On Tue, Aug 20, 2024 at 07:04:57PM +0200, Christoph Hellwig wrote:
> Currently the debug-only xfs_bmap_exact_minlen_extent_alloc allocation
> variant fails to drop into the lowmode last restor allocator, and
last resort?
> thus can sometimes fail allocations for which the caller has a
> transaction block reservation.
>
> Fix this by using xfs_bmap_btalloc_low_space to do the actual allocation.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> fs/xfs/libxfs/xfs_bmap.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index b5eeaea164ee46..784dd5dda2a1a2 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -3493,7 +3493,13 @@ xfs_bmap_exact_minlen_extent_alloc(
> */
> ap->blkno = XFS_AGB_TO_FSB(ap->ip->i_mount, 0, 0);
>
> - return xfs_alloc_vextent_first_ag(args, ap->blkno);
> + /*
> + * Use the low space allocator as it first does a "normal" AG iteration
> + * and then drops the reservation to minlen, which might be required to
> + * find an allocation for the transaction reservation when the file
> + * system is very full.
Isn't it already doing a minlen allocation? Oh, that probably refers to
shrinking args->total, doesn't it.
If the answer to that is 'yes' then
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> + */
> + return xfs_bmap_btalloc_low_space(ap, args);
> }
> #else
>
> --
> 2.43.0
>
>
