root@pve:/zfs# mount |grep -w $PWD
zfs on /zfs type zfs (rw,relatime,xattr,noacl,casesensitive)

root@pve:/zfs# cat /sys/module/zfs/parameters/zfs_bclone_enabled 
1

root@pve:/zfs# strace tar xf systemd.tar --reflink
execve("/usr/local/bin/tar", ["tar", "xf", "systemd.tar", "--reflink"], 0x7ffe2eb77ee8 /* 19 vars */) = 0
[...]
openat(AT_FDCWD, "systemd/sleep.conf", O_WRONLY|O_CREAT|O_EXCL|O_NOCTTY|O_NONBLOCK|O_CLOEXEC, 0600) = 4
ioctl(4, BTRFS_IOC_CLONE_RANGE or FICLONERANGE, {src_fd=3, src_offset=20480, src_length=4096, dest_offset=0}) = -1 EINVAL (Invalid argument)
read(3, "#  This file is part of systemd."..., 10240) = 10240
write(4, "#  This file is part of systemd."..., 953) = 953
utimensat(4, NULL, [UTIME_OMIT, {tv_sec=1706304939, tv_nsec=0} /* 2024-01-26T22:35:39+0100 */], 0) = 0
fchown(4, 0, 0)                         = 0
fchmod(4, 0644)                         = 0
close(4)                                = 0
openat(AT_FDCWD, "systemd/logind.conf", O_WRONLY|O_CREAT|O_EXCL|O_NOCTTY|O_NONBLOCK|O_CLOEXEC, 0600) = 4
ioctl(4, BTRFS_IOC_CLONE_RANGE or FICLONERANGE, {src_fd=3, src_offset=24576, src_length=4096, dest_offset=0}) = -1 EINVAL (Invalid argument)
write(4, "#  This file is part of systemd."..., 1539) = 1539
utimensat(4, NULL, [UTIME_OMIT, {tv_sec=1706305716, tv_nsec=0} /* 2024-01-26T22:48:36+0100 */], 0) = 0
fchown(4, 0, 0)                         = 0
fchmod(4, 0644)                         = 0
close(4)                                = 0
openat(AT_FDCWD, "systemd/networkd.conf", O_WRONLY|O_CREAT|O_EXCL|O_NOCTTY|O_NONBLOCK|O_CLOEXEC, 0600) = 4
ioctl(4, BTRFS_IOC_CLONE_RANGE or FICLONERANGE, {src_fd=3, src_offset=28672, src_length=4096, dest_offset=0}) = -1 EINVAL (Invalid argument)
write(4, "#  This file is part of systemd."..., 846) = 846
utimensat(4, NULL, [UTIME_OMIT, {tv_sec=1706304939, tv_nsec=0} /* 2024-01-26T22:35:39+0100 */], 0) = 0
fchown(4, 0, 0)                         = 0
fchmod(4, 0644)                         = 0
close(4)                                = 0