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>

2 files changed, 200 insertions, 0 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index dc0feb5837b1..6f384e290753 100644
--- a/fs/nfs/nfs4proc.c
+++ b/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)
 {
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 5b944cd57218..783c4214dccd 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/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 @@ out:
         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 = {