[PATCH v1 39/61] NFSD: Add a helper to decode state_protect4_a

[Chuck Lever <chuck.lever@xxxxxxxxxx>]

Refactor for clarity.

Also, remove a stale comment. Commit ed94164398c9 ("nfsd: implement
machine credential support for some operations") added support for
SP4_MACH_CRED, so state_protect_a is no longer completely ignored.

Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
 fs/nfsd/nfs4state.c |    2 +-
 fs/nfsd/nfs4xdr.c   |   51 +++++++++++++++++++++++++++++++++------------------
 fs/nfsd/xdr4.h      |    2 +-
 3 files changed, 35 insertions(+), 20 deletions(-)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index d7f27ed6b794..be6dcc4c2ab0 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3066,7 +3066,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 
 	rpc_ntop(sa, addr_str, sizeof(addr_str));
 	dprintk("%s rqstp=%p exid=%p clname.len=%u clname.data=%p "
-		"ip_addr=%s flags %x, spa_how %d\n",
+		"ip_addr=%s flags %x, spa_how %u\n",
 		__func__, rqstp, exid, exid->clname.len, exid->clname.data,
 		addr_str, exid->flags, exid->spa_how);
 
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 4d666e2f8583..d3e238b538d0 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1528,26 +1528,13 @@ static __be32 nfsd4_decode_ssv_sp_parms(struct nfsd4_compoundargs *argp)
 	return nfserr_bad_xdr;
 }
 
-static __be32
-nfsd4_decode_exchange_id(struct nfsd4_compoundargs *argp,
-			 struct nfsd4_exchange_id *exid)
+static __be32 nfsd4_decode_state_protect4_a(struct nfsd4_compoundargs *argp,
+					    struct nfsd4_exchange_id *exid)
 {
-	DECODE_HEAD;
-	int dummy;
-
-	READ_BUF(NFS4_VERIFIER_SIZE);
-	COPYMEM(exid->verifier.data, NFS4_VERIFIER_SIZE);
-
-	status = nfsd4_decode_opaque(argp, &exid->clname);
-	if (status)
-		return nfserr_bad_xdr;
-
-	READ_BUF(4);
-	exid->flags = be32_to_cpup(p++);
+	__be32 status;
 
-	/* Ignore state_protect4_a */
-	READ_BUF(4);
-	exid->spa_how = be32_to_cpup(p++);
+	if (xdr_stream_decode_u32(argp->xdr, &exid->spa_how) < 0)
+		goto xdr_error;
 	switch (exid->spa_how) {
 	case SP4_NONE:
 		break;
@@ -1569,6 +1556,34 @@ nfsd4_decode_exchange_id(struct nfsd4_compoundargs *argp,
 		goto xdr_error;
 	}
 
+	status = nfs_ok;
+out:
+	return status;
+xdr_error:
+	return nfserr_bad_xdr;
+}
+
+static __be32
+nfsd4_decode_exchange_id(struct nfsd4_compoundargs *argp,
+			 struct nfsd4_exchange_id *exid)
+{
+	DECODE_HEAD;
+	int dummy;
+
+	status = nfsd4_decode_verifier4(argp, &exid->verifier);
+	if (status)
+		goto out;
+	status = nfsd4_decode_opaque(argp, &exid->clname);
+	if (status)
+		goto out;
+
+	READ_BUF(4);
+	exid->flags = be32_to_cpup(p++);
+
+	status = nfsd4_decode_state_protect4_a(argp, exid);
+	if (status)
+		goto out;
+
 	READ_BUF(4);    /* nfs_impl_id4 array length */
 	dummy = be32_to_cpup(p++);
 
diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
index 6245004a9993..232529bc1b79 100644
--- a/fs/nfsd/xdr4.h
+++ b/fs/nfsd/xdr4.h
@@ -433,7 +433,7 @@ struct nfsd4_exchange_id {
 	u32		flags;
 	clientid_t	clientid;
 	u32		seqid;
-	int		spa_how;
+	u32		spa_how;
 	u32             spo_must_enforce[3];
 	u32             spo_must_allow[3];
 	struct xdr_netobj nii_domain;