From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dkim2.fusionio.com ([66.114.96.54]:47424 "EHLO dkim2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756171Ab3DYSsh (ORCPT ); Thu, 25 Apr 2013 14:48:37 -0400 Received: from mx1.fusionio.com (unknown [10.101.1.160]) by dkim2.fusionio.com (Postfix) with ESMTP id 2C5209A0699 for ; Thu, 25 Apr 2013 12:48:36 -0600 (MDT) Date: Thu, 25 Apr 2013 14:48:33 -0400 From: Josef Bacik To: Liu Bo CC: "linux-btrfs@vger.kernel.org" Subject: Re: [PATCH] Btrfs: improve the loop of scrub_stripe Message-ID: <20130425184833.GK2631@localhost.localdomain> References: <1366304095-3206-1-git-send-email-bo.li.liu@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: <1366304095-3206-1-git-send-email-bo.li.liu@oracle.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Thu, Apr 18, 2013 at 10:54:55AM -0600, Liu Bo wrote: > 1) Right now scrub_stripe() is looping in some unnecessary cases: > * when the found extent item's objectid has been out of the dev extent's range > but we haven't finish scanning all the range within the dev extent > * when all the items has been processed but we haven't finish scanning all the > range within the dev extent > > In both cases, we can just finish the loop to save costs. > > 2) Besides, when the found extent item's length is larger than the stripe len(64k), > we don't have to release the path and search again as it'll get at the same key > used in the last loop, we can instead increase the logical cursor in place till > all space of the extent is scanned. > > 3) And we use 0 as the key's offset to search btree, then get to previous item > to find a smaller item, and again have to move to the next one to get the right > item. Setting offset=-1 and previous_item() is the correct way. > > 4) As we won't find any checksum at offset unless this 'offset' is in a data > extent, we can just find checksum when we're really going to scrub an extent. > > Signed-off-by: Liu Bo A big chunk of this doesn't apply to btrfs-next and I don't feel comfortable manually applying it, please rebase and resend. Thanks, Josef