Currently, if the user requests aio=native, but forgets to choose a cache mode that sets O_DIRECT, that request is silently ignored and raw falls back to aio=threads.
Deprecate that behaviour so we can make it an error in future qemu versions. Signed-off-by: Kevin Wolf <kw...@redhat.com> Reviewed-by: Markus Armbruster <arm...@redhat.com> --- block/raw-posix.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/block/raw-posix.c b/block/raw-posix.c index 844ac21..24d8582 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -503,6 +503,14 @@ static int raw_open_common(BlockDriverState *bs, QDict *options, error_setg_errno(errp, -ret, "Could not set AIO state"); goto fail; } + if (!s->use_aio && (bdrv_flags & BDRV_O_NATIVE_AIO)) { + error_printf("WARNING: aio=native was specified for '%s', but " + "it requires cache.direct=on, which was not " + "specified. Falling back to aio=threads.\n" + " This will become an error condition in " + "future QEMU versions.\n", + bs->filename); + } #endif s->has_discard = true; -- 1.8.3.1