Re: [PATCH] Btrfs: make sure to unblock the transaction when cleaning it up

[Josef Bacik <josef@redhat.com>]

On Thu, May 31, 2012 at 11:14:37AM -0400, Josef Bacik wrote:
> When a transaction aborts we can get stuck in places where tasks are waiting
> for the transaction to become unblocked.  So we need to unblock the
> transaction and wake up any waiters so they can exit properly.  Thanks,
> 
> Signed-off-by: Josef Bacik <josef@redhat.com>
> ---
>  fs/btrfs/transaction.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index 7aed0e8..1715afb 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -1204,9 +1204,16 @@ static void cleanup_transaction(struct btrfs_trans_handle *trans,
>  	WARN_ON(trans->use_count > 1);
>  
>  	spin_lock(&root->fs_info->trans_lock);
> +	cur_trans->blocked = 0;
>  	list_del_init(&cur_trans->list);
> +	if (root->fs_info->running_transaction == cur_trans) {
> +		root->fs_info->running_transaction = NULL;
> +		root->fs_info->trans_no_join = 0;
> +	}
>  	spin_unlock(&root->fs_info->trans_lock);
>  
> +	wake_up(&root->fs_info->transaction_wait);
> +
>  	btrfs_cleanup_one_transaction(trans->transaction, root);
>  
>  	put_transaction(cur_trans);
> -- 
> 1.7.7.6

Actually ignore this, the problem is btrfs_cleanup_one_transaction is just doing
waitqueue_active() which is racy, we need to fix it to wake_up, so I'll fix that
and send it along.  Thanks,

Josef