Re: [v7] ext4: Add support FALLOC_FL_COLLAPSE_RANGE for fallocate

[Dave Chinner <david@fromorbit.com>]

On Wed, Apr 02, 2014 at 12:42:58PM -0400, Theodore Ts'o wrote:
> Some final testing luckily caught a bug in your patch.  I'll fix it
> up, but for future reference, it's important to check to see if the
> handle is valid (i.e., we are not in no-journal mode) before using any
> of the journalling functions.  Otherwise, you will crash if you try
> using the code path when the file system does not have a journal.
> 
> BTW, I would strongly recommend using the automated regression test
> system found at:
> 
> 	git://git.kernel.org/pub/scm/fs/ext2/xfstests-bld.git
> 
> It finds these sorts of problems very quickly.  After you build a
> kernel, running "kvm-xfstests -g quick" would have found the problem
> very quickly.  The fastest reproducer for the bug that I found is:
> "kvm-xfstests -c nojournal shared/001".

Hi Ted,

If you check the xfstests commit history, I think you'll find that
Namjae wrote the xfstests that triggered the failure you are
seeing.

You're just testing more esoteric configurations than most people do
- same as I do for XFS. We can't expect every developer to test
their code on every possible configuration before they submit
it.... ;)

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com