BRIN integer overflow

[Oleg Tselebrovskiy]

Greetings, everyone!

While analyzing output of Svace static analyzer [1] I've found a bug
Function bringetbitmap that is used in BRIN's IndexAmRoutine should 
return an
int64 value, but the actual return value is int, since totalpages is int 
and
totalpages * 10 is also int. This could lead to integer overflow

I suggest to change totalpages to be int64 to avoid potential overflow.
Also in all other "amgetbitmap functions" (such as hashgetbitmap, 
gistgetbitmap,
gingetbitmap, blgetbitmap) the return value is of correct int64 type

The proposed patch is attached

[1] - https://svace.pages.ispras.ru/svace-website/en/

Oleg Tselebrovskiy, Postgres Prodiff --git a/src/backend/access/brin/brin.c b/src/backend/access/brin/brin.c
index 1087a9011ea..f72667e484e 100644
--- a/src/backend/access/brin/brin.c
+++ b/src/backend/access/brin/brin.c
@@ -559,7 +559,7 @@ bringetbitmap(IndexScanDesc scan, TIDBitmap *tbm)
 	BrinOpaque *opaque;
 	BlockNumber nblocks;
 	BlockNumber heapBlk;
-	int			totalpages = 0;
+	int64		totalpages = 0;
 	FmgrInfo   *consistentFn;
 	MemoryContext oldcxt;
 	MemoryContext perRangeCxt;