From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 F3188C433EF for ; Sat, 4 Sep 2021 04:40:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D17C160F90 for ; Sat, 4 Sep 2021 04:40:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233024AbhIDEl2 (ORCPT ); Sat, 4 Sep 2021 00:41:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232141AbhIDEl1 (ORCPT ); Sat, 4 Sep 2021 00:41:27 -0400 Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0CAD4C061575 for ; Fri, 3 Sep 2021 21:40:26 -0700 (PDT) Received: by mail-lf1-x131.google.com with SMTP id s10so2290730lfr.11 for ; Fri, 03 Sep 2021 21:40:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dP+j4JXyDo34ICC3JmPP8rPqOyI1cAd3JzgpaFIRD4I=; b=jExnvpX8lFUG+gFgfft7gQUua/drCkukHXU314B7Yaw5h0DOnJPIyq1vOlCo4wHgWH IkTMCVnUwZUOsT1VCqfmOfzryoXk52iYIModjiklCYFwhO5PofuenJPYnTOO6RTAFz/p oRbH1lqc3K7JNqoAEaycoK9ux2QIgeeo9htBfCn12P2pJ4+wIMJyywsbnXpJbqAtJ2T0 BO6SG9vsDTU9GxRpc9MkMFfZMCyR9WDtsoaiwqutAbGbF6jGXtwywDt/jNp6yOQjmRAt bBN1K3f6pL3RyqdEWZYIwBEyl7IOeJj+3J5PScHpsrjpPiIv6TSfUN/yfx9I+FmsFOAz wtLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dP+j4JXyDo34ICC3JmPP8rPqOyI1cAd3JzgpaFIRD4I=; b=SO2804KpCwQMG1Umcaqd1uTBivPCsj2UU9STXviZgZ2c8D75mbZDJWPVVZzeYWZCFD DL5Sx2kXFRnnD6EkXQO6O0WXIGs1GZrMoMoP7O3czmdZtVj47olhl5Q9m09d9Pqx/oI3 BLCUMcBqP+dH08tJV1RXT2Nx4yiHNSFjyxBcze9/JgDgKwTJiem2AKBxQf4EfJaj0W7X jZ05lykJ9RAsW7kHBBhmqH1mK85FJ5aSJY9iEF3pDr54c3tfR18vO20Fka5uzCL6ngOH Hq5lSRfPl2dYsH5WnCpeeFd9hF6VIPvEYw/fDkN6bUuemDrHgDylv0M3psK0vsMxyqTu aTCw== X-Gm-Message-State: AOAM531LyqTjLBDzBHDkWhiR6Av3CB8o1tq2Ht2EGnMAp22EbTXDzR3e q7UoBEBjy08qrVp81baeKunK9As0u7MZL1gp2i5xMI+lDas= X-Google-Smtp-Source: ABdhPJxtE7a+pXHA9vv/DbRTQSMp2yIwkyjcLIa/2qvDD7Gt6Tv7i3FVAXf9SprNaomxYhPXYcEsQuyORGLdeKpzOjo= X-Received: by 2002:a05:6512:1189:: with SMTP id g9mr1825764lfr.26.1630730424284; Fri, 03 Sep 2021 21:40:24 -0700 (PDT) MIME-Version: 1.0 References: <20210902172404.3517626-1-daeho43@gmail.com> <9ab17089-accc-c3a3-a5dc-007fc4eeaa20@kernel.org> <8f8e4695-4062-60c4-0f91-2a1f6a5b0a11@kernel.org> In-Reply-To: <8f8e4695-4062-60c4-0f91-2a1f6a5b0a11@kernel.org> From: Daeho Jeong Date: Fri, 3 Sep 2021 21:40:13 -0700 Message-ID: Subject: Re: [f2fs-dev] [PATCH v4] f2fs: introduce fragment allocation mode mount option To: Chao Yu Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com, Daeho Jeong Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > As a per curseg field. > > > Maybe, we run into the same race condition issue you told before for > > fragment_remained_chunk. > > Could you clarify this more? > > e.g. > > F2FS_OPTION(sbi).fs_mode = FS_MODE_FRAGMENT_FIXED_BLK > fragment_chunk_size = 384 > fragment_hole_size = 384 > > When creating hole: > > - f2fs_allocate_data_block > - __refresh_next_blkoff > chunk locates in [0, 383] of current segment > seg->next_blkoff = 384 > sbi->fragment_remained_chunk = 0 > then we will reset sbi->fragment_remained_chunk to 384 > and move seg->next_blkoff forward to 768 (384 + 384) > - __has_curseg_space() returns false > - allocate_segment() allocates new current segment > > So, for such case that hole may cross two segments, hole size may be truncated > to left size of previous segment. First, sbi->fragment_remained_chunk should be seg->fragment_remained_chunk. I understand what you mean, so you mean we need to take the leftover "hole" size over to the next segment? In the example, the leftover hole size will be (384 - (512-384)). Do you want to take this over to the next segment?