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 */
   9#ifndef _LINUX_MOUNT_H
  10#define _LINUX_MOUNT_H
  11
  12#include <linux/types.h>
  13#include <linux/list.h>
  14#include <linux/nodemask.h>
  15#include <linux/spinlock.h>
  16#include <asm/atomic.h>
  17
  18struct super_block;
  19struct vfsmount;
  20struct dentry;
  21struct mnt_namespace;
  22
  23#define MNT_NOSUID      0x01
  24#define MNT_NODEV       0x02
  25#define MNT_NOEXEC      0x04
  26#define MNT_NOATIME     0x08
  27#define MNT_NODIRATIME  0x10
  28#define MNT_RELATIME    0x20
  29#define MNT_READONLY    0x40    /* does the user want this to be r/o? */
  30#define MNT_STRICTATIME 0x80
  31
  32#define MNT_SHRINKABLE  0x100
  33#define MNT_IMBALANCED_WRITE_COUNT      0x200 /* just for debugging */
  34
  35#define MNT_SHARED      0x1000  /* if the vfsmount is a shared mount */
  36#define MNT_UNBINDABLE  0x2000  /* if the vfsmount is a unbindable mount */
  37#define MNT_PNODE_MASK  0x3000  /* propagation flag mask */
  38
  39struct vfsmount {
  40        struct list_head mnt_hash;
  41        struct vfsmount *mnt_parent;    /* fs we are mounted on */
  42        struct dentry *mnt_mountpoint;  /* dentry of mountpoint */
  43        struct dentry *mnt_root;        /* root of the mounted tree */
  44        struct super_block *mnt_sb;     /* pointer to superblock */
  45        struct list_head mnt_mounts;    /* list of children, anchored here */
  46        struct list_head mnt_child;     /* and going through their mnt_child */
  47        int mnt_flags;
  48        /* 4 bytes hole on 64bits arches */
  49        const char *mnt_devname;        /* Name of device e.g. /dev/dsk/hda1 */
  50        struct list_head mnt_list;
  51        struct list_head mnt_expire;    /* link in fs-specific expiry list */
  52        struct list_head mnt_share;     /* circular list of shared mounts */
  53        struct list_head mnt_slave_list;/* list of slave mounts */
  54        struct list_head mnt_slave;     /* slave list entry */
  55        struct vfsmount *mnt_master;    /* slave is on master->mnt_slave_list */
  56        struct mnt_namespace *mnt_ns;   /* containing namespace */
  57        int mnt_id;                     /* mount identifier */
  58        int mnt_group_id;               /* peer group identifier */
  59        /*
  60         * We put mnt_count & mnt_expiry_mark at the end of struct vfsmount
  61         * to let these frequently modified fields in a separate cache line
  62         * (so that reads of mnt_flags wont ping-pong on SMP machines)
  63         */
  64        atomic_t mnt_count;
  65        int mnt_expiry_mark;            /* true if marked for expiry */
  66        int mnt_pinned;
  67        int mnt_ghosts;
  68        /*
  69         * This value is not stable unless all of the mnt_writers[] spinlocks
  70         * are held, and all mnt_writer[]s on this mount have 0 as their ->count
  71         */
  72        atomic_t __mnt_writers;
  73};
  74
  75static inline struct vfsmount *mntget(struct vfsmount *mnt)
  76{
  77        if (mnt)
  78                atomic_inc(&mnt->mnt_count);
  79        return mnt;
  80}
  81
  82extern int mnt_want_write(struct vfsmount *mnt);
  83extern void mnt_drop_write(struct vfsmount *mnt);
  84extern void mntput_no_expire(struct vfsmount *mnt);
  85extern void mnt_pin(struct vfsmount *mnt);
  86extern void mnt_unpin(struct vfsmount *mnt);
  87extern int __mnt_is_readonly(struct vfsmount *mnt);
  88
  89static inline void mntput(struct vfsmount *mnt)
  90{
  91        if (mnt) {
  92                mnt->mnt_expiry_mark = 0;
  93                mntput_no_expire(mnt);
  94        }
  95}
  96
  97extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
  98                                      const char *name, void *data);
  99
 100struct file_system_type;
 101extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
 102                                      int flags, const char *name,
 103                                      void *data);
 104
 105struct nameidata;
 106
 107struct path;
 108extern int do_add_mount(struct vfsmount *newmnt, struct path *path,
 109                        int mnt_flags, struct list_head *fslist);
 110
 111extern void mark_mounts_for_expiry(struct list_head *mounts);
 112
 113extern spinlock_t vfsmount_lock;
 114extern dev_t name_to_dev_t(char *name);
 115
 116#endif /* _LINUX_MOUNT_H */
 117