From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=awAR=OE=lists.ozlabs.org=linux-erofs-bounces+linux-erofs=archiver.kernel.org@kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
X-Spam-Level: 
X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,
	HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH,
	MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY
	autolearn=unavailable autolearn_force=no version=3.4.0
Received: from mail.kernel.org (mail.kernel.org [198.145.29.99])
	by smtp.lore.kernel.org (Postfix) with ESMTP id D11A2C433F5
	for <linux-erofs@archiver.kernel.org>; Tue, 14 Sep 2021 04:37:49 +0000 (UTC)
Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by mail.kernel.org (Postfix) with ESMTPS id DF95F61130
	for <linux-erofs@archiver.kernel.org>; Tue, 14 Sep 2021 04:37:48 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org DF95F61130
Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com
Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.ozlabs.org
Received: from boromir.ozlabs.org (localhost [IPv6:::1])
	by lists.ozlabs.org (Postfix) with ESMTP id 4H7rDq4Jh2z2yPy
	for <linux-erofs@archiver.kernel.org>; Tue, 14 Sep 2021 14:37:47 +1000 (AEST)
Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized)
 smtp.mailfrom=linux.alibaba.com (client-ip=115.124.30.42;
 helo=out30-42.freemail.mail.aliyun.com;
 envelope-from=hsiangkao@linux.alibaba.com; receiver=<UNKNOWN>)
Received: from out30-42.freemail.mail.aliyun.com
 (out30-42.freemail.mail.aliyun.com [115.124.30.42])
 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
 key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256)
 (No client certificate requested)
 by lists.ozlabs.org (Postfix) with ESMTPS id 4H7rDg4Fnxz2yHb
 for <linux-erofs@lists.ozlabs.org>; Tue, 14 Sep 2021 14:37:34 +1000 (AEST)
X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R301e4; CH=green; DM=||false|;
 DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=alimailimapcm10staff010182156082;
 MF=hsiangkao@linux.alibaba.com; NM=1; PH=DS; RN=8; SR=0;
 TI=SMTPD_---0UoKZg15_1631594234; 
Received: from B-P7TQMD6M-0146.local(mailfrom:hsiangkao@linux.alibaba.com
 fp:SMTPD_---0UoKZg15_1631594234) by smtp.aliyun-inc.com(127.0.0.1);
 Tue, 14 Sep 2021 12:37:16 +0800
Date: Tue, 14 Sep 2021 12:37:14 +0800
From: Gao Xiang <hsiangkao@linux.alibaba.com>
To: Yue Hu <zbestahu@gmail.com>
Subject: Re: [PATCH] erofs: fix compacted_2b if compacted_4b_initial > totalidx
Message-ID: <YUAm+kOdKcCzgcEy@B-P7TQMD6M-0146.local>
References: <20210914035915.1190-1-zbestahu@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <20210914035915.1190-1-zbestahu@gmail.com>
X-BeenThere: linux-erofs@lists.ozlabs.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Development of Linux EROFS file system <linux-erofs.lists.ozlabs.org>
List-Unsubscribe: <https://lists.ozlabs.org/options/linux-erofs>,
 <mailto:linux-erofs-request@lists.ozlabs.org?subject=unsubscribe>
List-Archive: <http://lists.ozlabs.org/pipermail/linux-erofs/>
List-Post: <mailto:linux-erofs@lists.ozlabs.org>
List-Help: <mailto:linux-erofs-request@lists.ozlabs.org?subject=help>
List-Subscribe: <https://lists.ozlabs.org/listinfo/linux-erofs>,
 <mailto:linux-erofs-request@lists.ozlabs.org?subject=subscribe>
Cc: linux-kernel@vger.kernel.org, zbestahu@163.com, huyue2@yulong.com,
 linux-erofs@lists.ozlabs.org, zhangwen@yulong.com
Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org
Sender: "Linux-erofs"
 <linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org>

On Tue, Sep 14, 2021 at 11:59:15AM +0800, Yue Hu wrote:
> From: Yue Hu <huyue2@yulong.com>
> 
> Currently, the whole indexes will only be compacted 4B if
> compacted_4b_initial > totalidx. So, the calculated compacted_2b
> is worthless for that case. It may waste CPU resources.
> 
> No need to update compacted_4b_initial as mkfs since it's used to
> fulfill the alignment of the 1st compacted_2b pack and would handle
> the case above.
> 
> We also need to clarify compacted_4b_end here. It's used for the
> last lclusters which aren't fitted in the previous compacted_2b
> packs.
> 
> Some messages are from Xiang.
> 
> Signed-off-by: Yue Hu <huyue2@yulong.com>

Looks good to me,
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>

(although I think the subject title would be better changed into
 "clear compacted_2b if compacted_4b_initial > totalidx"
 since 'fix'-likewise words could trigger some AI bot for stable
 kernel backporting..)

Thanks,
Gao Xiang

> ---
>  fs/erofs/zmap.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
> index 9fb98d8..aeed404 100644
> --- a/fs/erofs/zmap.c
> +++ b/fs/erofs/zmap.c
> @@ -369,7 +369,8 @@ static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
>  	if (compacted_4b_initial == 32 / 4)
>  		compacted_4b_initial = 0;
>  
> -	if (vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B)
> +	if ((vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B) &&
> +	    compacted_4b_initial <= totalidx) {
>  		compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
>  	else
>  		compacted_2b = 0;
> -- 
> 1.9.1