Ext2: mark inode dirty after the function dquot_free_block_nodirty is called

We should mark inode dirty after the function dquot_free_block_nodirty
is called.Besides,add a check whether it is necessary to call
dquot_free_block_nodirty functon.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index ea88181..132da4c 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -568,8 +568,11 @@
 	}
 error_return:
 	brelse(bitmap_bh);
-	release_blocks(sb, freed);
-	dquot_free_block_nodirty(inode, freed);
+	if (freed) {
+		release_blocks(sb, freed);
+		dquot_free_block_nodirty(inode, freed);
+		mark_inode_dirty(inode);
+	}
 }
 
 /**
@@ -1412,9 +1415,11 @@
 
 	*errp = 0;
 	brelse(bitmap_bh);
-	dquot_free_block_nodirty(inode, *count-num);
-	mark_inode_dirty(inode);
-	*count = num;
+	if (num < *count) {
+		dquot_free_block_nodirty(inode, *count-num);
+		mark_inode_dirty(inode);
+		*count = num;
+	}
 	return ret_block;
 
 io_error: