nfs4.1: add BIND_CONN_TO_SESSION operation

This patch adds the BIND_CONN_TO_SESSION operation which is needed for
upcoming SP4_MACH_CRED work and useful for recovering from broken connections
without destroying the session.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 150 insertions, 0 deletions

diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index e6da02124c4e..2c7f1cf85b8f 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -211,6 +211,7 @@ struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,
 extern int nfs4_proc_setclientid(struct nfs_client *, u32, unsigned short, struct rpc_cred *, struct nfs4_setclientid_res *);
 extern int nfs4_proc_setclientid_confirm(struct nfs_client *, struct nfs4_setclientid_res *arg, struct rpc_cred *);
 extern int nfs4_proc_get_rootfh(struct nfs_server *, struct nfs_fh *, struct nfs_fsinfo *);
+extern int nfs4_proc_bind_conn_to_session(struct nfs_client *);
 extern int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred);
 extern int nfs4_init_clientid(struct nfs_client *, struct rpc_cred *);
 extern int nfs41_init_clientid(struct nfs_client *, struct rpc_cred *);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e725736ff288..e8988c000e7f 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5100,6 +5100,60 @@ nfs41_same_server_scope(struct nfs41_server_scope *a,
 }
 
 /*
+ * nfs4_proc_bind_conn_to_session()
+ *
+ * The 4.1 client currently uses the same TCP connection for the
+ * fore and backchannel.
+ */
+int nfs4_proc_bind_conn_to_session(struct nfs_client *clp)
+{
+        int status;
+        struct nfs41_bind_conn_to_session_res res;
+        struct rpc_message msg = {
+                .rpc_proc =
+                        &nfs4_procedures[NFSPROC4_CLNT_BIND_CONN_TO_SESSION],
+                .rpc_argp = clp,
+                .rpc_resp = &res,
+        };
+
+        dprintk("--> %s\n", __func__);
+        BUG_ON(clp == NULL);
+
+        res.session = kzalloc(sizeof(struct nfs4_session), GFP_NOFS);
+        if (unlikely(res.session == NULL)) {
+                status = -ENOMEM;
+                goto out;
+        }
+
+        status = rpc_call_sync(clp->cl_rpcclient, &msg, RPC_TASK_TIMEOUT);
+        if (status == 0) {
+                if (memcmp(res.session->sess_id.data,
+                    clp->cl_session->sess_id.data, NFS4_MAX_SESSIONID_LEN)) {
+                        dprintk("NFS: %s: Session ID mismatch\n", __func__);
+                        status = -EIO;
+                        goto out_session;
+                }
+                if (res.dir != NFS4_CDFS4_BOTH) {
+                        dprintk("NFS: %s: Unexpected direction from server\n",
+                                __func__);
+                        status = -EIO;
+                        goto out_session;
+                }
+                if (res.use_conn_in_rdma_mode) {
+                        dprintk("NFS: %s: Server returned RDMA mode = true\n",
+                                __func__);
+                        status = -EIO;
+                        goto out_session;
+                }
+        }
+out_session:
+        kfree(res.session);
+out:
+        dprintk("<-- %s status= %d\n", __func__, status);
+        return status;
+}
+
+/*
  * nfs4_proc_exchange_id()
  *
  * Since the clientid has expired, all compounds using sessions
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index edb8ac7fce0e..a6b95b766220 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -326,6 +326,16 @@ static int nfs4_stat_to_errno(int);
                                      1 /* csr_flags */ + \
                                      decode_channel_attrs_maxsz + \
                                      decode_channel_attrs_maxsz)
+#define encode_bind_conn_to_session_maxsz  (op_encode_hdr_maxsz + \
+                                     /* bctsa_sessid */ \
+                                     XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + \
+                                     1 /* bctsa_dir */ + \
+                                     1 /* bctsa_use_conn_in_rdma_mode */)
+#define decode_bind_conn_to_session_maxsz  (op_decode_hdr_maxsz +       \
+                                     /* bctsr_sessid */ \
+                                     XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + \
+                                     1 /* bctsr_dir */ + \
+                                     1 /* bctsr_use_conn_in_rdma_mode */)
 #define encode_destroy_session_maxsz    (op_encode_hdr_maxsz + 4)
 #define decode_destroy_session_maxsz    (op_decode_hdr_maxsz)
 #define encode_sequence_maxsz   (op_encode_hdr_maxsz + \
@@ -719,6 +729,12 @@ static int nfs4_stat_to_errno(int);
                                 decode_putfh_maxsz + \
                                 decode_secinfo_maxsz)
 #if defined(CONFIG_NFS_V4_1)
+#define NFS4_enc_bind_conn_to_session_sz \
+                                (compound_encode_hdr_maxsz + \
+                                 encode_bind_conn_to_session_maxsz)
+#define NFS4_dec_bind_conn_to_session_sz \
+                                (compound_decode_hdr_maxsz + \
+                                 decode_bind_conn_to_session_maxsz)
 #define NFS4_enc_exchange_id_sz \
                                 (compound_encode_hdr_maxsz + \
                                  encode_exchange_id_maxsz)
@@ -1669,6 +1685,20 @@ static void encode_secinfo(struct xdr_stream *xdr, const struct qstr *name, stru
 
 #if defined(CONFIG_NFS_V4_1)
 /* NFSv4.1 operations */
+static void encode_bind_conn_to_session(struct xdr_stream *xdr,
+                                   struct nfs4_session *session,
+                                   struct compound_hdr *hdr)
+{
+        __be32 *p;
+
+        encode_op_hdr(xdr, OP_BIND_CONN_TO_SESSION,
+                decode_bind_conn_to_session_maxsz, hdr);
+        encode_opaque_fixed(xdr, session->sess_id.data, NFS4_MAX_SESSIONID_LEN);
+        p = xdr_reserve_space(xdr, 8);
+        *p++ = cpu_to_be32(NFS4_CDFC4_BACK_OR_BOTH);
+        *p = 0; /* use_conn_in_rdma_mode = False */
+}
+
 static void encode_exchange_id(struct xdr_stream *xdr,
                                struct nfs41_exchange_id_args *args,
                                struct compound_hdr *hdr)
@@ -2630,6 +2660,22 @@ static void nfs4_xdr_enc_secinfo(struct rpc_rqst *req,
 
 #if defined(CONFIG_NFS_V4_1)
 /*
+ * BIND_CONN_TO_SESSION request
+ */
+static void nfs4_xdr_enc_bind_conn_to_session(struct rpc_rqst *req,
+                                struct xdr_stream *xdr,
+                                struct nfs_client *clp)
+{
+        struct compound_hdr hdr = {
+                .minorversion = clp->cl_mvops->minor_version,
+        };
+
+        encode_compound_hdr(xdr, req, &hdr);
+        encode_bind_conn_to_session(xdr, clp->cl_session, &hdr);
+        encode_nops(&hdr);
+}
+
+/*
  * EXCHANGE_ID request
  */
 static void nfs4_xdr_enc_exchange_id(struct rpc_rqst *req,
@@ -5366,6 +5412,37 @@ static int decode_sessionid(struct xdr_stream *xdr, struct nfs4_sessionid *sid)
         return decode_opaque_fixed(xdr, sid->data, NFS4_MAX_SESSIONID_LEN);
 }
 
+static int decode_bind_conn_to_session(struct xdr_stream *xdr,
+                                struct nfs41_bind_conn_to_session_res *res)
+{
+        __be32 *p;
+        int status;
+
+        status = decode_op_hdr(xdr, OP_BIND_CONN_TO_SESSION);
+        if (!status)
+                status = decode_sessionid(xdr, &res->session->sess_id);
+        if (unlikely(status))
+                return status;
+
+        /* dir flags, rdma mode bool */
+        p = xdr_inline_decode(xdr, 8);
+        if (unlikely(!p))
+                goto out_overflow;
+
+        res->dir = be32_to_cpup(p++);
+        if (res->dir == 0 || res->dir > NFS4_CDFS4_BOTH)
+                return -EIO;
+        if (be32_to_cpup(p) == 0)
+                res->use_conn_in_rdma_mode = false;
+        else
+                res->use_conn_in_rdma_mode = true;
+
+        return 0;
+out_overflow:
+        print_overflow_msg(__func__, xdr);
+        return -EIO;
+}
+
 static int decode_create_session(struct xdr_stream *xdr,
                                  struct nfs41_create_session_res *res)
 {
@@ -6648,6 +6725,22 @@ out:
 
 #if defined(CONFIG_NFS_V4_1)
 /*
+ * Decode BIND_CONN_TO_SESSION response
+ */
+static int nfs4_xdr_dec_bind_conn_to_session(struct rpc_rqst *rqstp,
+                                        struct xdr_stream *xdr,
+                                        void *res)
+{
+        struct compound_hdr hdr;
+        int status;
+
+        status = decode_compound_hdr(xdr, &hdr);
+        if (!status)
+                status = decode_bind_conn_to_session(xdr, res);
+        return status;
+}
+
+/*
  * Decode EXCHANGE_ID response
  */
 static int nfs4_xdr_dec_exchange_id(struct rpc_rqst *rqstp,
@@ -7128,6 +7221,8 @@ struct rpc_procinfo	nfs4_procedures[] = {
         PROC(RELEASE_LOCKOWNER, enc_release_lockowner,  dec_release_lockowner),
         PROC(SECINFO,           enc_secinfo,            dec_secinfo),
 #if defined(CONFIG_NFS_V4_1)
+        PROC(BIND_CONN_TO_SESSION,
+                        enc_bind_conn_to_session, dec_bind_conn_to_session),
         PROC(EXCHANGE_ID,       enc_exchange_id,        dec_exchange_id),
         PROC(CREATE_SESSION,    enc_create_session,     dec_create_session),
         PROC(DESTROY_SESSION,   enc_destroy_session,    dec_destroy_session),