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
  14#include <linux/types.h>
  15#include <linux/list.h>
  16#include <linux/nodemask.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#define MNT_READONLY    0x40    /* does the user want this to be r/o? */
  32
  33#define MNT_SHRINKABLE  0x100
  34#define MNT_IMBALANCED_WRITE_COUNT      0x200 /* just for debugging */
  35
  36#define MNT_SHARED      0x1000  /* if the vfsmount is a shared mount */
  37#define MNT_UNBINDABLE  0x2000  /* if the vfsmount is a unbindable mount */
  38#define MNT_PNODE_MASK  0x3000  /* propagation flag mask */
  39
  40struct vfsmount {
  41        struct list_head mnt_hash;
  42        struct vfsmount *mnt_parent;    /* fs we are mounted on */
  43        struct dentry *mnt_mountpoint;  /* dentry of mountpoint */
  44        struct dentry *mnt_root;        /* root of the mounted tree */
  45        struct super_block *mnt_sb;     /* pointer to superblock */
  46        struct list_head mnt_mounts;    /* list of children, anchored here */
  47        struct list_head mnt_child;     /* and going through their mnt_child */
  48        int mnt_flags;
  49        /* 4 bytes hole on 64bits arches */
  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 vfsmount *mnt_master;    /* slave is on master->mnt_slave_list */
  57        struct mnt_namespace *mnt_ns;   /* containing namespace */
  58        int mnt_id;                     /* mount identifier */
  59        int mnt_group_id;               /* peer group identifier */
  60        /*
  61         * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
  62         * to let these frequently modified fields in a separate cache line
  63         * (so that reads of mnt_flags wont ping-pong on SMP machines)
  64         */
  65        atomic_t mnt_count;
  66        int mnt_expiry_mark;            /* true if marked for expiry */
  67        int mnt_pinned;
  68        int mnt_ghosts;
  69        /*
  70         * This value is not stable unless all of the mnt_writers[] spinlocks
  71         * are held, and all mnt_writer[]s on this mount have 0 as their ->count
  72         */
  73        atomic_t __mnt_writers;
  74};
  75
  76static inline struct vfsmount *mntget(struct vfsmount *mnt)
  77{
  78        if (mnt)
  79                atomic_inc(&mnt->mnt_count);
  80        return mnt;
  81}
  82
  83extern int mnt_want_write(struct vfsmount *mnt);
  84extern void mnt_drop_write(struct vfsmount *mnt);
  85extern void mntput_no_expire(struct vfsmount *mnt);
  86extern void mnt_pin(struct vfsmount *mnt);
  87extern void mnt_unpin(struct vfsmount *mnt);
  88extern int __mnt_is_readonly(struct vfsmount *mnt);
  89
  90static inline void mntput(struct vfsmount *mnt)
  91{
  92        if (mnt) {
  93                mnt->mnt_expiry_mark = 0;
  94                mntput_no_expire(mnt);
  95        }
  96}
  97
  98extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
  99                                      const char *name, void *data);
 100
 101struct file_system_type;
 102extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
 103                                      int flags, const char *name,
 104                                      void *data);
 105
 106struct nameidata;
 107
 108struct path;
 109extern int do_add_mount(struct vfsmount *newmnt, struct path *path,
 110                        int mnt_flags, struct list_head *fslist);
 111
 112extern void mark_mounts_for_expiry(struct list_head *mounts);
 113
 114extern spinlock_t vfsmount_lock;
 115extern dev_t name_to_dev_t(char *name);
 116
 117#endif /* _LINUX_MOUNT_H */
 118