1

I have a script that I use to mount diskimages that are LVM images. it does:

x=`losetup -f`       #create a loop device
echo $x > loopdev    #echo that device to a file for later use
losetup $x disk.img  #mount the disk.img to the loop device
kpartx -av $x        #use kpartx to add the partition mappings
vgscan && vgchange -ay   #vgscan the new mappings and make active
mount /dev/VolGroupRoot/LogVolRoot /mnt   #mount the volgroup to /mnt
mount -o loop,offset=$((2048 * 512)) disk.img /mnt/boot    #mount the boot partition in the image to /mnt/boot

This works a charm when there are available loop devices.

Alternatively, to then umount the img I run:

umount /mnt/boot        #umount boot
umount /mnt             #umount volgroup
vgchange -an VolGroupRoot   #make volgroup inactive
x=`cat loopdev`             #get my used loopdevice
kpartx -d $x                #delete the partition mappings
losetup -d $x               #detach the loop device
/bin/rm loopdev             #remove the loopdev file in prep for the next time I mount something using the script.

This runs without errors however, I find that it doesn't always remove the loop device for later use. losetup -a often shows those previously used loop devices still in it's table. dmsetup info doesn't show the loop devices but I do see them with lsof being held by kthreadd. As a result it appears there's no way to remove the /dev/loop devices without a reboot which seems like taking a sledge hammer to the problem. I can (and often do) end up building new loop devices to get around this but that's unsustainable and doesn't address the real issue. has anybody seen this and/or have any other things I can try (fwiw, this is happening on 3.18 and 4.1 kernel systems).

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.