From cab9c67d461c65a1138359f9f6d39636466b90e4 Mon Sep 17 00:00:00 2001
From: Blazej Kucman <blazej.kucman@intel.com>
Date: Wed, 9 Sep 2020 10:31:19 +0200
Subject: [PATCH 094/108] mdmonitor: set small delay once

If mdmonitor is awakened by event, set small delay once
to deal with udev and mdadm.

Signed-off-by: Blazej Kucman <blazej.kucman@intel.com>
Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>
---
 Monitor.c | 14 +++++++++++++-
 mdadm.h   |  2 +-
 mdstat.c  | 18 +++++++++++++++---
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/Monitor.c b/Monitor.c
index aed7a69..0fb4f77 100644
--- a/Monitor.c
+++ b/Monitor.c
@@ -128,6 +128,7 @@ int Monitor(struct mddev_dev *devlist,
 	char *mailfrom;
 	struct alert_info info;
 	struct mddev_ident *mdlist;
+	int delay_for_event = c->delay;
 
 	if (!mailaddr) {
 		mailaddr = conf_get_mailaddr();
@@ -249,7 +250,18 @@ int Monitor(struct mddev_dev *devlist,
 				break;
 			}
 			else {
-				mdstat_wait(c->delay);
+				int wait_result = mdstat_wait(delay_for_event);
+
+				/*
+				 * If mdmonitor is awaken by event, set small delay once
+				 * to deal with udev and mdadm.
+				 */
+				if (wait_result != 0) {
+					if (c->delay > 5)
+						delay_for_event = 5;
+				} else
+					delay_for_event = c->delay;
+
 				mdstat_close();
 			}
 		}
diff --git a/mdadm.h b/mdadm.h
index 399478b..4961c0f 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -628,7 +628,7 @@ struct mdstat_ent {
 extern struct mdstat_ent *mdstat_read(int hold, int start);
 extern void mdstat_close(void);
 extern void free_mdstat(struct mdstat_ent *ms);
-extern void mdstat_wait(int seconds);
+extern int mdstat_wait(int seconds);
 extern void mdstat_wait_fd(int fd, const sigset_t *sigmask);
 extern int mddev_busy(char *devnm);
 extern struct mdstat_ent *mdstat_by_component(char *name);
diff --git a/mdstat.c b/mdstat.c
index 48559e6..dd96cca 100644
--- a/mdstat.c
+++ b/mdstat.c
@@ -302,7 +302,17 @@ void mdstat_close(void)
 	mdstat_fd = -1;
 }
 
-void mdstat_wait(int seconds)
+/*
+ * function: mdstat_wait
+ * Description: Function waits for event on mdstat.
+ * Parameters:
+ *		seconds - timeout for waiting
+ * Returns:
+ *		> 0 - detected event
+ *		0 - timeout
+ *		< 0 - detected error
+ */
+int mdstat_wait(int seconds)
 {
 	fd_set fds;
 	struct timeval tm;
@@ -312,10 +322,12 @@ void mdstat_wait(int seconds)
 		FD_SET(mdstat_fd, &fds);
 		maxfd = mdstat_fd;
 	} else
-		return;
+		return -1;
+
 	tm.tv_sec = seconds;
 	tm.tv_usec = 0;
-	select(maxfd + 1, NULL, NULL, &fds, &tm);
+
+	return select(maxfd + 1, NULL, NULL, &fds, &tm);
 }
 
 void mdstat_wait_fd(int fd, const sigset_t *sigmask)
-- 
2.7.5