diff options
| -rw-r--r-- | fs/nfs/callback_proc.c | 71 |
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 */ |