diff options
| -rw-r--r-- | block.c | 36 | ||||
| -rw-r--r-- | include/block/block.h | 1 |
2 files changed, 30 insertions, 7 deletions
@@ -1904,6 +1904,34 @@ static bool bdrv_requests_pending(BlockDriverState *bs) return false; } +static bool bdrv_drain_one(BlockDriverState *bs) +{ + bool bs_busy; + + bdrv_flush_io_queue(bs); + bdrv_start_throttled_reqs(bs); + bs_busy = bdrv_requests_pending(bs); + bs_busy |= aio_poll(bdrv_get_aio_context(bs), bs_busy); + return bs_busy; +} + +/* + * Wait for pending requests to complete on a single BlockDriverState subtree + * + * See the warning in bdrv_drain_all(). This function can only be called if + * you are sure nothing can generate I/O because you have op blockers + * installed. + * + * Note that unlike bdrv_drain_all(), the caller must hold the BlockDriverState + * AioContext. + */ +void bdrv_drain(BlockDriverState *bs) +{ + while (bdrv_drain_one(bs)) { + /* Keep iterating */ + } +} + /* * Wait for pending requests to complete across all BlockDriverStates * @@ -1927,16 +1955,10 @@ void bdrv_drain_all(void) QTAILQ_FOREACH(bs, &bdrv_states, device_list) { AioContext *aio_context = bdrv_get_aio_context(bs); - bool bs_busy; aio_context_acquire(aio_context); - bdrv_flush_io_queue(bs); - bdrv_start_throttled_reqs(bs); - bs_busy = bdrv_requests_pending(bs); - bs_busy |= aio_poll(aio_context, bs_busy); + busy |= bdrv_drain_one(bs); aio_context_release(aio_context); - - busy |= bs_busy; } } } diff --git a/include/block/block.h b/include/block/block.h index 5d13282..13e4537 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -334,6 +334,7 @@ int bdrv_flush(BlockDriverState *bs); int coroutine_fn bdrv_co_flush(BlockDriverState *bs); int bdrv_flush_all(void); void bdrv_close_all(void); +void bdrv_drain(BlockDriverState *bs); void bdrv_drain_all(void); int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors); |