nfsd: Fix creation time serialization order

In nfsd4_encode_fattr(), TIME_CREATE was being written out after all
other times.  However, they should be written out in an order that
matches the bit flags in bmval1, which in this case are

    #define FATTR4_WORD1_TIME_ACCESS        (1UL << 15)
    #define FATTR4_WORD1_TIME_CREATE        (1UL << 18)
    #define FATTR4_WORD1_TIME_DELTA         (1UL << 19)
    #define FATTR4_WORD1_TIME_METADATA      (1UL << 20)
    #define FATTR4_WORD1_TIME_MODIFY        (1UL << 21)

so TIME_CREATE should come second.

I noticed this on a FreeBSD NFSv4.2 client, which supports creation
times.  On this client, file times were weirdly permuted.  With this
patch applied on the server, times looked normal on the client.

Fixes: e377a3e ("nfsd: Add support for the birth time attribute")
Link: https://unix.stackexchange.com/q/749605/56202
Signed-off-by: Tavian Barnes <tavianator@tavianator.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Author: tavianator

fs/nfsd/nfs4xdr.c

@@ -3370,6 +3370,11 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 		if (status)
 			goto out;
 	}
+	if (bmval1 & FATTR4_WORD1_TIME_CREATE) {
+		status = nfsd4_encode_nfstime4(xdr, &stat.btime);
+		if (status)
+			goto out;
+	}
 	if (bmval1 & FATTR4_WORD1_TIME_DELTA) {
 		p = xdr_reserve_space(xdr, 12);
 		if (!p)
@@ -3386,11 +3391,6 @@ nfsd4_encode_fattr(struct xdr_stream *xdr, struct svc_fh *fhp,
 		if (status)
 			goto out;
 	}
-	if (bmval1 & FATTR4_WORD1_TIME_CREATE) {
-		status = nfsd4_encode_nfstime4(xdr, &stat.btime);
-		if (status)
-			goto out;
-	}
 	if (bmval1 & FATTR4_WORD1_MOUNTED_ON_FILEID) {
 		u64 ino = stat.ino;