[dm-devel] [PATCH 2/4] Fix a race between reading a new block and having it recycled.

[Mikulas Patocka]

Ack.

Mikulas

On Tue, 2 Aug 2011, Joe Thornber wrote:

> ---
>  drivers/md/persistent-data/dm-block-manager.c |    7 ++++++-
>  1 files changed, 6 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/md/persistent-data/dm-block-manager.c b/drivers/md/persistent-data/dm-block-manager.c
> index c9fb132..b68be88 100644
> --- a/drivers/md/persistent-data/dm-block-manager.c
> +++ b/drivers/md/persistent-data/dm-block-manager.c
> @@ -447,6 +447,7 @@ static int recycle_block(struct dm_block_manager *bm, dm_block_t where,
>  	 * Wait for a block to appear on the empty or clean lists.
>  	 */
>  	spin_lock_irqsave(&bm->lock, flags);
> +retry:
>  	while (1) {
>  		/*
>  		 * Once we can lock and do io concurrently then we should
> @@ -486,7 +487,11 @@ static int recycle_block(struct dm_block_manager *bm, dm_block_t where,
>  		spin_lock_irqsave(&bm->lock, flags);
>  		__wait_io(b, &flags);
>  
> -		/* FIXME: Can b have been recycled between io completion and here? */
> +		/*
> +		 * Has b been recycled whilst we were unlocked?
> +		 */
> +		if (b->where != where)
> +			goto retry;
>  
>  		/*
>  		 * Did the io succeed?
> -- 
> 1.7.4.1
>