Commit 8c2e870a authored Jun 28, 2008 by Neil Brown

Ensure interrupted recovery completed properly (v1 metadata plus bitmap)



If, while assembling an array, we find a device which is not fully
in-sync with the array, it is important to set the "fullsync" flags.
This is an exact analog to the setting of this flag in hot_add_disk
methods.

Currently, only v1.x metadata supports having devices in an array
which are not fully in-sync (it keep track of how in sync they are).
The 'fullsync' flag only makes a difference when a write-intent bitmap
is being used.  In this case it tells recovery to ignore the bitmap
and recovery all blocks.

This fix is already in place for raid1, but not raid5/6 or raid10.

So without this fix, a raid1 ir raid4/5/6 array with version 1.x
metadata and a write intent bitmaps, that is stopped in the middle
of a recovery, will appear to complete the recovery instantly
after it is reassembled, but the recovery will not be correct.

If you might have an array like that, issueing
   echo repair > /sys/block/mdXX/md/sync_action

will make sure recovery completes properly.

Cc: <stable@kernel.org>
Signed-off-by: Neil Brown <neilb@suse.de>

parent 543cf4cb

drivers/md/raid10.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -2137,6 +2137,8 @@ static int run(mddev_t *mddev)
		!test_bit(In_sync, &disk->rdev->flags)) {
		disk->head_position = 0;
		mddev->degraded++;
		if (disk->rdev)
		conf->fullsync = 1;
		}
		}

drivers/md/raid5.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -4305,7 +4305,9 @@ static int run(mddev_t *mddev)
		" disk %d\n", bdevname(rdev->bdev,b),
		raid_disk);
		working_disks++;
		}
		} else
		/* Cannot rely on bitmap to complete recovery */
		conf->fullsync = 1;
		}

		/*

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