Re: [External] : [PATCH 1/2] xfs: set minleft correctly for sparse chunk errortag allocation

On 7/31/26 11:33 AM, Brian Foster wrote:
> The errortag instrumentation for forced sparse chunk allocation
> jumps straight to the allocation path without setting args.minleft.
> minleft is unconditionally set to ->inobt_maxlevels for the normal
> allocation path. Lift the assignment to the initial args setup so
> it covers all possible paths.
> 
> Assisted-by: LLM
> Fixes: 1cdadee11f8d ("xfs: randomly do sparse inode allocations in DEBUG mode")
> Signed-off-by: Brian Foster <[email protected]>
> ---
>   fs/xfs/libxfs/xfs_ialloc.c | 10 ++++------
>   1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_ialloc.c b/fs/xfs/libxfs/xfs_ialloc.c
> index ffcdd1f691fd..633b2d6e42c5 100644
> --- a/fs/xfs/libxfs/xfs_ialloc.c
> +++ b/fs/xfs/libxfs/xfs_ialloc.c
> @@ -733,6 +733,10 @@ xfs_ialloc_ag_alloc(
>   							igeo->maxicount)
>   		return -ENOSPC;
>   	args.minlen = args.maxlen = igeo->ialloc_blks;
> +
> +	/* Allow space for the inode btree to split. */
> +	args.minleft = igeo->inobt_maxlevels;
> +
>   	/*
>   	 * First try to allocate inodes contiguous with the last-allocated
>   	 * chunk of inodes.  If the filesystem is striped, this will fill
> @@ -764,8 +768,6 @@ xfs_ialloc_ag_alloc(
>   		args.alignment = 1;
>   		args.minalignslop = igeo->cluster_align - 1;
>   
> -		/* Allow space for the inode btree to split. */
> -		args.minleft = igeo->inobt_maxlevels;
>   		error = xfs_alloc_vextent_exact_bno(&args,
>   				xfs_agbno_to_fsb(pag, args.agbno));
>   		if (error)
> @@ -804,10 +806,6 @@ xfs_ialloc_ag_alloc(
>   		 * Allocate a fixed-size extent of inodes.
>   		 */
>   		args.prod = 1;
> -		/*
> -		 * Allow space for the inode btree to split.
> -		 */
> -		args.minleft = igeo->inobt_maxlevels;
>   		error = xfs_alloc_vextent_near_bno(&args,
>   				xfs_agbno_to_fsb(pag,
>   					be32_to_cpu(agi->agi_root)));


Reviewed-by: Mark Tinguely <[email protected]>

I got the patches backwards...I agree we need to increase the minleft in
the other patch by 4 blocks (2 btrees * 2 for the level increase) but I
wonder why can't a full size inode chunk also split the by-count and
by-block btrees and the inode btree allocation also be short when fixing AGFL?