From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 83ECC6B0069 for ; Mon, 3 Oct 2016 12:37:56 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id d64so87157123wmh.1 for ; Mon, 03 Oct 2016 09:37:56 -0700 (PDT) Received: from newverein.lst.de (verein.lst.de. [213.95.11.211]) by mx.google.com with ESMTPS id a2si3127873wme.84.2016.10.03.09.37.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 03 Oct 2016 09:37:55 -0700 (PDT) Date: Mon, 3 Oct 2016 18:37:54 +0200 From: Christoph Hellwig Subject: Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Message-ID: <20161003163754.GB1496@lst.de> References: <1475189370-31634-1-git-send-email-ross.zwisler@linux.intel.com> <1475189370-31634-11-git-send-email-ross.zwisler@linux.intel.com> <20161003105949.GP6457@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161003105949.GP6457@quack2.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: Ross Zwisler , linux-kernel@vger.kernel.org, Theodore Ts'o , Alexander Viro , Andreas Dilger , Andrew Morton , Christoph Hellwig , Dan Williams , Dave Chinner , Jan Kara , Matthew Wilcox , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, linux-xfs@vger.kernel.org On Mon, Oct 03, 2016 at 12:59:49PM +0200, Jan Kara wrote: > I'm not quite sure if it is OK to call ->iomap_begin() without ever calling > ->iomap_end. Specifically the comment before iomap_apply() says: > > "It is assumed that the filesystems will lock whatever resources they > require in the iomap_begin call, and release them in the iomap_end call." > > so what you do could result in unbalanced allocations / locks / whatever. > Christoph? Indeed. For XFS we only rely on iomap_end for error handling at the moment, but it is intended to be paired for locking, as cluster file systems like gfs2 requested this. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org