Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-ie0-f182.google.com ([209.85.223.182]:57573 "EHLO mail-ie0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751830Ab3LBQEs convert rfc822-to-8bit (ORCPT ); Mon, 2 Dec 2013 11:04:48 -0500 Received: by mail-ie0-f182.google.com with SMTP id as1so21469791iec.13 for ; Mon, 02 Dec 2013 08:04:48 -0800 (PST) Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.0 \(1812\)) Subject: Re: [PATCH 00/11] [RFC] repair net namespace damage to rpc_pipefs From: Trond Myklebust In-Reply-To: <20131202155722.GE10323@ZenIV.linux.org.uk> Date: Mon, 2 Dec 2013 11:04:46 -0500 Cc: Christoph Hellwig , Linux NFS Mailing List , Devel FS Linux , Torvalds Linus , Eric Biederman Message-Id: <7A4180B4-04D9-4D3C-87AC-820C395599C8@primarydata.com> References: <20131201131441.790963326@bombadil.infradead.org> <20131201181329.GC10323@ZenIV.linux.org.uk> <20131202081233.GA6953@infradead.org> <3C65EB4C-6592-44F8-B08D-E5A9EFD6C8C6@primarydata.com> <20131202155722.GE10323@ZenIV.linux.org.uk> To: Viro Alexander Sender: linux-nfs-owner@vger.kernel.org List-ID: On Dec 2, 2013, at 10:57, Al Viro wrote: > Trond, am I right interpreting you as "that filesystem has non-empty > contents only when there is at least one rpc_client in that netns; > after rpc_client removal there won't be any accesses to data structures > associated with it (due to rpc_close_pipes() and friends, presumably), > so there won't be any need to keep netns alive after that"? > > If so and if rpc_client really can't outlive netns, then yes, having each > of them hold an internal vfsmount reference pinning rpc_pipefs down would > suffice. We do have some ?external? users but in practice their lifetimes are bounded by the lifetimes of the rpc_clients (See my reply to Christoph?s mail). So yes, I believe that it is the case that we need at least one rpc_client in a given nets for the filesystem to be non-empty. Cheers, Trond