2 * fs/sysfs/symlink.c - operations for initializing and mounting sysfs
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
8 * This file is released under the GPLv2.
10 * Please see Documentation/filesystems/sysfs.txt for more information.
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 #include <linux/slab.h>
26 static struct vfsmount *sysfs_mnt;
27 struct kmem_cache *sysfs_dir_cachep;
29 static const struct super_operations sysfs_ops = {
30 .statfs = simple_statfs,
31 .drop_inode = generic_delete_inode,
32 .evict_inode = sysfs_evict_inode,
35 struct sysfs_dirent sysfs_root = {
37 .s_count = ATOMIC_INIT(1),
38 .s_flags = SYSFS_DIR | (KOBJ_NS_TYPE_NONE << SYSFS_NS_TYPE_SHIFT),
39 .s_mode = S_IFDIR | S_IRUGO | S_IXUGO,
43 static int sysfs_fill_super(struct super_block *sb, void *data, int silent)
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;
54 /* get root inode, initialize and unlock it */
55 mutex_lock(&sysfs_mutex);
56 inode = sysfs_get_inode(sb, &sysfs_root);
57 mutex_unlock(&sysfs_mutex);
59 pr_debug("sysfs: could not get root inode\n");
63 /* instantiate and link root dentry */
64 root = d_make_root(inode);
66 pr_debug("%s: could not get root dentry!\n",__func__);
69 root->d_fsdata = &sysfs_root;
74 static int sysfs_test_super(struct super_block *sb, void *data)
76 struct sysfs_super_info *sb_info = sysfs_info(sb);
77 struct sysfs_super_info *info = data;
78 enum kobj_ns_type type;
81 for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++) {
82 if (sb_info->ns[type] != info->ns[type])
88 static int sysfs_set_super(struct super_block *sb, void *data)
91 error = set_anon_super(sb, data);
97 static void free_sysfs_super_info(struct sysfs_super_info *info)
100 for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++)
101 kobj_ns_drop(type, info->ns[type]);
105 static struct dentry *sysfs_mount(struct file_system_type *fs_type,
106 int flags, const char *dev_name, void *data)
108 struct sysfs_super_info *info;
109 enum kobj_ns_type type;
110 struct super_block *sb;
113 info = kzalloc(sizeof(*info), GFP_KERNEL);
115 return ERR_PTR(-ENOMEM);
117 for (type = KOBJ_NS_TYPE_NONE; type < KOBJ_NS_TYPES; type++)
118 info->ns[type] = kobj_ns_grab_current(type);
120 sb = sget(fs_type, sysfs_test_super, sysfs_set_super, info);
121 if (IS_ERR(sb) || sb->s_fs_info != info)
122 free_sysfs_super_info(info);
127 error = sysfs_fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
129 deactivate_locked_super(sb);
130 return ERR_PTR(error);
132 sb->s_flags |= MS_ACTIVE;
135 return dget(sb->s_root);
138 static void sysfs_kill_sb(struct super_block *sb)
140 struct sysfs_super_info *info = sysfs_info(sb);
141 /* Remove the superblock from fs_supers/s_instances
142 * so we can't find it, before freeing sysfs_super_info.
145 free_sysfs_super_info(info);
148 static struct file_system_type sysfs_fs_type = {
150 .mount = sysfs_mount,
151 .kill_sb = sysfs_kill_sb,
154 int __init sysfs_init(void)
158 sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache",
159 sizeof(struct sysfs_dirent),
161 if (!sysfs_dir_cachep)
164 err = sysfs_inode_init();
168 err = register_filesystem(&sysfs_fs_type);
170 sysfs_mnt = kern_mount(&sysfs_fs_type);
171 if (IS_ERR(sysfs_mnt)) {
172 printk(KERN_ERR "sysfs: could not mount!\n");
173 err = PTR_ERR(sysfs_mnt);
175 unregister_filesystem(&sysfs_fs_type);
183 kmem_cache_destroy(sysfs_dir_cachep);
184 sysfs_dir_cachep = NULL;
189 struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd)
191 return __sysfs_get(sd);
193 EXPORT_SYMBOL_GPL(sysfs_get);
196 void sysfs_put(struct sysfs_dirent *sd)
200 EXPORT_SYMBOL_GPL(sysfs_put);