releases/4.0.2/mnt-factor-umount_mnt-from-umount_tree.patch

From 6a46c5735c29175da55b2fa9d53775182422cdd7 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Thu, 15 Jan 2015 22:58:33 -0600
Subject: mnt: Factor umount_mnt from umount_tree

From: "Eric W. Biederman" <ebiederm@xmission.com>

commit 6a46c5735c29175da55b2fa9d53775182422cdd7 upstream.

For future use factor out a function umount_mnt from umount_tree.
This function unhashes a mount and remembers where the mount
was mounted so that eventually when the code makes it to a
sleeping context the mountpoint can be dput.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/namespace.c |   14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -822,6 +822,16 @@ static void detach_mnt(struct mount *mnt
 /*
  * vfsmount lock must be held for write
  */
+static void umount_mnt(struct mount *mnt)
+{
+	/* old mountpoint will be dropped when we can do that */
+	mnt->mnt_ex_mountpoint = mnt->mnt_mountpoint;
+	unhash_mnt(mnt);
+}
+
+/*
+ * vfsmount lock must be held for write
+ */
 void mnt_set_mountpoint(struct mount *mnt,
 			struct mountpoint *mp,
 			struct mount *child_mnt)
@@ -1373,9 +1383,7 @@ static void umount_tree(struct mount *mn
 		pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt, &unmounted);
 		if (mnt_has_parent(p)) {
 			mnt_add_count(p->mnt_parent, -1);
-			/* old mountpoint will be dropped when we can do that */
-			p->mnt_ex_mountpoint = p->mnt_mountpoint;
-			unhash_mnt(p);
+			umount_mnt(p);
 		}
 		change_mnt_propagation(p, MS_PRIVATE);
 	}