From: Eric Sandeen Subject: Re: [PATCH v2 2/2] ext4: Ignore a stripe width of 1 Date: Fri, 15 Jul 2011 16:47:10 -0500 Message-ID: <4E20B55E.9080908@redhat.com> References: <1310766115-4164-1-git-send-email-dehrenberg@google.com> <1310766115-4164-2-git-send-email-dehrenberg@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Theodore Ts'o" , Andreas Dilger , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org To: Dan Ehrenberg Return-path: Received: from mx1.redhat.com ([209.132.183.28]:44054 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751395Ab1GOVrQ (ORCPT ); Fri, 15 Jul 2011 17:47:16 -0400 In-Reply-To: <1310766115-4164-2-git-send-email-dehrenberg@google.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 7/15/11 4:41 PM, Dan Ehrenberg wrote: > If the stripe width was set to 1, then this patch will ignore > that stripe width and ext4 will act as if the stripe width > were 0 with respect to optimizing allocations. > > Signed-off-by: Dan Ehrenberg Thanks, I think this makes sense. Reviewed-by: Eric Sandeen > --- > fs/ext4/super.c | 22 ++++++++++++++++------ > 1 files changed, 16 insertions(+), 6 deletions(-) > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 9ea71aa..0a3745b 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -2383,17 +2383,27 @@ static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi) > unsigned long stride = le16_to_cpu(sbi->s_es->s_raid_stride); > unsigned long stripe_width = > le32_to_cpu(sbi->s_es->s_raid_stripe_width); > + int ret; > > if (sbi->s_stripe && sbi->s_stripe <= sbi->s_blocks_per_group) > - return sbi->s_stripe; > + ret = sbi->s_stripe; > > - if (stripe_width <= sbi->s_blocks_per_group) > - return stripe_width; > + else if (stripe_width <= sbi->s_blocks_per_group) > + ret = stripe_width; > > - if (stride <= sbi->s_blocks_per_group) > - return stride; > + else if (stride <= sbi->s_blocks_per_group) > + ret = stride; > + else > + ret = 0; > > - return 0; > + /* > + * If the stripe width is 1, this makes no sense and > + * we set it to 0 to turn off stripe handling code. > + */ > + if (ret <= 1) > + ret = 0; > + > + return ret; > } > > /* sysfs supprt */