		conf->recovery_disabled = conf->mddev->recovery_disabled;

		set_bit(MD_RECOVERY_INTR, &conf->mddev->recovery);

	}

}



/* fetch_block - checks the given member device to see if its data needs

 * to be read or computed to satisfy a request.

 *
@@ -3067,11 +3111,8 @@ static void handle_stripe(struct stripe_head *sh) 
	 */

	if (s.failed > conf->max_degraded && s.to_read+s.to_write+s.written)

		handle_failed_stripe(conf, sh, &s, disks, &s.return_bi);

	if (s.failed > conf->max_degraded && s.syncing) {

		md_done_sync(conf->mddev, STRIPE_SECTORS, 0);

		clear_bit(STRIPE_SYNCING, &sh->state);

		s.syncing = 0;

	}

	if (s.failed > conf->max_degraded && s.syncing)

		handle_failed_sync(conf, sh, &s);



	/*

	 * might be able to return some write requests if the parity blocks
@@ -4976,6 +5017,7 @@ static int raid5_remove_disk(mddev_t *mddev, int number) 
		 * isn't possible.

		 */

		if (!test_bit(Faulty, &rdev->flags) &&

		    mddev->recovery_disabled != conf->recovery_disabled &&

		    !has_failed(conf) &&

		    number < conf->raid_disks) {

			err = -EBUSY;
@@ -5004,6 +5046,9 @@ static int raid5_add_disk(mddev_t *mddev, mdk_rdev_t *rdev) 
	int first = 0;

	int last = conf->raid_disks - 1;



	if (mddev->recovery_disabled == conf->recovery_disabled)

		return -EBUSY;



	if (has_failed(conf))

		/* no point adding a device */

		return -EINVAL;

drivers/md/raid5.h

+1 −1
Original line number Diff line number Diff line
@@ -399,7 +399,7 @@ struct raid5_private_data { 
					    * (fresh device added).

					    * Cleared when a sync completes.

					    */



	int			recovery_disabled;

	/* per cpu variables */

	struct raid5_percpu {

		struct page	*spare_page; /* Used when checking P/Q in raid6 */