Re: [Qemu-devel] [PATCH v3 4/5] block: Convert open calls to qemu_open

[Corey Bryant <coreyb@linux.vnet.ibm.com>]

On 06/15/2012 11:21 AM, Eric Blake wrote:
> On 06/14/2012 09:55 AM, Corey Bryant wrote:
>> This patch converts all block layer open calls to qemu_open.  This
>> enables all block layer open paths to dup(X) a pre-opened file
>> descriptor if the filename is of the format /dev/fd/X.  This is
>> useful if QEMU is restricted from opening certain files.
>>
>> Note that this adds the O_CLOEXEC flag to the changed open paths
>> when the O_CLOEXEC macro is defined.
>>
>
>> @@ -741,7 +741,7 @@ static int hdev_open(BlockDriverState *bs, const char *filename, int flags)
>>           if ( bsdPath[ 0 ] != '\0' ) {
>>               strcat(bsdPath,"s0");
>>               /* some CDs don't have a partition 0 */
>> -            fd = open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE);
>> +            fd = qemu_open(bsdPath, O_RDONLY | O_BINARY | O_LARGEFILE);
>
> Why are we even bothering with O_LARGEFILE?  Shouldn't we be compiling
> with large file support always enabled, so that we are always calling
> open64 in the cases where it matters, without having to explicitly add
> the O_LARGEFILE flag ourselves?
>

That might be a no-op too since large file support looks to already be 
set at compile time:

257 QEMU_CFLAGS="-D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 
-D_LARGEFILE_SOURCE $QEMU_CFLAGS"

>
>> +++ b/block/vdi.c
>> @@ -648,8 +648,9 @@ static int vdi_create(const char *filename, QEMUOptionParameter *options)
>>           options++;
>>       }
>>
>> -    fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
>> -              0644);
>> +    fd = qemu_open(filename,
>> +                   O_WRONLY | O_CREAT | O_TRUNC | O_BINARY | O_LARGEFILE,
>
> More instances.  In fact, scrubbing O_LARGEFILE, is probably worth a
> separate patch.
>

I'm happy to do it.  Kevin or anyone else want to weigh in first?

-- 
Regards,
Corey