69a73ae307fe0bb8c718b7a4bb90b6392bdc4248
[linux-2.6.git] / 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 /* Random magic number */
15 #define SYSFS_MAGIC 0x62656572
16
17 struct vfsmount *sysfs_mount;
18 struct super_block * sysfs_sb = NULL;
19 struct kmem_cache *sysfs_dir_cachep;
20
21 static const struct super_operations sysfs_ops = {
22         .statfs         = simple_statfs,
23         .drop_inode     = sysfs_delete_inode,
24 };
25
26 struct sysfs_dirent sysfs_root = {
27         .s_count        = ATOMIC_INIT(1),
28         .s_flags        = SYSFS_ROOT,
29         .s_mode         = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
30         .s_ino          = 1,
31 };
32
33 static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
34 {
35         struct inode *inode;
36         struct dentry *root;
37
38         sb->s_blocksize = PAGE_CACHE_SIZE;
39         sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
40         sb->s_magic = SYSFS_MAGIC;
41         sb->s_op = &sysfs_ops;
42         sb->s_time_gran = 1;
43         sysfs_sb = sb;
44
45         /* get root inode, initialize and unlock it */
46         inode = sysfs_get_inode(&sysfs_root);
47         if (!inode) {
48                 pr_debug("sysfs: could not get root inode\n");
49                 return -ENOMEM;
50         }
51
52         inode->i_op = &sysfs_dir_inode_operations;
53         inode->i_fop = &sysfs_dir_operations;
54         inc_nlink(inode); /* directory, account for "." */
55         unlock_new_inode(inode);
56
57         /* instantiate and link root dentry */
58         root = d_alloc_root(inode);
59         if (!root) {
60                 pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
61                 iput(inode);
62                 return -ENOMEM;
63         }
64         sysfs_root.s_dentry = root;
65         root->d_fsdata = &sysfs_root;
66         sb->s_root = root;
67         return 0;
68 }
69
70 static int sysfs_get_sb(struct file_system_type *fs_type,
71         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
72 {
73         return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
74 }
75
76 static struct file_system_type sysfs_fs_type = {
77         .name           = "sysfs",
78         .get_sb         = sysfs_get_sb,
79         .kill_sb        = kill_litter_super,
80 };
81
82 int __init sysfs_init(void)
83 {
84         int err = -ENOMEM;
85
86         sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
87                                               sizeof(struct sysfs_dirent),
88                                               0, 0, NULL);
89         if (!sysfs_dir_cachep)
90                 goto out;
91
92         err = register_filesystem(&sysfs_fs_type);
93         if (!err) {
94                 sysfs_mount = kern_mount(&sysfs_fs_type);
95                 if (IS_ERR(sysfs_mount)) {
96                         printk(KERN_ERR "sysfs: could not mount!\n");
97                         err = PTR_ERR(sysfs_mount);
98                         sysfs_mount = NULL;
99                         unregister_filesystem(&sysfs_fs_type);
100                         goto out_err;
101                 }
102         } else
103                 goto out_err;
104 out:
105         return err;
106 out_err:
107         kmem_cache_destroy(sysfs_dir_cachep);
108         sysfs_dir_cachep = NULL;
109         goto out;
110 }