src/traced/probes/filesystem/inode_file_data_source.cc - third_party/perfetto - Git at Google

 /*
  * Copyright (C) 2018 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include "src/traced/probes/filesystem/inode_file_data_source.h"

 #include <dirent.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <queue>
 #include <unordered_map>

 #include "perfetto/base/logging.h"
 #include "perfetto/ext/base/scoped_file.h"
 #include "perfetto/ext/tracing/core/trace_packet.h"
 #include "perfetto/ext/tracing/core/trace_writer.h"

 #include "protos/perfetto/config/inode_file/inode_file_config.pbzero.h"
 #include "protos/perfetto/trace/filesystem/inode_file_map.pbzero.h"
 #include "protos/perfetto/trace/trace_packet.pbzero.h"
 #include "src/traced/probes/filesystem/file_scanner.h"

 namespace perfetto {
 namespace {
 constexpr uint32_t kScanIntervalMs = 10000;  // 10s
 constexpr uint32_t kScanDelayMs = 10000;     // 10s
 constexpr uint32_t kScanBatchSize = 15000;

 uint32_t OrDefault(uint32_t value, uint32_t def) {
   return value ? value : def;
 }

 std::string DbgFmt(const std::vector<std::string>& values) {
   if (values.empty())
     return "";

   std::string result;
   for (auto it = values.cbegin(); it != values.cend() - 1; ++it)
     result += *it + ",";

   result += values.back();
   return result;
 }

 class StaticMapDelegate : public FileScanner::Delegate {
  public:
   StaticMapDelegate(
       std::map<BlockDeviceID, std::unordered_map<Inode, InodeMapValue>>* map)
       : map_(map) {}
   ~StaticMapDelegate() override {}

  private:
   bool OnInodeFound(BlockDeviceID block_device_id,
                     Inode inode_number,
                     const std::string& path,
                     InodeFileMap_Entry_Type type) override {
     std::unordered_map<Inode, InodeMapValue>& inode_map =
         (*map_)[block_device_id];
     inode_map[inode_number].SetType(type);
     inode_map[inode_number].AddPath(path);
     return true;
   }
   void OnInodeScanDone() override {}
   std::map<BlockDeviceID, std::unordered_map<Inode, InodeMapValue>>* map_;
 };

 }  // namespace

 // static
 const ProbesDataSource::Descriptor InodeFileDataSource::descriptor = {
     /*name*/ "linux.inode_file_map",
     /*flags*/ Descriptor::kFlagsNone,
     /*fill_descriptor_func*/ nullptr,
 };

 void CreateStaticDeviceToInodeMap(
     const std::string& root_directory,
     std::map<BlockDeviceID, std::unordered_map<Inode, InodeMapValue>>*
         static_file_map) {
   StaticMapDelegate delegate(static_file_map);
   FileScanner scanner({root_directory}, &delegate);
   scanner.Scan();
 }

 void InodeFileDataSource::FillInodeEntry(InodeFileMap* destination,
                                          Inode inode_number,
                                          const InodeMapValue& inode_map_value) {
   auto* entry = destination->add_entries();
   entry->set_inode_number(inode_number);
   entry->set_type(static_cast<protos::pbzero::InodeFileMap_Entry_Type>(
       inode_map_value.type()));
   for (const auto& path : inode_map_value.paths())
     entry->add_paths(path.c_str());
 }

 InodeFileDataSource::InodeFileDataSource(
     const DataSourceConfig& ds_config,
     base::TaskRunner* task_runner,
     TracingSessionID session_id,
     std::map<BlockDeviceID, std::unordered_map<Inode, InodeMapValue>>*
         static_file_map,
     LRUInodeCache* cache,
     std::unique_ptr<TraceWriter> writer)
     : ProbesDataSource(session_id, &descriptor),
       task_runner_(task_runner),
       static_file_map_(static_file_map),
       cache_(cache),
       writer_(std::move(writer)),
       weak_factory_(this) {
   using protos::pbzero::InodeFileConfig;
   InodeFileConfig::Decoder cfg(ds_config.inode_file_config_raw());
   for (auto mp = cfg.scan_mount_points(); mp; ++mp)
     scan_mount_points_.insert((*mp).ToStdString());
   for (auto mpm = cfg.mount_point_mapping(); mpm; ++mpm) {
     InodeFileConfig::MountPointMappingEntry::Decoder entry(*mpm);
     std::vector<std::string> scan_roots;
     for (auto scan_root = entry.scan_roots(); scan_root; ++scan_root)
       scan_roots.push_back((*scan_root).ToStdString());
     std::string mountpoint = entry.mountpoint().ToStdString();
     mount_point_mapping_.emplace(mountpoint, std::move(scan_roots));
   }
   scan_interval_ms_ = OrDefault(cfg.scan_interval_ms(), kScanIntervalMs);
   scan_delay_ms_ = OrDefault(cfg.scan_delay_ms(), kScanDelayMs);
   scan_batch_size_ = OrDefault(cfg.scan_batch_size(), kScanBatchSize);
   do_not_scan_ = cfg.do_not_scan();
 }

 InodeFileDataSource::~InodeFileDataSource() = default;

 void InodeFileDataSource::Start() {
   // Nothing special to do, this data source is only reacting to on-demand
   // events such as OnInodes().
 }

 void InodeFileDataSource::AddInodesFromStaticMap(
     BlockDeviceID block_device_id,
     std::set<Inode>* inode_numbers) {
   // Check if block device id exists in static file map
   auto static_map_entry = static_file_map_->find(block_device_id);
   if (static_map_entry == static_file_map_->end())
     return;

   uint64_t system_found_count = 0;
   for (auto it = inode_numbers->begin(); it != inode_numbers->end();) {
     Inode inode_number = *it;
     // Check if inode number exists in static file map for given block device id
     auto inode_it = static_map_entry->second.find(inode_number);
     if (inode_it == static_map_entry->second.end()) {
       ++it;
       continue;
     }
     system_found_count++;
     it = inode_numbers->erase(it);
     FillInodeEntry(AddToCurrentTracePacket(block_device_id), inode_number,
                    inode_it->second);
   }
   PERFETTO_DLOG("%" PRIu64 " inodes found in static file map",
                 system_found_count);
 }

 void InodeFileDataSource::AddInodesFromLRUCache(
     BlockDeviceID block_device_id,
     std::set<Inode>* inode_numbers) {
   uint64_t cache_found_count = 0;
   for (auto it = inode_numbers->begin(); it != inode_numbers->end();) {
     Inode inode_number = *it;
     auto value = cache_->Get(std::make_pair(block_device_id, inode_number));
     if (value == nullptr) {
       ++it;
       continue;
     }
     cache_found_count++;
     it = inode_numbers->erase(it);
     FillInodeEntry(AddToCurrentTracePacket(block_device_id), inode_number,
                    *value);
   }
   if (cache_found_count > 0)
     PERFETTO_DLOG("%" PRIu64 " inodes found in cache", cache_found_count);
 }

 void InodeFileDataSource::Flush(FlushRequestID,
                                 std::function<void()> callback) {
   ResetTracePacket();
   writer_->Flush(callback);
 }

 void InodeFileDataSource::OnInodes(
     const base::FlatSet<InodeBlockPair>& inodes) {
   if (mount_points_.empty()) {
     mount_points_ = ParseMounts();
   }
   // Group inodes from FtraceMetadata by block device
   std::map<BlockDeviceID, std::set<Inode>> inode_file_maps;
   for (const auto& inodes_pair : inodes) {
     Inode inode_number = inodes_pair.first;
     BlockDeviceID block_device_id = inodes_pair.second;
     inode_file_maps[block_device_id].emplace(inode_number);
   }
   if (inode_file_maps.size() > 1)
     PERFETTO_DLOG("Saw %zu block devices.", inode_file_maps.size());

   // Write a TracePacket with an InodeFileMap proto for each block device id
   for (auto& inode_file_map_data : inode_file_maps) {
     BlockDeviceID block_device_id = inode_file_map_data.first;
     std::set<Inode>& inode_numbers = inode_file_map_data.second;
     PERFETTO_DLOG("Saw %zu unique inode numbers.", inode_numbers.size());

     // Add entries to InodeFileMap as inodes are found and resolved to their
     // paths/type
     AddInodesFromStaticMap(block_device_id, &inode_numbers);
     AddInodesFromLRUCache(block_device_id, &inode_numbers);

     if (do_not_scan_)
       inode_numbers.clear();

     // If we defined mount points we want to scan in the config,
     // skip inodes on other mount points.
     if (!scan_mount_points_.empty()) {
       bool process = true;
       auto range = mount_points_.equal_range(block_device_id);
       for (auto it = range.first; it != range.second; ++it) {
         if (scan_mount_points_.count(it->second) == 0) {
           process = false;
           break;
         }
       }
       if (!process)
         continue;
     }

     if (!inode_numbers.empty()) {
       // Try to piggy back the current scan.
       auto it = missing_inodes_.find(block_device_id);
       if (it != missing_inodes_.end()) {
         it->second.insert(inode_numbers.cbegin(), inode_numbers.cend());
       }
       next_missing_inodes_[block_device_id].insert(inode_numbers.cbegin(),
                                                    inode_numbers.cend());
       if (!scan_running_) {
         scan_running_ = true;
         auto weak_this = GetWeakPtr();
         task_runner_->PostDelayedTask(
             [weak_this] {
               if (!weak_this) {
                 PERFETTO_DLOG("Giving up filesystem scan.");
                 return;
               }
               weak_this->FindMissingInodes();
             },
             scan_delay_ms_);
       }
     }
   }
 }

 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_)
       current_trace_packet_->Finalize();
     current_trace_packet_ = writer_->NewTracePacket();
     current_file_map_ = current_trace_packet_->set_inode_file_map();
     has_current_trace_packet_ = true;

     // Add block device id to InodeFileMap
     current_file_map_->set_block_device_id(
         static_cast<uint64_t>(block_device_id));
     // Add mount points to InodeFileMap
     auto range = mount_points_.equal_range(block_device_id);
     for (std::multimap<BlockDeviceID, std::string>::iterator it = range.first;
          it != range.second; ++it)
       current_file_map_->add_mount_points(it->second.c_str());
   }
   return current_file_map_;
 }

 void InodeFileDataSource::RemoveFromNextMissingInodes(
     BlockDeviceID block_device_id,
     Inode inode_number) {
   auto it = next_missing_inodes_.find(block_device_id);
   if (it == next_missing_inodes_.end())
     return;
   it->second.erase(inode_number);
 }

 bool InodeFileDataSource::OnInodeFound(BlockDeviceID block_device_id,
                                        Inode inode_number,
                                        const std::string& path,
                                        InodeFileMap_Entry_Type inode_type) {
   auto it = missing_inodes_.find(block_device_id);
   if (it == missing_inodes_.end())
     return true;

   size_t n = it->second.erase(inode_number);
   if (n == 0)
     return true;

   if (it->second.empty())
     missing_inodes_.erase(it);

   RemoveFromNextMissingInodes(block_device_id, inode_number);

   std::pair<BlockDeviceID, Inode> key{block_device_id, inode_number};
   auto cur_val = cache_->Get(key);
   if (cur_val) {
     cur_val->AddPath(path);
     FillInodeEntry(AddToCurrentTracePacket(block_device_id), inode_number,
                    *cur_val);
   } else {
     InodeMapValue new_val(InodeMapValue(inode_type, {path}));
     cache_->Insert(key, new_val);
     FillInodeEntry(AddToCurrentTracePacket(block_device_id), inode_number,
                    new_val);
   }
   PERFETTO_DLOG("Filled %s", path.c_str());
   return !missing_inodes_.empty();
 }

 void InodeFileDataSource::ResetTracePacket() {
   current_block_device_id_ = 0;
   current_file_map_ = nullptr;
   if (has_current_trace_packet_)
     current_trace_packet_->Finalize();
   has_current_trace_packet_ = false;
 }

 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 {
     auto weak_this = GetWeakPtr();
     PERFETTO_DLOG("Starting another filesystem scan.");
     task_runner_->PostDelayedTask(
         [weak_this] {
           if (!weak_this) {
             PERFETTO_DLOG("Giving up filesystem scan.");
             return;
           }
           weak_this->FindMissingInodes();
         },
         scan_delay_ms_);
   }
 }

 void InodeFileDataSource::AddRootsForBlockDevice(
     BlockDeviceID block_device_id,
     std::vector<std::string>* roots) {
   auto range = mount_points_.equal_range(block_device_id);
   for (auto it = range.first; it != range.second; ++it) {
     PERFETTO_DLOG("Trying to replace %s", it->second.c_str());
     auto replace_it = mount_point_mapping_.find(it->second);
     if (replace_it != mount_point_mapping_.end()) {
       roots->insert(roots->end(), replace_it->second.cbegin(),
                     replace_it->second.cend());
       return;
     }
   }

   for (auto it = range.first; it != range.second; ++it)
     roots->emplace_back(it->second);
 }

 void InodeFileDataSource::FindMissingInodes() {
   missing_inodes_ = std::move(next_missing_inodes_);
   std::vector<std::string> roots;
   for (auto& p : missing_inodes_)
     AddRootsForBlockDevice(p.first, &roots);

   PERFETTO_DCHECK(file_scanner_.get() == nullptr);
   auto weak_this = GetWeakPtr();
   PERFETTO_DLOG("Starting scan of %s", DbgFmt(roots).c_str());
   file_scanner_ = std::unique_ptr<FileScanner>(new FileScanner(
       std::move(roots), this, scan_interval_ms_, scan_batch_size_));

   file_scanner_->Scan(task_runner_);
 }

 base::WeakPtr<InodeFileDataSource> InodeFileDataSource::GetWeakPtr() const {
   return weak_factory_.GetWeakPtr();
 }

 }  // namespace perfetto
	/*
	* Copyright (C) 2018 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include "src/traced/probes/filesystem/inode_file_data_source.h"

	#include <dirent.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <unistd.h>
	#include <queue>
	#include <unordered_map>

	#include "perfetto/base/logging.h"
	#include "perfetto/ext/base/scoped_file.h"
	#include "perfetto/ext/tracing/core/trace_packet.h"
	#include "perfetto/ext/tracing/core/trace_writer.h"

	#include "protos/perfetto/config/inode_file/inode_file_config.pbzero.h"
	#include "protos/perfetto/trace/filesystem/inode_file_map.pbzero.h"
	#include "protos/perfetto/trace/trace_packet.pbzero.h"
	#include "src/traced/probes/filesystem/file_scanner.h"

	namespace perfetto {
	namespace {
	constexpr uint32_t kScanIntervalMs = 10000; // 10s
	constexpr uint32_t kScanDelayMs = 10000; // 10s
	constexpr uint32_t kScanBatchSize = 15000;

	uint32_t OrDefault(uint32_t value, uint32_t def) {
	return value ? value : def;
	}

	std::string DbgFmt(const std::vector<std::string>& values) {
	if (values.empty())
	return "";

	std::string result;
	for (auto it = values.cbegin(); it != values.cend() - 1; ++it)
	result += *it + ",";

	result += values.back();
	return result;
	}

	class StaticMapDelegate : public FileScanner::Delegate {
	public:
	StaticMapDelegate(
	std::map<BlockDeviceID, std::unordered_map<Inode, InodeMapValue>>* map)
	: map_(map) {}
	~StaticMapDelegate() override {}

	private:
	bool OnInodeFound(BlockDeviceID block_device_id,
	Inode inode_number,
	const std::string& path,
	InodeFileMap_Entry_Type type) override {
	std::unordered_map<Inode, InodeMapValue>& inode_map =
	(*map_)[block_device_id];
	inode_map[inode_number].SetType(type);
	inode_map[inode_number].AddPath(path);
	return true;
	}
	void OnInodeScanDone() override {}
	std::map<BlockDeviceID, std::unordered_map<Inode, InodeMapValue>>* map_;
	};

	} // namespace

	// static
	const ProbesDataSource::Descriptor InodeFileDataSource::descriptor = {
	/name/ "linux.inode_file_map",
	/flags/ Descriptor::kFlagsNone,
	/fill_descriptor_func/ nullptr,
	};

	void CreateStaticDeviceToInodeMap(
	const std::string& root_directory,
	std::map<BlockDeviceID, std::unordered_map<Inode, InodeMapValue>>*
	static_file_map) {
	StaticMapDelegate delegate(static_file_map);
	FileScanner scanner({root_directory}, &delegate);
	scanner.Scan();
	}

	void InodeFileDataSource::FillInodeEntry(InodeFileMap* destination,
	Inode inode_number,
	const InodeMapValue& inode_map_value) {
	auto* entry = destination->add_entries();
	entry->set_inode_number(inode_number);
	entry->set_type(static_cast<protos::pbzero::InodeFileMap_Entry_Type>(
	inode_map_value.type()));
	for (const auto& path : inode_map_value.paths())
	entry->add_paths(path.c_str());
	}

	InodeFileDataSource::InodeFileDataSource(
	const DataSourceConfig& ds_config,
	base::TaskRunner* task_runner,
	TracingSessionID session_id,
	std::map<BlockDeviceID, std::unordered_map<Inode, InodeMapValue>>*
	static_file_map,
	LRUInodeCache* cache,
	std::unique_ptr<TraceWriter> writer)
	: ProbesDataSource(session_id, &descriptor),
	task_runner_(task_runner),
	static_file_map_(static_file_map),
	cache_(cache),
	writer_(std::move(writer)),
	weak_factory_(this) {
	using protos::pbzero::InodeFileConfig;
	InodeFileConfig::Decoder cfg(ds_config.inode_file_config_raw());
	for (auto mp = cfg.scan_mount_points(); mp; ++mp)
	scan_mount_points_.insert((*mp).ToStdString());
	for (auto mpm = cfg.mount_point_mapping(); mpm; ++mpm) {
	InodeFileConfig::MountPointMappingEntry::Decoder entry(*mpm);
	std::vector<std::string> scan_roots;
	for (auto scan_root = entry.scan_roots(); scan_root; ++scan_root)
	scan_roots.push_back((*scan_root).ToStdString());
	std::string mountpoint = entry.mountpoint().ToStdString();
	mount_point_mapping_.emplace(mountpoint, std::move(scan_roots));
	}
	scan_interval_ms_ = OrDefault(cfg.scan_interval_ms(), kScanIntervalMs);
	scan_delay_ms_ = OrDefault(cfg.scan_delay_ms(), kScanDelayMs);
	scan_batch_size_ = OrDefault(cfg.scan_batch_size(), kScanBatchSize);
	do_not_scan_ = cfg.do_not_scan();
	}

	InodeFileDataSource::~InodeFileDataSource() = default;

	void InodeFileDataSource::Start() {
	// Nothing special to do, this data source is only reacting to on-demand
	// events such as OnInodes().
	}

	void InodeFileDataSource::AddInodesFromStaticMap(
	BlockDeviceID block_device_id,
	std::set<Inode>* inode_numbers) {
	// Check if block device id exists in static file map
	auto static_map_entry = static_file_map_->find(block_device_id);
	if (static_map_entry == static_file_map_->end())
	return;

	uint64_t system_found_count = 0;
	for (auto it = inode_numbers->begin(); it != inode_numbers->end();) {
	Inode inode_number = *it;
	// Check if inode number exists in static file map for given block device id
	auto inode_it = static_map_entry->second.find(inode_number);
	if (inode_it == static_map_entry->second.end()) {
	++it;
	continue;
	}
	system_found_count++;
	it = inode_numbers->erase(it);
	FillInodeEntry(AddToCurrentTracePacket(block_device_id), inode_number,
	inode_it->second);
	}
	PERFETTO_DLOG("%" PRIu64 " inodes found in static file map",
	system_found_count);
	}

	void InodeFileDataSource::AddInodesFromLRUCache(
	BlockDeviceID block_device_id,
	std::set<Inode>* inode_numbers) {
	uint64_t cache_found_count = 0;
	for (auto it = inode_numbers->begin(); it != inode_numbers->end();) {
	Inode inode_number = *it;
	auto value = cache_->Get(std::make_pair(block_device_id, inode_number));
	if (value == nullptr) {
	++it;
	continue;
	}
	cache_found_count++;
	it = inode_numbers->erase(it);
	FillInodeEntry(AddToCurrentTracePacket(block_device_id), inode_number,
	*value);
	}
	if (cache_found_count > 0)
	PERFETTO_DLOG("%" PRIu64 " inodes found in cache", cache_found_count);
	}

	void InodeFileDataSource::Flush(FlushRequestID,
	std::function<void()> callback) {
	ResetTracePacket();
	writer_->Flush(callback);
	}

	void InodeFileDataSource::OnInodes(
	const base::FlatSet<InodeBlockPair>& inodes) {
	if (mount_points_.empty()) {
	mount_points_ = ParseMounts();
	}
	// Group inodes from FtraceMetadata by block device
	std::map<BlockDeviceID, std::set<Inode>> inode_file_maps;
	for (const auto& inodes_pair : inodes) {
	Inode inode_number = inodes_pair.first;
	BlockDeviceID block_device_id = inodes_pair.second;
	inode_file_maps[block_device_id].emplace(inode_number);
	}
	if (inode_file_maps.size() > 1)
	PERFETTO_DLOG("Saw %zu block devices.", inode_file_maps.size());

	// Write a TracePacket with an InodeFileMap proto for each block device id
	for (auto& inode_file_map_data : inode_file_maps) {
	BlockDeviceID block_device_id = inode_file_map_data.first;
	std::set<Inode>& inode_numbers = inode_file_map_data.second;
	PERFETTO_DLOG("Saw %zu unique inode numbers.", inode_numbers.size());

	// Add entries to InodeFileMap as inodes are found and resolved to their
	// paths/type
	AddInodesFromStaticMap(block_device_id, &inode_numbers);
	AddInodesFromLRUCache(block_device_id, &inode_numbers);

	if (do_not_scan_)
	inode_numbers.clear();

	// If we defined mount points we want to scan in the config,
	// skip inodes on other mount points.
	if (!scan_mount_points_.empty()) {
	bool process = true;
	auto range = mount_points_.equal_range(block_device_id);
	for (auto it = range.first; it != range.second; ++it) {
	if (scan_mount_points_.count(it->second) == 0) {
	process = false;
	break;
	}
	}
	if (!process)
	continue;
	}

	if (!inode_numbers.empty()) {
	// Try to piggy back the current scan.
	auto it = missing_inodes_.find(block_device_id);
	if (it != missing_inodes_.end()) {
	it->second.insert(inode_numbers.cbegin(), inode_numbers.cend());
	}
	next_missing_inodes_[block_device_id].insert(inode_numbers.cbegin(),
	inode_numbers.cend());
	if (!scan_running_) {
	scan_running_ = true;
	auto weak_this = GetWeakPtr();
	task_runner_->PostDelayedTask(
	[weak_this] {
	if (!weak_this) {
	PERFETTO_DLOG("Giving up filesystem scan.");
	return;
	}
	weak_this->FindMissingInodes();
	},
	scan_delay_ms_);
	}
	}
	}
	}

	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_)
	current_trace_packet_->Finalize();
	current_trace_packet_ = writer_->NewTracePacket();
	current_file_map_ = current_trace_packet_->set_inode_file_map();
	has_current_trace_packet_ = true;

	// Add block device id to InodeFileMap
	current_file_map_->set_block_device_id(
	static_cast<uint64_t>(block_device_id));
	// Add mount points to InodeFileMap
	auto range = mount_points_.equal_range(block_device_id);
	for (std::multimap<BlockDeviceID, std::string>::iterator it = range.first;
	it != range.second; ++it)
	current_file_map_->add_mount_points(it->second.c_str());
	}
	return current_file_map_;
	}

	void InodeFileDataSource::RemoveFromNextMissingInodes(
	BlockDeviceID block_device_id,
	Inode inode_number) {
	auto it = next_missing_inodes_.find(block_device_id);
	if (it == next_missing_inodes_.end())
	return;
	it->second.erase(inode_number);
	}

	bool InodeFileDataSource::OnInodeFound(BlockDeviceID block_device_id,
	Inode inode_number,
	const std::string& path,
	InodeFileMap_Entry_Type inode_type) {
	auto it = missing_inodes_.find(block_device_id);
	if (it == missing_inodes_.end())
	return true;

	size_t n = it->second.erase(inode_number);
	if (n == 0)
	return true;

	if (it->second.empty())
	missing_inodes_.erase(it);

	RemoveFromNextMissingInodes(block_device_id, inode_number);

	std::pair<BlockDeviceID, Inode> key{block_device_id, inode_number};
	auto cur_val = cache_->Get(key);
	if (cur_val) {
	cur_val->AddPath(path);
	FillInodeEntry(AddToCurrentTracePacket(block_device_id), inode_number,
	*cur_val);
	} else {
	InodeMapValue new_val(InodeMapValue(inode_type, {path}));
	cache_->Insert(key, new_val);
	FillInodeEntry(AddToCurrentTracePacket(block_device_id), inode_number,
	new_val);
	}
	PERFETTO_DLOG("Filled %s", path.c_str());
	return !missing_inodes_.empty();
	}

	void InodeFileDataSource::ResetTracePacket() {
	current_block_device_id_ = 0;
	current_file_map_ = nullptr;
	if (has_current_trace_packet_)
	current_trace_packet_->Finalize();
	has_current_trace_packet_ = false;
	}

	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 {
	auto weak_this = GetWeakPtr();
	PERFETTO_DLOG("Starting another filesystem scan.");
	task_runner_->PostDelayedTask(
	[weak_this] {
	if (!weak_this) {
	PERFETTO_DLOG("Giving up filesystem scan.");
	return;
	}
	weak_this->FindMissingInodes();
	},
	scan_delay_ms_);
	}
	}

	void InodeFileDataSource::AddRootsForBlockDevice(
	BlockDeviceID block_device_id,
	std::vector<std::string>* roots) {
	auto range = mount_points_.equal_range(block_device_id);
	for (auto it = range.first; it != range.second; ++it) {
	PERFETTO_DLOG("Trying to replace %s", it->second.c_str());
	auto replace_it = mount_point_mapping_.find(it->second);
	if (replace_it != mount_point_mapping_.end()) {
	roots->insert(roots->end(), replace_it->second.cbegin(),
	replace_it->second.cend());
	return;
	}
	}

	for (auto it = range.first; it != range.second; ++it)
	roots->emplace_back(it->second);
	}

	void InodeFileDataSource::FindMissingInodes() {
	missing_inodes_ = std::move(next_missing_inodes_);
	std::vector<std::string> roots;
	for (auto& p : missing_inodes_)
	AddRootsForBlockDevice(p.first, &roots);

	PERFETTO_DCHECK(file_scanner_.get() == nullptr);
	auto weak_this = GetWeakPtr();
	PERFETTO_DLOG("Starting scan of %s", DbgFmt(roots).c_str());
	file_scanner_ = std::unique_ptr<FileScanner>(new FileScanner(
	std::move(roots), this, scan_interval_ms_, scan_batch_size_));

	file_scanner_->Scan(task_runner_);
	}

	base::WeakPtr<InodeFileDataSource> InodeFileDataSource::GetWeakPtr() const {
	return weak_factory_.GetWeakPtr();
	}

	} // namespace perfetto