From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.cs.ucla.edu (mail.cs.ucla.edu [131.179.128.66]) (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 3826E15B542 for ; Mon, 29 Jul 2024 17:23:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=131.179.128.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722273798; cv=none; b=X+NjV5ONLQ4mWb4dv7aOgeasx0Sc4V+tmE7OnirVtKLMFOh/HU0n5qCGLttx+bVMOBt0oZuBsGl35yNuq8j55bMjoo/RZobv8MLM95zIgiQKooczsDe5qJnezypfTHjv5lkXderWCqfV414L7MOUofAdcP3RHO7YCv8lTbwZxZs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722273798; c=relaxed/simple; bh=Ok8zBeQ4hJwhTpKdNivnCdL3jiToMB2Z0syXSl0Exzk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=l/u89Ac1McHXjhXdAyWkTaSbtECjDSm8H3+4p9vmEaWVOX8lweU/Zc6aS9fGnjdJWHRPZfngO7o38PeR8DSKK21z++nzF0R84DPDzw2GHMGr3xL/flhBxG/EN9m02B8glyq2+RFIFWBEl20Zs43jRCMkTM75+8q1c5FyJ9iARps= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=cs.ucla.edu; spf=pass smtp.mailfrom=cs.ucla.edu; dkim=pass (2048-bit key) header.d=cs.ucla.edu header.i=@cs.ucla.edu header.b=TVl6AUMh; arc=none smtp.client-ip=131.179.128.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=cs.ucla.edu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=cs.ucla.edu Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=cs.ucla.edu header.i=@cs.ucla.edu header.b="TVl6AUMh" Received: from localhost (localhost [127.0.0.1]) by mail.cs.ucla.edu (Postfix) with ESMTP id 1E3613C011BD4; Mon, 29 Jul 2024 10:23:10 -0700 (PDT) Received: from mail.cs.ucla.edu ([127.0.0.1]) by localhost (mail.cs.ucla.edu [127.0.0.1]) (amavis, port 10032) with ESMTP id Xdfg4zSHVV5k; Mon, 29 Jul 2024 10:23:09 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by mail.cs.ucla.edu (Postfix) with ESMTP id BB28C3C011BD8; Mon, 29 Jul 2024 10:23:09 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.cs.ucla.edu BB28C3C011BD8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cs.ucla.edu; s=9D0B346E-2AEB-11ED-9476-E14B719DCE6C; t=1722273789; bh=Kv5fMYPSuWGayO+d9BiKB36G/fC5C4qkwFAB4LiTGEM=; h=Message-ID:Date:MIME-Version:To:From; b=TVl6AUMhX9tIrbA9Jj0yPjd4VvZFBbYDpUmuJ4LnYwx0L/P5HeeJJoUcl5zp6sQ2G bVnnf6knyvJPEdzIDueVXrkeO/kY9JfvToce3sPiU9THAteVum4Q1NE6aZ4IntTzY0 e1kewErEJ32m4uIFeMCRJBBDKTfDU8WzDFmJqaUcQyRBjsrgG4CRHEfqY08t2wcyEh XSDLDrQTXEek9adq7m5PPh0NF6oWU9hDlDLuGWM/6zUe/fyBihsVzGplsoMi8F0z7L HGo9OwgbTs1SZukzh015gwYaX0rnWAFPxE2S+F9HPkkucFCRkbCGqaJI/V5CSUGyGH KCRWHgv5gcXJQ== X-Virus-Scanned: amavis at mail.cs.ucla.edu Received: from mail.cs.ucla.edu ([127.0.0.1]) by localhost (mail.cs.ucla.edu [127.0.0.1]) (amavis, port 10026) with ESMTP id bOGFQ9bM6_9G; Mon, 29 Jul 2024 10:23:09 -0700 (PDT) Received: from [192.168.254.12] (unknown [47.154.17.165]) by mail.cs.ucla.edu (Postfix) with ESMTPSA id 989A43C011BC5; Mon, 29 Jul 2024 10:23:09 -0700 (PDT) Message-ID: <91e405eb-0f55-4ffc-a01d-660e2e5d0b84@cs.ucla.edu> Date: Mon, 29 Jul 2024 10:23:09 -0700 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: posix_fallocate behavior in glibc To: Christoph Hellwig Cc: Trond Myklebust , libc-alpha@sourceware.org, linux-fsdevel@vger.kernel.org References: <20240729160951.GA30183@lst.de> Content-Language: en-US From: Paul Eggert Organization: UCLA Computer Science Department In-Reply-To: <20240729160951.GA30183@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024-07-29 09:09, Christoph Hellwig wrote: > How can we get rid of this glibc fallback that turns the implementations > non-conformant and increases write amplication for no good reason? The simplest solution would be to remove the broken fallback in glibc. A more conservative possibility would be to use the fallback only on file system types that lack native fallocate and where the fallback is known to work (which are they?). Perhaps you could propose a patch along either line.