From patchwork Fri Feb 19 03:17:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 12094697 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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 E997EC433E0 for ; Fri, 19 Feb 2021 03:18:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C34AD64ED7 for ; Fri, 19 Feb 2021 03:18:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229553AbhBSDSl (ORCPT ); Thu, 18 Feb 2021 22:18:41 -0500 Received: from mail.kernel.org ([198.145.29.99]:53272 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229480AbhBSDSk (ORCPT ); Thu, 18 Feb 2021 22:18:40 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 70FBB64EBD; Fri, 19 Feb 2021 03:17:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1613704679; bh=s4FoZOx3TiRxJ9ZdtAVgORv/e23fpP/nOZ9lw9lz5Tc=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=KatYIrzV3DstKp1aYi6HGvOkuFcCMAZkPAKuLbGdEHU5SPw+avkarr8SSysSEoFbd NoE01M9zy8GMS6IQ+X2B6ws0hKUBNxwF80FBdcpr4nD10yUrGXw7DW2nyx/Mw6B2/h Pw3mNsUM1Tb4p4MPxAQ6kfJrGa1a7VFceFJVajQ4pFvwbQ/GCMu0yTsIREfhoZuayF 7vyzt083mr2CRRc/VJmCqriVKE3gIr3jeJSgzW4pixAmAU/n+bFRN9zZvQFCDdoRUM MD02P3iq2UDhdkes/lkC5vF+yabvjAsRLYZOF8SLRUukDiKvqYJKxW8SWkgF9mM1lX fhXjh11nqyx3w== Subject: [PATCH 1/4] xfs_repair: set NEEDSREPAIR the first time we write to a filesystem From: "Darrick J. Wong" To: sandeen@sandeen.net, djwong@kernel.org Cc: linux-xfs@vger.kernel.org, bfoster@redhat.com Date: Thu, 18 Feb 2021 19:17:59 -0800 Message-ID: <161370467918.2389661.3070940511114217130.stgit@magnolia> In-Reply-To: <161370467351.2389661.12577563230109429304.stgit@magnolia> References: <161370467351.2389661.12577563230109429304.stgit@magnolia> User-Agent: StGit/0.19 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Darrick J. Wong Add a hook to the buffer cache so that xfs_repair can intercept the first write to a V5 filesystem to set the NEEDSREPAIR flag. In the event that xfs_repair dirties the filesystem and goes down, this ensures that the sysadmin will have to re-start repair before mounting. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster --- include/xfs_mount.h | 4 ++ libxfs/rdwr.c | 4 ++ repair/xfs_repair.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 109 insertions(+), 1 deletion(-) diff --git a/include/xfs_mount.h b/include/xfs_mount.h index 75230ca5..f93a9f11 100644 --- a/include/xfs_mount.h +++ b/include/xfs_mount.h @@ -11,6 +11,8 @@ struct xfs_inode; struct xfs_buftarg; struct xfs_da_geometry; +typedef void (*buf_writeback_fn)(struct xfs_buf *bp); + /* * Define a user-level mount structure with all we need * in order to make use of the numerous XFS_* macros. @@ -95,6 +97,8 @@ typedef struct xfs_mount { int qi_dqperchunk; } *m_quotainfo; + buf_writeback_fn m_buf_writeback_fn; + /* * xlog is defined in libxlog and thus is not intialized by libxfs. This * allows an application to initialize and store a reference to the log diff --git a/libxfs/rdwr.c b/libxfs/rdwr.c index ac783ce3..ca272387 100644 --- a/libxfs/rdwr.c +++ b/libxfs/rdwr.c @@ -812,6 +812,10 @@ libxfs_bwrite( return bp->b_error; } + /* Trigger the writeback hook if there is one. */ + if (bp->b_mount->m_buf_writeback_fn) + bp->b_mount->m_buf_writeback_fn(bp); + /* * clear any pre-existing error status on the buffer. This can occur if * the buffer is corrupt on disk and the repair process doesn't clear diff --git a/repair/xfs_repair.c b/repair/xfs_repair.c index 90d1a95a..8eb7da53 100644 --- a/repair/xfs_repair.c +++ b/repair/xfs_repair.c @@ -725,7 +725,7 @@ clear_needsrepair( * that everything is ok with the ondisk filesystem. Make sure any * dirty buffers are sent to disk and that the disks have persisted * writes to stable storage. If that fails, leave NEEDSREPAIR in - * place. Don't purge the buffer cache here since we're not done yet. + * place. */ error = -libxfs_flush_mount(mp); if (error) { @@ -751,6 +751,102 @@ clear_needsrepair( libxfs_buf_relse(bp); } +static void +update_sb_crc_only( + struct xfs_buf *bp) +{ + xfs_buf_update_cksum(bp, XFS_SB_CRC_OFF); +} + +/* Forcibly write the primary superblock with the NEEDSREPAIR flag set. */ +static void +force_needsrepair( + struct xfs_mount *mp) +{ + struct xfs_buf_ops fake_ops; + struct xfs_buf *bp; + int error; + + if (!xfs_sb_version_hascrc(&mp->m_sb) || + xfs_sb_version_needsrepair(&mp->m_sb)) + return; + + bp = libxfs_getsb(mp); + if (!bp || bp->b_error) { + do_log( + _("couldn't get superblock to set needsrepair, err=%d\n"), + bp ? bp->b_error : ENOMEM); + } else { + /* + * It's possible that we need to set NEEDSREPAIR before we've + * had a chance to fix the summary counters in the primary sb. + * With the exception of those counters, phase 1 already + * ensured that the geometry makes sense. + * + * Bad summary counters in the primary super can cause the + * write verifier to fail, so substitute a dummy that only sets + * the CRC. In the event of a crash, NEEDSREPAIR will prevent + * the kernel from mounting our potentially damaged filesystem + * until repair is run again, so it's ok to bypass the usual + * verification in this one case. + */ + fake_ops = xfs_sb_buf_ops; /* struct copy */ + fake_ops.verify_write = update_sb_crc_only; + + mp->m_sb.sb_features_incompat |= + XFS_SB_FEAT_INCOMPAT_NEEDSREPAIR; + libxfs_sb_to_disk(bp->b_addr, &mp->m_sb); + + /* Force the primary super to disk immediately. */ + bp->b_ops = &fake_ops; + error = -libxfs_bwrite(bp); + bp->b_ops = &xfs_sb_buf_ops; + if (error) + do_log(_("couldn't force needsrepair, err=%d\n"), error); + } + if (bp) + libxfs_buf_relse(bp); +} + +/* + * Intercept the first non-super write to the filesystem so we can set + * NEEDSREPAIR to protect the filesystem from mount in case of a crash. + */ +static void +repair_capture_writeback( + struct xfs_buf *bp) +{ + struct xfs_mount *mp = bp->b_mount; + static pthread_mutex_t wb_mutex = PTHREAD_MUTEX_INITIALIZER; + + /* + * This write hook ignores any buffer that looks like a superblock to + * avoid hook recursion when setting NEEDSREPAIR. Higher level code + * modifying an sb must control the flag manually. + */ + if (bp->b_ops == &xfs_sb_buf_ops || bp->b_bn == XFS_SB_DADDR) + return; + + pthread_mutex_lock(&wb_mutex); + + /* + * If someone else already dropped the hook, then needsrepair has + * already been set on the filesystem and we can unlock. + */ + if (mp->m_buf_writeback_fn != repair_capture_writeback) + goto unlock; + + /* + * If we get here, the buffer being written is not a superblock, and + * needsrepair needs to be set. The hook is kept in place to plug all + * other writes until the sb write finishes. + */ + force_needsrepair(mp); + mp->m_buf_writeback_fn = NULL; +unlock: + pthread_mutex_unlock(&wb_mutex); +} + int main(int argc, char **argv) { @@ -847,6 +943,10 @@ main(int argc, char **argv) if (verbose > 2) mp->m_flags |= LIBXFS_MOUNT_WANT_CORRUPTED; + /* Capture the first writeback so that we can set needsrepair. */ + if (xfs_sb_version_hascrc(&mp->m_sb)) + mp->m_buf_writeback_fn = repair_capture_writeback; + /* * set XFS-independent status vars from the mount/sb structure */