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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 20675ECAAA1 for ; Mon, 24 Oct 2022 13:08:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235535AbiJXNIv (ORCPT ); Mon, 24 Oct 2022 09:08:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235222AbiJXNIX (ORCPT ); Mon, 24 Oct 2022 09:08:23 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0985A8305B; Mon, 24 Oct 2022 05:21:42 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 6C6D3B81620; Mon, 24 Oct 2022 12:15:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A9733C433C1; Mon, 24 Oct 2022 12:15:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666613750; bh=rCB0Xv+xi/SjS1Z1j3Vilkp/16M2refyx39jmGCCBTE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t9FYvUg1jBd1PDnt6FpIK5BousDMKVrVnHpFq/9GeY+OCCN7I6AX56OltRGSki+J1 hjS82INMvsb17EcpEI585ItbQQnc/tFUlKShPb0dAKxaNt2AqWZUaZms6IVF/tjdYp kfoBxOuDAW50oUwHwcIqWcOeEca87ibq5HRFxX+Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Qu Wenruo , David Sterba , Sasha Levin Subject: [PATCH 5.4 226/255] btrfs: scrub: try to fix super block errors Date: Mon, 24 Oct 2022 13:32:16 +0200 Message-Id: <20221024113010.623921155@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113002.471093005@linuxfoundation.org> References: <20221024113002.471093005@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Qu Wenruo [ Upstream commit f9eab5f0bba76742af654f33d517bf62a0db8f12 ] [BUG] The following script shows that, although scrub can detect super block errors, it never tries to fix it: mkfs.btrfs -f -d raid1 -m raid1 $dev1 $dev2 xfs_io -c "pwrite 67108864 4k" $dev2 mount $dev1 $mnt btrfs scrub start -B $dev2 btrfs scrub start -Br $dev2 umount $mnt The first scrub reports the super error correctly: scrub done for f3289218-abd3-41ac-a630-202f766c0859 Scrub started: Tue Aug 2 14:44:11 2022 Status: finished Duration: 0:00:00 Total to scrub: 1.26GiB Rate: 0.00B/s Error summary: super=1 Corrected: 0 Uncorrectable: 0 Unverified: 0 But the second read-only scrub still reports the same super error: Scrub started: Tue Aug 2 14:44:11 2022 Status: finished Duration: 0:00:00 Total to scrub: 1.26GiB Rate: 0.00B/s Error summary: super=1 Corrected: 0 Uncorrectable: 0 Unverified: 0 [CAUSE] The comments already shows that super block can be easily fixed by committing a transaction: /* * If we find an error in a super block, we just report it. * They will get written with the next transaction commit * anyway */ But the truth is, such assumption is not always true, and since scrub should try to repair every error it found (except for read-only scrub), we should really actively commit a transaction to fix this. [FIX] Just commit a transaction if we found any super block errors, after everything else is done. We cannot do this just after scrub_supers(), as btrfs_commit_transaction() will try to pause and wait for the running scrub, thus we can not call it with scrub_lock hold. Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/scrub.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index e5db948daa12..45809f75692e 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -3849,6 +3849,7 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, int ret; struct btrfs_device *dev; unsigned int nofs_flag; + bool need_commit = false; if (btrfs_fs_closing(fs_info)) return -EAGAIN; @@ -3961,6 +3962,12 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, */ nofs_flag = memalloc_nofs_save(); if (!is_dev_replace) { + u64 old_super_errors; + + spin_lock(&sctx->stat_lock); + old_super_errors = sctx->stat.super_errors; + spin_unlock(&sctx->stat_lock); + btrfs_info(fs_info, "scrub: started on devid %llu", devid); /* * by holding device list mutex, we can @@ -3969,6 +3976,16 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, mutex_lock(&fs_info->fs_devices->device_list_mutex); ret = scrub_supers(sctx, dev); mutex_unlock(&fs_info->fs_devices->device_list_mutex); + + spin_lock(&sctx->stat_lock); + /* + * Super block errors found, but we can not commit transaction + * at current context, since btrfs_commit_transaction() needs + * to pause the current running scrub (hold by ourselves). + */ + if (sctx->stat.super_errors > old_super_errors && !sctx->readonly) + need_commit = true; + spin_unlock(&sctx->stat_lock); } if (!ret) @@ -3995,6 +4012,25 @@ int btrfs_scrub_dev(struct btrfs_fs_info *fs_info, u64 devid, u64 start, scrub_workers_put(fs_info); scrub_put_ctx(sctx); + /* + * We found some super block errors before, now try to force a + * transaction commit, as scrub has finished. + */ + if (need_commit) { + struct btrfs_trans_handle *trans; + + trans = btrfs_start_transaction(fs_info->tree_root, 0); + if (IS_ERR(trans)) { + ret = PTR_ERR(trans); + btrfs_err(fs_info, + "scrub: failed to start transaction to fix super block errors: %d", ret); + return ret; + } + ret = btrfs_commit_transaction(trans); + if (ret < 0) + btrfs_err(fs_info, + "scrub: failed to commit transaction to fix super block errors: %d", ret); + } return ret; out: scrub_workers_put(fs_info); -- 2.35.1