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 atomic_t count; 10 struct ns_common ns; 11 struct mount * root; 12 /* 13 * Traversal and modification of .list is protected by either 14 * - taking namespace_sem for write, OR 15 * - taking namespace_sem for read AND taking .ns_lock. 16 */ 17 struct list_head list; 18 spinlock_t ns_lock; 19 struct user_namespace *user_ns; 20 struct ucounts *ucounts; 21 u64 seq; /* Sequence number to prevent loops */ 22 wait_queue_head_t poll; 23 u64 event; 24 unsigned int mounts; /* # of mounts in the namespace */ 25 unsigned int pending_mounts; 26 } __randomize_layout; 27 28 struct mnt_pcp { 29 int mnt_count; 30 int mnt_writers; 31 }; 32 33 struct mountpoint { 34 struct hlist_node m_hash; 35 struct dentry *m_dentry; 36 struct hlist_head m_list; 37 int m_count; 38 }; 39 40 struct mount { 41 struct hlist_node mnt_hash; 42 struct mount *mnt_parent; 43 struct dentry *mnt_mountpoint; 44 struct vfsmount mnt; 45 union { 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 */ 77 int mnt_group_id; /* peer group identifier */ 78 int mnt_expiry_mark; /* true if marked for expiry */ 79 struct hlist_head mnt_pins; 80 struct hlist_head mnt_stuck_children; 81 } __randomize_layout; 82 83 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */ 84 85 static inline struct mount *real_mount(struct vfsmount *mnt) 86 { 87 return container_of(mnt, struct mount, mnt); 88 } 89 90 static inline int mnt_has_parent(struct mount *mnt) 91 { 92 return mnt != mnt->mnt_parent; 93 } 94 95 static inline int is_mounted(struct vfsmount *mnt) 96 { 97 /* neither detached nor internal? */ 98 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns); 99 } 100 101 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); 102 103 extern int __legitimize_mnt(struct vfsmount *, unsigned); 104 extern bool 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 atomic_inc(&ns->count); 124 } 125 126 extern seqlock_t mount_lock; 127 128 static inline void lock_mount_hash(void) 129 { 130 write_seqlock(&mount_lock); 131 } 132 133 static inline void unlock_mount_hash(void) 134 { 135 write_sequnlock(&mount_lock); 136 } 137 138 struct proc_mounts { 139 struct mnt_namespace *ns; 140 struct path root; 141 int (*show)(struct seq_file *, struct vfsmount *); 142 struct mount cursor; 143 }; 144 145 extern const struct seq_operations mounts_op; 146 147 extern bool __is_local_mountpoint(struct dentry *dentry); 148 static inline bool is_local_mountpoint(struct dentry *dentry) 149 { 150 if (!d_mountpoint(dentry)) 151 return false; 152 153 return __is_local_mountpoint(dentry); 154 } 155 156 static inline bool is_anon_ns(struct mnt_namespace *ns) 157 { 158 return ns->seq == 0; 159 } 160 161 extern void mnt_cursor_del(struct mnt_namespace *ns, struct mount *cursor); 162