Re: [Qemu-devel] [PATCH V9 3/4] raw-posix: Add full image preallocation option

[Markus Armbruster]

Peter Lieven <address@hidden> writes:

> Am 27.05.2014 um 21:24 schrieb Eric Blake <address@hidden>:
>
>> On 05/27/2014 02:22 AM, Chen Fan wrote:
>>> From: Hu Tao <address@hidden>
>>> 
>>> This patch adds a new option preallocation for raw format, and implements
>>> full preallocation by writing zeros to disk.
>>> 
>>> The metadata option is changed to use posix_fallocate() to ensure
>>> subsquent writes to image file won't fail because of lack of disk space.
>>> 
>>> The purpose is to ensure disk space for image file. In cases
>>> posix_fallocate() is supported, metadata option can be used, otherwise
>>> (posix_fallocate() is not supported by filesystem, or in case of thin
>>> provisioning), full option has to be used. User has to choose the proper
>>> way to use.
>>> 
>>> Signed-off-by: Hu Tao <address@hidden>
>>> ---
>>> block/raw-posix.c | 61
>>> ++++++++++++++++++++++++++++++++++++++++++++++++-------
>>> 1 file changed, 54 insertions(+), 7 deletions(-)
>>> 
>> 
>>> @@ -1254,6 +1255,18 @@ static int raw_create(const char *filename, 
>>> QEMUOptionParameter *options,
>>>         if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
>>>             total_size = (options->value.n + BDRV_SECTOR_SIZE) &
>>>                 BDRV_SECTOR_MASK;
>>> +        } else if (!strcmp(options->name, BLOCK_OPT_PREALLOC)) {
>>> +            if (!options->value.s || !strcmp(options->value.s, "off")) {
>>> +                prealloc = PREALLOC_MODE_OFF;
>>> +            } else if (!strcmp(options->value.s, "metadata")) {
>>> +                prealloc = PREALLOC_MODE_METADATA;
>>> +            } else if (!strcmp(options->value.s, "full")) {
>>> +                prealloc = PREALLOC_MODE_FULL;
>>> +            } else {
>> 
>> Instead of open-coding this conversion from string to enum, can you
>> reuse Peter's pending patch?  (Hmm, that means Peter needs to export it
>> to somewhere public, not just blockdev.c)
>> 
>> https://lists.gnu.org/archive/html/qemu-devel/2014-05/msg03772.html
>
> I don't mind if this function is made public. You can send a patch for it.
> Please don't forget to remove the static declaration. You might
> also want to remove the inline. This was just to avoid an unused
> function error. I don't know if blockdev.c is still the right
> place for this function then.

Probably not.  I'd rename to qapi_enum_parse(), and move it to qapi/.
If no existing file fits, create a new one, say qapi/qapi-util.c.