On Nov 7, 2022, at 5:21 AM, Ritesh Harjani (IBM) <ritesh.list@gmail.com> wrote:
> 
> This patch adds a test to verify the core bitmaps merge APIs
> for rbtree bitmap type.
> 
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>

Reviewed-by: Andreas Dilger <adilger@dilger.ca>

> +/*
> + * Note we use EXT2FS_BMAP64_BITARRAY always for used_bitmap, this is because
> + * EXT2FS_BMAP64_RBTREE does not support parallel scan due to rcursor
> + * optimization.
> + */

Is this going to be a problem in the future?  I think for pass1/pass5 there
are no rbtree bitmaps that are *source* bitmaps for multi-threaded operation,
but I suspect that once we try to parallelize pass2 this could break.

Is there any check in the code that prevents multi-thread access to an rbtree
bitmap?  Making a copy for each thread, or ideally copying the rcursor for
each thread, to allow at least multi-threaded reads.  I don't think there is
a high need for multi-threaded write

Cheers, Andreas