For kernel-generated path events, DM_NR_VALID_PATHS indicates
whether usable paths are available. But this information isn't
reliable as events may be received out of order.
Use multipath -U to determine whether a multipath map can
handle I/O.
Signed-off-by: Martin Wilck <mwilck@xxxxxxxx>
---
multipath/11-dm-mpath.rules | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/multipath/11-dm-mpath.rules b/multipath/11-dm-mpath.rules
index b131a103..d1ef85e5 100644
--- a/multipath/11-dm-mpath.rules
+++ b/multipath/11-dm-mpath.rules
@@ -18,8 +18,19 @@ ENV{DM_SUBSYSTEM_UDEV_FLAG2}=="1", ENV{MPATH_DEVICE_READY}="0",\
GOTO="mpath_action"
# If the last path has failed mark the device not ready
-ENV{DM_ACTION}=="PATH_FAILED", ENV{DM_NR_VALID_PATHS}=="0",\
- ENV{MPATH_DEVICE_READY}="0", GOTO="mpath_action"
+# Note that DM_NR_VALID_PATHS is only set for PATH_FAILED|PATH_REINSTATED
+# events.
+# This may not be reliable, as events aren't necessarily received in order.
+ENV{DM_NR_VALID_PATHS}=="0", ENV{MPATH_DEVICE_READY}="0", GOTO="mpath_action"
+
+ENV{MPATH_SBIN_PATH}="/sbin"
+TEST!="$env{MPATH_SBIN_PATH}/multipath", ENV{MPATH_SBIN_PATH}="/usr/sbin"
+
+# Check the map state directly with multipath -U.
+# This doesn't attempt I/O on the device.
+PROGRAM=="$env{MPATH_SBIN_PATH}/multipath -U %k", GOTO="paths_ok"
+ENV{MPATH_DEVICE_READY}="0", GOTO="mpath_action"
+LABEL="paths_ok"
# Don't mark a device ready on a PATH_FAILED event. even if
# DM_NR_VALID_PATHS is greater than 0. Just keep the existing
--
2.14.0
--
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