md: remove recovery_disabled

'recovery_disabled' logic is complex and confusing, originally intended to
preserve raid in extreme scenarios. It was used in following cases:
- When sync fails and setting badblocks also fails, kick out non-In_sync
  rdev and block spare rdev from joining to preserve raid [1]
- When last backup is unavailable, prevent repeated add-remove of spares
  triggering recovery [2]

The original issues are now resolved:
- Error handlers in all raid types prevent last rdev from being kicked out
- Disks with failed recovery are marked Faulty and can't re-join

Therefore, remove 'recovery_disabled' as it's no longer needed.

[1] 5389042 ("md: change managed of recovery_disabled.")
[2] 4044ba5 ("md: don't retry recovery of raid1 that fails due to error on source drive.")

Link: https://lore.kernel.org/linux-raid/[email protected]
Signed-off-by: Li Nan <[email protected]>
Signed-off-by: Yu Kuai <[email protected]>

Author: Li Nan

drivers/md/md.c

@@ -2618,9 +2618,6 @@ static int bind_rdev_to_array(struct md_rdev *rdev, struct mddev *mddev)
 	list_add_rcu(&rdev->same_set, &mddev->disks);
 	bd_link_disk_holder(rdev->bdev, mddev->gendisk);
 
-	/* May as well allow recovery to be retried once */
-	mddev->recovery_disabled++;
-
 	return 0;
 
  fail:

drivers/md/md.h

@@ -505,12 +505,6 @@ struct mddev {
 	int				ok_start_degraded;
 
 	unsigned long			recovery;
-	/* If a RAID personality determines that recovery (of a particular
-	 * device) will fail due to a read error on the source device, it
-	 * takes a copy of this number and does not attempt recovery again
-	 * until this number changes.
-	 */
-	int				recovery_disabled;
 
 	int				in_sync;	/* know to not need resync */
 	/* 'open_mutex' avoids races between 'md_open' and 'do_md_stop', so

drivers/md/raid1.c

@@ -1760,7 +1760,6 @@ static void raid1_error(struct mddev *mddev, struct md_rdev *rdev)
 		set_bit(MD_BROKEN, &mddev->flags);
 
 		if (!test_bit(MD_FAILLAST_DEV, &mddev->flags)) {
-			conf->recovery_disabled = mddev->recovery_disabled;
 			spin_unlock_irqrestore(&conf->device_lock, flags);
 			return;
 		}
@@ -1904,7 +1903,6 @@ static bool raid1_remove_conf(struct r1conf *conf, int disk)
 
 	/* Only remove non-faulty devices if recovery is not possible. */
 	if (!test_bit(Faulty, &rdev->flags) &&
-	    rdev->mddev->recovery_disabled != conf->recovery_disabled &&
 	    rdev->mddev->degraded < conf->raid_disks)
 		return false;
 
@@ -1924,9 +1922,6 @@ static int raid1_add_disk(struct mddev *mddev, struct md_rdev *rdev)
 	int first = 0;
 	int last = conf->raid_disks - 1;
 
-	if (mddev->recovery_disabled == conf->recovery_disabled)
-		return -EBUSY;
-
 	if (rdev->raid_disk >= 0)
 		first = last = rdev->raid_disk;
 
@@ -2346,7 +2341,6 @@ static void sync_request_write(struct mddev *mddev, struct r1bio *r1_bio)
 		 */
 		if (test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) ||
 		    !fix_sync_read_error(r1_bio)) {
-			conf->recovery_disabled = mddev->recovery_disabled;
 			md_done_sync(mddev, r1_bio->sectors);
 			md_sync_error(mddev);
 			put_buf(r1_bio);
@@ -2948,16 +2942,12 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr,
 		*skipped = 1;
 		put_buf(r1_bio);
 
-		if (!ok) {
-			/* Cannot record the badblocks, so need to
+		if (!ok)
+			/* Cannot record the badblocks, md_error has set INTR,
 			 * abort the resync.
-			 * If there are multiple read targets, could just
-			 * fail the really bad ones ???
 			 */
-			conf->recovery_disabled = mddev->recovery_disabled;
-			set_bit(MD_RECOVERY_INTR, &mddev->recovery);
 			return 0;
-		} else
+		else
 			return min_bad;
 
 	}
@@ -3144,7 +3134,6 @@ static struct r1conf *setup_conf(struct mddev *mddev)
 	init_waitqueue_head(&conf->wait_barrier);
 
 	bio_list_init(&conf->pending_bio_list);
-	conf->recovery_disabled = mddev->recovery_disabled - 1;
 
 	err = -EIO;
 	for (i = 0; i < conf->raid_disks * 2; i++) {

drivers/md/raid1.h

@@ -93,11 +93,6 @@ struct r1conf {
 	 */
 	int			fullsync;
 
-	/* When the same as mddev->recovery_disabled we don't allow
-	 * recovery to be attempted as we expect a read error.
-	 */
-	int			recovery_disabled;
-
 	mempool_t		*r1bio_pool;
 	mempool_t		r1buf_pool;
 

drivers/md/raid10.c

@@ -2130,8 +2130,6 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
 		mirror = first;
 	for ( ; mirror <= last ; mirror++) {
 		p = &conf->mirrors[mirror];
-		if (p->recovery_disabled == mddev->recovery_disabled)
-			continue;
 		if (p->rdev) {
 			if (test_bit(WantReplacement, &p->rdev->flags) &&
 			    p->replacement == NULL && repl_slot < 0)
@@ -2143,7 +2141,6 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
 		if (err)
 			return err;
 		p->head_position = 0;
-		p->recovery_disabled = mddev->recovery_disabled - 1;
 		rdev->raid_disk = mirror;
 		err = 0;
 		if (rdev->saved_raid_disk != mirror)
@@ -2196,7 +2193,6 @@ static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
 	 * is not possible.
 	 */
 	if (!test_bit(Faulty, &rdev->flags) &&
-	    mddev->recovery_disabled != p->recovery_disabled &&
 	    (!p->replacement || p->replacement == rdev) &&
 	    number < conf->geo.raid_disks &&
 	    enough(conf, -1)) {
@@ -2535,8 +2531,6 @@ static void fix_recovery_read_error(struct r10bio *r10_bio)
 					pr_notice("md/raid10:%s: recovery aborted due to read error\n",
 						  mdname(mddev));
 
-					conf->mirrors[dw].recovery_disabled
-						= mddev->recovery_disabled;
 					set_bit(MD_RECOVERY_INTR,
 						&mddev->recovery);
 					break;
@@ -4075,8 +4069,6 @@ static int raid10_run(struct mddev *mddev)
 		    disk->replacement->saved_raid_disk < 0) {
 			conf->fullsync = 1;
 		}
-
-		disk->recovery_disabled = mddev->recovery_disabled - 1;
 	}
 
 	if (mddev->resync_offset != MaxSector)

drivers/md/raid10.h

@@ -18,11 +18,6 @@
 struct raid10_info {
 	struct md_rdev	*rdev, *replacement;
 	sector_t	head_position;
-	int		recovery_disabled;	/* matches
-						 * mddev->recovery_disabled
-						 * when we shouldn't try
-						 * recovering this device.
-						 */
 };
 
 struct r10conf {

drivers/md/raid5.c

@@ -2922,7 +2922,6 @@ static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
 
 	if (has_failed(conf)) {
 		set_bit(MD_BROKEN, &conf->mddev->flags);
-		conf->recovery_disabled = mddev->recovery_disabled;
 
 		pr_crit("md/raid:%s: Cannot continue operation (%d/%d failed).\n",
 			mdname(mddev), mddev->degraded, conf->raid_disks);
@@ -3727,10 +3726,8 @@ handle_failed_sync(struct r5conf *conf, struct stripe_head *sh,
 	}
 	md_done_sync(conf->mddev, RAID5_STRIPE_SECTORS(conf));
 
-	if (abort) {
-		conf->recovery_disabled = conf->mddev->recovery_disabled;
+	if (abort)
 		md_sync_error(conf->mddev);
-	}
 }
 
 static int want_replace(struct stripe_head *sh, int disk_idx)
@@ -7548,8 +7545,6 @@ static struct r5conf *setup_conf(struct mddev *mddev)
 	}
 
 	conf->bypass_threshold = BYPASS_THRESHOLD;
-	conf->recovery_disabled = mddev->recovery_disabled - 1;
-
 	conf->raid_disks = mddev->raid_disks;
 	if (mddev->reshape_position == MaxSector)
 		conf->previous_raid_disks = mddev->raid_disks;
@@ -8249,7 +8244,6 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
 	 * isn't possible.
 	 */
 	if (!test_bit(Faulty, &rdev->flags) &&
-	    mddev->recovery_disabled != conf->recovery_disabled &&
 	    !has_failed(conf) &&
 	    (!p->replacement || p->replacement == rdev) &&
 	    number < conf->raid_disks) {
@@ -8310,8 +8304,6 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
 
 		return 0;
 	}
-	if (mddev->recovery_disabled == conf->recovery_disabled)
-		return -EBUSY;
 
 	if (rdev->saved_raid_disk < 0 && has_failed(conf))
 		/* no point adding a device */

drivers/md/raid5.h

@@ -640,7 +640,6 @@ struct r5conf {
 					    * (fresh device added).
 					    * Cleared when a sync completes.
 					    */
-	int			recovery_disabled;
 	/* per cpu variables */
 	struct raid5_percpu __percpu *percpu;
 	int scribble_disks;