[systemd-devel] [PATCH] udev rules: add by-location symlinks to nvme devices

[Charles.Rose at dell.com]

On systems with multiple 2.5-inch form factor PCIe SSD devices, locating the
physical drive can be made easier with symlinks in /dev/disk/by-location.

This rule reads the bay and slot information for each nvme device and creates
symlinks like this:

/dev/disk/by-location/pcie-ssd-in-slot-9-bay-1-nvme0n1 -> ../../nvme0n1
/dev/disk/by-location/pcie-ssd-in-slot-9-bay-1-nvme1n1 -> ../../nvme1n1
/dev/disk/by-location/pcie-ssd-in-slot-9-bay-1-nvme1n2 -> ../../nvme1n2
/dev/disk/by-location/pcie-ssd-in-slot-5-bay-1-nvme2n1 -> ../../nvme2n1

The bay/slot information is read from the sysfs label attribute available for
each pci device.

The label attribute is a OEM populated string. Systems from Dell contain Slot
and Bay information for NVMe devices. Other OEMs might do something similar,
there is no convention for the format at this time - hence the dmi check.

Signed-off-by: Charles Rose <charles.rose at dell.com>
---
 rules/61-nvme-location.rules | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 rules/61-nvme-location.rules

diff --git a/rules/61-nvme-location.rules b/rules/61-nvme-location.rules
new file mode 100644
index 000000000..296bad2e4
--- /dev/null
+++ b/rules/61-nvme-location.rules
@@ -0,0 +1,8 @@
+# Symlink NVMe Bay and Slot
+
+# Tested on Dell PowerEdge Servers.
+ATTR{[dmi/id]sys_vendor}!="Dell*", GOTO="nvme_location_end"
+
+KERNEL=="nvme*[0-9]n*[0-9]", ENV{DEVTYPE}=="disk", DRIVERS=="nvme", ATTRS{label}=="?*", PROGRAM="/bin/sh -c 'echo $attr{label} | tr [:blank:] - | tr [:upper:] [:lower:]'", SYMLINK+="disk/by-location/%c-%k"
+
+LABEL="nvme_location_end"
-- 
2.13.6