From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-15?Q?Luk=E1=A8_Czerner?= Subject: Re: [PATCH v2 0/2] ext4: Add pollable sysfs entry for block threshold events Date: Wed, 18 Mar 2015 11:12:24 +0100 (CET) Message-ID: References: <1426512329-24299-1-git-send-email-b.michalska@samsung.com> <20150316132843.GA8188@infradead.org> <550945D5.4060805@samsung.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Christoph Hellwig , adilger.kernel@dilger.ca, tytso@mit.edu, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, kyungmin.park@samsung.com To: Beata Michalska Return-path: Received: from mx1.redhat.com ([209.132.183.28]:56009 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755427AbbCRKM4 (ORCPT ); Wed, 18 Mar 2015 06:12:56 -0400 In-Reply-To: <550945D5.4060805@samsung.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, 18 Mar 2015, Beata Michalska wrote: > Date: Wed, 18 Mar 2015 10:31:01 +0100 > From: Beata Michalska > To: Christoph Hellwig > Cc: lczerner@redhat.com, adilger.kernel@dilger.ca, tytso@mit.edu, > linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, > kyungmin.park@samsung.com > Subject: Re: [PATCH v2 0/2] ext4: Add pollable sysfs entry for block threshold > events > > On 03/16/2015 02:28 PM, Christoph Hellwig wrote: > > Between this and the recent tmpfs discussion I really think this > > needs to be done in a generic way. Given that the quota noticiations > > already use netlink general space notifications seem like a very > > sensible extension for them. > > > > First of all, apologies for late response. > > I do agree that having a generic solution is the perfect one > though non-trivial. If I understood You correctly, You would > like to have quota being extended to cover the case in subject; > smth similar to xfs project quota and its pqnoenforce mount > option, as this would require disabling enforcing both: > soft and hard limits ? As Jan already mentioned the problem with quota is that it really is accounting for used space per user, which is not really ideal for this scenario. I have not seen the tmpfs discussions so maybe they have a solution ? Also, implementing noenforce should should be relatively easy. > > > We could also consider going back to already mentioned, > in another thread, the netlink notification interface proposal, > though this still leaves the problem on how to setup the thresholds > (as it covers only the ENOSPC case). As Ted mentioned in one of his replies, filesystem would have to support it at some level. Probably setting a value within a superblock and then check against this value. The netlink notification interface would then serve only as a mean to notify the user. Thanks! -Lukas > > > BR > Beata > >