Merge pull request #3998 from drwtsn32x/fix-attribute-masking

Disable file attribute masking on Windows 10

Duplicati/Library/Main/ProcessController.cs

@@ -234,6 +234,31 @@ namespace Duplicati.Library.Main
             }
         }
 
+        /// <summary>
+        /// Expose all filesystem attributes
+        /// </summary>
+        private static void ExposeAllFilesystemAttributes()
+        {
+            // Starting with Windows 10 1803, the operating system may mask the process's view of some
+            // file attributes such as reparse, offline, and sparse.
+            //
+            // This function will turn off such masking.
+            //
+            // See https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/ntifs/nf-ntifs-rtlqueryprocessplaceholdercompatibilitymode
+
+            if (Platform.IsClientWindows)
+            {
+                try
+                {
+                    Win32.RtlSetProcessPlaceholderCompatibilityMode(Win32.PHCM_VALUES.PHCM_EXPOSE_PLACEHOLDERS);
+                }
+                catch
+                {
+                    // Ignore exceptions - not applicable on this version of Windows
+                }
+            }
+        }
+
         /// <summary>
         /// Starts the process controller
         /// </summary>
@@ -245,6 +270,8 @@ namespace Duplicati.Library.Main
 
             if (options.UseBackgroundIOPriority)
                 ActivateBackgroundIOPriority();
+
+            ExposeAllFilesystemAttributes();
         }
 
         /// <summary>

Duplicati/Library/Utility/Win32.cs

@@ -170,6 +170,19 @@ namespace Duplicati.Library.Utility
             MaxProcessInfoClass
         }
 
+        /// <summary>
+        /// Placeholder Compatibility Mode values
+        /// </summary>
+        public enum PHCM_VALUES : sbyte
+        {
+            PHCM_APPLICATION_DEFAULT = 0,
+            PHCM_DISGUISE_PLACEHOLDER = 1,
+            PHCM_EXPOSE_PLACEHOLDERS = 2,
+            PHCM_MAX = 2,
+            PHCM_ERROR_INVALID_PARAMETER = -1,
+            PHCM_ERROR_NO_TEB = -2,
+        }
+
         #endregion
 
         #region Function calls
@@ -227,6 +240,15 @@ namespace Duplicati.Library.Utility
         /// <param name="handle">A handle to the process. The handle must have the PROCESS_SET_INFORMATION access right.</param>
         [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
         public static extern PROCESS_PRIORITY_CLASS GetPriorityClass(IntPtr handle);
+
+        /// <summary>
+        /// Sets the current placeholder compatibility mode for the process.
+        /// </summary>
+        /// <returns>The previous <see cref="PHCM_VALUES"/> value.</returns>
+        /// <param name="pcm">New value to set.</param>
+        [DllImport("ntdll.dll")]
+        public static extern PHCM_VALUES RtlSetProcessPlaceholderCompatibilityMode(PHCM_VALUES pcm);
+
         #endregion
     }
 }