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