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 extern struct list_head notify_list; 9 10 struct mnt_namespace { 11 struct ns_common ns; 12 struct mount * root; 13 struct { 14 struct rb_root mounts; /* Protected by namespace_sem */ 15 struct rb_node *mnt_last_node; /* last (rightmost) mount in the rbtree */ 16 struct rb_node *mnt_first_node; /* first (leftmost) mount in the rbtree */ 17 }; 18 struct user_namespace *user_ns; 19 struct ucounts *ucounts; 20 u64 seq; /* Sequence number to prevent loops */ 21 union { 22 wait_queue_head_t poll; 23 struct rcu_head mnt_ns_rcu; 24 }; 25 u64 event; 26 #ifdef CONFIG_FSNOTIFY 27 __u32 n_fsnotify_mask; 28 struct fsnotify_mark_connector __rcu *n_fsnotify_marks; 29 #endif 30 unsigned int nr_mounts; /* # of mounts in the namespace */ 31 unsigned int pending_mounts; 32 struct rb_node mnt_ns_tree_node; /* node in the mnt_ns_tree */ 33 struct list_head mnt_ns_list; /* entry in the sequential list of mounts namespace */ 34 refcount_t passive; /* number references not pinning @mounts */ 35 } __randomize_layout; 36 37 struct mnt_pcp { 38 int mnt_count; 39 int mnt_writers; 40 }; 41 42 struct mountpoint { 43 struct hlist_node m_hash; 44 struct dentry *m_dentry; 45 struct hlist_head m_list; 46 int m_count; 47 }; 48 49 struct mount { 50 struct hlist_node mnt_hash; 51 struct mount *mnt_parent; 52 struct dentry *mnt_mountpoint; 53 struct vfsmount mnt; 54 union { 55 struct rb_node mnt_node; /* node in the ns->mounts rbtree */ 56 struct rcu_head mnt_rcu; 57 struct llist_node mnt_llist; 58 }; 59 #ifdef CONFIG_SMP 60 struct mnt_pcp __percpu *mnt_pcp; 61 #else 62 int mnt_count; 63 int mnt_writers; 64 #endif 65 struct list_head mnt_mounts; /* list of children, anchored here */ 66 struct list_head mnt_child; /* and going through their mnt_child */ 67 struct list_head mnt_instance; /* mount instance on sb->s_mounts */ 68 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 69 struct list_head mnt_list; 70 struct list_head mnt_expire; /* link in fs-specific expiry list */ 71 struct list_head mnt_share; /* circular list of shared mounts */ 72 struct list_head mnt_slave_list;/* list of slave mounts */ 73 struct list_head mnt_slave; /* slave list entry */ 74 struct mount *mnt_master; /* slave is on master->mnt_slave_list */ 75 struct mnt_namespace *mnt_ns; /* containing namespace */ 76 struct mountpoint *mnt_mp; /* where is it mounted */ 77 union { 78 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ 79 struct hlist_node mnt_umount; 80 }; 81 struct list_head mnt_umounting; /* list entry for umount propagation */ 82 #ifdef CONFIG_FSNOTIFY 83 struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks; 84 __u32 mnt_fsnotify_mask; 85 struct list_head to_notify; /* need to queue notification */ 86 struct mnt_namespace *prev_ns; /* previous namespace (NULL if none) */ 87 #endif 88 int mnt_id; /* mount identifier, reused */ 89 u64 mnt_id_unique; /* mount ID unique until reboot */ 90 int mnt_group_id; /* peer group identifier */ 91 int mnt_expiry_mark; /* true if marked for expiry */ 92 struct hlist_head mnt_pins; 93 struct hlist_head mnt_stuck_children; 94 } __randomize_layout; 95 96 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */ 97 98 static inline struct mount *real_mount(struct vfsmount *mnt) 99 { 100 return container_of(mnt, struct mount, mnt); 101 } 102 103 static inline int mnt_has_parent(struct mount *mnt) 104 { 105 return mnt != mnt->mnt_parent; 106 } 107 108 static inline int is_mounted(struct vfsmount *mnt) 109 { 110 /* neither detached nor internal? */ 111 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns); 112 } 113 114 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); 115 116 extern int __legitimize_mnt(struct vfsmount *, unsigned); 117 118 static inline bool __path_is_mountpoint(const struct path *path) 119 { 120 struct mount *m = __lookup_mnt(path->mnt, path->dentry); 121 return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT)); 122 } 123 124 extern void __detach_mounts(struct dentry *dentry); 125 126 static inline void detach_mounts(struct dentry *dentry) 127 { 128 if (!d_mountpoint(dentry)) 129 return; 130 __detach_mounts(dentry); 131 } 132 133 static inline void get_mnt_ns(struct mnt_namespace *ns) 134 { 135 refcount_inc(&ns->ns.count); 136 } 137 138 extern seqlock_t mount_lock; 139 140 struct proc_mounts { 141 struct mnt_namespace *ns; 142 struct path root; 143 int (*show)(struct seq_file *, struct vfsmount *); 144 }; 145 146 extern const struct seq_operations mounts_op; 147 148 extern bool __is_local_mountpoint(struct dentry *dentry); 149 static inline bool is_local_mountpoint(struct dentry *dentry) 150 { 151 if (!d_mountpoint(dentry)) 152 return false; 153 154 return __is_local_mountpoint(dentry); 155 } 156 157 static inline bool is_anon_ns(struct mnt_namespace *ns) 158 { 159 return ns->seq == 0; 160 } 161 162 static inline bool mnt_ns_attached(const struct mount *mnt) 163 { 164 return !RB_EMPTY_NODE(&mnt->mnt_node); 165 } 166 167 static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list) 168 { 169 struct mnt_namespace *ns = mnt->mnt_ns; 170 WARN_ON(!mnt_ns_attached(mnt)); 171 if (ns->mnt_last_node == &mnt->mnt_node) 172 ns->mnt_last_node = rb_prev(&mnt->mnt_node); 173 if (ns->mnt_first_node == &mnt->mnt_node) 174 ns->mnt_first_node = rb_next(&mnt->mnt_node); 175 rb_erase(&mnt->mnt_node, &ns->mounts); 176 RB_CLEAR_NODE(&mnt->mnt_node); 177 list_add_tail(&mnt->mnt_list, dt_list); 178 } 179 180 bool has_locked_children(struct mount *mnt, struct dentry *dentry); 181 struct mnt_namespace *get_sequential_mnt_ns(struct mnt_namespace *mnt_ns, 182 bool previous); 183 184 static inline struct mnt_namespace *to_mnt_ns(struct ns_common *ns) 185 { 186 return container_of(ns, struct mnt_namespace, ns); 187 } 188 189 #ifdef CONFIG_FSNOTIFY 190 static inline void mnt_notify_add(struct mount *m) 191 { 192 /* Optimize the case where there are no watches */ 193 if ((m->mnt_ns && m->mnt_ns->n_fsnotify_marks) || 194 (m->prev_ns && m->prev_ns->n_fsnotify_marks)) 195 list_add_tail(&m->to_notify, ¬ify_list); 196 else 197 m->prev_ns = m->mnt_ns; 198 } 199 #else 200 static inline void mnt_notify_add(struct mount *m) 201 { 202 } 203 #endif 204 205 struct mnt_namespace *mnt_ns_from_dentry(struct dentry *dentry); 206