Re: Feature request: e2fsck -z

[Ted Ts'o <tytso@mit.edu>]

On Wed, Aug 10, 2011 at 07:34:46AM +0100, Ric Wheeler wrote:
> 
> Do you need it to be in the fsck tool?

As others have noted, (a) zerofree does this already, and (b) there's
also -E discard.

My take on it though is that it's a reasonable request.  It's much
like there is "sort -u" even though you could do this via "sort |
uniq".  Part of the Unix philosophy is to use tools that are
composable, yes --- but optimizing for common cases is also a good
thing, and with the advent of virtualization being more and more
popular, zeroing free blocks for virtualization images is good and
useful thing.

This is also why I agitated for adding support so that e2fsprogs tools
could operate directly on qemu-img files, and not just have support
which is hacked into e2image.  Yes, you can always take an qemu-img
file, decompress and expand it into a raw file, run debugfs or e2fsck
on it, and then convert it back to a qemu-img file --- but if lots of
people are doing that, it does make sense to optimize for the most
common use cases.

						- Ted