When multipath reloads a device or fails or restores a path, the udev
rules disable LVM scanning, but since .DM_NOSCAN isn't set, blkid is
still run on the device. When multipath devices that are set to
queue_if_no_path lose all their paths at close to the same time, udev
workers can hang trying to run blkid. The blkid results shouldn't
change when multipathd is adding, removing, failing or reinstating
paths, aside from avoiding hanging udev processes, we're skipping
unnecessary work.
Hence, set .DM_NOSCAN if MPATH_UNCHANGED is set, to avoid blkid from
being called in 13-dm.rules.
Suggested-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
---
multipath/11-dm-mpath.rules.in | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/multipath/11-dm-mpath.rules.in b/multipath/11-dm-mpath.rules.in
index 79227be..a816edb 100644
--- a/multipath/11-dm-mpath.rules.in
+++ b/multipath/11-dm-mpath.rules.in
@@ -145,9 +145,11 @@ IMPORT{db}="ID_PART_GPT_AUTO_ROOT"
LABEL="import_end"
-# If MPATH_UNCHANGED is set, adapt DM_ACTIVATION.
+# If MPATH_UNCHANGED is set, adapt DM_ACTIVATION and DM_NOSCAN.
+# .DM_NOSCAN controls whether blkid will be run in 13-dm-disk.rules;
+# we don't want to do that if MPATH_UNCHANGED is 1.
ENV{MPATH_UNCHANGED}=="0", ENV{DM_ACTIVATION}="1"
-ENV{MPATH_UNCHANGED}=="1", ENV{DM_ACTIVATION}="0"
+ENV{MPATH_UNCHANGED}=="1", ENV{DM_ACTIVATION}="0", ENV{.DM_NOSCAN}="1"
# Reset previous DM_COLDPLUG_SUSPENDED if activation happens now
ENV{.DM_SUSPENDED}!="1", ENV{DM_ACTIVATION}=="1", ENV{DM_COLDPLUG_SUSPENDED}=""
--
2.47.0
