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 20 #include "sysfs.h" 21 22 /* Random magic number */ 23 #define SYSFS_MAGIC 0x62656572 24 25 static struct vfsmount *sysfs_mount; 26 struct super_block * sysfs_sb = NULL; 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 }; 33 34 struct sysfs_dirent sysfs_root = { 35 .s_name = "", 36 .s_count = ATOMIC_INIT(1), 37 .s_flags = SYSFS_DIR, 38 .s_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, 39 .s_ino = 1, 40 }; 41 42 static int sysfs_fill_super(struct super_block *sb, void *data, int silent) 43 { 44 struct inode *inode; 45 struct dentry *root; 46 47 sb->s_blocksize = PAGE_CACHE_SIZE; 48 sb->s_blocksize_bits = PAGE_CACHE_SHIFT; 49 sb->s_magic = SYSFS_MAGIC; 50 sb->s_op = &sysfs_ops; 51 sb->s_time_gran = 1; 52 sysfs_sb = sb; 53 54 /* get root inode, initialize and unlock it */ 55 inode = sysfs_get_inode(&sysfs_root); 56 if (!inode) { 57 pr_debug("sysfs: could not get root inode\n"); 58 return -ENOMEM; 59 } 60 61 /* instantiate and link root dentry */ 62 root = d_alloc_root(inode); 63 if (!root) { 64 pr_debug("%s: could not get root dentry!\n",__FUNCTION__); 65 iput(inode); 66 return -ENOMEM; 67 } 68 root->d_fsdata = &sysfs_root; 69 sb->s_root = root; 70 return 0; 71 } 72 73 static int sysfs_get_sb(struct file_system_type *fs_type, 74 int flags, const char *dev_name, void *data, struct vfsmount *mnt) 75 { 76 return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt); 77 } 78 79 static struct file_system_type sysfs_fs_type = { 80 .name = "sysfs", 81 .get_sb = sysfs_get_sb, 82 .kill_sb = kill_anon_super, 83 }; 84 85 int __init sysfs_init(void) 86 { 87 int err = -ENOMEM; 88 89 sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache", 90 sizeof(struct sysfs_dirent), 91 0, 0, NULL); 92 if (!sysfs_dir_cachep) 93 goto out; 94 95 err = sysfs_inode_init(); 96 if (err) 97 goto out_err; 98 99 err = register_filesystem(&sysfs_fs_type); 100 if (!err) { 101 sysfs_mount = kern_mount(&sysfs_fs_type); 102 if (IS_ERR(sysfs_mount)) { 103 printk(KERN_ERR "sysfs: could not mount!\n"); 104 err = PTR_ERR(sysfs_mount); 105 sysfs_mount = NULL; 106 unregister_filesystem(&sysfs_fs_type); 107 goto out_err; 108 } 109 } else 110 goto out_err; 111 out: 112 return err; 113 out_err: 114 kmem_cache_destroy(sysfs_dir_cachep); 115 sysfs_dir_cachep = NULL; 116 goto out; 117 } 118