Description of problem:
After 'dmsetup remove_all' is executed in an environment that
many maps exist, some maps remain even though those maps aren't used.


Version-Release number of selected component:
device-mapper-1.02.09-1.0.RHEL5
kernel-2.6.17-1.2519.4.5.el5


How reproducible:
Rare


Steps to Reproduce:
 1. umount and deactivate all device-mapper devices.
    (e.g. LVM2 volume, dmraid devices, dm-multipath devices.)
 2. Run attached script.
      # ./dmsetup-remove-all-fail.sh

 The attached script do the following:
    o Create a file and setup a loop-back device by using the file
    o Repeat 100 linear maps creation with using the loop-back device,
      'sleep 3' and 'dmsetup remove_all'.
    o The test stops when the problem occurs or after 1000 trials.


Actual results:
The script stops with 'Exit test.' message below.
At the time, some maps remain even though those maps aren't used
and 'device-mapper: ioctl: remove_all left 1 open device(s)' message
is output in the system console.
--------------------------------------------------------------------
[root@nec-em8 ~]# ./dmsetup-remove-all-fail.sh
INFO: Creating a file for loop setup. file=tmpfile
100+0 records in
100+0 records out
51200 bytes (51 kB) copied, 0.00155528 seconds, 32.9 MB/s
INFO: Setting up loop device. dev=/dev/loop0 file=tmpfile
INFO: Start map create/remove testing.
INFO: Test stops when a problem occurs or after 1000 trials.
INFO: Start TRIAL 0
INFO: Creating linear maps. nr_map=100
INFO: Removing all maps.
ERROR: The problem occurs. Exit test.
INFO: Manual clean-up is needed.
[root@nec-em8 ~]#
[root@nec-em8 ~]# dmsetup ls
testmap13       (253, 13)
[root@nec-em8 ~]#
--------------------------------------------------------------------


Expected results:
The script finishes with 'INFO: Test finished with no problem.' message.


Additional info:
The remaining map(s) can be removed by 'dmsetup remove' or
'dmsetup remove_all' again.

This problem doesn't occur in RHEL4 U4.
This problem seems not occurring in a few maps environment.

Another problem below occurs rarely instead of the problem above.
  o all maps are removed
  o all devices are removed from /dev/mapper/
  o but sysfs entry remains in /sys/block/
Attached script detects this problem too and stops.