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
  25 int 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
  54 static 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
 123 static 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
 129 static 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  */
 140 const 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
 155 const 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 */