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nfs41: Backchannel: CB_SEQUENCE validation

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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>
This commit is contained in:
Ricardo Labiaga 2009-04-01 09:23:35 -04:00 committed by Benny Halevy
parent 963891ac43
commit 68f3f90133
1 changed files with 67 additions and 4 deletions
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71
fs/nfs/callback_proc.c
View file

@ -104,6 +104,57 @@ 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
@ -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 */