Re: [PATCH v2 2/2] Btrfs: snapshot-aware defrag

[Josef Bacik <jbacik@fusionio.com>]

On Wed, Sep 05, 2012 at 07:10:52PM -0600, Liu Bo wrote:
> This comes from one of btrfs's project ideas,
> As we defragment files, we break any sharing from other snapshots.
> The balancing code will preserve the sharing, and defrag needs to grow this
> as well.
> 
> Now we're able to fill the blank with this patch, in which we make full use of
> backref walking stuff.
> 
> Here is the basic idea,
> o  set the writeback ranges started by defragment with flag EXTENT_DEFRAG
> o  at endio, after we finish updating fs tree, we use backref walking to find
>    all parents of the ranges and re-link them with the new COWed file layout by
>    adding corresponding backrefs.
> 
> Original-Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> ---
> v2: rebase against the latest btrfs-repo
> 

Heh well it doesn't apply onto btrfs-next, try again please :).  Thanks,

Josef