[Unionfs] show your support for merging Unionfs in 2.6.25

[Erez Zadok]

This message is for all of you users of Unionfs, especially those who lurk
quietly and hopefully happily. :-) We need your help to show your support
for merging Unionfs (now in -mm) into 2.6.25.  Linux 2.6.24 will be out
soon, and shortly afterwards will be the time when new features get merged
in prior to 2.6.25-rc1 coming out.

I've posted my second set of unionfs patches to lkml and fsdevel, and cc'ed
Linus Torvalds, Al Viro, Christoph Hellwig, and Andrew Morton.  For those
who don't know, Al and Christoph maintain the VFS, and Andrew maintains -mm.
These postings were made at the request of Al Viro and Andrew Morton in
recent months.  In my posting I've suggested a merge of unionfs in 2.6.25.

Alas, Christoph was quick to respond here:

	<http://lkml.org/lkml/2008/1/10/207>

He basically said he doesn't like the whole idea of a standalone unioning
file system and prefers to see Union Mounts done at the VFS level.  I
responded to Christoph here:

	<http://lkml.org/lkml/2008/1/10/224>

I said that it'd take a long time to get Union Mounts as stable and as
feature-full as Unionfs.  Union Mounts will need a LOT of VFS-level changes
that I really believe will take years to reach the same level of maturity as
Unionfs.

Worse, the Union Mount people have no plans currently to support all of the
features which Unionfs supports *today*!  This means that even if Union
Mounts were available at the VFS level, many of you won't be to use it.  For
example:

- they don't plan to support multiple writable branches (last I checked)

- they don't plan to have persistent inode numbers (so you can't nfs export)

- they have to change lower file systems to support whiteouts, and you will
  only be able to Union Mount on those file systems.  Currently none of the
  lower file systems in Linux have whiteout support.

So folks, this is the time for you to show your support!  If you'd like to
see Unionfs merged into the mainline Linux kernel, then please join the
discussion on lkml and fsdevel, and say that you're using unionfs and would
like to see it merged, etc.  If Linus is convinced, he might just take
Unionfs in now.

Thank you in advance.

Erez, on behalf of the unionfs team.