From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 EE7292EA162; Fri, 27 Jun 2025 17:03:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751043801; cv=none; b=NeqikWzcwaAqID9vqqUSCMRl7hPYdJID+S+8F+fTJHY5/vXJ/AxdxBMhle2uMcTtWIUbNNIxnlKTUVEpeP3rQwSmPsIbg+tDp6UjIq+LRCZYQem1wzZOac9IKSBretYgLdt97LvVAgcgyi/9YQefIrCTqxTFVrokp2ixzVSkHJw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751043801; c=relaxed/simple; bh=6iU4sKtqulwtJbHdtTjfBW2WtHCU3a8mQLkMyO716dQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=uAj1DxKr/1aSg59b6nOevskiOwY1cu23NU98E51YUyvIaKZgR619ChKkPRPzefBUi/4rNWo05ZhUO9kuvJDPwiB7QDxFXMsStTBCjl6giP/E4Bui+Cw3GdHXXmTbQQfeA1rLFFMHi6cQaym583rk7tF1DO8VrKSbZlG8Ldg/Gxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=lLKFhWE7; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="lLKFhWE7" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=BX8yP699mQd1hqQWYrl2/cTWYSKTaQhOnRx2XR4O0nI=; b=lLKFhWE7lu96o6X4WT3tH4Sf1O oFn+aopDUWdGLcdZZzN4QfYf4S6XDwKRYHArQn5ap3m58Et87mT4Ayt6ydcfEgKSJk9PEFzYHQGW/ JMPMcvwErhnhXiakaH6uPHmYcq+T3F3YwECBJHYqoUiNPo9ymCBd1Ib/d9+WGAmCO0GI/fl3FtOmv +toLcyd8ZL6SW5pWju0H9RRNwMPb2ngciRiSRQuHslvf32Vy10QFJC1mkVGwPE+K86H2nT+LgoeKL 1nQzjkHMiGrUvnzfn32qPmJoVD+pIIBdxrgVJB1unlnK8fQDHJ9XR/SU0LsqA909wugZbwr1k3AbM 5BCG5tNw==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uVCTl-0000000EZN4-26cY; Fri, 27 Jun 2025 17:03:09 +0000 Date: Fri, 27 Jun 2025 18:03:09 +0100 From: Matthew Wilcox To: =?utf-8?B?6ZmI5rab5rab?= Taotao Chen Cc: "tytso@mit.edu" , "hch@infradead.org" , "adilger.kernel@dilger.ca" , "brauner@kernel.org" , "jani.nikula@linux.intel.com" , "rodrigo.vivi@intel.com" , "tursulin@ursulin.net" , "airlied@gmail.com" , "linux-fsdevel@vger.kernel.org" , "linux-ext4@vger.kernel.org" , "linux-block@vger.kernel.org" , "intel-gfx@lists.freedesktop.org" , "dri-devel@lists.freedesktop.org" , "linux-mm@kvack.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "chentao325@qq.com" , "frank.li@vivo.com" Subject: Re: [PATCH v3 4/4] ext4: support uncached buffered I/O Message-ID: References: <20250627110257.1870826-1-chentaotao@didiglobal.com> <20250627110257.1870826-5-chentaotao@didiglobal.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250627110257.1870826-5-chentaotao@didiglobal.com> On Fri, Jun 27, 2025 at 11:03:13AM +0000, 陈涛涛 Taotao Chen wrote: > +++ b/fs/ext4/inode.c > @@ -1270,6 +1270,9 @@ static int ext4_write_begin(const struct kiocb *iocb, > if (unlikely(ret)) > return ret; > > + if (iocb->ki_flags & IOCB_DONTCACHE) > + fgp |= FGP_DONTCACHE; I think this needs to be: if (iocb && iocb->ki_flags & IOCB_DONTCACHE) because it's legit to call write_begin with a NULL argument. The 'file' was always an optional argument, and we should preserve that optionality with this transformation. I wonder if it's worth abstracting some of this boilerplate. Something like: struct folio *write_begin_get_folio(iocb, mapping, index, len) { fgf_t fgflags = FGP_WRITEBEGIN; if (iocb && iocb->ki_flags & IOCB_DONTCACHE) fgflags |= FGP_DONTCACHE; fgflags |= fgf_set_order(len); return __filemap_get_folio(mapping, index, fgflags, mapping_gfp_mask(mapping)); }