Several changes to udev support code:

 - we have these levels when the udev rules are processed:
   10-dm.rules --> [11-dm-<subsystem>.rules] --> [12-dm-permissions.rules] -->
   13-dm-disk.rules --> [...all the other foreign rules...] --> 95-dm-notify.rules

 - each level can be disabled now by
   DM_UDEV_DISABLE_{DM, SUBSYSTEM, DISK, OTHER}_RULES_FLAG

 - add DM_UDEV_DISABLE_DM_RULES_FLAG to disable 10-dm.rules

 - add DM_UDEV_DISABLE_OTHER_RULES_FLAG to disable all the other (non-dm) rules.
   We cutoff these rules by using the 'last_rule', so this one should really be
   used with great care and in well-founded situations. We use this for lvm's
   hidden and layer devices now.

 - add a parameter for add_dev_node, rm_dev_node and rename_dev_node so it's
   possible to switch on/off udev checks

 - use DM_UDEV_DISABLE_DM_RULES_FLAG and DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG
   if there's no cookie set and we have resume, remove and rename ioctl.
   This could happen when someone uses the libdevmapper that is compiled with
   udev_sync but the software does not make use of it. This way we can switch
   off the rules and fallback to libdevmapper node creation so there's no
   udev/libdevmapper race.

4 files changed, 31 insertions, 13 deletions

diff --git a/udev/10-dm.rules.in b/udev/10-dm.rules.in
index 211c0c31a..9c2e25680 100644
--- a/udev/10-dm.rules.in
+++ b/udev/10-dm.rules.in
@@ -21,8 +21,16 @@ 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}"
 
+# Normally, we would test for DM_UDEV_DISABLE_DM_RULES_FLAG here and skip
+# the rules if set. However, we need to set DM_* environment variables
+# for now to properly filter out inappropriate events. This dependency
+# might be removed in the future.
+
 ACTION!="add|change", GOTO="dm_end"
 
 # Normally, we operate on "change" events only. But when
@@ -58,18 +66,19 @@ ENV{DM_SUSPENDED}=="Suspended", ENV{DM_SUSPENDED}="1"
 # possible future changes.
 ENV{DM_UDEV_RULES_VSN}="1"
 
-ENV{DM_NAME}=="?*", SYMLINK+="(DM_DIR)/$env{DM_NAME}"
+ENV{DM_UDEV_DISABLE_DM_RULES_FLAG}!="1", ENV{DM_NAME}=="?*", SYMLINK+="(DM_DIR)/$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_last_rule"
-ENV{DM_UUID}=="CRYPT-TEMP-?*", GOTO="dm_last_rule"
-ENV{DM_UUID}!="?*", ENV{DM_NAME}=="temporary-cryptsetup-?*", GOTO="dm_last_rule"
+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_last_rule"
-ENV{DM_COOKIE}=="?*", RUN+="$env{DM_SBIN_PATH}/dmsetup udevcomplete $env{DM_COOKIE}"
-OPTIONS+="last_rule"
+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"
diff --git a/udev/11-dm-lvm.rules b/udev/11-dm-lvm.rules
index bcec09502..674a7de52 100644
--- a/udev/11-dm-lvm.rules
+++ b/udev/11-dm-lvm.rules
@@ -17,7 +17,7 @@ ENV{DM_UDEV_DISABLE_SUBSYSTEM_RULES_FLAG}=="1", GOTO="lvm_end"
 # Use DM name and split it up into its VG/LV/layer constituents.
 IMPORT{program}="$env{DM_SBIN_PATH}/dmsetup splitname --nameprefixes --noheadings --rows $env{DM_NAME}"
 
-# Do not create symlinks for hidden subdevices.
+# Do not create symlinks for inappropriate subdevices.
 ENV{DM_LV_NAME}=="?*_mimage_[0-9]*|pvmove?*|?*_vorigin", GOTO="lvm_end"
 
 # Create symlinks for top-level devices only.
diff --git a/udev/13-dm-disk.rules b/udev/13-dm-disk.rules
index 16a6edd25..94250ddf6 100644
--- a/udev/13-dm-disk.rules
+++ b/udev/13-dm-disk.rules
@@ -7,17 +7,26 @@
 
 # "add" event is processed on coldplug only!
 ACTION!="add|change", GOTO="dm_end"
-ENV{DM_UDEV_RULES_VSN}!="?*", GOTO="dm_end"
-ENV{DM_UDEV_DISABLE_DISK_RULES_FLAG}=="1", GOTO="dm_end"
+ENV{DM_UDEV_RULES_VSN}!="?*", GOTO="dm_other"
+ENV{DM_UDEV_DISABLE_DISK_RULES_FLAG}=="1", GOTO="dm_other"
 
 SYMLINK+="disk/by-id/dm-name-$env{DM_NAME}"
 ENV{DM_UUID}=="?*", SYMLINK+="disk/by-id/dm-uuid-$env{DM_UUID}"
 
-ENV{DM_SUSPENDED}=="1", GOTO="dm_end"
+ENV{DM_SUSPENDED}=="1", GOTO="dm_other"
 
 IMPORT{program}="$env{DM_SBIN_PATH}/blkid -o udev -p $tempnode"
 ENV{DM_UDEV_LOW_PRIORITY_FLAG}=="1", OPTIONS="link_priority=-100"
 ENV{ID_FS_USAGE}=="filesystem|other|crypto", ENV{ID_FS_UUID_ENC}=="?*", SYMLINK+="disk/by-uuid/$env{ID_FS_UUID_ENC}"
 ENV{ID_FS_USAGE}=="filesystem|other", ENV{ID_FS_LABEL_ENC}=="?*", SYMLINK+="disk/by-label/$env{ID_FS_LABEL_ENC}"
 
+# Cutoff all subsequent rules if instructed by a flag.
+# This flag should be used in well-founded situations only to prevent
+# any problems that could arise when processing this event further by
+# foreign rules (various temporary and hidden devices mostly).
+LABEL="dm_other"
+ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}!="1", GOTO="dm_end"
+ENV{DM_COOKIE}=="?*", RUN+="$env{DM_SBIN_PATH}/dmsetup udevcomplete $env{DM_COOKIE}"
+OPTIONS+="last_rule"
+
 LABEL="dm_end"
diff --git a/udev/Makefile.in b/udev/Makefile.in
index 341479f03..0a0050af3 100644
--- a/udev/Makefile.in
+++ b/udev/Makefile.in
@@ -16,8 +16,8 @@ top_srcdir = @top_srcdir@
 top_builddir = @top_builddir@
 VPATH = @srcdir@
 
-DM_RULES=10-dm.rules 12-dm-disk.rules 95-dm-notify.rules
-LVM_RULES=11-lvm.rules
+DM_RULES=10-dm.rules 13-dm-disk.rules 95-dm-notify.rules
+LVM_RULES=11-dm-lvm.rules
 DM_DIR=$(shell grep "\#define DM_DIR" $(top_srcdir)/libdm/misc/dm-ioctl.h | awk '{print $$3}')
 
 CLEAN_TARGETS=10-dm.rules