Error in rebuild of two "layered" md devices in container

Hi Neil,

found another bug.

- Created a container with six disks
- Created two md devices in it:

mdadm -CR /dev/md0 -l 6 -n 6 -z 50M
mdadm -CR /dev/md1 -l 5 -n 6 -z 50M

The md devices are "layered" in the container across all disks.

They both get build and are online.

- Fail one disk, both md devices are affected
- Remove disk
- Clear superblock of removed disk
- Add disk again (in essence, I just added a spare disk)

Now comes the error:

- md0 is rebuild
- md1 is NOT rebuild

Personalities : [raid6] [raid5] [raid4] [raid1]
md1 : active raid6 sde[6] sdg[5] sdf[4] sdd[2] sdc[1] sdb[0]
      204800 blocks super external:/md127/1 level 6, 512k chunk,
algorithm 10 [6/6] [UUUUUU]

md0 : active raid5 sdb[6] sdg[5] sdf[4] sdd[2] sdc[1]
      256000 blocks super external:/md127/0 level 5, 512k chunk,
algorithm 2 [6/5] [UUU_UU]

md127 : inactive sde[3](S) sdb[0](S) sdg[5](S) sdf[4](S) sdd[2](S) sdc[1](S)
      196608 blocks super external:ddf

unused devices: <none>

 Physical Disks : 6
      Number    RefNo      Size       Device      Type/State
         0    cb5ea6c1   1015808K /dev/sdc        active/Online
         1    a7f8ed2f   1015808K /dev/sdd        active/Online
         2    f769a815   1015808K /dev/sdf        active/Online
         3    025e6835   1015808K /dev/sdg        active/Online
         4    b22e9e4d   1015808K /dev/sdb        active/Online
         5    b4cccecc   1015808K /dev/sde        active/Online


Albert