Re: FileFallocate misbehaving on XFS

On Thu, Feb 5, 2026 at 8:16 PM Jakub Wartak
<jakub(dot)wartak(at)enterprisedb(dot)com> wrote:
> FWIW, I just learned yesterday that we went full circle on this:
> Redhat has published [1] "XFS fallocate(2) returning ENOSPC
> prematurely" several months ago. It references "commit
> 6773da870ab89123d1b513da63ed59e32a29cb77" titled "xfs: fix error
> returns from xfs_bmapi_write" , so folks just need to update to proper
> kernels. In addition we can do now:
> postgresql_discovering_linux_kernel_bugs++. Quick search also shows
> that e.g. linux-stable 6.1.x got it in 6.1.138 around May 2025, so
> probably all kernels released before are all affected.
>
> This pretty much matches the observation made earlier that it was
> mainly hit by people upgrading databases on the same host without
> updating OS/reinstalling hardware (re-using the older kernel).

Good news. We had no hope of reproducing this, our kernels were fixed
:-). I can't read the paywalled article but the top mentions kernels
back to 4.18 (RHEL 8). Should be everywhere by now.

> BTW: from our side we also have workaround patch (with GUC for this)
> solving 2nd problem and that is pending for inclusion in separate
> thread[2]

Yeah, I'll push 0001 shortly to get it into the minor releases before
the freeze, as it's still useful for the BTRFS people. With this new
info I can improve the reference to unexplained XFS failures in the
commit message. Thanks!