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    Subject[patch 08/47] md: Ensure interrupted recovery completed properly (v1 metadata plus bitmap)
    2.6.25-stable review patch.  If anyone has any objections, please let us
    know.

    ------------------
    From: Neil Brown <neilb@notabene.brown>

    commit 8c2e870a625bd336b2e7a65a97c1836acef07322 upstream

    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.

    Signed-off-by: Neil Brown <neilb@suse.de>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

    ---
    drivers/md/raid10.c | 2 ++
    drivers/md/raid5.c | 4 +++-
    2 files changed, 5 insertions(+), 1 deletion(-)

    --- a/drivers/md/raid10.c
    +++ b/drivers/md/raid10.c
    @@ -2102,6 +2102,8 @@ 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;
    }
    }

    --- a/drivers/md/raid5.c
    +++ b/drivers/md/raid5.c
    @@ -4166,7 +4166,9 @@ 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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