Improvements to Env::GetChildren (#7819)

Summary:
The main improvement here is to not include `.` or `..` in the results of `Env::GetChildren`. The occurrence of `.` or `..`; it is non-portable, dependent on the Operating System and the File System. See: https://www.gnu.org/software/libc/manual/html_node/Reading_002fClosing-Directory.html

There were lots of duplicate checks spread through the RocksDB codebase previously to skip `.` and `..`. This new removes the need for those at the source.

Also some minor fixes to `Env::GetChildren`:
* Improve error handling in POSIX implementation
* Remove unnecessary array allocation on Windows
* Fix struct name for Windows Non-UTF-8 API

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7819

Reviewed By: ajkr

Differential Revision: D25837394

Pulled By: jay-zhuang

fbshipit-source-id: 1e137e7218d38b450af9c083f73d5357abcbba2e

HISTORY.md

@@ -30,6 +30,7 @@
 
 ### Public API Change
 * Deprecated public but rarely-used FilterBitsBuilder::CalculateNumEntry, which is replaced with ApproximateNumEntries taking a size_t parameter and returning size_t.
+* To improve portability the functions `Env::GetChildren` and `Env::GetChildrenFileAttributes` will no longer return entries for the special directories `.` or `..`.
 
 ## 6.15.0 (11/13/2020)
 ### Bug Fixes

db/column_family_test.cc

@@ -898,9 +898,7 @@ TEST_P(ColumnFamilyTest, IgnoreRecoveredLog) {
   std::vector<std::string> old_files;
   ASSERT_OK(env_->GetChildren(backup_logs, &old_files));
   for (auto& file : old_files) {
-    if (file != "." && file != "..") {
+    ASSERT_OK(env_->DeleteFile(backup_logs + "/" + file));
-      ASSERT_OK(env_->DeleteFile(backup_logs + "/" + file));
-    }
   }
 
   column_family_options_.merge_operator =
@@ -929,9 +927,7 @@ TEST_P(ColumnFamilyTest, IgnoreRecoveredLog) {
   std::vector<std::string> logs;
   ASSERT_OK(env_->GetChildren(db_options_.wal_dir, &logs));
   for (auto& log : logs) {
-    if (log != ".." && log != ".") {
+    CopyFile(db_options_.wal_dir + "/" + log, backup_logs + "/" + log);
-      CopyFile(db_options_.wal_dir + "/" + log, backup_logs + "/" + log);
-    }
   }
 
   // recover the DB
@@ -956,9 +952,7 @@ TEST_P(ColumnFamilyTest, IgnoreRecoveredLog) {
     if (iter == 0) {
       // copy the logs from backup back to wal dir
       for (auto& log : logs) {
-        if (log != ".." && log != ".") {
+        CopyFile(backup_logs + "/" + log, db_options_.wal_dir + "/" + log);
-          CopyFile(backup_logs + "/" + log, db_options_.wal_dir + "/" + log);
-        }
       }
     }
   }

db/db_encryption_test.cc

@@ -44,7 +44,7 @@ TEST_F(DBEncryptionTest, CheckEncrypted) {
   Env* target = GetTargetEnv();
   int hits = 0;
   for (auto it = fileNames.begin() ; it != fileNames.end(); ++it) {
-    if ((*it == "..") || (*it == ".") || (*it == "LOCK")) {
+    if (*it == "LOCK") {
       continue;
     }
     auto filePath = dbname_ + "/" + *it;

db/db_test2.cc

@@ -41,9 +41,7 @@ TEST_F(DBTest2, OpenForReadOnly) {
   std::vector<std::string> files;
   ASSERT_OK(env_->GetChildren(dbname, &files));
   for (auto& f : files) {
-    if (f != "." && f != "..") {
+    ASSERT_OK(env_->DeleteFile(dbname + "/" + f));
-      ASSERT_OK(env_->DeleteFile(dbname + "/" + f));
-    }
   }
   // <dbname> should be empty now and we should be able to delete it
   ASSERT_OK(env_->DeleteDir(dbname));
@@ -75,9 +73,7 @@ TEST_F(DBTest2, OpenForReadOnlyWithColumnFamilies) {
   std::vector<std::string> files;
   ASSERT_OK(env_->GetChildren(dbname, &files));
   for (auto& f : files) {
-    if (f != "." && f != "..") {
+    ASSERT_OK(env_->DeleteFile(dbname + "/" + f));
-      ASSERT_OK(env_->DeleteFile(dbname + "/" + f));
-    }
   }
   // <dbname> should be empty now and we should be able to delete it
   ASSERT_OK(env_->DeleteDir(dbname));

db/db_wal_test.cc

@@ -506,9 +506,7 @@ TEST_F(DBWALTest, IgnoreRecoveredLog) {
     std::vector<std::string> old_files;
     ASSERT_OK(env_->GetChildren(backup_logs, &old_files));
     for (auto& file : old_files) {
-      if (file != "." && file != "..") {
+      ASSERT_OK(env_->DeleteFile(backup_logs + "/" + file));
-        ASSERT_OK(env_->DeleteFile(backup_logs + "/" + file));
-      }
     }
     Options options = CurrentOptions();
     options.create_if_missing = true;
@@ -528,9 +526,7 @@ TEST_F(DBWALTest, IgnoreRecoveredLog) {
     std::vector<std::string> logs;
     ASSERT_OK(env_->GetChildren(options.wal_dir, &logs));
     for (auto& log : logs) {
-      if (log != ".." && log != ".") {
+      CopyFile(options.wal_dir + "/" + log, backup_logs + "/" + log);
-        CopyFile(options.wal_dir + "/" + log, backup_logs + "/" + log);
-      }
     }
 
     // recover the DB
@@ -541,9 +537,7 @@ TEST_F(DBWALTest, IgnoreRecoveredLog) {
 
     // copy the logs from backup back to wal dir
     for (auto& log : logs) {
-      if (log != ".." && log != ".") {
+      CopyFile(backup_logs + "/" + log, options.wal_dir + "/" + log);
-        CopyFile(backup_logs + "/" + log, options.wal_dir + "/" + log);
-      }
     }
     // this should ignore the log files, recovery should not happen again
     // if the recovery happens, the same merge operator would be called twice,
@@ -559,9 +553,7 @@ TEST_F(DBWALTest, IgnoreRecoveredLog) {
     // copy the logs from backup back to wal dir
     ASSERT_OK(env_->CreateDirIfMissing(options.wal_dir));
     for (auto& log : logs) {
-      if (log != ".." && log != ".") {
+      CopyFile(backup_logs + "/" + log, options.wal_dir + "/" + log);
-        CopyFile(backup_logs + "/" + log, options.wal_dir + "/" + log);
-      }
     }
     // assert that we successfully recovered only from logs, even though we
     // destroyed the DB
@@ -574,11 +566,9 @@ TEST_F(DBWALTest, IgnoreRecoveredLog) {
     // copy the logs from backup back to wal dir
     ASSERT_OK(env_->CreateDirIfMissing(options.wal_dir));
     for (auto& log : logs) {
-      if (log != ".." && log != ".") {
+      CopyFile(backup_logs + "/" + log, options.wal_dir + "/" + log);
-        CopyFile(backup_logs + "/" + log, options.wal_dir + "/" + log);
+      // we won't be needing this file no more
-        // we won't be needing this file no more
+      ASSERT_OK(env_->DeleteFile(backup_logs + "/" + log));
-        ASSERT_OK(env_->DeleteFile(backup_logs + "/" + log));
-      }
     }
     Status s = TryReopen(options);
     ASSERT_NOK(s);

env/env_basic_test.cc

@@ -10,6 +10,7 @@
 #include <vector>
 
 #include "env/mock_env.h"
+#include "file/file_util.h"
 #include "rocksdb/convenience.h"
 #include "rocksdb/env.h"
 #include "rocksdb/env_encryption.h"
@@ -17,46 +18,6 @@
 
 namespace ROCKSDB_NAMESPACE {
 
-// Normalizes trivial differences across Envs such that these test cases can
-// run on all Envs.
-class NormalizingEnvWrapper : public EnvWrapper {
- private:
-  std::unique_ptr<Env> base_;
-
- public:
-  explicit NormalizingEnvWrapper(std::unique_ptr<Env>&& base)
-      : EnvWrapper(base.get()), base_(std::move(base)) {}
-  explicit NormalizingEnvWrapper(Env* base) : EnvWrapper(base) {}
-
-  // Removes . and .. from directory listing
-  Status GetChildren(const std::string& dir,
-                     std::vector<std::string>* result) override {
-    Status status = EnvWrapper::GetChildren(dir, result);
-    if (status.ok()) {
-      result->erase(std::remove_if(result->begin(), result->end(),
-                                   [](const std::string& s) {
-                                     return s == "." || s == "..";
-                                   }),
-                    result->end());
-    }
-    return status;
-  }
-
-  // Removes . and .. from directory listing
-  Status GetChildrenFileAttributes(
-      const std::string& dir, std::vector<FileAttributes>* result) override {
-    Status status = EnvWrapper::GetChildrenFileAttributes(dir, result);
-    if (status.ok()) {
-      result->erase(std::remove_if(result->begin(), result->end(),
-                                   [](const FileAttributes& fa) {
-                                     return fa.name == "." || fa.name == "..";
-                                   }),
-                    result->end());
-    }
-    return status;
-  }
-};
-
 class EnvBasicTestWithParam : public testing::Test,
                               public ::testing::WithParamInterface<Env*> {
  public:
@@ -68,32 +29,17 @@ class EnvBasicTestWithParam : public testing::Test,
     test_dir_ = test::PerThreadDBPath(env_, "env_basic_test");
   }
 
-  void SetUp() override {
+  void SetUp() override { ASSERT_OK(env_->CreateDirIfMissing(test_dir_)); }
-    env_->CreateDirIfMissing(test_dir_).PermitUncheckedError();
-  }
 
-  void TearDown() override {
+  void TearDown() override { ASSERT_OK(DestroyDir(env_, test_dir_)); }
-    std::vector<std::string> files;
-    env_->GetChildren(test_dir_, &files).PermitUncheckedError();
-    for (const auto& file : files) {
-      // don't know whether it's file or directory, try both. The tests must
-      // only create files or empty directories, so one must succeed, else the
-      // directory's corrupted.
-      Status s = env_->DeleteFile(test_dir_ + "/" + file);
-      if (!s.ok()) {
-        ASSERT_OK(env_->DeleteDir(test_dir_ + "/" + file));
-      }
-    }
-  }
 };
 
 class EnvMoreTestWithParam : public EnvBasicTestWithParam {};
 
-static std::unique_ptr<Env> def_env(new NormalizingEnvWrapper(Env::Default()));
 INSTANTIATE_TEST_CASE_P(EnvDefault, EnvBasicTestWithParam,
-                        ::testing::Values(def_env.get()));
+                        ::testing::Values(Env::Default()));
 INSTANTIATE_TEST_CASE_P(EnvDefault, EnvMoreTestWithParam,
-                        ::testing::Values(def_env.get()));
+                        ::testing::Values(Env::Default()));
 
 static std::unique_ptr<Env> mock_env(new MockEnv(Env::Default()));
 INSTANTIATE_TEST_CASE_P(MockEnv, EnvBasicTestWithParam,
@@ -104,8 +50,7 @@ static Env* NewTestEncryptedEnv(Env* base, const std::string& provider_id) {
   std::shared_ptr<EncryptionProvider> provider;
   EXPECT_OK(EncryptionProvider::CreateFromString(ConfigOptions(), provider_id,
                                                  &provider));
-  std::unique_ptr<Env> encrypted(NewEncryptedEnv(base, provider));
+  return NewEncryptedEnv(base, provider);
-  return new NormalizingEnvWrapper(std::move(encrypted));
 }
 
 // next statements run env test against default encryption code.
@@ -374,6 +319,32 @@ TEST_P(EnvMoreTestWithParam, GetChildren) {
   ASSERT_EQ(0U, children.size());
 }
 
+TEST_P(EnvMoreTestWithParam, GetChildrenIgnoresDotAndDotDot) {
+  auto* env = Env::Default();
+  ASSERT_OK(env->CreateDirIfMissing(test_dir_));
+
+  // Create a single file
+  std::string path = test_dir_;
+  const EnvOptions soptions;
+#ifdef OS_WIN
+  path.append("\\test_file");
+#else
+  path.append("/test_file");
+#endif
+  std::string data("test data");
+  std::unique_ptr<WritableFile> file;
+  ASSERT_OK(env->NewWritableFile(path, &file, soptions));
+  ASSERT_OK(file->Append("test data"));
+
+  // get the children
+  std::vector<std::string> result;
+  ASSERT_OK(env->GetChildren(test_dir_, &result));
+
+  // expect only one file named `test_data`, i.e. no `.` or `..` names
+  ASSERT_EQ(result.size(), 1);
+  ASSERT_EQ(result.at(0), "test_file");
+}
+
 }  // namespace ROCKSDB_NAMESPACE
 int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);

env/fs_posix.cc

@@ -607,6 +607,7 @@ class PosixFileSystem : public FileSystem {
                        std::vector<std::string>* result,
                        IODebugContext* /*dbg*/) override {
     result->clear();
+
     DIR* d = opendir(dir.c_str());
     if (d == nullptr) {
       switch (errno) {
@@ -618,11 +619,34 @@ class PosixFileSystem : public FileSystem {
           return IOError("While opendir", dir, errno);
       }
     }
+
+    const auto pre_read_errno = errno;  // errno may be modified by readdir
     struct dirent* entry;
-    while ((entry = readdir(d)) != nullptr) {
+    while ((entry = readdir(d)) != nullptr && errno == pre_read_errno) {
-      result->push_back(entry->d_name);
+      // filter out '.' and '..' directory entries
+      // which appear only on some platforms
+      const bool ignore =
+          entry->d_type == DT_DIR &&
+          (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0);
+      if (!ignore) {
+        result->push_back(entry->d_name);
+      }
     }
-    closedir(d);
+
+    // always attempt to close the dir
+    const auto pre_close_errno = errno;  // errno may be modified by closedir
+    const int close_result = closedir(d);
+
+    if (pre_close_errno != pre_read_errno) {
+      // error occured during readdir
+      return IOError("While readdir", dir, pre_close_errno);
+    }
+
+    if (close_result != 0) {
+      // error occured during closedir
+      return IOError("While closedir", dir, errno);
+    }
+
     return IOStatus::OK();
   }
 

file/delete_scheduler_test.cc

@@ -57,7 +57,7 @@ class DeleteSchedulerTest : public testing::Test {
 
     int normal_cnt = 0;
     for (auto& f : files_in_dir) {
-      if (!DeleteScheduler::IsTrashFile(f) && f != "." && f != "..") {
+      if (!DeleteScheduler::IsTrashFile(f)) {
         normal_cnt++;
       }
     }

file/file_util.cc

@@ -230,9 +230,6 @@ Status DestroyDir(Env* env, const std::string& dir) {
   s = env->GetChildren(dir, &files_in_dir);
   if (s.ok()) {
     for (auto& file_in_dir : files_in_dir) {
-      if (file_in_dir == "." || file_in_dir == "..") {
-        continue;
-      }
       std::string path = dir + "/" + file_in_dir;
       bool is_dir = false;
       s = env->IsDirectory(path, &is_dir);

file/sst_file_manager_impl.cc

@@ -510,10 +510,6 @@ SstFileManager* NewSstFileManager(Env* env, std::shared_ptr<FileSystem> fs,
     s = fs->GetChildren(trash_dir, IOOptions(), &files_in_trash, nullptr);
     if (s.ok()) {
       for (const std::string& trash_file : files_in_trash) {
-        if (trash_file == "." || trash_file == "..") {
-          continue;
-        }
-
         std::string path_in_trash = trash_dir + "/" + trash_file;
         res->OnAddFile(path_in_trash);
         Status file_delete =

include/rocksdb/env.h

@@ -283,7 +283,8 @@ class Env {
   virtual Status FileExists(const std::string& fname) = 0;
 
   // Store in *result the names of the children of the specified directory.
-  // The names are relative to "dir".
+  // The names are relative to "dir", and shall never include the
+  // names `.` or `..`.
   // Original contents of *results are dropped.
   // Returns OK if "dir" exists and "*result" contains its children.
   //         NotFound if "dir" does not exist, the calling process does not have
@@ -296,7 +297,8 @@ class Env {
   // In case the implementation lists the directory prior to iterating the files
   // and files are concurrently deleted, the deleted files will be omitted from
   // result.
-  // The name attributes are relative to "dir".
+  // The name attributes are relative to "dir", and shall never include the
+  // names `.` or `..`.
   // Original contents of *results are dropped.
   // Returns OK if "dir" exists and "*result" contains its children.
   //         NotFound if "dir" does not exist, the calling process does not have

port/win/env_win.cc

@@ -645,7 +645,6 @@ IOStatus WinFileSystem::GetChildren(const std::string& dir,
                                     IODebugContext* /*dbg*/) {
   IOStatus status;
   result->clear();
-  std::vector<std::string> output;
 
   RX_WIN32_FIND_DATA data;
   memset(&data, 0, sizeof(data));
@@ -677,16 +676,20 @@ IOStatus WinFileSystem::GetChildren(const std::string& dir,
 
   UniqueFindClosePtr fc(handle, FindCloseFunc);
 
-  if (result->capacity() > 0) {
-    output.reserve(result->capacity());
-  }
-
   // For safety
   data.cFileName[MAX_PATH - 1] = 0;
 
   while (true) {
-    auto x = RX_FILESTRING(data.cFileName, RX_FNLEN(data.cFileName));
+    // filter out '.' and '..' directory entries
-    output.emplace_back(FN_TO_RX(x));
+    // which appear only on some platforms
+    const bool ignore =
+        ((data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0) &&
+        (strcmp(data.cFileName, ".") == 0 || strcmp(data.cFileName, "..") == 0);
+    if (!ignore) {
+      auto x = RX_FILESTRING(data.cFileName, RX_FNLEN(data.cFileName));
+      result->push_back(FN_TO_RX(x));
+    }
+
     BOOL ret = -RX_FindNextFile(handle, &data);
     // If the function fails the return value is zero
     // and non-zero otherwise. Not TRUE or FALSE.
@@ -696,7 +699,6 @@ IOStatus WinFileSystem::GetChildren(const std::string& dir,
     }
     data.cFileName[MAX_PATH - 1] = 0;
   }
-  output.swap(*result);
   return status;
 }
 

port/win/port_win.h

@@ -388,7 +388,7 @@ extern void SetCpuPriority(ThreadId id, CpuPriority priority);
 #define RX_FindFirstFileEx FindFirstFileExA
 #define RX_CreateDirectory CreateDirectoryA
 #define RX_FindNextFile FindNextFileA
-#define RX_WIN32_FIND_DATA WIN32_FIND_DATA
+#define RX_WIN32_FIND_DATA WIN32_FIND_DATAA
 #define RX_CreateDirectory CreateDirectoryA
 #define RX_RemoveDirectory RemoveDirectoryA
 #define RX_GetFileAttributesEx GetFileAttributesExA

utilities/backupable/backupable_db.cc

@@ -743,9 +743,6 @@ Status BackupEngineImpl::Initialize() {
   }
   // create backups_ structure
   for (auto& file : backup_meta_files) {
-    if (file == "." || file == "..") {
-      continue;
-    }
     ROCKS_LOG_INFO(options_.info_log, "Detected backup %s", file.c_str());
     BackupID backup_id = 0;
     sscanf(file.c_str(), "%u", &backup_id);
@@ -1985,9 +1982,6 @@ Status BackupEngineImpl::GarbageCollect() {
       }
     }
     for (auto& child : shared_children) {
-      if (child == "." || child == "..") {
-        continue;
-      }
       std::string rel_fname;
       if (with_checksum) {
         rel_fname = GetSharedFileWithChecksumRel(child);
@@ -2024,10 +2018,6 @@ Status BackupEngineImpl::GarbageCollect() {
     }
   }
   for (auto& child : private_children) {
-    if (child == "." || child == "..") {
-      continue;
-    }
-
     BackupID backup_id = 0;
     bool tmp_dir = child.find(".tmp") != std::string::npos;
     sscanf(child.c_str(), "%u", &backup_id);
@@ -2042,9 +2032,6 @@ Status BackupEngineImpl::GarbageCollect() {
     std::vector<std::string> subchildren;
     if (backup_env_->GetChildren(full_private_path, &subchildren).ok()) {
       for (auto& subchild : subchildren) {
-        if (subchild == "." || subchild == "..") {
-          continue;
-        }
         Status s = backup_env_->DeleteFile(full_private_path + subchild);
         ROCKS_LOG_INFO(options_.info_log, "Deleting %s -- %s",
                        (full_private_path + subchild).c_str(),

utilities/backupable/backupable_db_test.cc

@@ -417,11 +417,9 @@ class FileManager : public EnvWrapper {
     assert(fname != nullptr);
     while (true) {
       int i = rnd_.Next() % children.size();
-      if (children[i].name != "." && children[i].name != "..") {
+      fname->assign(dir + "/" + children[i].name);
-        fname->assign(dir + "/" + children[i].name);
+      *fsize = children[i].size_bytes;
-        *fsize = children[i].size_bytes;
+      return Status::OK();
-        return Status::OK();
-      }
     }
     // should never get here
     assert(false);
@@ -433,14 +431,10 @@ class FileManager : public EnvWrapper {
     Status s = GetChildren(dir, &children);
     if (!s.ok()) {
       return s;
-    } else if (children.size() <= 2) {  // . and ..
-      return Status::NotFound("");
     }
     while (true) {
       int i = rnd_.Next() % children.size();
-      if (children[i] != "." && children[i] != "..") {
+      return DeleteFile(dir + "/" + children[i]);
-        return DeleteFile(dir + "/" + children[i]);
-      }
     }
     // should never get here
     assert(false);
@@ -453,14 +447,10 @@ class FileManager : public EnvWrapper {
     Status s = GetChildren(dir, &children);
     if (!s.ok()) {
       return s;
-    } else if (children.size() <= 2) {
-      return Status::NotFound("");
     }
     while (true) {
       int i = rnd_.Next() % children.size();
-      if (children[i] != "." && children[i] != "..") {
+      return WriteToFile(dir + "/" + children[i], data);
-        return WriteToFile(dir + "/" + children[i], data);
-      }
     }
     // should never get here
     assert(false);
@@ -828,9 +818,6 @@ class BackupableDBTest : public testing::Test {
     ASSERT_OK(file_manager_->GetChildrenFileAttributes(dir, &children));
     int found_count = 0;
     for (const auto& child : children) {
-      if (child.name == "." || child.name == "..") {
-        continue;
-      }
       const std::string match("match");
       ASSERT_EQ(match, std::regex_replace(child.name, pattern, match));
       ++found_count;
@@ -844,9 +831,6 @@ class BackupableDBTest : public testing::Test {
     ASSERT_OK(file_manager_->GetChildrenFileAttributes(dir, &children));
     int found_count = 0;
     for (const auto& child : children) {
-      if (child.name == "." || child.name == "..") {
-        continue;
-      }
       auto last_underscore = child.name.find_last_of('_');
       auto last_dot = child.name.find_last_of('.');
       ASSERT_NE(child.name, child.name.substr(0, last_underscore));
@@ -1351,7 +1335,7 @@ TEST_F(BackupableDBTest, CorruptFileMaintainSize) {
   const std::string dir = backupdir_ + "/shared_checksum";
   ASSERT_OK(file_manager_->GetChildrenFileAttributes(dir, &children));
   for (const auto& child : children) {
-    if (child.name == "." || child.name == ".." || child.size_bytes == 0) {
+    if (child.size_bytes == 0) {
       continue;
     }
     // corrupt the file by replacing its content by file_size random bytes
@@ -1575,7 +1559,7 @@ TEST_F(BackupableDBTest, FlushCompactDuringBackupCheckpoint) {
       const std::string dir = backupdir_ + "/shared_checksum";
       ASSERT_OK(file_manager_->GetChildrenFileAttributes(dir, &children));
       for (const auto& child : children) {
-        if (child.name == "." || child.name == ".." || child.size_bytes == 0) {
+        if (child.size_bytes == 0) {
           continue;
         }
         const std::string match("match");
@@ -2061,7 +2045,7 @@ TEST_F(BackupableDBTest, FileSizeForIncremental) {
 
     // Corrupt backup SST
     ASSERT_OK(file_manager_->GetChildrenFileAttributes(shared_dir, &children));
-    ASSERT_EQ(children.size(), 3U);  // ".", "..", one sst
+    ASSERT_EQ(children.size(), 1U);  // one sst
     for (const auto& child : children) {
       if (child.name.size() > 4 && child.size_bytes > 0) {
         ASSERT_OK(
@@ -2121,7 +2105,7 @@ TEST_F(BackupableDBTest, FileSizeForIncremental) {
     // Count backup SSTs
     children.clear();
     ASSERT_OK(file_manager_->GetChildrenFileAttributes(shared_dir, &children));
-    ASSERT_EQ(children.size(), 4U);  // ".", "..", two sst
+    ASSERT_EQ(children.size(), 2U);  // two sst
 
     // Try create backup 3
     s = backup_engine_->CreateNewBackup(db_.get(), true /*flush*/);
@@ -2134,18 +2118,18 @@ TEST_F(BackupableDBTest, FileSizeForIncremental) {
       // Acceptable to call it corruption if size is not in name and
       // db session id collision is practically impossible.
       EXPECT_TRUE(s.IsCorruption());
-      EXPECT_EQ(children.size(), 4U);  // no SST added
+      EXPECT_EQ(children.size(), 2U);  // no SST added
     } else if (option == share_no_checksum) {
       // Good to call it corruption if both backups cannot be
       // accommodated.
       EXPECT_TRUE(s.IsCorruption());
-      EXPECT_EQ(children.size(), 4U);  // no SST added
+      EXPECT_EQ(children.size(), 2U);  // no SST added
     } else {
       // Since opening a DB seems sufficient for detecting size corruption
       // on the DB side, this should be a good thing, ...
       EXPECT_OK(s);
       // ... as long as we did actually treat it as a distinct SST file.
-      EXPECT_EQ(children.size(), 5U);  // Another SST added
+      EXPECT_EQ(children.size(), 3U);  // Another SST added
     }
     CloseDBAndBackupEngine();
     ASSERT_OK(DestroyDB(dbname_, options_));

utilities/checkpoint/checkpoint_test.cc

@@ -325,13 +325,7 @@ TEST_F(CheckpointTest, ExportColumnFamilyWithLinks) {
     ASSERT_EQ(metadata.files.size(), num_files_expected);
     std::vector<std::string> subchildren;
     ASSERT_OK(env_->GetChildren(export_path_, &subchildren));
-    int num_children = 0;
+    ASSERT_EQ(subchildren.size(), num_files_expected);
-    for (const auto& child : subchildren) {
-      if (child != "." && child != "..") {
-        ++num_children;
-      }
-    }
-    ASSERT_EQ(num_children, num_files_expected);
   };
 
   // Test DefaultColumnFamily

utilities/persistent_cache/persistent_cache_test.cc

@@ -14,6 +14,7 @@
 #include <memory>
 #include <thread>
 
+#include "file/file_util.h"
 #include "utilities/persistent_cache/block_cache_tier.h"
 
 namespace ROCKSDB_NAMESPACE {
@@ -38,30 +39,9 @@ static void OnOpenForWrite(void* arg) {
 }
 #endif
 
-static void RemoveDirectory(const std::string& folder) {
-  std::vector<std::string> files;
-  Status status = Env::Default()->GetChildren(folder, &files);
-  if (!status.ok()) {
-    // we assume the directory does not exist
-    return;
-  }
-
-  // cleanup files with the patter :digi:.rc
-  for (auto file : files) {
-    if (file == "." || file == "..") {
-      continue;
-    }
-    status = Env::Default()->DeleteFile(folder + "/" + file);
-    assert(status.ok());
-  }
-
-  status = Env::Default()->DeleteDir(folder);
-  assert(status.ok());
-}
-
 static void OnDeleteDir(void* arg) {
   char* dir = static_cast<char*>(arg);
-  RemoveDirectory(std::string(dir));
+  ASSERT_OK(DestroyDir(Env::Default(), std::string(dir)));
 }
 
 //