diff --git a/kmod/src/data.c b/kmod/src/data.c
index 6b581a3b..48aae57a 100644
--- a/kmod/src/data.c
+++ b/kmod/src/data.c
@@ -458,11 +458,9 @@ static int alloc_block(struct super_block *sb, struct inode *inode,
 		/*
 		 * Preallocation within aligned regions tries to
 		 * allocate an extent to fill the hole in the region
-		 * that contains iblock.  We search for a next extent
-		 * from the start of the region.  If it's at the start
-		 * we might have to search again to find an existing
-		 * extent at the end of the region.  (This next could be
-		 * given to us by the caller).
+		 * that contains iblock.  We'd have to add a bit of plumbing
+		 * to find previous extents so we only search for a next
+		 * extent from the front of the region and from iblock.
 		 */
 		div64_u64_rem(iblock, opts.data_prealloc_blocks, &rem);
 		start = iblock - rem;
@@ -473,15 +471,15 @@ static int alloc_block(struct super_block *sb, struct inode *inode,
 
 		/* trim count if there's an extent in the region before iblock */
 		if (found.len && found.start < iblock) {
-			count -= (found.start + found.len) - start;
-			start = found.start + found.len;
+			count -= iblock - start;
+			start = iblock;
 			/* see if there's also an extent after iblock */
 			ret = scoutfs_ext_next(sb, &data_ext_ops, &args, iblock, 1, &found);
 			if (ret < 0 && ret != -ENOENT)
 				goto out;
 		}
 
-		/* trim count by a next extent in the region */
+		/* trim count by next extent after iblock */
 		if (found.len && found.start > start && found.start < start + count)
 			count = (found.start - start);
 	}
diff --git a/tests/golden/data-prealloc b/tests/golden/data-prealloc
index f6ac8d65..ddea23cf 100644
--- a/tests/golden/data-prealloc
+++ b/tests/golden/data-prealloc
@@ -122,7 +122,6 @@ wrote blk 39
 25.. 1: 
 26.. 6: unwritten
 32.. 1: 
-33.. 6: unwritten
 39.. 1: 
 40.. 1: 
 55.. 1: 
@@ -143,10 +142,8 @@ wrote blk 44
 25.. 1: 
 26.. 6: unwritten
 32.. 1: 
-33.. 6: unwritten
 39.. 1: 
 40.. 1: 
-41.. 3: unwritten
 44.. 1: 
 45.. 3: unwritten
 55.. 1: 
@@ -167,10 +164,8 @@ wrote blk 48
 25.. 1: 
 26.. 6: unwritten
 32.. 1: 
-33.. 6: unwritten
 39.. 1: 
 40.. 1: 
-41.. 3: unwritten
 44.. 1: 
 45.. 3: unwritten
 48.. 1: 
@@ -193,10 +188,8 @@ wrote blk 62
 25.. 1: 
 26.. 6: unwritten
 32.. 1: 
-33.. 6: unwritten
 39.. 1: 
 40.. 1: 
-41.. 3: unwritten
 44.. 1: 
 45.. 3: unwritten
 48.. 1: 
@@ -221,10 +214,8 @@ wrote blk 67
 25.. 1: 
 26.. 6: unwritten
 32.. 1: 
-33.. 6: unwritten
 39.. 1: 
 40.. 1: 
-41.. 3: unwritten
 44.. 1: 
 45.. 3: unwritten
 48.. 1: 
@@ -252,10 +243,8 @@ wrote blk 73
 25.. 1: 
 26.. 6: unwritten
 32.. 1: 
-33.. 6: unwritten
 39.. 1: 
 40.. 1: 
-41.. 3: unwritten
 44.. 1: 
 45.. 3: unwritten
 48.. 1: 
@@ -285,10 +274,8 @@ wrote blk 86
 25.. 1: 
 26.. 6: unwritten
 32.. 1: 
-33.. 6: unwritten
 39.. 1: 
 40.. 1: 
-41.. 3: unwritten
 44.. 1: 
 45.. 3: unwritten
 48.. 1: 
@@ -304,7 +291,6 @@ wrote blk 86
 73.. 1: 
 74.. 5: unwritten
 79.. 2: 
-81.. 5: unwritten
 86.. 1: 
 87.. 2: 
 95.. 1: eof
@@ -320,10 +306,8 @@ wrote blk 92
 25.. 1: 
 26.. 6: unwritten
 32.. 1: 
-33.. 6: unwritten
 39.. 1: 
 40.. 1: 
-41.. 3: unwritten
 44.. 1: 
 45.. 3: unwritten
 48.. 1: 
@@ -339,10 +323,8 @@ wrote blk 92
 73.. 1: 
 74.. 5: unwritten
 79.. 2: 
-81.. 5: unwritten
 86.. 1: 
 87.. 2: 
-89.. 3: unwritten
 92.. 1: 
 93.. 2: unwritten
 95.. 1: eof
diff --git a/tests/tests/data-prealloc.sh b/tests/tests/data-prealloc.sh
index 09f42637..fdc09f8e 100644
--- a/tests/tests/data-prealloc.sh
+++ b/tests/tests/data-prealloc.sh
@@ -168,7 +168,8 @@ print_extents_found $prefix
 # the start, and one at the end.
 #
 # Let's keep this last because it creates a ton of output to read
-# through.
+# through.  The correct output is tied to preallocation strategy so it
+# has to be verified each time we change preallocation.
 #
 echo "== block writes into region allocs hole" 
 t_set_sysfs_mount_option 0 data_prealloc_blocks 8