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 = 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
  59 static 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
 127 static 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
 133 static 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  */
 144 const 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
 159 const 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 */