Re: [PATCH v11 06/20] fsverity: don't allow setting DAX file attribute on fsverity files

[Eric Biggers <ebiggers@kernel.org>]

On Fri, Jul 10, 2026 at 10:52:34AM +0200, Andrey Albershteyn wrote:
> When fsverity is enabled on the file, with FS_IOC_ENABLE_VERITY ioctl(),
> it checks if file has DAX enabled and fails if that's true. However, the
> opposite case is not checked.
> 
> Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
> ---
>  fs/file_attr.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/fs/file_attr.c b/fs/file_attr.c
> index bfb00d256dd5..5424ec4e3949 100644
> --- a/fs/file_attr.c
> +++ b/fs/file_attr.c
> @@ -246,6 +246,11 @@ static int fileattr_set_prepare(struct inode *inode,
>  	if (fa->fsx_cowextsize == 0)
>  		fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
>  
> +	/* Can not enable DAX on fsverity file */
> +	if ((old_ma->fsx_xflags & FS_XFLAG_VERITY) &&
> +			fa->fsx_xflags & FS_XFLAG_DAX)
> +		return -EINVAL;
> +

This sounds like a bug fix.  But actually ext4 already checks this in
dax_compatible(), and the other filesystems that already supported
fsverity (f2fs and btrfs) don't support DAX.  So I guess this is really
lifting that to common code?  But the existing check is still being left
in place because it's still needed for ext4 specific flags anyway?

- Eric