Re: [PATCH 3/3] rbd: don't assume rbd_is_lock_owner() for exclusive mappings

[Dongsheng Yang <dongsheng.yang@linux.dev>]

在 2024/7/24 星期三 下午 2:29, Ilya Dryomov 写道:
> Expanding on the previous commit, assuming that rbd_is_lock_owner()
> always returns true (i.e. that we are either in RBD_LOCK_STATE_LOCKED
> or RBD_LOCK_STATE_QUIESCING) if the mapping is exclusive is wrong too.
> In case ceph_cls_set_cookie() fails, the lock would be temporarily
> released even if the mapping is exclusive, meaning that we can end up
> even in RBD_LOCK_STATE_UNLOCKED.
> 
> IOW, exclusive mappings are really "just" about disabling automatic
> lock transitions (as documented in the man page), not about grabbing
> the lock and holding on to it whatever it takes.

Hi Ilya,
	Could you explain more about "disabling atomic lock transitions"? To be 
honest, I was thinking --exclusive means "grabbing
the lock and holding on to it whatever it takes."

Thanx
> 
> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
> ---
>   drivers/block/rbd.c | 5 -----
>   1 file changed, 5 deletions(-)
> 
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index dc4ddae4f7eb..b8e6700d65f8 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -6589,11 +6589,6 @@ static int rbd_add_acquire_lock(struct rbd_device *rbd_dev)
>   	if (ret)
>   		return ret;
>   
> -	/*
> -	 * The lock may have been released by now, unless automatic lock
> -	 * transitions are disabled.
> -	 */
> -	rbd_assert(!rbd_dev->opts->exclusive || rbd_is_lock_owner(rbd_dev));
>   	return 0;
>   }
>   
>