kernel/inode.c

/*
    FUSE: Filesystem in Userspace
    Copyright (C) 2001  Miklos Szeredi (mszeredi@inf.bme.hu)

    This program can be distributed under the terms of the GNU GPL.
    See the file COPYING.
*/

#include "fuse_i.h"

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/file.h>

#define FUSE_SUPER_MAGIC 0x65735546

static void fuse_read_inode(struct inode *inode)
{
	/* No op */
}

static void send_forget(struct fuse_conn *fc, unsigned long *forget,
			unsigned int numforget)
{
	struct fuse_in in = FUSE_IN_INIT;
	
	in.h.opcode = FUSE_FORGET;
	in.h.ino = 0;
	in.argsize = numforget * sizeof(unsigned long);
	in.arg = forget;
	
	request_send(fc, &in, NULL);
}

static int alloc_cleared(struct fuse_conn *fc)
{
	unsigned long *tmp;
	
	spin_unlock(&fuse_lock);
	tmp = kmalloc(sizeof(unsigned long) * MAX_CLEARED, GFP_KERNEL);
	spin_lock(&fuse_lock);

	if(!fc->file || fc->cleared != NULL)
		kfree(tmp);
	else if(!tmp)
		printk("fuse_clear_inode: Cannot allocate memory\n");
	else
		fc->cleared = tmp;

	return fc->cleared != NULL;
}

static unsigned long *add_cleared(struct fuse_conn *fc, unsigned long ino)
{
	if(!fc->file || (!fc->cleared && !alloc_cleared(fc)))
		return NULL;

	fc->cleared[fc->numcleared] = ino;
	fc->numcleared ++;
	
	if(fc->numcleared == MAX_CLEARED) {
		unsigned long *tmp = fc->cleared;
		fc->cleared = NULL;
		fc->numcleared = 0;
		return tmp;
	}
	
	return NULL;
}

static void fuse_clear_inode(struct inode *inode)
{
	struct fuse_conn *fc = inode->i_sb->u.generic_sbp;
	unsigned long *forget;

	spin_lock(&fuse_lock);
	forget = add_cleared(fc, inode->i_ino);
	spin_unlock(&fuse_lock);

	if(forget) {
		send_forget(fc, forget, MAX_CLEARED);
		kfree(forget);
	}
}

static void fuse_put_super(struct super_block *sb)
{
	struct fuse_conn *fc = sb->u.generic_sbp;

	spin_lock(&fuse_lock);
	fc->sb = NULL;
	fuse_release_conn(fc);
	spin_unlock(&fuse_lock);

}

static struct super_operations fuse_super_operations = {
	read_inode:	fuse_read_inode,
	clear_inode:	fuse_clear_inode,
	put_super:	fuse_put_super,
};


static struct fuse_conn *get_conn(struct fuse_mount_data *d)
{
	struct fuse_conn *fc = NULL;
	struct file *file;
	struct inode *ino;

	if(d == NULL) {
		printk("fuse_read_super: Bad mount data\n");
		return NULL;
	}

	if(d->version != FUSE_MOUNT_VERSION) {
		printk("fuse_read_super: Bad mount version: %i\n", d->version);
		return NULL;
	}

	file = fget(d->fd);
	ino = NULL;
	if(file)
		ino = file->f_dentry->d_inode;
	
	if(!ino || ino->u.generic_ip != proc_fuse_dev) {
		printk("fuse_read_super: Bad file: %i\n", d->fd);
		goto out;
	}

	fc = file->private_data;

  out:
	fput(file);
	return fc;

}

static struct inode *get_root_inode(struct super_block *sb)
{
	struct inode *root;

	root = iget(sb, 1);
	if(root) {
		struct fuse_attr attr;
		memset(&attr, 0, sizeof(attr));
		attr.mode = S_IFDIR;
		fuse_init_inode(root, &attr);
	}

	return root;
}

static struct super_block *fuse_read_super(struct super_block *sb, 
					   void *data, int silent)
{	
	struct fuse_conn *fc;
	struct inode *root;

        sb->s_blocksize = 1024;
        sb->s_blocksize_bits = 10;
        sb->s_magic = FUSE_SUPER_MAGIC;
        sb->s_op = &fuse_super_operations;

	root = get_root_inode(sb);
	if(root == NULL) {
		printk("fuse_read_super: failed to get root inode\n");
		return NULL;
	}

	spin_lock(&fuse_lock);
	fc = get_conn(data);
	if(fc == NULL)
		goto err;

	if(fc->sb != NULL) {
		printk("fuse_read_super: connection %i already mounted\n",
		       fc->id);
		goto err;
	}

        sb->u.generic_sbp = fc;
	sb->s_root = d_alloc_root(root);
	fc->sb = sb;
	spin_unlock(&fuse_lock);
	
	return sb;

  err:
	spin_unlock(&fuse_lock);
	iput(root);
	return NULL;
}


static DECLARE_FSTYPE(fuse_fs_type, "fuse", fuse_read_super, 0);

int fuse_fs_init()
{
	int res;

	res = register_filesystem(&fuse_fs_type);
	if(res)
		printk("fuse: failed to register filesystem\n");

	return res;
}

void fuse_fs_cleanup()
{
	unregister_filesystem(&fuse_fs_type);
}

/* 
 * Local Variables:
 * indent-tabs-mode: t
 * c-basic-offset: 8
 * End:
 */