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[mirror_ubuntu-bionic-kernel.git] / fs / mount.h
1 #include <linux/mount.h>
2 #include <linux/seq_file.h>
3 #include <linux/poll.h>
4 #include <linux/ns_common.h>
5 #include <linux/fs_pin.h>
6
7 struct mnt_namespace {
8 atomic_t count;
9 struct ns_common ns;
10 struct mount * root;
11 struct list_head list;
12 struct user_namespace *user_ns;
13 u64 seq; /* Sequence number to prevent loops */
14 wait_queue_head_t poll;
15 u64 event;
16 };
17
18 struct mnt_pcp {
19 int mnt_count;
20 int mnt_writers;
21 };
22
23 struct mountpoint {
24 struct hlist_node m_hash;
25 struct dentry *m_dentry;
26 struct hlist_head m_list;
27 int m_count;
28 };
29
30 struct mount {
31 struct hlist_node mnt_hash;
32 struct mount *mnt_parent;
33 struct dentry *mnt_mountpoint;
34 struct vfsmount mnt;
35 union {
36 struct rcu_head mnt_rcu;
37 struct llist_node mnt_llist;
38 };
39 #ifdef CONFIG_SMP
40 struct mnt_pcp __percpu *mnt_pcp;
41 #else
42 int mnt_count;
43 int mnt_writers;
44 #endif
45 struct list_head mnt_mounts; /* list of children, anchored here */
46 struct list_head mnt_child; /* and going through their mnt_child */
47 struct list_head mnt_instance; /* mount instance on sb->s_mounts */
48 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */
49 struct list_head mnt_list;
50 struct list_head mnt_expire; /* link in fs-specific expiry list */
51 struct list_head mnt_share; /* circular list of shared mounts */
52 struct list_head mnt_slave_list;/* list of slave mounts */
53 struct list_head mnt_slave; /* slave list entry */
54 struct mount *mnt_master; /* slave is on master->mnt_slave_list */
55 struct mnt_namespace *mnt_ns; /* containing namespace */
56 struct mountpoint *mnt_mp; /* where is it mounted */
57 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */
58 #ifdef CONFIG_FSNOTIFY
59 struct hlist_head mnt_fsnotify_marks;
60 __u32 mnt_fsnotify_mask;
61 #endif
62 int mnt_id; /* mount identifier */
63 int mnt_group_id; /* peer group identifier */
64 int mnt_expiry_mark; /* true if marked for expiry */
65 struct hlist_head mnt_pins;
66 struct fs_pin mnt_umount;
67 struct dentry *mnt_ex_mountpoint;
68 };
69
70 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
71
72 static inline struct mount *real_mount(struct vfsmount *mnt)
73 {
74 return container_of(mnt, struct mount, mnt);
75 }
76
77 static inline int mnt_has_parent(struct mount *mnt)
78 {
79 return mnt != mnt->mnt_parent;
80 }
81
82 static inline int is_mounted(struct vfsmount *mnt)
83 {
84 /* neither detached nor internal? */
85 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
86 }
87
88 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
89 extern struct mount *__lookup_mnt_last(struct vfsmount *, struct dentry *);
90
91 extern bool legitimize_mnt(struct vfsmount *, unsigned);
92
93 extern void __detach_mounts(struct dentry *dentry);
94
95 static inline void detach_mounts(struct dentry *dentry)
96 {
97 if (!d_mountpoint(dentry))
98 return;
99 __detach_mounts(dentry);
100 }
101
102 static inline void get_mnt_ns(struct mnt_namespace *ns)
103 {
104 atomic_inc(&ns->count);
105 }
106
107 extern seqlock_t mount_lock;
108
109 static inline void lock_mount_hash(void)
110 {
111 write_seqlock(&mount_lock);
112 }
113
114 static inline void unlock_mount_hash(void)
115 {
116 write_sequnlock(&mount_lock);
117 }
118
119 struct proc_mounts {
120 struct seq_file m;
121 struct mnt_namespace *ns;
122 struct path root;
123 int (*show)(struct seq_file *, struct vfsmount *);
124 void *cached_mount;
125 u64 cached_event;
126 loff_t cached_index;
127 };
128
129 #define proc_mounts(p) (container_of((p), struct proc_mounts, m))
130
131 extern const struct seq_operations mounts_op;
132
133 extern bool __is_local_mountpoint(struct dentry *dentry);
134 static inline bool is_local_mountpoint(struct dentry *dentry)
135 {
136 if (!d_mountpoint(dentry))
137 return false;
138
139 return __is_local_mountpoint(dentry);
140 }