On Monday April 28, akpm@xxxxxxxxxxxxxxxxxxxx wrote:
> On Tue, 29 Apr 2008 13:35:27 +1000 NeilBrown <neilb@xxxxxxx> wrote:
>
> >
> > From: Dan Williams <dan.j.williams@xxxxxxxxx>
> >
> > Found when trying to reassemble an active externally managed array.
> > Without this check we hit the more noisy "sysfs duplicate" warning in
> > the later call to kobject_add.
> >
> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> > Signed-off-by: Neil Brown <neilb@xxxxxxx>
> >
> > ### Diffstat output
> > ./drivers/md/md.c | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff .prev/drivers/md/md.c ./drivers/md/md.c
> > --- .prev/drivers/md/md.c 2008-04-29 12:27:57.000000000 +1000
> > +++ ./drivers/md/md.c 2008-04-29 12:27:57.000000000 +1000
> > @@ -1369,6 +1369,11 @@ static int bind_rdev_to_array(mdk_rdev_t
> > MD_BUG();
> > return -EINVAL;
> > }
> > +
> > + /* prevent duplicates */
> > + if (find_rdev(mddev, rdev->bdev->bd_dev))
> > + return -EEXIST;
> > +
> > /* make sure rdev->size exceeds mddev->size */
> > if (rdev->size && (mddev->size == 0 || rdev->size < mddev->size)) {
> > if (mddev->pers) {
>
> Smells racy. Do we have enough locking in place here to make this more
> than a best-effort thing?
Yes. We have exclusive access to the mddev at this point, so no race.
NeilBrown
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