From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Layton Subject: Re: [PATCH 3/3] have pipefs ensure i_ino uniqueness by calling iunique and hashing the inode Date: Fri, 26 Jan 2007 09:42:33 -0500 Message-ID: <45BA1359.7020200@redhat.com> References: <200612291911.kBTJBLvx019107@dantu.rdu.redhat.com> <45B9F939.8070701@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Kirill Korotaev Return-path: Received: from ms-smtp-02.southeast.rr.com ([24.25.9.101]:60670 "EHLO ms-smtp-02.southeast.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030626AbXAZOk4 (ORCPT ); Fri, 26 Jan 2007 09:40:56 -0500 In-Reply-To: <45B9F939.8070701@openvz.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Kirill Korotaev wrote: > Jeff, > > is 100% uniqeness is so much required for pipe inode numbers? > AFAIU, it is not that critical for pipefs (unlike smb, nfs etc.) > > Thanks, > Kirill > There is no in-kernel reason why i_ino uniqueness is important for pipefs. Where it might matter is userspace. The i_ino value is used for: 1) the st_ino value returned in stat calls 2) the dentry name (generated as "[inode_number]") So while it's certainly not "correct" to have multiple inodes with the same number on any filesystem, it is probably more important in some places is others. For pipefs, maybe it isn't, especially given a potential 6% performance impact to fix it. Anyone else have thoughts? -- Jeff