udev: create /dev/disk/by-id/lvm-pv-uuid-<PV_UUID> symlink for a PV

We already have /dev/disk/by-id/dm-uuid-... (which encompasses the
VG UUID and LV UUID in case of LVs since the mapping's UUID is
VG+LV UUID together) and /dev/disk/by-id/dm-name-... (which encompasses
the VG and LV name in case of LVs).

This patch addds /dev/disk/by-id/lvm-pv-uuid-<PV_UUID> that completes
this scheme and makes navigation a bit easier using PV UUIDs since
one can navigate using PV UUIDs only and there's no need to do extra
PV UUID <--> kernel name matching (the PV UUID is stable across reboots).
This may come in handy in various scripts.

Since we already have the PV UUID stored in udev database (as a result
of blkid call - returned in ID_FS_UUID blkid's variable), this operation
is very cheap indeed, just creating the extra one symlink.

1 files changed, 3 insertions, 0 deletions

diff --git a/udev/69-dm-lvm-metad.rules.in b/udev/69-dm-lvm-metad.rules.in
index e8304b5e0..bd75fc8ef 100644
--- a/udev/69-dm-lvm-metad.rules.in
+++ b/udev/69-dm-lvm-metad.rules.in
@@ -34,6 +34,9 @@ ENV{DM_MULTIPATH_DEVICE_PATH}=="1", GOTO="lvm_end"
 # Inform lvmetad about any PV that is gone.
 ACTION=="remove", GOTO="lvm_scan"
 
+# Create /dev/disk/by-id/lvm-pv-uuid-<PV_UUID> symlink for each PV
+ENV{ID_FS_UUID_ENC}=="?*", SYMLINK+="disk/by-id/lvm-pv-uuid-$env{ID_FS_UUID_ENC}"
+
 # If the PV is a special device listed below, scan only if the device is
 # properly activated. These devices are not usable after an ADD event,
 # but they require an extra setup and they are ready after a CHANGE event.