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   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, struct dentry *dentry, 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 = dentry->d_inode;
  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);
  48         else
  49                 err = nilfs_construct_segment(inode->i_sb);
  50
  51         return err;
  52 }
  53
  54 static ssize_t
  55 nilfs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
  56                      unsigned long nr_segs, loff_t pos)
  57 {
  58         struct file *file = iocb->ki_filp;
  59         struct inode *inode = file->f_dentry->d_inode;
  60         ssize_t ret;
  61
  62         ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
  63         if (ret <= 0)
  64                 return ret;
  65
  66         if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
  67                 int err;
  68
  69                 err = nilfs_construct_dsync_segment(inode->i_sb, inode);
  70                 if (unlikely(err))
  71                         return err;
  72         }
  73         return ret;
  74 }
  75
  76 static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
  77 {
  78         struct page *page = vmf->page;
  79         struct inode *inode = vma->vm_file->f_dentry->d_inode;
  80         struct nilfs_transaction_info ti;
  81         int ret;
  82
  83         if (unlikely(nilfs_near_disk_full(NILFS_SB(inode->i_sb)->s_nilfs)))
  84                 return VM_FAULT_SIGBUS; /* -ENOSPC */
  85
  86         lock_page(page);
  87         if (page->mapping != inode->i_mapping ||
  88             page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
  89                 unlock_page(page);
  90                 return VM_FAULT_NOPAGE; /* make the VM retry the fault */
  91         }
  92
  93         /*
  94          * check to see if the page is mapped already (no holes)
  95          */
  96         if (PageMappedToDisk(page)) {
  97                 unlock_page(page);
  98                 goto mapped;
  99         }
 100         if (page_has_buffers(page)) {
 101                 struct buffer_head *bh, *head;
 102                 int fully_mapped = 1;
 103
 104                 bh = head = page_buffers(page);
 105                 do {
 106                         if (!buffer_mapped(bh)) {
 107                                 fully_mapped = 0;
 108                                 break;
 109                         }
 110                 } while (bh = bh->b_this_page, bh != head);
 111
 112                 if (fully_mapped) {
 113                         SetPageMappedToDisk(page);
 114                         unlock_page(page);
 115                         goto mapped;
 116                 }
 117         }
 118         unlock_page(page);
 119
 120         /*
 121          * fill hole blocks
 122          */
 123         ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
 124         /* never returns -ENOMEM, but may return -ENOSPC */
 125         if (unlikely(ret))
 126                 return VM_FAULT_SIGBUS;
 127
 128         ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
 129         if (unlikely(ret)) {
 130                 nilfs_transaction_abort(inode->i_sb);
 131                 return ret;
 132         }
 133         nilfs_transaction_commit(inode->i_sb);
 134
 135  mapped:
 136         SetPageChecked(page);
 137         wait_on_page_writeback(page);
 138         return 0;
 139 }
 140
 141 struct vm_operations_struct nilfs_file_vm_ops = {
 142         .fault          = filemap_fault,
 143         .page_mkwrite   = nilfs_page_mkwrite,
 144 };
 145
 146 static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 147 {
 148         file_accessed(file);
 149         vma->vm_ops = &nilfs_file_vm_ops;
 150         vma->vm_flags |= VM_CAN_NONLINEAR;
 151         return 0;
 152 }
 153
 154 /*
 155  * We have mostly NULL's here: the current defaults are ok for
 156  * the nilfs filesystem.
 157  */
 158 struct file_operations nilfs_file_operations = {
 159         .llseek         = generic_file_llseek,
 160         .read           = do_sync_read,
 161         .write          = do_sync_write,
 162         .aio_read       = generic_file_aio_read,
 163         .aio_write      = nilfs_file_aio_write,
 164         .ioctl          = nilfs_ioctl,
 165 #ifdef CONFIG_COMPAT
 166         .compat_ioctl   = nilfs_compat_ioctl,
 167 #endif  /* CONFIG_COMPAT */
 168         .mmap           = nilfs_file_mmap,
 169         .open           = generic_file_open,
 170         /* .release     = nilfs_release_file, */
 171         .fsync          = nilfs_sync_file,
 172         .splice_read    = generic_file_splice_read,
 173 };
 174
 175 struct inode_operations nilfs_file_inode_operations = {
 176         .truncate       = nilfs_truncate,
 177         .setattr        = nilfs_setattr,
 178         .permission     = nilfs_permission,
 179 };
 180
 181 /* end of file */