Re: [PATCH v3 0/3] btrfs: separate BLOCK_GROUP_TREE feature from extent-tree-v2

[David Sterba <dsterba@suse.cz>]

On Tue, Aug 23, 2022 at 10:01:06PM +0200, David Sterba wrote:
> On Tue, Aug 09, 2022 at 01:02:15PM +0800, Qu Wenruo wrote:
> > [Changelog]
> > v3:
> > - Add artificial requirement on fst and no-holes
> >   This is to address the concern from Josef on too many feature
> >   combinations.
> >   In fact I believe future features should also have hard requirement
> >   on the latest default features.
> > 
> > v2:
> > - Rebased to latest misc-next
> >   This fixes some random crash not related to btrfs.
> > 
> > - Fix some missing conversion due to bad branch
> >   I got my code messed up due to some bad local branch naming.
> >   The previous version sent to the ML lacks some essential conversion.
> > 
> >   Now it can properly pass full fstest run with block group tree.
> > 
> > This is the kernel part to revive block-group-tree feature.
> > 
> > Thanfully unlike btrfs-progs, the changes to kernel is much smaller, and
> > we can re-use most of the infrastructures from the extent-tree-v2
> > preparation patches.
> > 
> > But there are still some changes needed:
> > 
> > - Enhance unsupporter compat RO flags handling
> >   Extent tree is only needed for read-write opeartions, and for
> >   unsupported compat RO flags, we should not do any write into the fs.
> > 
> >   So this patch will make the kernel to skip block group items search
> >   if there is any unsupport RO compat flags.
> > 
> >   And really make the incoming block-group-tree feature compat RO.
> > 
> >   Unfortunately, we need that patch to be backported, or older kernels
> >   will still reject RO mounts of fses with block-group-tree feature.
> > 
> > - Don't store block group root into super block
> >   There is no special reason for block group root to be stored in super
> >   block.
> >   We should review those preparation patches with more scrutiny.
> > 
> > 
> > For the proper time reduction introduced by this patchset, the old data
> > should still be correct, as the on-disk format is not changed.
> > https://lwn.net/Articles/801990/
> > 
> > 
> > Qu Wenruo (3):
> >   btrfs: enhance unsupported compat RO flags handling
> >   btrfs: don't save block group root into super block
> >   btrfs: separate BLOCK_GROUP_TREE compat RO flag from EXTENT_TREE_V2
> 
> Adding this to for-next.

Moved to misc-next, thanks.