Re: [PATCH 6/6] xfs: bail out on bitmap errors in xrep_agfl_fill

[Carlos Maiolino <cem@kernel.org>]

On Thu, Sep 03, 2026 at 11:27:19PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> LOLLM also points out that the xagb_bitmap_set call in xrep_agfl_fill
> can fail, but we don't check the result of xagb_bitmap_walk, so we
> silently drop the error and proceed with inconsistent incore data.
> That shouldn't be allowed.

Looks good.

> 
> While we're at it, fix leaking the used_extents bitmap if the disunion
> operation fails.

Smells this description belongs to the previous patch?

> 
> Cc: <stable@vger.kernel.org> # v6.6
> Fixes: 014ad53732d2ba ("xfs: use per-AG bitmaps to reap unused AG metadata blocks during repair")
> Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
> Assisted-by: LOLLM # finding obvious bugs
> ---
>  fs/xfs/scrub/agheader_repair.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> 
> diff --git a/fs/xfs/scrub/agheader_repair.c b/fs/xfs/scrub/agheader_repair.c
> index 46c95354ca6438..a66b611588c47f 100644
> --- a/fs/xfs/scrub/agheader_repair.c
> +++ b/fs/xfs/scrub/agheader_repair.c
> @@ -699,7 +699,9 @@ xrep_agfl_init_header(
>  	 */
>  	xagb_bitmap_init(&af.used_extents);
>  	af.agfl_bno = xfs_buf_to_agfl_bno(agfl_bp);
> -	xagb_bitmap_walk(agfl_extents, xrep_agfl_fill, &af);
> +	error = xagb_bitmap_walk(agfl_extents, xrep_agfl_fill, &af);
> +	if (error && error != -ECANCELED)
> +		goto err_undo;
>  	error = xagb_bitmap_disunion(agfl_extents, &af.used_extents);
>  	if (error)
>  		goto err_undo;
> 
>