file.c

/*
 * file.c - NILFS regular file handling primitives including fsync().
 *
 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * Written by Amagai Yoshiji and Ryusuke Konishi.
 */

#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/writeback.h>
#include "nilfs.h"
#include "segment.h"

int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
{
	/*
	 * Called from fsync() system call
	 * This is the only entry point that can catch write and synch
	 * timing for both data blocks and intermediate blocks.
	 *
	 * This function should be implemented when the writeback function
	 * will be implemented.
	 */
	struct the_nilfs *nilfs;
	struct inode *inode = file->f_mapping->host;
	int err = 0;

	if (nilfs_inode_dirty(inode)) {
		if (datasync)
			err = nilfs_construct_dsync_segment(inode->i_sb, inode,
							    start, end);
		else
			err = nilfs_construct_segment(inode->i_sb);
	}

	nilfs = inode->i_sb->s_fs_info;
	if (!err)
		err = nilfs_flush_device(nilfs);

	return err;
}

static vm_fault_t nilfs_page_mkwrite(struct vm_fault *vmf)
{
	struct vm_area_struct *vma = vmf->vma;
	struct page *page = vmf->page;
	struct inode *inode = file_inode(vma->vm_file);
	struct nilfs_transaction_info ti;
	int ret = 0;

	if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
		return VM_FAULT_SIGBUS; /* -ENOSPC */

	sb_start_pagefault(inode->i_sb);
	lock_page(page);
	if (page->mapping != inode->i_mapping ||
	    page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
		unlock_page(page);
		ret = -EFAULT;	/* make the VM retry the fault */