Re: [PATCH] btrfs: re-instantiate the removed BTRFS_SUBVOL_CREATE_ASYNC definition

[Nikolay Borisov]

On 1.04.20 Ð. 6:26 Ñ., Eugene Syromiatnikov wrote:
> The commit 9c1036fdb1d1ff1b ("btrfs: Remove BTRFS_SUBVOL_CREATE_ASYNC
> support") breaks strace build with the kernel headers from git:
> 
>     btrfs.c: In function "btrfs_test_subvol_ioctls":
>     btrfs.c:531:23: error: "BTRFS_SUBVOL_CREATE_ASYNC" undeclared (first use
>     in this function)
>        vol_args_v2.flags = BTRFS_SUBVOL_CREATE_ASYNC;
> 
> Moreover, it is improper to break UAPI anyway.
> 
> Restore the macro definition and put it under "#ifndef __KERNEL__"
> in order to prevent inadvertent in-kernel usage.
> 
> Fixes: 9c1036fdb1d1ff1b ("btrfs: Remove BTRFS_SUBVOL_CREATE_ASYNC support")
> Signed-off-by: Eugene Syromiatnikov <esyr@xxxxxxxxxx>

Ops, sorry about that:

Reviewed-by: Nikolay Borisov <nborisov@xxxxxxxx>

> ---
>  include/uapi/linux/btrfs.h | 10 ++++------
>  1 file changed, 4 insertions(+), 6 deletions(-)
> 
> diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
> index 8134924..e6b6cb0f 100644
> --- a/include/uapi/linux/btrfs.h
> +++ b/include/uapi/linux/btrfs.h
> @@ -36,12 +36,10 @@ struct btrfs_ioctl_vol_args {
>  #define BTRFS_DEVICE_PATH_NAME_MAX	1024
>  #define BTRFS_SUBVOL_NAME_MAX 		4039
>  
> -/*
> - * Deprecated since 5.7:
> - *
> - * BTRFS_SUBVOL_CREATE_ASYNC	(1ULL << 0)
> - */
> -
> +#ifndef __KERNEL__
> +/* Deprecated since 5.7 */
> +# define BTRFS_SUBVOL_CREATE_ASYNC	(1ULL << 0)
> +#endif
>  #define BTRFS_SUBVOL_RDONLY		(1ULL << 1)
>  #define BTRFS_SUBVOL_QGROUP_INHERIT	(1ULL << 2)
>  
>