nfs41: exchange_id operation

Implement the exchange_id operation conforming to
http://tools.ietf.org/html/draft-ietf-nfsv4-minorversion1-26

Unlike NFSv4.0, NFSv4.1 requires machine credentials. RPC_AUTH_GSS machine
credentials will be passed into the kernel at mount time to be available for
the exchange_id operation.

RPC_AUTH_UNIX root mounts can use the UNIX root credential. Store the root
credential in the nfs_client struct.

Without a credential, NFSv4.1 state renewal fails.

[nfs41: establish clientid via exchange id only if cred != NULL]
Signed-off-by: Andy Adamson<andros@umich.edu>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfsd41: move nfstime4 from under CONFIG_NFS_V4_1]
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfs41: do not wait a lease time in exchange id]
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfs41: pass *session in seq_args and seq_res]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
[nfs41: Ignoring impid in decode_exchange_id is missing a READ_BUF]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
[nfs41: fix Xcode_exchange_id's xdr Xcoding pointer type]
[nfs41: get rid of unused struct nfs41_exchange_id_res members]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>

fs/nfs/nfs4proc.c

@@ -48,6 +48,7 @@
 #include <linux/smp_lock.h>
 #include <linux/namei.h>
 #include <linux/mount.h>
+#include <linux/module.h>
 
 #include "nfs4_fs.h"
 #include "delegation.h"
@@ -433,11 +434,13 @@ static int nfs41_setup_sequence(struct nfs4_session *session,
 	spin_unlock(&tbl->slot_tbl_lock);
 
 	slot = tbl->slots + slotid;
+	args->sa_session = session;
 	args->sa_slotid = slotid;
 	args->sa_cache_this = cache_reply;
 
 	dprintk("<-- %s slotid=%d seqid=%d\n", __func__, slotid, slot->seq_nr);
 
+	res->sr_session = session;
 	res->sr_slotid = slotid;
 	res->sr_renewal_time = jiffies;
 	/*
@@ -4128,6 +4131,64 @@ int nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
 }
 
 #ifdef CONFIG_NFS_V4_1
+/*
+ * nfs4_proc_exchange_id()
+ *
+ * Since the clientid has expired, all compounds using sessions
+ * associated with the stale clientid will be returning
+ * NFS4ERR_BADSESSION in the sequence operation, and will therefore
+ * be in some phase of session reset.
+ */
+static int nfs4_proc_exchange_id(struct nfs_client *clp, struct rpc_cred *cred)
+{
+	nfs4_verifier verifier;
+	struct nfs41_exchange_id_args args = {
+		.client = clp,
+		.flags = clp->cl_exchange_flags,
+	};
+	struct nfs41_exchange_id_res res = {
+		.client = clp,
+	};
+	int status;
+	struct rpc_message msg = {
+		.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_EXCHANGE_ID],
+		.rpc_argp = &args,
+		.rpc_resp = &res,
+		.rpc_cred = cred,
+	};
+	__be32 *p;
+
+	dprintk("--> %s\n", __func__);
+	BUG_ON(clp == NULL);
+	p = (u32 *)verifier.data;
+	*p++ = htonl((u32)clp->cl_boot_time.tv_sec);
+	*p = htonl((u32)clp->cl_boot_time.tv_nsec);
+	args.verifier = &verifier;
+
+	while (1) {
+		args.id_len = scnprintf(args.id, sizeof(args.id),
+					"%s/%s %u",
+					clp->cl_ipaddr,
+					rpc_peeraddr2str(clp->cl_rpcclient,
+							 RPC_DISPLAY_ADDR),
+					clp->cl_id_uniquifier);
+
+		status = rpc_call_sync(clp->cl_rpcclient, &msg, 0);
+
+		if (status != NFS4ERR_CLID_INUSE)
+			break;
+
+		if (signalled())
+			break;
+
+		if (++clp->cl_id_uniquifier == 0)
+			break;
+	}
+
+	dprintk("<-- %s status= %d\n", __func__, status);
+	return status;
+}
+
 /* Destroy the slot table */
 static void nfs4_destroy_slot_table(struct nfs4_session *session)
 {

fs/nfs/nfs4xdr.c

@@ -246,6 +246,27 @@ static int nfs4_stat_to_errno(int);
 				(0)
 
 #if defined(CONFIG_NFS_V4_1)
+#define encode_exchange_id_maxsz (op_encode_hdr_maxsz + \
+				encode_verifier_maxsz + \
+				1 /* co_ownerid.len */ + \
+				XDR_QUADLEN(NFS4_EXCHANGE_ID_LEN) + \
+				1 /* flags */ + \
+				1 /* spa_how */ + \
+				0 /* SP4_NONE (for now) */ + \
+				1 /* zero implemetation id array */)
+#define decode_exchange_id_maxsz (op_decode_hdr_maxsz + \
+				2 /* eir_clientid */ + \
+				1 /* eir_sequenceid */ + \
+				1 /* eir_flags */ + \
+				1 /* spr_how */ + \
+				0 /* SP4_NONE (for now) */ + \
+				2 /* eir_server_owner.so_minor_id */ + \
+				/* eir_server_owner.so_major_id<> */ \
+				XDR_QUADLEN(NFS4_OPAQUE_LIMIT) + 1 + \
+				/* eir_server_scope<> */ \
+				XDR_QUADLEN(NFS4_OPAQUE_LIMIT) + 1 + \
+				1 /* eir_server_impl_id array length */ + \
+				0 /* ignored eir_server_impl_id contents */)
 #define encode_sequence_maxsz	0 /* stub */
 #define decode_sequence_maxsz	0 /* stub */
 #else /* CONFIG_NFS_V4_1 */
@@ -594,6 +615,14 @@ static int nfs4_stat_to_errno(int);
 				 decode_putfh_maxsz + \
 				 decode_lookup_maxsz + \
 				 decode_fs_locations_maxsz)
+#if defined(CONFIG_NFS_V4_1)
+#define NFS4_enc_exchange_id_sz \
+				(compound_encode_hdr_maxsz + \
+				 encode_exchange_id_maxsz)
+#define NFS4_dec_exchange_id_sz \
+				(compound_decode_hdr_maxsz + \
+				 decode_exchange_id_maxsz)
+#endif /* CONFIG_NFS_V4_1 */
 
 static const umode_t nfs_type2fmt[] = {
 	[NF4BAD] = 0,
@@ -1455,7 +1484,29 @@ static void encode_delegreturn(struct xdr_stream *xdr, const nfs4_stateid *state
 	hdr->replen += decode_delegreturn_maxsz;
 }
 
+#if defined(CONFIG_NFS_V4_1)
 /* NFSv4.1 operations */
+static void encode_exchange_id(struct xdr_stream *xdr,
+			       struct nfs41_exchange_id_args *args,
+			       struct compound_hdr *hdr)
+{
+	__be32 *p;
+
+	RESERVE_SPACE(4 + sizeof(args->verifier->data));
+	WRITE32(OP_EXCHANGE_ID);
+	WRITEMEM(args->verifier->data, sizeof(args->verifier->data));
+
+	encode_string(xdr, args->id_len, args->id);
+
+	RESERVE_SPACE(12);
+	WRITE32(args->flags);
+	WRITE32(0);	/* zero length state_protect4_a */
+	WRITE32(0);	/* zero length implementation id array */
+	hdr->nops++;
+	hdr->replen += decode_exchange_id_maxsz;
+}
+#endif /* CONFIG_NFS_V4_1 */
+
 static void encode_sequence(struct xdr_stream *xdr,
 			    const struct nfs4_sequence_args *args,
 			    struct compound_hdr *hdr)
@@ -2162,6 +2213,26 @@ static int nfs4_xdr_enc_fs_locations(struct rpc_rqst *req, __be32 *p, struct nfs
 	return 0;
 }
 
+#if defined(CONFIG_NFS_V4_1)
+/*
+ * EXCHANGE_ID request
+ */
+static int nfs4_xdr_enc_exchange_id(struct rpc_rqst *req, uint32_t *p,
+				    struct nfs41_exchange_id_args *args)
+{
+	struct xdr_stream xdr;
+	struct compound_hdr hdr = {
+		.minorversion = args->client->cl_minorversion,
+	};
+
+	xdr_init_encode(&xdr, &req->rq_snd_buf, p);
+	encode_compound_hdr(&xdr, req, &hdr);
+	encode_exchange_id(&xdr, args, &hdr);
+	encode_nops(&hdr);
+	return 0;
+}
+#endif /* CONFIG_NFS_V4_1 */
+
 /*
  * START OF "GENERIC" DECODE ROUTINES.
  *   These may look a little ugly since they are imported from a "generic"
@@ -3877,6 +3948,52 @@ static int decode_delegreturn(struct xdr_stream *xdr)
 	return decode_op_hdr(xdr, OP_DELEGRETURN);
 }
 
+#if defined(CONFIG_NFS_V4_1)
+static int decode_exchange_id(struct xdr_stream *xdr,
+			      struct nfs41_exchange_id_res *res)
+{
+	__be32 *p;
+	uint32_t dummy;
+	int status;
+	struct nfs_client *clp = res->client;
+
+	status = decode_op_hdr(xdr, OP_EXCHANGE_ID);
+	if (status)
+		return status;
+
+	READ_BUF(8);
+	READ64(clp->cl_ex_clid);
+	READ_BUF(12);
+	READ32(clp->cl_seqid);
+	READ32(clp->cl_exchange_flags);
+
+	/* We ask for SP4_NONE */
+	READ32(dummy);
+	if (dummy != SP4_NONE)
+		return -EIO;
+
+	/* Throw away minor_id */
+	READ_BUF(8);
+
+	/* Throw away Major id */
+	READ_BUF(4);
+	READ32(dummy);
+	READ_BUF(dummy);
+
+	/* Throw away server_scope */
+	READ_BUF(4);
+	READ32(dummy);
+	READ_BUF(dummy);
+
+	/* Throw away Implementation id array */
+	READ_BUF(4);
+	READ32(dummy);
+	READ_BUF(dummy);
+
+	return 0;
+}
+#endif /* CONFIG_NFS_V4_1 */
+
 static int decode_sequence(struct xdr_stream *xdr,
 			   struct nfs4_sequence_res *res,
 			   struct rpc_rqst *rqstp)
@@ -4774,6 +4891,25 @@ static int nfs4_xdr_dec_fs_locations(struct rpc_rqst *req, __be32 *p,
 	return status;
 }
 
+#if defined(CONFIG_NFS_V4_1)
+/*
+ * EXCHANGE_ID request
+ */
+static int nfs4_xdr_dec_exchange_id(struct rpc_rqst *rqstp, uint32_t *p,
+				    void *res)
+{
+	struct xdr_stream xdr;
+	struct compound_hdr hdr;
+	int status;
+
+	xdr_init_decode(&xdr, &rqstp->rq_rcv_buf, p);
+	status = decode_compound_hdr(&xdr, &hdr);
+	if (!status)
+		status = decode_exchange_id(&xdr, res);
+	return status;
+}
+#endif /* CONFIG_NFS_V4_1 */
+
 __be32 *nfs4_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus)
 {
 	uint32_t bitmap[2] = {0};
@@ -4943,6 +5079,9 @@ struct rpc_procinfo	nfs4_procedures[] = {
   PROC(GETACL,		enc_getacl,	dec_getacl),
   PROC(SETACL,		enc_setacl,	dec_setacl),
   PROC(FS_LOCATIONS,	enc_fs_locations, dec_fs_locations),
+#if defined(CONFIG_NFS_V4_1)
+  PROC(EXCHANGE_ID,	enc_exchange_id,	dec_exchange_id),
+#endif /* CONFIG_NFS_V4_1 */
 };
 
 struct rpc_version		nfs_version4 = {

include/linux/nfs4.h

@@ -21,6 +21,7 @@
 #define NFS4_FHSIZE		128
 #define NFS4_MAXPATHLEN		PATH_MAX
 #define NFS4_MAXNAMLEN		NAME_MAX
+#define NFS4_OPAQUE_LIMIT	1024
 #define NFS4_MAX_SESSIONID_LEN	16
 
 #define NFS4_ACCESS_READ        0x0001

include/linux/nfs_fs_sb.h

@@ -78,6 +78,12 @@ struct nfs_client {
 #endif /* CONFIG_NFS_V4 */
 
 #ifdef CONFIG_NFS_V4_1
+	/* clientid returned from EXCHANGE_ID, used by session operations */
+	u64			cl_ex_clid;
+	/* The sequence id to use for the next CREATE_SESSION */
+	u32			cl_seqid;
+	/* The flags used for obtaining the clientid during EXCHANGE_ID */
+	u32			cl_exchange_flags;
 	struct nfs4_session	*cl_session; 	/* sharred session */
 #endif /* CONFIG_NFS_V4_1 */
 

include/linux/nfs_xdr.h

@@ -879,6 +879,46 @@ struct nfs4_fs_locations_res {
 
 #endif /* CONFIG_NFS_V4 */
 
+struct nfstime4 {
+	u64	seconds;
+	u32	nseconds;
+};
+
+#ifdef CONFIG_NFS_V4_1
+struct nfs_impl_id4 {
+	u32		domain_len;
+	char		*domain;
+	u32		name_len;
+	char		*name;
+	struct nfstime4	date;
+};
+
+#define NFS4_EXCHANGE_ID_LEN	(48)
+struct nfs41_exchange_id_args {
+	struct nfs_client		*client;
+	nfs4_verifier			*verifier;
+	unsigned int 			id_len;
+	char 				id[NFS4_EXCHANGE_ID_LEN];
+	u32				flags;
+};
+
+struct server_owner {
+	uint64_t			minor_id;
+	uint32_t			major_id_sz;
+	char				major_id[NFS4_OPAQUE_LIMIT];
+};
+
+struct server_scope {
+	uint32_t			server_scope_sz;
+	char 				server_scope[NFS4_OPAQUE_LIMIT];
+};
+
+struct nfs41_exchange_id_res {
+	struct nfs_client		*client;
+	u32				flags;
+};
+#endif /* CONFIG_NFS_V4_1 */
+
 struct nfs_page;
 
 #define NFS_PAGEVEC_SIZE	(8U)

include/linux/nfsd/state.h

@@ -41,7 +41,6 @@
 #include <linux/kref.h>
 #include <linux/sunrpc/clnt.h>
 
-#define NFS4_OPAQUE_LIMIT 1024
 typedef struct {
 	u32             cl_boot;
 	u32             cl_id;