Re: [PATCH 1/6] hfsplus: prevent btree data loss on root split

Ernesto A. Fernández
2018-09-02T08:47:37Z

On Sat, Sep 01, 2018 at 02:49:26PM +1000, Dave Chinner wrote:
> On Fri, Aug 31, 2018 at 11:55:54AM -0300, Ernesto A. Fernández wrote:
> > On Thu, Aug 30, 2018 at 10:36:42PM -0700, Christoph Hellwig wrote:
> > > On Fri, Aug 31, 2018 at 12:58:19AM -0300, Ernesto A. Fernández wrote:
> > > > Creating, renaming or deleting a file may cause catalog corruption and
> > > > data loss. This bug is randomly triggered by xfstests generic/027, but
> > > > here is a faster reproducer:
> > > >
> > > > truncate -s 50M fs.iso
> > > > mkfs.hfsplus fs.iso
> > > > mount fs.iso /mnt
> > > > i=100
> > > > while [ $i -le 150 ]; do
> > > > touch /mnt/$i &>/dev/null
> > > > ((++i))
> > > > done
> > > > i=100
> > > > while [ $i -le 150 ]; do
> > > > mv /mnt/$i /mnt/$(perl -e "print $i x82") &>/dev/null
> > > > ((++i))
> > > > done
> > > > umount /mnt
> > > > fsck.hfsplus -n fs.iso
> > >
> > > It would be good to wire up this short reproducer as well for xfstests.
> >
> > Yes, that's my intention. The problem is that mkfs.hfsplus does not allow
> > setting the size of the filesystem for scratch_mkfs_sized(); you need a
> > workaround with the device mapper. I think I should submit that patch first
> > and see if there is a problem with it.
>
> You don't need to do that. We use loop devices like this w/ mkfs_dev
> quite a lot in fstests. For example, generic/361 has pretty much the
> exact code pattern you need....

I see what you mean in this case, but I really want to run every test that
uses _scratch_mkfs_sized(); generic/027 in particular, since it's the one
that found these bugs for me.

>
> Cheers,
>
> Dave.
>
>
> --
> Dave Chinner
> david@fromorbit.com