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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Tejun Heo6d66f5c2007-09-20 17:31:38 +09002 * 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 */
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>
Neil Brownf1282c82008-07-16 08:58:04 +100019#include <linux/module.h>
Qinghuang Feng8231f2f2009-01-14 15:45:13 +080020#include <linux/magic.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090021#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
23#include "sysfs.h"
24
Linus Torvalds1da177e2005-04-16 15:20:36 -070025
Eric W. Biederman7d0c7d62007-08-20 21:36:30 +090026static struct vfsmount *sysfs_mount;
Christoph Lametere18b8902006-12-06 20:33:20 -080027struct kmem_cache *sysfs_dir_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -070028
Josef 'Jeff' Sipekee9b6d62007-02-12 00:55:41 -080029static const struct super_operations sysfs_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070030 .statfs = simple_statfs,
Eric W. Biederman90bc6132007-07-31 19:15:08 +090031 .drop_inode = generic_delete_inode,
Eric W. Biederman04256b42009-02-11 13:20:23 -080032 .delete_inode = sysfs_delete_inode,
Linus Torvalds1da177e2005-04-16 15:20:36 -070033};
34
Tejun Heo51225032007-06-14 04:27:25 +090035struct sysfs_dirent sysfs_root = {
Tejun Heodc2f75f2007-09-20 16:05:12 +090036 .s_name = "",
Tejun Heo13b30862007-06-14 03:45:14 +090037 .s_count = ATOMIC_INIT(1),
Tejun Heodc2f75f2007-09-20 16:05:12 +090038 .s_flags = SYSFS_DIR,
Tejun Heofc9f54b2007-06-14 03:45:17 +090039 .s_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
Eric Sandeendc351252007-06-11 14:02:45 +090040 .s_ino = 1,
Linus Torvalds1da177e2005-04-16 15:20:36 -070041};
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;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Tejun Heoe080e432007-07-18 14:29:06 +090054 /* get root inode, initialize and unlock it */
Eric W. Biederman4a67a1b2009-01-21 11:55:11 -080055 mutex_lock(&sysfs_mutex);
Eric W. Biedermanfac26222010-02-12 19:22:27 -080056 inode = sysfs_get_inode(sb, &sysfs_root);
Eric W. Biederman4a67a1b2009-01-21 11:55:11 -080057 mutex_unlock(&sysfs_mutex);
Tejun Heofc9f54b2007-06-14 03:45:17 +090058 if (!inode) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 pr_debug("sysfs: could not get root inode\n");
60 return -ENOMEM;
61 }
62
Tejun Heoe080e432007-07-18 14:29:06 +090063 /* instantiate and link root dentry */
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 root = d_alloc_root(inode);
65 if (!root) {
Harvey Harrison8e24eea2008-04-30 00:55:09 -070066 pr_debug("%s: could not get root dentry!\n",__func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 iput(inode);
68 return -ENOMEM;
69 }
70 root->d_fsdata = &sysfs_root;
71 sb->s_root = root;
72 return 0;
73}
74
David Howells454e2392006-06-23 02:02:57 -070075static int sysfs_get_sb(struct file_system_type *fs_type,
76 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -070077{
David Howells454e2392006-06-23 02:02:57 -070078 return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079}
80
81static struct file_system_type sysfs_fs_type = {
82 .name = "sysfs",
83 .get_sb = sysfs_get_sb,
Eric W. Biederman0333cd82007-08-20 21:36:29 +090084 .kill_sb = kill_anon_super,
Linus Torvalds1da177e2005-04-16 15:20:36 -070085};
86
87int __init sysfs_init(void)
88{
89 int err = -ENOMEM;
90
91 sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
92 sizeof(struct sysfs_dirent),
Paul Mundt20c2df82007-07-20 10:11:58 +090093 0, 0, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 if (!sysfs_dir_cachep)
95 goto out;
96
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -070097 err = sysfs_inode_init();
98 if (err)
99 goto out_err;
100
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 err = register_filesystem(&sysfs_fs_type);
102 if (!err) {
103 sysfs_mount = kern_mount(&sysfs_fs_type);
104 if (IS_ERR(sysfs_mount)) {
105 printk(KERN_ERR "sysfs: could not mount!\n");
106 err = PTR_ERR(sysfs_mount);
107 sysfs_mount = NULL;
108 unregister_filesystem(&sysfs_fs_type);
109 goto out_err;
110 }
111 } else
112 goto out_err;
113out:
114 return err;
115out_err:
116 kmem_cache_destroy(sysfs_dir_cachep);
117 sysfs_dir_cachep = NULL;
118 goto out;
119}
Neil Brownf1282c82008-07-16 08:58:04 +1000120
121#undef sysfs_get
122struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
123{
124 return __sysfs_get(sd);
125}
126EXPORT_SYMBOL_GPL(sysfs_get);
127
128#undef sysfs_put
129void sysfs_put(struct sysfs_dirent *sd)
130{
131 __sysfs_put(sd);
132}
133EXPORT_SYMBOL_GPL(sysfs_put);