Re: [PATCH] Only honor the FIGETBSZ ioctl for regular files,directories, and symlinks

From: tytso
Date: Mon Jun 14 2010 - 10:13:02 EST


On Mon, Jun 14, 2010 at 10:07:30AM -0400, Christoph Hellwig wrote:
> On Mon, Jun 14, 2010 at 10:05:10AM -0400, Theodore Ts'o wrote:
> > FIGETBSZ has an ioctl number of _IO(0x00,2) == 2, which can conflict
> > with device driver ioctls. Let's avoid the potential for problems by
> > only honoring the ioctl number for files where this ioctl is likely
> > going to be useful: regular files, directories, and symlinks.
> >
> > Thanks to Johannes Stezenbach for pointing this consequence of commit
> > 19ba0559.
>
> ioctl operate on a file descriptor, so you never call them on
> symbolic links.

Oops, good point.

> A comment explaining why we fall through here for special files is
> almost required. Without that the chance of breaking it during the
> next random cleanup are far too high.

Sigh. I had fixed that, but I failed to save emacs buffer before
creating commit. Will resend with both fixes.

- Ted
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