Re: Question about loop device DIO/AIO and FLUSH

On Fri, Jul 1, 2016 at 4:54 AM, Amir Goldstein [off-list ref] wrote:

Hi Ming,

I was reading through the code of loop DIO/AIO
and I was wondering whether lo_req_flush() really
honors REQ_FLUSH by calling  vfs_fsync() on a backing file
that is open with O_DIRECT?

From view of device, REQ_FLUSH just flushs the cache inside

drive to medium.

Shouldn't lo_req_flush() actually wait for completion of
all the in-flight loop AIO requests to complete?

I think it isn't needed, just like the flush handling in blk-flush.c, and
it just works for completed I/O.

Am I missing something?

Thanks,
Amir.
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