[PATCH 09/16] btrfs: extract tree roots and zone info initialization into init/exit helpers

[Qu Wenruo <wqu@suse.com>]

No functional change, but one special thing to notice:

- No need to cleanup zone info
  As we call btrfs_close_devices() at error path to cleanup all
  zone device info, thus we don't need to handle it at
  open_ctree_tree_roots_init().

  This is a break of the init/exit layer, but since devices info is
  not per-device, but shared for the whole btrfs module, such break
  should still be acceptable.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/disk-io.c | 88 ++++++++++++++++++++++++++++------------------
 1 file changed, 53 insertions(+), 35 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 4fcdd15697d0..e03927cb00b8 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3634,6 +3634,56 @@ static void open_ctree_chunk_tree_exit(struct btrfs_fs_info *fs_info)
 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
 }
 
+static int open_ctree_tree_roots_init(struct btrfs_fs_info *fs_info)
+{
+	int ret;
+
+	ret = init_tree_roots(fs_info);
+	if (ret)
+		goto error;
+
+	/*
+	 * Get zone type information of zoned block devices. This will also
+	 * handle emulation of a zoned filesystem if a regular device has the
+	 * zoned incompat feature flag set.
+	 */
+	ret = btrfs_get_dev_zone_info_all_devices(fs_info);
+	if (ret) {
+		btrfs_err(fs_info,
+			  "zoned: failed to read device zone info: %d",
+			  ret);
+		goto error;
+	}
+
+	/*
+	 * If we have a uuid root and we're not being told to rescan we need to
+	 * check the generation here so we can set the
+	 * BTRFS_FS_UPDATE_UUID_TREE_GEN bit.  Otherwise we could commit the
+	 * transaction during a balance or the log replay without updating the
+	 * uuid generation, and then if we crash we would rescan the uuid tree,
+	 * even though it was perfectly fine.
+	 */
+	if (fs_info->uuid_root && !btrfs_test_opt(fs_info, RESCAN_UUID_TREE) &&
+	    fs_info->generation ==
+	    btrfs_super_uuid_tree_generation(fs_info->super_copy))
+		set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
+
+	return 0;
+
+error:
+	if (fs_info->data_reloc_root)
+		btrfs_drop_and_free_fs_root(fs_info, fs_info->data_reloc_root);
+	free_root_pointers(fs_info, true);
+	return ret;
+}
+
+static void open_ctree_tree_roots_exit(struct btrfs_fs_info *fs_info)
+{
+	if (fs_info->data_reloc_root)
+		btrfs_drop_and_free_fs_root(fs_info, fs_info->data_reloc_root);
+	free_root_pointers(fs_info, true);
+}
+
 struct init_sequence {
 	int (*init_func)(struct btrfs_fs_info *fs_info);
 	void (*exit_func)(struct btrfs_fs_info *fs_info);
@@ -3655,6 +3705,9 @@ static const struct init_sequence open_ctree_seq[] = {
 	}, {
 		.init_func = open_ctree_chunk_tree_init,
 		.exit_func = open_ctree_chunk_tree_exit,
+	}, {
+		.init_func = open_ctree_tree_roots_init,
+		.exit_func = open_ctree_tree_roots_exit,
 	}
 };
 
@@ -3680,36 +3733,6 @@ int __cold open_ctree(struct super_block *sb, char *options)
 		open_ctree_res[i] = true;
 	}
 
-	ret = init_tree_roots(fs_info);
-	if (ret)
-		goto fail_tree_roots;
-
-	/*
-	 * Get zone type information of zoned block devices. This will also
-	 * handle emulation of a zoned filesystem if a regular device has the
-	 * zoned incompat feature flag set.
-	 */
-	ret = btrfs_get_dev_zone_info_all_devices(fs_info);
-	if (ret) {
-		btrfs_err(fs_info,
-			  "zoned: failed to read device zone info: %d",
-			  ret);
-		goto fail_block_groups;
-	}
-
-	/*
-	 * If we have a uuid root and we're not being told to rescan we need to
-	 * check the generation here so we can set the
-	 * BTRFS_FS_UPDATE_UUID_TREE_GEN bit.  Otherwise we could commit the
-	 * transaction during a balance or the log replay without updating the
-	 * uuid generation, and then if we crash we would rescan the uuid tree,
-	 * even though it was perfectly fine.
-	 */
-	if (fs_info->uuid_root && !btrfs_test_opt(fs_info, RESCAN_UUID_TREE) &&
-	    fs_info->generation ==
-	    btrfs_super_uuid_tree_generation(fs_info->super_copy))
-		set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
-
 	ret = btrfs_verify_dev_extents(fs_info);
 	if (ret) {
 		btrfs_err(fs_info,
@@ -3869,11 +3892,6 @@ int __cold open_ctree(struct super_block *sb, char *options)
 
 fail_block_groups:
 	btrfs_put_block_group_cache(fs_info);
-
-fail_tree_roots:
-	if (fs_info->data_reloc_root)
-		btrfs_drop_and_free_fs_root(fs_info, fs_info->data_reloc_root);
-	free_root_pointers(fs_info, true);
 	btrfs_free_block_groups(fs_info);
 fail:
 	for (i = ARRAY_SIZE(open_ctree_seq) - 1; i >= 0; i--) {
-- 
2.37.3