NFSv4: Simplify the struct nfs4_stateid

Replace the union with the common struct stateid4 as defined in both
RFC3530 and RFC5661. This makes it easier to access the sequence id,
which will again make implementing support for parallel OPEN calls
easier.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/callback_xdr.c

@@ -138,10 +138,10 @@ static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
 {
 	__be32 *p;
 
-	p = read_buf(xdr, 16);
+	p = read_buf(xdr, NFS4_STATEID_SIZE);
 	if (unlikely(p == NULL))
 		return htonl(NFS4ERR_RESOURCE);
-	memcpy(stateid->data, p, 16);
+	memcpy(stateid, p, NFS4_STATEID_SIZE);
 	return 0;
 }
 

fs/nfs/nfs4_fs.h

@@ -351,12 +351,12 @@ extern struct svc_version nfs4_callback_version4;
 
 static inline void nfs4_stateid_copy(nfs4_stateid *dst, const nfs4_stateid *src)
 {
-	memcpy(dst->data, src->data, sizeof(dst->data));
+	memcpy(dst, src, sizeof(*dst));
 }
 
 static inline bool nfs4_stateid_match(const nfs4_stateid *dst, const nfs4_stateid *src)
 {
-	return memcmp(dst->data, src->data, sizeof(dst->data)) == 0;
+	return memcmp(dst, src, sizeof(*dst)) == 0;
 }
 
 #else

fs/nfs/nfs4proc.c

@@ -6271,13 +6271,12 @@ static int nfs41_free_stateid(struct nfs_server *server, nfs4_stateid *stateid)
 static bool nfs41_match_stateid(const nfs4_stateid *s1,
 		const nfs4_stateid *s2)
 {
-	if (memcmp(s1->stateid.other, s2->stateid.other,
-		   sizeof(s1->stateid.other)) != 0)
+	if (memcmp(s1->other, s2->other, sizeof(s1->other)) != 0)
 		return false;
 
-	if (s1->stateid.seqid == s2->stateid.seqid)
+	if (s1->seqid == s2->seqid)
 		return true;
-	if (s1->stateid.seqid == 0 || s2->stateid.seqid == 0)
+	if (s1->seqid == 0 || s2->seqid == 0)
 		return true;
 
 	return false;

fs/nfs/nfs4state.c

@@ -1240,8 +1240,8 @@ restart:
 				 * Open state on this file cannot be recovered
 				 * All we can do is revert to using the zero stateid.
 				 */
-				memset(state->stateid.data, 0,
-					sizeof(state->stateid.data));
+				memset(&state->stateid, 0,
+					sizeof(state->stateid));
 				/* Mark the file as being 'closed' */
 				state->state = 0;
 				break;

fs/nfs/nfs4xdr.c

@@ -930,7 +930,7 @@ static void encode_nops(struct compound_hdr *hdr)
 
 static void encode_nfs4_stateid(struct xdr_stream *xdr, const nfs4_stateid *stateid)
 {
-	encode_opaque_fixed(xdr, stateid->data, NFS4_STATEID_SIZE);
+	encode_opaque_fixed(xdr, stateid, NFS4_STATEID_SIZE);
 }
 
 static void encode_nfs4_verifier(struct xdr_stream *xdr, const nfs4_verifier *verf)
@@ -1548,7 +1548,7 @@ static void encode_open_stateid(struct xdr_stream *xdr, const struct nfs_open_co
 	if (ctx->state != NULL) {
 		nfs4_select_rw_stateid(&stateid, ctx->state, l_ctx->lockowner, l_ctx->pid);
 		if (zero_seqid)
-			stateid.stateid.seqid = 0;
+			stateid.seqid = 0;
 		encode_nfs4_stateid(xdr, &stateid);
 	} else
 		encode_nfs4_stateid(xdr, &zero_stateid);
@@ -4237,7 +4237,7 @@ static int decode_opaque_fixed(struct xdr_stream *xdr, void *buf, size_t len)
 
 static int decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
 {
-	return decode_opaque_fixed(xdr, stateid->data, NFS4_STATEID_SIZE);
+	return decode_opaque_fixed(xdr, stateid, NFS4_STATEID_SIZE);
 }
 
 static int decode_close(struct xdr_stream *xdr, struct nfs_closeres *res)

fs/nfs/pnfs.c

@@ -496,12 +496,12 @@ pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, const nfs4_stateid *new,
 {
 	u32 oldseq, newseq;
 
-	oldseq = be32_to_cpu(lo->plh_stateid.stateid.seqid);
-	newseq = be32_to_cpu(new->stateid.seqid);
+	oldseq = be32_to_cpu(lo->plh_stateid.seqid);
+	newseq = be32_to_cpu(new->seqid);
 	if ((int)(newseq - oldseq) > 0) {
 		nfs4_stateid_copy(&lo->plh_stateid, new);
 		if (update_barrier) {
-			u32 new_barrier = be32_to_cpu(new->stateid.seqid);
+			u32 new_barrier = be32_to_cpu(new->seqid);
 
 			if ((int)(new_barrier - lo->plh_barrier))
 				lo->plh_barrier = new_barrier;
@@ -525,7 +525,7 @@ pnfs_layoutgets_blocked(struct pnfs_layout_hdr *lo, nfs4_stateid *stateid,
 			int lget)
 {
 	if ((stateid) &&
-	    (int)(lo->plh_barrier - be32_to_cpu(stateid->stateid.seqid)) >= 0)
+	    (int)(lo->plh_barrier - be32_to_cpu(stateid->seqid)) >= 0)
 		return true;
 	return lo->plh_block_lgets ||
 		test_bit(NFS_LAYOUT_DESTROYED, &lo->plh_flags) ||
@@ -759,7 +759,7 @@ bool pnfs_roc_drain(struct inode *ino, u32 *barrier)
 		}
 	if (!found) {
 		struct pnfs_layout_hdr *lo = nfsi->layout;
-		u32 current_seqid = be32_to_cpu(lo->plh_stateid.stateid.seqid);
+		u32 current_seqid = be32_to_cpu(lo->plh_stateid.seqid);
 
 		/* Since close does not return a layout stateid for use as
 		 * a barrier, we choose the worst-case barrier.

include/linux/nfs4.h

@@ -183,15 +183,12 @@ struct nfs4_acl {
 
 typedef struct { char data[NFS4_VERIFIER_SIZE]; } nfs4_verifier;
 
-struct nfs41_stateid {
+struct nfs_stateid4 {
 	__be32 seqid;
 	char other[NFS4_STATEID_OTHER_SIZE];
 } __attribute__ ((packed));
 
-typedef union {
-	char data[NFS4_STATEID_SIZE];
-	struct nfs41_stateid stateid;
-} nfs4_stateid;
+typedef struct nfs_stateid4 nfs4_stateid;
 
 enum nfs_opnum4 {
 	OP_ACCESS = 3,