Commit 3a9f28a5 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid1: improve handling of read failure during recovery. 



If we cannot read a block from anywhere during recovery, there is
now a better approach than just giving up.
We can record a bad block on each device and keep going - being
careful not to clear the bad block when a write succeeds as it might -
it will be a write of incorrect data.

We have now reached the state where - for raid1 - we only call
md_error if md_set_badblocks has failed.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Reviewed-by: default avatarNamhyung Kim <namhyung@gmail.com>
parent d8f05d29

drivers/md/raid1.c

+34 −7
Original line number Diff line number Diff line
@@ -1392,7 +1392,12 @@ static void end_sync_write(struct bio *bio, int error) 
	} else if (is_badblock(conf->mirrors[mirror].rdev,

			       r1_bio->sector,

			       r1_bio->sectors,

			       &first_bad, &bad_sectors))

			       &first_bad, &bad_sectors) &&

		   !is_badblock(conf->mirrors[r1_bio->read_disk].rdev,

				r1_bio->sector,

				r1_bio->sectors,

				&first_bad, &bad_sectors)

		)

		set_bit(R1BIO_MadeGood, &r1_bio->state);



	update_head_pos(mirror, r1_bio);
@@ -1473,17 +1478,37 @@ static int fix_sync_read_error(r1bio_t *r1_bio) 


		if (!success) {

			char b[BDEVNAME_SIZE];

			/* Cannot read from anywhere, array is toast */

			md_error(mddev, conf->mirrors[r1_bio->read_disk].rdev);

			int abort = 0;

			/* Cannot read from anywhere, this block is lost.

			 * Record a bad block on each device.  If that doesn't

			 * work just disable and interrupt the recovery.

			 * Don't fail devices as that won't really help.

			 */

			printk(KERN_ALERT "md/raid1:%s: %s: unrecoverable I/O read error"

			       " for block %llu\n",

			       mdname(mddev),

			       bdevname(bio->bi_bdev, b),

			       (unsigned long long)r1_bio->sector);

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

				rdev = conf->mirrors[d].rdev;

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

					continue;

				if (!rdev_set_badblocks(rdev, sect, s, 0))

					abort = 1;

			}

			if (abort) {

				mddev->recovery_disabled = 1;

				set_bit(MD_RECOVERY_INTR, &mddev->recovery);

				md_done_sync(mddev, r1_bio->sectors, 0);

				put_buf(r1_bio);

				return 0;

			}

			/* Try next page */

			sectors -= s;

			sect += s;

			idx++;

			continue;

		}



		start = d;

		/* write it back and re-read */
@@ -1879,7 +1904,9 @@ static void raid1d(mddev_t *mddev) 
					if (bio->bi_end_io == NULL)

						continue;

					if (test_bit(BIO_UPTODATE,

						     &bio->bi_flags)) {

						     &bio->bi_flags) &&

					    test_bit(R1BIO_MadeGood,

						     &r1_bio->state)) {

						rdev_clear_badblocks(

							rdev,

							r1_bio->sector,

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