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 { 12 struct rb_root mounts; /* Protected by namespace_sem */ 13 struct rb_node *mnt_last_node; /* last (rightmost) mount in the rbtree */ 14 struct rb_node *mnt_first_node; /* first (leftmost) mount in the rbtree */ 15 }; 16 struct user_namespace *user_ns; 17 struct ucounts *ucounts; 18 u64 seq; /* Sequence number to prevent loops */ 19 union { 20 wait_queue_head_t poll; 21 struct rcu_head mnt_ns_rcu; 22 }; 23 u64 event; 24 unsigned int nr_mounts; /* # of mounts in the namespace */ 25 unsigned int pending_mounts; 26 struct rb_node mnt_ns_tree_node; /* node in the mnt_ns_tree */ 27 struct list_head mnt_ns_list; /* entry in the sequential list of mounts namespace */ 28 refcount_t passive; /* number references not pinning @mounts */ 29 } __randomize_layout; 30 31 struct mnt_pcp { 32 int mnt_count; 33 int mnt_writers; 34 }; 35 36 struct mountpoint { 37 struct hlist_node m_hash; 38 struct dentry *m_dentry; 39 struct hlist_head m_list; 40 int m_count; 41 }; 42 43 struct mount { 44 struct hlist_node mnt_hash; 45 struct mount *mnt_parent; 46 struct dentry *mnt_mountpoint; 47 struct vfsmount mnt; 48 union { 49 struct rb_node mnt_node; /* node in the ns->mounts rbtree */ 50 struct rcu_head mnt_rcu; 51 struct llist_node mnt_llist; 52 }; 53 #ifdef CONFIG_SMP 54 struct mnt_pcp __percpu *mnt_pcp; 55 #else 56 int mnt_count; 57 int mnt_writers; 58 #endif 59 struct list_head mnt_mounts; /* list of children, anchored here */ 60 struct list_head mnt_child; /* and going through their mnt_child */ 61 struct list_head mnt_instance; /* mount instance on sb->s_mounts */ 62 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 63 struct list_head mnt_list; 64 struct list_head mnt_expire; /* link in fs-specific expiry list */ 65 struct list_head mnt_share; /* circular list of shared mounts */ 66 struct list_head mnt_slave_list;/* list of slave mounts */ 67 struct list_head mnt_slave; /* slave list entry */ 68 struct mount *mnt_master; /* slave is on master->mnt_slave_list */ 69 struct mnt_namespace *mnt_ns; /* containing namespace */ 70 struct mountpoint *mnt_mp; /* where is it mounted */ 71 union { 72 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ 73 struct hlist_node mnt_umount; 74 }; 75 struct list_head mnt_umounting; /* list entry for umount propagation */ 76 #ifdef CONFIG_FSNOTIFY 77 struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks; 78 __u32 mnt_fsnotify_mask; 79 #endif 80 int mnt_id; /* mount identifier, reused */ 81 u64 mnt_id_unique; /* mount ID unique until reboot */ 82 int mnt_group_id; /* peer group identifier */ 83 int mnt_expiry_mark; /* true if marked for expiry */ 84 struct hlist_head mnt_pins; 85 struct hlist_head mnt_stuck_children; 86 } __randomize_layout; 87 88 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */ 89 90 static inline struct mount *real_mount(struct vfsmount *mnt) 91 { 92 return container_of(mnt, struct mount, mnt); 93 } 94 95 static inline int mnt_has_parent(struct mount *mnt) 96 { 97 return mnt != mnt->mnt_parent; 98 } 99 100 static inline int is_mounted(struct vfsmount *mnt) 101 { 102 /* neither detached nor internal? */ 103 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns); 104 } 105 106 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); 107 108 extern int __legitimize_mnt(struct vfsmount *, unsigned); 109 110 static inline bool __path_is_mountpoint(const struct path *path) 111 { 112 struct mount *m = __lookup_mnt(path->mnt, path->dentry); 113 return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT)); 114 } 115 116 extern void __detach_mounts(struct dentry *dentry); 117 118 static inline void detach_mounts(struct dentry *dentry) 119 { 120 if (!d_mountpoint(dentry)) 121 return; 122 __detach_mounts(dentry); 123 } 124 125 static inline void get_mnt_ns(struct mnt_namespace *ns) 126 { 127 refcount_inc(&ns->ns.count); 128 } 129 130 extern seqlock_t mount_lock; 131 132 struct proc_mounts { 133 struct mnt_namespace *ns; 134 struct path root; 135 int (*show)(struct seq_file *, struct vfsmount *); 136 }; 137 138 extern const struct seq_operations mounts_op; 139 140 extern bool __is_local_mountpoint(struct dentry *dentry); 141 static inline bool is_local_mountpoint(struct dentry *dentry) 142 { 143 if (!d_mountpoint(dentry)) 144 return false; 145 146 return __is_local_mountpoint(dentry); 147 } 148 149 static inline bool is_anon_ns(struct mnt_namespace *ns) 150 { 151 return ns->seq == 0; 152 } 153 154 static inline bool mnt_ns_attached(const struct mount *mnt) 155 { 156 return !RB_EMPTY_NODE(&mnt->mnt_node); 157 } 158 159 static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list) 160 { 161 struct mnt_namespace *ns = mnt->mnt_ns; 162 WARN_ON(!mnt_ns_attached(mnt)); 163 if (ns->mnt_last_node == &mnt->mnt_node) 164 ns->mnt_last_node = rb_prev(&mnt->mnt_node); 165 if (ns->mnt_first_node == &mnt->mnt_node) 166 ns->mnt_first_node = rb_next(&mnt->mnt_node); 167 rb_erase(&mnt->mnt_node, &ns->mounts); 168 RB_CLEAR_NODE(&mnt->mnt_node); 169 list_add_tail(&mnt->mnt_list, dt_list); 170 } 171 172 bool has_locked_children(struct mount *mnt, struct dentry *dentry); 173 struct mnt_namespace *get_sequential_mnt_ns(struct mnt_namespace *mnt_ns, 174 bool previous); 175 176 static inline struct mnt_namespace *to_mnt_ns(struct ns_common *ns) 177 { 178 return container_of(ns, struct mnt_namespace, ns); 179 } 180