[dm-devel] dm-integrity: Fix flush with external metadata device
Mike Snitzer
snitzer at redhat.com
Mon Jan 4 20:30:42 UTC 2021
On Sun, Dec 20 2020 at 8:02am -0500,
Lukas Straub <lukasstraub2 at web.de> wrote:
> With an external metadata device, flush requests aren't passed down
> to the data device.
>
> Fix this by issuing flush in the right places: In integrity_commit
> when not in journal mode, in do_journal_write after writing the
> contents of the journal to the disk and in dm_integrity_postsuspend.
>
> Signed-off-by: Lukas Straub <lukasstraub2 at web.de>
> ---
> drivers/md/dm-integrity.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
> index 5a7a1b90e671..a26ed65869f6 100644
> --- a/drivers/md/dm-integrity.c
> +++ b/drivers/md/dm-integrity.c
> @@ -2196,6 +2196,8 @@ static void integrity_commit(struct work_struct *w)
> if (unlikely(ic->mode != 'J')) {
> spin_unlock_irq(&ic->endio_wait.lock);
> dm_integrity_flush_buffers(ic);
> + if (ic->meta_dev)
> + blkdev_issue_flush(ic->dev->bdev, GFP_NOIO);
> goto release_flush_bios;
> }
>
> @@ -2410,6 +2412,9 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned write_start,
> wait_for_completion_io(&comp.comp);
>
> dm_integrity_flush_buffers(ic);
> + if (ic->meta_dev)
> + blkdev_issue_flush(ic->dev->bdev, GFP_NOIO);
> +
> }
>
> static void integrity_writer(struct work_struct *w)
> @@ -2949,6 +2954,9 @@ static void dm_integrity_postsuspend(struct dm_target *ti)
> #endif
> }
>
> + if (ic->meta_dev)
> + blkdev_issue_flush(ic->dev->bdev, GFP_NOIO);
> +
> BUG_ON(!RB_EMPTY_ROOT(&ic->in_progress));
>
> ic->journal_uptodate = true;
> --
> 2.20.1
Seems like a pretty bad oversight... but shouldn't you also make sure to
flush the data device _before_ the metadata is flushed?
Mike
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