drivers/xen/xenfs/super.c

   1 /*
   2  *  xenfs.c - a filesystem for passing info between the a domain and
   3  *  the hypervisor.
   4  *
   5  * 2008-10-07  Alex Zeffertt    Replaced /proc/xen/xenbus with xenfs filesystem
   6  *                              and /proc/xen compatibility mount point.
   7  *                              Turned xenfs into a loadable module.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/errno.h>
  12 #include <linux/module.h>
  13 #include <linux/fs.h>
  14 #include <linux/magic.h>
  15
  16 #include "xenfs.h"
  17
  18 #include <asm/xen/hypervisor.h>
  19
  20 MODULE_DESCRIPTION("Xen filesystem");
  21 MODULE_LICENSE("GPL");
  22
  23 static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
  24 {
  25         static struct tree_descr xenfs_files[] = {
  26                 [2] = {"xenbus", &xenbus_file_ops, S_IRUSR|S_IWUSR},
  27                 {""},
  28         };
  29
  30         return simple_fill_super(sb, XENFS_SUPER_MAGIC, xenfs_files);
  31 }
  32
  33 static int xenfs_get_sb(struct file_system_type *fs_type,
  34                         int flags, const char *dev_name,
  35                         void *data, struct vfsmount *mnt)
  36 {
  37         return get_sb_single(fs_type, flags, data, xenfs_fill_super, mnt);
  38 }
  39
  40 static struct file_system_type xenfs_type = {
  41         .owner =        THIS_MODULE,
  42         .name =         "xenfs",
  43         .get_sb =       xenfs_get_sb,
  44         .kill_sb =      kill_litter_super,
  45 };
  46
  47 static int __init xenfs_init(void)
  48 {
  49         if (xen_pv_domain())
  50                 return register_filesystem(&xenfs_type);
  51
  52         printk(KERN_INFO "XENFS: not registering filesystem on non-xen platform\n");
  53         return 0;
  54 }
  55
  56 static void __exit xenfs_exit(void)
  57 {
  58         if (xen_pv_domain())
  59                 unregister_filesystem(&xenfs_type);
  60 }
  61
  62 module_init(xenfs_init);
  63 module_exit(xenfs_exit);
  64