Re: [PATCH v5 03/18] gfs2: add compat_ioctl support

[Arnd Bergmann]

On Fri, Aug 16, 2019 at 7:32 PM Andreas Gruenbacher <agruenba@xxxxxxxxxx> wrote:
>
> On Wed, Aug 14, 2019 at 10:45 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:
> > +       /* These are just misnamed, they actually get/put from/to user an int */
> > +       switch(cmd) {
> > +       case FS_IOC32_GETFLAGS:
> > +               cmd = FS_IOC_GETFLAGS;
> > +               break;
> > +       case FS_IOC32_SETFLAGS:
> > +               cmd = FS_IOC_SETFLAGS;
> > +               break;
>
> I'd like the code to be more explicit here:
>
>         case FITRIM:
>         case FS_IOC_GETFSLABEL:
>               break;
>         default:
>               return -ENOIOCTLCMD;

I've looked at it again: if we do this, the function actually becomes
longer than
the native gfs2_ioctl(). Should we just make a full copy then?

static long gfs2_compat_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
        switch(cmd) {
        case FS_IOC32_GETFLAGS:
                return gfs2_get_flags(filp, (u32 __user *)arg);
        case FS_IOC32_SETFLAGS:
                return gfs2_set_flags(filp, (u32 __user *)arg);
        case FITRIM:
                return gfs2_fitrim(filp, (void __user *)arg);
        case FS_IOC_GETFSLABEL:
                return gfs2_getlabel(filp, (char __user *)arg);
        }

        return -ENOTTY;
}

> Should we feed this through the gfs2 tree?

A later patch that removes the FITRIM handling from fs/compat_ioctl.c
depends on it, so I'd like to keep everything together.

         Arnd