ocfs2: fix the la space leak when unmounting an ocfs2 volume

This bug has existed since the initial OCFS2 code.  The code logic in
ocfs2_sync_local_to_main() is wrong, as it ignores the last contiguous
free bits, which causes an OCFS2 volume to lose the last free clusters of
LA window on each umount command.

Link: https://lkml.kernel.org/r/20240719114310.14245-1-heming.zhao@suse.comSigned-off-by: Heming Zhao <heming.zhao@suse.com>
Reviewed-by: Su Yue <glass.su@suse.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Cc: Heming Zhao <heming.zhao@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/ocfs2/localalloc.c

@@ -1002,6 +1002,25 @@ static int ocfs2_sync_local_to_main(struct ocfs2_super *osb,
 		start = bit_off + 1;
 	}
 
+	/* clear the contiguous bits until the end boundary */
+	if (count) {
+		blkno = la_start_blk +
+			ocfs2_clusters_to_blocks(osb->sb,
+					start - count);
+
+		trace_ocfs2_sync_local_to_main_free(
+				count, start - count,
+				(unsigned long long)la_start_blk,
+				(unsigned long long)blkno);
+
+		status = ocfs2_release_clusters(handle,
+				main_bm_inode,
+				main_bm_bh, blkno,
+				count);
+		if (status < 0)
+			mlog_errno(status);
+	}
+
 bail:
 	if (status)
 		mlog_errno(status);