XFS assertion from truncate. (3.10-rc2)

[Dave Jones]

On Wed, May 22, 2013 at 03:51:47PM +1000, Dave Chinner wrote:

 > > Tomorrow I'll also try running some older kernels with the same
 > > options to see if it's something new, or an older bug. This is a
 > > new machine, so it may be something that's been around for a
 > > while, and for whatever reason, my other machines don't hit
 > > this.
 > 
 > Another thing that just occurred to me - what compiler are you
 > using?  We had a report last week on #xfs that xfsdump was failing
 > with bad checksums because of link time optimisation (LTO) in
 > gcc-4.8.0. When they turned that off, everything worked fine. So if
 > you are using 4.8.0, perhaps trying a different compiler might be a
 > good idea, too.

Yeah, this is 4.8.0. This box is running F19-beta. 
I managed to shoehorn the gcc-4.7 from f18 on there though.
Bug reproduced instantly, so I think we can rule out compiler.

I ran 3.9 with the same debug options. Seems stable.
I'll do a bisect.

	Dave