I have a server which runs on top of hadoop. The problem with hadoop is that there is no way to have persistent file handles. I am currently working on a way to do that - either simulate them or add a support for unique file id to hadoop. If linux client will support volatile file handles then I can stop inventing some workarounds. Tigran. On Sun, Nov 13, 2011 at 4:54 AM, NeilBrown <neilb@xxxxxxx> wrote: > On Sat, 12 Nov 2011 09:49:53 -0500 Christoph Hellwig <hch@xxxxxxxxxxxxx> > wrote: > >> On Fri, Nov 11, 2011 at 07:13:29PM -0500, Trond Myklebust wrote: >> > On Fri, 2011-11-11 at 18:04 -0500, Matthew Treinish wrote: >> > > This patch series implements client side support for volatile file handle >> > > recovery (RFC 3530 section 4.2 and 4.3) with walk back using the dcache. To >> > > test the client you either need a server that supports volatile file handles or >> > > you can hard code the server to output NFS4ERR_FHEXPIRED instead of >> > > NFSERR_STALE. (See the last patch in the series) >> > >> > WHY do we want to support this kind of "feature"? As you said, the RFC >> > doesn't actually help in figuring out how this crap is supposed to work >> > in practice, so why do we even consider starting to give a damn? >> >> *nod*. Pretending we handle it seems fairly dangerous. I'd much prefer >> outright rejecting it. > > Hence the suggested mount option. > > A server might not be able to provide stable file handles, but can ensure > that files don't get renamed - for these filesystems, the name is a > reliable stable handle for the file (it just doesn't fit in the NFSv4 file > handle structure). > > So if you know the filesystem will only return FHEXPIRED for filehandles > belonging to files that cannot be renamed, then it is perfectly reasonable to > repeat the name lookup to re-access the file after the server forgets about > an old filehandle. The mount option is how you communicate this knowledge, > because the RFC doesn't provide a way to communicate it. > > NeilBrown > > > -- 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
