/* * mount.c - operations for initializing and mounting sysfs. */ #define DEBUG #include <linux/fs.h> #include <linux/mount.h> #include <linux/pagemap.h> #include <linux/init.h> #include "sysfs.h" /* Random magic number */ #define SYSFS_MAGIC 0x62656572 struct vfsmount *sysfs_mount; struct super_block * sysfs_sb = NULL; kmem_cache_t *sysfs_dir_cachep; static struct super_operations sysfs_ops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, }; static struct sysfs_dirent sysfs_root = { .s_sibling = LIST_HEAD_INIT(sysfs_root.s_sibling), .s_children = LIST_HEAD_INIT(sysfs_root.s_children), .s_element = NULL, .s_type = SYSFS_ROOT, .s_iattr = NULL, }; static int sysfs_fill_super(struct super_block *sb, void *data, int silent) { struct inode *inode; struct dentry *root; sb->s_blocksize = PAGE_CACHE_SIZE; sb->s_blocksize_bits = PAGE_CACHE_SHIFT; sb->s_magic = SYSFS_MAGIC; sb->s_op = &sysfs_ops; sb->s_time_gran = 1; sysfs_sb = sb; inode = sysfs_new_inode(S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, &sysfs_root); if (inode) { inode->i_op = &sysfs_dir_inode_operations; inode->i_fop = &sysfs_dir_operations; /* directory inodes start off with i_nlink == 2 (for "." entry) */ inc_nlink(inode); } else { pr_debug("sysfs: could not get root inode\n"); return -ENOMEM; } root = d_alloc_root(inode); if (!root) { pr_debug("%s: could not get root dentry!\n",__FUNCTION__); iput(inode); return -ENOMEM; } root->d_fsdata = &sysfs_root; sb->s_root = root; return 0; } static int sysfs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { return get_sb_single(fs_type, flags, data, sysfs_fill_super, mnt); } static struct file_system_type sysfs_fs_type = { .name = "sysfs", .get_sb = sysfs_get_sb, .kill_sb = kill_litter_super, }; int __init sysfs_init(void) { int err = -ENOMEM; sysfs_dir_cachep = kmem_cache_create("sysfs_dir_cache", sizeof(struct sysfs_dirent), 0, 0, NULL, NULL); if (!sysfs_dir_cachep) goto out; err = register_filesystem(&sysfs_fs_type); if (!err) { sysfs_mount = kern_mount(&sysfs_fs_type); if (IS_ERR(sysfs_mount)) { printk(KERN_ERR "sysfs: could not mount!\n"); err = PTR_ERR(sysfs_mount); sysfs_mount = NULL; unregister_filesystem(&sysfs_fs_type); goto out_err; } } else goto out_err; out: return err; out_err: kmem_cache_destroy(sysfs_dir_cachep); sysfs_dir_cachep = NULL; goto out; }