3 files changed, 12 insertions, 3 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 25c1dcf9e9eb..d25d4602ab50 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1538,7 +1538,7 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
                 err = do_remount_sb(sb, flags, data, 0);
         if (!err) {
                 spin_lock(&vfsmount_lock);
-                mnt_flags |= path->mnt->mnt_flags & MNT_PNODE_MASK;
+                mnt_flags |= path->mnt->mnt_flags & MNT_PROPAGATION_MASK;
                 path->mnt->mnt_flags = mnt_flags;
                 spin_unlock(&vfsmount_lock);
         }
diff --git a/fs/pnode.h b/fs/pnode.h
index 6c7ef3252a26..1ea4ae1efcd3 100644
--- a/fs/pnode.h
+++ b/fs/pnode.h
@@ -25,7 +25,7 @@
 
 static inline void set_mnt_shared(struct vfsmount *mnt)
 {
-        mnt->mnt_flags &= ~MNT_PNODE_MASK;
+        mnt->mnt_flags &= ~MNT_SHARED_MASK;
         mnt->mnt_flags |= MNT_SHARED;
 }
 
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 5d5275364867..375d43a5d802 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -34,7 +34,16 @@ struct mnt_namespace;
 
 #define MNT_SHARED      0x1000  /* if the vfsmount is a shared mount */
 #define MNT_UNBINDABLE  0x2000  /* if the vfsmount is a unbindable mount */
-#define MNT_PNODE_MASK  0x3000  /* propagation flag mask */
+/*
+ * MNT_SHARED_MASK is the set of flags that should be cleared when a
+ * mount becomes shared.  Currently, this is only the flag that says a
+ * mount cannot be bind mounted, since this is how we create a mount
+ * that shares events with another mount.  If you add a new MNT_*
+ * flag, consider how it interacts with shared mounts.
+ */
+#define MNT_SHARED_MASK (MNT_UNBINDABLE)
+#define MNT_PROPAGATION_MASK    (MNT_SHARED | MNT_UNBINDABLE)
+
 
 struct vfsmount {
         struct list_head mnt_hash;