The fiction -- and ONLY the fiction -- kicks off the moves.
The ogre brings its club down on the fighter. I ask, "What do you do?"
The thing the player of the Fighter says next determines what move (if any) he will make. There is no "rule" that says he must Defy Danger now. Or must Hack and Slash. There are no rules at all about how moves occur and snowball except, "when you do it, you roll it."
I'm seeing a lot of systematic thinking going on here, with sweeping generalizations. "If the Fighter always has to roll Defy Danger and Hack and Slash, then blah blah blah." No. There is no "always." There is no "combat system" that you employ over and over again. Each moment is unique and must be examined (possibly in fine detail) fictionally in order to determine the moves that are rolled.
Here are some examples of how this moment might play out. Notice how the fiction (especially the group's unique local understanding of the qualities of their dungeon world) is critical to determining the moves in play.
-------------
Defy Danger + Roll Damage
"The ogre's massive club -- actually an uprooted oak tree -- comes crashing down at your head. What do you do?"
"I turn it aside with my shield, and drive my spear up into the monster's throat."
"Really? You turn aside a tree with your shield? It's like you're being hit by a car."
"Oh! It's like that? Wow, okay, I guess ogres are crazy strong. I wasn't thinking of it like that. No, I can't use my shield against a car crash. I guess I better get out of the way, then. Defy danger?"
"Yeah, that sounds right. How do you do that?"
"I roll to the side, sliding on my shield a bit, keeping my spear pointed right at the ogre."
(rolls, gets a 10+)
"The ogre's club crashes down, but you roll aside. The stone floor tiles shatter under the impact, and the club sinks a few inches into the soft earth beneath. The ogre roars."
"Ha! Too slow, sucker! I drive the spear right into his face. Is that hack and slash?"
"Nope. The ogre's weapon isn't ready, and you're out of reach since you're using your spear. It's not a melee. You just stab him. Roll your damage!"
--------------
Hack and Slash
"The ogre's massive club -- actually an uprooted oak tree -- comes crashing down at your head. What do you do?"
"I turn it aside with my shield, and drive my spear up into the monster's throat."
"Really? You turn aside a tree with your shield? It's like you're being hit by a car."
"Wait, but I'm like, a fantasy hero, right? Can't we do stuff like that?"
"Hmmm. I guess we should decide that. You guys think the PCs should be more epic? Yeah? Okay, that works for me. You can totally turn aside a crashing tree trunk with your shield. That's pretty badass."
"Yeah, awesome! So, I'm blocking and counter-attacking here... that's hack and slash. It's a melee."
"Yep, definitely. Roll it."
---------------
Defy Danger + Hack and Slash
"The ogre's massive club -- actually an uprooted oak tree -- comes crashing down at your head. What do you do?"
"Uh. A tree trunk? Shit. I jump out of the way! That's defy danger... right? Damn, an 8."
"The tree narrowly misses your head as you jump aside, but it hits your spear, shattering it to splinters. What do you do?"
"Crap! Well, I still have my shield, and it's got a wicked spike on it, remember? I roll, leap up, and smash the spike into the ogre's knee!"
"Oooh, ouch. That'll hurt. The ogre's club isn't ready to swing again, so he lets it go and reaches out to catch the shield before the spike impales him. It's a melee. Roll hack and slash."
"Can't I get in there before he can react?"
"Hmmm. If he was trying to swing the club again, yeah, definitely. But he's dropping the club and going straight to wrestling, so I think it's a melee."
"Okay, yeah, I can see that."
----------------
I could go on. Like Sage said, there are an infinite number of ways that could go down, depending greatly on the fictional situation. And I haven't even included terrain issues (a tight tunnel vs. open chamber changes things dramatically) or the presence of other monsters/hazards, or lighting conditions (sometimes you have to drop your torch to fight), etc. etc.
In your game, maybe ogres aren't so scary-strong, and their clubs are just regular clubs. That changes everything! The fiction comes first, and the moves must always flow from it.
The amount of fictional stuff you account for is something that the group will fine-tune as play goes along. But if the amount is "barely any" then you'll find the game starts to fight you, and doesn't entirely work right, which I think you're starting to see.