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 typedef __u32 __bitwise mntns_flags_t; 11 12 #define MNTNS_PROPAGATING ((__force mntns_flags_t)(1 << 0)) 13 14 struct mnt_namespace { 15 struct ns_common ns; 16 struct mount * root; 17 struct { 18 struct rb_root mounts; /* Protected by namespace_sem */ 19 struct rb_node *mnt_last_node; /* last (rightmost) mount in the rbtree */ 20 struct rb_node *mnt_first_node; /* first (leftmost) mount in the rbtree */ 21 }; 22 struct user_namespace *user_ns; 23 struct ucounts *ucounts; 24 u64 seq; /* Sequence number to prevent loops */ 25 union { 26 wait_queue_head_t poll; 27 struct rcu_head mnt_ns_rcu; 28 }; 29 u64 seq_origin; /* Sequence number of origin mount namespace */ 30 u64 event; 31 #ifdef CONFIG_FSNOTIFY 32 __u32 n_fsnotify_mask; 33 struct fsnotify_mark_connector __rcu *n_fsnotify_marks; 34 #endif 35 unsigned int nr_mounts; /* # of mounts in the namespace */ 36 unsigned int pending_mounts; 37 struct rb_node mnt_ns_tree_node; /* node in the mnt_ns_tree */ 38 struct list_head mnt_ns_list; /* entry in the sequential list of mounts namespace */ 39 refcount_t passive; /* number references not pinning @mounts */ 40 mntns_flags_t mntns_flags; 41 } __randomize_layout; 42 43 struct mnt_pcp { 44 int mnt_count; 45 int mnt_writers; 46 }; 47 48 struct mountpoint { 49 struct hlist_node m_hash; 50 struct dentry *m_dentry; 51 struct hlist_head m_list; 52 int m_count; 53 }; 54 55 struct mount { 56 struct hlist_node mnt_hash; 57 struct mount *mnt_parent; 58 struct dentry *mnt_mountpoint; 59 struct vfsmount mnt; 60 union { 61 struct rb_node mnt_node; /* node in the ns->mounts rbtree */ 62 struct rcu_head mnt_rcu; 63 struct llist_node mnt_llist; 64 }; 65 #ifdef CONFIG_SMP 66 struct mnt_pcp __percpu *mnt_pcp; 67 #else 68 int mnt_count; 69 int mnt_writers; 70 #endif 71 struct list_head mnt_mounts; /* list of children, anchored here */ 72 struct list_head mnt_child; /* and going through their mnt_child */ 73 struct list_head mnt_instance; /* mount instance on sb->s_mounts */ 74 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 75 struct list_head mnt_list; 76 struct list_head mnt_expire; /* link in fs-specific expiry list */ 77 struct list_head mnt_share; /* circular list of shared mounts */ 78 struct list_head mnt_slave_list;/* list of slave mounts */ 79 struct list_head mnt_slave; /* slave list entry */ 80 struct mount *mnt_master; /* slave is on master->mnt_slave_list */ 81 struct mnt_namespace *mnt_ns; /* containing namespace */ 82 struct mountpoint *mnt_mp; /* where is it mounted */ 83 union { 84 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ 85 struct hlist_node mnt_umount; 86 }; 87 struct list_head mnt_umounting; /* list entry for umount propagation */ 88 #ifdef CONFIG_FSNOTIFY 89 struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks; 90 __u32 mnt_fsnotify_mask; 91 struct list_head to_notify; /* need to queue notification */ 92 struct mnt_namespace *prev_ns; /* previous namespace (NULL if none) */ 93 #endif 94 int mnt_id; /* mount identifier, reused */ 95 u64 mnt_id_unique; /* mount ID unique until reboot */ 96 int mnt_group_id; /* peer group identifier */ 97 int mnt_expiry_mark; /* true if marked for expiry */ 98 struct hlist_head mnt_pins; 99 struct hlist_head mnt_stuck_children; 100 } __randomize_layout; 101 102 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */ 103 104 static inline struct mount *real_mount(struct vfsmount *mnt) 105 { 106 return container_of(mnt, struct mount, mnt); 107 } 108 109 static inline int mnt_has_parent(struct mount *mnt) 110 { 111 return mnt != mnt->mnt_parent; 112 } 113 114 static inline int is_mounted(struct vfsmount *mnt) 115 { 116 /* neither detached nor internal? */ 117 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns); 118 } 119 120 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); 121 122 extern int __legitimize_mnt(struct vfsmount *, unsigned); 123 124 static inline bool __path_is_mountpoint(const struct path *path) 125 { 126 struct mount *m = __lookup_mnt(path->mnt, path->dentry); 127 return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT)); 128 } 129 130 extern void __detach_mounts(struct dentry *dentry); 131 132 static inline void detach_mounts(struct dentry *dentry) 133 { 134 if (!d_mountpoint(dentry)) 135 return; 136 __detach_mounts(dentry); 137 } 138 139 static inline void get_mnt_ns(struct mnt_namespace *ns) 140 { 141 refcount_inc(&ns->ns.count); 142 } 143 144 extern seqlock_t mount_lock; 145 146 struct proc_mounts { 147 struct mnt_namespace *ns; 148 struct path root; 149 int (*show)(struct seq_file *, struct vfsmount *); 150 }; 151 152 extern const struct seq_operations mounts_op; 153 154 extern bool __is_local_mountpoint(struct dentry *dentry); 155 static inline bool is_local_mountpoint(struct dentry *dentry) 156 { 157 if (!d_mountpoint(dentry)) 158 return false; 159 160 return __is_local_mountpoint(dentry); 161 } 162 163 static inline bool is_anon_ns(struct mnt_namespace *ns) 164 { 165 return ns->seq == 0; 166 } 167 168 static inline bool mnt_ns_attached(const struct mount *mnt) 169 { 170 return !RB_EMPTY_NODE(&mnt->mnt_node); 171 } 172 173 static inline bool mnt_ns_empty(const struct mnt_namespace *ns) 174 { 175 return RB_EMPTY_ROOT(&ns->mounts); 176 } 177 178 static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list) 179 { 180 struct mnt_namespace *ns = mnt->mnt_ns; 181 WARN_ON(!mnt_ns_attached(mnt)); 182 if (ns->mnt_last_node == &mnt->mnt_node) 183 ns->mnt_last_node = rb_prev(&mnt->mnt_node); 184 if (ns->mnt_first_node == &mnt->mnt_node) 185 ns->mnt_first_node = rb_next(&mnt->mnt_node); 186 rb_erase(&mnt->mnt_node, &ns->mounts); 187 RB_CLEAR_NODE(&mnt->mnt_node); 188 list_add_tail(&mnt->mnt_list, dt_list); 189 } 190 191 bool has_locked_children(struct mount *mnt, struct dentry *dentry); 192 struct mnt_namespace *get_sequential_mnt_ns(struct mnt_namespace *mnt_ns, 193 bool previous); 194 195 static inline struct mnt_namespace *to_mnt_ns(struct ns_common *ns) 196 { 197 return container_of(ns, struct mnt_namespace, ns); 198 } 199 200 #ifdef CONFIG_FSNOTIFY 201 static inline void mnt_notify_add(struct mount *m) 202 { 203 /* Optimize the case where there are no watches */ 204 if ((m->mnt_ns && m->mnt_ns->n_fsnotify_marks) || 205 (m->prev_ns && m->prev_ns->n_fsnotify_marks)) 206 list_add_tail(&m->to_notify, ¬ify_list); 207 else 208 m->prev_ns = m->mnt_ns; 209 } 210 #else 211 static inline void mnt_notify_add(struct mount *m) 212 { 213 } 214 #endif 215 216 struct mnt_namespace *mnt_ns_from_dentry(struct dentry *dentry); 217