LXR linux/include/linux/mount.h

   1/*
   2 *
   3 * Definitions for mount interface. This describes the in the kernel build 
   4 * linkedlist with mounted filesystems.
   5 *
   6 * Author:  Marco van Wieringen <mvw@planets.elm.net>
   7 *
   8 * Version: $Id: mount.h,v 2.0 1996/11/17 16:48:14 mvw Exp mvw $
   9 *
  10 */
  11#ifndef _LINUX_MOUNT_H
  12#define _LINUX_MOUNT_H
  13#ifdef __KERNEL__
  14
  15#include <linux/types.h>
  16#include <linux/list.h>
  17#include <linux/spinlock.h>
  18#include <asm/atomic.h>
  19
  20struct super_block;
  21struct vfsmount;
  22struct dentry;
  23struct mnt_namespace;
  24
  25#define MNT_NOSUID      0x01
  26#define MNT_NODEV       0x02
  27#define MNT_NOEXEC      0x04
  28#define MNT_NOATIME     0x08
  29#define MNT_NODIRATIME  0x10
  30#define MNT_RELATIME    0x20
  31
  32#define MNT_SHRINKABLE  0x100
  33
  34#define MNT_SHARED      0x1000  /* if the vfsmount is a shared mount */
  35#define MNT_UNBINDABLE  0x2000  /* if the vfsmount is a unbindable mount */
  36#define MNT_PNODE_MASK  0x3000  /* propagation flag mask */
  37
  38struct vfsmount {
  39        struct list_head mnt_hash;
  40        struct vfsmount *mnt_parent;    /* fs we are mounted on */
  41        struct dentry *mnt_mountpoint;  /* dentry of mountpoint */
  42        struct dentry *mnt_root;        /* root of the mounted tree */
  43        struct super_block *mnt_sb;     /* pointer to superblock */
  44        struct list_head mnt_mounts;    /* list of children, anchored here */
  45        struct list_head mnt_child;     /* and going through their mnt_child */
  46        int mnt_flags;
  47        /* 4 bytes hole on 64bits arches */
  48        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 vfsmount *mnt_master;    /* slave is on master->mnt_slave_list */
  55        struct mnt_namespace *mnt_ns;   /* containing namespace */
  56        /*
  57         * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
  58         * to let these frequently modified fields in a separate cache line
  59         * (so that reads of mnt_flags wont ping-pong on SMP machines)
  60         */
  61        atomic_t mnt_count;
  62        int mnt_expiry_mark;            /* true if marked for expiry */
  63        int mnt_pinned;
  64};
  65
  66static inline struct vfsmount *mntget(struct vfsmount *mnt)
  67{
  68        if (mnt)
  69                atomic_inc(&mnt->mnt_count);
  70        return mnt;
  71}
  72
  73extern void mntput_no_expire(struct vfsmount *mnt);
  74extern void mnt_pin(struct vfsmount *mnt);
  75extern void mnt_unpin(struct vfsmount *mnt);
  76
  77static inline void mntput(struct vfsmount *mnt)
  78{
  79        if (mnt) {
  80                mnt->mnt_expiry_mark = 0;
  81                mntput_no_expire(mnt);
  82        }
  83}
  84
  85extern void free_vfsmnt(struct vfsmount *mnt);
  86extern struct vfsmount *alloc_vfsmnt(const char *name);
  87extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
  88                                      const char *name, void *data);
  89
  90struct file_system_type;
  91extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
  92                                      int flags, const char *name,
  93                                      void *data);
  94
  95struct nameidata;
  96
  97extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
  98                        int mnt_flags, struct list_head *fslist);
  99
 100extern void mark_mounts_for_expiry(struct list_head *mounts);
 101extern void shrink_submounts(struct vfsmount *mountpoint, struct list_head *mounts);
 102
 103extern spinlock_t vfsmount_lock;
 104extern dev_t name_to_dev_t(char *name);
 105
 106#endif
 107#endif /* _LINUX_MOUNT_H */
 108