diff --git a/block/io.c b/block/io.c index 7100344c7b..914ba78f1a 100644 --- a/block/io.c +++ b/block/io.c @@ -288,6 +288,18 @@ static void bdrv_co_drain_bh_cb(void *opaque) BlockDriverState *bs = data->bs; if (bs) { + AioContext *ctx = bdrv_get_aio_context(bs); + AioContext *co_ctx = qemu_coroutine_get_aio_context(co); + + /* + * When the coroutine yielded, the lock for its home context was + * released, so we need to re-acquire it here. If it explicitly + * acquired a different context, the lock is still held and we don't + * want to lock it a second time (or AIO_WAIT_WHILE() would hang). + */ + if (ctx == co_ctx) { + aio_context_acquire(ctx); + } bdrv_dec_in_flight(bs); if (data->begin) { bdrv_do_drained_begin(bs, data->recursive, data->parent, @@ -296,6 +308,9 @@ static void bdrv_co_drain_bh_cb(void *opaque) bdrv_do_drained_end(bs, data->recursive, data->parent, data->ignore_bds_parents); } + if (ctx == co_ctx) { + aio_context_release(ctx); + } } else { assert(data->begin); bdrv_drain_all_begin(); diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h index 6f8a487041..9801e7f5a4 100644 --- a/include/qemu/coroutine.h +++ b/include/qemu/coroutine.h @@ -89,6 +89,11 @@ void qemu_aio_coroutine_enter(AioContext *ctx, Coroutine *co); */ void coroutine_fn qemu_coroutine_yield(void); +/** + * Get the AioContext of the given coroutine + */ +AioContext *coroutine_fn qemu_coroutine_get_aio_context(Coroutine *co); + /** * Get the currently executing coroutine */ diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c index 1ba4191b84..2295928d33 100644 --- a/util/qemu-coroutine.c +++ b/util/qemu-coroutine.c @@ -198,3 +198,8 @@ bool qemu_coroutine_entered(Coroutine *co) { return co->caller; } + +AioContext *coroutine_fn qemu_coroutine_get_aio_context(Coroutine *co) +{ + return co->ctx; +}