From 40b36069323b64ddd8c5a944d8a74f79b624b438 Mon Sep 17 00:00:00 2001
From: Martin Pitt <martin.pitt@ubuntu.com>
Date: Tue, 5 Apr 2011 21:13:32 +0200
Subject: [PATCH 5/5] Force media validation on media change for in-kernel polling mode

When using the in-kernel poller the partition revalidation bug
https://bugzilla.kernel.org/show_bug.cgi?id=13029 still happens when removing
media from a drive (such as SD card readers). Work around this by applying the
same "open with O_NONBLOCK" trick that the continuous poller already does.

Also add a comment to poller_poll_device() why the weird double-open with
O_NONBLOCK is necessary.
---
 src/daemon.c |    9 +++++++++
 src/poller.c |   21 +++++++++++++++++++++
 src/poller.h |    3 +++
 3 files changed, 33 insertions(+), 0 deletions(-)

diff --git a/src/daemon.c b/src/daemon.c
index 0ba791d..f5bdc14 100644
--- a/src/daemon.c
+++ b/src/daemon.c
@@ -1069,6 +1069,15 @@ block_device_changed (Daemon *daemon,
           daemon_local_update_poller (daemon);
           daemon_local_update_spindown (daemon);
         }
+
+      /* work around the kernel not properly validating partitions after block
+       * device changes (like media removals for SD cards); see
+       * https://bugzilla.kernel.org/show_bug.cgi?id=13029 */
+      if (device->priv->supports_media_change_event && g_udev_device_get_property (d, "DISK_MEDIA_CHANGE"))
+        {
+          g_print ("**** DISK_MEDIA_CHANGE event on %s, re-checking for media\n", device->priv->device_file);
+          poller_check_media (device);
+        }
     }
   else
     {
diff --git a/src/poller.c b/src/poller.c
index a75bacc..8c7a7d8 100644
--- a/src/poller.c
+++ b/src/poller.c
@@ -136,6 +136,9 @@ poller_poll_device (const gchar *device_file)
     }
   else
     {
+      /* we need to use O_NONBLOCK here to cause partition devices to go
+       * away after media removal; that won't fail with ENOMEDIA.
+       * See https://bugzilla.kernel.org/show_bug.cgi?id=13029 */
       fd = open (device_file, O_RDONLY);
       fd2 = open (device_file, O_RDONLY | O_NONBLOCK);
       if (fd != -1)
@@ -258,6 +261,10 @@ poller_have_data (GIOChannel *channel,
       poller_do_lock_cdtray (tokens[1], atoi (tokens[0]));
       g_strfreev (tokens);
     }
+  else if (g_str_has_prefix (line, "check-media:"))
+    {
+      poller_poll_device (line + strlen ("check-media:"));
+    }
   else
     {
       g_printerr ("**** POLLER (%d): unknown command '%s'\n", getpid (), line);
@@ -462,3 +469,17 @@ poller_lock_cdtray (Device* device, gboolean lock)
 }
 
 /* ---------------------------------------------------------------------------------------------------- */
+
+void poller_check_media (Device* device)
+{
+  gchar *command;
+
+  command = g_strconcat ("check-media:", device->priv->device_file, "\n", NULL);
+#ifdef POLL_SHOW_DEBUG
+  g_print ("**** POLLER (%d): Sending media check command: '%s'\n", getpid (), command);
+#endif
+  if (write (poller_daemon_write_end_fd, command, strlen (command)) < 0)
+    g_error ("**** POLLER (%d): Failed to send media check command: %s", getpid (), g_strerror (errno));
+}
+
+/* ---------------------------------------------------------------------------------------------------- */
diff --git a/src/poller.h b/src/poller.h
index 67eb9fc..ae130ce 100644
--- a/src/poller.h
+++ b/src/poller.h
@@ -31,4 +31,7 @@ void poller_set_devices (GList *devices);
 /* CD tray handling; moved to poller as it could block for a longer time */
 void poller_lock_cdtray (Device* device, gboolean lock);
 
+/* One-time check for media or updated/removed partitions on a device */
+void poller_check_media (Device* device);
+
 #endif /* __POLLER_H */
-- 
1.7.4.1