From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 2004C2DEA75 for ; Tue, 11 Nov 2025 09:30:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762853443; cv=none; b=MZmbNWMY5+WgDSfFyVTlGwTo8WNPhGw8TXPU5f5D4QXEj3FTjRYDG3BpbqEfAc++pTE6d4A/wip9RPKYDLjknC7Vux1Fs3U9S7cFblA+U87vabm2VfLJmYJala/JnbnZH4jQgPUcmSkJEGMJBTgUaRfdnqo9WubNj41wFbjrBsQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762853443; c=relaxed/simple; bh=Pl1O2aK3f7SCaGDeT7WJAGlIhfq/1h/E92nrNOSzuQg=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=WyGgMky4gFpQvVY8zCcHd+fDHaFP4FSsBFnweQUa/ruwsgAJNb+O2FrjNsmsMcyXbkzzmc8QbeVDc+ApQ+mgl2CTAQlemOxgz2n784tnZ9WohcMllZdgeZhefLLBw9N5RcWXQEC3OQRvkTqdEvFsG2VFjVOjTbUlOQsteb24s5k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Wdh3kZgF; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Wdh3kZgF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1762853441; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=yfmBGDXPeWaCMkaY7wTnRtorjcH8kduY0v5fCrRVaTM=; b=Wdh3kZgFgOKNfhOWCuV/LoSYSP9o5ZF5JC/YdUrYnd6UtVqf/k5+z0JOO62YBWRYByfXZK MEp/1BCTCvi1mGiNb2wJF8iWcumMOiuw5VaDkpsZRs55wP7XnYzamhXhtcj5S8UGtCYiwp cn+74/CyR1rwiNr5SYmx/CAAKJ9rXms= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-183-h4Aesh9ZO8SI9YmjnIdt6w-1; Tue, 11 Nov 2025 04:30:37 -0500 X-MC-Unique: h4Aesh9ZO8SI9YmjnIdt6w-1 X-Mimecast-MFC-AGG-ID: h4Aesh9ZO8SI9YmjnIdt6w_1762853436 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id ED8F318002CF; Tue, 11 Nov 2025 09:30:35 +0000 (UTC) Received: from fweimer-oldenburg.csb.redhat.com (unknown [10.45.225.58]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A3AA530044E5; Tue, 11 Nov 2025 09:30:31 +0000 (UTC) From: Florian Weimer To: Dave Chinner Cc: Christoph Hellwig , Matthew Wilcox , Hans Holmberg , linux-xfs@vger.kernel.org, Carlos Maiolino , "Darrick J . Wong" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, libc-alpha@sourceware.org Subject: Re: [RFC] xfs: fake fallocate success for always CoW inodes In-Reply-To: (Dave Chinner's message of "Tue, 11 Nov 2025 08:33:34 +1100") References: <20251106133530.12927-1-hans.holmberg@wdc.com> <20251106135212.GA10477@lst.de> <20251106170501.GA25601@lst.de> <878qgg4sh1.fsf@mid.deneb.enyo.de> <20251110093701.GB22674@lst.de> Date: Tue, 11 Nov 2025 10:30:28 +0100 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 * Dave Chinner: > I don't see how a glibc posix_fallocate() fallback that does a > non-desctructive truncate up though some new interface is any better > than just having the filesystem implement ALLOCATE_RANGE without the > ENOSPC guarantees in the first place? It's better because you don't have to get consensus among all file system developers that implementing ALLOCATE_RANGE as a non-destructive truncate is acceptable. Even it means that future writes to the range can fail with ENOSPC, contrary to what POSIX requires for posix_fallocate. Thanks, Florian