Am 07.03.2018 um 19:35 schrieb Jim Perrin jperrin@centos.org:

On 03/07/2018 04:48 AM, Leon Fauster wrote:

...

OS: EL6 - sometimes I use

kpartx -a /mnt/.../lvdisk.img

to map the partitions and mount them via

/dev/mapper/loop0pX

After using the disk (unmounting it) I noticed that detaching such mapping via kpartx -d does not result in freeing up the loop devices. Results: System reboots shows that the filesystem where lvdisk.img is located can't be unmounted.

lsof, fuser, ps does not show any usage. Even removing the device node via

dmsetup remove /dev/mapper/loop0pX

does not help. Trying to unmount the underlying filesystem still shows /mnt: device is busy.

Any other suggestions would be greatly appreciated!

Do you have an open shell/terminal session hanging out in the /mnt directory you used?

With some heuristic I got following results (briefly):

Jumping into the image/file directory and adding the partition map (kpartx -a) and removing it (kpartx -d) works!

So the output of losetup between this two activities shows:

losetup -a /dev/loop0: [0821]:130822 (kvm-system-centos6_x86_64-devel-lv_vm_intern_spare.img)

but when adding the partition map with an absolut _long_ path detaching/deleting the map doesn't work.

losetup -a /dev/loop0: [0821]:130822 (/mnt/pool/VirtLibrary/3-live/kvm-system-centos6_x86_64-devel-l*)

shortening the path and adding the partition map with an absolut path and removing it works again.

losetup -a /dev/loop0: [0821]:130822 (/mnt/kvm-system-centos6_x86_64-devel-lv_vm_intern_spare.img)

So, is kpartx or the underlying loop handle limited to a 64 character long file pointer?

Anyway, at least I can work around it ...

-- LF