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         struct rcu_head mnt_rcu;
  33 #ifdef CONFIG_SMP
  34         struct mnt_pcp __percpu *mnt_pcp;
  35 #else
  36         int mnt_count;
  37         int mnt_writers;
  38 #endif
  39         struct list_head mnt_mounts;    /* list of children, anchored here */
  40         struct list_head mnt_child;     /* and going through their mnt_child */
  41         struct list_head mnt_instance;  /* mount instance on sb->s_mounts */
  42         const char *mnt_devname;        /* Name of device e.g. /dev/dsk/hda1 */
  43         struct list_head mnt_list;
  44         struct list_head mnt_expire;    /* link in fs-specific expiry list */
  45         struct list_head mnt_share;     /* circular list of shared mounts */
  46         struct list_head mnt_slave_list;/* list of slave mounts */
  47         struct list_head mnt_slave;     /* slave list entry */
  48         struct mount *mnt_master;       /* slave is on master->mnt_slave_list */
  49         struct mnt_namespace *mnt_ns;   /* containing namespace */
  50         struct mountpoint *mnt_mp;      /* where is it mounted */
  51 #ifdef CONFIG_FSNOTIFY
  52         struct hlist_head mnt_fsnotify_marks;
  53         __u32 mnt_fsnotify_mask;
  54 #endif
  55         int mnt_id;                     /* mount identifier */
  56         int mnt_group_id;               /* peer group identifier */
  57         int mnt_expiry_mark;            /* true if marked for expiry */
  58         struct hlist_head mnt_pins;
  59         struct path mnt_ex_mountpoint;
  60 };
  61
  62 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
  63
  64 static inline struct mount *real_mount(struct vfsmount *mnt)
  65 {
  66         return container_of(mnt, struct mount, mnt);
  67 }
  68
  69 static inline int mnt_has_parent(struct mount *mnt)
  70 {
  71         return mnt != mnt->mnt_parent;
  72 }
  73
  74 static inline int is_mounted(struct vfsmount *mnt)
  75 {
  76         /* neither detached nor internal? */
  77         return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
  78 }
  79
  80 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
  81 extern struct mount *__lookup_mnt_last(struct vfsmount *, struct dentry *);
  82
  83 extern bool legitimize_mnt(struct vfsmount *, unsigned);
  84
  85 static inline void get_mnt_ns(struct mnt_namespace *ns)
  86 {
  87         atomic_inc(&ns->count);
  88 }
  89
  90 extern seqlock_t mount_lock;
  91
  92 static inline void lock_mount_hash(void)
  93 {
  94         write_seqlock(&mount_lock);
  95 }
  96
  97 static inline void unlock_mount_hash(void)
  98 {
  99         write_sequnlock(&mount_lock);
 100 }
 101
 102 struct proc_mounts {
 103         struct seq_file m;
 104         struct mnt_namespace *ns;
 105         struct path root;
 106         int (*show)(struct seq_file *, struct vfsmount *);
 107         void *cached_mount;
 108         u64 cached_event;
 109         loff_t cached_index;
 110 };
 111
 112 #define proc_mounts(p) (container_of((p), struct proc_mounts, m))
 113
 114 extern const struct seq_operations mounts_op;