From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH v4 10/12] dax: add struct iomap based DAX PMD support Date: Mon, 3 Oct 2016 18:37:54 +0200 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 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 To: Jan Kara Return-path: Content-Disposition: inline In-Reply-To: <20161003105949.GP6457@quack2.suse.cz> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:54924 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751260AbcJCQh5 (ORCPT ); Mon, 3 Oct 2016 12:37:57 -0400 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: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs 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. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753124AbcJCQiE (ORCPT ); Mon, 3 Oct 2016 12:38:04 -0400 Received: from verein.lst.de ([213.95.11.211]:54924 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751260AbcJCQh5 (ORCPT ); Mon, 3 Oct 2016 12:37:57 -0400 Date: Mon, 3 Oct 2016 18:37:54 +0200 From: Christoph Hellwig 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@ml01.01.org, linux-xfs@vger.kernel.org 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> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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.