Re: [Qemu-devel] [PATCHv2] block: add native support for NFS

[Peter Lieven]

> Am 17.12.2013 um 18:28 schrieb ronnie sahlberg <address@hidden>:
> 
>> On Tue, Dec 17, 2013 at 9:03 AM, Peter Lieven <address@hidden> wrote:
>>> On 17.12.2013 17:47, Stefan Hajnoczi wrote:
>>> 
>>> On Tue, Dec 17, 2013 at 10:15:25AM +0100, Peter Lieven wrote:
> 
> ...
>>>> +    if (nfs_pwrite_async(client->context, client->fh,
>>>> +                         sector_num * BDRV_SECTOR_SIZE,
>>>> +                         nb_sectors * BDRV_SECTOR_SIZE,
>>>> +                         buf, nfs_co_generic_cb, &task) != 0) {
>>>> +        g_free(buf);
>>>> +        return -EIO;
>>> 
>>> Can we get a more detailed errno here?  (e.g. ENOSPC)
>> 
>> libnfs only returns 0 or -1 if the setup of the call
>> fails. the status code from the RPC is more detailed
>> and available in task.status.
> 
> The *_async() functions only allocates memory and marshalls the
> arguments to the buffer.
> So barring marshalling bugs, it will only fail due to OOM.
> 
> So -ENOMEM is perhaps a better error for when *_async() returns an error.
> That is really the only condition where these functions will fail.

i guess the same applies to libiscsi?!
i will change it in v3 and make a patch for the iscsi driver.

> 
> 
> If *_async() returns success you are guaranteed that
> nfs_co_generic_cb() will be invoked
> and there you can inspect the status argument for more detailed reason why.