diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 3b9740c1c16d..7a0dadf6c5fe 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -83,6 +83,25 @@ static struct buffer_head *ext4_append(handle_t *handle,
 	bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
 	if (IS_ERR(bh))
 		return bh;
+
+	for (map.m_lblk = 0; map.m_lblk < *block; map.m_lblk += map.m_len) {
+		map.m_len = *block - map.m_lblk;
+		err = ext4_map_blocks(NULL, inode, &map, 0);
+		if (err < 0) {
+			brelse(bh);
+			return ERR_PTR(err);
+		}
+		if (err > 0 && bh->b_blocknr - map.m_pblk < map.m_len) {
+			EXT4_ERROR_INODE(inode,
+					 "new block %llu already mapped",
+					 (unsigned long long)bh->b_blocknr);
+			brelse(bh);
+			return ERR_PTR(-EFSCORRUPTED);
+		}
+		if (map.m_len < 1)
+			map.m_len = 1;
+	}
+
 	inode->i_size += inode->i_sb->s_blocksize;
 	EXT4_I(inode)->i_disksize = inode->i_size;
 	err = ext4_mark_inode_dirty(handle, inode);