list_zvols() would happily, for zvols with spaces in their names,
assign the second half to volmode, &c., so use a normal read
and set IFS to a tab instead of using 4 separate AWK processes(?)
Similarly, in filter_out_deleted_zvols(), run zfs(8) once and use the
output directly instead of spawning a zfs(8) process per zvol
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes#11859
519aec83f5