fs/sysfs/mount.c

   1 /*
   2  * mount.c - operations for initializing and mounting sysfs.
   3  */
   4
   5 #define DEBUG
   6
   7 #include <linux/fs.h>
   8 #include <linux/mount.h>
   9 #include <linux/pagemap.h>
  10 #include <linux/init.h>
  11
  12 #include "sysfs.h"
  13
  14
  15 struct vfsmount *sysfs_mount;
  16 struct super_block * sysfs_sb = NULL;
  17
  18 static struct super_operations sysfs_ops = {
  19         .statfs         = simple_statfs,
  20         .drop_inode     = generic_delete_inode,
  21 };
  22
  23 static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
  24 {
  25         struct inode *inode;
  26         struct dentry *root;
  27
  28         sb->s_blocksize = PAGE_CACHE_SIZE;
  29         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
  30         sb->s_magic = SYSFS_SUPER_MAGIC;
  31         sb->s_op = &sysfs_ops;
  32         sysfs_sb = sb;
  33
  34         inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
  35         if (inode) {
  36                 inode->i_op = &simple_dir_inode_operations;
  37                 inode->i_fop = &simple_dir_operations;
  38                 /* directory inodes start off with i_nlink == 2 (for "." entry) */
  39                 inode->i_nlink++;
  40         } else {
  41                 pr_debug("sysfs: could not get root inode\n");
  42                 return -ENOMEM;
  43         }
  44
  45         root = d_alloc_root(inode);
  46         if (!root) {
  47                 pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
  48                 iput(inode);
  49                 return -ENOMEM;
  50         }
  51         sb->s_root = root;
  52         return 0;
  53 }
  54
  55 static struct super_block *sysfs_get_sb(struct file_system_type *fs_type,
  56         int flags, const char *dev_name, void *data)
  57 {
  58         return get_sb_single(fs_type, flags, data, sysfs_fill_super);
  59 }
  60
  61 static struct file_system_type sysfs_fs_type = {
  62         .name           = "sysfs",
  63         .get_sb         = sysfs_get_sb,
  64         .kill_sb        = kill_litter_super,
  65 };
  66
  67 int __init sysfs_init(void)
  68 {
  69         int err;
  70
  71         err = register_filesystem(&sysfs_fs_type);
  72         if (!err) {
  73                 sysfs_mount = kern_mount(&sysfs_fs_type);
  74                 if (IS_ERR(sysfs_mount)) {
  75                         printk(KERN_ERR "sysfs: could not mount!\n");
  76                         err = PTR_ERR(sysfs_mount);
  77                         sysfs_mount = NULL;
  78                 }
  79         }
  80         return err;
  81 }