diff --git a/fs/bcachefs/btree_update_leaf.c b/fs/bcachefs/btree_update_leaf.c
index 2fc134e34572..b4a2f2e32248 100644
--- a/fs/bcachefs/btree_update_leaf.c
+++ b/fs/bcachefs/btree_update_leaf.c
@@ -941,6 +941,43 @@ int __bch2_trans_commit(struct btree_trans *trans)
 	goto retry;
 }
 
+static int check_pos_snapshot_overwritten(struct btree_trans *trans,
+					  enum btree_id id,
+					  struct bpos pos)
+{
+	struct bch_fs *c = trans->c;
+	struct btree_iter iter;
+	struct bkey_s_c k;
+	int ret;
+
+	if (!snapshot_t(c, pos.snapshot)->children[0])
+		return 0;
+
+	bch2_trans_iter_init(trans, &iter, id, pos,
+			     BTREE_ITER_NOT_EXTENTS|
+			     BTREE_ITER_ALL_SNAPSHOTS);
+	while (1) {
+		k = bch2_btree_iter_prev(&iter);
+		ret = bkey_err(k);
+		if (ret)
+			break;
+
+		if (!k.k)
+			break;
+
+		if (bkey_cmp(pos, k.k->p))
+			break;
+
+		if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, pos.snapshot)) {
+			ret = 1;
+			break;
+		}
+	}
+	bch2_trans_iter_exit(trans, &iter);
+
+	return ret;
+}
+
 static noinline int extent_front_merge(struct btree_trans *trans,
 				       struct btree_iter *iter,
 				       struct bkey_s_c k,
@@ -958,14 +995,40 @@ static noinline int extent_front_merge(struct btree_trans *trans,
 
 	bkey_reassemble(update, k);
 
-	if (bch2_bkey_merge(c, bkey_i_to_s(update), bkey_i_to_s_c(*insert))) {
-		ret = bch2_btree_delete_at(trans, iter, flags);
-		if (ret)
-			return ret;
+	if (!bch2_bkey_merge(c, bkey_i_to_s(update), bkey_i_to_s_c(*insert)))
+		return 0;
 
-		*insert = update;
-	}
+	ret =   check_pos_snapshot_overwritten(trans, iter->btree_id, k.k->p) ?:
+		check_pos_snapshot_overwritten(trans, iter->btree_id, (*insert)->k.p);
+	if (ret < 0)
+		return ret;
+	if (ret)
+		return 0;
 
+	ret = bch2_btree_delete_at(trans, iter, flags);
+	if (ret)
+		return ret;
+
+	*insert = update;
+	return 0;
+}
+
+static noinline int extent_back_merge(struct btree_trans *trans,
+				      struct btree_iter *iter,
+				      struct bkey_i *insert,
+				      struct bkey_s_c k)
+{
+	struct bch_fs *c = trans->c;
+	int ret;
+
+	ret =   check_pos_snapshot_overwritten(trans, iter->btree_id, insert->k.p) ?:
+		check_pos_snapshot_overwritten(trans, iter->btree_id, k.k->p);
+	if (ret < 0)
+		return ret;
+	if (ret)
+		return 0;
+
+	bch2_bkey_merge(c, bkey_i_to_s(insert), k);
 	return 0;
 }
 
@@ -974,7 +1037,6 @@ static int bch2_trans_update_extent(struct btree_trans *trans,
 				    struct bkey_i *insert,
 				    enum btree_update_flags flags)
 {
-	struct bch_fs *c = trans->c;
 	struct btree_iter iter, update_iter;
 	struct bpos start = bkey_start_pos(&insert->k);
 	struct bkey_i *update;
@@ -1002,9 +1064,6 @@ static int bch2_trans_update_extent(struct btree_trans *trans,
 		goto next;
 	}
 
-	if (!bkey_cmp(k.k->p, start))
-		goto next;
-
 	while (bkey_cmp(insert->k.p, bkey_start_pos(k.k)) > 0) {
 		bool front_split = bkey_cmp(bkey_start_pos(k.k), start) < 0;
 		bool back_split  = bkey_cmp(k.k->p, insert->k.p) > 0;
@@ -1120,7 +1179,7 @@ static int bch2_trans_update_extent(struct btree_trans *trans,
 	}
 
 	if (bch2_bkey_maybe_mergable(&insert->k, k.k))
-		bch2_bkey_merge(c, bkey_i_to_s(insert), k);
+		extent_back_merge(trans, &iter, insert, k);
 out:
 	if (!bkey_deleted(&insert->k)) {
 		/*
diff --git a/fs/bcachefs/fsck.c b/fs/bcachefs/fsck.c
index b4a6b3d2ed07..f9a6a0b3ce7a 100644
--- a/fs/bcachefs/fsck.c
+++ b/fs/bcachefs/fsck.c
@@ -473,24 +473,6 @@ static int remove_backpointer(struct btree_trans *trans,
 	return ret;
 }
 
-struct snapshots_seen {
-	struct bpos			pos;
-	size_t				nr;
-	size_t				size;
-	u32				*d;
-};
-
-static void snapshots_seen_exit(struct snapshots_seen *s)
-{
-	kfree(s->d);
-	s->d = NULL;
-}
-
-static void snapshots_seen_init(struct snapshots_seen *s)
-{
-	memset(s, 0, sizeof(*s));
-}
-
 static int snapshots_seen_update(struct bch_fs *c, struct snapshots_seen *s, struct bpos pos)
 {
 	pos.snapshot = snapshot_t(c, pos.snapshot)->equiv;
@@ -499,26 +481,11 @@ static int snapshots_seen_update(struct bch_fs *c, struct snapshots_seen *s, str
 		s->nr = 0;
 	s->pos = pos;
 
-	if (s->nr == s->size) {
-		size_t new_size = max(s->size, 128UL) * 2;
-		u32 *d = krealloc(s->d, new_size * sizeof(s->d[0]), GFP_KERNEL);
-
-		if (!d) {
-			bch_err(c, "error reallocating snapshots_seen table (new size %zu)",
-				new_size);
-			return -ENOMEM;
-		}
-
-		s->size = new_size;
-		s->d	= d;
-	}
-
 	/* Might get called multiple times due to lock restarts */
 	if (s->nr && s->d[s->nr - 1] == pos.snapshot)
 		return 0;
 
-	s->d[s->nr++] = pos.snapshot;
-	return 0;
+	return snapshots_seen_add(c, s, pos.snapshot);
 }
 
 /**
diff --git a/fs/bcachefs/io.c b/fs/bcachefs/io.c
index bd96c6bebe18..002fd35e6bfe 100644
--- a/fs/bcachefs/io.c
+++ b/fs/bcachefs/io.c
@@ -1828,7 +1828,8 @@ static int __bch2_rbio_narrow_crcs(struct btree_trans *trans,
 	if (!bch2_bkey_narrow_crcs(new, new_crc))
 		goto out;
 
-	ret = bch2_trans_update(trans, &iter, new, 0);
+	ret = bch2_trans_update(trans, &iter, new,
+				BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
 out:
 	bch2_trans_iter_exit(trans, &iter);
 	return ret;
diff --git a/fs/bcachefs/migrate.c b/fs/bcachefs/migrate.c
index 1899326d9754..7c764ee4ea09 100644
--- a/fs/bcachefs/migrate.c
+++ b/fs/bcachefs/migrate.c
@@ -48,7 +48,8 @@ static int __bch2_dev_usrdata_drop(struct bch_fs *c, unsigned dev_idx, int flags
 	bch2_trans_init(&trans, c, BTREE_ITER_MAX, 0);
 
 	bch2_trans_iter_init(&trans, &iter, btree_id, POS_MIN,
-			     BTREE_ITER_PREFETCH);
+			     BTREE_ITER_PREFETCH|
+			     BTREE_ITER_ALL_SNAPSHOTS);
 
 	while ((k = bch2_btree_iter_peek(&iter)).k &&
 	       !(ret = bkey_err(k))) {
@@ -74,7 +75,8 @@ static int __bch2_dev_usrdata_drop(struct bch_fs *c, unsigned dev_idx, int flags
 		bch2_btree_iter_set_pos(&iter, bkey_start_pos(&sk.k->k));
 
 		ret   = bch2_btree_iter_traverse(&iter) ?:
-			bch2_trans_update(&trans, &iter, sk.k, 0) ?:
+			bch2_trans_update(&trans, &iter, sk.k,
+					  BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
 			bch2_trans_commit(&trans, NULL, NULL,
 					BTREE_INSERT_NOFAIL);
 
diff --git a/fs/bcachefs/move.c b/fs/bcachefs/move.c
index 9dc6684139de..2e7d8e2fe331 100644
--- a/fs/bcachefs/move.c
+++ b/fs/bcachefs/move.c
@@ -14,6 +14,7 @@
 #include "keylist.h"
 #include "move.h"
 #include "replicas.h"
+#include "subvolume.h"
 #include "super-io.h"
 #include "trace.h"
 
@@ -52,6 +53,81 @@ struct moving_context {
 	wait_queue_head_t	wait;
 };
 
+static int insert_snapshot_whiteouts(struct btree_trans *trans,
+				     enum btree_id id,
+				     struct bpos old_pos,
+				     struct bpos new_pos)
+{
+	struct bch_fs *c = trans->c;
+	struct btree_iter iter, update_iter;
+	struct bkey_s_c k;
+	struct snapshots_seen s;
+	int ret;
+
+	if (!btree_type_has_snapshots(id))
+		return 0;
+
+	snapshots_seen_init(&s);
+
+	if (!bkey_cmp(old_pos, new_pos))
+		return 0;
+
+	if (!snapshot_t(c, old_pos.snapshot)->children[0])
+		return 0;
+
+	bch2_trans_iter_init(trans, &iter, id, old_pos,
+			     BTREE_ITER_NOT_EXTENTS|
+			     BTREE_ITER_ALL_SNAPSHOTS);
+	while (1) {
+next:
+		k = bch2_btree_iter_prev(&iter);
+		ret = bkey_err(k);
+		if (ret)
+			break;
+
+		if (bkey_cmp(old_pos, k.k->p))
+			break;
+
+		if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, old_pos.snapshot)) {
+			struct bkey_i *update;
+			size_t i;
+
+			for (i = 0; i < s.nr; i++)
+				if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, s.d[i]))
+					goto next;
+
+			update = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
+
+			ret = PTR_ERR_OR_ZERO(update);
+			if (ret)
+				break;
+
+			bkey_init(&update->k);
+			update->k.p = new_pos;
+			update->k.p.snapshot = k.k->p.snapshot;
+
+			bch2_trans_iter_init(trans, &update_iter, id, update->k.p,
+					     BTREE_ITER_NOT_EXTENTS|
+					     BTREE_ITER_ALL_SNAPSHOTS|
+					     BTREE_ITER_INTENT);
+			ret   = bch2_btree_iter_traverse(&update_iter) ?:
+				bch2_trans_update(trans, &update_iter, update,
+					  BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+			bch2_trans_iter_exit(trans, &update_iter);
+			if (ret)
+				break;
+
+			ret = snapshots_seen_add(c, &s, k.k->p.snapshot);
+			if (ret)
+				break;
+		}
+	}
+	bch2_trans_iter_exit(trans, &iter);
+	kfree(s.d);
+
+	return ret;
+}
+
 int bch2_migrate_index_update(struct bch_write_op *op)
 {
 	struct bch_fs *c = op->c;
@@ -165,7 +241,10 @@ int bch2_migrate_index_update(struct bch_write_op *op)
 
 		next_pos = insert->k.p;
 
-		ret   = bch2_trans_update(&trans, &iter, insert, 0) ?:
+		ret   = insert_snapshot_whiteouts(&trans, m->btree_id,
+						  k.k->p, insert->k.p) ?:
+			bch2_trans_update(&trans, &iter, insert,
+				BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
 			bch2_trans_commit(&trans, &op->res,
 				op_journal_seq(op),
 				BTREE_INSERT_NOFAIL|
diff --git a/fs/bcachefs/subvolume.h b/fs/bcachefs/subvolume.h
index cea4c665af32..0740c7b7f772 100644
--- a/fs/bcachefs/subvolume.h
+++ b/fs/bcachefs/subvolume.h
@@ -54,6 +54,44 @@ static inline bool bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ances
 	return id == ancestor;
 }
 
+struct snapshots_seen {
+	struct bpos			pos;
+	size_t				nr;
+	size_t				size;
+	u32				*d;
+};
+
+static inline void snapshots_seen_exit(struct snapshots_seen *s)
+{
+	kfree(s->d);
+	s->d = NULL;
+}
+
+static inline void snapshots_seen_init(struct snapshots_seen *s)
+{
+	memset(s, 0, sizeof(*s));
+}
+
+static inline int snapshots_seen_add(struct bch_fs *c, struct snapshots_seen *s, u32 id)
+{
+	if (s->nr == s->size) {
+		size_t new_size = max(s->size, 128UL) * 2;
+		u32 *d = krealloc(s->d, new_size * sizeof(s->d[0]), GFP_KERNEL);
+
+		if (!d) {
+			bch_err(c, "error reallocating snapshots_seen table (new size %zu)",
+				new_size);
+			return -ENOMEM;
+		}
+
+		s->size = new_size;
+		s->d	= d;
+	}
+
+	s->d[s->nr++] = id;
+	return 0;
+}
+
 int bch2_fs_snapshots_check(struct bch_fs *);
 void bch2_fs_snapshots_exit(struct bch_fs *);
 int bch2_fs_snapshots_start(struct bch_fs *);