diff -r 116e06273815 sys/src/lib9p/srv.c
--- a/sys/src/lib9p/srv.c	Sun Apr 26 19:55:53 2020 +0200
+++ b/sys/src/lib9p/srv.c	Mon Apr 27 05:31:08 2020 +0200
@@ -214,8 +214,14 @@
 static void
 rauth(Req *r, char *error)
 {
-	if(error && r->afid)
+	if(r->afid == nil)
+		return;
+	if(error){
 		closefid(removefid(r->srv->fpool, r->afid->fid));
+		return;
+	}
+	if(r->afid->omode == -1)
+		r->afid->omode = ORDWR;
 }
 
 static void
@@ -493,6 +499,15 @@
 		respond(r, Eunknownfid);
 		return;
 	}
+	if(r->fid->omode == -1){
+		respond(r, Ebotch);
+		return;
+	}
+	o = r->fid->omode & 3;
+	if(o != OREAD && o != ORDWR && o != OEXEC){
+		respond(r, Ebotch);
+		return;
+	}
 	if((int)r->ifcall.count < 0){
 		respond(r, Ebotch);
 		return;
@@ -502,16 +517,10 @@
 		respond(r, Ebadoffset);
 		return;
 	}
-
 	if(r->ifcall.count > srv->msize - IOHDRSZ)
 		r->ifcall.count = srv->msize - IOHDRSZ;
 	r->rbuf = emalloc9p(r->ifcall.count);
 	r->ofcall.data = r->rbuf;
-	o = r->fid->omode & 3;
-	if(o != OREAD && o != ORDWR && o != OEXEC){
-		respond(r, Ebotch);
-		return;
-	}
 	if((r->fid->qid.type&QTDIR) && r->fid->file){
 		r->ofcall.count = readdirfile(r->fid->rdir, r->rbuf, r->ifcall.count, r->ifcall.offset);
 		respond(r, nil);
@@ -539,6 +548,16 @@
 		respond(r, Eunknownfid);
 		return;
 	}
+	if(r->fid->omode == -1){
+		respond(r, Ebotch);
+		return;
+	}
+	o = r->fid->omode & 3;
+	if(o != OWRITE && o != ORDWR){
+		snprint(e, sizeof e, "write on fid with open mode 0x%ux", r->fid->omode);
+		respond(r, e);
+		return;
+	}
 	if((int)r->ifcall.count < 0){
 		respond(r, Ebotch);
 		return;
@@ -549,12 +568,6 @@
 	}
 	if(r->ifcall.count > srv->msize - IOHDRSZ)
 		r->ifcall.count = srv->msize - IOHDRSZ;
-	o = r->fid->omode & 3;
-	if(o != OWRITE && o != ORDWR){
-		snprint(e, sizeof e, "write on fid with open mode 0x%ux", r->fid->omode);
-		respond(r, e);
-		return;
-	}
 	if(srv->write)
 		srv->write(r);
 	else