Re: [PATCH 0/5] btrfs-progs: check: properly skip preallocated/nodatasum extents when re-calculating csum tree

[Josef Bacik <josef@toxicpanda.com>]

On Fri, Dec 24, 2021 at 01:50:14PM +0800, Qu Wenruo wrote:
> Merry Christmas and happy new year!
> 
> [BUG]
> Issue #420 mentions that --init-csum-tree creates extra csum for
> preallocated extents.
> 
> Causing extra errors after --init-csum-tree.
> 
> [CAUSE]
> Csum re-calculation code doesn't take the following factors into
> consideration:
> 
> - NODATASUM inodes
> - Preallocated extents
>   No csum should be calculated for those data extents
> 
> - Partically written preallocated csum
>   Csum should only be created for the referred part
> 
> So currently csum recalculation will just create csum for any data
> extents it found, causing the mentioned errors.
> 
> [FIX]
> 
> - Bug fix for backref iteration
>   Firstly fix a bug in backref code where indirect ref is not properly
>   resolved.
> 
>   This allows us to use iterate_extent_inodes() to make our lives much
>   easier checking the file extents.
> 
> - Code move for --init-csum-tree
>   Move it to mode independent mode-common.[ch]
> 
> - Fix for --init-csum-tree
>   Using iterate_extent_inodes() to do that.
> 
> - Fix for --init-csum-tree --init-extent-tree
>   The same fix, just into a different context
> 
> - New test case
> 

Eesh that's not great.  Thanks for fixing this up,

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef