From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 58E112F549F for ; Mon, 20 Jul 2026 08:04:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784534646; cv=none; b=WG9zgmWJtqow41gfLvwKBbqZNKrQ/FKNYNLreXUfg12qlSAYhUmQVGwQ6a1HeWlwrqayR5/xRhE4lFM/vN0EK1bwXXetx+pNt5KPJzCA7bj4qVgrJABa6czo0zKIqTNeJd340Cw7M2aYgtzNqV0karx8y22WPfCgZYEDxkGIJ/U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784534646; c=relaxed/simple; bh=BQ1gp9p3aYvAui7EH5ROM9JM3ievSj52ezm/pEldpXU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Swb7yJ3Y+IrGv4YPDLnjsKpSGqY3TQy+elKirwf1nZH0QxkVY748hPEMtZkihNS+4XJ1Ut/+27P1Pe9Mys8P3ZB8UXWAc3+4r6gidjwlJwG4xtBeMSgAeWsUVdMFsm1lpTvsIs0IxICFYYHfKOaMtlgrDFAq4qPshufg6V7BLnc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=pjBU6g1b; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="pjBU6g1b" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+k/S57ilndGjoJss1cqjmQ22UwAd2c+Gg+Fclh9PZOU=; b=pjBU6g1bY/5CCKbkWnRO68c+lZ hN+mOASOwbENw9K3BviGH93pyvJIgn8pjfVKR5gDS2Sw8kVKSAw15MWDzUM1UsYVFOXB8lQOeKMT2 QeMk9wl83lEG/h3aKcExIlga32UzGiy+8fqX9cWEpht1MfzZokqHdm0ZVpeknqkkpiPSe19/Fg/GY GMueV8iBvh8MA8z2N8be60rj5R1yInaoG81s2GIzNDzBZ+R/LcccReOLXP2yKXacrzZmYGTCH5+zM GYz00WY02oSpeSDqGHwN5YpBDq7pJunwUxTxDH4muBcZgPtfsWUNv74RNayKJIAKZR4ZeaBGykASu AQ3YyU8g==; Received: from hch by bombadil.infradead.org with local (Exim 4.99.1 #2 (Red Hat Linux)) id 1wliyp-000000069mR-0zhX; Mon, 20 Jul 2026 08:04:03 +0000 Date: Mon, 20 Jul 2026 01:04:03 -0700 From: Christoph Hellwig To: Chao Yu Cc: Christoph Hellwig , Zorro Lang , Jan Prusakowski , linux-f2fs-devel@lists.sourceforge.net, fstests@vger.kernel.org, jaegeuk@kernel.org Subject: Re: [f2fs-dev] [PATCH] generic/064: allow 50 extents on F2FS after fcollapse Message-ID: References: <20260622070438.1542638-1-jprusakowski@google.com> Precedence: bulk X-Mailing-List: fstests@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Jun 30, 2026 at 08:09:19PM +0800, Chao Yu wrote: > > Let me explain it briefly, this is because f2fs has only one copy of reverse > mapping table (aka SSA), for any checkpointed data, we can not modify SSA info > directly during remap, otherwise, after sudden power-cut, we will suffer > inconsistent issue in between reverse mapping table and mapping table. So, f2fs > choose to rewrite for any checkpointed data. So looking at this explanation and the code, f2fs does not actually support COLLAPSE_RANGE at all, but emulates by doing a full data copy. What is the point of this and lying to the user that it supports and operation that isn't actually supported as the intended metadata only swizzle? 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 Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8CBB3C44515 for ; Mon, 20 Jul 2026 08:04:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.sourceforge.net; s=beta; h=Content-Transfer-Encoding:Content-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Subject:In-Reply-To:MIME-Version:References:Message-ID:To:From:Date:Sender: Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender :Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=+h7B5dC5yxEItbQfelUfi9pfVkJDzln+7evaUakSp6Q=; b=guwfoCXJn/9t1M6bzY6tdChF1q ts2I0u1+xf4G+OjR35VkxshgZLR3G0RrGHrxNBmAaVUanFH0gXhjYaP+TttPBUWCRgJcrFE1vTP9a hnDzrnv624QVKiq5T4rLEmeDW6Hjvbp4kDXOuoAGQgesBIKwGlPcD2kbc6klsWEJ8Zo8=; Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1wlizB-0005xr-Pa; Mon, 20 Jul 2026 08:04:23 +0000 Received: from [172.30.29.66] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1wliz3-0005tw-9W for linux-f2fs-devel@lists.sourceforge.net; Mon, 20 Jul 2026 08:04:15 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=In-Reply-To:Content-Type:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=+k/S57ilndGjoJss1cqjmQ22UwAd2c+Gg+Fclh9PZOU=; b=O54GgtZeNUFc2+tQy3FHfEw//X wVDD8csAhq6K1DTdj7CA6q/BCnOc3Iayxea9P6XRPpgaHi9GiwvsDfUmc4B9XKKl9SQISmTLnP9rb E875UcDPSEi8L1IoOKrg0ee7okeKp9gE6A1g0u9QJHiF+3MLwK/RkJQXt7sFTMMFSkP4=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To :From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=+k/S57ilndGjoJss1cqjmQ22UwAd2c+Gg+Fclh9PZOU=; b=QysoKRJyfaBuIQifH51S7gyqrp Sc2g3zxwcVrlg+LVCq8xYIkjfPi81LPIoxboZpg9iWG3FiAafAXWOIbWWx+CAwUvHzmblU+Qm6p2R jnaOfooDowY6pyEfqHIZ7EiEkAW/b86CV0BbVH3PyXkRmY9Bo7NA9fU0ptDmsIqU/q6Q=; Received: from bombadil.infradead.org ([198.137.202.133]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1wliyz-0001X0-UW for linux-f2fs-devel@lists.sourceforge.net; Mon, 20 Jul 2026 08:04:14 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+k/S57ilndGjoJss1cqjmQ22UwAd2c+Gg+Fclh9PZOU=; b=pjBU6g1bY/5CCKbkWnRO68c+lZ hN+mOASOwbENw9K3BviGH93pyvJIgn8pjfVKR5gDS2Sw8kVKSAw15MWDzUM1UsYVFOXB8lQOeKMT2 QeMk9wl83lEG/h3aKcExIlga32UzGiy+8fqX9cWEpht1MfzZokqHdm0ZVpeknqkkpiPSe19/Fg/GY GMueV8iBvh8MA8z2N8be60rj5R1yInaoG81s2GIzNDzBZ+R/LcccReOLXP2yKXacrzZmYGTCH5+zM GYz00WY02oSpeSDqGHwN5YpBDq7pJunwUxTxDH4muBcZgPtfsWUNv74RNayKJIAKZR4ZeaBGykASu AQ3YyU8g==; Received: from hch by bombadil.infradead.org with local (Exim 4.99.1 #2 (Red Hat Linux)) id 1wliyp-000000069mR-0zhX; Mon, 20 Jul 2026 08:04:03 +0000 Date: Mon, 20 Jul 2026 01:04:03 -0700 From: Christoph Hellwig To: Chao Yu Message-ID: References: <20260622070438.1542638-1-jprusakowski@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Headers-End: 1wliyz-0001X0-UW Subject: Re: [f2fs-dev] [PATCH] generic/064: allow 50 extents on F2FS after fcollapse X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Zorro Lang , fstests@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Christoph Hellwig , jaegeuk@kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Tue, Jun 30, 2026 at 08:09:19PM +0800, Chao Yu wrote: > > Let me explain it briefly, this is because f2fs has only one copy of reverse > mapping table (aka SSA), for any checkpointed data, we can not modify SSA info > directly during remap, otherwise, after sudden power-cut, we will suffer > inconsistent issue in between reverse mapping table and mapping table. So, f2fs > choose to rewrite for any checkpointed data. So looking at this explanation and the code, f2fs does not actually support COLLAPSE_RANGE at all, but emulates by doing a full data copy. What is the point of this and lying to the user that it supports and operation that isn't actually supported as the intended metadata only swizzle? _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel