This effectively reverts
4fc411f7a3ecee8a70fc8d6c687fae9a1cf20b31 (part of #6807) and
f6fbe25664629d1ae6a3b186f14ec69dbe6c6232 (#9042) ‒
the code itself and latter PR cite symmetry with whole-disk-vdev
behaviour (presumably because rootfs vdevs are rarely whole disks),
but the code is broken for NVME devices (indeed, it'd strip the
controller number instead of the (potential) partition number, turning
"nvme0n1p1" into "nvmen1p1", which would then subsequently fail the
sysfs existence check); it could be fixed to handle those (and any
others) rather easily by dereferencing /sys/class/block/$devname,
but this isn't the place for setting this ‒ as noted in the commit that
removed setting the scheduler by default
(9e17e6f2541c69a7a5e0ed814a7f5e71cbf8b90a) ‒ use an udev rule
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes#11838
aa5a4eb5d0