Re: [Qemu-devel] [PATCH] overflow of int ret: use ssize_t for ret

[Andreas Färber]

Am 22.11.2012 10:07, schrieb Stefan Priebe:
> When acb->cmd is WRITE or DISCARD block/rbd stores rcb->size into acb->ret
> 
> Look here:
>    if (acb->cmd == RBD_AIO_WRITE ||
>         acb->cmd == RBD_AIO_DISCARD) {
>         if (r < 0) {
>             acb->ret = r;
>             acb->error = 1;
>         } else if (!acb->error) {
>             acb->ret = rcb->size;
>         }
> 
> right now acb->ret is just an int and we might get an overflow if size is too 
> big.
> For discards rcb->size holds the size of the discard - this might be some TB 
> if you
> discard a whole device.
> 
> The steps to reproduce are:
> mkfs.xfs -f a whole device bigger than int in bytes. mkfs.xfs sends a 
> discard. Important is that you use scsi-hd and set discard_granularity=512. 
> Otherwise rbd disabled discard support.

Whatever type you decide to use, please add an identifying topic such as
"block/rbd:" in the subject (int ret is very generic!), and this patch
is missing a Signed-off-by.

Regards,
Andreas


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