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

[David Sterba]

On Wed, Apr 01, 2020 at 05:26:50AM +0200, 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.

IIRC the reason for the UAPI exports was to let strace use the includes
to decode the ioctls, so for that I agree it's improper to break the
build, sorry. The ioctls are a public interface so it's an ABI.  Patch
added to 5.7 queue, thanks.