Re: [Qemu-devel] [PATCH] use int64_t for return values from rbd instead of int

[Stefan Priebe]

Hi Stefan,

Am 20.11.2012 17:29, schrieb Stefan Hajnoczi:
> On Tue, Nov 20, 2012 at 01:44:55PM +0100, Stefan Priebe wrote:
> > rbd / rados tends to return pretty often length of writes
> > or discarded blocks. These values might be bigger than int.
> >
> > Signed-off-by: Stefan Priebe <address@hidden>
> > ---
> >   block/rbd.c |    4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
>
> Looks good but I want to check whether this fixes an bug you've hit?
> Please indicate details of the bug and how to reproduce it in the commit
> message.

you get various I/O errors in client. As negative return values indicate 
I/O errors. When now a big positive value is returned by librbd 
block/rbd tries to store this one in acb->ret which is an int. Then it 
wraps around and is negative. After that block/rbd thinks this is an I/O 
error and report this to the guest.

Stefan