nfsd: don't allow setting ctime over v4

Presumably this is left over from earlier drafts of v4, which listed
TIME_METADATA as writeable.  It's read-only in rfc 3530, and shouldn't
be modifiable anyway.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

fs/nfsd/nfs4xdr.c

@@ -376,20 +376,6 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval, struct iattr *ia
 			goto xdr_error;
 		}
 	}
-	if (bmval[1] & FATTR4_WORD1_TIME_METADATA) {
-		/* We require the high 32 bits of 'seconds' to be 0, and we ignore
-		   all 32 bits of 'nseconds'. */
-		READ_BUF(12);
-		len += 12;
-		READ32(dummy32);
-		if (dummy32)
-			return nfserr_inval;
-		READ32(iattr->ia_ctime.tv_sec);
-		READ32(iattr->ia_ctime.tv_nsec);
-		if (iattr->ia_ctime.tv_nsec >= (u32)1000000000)
-			return nfserr_inval;
-		iattr->ia_valid |= ATTR_CTIME;
-	}
 	if (bmval[1] & FATTR4_WORD1_TIME_MODIFY_SET) {
 		READ_BUF(4);
 		len += 4;

include/linux/nfsd/nfsd.h

@@ -329,7 +329,7 @@ extern struct timeval	nfssvc_boot;
 (FATTR4_WORD0_SIZE              | FATTR4_WORD0_ACL                                         )
 #define NFSD_WRITEABLE_ATTRS_WORD1                                                          \
 (FATTR4_WORD1_MODE              | FATTR4_WORD1_OWNER         | FATTR4_WORD1_OWNER_GROUP     \
- | FATTR4_WORD1_TIME_ACCESS_SET | FATTR4_WORD1_TIME_METADATA | FATTR4_WORD1_TIME_MODIFY_SET)
+ | FATTR4_WORD1_TIME_ACCESS_SET | FATTR4_WORD1_TIME_MODIFY_SET)
 
 #endif /* CONFIG_NFSD_V4 */