Fix statechange-led.sh & unnecessary libdevmapper warning

- Fix autoreplace behaviour on statechange-led.sh script.

ZED sends the following events on an auto-replace:

1. statechange: Disk goes UNAVAIL->ONLINE
2. statechange: Disk goes ONLINE->UNAVAIL
3. vdev_attach: Disk goes ONLINE

Events 1-2 happen when ZED first attempts to do an auto-online.  When that
fails, ZED then tries an auto-replace, generating the vdev_attach event in #3.

In the previous code, statechange-led was only looking at the UNAVAIL->ONLINE
transition to turn off the LED.  It ignored the #2 ONLINE->UNAVAIL transition,
assuming it was just the "old" VDEV going offline.  This is problematic, as
a drive can go from ONLINE->UNAVAIL when it's malfunctioning, and we don't want
to ignore that.

This new patch correctly turns on the fault LED every time a drive becomes
UNAVAIL.  It also monitors vdev_attach events to trigger turning off the LED
when an auto-replaced disk comes online.

- Remove unnecessary libdevmapper warning with --with-config=kernel

This fixes an unnecessary libdevmapper warning when building
--with-config=kernel.  Kernel code does not use libdevmapper, so the warning
is not needed.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tony Hutter <[email protected]>
Closes #2375 
Closes #5312 
Closes #5331 

2 files changed, 4 insertions, 20 deletions

diff --git a/cmd/zed/zed.d/statechange-led.sh b/cmd/zed/zed.d/statechange-led.sh
index af1a14a9a..257e4a8a0 100755
--- a/cmd/zed/zed.d/statechange-led.sh
+++ b/cmd/zed/zed.d/statechange-led.sh
@@ -71,29 +71,12 @@ function led
 function process {
 	path="$1"
 	fault=$2
-	prev=$3
-	if [ "$fault" == "FAULTED" ] || [ "$fault" == "DEGRADED" ] ; then
-		led "$path" 1
-	elif [ "$fault" == "UNAVAIL" ] && [ "$prev" != "ONLINE" ] ; then
-		# For the most part, UNAVAIL should turn on the LED.  However,
-		# during an autoreplace, we see our new drive go online,
-		# followed by our "old" drive going ONLINE->UNAVAIL. Since the
-		# "old" drive has the same slot information, we want to ignore
-		# the ONLINE->UNAVAIL event.
-		#
-		# 	NAME             STATE     READ WRITE CKSUM
-		#	mypool3          DEGRADED     0     0     0
-		#	  mirror-0       DEGRADED     0     0     0
-		#	    A1           ONLINE       0     0     0
-		#	    A2           ONLINE       0   880     0
-		#	    replacing-3  UNAVAIL      0     0     0
-		#	      old        UNAVAIL      0 2.93K     0  corrupted data
-		#	      A3         ONLINE       0     0   156  (resilvering)
+	if [ "$fault" == "FAULTED" ] || [ "$fault" == "DEGRADED" ] || \
+	   [ "$fault" == "UNAVAIL" ] ; then
 		led "$path" 1
 	elif [ "$fault" == "ONLINE" ] ; then
 		led "$path" 0
 	fi
 }
 
-process "$ZEVENT_VDEV_ENC_SYSFS_PATH" "$ZEVENT_VDEV_STATE_STR" \
-    "$ZEVENT_VDEV_LASTSTATE_STR"
+process "$ZEVENT_VDEV_ENC_SYSFS_PATH" "$ZEVENT_VDEV_STATE_STR"
diff --git a/cmd/zed/zed.d/vdev_attach-led.sh b/cmd/zed/zed.d/vdev_attach-led.sh
new file mode 120000
index 000000000..7d7404398
--- /dev/null
+++ b/cmd/zed/zed.d/vdev_attach-led.sh
@@ -0,0 +1 @@
+statechange-led.sh
\ No newline at end of file