fs/mount.h

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