Anthony Liguori schrieb:
> Kevin Wolf wrote:
>> Anthony Liguori schrieb:
>>
>> Yes, if it fails, the EINVAL is no surprise. I meant what code path it
>> was using. Obviously we missed something in our patch and I'd like to
>> fix that. Did the error occur on raw images or something like qcow2?
>>
>
> It's a raw image and the calls are being made via
> bdrv_aio_read/bdrv_aio_write. It doesn't occur with a qcow2 but then
> cache=off doesn't seem to do what it's supposed to with cache=off (I
> believe the underlying backing file is not opened O_DIRECT?).
This is really strange. In raw_aio_read/write there is a check like this:
if (unlikely(s->aligned_buf != NULL && ((uintptr_t) buf % 512))) {
// emulate it using raw_pread/write which uses
// s->aligned_buf for the request then
}
For qcow2 I think O_DIRECT actually is in effect. Otherwise it would
have worked even without our patch, and it didn't. And indeed, looking
at the code, it passes flags to bdrv_file_open when it opens the image file.
Kevin
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