btrfs: add WARN_ON() to check is space_info op current

space_info's value calculation is some complex and easy to cause
bug, add WARN_ON() to help debug.

Changelog v1->v2:
 Put WARN_ON()s under the ENOSPC_DEBUG mount option.
 Suggested by: David Sterba <dsterba@suse.cz>

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7a14a4aa50a7..be4a79a69ed1 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -9732,9 +9732,19 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 
         spin_lock(&block_group->space_info->lock);
         list_del_init(&block_group->ro_list);
+
+        if (btrfs_test_opt(root, ENOSPC_DEBUG)) {
+                WARN_ON(block_group->space_info->total_bytes
+                        < block_group->key.offset);
+                WARN_ON(block_group->space_info->bytes_readonly
+                        < block_group->key.offset);
+                WARN_ON(block_group->space_info->disk_total
+                        < block_group->key.offset * factor);
+        }
         block_group->space_info->total_bytes -= block_group->key.offset;
         block_group->space_info->bytes_readonly -= block_group->key.offset;
         block_group->space_info->disk_total -= block_group->key.offset * factor;
+
         spin_unlock(&block_group->space_info->lock);
 
         memcpy(&key, &block_group->key, sizeof(key));