[dm-devel] Can not remove device. No files open, no processes attached. Forced to reboot server.

[Aidan Walton]

Hi,
I've been chasing a problem now for a few weeks. I have a flaky SATA
controller that fails unpredictably and upon doing so all drives
attached are disconnected by the kernel. I have 2 discs on this
controller which are the components of a RAID1 array. mdraid fails the
disc (in its strange way) stating that one device is removed and the
other is active. Apparently this is the default mdraid approach. Even
though both devices are in fact failed. Regardless, the devmapper
device which is supporting an LVM logical volume on top of this raid
array, remains active. The logical volume is no longer listed by
lvdisplay, but dmsetup -c info shows:
Name                                Maj Min Stat Open Targ Event  UUID
storage.mx.vg2-shared_sun_NAS.lv1   253   2 L--w    1    1      0
LVM-Ud9pj6QE4hK1K3xiAFMVCnno3SrXaRyTXJLtTGDOPjBUppJgzr4t0jJowixEOtx7
storage.mx.vg1-shared_sun_users.lv1 253   1 L--w    1    1      0
LVM-ypcHlbNXu36FLRgU0EcUiXBSIvcOlHEP3MHkBKsBeHf6Q68TIuGA9hd5UfCpvOeo
ubuntu_server--vg-ubuntu_server--lv 253   0 L--w    1    1      0
LVM-eGBUJxP1vlW3MfNNeC2r5JfQUiKKWZ73t3U3Jji3lggXe8LPrUf0xRE0YyPzSorO

The device in question is 'storage.mx.vg2-shared_sun_NAS.lv1'

As can be seen is displays 'open'

however lsof /dev/mapper/storage.mx.vg2-shared_sun_NAS.lv1
<blank>

fuser -m /dev/storage.mx.vg1/shared_sun_users.lv1
<blank>

dmsetup status storage.mx.vg2-shared_sun_NAS.lv1
0 976502784 error

dmsetup remove storage.mx.vg2-shared_sun_NAS.lv1
device-mapper: remove ioctl on storage.mx.vg2-shared_sun_NAS.lv1
failed: Device or resource busy

dmsetup wipe_table storage.mx.vg2-shared_sun_NAS.lv1
device-mapper: resume ioctl on storage.mx.vg2-shared_sun_NAS.lv1
failed: Invalid argument


and so on. Nothing appears to be attached to this device but it
refuses to be removed. As a consequence I can not disable the mdraid
array and can not recover the controller. Which is possible by
resetting the pci slot.

Currently the only possible way I have to recover this problem is to
reboot the server.

Please see.
https://marc.info/?l=linux-raid&m=164159457011525&w=2

for the discussion regarding the same problem on the linux-raid mailing list.
No progress so far, help appreciated
Aidan