/*
   * file.c
   *
   * PURPOSE
   *  File handling routines for the OSTA-UDF(tm) filesystem.
   *

   * COPYRIGHT
   *  This file is distributed under the terms of the GNU General Public
   *  License (GPL). Copies of the GPL can be obtained from:
   *    ftp://prep.ai.mit.edu/pub/gnu/GPL
   *  Each contributing author retains all rights to their own work.
   *
   *  (C) 1998-1999 Dave Boynton
   *  (C) 1998-2004 Ben Fennema
   *  (C) 1999-2000 Stelias Computing Inc
   *
   * HISTORY
   *
   *  10/02/98 dgb  Attempt to integrate into udf.o
   *  10/07/98      Switched to using generic_readpage, etc., like isofs
   *                And it works!
   *  12/06/98 blf  Added udf_file_read. uses generic_file_read for all cases but
   *                ICBTAG_FLAG_AD_IN_ICB.
   *  04/06/99      64 bit file handling on 32 bit systems taken from ext2 file.c
   *  05/12/99      Preliminary file write support
   */
  
  #include "udfdecl.h"
  #include <linux/fs.h>

  #include <asm/uaccess.h>
  #include <linux/kernel.h>

  #include <linux/string.h> /* memset */

  #include <linux/capability.h>

  #include <linux/errno.h>

  #include <linux/pagemap.h>
  #include <linux/buffer_head.h>

  #include <linux/aio.h>

  
  #include "udf_i.h"
  #include "udf_sb.h"

  static int udf_adinicb_readpage(struct file *file, struct page *page)

  {
  	struct inode *inode = page->mapping->host;
  	char *kaddr;

  	struct udf_inode_info *iinfo = UDF_I(inode);

  	BUG_ON(!PageLocked(page));

  
  	kaddr = kmap(page);
  	memset(kaddr, 0, PAGE_CACHE_SIZE);

  	memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, inode->i_size);

  	flush_dcache_page(page);
  	SetPageUptodate(page);
  	kunmap(page);
  	unlock_page(page);

  	return 0;
  }

  static int udf_adinicb_writepage(struct page *page,
  				 struct writeback_control *wbc)

  {
  	struct inode *inode = page->mapping->host;
  	char *kaddr;

  	struct udf_inode_info *iinfo = UDF_I(inode);

  	BUG_ON(!PageLocked(page));

  
  	kaddr = kmap(page);

  	memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr, inode->i_size);

  	mark_inode_dirty(inode);
  	SetPageUptodate(page);
  	kunmap(page);
  	unlock_page(page);

  	return 0;
  }

  static int udf_adinicb_write_end(struct file *file,
  			struct address_space *mapping,
  			loff_t pos, unsigned len, unsigned copied,
  			struct page *page, void *fsdata)

  {

  	struct inode *inode = mapping->host;
  	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
  	char *kaddr;

  	struct udf_inode_info *iinfo = UDF_I(inode);

  	kaddr = kmap_atomic(page, KM_USER0);

  	memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr + offset,

  		kaddr + offset, copied);
  	kunmap_atomic(kaddr, KM_USER0);
  
  	return simple_write_end(file, mapping, pos, len, copied, page, fsdata);

  }

  const struct address_space_operations udf_adinicb_aops = {

  	.readpage	= udf_adinicb_readpage,
  	.writepage	= udf_adinicb_writepage,

  	.write_begin = simple_write_begin,
  	.write_end = udf_adinicb_write_end,

  };

  static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,

  				  unsigned long nr_segs, loff_t ppos)

  {
  	ssize_t retval;

  	struct file *file = iocb->ki_filp;

  	struct inode *inode = file->f_path.dentry->d_inode;

  	int err, pos;

  	size_t count = iocb->ki_left;

  	struct udf_inode_info *iinfo = UDF_I(inode);

  	down_write(&iinfo->i_data_sem);

  	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {

  		if (file->f_flags & O_APPEND)
  			pos = inode->i_size;
  		else

  			pos = ppos;

  		if (inode->i_sb->s_blocksize <
  				(udf_file_entry_alloc_offset(inode) +

  						pos + count)) {

  			err = udf_expand_file_adinicb(inode);
  			if (err) {

  				udf_debug("udf_expand_adinicb: err=%d
  ", err);
  				return err;
  			}

  		} else {

  			if (pos + count > inode->i_size)

  				iinfo->i_lenAlloc = pos + count;

  			else

  				iinfo->i_lenAlloc = inode->i_size;

  			up_write(&iinfo->i_data_sem);

  		}

  	} else
  		up_write(&iinfo->i_data_sem);

  	retval = generic_file_aio_write(iocb, iov, nr_segs, ppos);

  	if (retval > 0)
  		mark_inode_dirty(inode);

  	return retval;
  }

  long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)

  {

  	struct inode *inode = filp->f_dentry->d_inode;

  	long old_block, new_block;

  	int result = -EINVAL;

  	if (inode_permission(inode, MAY_READ) != 0) {

  		udf_debug("no permission to access inode %lu
  ", inode->i_ino);
  		result = -EPERM;
  		goto out;

  	}

  	if (!arg) {

  		udf_debug("invalid argument to udf_ioctl
  ");

  		result = -EINVAL;
  		goto out;

  	}

  	switch (cmd) {
  	case UDF_GETVOLIDENT:

  		if (copy_to_user((char __user *)arg,
  				 UDF_SB(inode->i_sb)->s_volume_ident, 32))

  			result = -EFAULT;

  		else

  			result = 0;
  		goto out;

  	case UDF_RELOCATE_BLOCKS:

  		if (!capable(CAP_SYS_ADMIN)) {
  			result = -EACCES;
  			goto out;
  		}
  		if (get_user(old_block, (long __user *)arg)) {
  			result = -EFAULT;
  			goto out;
  		}

  		result = udf_relocate_blocks(inode->i_sb,
  						old_block, &new_block);
  		if (result == 0)

  			result = put_user(new_block, (long __user *)arg);

  		goto out;

  	case UDF_GETEASIZE:

  		result = put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);

  		goto out;

  	case UDF_GETEABLOCK:

  		result = copy_to_user((char __user *)arg,
  				      UDF_I(inode)->i_ext.i_data,
  				      UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;

  		goto out;

  	}

  out:

  	return result;
  }

  static int udf_release_file(struct inode *inode, struct file *filp)

  {

  	if (filp->f_mode & FMODE_WRITE) {

  		mutex_lock(&inode->i_mutex);

  		down_write(&UDF_I(inode)->i_data_sem);

  		udf_discard_prealloc(inode);

  		udf_truncate_tail_extent(inode);

  		up_write(&UDF_I(inode)->i_data_sem);

  		mutex_unlock(&inode->i_mutex);

  	}
  	return 0;
  }

  const struct file_operations udf_file_operations = {

  	.read			= do_sync_read,
  	.aio_read		= generic_file_aio_read,

  	.unlocked_ioctl		= udf_ioctl,

  	.open			= generic_file_open,

  	.mmap			= generic_file_mmap,
  	.write			= do_sync_write,
  	.aio_write		= udf_file_aio_write,
  	.release		= udf_release_file,

  	.fsync			= generic_file_fsync,

  	.splice_read		= generic_file_splice_read,

  	.llseek			= generic_file_llseek,

  };

  static int udf_setattr(struct dentry *dentry, struct iattr *attr)
  {
  	struct inode *inode = dentry->d_inode;
  	int error;
  
  	error = inode_change_ok(inode, attr);
  	if (error)
  		return error;

  
  	if ((attr->ia_valid & ATTR_SIZE) &&
  	    attr->ia_size != i_size_read(inode)) {

  		error = udf_setsize(inode, attr->ia_size);

  		if (error)
  			return error;
  	}
  
  	setattr_copy(inode, attr);
  	mark_inode_dirty(inode);
  	return 0;

  }

  const struct inode_operations udf_file_inode_operations = {

  	.setattr		= udf_setattr,

  };