On Tue, Dec 20, 2016 at 01:28:28PM -0500, jeffm@xxxxxxxx wrote:
> From: Jeff Mahoney <jeffm@xxxxxxxx>
>
> In __btrfs_run_delayed_refs, when we put back a delayed ref that's too
> new, we have already dropped the lock on locked_ref when we set
> ->processing = 0.
>
> This patch keeps the lock to cover that assignment.
>
> Fixes: d7df2c796d7 (Btrfs: attach delayed ref updates to delayed ref heads)
> Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
> ---
> fs/btrfs/extent-tree.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index d74adf1..930ac8e 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -2526,11 +2526,11 @@ static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
> if (ref && ref->seq &&
> btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
> spin_unlock(&locked_ref->lock);
> - btrfs_delayed_ref_unlock(locked_ref);
> spin_lock(&delayed_refs->lock);
> locked_ref->processing = 0;
> delayed_refs->num_heads_ready++;
> spin_unlock(&delayed_refs->lock);
> + btrfs_delayed_ref_unlock(locked_ref);
I don't think that this would end up a deadlock as we use mutex_try_lock
for head->mutex everywhere, but I'd rather have it cleaned up.
Reviewed-by: Liu Bo <bo.li.liu@xxxxxxxxxx>
Thanks,
-liubo
> locked_ref = NULL;
> cond_resched();
> count++;
> --
> 1.8.5.6
>
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