Re: [linux-next:master] [btrfs] 9a8eec6165: fio.write_iops 22.6% regression

hi, Leo,

On Wed, Jul 01, 2026 at 04:44:11PM -0700, Leo Martins wrote:
> Hi Oliver,
> 
> Thanks for the report. I'm aware of this regression and the cause is
> understood: the flagged commit adds a per-COW xarray store on every
> COW'd metadata block, and on this single-task 4k randwrite ftruncate
> workload that store is what costs the write_iops.
> 
> A fix has been posted to linux-btrfs that replaces the xarray with a
> non-allocating fixed inline buffer and recovers the lost throughput:
> 
>   "btrfs: replace writeback inhibition xarray with a fixed inline buffer"
> 
> It carries the Reported-by and Closes tags pointing at this report.

thanks a lot for information! it's always our great pleasure that our reports
are helpful :)

> 
> Thanks,
> Leo