From f8aa905a4fec89863c82de4186352447d851871e Mon Sep 17 00:00:00 2001 From: Jeff Cody Date: Mon, 1 Feb 2016 20:33:10 -0500 Subject: block: set device_list.tqe_prev to NULL on BDS removal This fixes a regression introduced with commit 3f09bfbc7. Multiple bugs arise in conjunction with live snapshots and mirroring operations (which include active layer commit). After a live snapshot occurs, the active layer and the base layer both have a non-NULL tqe_prev field in the device_list, although the base node's tqe_prev field points to a NULL entry. This non-NULL tqe_prev field occurs after the bdrv_append() in the external snapshot calls change_parent_backing_link(). In change_parent_backing_link(), when the previous active layer is removed from device_list, the device_list.tqe_prev pointer is not set to NULL. The operating scheme in the block layer is to indicate that a BDS belongs in the bdrv_states device_list iff the device_list.tqe_prev pointer is non-NULL. This patch does two things: 1.) Introduces a new block layer helper bdrv_device_remove() to remove a BDS from the device_list, and 2.) uses that new API, which also fixes the regression once used in change_parent_backing_link(). Signed-off-by: Jeff Cody Message-id: 0cd51e11c0666c04ddb7c05293fe94afeb551e89.1454376655.git.jcody@redhat.com Reviewed-by: Max Reitz Signed-off-by: Max Reitz --- blockdev.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'blockdev.c') diff --git a/blockdev.c b/blockdev.c index 35e1e5c58f..be4ca44ab2 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2408,8 +2408,7 @@ void qmp_x_blockdev_remove_medium(const char *device, Error **errp) /* This follows the convention established by bdrv_make_anon() */ if (bs->device_list.tqe_prev) { - QTAILQ_REMOVE(&bdrv_states, bs, device_list); - bs->device_list.tqe_prev = NULL; + bdrv_device_remove(bs); } blk_remove_bs(blk); -- cgit v1.2.1