Re: [PATCH 1/2 v2] btrfs: fix error handling when run_delayed_extent_op fails

[Liu Bo <bo.li.liu@oracle.com>]

On Tue, Dec 20, 2016 at 01:28:27PM -0500, jeffm@suse.com wrote:
> From: Jeff Mahoney <jeffm@suse.com>
> 
> In __btrfs_run_delayed_refs, the error path when run_delayed_extent_op
> fails sets locked_ref->processing = 0 but doesn't re-increment
> delayed_refs->num_heads_ready.  As a result, we end up triggering
> the WARN_ON in btrfs_select_ref_head.
> 
> Fixes: d7df2c796d7 (Btrfs: attach delayed ref updates to delayed ref heads)
> Reported-by: Jon Nelson <jnelson-suse@jamponi.net>
> Signed-off-by: Jeff Mahoney <jeffm@suse.com>
> ---
>  fs/btrfs/extent-tree.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index db74889..d74adf1 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -2576,7 +2576,10 @@ static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
>  					 */
>  					if (must_insert_reserved)
>  						locked_ref->must_insert_reserved = 1;
> +					spin_lock(&delayed_refs->lock);
>  					locked_ref->processing = 0;
> +					delayed_refs->num_heads_ready++;
> +					spin_unlock(&delayed_refs->lock);

Looks good to me.

Reviewed-by: Liu Bo <bo.li.liu@oracle.com>

Thanks,

-liubo
>  					btrfs_debug(fs_info,
>  						    "run_delayed_extent_op returned %d",
>  						    ret);
> -- 
> 1.8.5.6
> 
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