Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752011AbaLQIGR (ORCPT ); Wed, 17 Dec 2014 03:06:17 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:60126 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751673AbaLQIGP (ORCPT ); Wed, 17 Dec 2014 03:06:15 -0500 Date: Wed, 17 Dec 2014 00:06:10 -0800 From: Christoph Hellwig To: Omar Sandoval Cc: Christoph Hellwig , Jan Kara , Alexander Viro , Andrew Morton , Trond Myklebust , David Sterba , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/8] swap: lock i_mutex for swap_writepage direct_IO Message-ID: <20141217080610.GA20335@infradead.org> References: <20141215162705.GA23887@quack.suse.cz> <20141215165615.GA19041@infradead.org> <20141215221100.GA4637@mew> <20141216083543.GA32425@infradead.org> <20141216085624.GA25256@mew> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141216085624.GA25256@mew> User-Agent: Mutt/1.5.23 (2014-03-12) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 16, 2014 at 12:56:24AM -0800, Omar Sandoval wrote: > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -1728,6 +1728,9 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) > } > > if (mapping->a_ops->swap_activate) { > + if (!mapping->a_ops->direct_IO) > + return -EINVAL; > + swap_file->f_flags |= O_DIRECT; > ret = mapping->a_ops->swap_activate(sis, swap_file, span); > if (!ret) { > sis->flags |= SWP_FILE; This needs to hold swap_file->f_lock, but otherwise looks good. > This seems to be more or less equivalent to doing a fcntl(F_SETFL) to > add the O_DIRECT flag to swap_file (which is a struct file *). Swapoff > calls filp_close on swap_file, so I don't see why it's necessary to > clear the flag. filp_lose doesn't nessecarily destroy the file structure, there might be other reference to it, e.g. from dup() or descriptor passing. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/