Messages in this thread | | | Subject | Re: GFS2 and DLM | From | Steven Whitehouse <> | Date | Fri, 23 Jun 2006 17:09:31 +0100 |
| |
Hi,
On Fri, 2006-06-23 at 16:54 +0100, Christoph Hellwig wrote: > On Fri, Jun 23, 2006 at 04:54:04PM +0100, Steven Whitehouse wrote: > > with just calling permission directly... we need to call it mainly because > > the VFS only does locking within a single node and we recheck the permissions > > in a few places after we've taken the glocks which provide cluster-wide > > exclusion. > > ->permission must give correct answers. So I think the answer to your question > is that you need to do the right thing there and get rid of the additional > calls. >
It does give correct answers. The point is that the answer might change between ->permission dropping its lock and the actual operation taking place since there is a time for which the lock is not held where other nodes might race. To get around this we recheck the permissions in GFS2 to ensure that nothing has changed,
Steve.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |