[linux-lvm] How does LVM2 wrap up a filesystem?

[Dan Stromberg <strombrg dcs nac uci edu>]

When you have a filesystem in LVM2, are the ext3 blocks within
contiguous sometimes - say, if you haven't rearranged things, by adding,
removing, migrating things?

If it's possible that an ext3 might be a normal ext3 image, beyond some
offset from the beginning of a partition due to LVM2 wrapping (I'm
thinking like how TCP is wrapped up in an ethernet frame), at what
offset does the ext3 filesystem begin within the LVM2 partition?

Thanks!