Return-Path: Received: from smtp-o-3.desy.de ([131.169.56.156]:39514 "EHLO smtp-o-3.desy.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751452AbdGAJej (ORCPT ); Sat, 1 Jul 2017 05:34:39 -0400 Received: from smtp-map-3.desy.de (smtp-map-3.desy.de [131.169.56.68]) by smtp-o-3.desy.de (DESY-O-3) with ESMTP id 77465280892 for ; Sat, 1 Jul 2017 11:34:37 +0200 (CEST) Date: Sat, 1 Jul 2017 11:34:36 +0200 (CEST) From: "Mkrtchyan, Tigran" To: "J. Bruce Fields" Cc: Trond Myklebust , Christoph Hellwig , Jeff Layton , linux-nfs , schumaker anna Message-ID: <995885135.19496849.1498901676399.JavaMail.zimbra@desy.de> In-Reply-To: <20170630173818.GC14868@fieldses.org> References: <20170629133453.19641-1-hch@lst.de> <20170629154650.GC1651@fieldses.org> <1498842056.6728.1.camel@primarydata.com> <20170630173818.GC14868@fieldses.org> Subject: Re: open by handle support for NFS V2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: ----- Original Message ----- > From: "J. Bruce Fields" > To: "Trond Myklebust" > Cc: "Christoph Hellwig" , "Jeff Layton" , "linux-nfs" , > "schumaker anna" > Sent: Friday, June 30, 2017 7:38:18 PM > Subject: Re: open by handle support for NFS V2 > On Fri, Jun 30, 2017 at 05:00:59PM +0000, Trond Myklebust wrote: >> The main use case for open by filehandle was (and still should be) the >> promise of being able to do the sort of tricks you normally associate >> with object storage on a standard filesystem. >> >> Imagine that you are trying to build an application for indexing and >> searching the data on your storage. You basically want to trawl through >> the filesystem on a regular basis and build up a database of key words >> and other metadata to tell you what is in the files. For that kind of >> application, the namespace is a real PITA to deal with, because files >> get renamed, moved and deleted all the time; so if you can store >> something that is independent of the namespace and that will give you >> access to the file contents, then why wouldn't you do so? Normally, >> applications like that use the inode number, but you can't open a file >> by inode number, and you have the same problems with inode number reuse >> that a NFS server has. >> >> That's the sort of thing I'd think we want to allow through open by >> filehandle, and I see no reason why NFS should be excluded from that >> type of application. > > Thanks, that makes sense. > > We've had open_by_handle support for most filesystems since 2011, is > there evidence of anyone doing this? I am pretty sure that nfs-ganesha is using this in one the backend implementations. Tigran. > > --b. > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html