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 /* 12 * Traversal and modification of .list is protected by either 13 * - taking namespace_sem for write, OR 14 * - taking namespace_sem for read AND taking .ns_lock. 15 */ 16 struct list_head list; 17 spinlock_t ns_lock; 18 struct user_namespace *user_ns; 19 struct ucounts *ucounts; 20 u64 seq; /* Sequence number to prevent loops */ 21 wait_queue_head_t poll; 22 u64 event; 23 unsigned int mounts; /* # of mounts in the namespace */ 24 unsigned int pending_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 rcu_head mnt_rcu; 46 struct llist_node mnt_llist; 47 }; 48 #ifdef CONFIG_SMP 49 struct mnt_pcp __percpu *mnt_pcp; 50 #else 51 int mnt_count; 52 int mnt_writers; 53 #endif 54 struct list_head mnt_mounts; /* list of children, anchored here */ 55 struct list_head mnt_child; /* and going through their mnt_child */ 56 struct list_head mnt_instance; /* mount instance on sb->s_mounts */ 57 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 58 struct list_head mnt_list; 59 struct list_head mnt_expire; /* link in fs-specific expiry list */ 60 struct list_head mnt_share; /* circular list of shared mounts */ 61 struct list_head mnt_slave_list;/* list of slave mounts */ 62 struct list_head mnt_slave; /* slave list entry */ 63 struct mount *mnt_master; /* slave is on master->mnt_slave_list */ 64 struct mnt_namespace *mnt_ns; /* containing namespace */ 65 struct mountpoint *mnt_mp; /* where is it mounted */ 66 union { 67 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ 68 struct hlist_node mnt_umount; 69 }; 70 struct list_head mnt_umounting; /* list entry for umount propagation */ 71 #ifdef CONFIG_FSNOTIFY 72 struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks; 73 __u32 mnt_fsnotify_mask; 74 #endif 75 int mnt_id; /* mount identifier */ 76 int mnt_group_id; /* peer group identifier */ 77 int mnt_expiry_mark; /* true if marked for expiry */ 78 struct hlist_head mnt_pins; 79 struct hlist_head mnt_stuck_children; 80 } __randomize_layout; 81 82 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */ 83 real_mount(struct vfsmount * mnt)84static inline struct mount *real_mount(struct vfsmount *mnt) 85 { 86 return container_of(mnt, struct mount, mnt); 87 } 88 mnt_has_parent(struct mount * mnt)89static inline int mnt_has_parent(struct mount *mnt) 90 { 91 return mnt != mnt->mnt_parent; 92 } 93 is_mounted(struct vfsmount * mnt)94static inline int is_mounted(struct vfsmount *mnt) 95 { 96 /* neither detached nor internal? */ 97 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns); 98 } 99 100 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); 101 102 extern int __legitimize_mnt(struct vfsmount *, unsigned); 103 __path_is_mountpoint(const struct path * path)104static inline bool __path_is_mountpoint(const struct path *path) 105 { 106 struct mount *m = __lookup_mnt(path->mnt, path->dentry); 107 return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT)); 108 } 109 110 extern void __detach_mounts(struct dentry *dentry); 111 detach_mounts(struct dentry * dentry)112static inline void detach_mounts(struct dentry *dentry) 113 { 114 if (!d_mountpoint(dentry)) 115 return; 116 __detach_mounts(dentry); 117 } 118 get_mnt_ns(struct mnt_namespace * ns)119static inline void get_mnt_ns(struct mnt_namespace *ns) 120 { 121 refcount_inc(&ns->ns.count); 122 } 123 124 extern seqlock_t mount_lock; 125 126 struct proc_mounts { 127 struct mnt_namespace *ns; 128 struct path root; 129 int (*show)(struct seq_file *, struct vfsmount *); 130 struct mount cursor; 131 }; 132 133 extern const struct seq_operations mounts_op; 134 135 extern bool __is_local_mountpoint(struct dentry *dentry); is_local_mountpoint(struct dentry * dentry)136static inline bool is_local_mountpoint(struct dentry *dentry) 137 { 138 if (!d_mountpoint(dentry)) 139 return false; 140 141 return __is_local_mountpoint(dentry); 142 } 143 is_anon_ns(struct mnt_namespace * ns)144static inline bool is_anon_ns(struct mnt_namespace *ns) 145 { 146 return ns->seq == 0; 147 } 148 149 extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor); 150