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 seq_origin; /* Sequence number of origin mount namespace */ 26 u64 event; 27 #ifdef CONFIG_FSNOTIFY 28 __u32 n_fsnotify_mask; 29 struct fsnotify_mark_connector __rcu *n_fsnotify_marks; 30 #endif 31 unsigned int nr_mounts; /* # of mounts in the namespace */ 32 unsigned int pending_mounts; 33 struct rb_node mnt_ns_tree_node; /* node in the mnt_ns_tree */ 34 struct list_head mnt_ns_list; /* entry in the sequential list of mounts namespace */ 35 refcount_t passive; /* number references not pinning @mounts */ 36 } __randomize_layout; 37 38 struct mnt_pcp { 39 int mnt_count; 40 int mnt_writers; 41 }; 42 43 struct mountpoint { 44 struct hlist_node m_hash; 45 struct dentry *m_dentry; 46 struct hlist_head m_list; 47 int m_count; 48 }; 49 50 struct mount { 51 struct hlist_node mnt_hash; 52 struct mount *mnt_parent; 53 struct dentry *mnt_mountpoint; 54 struct vfsmount mnt; 55 union { 56 struct rb_node mnt_node; /* node in the ns->mounts rbtree */ 57 struct rcu_head mnt_rcu; 58 struct llist_node mnt_llist; 59 }; 60 #ifdef CONFIG_SMP 61 struct mnt_pcp __percpu *mnt_pcp; 62 #else 63 int mnt_count; 64 int mnt_writers; 65 #endif 66 struct list_head mnt_mounts; /* list of children, anchored here */ 67 struct list_head mnt_child; /* and going through their mnt_child */ 68 struct list_head mnt_instance; /* mount instance on sb->s_mounts */ 69 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 70 struct list_head mnt_list; 71 struct list_head mnt_expire; /* link in fs-specific expiry list */ 72 struct list_head mnt_share; /* circular list of shared mounts */ 73 struct list_head mnt_slave_list;/* list of slave mounts */ 74 struct list_head mnt_slave; /* slave list entry */ 75 struct mount *mnt_master; /* slave is on master->mnt_slave_list */ 76 struct mnt_namespace *mnt_ns; /* containing namespace */ 77 struct mountpoint *mnt_mp; /* where is it mounted */ 78 union { 79 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ 80 struct hlist_node mnt_umount; 81 }; 82 struct list_head mnt_umounting; /* list entry for umount propagation */ 83 #ifdef CONFIG_FSNOTIFY 84 struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks; 85 __u32 mnt_fsnotify_mask; 86 struct list_head to_notify; /* need to queue notification */ 87 struct mnt_namespace *prev_ns; /* previous namespace (NULL if none) */ 88 #endif 89 int mnt_id; /* mount identifier, reused */ 90 u64 mnt_id_unique; /* mount ID unique until reboot */ 91 int mnt_group_id; /* peer group identifier */ 92 int mnt_expiry_mark; /* true if marked for expiry */ 93 struct hlist_head mnt_pins; 94 struct hlist_head mnt_stuck_children; 95 } __randomize_layout; 96 97 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */ 98 99 static inline struct mount *real_mount(struct vfsmount *mnt) 100 { 101 return container_of(mnt, struct mount, mnt); 102 } 103 104 static inline int mnt_has_parent(struct mount *mnt) 105 { 106 return mnt != mnt->mnt_parent; 107 } 108 109 static inline int is_mounted(struct vfsmount *mnt) 110 { 111 /* neither detached nor internal? */ 112 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns); 113 } 114 115 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); 116 117 extern int __legitimize_mnt(struct vfsmount *, unsigned); 118 119 static inline bool __path_is_mountpoint(const struct path *path) 120 { 121 struct mount *m = __lookup_mnt(path->mnt, path->dentry); 122 return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT)); 123 } 124 125 extern void __detach_mounts(struct dentry *dentry); 126 127 static inline void detach_mounts(struct dentry *dentry) 128 { 129 if (!d_mountpoint(dentry)) 130 return; 131 __detach_mounts(dentry); 132 } 133 134 static inline void get_mnt_ns(struct mnt_namespace *ns) 135 { 136 refcount_inc(&ns->ns.count); 137 } 138 139 extern seqlock_t mount_lock; 140 141 struct proc_mounts { 142 struct mnt_namespace *ns; 143 struct path root; 144 int (*show)(struct seq_file *, struct vfsmount *); 145 }; 146 147 extern const struct seq_operations mounts_op; 148 149 extern bool __is_local_mountpoint(struct dentry *dentry); 150 static inline bool is_local_mountpoint(struct dentry *dentry) 151 { 152 if (!d_mountpoint(dentry)) 153 return false; 154 155 return __is_local_mountpoint(dentry); 156 } 157 158 static inline bool is_anon_ns(struct mnt_namespace *ns) 159 { 160 return ns->seq == 0; 161 } 162 163 static inline bool mnt_ns_attached(const struct mount *mnt) 164 { 165 return !RB_EMPTY_NODE(&mnt->mnt_node); 166 } 167 168 static inline bool mnt_ns_empty(const struct mnt_namespace *ns) 169 { 170 return RB_EMPTY_ROOT(&ns->mounts); 171 } 172 173 static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list) 174 { 175 struct mnt_namespace *ns = mnt->mnt_ns; 176 WARN_ON(!mnt_ns_attached(mnt)); 177 if (ns->mnt_last_node == &mnt->mnt_node) 178 ns->mnt_last_node = rb_prev(&mnt->mnt_node); 179 if (ns->mnt_first_node == &mnt->mnt_node) 180 ns->mnt_first_node = rb_next(&mnt->mnt_node); 181 rb_erase(&mnt->mnt_node, &ns->mounts); 182 RB_CLEAR_NODE(&mnt->mnt_node); 183 list_add_tail(&mnt->mnt_list, dt_list); 184 } 185 186 bool has_locked_children(struct mount *mnt, struct dentry *dentry); 187 struct mnt_namespace *get_sequential_mnt_ns(struct mnt_namespace *mnt_ns, 188 bool previous); 189 190 static inline struct mnt_namespace *to_mnt_ns(struct ns_common *ns) 191 { 192 return container_of(ns, struct mnt_namespace, ns); 193 } 194 195 #ifdef CONFIG_FSNOTIFY 196 static inline void mnt_notify_add(struct mount *m) 197 { 198 /* Optimize the case where there are no watches */ 199 if ((m->mnt_ns && m->mnt_ns->n_fsnotify_marks) || 200 (m->prev_ns && m->prev_ns->n_fsnotify_marks)) 201 list_add_tail(&m->to_notify, ¬ify_list); 202 else 203 m->prev_ns = m->mnt_ns; 204 } 205 #else 206 static inline void mnt_notify_add(struct mount *m) 207 { 208 } 209 #endif 210 211 struct mnt_namespace *mnt_ns_from_dentry(struct dentry *dentry); 212