1#include <linux/mount.h>
  2#include <linux/seq_file.h>
  3#include <linux/poll.h>
  4#include <linux/ns_common.h>
  5#include <linux/fs_pin.h>
  6
  7struct mnt_namespace {
  8	atomic_t		count;
  9	struct ns_common	ns;
 10	struct mount *	root;
 11	struct list_head	list;
 12	struct user_namespace	*user_ns;
 13	u64			seq;	/* Sequence number to prevent loops */
 14	wait_queue_head_t poll;
 15	u64 event;
 16};
 17
 18struct mnt_pcp {
 19	int mnt_count;
 20	int mnt_writers;
 21};
 22
 23struct mountpoint {
 24	struct hlist_node m_hash;
 25	struct dentry *m_dentry;
 26	struct hlist_head m_list;
 27	int m_count;
 28};
 29
 30struct mount {
 31	struct hlist_node mnt_hash;
 32	struct mount *mnt_parent;
 33	struct dentry *mnt_mountpoint;
 34	struct vfsmount mnt;
 35	union {
 36		struct rcu_head mnt_rcu;
 37		struct llist_node mnt_llist;
 38	};
 39#ifdef CONFIG_SMP
 40	struct mnt_pcp __percpu *mnt_pcp;
 41#else
 42	int mnt_count;
 43	int mnt_writers;
 44#endif
 45	struct list_head mnt_mounts;	/* list of children, anchored here */
 46	struct list_head mnt_child;	/* and going through their mnt_child */
 47	struct list_head mnt_instance;	/* mount instance on sb->s_mounts */
 48	const char *mnt_devname;	/* Name of device e.g. /dev/dsk/hda1 */
 49	struct list_head mnt_list;
 50	struct list_head mnt_expire;	/* link in fs-specific expiry list */
 51	struct list_head mnt_share;	/* circular list of shared mounts */
 52	struct list_head mnt_slave_list;/* list of slave mounts */
 53	struct list_head mnt_slave;	/* slave list entry */
 54	struct mount *mnt_master;	/* slave is on master->mnt_slave_list */
 55	struct mnt_namespace *mnt_ns;	/* containing namespace */
 56	struct mountpoint *mnt_mp;	/* where is it mounted */
 57	struct hlist_node mnt_mp_list;	/* list mounts with the same mountpoint */
 58#ifdef CONFIG_FSNOTIFY
 59	struct hlist_head mnt_fsnotify_marks;
 60	__u32 mnt_fsnotify_mask;
 61#endif
 62	int mnt_id;			/* mount identifier */
 63	int mnt_group_id;		/* peer group identifier */
 64	int mnt_expiry_mark;		/* true if marked for expiry */
 65	struct hlist_head mnt_pins;
 66	struct fs_pin mnt_umount;
 67	struct dentry *mnt_ex_mountpoint;
 68};
 69
 70#define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
 71
 72static inline struct mount *real_mount(struct vfsmount *mnt)
 73{
 74	return container_of(mnt, struct mount, mnt);
 75}
 76
 77static inline int mnt_has_parent(struct mount *mnt)
 78{
 79	return mnt != mnt->mnt_parent;
 80}
 81
 82static inline int is_mounted(struct vfsmount *mnt)
 83{
 84	/* neither detached nor internal? */
 85	return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
 86}
 87
 88extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
 89extern struct mount *__lookup_mnt_last(struct vfsmount *, struct dentry *);
 90
 91extern int __legitimize_mnt(struct vfsmount *, unsigned);
 92extern bool legitimize_mnt(struct vfsmount *, unsigned);
 93
 94extern void __detach_mounts(struct dentry *dentry);
 95
 96static inline void detach_mounts(struct dentry *dentry)
 97{
 98	if (!d_mountpoint(dentry))
 99		return;
100	__detach_mounts(dentry);
101}
102
103static inline void get_mnt_ns(struct mnt_namespace *ns)
104{
105	atomic_inc(&ns->count);
106}
107
108extern seqlock_t mount_lock;
109
110static inline void lock_mount_hash(void)
111{
112	write_seqlock(&mount_lock);
113}
114
115static inline void unlock_mount_hash(void)
116{
117	write_sequnlock(&mount_lock);
118}
119
120struct proc_mounts {
121	struct mnt_namespace *ns;
122	struct path root;
123	int (*show)(struct seq_file *, struct vfsmount *);
124	void *cached_mount;
125	u64 cached_event;
126	loff_t cached_index;
127};
128
129extern const struct seq_operations mounts_op;
130
131extern bool __is_local_mountpoint(struct dentry *dentry);
132static inline bool is_local_mountpoint(struct dentry *dentry)
133{
134	if (!d_mountpoint(dentry))
135		return false;
136
137	return __is_local_mountpoint(dentry);
138}