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 struct rb_node mnt_ns_tree_node; /* node in the mnt_ns_tree */
20 refcount_t passive; /* number references not pinning @mounts */
21 } __randomize_layout;
22
23 struct mnt_pcp {
24 int mnt_count;
25 int mnt_writers;
26 };
27
28 struct mountpoint {
29 struct hlist_node m_hash;
30 struct dentry *m_dentry;
31 struct hlist_head m_list;
32 int m_count;
33 };
34
35 struct mount {
36 struct hlist_node mnt_hash;
37 struct mount *mnt_parent;
38 struct dentry *mnt_mountpoint;
39 struct vfsmount mnt;
40 union {
41 struct rcu_head mnt_rcu;
42 struct llist_node mnt_llist;
43 };
44 #ifdef CONFIG_SMP
45 struct mnt_pcp __percpu *mnt_pcp;
46 #else
47 int mnt_count;
48 int mnt_writers;
49 #endif
50 struct list_head mnt_mounts; /* list of children, anchored here */
51 struct list_head mnt_child; /* and going through their mnt_child */
52 struct list_head mnt_instance; /* mount instance on sb->s_mounts */
53 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
54 union {
55 struct rb_node mnt_node; /* Under ns->mounts */
56 struct list_head mnt_list;
57 };
58 struct list_head mnt_expire; /* link in fs-specific expiry list */
59 struct list_head mnt_share; /* circular list of shared mounts */
60 struct list_head mnt_slave_list;/* list of slave mounts */
61 struct list_head mnt_slave; /* slave list entry */
62 struct mount *mnt_master; /* slave is on master->mnt_slave_list */
63 struct mnt_namespace *mnt_ns; /* containing namespace */
64 struct mountpoint *mnt_mp; /* where is it mounted */
65 union {
66 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */
67 struct hlist_node mnt_umount;
68 };
69 struct list_head mnt_umounting; /* list entry for umount propagation */
70 #ifdef CONFIG_FSNOTIFY
71 struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
72 __u32 mnt_fsnotify_mask;
73 #endif
74 int mnt_id; /* mount identifier, reused */
75 u64 mnt_id_unique; /* mount ID unique until reboot */
76 int mnt_group_id; /* peer group identifier */
77 int mnt_expiry_mark; /* true if marked for expiry */
78 struct hlist_head mnt_pins;
79 struct hlist_head mnt_stuck_children;
80 } __randomize_layout;
81
82 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
83
84 static inline struct mount *real_mount(struct vfsmount *mnt)
85 {
86 return container_of(mnt, struct mount, mnt);
87 }
88
89 static inline int mnt_has_parent(struct mount *mnt)
90 {
91 return mnt != mnt->mnt_parent;
92 }
93
94 static inline int is_mounted(struct vfsmount *mnt)
95 {
96 /* neither detached nor internal? */
97 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
98 }
99
100 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
101
102 extern int __legitimize_mnt(struct vfsmount *, unsigned);
103
104 static inline bool __path_is_mountpoint(const struct path *path)
105 {
106 struct mount *m = __lookup_mnt(path->mnt, path->dentry);
107 return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
108 }
109
110 extern void __detach_mounts(struct dentry *dentry);
111
112 static inline void detach_mounts(struct dentry *dentry)
113 {
114 if (!d_mountpoint(dentry))
115 return;
116 __detach_mounts(dentry);
117 }
118
119 static inline void get_mnt_ns(struct mnt_namespace *ns)
120 {
121 refcount_inc(&ns->ns.count);
122 }
123
124 extern seqlock_t mount_lock;
125
126 struct proc_mounts {
127 struct mnt_namespace *ns;
128 struct path root;
129 int (*show)(struct seq_file *, struct vfsmount *);
130 };
131
132 extern const struct seq_operations mounts_op;
133
134 extern bool __is_local_mountpoint(struct dentry *dentry);
135 static inline bool is_local_mountpoint(struct dentry *dentry)
136 {
137 if (!d_mountpoint(dentry))
138 return false;
139
140 return __is_local_mountpoint(dentry);
141 }
142
143 static inline bool is_anon_ns(struct mnt_namespace *ns)
144 {
145 return ns->seq == 0;
146 }
147
148 static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list)
149 {
150 WARN_ON(!(mnt->mnt.mnt_flags & MNT_ONRB));
151 mnt->mnt.mnt_flags &= ~MNT_ONRB;
152 rb_erase(&mnt->mnt_node, &mnt->mnt_ns->mounts);
153 list_add_tail(&mnt->mnt_list, dt_list);
154 }
155
156 extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor);
157 bool has_locked_children(struct mount *mnt, struct dentry *dentry);
158
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