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From: Markus Armbruster <armbru@redhat.com>
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Date: Fri, 03 Mar 2017 15:57:02 +0100
In-Reply-To: <20170303134930.GE14351@noname.redhat.com> (Kevin Wolf's message
	of "Fri, 3 Mar 2017 14:49:30 +0100")
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Subject: Re: [Qemu-devel] [PATCH 07/15] sheepdog: Report errors in
 pseudo-filename more usefully
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To: Kevin Wolf <kwolf@redhat.com>
Cc: mitake.hitoshi@lab.ntt.co.jp, namei.unix@gmail.com, jcody@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org

Kevin Wolf <kwolf@redhat.com> writes:

> Am 02.03.2017 um 22:43 hat Markus Armbruster geschrieben:
>> Errors in the pseudo-filename are all reported with the same laconic
>> "Can't parse filename" message.
>> 
>> Add real error reporting, such as:
>> 
>>     $ qemu-system-x86_64 --drive driver=sheepdog,filename=sheepdog:///
>>     qemu-system-x86_64: --drive driver=sheepdog,filename=sheepdog:///: missing file path in URI
>>     $ qemu-system-x86_64 --drive driver=sheepdog,filename=sheepgod:///vdi
>>     qemu-system-x86_64: --drive driver=sheepdog,filename=sheepgod:///vdi: URI scheme must be 'sheepdog', 'sheepdog+tcp', or 'sheepdog+unix'
>>     $ qemu-system-x86_64 --drive driver=sheepdog,filename=sheepdog+unix:///vdi?socke=sheepdog.sock
>>     qemu-system-x86_64: --drive driver=sheepdog,filename=sheepdog+unix:///vdi?socke=sheepdog.sock: unexpected query parameters
>> 
>> The code to translate legacy syntax to URI fails to escape URI
>> meta-characters.  The new error messages are misleading then.  Replace
>> them by the old "Can't parse filename" message.  "Internal error"
>> would be more honest.  Anyway, no worse than before.  Also add a FIXME
>> comment.
>> 
>> Signed-off-by: Markus Armbruster <armbru@redhat.com>
>
>> @@ -1451,12 +1480,12 @@ static int sd_open(BlockDriverState *bs, QDict *options, int flags,
>>      memset(tag, 0, sizeof(tag));
>>  
>>      if (strstr(filename, "://")) {
>> -        ret = sd_parse_uri(s, filename, vdi, &snapid, tag);
>> +        sd_parse_uri(s, filename, vdi, &snapid, tag, &local_err);
>>      } else {
>> -        ret = parse_vdiname(s, filename, vdi, &snapid, tag);
>> +        parse_vdiname(s, filename, vdi, &snapid, tag, &local_err);
>>      }
>> -    if (ret < 0) {
>> -        error_setg(errp, "Can't parse filename");
>> +    if (local_err) {
>> +        error_propagate(errp, local_err);
>>          goto out_no_fd;
>>      }
>
> I have to take my R-b back, ret isn't set here any more:
>
> block/sheepdog.c: In function 'sd_open':
> block/sheepdog.c:1451:9: error: 'ret' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>      int ret, fd;

Healed in PATCH 09, but of course I'll fix it anyway.