nilfs2: do not return io error for bio allocation failure

Previously, log writer had possibility to set an io error flag on
segments even in case of memory allocation failure.

This fixes the issue.
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

fs/nilfs2/segbuf.c

@@ -374,7 +374,7 @@ int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 		       struct nilfs_write_info *wi)
 {
 	struct buffer_head *bh;
-	int res, rw = WRITE;
+	int res = 0, rw = WRITE;
 
 	list_for_each_entry(bh, &segbuf->sb_segsum_buffers, b_assoc_buffers) {
 		res = nilfs_submit_bh(wi, bh, rw);
@@ -395,17 +395,10 @@ int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
 		 */
 		rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG);
 		res = nilfs_submit_seg_bio(wi, rw);
-		if (unlikely(res))
-			goto failed_bio;
 	}
 
-	res = 0;
- out:
-	return res;
-
  failed_bio:
-	atomic_inc(&wi->err);
-	goto out;
+	return res;
 }
 
 /**