ovl: adhere to the vfs_ vs. ovl_do_ conventions for xattrs

Call ovl_do_*xattr() when accessing an overlay private xattr, vfs_*xattr()
otherwise.

This has an effect on debug output, which is made more consistent by this
patch.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/copy_up.c

@@ -840,14 +840,14 @@ static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
 	 * don't want that to happen for normal copy-up operation.
 	 */
 	if (capability) {
-		err = ovl_do_setxattr(upperpath.dentry, XATTR_NAME_CAPS,
+		err = vfs_setxattr(upperpath.dentry, XATTR_NAME_CAPS,
 				   capability, cap_size, 0);
 		if (err)
 			goto out_free;
 	}
 
 
-	err = vfs_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);
+	err = ovl_do_removexattr(upperpath.dentry, OVL_XATTR_METACOPY);
 	if (err)
 		goto out_free;
 

fs/overlayfs/super.c

@@ -1327,7 +1327,7 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
 		pr_warn("upper fs does not support xattr, falling back to index=off and metacopy=off.\n");
 		err = 0;
 	} else {
-		vfs_removexattr(ofs->workdir, OVL_XATTR_OPAQUE);
+		ovl_do_removexattr(ofs->workdir, OVL_XATTR_OPAQUE);
 	}
 
 	/*