Re: [Qemu-devel] [PATCH 3/4] qemu-nbd: add doc for internal snapshot export

[Wenchao Xia]

于 2013-7-26 16:11, Stefan Hajnoczi 写道:
> On Wed, Jul 17, 2013 at 10:03:54PM +0800, Wenchao Xia wrote:
>> Signed-off-by: Wenchao Xia <xiaw...@linux.vnet.ibm.com>
>> ---
>>   qemu-nbd.c    |    2 ++
>>   qemu-nbd.texi |    3 +++
>>   2 files changed, 5 insertions(+), 0 deletions(-)
>>
>> diff --git a/qemu-nbd.c b/qemu-nbd.c
>> index 46be2b2..8eeee33 100644
>> --- a/qemu-nbd.c
>> +++ b/qemu-nbd.c
>> @@ -80,6 +80,8 @@ static void usage(const char *name)
>>   "Block device options:\n"
>>   "  -r, --read-only      export read-only\n"
>>   "  -s, --snapshot       use snapshot file\n"
>> +"  -l, --snapshot-load  temporarily load an internal snapshot and export it 
>> as\n"
>> +"                       an read-only device, format is 
>> 'id=[ID],name=[NAME]'\n"
> 
> Does it really export it read-only?  I think you'll get an error unless
> you pass qemu-nbd --read-only.
> 
  I think so. In patch 2:

+        case 'l':
+            sn_param = parse_option_parameters(optarg,
+                                               snapshot_options, sn_param);
+            if (!sn_param) {
+                errx(EXIT_FAILURE,
+                     "Invalid snapshot-load options '%s'", optarg);
+            }
         case 'r':
             nbdflags |= NBD_FLAG_READ_ONLY;
             flags &= ~BDRV_O_RDWR;

  when "l" is set, readonly will also be set.

-- 
Best Regards

Wenchao Xia