fs/cifs: make share unaccessible at root level mountable

[firefly-linux-kernel-4.4.55.git] / fs / cifs / cifsfs.c

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index cbc0f4bca0c0dfa73b6a545fb6978a72b1a702ef..450578097fb7f093142ed4b1c10130a774a17c3f 100644 (file)
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -686,6 +686,14 @@ cifs_do_mount(struct file_system_type *fs_type,
                goto out_cifs_sb;
        }
 
+       if (volume_info->prepath) {
+               cifs_sb->prepath = kstrdup(volume_info->prepath, GFP_KERNEL);
+               if (cifs_sb->prepath == NULL) {
+                       root = ERR_PTR(-ENOMEM);
+                       goto out_cifs_sb;
+               }
+       }
+
        cifs_setup_cifs_sb(volume_info, cifs_sb);
 
        rc = cifs_mount(cifs_sb, volume_info);
@@ -724,7 +732,11 @@ cifs_do_mount(struct file_system_type *fs_type,
                sb->s_flags |= MS_ACTIVE;
        }
 
-       root = cifs_get_root(volume_info, sb);
+       if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH)
+               root = dget(sb->s_root);
+       else
+               root = cifs_get_root(volume_info, sb);
+
        if (IS_ERR(root))
                goto out_super;