1 files changed, 199 insertions, 125 deletions

diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index b2f5f2e50f7e..c4a5e83a56a4 100644
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -2,6 +2,7 @@
 
 #include "bcachefs.h"
 #include "alloc_foreground.h"
+#include "bkey_buf.h"
 #include "bkey_methods.h"
 #include "btree_cache.h"
 #include "btree_gc.h"
@@ -18,12 +19,20 @@
 #include "journal.h"
 #include "journal_reclaim.h"
 #include "keylist.h"
+#include "recovery_passes.h"
 #include "replicas.h"
 #include "super-io.h"
 #include "trace.h"
 
 #include <linux/random.h>
 
+static const char * const bch2_btree_update_modes[] = {
+#define x(t) #t,
+	BTREE_UPDATE_MODES()
+#undef x
+	NULL
+};
+
 static int bch2_btree_insert_node(struct btree_update *, struct btree_trans *,
 				  btree_path_idx_t, struct btree *, struct keylist *);
 static void bch2_btree_update_add_new_node(struct btree_update *, struct btree *);
@@ -44,56 +53,103 @@ static btree_path_idx_t get_unlocked_mut_path(struct btree_trans *trans,
 	return path_idx;
 }
 
-/* Debug code: */
-
 /*
  * Verify that child nodes correctly span parent node's range:
  */
-static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
+int bch2_btree_node_check_topology(struct btree_trans *trans, struct btree *b)
 {
-#ifdef CONFIG_BCACHEFS_DEBUG
-	struct bpos next_node = b->data->min_key;
-	struct btree_node_iter iter;
+	struct bch_fs *c = trans->c;
+	struct bpos node_min = b->key.k.type == KEY_TYPE_btree_ptr_v2
+		? bkey_i_to_btree_ptr_v2(&b->key)->v.min_key
+		: b->data->min_key;
+	struct btree_and_journal_iter iter;
 	struct bkey_s_c k;
-	struct bkey_s_c_btree_ptr_v2 bp;
-	struct bkey unpacked;
-	struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
+	struct printbuf buf = PRINTBUF;
+	struct bkey_buf prev;
+	int ret = 0;
 
-	BUG_ON(!b->c.level);
+	BUG_ON(b->key.k.type == KEY_TYPE_btree_ptr_v2 &&
+	       !bpos_eq(bkey_i_to_btree_ptr_v2(&b->key)->v.min_key,
+			b->data->min_key));
 
-	if (!test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags))
-		return;
+	if (!b->c.level)
+		return 0;
 
-	bch2_btree_node_iter_init_from_start(&iter, b);
+	bch2_bkey_buf_init(&prev);
+	bkey_init(&prev.k->k);
+	bch2_btree_and_journal_iter_init_node_iter(trans, &iter, b);
 
-	while (1) {
-		k = bch2_btree_node_iter_peek_unpack(&iter, b, &unpacked);
+	while ((k = bch2_btree_and_journal_iter_peek(&iter)).k) {
 		if (k.k->type != KEY_TYPE_btree_ptr_v2)
-			break;
-		bp = bkey_s_c_to_btree_ptr_v2(k);
+			goto out;
 
-		if (!bpos_eq(next_node, bp.v->min_key)) {
-			bch2_dump_btree_node(c, b);
-			bch2_bpos_to_text(&buf1, next_node);
-			bch2_bpos_to_text(&buf2, bp.v->min_key);
-			panic("expected next min_key %s got %s\n", buf1.buf, buf2.buf);
-		}
+		struct bkey_s_c_btree_ptr_v2 bp = bkey_s_c_to_btree_ptr_v2(k);
 
-		bch2_btree_node_iter_advance(&iter, b);
+		struct bpos expected_min = bkey_deleted(&prev.k->k)
+			? node_min
+			: bpos_successor(prev.k->k.p);
 
-		if (bch2_btree_node_iter_end(&iter)) {
-			if (!bpos_eq(k.k->p, b->key.k.p)) {
-				bch2_dump_btree_node(c, b);
-				bch2_bpos_to_text(&buf1, b->key.k.p);
-				bch2_bpos_to_text(&buf2, k.k->p);
-				panic("expected end %s got %s\n", buf1.buf, buf2.buf);
-			}
-			break;
+		if (!bpos_eq(expected_min, bp.v->min_key)) {
+			bch2_topology_error(c);
+
+			printbuf_reset(&buf);
+			prt_str(&buf, "end of prev node doesn't match start of next node\n"),
+			prt_printf(&buf, "  in btree %s level %u node ",
+				   bch2_btree_id_str(b->c.btree_id), b->c.level);
+			bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
+			prt_str(&buf, "\n  prev ");
+			bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(prev.k));
+			prt_str(&buf, "\n  next ");
+			bch2_bkey_val_to_text(&buf, c, k);
+
+			need_fsck_err(c, btree_node_topology_bad_min_key, "%s", buf.buf);
+			goto topology_repair;
 		}
 
-		next_node = bpos_successor(k.k->p);
+		bch2_bkey_buf_reassemble(&prev, c, k);
+		bch2_btree_and_journal_iter_advance(&iter);
 	}
-#endif
+
+	if (bkey_deleted(&prev.k->k)) {
+		bch2_topology_error(c);
+
+		printbuf_reset(&buf);
+		prt_str(&buf, "empty interior node\n");
+		prt_printf(&buf, "  in btree %s level %u node ",
+			   bch2_btree_id_str(b->c.btree_id), b->c.level);
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
+
+		need_fsck_err(c, btree_node_topology_empty_interior_node, "%s", buf.buf);
+		goto topology_repair;
+	} else if (!bpos_eq(prev.k->k.p, b->key.k.p)) {
+		bch2_topology_error(c);
+
+		printbuf_reset(&buf);
+		prt_str(&buf, "last child node doesn't end at end of parent node\n");
+		prt_printf(&buf, "  in btree %s level %u node ",
+			   bch2_btree_id_str(b->c.btree_id), b->c.level);
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
+		prt_str(&buf, "\n  last key ");
+		bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(prev.k));
+
+		need_fsck_err(c, btree_node_topology_bad_max_key, "%s", buf.buf);
+		goto topology_repair;
+	}
+out:
+fsck_err:
+	bch2_btree_and_journal_iter_exit(&iter);
+	bch2_bkey_buf_exit(&prev, c);
+	printbuf_exit(&buf);
+	return ret;
+topology_repair:
+	if ((c->recovery_passes_explicit & BIT_ULL(BCH_RECOVERY_PASS_check_topology)) &&
+	    c->curr_recovery_pass > BCH_RECOVERY_PASS_check_topology) {
+		bch2_inconsistent_error(c);
+		ret = -BCH_ERR_btree_need_topology_repair;
+	} else {
+		ret = bch2_run_explicit_recovery_pass(c, BCH_RECOVERY_PASS_check_topology);
+	}
+	goto out;
 }
 
 /* Calculate ideal packed bkey format for new btree nodes: */
@@ -254,7 +310,7 @@ static struct btree *__bch2_btree_node_alloc(struct btree_trans *trans,
 	struct open_buckets obs = { .nr = 0 };
 	struct bch_devs_list devs_have = (struct bch_devs_list) { 0 };
 	enum bch_watermark watermark = flags & BCH_WATERMARK_MASK;
-	unsigned nr_reserve = watermark > BCH_WATERMARK_reclaim
+	unsigned nr_reserve = watermark < BCH_WATERMARK_reclaim
 		? BTREE_NODE_RESERVE
 		: 0;
 	int ret;
@@ -638,7 +694,7 @@ static void btree_update_nodes_written(struct btree_update *as)
 	 * which may require allocations as well.
 	 */
 	ret = commit_do(trans, &as->disk_res, &journal_seq,
-			BCH_WATERMARK_reclaim|
+			BCH_WATERMARK_interior_updates|
 			BCH_TRANS_COMMIT_no_enospc|
 			BCH_TRANS_COMMIT_no_check_rw|
 			BCH_TRANS_COMMIT_journal_reclaim,
@@ -648,9 +704,13 @@ static void btree_update_nodes_written(struct btree_update *as)
 	bch2_fs_fatal_err_on(ret && !bch2_journal_error(&c->journal), c,
 			     "%s", bch2_err_str(ret));
 err:
-	if (as->b) {
-
-		b = as->b;
+	/*
+	 * We have to be careful because another thread might be getting ready
+	 * to free as->b and calling btree_update_reparent() on us - we'll
+	 * recheck under btree_update_lock below:
+	 */
+	b = READ_ONCE(as->b);
+	if (b) {
 		btree_path_idx_t path_idx = get_unlocked_mut_path(trans,
 						as->btree_id, b->c.level, b->key.k.p);
 		struct btree_path *path = trans->paths + path_idx;
@@ -794,15 +854,17 @@ static void btree_update_updated_node(struct btree_update *as, struct btree *b)
 {
 	struct bch_fs *c = as->c;
 
-	mutex_lock(&c->btree_interior_update_lock);
-	list_add_tail(&as->unwritten_list, &c->btree_interior_updates_unwritten);
-
-	BUG_ON(as->mode != BTREE_INTERIOR_NO_UPDATE);
+	BUG_ON(as->mode != BTREE_UPDATE_none);
+	BUG_ON(as->update_level_end < b->c.level);
 	BUG_ON(!btree_node_dirty(b));
 	BUG_ON(!b->c.level);
 
-	as->mode	= BTREE_INTERIOR_UPDATING_NODE;
+	mutex_lock(&c->btree_interior_update_lock);
+	list_add_tail(&as->unwritten_list, &c->btree_interior_updates_unwritten);
+
+	as->mode	= BTREE_UPDATE_node;
 	as->b		= b;
+	as->update_level_end = b->c.level;
 
 	set_btree_node_write_blocked(b);
 	list_add(&as->write_blocked_list, &b->write_blocked);
@@ -824,7 +886,7 @@ static void btree_update_reparent(struct btree_update *as,
 	lockdep_assert_held(&c->btree_interior_update_lock);
 
 	child->b = NULL;
-	child->mode = BTREE_INTERIOR_UPDATING_AS;
+	child->mode = BTREE_UPDATE_update;
 
 	bch2_journal_pin_copy(&c->journal, &as->journal, &child->journal,
 			      bch2_update_reparent_journal_pin_flush);
@@ -835,7 +897,7 @@ static void btree_update_updated_root(struct btree_update *as, struct btree *b)
 	struct bkey_i *insert = &b->key;
 	struct bch_fs *c = as->c;
 
-	BUG_ON(as->mode != BTREE_INTERIOR_NO_UPDATE);
+	BUG_ON(as->mode != BTREE_UPDATE_none);
 
 	BUG_ON(as->journal_u64s + jset_u64s(insert->k.u64s) >
 	       ARRAY_SIZE(as->journal_entries));
@@ -849,7 +911,7 @@ static void btree_update_updated_root(struct btree_update *as, struct btree *b)
 	mutex_lock(&c->btree_interior_update_lock);
 	list_add_tail(&as->unwritten_list, &c->btree_interior_updates_unwritten);
 
-	as->mode	= BTREE_INTERIOR_UPDATING_ROOT;
+	as->mode	= BTREE_UPDATE_root;
 	mutex_unlock(&c->btree_interior_update_lock);
 }
 
@@ -1027,7 +1089,7 @@ static void bch2_btree_update_done(struct btree_update *as, struct btree_trans *
 	struct bch_fs *c = as->c;
 	u64 start_time = as->start_time;
 
-	BUG_ON(as->mode == BTREE_INTERIOR_NO_UPDATE);
+	BUG_ON(as->mode == BTREE_UPDATE_none);
 
 	if (as->took_gc_lock)
 		up_read(&as->c->gc_lock);
@@ -1044,7 +1106,7 @@ static void bch2_btree_update_done(struct btree_update *as, struct btree_trans *
 
 static struct btree_update *
 bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
-			unsigned level, bool split, unsigned flags)
+			unsigned level_start, bool split, unsigned flags)
 {
 	struct bch_fs *c = trans->c;
 	struct btree_update *as;
@@ -1052,7 +1114,7 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 	int disk_res_flags = (flags & BCH_TRANS_COMMIT_no_enospc)
 		? BCH_DISK_RESERVATION_NOFAIL : 0;
 	unsigned nr_nodes[2] = { 0, 0 };
-	unsigned update_level = level;
+	unsigned level_end = level_start;
 	enum bch_watermark watermark = flags & BCH_WATERMARK_MASK;
 	int ret = 0;
 	u32 restart_count = trans->restart_count;
@@ -1067,34 +1129,30 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 	flags &= ~BCH_WATERMARK_MASK;
 	flags |= watermark;
 
-	if (watermark < c->journal.watermark) {
-		struct journal_res res = { 0 };
-		unsigned journal_flags = watermark|JOURNAL_RES_GET_CHECK;
-
-		if ((flags & BCH_TRANS_COMMIT_journal_reclaim) &&
-		    watermark != BCH_WATERMARK_reclaim)
-			journal_flags |= JOURNAL_RES_GET_NONBLOCK;
+	if (watermark < BCH_WATERMARK_reclaim &&
+	    test_bit(JOURNAL_SPACE_LOW, &c->journal.flags)) {
+		if (flags & BCH_TRANS_COMMIT_journal_reclaim)
+			return ERR_PTR(-BCH_ERR_journal_reclaim_would_deadlock);
 
-		ret = drop_locks_do(trans,
-			bch2_journal_res_get(&c->journal, &res, 1, journal_flags));
-		if (bch2_err_matches(ret, BCH_ERR_operation_blocked))
-			ret = -BCH_ERR_journal_reclaim_would_deadlock;
+		bch2_trans_unlock(trans);
+		wait_event(c->journal.wait, !test_bit(JOURNAL_SPACE_LOW, &c->journal.flags));
+		ret = bch2_trans_relock(trans);
 		if (ret)
 			return ERR_PTR(ret);
 	}
 
 	while (1) {
-		nr_nodes[!!update_level] += 1 + split;
-		update_level++;
+		nr_nodes[!!level_end] += 1 + split;
+		level_end++;
 
-		ret = bch2_btree_path_upgrade(trans, path, update_level + 1);
+		ret = bch2_btree_path_upgrade(trans, path, level_end + 1);
 		if (ret)
 			return ERR_PTR(ret);
 
-		if (!btree_path_node(path, update_level)) {
+		if (!btree_path_node(path, level_end)) {
 			/* Allocating new root? */
 			nr_nodes[1] += split;
-			update_level = BTREE_MAX_DEPTH;
+			level_end = BTREE_MAX_DEPTH;
 			break;
 		}
 
@@ -1102,11 +1160,11 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 		 * Always check for space for two keys, even if we won't have to
 		 * split at prior level - it might have been a merge instead:
 		 */
-		if (bch2_btree_node_insert_fits(path->l[update_level].b,
+		if (bch2_btree_node_insert_fits(path->l[level_end].b,
 						BKEY_BTREE_PTR_U64s_MAX * 2))
 			break;
 
-		split = path->l[update_level].b->nr.live_u64s > BTREE_SPLIT_THRESHOLD(c);
+		split = path->l[level_end].b->nr.live_u64s > BTREE_SPLIT_THRESHOLD(c);
 	}
 
 	if (!down_read_trylock(&c->gc_lock)) {
@@ -1120,13 +1178,15 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 	as = mempool_alloc(&c->btree_interior_update_pool, GFP_NOFS);
 	memset(as, 0, sizeof(*as));
 	closure_init(&as->cl, NULL);
-	as->c		= c;
-	as->start_time	= start_time;
-	as->ip_started	= _RET_IP_;
-	as->mode	= BTREE_INTERIOR_NO_UPDATE;
-	as->took_gc_lock = true;
-	as->btree_id	= path->btree_id;
-	as->update_level = update_level;
+	as->c			= c;
+	as->start_time		= start_time;
+	as->ip_started		= _RET_IP_;
+	as->mode		= BTREE_UPDATE_none;
+	as->watermark		= watermark;
+	as->took_gc_lock	= true;
+	as->btree_id		= path->btree_id;
+	as->update_level_start	= level_start;
+	as->update_level_end	= level_end;
 	INIT_LIST_HEAD(&as->list);
 	INIT_LIST_HEAD(&as->unwritten_list);
 	INIT_LIST_HEAD(&as->write_blocked_list);
@@ -1168,7 +1228,7 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 		 */
 		if (bch2_err_matches(ret, ENOSPC) &&
 		    (flags & BCH_TRANS_COMMIT_journal_reclaim) &&
-		    watermark != BCH_WATERMARK_reclaim) {
+		    watermark < BCH_WATERMARK_reclaim) {
 			ret = -BCH_ERR_journal_reclaim_would_deadlock;
 			goto err;
 		}
@@ -1316,12 +1376,12 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as,
 }
 
 static void
-__bch2_btree_insert_keys_interior(struct btree_update *as,
-				  struct btree_trans *trans,
-				  struct btree_path *path,
-				  struct btree *b,
-				  struct btree_node_iter node_iter,
-				  struct keylist *keys)
+bch2_btree_insert_keys_interior(struct btree_update *as,
+				struct btree_trans *trans,
+				struct btree_path *path,
+				struct btree *b,
+				struct btree_node_iter node_iter,
+				struct keylist *keys)
 {
 	struct bkey_i *insert = bch2_keylist_front(keys);
 	struct bkey_packed *k;
@@ -1380,9 +1440,16 @@ static void __btree_split_node(struct btree_update *as,
 		if (bkey_deleted(k))
 			continue;
 
+		uk = bkey_unpack_key(b, k);
+
+		if (b->c.level &&
+		    u64s < n1_u64s &&
+		    u64s + k->u64s >= n1_u64s &&
+		    bch2_key_deleted_in_journal(trans, b->c.btree_id, b->c.level, uk.p))
+			n1_u64s += k->u64s;
+
 		i = u64s >= n1_u64s;
 		u64s += k->u64s;
-		uk = bkey_unpack_key(b, k);
 		if (!i)
 			n1_pos = uk.p;
 		bch2_bkey_format_add_key(&format[i], &uk);
@@ -1441,8 +1508,7 @@ static void __btree_split_node(struct btree_update *as,
 
 		bch2_verify_btree_nr_keys(n[i]);
 
-		if (b->c.level)
-			btree_node_interior_verify(as->c, n[i]);
+		BUG_ON(bch2_btree_node_check_topology(trans, n[i]));
 	}
 }
 
@@ -1471,9 +1537,9 @@ static void btree_split_insert_keys(struct btree_update *as,
 
 		bch2_btree_node_iter_init(&node_iter, b, &bch2_keylist_front(keys)->k.p);
 
-		__bch2_btree_insert_keys_interior(as, trans, path, b, node_iter, keys);
+		bch2_btree_insert_keys_interior(as, trans, path, b, node_iter, keys);
 
-		btree_node_interior_verify(as->c, b);
+		BUG_ON(bch2_btree_node_check_topology(trans, b));
 	}
 }
 
@@ -1488,9 +1554,14 @@ static int btree_split(struct btree_update *as, struct btree_trans *trans,
 	u64 start_time = local_clock();
 	int ret = 0;
 
+	bch2_verify_btree_nr_keys(b);
 	BUG_ON(!parent && (b != btree_node_root(c, b)));
 	BUG_ON(parent && !btree_node_intent_locked(trans->paths + path, b->c.level + 1));
 
+	ret = bch2_btree_node_check_topology(trans, b);
+	if (ret)
+		return ret;
+
 	bch2_btree_interior_update_will_free_node(as, b);
 
 	if (b->nr.live_u64s > BTREE_SPLIT_THRESHOLD(c)) {
@@ -1646,27 +1717,6 @@ err:
 	goto out;
 }
 
-static void
-bch2_btree_insert_keys_interior(struct btree_update *as,
-				struct btree_trans *trans,
-				struct btree_path *path,
-				struct btree *b,
-				struct keylist *keys)
-{
-	struct btree_path *linked;
-	unsigned i;
-
-	__bch2_btree_insert_keys_interior(as, trans, path, b,
-					  path->l[b->c.level].iter, keys);
-
-	btree_update_updated_node(as, b);
-
-	trans_for_each_path_with_node(trans, b, linked, i)
-		bch2_btree_node_iter_peek(&linked->l[b->c.level].iter, b);
-
-	bch2_trans_verify_paths(trans);
-}
-
 /**
  * bch2_btree_insert_node - insert bkeys into a given btree node
  *
@@ -1687,7 +1737,8 @@ static int bch2_btree_insert_node(struct btree_update *as, struct btree_trans *t
 				  struct keylist *keys)
 {
 	struct bch_fs *c = as->c;
-	struct btree_path *path = trans->paths + path_idx;
+	struct btree_path *path = trans->paths + path_idx, *linked;
+	unsigned i;
 	int old_u64s = le16_to_cpu(btree_bset_last(b)->u64s);
 	int old_live_u64s = b->nr.live_u64s;
 	int live_u64s_added, u64s_added;
@@ -1710,9 +1761,19 @@ static int bch2_btree_insert_node(struct btree_update *as, struct btree_trans *t
 		goto split;
 	}
 
-	btree_node_interior_verify(c, b);
+	ret = bch2_btree_node_check_topology(trans, b);
+	if (ret) {
+		bch2_btree_node_unlock_write(trans, path, b);
+		return ret;
+	}
 
-	bch2_btree_insert_keys_interior(as, trans, path, b, keys);
+	bch2_btree_insert_keys_interior(as, trans, path, b,
+					path->l[b->c.level].iter, keys);
+
+	trans_for_each_path_with_node(trans, b, linked, i)
+		bch2_btree_node_iter_peek(&linked->l[b->c.level].iter, b);
+
+	bch2_trans_verify_paths(trans);
 
 	live_u64s_added = (int) b->nr.live_u64s - old_live_u64s;
 	u64s_added = (int) le16_to_cpu(btree_bset_last(b)->u64s) - old_u64s;
@@ -1726,16 +1787,17 @@ static int bch2_btree_insert_node(struct btree_update *as, struct btree_trans *t
 	    bch2_maybe_compact_whiteouts(c, b))
 		bch2_trans_node_reinit_iter(trans, b);
 
+	btree_update_updated_node(as, b);
 	bch2_btree_node_unlock_write(trans, path, b);
 
-	btree_node_interior_verify(c, b);
+	BUG_ON(bch2_btree_node_check_topology(trans, b));
 	return 0;
 split:
 	/*
 	 * We could attempt to avoid the transaction restart, by calling
 	 * bch2_btree_path_upgrade() and allocating more nodes:
 	 */
-	if (b->c.level >= as->update_level) {
+	if (b->c.level >= as->update_level_end) {
 		trace_and_count(c, trans_restart_split_race, trans, _THIS_IP_, b);
 		return btree_trans_restart(trans, BCH_ERR_transaction_restart_split_race);
 	}
@@ -1818,9 +1880,12 @@ int bch2_btree_increase_depth(struct btree_trans *trans, btree_path_idx_t path,
 {
 	struct bch_fs *c = trans->c;
 	struct btree *b = bch2_btree_id_root(c, trans->paths[path].btree_id)->b;
+
+	if (btree_node_fake(b))
+		return bch2_btree_split_leaf(trans, path, flags);
+
 	struct btree_update *as =
-		bch2_btree_update_start(trans, trans->paths + path,
-					b->c.level, true, flags);
+		bch2_btree_update_start(trans, trans->paths + path, b->c.level, true, flags);
 	if (IS_ERR(as))
 		return PTR_ERR(as);
 
@@ -2391,7 +2456,7 @@ void bch2_btree_set_root_for_read(struct bch_fs *c, struct btree *b)
 	bch2_btree_set_root_inmem(c, b);
 }
 
-static int __bch2_btree_root_alloc(struct btree_trans *trans, enum btree_id id)
+static int __bch2_btree_root_alloc_fake(struct btree_trans *trans, enum btree_id id, unsigned level)
 {
 	struct bch_fs *c = trans->c;
 	struct closure cl;
@@ -2410,7 +2475,7 @@ static int __bch2_btree_root_alloc(struct btree_trans *trans, enum btree_id id)
 
 	set_btree_node_fake(b);
 	set_btree_node_need_rewrite(b);
-	b->c.level	= 0;
+	b->c.level	= level;
 	b->c.btree_id	= id;
 
 	bkey_btree_ptr_init(&b->key);
@@ -2437,9 +2502,23 @@ static int __bch2_btree_root_alloc(struct btree_trans *trans, enum btree_id id)
 	return 0;
 }
 
-void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
+void bch2_btree_root_alloc_fake(struct bch_fs *c, enum btree_id id, unsigned level)
+{
+	bch2_trans_run(c, __bch2_btree_root_alloc_fake(trans, id, level));
+}
+
+static void bch2_btree_update_to_text(struct printbuf *out, struct btree_update *as)
 {
-	bch2_trans_run(c, __bch2_btree_root_alloc(trans, id));
+	prt_printf(out, "%ps: btree=%s l=%u-%u watermark=%s mode=%s nodes_written=%u cl.remaining=%u journal_seq=%llu\n",
+		   (void *) as->ip_started,
+		   bch2_btree_id_str(as->btree_id),
+		   as->update_level_start,
+		   as->update_level_end,
+		   bch2_watermarks[as->watermark],
+		   bch2_btree_update_modes[as->mode],
+		   as->nodes_written,
+		   closure_nr_remaining(&as->cl),
+		   as->journal.seq);
 }
 
 void bch2_btree_updates_to_text(struct printbuf *out, struct bch_fs *c)
@@ -2448,12 +2527,7 @@ void bch2_btree_updates_to_text(struct printbuf *out, struct bch_fs *c)
 
 	mutex_lock(&c->btree_interior_update_lock);
 	list_for_each_entry(as, &c->btree_interior_update_list, list)
-		prt_printf(out, "%ps: mode=%u nodes_written=%u cl.remaining=%u journal_seq=%llu\n",
-			   (void *) as->ip_started,
-			   as->mode,
-			   as->nodes_written,
-			   closure_nr_remaining(&as->cl),
-			   as->journal.seq);
+		bch2_btree_update_to_text(out, as);
 	mutex_unlock(&c->btree_interior_update_lock);
 }