From: Martin Wilck <mwilck@arcor.de>
Date: Wed, 24 Apr 2013 01:42:42 +0000 (+1000)
Subject: md/raid10: Allow skipping recovery when clean arrays are assembled
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7e83ccbecd608b971f340e951c9e84cd0343002f;p=GitHub%2Fexynos8895%2Fandroid_kernel_samsung_universal8895.git

md/raid10: Allow skipping recovery when clean arrays are assembled

When an array is assembled incrementally with mdadm -I -R
and the array switches to "active" mode, md starts a recovery.

If the array was clean, the "fullsync" flag will be 0. Skip
the full recovery in this case, as RAID1 does (the code was
actually copied from the sync_request() method of RAID1).

Signed-off-by: Martin Wilck <mwilck@arcor.de>
Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 77b562d18a90..2372926dc559 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2913,6 +2913,22 @@ static sector_t sync_request(struct mddev *mddev, sector_t sector_nr,
 		if (init_resync(conf))
 			return 0;
 
+	/*
+	 * Allow skipping a full rebuild for incremental assembly
+	 * of a clean array, like RAID1 does.
+	 */
+	if (mddev->bitmap == NULL &&
+	    mddev->recovery_cp == MaxSector &&
+	    !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
+	    conf->fullsync == 0) {
+		*skipped = 1;
+		max_sector = mddev->dev_sectors;
+		if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
+		    test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
+			max_sector = mddev->resync_max_sectors;
+		return max_sector - sector_nr;
+	}
+
  skipped:
 	max_sector = mddev->dev_sectors;
 	if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||