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
8 struct 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
21 struct mnt_pcp {
22 int mnt_count;
23 int mnt_writers;
24 };
25
26 struct mountpoint {
27 struct hlist_node m_hash;
28 struct dentry *m_dentry;
29 struct hlist_head m_list;
30 int m_count;
31 };
32
33 struct 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
real_mount(struct vfsmount * mnt)82 static inline struct mount *real_mount(struct vfsmount *mnt)
83 {
84 return container_of(mnt, struct mount, mnt);
85 }
86
mnt_has_parent(struct mount * mnt)87 static inline int mnt_has_parent(struct mount *mnt)
88 {
89 return mnt != mnt->mnt_parent;
90 }
91
is_mounted(struct vfsmount * mnt)92 static 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
98 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
99
100 extern int __legitimize_mnt(struct vfsmount *, unsigned);
101
__path_is_mountpoint(const struct path * path)102 static 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
108 extern void __detach_mounts(struct dentry *dentry);
109
detach_mounts(struct dentry * dentry)110 static inline void detach_mounts(struct dentry *dentry)
111 {
112 if (!d_mountpoint(dentry))
113 return;
114 __detach_mounts(dentry);
115 }
116
get_mnt_ns(struct mnt_namespace * ns)117 static inline void get_mnt_ns(struct mnt_namespace *ns)
118 {
119 refcount_inc(&ns->ns.count);
120 }
121
122 extern seqlock_t mount_lock;
123
124 struct proc_mounts {
125 struct mnt_namespace *ns;
126 struct path root;
127 int (*show)(struct seq_file *, struct vfsmount *);
128 };
129
130 extern const struct seq_operations mounts_op;
131
132 extern bool __is_local_mountpoint(struct dentry *dentry);
is_local_mountpoint(struct dentry * dentry)133 static 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
is_anon_ns(struct mnt_namespace * ns)141 static inline bool is_anon_ns(struct mnt_namespace *ns)
142 {
143 return ns->seq == 0;
144 }
145
move_from_ns(struct mount * mnt,struct list_head * dt_list)146 static 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
154 extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor);
155