From 17868220a4b521ff00f5bbaef8a80e3c1a71ab11 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Tue, 20 Jul 2010 15:18:07 -0700
Subject: [PATCH] --- yaml --- r: 207599 b: refs/heads/master c:
 4f331f01b9c43bf001d3ffee578a97a1e0633eac h: refs/heads/master i:   207597:
 457c837fcc82d0049117f2548246c18218d6da53   207595:
 308051d11b1435e15e095ce7dc5c6aa1af24b1fe   207591:
 caebb839ad1c276bfffd9ef824a4d178770165c3   207583:
 42f16519a2282031d349e085ab8f6c4cfaba5ba4 v: v3

---
 [refs]           | 2 +-
 trunk/fs/super.c | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index c226af5e99d0..077ff48580da 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 719f2c879f4dda7d7f303bd387d37cd96db29d31
+refs/heads/master: 4f331f01b9c43bf001d3ffee578a97a1e0633eac
diff --git a/trunk/fs/super.c b/trunk/fs/super.c
index 938119ab8dcb..3479ca6f005f 100644
--- a/trunk/fs/super.c
+++ b/trunk/fs/super.c
@@ -773,7 +773,16 @@ int get_sb_bdev(struct file_system_type *fs_type,
 			goto error_bdev;
 		}
 
+		/*
+		 * s_umount nests inside bd_mutex during
+		 * __invalidate_device().  close_bdev_exclusive()
+		 * acquires bd_mutex and can't be called under
+		 * s_umount.  Drop s_umount temporarily.  This is safe
+		 * as we're holding an active reference.
+		 */
+		up_write(&s->s_umount);
 		close_bdev_exclusive(bdev, mode);
+		down_write(&s->s_umount);
 	} else {
 		char b[BDEVNAME_SIZE];