Re: [PATCH 11/21] fs: xfs: Don't use low-space allocator for alignment > 1

Dave Chinner
2023-10-03T01:16:35Z

On Fri, Sep 29, 2023 at 10:27:16AM +0000, John Garry wrote:
> The low-space allocator doesn't honour the alignment requirement, so don't
> attempt to even use it (when we have an alignment requirement).
>
> Signed-off-by: John Garry <john.g.garry@oracle.com>
> ---
> fs/xfs/libxfs/xfs_bmap.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index 30c931b38853..328134c22104 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -3569,6 +3569,10 @@ xfs_bmap_btalloc_low_space(
> {
> int error;
>
> + /* The allocator doesn't honour args->alignment */
> + if (args->alignment > 1)
> + return 0;
> +

How does this happen?

The earlier failing aligned allocations will clear alignment before
we get here....

-Dave.
--
Dave Chinner
david@fromorbit.com