From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from aserp2120.oracle.com ([141.146.126.78]:45342 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752937AbeAEUyL (ORCPT ); Fri, 5 Jan 2018 15:54:11 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.21/8.16.0.21) with SMTP id w05Kr2Ym069074 for ; Fri, 5 Jan 2018 20:54:11 GMT Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by aserp2120.oracle.com with ESMTP id 2fagch035s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Fri, 05 Jan 2018 20:54:11 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w05KsAXB018037 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Fri, 5 Jan 2018 20:54:10 GMT Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w05KsAdh000480 for ; Fri, 5 Jan 2018 20:54:10 GMT From: Liu Bo To: linux-btrfs@vger.kernel.org Subject: [PATCH v2 08/10] Btrfs: add WARN_ONCE to detect unexpected error from merge_extent_mapping Date: Fri, 5 Jan 2018 12:51:15 -0700 Message-Id: <20180105195117.5131-9-bo.li.liu@oracle.com> In-Reply-To: <20180105195117.5131-1-bo.li.liu@oracle.com> References: <20180105195117.5131-1-bo.li.liu@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: This is a subtle case, so in order to understand the problem, it'd be good to know the content of existing and em when any error occurs. Signed-off-by: Liu Bo --- v2: Remove unnecessary KERN_INFO. fs/btrfs/extent_map.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c index 6fe8b14..b5d0add 100644 --- a/fs/btrfs/extent_map.c +++ b/fs/btrfs/extent_map.c @@ -562,17 +562,23 @@ int btrfs_add_extent_mapping(struct extent_map_tree *em_tree, *em_in = existing; ret = 0; } else { + u64 orig_start = em->start; + u64 orig_len = em->len; + /* * The existing extent map is the one nearest to * the [start, start + len) range which overlaps */ ret = merge_extent_mapping(em_tree, existing, em, start); - free_extent_map(existing); if (ret) { free_extent_map(em); *em_in = NULL; + WARN_ONCE(ret, "Unexpected error %d: merge existing(start %llu len %llu) with em(start %llu len %llu)\n", + ret, existing->start, existing->len, + orig_start, orig_len); } + free_extent_map(existing); } } -- 2.9.4