nfsd: Decode and send 64bit time values

The seconds field of an nfstime4 structure is 64bit, but we are assuming
that the first 32bits are zero-filled.  So if the client tries to set
atime to a value before the epoch (touch -t 196001010101), then the
server will save the wrong value on disk.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4xdr.c

@@ -344,10 +344,7 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
 			   all 32 bits of 'nseconds'. */
 			READ_BUF(12);
 			len += 12;
-			READ32(dummy32);
-			if (dummy32)
-				return nfserr_inval;
-			READ32(iattr->ia_atime.tv_sec);
+			READ64(iattr->ia_atime.tv_sec);
 			READ32(iattr->ia_atime.tv_nsec);
 			if (iattr->ia_atime.tv_nsec >= (u32)1000000000)
 				return nfserr_inval;
@@ -370,10 +367,7 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
 			   all 32 bits of 'nseconds'. */
 			READ_BUF(12);
 			len += 12;
-			READ32(dummy32);
-			if (dummy32)
-				return nfserr_inval;
-			READ32(iattr->ia_mtime.tv_sec);
+			READ64(iattr->ia_mtime.tv_sec);
 			READ32(iattr->ia_mtime.tv_nsec);
 			if (iattr->ia_mtime.tv_nsec >= (u32)1000000000)
 				return nfserr_inval;
@@ -2372,8 +2366,7 @@ out_acl:
 	if (bmval1 & FATTR4_WORD1_TIME_ACCESS) {
 		if ((buflen -= 12) < 0)
 			goto out_resource;
-		WRITE32(0);
-		WRITE32(stat.atime.tv_sec);
+		WRITE64((s64)stat.atime.tv_sec);
 		WRITE32(stat.atime.tv_nsec);
 	}
 	if (bmval1 & FATTR4_WORD1_TIME_DELTA) {
@@ -2386,15 +2379,13 @@ out_acl:
 	if (bmval1 & FATTR4_WORD1_TIME_METADATA) {
 		if ((buflen -= 12) < 0)
 			goto out_resource;
-		WRITE32(0);
-		WRITE32(stat.ctime.tv_sec);
+		WRITE64((s64)stat.ctime.tv_sec);
 		WRITE32(stat.ctime.tv_nsec);
 	}
 	if (bmval1 & FATTR4_WORD1_TIME_MODIFY) {
 		if ((buflen -= 12) < 0)
 			goto out_resource;
-		WRITE32(0);
-		WRITE32(stat.mtime.tv_sec);
+		WRITE64((s64)stat.mtime.tv_sec);
 		WRITE32(stat.mtime.tv_nsec);
 	}
 	if (bmval1 & FATTR4_WORD1_MOUNTED_ON_FILEID) {