core,shutdown: don't bother with unmounting any mounts below /sys, /proc, /dev when shutting down

After all, mounts below these directories are pretty much guaranteed to
be virtual, and it's hence unnecessary to unmount them during shutdown.
Moreover, in less-priviliged containers we might lack the rights to
unmount them, hence don't even try.

http://lists.freedesktop.org/archives/systemd-devel/2015-January/027113.html

1 files changed, 8 insertions, 2 deletions

diff --git a/src/core/umount.c b/src/core/umount.c
index e38851dc12..dd7df194de 100644
--- a/src/core/umount.c
+++ b/src/core/umount.c
@@ -104,10 +104,16 @@ static int mount_points_list_get(MountPoint **head) {
 
                 /* Ignore mount points we can't unmount because they
                  * are API or because we are keeping them open (like
-                 * /dev/console) */
+                 * /dev/console). Also, ignore all mounts below API
+                 * file systems, since they are likely virtual too,
+                 * and hence not worth spending time on. Also, in
+                 * unprivileged containers we might lack the rights to
+                 * unmount these things, hence don't bother. */
                 if (mount_point_is_api(p) ||
                     mount_point_ignore(p) ||
-                    path_equal(p, "/dev/console")) {
+                    path_startswith(p, "/dev") ||
+                    path_startswith(p, "/sys") ||
+                    path_startswith(p, "/proc")) {
                         free(p);
                         continue;
                 }