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