/* 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>

  
  struct mnt_namespace {
  	atomic_t		count;

  	struct ns_common	ns;

  	struct mount *	root;

  	/*
  	 * Traversal and modification of .list is protected by either
  	 * - taking namespace_sem for write, OR
  	 * - taking namespace_sem for read AND taking .ns_lock.
  	 */

  	struct list_head	list;

  	spinlock_t		ns_lock;

  	struct user_namespace	*user_ns;

  	struct ucounts		*ucounts;

  	u64			seq;	/* Sequence number to prevent loops */

  	wait_queue_head_t poll;

  	u64 event;

  	unsigned int		mounts; /* # of mounts in the namespace */
  	unsigned int		pending_mounts;

  } __randomize_layout;

  struct mnt_pcp {
  	int mnt_count;
  	int mnt_writers;
  };

  struct mountpoint {

  	struct hlist_node m_hash;

  	struct dentry *m_dentry;

  	struct hlist_head m_list;

  	int m_count;
  };

  struct mount {

  	struct hlist_node mnt_hash;

  	struct mount *mnt_parent;

  	struct dentry *mnt_mountpoint;

  	struct vfsmount mnt;

  	union {
  		struct rcu_head mnt_rcu;
  		struct llist_node mnt_llist;
  	};

  #ifdef CONFIG_SMP
  	struct mnt_pcp __percpu *mnt_pcp;

  #else
  	int mnt_count;
  	int mnt_writers;
  #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 */

  	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 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;
  	};

  	struct list_head mnt_umounting; /* list entry for umount propagation */

  #ifdef CONFIG_FSNOTIFY

  	struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;

  	__u32 mnt_fsnotify_mask;
  #endif

  	int mnt_id;			/* mount identifier */
  	int mnt_group_id;		/* peer group identifier */

  	int mnt_expiry_mark;		/* true if marked for expiry */

  	struct hlist_head mnt_pins;

  	struct hlist_head mnt_stuck_children;

  } __randomize_layout;

  #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */

  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)

  {

  	return mnt != mnt->mnt_parent;

  }

  static inline int is_mounted(struct vfsmount *mnt)
  {
  	/* neither detached nor internal? */

  	return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);

  }

  extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);

  extern int __legitimize_mnt(struct vfsmount *, unsigned);

  extern bool 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);
  }

  extern seqlock_t mount_lock;

  
  static inline void lock_mount_hash(void)
  {

  	write_seqlock(&mount_lock);

  }
  
  static inline void unlock_mount_hash(void)
  {

  	write_sequnlock(&mount_lock);

  }

  struct proc_mounts {

  	struct mnt_namespace *ns;
  	struct path root;
  	int (*show)(struct seq_file *, struct vfsmount *);

  	struct mount cursor;

  };
  
  extern const struct seq_operations mounts_op;

  
  extern bool __is_local_mountpoint(struct dentry *dentry);
  static inline bool is_local_mountpoint(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->seq == 0;
  }

  
  extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor);