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lvm2/udev/10-dm.rules.in
Peter Rajnoha 60e9c014a2 Fix udev rules to handle spurious events properly.
We can use DM_UDEV_PRIMARY_SOURCE_FLAG to identify the spurious events
and use it as an indication that the device has already been activated before
(and hence we can find this property in udev database).

WARNING: This change requires udev startup script to preserve udev database
from initrd. All the information stored there during activation of devices
is important for the initial "udevadm trigger --action=add" call that is
used in udev startup script. If not done this way, udev startup script needs
to define DM_UDEV_PRIMARY_SOURCE_FLAG=1 property for any ADD events it uses.
2010-06-23 17:00:32 +00:00

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# Copyright (C) 2009 Red Hat, Inc. All rights reserved.
#
# This file is part of LVM2.
# Udev rules for device-mapper devices.
#
# These rules create a DM control node in /dev/(DM_DIR) directory.
# The rules also create nodes named dm-x (x is a number) in /dev
# directory and symlinks to these nodes with names given by
# the actual DM names. Some udev environment variables are set
# for use in later rules:
# DM_NAME - actual DM device's name
# DM_UUID - UUID set for DM device (blank if not specified)
# DM_SUSPENDED - suspended state of DM device (0 or 1)
# DM_UDEV_RULES_VSN - DM udev rules version
KERNEL=="device-mapper", NAME="(DM_DIR)/control"
SUBSYSTEM!="block", GOTO="dm_end"
KERNEL!="dm-[0-9]*", GOTO="dm_end"
# Set proper sbin path, /sbin has higher priority than /usr/sbin.
ENV{DM_SBIN_PATH}="/sbin"
TEST!="$env{DM_SBIN_PATH}/dmsetup", ENV{DM_SBIN_PATH}="/usr/sbin"
TEST!="$env{DM_SBIN_PATH}/dmsetup", GOTO="dm_end"
# Decode udev control flags and set environment variables appropriately.
# These flags are encoded in DM_COOKIE variable that was introduced in
# kernel version 2.6.31. Therefore, we can use this feature with
# kernels >= 2.6.31 only.
ENV{DM_COOKIE}=="?*", IMPORT{program}="$env{DM_SBIN_PATH}/dmsetup udevflags $env{DM_COOKIE}"
# Device created, major and minor number assigned - "add" event generated.
# Table loaded - no event generated.
# Device resumed (or renamed) - "change" event generated.
# Device removed - "remove" event generated.
#
# The dm-X nodes are always created, even on "add" event, we can't suppress
# that (the node is created even earlier with devtmpfs). All the symlinks
# (e.g. /dev/mapper) are created in right time after a device has its table
# loaded and is properly resumed. For this reason, direct use of dm-X nodes
# is not recommended.
ACTION!="add|change", GOTO="dm_end"
# There is no cookie set nor any flags encoded in events not originating
# in libdevmapper so we need to detect this and try to behave correctly.
# For such spurious events, regenerate all flags from current udev database content
# (this information would normally be inaccessible for spurious ADD and CHANGE events).
ENV{DM_UDEV_PRIMARY_SOURCE_FLAG}=="1", GOTO="dm_flags_done"
IMPORT{db}="DM_UDEV_DISABLE_DM_RULES_FLAG"
IMPORT{db}="DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG"
IMPORT{db}="DM_UDEV_DISABLE_DISK_RULES_FLAG"
IMPORT{db}="DM_UDEV_DISABLE_OTHER_RULES_FLAG"
IMPORT{db}="DM_UDEV_LOW_PRIORITY_FLAG"
IMPORT{db}="DM_UDEV_DISABLE_LIBRARY_FALLBACK_FLAG"
IMPORT{db}="DM_UDEV_PRIMARY_SOURCE_FLAG"
IMPORT{db}="DM_UDEV_FLAG7"
IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG0"
IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG1"
IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG2"
IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG3"
IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG4"
IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG5"
IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG6"
IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG7"
LABEL="dm_flags_done"
# Normally, we operate on "change" events. But when coldplugging, there's an
# "add" event present. We have to recognize this and do our actions in this
# particular situation, too. Also, we don't want the nodes to be created
# prematurely on "add" events while not coldplugging. We check
# DM_UDEV_PRIMARY_SOURCE_FLAG to see if the device was activated correctly
# before and if not, we ignore the "add" event totally. This way we can support
# udev triggers generating "add" events (e.g. "udevadm trigger --action=add" or
# "echo add > /sys/block/<dm_device>/uevent"). The trigger with "add" event is
# also used at boot to reevaluate udev rules for all existing devices activated
# before (e.g. in initrd). If udev is used in initrd, we require the udev init
# script to not remove the existing udev database so we can reuse the information
# stored at the time of device activation in the initrd.
ACTION=="add", ENV{DM_UDEV_PRIMARY_SOURCE_FLAG}!="1", GOTO="dm_disable"
# "dm" sysfs subdirectory is available in newer versions of DM
# only (kernels >= 2.6.29). We have to check for its existence
# and use dmsetup tool instead to get the DM name, uuid and
# suspended state if the "dm" subdirectory is not present.
# The "suspended" item was added even later (kernels >= 2.6.31),
# so we also have to call dmsetup if the kernel version used
# is in between these releases.
TEST=="dm", ENV{DM_NAME}="$attr{dm/name}", ENV{DM_UUID}="$attr{dm/uuid}", ENV{DM_SUSPENDED}="$attr{dm/suspended}"
TEST!="dm", IMPORT{program}="$env{DM_SBIN_PATH}/dmsetup info -j %M -m %m -c --nameprefixes --noheadings --rows -o name,uuid,suspended"
ENV{DM_SUSPENDED}!="?*", IMPORT{program}="$env{DM_SBIN_PATH}/dmsetup info -j %M -m %m -c --nameprefixes --noheadings --rows -o suspended"
# dmsetup tool provides suspended state information in textual
# form with values "Suspended"/"Active". We translate it to
# 0/1 respectively to be consistent with sysfs values.
ENV{DM_SUSPENDED}=="Active", ENV{DM_SUSPENDED}="0"
ENV{DM_SUSPENDED}=="Suspended", ENV{DM_SUSPENDED}="1"
# This variable provides a reliable way to check that device-mapper
# rules were installed. It means that all needed variables are set
# by these rules directly so there's no need to acquire them again
# later. Other rules can alternate the functionality based on this
# fact (e.g. fallback to rules that behave correctly even without
# these rules installed). It also provides versioning for any
# possible future changes.
ENV{DM_UDEV_RULES_VSN}="1"
ENV{DM_UDEV_DISABLE_DM_RULES_FLAG}!="1", ENV{DM_NAME}=="?*", SYMLINK+="(DM_DIR)/$env{DM_NAME}"
# We have to ignore further rule application for inappropriate events
# and devices. But still send the notification if cookie exists.
ENV{DM_UUID}=="mpath-?*", ENV{DM_ACTION}=="PATH_FAILED", GOTO="dm_disable"
ENV{DM_UUID}=="CRYPT-TEMP-?*", GOTO="dm_disable"
ENV{DM_UUID}!="?*", ENV{DM_NAME}=="temporary-cryptsetup-?*", GOTO="dm_disable"
GOTO="dm_end"
LABEL="dm_disable"
ENV{DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG}="1"
ENV{DM_UDEV_DISABLE_DISK_RULES_FLAG}="1"
ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}="1"
LABEL="dm_end"