From: "William A. (Andy) Adamson" Subject: Re: [pnfs] [PATCH v2 21/47] nfsd41: nfsd DRC logic Date: Wed, 1 Apr 2009 16:20:02 -0400 Message-ID: <89c397150904011320u2563d18fsbee6636c9a55b5f3@mail.gmail.com> References: <49CDDFC2.4070402@panasas.com> <1238229164-10922-1-git-send-email-bhalevy@panasas.com> <20090331193044.GD20756@fieldses.org> <89c397150904011201j3cc19794x4a017d4e97bcd8f5@mail.gmail.com> <20090401191055.GE8899@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: Benny Halevy , linux-nfs@vger.kernel.org, pnfs@linux-nfs.org To: "J. Bruce Fields" Return-path: Received: from yx-out-2324.google.com ([74.125.44.28]:44147 "EHLO yx-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756434AbZDAUUE (ORCPT ); Wed, 1 Apr 2009 16:20:04 -0400 Received: by yx-out-2324.google.com with SMTP id 31so205963yxl.1 for ; Wed, 01 Apr 2009 13:20:02 -0700 (PDT) In-Reply-To: <20090401191055.GE8899@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Apr 1, 2009 at 3:10 PM, J. Bruce Fields wrote: > On Wed, Apr 01, 2009 at 03:01:53PM -0400, William A. (Andy) Adamson wrote: >> On Tue, Mar 31, 2009 at 3:30 PM, J. Bruce Fields wrote: >> > On Sat, Mar 28, 2009 at 11:32:44AM +0300, Benny Halevy wrote: >> >> From: Andy Adamson >> >> >> >> Replay a request in nfsd4_sequence. >> >> Add a minorversion to struct nfsd4_compound_state. >> >> >> >> Pass the current slot to nfs4svc_encode_compound res via struct >> >> nfsd4_compoundres to set an NFSv4.1 DRC entry. >> >> >> >> Signed-off-by: Andy Adamson >> >> Signed-off-by: Benny Halevy >> >> [nfsd41: use bool inuse for slot state] >> >> Signed-off-by: Benny Halevy >> >> --- >> >> fs/nfsd/nfs4proc.c | 7 +++++++ >> >> fs/nfsd/nfs4state.c | 6 ++++++ >> >> fs/nfsd/nfs4xdr.c | 13 +++++++++++++ >> >> include/linux/nfsd/xdr4.h | 1 + >> >> 4 files changed, 27 insertions(+), 0 deletions(-) >> >> >> >> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c >> >> index e703ac2..bdbeb87 100644 >> >> --- a/fs/nfsd/nfs4proc.c >> >> +++ b/fs/nfsd/nfs4proc.c >> >> @@ -920,6 +920,12 @@ nfsd4_proc_compound(struct svc_rqst *rqstp, >> >> BUG_ON(op->status == nfs_ok); >> >> >> >> encode_op: >> >> + /* Only from SEQUENCE or CREATE_SESSION */ >> >> + if (resp->cstate.status == nfserr_replay_cache) { >> >> + dprintk("%s NFS4.1 replay from cache\n", __func__); >> >> + status = op->status; >> >> + goto out; >> >> + } >> >> if (op->status == nfserr_replay_me) { >> >> op->replay = &cstate->replay_owner->so_replay; >> >> nfsd4_encode_replay(resp, op); >> >> @@ -948,6 +954,7 @@ encode_op: >> >> status = nfserr_jukebox; >> >> } >> >> >> >> + resp->cstate.status = status; >> >> fh_put(&resp->cstate.current_fh); >> >> fh_put(&resp->cstate.save_fh); >> >> BUG_ON(resp->cstate.replay_owner); >> >> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c >> >> index f0ce639..07c869d 100644 >> >> --- a/fs/nfsd/nfs4state.c >> >> +++ b/fs/nfsd/nfs4state.c >> >> @@ -997,6 +997,8 @@ nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp) >> >> } >> >> >> >> resp->rqstp->rq_resused = entry->ce_resused; >> >> + resp->opcnt = entry->ce_opcnt; >> >> + resp->cstate.iovlen = entry->ce_datav.iov_len + entry->ce_rpchdrlen; >> >> status = entry->ce_status; >> >> >> >> return status; >> >> @@ -1217,6 +1219,10 @@ nfsd4_sequence(struct svc_rqst *rqstp, >> >> status = check_slot_seqid(seq->seqid, slot); >> >> if (status == nfserr_replay_cache) { >> >> cstate->slot = slot; >> >> + /* Return the cached reply status and set cstate->status >> >> + * for nfsd4_svc_encode_compoundres processing*/ >> >> + status = nfsd4_replay_cache_entry(resp); >> >> + cstate->status = nfserr_replay_cache; >> >> goto replay_cache; >> >> } >> >> if (status) >> >> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c >> >> index c6b490e..57afb33 100644 >> >> --- a/fs/nfsd/nfs4xdr.c >> >> +++ b/fs/nfsd/nfs4xdr.c >> >> @@ -3059,6 +3059,19 @@ nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compo >> >> iov = &rqstp->rq_res.head[0]; >> >> iov->iov_len = ((char*)resp->p) - (char*)iov->iov_base; >> >> BUG_ON(iov->iov_len > PAGE_SIZE); >> >> +#ifdef CONFIG_NFSD_V4_1 >> >> + if (resp->cstate.slot != NULL) { >> >> + if (resp->cstate.status == nfserr_replay_cache) { >> >> + iov->iov_len = resp->cstate.iovlen; >> >> + } else { >> >> + nfsd4_set_cache_entry(resp); >> >> + dprintk("%s: SET SLOT STATE TO AVAILABLE\n", __func__); >> >> + resp->cstate.slot->sl_inuse = 0; >> >> + } >> >> + if (resp->cstate.slot->sl_session) >> > >> > There's no way that sl_session could ever be NULL, so this check is >> > unneeded. >> >> There should have been a comment. >> CREATE_SESSION sets cstate->slot using the nfs4_client->cl_slot, a >> single slot which it uses for the CREATE_SESSION replay cache. It does >> not have a session. > > Hm. In that case, there's no reference count on the client that holds > the cl_slot structure, so is there anything preventing the cl_slot from > being freed out from under us by a concurrent expire_client()? That is true, we don't bump the client cl_count.... > > If that's correct: I'm not sure how to solve that problem with a minimum > of special-casing. Hmm. I see what you mean. We would like to take a reference to the nfs4_client in nfsd4_create_session and drop it in nfs4svc_encode_compoundres if the session pointer is NULL. if (resp->cstate->session) nfsd4_put_session(resp>cstate->session) else nfsd4_put_client(???) but - we currently have no nfs4_client back pointer (except in the session which is null.......) -->Andy > > --b. > >> >> >> > >> > While we're at it: let's just eliminate the sl_session pointer from the >> > slot. I think all that would be needed would be a pointer to the >> > session from the cstate, in addition to the pointer to the slot. >> >> OK. >> >> > >> > --b. >> > >> >> + nfsd4_put_session(resp->cstate.slot->sl_session); >> >> + } >> >> +#endif /* CONFIG_NFSD_V4_1 */ >> >> return 1; >> >> } >> >> >> >> diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h >> >> index cde8947..5c0d376 100644 >> >> --- a/include/linux/nfsd/xdr4.h >> >> +++ b/include/linux/nfsd/xdr4.h >> >> @@ -51,6 +51,7 @@ struct nfsd4_compound_state { >> >> /* For sessions DRC */ >> >> struct nfsd4_slot *slot; >> >> __be32 *statp; >> >> + size_t iovlen; >> >> u32 status; >> >> }; >> >> >> >> -- >> >> 1.6.2.1 >> >> >> > _______________________________________________ >> > pNFS mailing list >> > pNFS@linux-nfs.org >> > http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs >> > >