diff --git a/db/version_set.cc b/db/version_set.cc
index 532e37361..c34fa385d 100644
--- a/db/version_set.cc
+++ b/db/version_set.cc
@@ -2413,6 +2413,7 @@ void VersionStorageInfo::PrepareForVersionAppend(
   GenerateLevelFilesBrief();
   GenerateLevel0NonOverlapping();
   GenerateBottommostFiles();
+  GenerateFileLocationIndex();
 }
 
 void Version::PrepareAppend(const MutableCFOptions& mutable_cf_options,
@@ -3046,12 +3047,6 @@ void VersionStorageInfo::AddFile(int level, FileMetaData* f) {
   level_files.push_back(f);
 
   f->refs++;
-
-  const uint64_t file_number = f->fd.GetNumber();
-
-  assert(file_locations_.find(file_number) == file_locations_.end());
-  file_locations_.emplace(file_number,
-                          FileLocation(level, level_files.size() - 1));
 }
 
 void VersionStorageInfo::AddBlobFile(
@@ -3286,6 +3281,28 @@ void VersionStorageInfo::GenerateBottommostFiles() {
   }
 }
 
+void VersionStorageInfo::GenerateFileLocationIndex() {
+  size_t num_files = 0;
+
+  for (int level = 0; level < num_levels_; ++level) {
+    num_files += files_[level].size();
+  }
+
+  file_locations_.reserve(num_files);
+
+  for (int level = 0; level < num_levels_; ++level) {
+    for (size_t pos = 0; pos < files_[level].size(); ++pos) {
+      const FileMetaData* const meta = files_[level][pos];
+      assert(meta);
+
+      const uint64_t file_number = meta->fd.GetNumber();
+
+      assert(file_locations_.find(file_number) == file_locations_.end());
+      file_locations_.emplace(file_number, FileLocation(level, pos));
+    }
+  }
+}
+
 void VersionStorageInfo::UpdateOldestSnapshot(SequenceNumber seqnum) {
   assert(seqnum >= oldest_snapshot_seqnum_);
   oldest_snapshot_seqnum_ = seqnum;
diff --git a/db/version_set.h b/db/version_set.h
index 53f97012d..ce55e755d 100644
--- a/db/version_set.h
+++ b/db/version_set.h
@@ -302,7 +302,7 @@ class VersionStorageInfo {
     size_t position_ = 0;
   };
 
-  // REQUIRES: This version has been saved (see VersionSet::SaveTo)
+  // REQUIRES: PrepareForVersionAppend has been called
   FileLocation GetFileLocation(uint64_t file_number) const {
     const auto it = file_locations_.find(file_number);
 
@@ -319,7 +319,7 @@ class VersionStorageInfo {
     return it->second;
   }
 
-  // REQUIRES: This version has been saved (see VersionSet::SaveTo)
+  // REQUIRES: PrepareForVersionAppend has been called
   FileMetaData* GetFileMetaDataByNumber(uint64_t file_number) const {
     auto location = GetFileLocation(file_number);
 
@@ -520,6 +520,7 @@ class VersionStorageInfo {
   void GenerateLevelFilesBrief();
   void GenerateLevel0NonOverlapping();
   void GenerateBottommostFiles();
+  void GenerateFileLocationIndex();
 
   const InternalKeyComparator* internal_comparator_;
   const Comparator* user_comparator_;