diff --git a/fs/smb/client/cifsfs.c b/fs/smb/client/cifsfs.c
index 7ecd70efdfea..f1fb4b7b7b7c 100644
--- a/fs/smb/client/cifsfs.c
+++ b/fs/smb/client/cifsfs.c
@@ -1581,8 +1581,13 @@ ssize_t cifs_file_copychunk_range(unsigned int xid,
 	/* Flush and invalidate all the folios in the destination region.  If
 	 * the copy was successful, then some of the flush is extra overhead,
 	 * but we need to allow for the copy failing in some way (eg. ENOSPC).
+	 *
+	 * Start at the old EOF when extending so the folio straddling it, which
+	 * may hold data written past EOF through an mmap, is dropped too.
 	 */
-	rc = filemap_invalidate_inode(target_inode, true, destoff, destoff + len - 1);
+	rc = filemap_invalidate_inode(target_inode, true,
+				      min(destoff, i_size_read(target_inode)),
+				      destoff + len - 1);
 	if (rc)
 		goto unlock;