From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26737C54FCB for ; Thu, 23 Apr 2020 23:23:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 089772077D for ; Thu, 23 Apr 2020 23:23:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729475AbgDWXXf (ORCPT ); Thu, 23 Apr 2020 19:23:35 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:48410 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728165AbgDWXGa (ORCPT ); Thu, 23 Apr 2020 19:06:30 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jRkvK-0004b6-L3; Fri, 24 Apr 2020 00:06:26 +0100 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1jRkvJ-00E6hu-Ee; Fri, 24 Apr 2020 00:06:25 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "David Sterba" , "Greg Kroah-Hartman" , "Ben Hutchings" , "Josef Bacik" , "Qu Wenruo" Date: Fri, 24 Apr 2020 00:04:34 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 047/245] btrfs: tree-check: reduce stack consumption in check_dir_item In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.83-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: David Sterba commit e2683fc9d219430f5b78889b50cde7f40efeba7b upstream. I've noticed that the updated item checker stack consumption increased dramatically in 542f5385e20cf97447 ("btrfs: tree-checker: Add checker for dir item") tree-checker.c:check_leaf +552 (176 -> 728) The array is 255 bytes long, dynamic allocation would slow down the sanity checks so it's more reasonable to keep it on-stack. Moving the variable to the scope of use reduces the stack usage again tree-checker.c:check_leaf -264 (728 -> 464) Reviewed-by: Josef Bacik Reviewed-by: Qu Wenruo Signed-off-by: David Sterba Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- fs/btrfs/tree-checker.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/btrfs/tree-checker.c +++ b/fs/btrfs/tree-checker.c @@ -212,7 +212,6 @@ static int check_dir_item(struct btrfs_r di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item); while (cur < item_size) { - char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)]; u32 name_len; u32 data_len; u32 max_name_len; @@ -295,6 +294,8 @@ static int check_dir_item(struct btrfs_r */ if (key->type == BTRFS_DIR_ITEM_KEY || key->type == BTRFS_XATTR_ITEM_KEY) { + char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)]; + read_extent_buffer(leaf, namebuf, (unsigned long)(di + 1), name_len); name_hash = btrfs_name_hash(namebuf, name_len);