LXR linux/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
   7struct 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};
  17
  18struct mnt_pcp {
  19        int mnt_count;
  20        int mnt_writers;
  21};
  22
  23struct mountpoint {
  24        struct hlist_node m_hash;
  25        struct dentry *m_dentry;
  26        struct hlist_head m_list;
  27        int m_count;
  28};
  29
  30struct mount {
  31        struct hlist_node mnt_hash;
  32        struct mount *mnt_parent;
  33        struct dentry *mnt_mountpoint;
  34        struct vfsmount mnt;
  35        union {
  36                struct rcu_head mnt_rcu;
  37                struct llist_node mnt_llist;
  38        };
  39#ifdef CONFIG_SMP
  40        struct mnt_pcp __percpu *mnt_pcp;
  41#else
  42        int mnt_count;
  43        int mnt_writers;
  44#endif
  45        struct list_head mnt_mounts;    /* list of children, anchored here */
  46        struct list_head mnt_child;     /* and going through their mnt_child */
  47        struct list_head mnt_instance;  /* mount instance on sb->s_mounts */
  48        const char *mnt_devname;        /* Name of device e.g. /dev/dsk/hda1 */
  49        struct list_head mnt_list;
  50        struct list_head mnt_expire;    /* link in fs-specific expiry list */
  51        struct list_head mnt_share;     /* circular list of shared mounts */
  52        struct list_head mnt_slave_list;/* list of slave mounts */
  53        struct list_head mnt_slave;     /* slave list entry */
  54        struct mount *mnt_master;       /* slave is on master->mnt_slave_list */
  55        struct mnt_namespace *mnt_ns;   /* containing namespace */
  56        struct mountpoint *mnt_mp;      /* where is it mounted */
  57        struct hlist_node mnt_mp_list;  /* list mounts with the same mountpoint */
  58#ifdef CONFIG_FSNOTIFY
  59        struct hlist_head mnt_fsnotify_marks;
  60        __u32 mnt_fsnotify_mask;
  61#endif
  62        int mnt_id;                     /* mount identifier */
  63        int mnt_group_id;               /* peer group identifier */
  64        int mnt_expiry_mark;            /* true if marked for expiry */
  65        struct hlist_head mnt_pins;
  66        struct fs_pin mnt_umount;
  67        struct dentry *mnt_ex_mountpoint;
  68};
  69
  70#define MNT_NS_INTERNAL ERR_PTR(-EINVAL) /* distinct from any mnt_namespace */
  71
  72static inline struct mount *real_mount(struct vfsmount *mnt)
  73{
  74        return container_of(mnt, struct mount, mnt);
  75}
  76
  77static inline int mnt_has_parent(struct mount *mnt)
  78{
  79        return mnt != mnt->mnt_parent;
  80}
  81
  82static inline int is_mounted(struct vfsmount *mnt)
  83{
  84        /* neither detached nor internal? */
  85        return !IS_ERR_OR_NULL(real_mount(mnt)->mnt_ns);
  86}
  87
  88extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *);
  89extern struct mount *__lookup_mnt_last(struct vfsmount *, struct dentry *);
  90
  91extern int __legitimize_mnt(struct vfsmount *, unsigned);
  92extern bool legitimize_mnt(struct vfsmount *, unsigned);
  93
  94extern void __detach_mounts(struct dentry *dentry);
  95
  96static inline void detach_mounts(struct dentry *dentry)
  97{
  98        if (!d_mountpoint(dentry))
  99                return;
 100        __detach_mounts(dentry);
 101}
 102
 103static inline void get_mnt_ns(struct mnt_namespace *ns)
 104{
 105        atomic_inc(&ns->count);
 106}
 107
 108extern seqlock_t mount_lock;
 109
 110static inline void lock_mount_hash(void)
 111{
 112        write_seqlock(&mount_lock);
 113}
 114
 115static inline void unlock_mount_hash(void)
 116{
 117        write_sequnlock(&mount_lock);
 118}
 119
 120struct proc_mounts {
 121        struct mnt_namespace *ns;
 122        struct path root;
 123        int (*show)(struct seq_file *, struct vfsmount *);
 124        void *cached_mount;
 125        u64 cached_event;
 126        loff_t cached_index;
 127};
 128
 129extern const struct seq_operations mounts_op;
 130
 131extern bool __is_local_mountpoint(struct dentry *dentry);
 132static 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}
 139