diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index ef3dd661a7..2cf06ba8a8 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -1578,6 +1578,7 @@ phutil_register_library_map(array(
     'PhabricatorFileUploadException' => 'applications/files/exception/PhabricatorFileUploadException.php',
     'PhabricatorFilesApplication' => 'applications/files/application/PhabricatorFilesApplication.php',
     'PhabricatorFilesConfigOptions' => 'applications/files/config/PhabricatorFilesConfigOptions.php',
+    'PhabricatorFilesManagementCompactWorkflow' => 'applications/files/management/PhabricatorFilesManagementCompactWorkflow.php',
     'PhabricatorFilesManagementEnginesWorkflow' => 'applications/files/management/PhabricatorFilesManagementEnginesWorkflow.php',
     'PhabricatorFilesManagementMigrateWorkflow' => 'applications/files/management/PhabricatorFilesManagementMigrateWorkflow.php',
     'PhabricatorFilesManagementPurgeWorkflow' => 'applications/files/management/PhabricatorFilesManagementPurgeWorkflow.php',
@@ -4430,6 +4431,7 @@ phutil_register_library_map(array(
     'PhabricatorFileUploadException' => 'Exception',
     'PhabricatorFilesApplication' => 'PhabricatorApplication',
     'PhabricatorFilesConfigOptions' => 'PhabricatorApplicationConfigOptions',
+    'PhabricatorFilesManagementCompactWorkflow' => 'PhabricatorFilesManagementWorkflow',
     'PhabricatorFilesManagementEnginesWorkflow' => 'PhabricatorFilesManagementWorkflow',
     'PhabricatorFilesManagementMigrateWorkflow' => 'PhabricatorFilesManagementWorkflow',
     'PhabricatorFilesManagementPurgeWorkflow' => 'PhabricatorFilesManagementWorkflow',
diff --git a/src/applications/files/management/PhabricatorFilesManagementCompactWorkflow.php b/src/applications/files/management/PhabricatorFilesManagementCompactWorkflow.php
new file mode 100644
index 0000000000..63f44228fe
--- /dev/null
+++ b/src/applications/files/management/PhabricatorFilesManagementCompactWorkflow.php
@@ -0,0 +1,133 @@
+<?php
+
+final class PhabricatorFilesManagementCompactWorkflow
+  extends PhabricatorFilesManagementWorkflow {
+
+  public function didConstruct() {
+    $this
+      ->setName('compact')
+      ->setSynopsis(
+        pht(
+          'Merge identical files to share the same storage. In some cases, '.
+          'this can repair files with missing data.'))
+      ->setArguments(
+        array(
+          array(
+            'name'      => 'dry-run',
+            'help'      => pht('Show what would be compacted.'),
+          ),
+          array(
+            'name'      => 'all',
+            'help'      => pht('Compact all files.'),
+          ),
+          array(
+            'name'      => 'names',
+            'wildcard'  => true,
+          ),
+        ));
+  }
+
+  public function execute(PhutilArgumentParser $args) {
+    $console = PhutilConsole::getConsole();
+
+    $iterator = $this->buildIterator($args);
+    if (!$iterator) {
+      throw new PhutilArgumentUsageException(
+        pht(
+          'Either specify a list of files to compact, or use `--all` '.
+          'to compact all files.'));
+    }
+
+    $is_dry_run = $args->getArg('dry-run');
+
+    foreach ($iterator as $file) {
+      $monogram = $file->getMonogram();
+
+      $hash = $file->getContentHash();
+      if (!$hash) {
+        $console->writeOut(
+          "%s\n",
+          pht('%s: No content hash.', $monogram));
+        continue;
+      }
+
+      // Find other files with the same content hash. We're going to point
+      // them at the data for this file.
+      $similar_files = id(new PhabricatorFile())->loadAllWhere(
+        'contentHash = %s AND id != %d AND
+          (storageEngine != %s OR storageHandle != %s)',
+        $hash,
+        $file->getID(),
+        $file->getStorageEngine(),
+        $file->getStorageHandle());
+      if (!$similar_files) {
+        $console->writeOut(
+          "%s\n",
+          pht('%s: No other files with the same content hash.', $monogram));
+        continue;
+      }
+
+      // Only compact files into this one if we can load the data. This
+      // prevents us from breaking working files if we're missing some data.
+      try {
+        $data = $file->loadFileData();
+      } catch (Exception $ex) {
+        $data = null;
+      }
+
+      if ($data === null) {
+        $console->writeOut(
+          "%s\n",
+          pht(
+            '%s: Unable to load file data; declining to compact.',
+            $monogram));
+        continue;
+      }
+
+      foreach ($similar_files as $similar_file) {
+        if ($is_dry_run) {
+          $console->writeOut(
+            "%s\n",
+            pht(
+              '%s: Would compact storage with %s.',
+              $monogram,
+              $similar_file->getMonogram()));
+          continue;
+        }
+
+        $console->writeOut(
+          "%s\n",
+          pht(
+            '%s: Compacting storage with %s.',
+            $monogram,
+            $similar_file->getMonogram()));
+
+        $old_instance = null;
+        try {
+          $old_instance = $similar_file->instantiateStorageEngine();
+          $old_engine = $similar_file->getStorageEngine();
+          $old_handle = $similar_file->getStorageHandle();
+        } catch (Exception $ex) {
+          // If the old stuff is busted, we just won't try to delete the
+          // old data.
+          phlog($ex);
+        }
+
+        $similar_file
+          ->setStorageEngine($file->getStorageEngine())
+          ->setStorageHandle($file->getStorageHandle())
+          ->save();
+
+        if ($old_instance) {
+          $similar_file->deleteFileDataIfUnused(
+            $old_instance,
+            $old_engine,
+            $old_handle);
+        }
+      }
+    }
+
+    return 0;
+  }
+
+}
diff --git a/src/applications/files/storage/PhabricatorFile.php b/src/applications/files/storage/PhabricatorFile.php
index 133da30415..44ba9ca21f 100644
--- a/src/applications/files/storage/PhabricatorFile.php
+++ b/src/applications/files/storage/PhabricatorFile.php
@@ -455,7 +455,7 @@ final class PhabricatorFile extends PhabricatorFileDAO
    * Destroy stored file data if there are no remaining files which reference
    * it.
    */
-  private function deleteFileDataIfUnused(
+  public function deleteFileDataIfUnused(
     PhabricatorFileStorageEngine $engine,
     $engine_identifier,
     $handle) {
@@ -644,7 +644,7 @@ final class PhabricatorFile extends PhabricatorFileDAO
     return $supported;
   }
 
-  protected function instantiateStorageEngine() {
+  public function instantiateStorageEngine() {
     return self::buildEngine($this->getStorageEngine());
   }