Re: [PATCH v3] btrfs-progs: add verbose option to btrfs device scan

[Anand Jain <anand.jain@oracle.com>]

On 10/8/19 1:41 AM, David Sterba wrote:
> On Wed, Oct 02, 2019 at 12:11:52PM +0800, Anand Jain wrote:
>> To help debug device scan issues, add verbose option to btrfs device scan.
> 
> The common options like --verbose are going to be added into the global
> command so I'd rather avoid adding them to new subcommands as this would
> become unnecessary compatibility issue.

> There's an pattern to follow, the output formats (--format). So add a
> definition for global verbosity options, add new GETOPT_VAL global enum
> values that do not clash with existing options, add relevant
> HELPINFO_INSERT_ text string and use it in commands where needed.
> 

  IMO a debug option should rather be at the top level command.
  If verbose is the top level it would emit a lot of unwanted messages.
  Here is how a user is using --verbose option in dev scan.

 
https://lore.kernel.org/linux-btrfs/2daf15de-d1e7-b56a-be51-a6a3062ad28a@oracle.com/T/#t

------------
useful to get the list of devices it finds.
------------

  OR I didn't get the whole idea here. Looks like you are suggesting
  something like

   btrfs --verbose device scan
   btrfs --verbose subvolume list <mnt>
   ::

  How does the user will know if a subcommand will have any verbose
  or not?

  How would you not emit unwanted messages and keep the output clutter
  free.


Thanks, Anand