diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 36d42da7466a..b869428033ef 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -477,3 +477,4 @@
 # 545 reserved for clone3
 547	common	openat2				sys_openat2
 548	common	pidfd_getfd			sys_pidfd_getfd
+549	common	watch_mount			sys_watch_mount
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 4d1cf74a2caa..9c389da9efcc 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -451,3 +451,4 @@
 435	common	clone3				sys_clone3
 437	common	openat2				sys_openat2
 438	common	pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount			sys_watch_mount
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 1dd22da1c3a9..75f04a1023be 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -38,7 +38,7 @@
 #define __ARM_NR_compat_set_tls		(__ARM_NR_COMPAT_BASE + 5)
 #define __ARM_NR_COMPAT_END		(__ARM_NR_COMPAT_BASE + 0x800)
 
-#define __NR_compat_syscalls		439
+#define __NR_compat_syscalls		440
 #endif
 
 #define __ARCH_WANT_SYS_CLONE
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index 042911e670b8..6817f865cc71 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -358,3 +358,4 @@
 # 435 reserved for clone3
 437	common	openat2				sys_openat2
 438	common	pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount			sys_watch_mount
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index f4f49fcb76d0..fbf85da75ecb 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -437,3 +437,4 @@
 435	common	clone3				__sys_clone3
 437	common	openat2				sys_openat2
 438	common	pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount			sys_watch_mount
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 4c67b11f9c9e..b05b192da1e2 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -443,3 +443,4 @@
 435	common	clone3				sys_clone3
 437	common	openat2				sys_openat2
 438	common	pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount			sys_watch_mount
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index 1f9e8ad636cc..0f85d2a033f9 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -376,3 +376,4 @@
 435	n32	clone3				__sys_clone3
 437	n32	openat2				sys_openat2
 438	n32	pidfd_getfd			sys_pidfd_getfd
+439	n32	watch_mount			sys_watch_mount
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index c0b9d802dbf6..905cf9ac0792 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -352,3 +352,4 @@
 435	n64	clone3				__sys_clone3
 437	n64	openat2				sys_openat2
 438	n64	pidfd_getfd			sys_pidfd_getfd
+439	n64	watch_mount			sys_watch_mount
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index ac586774c980..834b26b08d74 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -425,3 +425,4 @@
 435	o32	clone3				__sys_clone3
 437	o32	openat2				sys_openat2
 438	o32	pidfd_getfd			sys_pidfd_getfd
+439	o32	watch_mount			sys_watch_mount
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 52a15f5cd130..badd3449db43 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -435,3 +435,4 @@
 435	common	clone3				sys_clone3_wrapper
 437	common	openat2				sys_openat2
 438	common	pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount			sys_watch_mount
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 35b61bfc1b1a..b404361bc929 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -519,3 +519,4 @@
 435	nospu	clone3				ppc_clone3
 437	common	openat2				sys_openat2
 438	common	pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount			sys_watch_mount
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index bd7bd3581a0f..33071de24511 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -440,3 +440,4 @@
 435  common	clone3			sys_clone3			sys_clone3
 437  common	openat2			sys_openat2			sys_openat2
 438  common	pidfd_getfd		sys_pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount		sys_watch_mount			sys_watch_mount
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index c7a30fcd135f..682c125122f4 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -440,3 +440,4 @@
 # 435 reserved for clone3
 437	common	openat2				sys_openat2
 438	common	pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount			sys_watch_mount
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index f13615ecdecc..febf3cd675e3 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -483,3 +483,4 @@
 # 435 reserved for clone3
 437	common	openat2			sys_openat2
 438	common	pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount			sys_watch_mount
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index c17cb77eb150..085bcc5afdf1 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -442,3 +442,4 @@
 435	i386	clone3			sys_clone3			__ia32_sys_clone3
 437	i386	openat2			sys_openat2			__ia32_sys_openat2
 438	i386	pidfd_getfd		sys_pidfd_getfd			__ia32_sys_pidfd_getfd
+439	i386	watch_mount		sys_watch_mount			__ia32_sys_watch_mount
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 44d510bc9b78..9cfb6b2eb319 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -359,6 +359,7 @@
 435	common	clone3			__x64_sys_clone3/ptregs
 437	common	openat2			__x64_sys_openat2
 438	common	pidfd_getfd		__x64_sys_pidfd_getfd
+439	common	watch_mount		__x64_sys_watch_mount
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 85a9ab1bc04d..1a066a43a58b 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -408,3 +408,4 @@
 435	common	clone3				sys_clone3
 437	common	openat2				sys_openat2
 438	common	pidfd_getfd			sys_pidfd_getfd
+439	common	watch_mount			sys_watch_mount
diff --git a/fs/Kconfig b/fs/Kconfig
index 708ba336e689..d7039137d538 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -117,6 +117,15 @@ source "fs/verity/Kconfig"
 
 source "fs/notify/Kconfig"
 
+config MOUNT_NOTIFICATIONS
+	bool "Mount topology change notifications"
+	select WATCH_QUEUE
+	help
+	  This option provides support for getting change notifications on the
+	  mount tree topology.  This makes use of the /dev/watch_queue misc
+	  device to handle the notification buffer and provides the
+	  mount_notify() system call to enable/disable watchpoints.
+
 source "fs/quota/Kconfig"
 
 source "fs/autofs/Kconfig"
diff --git a/fs/Makefile b/fs/Makefile
index 505e51166973..4477757780d0 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -22,6 +22,7 @@ obj-y +=	no-block.o
 endif
 
 obj-$(CONFIG_PROC_FS) += proc_namespace.o
+obj-$(CONFIG_MOUNT_NOTIFICATIONS) += mount_notify.o
 
 obj-y				+= notify/
 obj-$(CONFIG_EPOLL)		+= eventpoll.o
diff --git a/fs/mount.h b/fs/mount.h
index 711a4093e475..381f842f3a27 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -4,6 +4,7 @@
 #include <linux/poll.h>
 #include <linux/ns_common.h>
 #include <linux/fs_pin.h>
+#include <linux/watch_queue.h>
 
 struct mnt_namespace {
 	atomic_t		count;
@@ -72,6 +73,12 @@ struct mount {
 	int mnt_expiry_mark;		/* true if marked for expiry */
 	struct hlist_head mnt_pins;
 	struct hlist_head mnt_stuck_children;
+#ifdef CONFIG_MOUNT_NOTIFICATIONS
+	atomic_t mnt_topology_changes;	/* Number of topology changes applied */
+	atomic_t mnt_attr_changes;	/* Number of attribute changes applied */
+	atomic_t mnt_subtree_notifications;	/* Number of notifications in subtree */
+	struct watch_list *mnt_watchers; /* Watches on dentries within this mount */
+#endif
 } __randomize_layout;
 
 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
@@ -153,3 +160,31 @@ static inline bool is_anon_ns(struct mnt_namespace *ns)
 {
 	return ns->seq == 0;
 }
+
+extern void post_mount_notification(struct mount *changed,
+				    struct mount_notification *notify);
+
+static inline void notify_mount(struct mount *changed,
+				struct mount *aux,
+				enum mount_notification_subtype subtype,
+				u32 info_flags)
+{
+#ifdef CONFIG_MOUNT_NOTIFICATIONS
+	if (aux)
+		atomic_inc(&changed->mnt_topology_changes);
+	else
+		atomic_inc(&changed->mnt_attr_changes);
+
+	{
+		struct mount_notification n = {
+			.watch.type	= WATCH_TYPE_MOUNT_NOTIFY,
+			.watch.subtype	= subtype,
+			.watch.info	= info_flags | watch_sizeof(n),
+			.triggered_on	= changed->mnt_id,
+			.changed_mount	= aux ? aux->mnt_id : 0,
+		};
+
+		post_mount_notification(changed, &n);
+	}
+#endif
+}
diff --git a/fs/mount_notify.c b/fs/mount_notify.c
new file mode 100644
index 000000000000..d946765afcc4
--- /dev/null
+++ b/fs/mount_notify.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Provide mount topology/attribute change notifications.
+ *
+ * Copyright (C) 2019 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/syscalls.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include "mount.h"
+
+/*
+ * Post mount notifications to all watches going rootwards along the tree.
+ *
+ * Must be called with the mount_lock held.
+ */
+void post_mount_notification(struct mount *changed,
+			     struct mount_notification *notify)
+{
+	const struct cred *cred = current_cred();
+	struct path cursor;
+	struct mount *mnt;
+	unsigned seq;
+
+	seq = 0;
+	rcu_read_lock();
+restart:
+	cursor.mnt = &changed->mnt;
+	cursor.dentry = changed->mnt.mnt_root;
+	mnt = real_mount(cursor.mnt);
+	notify->watch.info &= ~NOTIFY_MOUNT_IN_SUBTREE;
+
+	read_seqbegin_or_lock(&rename_lock, &seq);
+	for (;;) {
+		if (mnt->mnt_watchers &&
+		    !hlist_empty(&mnt->mnt_watchers->watchers)) {
+			if (cursor.dentry->d_flags & DCACHE_MOUNT_WATCH)
+				post_watch_notification(mnt->mnt_watchers,
+							&notify->watch, cred,
+							(unsigned long)cursor.dentry);
+		} else {
+			cursor.dentry = mnt->mnt.mnt_root;
+		}
+		notify->watch.info |= NOTIFY_MOUNT_IN_SUBTREE;
+
+		if (cursor.dentry == cursor.mnt->mnt_root ||
+		    IS_ROOT(cursor.dentry)) {
+			struct mount *parent = READ_ONCE(mnt->mnt_parent);
+
+			/* Escaped? */
+			if (cursor.dentry != cursor.mnt->mnt_root)
+				break;
+
+			/* Global root? */
+			if (mnt == parent)
+				break;
+
+			cursor.dentry = READ_ONCE(mnt->mnt_mountpoint);
+			mnt = parent;
+			cursor.mnt = &mnt->mnt;
+			atomic_inc(&mnt->mnt_subtree_notifications);
+		} else {
+			cursor.dentry = cursor.dentry->d_parent;
+		}
+	}
+
+	if (need_seqretry(&rename_lock, seq)) {
+		seq = 1;
+		goto restart;
+	}
+
+	done_seqretry(&rename_lock, seq);
+	rcu_read_unlock();
+}
+
+static void release_mount_watch(struct watch *watch)
+{
+	struct dentry *dentry = (struct dentry *)(unsigned long)watch->id;
+
+	dput(dentry);
+}
+
+/**
+ * sys_watch_mount - Watch for mount topology/attribute changes
+ * @dfd: Base directory to pathwalk from or fd referring to mount.
+ * @filename: Path to mount to place the watch upon
+ * @at_flags: Pathwalk control flags
+ * @watch_fd: The watch queue to send notifications to.
+ * @watch_id: The watch ID to be placed in the notification (-1 to remove watch)
+ */
+SYSCALL_DEFINE5(watch_mount,
+		int, dfd,
+		const char __user *, filename,
+		unsigned int, at_flags,
+		int, watch_fd,
+		int, watch_id)
+{
+	struct watch_queue *wqueue;
+	struct watch_list *wlist = NULL;
+	struct watch *watch = NULL;
+	struct mount *m;
+	struct path path;
+	unsigned int lookup_flags =
+		LOOKUP_DIRECTORY | LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
+	int ret;
+
+	if (watch_id < -1 || watch_id > 0xff)
+		return -EINVAL;
+	if ((at_flags & ~(AT_NO_AUTOMOUNT | AT_EMPTY_PATH)) != 0)
+		return -EINVAL;
+	if (at_flags & AT_NO_AUTOMOUNT)
+		lookup_flags &= ~LOOKUP_AUTOMOUNT;
+	if (at_flags & AT_EMPTY_PATH)
+		lookup_flags |= LOOKUP_EMPTY;
+
+	ret = user_path_at(dfd, filename, lookup_flags, &path);
+	if (ret)
+		return ret;
+
+	ret = inode_permission(path.dentry->d_inode, MAY_EXEC);
+	if (ret)
+		goto err_path;
+
+	wqueue = get_watch_queue(watch_fd);
+	if (IS_ERR(wqueue))
+		goto err_path;
+
+	m = real_mount(path.mnt);
+
+	if (watch_id >= 0) {
+		ret = -ENOMEM;
+		if (!READ_ONCE(m->mnt_watchers)) {
+			wlist = kzalloc(sizeof(*wlist), GFP_KERNEL);
+			if (!wlist)
+				goto err_wqueue;
+			init_watch_list(wlist, release_mount_watch);
+		}
+
+		watch = kzalloc(sizeof(*watch), GFP_KERNEL);
+		if (!watch)
+			goto err_wlist;
+
+		init_watch(watch, wqueue);
+		watch->id		= (unsigned long)path.dentry;
+		watch->info_id		= (u32)watch_id << 24;
+
+		ret = security_watch_mount(watch, &path);
+		if (ret < 0)
+			goto err_watch;
+
+		down_write(&m->mnt.mnt_sb->s_umount);
+		if (!m->mnt_watchers) {
+			m->mnt_watchers = wlist;
+			wlist = NULL;
+		}
+
+		ret = add_watch_to_object(watch, m->mnt_watchers);
+		if (ret == 0) {
+			spin_lock(&path.dentry->d_lock);
+			path.dentry->d_flags |= DCACHE_MOUNT_WATCH;
+			spin_unlock(&path.dentry->d_lock);
+			dget(path.dentry);
+			watch = NULL;
+		}
+		up_write(&m->mnt.mnt_sb->s_umount);
+	} else {
+		down_write(&m->mnt.mnt_sb->s_umount);
+		ret = remove_watch_from_object(m->mnt_watchers, wqueue,
+					       (unsigned long)path.dentry,
+					       false);
+		up_write(&m->mnt.mnt_sb->s_umount);
+	}
+
+err_watch:
+	kfree(watch);
+err_wlist:
+	kfree(wlist);
+err_wqueue:
+	put_watch_queue(wqueue);
+err_path:
+	path_put(&path);
+	return ret;
+}
diff --git a/fs/namespace.c b/fs/namespace.c
index 85b5f7bea82e..54d237251941 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -498,6 +498,9 @@ static int mnt_make_readonly(struct mount *mnt)
 	smp_wmb();
 	mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD;
 	unlock_mount_hash();
+	if (ret == 0)
+		notify_mount(mnt, NULL, NOTIFY_MOUNT_READONLY,
+			     NOTIFY_MOUNT_IS_NOW_RO);
 	return ret;
 }
 
@@ -506,6 +509,7 @@ static int __mnt_unmake_readonly(struct mount *mnt)
 	lock_mount_hash();
 	mnt->mnt.mnt_flags &= ~MNT_READONLY;
 	unlock_mount_hash();
+	notify_mount(mnt, NULL, NOTIFY_MOUNT_READONLY, 0);
 	return 0;
 }
 
@@ -819,6 +823,7 @@ static struct mountpoint *unhash_mnt(struct mount *mnt)
  */
 static void umount_mnt(struct mount *mnt)
 {
+	notify_mount(mnt->mnt_parent, mnt, NOTIFY_MOUNT_UNMOUNT, 0);
 	put_mountpoint(unhash_mnt(mnt));
 }
 
@@ -1159,6 +1164,11 @@ static void mntput_no_expire(struct mount *mnt)
 	mnt->mnt.mnt_flags |= MNT_DOOMED;
 	rcu_read_unlock();
 
+#ifdef CONFIG_MOUNT_NOTIFICATIONS
+	if (mnt->mnt_watchers)
+		remove_watch_list(mnt->mnt_watchers, mnt->mnt_id);
+#endif
+
 	list_del(&mnt->mnt_instance);
 
 	if (unlikely(!list_empty(&mnt->mnt_mounts))) {
@@ -1453,6 +1463,7 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
 		p = list_first_entry(&tmp_list, struct mount, mnt_list);
 		list_del_init(&p->mnt_expire);
 		list_del_init(&p->mnt_list);
+
 		ns = p->mnt_ns;
 		if (ns) {
 			ns->mounts--;
@@ -2079,7 +2090,10 @@ static int attach_recursive_mnt(struct mount *source_mnt,
 	}
 	if (moving) {
 		unhash_mnt(source_mnt);
+		notify_mount(source_mnt->mnt_parent, source_mnt,
+			     NOTIFY_MOUNT_MOVE_FROM, 0);
 		attach_mnt(source_mnt, dest_mnt, dest_mp);
+		notify_mount(dest_mnt, source_mnt, NOTIFY_MOUNT_MOVE_TO, 0);
 		touch_mnt_namespace(source_mnt->mnt_ns);
 	} else {
 		if (source_mnt->mnt_ns) {
@@ -2088,6 +2102,11 @@ static int attach_recursive_mnt(struct mount *source_mnt,
 		}
 		mnt_set_mountpoint(dest_mnt, dest_mp, source_mnt);
 		commit_tree(source_mnt);
+		notify_mount(dest_mnt, source_mnt, NOTIFY_MOUNT_NEW_MOUNT,
+			     (source_mnt->mnt.mnt_sb->s_flags & SB_RDONLY ?
+			      NOTIFY_MOUNT_IS_NOW_RO : 0) |
+			     (source_mnt->mnt.mnt_sb->s_flags & SB_SUBMOUNT ?
+			      NOTIFY_MOUNT_IS_SUBMOUNT : 0));
 	}
 
 	hlist_for_each_entry_safe(child, n, &tree_list, mnt_hash) {
@@ -2464,6 +2483,8 @@ static void set_mount_attributes(struct mount *mnt, unsigned int mnt_flags)
 	mnt->mnt.mnt_flags = mnt_flags;
 	touch_mnt_namespace(mnt->mnt_ns);
 	unlock_mount_hash();
+	notify_mount(mnt, NULL, NOTIFY_MOUNT_SETATTR,
+		     (mnt_flags & SB_RDONLY ? NOTIFY_MOUNT_IS_NOW_RO : 0));
 }
 
 static void mnt_warn_timestamp_expiry(struct path *mountpoint, struct vfsmount *mnt)
@@ -2899,6 +2920,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
 			propagate_mount_busy(mnt, 1))
 			continue;
 		list_move(&mnt->mnt_expire, &graveyard);
+		notify_mount(mnt, NULL, NOTIFY_MOUNT_EXPIRY, 0);
 	}
 	while (!list_empty(&graveyard)) {
 		mnt = list_first_entry(&graveyard, struct mount, mnt_expire);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index c1488cc84fd9..7b194d778155 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -217,6 +217,7 @@ struct dentry_operations {
 #define DCACHE_PAR_LOOKUP		0x10000000 /* being looked up (with parent locked shared) */
 #define DCACHE_DENTRY_CURSOR		0x20000000
 #define DCACHE_NORCU			0x40000000 /* No RCU delay for freeing */
+#define DCACHE_MOUNT_WATCH		0x80000000 /* There's a mount watch here */
 
 extern seqlock_t rename_lock;
 
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 1815065d52f3..1fd43af3b22d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -1003,6 +1003,8 @@ asmlinkage long sys_pidfd_send_signal(int pidfd, int sig,
 				       siginfo_t __user *info,
 				       unsigned int flags);
 asmlinkage long sys_pidfd_getfd(int pidfd, int fd, unsigned int flags);
+asmlinkage long sys_watch_mount(int dfd, const char __user *path,
+				unsigned int at_flags, int watch_fd, int watch_id);
 
 /*
  * Architecture-specific system calls
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 3a3201e4618e..6b5748287883 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -855,9 +855,11 @@ __SYSCALL(__NR_clone3, sys_clone3)
 __SYSCALL(__NR_openat2, sys_openat2)
 #define __NR_pidfd_getfd 438
 __SYSCALL(__NR_pidfd_getfd, sys_pidfd_getfd)
+#define __NR_watch_mount 439
+__SYSCALL(__NR_watch_mount, sys_watch_mount)
 
 #undef __NR_syscalls
-#define __NR_syscalls 439
+#define __NR_syscalls 440
 
 /*
  * 32 bit systems traditionally used different
diff --git a/include/uapi/linux/watch_queue.h b/include/uapi/linux/watch_queue.h
index c3d8320b5d3a..b0f35cf51394 100644
--- a/include/uapi/linux/watch_queue.h
+++ b/include/uapi/linux/watch_queue.h
@@ -14,7 +14,8 @@
 enum watch_notification_type {
 	WATCH_TYPE_META		= 0,	/* Special record */
 	WATCH_TYPE_KEY_NOTIFY	= 1,	/* Key change event notification */
-	WATCH_TYPE__NR		= 2
+	WATCH_TYPE_MOUNT_NOTIFY	= 2,	/* Mount topology change notification */
+	WATCH_TYPE___NR		= 3
 };
 
 enum watch_meta_notification_subtype {
@@ -101,4 +102,33 @@ struct key_notification {
 	__u32	aux;		/* Per-type auxiliary data */
 };
 
+/*
+ * Type of mount topology change notification.
+ */
+enum mount_notification_subtype {
+	NOTIFY_MOUNT_NEW_MOUNT	= 0, /* New mount added */
+	NOTIFY_MOUNT_UNMOUNT	= 1, /* Mount removed manually */
+	NOTIFY_MOUNT_EXPIRY	= 2, /* Automount expired */
+	NOTIFY_MOUNT_READONLY	= 3, /* Mount R/O state changed */
+	NOTIFY_MOUNT_SETATTR	= 4, /* Mount attributes changed */
+	NOTIFY_MOUNT_MOVE_FROM	= 5, /* Mount moved from here */
+	NOTIFY_MOUNT_MOVE_TO	= 6, /* Mount moved to here (compare op_id) */
+};
+
+#define NOTIFY_MOUNT_IN_SUBTREE		WATCH_INFO_FLAG_0 /* Event not actually at watched dentry */
+#define NOTIFY_MOUNT_IS_RECURSIVE	WATCH_INFO_FLAG_1 /* Change applied recursively */
+#define NOTIFY_MOUNT_IS_NOW_RO		WATCH_INFO_FLAG_2 /* Mount changed to R/O */
+#define NOTIFY_MOUNT_IS_SUBMOUNT	WATCH_INFO_FLAG_3 /* New mount is submount */
+
+/*
+ * Mount topology/configuration change notification record.
+ * - watch.type = WATCH_TYPE_MOUNT_NOTIFY
+ * - watch.subtype = enum mount_notification_subtype
+ */
+struct mount_notification {
+	struct watch_notification watch; /* WATCH_TYPE_MOUNT_NOTIFY */
+	__u32	triggered_on;		/* The mount that the notify was on */
+	__u32	changed_mount;		/* The mount that got changed */
+};
+
 #endif /* _UAPI_LINUX_WATCH_QUEUE_H */
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 3b69a560a7ac..3e1c5c9d2efe 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -85,6 +85,9 @@ COND_SYSCALL(ioprio_get);
 /* fs/locks.c */
 COND_SYSCALL(flock);
 
+/* fs/mount_notify.c */
+COND_SYSCALL(watch_mount);
+
 /* fs/namei.c */
 
 /* fs/namespace.c */
