Am 07.03.2018 um 19:35 schrieb Jim Perrin <jperrin at 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