And here is the test case.... BTW, #protip: You can use the split_node command in tst_extents debugging program not only to perform node splits (which will make the tree wider), but if you try splitting at the root node, it will allocate a new extent tree block, and then move all of the extent tree nodes at the top-level, in the inode, into the new exterior extent tree block. In effect, this will make the tree deeper. This should allow you to make fairly arbitrarily deep and complex extent trees by hand, without having to resort to using fallocate and punch hole commands, which tend to take a lot longer than using the "insert_extent", "replace_extent", and "split_node" commands in tst_extent when creating test cases. This also makes it easier to create small test file system images so we don't have to bloat the e2fsprogs source tree with huge test file systems in our regression test suite (which also tend to very much slow down running said regression test suite). Regards, - Ted