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 <pavel.dovgaluk@ispras.ru>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Pavel Dovgalyuk 2016-03-14 10:44:53 +03:00 committed by Kevin Wolf
parent 6278ae035f
commit c32b82afaf
2 changed files with 14 additions and 0 deletions

View File

@ -2333,6 +2333,13 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
} }
tracked_request_begin(&req, bs, 0, 0, BDRV_TRACKED_FLUSH); 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 */ /* Write back cached data to the OS even with cache=unsafe */
BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS); BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS);
if (bs->drv->bdrv_co_flush_to_os) { if (bs->drv->bdrv_co_flush_to_os) {

View File

@ -175,6 +175,13 @@ struct BlockDriver {
void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp); void (*bdrv_invalidate_cache)(BlockDriverState *bs, Error **errp);
int (*bdrv_inactivate)(BlockDriverState *bs); 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 * Flushes all data that was already written to the OS all the way down to
* the disk (for example raw-posix calls fsync()). * the disk (for example raw-posix calls fsync()).