block: Convert bdrv_co_preadv/pwritev to BdrvChild

This is the final patch for converting the common I/O path to take
a BdrvChild parameter instead of BlockDriverState.

The completion of this conversion means that all users that perform I/O
on an image need to actually hold a reference (in the form of BdrvChild,
possible as part of a BlockBackend) to that image. This also protects
against inconsistent use of BlockBackend vs. BlockDriverState functions
because direct use of a BlockDriverState isn't possible any more and
blk->root is private for block-backends.c.

In addition, we can now distinguish different users in the I/O path,
and the future op blockers work is going to add assertions based on
permissions stored in BdrvChild.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Kevin Wolf 2016-06-20 21:31:46 +02:00
parent e293b7a3df
commit a03ef88f77
12 changed files with 38 additions and 37 deletions

View file

@ -446,7 +446,7 @@ static int coroutine_fn do_perform_cow(BlockDriverState *bs,
}
BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE);
ret = bdrv_co_pwritev(bs->file->bs, cluster_offset + offset_in_cluster,
ret = bdrv_co_pwritev(bs->file, cluster_offset + offset_in_cluster,
bytes, &qiov, 0);
if (ret < 0) {
goto out;