diff --git a/third_party/linux/external/0002-watch_queue-Introduce-a-non-repeating-system-unique-.patch b/third_party/linux/external/0002-watch_queue-Introduce-a-non-repeating-system-unique-.patch
new file mode 100644
index 0000000..c3d4367
--- /dev/null
+++ b/third_party/linux/external/0002-watch_queue-Introduce-a-non-repeating-system-unique-.patch
@@ -0,0 +1,98 @@
+From 695a880f7d1bf86090dae3c32e3dc67c30917267 Mon Sep 17 00:00:00 2001
+From: David Howells <dhowells@redhat.com>
+Date: Fri, 5 Jul 2019 11:10:10 +0100
+Subject: [PATCH 2/4] watch_queue: Introduce a non-repeating system-unique
+ superblock ID
+
+Introduce an (effectively) non-repeating system-unique superblock ID that
+can be used to determine that two object are in the same superblock without
+risking reuse of the ID in the meantime (as is possible with device IDs).
+
+The ID is time-based to make it harder to use it as a covert communications
+channel.
+
+In future patches, this ID will be used to tag superblock notification
+messages.  It will also be made queryable.
+
+Signed-off-by: David Howells <dhowells@redhat.com>
+---
+ fs/internal.h      |  1 +
+ fs/super.c         | 24 ++++++++++++++++++++++++
+ include/linux/fs.h |  3 +++
+ 3 files changed, 28 insertions(+)
+
+diff --git a/fs/internal.h b/fs/internal.h
+index f3f280b952a3..a0d90f23593c 100644
+--- a/fs/internal.h
++++ b/fs/internal.h
+@@ -109,6 +109,7 @@ extern int reconfigure_super(struct fs_context *);
+ extern bool trylock_super(struct super_block *sb);
+ extern struct super_block *user_get_super(dev_t);
+ extern bool mount_capable(struct fs_context *);
++extern void vfs_generate_unique_id(u64 *);
+ 
+ /*
+  * open.c
+diff --git a/fs/super.c b/fs/super.c
+index cd352530eca9..ececa5695fd1 100644
+--- a/fs/super.c
++++ b/fs/super.c
+@@ -44,6 +44,8 @@ static int thaw_super_locked(struct super_block *sb);
+ 
+ static LIST_HEAD(super_blocks);
+ static DEFINE_SPINLOCK(sb_lock);
++static u64 vfs_last_identifier;
++static u64 vfs_identifier_offset;
+ 
+ static char *sb_writers_name[SB_FREEZE_LEVELS] = {
+ 	"sb_writers",
+@@ -273,6 +275,7 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
+ 		goto fail;
+ 	if (list_lru_init_memcg(&s->s_inode_lru, &s->s_shrink))
+ 		goto fail;
++	vfs_generate_unique_id(&s->s_unique_id);
+ 	return s;
+ 
+ fail:
+@@ -1867,3 +1870,24 @@ int thaw_super(struct super_block *sb)
+ 	return thaw_super_locked(sb);
+ }
+ EXPORT_SYMBOL(thaw_super);
++
++/*
++ * Generate a unique identifier for a superblock or mount object.
++ */
++void vfs_generate_unique_id(u64 *_id)
++{
++	u64 id = ktime_to_ns(ktime_get());
++
++	spin_lock(&sb_lock);
++
++	id += vfs_identifier_offset;
++	if (id <= vfs_last_identifier) {
++		id = vfs_last_identifier + 1;
++		vfs_identifier_offset = vfs_last_identifier - id;
++	}
++
++	vfs_last_identifier = id;
++	spin_unlock(&sb_lock);
++
++	*_id = id;
++}
+diff --git a/include/linux/fs.h b/include/linux/fs.h
+index abedbffe2c9e..fb0db8474141 100644
+--- a/include/linux/fs.h
++++ b/include/linux/fs.h
+@@ -1549,6 +1549,9 @@ struct super_block {
+ 
+ 	spinlock_t		s_inode_wblist_lock;
+ 	struct list_head	s_inodes_wb;	/* writeback inodes */
++
++	/* Superblock event notifications */
++	u64			s_unique_id;
+ } __randomize_layout;
+ 
+ /* Helper functions so that in most cases filesystems will
+-- 
+2.20.1
+