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         unsigned int            mounts; /* # of mounts in the namespace */
  17         unsigned int            pending_mounts;
  18 };
  19
  20 struct mnt_pcp {
  21         int mnt_count;
  22         int mnt_writers;
  23 };
  24
  25 struct mountpoint {
  26         struct hlist_node m_hash;
  27         struct dentry *m_dentry;
  28         struct hlist_head m_list;
  29         int m_count;
  30 };
  31
  32 struct mount {
  33         struct hlist_node mnt_hash;
  34         struct mount *mnt_parent;
  35         struct dentry *mnt_mountpoint;
  36         struct vfsmount mnt;
  37         union {
  38                 struct rcu_head mnt_rcu;
  39                 struct llist_node mnt_llist;
  40         };
  41 #ifdef CONFIG_SMP
  42         struct mnt_pcp __percpu *mnt_pcp;
  43 #else
  44         int mnt_count;
  45         int mnt_writers;
  46 #endif
  47         struct list_head mnt_mounts;    /* list of children, anchored here */
  48         struct list_head mnt_child;     /* and going through their mnt_child */
  49         struct list_head mnt_instance;  /* mount instance on sb->s_mounts */
  50         const char *mnt_devname;        /* Name of device e.g. /dev/dsk/hda1 */
  51         struct list_head mnt_list;
  52         struct list_head mnt_expire;    /* link in fs-specific expiry list */
  53         struct list_head mnt_share;     /* circular list of shared mounts */
  54         struct list_head mnt_slave_list;/* list of slave mounts */
  55         struct list_head mnt_slave;     /* slave list entry */
  56         struct mount *mnt_master;       /* slave is on master->mnt_slave_list */
  57         struct mnt_namespace *mnt_ns;   /* containing namespace */
  58         struct mountpoint *mnt_mp;      /* where is it mounted */
  59         struct hlist_node mnt_mp_list;  /* list mounts with the same mountpoint */
  60 #ifdef CONFIG_FSNOTIFY
  61         struct hlist_head mnt_fsnotify_marks;
  62         __u32 mnt_fsnotify_mask;
  63 #endif
  64         int mnt_id;                     /* mount identifier */
  65         int mnt_group_id;               /* peer group identifier */
  66         int mnt_expiry_mark;            /* true if marked for expiry */
  67         struct hlist_head mnt_pins;
  68         struct fs_pin mnt_umount;
  69         struct dentry *mnt_ex_mountpoint;
  70 };
  71
  72 #define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
  73
  74 static inline struct mount *real_mount(struct vfsmount *mnt)
  75 {
  76         return container_of(mnt, struct mount, mnt);
  77 }
  78
  79 static inline int mnt_has_parent(struct mount *mnt)
  80 {
  81         return mnt != mnt->mnt_parent;
  82 }
  83
  84 static inline int is_mounted(struct vfsmount *mnt)
  85 {
  86         /* neither detached nor internal? */
  87         return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
  88 }
  89
  90 extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
  91
  92 extern int __legitimize_mnt(struct vfsmount *, unsigned);
  93 extern bool legitimize_mnt(struct vfsmount *, unsigned);
  94
  95 extern void __detach_mounts(struct dentry *dentry);
  96
  97 static inline void detach_mounts(struct dentry *dentry)
  98 {
  99         if (!d_mountpoint(dentry))
 100                 return;
 101         __detach_mounts(dentry);
 102 }
 103
 104 static inline void get_mnt_ns(struct mnt_namespace *ns)
 105 {
 106         atomic_inc(&ns->count);
 107 }
 108
 109 extern seqlock_t mount_lock;
 110
 111 static inline void lock_mount_hash(void)
 112 {
 113         write_seqlock(&mount_lock);
 114 }
 115
 116 static inline void unlock_mount_hash(void)
 117 {
 118         write_sequnlock(&mount_lock);
 119 }
 120
 121 struct proc_mounts {
 122         struct mnt_namespace *ns;
 123         struct path root;
 124         int (*show)(struct seq_file *, struct vfsmount *);
 125         void *cached_mount;
 126         u64 cached_event;
 127         loff_t cached_index;
 128 };
 129
 130 extern const struct seq_operations mounts_op;
 131
 132 extern bool __is_local_mountpoint(struct dentry *dentry);
 133 static inline bool is_local_mountpoint(struct dentry *dentry)
 134 {
 135         if (!d_mountpoint(dentry))
 136                 return false;
 137
 138         return __is_local_mountpoint(dentry);
 139 }