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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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
22#include "sysfs.h"
23
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
Eric W. Biederman7d0c7d62007-08-20 21:36:30 +090025static struct vfsmount *sysfs_mount;
Linus Torvalds1da177e2005-04-16 15:20:36 -070026struct super_block * sysfs_sb = NULL;
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;
53 sysfs_sb = sb;
54
Tejun Heoe080e432007-07-18 14:29:06 +090055 /* get root inode, initialize and unlock it */
Eric W. Biederman4a67a1b2009-01-21 11:55:11 -080056 mutex_lock(&sysfs_mutex);
Tejun Heoe080e432007-07-18 14:29:06 +090057 inode = sysfs_get_inode(&sysfs_root);
Eric W. Biederman4a67a1b2009-01-21 11:55:11 -080058 mutex_unlock(&sysfs_mutex);
Tejun Heofc9f54b2007-06-14 03:45:17 +090059 if (!inode) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 pr_debug("sysfs: could not get root inode\n");
61 return -ENOMEM;
62 }
63
Tejun Heoe080e432007-07-18 14:29:06 +090064 /* instantiate and link root dentry */
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 root = d_alloc_root(inode);
66 if (!root) {
Harvey Harrison8e24eea2008-04-30 00:55:09 -070067 pr_debug("%s: could not get root dentry!\n",__func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 iput(inode);
69 return -ENOMEM;
70 }
71 root->d_fsdata = &sysfs_root;
72 sb->s_root = root;
73 return 0;
74}
75
David Howells454e2392006-06-23 02:02:57 -070076static int sysfs_get_sb(struct file_system_type *fs_type,
77 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
Linus Torvalds1da177e2005-04-16 15:20:36 -070078{
David Howells454e2392006-06-23 02:02:57 -070079 return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080}
81
82static struct file_system_type sysfs_fs_type = {
83 .name = "sysfs",
84 .get_sb = sysfs_get_sb,
Eric W. Biederman0333cd82007-08-20 21:36:29 +090085 .kill_sb = kill_anon_super,
Linus Torvalds1da177e2005-04-16 15:20:36 -070086};
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),
Paul Mundt20c2df82007-07-20 10:11:58 +090094 0, 0, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 if (!sysfs_dir_cachep)
96 goto out;
97
Peter Zijlstrae0bf68d2007-10-16 23:25:46 -070098 err = sysfs_inode_init();
99 if (err)
100 goto out_err;
101
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 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}
Neil Brownf1282c82008-07-16 08:58:04 +1000121
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);