bcachefs: Extents may now cross btree node boundaries

When snapshots arrive, we won't necessarily be able to arbitrarily split
existis - when we need to split an existing extent, we'll have to check
if the extent was overwritten in child snapshots and if so emit a
whiteout for the split in the child snapshot.

Because extents couldn't span btree nodes previously, journal replay
would sometimes have to split existing extents. That's no good anymore,
but fortunately since extent handling has already been lifted above most
of the btree code there's no real need for that rule anymore.

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 8 insertions, 21 deletions

diff --git a/fs/bcachefs/extent_update.c b/fs/bcachefs/extent_update.c
index 5c43678e94a3..16d2bca8a662 100644
--- a/fs/bcachefs/extent_update.c
+++ b/fs/bcachefs/extent_update.c
@@ -99,24 +99,12 @@ int bch2_extent_atomic_end(struct btree_iter *iter,
 			   struct bpos *end)
 {
 	struct btree_trans *trans = iter->trans;
-	struct btree *b;
-	struct btree_node_iter	node_iter;
-	struct bkey_packed	*_k;
-	unsigned		nr_iters = 0;
+	struct btree_iter *copy;
+	struct bkey_s_c k;
+	unsigned nr_iters = 0;
 	int ret;
 
-	ret = bch2_btree_iter_traverse(iter);
-	if (ret)
-		return ret;
-
-	b = iter->l[0].b;
-	node_iter = iter->l[0].iter;
-
-	BUG_ON(bkey_cmp(b->data->min_key, POS_MIN) &&
-	       bkey_cmp(bkey_start_pos(&insert->k),
-			bkey_predecessor(b->data->min_key)) < 0);
-
-	*end = bpos_min(insert->k.p, b->key.k.p);
+	*end = insert->k.p;
 
 	/* extent_update_to_keys(): */
 	nr_iters += 1;
@@ -126,9 +114,9 @@ int bch2_extent_atomic_end(struct btree_iter *iter,
 	if (ret < 0)
 		return ret;
 
-	while ((_k = bch2_btree_node_iter_peek(&node_iter, b))) {
-		struct bkey	unpacked;
-		struct bkey_s_c	k = bkey_disassemble(b, _k, &unpacked);
+	copy = bch2_trans_copy_iter(trans, iter);
+
+	for_each_btree_key_continue(copy, 0, k, ret) {
 		unsigned offset = 0;
 
 		if (bkey_cmp(bkey_start_pos(k.k), *end) >= 0)
@@ -155,10 +143,9 @@ int bch2_extent_atomic_end(struct btree_iter *iter,
 					&nr_iters, EXTENT_ITERS_MAX);
 		if (ret)
 			break;
-
-		bch2_btree_node_iter_advance(&node_iter, b);
 	}
 
+	bch2_trans_iter_put(trans, copy);
 	return ret < 0 ? ret : 0;
 }