hash: reduce hash table extent size to 128KB

The 16MB hash table extent size did not serve any useful defragmentation
or compression purpose, and for very small filesystems (under 100GB),
16MB is much larger than necessary.

Signed-off-by: Zygo Blaxell <bees@furryterror.org>

src/bees.h

@@ -56,7 +56,7 @@ const off_t BLOCK_SIZE_MAX_TEMP_FILE = 1024 * 1024 * 1024;
 const off_t BLOCK_SIZE_HASHTAB_BUCKET = BLOCK_SIZE_MMAP;
 
 // Extent size for hash table (since the nocow file attribute does not seem to be working today)
-const off_t BLOCK_SIZE_HASHTAB_EXTENT = 16 * 1024 * 1024;
+const off_t BLOCK_SIZE_HASHTAB_EXTENT = BLOCK_SIZE_MAX_COMPRESSED_EXTENT;
 
 // Bytes per second we want to flush (8GB every two hours)
 const double BEES_FLUSH_RATE = 8.0 * 1024 * 1024 * 1024 / 7200.0;