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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 3D5DBC04EBF for ; Tue, 4 Dec 2018 14:23:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0DF3C206B7 for ; Tue, 4 Dec 2018 14:23:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0DF3C206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-btrfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726821AbeLDOXl (ORCPT ); Tue, 4 Dec 2018 09:23:41 -0500 Received: from mx2.suse.de ([195.135.220.15]:50114 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726400AbeLDOXj (ORCPT ); Tue, 4 Dec 2018 09:23:39 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id C710EAE18; Tue, 4 Dec 2018 14:23:36 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id F192FDAC39; Tue, 4 Dec 2018 15:23:16 +0100 (CET) Date: Tue, 4 Dec 2018 15:23:15 +0100 From: David Sterba To: Lu Fengqi Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH] btrfs: skip file_extent generation check for free_space_inode in run_delalloc_nocow Message-ID: <20181204142315.GT17773@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Lu Fengqi , linux-btrfs@vger.kernel.org References: <20181129093132.25147-1-lufq.fnst@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181129093132.25147-1-lufq.fnst@cn.fujitsu.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Nov 29, 2018 at 05:31:32PM +0800, Lu Fengqi wrote: > The btrfs/001 with inode_cache mount option will encounter the following > warning: > > WARNING: CPU: 1 PID: 23700 at fs/btrfs/inode.c:956 cow_file_range.isra.19+0x32b/0x430 [btrfs] > CPU: 1 PID: 23700 Comm: btrfs Kdump: loaded Tainted: G W O 4.20.0-rc4-custom+ #30 > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 > RIP: 0010:cow_file_range.isra.19+0x32b/0x430 [btrfs] > Call Trace: > ? free_extent_buffer+0x46/0x90 [btrfs] > run_delalloc_nocow+0x455/0x900 [btrfs] > btrfs_run_delalloc_range+0x1a7/0x360 [btrfs] > writepage_delalloc+0xf9/0x150 [btrfs] > __extent_writepage+0x125/0x3e0 [btrfs] > extent_write_cache_pages+0x1b6/0x3e0 [btrfs] > ? __wake_up_common_lock+0x63/0xc0 > extent_writepages+0x50/0x80 [btrfs] > do_writepages+0x41/0xd0 > ? __filemap_fdatawrite_range+0x9e/0xf0 > __filemap_fdatawrite_range+0xbe/0xf0 > btrfs_fdatawrite_range+0x1b/0x50 [btrfs] > __btrfs_write_out_cache+0x42c/0x480 [btrfs] > btrfs_write_out_ino_cache+0x84/0xd0 [btrfs] > btrfs_save_ino_cache+0x551/0x660 [btrfs] > commit_fs_roots+0xc5/0x190 [btrfs] > btrfs_commit_transaction+0x2bf/0x8d0 [btrfs] > btrfs_mksubvol+0x48d/0x4d0 [btrfs] > btrfs_ioctl_snap_create_transid+0x170/0x180 [btrfs] > btrfs_ioctl_snap_create_v2+0x124/0x180 [btrfs] > btrfs_ioctl+0x123f/0x3030 [btrfs] > > The file extent generation of the free space inode is equal to the last > snapshot of the file root, so the inode will be passed to cow_file_rage. > But the inode was created and its extents were preallocated in > btrfs_save_ino_cache, there are no cow copies on disk. > > The preallocated extents don't present on disk, and the > btrfs_cross_ref_exist will ignore the -ENOENT returned by > check_committed_ref, so we can directly write the inode to the disk. > > Fixes: 78d4295b1eee ("btrfs: lift some btrfs_cross_ref_exist checks in nocow path") > Signed-off-by: Lu Fengqi With updated changelog and reviewed-by added to misc-next, thanks.