diff --git a/src/add-ons/kernel/file_systems/ext2/ExtentStream.cpp b/src/add-ons/kernel/file_systems/ext2/ExtentStream.cpp
index 6b0ff308ba..c92b5b5e71 100644
--- a/src/add-ons/kernel/file_systems/ext2/ExtentStream.cpp
+++ b/src/add-ons/kernel/file_systems/ext2/ExtentStream.cpp
@@ -187,7 +187,7 @@ ExtentStream::Enlarge(Transaction& transaction, off_t& numBlocks)
 			TRACE("Enlarge() last %lld allocatedPos %lld\n",
 				last.PhysicalBlock() + last.Length(), fAllocatedPos);
 			if (last.PhysicalBlock() + last.Length() == fAllocatedPos
-				&& (last.Length() + allocated) <= 0xffff) {
+				&& (last.Length() + allocated) <= EXT2_EXTENT_MAX_LENGTH) {
 				if (stream != fStream) {
 					stream = (ext2_extent_stream *)cached.SetToWritable(
 						transaction, cached.BlockNumber());
diff --git a/src/add-ons/kernel/file_systems/ext2/ext2.h b/src/add-ons/kernel/file_systems/ext2/ext2.h
index 43ffc92519..25a8468e1a 100644
--- a/src/add-ons/kernel/file_systems/ext2/ext2.h
+++ b/src/add-ons/kernel/file_systems/ext2/ext2.h
@@ -330,6 +330,7 @@ struct ext2_data_stream {
 } _PACKED;
 
 #define EXT2_EXTENT_MAGIC			0xf30a
+#define EXT2_EXTENT_MAX_LENGTH		0x8000
 
 struct ext2_extent_header {
 	uint16 magic;