4 files changed, 35 insertions, 4 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 99ea196f071f..ee77713ce68b 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -1260,10 +1260,20 @@ error:
 static void nfs4_session_set_rwsize(struct nfs_server *server)
 {
 #ifdef CONFIG_NFS_V4_1
+        struct nfs4_session *sess;
+        u32 server_resp_sz;
+        u32 server_rqst_sz;
+
         if (!nfs4_has_session(server->nfs_client))
                 return;
-        server->rsize = server->nfs_client->cl_session->fc_attrs.max_resp_sz;
-        server->wsize = server->nfs_client->cl_session->fc_attrs.max_rqst_sz;
+        sess = server->nfs_client->cl_session;
+        server_resp_sz = sess->fc_attrs.max_resp_sz - nfs41_maxread_overhead;
+        server_rqst_sz = sess->fc_attrs.max_rqst_sz - nfs41_maxwrite_overhead;
+
+        if (server->rsize > server_resp_sz)
+                server->rsize = server_resp_sz;
+        if (server->wsize > server_rqst_sz)
+                server->wsize = server_rqst_sz;
 #endif /* CONFIG_NFS_V4_1 */
 }
 
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 7466d24893f7..83a9284b83c7 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -191,6 +191,10 @@ extern __be32 *nfs3_decode_dirent(__be32 *, struct nfs_entry *, int);
 #ifdef CONFIG_NFS_V4
 extern __be32 *nfs4_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus);
 #endif
+#ifdef CONFIG_NFS_V4_1
+extern const u32 nfs41_maxread_overhead;
+extern const u32 nfs41_maxwrite_overhead;
+#endif
 
 /* nfs4proc.c */
 extern void nfs4_restart_rpc(struct rpc_task *, const struct nfs_client *,
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index dfd1ea99e2d6..d897b9e34f12 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4862,13 +4862,16 @@ int nfs4_proc_destroy_session(struct nfs4_session *session)
 int nfs4_init_session(struct nfs_server *server)
 {
         struct nfs_client *clp = server->nfs_client;
+        struct nfs4_session *session;
         int ret;
 
         if (!nfs4_has_session(clp))
                 return 0;
 
-        clp->cl_session->fc_attrs.max_rqst_sz = server->wsize;
-        clp->cl_session->fc_attrs.max_resp_sz = server->rsize;
+        session = clp->cl_session;
+        session->fc_attrs.max_rqst_sz = server->wsize + nfs41_maxwrite_overhead;
+        session->fc_attrs.max_resp_sz = server->rsize + nfs41_maxread_overhead;
+
         ret = nfs4_recover_expired_lease(server);
         if (!ret)
                 ret = nfs4_check_client_ready(clp);
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 0b1f3fcdd28a..4ddd04a1113e 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -46,6 +46,7 @@
 #include <linux/proc_fs.h>
 #include <linux/kdev_t.h>
 #include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/msg_prot.h>
 #include <linux/nfs.h>
 #include <linux/nfs4.h>
 #include <linux/nfs_fs.h>
@@ -677,6 +678,19 @@ static int nfs4_stat_to_errno(int);
                                          decode_sequence_maxsz + \
                                          decode_putrootfh_maxsz + \
                                          decode_fsinfo_maxsz)
+
+const u32 nfs41_maxwrite_overhead = ((RPC_MAX_HEADER_WITH_AUTH +
+                                      compound_encode_hdr_maxsz +
+                                      encode_sequence_maxsz +
+                                      encode_putfh_maxsz +
+                                      encode_getattr_maxsz) *
+                                     XDR_UNIT);
+
+const u32 nfs41_maxread_overhead = ((RPC_MAX_HEADER_WITH_AUTH +
+                                     compound_decode_hdr_maxsz +
+                                     decode_sequence_maxsz +
+                                     decode_putfh_maxsz) *
+                                    XDR_UNIT);
 #endif /* CONFIG_NFS_V4_1 */
 
 static const umode_t nfs_type2fmt[] = {