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1 | /* |
2 | * 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. |
11 | */ |
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> |
19 | #include <linux/module.h> |
20 | #include <linux/magic.h> |
21 | #include <linux/slab.h> |
22 | |
23 | #include "sysfs.h" |
24 | |
25 | |
26 | static struct vfsmount *sysfs_mount; |
27 | struct kmem_cache *sysfs_dir_cachep; |
28 | |
29 | static const struct super_operations sysfs_ops = { |
30 | .statfs = simple_statfs, |
31 | .drop_inode = generic_delete_inode, |
32 | .delete_inode = sysfs_delete_inode, |
33 | }; |
34 | |
35 | struct sysfs_dirent sysfs_root = { |
36 | .s_name = "", |
37 | .s_count = ATOMIC_INIT(1), |
38 | .s_flags = SYSFS_DIR, |
39 | .s_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, |
40 | .s_ino = 1, |
41 | }; |
42 | |
43 | static 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 | |
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); |
58 | if (!inode) { |
59 | pr_debug("sysfs: could not get root inode\n"); |
60 | return -ENOMEM; |
61 | } |
62 | |
63 | /* instantiate and link root dentry */ |
64 | root = d_alloc_root(inode); |
65 | if (!root) { |
66 | pr_debug("%s: could not get root dentry!\n",__func__); |
67 | iput(inode); |
68 | return -ENOMEM; |
69 | } |
70 | root->d_fsdata = &sysfs_root; |
71 | sb->s_root = root; |
72 | return 0; |
73 | } |
74 | |
75 | static int sysfs_get_sb(struct file_system_type *fs_type, |
76 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) |
77 | { |
78 | return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt); |
79 | } |
80 | |
81 | static struct file_system_type sysfs_fs_type = { |
82 | .name = "sysfs", |
83 | .get_sb = sysfs_get_sb, |
84 | .kill_sb = kill_anon_super, |
85 | }; |
86 | |
87 | int __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), |
93 | 0, 0, NULL); |
94 | if (!sysfs_dir_cachep) |
95 | goto out; |
96 | |
97 | err = sysfs_inode_init(); |
98 | if (err) |
99 | goto out_err; |
100 | |
101 | 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; |
113 | out: |
114 | return err; |
115 | out_err: |
116 | kmem_cache_destroy(sysfs_dir_cachep); |
117 | sysfs_dir_cachep = NULL; |
118 | goto out; |
119 | } |
120 | |
121 | #undef sysfs_get |
122 | struct sysfs_dirent *sysfs_get(struct sysfs_dirent *sd) |
123 | { |
124 | return __sysfs_get(sd); |
125 | } |
126 | EXPORT_SYMBOL_GPL(sysfs_get); |
127 | |
128 | #undef sysfs_put |
129 | void sysfs_put(struct sysfs_dirent *sd) |
130 | { |
131 | __sysfs_put(sd); |
132 | } |
133 | EXPORT_SYMBOL_GPL(sysfs_put); |
134 |
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