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=unavailable 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 17300C2BBD4 for ; Wed, 16 Dec 2020 23:34:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C763923730 for ; Wed, 16 Dec 2020 23:34:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729988AbgLPXd4 (ORCPT ); Wed, 16 Dec 2020 18:33:56 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:25556 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730829AbgLPXdw (ORCPT ); Wed, 16 Dec 2020 18:33:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1608161546; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Iyvu3tczAymPkwWycdPC/BAXXExR62UHIGSUwLXdNqs=; b=GATxJoVUWJWG8NY/0HNJrGYtwdvgP1PJEF/mYjKxrTBr15zQ1SbeexTq50SXG2fkoTRB7x KXN79Z3HTksxGMBrJxeJQZvAWMzz//aJwYtIaH5HV8TX9pzHVyMYVqpdc0UIH0YoTUkW3g mtg/rBen9MrNU5+g8PJuydVhInNuCEo= 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-501-5DZe-w98PwK_bJ9o0z2SMw-1; Wed, 16 Dec 2020 18:32:22 -0500 X-MC-Unique: 5DZe-w98PwK_bJ9o0z2SMw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2F3C21842142; Wed, 16 Dec 2020 23:32:20 +0000 (UTC) Received: from horse.redhat.com (ovpn-112-114.rdu2.redhat.com [10.10.112.114]) by smtp.corp.redhat.com (Postfix) with ESMTP id 09B795D9D2; Wed, 16 Dec 2020 23:32:20 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 8098A225FCD; Wed, 16 Dec 2020 18:32:19 -0500 (EST) From: Vivek Goyal To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-unionfs@vger.kernel.org Cc: jlayton@kernel.org, vgoyal@redhat.com, amir73il@gmail.com, sargun@sargun.me, miklos@szeredi.hu, willy@infradead.org, jack@suse.cz, neilb@suse.com, viro@zeniv.linux.org.uk Subject: [PATCH 3/3] overlayfs: Check writeback errors w.r.t upper in ->syncfs() Date: Wed, 16 Dec 2020 18:31:49 -0500 Message-Id: <20201216233149.39025-4-vgoyal@redhat.com> In-Reply-To: <20201216233149.39025-1-vgoyal@redhat.com> References: <20201216233149.39025-1-vgoyal@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org Check for writeback error on overlay super block w.r.t "struct file" passed in ->syncfs(). As of now real error happens on upper sb. So this patch first propagates error from upper sb to overlay sb and then checks error w.r.t struct file passed in. Jeff, I know you prefer that I should rather file upper file and check error directly on on upper sb w.r.t this real upper file. While I was implementing that I thought what if file is on lower (and has not been copied up yet). In that case shall we not check writeback errors and return back to user space? That does not sound right though because, we are not checking for writeback errors on this file. Rather we are checking for any error on superblock. Upper might have an error and we should report it to user even if file in question is a lower file. And that's why I fell back to this approach. But I am open to change it if there are issues in this method. Signed-off-by: Vivek Goyal --- fs/overlayfs/ovl_entry.h | 2 ++ fs/overlayfs/super.c | 15 ++++++++++++--- 2 files changed, 14 insertions(+), 3 deletions(-) diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h index 1b5a2094df8e..a08fd719ee7b 100644 --- a/fs/overlayfs/ovl_entry.h +++ b/fs/overlayfs/ovl_entry.h @@ -79,6 +79,8 @@ struct ovl_fs { atomic_long_t last_ino; /* Whiteout dentry cache */ struct dentry *whiteout; + /* Protects multiple sb->s_wb_err update from upper_sb . */ + spinlock_t errseq_lock; }; static inline struct vfsmount *ovl_upper_mnt(struct ovl_fs *ofs) diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index b4d92e6fa5ce..e7bc4492205e 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -291,7 +291,7 @@ int ovl_syncfs(struct file *file) struct super_block *sb = file->f_path.dentry->d_sb; struct ovl_fs *ofs = sb->s_fs_info; struct super_block *upper_sb; - int ret; + int ret, ret2; ret = 0; down_read(&sb->s_umount); @@ -310,10 +310,18 @@ int ovl_syncfs(struct file *file) ret = sync_filesystem(upper_sb); up_read(&upper_sb->s_umount); + /* Update overlay sb->s_wb_err */ + if (errseq_check(&upper_sb->s_wb_err, sb->s_wb_err)) { + /* Upper sb has errors since last time */ + spin_lock(&ofs->errseq_lock); + errseq_check_and_advance(&upper_sb->s_wb_err, &sb->s_wb_err); + spin_unlock(&ofs->errseq_lock); + } + ret2 = errseq_check_and_advance(&sb->s_wb_err, &file->f_sb_err); out: up_read(&sb->s_umount); - return ret; + return ret ? ret : ret2; } /** @@ -1903,6 +1911,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) if (!cred) goto out_err; + spin_lock_init(&ofs->errseq_lock); /* Is there a reason anyone would want not to share whiteouts? */ ofs->share_whiteout = true; @@ -1975,7 +1984,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) sb->s_stack_depth = ovl_upper_mnt(ofs)->mnt_sb->s_stack_depth; sb->s_time_gran = ovl_upper_mnt(ofs)->mnt_sb->s_time_gran; - + sb->s_wb_err = errseq_sample(&ovl_upper_mnt(ofs)->mnt_sb->s_wb_err); } oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); err = PTR_ERR(oe); -- 2.25.4