Date: Thu, 15 Apr 2004 15:02:32 -0700
From: Greg KH <greg@kroah.com>
To: viro@parcelfarce.linux.theplanet.co.uk
Cc: Maneesh Soni <maneesh@in.ibm.com>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] fix sysfs symlinks
Message-ID: <20040415220232.GC23039@kroah.com>
References: <20040413124037.GA21637@in.ibm.com> <20040413133615.GZ31500@parcelfarce.linux.theplanet.co.uk>
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On Tue, Apr 13, 2004 at 02:36:15PM +0100, viro@parcelfarce.linux.theplanet.co.uk wrote:
> On Tue, Apr 13, 2004 at 06:10:37PM +0530, Maneesh Soni wrote:
> > Hi,
> > 
> > As pointed by Al Viro, the current symlinks support in sysfs is incorrect as
> > it always sees the old target if target is renamed and obviously does not
> > follow the new target. The page symlink operations as used by current sysfs
> > code always see the target information at the time of creation. 
> 
> a) we ought to take a reference to target when creating a symlink (and drop
> it on removal)

No, we don't want that.  It's ok to have a dangling symlink in the fs if
the device the link was pointing to is now gone.  All of the struct
class_device stuff relies on the fact that a struct device can go away
at any time, and nothing bad will happen (with the exception of a stale
symlink.)

Yeah, it can cause a few odd looking trees when you unplug and replug a
device a bunch of times, all the while grabbing a reference to the class
device, but once everything is released by the user, it is cleaned up
properly, with no harm done to anything.

thanks,

greg k-h
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