From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794554908; b=kWwImVVq0SLhAc726rLPFS3lScSLBNxdsnRW1X63CreEcuRyESdC0mZ2L/xyfZjgHbGZ 7cB7GQfxRU/Qe9U3CLxqOb9LWIAQtsxzpKfBmrdRHGMa6p6oZt4olGBY2V1BsPN7kIZis 5zQKLFeqiFAmPYCQzkBUnzhjpKHnQl6svdfMmCUi5YtoLGNZbxZO9yC7jW+FJnJC7CYgp w36biz7bzODgdRMV0wxQOPL47GQ9b4zGwQvT/+biv9RAgpplXrSQFVMj5L0QcOJYs3vFl fMmmi0nAppt89S/boFxKTdQrY6Xit04j+4UQPGPRbEcKD1d1y4jy0ULQ+PK+gcDRLmw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794554908; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=/3Dt68gX+2smueLMVZ+hG5GjqXN4NOBsl+vEefgb44Q=; b=hZdNY1Dbzi0lY/U8g7oV+tEu9tRcGEtWU7eaTZBb/WWZ+b95PnD7bEhqiz6Ui4P/WZRo UxbZauJ5UIz5l7ms5SWVRvYltEkI+C12qqjOGFCmI83VEsoQcXU+LDSDHQ+RilYqt8mZf jsXRWOS/zivdF09pcCwRJTyZZCCJGTjEe3BvxmBKzZgrwMZ+sp0qDiOBkaZH+F+FPDikj Snl3fSZ2suJ6A0wfSPLQ9pZxV84mHhpI243xPH8kamKNM1WMJQqaNN3Aem1U/n3QbQqKY ezCmePwbKqlsaqWyUMtyJWB9uh1+COZZO8stxiJleCqpUa01M5p2D/sle/KUX3WwEhA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="nLIPSk/s"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6FD94606A31C for ; Fri, 13 Nov 2026 07:28:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=nLIPSk/s Received: by smtp.kernel.org (Postfix) with ESMTPSA id D55651F000C4; Fri, 13 Nov 2026 07:28:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794554908; bh=/3Dt68gX+2smueLMVZ+hG5GjqXN4NOBsl+vEefgb44Q=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=nLIPSk/skF2AqWmLFJsympZMRl0Sohgqmlozo0cNworPjtSlyyR556zGYcqpaWwKT pMPt0RQWvv5jmJMcuLtlBJex7WLQmEskYFOyxDXRFwPIdRCou3KMxMDpzMS1wzL7Cx VM2K0BolzFiUeSWDBIF1NGIfCfJoP7btVcJFaSe+hoJnTFSZFaXoAxlPea8rHG/b6r uERwYEfIrlMSTwagftX0VlrJAPcRepYsongTnM0SErJqp0Vig/quRKJJYjmQA/hT/h XNsLVGCjLSDCi33nhz77t3B8pWIJCWb0wKooLfBwB55YVotkbInSBQQa9yUuHQcXVc HK9hOMs+vtMUw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v2 3/8] iomap: don't ask for a buffered fallback for dma-buf iterators Reply-To: sashiko-reviews@lists.linux.dev To: "Mengmeng Zhao" Cc: linux-ext4@vger.kernel.org, tytso@mit.edu In-Reply-To: <20261113070621.273953-4-mengmeng.zhao@linux.dev> References: <20261113070621.273953-1-mengmeng.zhao@linux.dev> <20261113070621.273953-4-mengmeng.zhao@linux.dev> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 13 Nov 2026 07:28:27 +0000 X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > From: Mengmeng Zhao >=20 > -ENOTBLK tells the caller to retry with buffered I/O. A dma-buf iterator > has no pages to copy, so the callers refuse that fallback, which would > turn the error into a successful transfer of zero bytes. >=20 > Report the reason instead: a busy folio becomes -EAGAIN, which the caller > can retry, any other invalidation failure keeps its error code, and > -ENOTBLK from ->iomap_begin() becomes -EOPNOTSUPP when nothing was > transferred. A partial direct I/O still reports its progress. Both > branches are reachable only through a file that opted into dma-buf I/O, > which ext4 does in the last patch. >=20 > Signed-off-by: Mengmeng Zhao > Signed-off-by: Li Wang Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261113070621.2739= 53-1-mengmeng.zhao@linux.dev?part=3D3