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 /*
12 * Traversal and modification of .list is protected by either
13 * - taking namespace_sem for write, OR
14 * - taking namespace_sem for read AND taking .ns_lock.
15 */
16 struct list_head list;
17 spinlock_t ns_lock;
18 struct user_namespace *user_ns;
19 struct ucounts *ucounts;
20 u64 seq; /* Sequence number to prevent loops */
21 wait_queue_head_t poll;
22 u64 event;
23 unsigned int mounts; /* # of mounts in the namespace */
24 unsigned int pending_mounts;
25 } __randomize_layout;
26
27 struct mnt_pcp {
28 int mnt_count;
29 int mnt_writers;
30 };
31
32 struct mountpoint {
33 struct hlist_node m_hash;
34 struct dentry *m_dentry;
35 struct hlist_head m_list;
36 int m_count;
37 };
38
39 struct mount {
40 struct hlist_node mnt_hash;
41 struct mount *mnt_parent;
42 struct dentry *mnt_mountpoint;
43 struct vfsmount mnt;
44 union {
45 struct rcu_head mnt_rcu;
46 struct llist_node mnt_llist;
47 };
48 #ifdef CONFIG_SMP
49 struct mnt_pcp __percpu *mnt_pcp;
50 #else
51 int mnt_count;
52 int mnt_writers;
53 #endif
54 struct list_head mnt_mounts; /* list of children, anchored here */
55 struct list_head mnt_child; /* and going through their mnt_child */
56 struct list_head mnt_instance; /* mount instance on sb->s_mounts */
57 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
58 struct list_head mnt_list;
59 struct list_head mnt_expire; /* link in fs-specific expiry list */
60 struct list_head mnt_share; /* circular list of shared mounts */
61 struct list_head mnt_slave_list;/* list of slave mounts */
62 struct list_head mnt_slave; /* slave list entry */
63 struct mount *mnt_master; /* slave is on master->mnt_slave_list */
64 struct mnt_namespace *mnt_ns; /* containing namespace */
65 struct mountpoint *mnt_mp; /* where is it mounted */
66 union {
67 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */
68 struct hlist_node mnt_umount;
69 };
70 struct list_head mnt_umounting; /* list entry for umount propagation */
71 #ifdef CONFIG_FSNOTIFY
72 struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
73 __u32 mnt_fsnotify_mask;
74 #endif
75 int mnt_id; /* mount identifier */
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
real_mount(struct vfsmount * mnt)84 static inline struct mount *real_mount(struct vfsmount *mnt)
85 {
86 return container_of(mnt, struct mount, mnt);
87 }
88
mnt_has_parent(struct mount * mnt)89 static inline int mnt_has_parent(struct mount *mnt)
90 {
91 return mnt != mnt->mnt_parent;
92 }
93
is_mounted(struct vfsmount * mnt)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 extern bool legitimize_mnt(struct vfsmount *, unsigned);
104
__path_is_mountpoint(const struct path * path)105 static inline bool __path_is_mountpoint(const struct path *path)
106 {
107 struct mount *m = __lookup_mnt(path->mnt, path->dentry);
108 return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
109 }
110
111 extern void __detach_mounts(struct dentry *dentry);
112
detach_mounts(struct dentry * dentry)113 static inline void detach_mounts(struct dentry *dentry)
114 {
115 if (!d_mountpoint(dentry))
116 return;
117 __detach_mounts(dentry);
118 }
119
get_mnt_ns(struct mnt_namespace * ns)120 static inline void get_mnt_ns(struct mnt_namespace *ns)
121 {
122 refcount_inc(&ns->ns.count);
123 }
124
125 extern seqlock_t mount_lock;
126
127 struct proc_mounts {
128 struct mnt_namespace *ns;
129 struct path root;
130 int (*show)(struct seq_file *, struct vfsmount *);
131 struct mount cursor;
132 };
133
134 extern const struct seq_operations mounts_op;
135
136 extern bool __is_local_mountpoint(struct dentry *dentry);
is_local_mountpoint(struct dentry * dentry)137 static inline bool is_local_mountpoint(struct dentry *dentry)
138 {
139 if (!d_mountpoint(dentry))
140 return false;
141
142 return __is_local_mountpoint(dentry);
143 }
144
is_anon_ns(struct mnt_namespace * ns)145 static inline bool is_anon_ns(struct mnt_namespace *ns)
146 {
147 return ns->seq == 0;
148 }
149
150 extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor);
151