release/src-rt-6.x.4708/linux/linux-2.6.36/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, 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
  55 static 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
 120 static const struct vm_operations_struct nilfs_file_vm_ops = {
 121         .fault          = filemap_fault,
 122         .page_mkwrite   = nilfs_page_mkwrite,
 123 };
 124
 125 static 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  */
 137 const 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
 154 const 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 */