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 bool legitimize_mnt(struct vfsmount *, unsigned);
92
93extern void __detach_mounts(struct dentry *dentry);
94
95static inline void detach_mounts(struct dentry *dentry)
96{
97	if (!d_mountpoint(dentry))
98		return;
99	__detach_mounts(dentry);
100}
101
102static inline void get_mnt_ns(struct mnt_namespace *ns)
103{
104	atomic_inc(&ns->count);
105}
106
107extern seqlock_t mount_lock;
108
109static inline void lock_mount_hash(void)
110{
111	write_seqlock(&mount_lock);
112}
113
114static inline void unlock_mount_hash(void)
115{
116	write_sequnlock(&mount_lock);
117}
118
119struct proc_mounts {
120	struct seq_file m;
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
129#define proc_mounts(p) (container_of((p), struct proc_mounts, m))
130
131extern const struct seq_operations mounts_op;
132
133extern bool __is_local_mountpoint(struct dentry *dentry);
134static inline bool is_local_mountpoint(struct dentry *dentry)
135{
136	if (!d_mountpoint(dentry))
137		return false;
138
139	return __is_local_mountpoint(dentry);
140}
141