QEMU silently ignores aio=native if libaio is unavailable. It is
confusing when aio=native performance is identical to aio=threads
because the binary was accidentally built without libaio.
Use error_report() because failing would break backward compatibility.
There are probably users using aio=native who would be inconvenienced if
QEMU suddenly refused to start their guests.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
blockdev.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/blockdev.c b/blockdev.c
index 62a4586..f30828a 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -405,10 +405,14 @@ static BlockBackend *blockdev_init(const char *file,
QDict *bs_opts,
bdrv_flags |= BDRV_O_NO_FLUSH;
}
-#ifdef CONFIG_LINUX_AIO
if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
if (!strcmp(buf, "native")) {
+#ifdef CONFIG_LINUX_AIO
bdrv_flags |= BDRV_O_NATIVE_AIO;
+#else
+ error_report("warning: aio=native support unavailable, "
+ "using default instead");
+#endif
} else if (!strcmp(buf, "threads")) {
/* this is the default */
} else {
@@ -416,7 +420,6 @@ static BlockBackend *blockdev_init(const char *file, QDict
*bs_opts,
goto early_err;
}
}
-#endif
if ((buf = qemu_opt_get(opts, "format")) != NULL) {
if (is_help_option(buf)) {
--
2.4.3
