inode.c

linux下的用户文件系统fuse-2.5.2

				return 0;
			d->user_id = value;
			d->user_id_present = 1;
			break;

		case OPT_GROUP_ID:
			if (match_int(&args[0], &value))
				return 0;
			d->group_id = value;
			d->group_id_present = 1;
			break;

		case OPT_DEFAULT_PERMISSIONS:
			d->flags |= FUSE_DEFAULT_PERMISSIONS;
			break;

		case OPT_ALLOW_OTHER:
			d->flags |= FUSE_ALLOW_OTHER;
			break;

#ifndef KERNEL_2_6
		case OPT_LARGE_READ:
			d->flags |= FUSE_LARGE_READ;
			break;
#endif
		case OPT_MAX_READ:
			if (match_int(&args[0], &value))
				return 0;
			d->max_read = value;
			break;

		default:
			return 0;
		}
	}

	if (!d->fd_present || !d->rootmode_present ||
	    !d->user_id_present || !d->group_id_present)
		return 0;

	return 1;
}

static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
{
	struct fuse_conn *fc = get_fuse_conn_super(mnt->mnt_sb);

	seq_printf(m, ",user_id=%u", fc->user_id);
	seq_printf(m, ",group_id=%u", fc->group_id);
	if (fc->flags & FUSE_DEFAULT_PERMISSIONS)
		seq_puts(m, ",default_permissions");
	if (fc->flags & FUSE_ALLOW_OTHER)
		seq_puts(m, ",allow_other");
#ifndef KERNEL_2_6
	if (fc->flags & FUSE_LARGE_READ)
		seq_puts(m, ",large_read");
#endif
	if (fc->max_read != ~0)
		seq_printf(m, ",max_read=%u", fc->max_read);
	return 0;
}

static void free_conn(struct fuse_conn *fc)
{
	while (!list_empty(&fc->unused_list)) {
		struct fuse_req *req;
		req = list_entry(fc->unused_list.next, struct fuse_req, list);
		list_del(&req->list);
		fuse_request_free(req);
	}
	kfree(fc);
}

/* Must be called with the fuse lock held */
void fuse_release_conn(struct fuse_conn *fc)
{
	fc->count--;
	if (!fc->count)
		free_conn(fc);
}

static struct fuse_conn *new_conn(void)
{
	struct fuse_conn *fc;

	fc = kmalloc(sizeof(*fc), GFP_KERNEL);
	if (fc != NULL) {
		int i;
		memset(fc, 0, sizeof(*fc));
		init_waitqueue_head(&fc->waitq);
		INIT_LIST_HEAD(&fc->pending);
		INIT_LIST_HEAD(&fc->processing);
		INIT_LIST_HEAD(&fc->unused_list);
		INIT_LIST_HEAD(&fc->background);
		sema_init(&fc->outstanding_sem, 0);
		init_rwsem(&fc->sbput_sem);
		for (i = 0; i < FUSE_MAX_OUTSTANDING; i++) {
			struct fuse_req *req = fuse_request_alloc();
			if (!req) {
				free_conn(fc);
				return NULL;
			}
			list_add(&req->list, &fc->unused_list);
		}
#ifdef KERNEL_2_6_6_PLUS
		fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
		fc->bdi.unplug_io_fn = default_unplug_io_fn;
#endif
		fc->reqctr = 0;
	}
	return fc;
}

static struct fuse_conn *get_conn(struct file *file, struct super_block *sb)
{
	struct fuse_conn *fc;

	if (file->f_op != &fuse_dev_operations)
		return ERR_PTR(-EINVAL);
	fc = new_conn();
	if (fc == NULL)
		return ERR_PTR(-ENOMEM);
	spin_lock(&fuse_lock);
	if (file->private_data) {
		free_conn(fc);
		fc = ERR_PTR(-EINVAL);
	} else {
		file->private_data = fc;
		*get_fuse_conn_super_p(sb) = fc;
		fc->mounted = 1;
		fc->connected = 1;
		fc->count = 2;
	}
	spin_unlock(&fuse_lock);
	return fc;
}

static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
{
	struct fuse_attr attr;
	memset(&attr, 0, sizeof(attr));

	attr.mode = mode;
	attr.ino = FUSE_ROOT_ID;
	return fuse_iget(sb, 1, 0, &attr);
}
#ifndef FUSE_MAINLINE
#ifdef KERNEL_2_6
static struct dentry *fuse_get_dentry(struct super_block *sb, void *vobjp)
{
	__u32 *objp = vobjp;
	unsigned long nodeid = objp[0];
	__u32 generation = objp[1];
	struct inode *inode;
	struct dentry *entry;

	if (nodeid == 0)
		return ERR_PTR(-ESTALE);

	inode = ilookup5(sb, nodeid, fuse_inode_eq, &nodeid);
	if (!inode)
		return ERR_PTR(-ESTALE);
	if (inode->i_generation != generation) {
		iput(inode);
		return ERR_PTR(-ESTALE);
	}

	entry = d_alloc_anon(inode);
	if (!entry) {
		iput(inode);
		return ERR_PTR(-ENOMEM);
	}

	return entry;
}

static int fuse_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len,
			  int connectable)
{
	struct inode *inode = dentry->d_inode;
	int len = *max_len;
	int type = 1;

	if (len < 2 || (connectable && len < 4))
		return 255;

	len = 2;
	fh[0] = get_fuse_inode(inode)->nodeid;
	fh[1] = inode->i_generation;
	if (connectable && !S_ISDIR(inode->i_mode)) {
		struct inode *parent;

		spin_lock(&dentry->d_lock);
		parent = dentry->d_parent->d_inode;
		fh[2] = get_fuse_inode(parent)->nodeid;
		fh[3] = parent->i_generation;
		spin_unlock(&dentry->d_lock);
		len = 4;
		type = 2;
	}
	*max_len = len;
	return type;
}

static struct export_operations fuse_export_operations = {
	.get_dentry	= fuse_get_dentry,
	.encode_fh      = fuse_encode_fh,
};
#endif
#endif

static struct super_operations fuse_super_operations = {
	.alloc_inode    = fuse_alloc_inode,
	.destroy_inode  = fuse_destroy_inode,
	.read_inode	= fuse_read_inode,
	.clear_inode	= fuse_clear_inode,
	.put_super	= fuse_put_super,
	.statfs		= fuse_statfs,
	.show_options	= fuse_show_options,
};

static int fuse_fill_super(struct super_block *sb, void *data, int silent)
{
	struct fuse_conn *fc;
	struct inode *root;
	struct fuse_mount_data d;
	struct file *file;
	int err;

	if (!parse_fuse_opt((char *) data, &d))
		return -EINVAL;

	sb->s_blocksize = PAGE_CACHE_SIZE;
	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
	sb->s_magic = FUSE_SUPER_MAGIC;
	sb->s_op = &fuse_super_operations;
	sb->s_maxbytes = MAX_LFS_FILESIZE;
#ifndef FUSE_MAINLINE
#ifdef KERNEL_2_6
	sb->s_export_op = &fuse_export_operations;
#endif
#endif

	file = fget(d.fd);
	if (!file)
		return -EINVAL;

	fc = get_conn(file, sb);
	fput(file);
	if (IS_ERR(fc))
		return PTR_ERR(fc);

	fc->flags = d.flags;
	fc->user_id = d.user_id;
	fc->group_id = d.group_id;
	fc->max_read = d.max_read;
#ifdef KERNEL_2_6
	if (fc->max_read / PAGE_CACHE_SIZE < fc->bdi.ra_pages)
		fc->bdi.ra_pages = fc->max_read / PAGE_CACHE_SIZE;
#endif

	err = -ENOMEM;
	root = get_root_inode(sb, d.rootmode);
	if (root == NULL)
		goto err;

	sb->s_root = d_alloc_root(root);
	if (!sb->s_root) {
		iput(root);
		goto err;
	}
	fuse_send_init(fc);
	return 0;

 err:
	spin_lock(&fuse_lock);
	fuse_release_conn(fc);
	spin_unlock(&fuse_lock);
	return err;
}

#ifdef KERNEL_2_6
static struct super_block *fuse_get_sb(struct file_system_type *fs_type,
				       int flags, const char *dev_name,
				       void *raw_data)
{
	return get_sb_nodev(fs_type, flags, raw_data, fuse_fill_super);
}

static struct file_system_type fuse_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "fuse",
	.get_sb		= fuse_get_sb,
	.kill_sb	= kill_anon_super,
};
#else
static struct super_block *fuse_read_super_compat(struct super_block *sb,
						  void *data, int silent)
{
	int err = fuse_fill_super(sb, data, silent);
	if (err)
		return NULL;
	else
		return sb;
}

static DECLARE_FSTYPE(fuse_fs_type, "fuse", fuse_read_super_compat, 0);
#endif

static void fuse_inode_init_once(void *foo, kmem_cache_t *cachep,
				 unsigned long flags)
{
	struct inode * inode = foo;

	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
	    SLAB_CTOR_CONSTRUCTOR)
		inode_init_once(inode);
}

static int __init fuse_fs_init(void)
{
	int err;

	err = register_filesystem(&fuse_fs_type);
	if (err)
		printk("fuse: failed to register filesystem\n");
	else {
		fuse_inode_cachep = kmem_cache_create("fuse_inode",
						      sizeof(struct fuse_inode),
						      0, SLAB_HWCACHE_ALIGN,
						      fuse_inode_init_once, NULL);
		if (!fuse_inode_cachep) {
			unregister_filesystem(&fuse_fs_type);
			err = -ENOMEM;
		}
	}

	return err;
}

static void fuse_fs_cleanup(void)
{
	unregister_filesystem(&fuse_fs_type);
	kmem_cache_destroy(fuse_inode_cachep);
}

static int __init fuse_init(void)
{
	int res;

	printk("fuse init (API version %i.%i)\n",
	       FUSE_KERNEL_VERSION, FUSE_KERNEL_MINOR_VERSION);
#ifndef FUSE_MAINLINE
	printk("fuse distribution version: %s\n", FUSE_VERSION);
#endif

	spin_lock_init(&fuse_lock);
	res = fuse_fs_init();
	if (res)
		goto err;

	res = fuse_dev_init();
	if (res)
		goto err_fs_cleanup;

	return 0;

 err_fs_cleanup:
	fuse_fs_cleanup();
 err:
	return res;
}

static void __exit fuse_exit(void)
{
	printk(KERN_DEBUG "fuse exit\n");

	fuse_fs_cleanup();
	fuse_dev_cleanup();
}

module_init(fuse_init);
module_exit(fuse_exit);