Re: losetup: cannot find an unused loop device , kernel config of loopback device
I seem to have resolved the issue above after rebooting. Thanks for
helping to debug Thomas and everyone.
On Sat, Aug 7, 2021 at 1:29 PM Colin Williams
<colin.williams.seattle@gmail.com> wrote:
>
> > ----------------------------------------------------------------------
> >
> > Do you have a file
> > /dev/loop-control
> > ?
> >
> > What is listed by
> >
> > ls -ld /dev/loop*
> >
>
> colin@M00974055-VM:~$ sudo ls /dev/loop-control
> [sudo] password for colin:
> ls: cannot access '/dev/loop-control': No such file or directory
> colin@M00974055-VM:~$ sudo ls -ld /dev/loop*
> ls: cannot access '/dev/loop*': No such file or directory
>
>
>
> > ----------------------------------------------------------------------
> >
> > What happens if you try to create a loop device manually ?
> >
>
> not_yet_existing_file="some_file_path"
> dd if=/dev/zero bs=512 count=2 of="$not_yet_existing_file"
> sudo losetup loop0 "$not_yet_existing_file"
>
> not_yet_existing_file="/tmp/does_not_exist_yet"
> dd if=/dev/zero bs=512 count=2 of="$not_yet_existing_file"
> sudo losetup loop0 "$not_yet_existing_file"
> 2+0 records in
> 2+0 records out
> 1024 bytes (1.0 kB, 1.0 KiB) copied, 0.000187826 s, 5.5 MB/s
> losetup: /dev/loop0: failed to set up loop device: No such file or directory
>
> > There should be no messages from losetup.
>
> But we see one above ^^
>
> > sudo wc -c </dev/loop0
> > should yield "1024".
>
> sudo wc -c </dev/loop0
> bash: /dev/loop0: No such file or directory
>
>
> > To clean up do:
> >
> losetup -d /dev/loop0
> rm "$not_yet_existing_file"
>
>
> colin@M00974055-VM:~$ sudo losetup -d /dev/loop0
> losetup: /dev/loop0: failed to use device: No such device
> colin@M00974055-VM:~$ rm "$not_yet_existing_file"
> colin@M00974055-VM:~$
>
> ______________________________________________________________________
>
> >
> >
> > Have a nice day :)
> >
> > Thomas
>
>
> Thank you Thomas. Thanks again for looking at my issue. Not sure where
> to go from here.
>
> ________________________________________________________________________
>
> colin@M00974055-VM:~$ uname -r
> 5.10.0-3-amd64
> colin@M00974055-VM:~$ cat /etc/debian_version
> 11.0colin@M00974055-VM:~$ lsmod | grep loop
> colin@M00974055-VM:~$ sudo modprobe loop
> colin@M00974055-VM:~$ lsmod | grep loop
> loop 36864 0
> colin@M00974055-VM:~$ dd if=/dev/zero bs=512 count=2 of="$not_yet_existing_file"
> 2+0 records in
> 2+0 records out
> 1024 bytes (1.0 kB, 1.0 KiB) copied, 0.000134838 s, 7.6 MB/s
> colin@M00974055-VM:~$ sudo losetup loop0 "$not_yet_existing_file"
>
> No error here ^^ Guess we needed to load the module?
>
> colin@M00974055-VM:~$ sudo wc -c </dev/loop0
> bash: /dev/loop0: Permission denied
> colin@M00974055-VM:~$ sudo -i
> root@M00974055-VM:~# wc -c </dev/loop0
> 1024
> root@M00974055-VM:
>
>
> wc -c </dev/loop0
> 1024
> root@M00974055-VM:~# losetup -d /dev/loop0
> rm "$not_yet_existing_file"
> rm: cannot remove '': No such file or directory
>
> I think we are on to something after loading the module
>
> _____________________________________________________________
>
> I re-ran the script after the module. It looks like it's making more
> progress but still getting an eventual error related to loopback
> devices:
>
> http://ix.io/3vi8
>
>
> ^^ This is probably the most useful to look at moving forward ^^
>
> Now I will re-run the inital commands below
>
> sudo ls -ld /dev/loop*
> brw-rw---- 1 root disk 7, 0 Aug 7 13:07 /dev/loop0
> brw-rw---- 1 root disk 259, 12 Aug 7 13:07 /dev/loop0p1
> brw-rw---- 1 root disk 259, 21 Aug 7 13:07 /dev/loop0p10
> brw-rw---- 1 root disk 259, 22 Aug 7 13:07 /dev/loop0p11
> brw-rw---- 1 root disk 259, 23 Aug 7 13:07 /dev/loop0p12
> brw-rw---- 1 root disk 259, 13 Aug 7 13:07 /dev/loop0p2
> brw-rw---- 1 root disk 259, 14 Aug 7 13:07 /dev/loop0p3
> brw-rw---- 1 root disk 259, 15 Aug 7 13:07 /dev/loop0p4
> brw-rw---- 1 root disk 259, 16 Aug 7 13:07 /dev/loop0p5
> brw-rw---- 1 root disk 259, 17 Aug 7 13:07 /dev/loop0p6
> brw-rw---- 1 root disk 259, 18 Aug 7 13:07 /dev/loop0p7
> brw-rw---- 1 root disk 259, 19 Aug 7 13:07 /dev/loop0p8
> brw-rw---- 1 root disk 259, 20 Aug 7 13:07 /dev/loop0p9
> brw-rw---- 1 root disk 7, 1 Aug 7 13:01 /dev/loop1
> brw-rw---- 1 root disk 259, 0 Aug 7 13:01 /dev/loop1p1
> brw-rw---- 1 root disk 259, 9 Aug 7 13:01 /dev/loop1p10
> brw-rw---- 1 root disk 259, 10 Aug 7 13:01 /dev/loop1p11
> brw-rw---- 1 root disk 259, 11 Aug 7 13:01 /dev/loop1p12
> brw-rw---- 1 root disk 259, 1 Aug 7 13:01 /dev/loop1p2
> brw-rw---- 1 root disk 259, 2 Aug 7 13:01 /dev/loop1p3
> brw-rw---- 1 root disk 259, 3 Aug 7 13:01 /dev/loop1p4
> brw-rw---- 1 root disk 259, 4 Aug 7 13:01 /dev/loop1p5
> brw-rw---- 1 root disk 259, 5 Aug 7 13:01 /dev/loop1p6
> brw-rw---- 1 root disk 259, 6 Aug 7 13:01 /dev/loop1p7
> brw-rw---- 1 root disk 259, 7 Aug 7 13:01 /dev/loop1p8
> brw-rw---- 1 root disk 259, 8 Aug 7 13:01 /dev/loop1p9
> brw-rw---- 1 root disk 7, 2 Aug 7 13:09 /dev/loop2
> brw-rw---- 1 root disk 259, 24 Aug 7 13:09 /dev/loop2p1
> brw-rw---- 1 root disk 259, 33 Aug 7 13:09 /dev/loop2p10
> brw-rw---- 1 root disk 259, 34 Aug 7 13:09 /dev/loop2p11
> brw-rw---- 1 root disk 259, 35 Aug 7 13:09 /dev/loop2p12
> brw-rw---- 1 root disk 259, 25 Aug 7 13:09 /dev/loop2p2
> brw-rw---- 1 root disk 259, 26 Aug 7 13:09 /dev/loop2p3
> brw-rw---- 1 root disk 259, 27 Aug 7 13:09 /dev/loop2p4
> brw-rw---- 1 root disk 259, 28 Aug 7 13:09 /dev/loop2p5
> brw-rw---- 1 root disk 259, 29 Aug 7 13:09 /dev/loop2p6
> brw-rw---- 1 root disk 259, 30 Aug 7 13:09 /dev/loop2p7
> brw-rw---- 1 root disk 259, 31 Aug 7 13:09 /dev/loop2p8
> brw-rw---- 1 root disk 259, 32 Aug 7 13:09 /dev/loop2p9
> brw-rw---- 1 root disk 7, 3 Aug 7 12:59 /dev/loop3
> brw-rw---- 1 root disk 7, 4 Aug 7 12:59 /dev/loop4
> brw-rw---- 1 root disk 7, 5 Aug 7 12:59 /dev/loop5
> brw-rw---- 1 root disk 7, 6 Aug 7 12:59 /dev/loop6
> brw-rw---- 1 root disk 7, 7 Aug 7 12:59 /dev/loop7
> crw-rw---- 1 root disk 10, 237 Aug 7 12:59 /dev/loop-control
> (cr) (feature/deb11-II) colin@M00974055-VM ~/chromiumos/src/scripts $
> sudo ls /dev/loop-control
> /dev/loop-control
>
>
> _________________________________________________________________
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