From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 44C1CC468C6 for ; Thu, 19 Jul 2018 15:52:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0BBBC2084C for ; Thu, 19 Jul 2018 15:52:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0BBBC2084C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732009AbeGSQgd (ORCPT ); Thu, 19 Jul 2018 12:36:33 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33478 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727575AbeGSQgd (ORCPT ); Thu, 19 Jul 2018 12:36:33 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0D7BB81A88D4; Thu, 19 Jul 2018 15:52:46 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-116.rdu2.redhat.com [10.10.120.116]) by smtp.corp.redhat.com (Postfix) with ESMTP id DA06C1C5A6; Thu, 19 Jul 2018 15:52:44 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <20180718154637.31878-1-mszeredi@redhat.com> <18289.1531987758@warthog.procyon.org.uk> To: Miklos Szeredi Cc: dhowells@redhat.com, Miklos Szeredi , Al Viro , overlayfs , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig Subject: Re: [PATCH] vfs: make open_with_fake_path() not contribute to nr_files MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <30899.1532015564.1@warthog.procyon.org.uk> Date: Thu, 19 Jul 2018 16:52:44 +0100 Message-ID: <30900.1532015564@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Thu, 19 Jul 2018 15:52:46 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Thu, 19 Jul 2018 15:52:46 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'dhowells@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Miklos Szeredi wrote: > What the cachefiles use case would be? Cachfiles has to open the backing file so that it can write to it, and it has to do it every time it writes because to leave a bunch of files open contributes to ENFILE/EMFILE. In the near future it's going to have to open the backing file so that it can read from it too as I need to switch to using the io context stuff and get rid of my usage of bmap(). So it would be convenient to be able to keep the open backing file around for longer to avoid constantly needing to open/close it. David