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

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

[Josef Bacik]

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

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

[Josef Bacik]

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