Re: [PATCH 7/7] writeback: splice dirty inode entries to default bdi on bdi_destroy()

Jens Axboe
2009-09-14T10:56:00Z

On Mon, Sep 14 2009, Jens Axboe wrote:
> We cannot safely ensure that the inodes are all gone at this point
> in time, and we must not destroy this bdi with inodes having off it.
> So just splice our entries to the default bdi since that one will
> always persist.
>
> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
> ---
> mm/backing-dev.c | 12 +++++++++++-
> 1 files changed, 11 insertions(+), 1 deletions(-)
>
> diff --git a/mm/backing-dev.c b/mm/backing-dev.c
> index fd93566..27f82dc 100644
> --- a/mm/backing-dev.c
> +++ b/mm/backing-dev.c
> @@ -668,7 +668,17 @@ void bdi_destroy(struct backing_dev_info *bdi)
> {
> int i;
>
> - WARN_ON(bdi_has_dirty_io(bdi));
> + /*
> + * Splice our entries to the default_backing_dev_info, if this
> + * bdi disappears
> + */
> + if (bdi_has_dirty_io(bdi)) {
> + struct bdi_writeback *dst = &default_backing_dev_info.wb;
> +
> + list_splice(&bdi->wb.b_dirty, &dst->b_dirty);
> + list_splice(&bdi->wb.b_io, &dst->b_io);
> + list_splice(&bdi->wb.b_more_io, &dst->b_more_io);
> + }

This needs locking, of course...

--
Jens Axboe