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 * Written by Amagai Yoshiji and Ryusuke Konishi.
  17 */
  18
  19#include <linux/fs.h>
  20#include <linux/mm.h>
  21#include <linux/writeback.h>
  22#include "nilfs.h"
  23#include "segment.h"
  24
  25int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
  26{
  27        /*
  28         * Called from fsync() system call
  29         * This is the only entry point that can catch write and synch
  30         * timing for both data blocks and intermediate blocks.
  31         *
  32         * This function should be implemented when the writeback function
  33         * will be implemented.
  34         */
  35        struct the_nilfs *nilfs;
  36        struct inode *inode = file->f_mapping->host;
  37        int err = 0;
  38
  39        if (nilfs_inode_dirty(inode)) {
  40                if (datasync)
  41                        err = nilfs_construct_dsync_segment(inode->i_sb, inode,
  42                                                            start, end);
  43                else
  44                        err = nilfs_construct_segment(inode->i_sb);
  45        }
  46
  47        nilfs = inode->i_sb->s_fs_info;
  48        if (!err)
  49                err = nilfs_flush_device(nilfs);
  50
  51        return err;
  52}
  53
  54static int nilfs_page_mkwrite(struct vm_fault *vmf)
  55{
  56        struct vm_area_struct *vma = vmf->vma;
  57        struct page *page = vmf->page;
  58        struct inode *inode = file_inode(vma->vm_file);
  59        struct nilfs_transaction_info ti;
  60        int ret = 0;
  61
  62        if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
  63                return VM_FAULT_SIGBUS; /* -ENOSPC */
  64
  65        sb_start_pagefault(inode->i_sb);
  66        lock_page(page);
  67        if (page->mapping != inode->i_mapping ||
  68            page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
  69                unlock_page(page);
  70                ret = -EFAULT;  /* make the VM retry the fault */
  71                goto out;
  72        }
  73
  74        /*
  75         * check to see if the page is mapped already (no holes)
  76         */
  77        if (PageMappedToDisk(page))
  78                goto mapped;
  79
  80        if (page_has_buffers(page)) {
  81                struct buffer_head *bh, *head;
  82                int fully_mapped = 1;
  83
  84                bh = head = page_buffers(page);
  85                do {
  86                        if (!buffer_mapped(bh)) {
  87                                fully_mapped = 0;
  88                                break;
  89                        }
  90                } while (bh = bh->b_this_page, bh != head);
  91
  92                if (fully_mapped) {
  93                        SetPageMappedToDisk(page);
  94                        goto mapped;
  95                }
  96        }
  97        unlock_page(page);
  98
  99        /*
 100         * fill hole blocks
 101         */
 102        ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
 103        /* never returns -ENOMEM, but may return -ENOSPC */
 104        if (unlikely(ret))
 105                goto out;
 106
 107        file_update_time(vma->vm_file);
 108        ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
 109        if (ret) {
 110                nilfs_transaction_abort(inode->i_sb);
 111                goto out;
 112        }
 113        nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
 114        nilfs_transaction_commit(inode->i_sb);
 115
 116 mapped:
 117        wait_for_stable_page(page);
 118 out:
 119        sb_end_pagefault(inode->i_sb);
 120        return block_page_mkwrite_return(ret);
 121}
 122
 123static const struct vm_operations_struct nilfs_file_vm_ops = {
 124        .fault          = filemap_fault,
 125        .map_pages      = filemap_map_pages,
 126        .page_mkwrite   = nilfs_page_mkwrite,
 127};
 128
 129static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 130{
 131        file_accessed(file);
 132        vma->vm_ops = &nilfs_file_vm_ops;
 133        return 0;
 134}
 135
 136/*
 137 * We have mostly NULL's here: the current defaults are ok for
 138 * the nilfs filesystem.
 139 */
 140const struct file_operations nilfs_file_operations = {
 141        .llseek         = generic_file_llseek,
 142        .read_iter      = generic_file_read_iter,
 143        .write_iter     = generic_file_write_iter,
 144        .unlocked_ioctl = nilfs_ioctl,
 145#ifdef CONFIG_COMPAT
 146        .compat_ioctl   = nilfs_compat_ioctl,
 147#endif  /* CONFIG_COMPAT */
 148        .mmap           = nilfs_file_mmap,
 149        .open           = generic_file_open,
 150        /* .release     = nilfs_release_file, */
 151        .fsync          = nilfs_sync_file,
 152        .splice_read    = generic_file_splice_read,
 153};
 154
 155const struct inode_operations nilfs_file_inode_operations = {
 156        .setattr        = nilfs_setattr,
 157        .permission     = nilfs_permission,
 158        .fiemap         = nilfs_fiemap,
 159};
 160
 161/* end of file */
 162