Before corruption:
[root@charon:andrew]# filefrag -v bla
Filesystem type is: 9123683e
File size of bla is 1048576 (256 blocks of 4096 bytes)
 ext:     logical_offset:        physical_offset: length:   expected: flags:
   0:        0..     255:          0..       255:    256:             last,unknown_loc,delalloc,eof
bla: 1 extent found


After corruption:

[root@charon:andrew]# filefrag -v bla
Filesystem type is: 9123683e
File size of bla is 1048576 (256 blocks of 4096 bytes)
bla: 0 extents found