diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 3ae4a38..097f9c4 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -1457,21 +1457,16 @@
 					  struct inode *sufile)
 {
 	struct nilfs_segment_buffer *segbuf;
-	struct buffer_head *bh_su;
-	struct nilfs_segment_usage *raw_su;
 	unsigned long live_blocks;
 	int ret;
 
 	list_for_each_entry(segbuf, &sci->sc_segbufs, sb_list) {
-		ret = nilfs_sufile_get_segment_usage(sufile, segbuf->sb_segnum,
-						     &raw_su, &bh_su);
-		WARN_ON(ret); /* always succeed because bh_su is dirty */
 		live_blocks = segbuf->sb_sum.nblocks +
 			(segbuf->sb_pseg_start - segbuf->sb_fseg_start);
-		raw_su->su_lastmod = cpu_to_le64(sci->sc_seg_ctime);
-		raw_su->su_nblocks = cpu_to_le32(live_blocks);
-		nilfs_sufile_put_segment_usage(sufile, segbuf->sb_segnum,
-					       bh_su);
+		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
+						     live_blocks,
+						     sci->sc_seg_ctime);
+		WARN_ON(ret); /* always succeed because the segusage is dirty */
 	}
 }
 
@@ -1479,25 +1474,18 @@
 					  struct inode *sufile)
 {
 	struct nilfs_segment_buffer *segbuf;
-	struct buffer_head *bh_su;
-	struct nilfs_segment_usage *raw_su;
 	int ret;
 
 	segbuf = NILFS_FIRST_SEGBUF(&sci->sc_segbufs);
-	ret = nilfs_sufile_get_segment_usage(sufile, segbuf->sb_segnum,
-					     &raw_su, &bh_su);
-	WARN_ON(ret); /* always succeed because bh_su is dirty */
-	raw_su->su_nblocks = cpu_to_le32(segbuf->sb_pseg_start -
-					 segbuf->sb_fseg_start);
-	nilfs_sufile_put_segment_usage(sufile, segbuf->sb_segnum, bh_su);
+	ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
+					     segbuf->sb_pseg_start -
+					     segbuf->sb_fseg_start, 0);
+	WARN_ON(ret); /* always succeed because the segusage is dirty */
 
 	list_for_each_entry_continue(segbuf, &sci->sc_segbufs, sb_list) {
-		ret = nilfs_sufile_get_segment_usage(sufile, segbuf->sb_segnum,
-						     &raw_su, &bh_su);
+		ret = nilfs_sufile_set_segment_usage(sufile, segbuf->sb_segnum,
+						     0, 0);
 		WARN_ON(ret); /* always succeed */
-		raw_su->su_nblocks = 0;
-		nilfs_sufile_put_segment_usage(sufile, segbuf->sb_segnum,
-					       bh_su);
 	}
 }
 
diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
index d560f882..3eed998 100644
--- a/fs/nilfs2/sufile.c
+++ b/fs/nilfs2/sufile.c
@@ -521,6 +521,43 @@
 }
 
 /**
+ * nilfs_sufile_set_segment_usage - set usage of a segment
+ * @sufile: inode of segment usage file
+ * @segnum: segment number
+ * @nblocks: number of live blocks in the segment
+ * @modtime: modification time (option)
+ */
+int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
+				   unsigned long nblocks, time_t modtime)
+{
+	struct buffer_head *bh;
+	struct nilfs_segment_usage *su;
+	void *kaddr;
+	int ret;
+
+	down_write(&NILFS_MDT(sufile)->mi_sem);
+	ret = nilfs_sufile_get_segment_usage_block(sufile, segnum, 0, &bh);
+	if (ret < 0)
+		goto out_sem;
+
+	kaddr = kmap_atomic(bh->b_page, KM_USER0);
+	su = nilfs_sufile_block_get_segment_usage(sufile, segnum, bh, kaddr);
+	WARN_ON(nilfs_segment_usage_error(su));
+	if (modtime)
+		su->su_lastmod = cpu_to_le64(modtime);
+	su->su_nblocks = cpu_to_le32(nblocks);
+	kunmap_atomic(kaddr, KM_USER0);
+
+	nilfs_mdt_mark_buffer_dirty(bh);
+	nilfs_mdt_mark_dirty(sufile);
+	brelse(bh);
+
+ out_sem:
+	up_write(&NILFS_MDT(sufile)->mi_sem);
+	return ret;
+}
+
+/**
  * nilfs_sufile_get_stat - get segment usage statistics
  * @sufile: inode of segment usage file
  * @stat: pointer to a structure of segment usage statistics
diff --git a/fs/nilfs2/sufile.h b/fs/nilfs2/sufile.h
index 4146a65..e1186bf 100644
--- a/fs/nilfs2/sufile.h
+++ b/fs/nilfs2/sufile.h
@@ -43,6 +43,8 @@
 void nilfs_sufile_put_segment_usage(struct inode *, __u64,
 				    struct buffer_head *);
 int nilfs_sufile_mark_dirty(struct inode *sufile, __u64 segnum);
+int nilfs_sufile_set_segment_usage(struct inode *sufile, __u64 segnum,
+				   unsigned long nblocks, time_t modtime);
 int nilfs_sufile_get_stat(struct inode *, struct nilfs_sustat *);
 ssize_t nilfs_sufile_get_suinfo(struct inode *, __u64, void *, unsigned,
 				size_t);