On Sat, Jul 01, 2017 at 11:34:36AM +0200, Mkrtchyan, Tigran wrote: > > > ----- Original Message ----- > > From: "J. Bruce Fields" <bfields@xxxxxxxxxxxx> > > To: "Trond Myklebust" <trondmy@xxxxxxxxxxxxxxx> > > Cc: "Christoph Hellwig" <hch@xxxxxx>, "Jeff Layton" <jlayton@xxxxxxxxxxxxxxx>, "linux-nfs" <linux-nfs@xxxxxxxxxxxxxxx>, > > "schumaker anna" <schumaker.anna@xxxxxxxxx> > > 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. Yes, but I was curious about the kind of application Trond describes. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
