From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752225AbcEIOzg (ORCPT ); Mon, 9 May 2016 10:55:36 -0400 Received: from mga11.intel.com ([192.55.52.93]:6789 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751152AbcEIOza (ORCPT ); Mon, 9 May 2016 10:55:30 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,601,1455004800"; d="scan'208";a="975792278" Date: Mon, 9 May 2016 08:55:27 -0600 From: Ross Zwisler To: "Verma, Vishal L" Cc: "hch@infradead.org" , "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" , "xfs@oss.sgi.com" , "linux-nvdimm@ml01.01.org" , "jmoyer@redhat.com" , "linux-mm@kvack.org" , "Williams, Dan J" , "axboe@fb.com" , "akpm@linux-foundation.org" , "linux-fsdevel@vger.kernel.org" , "ross.zwisler@linux.intel.com" , "linux-ext4@vger.kernel.org" , "boaz@plexistor.com" , "Wilcox, Matthew R" , "david@fromorbit.com" , "jack@suse.cz" Subject: Re: [PATCH v5 3/5] dax: use sb_issue_zerout instead of calling dax_clear_sectors Message-ID: <20160509145527.GA31079@linux.intel.com> Mail-Followup-To: Ross Zwisler , "Verma, Vishal L" , "hch@infradead.org" , "linux-kernel@vger.kernel.org" , "linux-block@vger.kernel.org" , "xfs@oss.sgi.com" , "linux-nvdimm@ml01.01.org" , "jmoyer@redhat.com" , "linux-mm@kvack.org" , "Williams, Dan J" , "axboe@fb.com" , "akpm@linux-foundation.org" , "linux-fsdevel@vger.kernel.org" , "linux-ext4@vger.kernel.org" , "boaz@plexistor.com" , "Wilcox, Matthew R" , "david@fromorbit.com" , "jack@suse.cz" References: <1462571591-3361-1-git-send-email-vishal.l.verma@intel.com> <1462571591-3361-4-git-send-email-vishal.l.verma@intel.com> <20160508085203.GA10160@infradead.org> <1462733173.3006.7.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1462733173.3006.7.camel@intel.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, May 08, 2016 at 06:46:13PM +0000, Verma, Vishal L wrote: > On Sun, 2016-05-08 at 01:52 -0700, Christoph Hellwig wrote: > > On Fri, May 06, 2016 at 03:53:09PM -0600, Vishal Verma wrote: > > > > > > From: Matthew Wilcox > > > > > > dax_clear_sectors() cannot handle poisoned blocks.  These must be > > > zeroed using the BIO interface instead.  Convert ext2 and XFS to > > > use > > > only sb_issue_zerout(). > > > > > > Signed-off-by: Matthew Wilcox > > > [vishal: Also remove the dax_clear_sectors function entirely] > > > Signed-off-by: Vishal Verma > > Just to make sure:  the existing sb_issue_zerout as in 4.6-rc > > is already doing the right thing for DAX?  I've got a pending > > patchset > > for XFS that introduces another dax_clear_sectors users, but if it's > > already safe to use blkdev_issue_zeroout I can switch to that and > > avoid > > the merge conflict. > > I believe so - Jan has moved all unwritten extent conversions out of > DAX with his patch set, and I believe zeroing through the driver is > always fine. Ross or Jan could confirm though.  Yep, I believe that the existing sb_issue_zeroout() as of v4.6-rc* does the right thing. We'll end up calling sb_issue_zeroout() => blkdev_issue_zeroout() => __blkdev_issue_zeroout() because we don't have support for discard or write_same in PMEM. This will send zero page BIOs to the PMEM driver, which will do the zeroing as normal writes.