| 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 | |
| 84 | static inline struct mount *real_mount(struct vfsmount *mnt) |
| 85 | { |
| 86 | return container_of(mnt, struct mount, mnt); |
| 87 | } |
| 88 | |
| 89 | static inline int mnt_has_parent(struct mount *mnt) |
| 90 | { |
| 91 | return mnt != mnt->mnt_parent; |
| 92 | } |
| 93 | |
| 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 | |
| 104 | static 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 | |
| 110 | extern void __detach_mounts(struct dentry *dentry); |
| 111 | |
| 112 | static inline void detach_mounts(struct dentry *dentry) |
| 113 | { |
| 114 | if (!d_mountpoint(dentry)) |
| 115 | return; |
| 116 | __detach_mounts(dentry); |
| 117 | } |
| 118 | |
| 119 | static inline void get_mnt_ns(struct mnt_namespace *ns) |
| 120 | { |
| 121 | refcount_inc(&ns->ns.count); |
| 122 | } |
| 123 | |
| 124 | extern seqlock_t mount_lock; |
| 125 | |
| 126 | struct proc_mounts { |
| 127 | struct mnt_namespace *ns; |
| 128 | struct path root; |
| 129 | int (*show)(struct seq_file *, struct vfsmount *); |
| 130 | struct mount cursor; |
| 131 | }; |
| 132 | |
| 133 | extern const struct seq_operations mounts_op; |
| 134 | |
| 135 | extern bool __is_local_mountpoint(struct dentry *dentry); |
| 136 | static inline bool is_local_mountpoint(struct dentry *dentry) |
| 137 | { |
| 138 | if (!d_mountpoint(dentry)) |
| 139 | return false; |
| 140 | |
| 141 | return __is_local_mountpoint(dentry); |
| 142 | } |
| 143 | |
| 144 | static inline bool is_anon_ns(struct mnt_namespace *ns) |
| 145 | { |
| 146 | return ns->seq == 0; |
| 147 | } |
| 148 | |
| 149 | extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor); |