On Wed, 2010-06-23 at 11:07 +0900, J. R. Okajima wrote:
> Ian Kent:
> > I may be missing something about this, but why is it safe to use
> > iterate_mounts(), since it doesn't take the vfsmount_lock when
> > traversing the list of mounts?
>
> The sample code was not correct.
> We need to acquire vfsmount_lock or down_read(namespace_sem).
>
> Or it may be better to extract the body of iterate_mounts() and create a
> new function __iterate_mounts() such like that.
>
> __iterate_mounts()
> {
> /* equiv to the current iterate_mounts */
> }
>
> iterate_mount()
> {
> down_read(namespace_sem);
> or spin_lock(&vfsmount_lock);
>
> __iterate_mount();
>
> spin_unlock(&vfsmount_lock);
> or up_read(namespace_sem);
> }
Yep, thought so.
That's a useful enough function to warrant that IMHO.
I'll continue checking its usages before I do it though.
Ian
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