Re: [PATCH] block: Fix VM size column width in bdrv_snapshot_dump()

[Vladimir Sementsov-Ogievskiy]

02.02.2021 18:59, Kevin Wolf wrote:
> size_to_str() can return a size like "4.24 MiB", with a single digit
> integer part and two fractional digits. This is eight characters, but
> commit b39847a5 changed the format string to only reserve seven
> characters for the column.
>
> This can result in unaligned columns, which in turn changes the output of
> iotests case 267 because exceeding the column size defeats the attempt
> to filter the size out of the output (observed with the ppc64 emulator).
> The resulting change is only a whitespace change, but since commit
> f203080b this is enough for iotests to consider the test failed.
>
> Taking a character away from the tag name column and adding it to the VM
> size column doesn't change anything in the common case (the tag name is
> left justified, the VM size is right justified), but fixes this case.
>
> Fixes: b39847a50553b7679d6d7fefbe6a108a17aacf8d
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

> ---
>   block/qapi.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/block/qapi.c b/block/qapi.c
> index 0a96099e36..84a0aadc09 100644
> --- a/block/qapi.c
> +++ b/block/qapi.c
> @@ -677,7 +677,7 @@ void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
>       char *sizing = NULL;
>   
>       if (!sn) {
> -        qemu_printf("%-10s%-18s%7s%20s%13s%11s",
> +        qemu_printf("%-10s%-17s%8s%20s%13s%11s",

Hmm, the sum is 79, so I think it's safe to keep 18 for tag and still update 7 
to 8.. But it doesn't really matter.

>                       "ID", "TAG", "VM SIZE", "DATE", "VM CLOCK", "ICOUNT");
>       } else {
>           ti = sn->date_sec;
> @@ -696,7 +696,7 @@ void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
>               snprintf(icount_buf, sizeof(icount_buf),
>                   "%"PRId64, sn->icount);
>           }
> -        qemu_printf("%-9s %-17s %7s%20s%13s%11s",
> +        qemu_printf("%-9s %-16s %8s%20s%13s%11s",
>                       sn->id_str, sn->name,
>                       sizing,
>                       date_buf,


--
Best regards,
Vladimir