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?