Re: [PATCH 6/6] btrfs: metadata_uuid: move partly logic into find_fsid_inprogress()

[Nikolay Borisov <nborisov@suse.com>]

On 12.12.19 г. 13:01 ч., damenly.su@gmail.com wrote:
> From: Su Yue <Damenly_Su@gmx.com>
> 
> The partly logic can be moved into find_fsid_inprogress() to
> make code for fs_devices finding looks more elegant.
> 
> Signed-off-by: Su Yue <Damenly_Su@gmx.com>

Code-wise the change is correct, on the other hand it's overloading what
find_fsid_inprogress handles. I did this to make it explicitly clear
what functions are called in what case as this code is somewhat tricky.

David, do you think this change is worth it.

> ---
>  fs/btrfs/volumes.c | 16 ++++------------
>  1 file changed, 4 insertions(+), 12 deletions(-)
> 
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index b21ab45e76a0..7e05f96b1575 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -636,6 +636,7 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices,
>  /*
>   * Handle scanned device having its CHANGING_FSID_V2 flag set and the fs_devices
>   * being created with a disk that has already completed its fsid change.
> + * Or it might belong to fs with no UUID changes in effect, handle both.
>   */
>  static struct btrfs_fs_devices *find_fsid_inprogress(
>  					struct btrfs_super_block *disk_super)
> @@ -651,7 +652,7 @@ static struct btrfs_fs_devices *find_fsid_inprogress(
>  		}
>  	}
>  
> -	return NULL;
> +	return find_fsid(disk_super->fsid, NULL);
>  }
>  
>  static struct btrfs_fs_devices *find_fsid_changed(
> @@ -795,19 +796,10 @@ static noinline struct btrfs_device *device_list_add(const char *path,
>  	*new_device_added = false;
>  
>  	if (fsid_change_in_progress) {
> -		if (!has_metadata_uuid) {
> -			/*
> -			 * When we have an image which has CHANGING_FSID_V2 set
> -			 * it might belong to either a filesystem which has
> -			 * disks with completed fsid change or it might belong
> -			 * to fs with no UUID changes in effect, handle both.
> -			 */
> +		if (!has_metadata_uuid)
>  			fs_devices = find_fsid_inprogress(disk_super);
> -			if (!fs_devices)
> -				fs_devices = find_fsid(disk_super->fsid, NULL);
> -		} else {
> +		else
>  			fs_devices = find_fsid_changed(disk_super);
> -		}
>  	} else if (has_metadata_uuid) {
>  		fs_devices = find_fsid_changing_metada_uuid(disk_super);
>  	} else {
>