Re: Inconsistency in sysfs behavior?

From: Greg KH
Date: Wed Jan 07 2004 - 16:57:38 EST


On Wed, Jan 07, 2004 at 04:50:24PM -0500, Alan Stern wrote:
> On Wed, 7 Jan 2004, Greg KH wrote:
>
> > Because it is very difficult to determine when a user goes into a
> > directory because we are using the ramfs/libfs code. It also does not
> > cause any errors if the kobject is removed, as the vfs cleans up
> > properly.
> >
> > Only when a file is opened does a kobject need to be pinned, due to
> > possible errors that could happen.
>
> I had in mind approaching this the opposite way. Instead of trying to
> make open directories also pin a kobject, why not make open attribute
> files not pin them?
>
> It shouldn't be hard to avoid any errors; in fact I had a patch from some
> time ago that would do the trick (although in a hacked-up kind of way).
> The main idea is to return -ENXIO instead of calling the show()/store()
> routines once the attribute has been removed.

And you can do this without adding another lock, race free?

greg k-h
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