1/* SPDX-License-Identifier: GPL-2.0 */
2#include <linux/mount.h>
3#include <linux/seq_file.h>
4#include <linux/poll.h>
5#include <linux/ns_common.h>
6#include <linux/fs_pin.h>
7
8struct mnt_namespace {
9	struct ns_common	ns;
10	struct mount *	root;
11	struct rb_root		mounts; /* Protected by namespace_sem */
12	struct user_namespace	*user_ns;
13	struct ucounts		*ucounts;
14	u64			seq;	/* Sequence number to prevent loops */
15	wait_queue_head_t poll;
16	u64 event;
17	unsigned int		nr_mounts; /* # of mounts in the namespace */
18	unsigned int		pending_mounts;
19} __randomize_layout;
20
21struct mnt_pcp {
22	int mnt_count;
23	int mnt_writers;
24};
25
26struct mountpoint {
27	struct hlist_node m_hash;
28	struct dentry *m_dentry;
29	struct hlist_head m_list;
30	int m_count;
31};
32
33struct mount {
34	struct hlist_node mnt_hash;
35	struct mount *mnt_parent;
36	struct dentry *mnt_mountpoint;
37	struct vfsmount mnt;
38	union {
39		struct rcu_head mnt_rcu;
40		struct llist_node mnt_llist;
41	};
42#ifdef CONFIG_SMP
43	struct mnt_pcp __percpu *mnt_pcp;
44#else
45	int mnt_count;
46	int mnt_writers;
47#endif
48	struct list_head mnt_mounts;	/* list of children, anchored here */
49	struct list_head mnt_child;	/* and going through their mnt_child */
50	struct list_head mnt_instance;	/* mount instance on sb->s_mounts */
51	const char *mnt_devname;	/* Name of device e.g. /dev/dsk/hda1 */
52	union {
53		struct rb_node mnt_node;	/* Under ns->mounts */
54		struct list_head mnt_list;
55	};
56	struct list_head mnt_expire;	/* link in fs-specific expiry list */
57	struct list_head mnt_share;	/* circular list of shared mounts */
58	struct list_head mnt_slave_list;/* list of slave mounts */
59	struct list_head mnt_slave;	/* slave list entry */
60	struct mount *mnt_master;	/* slave is on master->mnt_slave_list */
61	struct mnt_namespace *mnt_ns;	/* containing namespace */
62	struct mountpoint *mnt_mp;	/* where is it mounted */
63	union {
64		struct hlist_node mnt_mp_list;	/* list mounts with the same mountpoint */
65		struct hlist_node mnt_umount;
66	};
67	struct list_head mnt_umounting; /* list entry for umount propagation */
68#ifdef CONFIG_FSNOTIFY
69	struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
70	__u32 mnt_fsnotify_mask;
71#endif
72	int mnt_id;			/* mount identifier, reused */
73	u64 mnt_id_unique;		/* mount ID unique until reboot */
74	int mnt_group_id;		/* peer group identifier */
75	int mnt_expiry_mark;		/* true if marked for expiry */
76	struct hlist_head mnt_pins;
77	struct hlist_head mnt_stuck_children;
78} __randomize_layout;
79
80#define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
81
82static inline struct mount *real_mount(struct vfsmount *mnt)
83{
84	return container_of(mnt, struct mount, mnt);
85}
86
87static inline int mnt_has_parent(struct mount *mnt)
88{
89	return mnt != mnt->mnt_parent;
90}
91
92static inline int is_mounted(struct vfsmount *mnt)
93{
94	/* neither detached nor internal? */
95	return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
96}
97
98extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
99
100extern int __legitimize_mnt(struct vfsmount *, unsigned);
101
102static inline bool __path_is_mountpoint(const struct path *path)
103{
104	struct mount *m = __lookup_mnt(path->mnt, path->dentry);
105	return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
106}
107
108extern void __detach_mounts(struct dentry *dentry);
109
110static inline void detach_mounts(struct dentry *dentry)
111{
112	if (!d_mountpoint(dentry))
113		return;
114	__detach_mounts(dentry);
115}
116
117static inline void get_mnt_ns(struct mnt_namespace *ns)
118{
119	refcount_inc(&ns->ns.count);
120}
121
122extern seqlock_t mount_lock;
123
124struct proc_mounts {
125	struct mnt_namespace *ns;
126	struct path root;
127	int (*show)(struct seq_file *, struct vfsmount *);
128};
129
130extern const struct seq_operations mounts_op;
131
132extern bool __is_local_mountpoint(struct dentry *dentry);
133static inline bool is_local_mountpoint(struct dentry *dentry)
134{
135	if (!d_mountpoint(dentry))
136		return false;
137
138	return __is_local_mountpoint(dentry);
139}
140
141static inline bool is_anon_ns(struct mnt_namespace *ns)
142{
143	return ns->seq == 0;
144}
145
146static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list)
147{
148	WARN_ON(!(mnt->mnt.mnt_flags & MNT_ONRB));
149	mnt->mnt.mnt_flags &= ~MNT_ONRB;
150	rb_erase(&mnt->mnt_node, &mnt->mnt_ns->mounts);
151	list_add_tail(&mnt->mnt_list, dt_list);
152}
153
154extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor);
155