Re: [PATCH 01/13] ext4: correct offset of gdb backup in non meta_bg group to update_backups

[Theodore Ts'o]

On Thu, Jun 29, 2023 at 08:00:32PM +0800, Kemeng Shi wrote:
> Commit 0aeaa2559d6d5 ("ext4: fix corruption when online resizing a 1K
> bigalloc fs") found that primary superblock's offset in its group is not
> equal to offset of backup superblock in its group when block size is 1K
> and bigalloc is enabled. As group descriptor blocks are right after
> superblock, we can't pass block number of gdb to update_backups for
> the same reason.
> The root casue of the issue above is that leading 1K padding block is
> count as data block offset for primary block while backup block has
> no padding block offset in its group.
> Remove padding data block count to fix the issue for gdb backups.
> 
> For meta_bg case, update_backups treat blk_off as block number, do no
> conversion in this case.
> 
> Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>

Reviewed-by: Theodore Ts'o <tytso@xxxxxxx>