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