From 57036a3de3d3a567da2618de64895ee0bc31297c Mon Sep 17 00:00:00 2001
From: Phillip Susi <psusi@ubuntu.com>
Date: Sun, 22 Jun 2014 19:23:05 -0400
Subject: [PATCH] Fix standby timers

If the drive was set to standby after >= 10 minutes of inactivity,
it would never standby because udisks would check every 10 minutes
to see if it was already in standby, and if not, update the SMART
stats, which would reset the standby timer.  This is especially
problematic since many drives enforce a 10 minute minimum standby
timer even if a lower value is specified.

This patch checks the kernel IO stats to see if any other IO has
been done on the drive since the last check, and if not, behaves
as if the drive is already sleeping.
---
 src/udiskslinuxdriveata.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/udiskslinuxdriveata.c b/src/udiskslinuxdriveata.c
index 9148dee..4184732 100644
--- a/src/udiskslinuxdriveata.c
+++ b/src/udiskslinuxdriveata.c
@@ -88,6 +88,8 @@ struct _UDisksLinuxDriveAta
   UDisksThreadedJob *selftest_job;
 
   gboolean     secure_erase_in_progress;
+  unsigned long driveread, drivewrite;
+  gboolean     standby_enabled;
 };
 
 struct _UDisksLinuxDriveAtaClass
@@ -463,6 +465,32 @@ static gboolean get_pm_state (UDisksLinuxDevice *device, GError **error, guchar
   return rc;
 }
 
+static gboolean update_io_stats (UDisksLinuxDriveAta *drive, UDisksLinuxDevice *device)
+{
+  const gchar *drivepath = g_udev_device_get_sysfs_path (device->udev_device);
+  gchar statpath[1024];
+  unsigned long driveread, drivewrite;
+  FILE *statf;
+  gboolean noio = FALSE;
+  snprintf (statpath, sizeof(statpath), "%s/stat", drivepath);
+  statf = fopen (statpath, "r");
+  if (statf == NULL)
+    {
+      udisks_warning ("Failed to open %s\n", statpath);
+    }
+  else
+    {
+      fscanf (statf, "%lu %*u %*u %*u %lu", &driveread, &drivewrite);
+      fclose (statf);
+      noio = driveread == drive->driveread && drivewrite == drive->drivewrite;
+      udisks_debug ("driveread=%lu, drivewrite=%lu, old_driveread=%lu, old_drivewrite=%lu\n",
+                    driveread, drivewrite, drive->driveread, drive->drivewrite);
+      drive->driveread = driveread;
+      drive->drivewrite = drivewrite;
+    }
+  return noio;
+}
+
 /**
  * udisks_linux_drive_ata_refresh_smart_sync:
  * @drive: The #UDisksLinuxDriveAta to refresh.
@@ -556,11 +584,14 @@ udisks_linux_drive_ata_refresh_smart_sync (UDisksLinuxDriveAta  *drive,
   else
     {
       guchar count;
+      gboolean noio = FALSE;
       if (!get_pm_state(device, error, &count))
         goto out;
       awake = count == 0xFF || count == 0x80;
+      if (drive->standby_enabled)
+        noio = update_io_stats (drive, device);
       /* don't wake up disk unless specically asked to */
-      if (nowakeup && !awake)
+      if (nowakeup && (!awake || noio))
         {
           g_set_error (error,
                        UDISKS_ERROR,
@@ -634,6 +665,8 @@ udisks_linux_drive_ata_refresh_smart_sync (UDisksLinuxDriveAta  *drive,
   update_smart (drive, device);
 
   ret = TRUE;
+  /* update stats again to account for the IO we just did to read the SMART info */
+  update_io_stats (drive, device);
 
  out:
   g_clear_object (&device);
@@ -1660,6 +1693,7 @@ apply_configuration_thread_func (gpointer user_data)
           udisks_notice ("Set standby timer to %s (value %d) on %s [%s]",
                          pretty, data->ata_pm_standby, device_file, udisks_drive_get_id (data->drive));
           g_free (pretty);
+          data->ata->standby_enabled = data->ata_pm_standby != 0;
         }
     }
 
-- 
1.9.1