Write mount points for inodes that were not found.

This allows us to at least know which partition inodes were
on even if we cannot find any of them.

Bug: 73625480
Change-Id: I12e807d4cfa535a590a9aefe672d255ed059ce4e

2 files changed, 10 insertions, 0 deletions

diff --git a/src/traced/probes/filesystem/inode_file_data_source.cc b/src/traced/probes/filesystem/inode_file_data_source.cc
index a66c2a9c9..dac9bf1eb 100644
--- a/src/traced/probes/filesystem/inode_file_data_source.cc
+++ b/src/traced/probes/filesystem/inode_file_data_source.cc
@@ -250,6 +250,7 @@ void InodeFileDataSource::OnInodes(
 
 InodeFileMap* InodeFileDataSource::AddToCurrentTracePacket(
     BlockDeviceID block_device_id) {
+  seen_block_devices_.emplace(block_device_id);
   if (!has_current_trace_packet_ ||
       current_block_device_id_ != block_device_id) {
     if (has_current_trace_packet_)
@@ -325,6 +326,14 @@ void InodeFileDataSource::OnInodeScanDone() {
   // Finalize the accumulated trace packets.
   ResetTracePacket();
   file_scanner_.reset();
+  if (!missing_inodes_.empty()) {
+    // At least write mount point mapping for inodes that are not found.
+    for (const auto& p : missing_inodes_) {
+      if (seen_block_devices_.count(p.first) == 0)
+        AddToCurrentTracePacket(p.first);
+    }
+  }
+
   if (next_missing_inodes_.empty()) {
     scan_running_ = false;
   } else {
diff --git a/src/traced/probes/filesystem/inode_file_data_source.h b/src/traced/probes/filesystem/inode_file_data_source.h
index bede1240d..926031cf3 100644
--- a/src/traced/probes/filesystem/inode_file_data_source.h
+++ b/src/traced/probes/filesystem/inode_file_data_source.h
@@ -118,6 +118,7 @@ class InodeFileDataSource : public FileScanner::Delegate {
   std::unique_ptr<TraceWriter> writer_;
   std::map<BlockDeviceID, std::set<Inode>> missing_inodes_;
   std::map<BlockDeviceID, std::set<Inode>> next_missing_inodes_;
+  std::set<BlockDeviceID> seen_block_devices_;
   BlockDeviceID current_block_device_id_;
   TraceWriter::TracePacketHandle current_trace_packet_;
   InodeFileMap* current_file_map_;