Re: [RFC PATCH 05/11] xfs: add inode on-disk VERITY flag

[Dave Chinner <david@fromorbit.com>]

On Tue, Dec 13, 2022 at 06:29:29PM +0100, Andrey Albershteyn wrote:
> Add flag to mark inodes which have fs-verity enabled on them (i.e.
> descriptor exist and tree is built).
.....
> 
>  static inline bool xfs_dinode_has_bigtime(const struct xfs_dinode *dip)
>  {
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index f08a2d5f96ad4..8d9c9697d3619 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -636,6 +636,8 @@ xfs_ip2xflags(
>  			flags |= FS_XFLAG_DAX;
>  		if (ip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE)
>  			flags |= FS_XFLAG_COWEXTSIZE;
> +		if (ip->i_diflags2 & XFS_DIFLAG2_VERITY)
> +			flags |= FS_VERITY_FL;
>  	}

Ah, attribute flag confusion - easy to do. xflags (FS_XFLAG*) are a
different set of (extended) flags than the standard VFS inode flags
(FS_*_FL).

To place the verity enabled state in the extended flags, you would
need to define FS_XFLAG_VERITY in include/uapi/linux/fs.h. You'll
also need to add the conversion from FS_VERITY_FL to FS_XFLAG_VERITY
to fileattr_fill_flags() and vice versa to fileattr_fill_xflags()

This will allow both the VFS inode flags UAPI and the
FS_IOC_FSGETXATTR extended flag API to see the inode has verity
enabled on it.

Once FS_XFLAG_VERITY is defined, changing the code in XFS to use it
directly instead of FS_VERITY_FL will result in everything working
correct throughout the code.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com