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 inode *inode = file->f_mapping->host;
  41        int err;
  42
  43        err = filemap_write_and_wait_range(inode->i_mapping, start, end);
  44        if (err)
  45                return err;
  46        mutex_lock(&inode->i_mutex);
  47
  48        if (!nilfs_inode_dirty(inode)) {
  49                mutex_unlock(&inode->i_mutex);
  50                return 0;
  51        }
  52
  53        if (datasync)
  54                err = nilfs_construct_dsync_segment(inode->i_sb, inode, 0,
  55                                                    LLONG_MAX);
  56        else
  57                err = nilfs_construct_segment(inode->i_sb);
  58
  59        mutex_unlock(&inode->i_mutex);
  60        return err;
  61}
  62
  63static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
  64{
  65        struct page *page = vmf->page;
  66        struct inode *inode = vma->vm_file->f_dentry->d_inode;
  67        struct nilfs_transaction_info ti;
  68        int ret;
  69
  70        if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
  71                return VM_FAULT_SIGBUS; /* -ENOSPC */
  72
  73        lock_page(page);
  74        if (page->mapping != inode->i_mapping ||
  75            page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
  76                unlock_page(page);
  77                return VM_FAULT_NOPAGE; /* make the VM retry the fault */
  78        }
  79
  80        /*
  81         * check to see if the page is mapped already (no holes)
  82         */
  83        if (PageMappedToDisk(page))
  84                goto mapped;
  85
  86        if (page_has_buffers(page)) {
  87                struct buffer_head *bh, *head;
  88                int fully_mapped = 1;
  89
  90                bh = head = page_buffers(page);
  91                do {
  92                        if (!buffer_mapped(bh)) {
  93                                fully_mapped = 0;
  94                                break;
  95                        }
  96                } while (bh = bh->b_this_page, bh != head);
  97
  98                if (fully_mapped) {
  99                        SetPageMappedToDisk(page);
 100                        goto mapped;
 101                }
 102        }
 103        unlock_page(page);
 104
 105        /*
 106         * fill hole blocks
 107         */
 108        ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
 109        /* never returns -ENOMEM, but may return -ENOSPC */
 110        if (unlikely(ret))
 111                return VM_FAULT_SIGBUS;
 112
 113        ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
 114        if (ret != VM_FAULT_LOCKED) {
 115                nilfs_transaction_abort(inode->i_sb);
 116                return ret;
 117        }
 118        nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
 119        nilfs_transaction_commit(inode->i_sb);
 120
 121 mapped:
 122        wait_on_page_writeback(page);
 123        return VM_FAULT_LOCKED;
 124}
 125
 126static const struct vm_operations_struct nilfs_file_vm_ops = {
 127        .fault          = filemap_fault,
 128        .page_mkwrite   = nilfs_page_mkwrite,
 129};
 130
 131static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 132{
 133        file_accessed(file);
 134        vma->vm_ops = &nilfs_file_vm_ops;
 135        vma->vm_flags |= VM_CAN_NONLINEAR;
 136        return 0;
 137}
 138
 139/*
 140 * We have mostly NULL's here: the current defaults are ok for
 141 * the nilfs filesystem.
 142 */
 143const struct file_operations nilfs_file_operations = {
 144        .llseek         = generic_file_llseek,
 145        .read           = do_sync_read,
 146        .write          = do_sync_write,
 147        .aio_read       = generic_file_aio_read,
 148        .aio_write      = generic_file_aio_write,
 149        .unlocked_ioctl = nilfs_ioctl,
 150#ifdef CONFIG_COMPAT
 151        .compat_ioctl   = nilfs_compat_ioctl,
 152#endif  /* CONFIG_COMPAT */
 153        .mmap           = nilfs_file_mmap,
 154        .open           = generic_file_open,
 155        /* .release     = nilfs_release_file, */
 156        .fsync          = nilfs_sync_file,
 157        .splice_read    = generic_file_splice_read,
 158};
 159
 160const struct inode_operations nilfs_file_inode_operations = {
 161        .truncate       = nilfs_truncate,
 162        .setattr        = nilfs_setattr,
 163        .permission     = nilfs_permission,
 164        .fiemap         = nilfs_fiemap,
 165};
 166
 167/* end of file */
 168