Re: [External] : Re: [PATCH v2 3/3] xfs: incorporate increased AGFL min requirement for minleft allocs

[Brian Foster <bfoster@redhat.com>]

On Fri, Aug 14, 2026 at 10:18:15AM -0500, Mark Tinguely wrote:
> On 8/14/26 9:47 AM, Brian Foster wrote:
> > On Fri, Aug 14, 2026 at 09: 15: 15AM -0500, Mark Tinguely wrote: > On 8/14/26 8: 57 AM, Brian Foster wrote: > > On Fri, Aug 14, 2026 at 09: 22: 39AM -0400, Brian Foster wrote: > > > Matt Fleming reports a filesystem shutdown due
> > 
> > 
> > On Fri, Aug 14, 2026 at 09:15:15AM -0500, Mark Tinguely wrote:
> > > On 8/14/26 8:57 AM, Brian Foster wrote:
> > > > On Fri, Aug 14, 2026 at 09:22:39AM -0400, Brian Foster wrote:
> > > > > Matt Fleming reports a filesystem shutdown due to inobt block
> > > > > allocation failure during sparse chunk allocation. Inode creation
> 
> 
> (deleted text)
> 
> > > 
> > > 
> > > thank you for the comment clarification.
> > > I was confused by that change.
> > > 
> > > Could you CC stable. We saw a version of this problem in Linux 5.15
> > > 
> > 
> > Sure, though I'm not sure how far back this will apply cleanly.
> > 
> > Curious.. was the instance you saw also an inobt alloc failure leading
> > to dirty trans cancel and shutdown, or something different but similar?
> > 
> > Brian
> > 
> 
> yes the v5.15 problem was a similar sparse inode chunk / inode btree insert failure.
> I admit that I did not have the numbers to realize why the inode btree insert failed.
> 

Ok.

> although this is a fundamental allocation flaw, the sparse inode chunk allocation
> seems to be the just right/wrong conditions to trigger it.
> 

I think that's probably right, but I had the Fixes: tag on v1 and
dropped it here just because I think it's kind of a tenuous connection
now. Re: the discussion on v1, presumably we could have the same thing
happen with bmap allocs and just not see the shutdown because those
allocs are usually more flexible and can fall back to different AGs.

Regardless, wrt stable I think it would be reasonable to target back to
the release that enabled sparse inodes (v4.2) since that's how this is
reproduced in practice, so it probably doesn't make much difference
either way.

Brian

> Fixes: 5419040fc0f3a xfs: introduce inode record hole mask for sparse inode chunks ??
> 
> thanks for the fix
> 
> Mark Tinguely
> 
> 
>