From patchwork Thu Oct 17 02:23:29 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qu Wenruo X-Patchwork-Id: 11194663 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9A0C51575 for ; Thu, 17 Oct 2019 02:23:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7918621925 for ; Thu, 17 Oct 2019 02:23:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728957AbfJQCXg (ORCPT ); Wed, 16 Oct 2019 22:23:36 -0400 Received: from mx2.suse.de ([195.135.220.15]:55420 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727328AbfJQCXg (ORCPT ); Wed, 16 Oct 2019 22:23:36 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 87BE6B235; Thu, 17 Oct 2019 02:23:33 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-devel@vger.kernel.org Subject: [PATCH v2] btrfs: qgroup: Fix wrong parameter order for trace events Date: Thu, 17 Oct 2019 10:23:29 +0800 Message-Id: <20191017022329.31545-1-wqu@suse.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org [BUG] For btrfs:qgroup_meta_reserve event, the trace event can output garbage: qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=DATA diff=2 qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=0x258792 diff=2 Since we're in qgroup_meta_reserve() trace event, the @type should never be DATA, while diff must be aligned to sectorsize (4K in this case). Only UUID and refroot is correct. [CAUSE] There are two causes for this bug: - Bad parameter order For trace event btrfs:qgroup_meta_reserve, we're passing wrong parameters. The correct parameters are: struct btrfs_root, s64 diff, int type. However the used order is: struct btrfs_root, int type, s64 diff. - @type is not even assigned What I was doing !? /facepalm [FIX] Fix the super stupid bug. Now everything works fine: qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PERTRANS diff=81920 qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384 qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=0 qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384 qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=-16384 qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384 qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=-16384 qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=16384 qgroup_meta_reserve: 0477ad60-9aeb-4040-8a03-1900844d46ba: refroot=5(FS_TREE) type=META_PREALLOC diff=-16384 Fixes: 4ee0d8832c2e ("btrfs: qgroup: Update trace events for metadata reservation") Signed-off-by: Qu Wenruo --- Changelog: v2: - Use more accurate comment about the fintuning options - Use more elegant method to output uuid --- fs/btrfs/qgroup.c | 4 ++-- include/trace/events/btrfs.h | 1 + 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c index c4bb69941c77..3ad151655eb8 100644 --- a/fs/btrfs/qgroup.c +++ b/fs/btrfs/qgroup.c @@ -3629,7 +3629,7 @@ int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes, return 0; BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize)); - trace_qgroup_meta_reserve(root, type, (s64)num_bytes); + trace_qgroup_meta_reserve(root, (s64)num_bytes, type); ret = qgroup_reserve(root, num_bytes, enforce, type); if (ret < 0) return ret; @@ -3676,7 +3676,7 @@ void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes, */ num_bytes = sub_root_meta_rsv(root, num_bytes, type); BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize)); - trace_qgroup_meta_reserve(root, type, -(s64)num_bytes); + trace_qgroup_meta_reserve(root, -(s64)num_bytes, type); btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid, num_bytes, type); } diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h index 5df604de4f11..0ebcaa153f93 100644 --- a/include/trace/events/btrfs.h +++ b/include/trace/events/btrfs.h @@ -1710,6 +1710,7 @@ TRACE_EVENT(qgroup_meta_reserve, TP_fast_assign_btrfs(root->fs_info, __entry->refroot = root->root_key.objectid; __entry->diff = diff; + __entry->type = type; ), TP_printk_btrfs("refroot=%llu(%s) type=%s diff=%lld",