LXR linux/fs/sysfs/mount.c

   1/*
   2 * fs/sysfs/symlink.c - operations for initializing and mounting sysfs
   3 *
   4 * Copyright (c) 2001-3 Patrick Mochel
   5 * Copyright (c) 2007 SUSE Linux Products GmbH
   6 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
   7 *
   8 * This file is released under the GPLv2.
   9 *
  10 * Please see Documentation/filesystems/sysfs.txt for more information.
  11 */
  12
  13#define DEBUG 
  14
  15#include <linux/fs.h>
  16#include <linux/mount.h>
  17#include <linux/pagemap.h>
  18#include <linux/init.h>
  19#include <linux/module.h>
  20#include <linux/magic.h>
  21
  22#include "sysfs.h"
  23
  24
  25static struct vfsmount *sysfs_mount;
  26struct super_block * sysfs_sb = NULL;
  27struct kmem_cache *sysfs_dir_cachep;
  28
  29static const struct super_operations sysfs_ops = {
  30        .statfs         = simple_statfs,
  31        .drop_inode     = generic_delete_inode,
  32        .delete_inode   = sysfs_delete_inode,
  33};
  34
  35struct sysfs_dirent sysfs_root = {
  36        .s_name         = "",
  37        .s_count        = ATOMIC_INIT(1),
  38        .s_flags        = SYSFS_DIR,
  39        .s_mode         = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
  40        .s_ino          = 1,
  41};
  42
  43static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
  44{
  45        struct inode *inode;
  46        struct dentry *root;
  47
  48        sb->s_blocksize = PAGE_CACHE_SIZE;
  49        sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
  50        sb->s_magic = SYSFS_MAGIC;
  51        sb->s_op = &sysfs_ops;
  52        sb->s_time_gran = 1;
  53        sysfs_sb = sb;
  54
  55        /* get root inode, initialize and unlock it */
  56        mutex_lock(&sysfs_mutex);
  57        inode = sysfs_get_inode(&sysfs_root);
  58        mutex_unlock(&sysfs_mutex);
  59        if (!inode) {
  60                pr_debug("sysfs: could not get root inode\n");
  61                return -ENOMEM;
  62        }
  63
  64        /* instantiate and link root dentry */
  65        root = d_alloc_root(inode);
  66        if (!root) {
  67                pr_debug("%s: could not get root dentry!\n",__func__);
  68                iput(inode);
  69                return -ENOMEM;
  70        }
  71        root->d_fsdata = &sysfs_root;
  72        sb->s_root = root;
  73        return 0;
  74}
  75
  76static int sysfs_get_sb(struct file_system_type *fs_type,
  77        int flags, const char *dev_name, void *data, struct vfsmount *mnt)
  78{
  79        return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
  80}
  81
  82static struct file_system_type sysfs_fs_type = {
  83        .name           = "sysfs",
  84        .get_sb         = sysfs_get_sb,
  85        .kill_sb        = kill_anon_super,
  86};
  87
  88int __init sysfs_init(void)
  89{
  90        int err = -ENOMEM;
  91
  92        sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
  93                                              sizeof(struct sysfs_dirent),
  94                                              0, 0, NULL);
  95        if (!sysfs_dir_cachep)
  96                goto out;
  97
  98        err = sysfs_inode_init();
  99        if (err)
 100                goto out_err;
 101
 102        err = register_filesystem(&sysfs_fs_type);
 103        if (!err) {
 104                sysfs_mount = kern_mount(&sysfs_fs_type);
 105                if (IS_ERR(sysfs_mount)) {
 106                        printk(KERN_ERR "sysfs: could not mount!\n");
 107                        err = PTR_ERR(sysfs_mount);
 108                        sysfs_mount = NULL;
 109                        unregister_filesystem(&sysfs_fs_type);
 110                        goto out_err;
 111                }
 112        } else
 113                goto out_err;
 114out:
 115        return err;
 116out_err:
 117        kmem_cache_destroy(sysfs_dir_cachep);
 118        sysfs_dir_cachep = NULL;
 119        goto out;
 120}
 121
 122#undef sysfs_get
 123struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
 124{
 125        return __sysfs_get(sd);
 126}
 127EXPORT_SYMBOL_GPL(sysfs_get);
 128
 129#undef sysfs_put
 130void sysfs_put(struct sysfs_dirent *sd)
 131{
 132        __sysfs_put(sd);
 133}
 134EXPORT_SYMBOL_GPL(sysfs_put);
 135