Re: [PATCH 2/2] btrfs-progs: add support for tabular format for device stats

[David Sterba <dsterba@suse.cz>]

On Mon, Jul 18, 2022 at 02:34:39PM +0300, Nikolay Borisov wrote:
> Add support for the -T switch to 'device stats" command such that
> executing 'btrfs device stats -T' produces:
> 
> Id Path     Write errors Read errors Flush errors Corruption errors Generation errors
> -- -------- ------------ ----------- ------------ ----------------- -----------------
>  1 /dev/vdc            0           0            0                 0                 0
>  2 /dev/vdd            0           0            0                 0                 0
> 
> Link: https://lore.kernel.org/linux-btrfs/d7bd334d-13ad-8c5c-2122-1afc722fcc9c@dirtcellar.net
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> ---
>  cmds/device.c | 109 +++++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 103 insertions(+), 6 deletions(-)
> 
> diff --git a/cmds/device.c b/cmds/device.c
> index feffe9184726..926fbbd64615 100644
> --- a/cmds/device.c
> +++ b/cmds/device.c
> @@ -27,6 +27,7 @@
>  #include "kerncompat.h"
>  #include "kernel-shared/ctree.h"
>  #include "ioctl.h"
> +#include "common/string-table.h"
>  #include "common/utils.h"
>  #include "kernel-shared/volumes.h"
>  #include "kernel-shared/zoned.h"
> @@ -572,6 +573,7 @@ static const char * const cmd_device_stats_usage[] = {
>  	"",
>  	"-c|--check             return non-zero if any stat counter is not zero",
>  	"-z|--reset             show current stats and reset values to zero",
> +	"-T                     show current stats in tabular format",

We'll need the long option too, but I see it's not in the 'filesystem
usage' either, yet.

>  	HELPINFO_INSERT_GLOBALS,
>  	HELPINFO_INSERT_FORMAT,
>  	NULL
> @@ -642,17 +644,75 @@ static int _print_device_stat_string(struct format_ctx *fctx,
>  	return err;
>  }
> 
> +
> +static int _print_device_stat_tabular(struct string_table *table, int row,

Please don't use the underscored version, that's maybe in some old in
btrfs-progs code but should not be in new.