mnt: Factor umount_mnt from umount_tree

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.

Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index e669a3bf86e7..010d5bebcb7e 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -822,6 +822,16 @@ static void detach_mnt(struct mount *mnt, struct path *old_path)
 /*
  * 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)
@@ -1371,9 +1381,7 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
                 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);
         }