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