From: Dave Chinner Subject: Re: [RFC]jbd2: use GFP_NOFS for blkdev_issue_flush Date: Mon, 16 Apr 2012 08:44:27 +1000 Message-ID: <20120415224427.GV6734@dastard> References: <4F878F17.2030900@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, tytso@mit.edu To: Shaohua Li Return-path: Received: from ipmail06.adl6.internode.on.net ([150.101.137.145]:21161 "EHLO ipmail06.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752074Ab2DOWoa (ORCPT ); Sun, 15 Apr 2012 18:44:30 -0400 Content-Disposition: inline In-Reply-To: <4F878F17.2030900@kernel.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Apr 13, 2012 at 10:27:35AM +0800, Shaohua Li wrote: > > flush request is issued in transaction commit code path, so looks using > GFP_KERNEL to allocate memory for flush request bio falls into the classic > deadlock issue. I saw btrfs and dm get it right, but ext4, xfs and md are > using GFP_KERNEL, which makes me confused. Hoping filesystem developers > clarify. Only one of the 5 calls XFS makes to blkdev_issue_flush() is questionable. Probably should use GFP_NOFS by default, though, so we don't trip over this problem... Cheers, Dave. -- Dave Chinner david@fromorbit.com