xref: /openbmc/linux/fs/mount.h (revision e917ba44)
1 #include <linux/mount.h>
2 #include <linux/seq_file.h>
3 #include <linux/poll.h>
4 
5 struct mnt_namespace {
6 	atomic_t		count;
7 	unsigned int		proc_inum;
8 	struct mount *	root;
9 	struct list_head	list;
10 	struct user_namespace	*user_ns;
11 	u64			seq;	/* Sequence number to prevent loops */
12 	wait_queue_head_t poll;
13 	u64 event;
14 };
15 
16 struct mnt_pcp {
17 	int mnt_count;
18 	int mnt_writers;
19 };
20 
21 struct mountpoint {
22 	struct hlist_node m_hash;
23 	struct dentry *m_dentry;
24 	int m_count;
25 };
26 
27 struct mount {
28 	struct hlist_node mnt_hash;
29 	struct mount *mnt_parent;
30 	struct dentry *mnt_mountpoint;
31 	struct vfsmount mnt;
32 	struct rcu_head mnt_rcu;
33 #ifdef CONFIG_SMP
34 	struct mnt_pcp __percpu *mnt_pcp;
35 #else
36 	int mnt_count;
37 	int mnt_writers;
38 #endif
39 	struct list_head mnt_mounts;	/* list of children, anchored here */
40 	struct list_head mnt_child;	/* and going through their mnt_child */
41 	struct list_head mnt_instance;	/* mount instance on sb->s_mounts */
42 	const char *mnt_devname;	/* Name of device e.g. /dev/dsk/hda1 */
43 	struct list_head mnt_list;
44 	struct list_head mnt_expire;	/* link in fs-specific expiry list */
45 	struct list_head mnt_share;	/* circular list of shared mounts */
46 	struct list_head mnt_slave_list;/* list of slave mounts */
47 	struct list_head mnt_slave;	/* slave list entry */
48 	struct mount *mnt_master;	/* slave is on master->mnt_slave_list */
49 	struct mnt_namespace *mnt_ns;	/* containing namespace */
50 	struct mountpoint *mnt_mp;	/* where is it mounted */
51 #ifdef CONFIG_FSNOTIFY
52 	struct hlist_head mnt_fsnotify_marks;
53 	__u32 mnt_fsnotify_mask;
54 #endif
55 	int mnt_id;			/* mount identifier */
56 	int mnt_group_id;		/* peer group identifier */
57 	int mnt_expiry_mark;		/* true if marked for expiry */
58 	struct hlist_head mnt_pins;
59 	struct path mnt_ex_mountpoint;
60 };
61 
62 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
63 
64 static inline struct mount *real_mount(struct vfsmount *mnt)
65 {
66 	return container_of(mnt, struct mount, mnt);
67 }
68 
69 static inline int mnt_has_parent(struct mount *mnt)
70 {
71 	return mnt != mnt->mnt_parent;
72 }
73 
74 static inline int is_mounted(struct vfsmount *mnt)
75 {
76 	/* neither detached nor internal? */
77 	return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
78 }
79 
80 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
81 extern struct mount *__lookup_mnt_last(struct vfsmount *, struct dentry *);
82 
83 extern bool legitimize_mnt(struct vfsmount *, unsigned);
84 
85 static inline void get_mnt_ns(struct mnt_namespace *ns)
86 {
87 	atomic_inc(&ns->count);
88 }
89 
90 extern seqlock_t mount_lock;
91 
92 static inline void lock_mount_hash(void)
93 {
94 	write_seqlock(&mount_lock);
95 }
96 
97 static inline void unlock_mount_hash(void)
98 {
99 	write_sequnlock(&mount_lock);
100 }
101 
102 struct proc_mounts {
103 	struct seq_file m;
104 	struct mnt_namespace *ns;
105 	struct path root;
106 	int (*show)(struct seq_file *, struct vfsmount *);
107 	void *cached_mount;
108 	u64 cached_event;
109 	loff_t cached_index;
110 };
111 
112 #define proc_mounts(p) (container_of((p), struct proc_mounts, m))
113 
114 extern const struct seq_operations mounts_op;
115