Re: [PATCH 4/8] btrfs: cleanup the target logic in __btrfs_block_rsv_release

From: Nikolay Borisov <nborisov@suse.com>
To: Josef Bacik <josef@toxicpanda.com>, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 4/8] btrfs: cleanup the target logic in __btrfs_block_rsv_release
Date: Thu, 20 Jun 2019 11:23:36 +0300	[thread overview]
Message-ID: <3e9708a2-7316-08a4-6cb3-d81842e9b2ab@suse.com> (raw)
In-Reply-To: <20190619174724.1675-5-josef@toxicpanda.com>

On 19.06.19 г. 20:47 ч., Josef Bacik wrote:
> This works for all callers already, but if we wanted to use the helper
> for the global_block_rsv it would end up trying to refill itself.  Fix
> the logic to be able to be used no matter which block rsv is passed in
> to this helper.
> 
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> ---
>  fs/btrfs/extent-tree.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index d6aff56337aa..6995edf887e1 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -4684,12 +4684,20 @@ u64 __btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
>  {
>  	struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
>  	struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_refs_rsv;
> -	struct btrfs_block_rsv *target = delayed_rsv;
> +	struct btrfs_block_rsv *target = NULL;
>  
> -	if (target->full || target == block_rsv)
> +	/*
> +	 * If we are the delayed_rsv then push to the global rsv, otherwise dump
> +	 * into the delayed rsv if it is not full.
> +	 */
> +	if (block_rsv == delayed_rsv) {
>  		target = global_rsv;
> +	} else if (block_rsv != global_rsv) {
> +		if (!delayed_rsv->full)
> +			target = delayed_rsv;
> +	}

nit:

} else if (block_rsv != global_rsv && !delayed_rs->full) {

doesn't surpass the 80 character limit and IMO makes it a bit more
readable but it's minor.

Otherwise looks good.

>  
> -	if (block_rsv->space_info != target->space_info)
> +	if (target && block_rsv->space_info != target->space_info)
>  		target = NULL;
>  
>  	return block_rsv_release_bytes(fs_info, block_rsv, target, num_bytes,
> 