Ext2: use unlikely to improve the efficiency of the kernel

Because the function 'sb_getblk' seldomly fails to return
NULL value. It will be better to use unlikely to optimize it.

Signed-off-by: Wang shilong <[e-mail]>
Signed-off-by: Jan Kara <[e-mail]>

fs/ext2/super.c

···
 			bh = sb_bread(sb, tmp_bh.b_blocknr);
 		else
 			bh = sb_getblk(sb, tmp_bh.b_blocknr);
-		if (!bh) {
+		if (unlikely(!bh)) {
 			err = -EIO;
 			goto out;
 		}

fs/ext2/xattr.c

···
 			ea_idebug(inode, "creating block %d", block);
 
 			new_bh = sb_getblk(sb, block);
-			if (!new_bh) {
+			if (unlikely(!new_bh)) {
 				ext2_free_blocks(inode, block, 1);
 				mark_inode_dirty(inode);
 				error = -EIO;