Re: fishy ->put_inode usage in ntfs

[Anton Altaparmakov <aia21@cam.ac.uk>]

On Thu, 2005-02-10 at 11:47 +0100, Christoph Hellwig wrote:
> On Thu, Oct 14, 2004 at 02:26:45PM +0100, Anton Altaparmakov wrote:
> > > I don't like filesystem doings things like this in ->put_inode at all,
> > > and indeed the plan is to get rid of ->put_inode completely.  Why do
> > > you need to hold an additional reference anyway?  What's so special
> > > about the relation of these two inodes?
> > 
> > The bmp_ino is a virtual inode.  It doesn't exist on disk as an inode. 
> > It is an NTFS attribute of the base inode.  It cannot exist without the
> > base inode there.  You could neither read from nor write to this inode
> > without its base inode being there and you couldn't even clear_inode()
> > this inode without the base inode being there.  The reference is
> > essential I am afraid.
> > 
> > If ->put_inode is removed then I will have to switch to using
> > ntfs_attr_iget() each time or I will have to attach the inode in some
> > other much hackier way that doesn't use the i_count and uses my ntfs
> > private counter instead.
> 
> Coming back to this issue.  Why do you need to refcount bmp_ino at all?

I am not sure what you mean.  The VFS layer does reference counting on
inodes.  I have no choice in the matter.

> Can someone ever grab a reference separate from it's master inode?

Again, not sure what you mean.  Could you elaborate?

Best regards,

        Anton
-- 
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/