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
  20 #define MNT_NOSUID      0x01
  21 #define MNT_NODEV       0x02
  22 #define MNT_NOEXEC      0x04
  23 #define MNT_SHARED      0x10    /* if the vfsmount is a shared mount */
  24 #define MNT_UNBINDABLE  0x20    /* if the vfsmount is a unbindable mount */
  25
  26 #define MNT_PNODE_MASK  (MNT_SHARED | MNT_UNBINDABLE)
  27
  28 struct vfsmount {
  29         struct list_head mnt_hash;
  30         struct vfsmount *mnt_parent;    /* fs we are mounted on */
  31         struct dentry *mnt_mountpoint;  /* dentry of mountpoint */
  32         struct dentry *mnt_root;        /* root of the mounted tree */
  33         struct super_block *mnt_sb;     /* pointer to superblock */
  34         struct list_head mnt_mounts;    /* list of children, anchored here */
  35         struct list_head mnt_child;     /* and going through their mnt_child */
  36         atomic_t mnt_count;
  37         int mnt_flags;
  38         int mnt_expiry_mark;            /* true if marked for expiry */
  39         char *mnt_devname;              /* Name of device e.g. /dev/dsk/hda1 */
  40         struct list_head mnt_list;
  41         struct list_head mnt_expire;    /* link in fs-specific expiry list */
  42         struct list_head mnt_share;     /* circular list of shared mounts */
  43         struct list_head mnt_slave_list;/* list of slave mounts */
  44         struct list_head mnt_slave;     /* slave list entry */
  45         struct vfsmount *mnt_master;    /* slave is on master->mnt_slave_list */
  46         struct namespace *mnt_namespace; /* containing namespace */
  47         int mnt_pinned;
  48 };
  49
  50 static inline struct vfsmount *mntget(struct vfsmount *mnt)
  51 {
  52         if (mnt)
  53                 atomic_inc(&mnt->mnt_count);
  54         return mnt;
  55 }
  56
  57 extern void mntput_no_expire(struct vfsmount *mnt);
  58 extern void mnt_pin(struct vfsmount *mnt);
  59 extern void mnt_unpin(struct vfsmount *mnt);
  60
  61 static inline void mntput(struct vfsmount *mnt)
  62 {
  63         if (mnt) {
  64                 mnt->mnt_expiry_mark = 0;
  65                 mntput_no_expire(mnt);
  66         }
  67 }
  68
  69 extern void free_vfsmnt(struct vfsmount *mnt);
  70 extern struct vfsmount *alloc_vfsmnt(const char *name);
  71 extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
  72                                       const char *name, void *data);
  73
  74 struct nameidata;
  75
  76 extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
  77                         int mnt_flags, struct list_head *fslist);
  78
  79 extern void mark_mounts_for_expiry(struct list_head *mounts);
  80
  81 extern spinlock_t vfsmount_lock;
  82 extern dev_t name_to_dev_t(char *name);
  83
  84 #endif
  85 #endif /* _LINUX_MOUNT_H */