From 20a307c5981b0f256196a3b9b1e45c833bf5171b Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Fri, 14 Jan 2011 09:14:33 +1100
Subject: [PATCH] --- yaml --- r: 230646 b: refs/heads/master c:
 0ca69886a8273ac1350143d562280bfcbe4760dc h: refs/heads/master v: v3

---
 [refs]                | 2 +-
 trunk/drivers/md/md.c | 8 ++++++--
 trunk/drivers/md/md.h | 3 ++-
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index e3664ac0467c..ff628b4df49d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 067032bc628598606056412594042564fcf09e22
+refs/heads/master: 0ca69886a8273ac1350143d562280bfcbe4760dc
diff --git a/trunk/drivers/md/md.c b/trunk/drivers/md/md.c
index a3019121dc57..540347c538f9 100644
--- a/trunk/drivers/md/md.c
+++ b/trunk/drivers/md/md.c
@@ -288,10 +288,12 @@ static int md_make_request(struct request_queue *q, struct bio *bio)
 	int rv;
 	int cpu;
 
-	if (mddev == NULL || mddev->pers == NULL) {
+	if (mddev == NULL || mddev->pers == NULL
+	    || !mddev->ready) {
 		bio_io_error(bio);
 		return 0;
 	}
+	smp_rmb(); /* Ensure implications of  'active' are visible */
 	rcu_read_lock();
 	if (mddev->suspended) {
 		DEFINE_WAIT(__wait);
@@ -4564,7 +4566,8 @@ int md_run(mddev_t *mddev)
 	mddev->safemode_timer.data = (unsigned long) mddev;
 	mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
 	mddev->in_sync = 1;
-
+	smp_wmb();
+	mddev->ready = 1;
 	list_for_each_entry(rdev, &mddev->disks, same_set)
 		if (rdev->raid_disk >= 0) {
 			char nm[20];
@@ -4725,6 +4728,7 @@ EXPORT_SYMBOL_GPL(md_stop_writes);
 
 void md_stop(mddev_t *mddev)
 {
+	mddev->ready = 0;
 	mddev->pers->stop(mddev);
 	if (mddev->pers->sync_request && mddev->to_remove == NULL)
 		mddev->to_remove = &md_redundancy_group;
diff --git a/trunk/drivers/md/md.h b/trunk/drivers/md/md.h
index d05bab55df4e..229675a604f7 100644
--- a/trunk/drivers/md/md.h
+++ b/trunk/drivers/md/md.h
@@ -148,7 +148,8 @@ struct mddev_s
 						       * are happening, so run/
 						       * takeover/stop are not safe
 						       */
-
+	int				ready; /* See when safe to pass 
+						* IO requests down */
 	struct gendisk			*gendisk;
 
 	struct kobject			kobj;