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>

fs/ext2/balloc.c

@@ -568,8 +568,11 @@ void ext2_free_blocks (struct inode * inode, unsigned long block,
 	}
 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 @@ ext2_fsblk_t ext2_new_blocks(struct inode *inode, ext2_fsblk_t goal,
 
 	*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: