From 8af0717122c679b10bfe7734b9dcc3a61355018f Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Wed, 9 Jun 2010 15:31:01 +0200
Subject: [PATCH] --- yaml --- r: 200622 b: refs/heads/master c:
 29cb48594b873f6193d6327097e504bd3e2314de h: refs/heads/master v: v3

---
 [refs]                  |  2 +-
 trunk/fs/fs-writeback.c | 18 ++++++++++--------
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/[refs] b/[refs]
index 1b6da6984a9f..c1f07c5943a0 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 334132ae921a14ac2b2ba48e174136f7f2c9aae1
+refs/heads/master: 29cb48594b873f6193d6327097e504bd3e2314de
diff --git a/trunk/fs/fs-writeback.c b/trunk/fs/fs-writeback.c
index 3a066e91ec8d..0609607d3955 100644
--- a/trunk/fs/fs-writeback.c
+++ b/trunk/fs/fs-writeback.c
@@ -534,19 +534,21 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
 static bool pin_sb_for_writeback(struct super_block *sb)
 {
 	spin_lock(&sb_lock);
+	if (list_empty(&sb->s_instances)) {
+		spin_unlock(&sb_lock);
+		return false;
+	}
+
 	sb->s_count++;
+	spin_unlock(&sb_lock);
+
 	if (down_read_trylock(&sb->s_umount)) {
-		if (sb->s_root) {
-			spin_unlock(&sb_lock);
+		if (sb->s_root)
 			return true;
-		}
-		/*
-		 * umounted, drop rwsem again and fall through to failure
-		 */
 		up_read(&sb->s_umount);
 	}
-	sb->s_count--;
-	spin_unlock(&sb_lock);
+
+	put_super(sb);
 	return false;
 }