From 1b03fad9aa7e51bb30911af192f0d4eaa859dcc2 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Tue, 18 Nov 2014 13:37:21 +0000
Subject: [PATCH] v2v: Don't change Augeas device entries unless the value has
 changed.

When remapping block devices, don't change an entry unless its value
has changed.  This avoids unnecessary Augeas writes.

(cherry picked from commit 4c7026fb7a7514838a01771abb4c7e62a4e4485f)
---
 v2v/convert_linux.ml | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/v2v/convert_linux.ml b/v2v/convert_linux.ml
index 48f351c..44b6c7f 100644
--- a/v2v/convert_linux.ml
+++ b/v2v/convert_linux.ml
@@ -1332,7 +1332,7 @@ let rec convert ~verbose ~keep_serial_console (g : G.guestfs) inspect source =
       fun path ->
         let value = g#aug_get path in
 
-        let value =
+        let new_value =
           (* Handle grub2 resume=<dev> specially. *)
           if string_find path "GRUB_CMDLINE" >= 0 then (
             if Str.string_match rex_resume value 0 then (
@@ -1346,8 +1346,10 @@ let rec convert ~verbose ~keep_serial_console (g : G.guestfs) inspect source =
           )
           else replace_if_device path value in
 
-        g#aug_set path value;
-        changed := true
+        if value <> new_value then (
+          g#aug_set path new_value;
+          changed := true
+        )
     ) paths;
 
     if !changed then (
-- 
1.8.3.1