From patchwork Mon Feb 23 19:48:52 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Filipe Manana X-Patchwork-Id: 5867961 Return-Path: X-Original-To: patchwork-linux-btrfs@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id A0D2A9F36A for ; Mon, 23 Feb 2015 19:59:58 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E050B2060E for ; Mon, 23 Feb 2015 19:59:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C94B8205E3 for ; Mon, 23 Feb 2015 19:59:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752308AbbBWT7r (ORCPT ); Mon, 23 Feb 2015 14:59:47 -0500 Received: from victor.provo.novell.com ([137.65.250.26]:57909 "EHLO prv3-mh.provo.novell.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751861AbbBWT7r (ORCPT ); Mon, 23 Feb 2015 14:59:47 -0500 Received: from debian3.lan (prv-ext-foundry1int.gns.novell.com [137.65.251.240]) by prv3-mh.provo.novell.com with ESMTP (NOT encrypted); Mon, 23 Feb 2015 12:59:34 -0700 From: Filipe Manana To: linux-btrfs@vger.kernel.org Cc: Filipe Manana Subject: [PATCH] Btrfs: fix off-by-one logic error in btrfs_realloc_node Date: Mon, 23 Feb 2015 19:48:52 +0000 Message-Id: <1424720932-15388-1-git-send-email-fdmanana@suse.com> X-Mailer: git-send-email 2.1.3 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The end_slot variable actually matches the number of pointers in the node and not the last slot (which is 'nritems - 1'). Therefore in order to check that the current slot in the for loop doesn't match the last one, the correct logic is to check if 'i' is less than 'end_slot - 1' and not 'end_slot - 2'. Fix this and set end_slot to be 'nritems - 1', as it's less confusing since the variable name implies it's inclusive rather then exclusive. Signed-off-by: Filipe Manana --- fs/btrfs/ctree.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 9936421..6d67f32 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1645,14 +1645,14 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, parent_nritems = btrfs_header_nritems(parent); blocksize = root->nodesize; - end_slot = parent_nritems; + end_slot = parent_nritems - 1; - if (parent_nritems == 1) + if (parent_nritems <= 1) return 0; btrfs_set_lock_blocking(parent); - for (i = start_slot; i < end_slot; i++) { + for (i = start_slot; i <= end_slot; i++) { int close = 1; btrfs_node_key(parent, &disk_key, i); @@ -1669,7 +1669,7 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans, other = btrfs_node_blockptr(parent, i - 1); close = close_blocks(blocknr, other, blocksize); } - if (!close && i < end_slot - 2) { + if (!close && i < end_slot) { other = btrfs_node_blockptr(parent, i + 1); close = close_blocks(blocknr, other, blocksize); }