Re: btrfs BUG on creating huge sparse file

Wu Fengguang
2009-04-29T11:46:21Z

On Wed, Apr 29, 2009 at 07:40:22PM +0800, Chris Mason wrote:
> On Wed, 2009-04-29 at 16:21 +0800, Wu Fengguang wrote:
> > On Wed, Apr 29, 2009 at 04:16:16PM +0800, Wu Fengguang wrote:
> > > On Thu, Apr 09, 2009 at 10:37:39AM -0400, Chris Mason wrote:
> > [snip]
> > > > PagePrivate is very common. try_to_releasepage failing on a clean page
> > > > without the writeback bit set and without dirty/locked buffers will be
> > > > pretty rare.
> > >
> > > Yup. btrfs seems to tag most(if not all) dirty pages with PG_private.
> > > While ext4 won't.
> >
> > Chris, I run into a btrfs BUG() when doing
> >
> > dd if=/dev/zero of=/b/sparse bs=1k count=1 seek=104857512345
> >
> > The half created sparse file is
> >
> > -rw-r--r-- 1 root root 98T 2009-04-29 14:54 /b/sparse
> > Or
> > -rw-r--r-- 1 root root 107374092641280 2009-04-29 14:54 /b/sparse
> >
> > Below is the kernel messages. I can test patches you throw at me :-)
> >
>
> How big was the FS you were testing this on? It works for me...

df says:

/dev/sda3 4.3G 28K 4.3G 1% /b

Oh bad, I cannot reproduce it now..

Thanks,
Fengguang