From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH] jbd2: Fix dbench4 performance regression for 'nobarrier' mounts Date: Fri, 28 Apr 2017 08:03:24 -0700 Message-ID: <20170428150324.GA20122@infradead.org> References: <20170428095934.11583-1-jack@suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ted Tso , linux-ext4@vger.kernel.org, Christoph Hellwig , stable@vger.kernel.org To: Jan Kara Return-path: Content-Disposition: inline In-Reply-To: <20170428095934.11583-1-jack@suse.cz> Sender: stable-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Fri, Apr 28, 2017 at 11:59:34AM +0200, Jan Kara wrote: > Fix the problem by making sure journal superblock writes are always > treated as synchronous since they generally block progress of the > journalling machinery and thus the whole filesystem. The callchains leading down to jbd2_write_superblock looks a little suspicious to me. It seems like jbd2_journal_commit_transaction will actually call without FUA in the JBD2_FLUSHED case. Is that really intentional, and if yes should it be documented? Except for that it would seem more useful to move to a "bool preflush" argument passed down. But I guess we'll need a quick fix first, for that: Reviewed-by: Christoph Hellwig