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
  30 int 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;
  43
  44         err = filemap_write_and_wait_range(inode->i_mapping, start, end);
  45         if (err)
  46                 return err;
  47         mutex_lock(&inode->i_mutex);
  48
  49         if (nilfs_inode_dirty(inode)) {
  50                 if (datasync)
  51                         err = nilfs_construct_dsync_segment(inode->i_sb, inode,
  52                                                             0, LLONG_MAX);
  53                 else
  54                         err = nilfs_construct_segment(inode->i_sb);
  55         }
  56         mutex_unlock(&inode->i_mutex);
  57
  58         nilfs = inode->i_sb->s_fs_info;
  59         if (!err && nilfs_test_opt(nilfs, BARRIER)) {
  60                 err = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL);
  61                 if (err != -EIO)
  62                         err = 0;
  63         }
  64         return err;
  65 }
  66
  67 static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
  68 {
  69         struct page *page = vmf->page;
  70         struct inode *inode = file_inode(vma->vm_file);
  71         struct nilfs_transaction_info ti;
  72         int ret = 0;
  73
  74         if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
  75                 return VM_FAULT_SIGBUS; /* -ENOSPC */
  76
  77         sb_start_pagefault(inode->i_sb);
  78         lock_page(page);
  79         if (page->mapping != inode->i_mapping ||
  80             page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
  81                 unlock_page(page);
  82                 ret = -EFAULT;  /* make the VM retry the fault */
  83                 goto out;
  84         }
  85
  86         /*
  87          * check to see if the page is mapped already (no holes)
  88          */
  89         if (PageMappedToDisk(page))
  90                 goto mapped;
  91
  92         if (page_has_buffers(page)) {
  93                 struct buffer_head *bh, *head;
  94                 int fully_mapped = 1;
  95
  96                 bh = head = page_buffers(page);
  97                 do {
  98                         if (!buffer_mapped(bh)) {
  99                                 fully_mapped = 0;
 100                                 break;
 101                         }
 102                 } while (bh = bh->b_this_page, bh != head);
 103
 104                 if (fully_mapped) {
 105                         SetPageMappedToDisk(page);
 106                         goto mapped;
 107                 }
 108         }
 109         unlock_page(page);
 110
 111         /*
 112          * fill hole blocks
 113          */
 114         ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
 115         /* never returns -ENOMEM, but may return -ENOSPC */
 116         if (unlikely(ret))
 117                 goto out;
 118
 119         file_update_time(vma->vm_file);
 120         ret = __block_page_mkwrite(vma, vmf, nilfs_get_block);
 121         if (ret) {
 122                 nilfs_transaction_abort(inode->i_sb);
 123                 goto out;
 124         }
 125         nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
 126         nilfs_transaction_commit(inode->i_sb);
 127
 128  mapped:
 129         wait_on_page_writeback(page);
 130  out:
 131         sb_end_pagefault(inode->i_sb);
 132         return block_page_mkwrite_return(ret);
 133 }
 134
 135 static const struct vm_operations_struct nilfs_file_vm_ops = {
 136         .fault          = filemap_fault,
 137         .page_mkwrite   = nilfs_page_mkwrite,
 138         .remap_pages    = generic_file_remap_pages,
 139 };
 140
 141 static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 142 {
 143         file_accessed(file);
 144         vma->vm_ops = &nilfs_file_vm_ops;
 145         return 0;
 146 }
 147
 148 /*
 149  * We have mostly NULL's here: the current defaults are ok for
 150  * the nilfs filesystem.
 151  */
 152 const struct file_operations nilfs_file_operations = {
 153         .llseek         = generic_file_llseek,
 154         .read           = do_sync_read,
 155         .write          = do_sync_write,
 156         .aio_read       = generic_file_aio_read,
 157         .aio_write      = generic_file_aio_write,
 158         .unlocked_ioctl = nilfs_ioctl,
 159 #ifdef CONFIG_COMPAT
 160         .compat_ioctl   = nilfs_compat_ioctl,
 161 #endif  /* CONFIG_COMPAT */
 162         .mmap           = nilfs_file_mmap,
 163         .open           = generic_file_open,
 164         /* .release     = nilfs_release_file, */
 165         .fsync          = nilfs_sync_file,
 166         .splice_read    = generic_file_splice_read,
 167 };
 168
 169 const struct inode_operations nilfs_file_inode_operations = {
 170         .setattr        = nilfs_setattr,
 171         .permission     = nilfs_permission,
 172         .fiemap         = nilfs_fiemap,
 173 };
 174
 175 /* end of file */