losetup: raspbian-20200505.img: failed to set up loop device: Device or resource busy

Question

I am trying to shrink the image file from raspbian in Ubuntu18 so that it become small in size and easy to transfer. I am following this video where the person uses below command to setup a loop device

sudo losetup /dev/loop0 raspbian-20200505.img -o $((532480*512))

But it gives me error:

losetup: raspbian-20200505.img: failed to set up loop device: Device or resource busy

Can anyone please tell me what is the reason for this error and how can I resolve it. Please help. Thanks

You haven't mentioned OS/release details, however your filename implies Raspbian which is neither Ubuntu, nor flavor of Ubuntu (https://ubuntu.com/download/flavours) - https://askubuntu.com/help/on-topic — guiverc, May 24 '20 at 04:55
@guiverc I am in ubuntu and trying to shrink image file of raspbian — S Andrew, May 24 '20 at 05:08
If you run df -h it will show you all the /dev/loop# that are in use. Pick the next one that is not in use like /dev/loop18 or something like that. — Terrance, May 24 '20 at 05:12

Terrance · Accepted Answer · 2023-07-25T22:37:54.593

EDIT 2023-07-25: This answer was written before 22.04 when they changed df to no longer list loop mounts. Now you can use lsblk to show the loops.

It is giving you that message because /dev/loop0 is already in use. If you run the command of df -h (disk free) which shows you all your mounts that are in use as well as all the /dev/loop# mounts. Pick the next /dev/loop# that is not in use for your command.

Example:

df -h
Filesystem                 Size  Used Avail Use% Mounted on
udev                       7.8G     0  7.8G   0% /dev
tmpfs                      1.6G  6.9M  1.6G   1% /run
/dev/sde1                  212G   92G  109G  46% /
tmpfs                      7.9G   49M  7.8G   1% /dev/shm
tmpfs                      5.0M  4.0K  5.0M   1% /run/lock
tmpfs                      7.9G     0  7.9G   0% /sys/fs/cgroup
/dev/loop0                 9.2M  9.2M     0 100% /snap/canonical-livepatch/95
/dev/loop1                 172M  172M     0 100% /snap/qt551/27
/dev/loop2                 161M  161M     0 100% /snap/gnome-3-28-1804/116
/dev/loop3                 227M  227M     0 100% /snap/wine-platform-runtime/136
/dev/loop4                  63M   63M     0 100% /snap/gtk-common-themes/1506
/dev/loop5                  94M   94M     0 100% /snap/core/9066
/dev/loop6                 173M  173M     0 100% /snap/qt551/28
/dev/loop7                  55M   55M     0 100% /snap/core18/1705
/dev/loop8                  94M   94M     0 100% /snap/core/8935
/dev/loop9                  55M   55M     0 100% /snap/gtk-common-themes/1502
/dev/loop10                 74M   74M     0 100% /snap/wine-platform-3-stable/6
/dev/loop11                141M  141M     0 100% /snap/gnome-3-26-1604/98
/dev/loop12                 55M   55M     0 100% /snap/core18/1754
/dev/loop13                 55M   55M     0 100% /snap/bitwarden/24
/dev/loop14                227M  227M     0 100% /snap/wine-platform-runtime/123
/dev/loop15                 55M   55M     0 100% /snap/bitwarden/23
/dev/loop16                157M  157M     0 100% /snap/gnome-3-28-1804/110
/dev/loop17                141M  141M     0 100% /snap/gnome-3-26-1604/97
/dev/sdf2                  224G  173G   51G  78% /media/Windows
/dev/sdh1                  932G  774G  159G  84% /media/1TB_SHARE
/dev/sdg1                  466G  268G  199G  58% /media/WD500GB
/dev/sda1                  233G  177G   57G  76% /media/250GB_SHARE
/dev/sdd1                  466G   85G  382G  19% /media/ST500GB
/dev/sdc1                  466G  284G  182G  61% /media/500GB
/dev/sdb1                  2.8T  963G  1.8T  35% /media/Seagate

as we can see in the above /dev/loop0-17 are all in use, so the next one we can use is /dev/loop18 for the command.

sudo losetup /dev/loop18 raspbian-20200505.img -o $((532480*512))

df does not show the loop devices on my system, but lsblk does — ocroquette, Jul 25 '23 at 15:59
@ocroquette Thank you for your comment. You are correct. Around the release of 22.04 they stopped having df list the loop devices. I added a note at this answer reflecting that. Thank you! :) — Terrance, Jul 25 '23 at 22:38

losetup: raspbian-20200505.img: failed to set up loop device: Device or resource busy

1 Answers1