From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 834EB361DC4 for ; Tue, 20 Jan 2026 12:49:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768913353; cv=none; b=MjQ9n26aK4+usfiBnTYjmNzTjea2rSGxwjYnq72q48JLtdFXEAJ+qA5xBsCqzKvn+tixhxKB76nDcn0HONkPo+ZPUMgQ6sGZSVPV2vyC2OPukuYLp1+Gl/sd78YnmWOMPTW0LBN1GnyXYKO7HsCcaZYSpHrCRAaXcnXfGNL1EHs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768913353; c=relaxed/simple; bh=Y44ejQU4aMrfo1rZA+vU0Q9UQxBkm0QnXfJamSItof4=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=WGrjIKDpmTACLoFVh4ZdAqGJksnDdpOq46Hycp6mrFheGVyULXF/QlhpZhgdo0P4woSad9V+JhYchN7zGgltxttYi1GiwoOWNcRvL6AeKQbnZAvb+RVfGHQH1N2CV+MXVK3Nc8EXiHWmemeqUEZ8C9vAq9PPyS5uZy4TEW2/SoQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gorMvPie; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gorMvPie" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3AF59C16AAE; Tue, 20 Jan 2026 12:49:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768913353; bh=Y44ejQU4aMrfo1rZA+vU0Q9UQxBkm0QnXfJamSItof4=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=gorMvPiehvSVl3t6egCUmqtYtRDPRFwUC91WghLg9mp2iDeHmRMnSHNGJegbV3DPw xVp3y0PCQcc8a9IxhkQ/w/z1vsglfsVSnHY22cc4S36TZCnzdRYep4wRHqk4l4r+oy yCRY7wfbeiNAFNb/Hf54UDS6eqPWTKw4c6Q6b8wCqmm8n6X3M1RC8nS33lyEgSt5nH 1FBPb/SkrfNtOXBrgo4qPPkYKYh8pY6ZIseJUr/txE9eMHpYRvWVO1UYViUbInpy0e HJ9apYRsjMhqwCB/bm01qYJ9rTt6PU3fpz8xcO5ITnROhBJG3Ow5hFXOtpQGXEJNNn KfukkPW75Ed8w== Message-ID: <643e61a6-3539-492d-89d0-6e0ad918eccf@kernel.org> Date: Tue, 20 Jan 2026 20:49:11 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, jaegeuk@kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid f2fs_map_blocks() for consecutive holes in readpages To: Nanzhe Zhao References: <20260112013320.8028-1-chao@kernel.org> <5e888451-228e-41e5-ada7-a22a61cb84dd@126.com> <32fa7311-0393-4e71-a927-3c502e40efd8@kernel.org> <6d6b3bad.5f72.19bd535bd6d.Coremail.nzzhao@126.com> <7489ce81.333.19bd8ca5df6.Coremail.nzzhao@126.com> Content-Language: en-US From: Chao Yu In-Reply-To: <7489ce81.333.19bd8ca5df6.Coremail.nzzhao@126.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Nanzhe, On 1/20/2026 8:24 AM, Nanzhe Zhao wrote: > Hi Chao: > At 2026-01-19 21:44:48, "Chao Yu" wrote: >> >> I guess f2fs_map_no_dnode() will update map->m_next_pgofs to pgofs of next >> potential valid dnode. >> >> Thanks, >> > > I guess we were discussing the cases that f2fs_get_dnode_of_data won't return > -ENOENT in f2fs_map_blocks but dn.blkaddr is still NULL_ADDR or NEW_ADDR ? I may misunderstand your question at first place, sorry about that. > > I think I might understand the intention behind your repeated emphasis on the > f2fs_map_no_dnode case?  Are you saying that, on F2FS, the vast majority of sparse > files fall into holes where the dnode hasn't been allocated at all, and that within the > dnode the blkaddr values NULL_ADDR and NEW_ADDR—especially the latter on the read path > —are relatively uncommon? Actually, no, we'd better investigate into details of hole data pattern in device to see whether there are 1) more small holes in dnode (NULL_ADDR/NEW_ADDR case) or 2) there are more large hole in {di,i}dnode, do you have free slot to check that? :) Thanks, > > Thanks, > Nanzhe Zhao