[gegl] buffer: in swap backend, mark returned queued tiles as stored

[Ell <ell src gnome org>]

commit b1b2cc8553a41eaf9bb63a5c57ca6e9b5338f8d3
Author: Ell <ell_se yahoo com>
Date:   Tue Jul 3 09:18:11 2018 -0400

    buffer: in swap backend, mark returned queued tiles as stored
    
    In GeglTileBackendSwap, when returning a tile that's still queued
    for writing in response to a GET command (in which case the
    returned tile is a duplicate of the queued tile), mark the tile as
    stored before returning it.  Duplicate tiles are initially
    considered dirty.

 gegl/buffer/gegl-tile-backend-swap.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gegl/buffer/gegl-tile-backend-swap.c b/gegl/buffer/gegl-tile-backend-swap.c
index 779ffc9b5..08c88436f 100644
--- a/gegl/buffer/gegl-tile-backend-swap.c
+++ b/gegl/buffer/gegl-tile-backend-swap.c
@@ -484,8 +484,11 @@ gegl_tile_backend_swap_entry_read (GeglTileBackendSwap *self,
       if (queued_op)
         {
           tile = gegl_tile_dup (queued_op->tile);
+
           g_mutex_unlock (&queue_mutex);
 
+          gegl_tile_mark_as_stored (tile);
+
           GEGL_NOTE(GEGL_DEBUG_TILE_BACKEND, "read entry %i, %i, %i from queue", entry->x, entry->y, 
entry->z);
 
           return tile;