ext4 discard writeback

# data=writeback
root@debian64:~# dmesg |grep EXT4
[    0.299135] EXT4-fs (vda1): mounted filesystem with writeback data mode. Opts: (null)
[    0.516813] EXT4-fs (vda1): re-mounted. Opts: discard
root@debian64:~# time rm -rf linux-5.10

real    0m3.736s
user    0m0.078s
sys     0m0.830s
root@debian64:~# tar xf linux-5.10.tar.xz ; sync
root@debian64:~# mount / -oremount,nodiscard
[ 1931.165795] EXT4-fs (vda1): re-mounted. Opts: discard,nodiscard
root@debian64:~# time rm -rf linux-5.10

real    0m0.424s
user    0m0.040s
sys     0m0.385s

# data=ordered
root@debian64:~# dmesg |grep EXT4
[    0.245088] EXT4-fs (vda1): mounted filesystem with ordered data mode. Opts: (null)
[    0.436585] EXT4-fs (vda1): re-mounted. Opts: discard
root@debian64:~# tar xf linux-5.10.tar.xz ; sync
root@debian64:~# time rm -rf linux-5.10

real    0m0.550s
user    0m0.061s
sys     0m0.393s
root@debian64:~# mount / -oremount,nodiscard
[   43.612304] EXT4-fs (vda1): re-mounted. Opts: discard,nodiscard
root@debian64:~# tar xf linux-5.10.tar.xz ; sync
root@debian64:~# time rm -rf linux-5.10

real    0m0.451s
user    0m0.010s
sys     0m0.421s
root@debian64:~#