文件系统学习-1

#include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/fs.h> #include <linux/device.h> #include <linux/cdev.h> #include <linux/major.h> #include <linux/vfs.h> #define ROMFS_MAGIC 0xEBAF3421 static struct kmem_cache *tbagfs_inode_cachep; struct tbagfs_inode_info {     struct inode vfs_inode;     unsigned long i_metasize; /* size of non-data area */     unsigned long i_dataoffset; /* from the start of fs */ }; /*  * * fill in the superblock  * */ static int tbagfs_fill_super(struct super_block *sb, void *data, int silent) {     return 0; } /*  * * get a superblock for mounting  * */ static int tbagfs_get_sb(struct file_system_type *fs_type,         int flags, const char *dev_name,         void *data, struct vfsmount *mnt) {     int ret = -EINVAL;     if (ret == -EINVAL)         ret = get_sb_bdev(fs_type, flags, dev_name, data,                 tbagfs_fill_super, mnt);     return ret; } static struct file_system_type tbagfs_fs_type = {     .owner = THIS_MODULE,     .name = "tbagfs",     .get_sb = tbagfs_get_sb,     .kill_sb = kill_block_super,     .fs_flags = FS_REQUIRES_DEV, }; static void tbagfs_i_init_once(void *_inode) {     struct tbagfs_inode_info *inode = _inode;     inode_init_once(&inode->vfs_inode); } static int __init init_tbagfs_fs(void) {     int ret = 0;     tbagfs_inode_cachep =         kmem_cache_create("tbagfs", sizeof(struct tbagfs_inode_info), 0,                 SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,                 tbagfs_i_init_once);     if(!tbagfs_inode_cachep){         printk(KERN_ERR "TBAGFS error: Failed to initialise inode cache\n");         return -ENOMEM;     }     ret = register_filesystem(&tbagfs_fs_type);     if(ret){         printk(KERN_ERR "TBAGFS error: Failed to register filesystem\n");         goto error_register;     }     return 0; error_register:     kmem_cache_destroy(tbagfs_inode_cachep);     return ret; } static void __exit exit_tbagfs_fs(void) {     unregister_filesystem(&tbagfs_fs_type);     kmem_cache_destroy(tbagfs_inode_cachep); } module_init(init_tbagfs_fs) module_exit(exit_tbagfs_fs) MODULE_LICENSE("GPL");