Btrfs: lzo: compressed data size must be less then input size

Logic already skips if compression makes data bigger, let's sync lzo
with zlib and also return error if compressed size is equal to
input size.

Signed-off-by: Timofey Titovets <nefelim4ag@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/lzo.c

@@ -230,8 +230,10 @@ static int lzo_compress_pages(struct list_head *ws,
 		in_len = min(bytes_left, PAGE_SIZE);
 	}
 
-	if (tot_out > tot_in)
+	if (tot_out >= tot_in) {
+		ret = -E2BIG;
 		goto out;
+	}
 
 	/* store the size of all chunks of compressed data */
 	cpage_out = kmap(pages[0]);