diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 04a5c75..0d42f63 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1808,6 +1808,7 @@
 	ext4_lock_group(ac->ac_sb, group);
 	max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
 			     ac->ac_g_ex.fe_len, &ex);
+	ex.fe_logical = 0xDEADFA11; /* debug value */
 
 	if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
 		ext4_fsblk_t start;
@@ -1936,7 +1937,7 @@
 			 */
 			break;
 		}
-
+		ex.fe_logical = 0xDEADC0DE; /* debug value */
 		ext4_mb_measure_extent(ac, &ex, e4b);
 
 		i += ex.fe_len;
@@ -1977,6 +1978,7 @@
 			max = mb_find_extent(e4b, i, sbi->s_stripe, &ex);
 			if (max >= sbi->s_stripe) {
 				ac->ac_found++;
+				ex.fe_logical = 0xDEADF00D; /* debug value */
 				ac->ac_b_ex = ex;
 				ext4_mb_use_best_found(ac, e4b);
 				break;