call for brave ext4 testers in F9, with caveats

[Eric Sandeen]

Joachim Frieben wrote:
> I have been somehow forced to use ext4dev on my home partition for a few
> weeks now - caveat: after mounting it once there was no way to go back
> to ext3 without reformatting it - and I haven't noticed any anomaly. It
> actually seems to be already a valid drop-in replacement of ext3 right now.

At one point the rescue disk was "claiming" ext3 filesystems as ext4dev;
that was a bug that should be fixed now, and recent kernels have the
permanent upstream "failsafe check" to avoid that put into place*.  I'm
guessing that's what happened?  Although that bug was only with root
filesystems AFAIK.  Did you ever intentionally mount it as ext4dev?

As far as going back to ext3 - if you have extent-format files on the
filesystem, you can find them, mount with -o noextents, and copy the
files back & forth to "un-extentify" them, then we could use tune2fs to
remove the extents flag to get you back to ext3.  But if you've been
running /home as ext4dev for a while, it's probably got a lot of
extent-format files.

Also if you need to repair it, so far there is no released e2fsprogs
which can do that.  If you have an emergency let me know, and we'll get
something going.

But, good news you've not noticed any problems, even if it was not
intentional....

Thanks,
-Eric

* so, if your /home stops mounting after a kernel update, you will need
to get e2fsprogs-1.40.5 from rawhide, and do "tune2fs -E test_fs" on the
device to allow the kernel to mount it.