diff --git a/include/crucible/fs.h b/include/crucible/fs.h
index c0bfef5..d208cca 100644
--- a/include/crucible/fs.h
+++ b/include/crucible/fs.h
@@ -13,6 +13,7 @@
 
 #include <cstdint>
 #include <iosfwd>
+#include <set>
 #include <vector>
 
 #include <fcntl.h>
@@ -150,6 +151,7 @@ namespace crucible {
 		BtrfsIoctlSearchHeader();
 		vector<char> m_data;
 		size_t set_data(const vector<char> &v, size_t offset);
+		bool operator<(const BtrfsIoctlSearchHeader &that) const;
 	};
 
 	ostream & operator<<(ostream &os, const btrfs_ioctl_search_header &hdr);
@@ -164,7 +166,8 @@ namespace crucible {
 		void next_min(const BtrfsIoctlSearchHeader& ref);
 
 		size_t m_buf_size;
-		vector<BtrfsIoctlSearchHeader> m_result;
+		set<BtrfsIoctlSearchHeader> m_result;
+
 	};
 
 	ostream & operator<<(ostream &os, const btrfs_ioctl_search_key &key);
diff --git a/lib/fs.cc b/lib/fs.cc
index 16e5649..9f6d4b7 100644
--- a/lib/fs.cc
+++ b/lib/fs.cc
@@ -707,6 +707,12 @@ namespace crucible {
 		return offset + len;
 	}
 
+	bool
+	BtrfsIoctlSearchHeader::operator<(const BtrfsIoctlSearchHeader &that) const
+	{
+		return tie(objectid, type, offset, len, transid) < tie(that.objectid, that.type, that.offset, that.len, that.transid);
+	}
+
 	bool
 	BtrfsIoctlSearchKey::do_ioctl_nothrow(int fd)
 	{
@@ -727,13 +733,12 @@ namespace crucible {
 		static_cast<btrfs_ioctl_search_key&>(*this) = ioctl_ptr->key;
 
 		m_result.clear();
-		m_result.reserve(nr_items);
 
 		size_t offset = pointer_distance(ioctl_ptr->buf, ioctl_ptr);
 		for (decltype(nr_items) i = 0; i < nr_items; ++i) {
 			BtrfsIoctlSearchHeader item;
 			offset = item.set_data(ioctl_arg, offset);
-			m_result.push_back(item);
+			m_result.insert(item);
 		}
 
 		return true;