bcachefs: KEY_TYPE_error now counts towards i_sectors

KEY_TYPE_error is used when all replicas in an extent are marked as
failed; it indicates that data was present, but has been lost.

So that i_sectors doesn't change when replacing extents with
KEY_TYPE_error, we now have to count error keys as allocations - this
fixes fsck errors later.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/extents.h

@@ -520,6 +520,7 @@ static inline bool bkey_extent_is_allocation(const struct bkey *k)
 	case KEY_TYPE_reflink_v:
 	case KEY_TYPE_inline_data:
 	case KEY_TYPE_indirect_inline_data:
+	case KEY_TYPE_error:
 		return true;
 	default:
 		return false;