Re: [PATCH v2 2/2] btrfs-progs: device delete to accept devid

[David Sterba <dsterba@suse.cz>]

On Wed, Sep 30, 2015 at 06:03:42AM +0800, Anand Jain wrote:
> +struct btrfs_ioctl_vol_args_v3 {

Can we use struct btrfs_ioctl_vol_args_v2 for that purpose? It contains
the 'flags' so we can abuse the name field to store the device id and
set the flags accordingly.

> +	__s64 fd;
> +	char name[BTRFS_PATH_NAME_MAX + 1];
> +	__u64 devid;
> +};
> +
>  #define BTRFS_DEVICE_PATH_NAME_MAX 1024
>  
>  #define BTRFS_SUBVOL_CREATE_ASYNC	(1ULL << 0)
> @@ -683,6 +689,8 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code)
>                                    struct btrfs_ioctl_feature_flags[2])
>  #define BTRFS_IOC_GET_SUPPORTED_FEATURES _IOR(BTRFS_IOCTL_MAGIC, 57, \
>                                    struct btrfs_ioctl_feature_flags[3])
> +#define BTRFS_IOC_RM_DEV_V2	_IOW(BTRFS_IOCTL_MAGIC, 58, \
> +				   struct btrfs_ioctl_vol_args_v3)

And we can reuse the ioctl nmuber 11

#define BTRFS_IOC_RM_DEV_V2	_IOW(BTRFS_IOCTL_MAGIC, 11, \
				   struct btrfs_ioctl_vol_args_v2)

The vol_v2 structure is extensible so we can add more functionality
there and then I think it justifies the V2 interface bump.