Re: [PATCH 5/8] xfs_db: check that metadata updates have been committed

[Brian Foster <bfoster@redhat.com>]

On Wed, Feb 19, 2020 at 05:42:13PM -0800, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@oracle.com>
> 
> Add a new function that will ensure that everything we scribbled on has
> landed on stable media, and report the results.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
>  db/init.c |   14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> 
> diff --git a/db/init.c b/db/init.c
> index 0ac37368..e92de232 100644
> --- a/db/init.c
> +++ b/db/init.c
> @@ -184,6 +184,7 @@ main(
>  	char	*input;
>  	char	**v;
>  	int	start_iocur_sp;
> +	int	d, l, r;
>  
>  	init(argc, argv);
>  	start_iocur_sp = iocur_sp;
> @@ -216,6 +217,19 @@ main(
>  	 */
>  	while (iocur_sp > start_iocur_sp)
>  		pop_cur();
> +
> +	libxfs_flush_devices(mp, &d, &l, &r);
> +	if (d)
> +		fprintf(stderr, _("%s: cannot flush data device (%d).\n"),
> +				progname, d);
> +	if (l)
> +		fprintf(stderr, _("%s: cannot flush log device (%d).\n"),
> +				progname, l);
> +	if (r)
> +		fprintf(stderr, _("%s: cannot flush realtime device (%d).\n"),
> +				progname, r);
> +
> +

Seems like we could reduce some boilerplate by passing progname into
libxfs_flush_devices() and letting it dump out of the error messages,
unless there's some future code that cares about individual device error
state.

That said, it also seems the semantics of libxfs_flush_devices() are a
bit different from convention. Just below we invoke
libxfs_device_close() for each device (rather than for all three), and
device_close() also happens to call fsync() and platform_flush_device()
itself...

Brian

>  	libxfs_umount(mp);
>  	if (x.ddev)
>  		libxfs_device_close(x.ddev);
>