bcachefs: fix bch2_read_btree()

2 files changed, 12 insertions, 5 deletions

diff --git a/fs/bcachefs/btree_iter.c b/fs/bcachefs/btree_iter.c
index 893fde807c89..465aadbad5ef 100644
--- a/fs/bcachefs/btree_iter.c
+++ b/fs/bcachefs/btree_iter.c
@@ -1335,6 +1335,10 @@ void __bch2_btree_iter_init(struct btree_iter *iter, struct bch_fs *c,
 	iter->l[iter->level].b		= BTREE_ITER_NOT_END;
 	iter->next			= iter;
 
+	if (unlikely((flags & BTREE_ITER_IS_EXTENTS) &&
+		     !bkey_cmp(pos, POS_MAX)))
+		iter->uptodate = BTREE_ITER_END;
+
 	prefetch(c->btree_roots[btree_id].b);
 }
 
diff --git a/fs/bcachefs/debug.c b/fs/bcachefs/debug.c
index 00e0de167b32..7190990dbfa1 100644
--- a/fs/bcachefs/debug.c
+++ b/fs/bcachefs/debug.c
@@ -212,17 +212,20 @@ static ssize_t bch2_read_btree(struct file *file, char __user *buf,
 	if (!i->size)
 		return i->ret;
 
-	for_each_btree_key(&iter, i->c, i->id, i->from,
-			   BTREE_ITER_PREFETCH, k) {
-		i->from = iter.pos;
+	bch2_btree_iter_init(&iter, i->c, i->id, i->from, BTREE_ITER_PREFETCH);
+	k = bch2_btree_iter_peek(&iter);
 
+	while (k.k && !(err = btree_iter_err(k))) {
 		bch2_bkey_val_to_text(i->c, bkey_type(0, i->id),
-				     i->buf, sizeof(i->buf), k);
+				      i->buf, sizeof(i->buf), k);
 		i->bytes = strlen(i->buf);
 		BUG_ON(i->bytes >= PAGE_SIZE);
 		i->buf[i->bytes] = '\n';
 		i->bytes++;
 
+		k = bch2_btree_iter_next(&iter);
+		i->from = iter.pos;
+
 		err = flush_buf(i);
 		if (err)
 			break;
@@ -230,7 +233,7 @@ static ssize_t bch2_read_btree(struct file *file, char __user *buf,
 		if (!i->size)
 			break;
 	}
-	err = bch2_btree_iter_unlock(&iter) ?: err;
+	bch2_btree_iter_unlock(&iter);
 
 	return err < 0 ? err : i->ret;
 }