All files:

Each piece must have at least one byte for their block bit array,
  or they will collide causing great confusion in btpd. The calculation
  was done wrong so this could happen for small torrents (blocks / piece < 8).

policy_subr.c:
  * Add test for correctness.
  * Add missing call to cm_on_piece_full in cm_new_piece.

btpd/policy_subr.c

@@ -48,7 +48,7 @@ piece_alloc(struct torrent *tp, uint32_t index)
     pc->down_field = (uint8_t *)(pc + 1);
     pc->have_field =
 	tp->block_field +
-	(size_t)ceil(index * tp->meta.piece_length / (double)(1 << 17));
+	index * (size_t)ceil(tp->meta.piece_length / (double)(1 << 17));
     pc->nblocks = nblocks;
     pc->index = index;
 
@@ -254,6 +254,24 @@ cm_choose_rarest(struct peer *p, uint32_t *res)
     return 0;
 }
 
+/*
+ * Called from either cm_piece_assign_requests or cm_new_piece, 
+ * when a pice becomes full. The wanted level of the peers
+ * that has this piece will be decreased. This function is
+ * the only one that may trigger end game.
+ */
+static void
+cm_on_piece_full(struct piece *pc)
+{
+    struct peer *p;
+    BTPDQ_FOREACH(p, &pc->tp->peers, cm_entry) {
+	if (peer_has(p, pc->index))
+	    peer_unwant(p, pc->index);
+    }
+    if (cm_should_enter_endgame(pc->tp))
+	cm_enter_endgame(pc->tp);
+}
+
 /*
  * Allocate the piece indicated by the index for download.
  * There's a small possibility that a piece is fully downloaded
@@ -269,6 +287,7 @@ cm_new_piece(struct torrent *tp, uint32_t index)
     btpd_log(BTPD_L_POL, "Started on piece %u.\n", index);
     struct piece *pc = piece_alloc(tp, index);
     if (pc->ngot == pc->nblocks) {
+	cm_on_piece_full(pc);
 	cm_on_piece(pc);
 	if (cm_should_enter_endgame(tp))
 	    cm_enter_endgame(tp);
@@ -277,25 +296,6 @@ cm_new_piece(struct torrent *tp, uint32_t index)
 	return pc;
 }
 
-/*
- * Called from either cm_piece_assign_requests or cm_new_piece, 
- * when a pice becomes full. The wanted level of the peers
- * that has this piece will be decreased. This function is
- * the only one that may trigger end game.
- */
-static void
-cm_on_piece_full(struct piece *pc)
-{
-    struct peer *p;
-    BTPDQ_FOREACH(p, &pc->tp->peers, cm_entry) {
-	if (peer_has(p, pc->index))
-	    peer_unwant(p, pc->index);
-    }
-    if (cm_should_enter_endgame(pc->tp))
-	cm_enter_endgame(pc->tp);
-}
-
-
 /*
  * Called when a previously full piece loses a peer.
  * This is needed because we have decreased the wanted
@@ -360,7 +360,7 @@ cm_piece_assign_requests(struct piece *pc, struct peer *p)
 unsigned
 cm_assign_requests(struct peer *p)
 {
-    assert(!p->tp->endgame);
+    assert(!p->tp->endgame && !peer_laden(p));
     struct piece *pc;
     struct torrent *tp = p->tp;
     unsigned count = 0;

btpd/torrent.c

@@ -94,7 +94,7 @@ torrent_load2(const char *file, struct metainfo *mi)
 
     memsiz =
 	ceil(mi->npieces / 8.0) +
-	ceil(mi->npieces * mi->piece_length / (double)(1 << 17));
+	mi->npieces * ceil(mi->piece_length / (double)(1 << 17));
 
     if (sb.st_size != memsiz) {
 	btpd_log(BTPD_L_ERROR, "File has wrong size: %s.i.\n", file);

cli/btcli.c

@@ -138,9 +138,8 @@ gen_ifile(char *path)
     if ((errno = vopen(&fd, O_WRONLY|O_CREAT, "%s.i", path)) != 0)
 	err(1, "opening %s.i", path);
 
-    if (ftruncate(fd,
-            field_len +
-	    (off_t)ceil(mi->npieces * mi->piece_length / (double)(1<<17))) < 0)
+    if (ftruncate(fd, field_len + mi->npieces *
+	    (off_t)ceil(mi->piece_length / (double)(1 << 17))) < 0)
 	err(1, "ftruncate: %s", path);
 
     if (write(fd, cb.piece_field, field_len) != field_len)