Re: [PATCH] Btrfs: fix chunk allocate size calculation

[Chris Mason <chris.mason@oracle.com>]

On Tue, Apr 06, 2010 at 03:54:27PM +0800, Yan, Zheng  wrote:
> On Thu, Mar 18, 2010 at 4:45 AM, Josef Bacik <josef@redhat.com> wrote=
:
> > If the amount of free space left in a device is less than what we t=
hink should
> > be the minimum size, just ignore the minimum size and use the amoun=
t we have. =A0I
> > ran into this running tests on a 600mb volume, the chunk allocator =
wouldn't let
> > me allocate the last 52mb of the disk for data because we want to h=
ave at least
> > 64mb chunks for data. =A0This patch fixes that problem. =A0Thanks,
> >
> > Signed-off-by: Josef Bacik <josef@redhat.com>
> >
> > diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> > index 9df8e3f..1c5b5ba 100644
> > --- a/fs/btrfs/volumes.c
> > +++ b/fs/btrfs/volumes.c
> > @@ -2244,8 +2244,10 @@ again:
> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0do_div(calc_size, stripe_len);
> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0calc_size *=3D stripe_len;
> > =A0 =A0 =A0 =A0}
> > +
> > =A0 =A0 =A0 =A0/* we don't want tiny stripes */
> > - =A0 =A0 =A0 calc_size =3D max_t(u64, min_stripe_size, calc_size);
> > + =A0 =A0 =A0 if (!looped)
> > + =A0 =A0 =A0 =A0 =A0 =A0 =A0 calc_size =3D max_t(u64, min_stripe_s=
ize, calc_size);
> >
> > =A0 =A0 =A0 =A0do_div(calc_size, stripe_len);
> > =A0 =A0 =A0 =A0calc_size *=3D stripe_len;
>=20
> I encountered an Oops caused by 'calc_size =3D=3D 0'. It's likely int=
roduced
> by this change. (calc_size can be zero after calling do_div)

Ok, thanks will fix it up.

-chris

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