bcache: Add a real GC_MARK_RECLAIMABLE

This means the garbage collection code can better check for data and metadata
pointers to the same buckets.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

drivers/md/bcache/bcache.h

@@ -207,9 +207,9 @@ struct bucket {
  */
 
 BITMASK(GC_MARK,	 struct bucket, gc_mark, 0, 2);
-#define GC_MARK_RECLAIMABLE	0
-#define GC_MARK_DIRTY		1
-#define GC_MARK_METADATA	2
+#define GC_MARK_RECLAIMABLE	1
+#define GC_MARK_DIRTY		2
+#define GC_MARK_METADATA	3
 #define GC_SECTORS_USED_SIZE	13
 #define MAX_GC_SECTORS_USED	(~(~0ULL << GC_SECTORS_USED_SIZE))
 BITMASK(GC_SECTORS_USED, struct bucket, gc_mark, 2, GC_SECTORS_USED_SIZE);