Re: [PATCH 12/13] xfs: Don't revert allocated offset for forcealign

From: Darrick J. Wong
Date: Fri Jun 21 2024 - 15:14:10 EST


On Fri, Jun 21, 2024 at 10:05:39AM +0000, John Garry wrote:
> In xfs_bmap_process_allocated_extent(), for when we found that we could not
> provide the requested length completely, the mapping is moved so that we
> can provide as much as possible for the original request.
>
> For forcealign, this would mean ignoring alignment guaranteed, so don't do
> this.
>
> Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx>

Makes sense,
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>

--D

> ---
> fs/xfs/libxfs/xfs_bmap.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index ebeb2969b289..42f3582c1574 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -3492,11 +3492,15 @@ xfs_bmap_process_allocated_extent(
> * original request as possible. Free space is apparently
> * very fragmented so we're unlikely to be able to satisfy the
> * hints anyway.
> + * However, for an inode with forcealign, continue with the
> + * found offset as we need to honour the alignment hint.
> */
> - if (ap->length <= orig_length)
> - ap->offset = orig_offset;
> - else if (ap->offset + ap->length < orig_offset + orig_length)
> - ap->offset = orig_offset + orig_length - ap->length;
> + if (!xfs_inode_has_forcealign(ap->ip)) {
> + if (ap->length <= orig_length)
> + ap->offset = orig_offset;
> + else if (ap->offset + ap->length < orig_offset + orig_length)
> + ap->offset = orig_offset + orig_length - ap->length;
> + }
> xfs_bmap_alloc_account(ap);
> }
>
> --
> 2.31.1
>
>