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    SubjectRe: GFS2 and DLM
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    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.


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