Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
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
8struct 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
23struct mnt_pcp {
24 int mnt_count;
25 int mnt_writers;
26};
27
28struct mountpoint {
29 struct hlist_node m_hash;
30 struct dentry *m_dentry;
31 struct hlist_head m_list;
32 int m_count;
33};
34
35struct 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
84static inline struct mount *real_mount(struct vfsmount *mnt)
85{
86 return container_of(mnt, struct mount, mnt);
87}
88
89static inline int mnt_has_parent(struct mount *mnt)
90{
91 return mnt != mnt->mnt_parent;
92}
93
94static 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
100extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
101
102extern int __legitimize_mnt(struct vfsmount *, unsigned);
103
104static 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
110extern void __detach_mounts(struct dentry *dentry);
111
112static inline void detach_mounts(struct dentry *dentry)
113{
114 if (!d_mountpoint(dentry))
115 return;
116 __detach_mounts(dentry);
117}
118
119static inline void get_mnt_ns(struct mnt_namespace *ns)
120{
121 refcount_inc(&ns->ns.count);
122}
123
124extern seqlock_t mount_lock;
125
126struct proc_mounts {
127 struct mnt_namespace *ns;
128 struct path root;
129 int (*show)(struct seq_file *, struct vfsmount *);
130};
131
132extern const struct seq_operations mounts_op;
133
134extern bool __is_local_mountpoint(struct dentry *dentry);
135static 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
143static inline bool is_anon_ns(struct mnt_namespace *ns)
144{
145 return ns->seq == 0;
146}
147
148static 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
156bool has_locked_children(struct mount *mnt, struct dentry *dentry);
157struct mnt_namespace *__lookup_next_mnt_ns(struct mnt_namespace *mnt_ns, bool previous);
158static inline struct mnt_namespace *lookup_next_mnt_ns(struct mnt_namespace *mntns)
159{
160 return __lookup_next_mnt_ns(mntns, false);
161}
162static inline struct mnt_namespace *lookup_prev_mnt_ns(struct mnt_namespace *mntns)
163{
164 return __lookup_next_mnt_ns(mntns, true);
165}
166static inline struct mnt_namespace *to_mnt_ns(struct ns_common *ns)
167{
168 return container_of(ns, struct mnt_namespace, ns);
169}