Re: [PATCH 2/4] vfs: create a generic checking function for FS_IOC_FSSETXATTR

[David Sterba]

On Tue, Jun 25, 2019 at 03:57:25AM -0700, Christoph Hellwig wrote:
> On Fri, Jun 21, 2019 at 04:56:29PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > 
> > Create a generic checking function for the incoming FS_IOC_FSSETXATTR
> > fsxattr values so that we can standardize some of the implementation
> > behaviors.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> > Reviewed-by: Jan Kara <jack@xxxxxxx>
> > ---
> >  fs/btrfs/ioctl.c   |   21 +++++++++-------
> >  fs/ext4/ioctl.c    |   27 ++++++++++++++------
> >  fs/f2fs/file.c     |   26 ++++++++++++++-----
> >  fs/inode.c         |   17 +++++++++++++
> >  fs/xfs/xfs_ioctl.c |   70 ++++++++++++++++++++++++++++++----------------------
> >  include/linux/fs.h |    3 ++
> >  6 files changed, 111 insertions(+), 53 deletions(-)
> > 
> > 
> > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> > index f408aa93b0cf..7ddda5b4b6a6 100644
> > --- a/fs/btrfs/ioctl.c
> > +++ b/fs/btrfs/ioctl.c
> > @@ -366,6 +366,13 @@ static int check_xflags(unsigned int flags)
> >  	return 0;
> >  }
> >  
> > +static void __btrfs_ioctl_fsgetxattr(struct btrfs_inode *binode,
> > +				     struct fsxattr *fa)
> > +{
> > +	memset(fa, 0, sizeof(*fa));
> > +	fa->fsx_xflags = btrfs_inode_flags_to_xflags(binode->flags);
> 
> Is there really much of a point in this helper? Epeciall as
> the zeroing could easily be done in the variable declaration
> line using
> 
> 	struct fsxattr fa = { };

Agreed, not counting the initialization the wrapper is merely another
name for btrfs_inode_flags_to_xflags. I also find it slightly confusing
that __btrfs_ioctl_fsgetxattr name is too close to the ioctl callback
implementation btrfs_ioctl_fsgetxattr but only does some initialization.