f2fs: send REQ_META or REQ_PRIO when reading meta area

Let's send REQ_META or REQ_PRIO when reading meta area such as NAT/SIT
etc.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/checkpoint.c

@@ -61,7 +61,7 @@ repeat:
 	if (PageUptodate(page))
 		goto out;
 
-	if (f2fs_readpage(sbi, page, index, READ_SYNC))
+	if (f2fs_readpage(sbi, page, index, READ_SYNC | REQ_META | REQ_PRIO))
 		goto repeat;
 
 	lock_page(page);

fs/f2fs/node.c

@@ -106,11 +106,11 @@ static void ra_nat_pages(struct f2fs_sb_info *sbi, int nid)
 			f2fs_put_page(page, 1);
 			continue;
 		}
-		submit_read_page(sbi, page, index, READ_SYNC);
+		submit_read_page(sbi, page, index, READ_SYNC | REQ_META);
 		mark_page_accessed(page);
 		f2fs_put_page(page, 0);
 	}
-	f2fs_submit_read_bio(sbi, READ_SYNC);
+	f2fs_submit_read_bio(sbi, READ_SYNC | REQ_META);
 }
 
 static struct nat_entry *__lookup_nat_cache(struct f2fs_nm_info *nm_i, nid_t n)

fs/f2fs/segment.c

@@ -1734,13 +1734,13 @@ repeat:
 			continue;
 		}
 
-		submit_read_page(sbi, page, blk_addr, READ_SYNC);
+		submit_read_page(sbi, page, blk_addr, READ_SYNC | REQ_META);
 
 		mark_page_accessed(page);
 		f2fs_put_page(page, 0);
 	}
 
-	f2fs_submit_read_bio(sbi, READ_SYNC);
+	f2fs_submit_read_bio(sbi, READ_SYNC | REQ_META);
 	return blkno - start;
 }