[dm-devel] [PATCH 6/7] multipath: delegate flushing maps to multipathd

[Benjamin Marzinski]

Since there can be problems with removing maps outside of multipathd,
multipath should attempt to delegate this command to multipathd.
However, multipathd doesn't attempt to suspend the device, in order
to avoid potential hangs. If delegating to multipathd fails, multipath
should try the remove itself.

Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
---
 multipath/main.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/multipath/main.c b/multipath/main.c
index 101fd656..6a24e483 100644
--- a/multipath/main.c
+++ b/multipath/main.c
@@ -820,6 +820,20 @@ int delegate_to_multipathd(enum mpath_cmds cmd,
 	if (cmd == CMD_CREATE && conf->force_reload == FORCE_RELOAD_YES) {
 		p += snprintf(p, n, "reconfigure");
 	}
+	else if (cmd == CMD_FLUSH_ONE && dev && dev_type == DEV_DEVMAP) {
+		p += snprintf(p, n, "del map %s", dev);
+		/* multipathd doesn't try as hard, to avoid potentially
+		 * hanging. If it fails, retry with the regular multipath
+		 * command */
+		r = NOT_DELEGATED;
+	}
+	else if (cmd == CMD_FLUSH_ALL) {
+		p += snprintf(p, n, "del maps");
+		/* multipathd doesn't try as hard, to avoid potentially
+		 * hanging. If it fails, retry with the regular multipath
+		 * command */
+		r = NOT_DELEGATED;
+	}
 	/* Add other translations here */
 
 	if (strlen(command) == 0)
-- 
2.17.2