[libvirt] [PATCHv2 06/15] storage: support more scaling suffixes

[Peter Krempa]

On 03/06/2012 01:34 AM, Eric Blake wrote:
> Disk manufacturers are fond of quoting sizes in powers of 10,
> rather than powers of 2 (after all, 2.1 GB sounds larger than
> 2.0 GiB, even though the exact opposite is true).  So, we might
> as well follow coreutils lead in supporting three types of
> suffix: single letter ${u} (which we already had) and ${u}iB
> for the power of 2, and ${u}B for power of 10.
>
> Additionally, it is impossible to create a file with more than
> 2**63 bytes, since off_t is signed (if you have enough storage
> to even create one 8EiB file, I'm jealous).  This now reports
> failure up front rather than down the road when the kernel
> finally refuses an impossible size.
>
> * docs/schemas/basictypes.rng (unit): Add suffixes.
> * src/conf/storage_conf.c (virStorageSize): Use new function.
> * docs/formatstorage.html.in: Document it.
> ---
>
> v2: new
>
>   docs/formatstorage.html.in                     |   21 +++++---
>   docs/schemas/basictypes.rng                    |    2 +-
>   src/conf/storage_conf.c                        |   61 +++---------------------
>   tests/storagevolxml2xmlin/vol-file-backing.xml |    4 +-
>   tests/storagevolxml2xmlin/vol-file.xml         |    4 +-
>   5 files changed, 26 insertions(+), 66 deletions(-)
>
> diff --git a/docs/formatstorage.html.in b/docs/formatstorage.html.in
> index 93d8ab2..b0acaf3 100644
> --- a/docs/formatstorage.html.in
> +++ b/docs/formatstorage.html.in
> @@ -236,13 +236,20 @@
>           <br/>
>           By default this is specified in bytes, but an optional
>           <code>unit</code>  can be specified to adjust the passed value.
> -        Values can be: 'K' (kibibytes, 2<sup>10</sup>  or 1024), 'M'
> -        (mebibytes, 2<sup>20</sup>  or 1,048,576), 'G' (gibibytes,
> -        2<sup>30</sup>  or 1,073,741,824), 'T' (tebibytes,
> -        2<sup>40</sup>  or 1,099,511,627,776), 'P' (pebibytes,
> -        2<sup>50</sup>  or 1,125,899,906,842,624), or 'E' (exbibytes,
> -        2<sup>60</sup>  or 1,152,921,504,606,846,976).
> -<span class="since">Since 0.4.1</span></dd>
> +        Values can be: 'B' or 'bytes' for bytes, 'KB' (kilobytes,
> +        10<sup>3</sup>  or 1000), 'K' or 'KiB' (kibibytes,
> +        2<sup>10</sup>  or 1024), 'MB' (megabytes, 10<sup>6</sup>  or
> +        1,000,000), 'M' or 'MiB' (mebibytes, 2<sup>20</sup>  or
> +        1,048,576), 'GB' (gigabytes, 10<sup>9</sup>  or 1,000,000,000),
> +        'G' or 'GiB' (gibibytes, 2<sup>30</sup>  or 1,073,741,824),

As Christophe pointed out on 01/15, it would probably be better to state 
that the numbers are in bytes.

> +        'TB' (terabytes, 10<sup>12</sup>  or 1,000,000,000,000), 'T' or
> +        'TiB' (tebibytes, 2<sup>40</sup>  or 1,099,511,627,776), 'PB'
> +        (petabytes, 10<sup>15</sup>  or 1,000,000,000,000,000), 'P' or
> +        'PiB' (pebibytes, 2<sup>50</sup>  or 1,125,899,906,842,624),
> +        'EB' (exabytes, 10<sup>18</sup>  or 1,000,000,000,000,000,000),
> +        or 'E' or 'EiB' (exbibytes, 2<sup>60</sup>  or
> +        1,152,921,504,606,846,976).<span class="since">Since 0.4.1,
> +        multi-character<code>unit</code>  since 0.9.11</span></dd>
>         <dt><code>capacity</code></dt>
>         <dd>Providing the logical capacity for the volume. This value is
>           in bytes by default, but a<code>unit</code>  attribute can be
> diff --git a/docs/schemas/basictypes.rng b/docs/schemas/basictypes.rng
> index a50349c..cc0bc12 100644
> --- a/docs/schemas/basictypes.rng
> +++ b/docs/schemas/basictypes.rng
> @@ -140,7 +140,7 @@
>
>     <define name='unit'>
>       <data type='string'>
> -<param name='pattern'>(bytes)|[kKmMgGtTpPeE]</param>
> +<param name='pattern'>([bB]([yY][tT][eE][sS]?)?)|([kKmMgGtTpPeE]([iI]?[bB])?)</param>

This makes the comment from the last patch obsolete.

>       </data>
>     </define>
>     <define name='scaledInteger'>


ACK,

Peter