LXR linux/fs/nilfs2/file.c

   1/*
   2 * file.c - NILFS regular file handling primitives including fsync().
   3 *
   4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19 *
  20 * Written by Amagai Yoshiji <amagai@osrg.net>,
  21 *            Ryusuke Konishi <ryusuke@osrg.net>
  22 */
  23
  24#include <linux/fs.h>
  25#include <linux/mm.h>
  26#include <linux/writeback.h>
  27#include "nilfs.h"
  28#include "segment.h"
  29
  30int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
  31{
  32        /*
  33         * Called from fsync() system call
  34         * This is the only entry point that can catch write and synch
  35         * timing for both data blocks and intermediate blocks.
  36         *
  37         * This function should be implemented when the writeback function
  38         * will be implemented.
  39         */
  40        struct the_nilfs *nilfs;
  41        struct inode *inode = file->f_mapping->host;
  42        int err = 0;
  43
  44        if (nilfs_inode_dirty(inode)) {
  45                if (datasync)
  46                        err = nilfs_construct_dsync_segment(inode->i_sb, inode,
  47                                                            start, end);
  48                else
  49                        err = nilfs_construct_segment(inode->i_sb);
  50        }
  51
  52        nilfs = inode->i_sb->s_fs_info;
  53        if (!err)
  54                err = nilfs_flush_device(nilfs);
  55
  56        return err;
  57}
  58
  59static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
  60{
  61        struct page *page = vmf->page;
  62        struct inode *inode = file_inode(vma->vm_file);
  63        struct nilfs_transaction_info ti;
  64        int ret = 0;
  65
  66        if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
  67                return VM_FAULT_SIGBUS; /* -ENOSPC */
  68
  69        sb_start_pagefault(inode->i_sb);
  70        lock_page(page);
  71        if (page->mapping != inode->i_mapping ||
  72            page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
  73                unlock_page(page);
  74                ret = -EFAULT;  /* make the VM retry the fault */
  75                goto out;
  76        }
  77
  78        /*
  79         * check to see if the page is mapped already (no holes)
  80         */
  81        if (PageMappedToDisk(page))
  82                goto mapped;
  83
  84        if (page_has_buffers(page)) {
  85                struct buffer_head *bh, *head;
  86                int fully_mapped = 1;
  87
  88                bh = head = page_buffers(page);
  89                do {
  90                        if (!buffer_mapped(bh)) {
  91                                fully_mapped = 0;
  92                                break;
  93                        }
  94                } while (bh = bh->b_this_page, bh != head);
  95
  96                if (fully_mapped) {
  97                        SetPageMappedToDisk(page);
  98                        goto mapped;
  99                }
 100        }
 101        unlock_page(page);
 102
 103        /*
 104         * fill hole blocks
 105         */
 106        ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
 107        /* never returns -ENOMEM, but may return -ENOSPC */
 108        if (unlikely(ret))
 109                goto out;
 110
 111        file_update_time(vma->vm_file);
 112        ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
 113        if (ret) {
 114                nilfs_transaction_abort(inode->i_sb);
 115                goto out;
 116        }
 117        nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
 118        nilfs_transaction_commit(inode->i_sb);
 119
 120 mapped:
 121        wait_for_stable_page(page);
 122 out:
 123        sb_end_pagefault(inode->i_sb);
 124        return block_page_mkwrite_return(ret);
 125}
 126
 127static const struct vm_operations_struct nilfs_file_vm_ops = {
 128        .fault          = filemap_fault,
 129        .map_pages      = filemap_map_pages,
 130        .page_mkwrite   = nilfs_page_mkwrite,
 131};
 132
 133static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 134{
 135        file_accessed(file);
 136        vma->vm_ops = &nilfs_file_vm_ops;
 137        return 0;
 138}
 139
 140/*
 141 * We have mostly NULL's here: the current defaults are ok for
 142 * the nilfs filesystem.
 143 */
 144const struct file_operations nilfs_file_operations = {
 145        .llseek         = generic_file_llseek,
 146        .read_iter      = generic_file_read_iter,
 147        .write_iter     = generic_file_write_iter,
 148        .unlocked_ioctl = nilfs_ioctl,
 149#ifdef CONFIG_COMPAT
 150        .compat_ioctl   = nilfs_compat_ioctl,
 151#endif  /* CONFIG_COMPAT */
 152        .mmap           = nilfs_file_mmap,
 153        .open           = generic_file_open,
 154        /* .release     = nilfs_release_file, */
 155        .fsync          = nilfs_sync_file,
 156        .splice_read    = generic_file_splice_read,
 157};
 158
 159const struct inode_operations nilfs_file_inode_operations = {
 160        .setattr        = nilfs_setattr,
 161        .permission     = nilfs_permission,
 162        .fiemap         = nilfs_fiemap,
 163};
 164
 165/* end of file */
 166