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From: Frederic Weisbecker on 21 May 2010 03:10
On Fri, May 21, 2010 at 08:25:32AM +0200, Arnd Bergmann wrote:
> On Friday 21 May 2010, Tyler Hicks wrote:
> > Lower filesystems that only implement unlocked_ioctl aren't being
> > passed ioctl calls because eCryptfs only checked for
> > lower_file->f_op->ioctl and returned -ENOTTY if it was NULL.
> >
> > eCryptfs shouldn't implement ioctl(), since it doesn't require the BKL.
> > Instead, unlocked_ioctl() should be used and vfs_ioctl() can be called
> > on the lower file since it handles locking, if necessary. This requires
> > vfs_ioctl() to be exported.
>
> Calling vfs_ioctl doesn't help you at all here, you could simply call
> the ->unlocked_ioctl function of the lower fs directly to do the same,
> because ->ioctl will be gone soon.



Yeah. Nothing is left pending in the fs tree wrt ioctl pushdown so this
is safe.



> You are howevers still missing a few calls that are done through do_vfs_ioctl
> or file_ioctl. To implement these, you need to add the file and super operations
> that these call and forward the functions to the lower fs.
>
> > +#ifdef CONFIG_COMPAT
> > +static long
> > +ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> > +{
> > + long rc = -ENOTTY;
> > + struct file *lower_file = NULL;
> > +
> > + if (ecryptfs_file_to_private(file))
> > + lower_file = ecryptfs_file_to_lower(file);
> > + if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl)
> > + rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
> > + return rc;
> > +}
> > +#endif
>
> You need to return -ENOIOCTLCMD here, not ENOTTY to cover the case where
> the lower file system does not have a ->compat_ioctl function but has its
> calls listed in fs/compat_ioctl.c.
>
> Arnd



Right.

So I'll drop the pushdown from my tree and let Tyler handle that.

Thanks.

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