1 files changed, 194 insertions, 24 deletions

diff --git a/fs/mount.h b/fs/mount.h
index 64a858143ff9..2d28ef2a3aed 100644
--- a/fs/mount.h
+++ b/fs/mount.h
@@ -1,17 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #include <linux/mount.h>
 #include <linux/seq_file.h>
 #include <linux/poll.h>
+#include <linux/ns_common.h>
+#include <linux/fs_pin.h>
+
+extern struct list_head notify_list;
 
 struct mnt_namespace {
-	atomic_t		count;
-	unsigned int		proc_inum;
+	struct ns_common	ns;
 	struct mount *	root;
-	struct list_head	list;
+	struct {
+		struct rb_root	mounts;		 /* Protected by namespace_sem */
+		struct rb_node	*mnt_last_node;	 /* last (rightmost) mount in the rbtree */
+		struct rb_node	*mnt_first_node; /* first (leftmost) mount in the rbtree */
+	};
 	struct user_namespace	*user_ns;
-	u64			seq;	/* Sequence number to prevent loops */
-	wait_queue_head_t poll;
-	int event;
-};
+	struct ucounts		*ucounts;
+	wait_queue_head_t	poll;
+	u64			seq_origin; /* Sequence number of origin mount namespace */
+	u64 event;
+#ifdef CONFIG_FSNOTIFY
+	__u32			n_fsnotify_mask;
+	struct fsnotify_mark_connector __rcu *n_fsnotify_marks;
+#endif
+	unsigned int		nr_mounts; /* # of mounts in the namespace */
+	unsigned int		pending_mounts;
+	refcount_t		passive; /* number references not pinning @mounts */
+	bool			is_anon;
+} __randomize_layout;
 
 struct mnt_pcp {
 	int mnt_count;
@@ -19,16 +36,21 @@ struct mnt_pcp {
 };
 
 struct mountpoint {
-	struct list_head m_hash;
+	struct hlist_node m_hash;
 	struct dentry *m_dentry;
-	int m_count;
+	struct hlist_head m_list;
 };
 
 struct mount {
-	struct list_head mnt_hash;
+	struct hlist_node mnt_hash;
 	struct mount *mnt_parent;
 	struct dentry *mnt_mountpoint;
 	struct vfsmount mnt;
+	union {
+		struct rb_node mnt_node; /* node in the ns->mounts rbtree */
+		struct rcu_head mnt_rcu;
+		struct llist_node mnt_llist;
+	};
 #ifdef CONFIG_SMP
 	struct mnt_pcp __percpu *mnt_pcp;
 #else
@@ -37,25 +59,53 @@ struct mount {
 #endif
 	struct list_head mnt_mounts;	/* list of children, anchored here */
 	struct list_head mnt_child;	/* and going through their mnt_child */
-	struct list_head mnt_instance;	/* mount instance on sb->s_mounts */
+	struct mount *mnt_next_for_sb;	/* the next two fields are hlist_node, */
+	struct mount * __aligned(1) *mnt_pprev_for_sb;
+					/* except that LSB of pprev is stolen */
+#define WRITE_HOLD 1			/* ... for use by mnt_hold_writers() */
 	const char *mnt_devname;	/* Name of device e.g. /dev/dsk/hda1 */
 	struct list_head mnt_list;
 	struct list_head mnt_expire;	/* link in fs-specific expiry list */
 	struct list_head mnt_share;	/* circular list of shared mounts */
-	struct list_head mnt_slave_list;/* list of slave mounts */
-	struct list_head mnt_slave;	/* slave list entry */
+	struct hlist_head mnt_slave_list;/* list of slave mounts */
+	struct hlist_node mnt_slave;	/* slave list entry */
 	struct mount *mnt_master;	/* slave is on master->mnt_slave_list */
 	struct mnt_namespace *mnt_ns;	/* containing namespace */
 	struct mountpoint *mnt_mp;	/* where is it mounted */
+	union {
+		struct hlist_node mnt_mp_list;	/* list mounts with the same mountpoint */
+		struct hlist_node mnt_umount;
+	};
 #ifdef CONFIG_FSNOTIFY
-	struct hlist_head mnt_fsnotify_marks;
+	struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
 	__u32 mnt_fsnotify_mask;
+	struct list_head to_notify;	/* need to queue notification */
+	struct mnt_namespace *prev_ns;	/* previous namespace (NULL if none) */
 #endif
-	int mnt_id;			/* mount identifier */
+	int mnt_t_flags;		/* namespace_sem-protected flags */
+	int mnt_id;			/* mount identifier, reused */
+	u64 mnt_id_unique;		/* mount ID unique until reboot */
 	int mnt_group_id;		/* peer group identifier */
 	int mnt_expiry_mark;		/* true if marked for expiry */
-	int mnt_pinned;
-	int mnt_ghosts;
+	struct hlist_head mnt_pins;
+	struct hlist_head mnt_stuck_children;
+	struct mount *overmount;	/* mounted on ->mnt_root */
+} __randomize_layout;
+
+enum {
+	T_SHARED		= 1, /* mount is shared */
+	T_UNBINDABLE		= 2, /* mount is unbindable */
+	T_MARKED		= 4, /* internal mark for propagate_... */
+	T_UMOUNT_CANDIDATE	= 8, /* for propagate_umount */
+
+	/*
+	 * T_SHARED_MASK is the set of flags that should be cleared when a
+	 * mount becomes shared.  Currently, this is only the flag that says a
+	 * mount cannot be bind mounted, since this is how we create a mount
+	 * that shares events with another mount.  If you add a new T_*
+	 * flag, consider how it interacts with shared mounts.
+	 */
+	T_SHARED_MASK	= T_UNBINDABLE,
 };
 
 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
@@ -65,7 +115,7 @@ static inline struct mount *real_mount(struct vfsmount *mnt)
 	return container_of(mnt, struct mount, mnt);
 }
 
-static inline int mnt_has_parent(struct mount *mnt)
+static inline int mnt_has_parent(const struct mount *mnt)
 {
 	return mnt != mnt->mnt_parent;
 }
@@ -73,23 +123,143 @@ static inline int mnt_has_parent(struct mount *mnt)
 static inline int is_mounted(struct vfsmount *mnt)
 {
 	/* neither detached nor internal? */
-	return !IS_ERR_OR_NULL(real_mount(mnt));
+	return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
 }
 
-extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *, int);
+extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
+
+extern int __legitimize_mnt(struct vfsmount *, unsigned);
+
+static inline bool __path_is_mountpoint(const struct path *path)
+{
+	struct mount *m = __lookup_mnt(path->mnt, path->dentry);
+	return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
+}
+
+extern void __detach_mounts(struct dentry *dentry);
+
+static inline void detach_mounts(struct dentry *dentry)
+{
+	if (!d_mountpoint(dentry))
+		return;
+	__detach_mounts(dentry);
+}
 
 static inline void get_mnt_ns(struct mnt_namespace *ns)
 {
-	atomic_inc(&ns->count);
+	ns_ref_inc(ns);
 }
 
+extern seqlock_t mount_lock;
+
+DEFINE_LOCK_GUARD_0(mount_writer, write_seqlock(&mount_lock),
+		    write_sequnlock(&mount_lock))
+DEFINE_LOCK_GUARD_0(mount_locked_reader, read_seqlock_excl(&mount_lock),
+		    read_sequnlock_excl(&mount_lock))
+
 struct proc_mounts {
-	struct seq_file m;
 	struct mnt_namespace *ns;
 	struct path root;
 	int (*show)(struct seq_file *, struct vfsmount *);
 };
 
-#define proc_mounts(p) (container_of((p), struct proc_mounts, m))
-
 extern const struct seq_operations mounts_op;
+
+extern bool __is_local_mountpoint(const struct dentry *dentry);
+static inline bool is_local_mountpoint(const struct dentry *dentry)
+{
+	if (!d_mountpoint(dentry))
+		return false;
+
+	return __is_local_mountpoint(dentry);
+}
+
+static inline bool is_anon_ns(struct mnt_namespace *ns)
+{
+	return ns->is_anon;
+}
+
+static inline bool anon_ns_root(const struct mount *m)
+{
+	struct mnt_namespace *ns = READ_ONCE(m->mnt_ns);
+
+	return !IS_ERR_OR_NULL(ns) && is_anon_ns(ns) && m == ns->root;
+}
+
+static inline bool mnt_ns_attached(const struct mount *mnt)
+{
+	return !RB_EMPTY_NODE(&mnt->mnt_node);
+}
+
+static inline bool mnt_ns_empty(const struct mnt_namespace *ns)
+{
+	return RB_EMPTY_ROOT(&ns->mounts);
+}
+
+static inline void move_from_ns(struct mount *mnt)
+{
+	struct mnt_namespace *ns = mnt->mnt_ns;
+	WARN_ON(!mnt_ns_attached(mnt));
+	if (ns->mnt_last_node == &mnt->mnt_node)
+		ns->mnt_last_node = rb_prev(&mnt->mnt_node);
+	if (ns->mnt_first_node == &mnt->mnt_node)
+		ns->mnt_first_node = rb_next(&mnt->mnt_node);
+	rb_erase(&mnt->mnt_node, &ns->mounts);
+	RB_CLEAR_NODE(&mnt->mnt_node);
+}
+
+bool has_locked_children(struct mount *mnt, struct dentry *dentry);
+struct mnt_namespace *get_sequential_mnt_ns(struct mnt_namespace *mnt_ns,
+					    bool previous);
+
+static inline struct mnt_namespace *to_mnt_ns(struct ns_common *ns)
+{
+	return container_of(ns, struct mnt_namespace, ns);
+}
+
+#ifdef CONFIG_FSNOTIFY
+static inline void mnt_notify_add(struct mount *m)
+{
+	/* Optimize the case where there are no watches */
+	if ((m->mnt_ns && m->mnt_ns->n_fsnotify_marks) ||
+	    (m->prev_ns && m->prev_ns->n_fsnotify_marks))
+		list_add_tail(&m->to_notify, &notify_list);
+	else
+		m->prev_ns = m->mnt_ns;
+}
+#else
+static inline void mnt_notify_add(struct mount *m)
+{
+}
+#endif
+
+static inline struct mount *topmost_overmount(struct mount *m)
+{
+	while (m->overmount)
+		m = m->overmount;
+	return m;
+}
+
+static inline bool __test_write_hold(struct mount * __aligned(1) *val)
+{
+	return (unsigned long)val & WRITE_HOLD;
+}
+
+static inline bool test_write_hold(const struct mount *m)
+{
+	return __test_write_hold(m->mnt_pprev_for_sb);
+}
+
+static inline void set_write_hold(struct mount *m)
+{
+	m->mnt_pprev_for_sb = (void *)((unsigned long)m->mnt_pprev_for_sb
+				       | WRITE_HOLD);
+}
+
+static inline void clear_write_hold(struct mount *m)
+{
+	m->mnt_pprev_for_sb = (void *)((unsigned long)m->mnt_pprev_for_sb
+				       & ~WRITE_HOLD);
+}
+
+struct mnt_namespace *mnt_ns_from_dentry(struct dentry *dentry);