diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 10bb02c..6dac7ba 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -1295,6 +1295,7 @@
 	 * turn off reservation for this allocation
 	 */
 	if (my_rsv && (free_blocks < windowsz)
+		&& (free_blocks > 0)
 		&& (rsv_is_empty(&my_rsv->rsv_window)))
 		my_rsv = NULL;
 
@@ -1332,7 +1333,7 @@
 		 * free blocks is less than half of the reservation
 		 * window size.
 		 */
-		if (free_blocks <= (windowsz/2))
+		if (my_rsv && (free_blocks <= (windowsz/2)))
 			continue;
 
 		brelse(bitmap_bh);