Online resizing of ext3 filesystems {shrink}

[goemon at anime.net]

On Sun, 8 Jan 2006, Bill Rugolsky Jr. wrote:
> Shrinking, on the other hand, presents a host of problems, including
> the need to compact the data below the new boundary, and deal with
> current users of the filesystem that may, e.g., have a region of
> some file memory-mapped, or may have I/O in flight.

what about if you're shrinking the filesystem to a point where nothing 
is/has ever been used/mapped and where no data needs to be compacted?

eg a 100gb filesystem where only 50gb has _ever_ been used.

> But nobody ever bothered to write the userland code for an online 
> defragmenter.

This is a major advantage microsoft has with NTFS over linux :-(

-Dan