Detect and enable trim for usb-connected sata/nvme drives in initramfs/initrd, ideally before zfs modules load.

usbtrim

#!/bin/bash 
# This goes in /usr/share/initramfs-tools/hooks/usbtrim
  
case $1 in
prereqs)
        echo "udev"
        exit 0
        ;;
esac

. /usr/share/initramfs-tools/hook-functions

mkdir -p $DESTDIR/lib/udev/rules.d/
testscsi=$(for devlink in /dev/disk/by-id/scsi*; do readlink -f "${devlink}" | sed 's/.*sd//'| cut -c1; done | sort -u)
[[ "$testscsi" == "/" ]] && test="" || test+="${testscsi} "
testata=$(for devlink in /dev/disk/by-id/ata*; do readlink -f "${devlink}" | sed 's/.*sd//'| cut -c1; done | sort -u)
[[ "$testata" == "/" ]] && test+="" || test+="${testata} "
testusb=$(for devlink in /dev/disk/by-id/usb*; do readlink -f "${devlink}" | sed 's/.*sd//'| cut -c1; done | sort -u)
[[ "$testusb" == "/" ]] && test+="" || test+="${testusb} "

[[ "$test" == "/" ]] && exit 0
[[ -z "$test" ]] && exit 0
for disk in $test; do
echo "checking sd${disk} for TRIM support."
if (sg_readcap -l /dev/sd"${disk}" | grep -q lbpme=0) ; then
   echo "Trim not detected by kernel on /dev/sd${disk}."
   if (sg_vpd -a /dev/sd"${disk}" | grep -q "(LBPU): 1") ; then
	echo "UAS trim available on /dev/sd${disk}."
	grep -q -s Created /etc/udev/rules.d/10-usb-trim.rules || (echo "# Created by `basename \"$0\"` in `dirname \"$0\"`" | tee /etc/udev/rules.d/10-usb-trim.rules)
	grep -q -s Created $DESTDIR/lib/udev/rules.d/10-usb-trim.rules || (echo "# Created by `basename \"$0\"` in `dirname \"$0\"`" | tee $DESTDIR/lib/udev/rules.d/10-usb-trim.rules)
	idVendor=$(lsusb -D $(udevadm info --path $(udevadm info -q path /dev/sd"${disk}" | rev | cut -d'/' -f7- | rev) | grep DEVNAME | cut -d = -f 2) 2>/dev/null | grep idVendor | awk '{print $2}' | cut -c 3-)
	idProduct=$(lsusb -D $(udevadm info --path $(udevadm info -q path /dev/sd"${disk}" | rev | cut -d'/' -f7- | rev) | grep DEVNAME | cut -d = -f 2) 2>/dev/null | grep idProduct | awk '{print $2}' | cut -c 3-)
	echo "ACTION==\"add|change\", ATTRS{idVendor}==\"$idVendor\", ATTRS{idProduct}==\"$idProduct\", SUBSYSTEM==\"scsi_disk\", ATTR{provisioning_mode}=\"unmap\"" | tee -a /etc/udev/rules.d/10-usb-trim.rules
	echo "ACTION==\"add|change\", ATTRS{idVendor}==\"$idVendor\", ATTRS{idProduct}==\"$idProduct\", SUBSYSTEM==\"scsi_disk\", ATTR{provisioning_mode}=\"unmap\"" | tee -a $DESTDIR/lib/udev/rules.d/10-usb-trim.rules
       if grep -q full /sys/block/sd"${disk}"/device/scsi_disk/*/provisioning_mode; then
           echo "full on /dev/sd${disk}."
        elif grep -q unmap /sys/block/sd"${disk}"/device/scsi_disk/*/provisioning_mode; then
           echo "unmap already set on /dev/sd${disk}."
        else 
           echo "enabling TRIM on /dev/sd${disk}."
           echo "unmap" | tee /sys/block/sd"${disk}"/device/scsi_disk/*/provisioning_mode
        fi
    fi
fi
done