From 2bb77736ae5dca0a189829fbb7379d43364a9dac Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Wed, 27 Jul 2011 11:00:36 +1000
Subject: [PATCH] md/raid10: Make use of new recovery_disabled handling

When we get a read error during recovery, RAID10 previously
arranged for the recovering device to appear to fail so that
the recovery stops and doesn't restart.  This is misleading and wrong.

Instead, make use of the new recovery_disabled handling and mark
the target device and having recovery disabled.

Add appropriate checks in add_disk and remove_disk so that devices
are removed and not re-added when recovery is disabled.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 drivers/md/raid10.c | 62 ++++++++++++++++++++++++++-------------------
 drivers/md/raid10.h |  5 ++++
 2 files changed, 41 insertions(+), 26 deletions(-)

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 1725ec1e1e82..5583201e5cde 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1099,7 +1099,6 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 	conf_t *conf = mddev->private;
 	int err = -EEXIST;
 	int mirror;
-	mirror_info_t *p;
 	int first = 0;
 	int last = conf->raid_disks - 1;
 
@@ -1119,32 +1118,36 @@ static int raid10_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 		mirror = rdev->saved_raid_disk;
 	else
 		mirror = first;
-	for ( ; mirror <= last ; mirror++)
-		if ( !(p=conf->mirrors+mirror)->rdev) {
+	for ( ; mirror <= last ; mirror++) {
+		mirror_info_t *p = &conf->mirrors[mirror];
+		if (p->recovery_disabled == mddev->recovery_disabled)
+			continue;
+		if (!p->rdev)
+			continue;
 
-			disk_stack_limits(mddev->gendisk, rdev->bdev,
-					  rdev->data_offset << 9);
-			/* as we don't honour merge_bvec_fn, we must
-			 * never risk violating it, so limit
-			 * ->max_segments to one lying with a single
-			 * page, as a one page request is never in
-			 * violation.
-			 */
-			if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
-				blk_queue_max_segments(mddev->queue, 1);
-				blk_queue_segment_boundary(mddev->queue,
-							   PAGE_CACHE_SIZE - 1);
-			}
-
-			p->head_position = 0;
-			rdev->raid_disk = mirror;
-			err = 0;
-			if (rdev->saved_raid_disk != mirror)
-				conf->fullsync = 1;
-			rcu_assign_pointer(p->rdev, rdev);
-			break;
+		disk_stack_limits(mddev->gendisk, rdev->bdev,
+				  rdev->data_offset << 9);
+		/* as we don't honour merge_bvec_fn, we must
+		 * never risk violating it, so limit
+		 * ->max_segments to one lying with a single
+		 * page, as a one page request is never in
+		 * violation.
+		 */
+		if (rdev->bdev->bd_disk->queue->merge_bvec_fn) {
+			blk_queue_max_segments(mddev->queue, 1);
+			blk_queue_segment_boundary(mddev->queue,
+						   PAGE_CACHE_SIZE - 1);
 		}
 
+		p->head_position = 0;
+		rdev->raid_disk = mirror;
+		err = 0;
+		if (rdev->saved_raid_disk != mirror)
+			conf->fullsync = 1;
+		rcu_assign_pointer(p->rdev, rdev);
+		break;
+	}
+
 	md_integrity_add_rdev(rdev, mddev);
 	print_conf(conf);
 	return err;
@@ -1169,6 +1172,7 @@ static int raid10_remove_disk(mddev_t *mddev, int number)
 		 * is not possible.
 		 */
 		if (!test_bit(Faulty, &rdev->flags) &&
+		    mddev->recovery_disabled != p->recovery_disabled &&
 		    enough(conf)) {
 			err = -EBUSY;
 			goto abort;
@@ -1383,8 +1387,14 @@ static void recovery_request_write(mddev_t *mddev, r10bio_t *r10_bio)
 	md_sync_acct(conf->mirrors[d].rdev->bdev, wbio->bi_size >> 9);
 	if (test_bit(R10BIO_Uptodate, &r10_bio->state))
 		generic_make_request(wbio);
-	else
-		bio_endio(wbio, -EIO);
+	else {
+		printk(KERN_NOTICE
+		       "md/raid10:%s: recovery aborted due to read error\n",
+		       mdname(mddev));
+		conf->mirrors[d].recovery_disabled = mddev->recovery_disabled;
+		set_bit(MD_RECOVERY_INTR, &mddev->recovery);
+		bio_endio(wbio, 0);
+	}
 }
 
 
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index 944b1104d3b4..a485914c48c1 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -6,6 +6,11 @@ typedef struct mirror_info mirror_info_t;
 struct mirror_info {
 	mdk_rdev_t	*rdev;
 	sector_t	head_position;
+	int		recovery_disabled;	/* matches
+						 * mddev->recovery_disabled
+						 * when we shouldn't try
+						 * recovering this device.
+						 */
 };
 
 typedef struct r10bio_s r10bio_t;