On Tue, Feb 08, 2022 at 10:36:52AM -0500, Emanuele Giuseppe Esposito wrote: > Doing the opposite can make adding the child node to a non-drained node, > as apply_subtree_drain is only done in ->attach() and thus make > assert_bdrv_graph_writable fail. > > This can happen for example during a transaction rollback (test 245, > test_io_with_graph_changes): > 1. a node is removed from the graph, thus it is undrained > 2. then something happens, and we need to roll back the transactions > through tran_abort() > 3. at this point, the current code would first attach the undrained node > to the graph via QLIST_INSERT_HEAD, and then call ->attach() that > will take care of restoring the drain with apply_subtree_drain(), > leaving the node undrained between the two operations. > > Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com> > --- > block.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-)
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
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