1 files changed, 17 insertions, 12 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index c484a2b6cd10..0462eeddfff9 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -2408,7 +2408,8 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
         default:                                /* checked by xdr code */
                 WARN_ON_ONCE(1);
         case SP4_SSV:
-                return nfserr_encr_alg_unsupp;
+                status = nfserr_encr_alg_unsupp;
+                goto out_nolock;
         }
 
         /* Cases below refer to rfc 5661 section 18.35.4: */
@@ -2586,21 +2587,26 @@ static __be32 check_forechannel_attrs(struct nfsd4_channel_attrs *ca, struct nfs
         return nfs_ok;
 }
 
+/*
+ * Server's NFSv4.1 backchannel support is AUTH_SYS-only for now.
+ * These are based on similar macros in linux/sunrpc/msg_prot.h .
+ */
+#define RPC_MAX_HEADER_WITH_AUTH_SYS \
+        (RPC_CALLHDRSIZE + 2 * (2 + UNX_CALLSLACK))
+
+#define RPC_MAX_REPHEADER_WITH_AUTH_SYS \
+        (RPC_REPHDRSIZE + (2 + NUL_REPLYSLACK))
+
 #define NFSD_CB_MAX_REQ_SZ      ((NFS4_enc_cb_recall_sz + \
-                                 RPC_MAX_HEADER_WITH_AUTH) * sizeof(__be32))
+                                 RPC_MAX_HEADER_WITH_AUTH_SYS) * sizeof(__be32))
 #define NFSD_CB_MAX_RESP_SZ     ((NFS4_dec_cb_recall_sz + \
-                                 RPC_MAX_REPHEADER_WITH_AUTH) * sizeof(__be32))
+                                 RPC_MAX_REPHEADER_WITH_AUTH_SYS) * \
+                                 sizeof(__be32))
 
 static __be32 check_backchannel_attrs(struct nfsd4_channel_attrs *ca)
 {
         ca->headerpadsz = 0;
 
-        /*
-         * These RPC_MAX_HEADER macros are overkill, especially since we
-         * don't even do gss on the backchannel yet.  But this is still
-         * less than 1k.  Tighten up this estimate in the unlikely event
-         * it turns out to be a problem for some client:
-         */
         if (ca->maxreq_sz < NFSD_CB_MAX_REQ_SZ)
                 return nfserr_toosmall;
         if (ca->maxresp_sz < NFSD_CB_MAX_RESP_SZ)
@@ -2710,10 +2716,9 @@ nfsd4_create_session(struct svc_rqst *rqstp,
                 goto out_free_conn;
         }
         status = nfs_ok;
-        /*
-         * We do not support RDMA or persistent sessions
-         */
+        /* Persistent sessions are not supported */
         cr_ses->flags &= ~SESSION4_PERSIST;
+        /* Upshifting from TCP to RDMA is not supported */
         cr_ses->flags &= ~SESSION4_RDMA;
 
         init_session(rqstp, new, conf, cr_ses);