text: /*
   * 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 <linux/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/uio.h>
  
  #include "udf_i.h"
  #include "udf_sb.h"
  
  static void __udf_adinicb_readpage(struct page *page)
  {
  	struct inode *inode = page->mapping->host;
  	char *kaddr;
  	struct udf_inode_info *iinfo = UDF_I(inode);
  	loff_t isize = i_size_read(inode);
  
  	/*
  	 * We have to be careful here as truncate can change i_size under us.
  	 * So just sample it once and use the same value everywhere.
  	 */
  	kaddr = kmap_atomic(page);
  	memcpy(kaddr, iinfo->i_ext.i_data + iinfo->i_lenEAttr, isize);
  	memset(kaddr + isize, 0, PAGE_SIZE - isize);
  	flush_dcache_page(page);
  	SetPageUptodate(page);
  	kunmap_atomic(kaddr);
  }
  
  static int udf_adinicb_readpage(struct file *file, struct page *page)
  {
  	BUG_ON(!PageLocked(page));
  	__udf_adinicb_readpage(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_atomic(page);
  	memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr,
  		i_size_read(inode));
  	SetPageUptodate(page);
  	kunmap_atomic(kaddr);
  	mark_inode_dirty(inode);
  	unlock_page(page);
  
  	return 0;
  }
  
  static int udf_adinicb_write_begin(struct file *file,
  			struct address_space *mapping, loff_t pos,
  			unsigned len, unsigned flags, struct page **pagep,
  			void **fsdata)
  {
  	struct page *page;
  
  	if (WARN_ON_ONCE(pos >= PAGE_SIZE))
  		return -EIO;
  	page = grab_cache_page_write_begin(mapping, 0, flags);
  	if (!page)
  		return -ENOMEM;
  	*pagep = page;
  
  	if (!PageUptodate(page))
  		__udf_adinicb_readpage(page);
  	return 0;
  }
  
  static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
  {
  	/* Fallback to buffered I/O. */
  	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 = page->mapping->host;
  	loff_t last_pos = pos + copied;
  	if (last_pos > inode->i_size)
  		i_size_write(inode, last_pos);
  	set_page_dirty(page);
  	unlock_page(page);
  	put_page(page);
  	return copied;
  }
  
  const struct address_space_operations udf_adinicb_aops = {
  	.readpage	= udf_adinicb_readpage,
  	.writepage	= udf_adinicb_writepage,
  	.write_begin	= udf_adinicb_write_begin,
  	.write_end	= udf_adinicb_write_end,
  	.direct_IO	= udf_adinicb_direct_IO,
  };
  
  static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
  {
  	ssize_t retval;
  	struct file *file = iocb->ki_filp;
  	struct inode *inode = file_inode(file);
  	struct udf_inode_info *iinfo = UDF_I(inode);
  	int err;
  
  	inode_lock(inode);
  
  	retval = generic_write_checks(iocb, from);
  	if (retval <= 0)
  		goto out;
  
  	down_write(&iinfo->i_data_sem);
  	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
  		loff_t end = iocb->ki_pos + iov_iter_count(from);
  
  		if (inode->i_sb->s_blocksize <
  				(udf_file_entry_alloc_offset(inode) + end)) {
  			err = udf_expand_file_adinicb(inode);
  			if (err) {
  				inode_unlock(inode);
  				udf_debug("udf_expand_adinicb: err=%d\n", err);
  				return err;
  			}
  		} else {
  			iinfo->i_lenAlloc = max(end, inode->i_size);
  			up_write(&iinfo->i_data_sem);
  		}
  	} else
  		up_write(&iinfo->i_data_sem);
  
  	retval = __generic_file_write_iter(iocb, from);
  out:
  	inode_unlock(inode);
  
  	if (retval > 0) {
  		mark_inode_dirty(inode);
  		retval = generic_write_sync(iocb, retval);
  	}
  
  	return retval;
  }
  
  long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  {
  	struct inode *inode = file_inode(filp);
  	long old_block, new_block;
  	int result;
  
  	if (inode_permission(inode, MAY_READ) != 0) {
  		udf_debug("no permission to access inode %lu\n", inode->i_ino);
  		return -EPERM;
  	}
  
  	if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) ||
  		     (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) {
  		udf_debug("invalid argument to udf_ioctl\n");
  		return -EINVAL;
  	}
  
  	switch (cmd) {
  	case UDF_GETVOLIDENT:
  		if (copy_to_user((char __user *)arg,
  				 UDF_SB(inode->i_sb)->s_volume_ident, 32))
  			return -EFAULT;
  		return 0;
  	case UDF_RELOCATE_BLOCKS:
  		if (!capable(CAP_SYS_ADMIN))
  			return -EPERM;
  		if (get_user(old_block, (long __user *)arg))
  			return -EFAULT;
  		result = udf_relocate_blocks(inode->i_sb,
  						old_block, &new_block);
  		if (result == 0)
  			result = put_user(new_block, (long __user *)arg);
  		return result;
  	case UDF_GETEASIZE:
  		return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
  	case UDF_GETEABLOCK:
  		return copy_to_user((char __user *)arg,
  				    UDF_I(inode)->i_ext.i_data,
  				    UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
  	default:
  		return -ENOIOCTLCMD;
  	}
  
  	return 0;
  }
  
  static int udf_release_file(struct inode *inode, struct file *filp)
  {
  	if (filp->f_mode & FMODE_WRITE &&
  	    atomic_read(&inode->i_writecount) == 1) {
  		/*
  		 * Grab i_mutex to avoid races with writes changing i_size
  		 * while we are running.
  		 */
  		inode_lock(inode);
  		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);
  		inode_unlock(inode);
  	}
  	return 0;
  }
  
  const struct file_operations udf_file_operations = {
  	.read_iter		= generic_file_read_iter,
  	.unlocked_ioctl		= udf_ioctl,
  	.open			= generic_file_open,
  	.mmap			= generic_file_mmap,
  	.write_iter		= udf_file_write_iter,
  	.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 = d_inode(dentry);
  	int error;
  
  	error = setattr_prepare(dentry, 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,
  };
  