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, 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        if (!nilfs_inode_dirty(inode))
  44                return 0;
  45
  46        if (datasync)
  47                err = nilfs_construct_dsync_segment(inode->i_sb, inode, 0,
  48                                                    LLONG_MAX);
  49        else
  50                err = nilfs_construct_segment(inode->i_sb);
  51
  52        return err;
  53}
  54
  55static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
  56{
  57        struct page *page = vmf->page;
  58        struct inode *inode = vma->vm_file->f_dentry->d_inode;
  59        struct nilfs_transaction_info ti;
  60        int ret;
  61
  62        if (unlikely(nilfs_near_disk_full(NILFS_SB(inode->i_sb)->s_nilfs)))
  63                return VM_FAULT_SIGBUS; /* -ENOSPC */
  64
  65        lock_page(page);
  66        if (page->mapping != inode->i_mapping ||
  67            page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
  68                unlock_page(page);
  69                return VM_FAULT_NOPAGE; /* make the VM retry the fault */
  70        }
  71
  72        /*
  73         * check to see if the page is mapped already (no holes)
  74         */
  75        if (PageMappedToDisk(page)) {
  76                unlock_page(page);
  77                goto mapped;
  78        }
  79        if (page_has_buffers(page)) {
  80                struct buffer_head *bh, *head;
  81                int fully_mapped = 1;
  82
  83                bh = head = page_buffers(page);
  84                do {
  85                        if (!buffer_mapped(bh)) {
  86                                fully_mapped = 0;
  87                                break;
  88                        }
  89                } while (bh = bh->b_this_page, bh != head);
  90
  91                if (fully_mapped) {
  92                        SetPageMappedToDisk(page);
  93                        unlock_page(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                return VM_FAULT_SIGBUS;
 106
 107        ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
 108        if (unlikely(ret)) {
 109                nilfs_transaction_abort(inode->i_sb);
 110                return ret;
 111        }
 112        nilfs_transaction_commit(inode->i_sb);
 113
 114 mapped:
 115        SetPageChecked(page);
 116        wait_on_page_writeback(page);
 117        return 0;
 118}
 119
 120static const struct vm_operations_struct nilfs_file_vm_ops = {
 121        .fault          = filemap_fault,
 122        .page_mkwrite   = nilfs_page_mkwrite,
 123};
 124
 125static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 126{
 127        file_accessed(file);
 128        vma->vm_ops = &nilfs_file_vm_ops;
 129        vma->vm_flags |= VM_CAN_NONLINEAR;
 130        return 0;
 131}
 132
 133/*
 134 * We have mostly NULL's here: the current defaults are ok for
 135 * the nilfs filesystem.
 136 */
 137const struct file_operations nilfs_file_operations = {
 138        .llseek         = generic_file_llseek,
 139        .read           = do_sync_read,
 140        .write          = do_sync_write,
 141        .aio_read       = generic_file_aio_read,
 142        .aio_write      = generic_file_aio_write,
 143        .unlocked_ioctl = nilfs_ioctl,
 144#ifdef CONFIG_COMPAT
 145        .compat_ioctl   = nilfs_ioctl,
 146#endif  /* CONFIG_COMPAT */
 147        .mmap           = nilfs_file_mmap,
 148        .open           = generic_file_open,
 149        /* .release     = nilfs_release_file, */
 150        .fsync          = nilfs_sync_file,
 151        .splice_read    = generic_file_splice_read,
 152};
 153
 154const struct inode_operations nilfs_file_inode_operations = {
 155        .truncate       = nilfs_truncate,
 156        .setattr        = nilfs_setattr,
 157        .permission     = nilfs_permission,
 158};
 159
 160/* end of file */
 161