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 20D28238166; Wed, 4 Mar 2026 14:41:23 +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=1772635285; cv=none; b=MgwB3IE6rlKneF0GJoIgdIPVuUzAxpcU9erP1w9IVvEOAagYqT8azfgi7xoct3YToC5X0SWISjMMWaOEMLiT77nt0Qoca6Wak3Yo+T0JxBQ/zngxYMgrbbrafq6QuiugTCTS4nqXYKNGb8FrIJ94cMdv9ZgsZVf7LT0yAdDKqrQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772635285; c=relaxed/simple; bh=JHhe0b5uRCKPquKmKU3yU0f4u1yAgujqMlLfOipat70=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HASmiUx1RBy9HjrLKUgx2pMj7dOzYHtCY+NMSjoLbBKn5te8TlgCzndcoEU14bS/3R4DFvAL5Rm7yo1myUz6faPE6DcWbIgOm3kN0KinNjK0lrX2xXxBmyw8sFLdsv8/NSY+QT9bFhj1lvZqYZqGkdrLtQ1leUbhkz1zWHP0TIU= 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=mKMmQUcw; 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="mKMmQUcw" 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=CEBxN2sxgSUGncdU2S40J1gB4jfFBcffVwdcttPbgjY=; b=mKMmQUcwp+LppXXThRDay4A7qg xJqm1mSse/KAY9qnEiZcHRNaE7SrU+mBeznVnBiGNNahXNScCRdNMctyYT1AEgipUsrUux7WCt3Is lhL8XcBKtYgq1aq0NJu1YylM8obniSaez5kgYymqZa+CvshgM3a23kZgw+IvvIMFjglMG8wJgh40f dPlLYcYxmzdNumQej64RMvUGL1TlT1EXSenlhr68NKB87E1+JlteOAEl0aUnFgu8VQAjBsWJUdmWz qDzrL3iqRVjhLBTE2GMuK6c3zBFlTZ14/isdHNQzOd+QyJK+owTcRcW8uD9qZ5oyb3tVVBPt2Uo/8 RTYaTxMA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vxnPf-0000000HQmR-0jaG; Wed, 04 Mar 2026 14:41:23 +0000 Date: Wed, 4 Mar 2026 06:41:23 -0800 From: Christoph Hellwig To: Brian Foster Cc: Christoph Hellwig , linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org Subject: Re: [PATCH v2 1/5] iomap, xfs: lift zero range hole mapping flush into xfs Message-ID: References: <20260129155028.141110-1-bfoster@redhat.com> <20260129155028.141110-2-bfoster@redhat.com> Precedence: bulk X-Mailing-List: linux-xfs@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 Wed, Mar 04, 2026 at 09:17:33AM -0500, Brian Foster wrote: > I tested the change below but it ended up failing xfs/131. Some fast and > loose (i.e. LLM assisted) trace analysis suggests the issue is that this > particular situation is racy. I.e., we write to a sparse file range and > add COW fork dellaloc, writeback kicks in and drops the delalloc > mapping, then zeroing occurs over said range and finds holes in both > forks, then zone I/O completion occurs and maps blocks into the data > fork. Yes, that can happen. But the folio will be locked or have the writeback bit set over that whole period, so I can't see how writeback can actually race with that?