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 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
  63 static 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
 126 static const struct vm_operations_struct nilfs_file_vm_ops = {
 127         .fault          = filemap_fault,
 128         .page_mkwrite   = nilfs_page_mkwrite,
 129 };
 130
 131 static 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  */
 143 const 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
 160 const 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 */