Re: [PATCH v3 3/6] xfs: report the error that made deferred work shut down the fs

["Darrick J. Wong" <djwong@kernel.org>]

On Mon, Aug 10, 2026 at 05:06:15PM -0600, Javier Tia wrote:
> When a deferred operation fails and shuts the filesystem down,
> xfs_defer_finish_noroll() reports neither the errno nor which operation
> originated it, so the log cannot tell a transient -ENOSPC from real
> corruption.  Report the operation type, errno and remaining reservation.
> 
> trace_xfs_defer_finish_error() runs after xfs_force_shutdown(), which
> BUGs under fs.xfs.panic_mask and so never fires for the first failure;
> move it ahead of the shutdown and mirror it to xfs_alert() for systems
> without tracing armed.  Capture the op name while the item is live (dfp
> is freed once its work list drains) and suppress the alert once the fs is
> already down.
> 
> Signed-off-by: Javier Tia <floss@jetm.me>
> ---
>  fs/xfs/libxfs/xfs_defer.c | 15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_defer.c b/fs/xfs/libxfs/xfs_defer.c
> index 75f0d37914d5..3152acdc335d 100644
> --- a/fs/xfs/libxfs/xfs_defer.c
> +++ b/fs/xfs/libxfs/xfs_defer.c
> @@ -656,6 +656,7 @@ xfs_defer_finish_noroll(
>  	struct xfs_trans		**tp)
>  {
>  	struct xfs_defer_pending	*dfp = NULL;
> +	const char			*what = "chain";
>  	int				error = 0;
>  	LIST_HEAD(dop_pending);
>  	LIST_HEAD(dop_paused);
> @@ -705,9 +706,17 @@ xfs_defer_finish_noroll(
>  				struct xfs_defer_pending, dfp_list);
>  		if (!dfp)
>  			break;
> +		what = dfp->dfp_ops->name;
>  		error = xfs_defer_finish_one(*tp, dfp);
>  		if (error && error != -EAGAIN)
>  			goto out_shutdown;
> +		/*
> +		 * A finished item is no longer a candidate for a later
> +		 * failure.  An -EAGAIN one is not finished, so it keeps the
> +		 * attribution across the roll that completes it.
> +		 */
> +		if (!error)
> +			what = "chain";
>  	}
>  
>  	/* Requeue the paused items in the outgoing transaction. */
> @@ -719,8 +728,12 @@ xfs_defer_finish_noroll(
>  out_shutdown:
>  	list_splice_tail_init(&dop_paused, &dop_pending);
>  	xfs_defer_trans_abort(*tp, &dop_pending);
> -	xfs_force_shutdown((*tp)->t_mountp, SHUTDOWN_CORRUPT_INCORE);
>  	trace_xfs_defer_finish_error(*tp, error);
> +	if (!xfs_is_shutdown((*tp)->t_mountp))
> +		xfs_alert((*tp)->t_mountp,
> +			  "deferred %s work failed, error %d, %u blocks reserved",
> +			  what, error, (*tp)->t_blk_res);

Excellent!  A new logging artifact that (might) tell us *which* deferred
operation produced an error. :)

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> +	xfs_force_shutdown((*tp)->t_mountp, SHUTDOWN_CORRUPT_INCORE);
>  	xfs_defer_cancel_list((*tp)->t_mountp, &dop_pending);
>  	xfs_defer_cancel(*tp);
>  	return error;
> -- 
> Javier Tia
> 
>