Comment 13 for bug 1969247

Impish kernel on zfs:

andreas@nsnx:~$ rm foo.img
andreas@nsnx:~$ touch foo.img
andreas@nsnx:~$ fallocate -z -l 10M foo.img
fallocate: fallocate failed: Operation not supported

Jammy kernel on zfs:

root@j1:~# touch foo.img
root@j1:~# fallocate -z -l 10M foo.img
root@j1:~# ll foo.img
-rw-r--r-- 1 root root 0 Apr 18 18:06 foo.img

Jammy kernel on ext4:

andreas@nsn7:~$ touch foo.img
andreas@nsn7:~$ fallocate -z -l 10M foo.img
andreas@nsn7:~$ l foo.img
-rw-rw-r-- 1 andreas andreas 10M abr 19 09:32 foo.img
andreas@nsn7:~$