+/*
+ * Try to flush truncate logs if we can free enough clusters from it.
+ * As for return value, "< 0" means error, "0" no space and "1" means
+ * we have freed enough spaces and let the caller try to allocate again.
+ */
+static int ocfs2_try_to_free_truncate_log(struct ocfs2_super *osb,
+ unsigned int needed)
+{
+ tid_t target;
+ int ret = 0;
+ unsigned int truncated_clusters;
+
+ mutex_lock(&osb->osb_tl_inode->i_mutex);
+ truncated_clusters = osb->truncated_clusters;
+ mutex_unlock(&osb->osb_tl_inode->i_mutex);
+
+ /*
+ * Check whether we can succeed in allocating if we free
+ * the truncate log.
+ */
+ if (truncated_clusters < needed)
+ goto out;
+
+ ret = ocfs2_flush_truncate_log(osb);
+ if (ret) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+ if (jbd2_journal_start_commit(osb->journal->j_journal, &target)) {
+ jbd2_log_wait_commit(osb->journal->j_journal, target);
+ ret = 1;
+ }
+out:
+ return ret;
+}
+