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authorRicardo Labiaga <Ricardo.Labiaga@netapp.com>2009-04-01 09:23:35 -0400
committerBenny Halevy <bhalevy@panasas.com>2009-06-17 14:11:43 -0700
commit68f3f90133d56e0c38f04f991e662c2b21592b31 (patch)
treee574566b962aa3b90050f5c095d2fb6a354ee386 /fs/nfs
parent963891ac43ecf9974d82f4c178752e11e007cf87 (diff)
nfs41: Backchannel: CB_SEQUENCE validation
Validates the callback's sessionID, the slot number, and the sequence ID. Increments the slot's sequence. Detects replays, but simply prints a debug message (if debugging is enabled since we don't yet implement a duplicate request cache for the backchannel. This should not present a problem, since only idempotent callbacks are currently implemented. Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> [nfs41: Backchannel: Be more obvious about the return value] [nfs41: Backchannel: dprink in host order] Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/callback_proc.c71
1 files changed, 67 insertions, 4 deletions
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 6b342e82ebb..b7da1f54da6 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -105,6 +105,57 @@ out:
#if defined(CONFIG_NFS_V4_1)
/*
+ * Validate the sequenceID sent by the server.
+ * Return success if the sequenceID is one more than what we last saw on
+ * this slot, accounting for wraparound. Increments the slot's sequence.
+ *
+ * We don't yet implement a duplicate request cache, so at this time
+ * we will log replays, and process them as if we had not seen them before,
+ * but we don't bump the sequence in the slot. Not too worried about it,
+ * since we only currently implement idempotent callbacks anyway.
+ *
+ * We have a single slot backchannel at this time, so we don't bother
+ * checking the used_slots bit array on the table. The lower layer guarantees
+ * a single outstanding callback request at a time.
+ */
+static int
+validate_seqid(struct nfs4_slot_table *tbl, u32 slotid, u32 seqid)
+{
+ struct nfs4_slot *slot;
+
+ dprintk("%s enter. slotid %d seqid %d\n",
+ __func__, slotid, seqid);
+
+ if (slotid > NFS41_BC_MAX_CALLBACKS)
+ return htonl(NFS4ERR_BADSLOT);
+
+ slot = tbl->slots + slotid;
+ dprintk("%s slot table seqid: %d\n", __func__, slot->seq_nr);
+
+ /* Normal */
+ if (likely(seqid == slot->seq_nr + 1)) {
+ slot->seq_nr++;
+ return htonl(NFS4_OK);
+ }
+
+ /* Replay */
+ if (seqid == slot->seq_nr) {
+ dprintk("%s seqid %d is a replay - no DRC available\n",
+ __func__, seqid);
+ return htonl(NFS4_OK);
+ }
+
+ /* Wraparound */
+ if (seqid == 1 && (slot->seq_nr + 1) == 0) {
+ slot->seq_nr = 1;
+ return htonl(NFS4_OK);
+ }
+
+ /* Misordered request */
+ return htonl(NFS4ERR_SEQ_MISORDERED);
+}
+
+/*
* Returns a pointer to a held 'struct nfs_client' that matches the server's
* address, major version number, and session ID. It is the caller's
* responsibility to release the returned reference.
@@ -140,18 +191,27 @@ out:
return NULL;
}
-/* FIXME: validate args->cbs_{sequence,slot}id */
/* FIXME: referring calls should be processed */
unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
struct cb_sequenceres *res)
{
- int i;
- unsigned status = 0;
+ struct nfs_client *clp;
+ int i, status;
for (i = 0; i < args->csa_nrclists; i++)
kfree(args->csa_rclists[i].rcl_refcalls);
kfree(args->csa_rclists);
+ status = htonl(NFS4ERR_BADSESSION);
+ clp = find_client_with_session(args->csa_addr, 4, &args->csa_sessionid);
+ if (clp == NULL)
+ goto out;
+
+ status = validate_seqid(&clp->cl_session->bc_slot_table,
+ args->csa_slotid, args->csa_sequenceid);
+ if (status)
+ goto out_putclient;
+
memcpy(&res->csr_sessionid, &args->csa_sessionid,
sizeof(res->csr_sessionid));
res->csr_sequenceid = args->csa_sequenceid;
@@ -159,9 +219,12 @@ unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
+out_putclient:
+ nfs_put_client(clp);
+out:
dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
res->csr_status = status;
- return status;
+ return res->csr_status;
}
#endif /* CONFIG_NFS_V4_1 */