diff --git a/src/corelib/io/qabstractfileengine.cpp b/src/corelib/io/qabstractfileengine.cpp
index 9606ec68e9c..89727673d31 100644
--- a/src/corelib/io/qabstractfileengine.cpp
+++ b/src/corelib/io/qabstractfileengine.cpp
@@ -677,6 +677,17 @@ bool QAbstractFileEngine::setPermissions(uint perms)
     return false;
 }
 
+/*!
+    \since 5.9
+
+    Return an identifier that (hopefully) uniquely identifies this file in the
+    system. Returns an invalid QByteArray() if that cannot be calculated.
+*/
+QByteArray QAbstractFileEngine::id() const
+{
+    return QByteArray();
+}
+
 /*!
     Return  the file engine's current file name in the format
     specified by \a file.
diff --git a/src/corelib/io/qabstractfileengine_p.h b/src/corelib/io/qabstractfileengine_p.h
index 48b3dec3249..58fa776e49a 100644
--- a/src/corelib/io/qabstractfileengine_p.h
+++ b/src/corelib/io/qabstractfileengine_p.h
@@ -141,6 +141,7 @@ public:
     virtual QStringList entryList(QDir::Filters filters, const QStringList &filterNames) const;
     virtual FileFlags fileFlags(FileFlags type=FileInfoAll) const;
     virtual bool setPermissions(uint perms);
+    virtual QByteArray id() const;
     virtual QString fileName(FileName file=DefaultName) const;
     virtual uint ownerId(FileOwner) const;
     virtual QString owner(FileOwner) const;
diff --git a/src/corelib/io/qfile.cpp b/src/corelib/io/qfile.cpp
index a8403071452..f7e711a7cf7 100644
--- a/src/corelib/io/qfile.cpp
+++ b/src/corelib/io/qfile.cpp
@@ -570,7 +570,9 @@ QFile::rename(const QString &newName)
     // Note: this does not take file engines into account.
     QByteArray targetId = QFileSystemEngine::id(QFileSystemEntry(newName));
     if (!targetId.isNull()) {
-        QByteArray fileId = QFileSystemEngine::id(QFileSystemEntry(d->fileName));
+        QByteArray fileId = d->fileEngine ?
+                    d->fileEngine->id() :
+                    QFileSystemEngine::id(QFileSystemEntry(d->fileName));
         if (fileId != targetId || d->fileName.compare(newName, Qt::CaseInsensitive)) {
             // ### Race condition. If a file is moved in after this, it /will/ be
             // overwritten. On Unix, the proper solution is to use hardlinks:
diff --git a/src/corelib/io/qfilesystemengine_p.h b/src/corelib/io/qfilesystemengine_p.h
index 196ed8df698..e3e52f6eaad 100644
--- a/src/corelib/io/qfilesystemengine_p.h
+++ b/src/corelib/io/qfilesystemengine_p.h
@@ -92,6 +92,7 @@ public:
                              QFileSystemMetaData::MetaDataFlags what);
 #if defined(Q_OS_UNIX)
     static bool fillMetaData(int fd, QFileSystemMetaData &data); // what = PosixStatFlags
+    static QByteArray id(int fd);
     static bool setPermissions(int fd, QFile::Permissions permissions, QSystemError &error,
                                QFileSystemMetaData *data = nullptr);
 #endif
@@ -104,6 +105,7 @@ public:
                              QFileSystemMetaData::MetaDataFlags what);
     static bool fillPermissions(const QFileSystemEntry &entry, QFileSystemMetaData &data,
                                 QFileSystemMetaData::MetaDataFlags what);
+    static QByteArray id(HANDLE fHandle);
     static QString owner(const QFileSystemEntry &entry, QAbstractFileEngine::FileOwner own);
     static QString nativeAbsoluteFilePath(const QString &path);
 #endif
diff --git a/src/corelib/io/qfilesystemengine_unix.cpp b/src/corelib/io/qfilesystemengine_unix.cpp
index c3906c3207e..6640e2b7e72 100644
--- a/src/corelib/io/qfilesystemengine_unix.cpp
+++ b/src/corelib/io/qfilesystemengine_unix.cpp
@@ -348,6 +348,20 @@ QByteArray QFileSystemEngine::id(const QFileSystemEntry &entry)
     return result;
 }
 
+//static
+QByteArray QFileSystemEngine::id(int id)
+{
+    QT_STATBUF statResult;
+    if (QT_FSTAT(id, &statResult)) {
+        qErrnoWarning("fstat() failed for fd %d", id);
+        return QByteArray();
+    }
+    QByteArray result = QByteArray::number(quint64(statResult.st_dev), 16);
+    result += ':';
+    result += QByteArray::number(quint64(statResult.st_ino));
+    return result;
+}
+
 //static
 QString QFileSystemEngine::resolveUserName(uint userId)
 {
diff --git a/src/corelib/io/qfilesystemengine_win.cpp b/src/corelib/io/qfilesystemengine_win.cpp
index 5ed2671ab4e..1cb4c756999 100644
--- a/src/corelib/io/qfilesystemengine_win.cpp
+++ b/src/corelib/io/qfilesystemengine_win.cpp
@@ -621,13 +621,19 @@ QByteArray QFileSystemEngine::id(const QFileSystemEntry &entry)
                     FILE_SHARE_READ, OPEN_EXISTING, NULL);
 #endif // Q_OS_WINRT
     if (handle != INVALID_HANDLE_VALUE) {
-        result = QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows8 ?
-                 fileIdWin8(handle) : fileId(handle);
+        result = id(handle);
         CloseHandle(handle);
     }
     return result;
 }
 
+//static
+QByteArray QFileSystemEngine::id(HANDLE fHandle)
+{
+    return QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows8 ?
+                fileIdWin8(HANDLE(fHandle)) : fileId(HANDLE(fHandle));
+}
+
 //static
 QString QFileSystemEngine::owner(const QFileSystemEntry &entry, QAbstractFileEngine::FileOwner own)
 {
diff --git a/src/corelib/io/qfsfileengine_p.h b/src/corelib/io/qfsfileengine_p.h
index 593ecc26871..ab9ad3aa6b7 100644
--- a/src/corelib/io/qfsfileengine_p.h
+++ b/src/corelib/io/qfsfileengine_p.h
@@ -93,6 +93,7 @@ public:
     QStringList entryList(QDir::Filters filters, const QStringList &filterNames) const Q_DECL_OVERRIDE;
     FileFlags fileFlags(FileFlags type) const Q_DECL_OVERRIDE;
     bool setPermissions(uint perms) Q_DECL_OVERRIDE;
+    QByteArray id() const override;
     QString fileName(FileName file) const Q_DECL_OVERRIDE;
     uint ownerId(FileOwner) const Q_DECL_OVERRIDE;
     QString owner(FileOwner) const Q_DECL_OVERRIDE;
diff --git a/src/corelib/io/qfsfileengine_unix.cpp b/src/corelib/io/qfsfileengine_unix.cpp
index 3f4f593d811..c613368a91f 100644
--- a/src/corelib/io/qfsfileengine_unix.cpp
+++ b/src/corelib/io/qfsfileengine_unix.cpp
@@ -596,6 +596,14 @@ QAbstractFileEngine::FileFlags QFSFileEngine::fileFlags(FileFlags type) const
     return ret;
 }
 
+QByteArray QFSFileEngine::id() const
+{
+    Q_D(const QFSFileEngine);
+    if (d->fd != -1)
+        return QFileSystemEngine::id(d->fd);
+    return QFileSystemEngine::id(d->fileEntry);
+}
+
 QString QFSFileEngine::fileName(FileName file) const
 {
     Q_D(const QFSFileEngine);
diff --git a/src/corelib/io/qfsfileengine_win.cpp b/src/corelib/io/qfsfileengine_win.cpp
index fb3cdd39818..7a010df671b 100644
--- a/src/corelib/io/qfsfileengine_win.cpp
+++ b/src/corelib/io/qfsfileengine_win.cpp
@@ -718,6 +718,24 @@ QAbstractFileEngine::FileFlags QFSFileEngine::fileFlags(QAbstractFileEngine::Fil
     return ret;
 }
 
+QByteArray QFSFileEngine::id() const
+{
+    Q_D(const QFSFileEngine);
+    HANDLE h = d->fileHandle;
+    if (h == INVALID_HANDLE_VALUE) {
+        int localFd = d->fd;
+        if (d->fh && d->fileEntry.isEmpty())
+            localFd = QT_FILENO(d->fh);
+        if (localFd != -1)
+            h = HANDLE(_get_osfhandle(localFd));
+    }
+    if (h != INVALID_HANDLE_VALUE)
+        return QFileSystemEngine::id(h);
+
+    // file is not open, try by path
+    return QFileSystemEngine::id(d->fileEntry);
+}
+
 QString QFSFileEngine::fileName(FileName file) const
 {
     Q_D(const QFSFileEngine);