Re: [PATCH 02/29] nfsd41: encode create_session result into cache

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On Apr 23, 2009, at 7:32 PM, J. Bruce Fields wrote:

On Thu, Apr 23, 2009 at 07:21:05PM -0400, bfields wrote:
On Thu, Apr 23, 2009 at 12:42:41PM -0400, andros@xxxxxxxxxx wrote:
From: Andy Adamson <andros@xxxxxxxxxx>

CREATE_SESSION can be preceeded by a SEQUENCE operation and the
create session single slot cache must be maintained. Encode the results of
a create session call into the cache at the end of processing.

The create session result will also be encoded into the RPC response, and if it is preceeded by a SEQUENCE operation, will also be encoded into the
session slot table cache.

Errors that do not change the create session cache:
A create session NFS4ERR_STALE_CLIENTID error means that a client record (and associated create session slot) could not be found and therefore can't be changed. NFSERR_SEQ_MISORDERED errors do not change the slot cache.

All other errors get cached.

Thanks, this all sounds sensible.  (One simple thing I think I was
confused about: the create_session sequencing is done at a layer above sessions; so in the case of a create_session preceded by a sequence, if
we discover at the point of processing the sequence that this is a
replay, we use the sequence replay cache and never even get to any
create_session processing.  OK!)

Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
---
fs/nfsd/nfs4state.c       |    6 +++++-
fs/nfsd/nfs4xdr.c         |   19 +++++++++++++++++++
include/linux/nfsd/xdr4.h |    2 ++
3 files changed, 26 insertions(+), 1 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 27ad37f..279b47e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1377,7 +1377,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
		if (!same_creds(&unconf->cl_cred, &rqstp->rq_cred) ||
		    (ip_addr != unconf->cl_addr)) {

Could we apply the patch removing these ip_addr checks before any of
these patches? Also I seem to recall expressing some other doubts about the correctness of exchange_id and create_session--I'd like to see those
addressed first, as this builds on those.

			status = nfserr_clid_inuse;
-			goto out;
+			goto out_cache;
		}

		slot = &unconf->cl_slot;
@@ -1424,6 +1424,10 @@ nfsd4_create_session(struct svc_rqst *rqstp,
	cstate->slot = slot;
	/* Ensure a page is used for the cache */
	slot->sl_cache_entry.ce_cachethis = 1;

Is this still needed?

Oh, I see, that's gone in a later patch.  I think that's OK.

I tried various orderings of adding new functionality and removing the old....

-->Andy



--b.


--b.

+out_cache:
+	/* cache solo and embedded create sessions under the state lock */
+	nfsd4_cache_create_session(cr_ses, slot, status);
+
out:
	nfs4_unlock_state();
	dprintk("%s returns %d\n", __func__, ntohl(status));
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index b2f8d74..6b34fac 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3046,6 +3046,25 @@ nfsd4_encode_create_session(struct nfsd4_compoundres *resp, int nfserr,
	return 0;
}

+/*
+ * Encode the create_session result into the create session single DRC + * slot cache. Do this for solo or embedded create session operations.
+ */
+void
+nfsd4_cache_create_session(struct nfsd4_create_session *cr_ses,
+			   struct nfsd4_slot *slot, int nfserr)
+{
+	struct nfsd4_cache_entry *entry = &slot->sl_cache_entry;
+	__be32 *p = (__be32 *)entry->ce_datav.iov_base;
+	struct nfsd4_compoundres tmp = {
+		.p = p,
+		.end = p + XDR_QUADLEN(CS_MAX_ENC_SZ),
+	}, *resp = &tmp;
+
+ entry->ce_status = nfsd4_encode_create_session(resp, nfserr, cr_ses);
+	entry->ce_datav.iov_len = (char *)resp->p - (char *)p;
+}
+
static __be32
nfsd4_encode_destroy_session(struct nfsd4_compoundres *resp, int nfserr,
			     struct nfsd4_destroy_session *destroy_session)
diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
index afd4464..cc50ca0 100644
--- a/include/linux/nfsd/xdr4.h
+++ b/include/linux/nfsd/xdr4.h
@@ -517,6 +517,8 @@ extern __be32 nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
extern void nfsd4_store_cache_entry(struct nfsd4_compoundres *resp);
extern __be32 nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp,
		struct nfsd4_sequence *seq);
+extern void nfsd4_cache_create_session(struct nfsd4_create_session *cr_ses,
+		struct nfsd4_slot *slot, int nfserr);
extern __be32 nfsd4_exchange_id(struct svc_rqst *rqstp,
		struct nfsd4_compound_state *,
struct nfsd4_exchange_id *);
--
1.5.4.3


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