Re: [PATCH 1/1] xfs: fix buffer flushing during log unmount

Christoph Hellwig
2012-02-17T19:15:31Z

> Whenever there is a mount/unmount failure - there is a chance of calling the
> callbacks functions once - transaction ail mount pointer is destroyed. So, it results
> in NULL pointer exception followed by hang. So, before unmount of the log - flush all
> the pending buffers.

> void
> xfs_log_unmount(xfs_mount_t *mp)
> {
> + int error = 0;
> + /*
> + * Make sure all buffers have been flushed and completed before
> + * unmounting the log.
> + */
> + error = xfs_flush_buftarg(mp->m_ddev_targp, 1);
> + if (error)
> + cmn_err(CE_WARN, "%d busy buffers during log unmount.", error);
> + xfs_wait_buftarg(mp->m_ddev_targp);
> +

We do exactly that sequence before the xfs_log_unmount_write call on
umount. Care to explain what code in xfs_log_unmount_write would
require this to be called again?