From 82ceb88998fccfdbe21d2e66cd8764adef7d55e5 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher <jakobunt@gmail.com>
Date: Sun, 22 Mar 2015 16:41:29 +0100
Subject: [PATCH] Remove "-o default_permissions" unless needed.

It is only needed when "-o allow_other" is specified.

"-o default_permissions" causes libfuse to check file access
in userspace. This costs CPU cycles and causes additional
stat() calls - libfuse has to walk up the whole path to check
for "x" permissions on directories.

This improves "make benchmark-reverse" performance
by 30% when caching is disabled. It also gives a slight
improvement with caches on.

Before:

  tests/benchmark-reverse.pl /var/tmp
  * rsync 1 (initial copy)... 12179 ms
  * rsync 2 (no changes)... 1840 ms
  cleaning up... done
  tests/benchmark-reverse.pl /var/tmp --nocache
  * rsync 1 (initial copy)... 30696 ms
  * rsync 2 (no changes)... 10552 ms
  cleaning up... done

After:

  tests/benchmark-reverse.pl /var/tmp
  * rsync 1 (initial copy)... 12095 ms
  * rsync 2 (no changes)... 1693 ms
  cleaning up... done
  tests/benchmark-reverse.pl /var/tmp --nocache
  * rsync 1 (initial copy)... 21266 ms
  * rsync 2 (no changes)... 6486 ms
  cleaning up... done
---
 encfs/main.cpp | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/encfs/main.cpp b/encfs/main.cpp
index d5e98c4..9281e60 100644
--- a/encfs/main.cpp
+++ b/encfs/main.cpp
@@ -367,13 +367,6 @@ static bool processArgs(int argc, char *argv[],
 
   if (!out->isThreaded) PUSHARG("-s");
 
-  if (useDefaultFlags) {
-    PUSHARG("-o");
-    PUSHARG("use_ino");
-    PUSHARG("-o");
-    PUSHARG("default_permissions");
-  }
-
   // we should have at least 2 arguments left over - the source directory and
   // the mount point.
   if (optind + 2 <= argc) {
@@ -396,6 +389,26 @@ static bool processArgs(int argc, char *argv[],
     }
   }
 
+  // Add default flags unless --no-default-flags was passed
+  if (useDefaultFlags) {
+
+    // Expose the underlying stable inode number
+    PUSHARG("-o");
+    PUSHARG("use_ino");
+
+    // "default_permissions" comes with a performance cost. Only enable
+    // it if makes sense.
+    for(int i=0; i < out->fuseArgc; i++) {
+      if ( out->fuseArgv[i] == NULL ) {
+        continue;
+      } else if (strcmp(out->fuseArgv[i], "allow_other") == 0) {
+        PUSHARG("-o");
+        PUSHARG("default_permissions");
+        break;
+      }
+    }
+  }
+
   // sanity check
   if (out->isDaemon && (!isAbsolutePath(out->mountPoint.c_str()) ||
                         !isAbsolutePath(out->opts->rootDir.c_str()))) {