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On Mon, Jun 25, 2007 at 11:01:23AM -0700, Bill Stouder-Studenmund wrote:
> On Mon, Jun 25, 2007 at 02:13:51PM +0100, Andrew Doran wrote:
> > Hi,
> >=20
> > One of the remaining problem areas in vfs wrt locking is the buffer cac=
he.
> > With vfs & ffs run without the kernel lock, eventually the system will
> > deadlock with one or more threads stuck in in biowait. So I guess that
> > somewhere the necessary locks are not being taken, and it's losing stat=
e.
> >=20
> > I've been looking into simplifying the locking, as it's unclear what's
> > covered by the long term lock (B_BUSY) and the short term lock
> > (b_interlock). One thing I'd like to do is replace b_interlock with a
> > pointer to the interlock for the vnode that the buffer is currently
> > associated with.

Thinking about this, what is the locking protocol for unassociating a=20
buffer with a vnode? Also, do we ever change association from one vnode to=
=20
another? If so, what protocol should we follow then?

Take care,

Bill

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