Cache result of GetLogicalBufferSize in Linux (#6457)

Summary:
In Linux, when reopening DB with many SST files, profiling shows that 100% system cpu time spent for a couple of seconds for `GetLogicalBufferSize`. This slows down MyRocks' recovery time when site is down.

This PR introduces two new APIs:
1. `Env::RegisterDbPaths` and `Env::UnregisterDbPaths` lets `DB` tell the env when it starts or stops using its database directories . The `PosixFileSystem` takes this opportunity to set up a cache from database directories to the corresponding logical block sizes.
2. `LogicalBlockSizeCache` is defined only for OS_LINUX to cache the logical block sizes.

Other modifications:
1. rename `logical buffer size` to `logical block size` to be consistent with Linux terms.
2. declare `GetLogicalBlockSize` in `PosixHelper` to expose it to `PosixFileSystem`.
3. change the functions `IOError` and `IOStatus` in `env/io_posix.h` to have external linkage since they are used in other translation units too.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6457

Test Plan:
1. A new unit test is added for `LogicalBlockSizeCache` in `env/io_posix_test.cc`.
2. A new integration test is added for `DB` operations related to the cache in `db/db_logical_block_size_cache_test.cc`.

`make check`

Differential Revision: D20131243

Pulled By: cheng-chang

fbshipit-source-id: 3077c50f8065c0bffb544d8f49fb10bba9408d04

CMakeLists.txt

@@ -973,6 +973,7 @@ if(WITH_TESTS)
         db/db_tailing_iter_test.cc
         db/db_test.cc
         db/db_test2.cc
+        db/db_logical_block_size_cache_test.cc
         db/db_universal_compaction_test.cc
         db/db_wal_test.cc
         db/db_write_test.cc
@@ -1009,6 +1010,7 @@ if(WITH_TESTS)
         db/write_controller_test.cc
         env/env_basic_test.cc
         env/env_test.cc
+        env/io_posix_test.cc
         env/mock_env_test.cc
         file/delete_scheduler_test.cc
         logging/auto_roll_logger_test.cc

Makefile

@@ -459,6 +459,7 @@ TESTS = \
 	env_basic_test \
 	env_test \
 	env_logger_test \
+	io_posix_test \
 	hash_test \
 	random_test \
 	thread_local_test \
@@ -468,6 +469,7 @@ TESTS = \
 	db_wal_test \
 	db_block_cache_test \
 	db_test \
+	db_logical_block_size_cache_test \
 	db_blob_index_test \
 	db_iter_test \
 	db_iter_stress_test \
@@ -1313,6 +1315,9 @@ db_test: db/db_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 db_test2: db/db_test2.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)
 
+db_logical_block_size_cache_test: db/db_logical_block_size_cache_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 db_blob_index_test: db/db_blob_index_test.o db/db_test_util.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)
 
@@ -1480,6 +1485,9 @@ env_basic_test: env/env_basic_test.o $(LIBOBJECTS) $(TESTHARNESS)
 env_test: env/env_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)
 
+io_posix_test: env/io_posix_test.o $(LIBOBJECTS) $(TESTHARNESS)
+	$(AM_LINK)
+
 fault_injection_test: db/fault_injection_test.o $(LIBOBJECTS) $(TESTHARNESS)
 	$(AM_LINK)
 

TARGETS

@@ -802,6 +802,13 @@ ROCKS_TESTS = [
         [],
         [],
     ],
+    [
+        "db_logical_block_size_cache_test",
+        "db/db_logical_block_size_cache_test.cc",
+        "serial",
+        [],
+        [],
+    ],
     [
         "db_memtable_test",
         "db/db_memtable_test.cc",
@@ -1096,6 +1103,13 @@ ROCKS_TESTS = [
         [],
         [],
     ],
+    [
+        "io_posix_test",
+        "env/io_posix_test.cc",
+        "serial",
+        [],
+        [],
+    ],
     [
         "iostats_context_test",
         "monitoring/iostats_context_test.cc",

db/column_family.cc

@@ -471,6 +471,17 @@ void SuperVersionUnrefHandle(void* ptr) {
 }
 }  // anonymous namespace
 
+std::vector<std::string> ColumnFamilyData::GetDbPaths() const {
+  std::vector<std::string> paths;
+  paths.reserve(ioptions_.cf_paths.size());
+  for (const DbPath& db_path : ioptions_.cf_paths) {
+    paths.emplace_back(db_path.path);
+  }
+  return paths;
+}
+
+const uint32_t ColumnFamilyData::kDummyColumnFamilyDataId = port::kMaxUint32;
+
 ColumnFamilyData::ColumnFamilyData(
     uint32_t id, const std::string& name, Version* _dummy_versions,
     Cache* _table_cache, WriteBufferManager* write_buffer_manager,
@@ -507,7 +518,23 @@ ColumnFamilyData::ColumnFamilyData(
       queued_for_compaction_(false),
       prev_compaction_needed_bytes_(0),
       allow_2pc_(db_options.allow_2pc),
-      last_memtable_id_(0) {
+      last_memtable_id_(0),
+      db_paths_registered_(false) {
+  if (id_ != kDummyColumnFamilyDataId) {
+    // TODO(cc): RegisterDbPaths can be expensive, considering moving it
+    // outside of this constructor which might be called with db mutex held.
+    // TODO(cc): considering using ioptions_.fs, currently some tests rely on
+    // EnvWrapper, that's the main reason why we use env here.
+    Status s = ioptions_.env->RegisterDbPaths(GetDbPaths());
+    if (s.ok()) {
+      db_paths_registered_ = true;
+    } else {
+      ROCKS_LOG_ERROR(
+          ioptions_.info_log,
+          "Failed to register data paths of column family (id: %d, name: %s)",
+          id_, name_.c_str());
+    }
+  }
   Ref();
 
   // Convert user defined table properties collector factories to internal ones.
@@ -601,6 +628,18 @@ ColumnFamilyData::~ColumnFamilyData() {
   for (MemTable* m : to_delete) {
     delete m;
   }
+
+  if (db_paths_registered_) {
+    // TODO(cc): considering using ioptions_.fs, currently some tests rely on
+    // EnvWrapper, that's the main reason why we use env here.
+    Status s = ioptions_.env->UnregisterDbPaths(GetDbPaths());
+    if (!s.ok()) {
+      ROCKS_LOG_ERROR(
+          ioptions_.info_log,
+          "Failed to unregister data paths of column family (id: %d, name: %s)",
+          id_, name_.c_str());
+    }
+  }
 }
 
 bool ColumnFamilyData::UnrefAndTryDelete() {
@@ -1363,8 +1402,9 @@ ColumnFamilySet::ColumnFamilySet(const std::string& dbname,
                                  BlockCacheTracer* const block_cache_tracer)
     : max_column_family_(0),
       dummy_cfd_(new ColumnFamilyData(
-          0, "", nullptr, nullptr, nullptr, ColumnFamilyOptions(), *db_options,
+          ColumnFamilyData::kDummyColumnFamilyDataId, "", nullptr, nullptr,
-          file_options, nullptr, block_cache_tracer)),
+          nullptr, ColumnFamilyOptions(), *db_options, file_options, nullptr,
+          block_cache_tracer)),
       default_cfd_cache_(nullptr),
       db_name_(dbname),
       db_options_(db_options),

db/column_family.h

@@ -508,6 +508,7 @@ class ColumnFamilyData {
 
  private:
   friend class ColumnFamilySet;
+  static const uint32_t kDummyColumnFamilyDataId;
   ColumnFamilyData(uint32_t id, const std::string& name,
                    Version* dummy_versions, Cache* table_cache,
                    WriteBufferManager* write_buffer_manager,
@@ -517,6 +518,8 @@ class ColumnFamilyData {
                    ColumnFamilySet* column_family_set,
                    BlockCacheTracer* const block_cache_tracer);
 
+  std::vector<std::string> GetDbPaths() const;
+
   uint32_t id_;
   const std::string name_;
   Version* dummy_versions_;  // Head of circular doubly-linked list of versions.
@@ -593,6 +596,8 @@ class ColumnFamilyData {
 
   // Directories corresponding to cf_paths.
   std::vector<std::shared_ptr<FSDirectory>> data_dirs_;
+
+  bool db_paths_registered_;
 };
 
 // ColumnFamilySet has interesting thread-safety requirements

db/db_impl/db_impl.cc

@@ -21,7 +21,6 @@
 #include <stdexcept>
 #include <string>
 #include <unordered_map>
-#include <unordered_set>
 #include <utility>
 #include <vector>
 
@@ -3528,24 +3527,15 @@ Status DestroyDB(const std::string& dbname, const Options& options,
       }
     }
 
-    std::vector<std::string> paths;
+    std::set<std::string> paths;
-
+    for (const DbPath& db_path : options.db_paths) {
-    for (const auto& path : options.db_paths) {
+      paths.insert(db_path.path);
-      paths.emplace_back(path.path);
     }
-    for (const auto& cf : column_families) {
+    for (const ColumnFamilyDescriptor& cf : column_families) {
-      for (const auto& path : cf.options.cf_paths) {
+      for (const DbPath& cf_path : cf.options.cf_paths) {
-        paths.emplace_back(path.path);
+        paths.insert(cf_path.path);
       }
     }
-
-    // Remove duplicate paths.
-    // Note that we compare only the actual paths but not path ids.
-    // This reason is that same path can appear at different path_ids
-    // for different column families.
-    std::sort(paths.begin(), paths.end());
-    paths.erase(std::unique(paths.begin(), paths.end()), paths.end());
-
     for (const auto& path : paths) {
       if (env->GetChildren(path, &filenames).ok()) {
         for (const auto& fname : filenames) {

db/db_impl/db_impl_open.cc

@@ -1401,13 +1401,9 @@ Status DBImpl::Open(const DBOptions& db_options, const std::string& dbname,
       impl->error_handler_.EnableAutoRecovery();
     }
   }
-
+  if (s.ok()) {
-  if (!s.ok()) {
-    delete impl;
-    return s;
-  }
-
     s = impl->CreateArchivalDirectory();
+  }
   if (!s.ok()) {
     delete impl;
     return s;

db/db_logical_block_size_cache_test.cc

@@ -0,0 +1,483 @@
+// Copyright (c) 2020-present, Facebook, Inc.  All rights reserved.
+// This source code is licensed under both the GPLv2 (found in the
+// COPYING file in the root directory) and Apache 2.0 License
+// (found in the LICENSE.Apache file in the root directory).
+
+#include "test_util/testharness.h"
+
+#ifdef OS_LINUX
+#include "env/io_posix.h"
+#include "rocksdb/db.h"
+#include "rocksdb/env.h"
+
+namespace ROCKSDB_NAMESPACE {
+class EnvWithCustomLogicalBlockSizeCache : public EnvWrapper {
+ public:
+  EnvWithCustomLogicalBlockSizeCache(Env* env, LogicalBlockSizeCache* cache)
+      : EnvWrapper(env), cache_(cache) {}
+
+  Status RegisterDbPaths(const std::vector<std::string>& paths) override {
+    return cache_->RefAndCacheLogicalBlockSize(paths);
+  }
+
+  Status UnregisterDbPaths(const std::vector<std::string>& paths) override {
+    cache_->UnrefAndTryRemoveCachedLogicalBlockSize(paths);
+    return Status::OK();
+  }
+
+ private:
+  LogicalBlockSizeCache* cache_;
+};
+
+class DBLogicalBlockSizeCacheTest : public testing::Test {
+ public:
+  DBLogicalBlockSizeCacheTest()
+      : dbname_(test::PerThreadDBPath("logical_block_size_cache_test")),
+        data_path_0_(dbname_ + "/data_path_0"),
+        data_path_1_(dbname_ + "/data_path_1"),
+        cf_path_0_(dbname_ + "/cf_path_0"),
+        cf_path_1_(dbname_ + "/cf_path_1") {
+    auto get_fd_block_size = [&](int fd) {
+      return fd;
+    };
+    auto get_dir_block_size = [&](const std::string& /*dir*/, size_t* size) {
+      *size = 1024;
+      return Status::OK();
+    };
+    cache_.reset(new LogicalBlockSizeCache(
+        get_fd_block_size, get_dir_block_size));
+    env_.reset(new EnvWithCustomLogicalBlockSizeCache(
+        Env::Default(), cache_.get()));
+  }
+
+ protected:
+  std::string dbname_;
+  std::string data_path_0_;
+  std::string data_path_1_;
+  std::string cf_path_0_;
+  std::string cf_path_1_;
+  std::unique_ptr<LogicalBlockSizeCache> cache_;
+  std::unique_ptr<Env> env_;
+};
+
+TEST_F(DBLogicalBlockSizeCacheTest, OpenClose) {
+  // Tests that Open will cache the logical block size for data paths,
+  // and Close will remove the cached sizes.
+  Options options;
+  options.create_if_missing = true;
+  options.env = env_.get();
+  options.db_paths = {{data_path_0_, 2048}, {data_path_1_, 2048}};
+
+  for (int i = 0; i < 2; i++) {
+    DB* db;
+    if (!i) {
+      printf("Open\n");
+      ASSERT_OK(DB::Open(options, dbname_, &db));
+    } else {
+      printf("OpenForReadOnly\n");
+      ASSERT_OK(DB::OpenForReadOnly(options, dbname_, &db));
+    }
+    ASSERT_EQ(2, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(data_path_0_));
+    ASSERT_EQ(1, cache_->GetRefCount(data_path_0_));
+    ASSERT_TRUE(cache_->Contains(data_path_1_));
+    ASSERT_EQ(1, cache_->GetRefCount(data_path_1_));
+    ASSERT_OK(db->Close());
+    ASSERT_EQ(0, cache_->Size());
+    delete db;
+  }
+}
+
+TEST_F(DBLogicalBlockSizeCacheTest, OpenDelete) {
+  // Tests that Open will cache the logical block size for data paths,
+  // and delete the db pointer will remove the cached sizes.
+  Options options;
+  options.create_if_missing = true;
+  options.env = env_.get();
+
+  for (int i = 0; i < 2; i++) {
+    DB* db;
+    if (!i) {
+      printf("Open\n");
+      ASSERT_OK(DB::Open(options, dbname_, &db));
+    } else {
+      printf("OpenForReadOnly\n");
+      ASSERT_OK(DB::OpenForReadOnly(options, dbname_, &db));
+    }
+    ASSERT_EQ(1, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(dbname_));
+    ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+    delete db;
+    ASSERT_EQ(0, cache_->Size());
+  }
+}
+
+TEST_F(DBLogicalBlockSizeCacheTest, CreateColumnFamily) {
+  // Tests that CreateColumnFamily will cache the cf_paths,
+  // drop the column family handle won't drop the cache,
+  // drop and then delete the column family handle will drop the cache.
+  Options options;
+  options.create_if_missing = true;
+  options.env = env_.get();
+  ColumnFamilyOptions cf_options;
+  cf_options.cf_paths = {{cf_path_0_, 1024}, {cf_path_1_, 2048}};
+
+  DB* db;
+  ASSERT_OK(DB::Open(options, dbname_, &db));
+  ASSERT_EQ(1, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+
+  ColumnFamilyHandle* cf = nullptr;
+  ASSERT_OK(db->CreateColumnFamily(cf_options, "cf", &cf));
+  ASSERT_EQ(3, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+  ASSERT_TRUE(cache_->Contains(cf_path_1_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_1_));
+
+  // Drop column family does not drop cache.
+  ASSERT_OK(db->DropColumnFamily(cf));
+  ASSERT_EQ(3, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+  ASSERT_TRUE(cache_->Contains(cf_path_1_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_1_));
+
+  // Delete handle will drop cache.
+  ASSERT_OK(db->DestroyColumnFamilyHandle(cf));
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+
+  delete db;
+  ASSERT_EQ(0, cache_->Size());
+}
+
+TEST_F(DBLogicalBlockSizeCacheTest, CreateColumnFamilies) {
+  // Tests that CreateColumnFamilies will cache the cf_paths,
+  // drop the column family handle won't drop the cache,
+  // drop and then delete the column family handle will drop the cache.
+  Options options;
+  options.create_if_missing = true;
+  options.env = env_.get();
+  ColumnFamilyOptions cf_options;
+  cf_options.cf_paths = {{cf_path_0_, 1024}};
+
+  DB* db;
+  ASSERT_OK(DB::Open(options, dbname_, &db));
+  ASSERT_EQ(1, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+
+  std::vector<ColumnFamilyHandle*> cfs;
+  ASSERT_OK(db->CreateColumnFamilies(cf_options, {"cf1", "cf2"}, &cfs));
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(2, cache_->GetRefCount(cf_path_0_));
+
+  // Drop column family does not drop cache.
+  for (ColumnFamilyHandle* cf : cfs) {
+    ASSERT_OK(db->DropColumnFamily(cf));
+    ASSERT_EQ(2, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(dbname_));
+    ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+    ASSERT_TRUE(cache_->Contains(cf_path_0_));
+    ASSERT_EQ(2, cache_->GetRefCount(cf_path_0_));
+  }
+
+  // Delete one handle will not drop cache because another handle is still
+  // referencing cf_path_0_.
+  ASSERT_OK(db->DestroyColumnFamilyHandle(cfs[0]));
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+  // Delete the last handle will drop cache.
+  ASSERT_OK(db->DestroyColumnFamilyHandle(cfs[1]));
+  ASSERT_EQ(1, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+
+  delete db;
+  ASSERT_EQ(0, cache_->Size());
+}
+
+TEST_F(DBLogicalBlockSizeCacheTest, OpenWithColumnFamilies) {
+  // Tests that Open two column families with the same cf_path will cache the
+  // cf_path and have 2 references to the cached size,
+  // drop the column family handle won't drop the cache,
+  // drop and then delete the column family handle will drop the cache.
+  Options options;
+  options.create_if_missing = true;
+  options.env = env_.get();
+
+  ColumnFamilyOptions cf_options;
+  cf_options.cf_paths = {{cf_path_0_, 1024}};
+
+  for (int i = 0; i < 2; i++) {
+    DB* db;
+    ColumnFamilyHandle* cf1 = nullptr;
+    ColumnFamilyHandle* cf2 = nullptr;
+    ASSERT_OK(DB::Open(options, dbname_, &db));
+    ASSERT_OK(db->CreateColumnFamily(cf_options, "cf1", &cf1));
+    ASSERT_OK(db->CreateColumnFamily(cf_options, "cf2", &cf2));
+    ASSERT_OK(db->DestroyColumnFamilyHandle(cf1));
+    ASSERT_OK(db->DestroyColumnFamilyHandle(cf2));
+    delete db;
+    ASSERT_EQ(0, cache_->Size());
+
+    std::vector<ColumnFamilyHandle*> cfs;
+    if (!i) {
+      printf("Open\n");
+      ASSERT_OK(DB::Open(options, dbname_,
+                         {{"cf1", cf_options},
+                          {"cf2", cf_options},
+                          {"default", ColumnFamilyOptions()}},
+                         &cfs, &db));
+    } else {
+      printf("OpenForReadOnly\n");
+      ASSERT_OK(DB::OpenForReadOnly(options, dbname_,
+                                    {{"cf1", cf_options},
+                                     {"cf2", cf_options},
+                                     {"default", ColumnFamilyOptions()}},
+                                    &cfs, &db));
+    }
+
+    // Logical block sizes of dbname_ and cf_path_0_ are cached during Open.
+    ASSERT_EQ(2, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(dbname_));
+    ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+    ASSERT_TRUE(cache_->Contains(cf_path_0_));
+    ASSERT_EQ(2, cache_->GetRefCount(cf_path_0_));
+
+    // Drop handles won't drop the cache.
+    ASSERT_OK(db->DropColumnFamily(cfs[0]));
+    ASSERT_OK(db->DropColumnFamily(cfs[1]));
+    ASSERT_EQ(2, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(dbname_));
+    ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+    ASSERT_TRUE(cache_->Contains(cf_path_0_));
+    ASSERT_EQ(2, cache_->GetRefCount(cf_path_0_));
+
+    // Delete 1st handle won't drop the cache for cf_path_0_.
+    ASSERT_OK(db->DestroyColumnFamilyHandle(cfs[0]));
+    ASSERT_EQ(2, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(dbname_));
+    ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+    ASSERT_TRUE(cache_->Contains(cf_path_0_));
+    ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+    // Delete 2nd handle will drop the cache for cf_path_0_.
+    ASSERT_OK(db->DestroyColumnFamilyHandle(cfs[1]));
+    ASSERT_EQ(1, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(dbname_));
+    ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+
+    // Delete the default handle won't affect the cache because db still refers
+    // to the default CF.
+    ASSERT_OK(db->DestroyColumnFamilyHandle(cfs[2]));
+    ASSERT_EQ(1, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(dbname_));
+    ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+
+    delete db;
+    ASSERT_EQ(0, cache_->Size());
+  }
+}
+
+TEST_F(DBLogicalBlockSizeCacheTest, DestroyColumnFamilyHandle) {
+  // Tests that destroy column family without dropping won't drop the cache,
+  // because compaction and flush might still need to get logical block size
+  // when opening new files.
+  Options options;
+  options.create_if_missing = true;
+  options.env = env_.get();
+  ColumnFamilyOptions cf_options;
+  cf_options.cf_paths = {{cf_path_0_, 1024}};
+
+  DB* db;
+  ASSERT_OK(DB::Open(options, dbname_, &db));
+  ASSERT_EQ(1, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+  ColumnFamilyHandle* cf = nullptr;
+  ASSERT_OK(db->CreateColumnFamily(cf_options, "cf", &cf));
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+  // Delete handle won't drop cache.
+  ASSERT_OK(db->DestroyColumnFamilyHandle(cf));
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(dbname_));
+  ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+  delete db;
+  ASSERT_EQ(0, cache_->Size());
+
+  // Open with column families.
+  std::vector<ColumnFamilyHandle*> cfs;
+  for (int i = 0; i < 2; i++) {
+    if (!i) {
+      printf("Open\n");
+      ASSERT_OK(DB::Open(
+          options, dbname_,
+          {{"cf", cf_options}, {"default", ColumnFamilyOptions()}}, &cfs, &db));
+    } else {
+      printf("OpenForReadOnly\n");
+      ASSERT_OK(DB::OpenForReadOnly(
+          options, dbname_,
+          {{"cf", cf_options}, {"default", ColumnFamilyOptions()}}, &cfs, &db));
+    }
+    // cf_path_0_ and dbname_ are cached.
+    ASSERT_EQ(2, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(dbname_));
+    ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+    ASSERT_TRUE(cache_->Contains(cf_path_0_));
+    ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+    // Deleting handle won't drop cache.
+    ASSERT_OK(db->DestroyColumnFamilyHandle(cfs[0]));
+    ASSERT_OK(db->DestroyColumnFamilyHandle(cfs[1]));
+    ASSERT_EQ(2, cache_->Size());
+    ASSERT_TRUE(cache_->Contains(dbname_));
+    ASSERT_EQ(1, cache_->GetRefCount(dbname_));
+    ASSERT_TRUE(cache_->Contains(cf_path_0_));
+    ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+    delete db;
+    ASSERT_EQ(0, cache_->Size());
+  }
+}
+
+TEST_F(DBLogicalBlockSizeCacheTest, MultiDBWithDifferentPaths) {
+  // Tests the cache behavior when there are multiple DBs sharing the same env
+  // with different db_paths and cf_paths.
+  Options options;
+  options.create_if_missing = true;
+  options.env = env_.get();
+
+  DB* db0;
+  ASSERT_OK(DB::Open(options, data_path_0_, &db0));
+  ASSERT_EQ(1, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_0_));
+
+  ColumnFamilyOptions cf_options0;
+  cf_options0.cf_paths = {{cf_path_0_, 1024}};
+  ColumnFamilyHandle* cf0;
+  db0->CreateColumnFamily(cf_options0, "cf", &cf0);
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(data_path_0_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+  DB* db1;
+  ASSERT_OK(DB::Open(options, data_path_1_, &db1));
+  ASSERT_EQ(3, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(data_path_0_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+  ASSERT_TRUE(cache_->Contains(data_path_1_));
+  ASSERT_EQ(1, cache_->GetRefCount(data_path_1_));
+
+  ColumnFamilyOptions cf_options1;
+  cf_options1.cf_paths = {{cf_path_1_, 1024}};
+  ColumnFamilyHandle* cf1;
+  db1->CreateColumnFamily(cf_options1, "cf", &cf1);
+  ASSERT_EQ(4, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(data_path_0_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+  ASSERT_TRUE(cache_->Contains(data_path_1_));
+  ASSERT_EQ(1, cache_->GetRefCount(data_path_1_));
+  ASSERT_TRUE(cache_->Contains(cf_path_1_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_1_));
+
+  db0->DestroyColumnFamilyHandle(cf0);
+  delete db0;
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_1_));
+  ASSERT_EQ(1, cache_->GetRefCount(data_path_1_));
+  ASSERT_TRUE(cache_->Contains(cf_path_1_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_1_));
+
+  db1->DestroyColumnFamilyHandle(cf1);
+  delete db1;
+  ASSERT_EQ(0, cache_->Size());
+}
+
+TEST_F(DBLogicalBlockSizeCacheTest, MultiDBWithSamePaths) {
+  // Tests the cache behavior when there are multiple DBs sharing the same env
+  // with the same db_paths and cf_paths.
+  Options options;
+  options.create_if_missing = true;
+  options.env = env_.get();
+  options.db_paths = {{data_path_0_, 1024}};
+  ColumnFamilyOptions cf_options;
+  cf_options.cf_paths = {{cf_path_0_, 1024}};
+
+  DB* db0;
+  ASSERT_OK(DB::Open(options, dbname_ + "/db0", &db0));
+  ASSERT_EQ(1, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(data_path_0_));
+
+  ColumnFamilyHandle* cf0;
+  db0->CreateColumnFamily(cf_options, "cf", &cf0);
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(data_path_0_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+  DB* db1;
+  ASSERT_OK(DB::Open(options, dbname_ + "/db1", &db1));
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_0_));
+  ASSERT_EQ(2, cache_->GetRefCount(data_path_0_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+  ColumnFamilyHandle* cf1;
+  db1->CreateColumnFamily(cf_options, "cf", &cf1);
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_0_));
+  ASSERT_EQ(2, cache_->GetRefCount(data_path_0_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(2, cache_->GetRefCount(cf_path_0_));
+
+  db0->DestroyColumnFamilyHandle(cf0);
+  delete db0;
+  ASSERT_EQ(2, cache_->Size());
+  ASSERT_TRUE(cache_->Contains(data_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(data_path_0_));
+  ASSERT_TRUE(cache_->Contains(cf_path_0_));
+  ASSERT_EQ(1, cache_->GetRefCount(cf_path_0_));
+
+  db1->DestroyColumnFamilyHandle(cf1);
+  delete db1;
+  ASSERT_EQ(0, cache_->Size());
+}
+
+}  // namespace ROCKSDB_NAMESPACE
+#endif // OS_LINUX
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}

db/version_builder.cc

@@ -405,7 +405,7 @@ class VersionBuilder::Rep {
     size_t max_load = port::kMaxSizet;
 
     if (!always_load) {
-      // If it is initial loading and not set to always laoding all the
+      // If it is initial loading and not set to always loading all the
       // files, we only load up to kInitialLoadLimit files, to limit the
       // time reopening the DB.
       const size_t kInitialLoadLimit = 16;

env/composite_env_wrapper.h

@@ -300,6 +300,13 @@ class CompositeEnvWrapper : public Env {
 
   FileSystem* fs_env_target() const { return fs_env_target_; }
 
+  Status RegisterDbPaths(const std::vector<std::string>& paths) override {
+    return fs_env_target_->RegisterDbPaths(paths);
+  }
+  Status UnregisterDbPaths(const std::vector<std::string>& paths) override {
+    return fs_env_target_->UnregisterDbPaths(paths);
+  }
+
   // The following text is boilerplate that forwards all methods to target()
   Status NewSequentialFile(const std::string& f,
                            std::unique_ptr<SequentialFile>* r,

env/env_chroot.cc

@@ -38,6 +38,32 @@ class ChrootEnv : public EnvWrapper {
 #endif
   }
 
+  Status RegisterDbPaths(const std::vector<std::string>& paths) override {
+    std::vector<std::string> encoded_paths;
+    encoded_paths.reserve(paths.size());
+    for (auto& path : paths) {
+      auto status_and_enc_path = EncodePathWithNewBasename(path);
+      if (!status_and_enc_path.first.ok()) {
+        return status_and_enc_path.first;
+      }
+      encoded_paths.emplace_back(status_and_enc_path.second);
+    }
+    return EnvWrapper::Env::RegisterDbPaths(encoded_paths);
+  }
+
+  Status UnregisterDbPaths(const std::vector<std::string>& paths) override {
+    std::vector<std::string> encoded_paths;
+    encoded_paths.reserve(paths.size());
+    for (auto& path : paths) {
+      auto status_and_enc_path = EncodePathWithNewBasename(path);
+      if (!status_and_enc_path.first.ok()) {
+        return status_and_enc_path.first;
+      }
+      encoded_paths.emplace_back(status_and_enc_path.second);
+    }
+    return EnvWrapper::Env::UnregisterDbPaths(encoded_paths);
+  }
+
   Status NewSequentialFile(const std::string& fname,
                            std::unique_ptr<SequentialFile>* result,
                            const EnvOptions& options) override {

env/fs_posix.cc

@@ -183,7 +183,8 @@ class PosixFileSystem : public FileSystem {
                        errno);
       }
     }
-    result->reset(new PosixSequentialFile(fname, file, fd, options));
+    result->reset(new PosixSequentialFile(
+        fname, file, fd, GetLogicalBlockSize(fname, fd), options));
     return IOStatus::OK();
   }
 
@@ -242,7 +243,8 @@ class PosixFileSystem : public FileSystem {
         }
 #endif
       }
-      result->reset(new PosixRandomAccessFile(fname, fd, options
+      result->reset(new PosixRandomAccessFile(
+          fname, fd, GetLogicalBlockSize(fname, fd), options
 #if defined(ROCKSDB_IOURING_PRESENT)
           ,
           thread_local_io_urings_.get()
@@ -328,12 +330,14 @@ class PosixFileSystem : public FileSystem {
         }
       }
 #endif
-      result->reset(new PosixWritableFile(fname, fd, options));
+      result->reset(new PosixWritableFile(
+          fname, fd, GetLogicalBlockSize(fname, fd), options));
     } else {
       // disable mmap writes
       EnvOptions no_mmap_writes_options = options;
       no_mmap_writes_options.use_mmap_writes = false;
-      result->reset(new PosixWritableFile(fname, fd, no_mmap_writes_options));
+      result->reset(new PosixWritableFile(
+          fname, fd, GetLogicalBlockSize(fname, fd), no_mmap_writes_options));
     }
     return s;
   }
@@ -428,12 +432,14 @@ class PosixFileSystem : public FileSystem {
         }
       }
 #endif
-      result->reset(new PosixWritableFile(fname, fd, options));
+      result->reset(new PosixWritableFile(
+          fname, fd, GetLogicalBlockSize(fname, fd), options));
     } else {
       // disable mmap writes
       FileOptions no_mmap_writes_options = options;
       no_mmap_writes_options.use_mmap_writes = false;
-      result->reset(new PosixWritableFile(fname, fd, no_mmap_writes_options));
+      result->reset(new PosixWritableFile(
+          fname, fd, GetLogicalBlockSize(fname, fd), no_mmap_writes_options));
     }
     return s;
   }
@@ -853,7 +859,15 @@ class PosixFileSystem : public FileSystem {
     optimized.fallocate_with_keep_size = true;
     return optimized;
   }
-
+#ifdef OS_LINUX
+  Status RegisterDbPaths(const std::vector<std::string>& paths) override {
+    return logical_block_size_cache_.RefAndCacheLogicalBlockSize(paths);
+  }
+  Status UnregisterDbPaths(const std::vector<std::string>& paths) override {
+    logical_block_size_cache_.UnrefAndTryRemoveCachedLogicalBlockSize(paths);
+    return Status::OK();
+  }
+#endif
  private:
   bool checkedDiskForMmap_;
   bool forceMmapOff_;  // do we override Env options?
@@ -899,8 +913,26 @@ class PosixFileSystem : public FileSystem {
   // If true, allow non owner read access for db files. Otherwise, non-owner
   //  has no access to db files.
   bool allow_non_owner_access_;
+
+#ifdef OS_LINUX
+  static LogicalBlockSizeCache logical_block_size_cache_;
+#endif
+  static size_t GetLogicalBlockSize(const std::string& fname, int fd);
 };
 
+#ifdef OS_LINUX
+LogicalBlockSizeCache PosixFileSystem::logical_block_size_cache_;
+#endif
+
+size_t PosixFileSystem::GetLogicalBlockSize(const std::string& fname, int fd) {
+#ifdef OS_LINUX
+  return logical_block_size_cache_.GetLogicalBlockSize(fname, fd);
+#else
+  (void) fname;
+  return PosixHelper::GetLogicalBlockSizeOfFd(fd);
+#endif
+}
+
 PosixFileSystem::PosixFileSystem()
     : checkedDiskForMmap_(false),
       forceMmapOff_(false),

env/io_posix.cc

@@ -45,6 +45,35 @@
 
 namespace ROCKSDB_NAMESPACE {
 
+std::string IOErrorMsg(const std::string& context,
+                       const std::string& file_name) {
+  if (file_name.empty()) {
+    return context;
+  }
+  return context + ": " + file_name;
+}
+
+// file_name can be left empty if it is not unkown.
+IOStatus IOError(const std::string& context, const std::string& file_name,
+                 int err_number) {
+  switch (err_number) {
+    case ENOSPC: {
+      IOStatus s = IOStatus::NoSpace(IOErrorMsg(context, file_name),
+                                     strerror(err_number));
+      s.SetRetryable(true);
+      return s;
+    }
+    case ESTALE:
+      return IOStatus::IOError(IOStatus::kStaleFile);
+    case ENOENT:
+      return IOStatus::PathNotFound(IOErrorMsg(context, file_name),
+                                    strerror(err_number));
+    default:
+      return IOStatus::IOError(IOErrorMsg(context, file_name),
+                               strerror(err_number));
+  }
+}
+
 // A wrapper for fadvise, if the platform doesn't support fadvise,
 // it will simply return 0.
 int Fadvise(int fd, off_t offset, size_t len, int advice) {
@@ -112,75 +141,6 @@ bool PosixPositionedWrite(int fd, const char* buf, size_t nbyte, off_t offset) {
   return true;
 }
 
-size_t GetLogicalBufferSize(int __attribute__((__unused__)) fd) {
-#ifdef OS_LINUX
-  struct stat buf;
-  int result = fstat(fd, &buf);
-  if (result == -1) {
-    return kDefaultPageSize;
-  }
-  if (major(buf.st_dev) == 0) {
-    // Unnamed devices (e.g. non-device mounts), reserved as null device number.
-    // These don't have an entry in /sys/dev/block/. Return a sensible default.
-    return kDefaultPageSize;
-  }
-
-  // Reading queue/logical_block_size does not require special permissions.
-  const int kBufferSize = 100;
-  char path[kBufferSize];
-  char real_path[PATH_MAX + 1];
-  snprintf(path, kBufferSize, "/sys/dev/block/%u:%u", major(buf.st_dev),
-           minor(buf.st_dev));
-  if (realpath(path, real_path) == nullptr) {
-    return kDefaultPageSize;
-  }
-  std::string device_dir(real_path);
-  if (!device_dir.empty() && device_dir.back() == '/') {
-    device_dir.pop_back();
-  }
-  // NOTE: sda3 and nvme0n1p1 do not have a `queue/` subdir, only the parent sda
-  // and nvme0n1 have it.
-  // $ ls -al '/sys/dev/block/8:3'
-  // lrwxrwxrwx. 1 root root 0 Jun 26 01:38 /sys/dev/block/8:3 ->
-  // ../../block/sda/sda3
-  // $ ls -al '/sys/dev/block/259:4'
-  // lrwxrwxrwx 1 root root 0 Jan 31 16:04 /sys/dev/block/259:4 ->
-  // ../../devices/pci0000:17/0000:17:00.0/0000:18:00.0/nvme/nvme0/nvme0n1/nvme0n1p1
-  size_t parent_end = device_dir.rfind('/', device_dir.length() - 1);
-  if (parent_end == std::string::npos) {
-    return kDefaultPageSize;
-  }
-  size_t parent_begin = device_dir.rfind('/', parent_end - 1);
-  if (parent_begin == std::string::npos) {
-    return kDefaultPageSize;
-  }
-  std::string parent =
-      device_dir.substr(parent_begin + 1, parent_end - parent_begin - 1);
-  std::string child = device_dir.substr(parent_end + 1, std::string::npos);
-  if (parent != "block" &&
-      (child.compare(0, 4, "nvme") || child.find('p') != std::string::npos)) {
-    device_dir = device_dir.substr(0, parent_end);
-  }
-  std::string fname = device_dir + "/queue/logical_block_size";
-  FILE* fp;
-  size_t size = 0;
-  fp = fopen(fname.c_str(), "r");
-  if (fp != nullptr) {
-    char* line = nullptr;
-    size_t len = 0;
-    if (getline(&line, &len, fp) != -1) {
-      sscanf(line, "%zu", &size);
-    }
-    free(line);
-    fclose(fp);
-  }
-  if (size != 0 && (size & (size - 1)) == 0) {
-    return size;
-  }
-#endif
-  return kDefaultPageSize;
-}
-
 #ifdef ROCKSDB_RANGESYNC_PRESENT
 
 #if !defined(ZFS_SUPER_MAGIC)
@@ -247,12 +207,13 @@ bool IsSectorAligned(const void* ptr, size_t sector_size) {
  * PosixSequentialFile
  */
 PosixSequentialFile::PosixSequentialFile(const std::string& fname, FILE* file,
-                                         int fd, const EnvOptions& options)
+                                         int fd, size_t logical_block_size,
+                                         const EnvOptions& options)
     : filename_(fname),
       file_(file),
       fd_(fd),
       use_direct_io_(options.use_direct_reads),
-      logical_sector_size_(GetLogicalBufferSize(fd_)) {
+      logical_sector_size_(logical_block_size) {
   assert(!options.use_direct_reads || !options.use_mmap_reads);
 }
 
@@ -409,13 +370,178 @@ size_t PosixHelper::GetUniqueIdFromFile(int fd, char* id, size_t max_size) {
   return static_cast<size_t>(rid - id);
 }
 #endif
+
+#ifdef OS_LINUX
+std::string RemoveTrailingSlash(const std::string& path) {
+  std::string p = path;
+  if (p.size() > 1 && p.back() == '/') {
+    p.pop_back();
+  }
+  return p;
+}
+
+Status LogicalBlockSizeCache::RefAndCacheLogicalBlockSize(
+    const std::vector<std::string>& directories) {
+  std::vector<std::string> dirs;
+  dirs.reserve(directories.size());
+  for (auto& d : directories) {
+    dirs.emplace_back(RemoveTrailingSlash(d));
+  }
+
+  std::map<std::string, size_t> dir_sizes;
+  {
+    ReadLock lock(&cache_mutex_);
+    for (const auto& dir : dirs) {
+      if (cache_.find(dir) == cache_.end()) {
+        dir_sizes.emplace(dir, 0);
+      }
+    }
+  }
+
+  Status s;
+  for (auto& dir_size : dir_sizes) {
+    s = get_logical_block_size_of_directory_(dir_size.first, &dir_size.second);
+    if (!s.ok()) {
+      return s;
+    }
+  }
+
+  WriteLock lock(&cache_mutex_);
+  for (const auto& dir : dirs) {
+    auto& v = cache_[dir];
+    v.ref++;
+    auto dir_size = dir_sizes.find(dir);
+    if (dir_size != dir_sizes.end()) {
+      v.size = dir_size->second;
+    }
+  }
+  return Status::OK();
+}
+
+void LogicalBlockSizeCache::UnrefAndTryRemoveCachedLogicalBlockSize(
+    const std::vector<std::string>& directories) {
+  std::vector<std::string> dirs;
+  dirs.reserve(directories.size());
+  for (auto& dir : directories) {
+    dirs.emplace_back(RemoveTrailingSlash(dir));
+  }
+
+  WriteLock lock(&cache_mutex_);
+  for (const auto& dir : dirs) {
+    auto it = cache_.find(dir);
+    if (it != cache_.end() && !(--(it->second.ref))) {
+      cache_.erase(it);
+    }
+  }
+}
+
+size_t LogicalBlockSizeCache::GetLogicalBlockSize(const std::string& fname,
+                                                  int fd) {
+  std::string dir = fname.substr(0, fname.find_last_of("/"));
+  if (dir.empty()) {
+    dir = "/";
+  }
+  {
+    ReadLock lock(&cache_mutex_);
+    auto it = cache_.find(dir);
+    if (it != cache_.end()) {
+      return it->second.size;
+    }
+  }
+  return get_logical_block_size_of_fd_(fd);
+}
+#endif
+
+Status PosixHelper::GetLogicalBlockSizeOfDirectory(const std::string& directory,
+                                                   size_t* size) {
+  int fd = open(directory.c_str(), O_DIRECTORY | O_RDONLY);
+  if (fd == -1) {
+    close(fd);
+    return Status::IOError("Cannot open directory " + directory);
+  }
+  *size = PosixHelper::GetLogicalBlockSizeOfFd(fd);
+  close(fd);
+  return Status::OK();
+}
+
+size_t PosixHelper::GetLogicalBlockSizeOfFd(int fd) {
+#ifdef OS_LINUX
+  struct stat buf;
+  int result = fstat(fd, &buf);
+  if (result == -1) {
+    return kDefaultPageSize;
+  }
+  if (major(buf.st_dev) == 0) {
+    // Unnamed devices (e.g. non-device mounts), reserved as null device number.
+    // These don't have an entry in /sys/dev/block/. Return a sensible default.
+    return kDefaultPageSize;
+  }
+
+  // Reading queue/logical_block_size does not require special permissions.
+  const int kBufferSize = 100;
+  char path[kBufferSize];
+  char real_path[PATH_MAX + 1];
+  snprintf(path, kBufferSize, "/sys/dev/block/%u:%u", major(buf.st_dev),
+           minor(buf.st_dev));
+  if (realpath(path, real_path) == nullptr) {
+    return kDefaultPageSize;
+  }
+  std::string device_dir(real_path);
+  if (!device_dir.empty() && device_dir.back() == '/') {
+    device_dir.pop_back();
+  }
+  // NOTE: sda3 and nvme0n1p1 do not have a `queue/` subdir, only the parent sda
+  // and nvme0n1 have it.
+  // $ ls -al '/sys/dev/block/8:3'
+  // lrwxrwxrwx. 1 root root 0 Jun 26 01:38 /sys/dev/block/8:3 ->
+  // ../../block/sda/sda3
+  // $ ls -al '/sys/dev/block/259:4'
+  // lrwxrwxrwx 1 root root 0 Jan 31 16:04 /sys/dev/block/259:4 ->
+  // ../../devices/pci0000:17/0000:17:00.0/0000:18:00.0/nvme/nvme0/nvme0n1/nvme0n1p1
+  size_t parent_end = device_dir.rfind('/', device_dir.length() - 1);
+  if (parent_end == std::string::npos) {
+    return kDefaultPageSize;
+  }
+  size_t parent_begin = device_dir.rfind('/', parent_end - 1);
+  if (parent_begin == std::string::npos) {
+    return kDefaultPageSize;
+  }
+  std::string parent =
+      device_dir.substr(parent_begin + 1, parent_end - parent_begin - 1);
+  std::string child = device_dir.substr(parent_end + 1, std::string::npos);
+  if (parent != "block" &&
+      (child.compare(0, 4, "nvme") || child.find('p') != std::string::npos)) {
+    device_dir = device_dir.substr(0, parent_end);
+  }
+  std::string fname = device_dir + "/queue/logical_block_size";
+  FILE* fp;
+  size_t size = 0;
+  fp = fopen(fname.c_str(), "r");
+  if (fp != nullptr) {
+    char* line = nullptr;
+    size_t len = 0;
+    if (getline(&line, &len, fp) != -1) {
+      sscanf(line, "%zu", &size);
+    }
+    free(line);
+    fclose(fp);
+  }
+  if (size != 0 && (size & (size - 1)) == 0) {
+    return size;
+  }
+#endif
+  (void)fd;
+  return kDefaultPageSize;
+}
+
 /*
  * PosixRandomAccessFile
  *
  * pread() based random-access
  */
 PosixRandomAccessFile::PosixRandomAccessFile(
-    const std::string& fname, int fd, const EnvOptions& options
+    const std::string& fname, int fd, size_t logical_block_size,
+    const EnvOptions& options
 #if defined(ROCKSDB_IOURING_PRESENT)
     ,
     ThreadLocalPtr* thread_local_io_urings
@@ -424,7 +550,7 @@ PosixRandomAccessFile::PosixRandomAccessFile(
     : filename_(fname),
       fd_(fd),
       use_direct_io_(options.use_direct_reads),
-      logical_sector_size_(GetLogicalBufferSize(fd_))
+      logical_sector_size_(logical_block_size)
 #if defined(ROCKSDB_IOURING_PRESENT)
       ,
       thread_local_io_urings_(thread_local_io_urings)
@@ -988,13 +1114,14 @@ IOStatus PosixMmapFile::Allocate(uint64_t offset, uint64_t len,
  * Use posix write to write data to a file.
  */
 PosixWritableFile::PosixWritableFile(const std::string& fname, int fd,
+                                     size_t logical_block_size,
                                      const EnvOptions& options)
     : FSWritableFile(options),
       filename_(fname),
       use_direct_io_(options.use_direct_writes),
       fd_(fd),
       filesize_(0),
-      logical_sector_size_(GetLogicalBufferSize(fd_)) {
+      logical_sector_size_(logical_block_size) {
 #ifdef ROCKSDB_FALLOCATE_PRESENT
   allow_fallocate_ = options.allow_fallocate;
   fallocate_with_keep_size_ = options.fallocate_with_keep_size;

env/io_posix.h

@@ -14,11 +14,15 @@
 #endif
 #include <unistd.h>
 #include <atomic>
+#include <functional>
+#include <map>
 #include <string>
+#include "port/port.h"
 #include "rocksdb/env.h"
-#include "util/thread_local.h"
 #include "rocksdb/file_system.h"
 #include "rocksdb/io_status.h"
+#include "util/mutexlock.h"
+#include "util/thread_local.h"
 
 // For non linux platform, the following macros are used only as place
 // holder.
@@ -31,39 +35,92 @@
 #endif
 
 namespace ROCKSDB_NAMESPACE {
-static std::string IOErrorMsg(const std::string& context,
+std::string IOErrorMsg(const std::string& context,
-                              const std::string& file_name) {
+                       const std::string& file_name);
-  if (file_name.empty()) {
-    return context;
-  }
-  return context + ": " + file_name;
-}
-
 // file_name can be left empty if it is not unkown.
-static IOStatus IOError(const std::string& context,
+IOStatus IOError(const std::string& context, const std::string& file_name,
-                        const std::string& file_name, int err_number) {
+                 int err_number);
-  switch (err_number) {
-    case ENOSPC: {
-      IOStatus s = IOStatus::NoSpace(IOErrorMsg(context, file_name),
-                                     strerror(err_number));
-      s.SetRetryable(true);
-      return s;
-    }
-  case ESTALE:
-    return IOStatus::IOError(IOStatus::kStaleFile);
-  case ENOENT:
-    return IOStatus::PathNotFound(IOErrorMsg(context, file_name),
-                                  strerror(err_number));
-  default:
-    return IOStatus::IOError(IOErrorMsg(context, file_name),
-                             strerror(err_number));
-  }
-}
 
 class PosixHelper {
  public:
   static size_t GetUniqueIdFromFile(int fd, char* id, size_t max_size);
+  static size_t GetLogicalBlockSizeOfFd(int fd);
+  static Status GetLogicalBlockSizeOfDirectory(const std::string& directory,
+                                               size_t* size);
+};
+
+#ifdef OS_LINUX
+// Files under a specific directory have the same logical block size.
+// This class caches the logical block size for the specified directories to
+// save the CPU cost of computing the size.
+// Safe for concurrent access from multiple threads without any external
+// synchronization.
+class LogicalBlockSizeCache {
+ public:
+  LogicalBlockSizeCache(
+      std::function<size_t(int)> get_logical_block_size_of_fd =
+          PosixHelper::GetLogicalBlockSizeOfFd,
+      std::function<Status(const std::string&, size_t*)>
+          get_logical_block_size_of_directory =
+              PosixHelper::GetLogicalBlockSizeOfDirectory)
+      : get_logical_block_size_of_fd_(get_logical_block_size_of_fd),
+        get_logical_block_size_of_directory_(
+            get_logical_block_size_of_directory) {}
+
+  // Takes the following actions:
+  // 1. Increases reference count of the directories;
+  // 2. If the directory's logical block size is not cached,
+  //    compute the buffer size and cache the result.
+  Status RefAndCacheLogicalBlockSize(
+      const std::vector<std::string>& directories);
+
+  // Takes the following actions:
+  // 1. Decreases reference count of the directories;
+  // 2. If the reference count of a directory reaches 0, remove the directory
+  //    from the cache.
+  void UnrefAndTryRemoveCachedLogicalBlockSize(
+      const std::vector<std::string>& directories);
+
+  // Returns the logical block size for the file.
+  //
+  // If the file is under a cached directory, return the cached size.
+  // Otherwise, the size is computed.
+  size_t GetLogicalBlockSize(const std::string& fname, int fd);
+
+  int GetRefCount(const std::string& dir) {
+    ReadLock lock(&cache_mutex_);
+    auto it = cache_.find(dir);
+    if (it == cache_.end()) {
+      return 0;
+    }
+    return it->second.ref;
+  }
+
+  size_t Size() const { return cache_.size(); }
+
+  bool Contains(const std::string& dir) {
+    ReadLock lock(&cache_mutex_);
+    return cache_.find(dir) != cache_.end();
+  }
+
+ private:
+  struct CacheValue {
+    CacheValue() : size(0), ref(0) {}
+
+    // Logical block size of the directory.
+    size_t size;
+    // Reference count of the directory.
+    int ref;
+  };
+
+  std::function<size_t(int)> get_logical_block_size_of_fd_;
+  std::function<Status(const std::string&, size_t*)>
+      get_logical_block_size_of_directory_;
+
+  std::map<std::string, CacheValue> cache_;
+  port::RWMutex cache_mutex_;
 };
+#endif
 
 class PosixSequentialFile : public FSSequentialFile {
  private:
@@ -75,6 +132,7 @@ class PosixSequentialFile : public FSSequentialFile {
 
  public:
   PosixSequentialFile(const std::string& fname, FILE* file, int fd,
+                      size_t logical_block_size,
                       const EnvOptions& options);
   virtual ~PosixSequentialFile();
 
@@ -123,6 +181,7 @@ class PosixRandomAccessFile : public FSRandomAccessFile {
 
  public:
   PosixRandomAccessFile(const std::string& fname, int fd,
+                        size_t logical_block_size,
                         const EnvOptions& options
 #if defined(ROCKSDB_IOURING_PRESENT)
                         ,
@@ -172,6 +231,7 @@ class PosixWritableFile : public FSWritableFile {
 
  public:
   explicit PosixWritableFile(const std::string& fname, int fd,
+                             size_t logical_block_size,
                              const EnvOptions& options);
   virtual ~PosixWritableFile();
 

env/io_posix_test.cc

@@ -0,0 +1,140 @@
+// Copyright (c) 2020-present, Facebook, Inc.  All rights reserved.
+// This source code is licensed under both the GPLv2 (found in the
+// COPYING file in the root directory) and Apache 2.0 License
+// (found in the LICENSE.Apache file in the root directory).
+
+#include "test_util/testharness.h"
+
+#ifdef ROCKSDB_LIB_IO_POSIX
+#include "env/io_posix.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+#ifdef OS_LINUX
+class LogicalBlockSizeCacheTest : public testing::Test {};
+
+// Tests the caching behavior.
+TEST_F(LogicalBlockSizeCacheTest, Cache) {
+  int ncall = 0;
+  auto get_fd_block_size = [&](int fd) {
+    ncall++;
+    return fd;
+  };
+  std::map<std::string, int> dir_fds{
+      {"/", 0},
+      {"/db", 1},
+      {"/db1", 2},
+      {"/db2", 3},
+  };
+  auto get_dir_block_size = [&](const std::string& dir, size_t* size) {
+    ncall++;
+    *size = dir_fds[dir];
+    return Status::OK();
+  };
+  LogicalBlockSizeCache cache(get_fd_block_size, get_dir_block_size);
+  ASSERT_EQ(0, ncall);
+  ASSERT_EQ(0, cache.Size());
+
+  ASSERT_EQ(6, cache.GetLogicalBlockSize("/sst", 6));
+  ASSERT_EQ(1, ncall);
+  ASSERT_EQ(7, cache.GetLogicalBlockSize("/db/sst1", 7));
+  ASSERT_EQ(2, ncall);
+  ASSERT_EQ(8, cache.GetLogicalBlockSize("/db/sst2", 8));
+  ASSERT_EQ(3, ncall);
+
+  ASSERT_OK(cache.RefAndCacheLogicalBlockSize({"/", "/db1/", "/db2"}));
+  ASSERT_EQ(3, cache.Size());
+  ASSERT_TRUE(cache.Contains("/"));
+  ASSERT_TRUE(cache.Contains("/db1"));
+  ASSERT_TRUE(cache.Contains("/db2"));
+  ASSERT_EQ(6, ncall);
+  // Block size for / is cached.
+  ASSERT_EQ(0, cache.GetLogicalBlockSize("/sst", 6));
+  ASSERT_EQ(6, ncall);
+  // No cached size for /db.
+  ASSERT_EQ(7, cache.GetLogicalBlockSize("/db/sst1", 7));
+  ASSERT_EQ(7, ncall);
+  ASSERT_EQ(8, cache.GetLogicalBlockSize("/db/sst2", 8));
+  ASSERT_EQ(8, ncall);
+  // Block size for /db1 is cached.
+  ASSERT_EQ(2, cache.GetLogicalBlockSize("/db1/sst1", 4));
+  ASSERT_EQ(8, ncall);
+  ASSERT_EQ(2, cache.GetLogicalBlockSize("/db1/sst2", 5));
+  ASSERT_EQ(8, ncall);
+  // Block size for /db2 is cached.
+  ASSERT_EQ(3, cache.GetLogicalBlockSize("/db2/sst1", 6));
+  ASSERT_EQ(8, ncall);
+  ASSERT_EQ(3, cache.GetLogicalBlockSize("/db2/sst2", 7));
+  ASSERT_EQ(8, ncall);
+
+  cache.RefAndCacheLogicalBlockSize({"/db"});
+  ASSERT_EQ(4, cache.Size());
+  ASSERT_TRUE(cache.Contains("/"));
+  ASSERT_TRUE(cache.Contains("/db1"));
+  ASSERT_TRUE(cache.Contains("/db2"));
+  ASSERT_TRUE(cache.Contains("/db"));
+
+  ASSERT_EQ(9, ncall);
+  // Block size for /db is cached.
+  ASSERT_EQ(1, cache.GetLogicalBlockSize("/db/sst1", 7));
+  ASSERT_EQ(9, ncall);
+  ASSERT_EQ(1, cache.GetLogicalBlockSize("/db/sst2", 8));
+  ASSERT_EQ(9, ncall);
+}
+
+// Tests the reference counting behavior.
+TEST_F(LogicalBlockSizeCacheTest, Ref) {
+  int ncall = 0;
+  auto get_fd_block_size = [&](int fd) {
+    ncall++;
+    return fd;
+  };
+  std::map<std::string, int> dir_fds{
+      {"/db", 0},
+  };
+  auto get_dir_block_size = [&](const std::string& dir, size_t* size) {
+    ncall++;
+    *size = dir_fds[dir];
+    return Status::OK();
+  };
+  LogicalBlockSizeCache cache(get_fd_block_size, get_dir_block_size);
+
+  ASSERT_EQ(0, ncall);
+
+  ASSERT_EQ(1, cache.GetLogicalBlockSize("/db/sst0", 1));
+  ASSERT_EQ(1, ncall);
+
+  cache.RefAndCacheLogicalBlockSize({"/db"});
+  ASSERT_EQ(2, ncall);
+  ASSERT_EQ(1, cache.GetRefCount("/db"));
+  // Block size for /db is cached. Ref count = 1.
+  ASSERT_EQ(0, cache.GetLogicalBlockSize("/db/sst1", 1));
+  ASSERT_EQ(2, ncall);
+
+  // Ref count = 2, but won't recompute the cached buffer size.
+  cache.RefAndCacheLogicalBlockSize({"/db"});
+  ASSERT_EQ(2, cache.GetRefCount("/db"));
+  ASSERT_EQ(2, ncall);
+
+  // Ref count = 1.
+  cache.UnrefAndTryRemoveCachedLogicalBlockSize({"/db"});
+  ASSERT_EQ(1, cache.GetRefCount("/db"));
+  // Block size for /db is still cached.
+  ASSERT_EQ(0, cache.GetLogicalBlockSize("/db/sst2", 1));
+  ASSERT_EQ(2, ncall);
+
+  // Ref count = 0 and cached buffer size for /db is removed.
+  cache.UnrefAndTryRemoveCachedLogicalBlockSize({"/db"});
+  ASSERT_EQ(0, cache.Size());
+  ASSERT_EQ(1, cache.GetLogicalBlockSize("/db/sst0", 1));
+  ASSERT_EQ(3, ncall);
+}
+#endif
+
+}  // namespace ROCKSDB_NAMESPACE
+#endif
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}

env/mock_env.h

@@ -24,75 +24,80 @@ class MockEnv : public EnvWrapper {
  public:
   explicit MockEnv(Env* base_env);
 
-  virtual ~MockEnv();
+  ~MockEnv() override;
 
   // Partial implementation of the Env interface.
-  virtual Status NewSequentialFile(const std::string& fname,
+  Status RegisterDbPaths(const std::vector<std::string>& /*paths*/) override {
+    return Status::OK();
+  }
+
+  Status UnregisterDbPaths(const std::vector<std::string>& /*paths*/) override {
+    return Status::OK();
+  }
+
+  Status NewSequentialFile(const std::string& fname,
                            std::unique_ptr<SequentialFile>* result,
                            const EnvOptions& soptions) override;
 
-  virtual Status NewRandomAccessFile(const std::string& fname,
+  Status NewRandomAccessFile(const std::string& fname,
                              std::unique_ptr<RandomAccessFile>* result,
                              const EnvOptions& soptions) override;
 
-  virtual Status NewRandomRWFile(const std::string& fname,
+  Status NewRandomRWFile(const std::string& fname,
                          std::unique_ptr<RandomRWFile>* result,
                          const EnvOptions& options) override;
 
-  virtual Status ReuseWritableFile(const std::string& fname,
+  Status ReuseWritableFile(const std::string& fname,
                            const std::string& old_fname,
                            std::unique_ptr<WritableFile>* result,
                            const EnvOptions& options) override;
 
-  virtual Status NewWritableFile(const std::string& fname,
+  Status NewWritableFile(const std::string& fname,
                          std::unique_ptr<WritableFile>* result,
                          const EnvOptions& env_options) override;
 
-  virtual Status NewDirectory(const std::string& name,
+  Status NewDirectory(const std::string& name,
                       std::unique_ptr<Directory>* result) override;
 
-  virtual Status FileExists(const std::string& fname) override;
+  Status FileExists(const std::string& fname) override;
 
-  virtual Status GetChildren(const std::string& dir,
+  Status GetChildren(const std::string& dir,
                      std::vector<std::string>* result) override;
 
   void DeleteFileInternal(const std::string& fname);
 
-  virtual Status DeleteFile(const std::string& fname) override;
+  Status DeleteFile(const std::string& fname) override;
 
-  virtual Status Truncate(const std::string& fname, size_t size) override;
+  Status Truncate(const std::string& fname, size_t size) override;
 
-  virtual Status CreateDir(const std::string& dirname) override;
+  Status CreateDir(const std::string& dirname) override;
 
-  virtual Status CreateDirIfMissing(const std::string& dirname) override;
+  Status CreateDirIfMissing(const std::string& dirname) override;
 
-  virtual Status DeleteDir(const std::string& dirname) override;
+  Status DeleteDir(const std::string& dirname) override;
 
-  virtual Status GetFileSize(const std::string& fname,
+  Status GetFileSize(const std::string& fname, uint64_t* file_size) override;
-                             uint64_t* file_size) override;
 
-  virtual Status GetFileModificationTime(const std::string& fname,
+  Status GetFileModificationTime(const std::string& fname,
                                  uint64_t* time) override;
 
-  virtual Status RenameFile(const std::string& src,
+  Status RenameFile(const std::string& src, const std::string& target) override;
-                            const std::string& target) override;
 
-  virtual Status LinkFile(const std::string& src,
+  Status LinkFile(const std::string& src, const std::string& target) override;
-                          const std::string& target) override;
 
-  virtual Status NewLogger(const std::string& fname,
+  Status NewLogger(const std::string& fname,
                    std::shared_ptr<Logger>* result) override;
 
-  virtual Status LockFile(const std::string& fname, FileLock** flock) override;
+  Status LockFile(const std::string& fname, FileLock** flock) override;
 
-  virtual Status UnlockFile(FileLock* flock) override;
+  Status UnlockFile(FileLock* flock) override;
 
-  virtual Status GetTestDirectory(std::string* path) override;
+  Status GetTestDirectory(std::string* path) override;
 
   // Results of these can be affected by FakeSleepForMicroseconds()
-  virtual Status GetCurrentTime(int64_t* unix_time) override;
+  Status GetCurrentTime(int64_t* unix_time) override;
-  virtual uint64_t NowMicros() override;
+  uint64_t NowMicros() override;
-  virtual uint64_t NowNanos() override;
+  uint64_t NowNanos() override;
 
   Status CorruptBuffer(const std::string& fname);
 

include/rocksdb/env.h

@@ -163,6 +163,15 @@ class Env {
   // The result of Default() belongs to rocksdb and must never be deleted.
   static Env* Default();
 
+  // See FileSystem::RegisterDbPaths.
+  virtual Status RegisterDbPaths(const std::vector<std::string>& /*paths*/) {
+    return Status::OK();
+  }
+  // See FileSystem::UnregisterDbPaths.
+  virtual Status UnregisterDbPaths(const std::vector<std::string>& /*paths*/) {
+    return Status::OK();
+  }
+
   // Create a brand new sequentially-readable file with the specified name.
   // On success, stores a pointer to the new file in *result and returns OK.
   // On failure stores nullptr in *result and returns non-OK.  If the file does
@@ -1155,6 +1164,14 @@ class EnvWrapper : public Env {
   Env* target() const { return target_; }
 
   // The following text is boilerplate that forwards all methods to target()
+  Status RegisterDbPaths(const std::vector<std::string>& paths) override {
+    return target_->RegisterDbPaths(paths);
+  }
+
+  Status UnregisterDbPaths(const std::vector<std::string>& paths) override {
+    return target_->UnregisterDbPaths(paths);
+  }
+
   Status NewSequentialFile(const std::string& f,
                            std::unique_ptr<SequentialFile>* r,
                            const EnvOptions& options) override {

include/rocksdb/file_system.h

@@ -171,6 +171,35 @@ class FileSystem {
   // The result of Default() belongs to rocksdb and must never be deleted.
   static std::shared_ptr<FileSystem> Default();
 
+  // Handles the event when a new DB or a new ColumnFamily starts using the
+  // specified data paths.
+  //
+  // The data paths might be shared by different DBs or ColumnFamilies,
+  // so RegisterDbPaths might be called with the same data paths.
+  // For example, when CreateColumnFamily is called multiple times with the same
+  // data path, RegisterDbPaths will also be called with the same data path.
+  //
+  // If the return status is ok, then the paths must be correspondingly
+  // called in UnregisterDbPaths;
+  // otherwise this method should have no side effect, and UnregisterDbPaths
+  // do not need to be called for the paths.
+  //
+  // Different implementations may take different actions.
+  // By default, it's a no-op and returns Status::OK.
+  virtual Status RegisterDbPaths(const std::vector<std::string>& /*paths*/) {
+    return Status::OK();
+  }
+  // Handles the event a DB or a ColumnFamily stops using the specified data
+  // paths.
+  //
+  // It should be called corresponding to each successful RegisterDbPaths.
+  //
+  // Different implementations may take different actions.
+  // By default, it's a no-op and returns Status::OK.
+  virtual Status UnregisterDbPaths(const std::vector<std::string>& /*paths*/) {
+    return Status::OK();
+  }
+
   // Create a brand new sequentially-readable file with the specified name.
   // On success, stores a pointer to the new file in *result and returns OK.
   // On failure stores nullptr in *result and returns non-OK.  If the file does

src.mk

@@ -337,6 +337,7 @@ MAIN_SOURCES =                                                          \
   db/db_tailing_iter_test.cc                                            \
   db/db_test.cc                                                         \
   db/db_test2.cc                                                        \
+  db/db_logical_block_size_cache_test.cc                                \
   db/db_universal_compaction_test.cc                                    \
   db/db_wal_test.cc                                                     \
   db/db_write_test.cc                                                   \
@@ -383,6 +384,7 @@ MAIN_SOURCES =                                                          \
   db/write_controller_test.cc                                           \
   env/env_basic_test.cc                                                 \
   env/env_test.cc                                                       \
+  env/io_posix_test.cc                                                  \
   env/mock_env_test.cc                                                  \
   logging/auto_roll_logger_test.cc                                      \
   logging/env_logger_test.cc                                            \