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 struct super_block;
  21 struct vfsmount;
  22 struct dentry;
  23 struct 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
  38 struct 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         int mnt_ghosts;
  65 };
  66
  67 static inline struct vfsmount *mntget(struct vfsmount *mnt)
  68 {
  69         if (mnt)
  70                 atomic_inc(&mnt->mnt_count);
  71         return mnt;
  72 }
  73
  74 extern void mntput_no_expire(struct vfsmount *mnt);
  75 extern void mnt_pin(struct vfsmount *mnt);
  76 extern void mnt_unpin(struct vfsmount *mnt);
  77
  78 static inline void mntput(struct vfsmount *mnt)
  79 {
  80         if (mnt) {
  81                 mnt->mnt_expiry_mark = 0;
  82                 mntput_no_expire(mnt);
  83         }
  84 }
  85
  86 extern void free_vfsmnt(struct vfsmount *mnt);
  87 extern struct vfsmount *alloc_vfsmnt(const char *name);
  88 extern struct vfsmount *do_kern_mount(const char *fstype, int flags,
  89                                       const char *name, void *data);
  90
  91 struct file_system_type;
  92 extern struct vfsmount *vfs_kern_mount(struct file_system_type *type,
  93                                       int flags, const char *name,
  94                                       void *data);
  95
  96 struct nameidata;
  97
  98 extern int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
  99                         int mnt_flags, struct list_head *fslist);
 100
 101 extern void mark_mounts_for_expiry(struct list_head *mounts);
 102
 103 extern spinlock_t vfsmount_lock;
 104 extern dev_t name_to_dev_t(char *name);
 105
 106 #endif
 107 #endif /* _LINUX_MOUNT_H */