From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Moyer Subject: Re: [RFC] Draft Linux kernel interfaces for ZBC drives Date: Mon, 03 Feb 2014 16:01:15 -0500 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org To: "Theodore Ts'o" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:30301 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753168AbaBCVBW (ORCPT ); Mon, 3 Feb 2014 16:01:22 -0500 In-Reply-To: (Theodore Ts'o's message of "Fri, 31 Jan 2014 00:38:22 -0500") Sender: linux-fsdevel-owner@vger.kernel.org List-ID: "Theodore Ts'o" writes: > * We can also further shrink the structure by removing the > * z_checkpoint_offset element, since most of the time > * z_write_ptr_offset and z_checkpoint_offset will be the same. The > * only time they will be different is after a write is interrupted > * via an unexpected power removal This may fall into the nit-picking category, but at runtime I'd expect the write pointer and the checkpoint lba to be different more often than not, unless you're doing all FUA writes, or are issuing flushes after every write. After a power loss event, do we know what READ will return when you try to read between the checkpoint lba and the write pointer? I didn't see that in the linked specification, and I think it's important to know. Cheers, Jeff