From 3f5075ae63b6dc1de9428d028a4d28fc98e7fdff Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 12 Jan 2010 13:49:23 +0100 Subject: [PATCH] block: flush backing_hd in the right place The backing device is only modified from bdrv_commit. So instead of flushing it every time bdrv_flush is called for the front-end device only flush it after we're written data to it in bdrv_commit. Signed-off-by: Christoph Hellwig Signed-off-by: Anthony Liguori --- block.c | 17 +++++++---------- 1 file changed, 7 insertions(+), 10 deletions(-) diff --git a/block.c b/block.c index c7bc83773a..115e5913eb 100644 --- a/block.c +++ b/block.c @@ -594,6 +594,12 @@ int bdrv_commit(BlockDriverState *bs) if (drv->bdrv_make_empty) return drv->bdrv_make_empty(bs); + /* + * Make sure all data we wrote to the backing device is actually + * stable on disk. + */ + if (bs->backing_hd) + bdrv_flush(bs->backing_hd); return 0; } @@ -1115,12 +1121,8 @@ const char *bdrv_get_device_name(BlockDriverState *bs) void bdrv_flush(BlockDriverState *bs) { - if (!bs->drv) - return; - if (bs->drv->bdrv_flush) + if (bs->drv && bs->drv->bdrv_flush) bs->drv->bdrv_flush(bs); - if (bs->backing_hd) - bdrv_flush(bs->backing_hd); } void bdrv_flush_all(void) @@ -1797,11 +1799,6 @@ BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs, if (!drv) return NULL; - - /* - * Note that unlike bdrv_flush the driver is reponsible for flushing a - * backing image if it exists. - */ return drv->bdrv_aio_flush(bs, cb, opaque); }