summaryrefslogtreecommitdiff
path: root/fs/mount.h
blob: 6250de544760e1ed28bd1e91df35f45ad29d9e8c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/mount.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/ns_common.h>
#include <linux/fs_pin.h>

struct mnt_namespace {
	atomic_t		count;
	struct ns_common	ns;
	struct mount *	root;
	struct list_head	list;
	struct user_namespace	*user_ns;
	struct ucounts		*ucounts;
	u64			seq;	/* Sequence number to prevent loops */
	wait_queue_head_t poll;
	u64 event;
	unsigned int		mounts; /* # of mounts in the namespace */
	unsigned int		pending_mounts;
} __randomize_layout;

struct mnt_pcp {
	int mnt_count;
	int mnt_writers;
};

struct mountpoint {
	struct hlist_node m_hash;
	struct dentry *m_dentry;
	struct hlist_head m_list;
	int m_count;
};

struct mount {
	struct hlist_node mnt_hash;
	struct mount *mnt_parent;
	struct dentry *mnt_mountpoint;
	struct vfsmount mnt;
	union {
		struct rcu_head mnt_rcu;
		struct llist_node mnt_llist;
	};
#ifdef CONFIG_SMP
	struct mnt_pcp __percpu *mnt_pcp;
#else
	int mnt_count;
	int mnt_writers;
#endif
	struct list_head mnt_mounts;	/* list of children, anchored here */
	struct list_head mnt_child;	/* and going through their mnt_child */
	struct list_head mnt_instance;	/* mount instance on sb->s_mounts */
	const char *mnt_devname;	/* Name of device e.g. /dev/dsk/hda1 */
	struct list_head mnt_list;
	struct list_head mnt_expire;	/* link in fs-specific expiry list */
	struct list_head mnt_share;	/* circular list of shared mounts */
	struct list_head mnt_slave_list;/* list of slave mounts */
	struct list_head mnt_slave;	/* slave list entry */
	struct mount *mnt_master;	/* slave is on master->mnt_slave_list */
	struct mnt_namespace *mnt_ns;	/* containing namespace */
	struct mountpoint *mnt_mp;	/* where is it mounted */
	struct hlist_node mnt_mp_list;	/* list mounts with the same mountpoint */
	struct list_head mnt_umounting; /* list entry for umount propagation */
#ifdef CONFIG_FSNOTIFY
	struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks;
	__u32 mnt_fsnotify_mask;
#endif
	int mnt_id;			/* mount identifier */
	int mnt_group_id;		/* peer group identifier */
	int mnt_expiry_mark;		/* true if marked for expiry */
	struct hlist_head mnt_pins;
	struct fs_pin mnt_umount;
	struct dentry *mnt_ex_mountpoint;
} __randomize_layout;

#define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */

static inline struct mount *real_mount(struct vfsmount *mnt)
{
	return container_of(mnt, struct mount, mnt);
}

static inline int mnt_has_parent(struct mount *mnt)
{
	return mnt != mnt->mnt_parent;
}

static inline int is_mounted(struct vfsmount *mnt)
{
	/* neither detached nor internal? */
	return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
}

extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);

extern int __legitimize_mnt(struct vfsmount *, unsigned);
extern bool legitimize_mnt(struct vfsmount *, unsigned);

static inline bool __path_is_mountpoint(const struct path *path)
{
	struct mount *m = __lookup_mnt(path->mnt, path->dentry);
	return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
}

extern void __detach_mounts(struct dentry *dentry);

static inline void detach_mounts(struct dentry *dentry)
{
	if (!d_mountpoint(dentry))
		return;
	__detach_mounts(dentry);
}

static inline void get_mnt_ns(struct mnt_namespace *ns)
{
	atomic_inc(&ns->count);
}

extern seqlock_t mount_lock;

static inline void lock_mount_hash(void)
{
	write_seqlock(&mount_lock);
}

static inline void unlock_mount_hash(void)
{
	write_sequnlock(&mount_lock);
}

struct proc_mounts {
	struct mnt_namespace *ns;
	struct path root;
	int (*show)(struct seq_file *, struct vfsmount *);
	void *cached_mount;
	u64 cached_event;
	loff_t cached_index;
};

extern const struct seq_operations mounts_op;

extern bool __is_local_mountpoint(struct dentry *dentry);
static inline bool is_local_mountpoint(struct dentry *dentry)
{
	if (!d_mountpoint(dentry))
		return false;

	return __is_local_mountpoint(dentry);
}

static inline bool is_anon_ns(struct mnt_namespace *ns)
{
	return ns->seq == 0;
}