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 wait_queue_head_t poll; 16 u64 event; 17 unsigned int nr_mounts; /* # of mounts in the namespace */ 18 unsigned int pending_mounts; 19 } __randomize_layout; 20 21 struct mnt_pcp { 22 int mnt_count; 23 int mnt_writers; 24 }; 25 26 struct mountpoint { 27 struct hlist_node m_hash; 28 struct dentry *m_dentry; 29 struct hlist_head m_list; 30 int m_count; 31 }; 32 33 struct mount { 34 struct hlist_node mnt_hash; 35 struct mount *mnt_parent; 36 struct dentry *mnt_mountpoint; 37 struct vfsmount mnt; 38 union { 39 struct rcu_head mnt_rcu; 40 struct llist_node mnt_llist; 41 }; 42 #ifdef CONFIG_SMP 43 struct mnt_pcp __percpu *mnt_pcp; 44 #else 45 int mnt_count; 46 int mnt_writers; 47 #endif 48 struct list_head mnt_mounts; /* list of children, anchored here */ 49 struct list_head mnt_child; /* and going through their mnt_child */ 50 struct list_head mnt_instance; /* mount instance on sb->s_mounts */ 51 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 52 union { 53 struct rb_node mnt_node; /* Under ns->mounts */ 54 struct list_head mnt_list; 55 }; 56 struct list_head mnt_expire; /* link in fs-specific expiry list */ 57 struct list_head mnt_share; /* circular list of shared mounts */ 58 struct list_head mnt_slave_list;/* list of slave mounts */ 59 struct list_head mnt_slave; /* slave list entry */ 60 struct mount *mnt_master; /* slave is on master->mnt_slave_list */ 61 struct mnt_namespace *mnt_ns; /* containing namespace */ 62 struct mountpoint *mnt_mp; /* where is it mounted */ 63 union { 64 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ 65 struct hlist_node mnt_umount; 66 }; 67 struct list_head mnt_umounting; /* list entry for umount propagation */ 68 #ifdef CONFIG_FSNOTIFY 69 struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks; 70 __u32 mnt_fsnotify_mask; 71 #endif 72 int mnt_id; /* mount identifier, reused */ 73 u64 mnt_id_unique; /* mount ID unique until reboot */ 74 int mnt_group_id; /* peer group identifier */ 75 int mnt_expiry_mark; /* true if marked for expiry */ 76 struct hlist_head mnt_pins; 77 struct hlist_head mnt_stuck_children; 78 } __randomize_layout; 79 80 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */ 81 82 static inline struct mount *real_mount(struct vfsmount *mnt) 83 { 84 return container_of(mnt, struct mount, mnt); 85 } 86 87 static inline int mnt_has_parent(struct mount *mnt) 88 { 89 return mnt != mnt->mnt_parent; 90 } 91 92 static inline int is_mounted(struct vfsmount *mnt) 93 { 94 /* neither detached nor internal? */ 95 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns); 96 } 97 98 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); 99 100 extern int __legitimize_mnt(struct vfsmount *, unsigned); 101 102 static inline bool __path_is_mountpoint(const struct path *path) 103 { 104 struct mount *m = __lookup_mnt(path->mnt, path->dentry); 105 return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT)); 106 } 107 108 extern void __detach_mounts(struct dentry *dentry); 109 110 static inline void detach_mounts(struct dentry *dentry) 111 { 112 if (!d_mountpoint(dentry)) 113 return; 114 __detach_mounts(dentry); 115 } 116 117 static inline void get_mnt_ns(struct mnt_namespace *ns) 118 { 119 refcount_inc(&ns->ns.count); 120 } 121 122 extern seqlock_t mount_lock; 123 124 struct proc_mounts { 125 struct mnt_namespace *ns; 126 struct path root; 127 int (*show)(struct seq_file *, struct vfsmount *); 128 }; 129 130 extern const struct seq_operations mounts_op; 131 132 extern bool __is_local_mountpoint(struct dentry *dentry); 133 static inline bool is_local_mountpoint(struct dentry *dentry) 134 { 135 if (!d_mountpoint(dentry)) 136 return false; 137 138 return __is_local_mountpoint(dentry); 139 } 140 141 static inline bool is_anon_ns(struct mnt_namespace *ns) 142 { 143 return ns->seq == 0; 144 } 145 146 static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list) 147 { 148 WARN_ON(!(mnt->mnt.mnt_flags & MNT_ONRB)); 149 mnt->mnt.mnt_flags &= ~MNT_ONRB; 150 rb_erase(&mnt->mnt_node, &mnt->mnt_ns->mounts); 151 list_add_tail(&mnt->mnt_list, dt_list); 152 } 153 154 extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor); 155