Workaround broken VDEV_UPATH

Sometimes, for reasons I haven't looked into yet, VDEV_UPATH
gets set to /dev/(null), breaking all these scripts.

It'd be nice to have a fallback case to avoid total failure.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rich Ercolani <rincebrain@gmail.com>
Closes #13436

cmd/zpool/zpool.d/iostat

@@ -15,6 +15,15 @@ if [ "$1" = "-h" ] ; then
 	exit
 fi
 
+# Sometimes, UPATH ends up /dev/(null).
+# That should be corrected, but for now...
+# shellcheck disable=SC2154
+if [ ! -b "$VDEV_UPATH" ]; then
+	somepath="${VDEV_PATH}"
+else
+	somepath="${VDEV_UPATH}"
+fi
+
 if [ "$script" = "iostat-1s" ] ; then
 	# Do a single one-second sample
 	interval=1
@@ -27,8 +36,7 @@ elif [ "$script" = "iostat-10s" ] ; then
 	brief="yes"
 fi
 
-# shellcheck disable=SC2154
+if [ -f "$somepath" ] ; then
-if [ -f "$VDEV_UPATH" ] ; then
 	# We're a file-based vdev, iostat doesn't work on us.  Do nothing.
 	exit
 fi
@@ -37,13 +45,13 @@ if [ "$(uname)" = "FreeBSD" ]; then
 	out=$(iostat -dKx \
 		${interval:+"-w $interval"} \
 		${interval:+"-c 1"} \
-		"$VDEV_UPATH" | tail -n 2)
+		"$somepath" | tail -n 2)
 else
 	out=$(iostat -kx \
 		${brief:+"-y"} \
 		${interval:+"$interval"} \
 		${interval:+"1"} \
-		"$VDEV_UPATH" | grep -v '^$' | tail -n 2)
+		"$somepath" | grep -v '^$' | tail -n 2)
 fi
 
 

cmd/zpool/zpool.d/lsblk

@@ -61,21 +61,29 @@ else
 	list=$(echo "$script" | tr '[:upper:]' '[:lower:]')
 fi
 
+# Sometimes, UPATH ends up /dev/(null).
+# That should be corrected, but for now...
+# shellcheck disable=SC2154
+if [ ! -b "$VDEV_UPATH" ]; then
+	somepath="${VDEV_PATH}"
+else
+	somepath="${VDEV_UPATH}"
+fi
+
 # Older versions of lsblk don't support all these values (like SERIAL).
 for i in $list ; do
 
 	# Special case: Looking up the size of a file-based vdev can't
 	# be done with lsblk.
-	# shellcheck disable=SC2154
+	if [ "$i" = "size" ] && [ -f "$somepath" ] ; then
-	if [ "$i" = "size" ] && [ -f "$VDEV_UPATH" ] ; then
+		size=$(du -h --apparent-size "$somepath" | cut -f 1)
-		size=$(du -h --apparent-size "$VDEV_UPATH" | cut -f 1)
 		echo "size=$size"
 		continue
 	fi
 
 
 	val=""
-	if val=$(eval "lsblk -dl -n -o $i $VDEV_UPATH 2>/dev/null") ; then
+	if val=$(eval "lsblk -dl -n -o $i $somepath 2>/dev/null") ; then
 		# Remove leading/trailing whitespace from value
 		val=$(echo "$val" | sed -e 's/^[[:space:]]*//' \
 		     -e 's/[[:space:]]*$//')

cmd/zpool/zpool.d/smart

@@ -69,8 +69,16 @@ if [ "$1" = "-h" ] ; then
         exit
 fi
 
+# Sometimes, UPATH ends up /dev/(null).
+# That should be corrected, but for now...
 # shellcheck disable=SC2154
-if [ -b "$VDEV_UPATH" ] && PATH="/usr/sbin:$PATH" command -v smartctl > /dev/null || [ -n "$samples" ] ; then
+if [ ! -b "$VDEV_UPATH" ]; then
+	somepath="${VDEV_PATH}"
+else
+	somepath="${VDEV_UPATH}"
+fi
+
+if [ -b "$somepath" ] && PATH="/usr/sbin:$PATH" command -v smartctl > /dev/null || [ -n "$samples" ] ; then
 	if [ -n "$samples" ] ; then
 		# cat a smartctl output text file instead of running smartctl
 		# on a vdev (only used for developer testing).
@@ -78,7 +86,7 @@ if [ -b "$VDEV_UPATH" ] && PATH="/usr/sbin:$PATH" command -v smartctl > /dev/nul
 		echo "file=$file"
 		raw_out=$(cat "$samples/$file")
 	else
-		raw_out=$(sudo smartctl -a "$VDEV_UPATH")
+		raw_out=$(sudo smartctl -a "$somepath")
 	fi
 
 	# What kind of drive are we?  Look for the right line in smartctl: