btrfs-progs: remove block group free space

In the upstream equivalent of btrfs_remove_block_group(), the
function remove_block_group_free_space() is called to delete free
spaces associated with the block group being freed. However, this
function is defined in btrfs-progs but not called anywhere.

To address this issue, I added a call to
remove_block_group_free_space() in btrfs_remove_block_group(). This
ensures that the free spaces are properly deleted when a block group
is removed.

I also added a check to remove_block_group_free_space to make sure that
free-space-tree is enabled.

Signed-off-by: Leo Martins <loemra.dev@gmail.com>

Author: loemraw

kernel-shared/extent-tree.c

@@ -3506,6 +3506,16 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 		return ret;
 	}
 
+	/* delete free space items associated with this block group */
+	ret = remove_block_group_free_space(trans, block_group);
+	if (ret < 0) {
+		fprintf(stderr,
+			"failed to remove free space associated with block group for [%llu,%llu)\n",
+			bytenr, bytenr + len);
+		btrfs_unpin_extent(fs_info, bytenr, len);
+		return ret;
+	}
+
 	/* Now release the block_group_cache */
 	ret = free_block_group_cache(trans, fs_info, bytenr, len);
 	btrfs_unpin_extent(fs_info, bytenr, len);

kernel-shared/free-space-tree.c

@@ -1171,6 +1171,9 @@ int remove_block_group_free_space(struct btrfs_trans_handle *trans,
 	int done = 0, nr;
 	int ret;
 
+	if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
+		return 0;
+
 	path = btrfs_alloc_path();
 	if (!path) {
 		ret = -ENOMEM;