Re: [PATCH v5 3/3] btrfs: use buffer xarray for extent buffer writeback operations

[David Sterba <dsterba@suse.cz>]

On Mon, May 26, 2025 at 06:53:02AM +0000, Shinichiro Kawasaki wrote:
> On May 26, 2025 / 13:50, Qu Wenruo wrote:
> > 
> > 
> > 在 2025/5/26 10:47, Shinichiro Kawasaki 写道:
> > > On Apr 28, 2025 / 10:52, Josef Bacik wrote:
> > > > Currently we have this ugly back and forth with the btree writeback
> > > > where we find the folio, find the eb associated with that folio, and
> > > > then attempt to writeback.  This results in two different paths for
> > > > subpage eb's and >= pagesize eb's.
> > > > 
> > > > Clean this up by adding our own infrastructure around looking up tag'ed
> > > > eb's and writing the eb's out directly.  This allows us to unify the
> > > > subpage and >= pagesize IO paths, resulting in a much cleaner writeback
> > > > path for extent buffers.
> > > 
> > > [...]
> > > 
> > > When I ran blktests on the for-next kernel with the tag next-20250521, I
> > > observed the test case zdd/009 failed with repeated WARNs at
> > > release_extent_buffer() [1].
> > 
> > Unfortunately that's a known bug, fixed by this patch:
> > 
> > https://lore.kernel.org/linux-btrfs/b964b92f482453cbd122743995ff23aa7158b2cb.1747677774.git.josef@toxicpanda.com/
> > 
> 
> Ah, thank you for letting me know. I confirmed that the fix avoids the failure
> on my test system.

FYI, the fix is now in master.