On Fri, Oct 21, 2011 at 01:28:57PM -0700, Simon Kirby wrote:
> > So we're waiting for the inode to be flushed, aka I/O again.
> 
> But I don't seem to see any queued I/O, hmm.

Well, as far as XFS is concerned the inode is beeing flushed and
the buffer is locked.  It could be stuck in the XFS internal delwri
list because a buffer for example is pinned.

If that is the case the big hammer patch I attached below - probably
not the final issue, but it should fix the hang if that is the case.

> > If this doesn't help I'll probably need to come up with some tracing
> > patches for you.
> 
> It seemes 3.0.7+gregkh's stable-queue queue-3.0 patches seems to be
> running fine without blocking at all on this SSD box, so that should
> narrow it down significantly.
> 
> Hmm, looking at git diff --stat v3.0.7..v3.1-rc10 fs/xfs , maybe not.. :)
> 
> Maybe 3.1 fs/xfs would transplant into 3.0 or vice-versa?

If the patch above doesn't work I'll prepare a backport for you.