From c32b82afaf261ebb922269e2be298e05331b875c Mon Sep 17 00:00:00 2001 From: Pavel Dovgalyuk Date: Mon, 14 Mar 2016 10:44:53 +0300 Subject: [PATCH] block: add flush callback This patch adds callback for flush request. This callback is responsible for flushing whole block devices stack. bdrv_flush function does not proceed to underlying devices. It should be performed by this callback function, if needed. Signed-off-by: Pavel Dovgalyuk Signed-off-by: Kevin Wolf --- block/io.c | 7 +++++++ include/block/block_int.h | 7 +++++++ 2 files changed, 14 insertions(+) diff --git a/block/io.c b/block/io.c index 4520cab852..c8f5401076 100644 --- a/block/io.c +++ b/block/io.c @@ -2333,6 +2333,13 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs) } tracked_request_begin(&req, bs, 0, 0, BDRV_TRACKED_FLUSH); + + /* Write back all layers by calling one driver function */ + if (bs->drv->bdrv_co_flush) { + ret = bs->drv->bdrv_co_flush(bs); + goto out; + } + /* Write back cached data to the OS even with cache=unsafe */ BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); if (bs->drv->bdrv_co_flush_to_os) { diff --git a/include/block/block_int.h b/include/block/block_int.h index a33b0de40b..1177c25aab 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -175,6 +175,13 @@ struct BlockDriver { void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp); int (*bdrv_inactivate)(BlockDriverState *bs); + /* + * Flushes all data for all layers by calling bdrv_co_flush for underlying + * layers, if needed. This function is needed for deterministic + * synchronization of the flush finishing callback. + */ + int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs); + /* * Flushes all data that was already written to the OS all the way down to * the disk (for example raw-posix calls fsync()).