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lvm2/udev/69-dm-lvm-metad.rules.in
David Teigland d558b3ad7e vgchange -aay: optimize device scan using pvs_online files
Port the old pvscan -aay scanning optimization to vgchange -aay.
The optimization uses pvs_online files created by pvscan --cache
to derive a list of devices to use when activating a VG.  This
allows autoactivation of a VG to avoid scanning all devices, and
only scan the devices used by the VG itself.  The optimization is
applied internally using the device hints interface.

The new option "--autoactivation event" is given to pvscan and
vgchange commands that are called by event activation.  This
informs the command that it is being used for event activation,
so that it can apply checks and optimizations that are specific
to event activation.  Those include:

- skipping the command if lvm.conf event_activation=0
- checking that a VG is complete before activating it
- using pvs_online files to limit device scanning
2021-11-04 11:08:38 -05:00

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# Copyright (C) 2012 Red Hat, Inc. All rights reserved.
#
# This file is part of LVM2.
# Udev rules for 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" or "LVM1_member").
SUBSYSTEM!="block", GOTO="lvm_end"
(LVM_EXEC_RULE)
ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}=="1", GOTO="lvm_end"
# Detect removed PV label by comparing previous ID_FS_TYPE value with current one.
ENV{.ID_FS_TYPE_NEW}="$env{ID_FS_TYPE}"
IMPORT{db}="ID_FS_TYPE"
ENV{ID_FS_TYPE}=="LVM2_member|LVM1_member", ENV{.ID_FS_TYPE_NEW}!="LVM2_member|LVM1_member", ENV{LVM_PV_GONE}="1"
ENV{ID_FS_TYPE}="$env{.ID_FS_TYPE_NEW}"
ENV{LVM_PV_GONE}=="1", GOTO="lvm_scan"
# Only process devices already marked as a PV - this requires blkid to be called before.
ENV{ID_FS_TYPE}!="LVM2_member|LVM1_member", GOTO="lvm_end"
ENV{DM_MULTIPATH_DEVICE_PATH}=="1", GOTO="lvm_end"
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.
# 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"
ENV{LVM_MD_PV_ACTIVATED}!="1", ENV{SYSTEMD_READY}="0"
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"
ENV{LVM_LOOP_PV_ACTIVATED}!="1", ENV{SYSTEMD_READY}="0"
GOTO="lvm_end"
# If the PV is not a special device listed above, scan only if necessary.
# For "systemd_background" mode, systemd takes care of this by activating
# the lvm2-pvscan@.service only once.
LABEL="next"
ACTION!="(PVSCAN_ACTION)", GOTO="lvm_end"
LABEL="lvm_scan"
ENV{SYSTEMD_READY}="1"
# The method for invoking pvscan is selected at build time with the option
# --(enable|disable)-udev-systemd-background-jobs to "configure".
# On modern distributions with recent systemd, it's "systemd_background";
# on others, "direct_pvscan".
GOTO="(PVSCAN_RULE)"
LABEL="systemd_background"
# The table below summarises the situations in which we reach the LABEL="lvm_scan"
# in the "systemd_background" case.
# Marked by X, X* means only if the special dev is properly set up.
# The artificial ADD is supported for coldplugging. We avoid running the pvscan
# on artificial CHANGE so there's no unexpected autoactivation when WATCH rule fires.
# N.B. MD and loop never actually reaches lvm_scan on REMOVE as the PV label is gone
# within a CHANGE event (these are caught by the "LVM_PV_GONE" rule at the beginning).
#
# In this case, we simply set up the dependency between the device and the pvscan
# job using SYSTEMD_ALIAS (which sets up a simplified device identifier that
# allows using "BindsTo" in the sytemd unit file) and SYSTEMD_WANTS (which tells
# systemd to start the pvscan job once the device is ready).
# We need to set these variables for both "add" and "change" events, otherwise
# systemd may loose information about the device/unit dependencies.
#
# | real ADD | real CHANGE | artificial ADD | artificial CHANGE | REMOVE
# =============================================================================
# DM | | X | X* | | X
# MD | | X | X* | |
# loop | | X | X* | |
# other | X | X | X | | X
ACTION!="remove", ENV{LVM_PV_GONE}=="1", RUN+="(BINDIR)/systemd-run (LVM_EXEC)/lvm pvscan --cache $major:$minor", GOTO="lvm_end"
ENV{SYSTEMD_ALIAS}="/dev/block/$major:$minor"
ENV{SYSTEMD_WANTS}+="lvm2-pvscan@$major:$minor.service"
GOTO="lvm_end"
# FIXME: this mode is not used and should be removed.
LABEL="direct_pvscan"
# The table below summarises the situations in which we reach the LABEL="lvm_scan"
# for the "direct_pvscan" case.
# Marked by X, X* means only if the special dev is properly set up.
# The artificial ADD is supported for coldplugging. We avoid running the pvscan
# on artificial CHANGE so there's no unexpected autoactivation when WATCH rule fires.
#
# In this case, we need to make sure that pvscan is not invoked spuriously, therefore
# we invoke it only for "add" events for "other" devices.
#
# | real ADD | real CHANGE | artificial ADD | artificial CHANGE | REMOVE
# =============================================================================
# DM | | X | X* | | X
# MD | | X | X* | |
# loop | | X | X* | |
# other | X | | X | | X
RUN+="(LVM_EXEC)/lvm pvscan --cache --aay --autoactivation event --major $major --minor $minor", ENV{LVM_SCANNED}="1"
LABEL="lvm_end"