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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 234ACC433E0 for ; Mon, 22 Feb 2021 14:13:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D889D64E20 for ; Mon, 22 Feb 2021 14:13:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231907AbhBVONr (ORCPT ); Mon, 22 Feb 2021 09:13:47 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:37144 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232354AbhBVOM6 (ORCPT ); Mon, 22 Feb 2021 09:12:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614003091; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=l6KPUd85tU8TFpS6PeiKizzY1NP5pW5a6up88tmrJEY=; b=c40SEIx1PJ01C7tGA0JcquTm8p6Q9ODfhopiAP6EjOw0CvbgkOi49PoLCuwz+NFITDP6sq 45j8xMnAPs0V0NfE9oz0ZaTAWWEn3XygVV+Yh8wZiE4iuxphJMf8IobQCnoZIIU/fTe3aT 9ZXD/7+5mHALbB/jEhiDuX+GWPLY84U= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-215-x6EEBR5tOSWNZlubVDYkFw-1; Mon, 22 Feb 2021 09:11:28 -0500 X-MC-Unique: x6EEBR5tOSWNZlubVDYkFw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A1033803F62; Mon, 22 Feb 2021 14:11:27 +0000 (UTC) Received: from bfoster (ovpn-119-92.rdu2.redhat.com [10.10.119.92]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2007C2BFE3; Mon, 22 Feb 2021 14:11:27 +0000 (UTC) Date: Mon, 22 Feb 2021 09:11:25 -0500 From: Brian Foster To: "Darrick J. Wong" Cc: sandeen@sandeen.net, linux-xfs@vger.kernel.org Subject: Re: [PATCH 1/4] xfs_repair: set NEEDSREPAIR the first time we write to a filesystem Message-ID: <20210222141125.GA886774@bfoster> References: <161370467351.2389661.12577563230109429304.stgit@magnolia> <161370467918.2389661.3070940511114217130.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <161370467918.2389661.3070940511114217130.stgit@magnolia> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Thu, Feb 18, 2021 at 07:17:59PM -0800, Darrick J. Wong wrote: > 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 > --- Modulo Eric's feedback: 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 > */ >