Line data    Source code

       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             : 
      84             : static inline struct mount *real_mount(struct vfsmount *mnt)
      85             : {
      86          45 :         return container_of(mnt, struct mount, mnt);
      87             : }
      88             : 
      89             : static inline int mnt_has_parent(struct mount *mnt)
      90             : {
      91           0 :         return mnt != mnt->mnt_parent;
      92             : }
      93             : 
      94             : static inline int is_mounted(struct vfsmount *mnt)
      95             : {
      96             :         /* neither detached nor internal? */
      97           0 :         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             : 
     104           0 : static inline bool __path_is_mountpoint(const struct path *path)
     105             : {
     106           0 :         struct mount *m = __lookup_mnt(path->mnt, path->dentry);
     107           0 :         return m && likely(!(m->mnt.mnt_flags & MNT_SYNC_UMOUNT));
     108             : }
     109             : 
     110             : extern void __detach_mounts(struct dentry *dentry);
     111             : 
     112             : static inline void detach_mounts(struct dentry *dentry)
     113             : {
     114           0 :         if (!d_mountpoint(dentry))
     115             :                 return;
     116           0 :         __detach_mounts(dentry);
     117             : }
     118             : 
     119             : static inline void get_mnt_ns(struct mnt_namespace *ns)
     120             : {
     121           2 :         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);
     136             : static inline bool is_local_mountpoint(struct dentry *dentry)
     137             : {
     138           0 :         if (!d_mountpoint(dentry))
     139             :                 return false;
     140             : 
     141           0 :         return __is_local_mountpoint(dentry);
     142             : }
     143             : 
     144             : static 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);