1 files changed, 75 insertions, 68 deletions

diff --git a/fs/bcachefs/dirent.c b/fs/bcachefs/dirent.c
index 4ae1e9f002a0..d37bd07afbfe 100644
--- a/fs/bcachefs/dirent.c
+++ b/fs/bcachefs/dirent.c
@@ -144,19 +144,21 @@ fsck_err:
 	return ret;
 }
 
-void bch2_dirent_to_text(struct printbuf *out, struct bch_fs *c,
-			 struct bkey_s_c k)
+void bch2_dirent_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c k)
 {
 	struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
 	struct qstr d_name = bch2_dirent_get_name(d);
 
-	prt_printf(out, "%.*s -> %llu type %s",
-	       d_name.len,
-	       d_name.name,
-	       d.v->d_type != DT_SUBVOL
-	       ? le64_to_cpu(d.v->d_inum)
-	       : le32_to_cpu(d.v->d_child_subvol),
-	       bch2_d_type_str(d.v->d_type));
+	prt_printf(out, "%.*s -> ", d_name.len, d_name.name);
+
+	if (d.v->d_type != DT_SUBVOL)
+		prt_printf(out, "%llu", le64_to_cpu(d.v->d_inum));
+	else
+		prt_printf(out, "%u -> %u",
+			   le32_to_cpu(d.v->d_parent_subvol),
+			   le32_to_cpu(d.v->d_child_subvol));
+
+	prt_printf(out, " type %s", bch2_d_type_str(d.v->d_type));
 }
 
 static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
@@ -199,17 +201,17 @@ static struct bkey_i_dirent *dirent_create_key(struct btree_trans *trans,
 }
 
 int bch2_dirent_create_snapshot(struct btree_trans *trans,
-			u64 dir, u32 snapshot,
+			u32 dir_subvol, u64 dir, u32 snapshot,
 			const struct bch_hash_info *hash_info,
 			u8 type, const struct qstr *name, u64 dst_inum,
 			u64 *dir_offset,
 			bch_str_hash_flags_t str_hash_flags)
 {
-	subvol_inum zero_inum = { 0 };
+	subvol_inum dir_inum = { .subvol = dir_subvol, .inum = dir };
 	struct bkey_i_dirent *dirent;
 	int ret;
 
-	dirent = dirent_create_key(trans, zero_inum, type, name, dst_inum);
+	dirent = dirent_create_key(trans, dir_inum, type, name, dst_inum);
 	ret = PTR_ERR_OR_ZERO(dirent);
 	if (ret)
 		return ret;
@@ -217,10 +219,10 @@ int bch2_dirent_create_snapshot(struct btree_trans *trans,
 	dirent->k.p.inode	= dir;
 	dirent->k.p.snapshot	= snapshot;
 
-	ret = bch2_hash_set_snapshot(trans, bch2_dirent_hash_desc, hash_info,
-				     zero_inum, snapshot,
-				     &dirent->k_i, str_hash_flags,
-				     BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+	ret = bch2_hash_set_in_snapshot(trans, bch2_dirent_hash_desc, hash_info,
+					dir_inum, snapshot,
+					&dirent->k_i, str_hash_flags,
+					BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
 	*dir_offset = dirent->k.p.offset;
 
 	return ret;
@@ -291,12 +293,10 @@ int bch2_dirent_rename(struct btree_trans *trans,
 	struct bkey_i_dirent *new_src = NULL, *new_dst = NULL;
 	struct bpos dst_pos =
 		POS(dst_dir.inum, bch2_dirent_hash(dst_hash, dst_name));
-	unsigned src_type = 0, dst_type = 0, src_update_flags = 0;
+	unsigned src_update_flags = 0;
+	bool delete_src, delete_dst;
 	int ret = 0;
 
-	if (src_dir.subvol != dst_dir.subvol)
-		return -EXDEV;
-
 	memset(src_inum, 0, sizeof(*src_inum));
 	memset(dst_inum, 0, sizeof(*dst_inum));
 
@@ -317,12 +317,6 @@ int bch2_dirent_rename(struct btree_trans *trans,
 	if (ret)
 		goto out;
 
-	src_type = bkey_s_c_to_dirent(old_src).v->d_type;
-
-	if (src_type == DT_SUBVOL && mode == BCH_RENAME_EXCHANGE)
-		return -EOPNOTSUPP;
-
-
 	/* Lookup dst: */
 	if (mode == BCH_RENAME) {
 		/*
@@ -350,11 +344,6 @@ int bch2_dirent_rename(struct btree_trans *trans,
 				bkey_s_c_to_dirent(old_dst), dst_inum);
 		if (ret)
 			goto out;
-
-		dst_type = bkey_s_c_to_dirent(old_dst).v->d_type;
-
-		if (dst_type == DT_SUBVOL)
-			return -EOPNOTSUPP;
 	}
 
 	if (mode != BCH_RENAME_EXCHANGE)
@@ -424,28 +413,55 @@ int bch2_dirent_rename(struct btree_trans *trans,
 		}
 	}
 
+	if (new_dst->v.d_type == DT_SUBVOL)
+		new_dst->v.d_parent_subvol = cpu_to_le32(dst_dir.subvol);
+
+	if ((mode == BCH_RENAME_EXCHANGE) &&
+	    new_src->v.d_type == DT_SUBVOL)
+		new_src->v.d_parent_subvol = cpu_to_le32(src_dir.subvol);
+
 	ret = bch2_trans_update(trans, &dst_iter, &new_dst->k_i, 0);
 	if (ret)
 		goto out;
 out_set_src:
-
 	/*
-	 * If we're deleting a subvolume, we need to really delete the dirent,
-	 * not just emit a whiteout in the current snapshot:
+	 * If we're deleting a subvolume we need to really delete the dirent,
+	 * not just emit a whiteout in the current snapshot - there can only be
+	 * single dirent that points to a given subvolume.
+	 *
+	 * IOW, we don't maintain multiple versions in different snapshots of
+	 * dirents that point to subvolumes - dirents that point to subvolumes
+	 * are only visible in one particular subvolume so it's not necessary,
+	 * and it would be particularly confusing for fsck to have to deal with.
 	 */
-	if (src_type == DT_SUBVOL) {
-		bch2_btree_iter_set_snapshot(&src_iter, old_src.k->p.snapshot);
-		ret = bch2_btree_iter_traverse(&src_iter);
+	delete_src = bkey_s_c_to_dirent(old_src).v->d_type == DT_SUBVOL &&
+		new_src->k.p.snapshot != old_src.k->p.snapshot;
+
+	delete_dst = old_dst.k &&
+		bkey_s_c_to_dirent(old_dst).v->d_type == DT_SUBVOL &&
+		new_dst->k.p.snapshot != old_dst.k->p.snapshot;
+
+	if (!delete_src || !bkey_deleted(&new_src->k)) {
+		ret = bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags);
 		if (ret)
 			goto out;
+	}
 
-		new_src->k.p = src_iter.pos;
-		src_update_flags |= BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE;
+	if (delete_src) {
+		bch2_btree_iter_set_snapshot(&src_iter, old_src.k->p.snapshot);
+		ret =   bch2_btree_iter_traverse(&src_iter) ?:
+			bch2_btree_delete_at(trans, &src_iter, BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+		if (ret)
+			goto out;
 	}
 
-	ret = bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags);
-	if (ret)
-		goto out;
+	if (delete_dst) {
+		bch2_btree_iter_set_snapshot(&dst_iter, old_dst.k->p.snapshot);
+		ret =   bch2_btree_iter_traverse(&dst_iter) ?:
+			bch2_btree_delete_at(trans, &dst_iter, BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
+		if (ret)
+			goto out;
+	}
 
 	if (mode == BCH_RENAME_EXCHANGE)
 		*src_offset = new_src->k.p.offset;
@@ -456,41 +472,29 @@ out:
 	return ret;
 }
 
-int __bch2_dirent_lookup_trans(struct btree_trans *trans,
-			       struct btree_iter *iter,
-			       subvol_inum dir,
-			       const struct bch_hash_info *hash_info,
-			       const struct qstr *name, subvol_inum *inum,
-			       unsigned flags)
+int bch2_dirent_lookup_trans(struct btree_trans *trans,
+			     struct btree_iter *iter,
+			     subvol_inum dir,
+			     const struct bch_hash_info *hash_info,
+			     const struct qstr *name, subvol_inum *inum,
+			     unsigned flags)
 {
-	struct bkey_s_c k;
-	struct bkey_s_c_dirent d;
-	u32 snapshot;
-	int ret;
-
-	ret = bch2_subvolume_get_snapshot(trans, dir.subvol, &snapshot);
-	if (ret)
-		return ret;
-
-	ret = bch2_hash_lookup(trans, iter, bch2_dirent_hash_desc,
-			       hash_info, dir, name, flags);
+	int ret = bch2_hash_lookup(trans, iter, bch2_dirent_hash_desc,
+				   hash_info, dir, name, flags);
 	if (ret)
 		return ret;
 
-	k = bch2_btree_iter_peek_slot(iter);
+	struct bkey_s_c k = bch2_btree_iter_peek_slot(iter);
 	ret = bkey_err(k);
 	if (ret)
 		goto err;
 
-	d = bkey_s_c_to_dirent(k);
-
-	ret = bch2_dirent_read_target(trans, dir, d, inum);
+	ret = bch2_dirent_read_target(trans, dir, bkey_s_c_to_dirent(k), inum);
 	if (ret > 0)
 		ret = -ENOENT;
 err:
 	if (ret)
 		bch2_trans_iter_exit(trans, iter);
-
 	return ret;
 }
 
@@ -502,13 +506,13 @@ u64 bch2_dirent_lookup(struct bch_fs *c, subvol_inum dir,
 	struct btree_iter iter = { NULL };
 
 	int ret = lockrestart_do(trans,
-		__bch2_dirent_lookup_trans(trans, &iter, dir, hash_info, name, inum, 0));
+		bch2_dirent_lookup_trans(trans, &iter, dir, hash_info, name, inum, 0));
 	bch2_trans_iter_exit(trans, &iter);
 	bch2_trans_put(trans);
 	return ret;
 }
 
-int bch2_empty_dir_snapshot(struct btree_trans *trans, u64 dir, u32 snapshot)
+int bch2_empty_dir_snapshot(struct btree_trans *trans, u64 dir, u32 subvol, u32 snapshot)
 {
 	struct btree_iter iter;
 	struct bkey_s_c k;
@@ -518,7 +522,10 @@ int bch2_empty_dir_snapshot(struct btree_trans *trans, u64 dir, u32 snapshot)
 			   SPOS(dir, 0, snapshot),
 			   POS(dir, U64_MAX), 0, k, ret)
 		if (k.k->type == KEY_TYPE_dirent) {
-			ret = -ENOTEMPTY;
+			struct bkey_s_c_dirent d = bkey_s_c_to_dirent(k);
+			if (d.v->d_type == DT_SUBVOL && le32_to_cpu(d.v->d_parent_subvol) != subvol)
+				continue;
+			ret = -BCH_ERR_ENOTEMPTY_dir_not_empty;
 			break;
 		}
 	bch2_trans_iter_exit(trans, &iter);
@@ -531,7 +538,7 @@ int bch2_empty_dir_trans(struct btree_trans *trans, subvol_inum dir)
 	u32 snapshot;
 
 	return bch2_subvolume_get_snapshot(trans, dir.subvol, &snapshot) ?:
-		bch2_empty_dir_snapshot(trans, dir.inum, snapshot);
+		bch2_empty_dir_snapshot(trans, dir.inum, dir.subvol, snapshot);
 }
 
 int bch2_readdir(struct bch_fs *c, subvol_inum inum, struct dir_context *ctx)