diff --git a/.babelrc b/.babelrc
index b0b9a96..2c63c08 100644
--- a/.babelrc
+++ b/.babelrc
@@ -1,3 +1,2 @@
 {
-  "stage": 0
 }
diff --git a/README.md b/README.md
index 6e1a472..f66141e 100644
--- a/README.md
+++ b/README.md
@@ -67,6 +67,18 @@ To get live reload working properly, you should add the following `<script>` in
 
 Make sure to update the port number in the script above accordingly to the port specified.
 
+### onUpdateCallback (default: `undefined`)
+
+Allows you to define a function to get called _after_ metalsmith has reloaded all the files. If a function is passed, this will be called with the updated files and all options passed.
+
+```javascript
+{
+  onUpdateCallback: function (files, options) {
+    // Called on every rebuild
+  }
+}
+```
+
 ### log (default: `function(...args) { console.log(prefix, ...args)}`)
 
 Function used to display the logs.
diff --git a/src/index.es b/src/index.es
index 2f9d1c3..0080053 100644
--- a/src/index.es
+++ b/src/index.es
@@ -2,6 +2,7 @@ import {
   relative as relativePath,
   resolve as resolvePath,
   isAbsolute as isAbsolutePath,
+  normalize as normalizePath
 } from "path"
 
 import async from "async"
@@ -48,6 +49,12 @@ function livereloadFiles(livereload, files, options) {
   }
 }
 
+function runOnUpdateCallback(onUpdateCallback, files, options) {
+  if (onUpdateCallback) {
+    onUpdateCallback(files, options);
+  }
+}
+
 // metalsmith-collections fix: collections are mutable
 // fuck mutability
 function backupCollections(collections) {
@@ -75,8 +82,15 @@ function updateCollections(metalsmith, collections) {
 }
 
 // metalsmith-collections fix: helps to update fix collections
-function saveFilenameInFilesData(files) {
+function saveFilenameInFilesData(metalsmith, files, options) {
   addFilenames(files)
+//   const relativeRoot = options.relativeRoot ? options.relativeRoot : metalsmith.source();
+//   Object.keys(files).forEach(filename => {
+//     if (!files[filename].filename) {
+// console.log('svaing.... ', normalizePath(relativePath(relativeRoot, filename)))
+//       files[filename].filename = normalizePath(relativePath(relativeRoot, filename))
+//     }
+//   })
 }
 
 // metalsmith-collections fix: remove items from collections that will be readded by the partial build
@@ -96,7 +110,7 @@ function removeFilesFromCollection(files, collections) {
   })
 }
 
-function runAndUpdate(metalsmith, files, livereload, options, previousFilesMap) {
+function runAndUpdate(metalsmith, files, livereload, onUpdateCallback, options, previousFilesMap) {
   // metalsmith-collections fix: metalsmith-collections plugin add files to
   // collection when run() is called which create problem since we use run()
   // with only new files.
@@ -106,7 +120,7 @@ function runAndUpdate(metalsmith, files, livereload, options, previousFilesMap)
   // (file already in the collections)
   // we iterate on collections with reference to previous files data
   // and skip old files that match the paths that will be updated
-  saveFilenameInFilesData(files)
+  saveFilenameInFilesData(metalsmith, files, options)
   const collections = metalsmith.metadata().collections
   const collectionsBackup = backupCollections(collections)
   if (collections) {
@@ -133,7 +147,6 @@ function runAndUpdate(metalsmith, files, livereload, options, previousFilesMap)
       return
     }
 
-
     // metalsmith-collections fix:  update ref for future tests
     Object.keys(freshFiles).forEach(path => {
       previousFilesMap[path] = freshFiles[path]
@@ -143,12 +156,14 @@ function runAndUpdate(metalsmith, files, livereload, options, previousFilesMap)
       if(writeErr) {throw writeErr}
 
       livereloadFiles(livereload, freshFiles, options)
+      runOnUpdateCallback(onUpdateCallback, freshFiles, options)
     })
   })
 }
 
-function buildFiles(metalsmith, paths, livereload, options, previousFilesMap) {
+function buildFiles(metalsmith, paths, livereload, onUpdateCallback, options, previousFilesMap) {
   const files = {}
+  const metadata = metalsmith.metadata();
   async.each(
     paths,
     (path, cb) => {
@@ -158,7 +173,18 @@ function buildFiles(metalsmith, paths, livereload, options, previousFilesMap) {
           return
         }
 
-        files[path] = file
+        if (metadata && metadata.permalinkMapping) {
+          const originalFilename = metadata.permalinkMapping[path];
+          if (originalFilename && previousFilesMap[originalFilename]) {
+            file = Object.assign({}, previousFilesMap[originalFilename], file);
+            file[originalFilename] = file
+          } else {
+            files[path] = file
+          }
+        } else {
+          files[path] = file
+        }
+
         cb()
       })
     },
@@ -170,12 +196,12 @@ function buildFiles(metalsmith, paths, livereload, options, previousFilesMap) {
 
       const nbOfFiles = Object.keys(files).length
       options.log(color.gray(`- Updating ${nbOfFiles} file${nbOfFiles > 1 ? "s" : ""}...`))
-      runAndUpdate(metalsmith, files, livereload, options, previousFilesMap)
+      runAndUpdate(metalsmith, files, livereload, onUpdateCallback, options, previousFilesMap)
     }
   )
 }
 
-function buildPattern(metalsmith, patterns, livereload, options, previousFilesMap) {
+function buildPattern(metalsmith, patterns, livereload, onUpdateCallback, options, previousFilesMap) {
   unyield(metalsmith.read())((err, files) => {
     if (err) {
       options.log(color.red(`${nok} ${err}`))
@@ -186,7 +212,7 @@ function buildPattern(metalsmith, patterns, livereload, options, previousFilesMa
     multimatch(Object.keys(files), patterns).forEach(path => filesToUpdate[path] = files[path])
     const nbOfFiles = Object.keys(filesToUpdate).length
     options.log(color.gray(`- Updating ${nbOfFiles} file${nbOfFiles > 1 ? "s" : ""}...`))
-    runAndUpdate(metalsmith, filesToUpdate, livereload, options, previousFilesMap)
+    runAndUpdate(metalsmith, filesToUpdate, livereload, onUpdateCallback, options, previousFilesMap)
   })
 }
 
@@ -212,6 +238,11 @@ export default function(options) {
     livereload = livereloadServer(options.livereload, options.log)
   }
 
+  let onUpdateCallback
+  if (options.onUpdateCallback && typeof options.onUpdateCallback === 'function') {
+    onUpdateCallback = options.onUpdateCallback.bind(this);
+  }
+
   let watched = false
   const plugin = function metalsmithWatch(files, metalsmith, cb) {
 
@@ -223,7 +254,7 @@ export default function(options) {
     watched = true
 
     // metalsmith-collections fix: keep filename as metadata
-    saveFilenameInFilesData(files)
+    saveFilenameInFilesData(metalsmith, files, options)
 
     const patterns = {}
     Object.keys(options.paths).map(pattern => {
@@ -288,7 +319,7 @@ export default function(options) {
             return relativePath(metalsmith.source(), filepath)
           })
           if (filesToUpdate.length) {
-            buildFiles(metalsmith, filesToUpdate, livereload, options, previousFilesMap)
+            buildFiles(metalsmith, filesToUpdate, livereload, onUpdateCallback, options, previousFilesMap)
           }
 
           const patternsToUpdatePattern = Object.keys(patterns)
@@ -297,7 +328,7 @@ export default function(options) {
             .map(pattern => patterns[pattern])
 
           if (patternsToUpdatePattern.length) {
-            buildPattern(metalsmith, patternsToUpdatePattern, livereload, options, previousFilesMap)
+            buildPattern(metalsmith, patternsToUpdatePattern, livereload, onUpdateCallback, options, previousFilesMap)
           }
           // console.log(pathsToUpdate, filesToUpdate, patternsToUpdatePattern)