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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 9AADCC3A5A0 for ; Mon, 20 Apr 2020 12:44:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7677B206E9 for ; Mon, 20 Apr 2020 12:44:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587386686; bh=bAe1FRdeDniFj9uG2cgsWCRDVxEI8geVgSonvd04wvw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2gDKyRs23wFfVTRAiR43wmit+Q4N4AaNC3HB7w8ymnA94cGKN3oxl15J+0KKG8JOE 39sGvw0vW+vKG5mVLuuAq2JCX3lKo8GvqWvs82iQkL+isLT33HGnAvARQxH3fs5/JL 9G5hcjsVIJ8nBaN4hOUL/eBFH3OwT1bM2qk5O9JA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728616AbgDTMol (ORCPT ); Mon, 20 Apr 2020 08:44:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:38570 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728595AbgDTMof (ORCPT ); Mon, 20 Apr 2020 08:44:35 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 402D22075A; Mon, 20 Apr 2020 12:44:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587386674; bh=bAe1FRdeDniFj9uG2cgsWCRDVxEI8geVgSonvd04wvw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=03uJ5m9qZ36z2IGfb8H/oDlh5mK2qtD6bYUEWZwQtmRaEv+Gp0jj1BwOhbqOkJK21 XeHxLUP1wuLLiUJaUxscnsVGSof/TqxVGRUjZ4jzCyArRCZrw84aW3oaQn8TI1JlfI IlhzGz2HyCgcoFFCCdSUV71b4ndePseHfq45ozjU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Filipe Manana , Josef Bacik , David Sterba Subject: [PATCH 5.6 51/71] btrfs: check commit root generation in should_ignore_root Date: Mon, 20 Apr 2020 14:39:05 +0200 Message-Id: <20200420121519.463459744@linuxfoundation.org> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200420121508.491252919@linuxfoundation.org> References: <20200420121508.491252919@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josef Bacik commit 4d4225fc228e46948486d8b8207955f0c031b92e upstream. Previously we would set the reloc root's last snapshot to transid - 1. However there was a problem with doing this, and we changed it to setting the last snapshot to the generation of the commit node of the fs root. This however broke should_ignore_root(). The assumption is that if we are in a generation newer than when the reloc root was created, then we would find the reloc root through normal backref lookups, and thus can ignore any fs roots we find with an old enough reloc root. Now that the last snapshot could be considerably further in the past than before, we'd end up incorrectly ignoring an fs root. Thus we'd find no nodes for the bytenr we were searching for, and we'd fail to relocate anything. We'd loop through the relocate code again and see that there were still used space in that block group, attempt to relocate those bytenr's again, fail in the same way, and just loop like this forever. This is tricky in that we have to not modify the fs root at all during this time, so we need to have a block group that has data in this fs root that is not shared by any other root, which is why this has been difficult to reproduce. Fixes: 054570a1dc94 ("Btrfs: fix relocation incorrectly dropping data references") CC: stable@vger.kernel.org # 4.9+ Reviewed-by: Filipe Manana Signed-off-by: Josef Bacik Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/relocation.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -561,8 +561,8 @@ static int should_ignore_root(struct btr if (!reloc_root) return 0; - if (btrfs_root_last_snapshot(&reloc_root->root_item) == - root->fs_info->running_transaction->transid - 1) + if (btrfs_header_generation(reloc_root->commit_root) == + root->fs_info->running_transaction->transid) return 0; /* * if there is reloc tree and it was created in previous