zfs: merge openzfs/zfs@8f1b7a6fa

zfs: merge openzfs/zfs@8f1b7a6fa

Notable upstream pull request merges:
 #15839 c3f2f1aa2 vdev probe to slow disk can stall mmp write checker
 #15888 5044c4e3f Fast Dedup: ZAP Shrinking
 #15996 db499e68f Overflowing refreservation is bad
 #16118 67d13998b Make more taskq parameters writable
 #16128 21bc066ec Fix updating the zvol_htable when renaming a zvol
 #16130 645b83307 Improve write issue taskqs utilization
 #16131 8fd3a5d02 Slightly improve dnode hash
 #16134 a6edc0adb zio: try to execute TYPE_NULL ZIOs on the current task
 #16141 b28461b7c Fix arcstats for FreeBSD after zfetch support

Obtained from:	OpenZFS
OpenZFS commit:	8f1b7a6fa6762ea4c89198ceb11c521f80b92ddc