diff --git a/src/afs/VNOPS/afs_vnop_flock.c b/src/afs/VNOPS/afs_vnop_flock.c
index d8b159d82b..8010e738a2 100644
--- a/src/afs/VNOPS/afs_vnop_flock.c
+++ b/src/afs/VNOPS/afs_vnop_flock.c
@@ -434,6 +434,8 @@ HandleFlock(register struct vcache *avc, int acom, struct vrequest *areq,
 			         (tc, code, &avc->f.fid, areq,
 			          AFS_STATS_FS_RPCIDX_SETLOCK, SHARED_LOCK,
 			          NULL));
+			if ((LockType == LockWrite) && (code == VREADONLY))
+			    code = EBADF; /* per POSIX; VREADONLY == EROFS */
 		    } else
 		        /* XXX - Should probably try and log this when we're
 		         * XXX - running with logging enabled. But it's horrid