blob: 23a48a38e6af01455575083f8242ef4538f76cac [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Oliver Neukum94bebf42006-12-20 10:52:44 +010011#include <asm/semaphore.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012
13#include "sysfs.h"
14
15/* Random magic number */
16#define SYSFS_MAGIC 0x62656572
17
18struct vfsmount *sysfs_mount;
19struct super_block * sysfs_sb = NULL;
Christoph Lametere18b8902006-12-06 20:33:20 -080020struct kmem_cache *sysfs_dir_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
Oliver Neukum94bebf42006-12-20 10:52:44 +010022static void sysfs_clear_inode(struct inode *inode);
23
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -080024static const struct super_operations sysfs_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 .statfs = simple_statfs,
Eric W. Biedermanb592fcf2007-01-24 12:35:52 -070026 .drop_inode = sysfs_delete_inode,
Oliver Neukum94bebf42006-12-20 10:52:44 +010027 .clear_inode = sysfs_clear_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -070028};
29
30static struct sysfs_dirent sysfs_root = {
31 .s_sibling = LIST_HEAD_INIT(sysfs_root.s_sibling),
32 .s_children = LIST_HEAD_INIT(sysfs_root.s_children),
33 .s_element = NULL,
34 .s_type = SYSFS_ROOT,
Maneesh Soni82155342005-05-31 10:39:52 +053035 .s_iattr = NULL,
Linus Torvalds1da177e2005-04-16 15:20:36 -070036};
37
Oliver Neukum94bebf42006-12-20 10:52:44 +010038static void sysfs_clear_inode(struct inode *inode)
39{
40 kfree(inode->i_private);
41}
42
Linus Torvalds1da177e2005-04-16 15:20:36 -070043static 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
Maneesh Soni82155342005-05-31 10:39:52 +053055 inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
56 &sysfs_root);
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 if (inode) {
58 inode->i_op = &sysfs_dir_inode_operations;
59 inode->i_fop = &sysfs_dir_operations;
60 /* directory inodes start off with i_nlink == 2 (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -070061 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 } else {
63 pr_debug("sysfs: could not get root inode\n");
64 return -ENOMEM;
65 }
66
67 root = d_alloc_root(inode);
68 if (!root) {
69 pr_debug("%s: could not get root dentry!\n",__FUNCTION__);
70 iput(inode);
71 return -ENOMEM;
72 }
73 root->d_fsdata = &sysfs_root;
74 sb->s_root = root;
75 return 0;
76}
77
David Howells454e2392006-06-23 02:02:57 -070078static int sysfs_get_sb(struct file_system_type *fs_type,
79 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -070080{
David Howells454e2392006-06-23 02:02:57 -070081 return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082}
83
84static struct file_system_type sysfs_fs_type = {
85 .name = "sysfs",
86 .get_sb = sysfs_get_sb,
87 .kill_sb = kill_litter_super,
88};
89
90int __init sysfs_init(void)
91{
92 int err = -ENOMEM;
93
94 sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
95 sizeof(struct sysfs_dirent),
96 0, 0, NULL, NULL);
97 if (!sysfs_dir_cachep)
98 goto out;
99
100 err = register_filesystem(&sysfs_fs_type);
101 if (!err) {
102 sysfs_mount = kern_mount(&sysfs_fs_type);
103 if (IS_ERR(sysfs_mount)) {
104 printk(KERN_ERR "sysfs: could not mount!\n");
105 err = PTR_ERR(sysfs_mount);
106 sysfs_mount = NULL;
107 unregister_filesystem(&sysfs_fs_type);
108 goto out_err;
109 }
110 } else
111 goto out_err;
112out:
113 return err;
114out_err:
115 kmem_cache_destroy(sysfs_dir_cachep);
116 sysfs_dir_cachep = NULL;
117 goto out;
118}