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=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 1B9AFC48BD6 for ; Thu, 27 Jun 2019 06:15:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8306204FD for ; Thu, 27 Jun 2019 06:15:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726425AbfF0GPa (ORCPT ); Thu, 27 Jun 2019 02:15:30 -0400 Received: from mx2.suse.de ([195.135.220.15]:53582 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725770AbfF0GPa (ORCPT ); Thu, 27 Jun 2019 02:15:30 -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 816E2AEB8; Thu, 27 Jun 2019 06:15:29 +0000 (UTC) From: Qu Wenruo To: linux-btrfs@vger.kernel.org Cc: James Harvey Subject: [PATCH RESEND] btrfs: inode: Don't compress if NODATASUM or NODATACOW set Date: Thu, 27 Jun 2019 14:15:17 +0800 Message-Id: <20190627061517.2112-1-wqu@suse.com> X-Mailer: git-send-email 2.22.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org As btrfs(5) specified: Note If nodatacow or nodatasum are enabled, compression is disabled. If NODATASUM or NODATACOW set, we should not compress the extent. Normally NODATACOW is detected properly in run_delalloc_range() so compression won't happen for NODATACOW. However for NODATASUM we don't have any check, and it can cause compressed extent without csum pretty easily, just by: mkfs.btrfs -f $dev mount $dev $mnt -o nodatasum touch $mnt/foobar mount -o remount,datasum,compress $mnt xfs_io -f -c "pwrite 0 128K" $mnt/foobar And in fact, we have bug report about corrupted compressed extent without proper data checksum so even RAID1 can't recover the corruption. (https://bugzilla.kernel.org/show_bug.cgi?id=199707) Running compression without proper checksum could cause more damage when corruption happens, so there is no need to allow compression for NODATACSUM. Reported-by: James Harvey Signed-off-by: Qu Wenruo --- fs/btrfs/inode.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index a2aabdb85226..4e0c7f18fa3a 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -398,6 +398,14 @@ static inline int inode_need_compress(struct inode *inode, u64 start, u64 end) { struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + /* + * Btrfs doesn't support compression without csum or CoW. + * This should have the highest priority. + */ + if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW || + BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) + return 0; + /* force compress */ if (btrfs_test_opt(fs_info, FORCE_COMPRESS)) return 1; -- 2.22.0