Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid

[sfrench/cifs-2.6.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index fbba8b17330d40d4daff7cf61763853cfd414395..5b66b2b3624d0da0efe405a6ecb4c86e07a0b58f 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1686,6 +1686,33 @@ void drop_collected_mounts(struct vfsmount *mnt)
        namespace_unlock();
 }
 
+/**
+ * clone_private_mount - create a private clone of a path
+ *
+ * This creates a new vfsmount, which will be the clone of @path.  The new will
+ * not be attached anywhere in the namespace and will be private (i.e. changes
+ * to the originating mount won't be propagated into this).
+ *
+ * Release with mntput().
+ */
+struct vfsmount *clone_private_mount(struct path *path)
+{
+       struct mount *old_mnt = real_mount(path->mnt);
+       struct mount *new_mnt;
+
+       if (IS_MNT_UNBINDABLE(old_mnt))
+               return ERR_PTR(-EINVAL);
+
+       down_read(&namespace_sem);
+       new_mnt = clone_mnt(old_mnt, path->dentry, CL_PRIVATE);
+       up_read(&namespace_sem);
+       if (IS_ERR(new_mnt))
+               return ERR_CAST(new_mnt);
+
+       return &new_mnt->mnt;
+}
+EXPORT_SYMBOL_GPL(clone_private_mount);
+
 int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,
                   struct vfsmount *root)
 {