Re: [PATCH V2] xfs_io: Document shutdown -f

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Thu, May 10, 2018 at 11:10:30AM +0200, Carlos Maiolino wrote:
> Add help and manpage information for xfs_io shutdown -f
> 
> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> ---
> 
> V2:
> 	Add more detailed information about what shutdown command does
> 
>  io/shutdown.c     | 16 ++++++++++++++++
>  man/man8/xfs_io.8 | 16 +++++++++++++++-
>  2 files changed, 31 insertions(+), 1 deletion(-)
> 
> diff --git a/io/shutdown.c b/io/shutdown.c
> index 022a0e9a..8ac64d63 100644
> --- a/io/shutdown.c
> +++ b/io/shutdown.c
> @@ -47,6 +47,21 @@ shutdown_f(
>  	return 0;
>  }
>  
> +static void
> +shutdown_help(void)
> +{
> +	printf(_(
> +"\n"
> +" Shuts down the filesystem and prevents any further IO from occurring.\n"
> +"\n"
> +" With no arguments, shutdown will not attempt to flush completed transactions\n"
> +" to disk before marking the log as being shut down. Simulating an IO error\n"

"This simulates an IO error behavior." ?

Might also be worth mentioning that this simulates a system crash too?

> +" behavior.\n"
> +"\n"
> +" -f -- Flush completed transactions to disk before shut down.\n"
> +"\n"));
> +}
> +
>  void
>  shutdown_init(void)
>  {
> @@ -56,6 +71,7 @@ shutdown_init(void)
>  	shutdown_cmd.argmax = 1;
>  	shutdown_cmd.flags = CMD_NOMAP_OK | CMD_FLAG_ONESHOT | CMD_FLAG_FOREIGN_OK;
>  	shutdown_cmd.args = _("[-f]");
> +	shutdown_cmd.help = shutdown_help;
>  	shutdown_cmd.oneline =
>  		_("shuts down the filesystem where the current file resides");
>  
> diff --git a/man/man8/xfs_io.8 b/man/man8/xfs_io.8
> index c3ab532d..d4c28a0a 100644
> --- a/man/man8/xfs_io.8
> +++ b/man/man8/xfs_io.8
> @@ -1007,8 +1007,22 @@ Note \-\- this can be useful for exercising out of space behavior.
>  Only available in expert mode and requires privileges.
>  .TP
>  .BR shutdown " [ " \-f " ]"
> -Force the filesystem to shutdown (with or without flushing the log).
> +Force a shutdown of the filesystem, but keep consistency. It does not unmount

I would've thought we maintain metadata consistency no matter if we
flush the log or not, at least if the log is working correctly.

Perhaps shorten this to 'Force the filesystem to shut down.'?

--D

> +the filesystem, but prevents any other IO to happen on it.
>  Only available in expert mode and requires privileges.
> +.PP
> +.RS
> +By default, XFS will not attempt to flush completed transactions to disk before
> +marking the log as being shut down.
> +.RE
> +.RS 1.0i
> +.PD 0
> +.TP 0.4i
> +.B \-f
> +Force XFS to flush all completed transactions to disk before marking the log as
> +shut down.
> +.PD
> +.RE
>  .TP
>  .BR stat " [ " \-v "|" \-r " ]"
>  Selected statistics from
> -- 
> 2.14.3
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html