file.c
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/*
* 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 int 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 */
goto out;
}
/*
* check to see if the page is mapped already (no holes)
*/
if (PageMappedToDisk(page))
goto mapped;
if (page_has_buffers(page)) {
struct buffer_head *bh, *head;
int fully_mapped = 1;
bh = head = page_buffers(page);
do {
if (!buffer_mapped(bh)) {
fully_mapped = 0;
break;
}
} while (bh = bh->b_this_page, bh != head);
if (fully_mapped) {
SetPageMappedToDisk(page);
goto mapped;
}
}
unlock_page(page);
/*
* fill hole blocks
*/
ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
/* never returns -ENOMEM, but may return -ENOSPC */
if (unlikely(ret))
goto out;
file_update_time(vma->vm_file);
ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
if (ret) {
nilfs_transaction_abort(inode->i_sb);
goto out;
}
nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
nilfs_transaction_commit(inode->i_sb);
mapped:
wait_for_stable_page(page);
out:
sb_end_pagefault(inode->i_sb);
return block_page_mkwrite_return(ret);
}
static const struct vm_operations_struct nilfs_file_vm_ops = {
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = nilfs_page_mkwrite,
};
static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
{
file_accessed(file);
vma->vm_ops = &nilfs_file_vm_ops;
return 0;
}
/*
* We have mostly NULL's here: the current defaults are ok for
* the nilfs filesystem.
*/
const struct file_operations nilfs_file_operations = {
.llseek = generic_file_llseek,
.read_iter = generic_file_read_iter,
.write_iter = generic_file_write_iter,
.unlocked_ioctl = nilfs_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = nilfs_compat_ioctl,
#endif /* CONFIG_COMPAT */
.mmap = nilfs_file_mmap,
.open = generic_file_open,
/* .release = nilfs_release_file, */
.fsync = nilfs_sync_file,
.splice_read = generic_file_splice_read,
};
const struct inode_operations nilfs_file_inode_operations = {
.setattr = nilfs_setattr,
.permission = nilfs_permission,
.fiemap = nilfs_fiemap,
};
/* end of file */