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 struct list_head list; 13 struct user_namespace *user_ns; 14 struct ucounts *ucounts; 15 u64 seq; /* Sequence number to prevent loops */ 16 wait_queue_head_t poll; 17 u64 event; 18 unsigned int mounts; /* # of mounts in the namespace */ 19 unsigned int pending_mounts; 20 } __randomize_layout; 21 22 struct mnt_pcp { 23 int mnt_count; 24 int mnt_writers; 25 }; 26 27 struct mountpoint { 28 struct hlist_node m_hash; 29 struct dentry *m_dentry; 30 struct hlist_head m_list; 31 int m_count; 32 }; 33 34 struct mount { 35 struct hlist_node mnt_hash; 36 struct mount *mnt_parent; 37 struct dentry *mnt_mountpoint; 38 struct vfsmount mnt; 39 union { 40 struct rcu_head mnt_rcu; 41 struct llist_node mnt_llist; 42 }; 43 #ifdef CONFIG_SMP 44 struct mnt_pcp __percpu *mnt_pcp; 45 #else 46 int mnt_count; 47 int mnt_writers; 48 #endif 49 struct list_head mnt_mounts; /* list of children, anchored here */ 50 struct list_head mnt_child; /* and going through their mnt_child */ 51 struct list_head mnt_instance; /* mount instance on sb->s_mounts */ 52 const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ 53 struct list_head mnt_list; 54 struct list_head mnt_expire; /* link in fs-specific expiry list */ 55 struct list_head mnt_share; /* circular list of shared mounts */ 56 struct list_head mnt_slave_list;/* list of slave mounts */ 57 struct list_head mnt_slave; /* slave list entry */ 58 struct mount *mnt_master; /* slave is on master->mnt_slave_list */ 59 struct mnt_namespace *mnt_ns; /* containing namespace */ 60 struct mountpoint *mnt_mp; /* where is it mounted */ 61 struct hlist_node mnt_mp_list; /* list mounts with the same mountpoint */ 62 struct list_head mnt_umounting; /* list entry for umount propagation */ 63 #ifdef CONFIG_FSNOTIFY 64 struct fsnotify_mark_connector __rcu *mnt_fsnotify_marks; 65 __u32 mnt_fsnotify_mask; 66 #endif 67 int mnt_id; /* mount identifier */ 68 int mnt_group_id; /* peer group identifier */ 69 int mnt_expiry_mark; /* true if marked for expiry */ 70 struct hlist_head mnt_pins; 71 struct fs_pin mnt_umount; 72 struct dentry *mnt_ex_mountpoint; 73 } __randomize_layout; 74 75 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */ 76 77 static inline struct mount *real_mount(struct vfsmount *mnt) 78 { 79 return container_of(mnt, struct mount, mnt); 80 } 81 82 static inline int mnt_has_parent(struct mount *mnt) 83 { 84 return mnt != mnt->mnt_parent; 85 } 86 87 static inline int is_mounted(struct vfsmount *mnt) 88 { 89 /* neither detached nor internal? */ 90 return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns); 91 } 92 93 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); 94 95 extern int __legitimize_mnt(struct vfsmount *, unsigned); 96 extern bool legitimize_mnt(struct vfsmount *, unsigned); 97 98 static inline bool __path_is_mountpoint(const struct path *path) 99 { 100 struct mount *m = __lookup_mnt(path->mnt, path->dentry); 101 return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT)); 102 } 103 104 extern void __detach_mounts(struct dentry *dentry); 105 106 static inline void detach_mounts(struct dentry *dentry) 107 { 108 if (!d_mountpoint(dentry)) 109 return; 110 __detach_mounts(dentry); 111 } 112 113 static inline void get_mnt_ns(struct mnt_namespace *ns) 114 { 115 atomic_inc(&ns->count); 116 } 117 118 extern seqlock_t mount_lock; 119 120 static inline void lock_mount_hash(void) 121 { 122 write_seqlock(&mount_lock); 123 } 124 125 static inline void unlock_mount_hash(void) 126 { 127 write_sequnlock(&mount_lock); 128 } 129 130 struct proc_mounts { 131 struct mnt_namespace *ns; 132 struct path root; 133 int (*show)(struct seq_file *, struct vfsmount *); 134 void *cached_mount; 135 u64 cached_event; 136 loff_t cached_index; 137 }; 138 139 extern const struct seq_operations mounts_op; 140 141 extern bool __is_local_mountpoint(struct dentry *dentry); 142 static inline bool is_local_mountpoint(struct dentry *dentry) 143 { 144 if (!d_mountpoint(dentry)) 145 return false; 146 147 return __is_local_mountpoint(dentry); 148 } 149