23.11.2020 23:12, Vladimir Sementsov-Ogievskiy wrote:
Add additional check that node parents do not interfere with each other. This should not hurt existing callers and allows in further patch use bdrv_refresh_perms() to update a subtree of changed BdrvChild (check that change is correct).New check will substitute bdrv_check_update_perm() in following permissions refactoring, so keep error messages the same to avoid unit test result changes. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> --- block.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 53 insertions(+), 9 deletions(-) diff --git a/block.c b/block.c index 0dd28f0902..0d0f065db4 100644 --- a/block.c +++ b/block.c @@ -1945,6 +1945,56 @@ bool bdrv_is_writable(BlockDriverState *bs) return bdrv_is_writable_after_reopen(bs, NULL); }+static char *bdrv_child_user_desc(BdrvChild *c)+{ + if (c->klass->get_parent_desc) { + return c->klass->get_parent_desc(c); + } + + return g_strdup("another user"); +} + +static bool bdrv_a_allow_b(BdrvChild *a, BdrvChild *b, Error **errp) +{ + g_autofree char *user = NULL; + g_autofree char *perm_names = NULL; + + if ((b->perm & a->shared_perm) == b->perm) { + return true; + } + + perm_names = bdrv_perm_names(b->perm & ~a->shared_perm); + user = bdrv_child_user_desc(a); + error_setg(errp, "Conflicts with use by %s as '%s', which does not " + "allow '%s' on %s", + user, a->name, perm_names, bdrv_get_node_name(b->bs)); + + return false; +} + +static bool bdrv_check_parents_compliance(BlockDriverState *bs, Error **errp) +{ + BdrvChild *a, *b; + + QLIST_FOREACH(a, &bs->parents, next_parent) { + QLIST_FOREACH(b, &bs->parents, next_parent) { + if (a == b) { + continue; + } + + if (!bdrv_a_allow_b(a, b, errp)) { + return false; + } + + if (!bdrv_a_allow_b(b, a, errp)) { + return false; + }
drop this if. We look at each pair twice anyway. -- Best regards, Vladimir
