From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id C505621107832 for ; Thu, 30 Aug 2018 12:53:36 -0700 (PDT) From: Jeff Moyer Subject: Re: Snapshot target and DAX-capable devices References: <20180827160744.GE4002@quack2.suse.cz> <20180828075025.GA17756@quack2.suse.cz> <20180828175630.GA1197@redhat.com> <20180830093028.GC1767@quack2.suse.cz> <20180830184907.GA14867@redhat.com> Date: Thu, 30 Aug 2018 15:53:31 -0400 In-Reply-To: (Mikulas Patocka's message of "Thu, 30 Aug 2018 15:47:32 -0400 (EDT)") Message-ID: MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Mikulas Patocka Cc: Jan Kara , Mike Snitzer , "linux-nvdimm@lists.01.org" , "dm-devel@redhat.com" , "linux-fsdevel@vger.kernel.org" List-ID: Mikulas Patocka writes: > On Thu, 30 Aug 2018, Jeff Moyer wrote: > >> Mike Snitzer writes: >> >> > Until we properly add DAX support to dm-snapshot I'm afraid we really do >> > need to tolerate this "regression". Since reality is the original >> > support for snapshot of a DAX DM device never worked in a robust way. >> >> Agreed. >> >> -Jeff > > You can't support dax on snapshot - if someone maps a block and the block > needs to be moved, then what? That's exactly the point I brought up in my reply to Jan. You'd have to unmap all mappings of the page/block. -Jeff _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx3-rdu2.redhat.com ([66.187.233.73]:46354 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727203AbeH3X5Y (ORCPT ); Thu, 30 Aug 2018 19:57:24 -0400 From: Jeff Moyer To: Mikulas Patocka Cc: Mike Snitzer , Jan Kara , "Kani\, Toshi" , "linux-nvdimm\@lists.01.org" , "dm-devel\@redhat.com" , "linux-fsdevel\@vger.kernel.org" , "ross.zwisler\@linux.intel.com" , "dan.j.williams\@intel.com" Subject: Re: Snapshot target and DAX-capable devices References: <20180827160744.GE4002@quack2.suse.cz> <20180828075025.GA17756@quack2.suse.cz> <20180828175630.GA1197@redhat.com> <20180830093028.GC1767@quack2.suse.cz> <20180830184907.GA14867@redhat.com> Date: Thu, 30 Aug 2018 15:53:31 -0400 In-Reply-To: (Mikulas Patocka's message of "Thu, 30 Aug 2018 15:47:32 -0400 (EDT)") Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Mikulas Patocka writes: > On Thu, 30 Aug 2018, Jeff Moyer wrote: > >> Mike Snitzer writes: >> >> > Until we properly add DAX support to dm-snapshot I'm afraid we really do >> > need to tolerate this "regression". Since reality is the original >> > support for snapshot of a DAX DM device never worked in a robust way. >> >> Agreed. >> >> -Jeff > > You can't support dax on snapshot - if someone maps a block and the block > needs to be moved, then what? That's exactly the point I brought up in my reply to Jan. You'd have to unmap all mappings of the page/block. -Jeff From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Moyer Subject: Re: Snapshot target and DAX-capable devices Date: Thu, 30 Aug 2018 15:53:31 -0400 Message-ID: References: <20180827160744.GE4002@quack2.suse.cz> <20180828075025.GA17756@quack2.suse.cz> <20180828175630.GA1197@redhat.com> <20180830093028.GC1767@quack2.suse.cz> <20180830184907.GA14867@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: (Mikulas Patocka's message of "Thu, 30 Aug 2018 15:47:32 -0400 (EDT)") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: Mikulas Patocka Cc: Jan Kara , Mike Snitzer , "linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org" , "dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , "linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: dm-devel.ids Mikulas Patocka writes: > On Thu, 30 Aug 2018, Jeff Moyer wrote: > >> Mike Snitzer writes: >> >> > Until we properly add DAX support to dm-snapshot I'm afraid we really do >> > need to tolerate this "regression". Since reality is the original >> > support for snapshot of a DAX DM device never worked in a robust way. >> >> Agreed. >> >> -Jeff > > You can't support dax on snapshot - if someone maps a block and the block > needs to be moved, then what? That's exactly the point I brought up in my reply to Jan. You'd have to unmap all mappings of the page/block. -Jeff