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Date: Tue, 7 Aug 2001 00:36:32 -0600
Message-Id: <200108070636.f776aWi31626@vindaloo.ras.ucalgary.ca>
From: Richard Gooch <rgooch@ras.ucalgary.ca>
To: Alexander Viro <viro@math.psu.edu>
Cc: Linus Torvalds <torvalds@transmeta.com>,
        Alan Cox <alan@lxorguk.ukuu.org.uk>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] one of $BIGNUM devfs races
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Alexander Viro writes:
> 
> 
> On Mon, 6 Aug 2001, Richard Gooch wrote:
> 
> > Damn. I've just run into a snag. My read_inode() needs to dereference
> > inode->u.generic_ip, however, I can only initialise this *after* the
> > call to iget() finishes. Now, I could shoehorn my pointer into
> > inode->ino (thanks to it being an unsigned long), but that's pretty
> > gross.
> > 
> > I also notice iget4() and the read_inode2() method, however, from the
> > comments, it looks like those are reiserfs-specific, and will die
> > soon. At the very least, it seems use thereof is discouraged.
> > 
> > Suggestions?
> 
> Lose ->read_inode(). Since your inode numbers are not stable across
> reboot you can't use iget for NFS-exporting devfs (even if you would
> want to export it in the first place). So there is no reason whatsoever
> to use it.

OK...

> Add put_inode: force_delete, into your super_operations and replace
> your call of iget() with
> 
> 	inode = new_inode(sb);
> 	if (inode) {
> 		inode->i_ino = whatever;
> 		/* stuff you've used to do in devfs_read_inode */
> 	}
> 
> Notice that here you have pointer to 'entry', so there is no problem
> with passing it. ->read_inode() simply goes away. Besides, that way
> you don't pollute icache hash chains - devfs inodes stay out of hash.

Um, what will happen to inode change events? What exactly is the
purpose of these hash chains?

				Regards,

					Richard....
Permanent: rgooch@atnf.csiro.au
Current:   rgooch@ras.ucalgary.ca