Comment 3 for bug 1755999

A quick and dirty gdb debug indicates it's looping with copy_file_range syscall(326)

$ grep copy /usr/include/asm/unistd_64.h
#define __NR_copy_file_range 326

gdb --args /usr/sbin/xfs_io -i -f -c "copy_range -s 4000 -l 2000 /home/ubuntu/test/test-430/file" "/home/ubuntu/test/test-430/beyond"

(gdb) catch syscall 326
Catchpoint 1 (syscall 326)
(gdb) run
Starting program: /usr/sbin/xfs_io -i -f -c copy_range\ -s\ 4000\ -l\ 2000\ /home/ubuntu/test/test-430/file /home/ubuntu/test/test-430/beyond
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7ffff7036700 (LWP 10450)]

Thread 1 "xfs_io" hit Catchpoint 1 (call to syscall 326), syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
38 ../sysdeps/unix/sysv/linux/x86_64/syscall.S: No such file or directory.
(gdb) continue
Continuing.

Thread 1 "xfs_io" hit Catchpoint 1 (returned from syscall 326), syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
38 in ../sysdeps/unix/sysv/linux/x86_64/syscall.S
(gdb) continue
Continuing.

Thread 1 "xfs_io" hit Catchpoint 1 (call to syscall 326), syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
38 in ../sysdeps/unix/sysv/linux/x86_64/syscall.S
(gdb) continue
Continuing.

Thread 1 "xfs_io" hit Catchpoint 1 (returned from syscall 326), syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
38 in ../sysdeps/unix/sysv/linux/x86_64/syscall.S
(gdb) continue
Continuing.

Thread 1 "xfs_io" hit Catchpoint 1 (call to syscall 326), syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
38 in ../sysdeps/unix/sysv/linux/x86_64/syscall.S
(gdb) continue
Continuing.