From 4e4bf5c42c8b2847a90367936a6df6c277f4a76a Mon Sep 17 00:00:00 2001 From: Kevin Wolf Date: Fri, 16 Dec 2016 18:52:37 +0100 Subject: block: Attach bs->file only during .bdrv_open() The way that attaching bs->file worked was a bit unusual in that it was the only child that would be attached to a node which is not opened yet. Because of this, the block layer couldn't know yet which permissions the driver would eventually need. This patch moves the point where bs->file is attached to the beginning of the individual .bdrv_open() implementations, so drivers already know what they are going to do with the child. This is also more consistent with how driver-specific children work. For a moment, bdrv_open() gets its own BdrvChild to perform image probing, but instead of directly assigning this BdrvChild to the BDS, it becomes a temporary one and the node name is passed as an option to the drivers, so that they can simply use bdrv_open_child() to create another reference for their own use. This duplicated child for (the not opened yet) bs is not the final state, a follow-up patch will change the image probing code to use a BlockBackend, which is completely independent of bs. Signed-off-by: Kevin Wolf Reviewed-by: Max Reitz --- block/parallels.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'block/parallels.c') diff --git a/block/parallels.c b/block/parallels.c index ac94dfb497..b2ec09f7e6 100644 --- a/block/parallels.c +++ b/block/parallels.c @@ -581,6 +581,12 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags, Error *local_err = NULL; char *buf; + bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, + false, errp); + if (!bs->file) { + return -EINVAL; + } + ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph)); if (ret < 0) { goto fail; -- cgit v1.2.3