On 17.12.19 15:59, Kevin Wolf wrote: > bdrv_invalidate_cache_all() assumes that all nodes in a given subtree > are either active or inactive when it starts. Therefore, as soon as it > arrives at an already active node, it stops. > > However, this assumption is wrong. For example, it's possible to take a > snapshot of an inactive node, which results in an active overlay over an > inactive backing file. The active overlay is probably also the root node > of an inactive BlockBackend (blk->disable_perm == true). > > In this case, bdrv_invalidate_cache_all() does not need to do anything > to activate the overlay node, but it still needs to recurse into the > children and the parents to make sure that after returning success, > really everything is activated. > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > --- > block.c | 50 ++++++++++++++++++++++++-------------------------- > 1 file changed, 24 insertions(+), 26 deletions(-)
Basically the only change is to not skip the whole function when the node is already active but only the part that actually activates the node. blk_root_activate() is a no-op for already-active BBs, so this looks good to me. Reviewed-by: Max Reitz <mre...@redhat.com>
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