Mini Shell

# Copyright (C) 2012,2021 Red Hat, Inc. All rights reserved.
#
# This file is part of LVM.
#
# This rule requires blkid to be called on block devices before so only devices
# used as LVM PVs are processed (ID_FS_TYPE="LVM2_member").

SUBSYSTEM!="block", GOTO="lvm_end"


ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}=="1", GOTO="lvm_end"

# Ignore PVs on LVs.
# This is usually a case of an LV being used for a guest VM
# image, where the guest is using lvm.  The host should
# ignore lvm data from the guest and not attempt to scan or
# activate guest PVs/LVs.  (To enable functions in this file
# for PVs layered on LVs, set LVM_PVSCAN_ON_LVS="1" from a
# custom udev rule.)
ENV{ID_FS_TYPE}=="LVM2_member", ENV{DM_UUID}=="LVM-?*", ENV{LVM_PVSCAN_ON_LVS}!="1", GOTO="lvm_end"

# Only process devices already marked as a PV - this requires blkid to be called before.
ENV{ID_FS_TYPE}!="LVM2_member", GOTO="lvm_end"
ENV{DM_MULTIPATH_DEVICE_PATH}=="1", GOTO="lvm_end"
ACTION=="remove", GOTO="lvm_end"

# 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.
# Also support coldplugging with ADD event but only if the device is already
# properly activated.
# This logic should be eventually moved to rules where those particular
# devices are processed primarily (MD and loop).

# DM device:
KERNEL!="dm-[0-9]*", GOTO="next"
ENV{DM_UDEV_PRIMARY_SOURCE_FLAG}=="1", ENV{DM_ACTIVATION}=="1", GOTO="lvm_scan"
GOTO="lvm_end"

# MD device:
LABEL="next"
KERNEL!="md[0-9]*", GOTO="next"
IMPORT{db}="LVM_MD_PV_ACTIVATED"
ACTION=="add", ENV{LVM_MD_PV_ACTIVATED}=="1", GOTO="lvm_scan"
ACTION=="change", ENV{LVM_MD_PV_ACTIVATED}!="1", TEST=="md/array_state", ENV{LVM_MD_PV_ACTIVATED}="1", GOTO="lvm_scan"
ACTION=="add", KERNEL=="md[0-9]*p[0-9]*", GOTO="lvm_scan"
GOTO="lvm_end"

# Loop device:
LABEL="next"
KERNEL!="loop[0-9]*", GOTO="next"
ACTION=="add", ENV{LVM_LOOP_PV_ACTIVATED}=="1", GOTO="lvm_scan"
ACTION=="change", ENV{LVM_LOOP_PV_ACTIVATED}!="1", TEST=="loop/backing_file", ENV{LVM_LOOP_PV_ACTIVATED}="1", GOTO="lvm_scan"
GOTO="lvm_end"

LABEL="next"
ACTION!="add", GOTO="lvm_end"

LABEL="lvm_scan"

# pvscan will check if this device completes a VG,
# i.e. all PVs in the VG are now present with the
# arrival of this PV.  If so, it prints to stdout:
# LVM_VG_NAME_COMPLETE='foo'
#
# When the VG is complete it can be activated, so
# vgchange -aay <vgname> is run.  It is run via
# systemd since it can take longer to run than
# udev wants to block when processing rules.
# (if there are hundreds of LVs to activate,
# the vgchange can take many seconds.)
#
# pvscan only reads the single device specified,
# and uses temp files under /run/lvm to check if
# other PVs in the VG are present.
#
# If event_activation=0 in lvm.conf, this pvscan
# (using checkcomplete) will do nothing, so that
# no event-based autoactivation will be happen.
#
# TODO: adjust the output of vgchange -aay so that
# it's better suited to appearing in the journal.

IMPORT{program}="/usr/sbin/lvm pvscan --cache --listvg --checkcomplete --vgonline --autoactivation event --udevoutput --journal=output $env{DEVNAME}"
ENV{LVM_VG_NAME_COMPLETE}=="?*", RUN+="/usr/bin/systemd-run --no-block --property DefaultDependencies=no --unit lvm-activate-$env{LVM_VG_NAME_COMPLETE} /usr/sbin/lvm vgchange -aay --autoactivation event $env{LVM_VG_NAME_COMPLETE}"
GOTO="lvm_end"

LABEL="lvm_end"