fs/mount.h

   1 #include <linux/mount.h>
   2 #include <linux/seq_file.h>
   3 #include <linux/poll.h>
   4 #include <linux/ns_common.h>
   5 #include <linux/fs_pin.h>
   6
   7 struct mnt_namespace {
   8         atomic_t                count;
   9         struct ns_common        ns;
  10         struct mount *  root;
  11         struct list_head        list;
  12         struct user_namespace   *user_ns;
  13         u64                     seq;    /* Sequence number to prevent loops */
  14         wait_queue_head_t poll;
  15         u64 event;
  16 };
  17
  18 struct mnt_pcp {
  19         int mnt_count;
  20         int mnt_writers;
  21 };
  22
  23 struct mountpoint {
  24         struct hlist_node m_hash;
  25         struct dentry *m_dentry;
  26         struct hlist_head m_list;
  27         int m_count;
  28 };
  29
  30 struct mount {
  31         struct hlist_node mnt_hash;
  32         struct mount *mnt_parent;
  33         struct dentry *mnt_mountpoint;
  34         struct vfsmount mnt;
  35         union {
  36                 struct rcu_head mnt_rcu;
  37                 struct llist_node mnt_llist;
  38         };
  39 #ifdef CONFIG_SMP
  40         struct mnt_pcp __percpu *mnt_pcp;
  41 #else
  42         int mnt_count;
  43         int mnt_writers;
  44 #endif
  45         struct list_head mnt_mounts;    /* list of children, anchored here */
  46         struct list_head mnt_child;     /* and going through their mnt_child */
  47         struct list_head mnt_instance;  /* mount instance on sb->s_mounts */
  48         const char *mnt_devname;        /* Name of device e.g. /dev/dsk/hda1 */
  49         struct list_head mnt_list;
  50         struct list_head mnt_expire;    /* link in fs-specific expiry list */
  51         struct list_head mnt_share;     /* circular list of shared mounts */
  52         struct list_head mnt_slave_list;/* list of slave mounts */
  53         struct list_head mnt_slave;     /* slave list entry */
  54         struct mount *mnt_master;       /* slave is on master->mnt_slave_list */
  55         struct mnt_namespace *mnt_ns;   /* containing namespace */
  56         struct mountpoint *mnt_mp;      /* where is it mounted */
  57         struct hlist_node mnt_mp_list;  /* list mounts with the same mountpoint */
  58 #ifdef CONFIG_FSNOTIFY
  59         struct hlist_head mnt_fsnotify_marks;
  60         __u32 mnt_fsnotify_mask;
  61 #endif
  62         int mnt_id;                     /* mount identifier */
  63         int mnt_group_id;               /* peer group identifier */
  64         int mnt_expiry_mark;            /* true if marked for expiry */
  65         struct hlist_head mnt_pins;
  66         struct fs_pin mnt_umount;
  67         struct dentry *mnt_ex_mountpoint;
  68 };
  69
  70 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
  71
  72 static inline struct mount *real_mount(struct vfsmount *mnt)
  73 {
  74         return container_of(mnt, struct mount, mnt);
  75 }
  76
  77 static inline int mnt_has_parent(struct mount *mnt)
  78 {
  79         return mnt != mnt->mnt_parent;
  80 }
  81
  82 static inline int is_mounted(struct vfsmount *mnt)
  83 {
  84         /* neither detached nor internal? */
  85         return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
  86 }
  87
  88 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
  89 extern struct mount *__lookup_mnt_last(struct vfsmount *, struct dentry *);
  90
  91 extern int __legitimize_mnt(struct vfsmount *, unsigned);
  92 extern bool legitimize_mnt(struct vfsmount *, unsigned);
  93
  94 extern void __detach_mounts(struct dentry *dentry);
  95
  96 static inline void detach_mounts(struct dentry *dentry)
  97 {
  98         if (!d_mountpoint(dentry))
  99                 return;
 100         __detach_mounts(dentry);
 101 }
 102
 103 static inline void get_mnt_ns(struct mnt_namespace *ns)
 104 {
 105         atomic_inc(&ns->count);
 106 }
 107
 108 extern seqlock_t mount_lock;
 109
 110 static inline void lock_mount_hash(void)
 111 {
 112         write_seqlock(&mount_lock);
 113 }
 114
 115 static inline void unlock_mount_hash(void)
 116 {
 117         write_sequnlock(&mount_lock);
 118 }
 119
 120 struct proc_mounts {
 121         struct mnt_namespace *ns;
 122         struct path root;
 123         int (*show)(struct seq_file *, struct vfsmount *);
 124         void *cached_mount;
 125         u64 cached_event;
 126         loff_t cached_index;
 127 };
 128
 129 extern const struct seq_operations mounts_op;
 130
 131 extern bool __is_local_mountpoint(struct dentry *dentry);
 132 static inline bool is_local_mountpoint(struct dentry *dentry)
 133 {
 134         if (!d_mountpoint(dentry))
 135                 return false;
 136
 137         return __is_local_mountpoint(dentry);
 138 }