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 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 23 struct mnt_pcp { 24 int mnt_count; 25 int mnt_writers; 26 }; 27 28 struct mountpoint { 29 struct hlist_node m_hash; 30 struct dentry *m_dentry; 31 struct hlist_head m_list; 32 int m_count; 33 }; 34 35 struct 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 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 }; 131 132 extern const struct seq_operations mounts_op; 133 134 extern bool __is_local_mountpoint(struct dentry *dentry); 135 static 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 } 142 143 static inline bool is_anon_ns(struct mnt_namespace *ns) 144 { 145 return ns->seq == 0; 146 } 147 148 static 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 } 155 156 bool has_locked_children(struct mount *mnt, struct dentry *dentry); 157 struct mnt_namespace *__lookup_next_mnt_ns(struct mnt_namespace *mnt_ns, bool previous); 158 static inline struct mnt_namespace *lookup_next_mnt_ns(struct mnt_namespace *mntns) 159 { 160 return __lookup_next_mnt_ns(mntns, false); 161 } 162 static inline struct mnt_namespace *lookup_prev_mnt_ns(struct mnt_namespace *mntns) 163 { 164 return __lookup_next_mnt_ns(mntns, true); 165 } 166 static inline struct mnt_namespace *to_mnt_ns(struct ns_common *ns) 167 { 168 return container_of(ns, struct mnt_namespace, ns); 169 } 170