From 41f7723e9cb260f313f99d667142e37617812fca Mon Sep 17 00:00:00 2001
From: Simon Guest <simon.guest@tesujimath.org>
Date: Thu, 21 Dec 2017 06:42:07 +1300
Subject: [PATCH] vdev_id: new slot type ses

This extends vdev_id to support a new slot type, ses, for SCSI Enclosure
Services.  With slot type ses, the disk slot numbers are determined by
using the device slot number reported by sg_ses for the device with
matching SAS address, found by querying all available enclosures.

This is primarily of use on systems with a deficient driver omitting
support for bay_identifier in /sys/devices.  In my testing, I found that
the existing slot types of port and id were not stable across disk
replacement, so an alternative was required.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Simon Guest <simon.guest@tesujimath.org>
Closes #6956
---
 cmd/vdev_id/vdev_id     | 17 +++++++++++++++++
 man/man5/vdev_id.conf.5 |  8 +++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/cmd/vdev_id/vdev_id b/cmd/vdev_id/vdev_id
index 9fa2d672c0..4c7b270a85 100755
--- a/cmd/vdev_id/vdev_id
+++ b/cmd/vdev_id/vdev_id
@@ -276,6 +276,23 @@ sas_handler() {
 		d=$(eval echo \${$i})
 		SLOT=`echo $d | sed -e 's/^.*://'`
 		;;
+	"ses")
+		# look for this SAS path in all SCSI Enclosure Services
+		# (SES) enclosures
+		sas_address=`cat $end_device_dir/sas_address 2>/dev/null`
+		enclosures=`lsscsi -g | \
+			sed -n -e '/enclosu/s/^.* \([^ ][^ ]*\) *$/\1/p'`
+		for enclosure in $enclosures; do
+			set -- $(sg_ses -p aes $enclosure | \
+				awk "/device slot number:/{slot=\$12} \
+					/SAS address: $sas_address/\
+					{print slot}")
+			SLOT=$1
+			if [ -n "$SLOT" ] ; then
+				break
+			fi
+		done
+		;;
 	esac
 	if [ -z "$SLOT" ] ; then
 		return
diff --git a/man/man5/vdev_id.conf.5 b/man/man5/vdev_id.conf.5
index eff8c27cc4..50caa92c04 100644
--- a/man/man5/vdev_id.conf.5
+++ b/man/man5/vdev_id.conf.5
@@ -90,7 +90,7 @@ internally uses this value to determine which HBA or switch port a
 device is connected to.  The default is 4.
 
 .TP
-\fIslot\fR <bay|phy|port|id|lun>
+\fIslot\fR <bay|phy|port|id|lun|ses>
 Specifies from which element of a SAS identifier the slot number is
 taken.  The default is bay.
 
@@ -103,6 +103,12 @@ taken.  The default is bay.
 \fIid\fR - use the scsi id as the slot number.
 
 \fIlun\fR - use the scsi lun as the slot number.
+
+\fIses\fR - use the SCSI Enclosure Services (SES) enclosure device slot number,
+as reported by
+.BR sg_ses (8).
+This is intended for use only on systems where \fIbay\fR is unsupported,
+noting that \fIport\fR and \fIid\fR may be unstable across disk replacement.
 .SH EXAMPLES
 A non-multipath configuration with direct-attached SAS enclosures and an
 arbitrary slot re-mapping.