block: Fix bdrv_co_flush early return

bdrv_inc_in_flight and bdrv_dec_in_flight are mandatory for
BDRV_POLL_WHILE to work, even for the shortcut case where flush is
unnecessary. Move the if block to below bdrv_dec_in_flight, and BTW fix
the variable declaration position.

Signed-off-by: Fam Zheng <famz@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Fam Zheng 2017-04-10 21:00:50 +08:00
parent e92f0e1910
commit 49ca625913

View file

@ -2278,16 +2278,17 @@ static void coroutine_fn bdrv_flush_co_entry(void *opaque)
int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
{
int ret;
if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) ||
bdrv_is_sg(bs)) {
return 0;
}
int current_gen;
int ret = 0;
bdrv_inc_in_flight(bs);
int current_gen = bs->write_gen;
if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) ||
bdrv_is_sg(bs)) {
goto early_exit;
}
current_gen = bs->write_gen;
/* Wait until any previous flushes are completed */
while (bs->active_flush_req) {
@ -2370,6 +2371,7 @@ out:
/* Return value is ignored - it's ok if wait queue is empty */
qemu_co_queue_next(&bs->flush_queue);
early_exit:
bdrv_dec_in_flight(bs);
return ret;
}