[glib/wip/oholy/bind-mounts-stable] gunixmounts: Filter out mounts with device path that was repeated

[Ondrej Holy <oholy src gnome org>]

commit ed88b23fdf5e9fac55b16e8e63e0ea1cfd73653c
Author: Ondrej Holy <oholy redhat com>
Date:   Fri Apr 27 10:06:23 2018 +0200

    gunixmounts: Filter out mounts with device path that was repeated
    
    libmount-based implementation doesn't filter out mounts with device
    path that was repeated as it is done with mntent-based implementation.
    It causes problems to our volume monitors which are not able to handle
    multiple mounts for one device path properly without additional API.
    Let's filter out the same mounts as are filtered out with mntent-based
    implementation.
    
    This is intended only for stable branches to prevent current issues.
    
    https://gitlab.gnome.org/GNOME/glib/issues/1271

 gio/gunixmounts.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
---
diff --git a/gio/gunixmounts.c b/gio/gunixmounts.c
index 355329c19..8cbd70f5f 100644
--- a/gio/gunixmounts.c
+++ b/gio/gunixmounts.c
@@ -461,6 +461,18 @@ create_unix_mount_point (const char *device_path,
  */
 #define PROC_MOUNTINFO_PATH "/proc/self/mountinfo"
 
+static int
+uniq_fs_source_cmp (struct libmnt_table *table G_GNUC_UNUSED,
+                    struct libmnt_fs *a,
+                    struct libmnt_fs *b)
+{
+  if (mnt_fs_is_pseudofs (a) || mnt_fs_is_netfs (a) ||
+      mnt_fs_is_pseudofs (b) || mnt_fs_is_netfs (b))
+    return 1;
+
+  return !mnt_fs_streq_srcpath (a, mnt_fs_get_srcpath (b));
+}
+
 static GList *
 _g_get_unix_mounts (void)
 {
@@ -482,6 +494,11 @@ _g_get_unix_mounts (void)
       unsigned long mount_flags = 0;
       gboolean is_read_only = FALSE;
 
+      /* Use only the first mount for device, see comment from _g_get_unix_mounts
+       * in #else branch.
+       */
+      mnt_table_uniq_fs (table, MNT_UNIQ_FORWARD, uniq_fs_source_cmp);
+
       device_path = mnt_fs_get_source (fs);
       if (g_strcmp0 (device_path, "/dev/root") == 0)
         device_path = _resolve_dev_root ();