/*

   * Copyright (c) 2000-2006 Silicon Graphics, Inc.

   * All Rights Reserved.

   *

   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as

   * published by the Free Software Foundation.
   *

   * This program is distributed in the hope that it would be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.

   *

   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write the Free Software Foundation,
   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

   */

  #include "xfs.h"

  #include "xfs_fs.h"

  #include "xfs_types.h"

  #include "xfs_bit.h"

  #include "xfs_log.h"

  #include "xfs_inum.h"

  #include "xfs_trans.h"
  #include "xfs_sb.h"

  #include "xfs_ag.h"

  #include "xfs_dir2.h"
  #include "xfs_dmapi.h"
  #include "xfs_mount.h"

  #include "xfs_bmap_btree.h"

  #include "xfs_alloc_btree.h"

  #include "xfs_ialloc_btree.h"

  #include "xfs_dir2_sf.h"

  #include "xfs_attr_sf.h"

  #include "xfs_dinode.h"

  #include "xfs_inode.h"

  #include "xfs_inode_item.h"

  #include "xfs_bmap.h"

  #include "xfs_btree.h"

  #include "xfs_ialloc.h"
  #include "xfs_itable.h"
  #include "xfs_dfrag.h"
  #include "xfs_error.h"

  #include "xfs_rw.h"

  #include "xfs_vnodeops.h"

  
  /*
   * Syssgi interface for swapext
   */
  int
  xfs_swapext(

  	xfs_swapext_t	__user *sxu)

  {

  	xfs_swapext_t	*sxp;

  	xfs_inode_t     *ip, *tip;
  	struct file	*file, *target_file;

  	int		error = 0;

  	sxp = kmem_alloc(sizeof(xfs_swapext_t), KM_MAYFAIL);

  	if (!sxp) {

  		error = XFS_ERROR(ENOMEM);

  		goto out;

  	}
  
  	if (copy_from_user(sxp, sxu, sizeof(xfs_swapext_t))) {
  		error = XFS_ERROR(EFAULT);

  		goto out_free_sxp;

  	}

  
  	/* Pull information for the target fd */

  	file = fget((int)sxp->sx_fdtarget);
  	if (!file) {

  		error = XFS_ERROR(EINVAL);

  		goto out_free_sxp;

  	}

  	if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND)) {
  		error = XFS_ERROR(EBADF);
  		goto out_put_file;
  	}

  	target_file = fget((int)sxp->sx_fdtmp);
  	if (!target_file) {

  		error = XFS_ERROR(EINVAL);

  		goto out_put_file;

  	}

  	if (!(target_file->f_mode & FMODE_WRITE) ||
  	    (target_file->f_flags & O_APPEND)) {
  		error = XFS_ERROR(EBADF);
  		goto out_put_target_file;
  	}

  	ip = XFS_I(file->f_path.dentry->d_inode);
  	tip = XFS_I(target_file->f_path.dentry->d_inode);

  
  	if (ip->i_mount != tip->i_mount) {

  		error = XFS_ERROR(EINVAL);
  		goto out_put_target_file;

  	}
  
  	if (ip->i_ino == tip->i_ino) {

  		error = XFS_ERROR(EINVAL);
  		goto out_put_target_file;

  	}

  	if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
  		error = XFS_ERROR(EIO);
  		goto out_put_target_file;

  	}

  	error = xfs_swap_extents(ip, tip, sxp);

   out_put_target_file:
  	fput(target_file);
   out_put_file:
  	fput(file);
   out_free_sxp:
  	kmem_free(sxp, sizeof(xfs_swapext_t));
   out:

  	return error;
  }
  
  int
  xfs_swap_extents(
  	xfs_inode_t	*ip,
  	xfs_inode_t	*tip,
  	xfs_swapext_t	*sxp)
  {
  	xfs_mount_t	*mp;
  	xfs_inode_t	*ips[2];
  	xfs_trans_t	*tp;
  	xfs_bstat_t	*sbp = &sxp->sx_stat;

  	bhv_vnode_t	*vp, *tvp;

  	xfs_ifork_t	*tempifp, *ifp, *tifp;
  	int		ilf_fields, tilf_fields;
  	static uint	lock_flags = XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL;
  	int		error = 0;
  	int		aforkblks = 0;
  	int		taforkblks = 0;
  	__uint64_t	tmp;
  	char		locked = 0;
  
  	mp = ip->i_mount;
  
  	tempifp = kmem_alloc(sizeof(xfs_ifork_t), KM_MAYFAIL);
  	if (!tempifp) {
  		error = XFS_ERROR(ENOMEM);
  		goto error0;
  	}
  
  	sbp = &sxp->sx_stat;
  	vp = XFS_ITOV(ip);
  	tvp = XFS_ITOV(tip);

  
  	/* Lock in i_ino order */
  	if (ip->i_ino < tip->i_ino) {
  		ips[0] = ip;
  		ips[1] = tip;
  	} else {
  		ips[0] = tip;
  		ips[1] = ip;
  	}

  	xfs_lock_inodes(ips, 2, lock_flags);

  	locked = 1;

  	/* Verify that both files have the same format */
  	if ((ip->i_d.di_mode & S_IFMT) != (tip->i_d.di_mode & S_IFMT)) {
  		error = XFS_ERROR(EINVAL);
  		goto error0;
  	}
  
  	/* Verify both files are either real-time or non-realtime */

  	if (XFS_IS_REALTIME_INODE(ip) != XFS_IS_REALTIME_INODE(tip)) {

  		error = XFS_ERROR(EINVAL);
  		goto error0;
  	}
  
  	/* Should never get a local format */
  	if (ip->i_d.di_format == XFS_DINODE_FMT_LOCAL ||
  	    tip->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
  		error = XFS_ERROR(EINVAL);
  		goto error0;
  	}

  	if (VN_CACHED(tvp) != 0) {

  		xfs_inval_cached_trace(tip, 0, -1, 0, -1);

  		error = xfs_flushinval_pages(tip, 0, -1,
  				FI_REMAPF_LOCKED);

  		if (error)
  			goto error0;

  	}

  
  	/* Verify O_DIRECT for ftmp */
  	if (VN_CACHED(tvp) != 0) {
  		error = XFS_ERROR(EINVAL);
  		goto error0;
  	}
  
  	/* Verify all data are being swapped */

  	if (sxp->sx_offset != 0 ||
  	    sxp->sx_length != ip->i_d.di_size ||
  	    sxp->sx_length != tip->i_d.di_size) {

  		error = XFS_ERROR(EFAULT);
  		goto error0;
  	}
  
  	/*
  	 * If the target has extended attributes, the tmp file
  	 * must also in order to ensure the correct data fork
  	 * format.
  	 */
  	if ( XFS_IFORK_Q(ip) != XFS_IFORK_Q(tip) ) {
  		error = XFS_ERROR(EINVAL);
  		goto error0;
  	}
  
  	/*
  	 * Compare the current change & modify times with that
  	 * passed in.  If they differ, we abort this swap.
  	 * This is the mechanism used to ensure the calling
  	 * process that the file was not changed out from
  	 * under it.
  	 */
  	if ((sbp->bs_ctime.tv_sec != ip->i_d.di_ctime.t_sec) ||
  	    (sbp->bs_ctime.tv_nsec != ip->i_d.di_ctime.t_nsec) ||
  	    (sbp->bs_mtime.tv_sec != ip->i_d.di_mtime.t_sec) ||
  	    (sbp->bs_mtime.tv_nsec != ip->i_d.di_mtime.t_nsec)) {
  		error = XFS_ERROR(EBUSY);
  		goto error0;
  	}
  
  	/* We need to fail if the file is memory mapped.  Once we have tossed
  	 * all existing pages, the page fault will have no option
  	 * but to go to the filesystem for pages. By making the page fault call

  	 * vop_read (or write in the case of autogrow) they block on the iolock

  	 * until we have switched the extents.
  	 */
  	if (VN_MAPPED(vp)) {
  		error = XFS_ERROR(EBUSY);
  		goto error0;
  	}
  
  	xfs_iunlock(ip, XFS_ILOCK_EXCL);
  	xfs_iunlock(tip, XFS_ILOCK_EXCL);
  
  	/*
  	 * There is a race condition here since we gave up the
  	 * ilock.  However, the data fork will not change since
  	 * we have the iolock (locked for truncation too) so we
  	 * are safe.  We don't really care if non-io related
  	 * fields change.
  	 */

  	xfs_tosspages(ip, 0, -1, FI_REMAPF);

  
  	tp = xfs_trans_alloc(mp, XFS_TRANS_SWAPEXT);
  	if ((error = xfs_trans_reserve(tp, 0,
  				     XFS_ICHANGE_LOG_RES(mp), 0,
  				     0, 0))) {
  		xfs_iunlock(ip,  XFS_IOLOCK_EXCL);
  		xfs_iunlock(tip, XFS_IOLOCK_EXCL);
  		xfs_trans_cancel(tp, 0);

  		locked = 0;
  		goto error0;

  	}

  	xfs_lock_inodes(ips, 2, XFS_ILOCK_EXCL);

  
  	/*
  	 * Count the number of extended attribute blocks
  	 */
  	if ( ((XFS_IFORK_Q(ip) != 0) && (ip->i_d.di_anextents > 0)) &&
  	     (ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
  		error = xfs_bmap_count_blocks(tp, ip, XFS_ATTR_FORK, &aforkblks);
  		if (error) {

  			xfs_trans_cancel(tp, 0);

  			goto error0;

  		}
  	}
  	if ( ((XFS_IFORK_Q(tip) != 0) && (tip->i_d.di_anextents > 0)) &&
  	     (tip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL)) {
  		error = xfs_bmap_count_blocks(tp, tip, XFS_ATTR_FORK,
  			&taforkblks);
  		if (error) {

  			xfs_trans_cancel(tp, 0);

  			goto error0;

  		}
  	}
  
  	/*
  	 * Swap the data forks of the inodes
  	 */
  	ifp = &ip->i_df;
  	tifp = &tip->i_df;

  	*tempifp = *ifp;	/* struct copy */
  	*ifp = *tifp;		/* struct copy */
  	*tifp = *tempifp;	/* struct copy */

  
  	/*
  	 * Fix the on-disk inode values
  	 */
  	tmp = (__uint64_t)ip->i_d.di_nblocks;
  	ip->i_d.di_nblocks = tip->i_d.di_nblocks - taforkblks + aforkblks;
  	tip->i_d.di_nblocks = tmp + taforkblks - aforkblks;
  
  	tmp = (__uint64_t) ip->i_d.di_nextents;
  	ip->i_d.di_nextents = tip->i_d.di_nextents;
  	tip->i_d.di_nextents = tmp;
  
  	tmp = (__uint64_t) ip->i_d.di_format;
  	ip->i_d.di_format = tip->i_d.di_format;
  	tip->i_d.di_format = tmp;
  
  	ilf_fields = XFS_ILOG_CORE;
  
  	switch(ip->i_d.di_format) {
  	case XFS_DINODE_FMT_EXTENTS:
  		/* If the extents fit in the inode, fix the
  		 * pointer.  Otherwise it's already NULL or
  		 * pointing to the extent.
  		 */
  		if (ip->i_d.di_nextents <= XFS_INLINE_EXTS) {
  			ifp->if_u1.if_extents =
  				ifp->if_u2.if_inline_ext;
  		}
  		ilf_fields |= XFS_ILOG_DEXT;
  		break;
  	case XFS_DINODE_FMT_BTREE:
  		ilf_fields |= XFS_ILOG_DBROOT;
  		break;
  	}
  
  	tilf_fields = XFS_ILOG_CORE;
  
  	switch(tip->i_d.di_format) {
  	case XFS_DINODE_FMT_EXTENTS:
  		/* If the extents fit in the inode, fix the
  		 * pointer.  Otherwise it's already NULL or
  		 * pointing to the extent.
  		 */
  		if (tip->i_d.di_nextents <= XFS_INLINE_EXTS) {
  			tifp->if_u1.if_extents =
  				tifp->if_u2.if_inline_ext;
  		}
  		tilf_fields |= XFS_ILOG_DEXT;
  		break;
  	case XFS_DINODE_FMT_BTREE:
  		tilf_fields |= XFS_ILOG_DBROOT;
  		break;
  	}
  
  	/*
  	 * Increment vnode ref counts since xfs_trans_commit &
  	 * xfs_trans_cancel will both unlock the inodes and
  	 * decrement the associated ref counts.
  	 */
  	VN_HOLD(vp);
  	VN_HOLD(tvp);
  
  	xfs_trans_ijoin(tp, ip, lock_flags);
  	xfs_trans_ijoin(tp, tip, lock_flags);
  
  	xfs_trans_log_inode(tp, ip,  ilf_fields);
  	xfs_trans_log_inode(tp, tip, tilf_fields);
  
  	/*
  	 * If this is a synchronous mount, make sure that the
  	 * transaction goes to disk before returning to the user.
  	 */
  	if (mp->m_flags & XFS_MOUNT_WSYNC) {
  		xfs_trans_set_sync(tp);
  	}

  	error = xfs_trans_commit(tp, XFS_TRANS_SWAPEXT);

  	locked = 0;

  
   error0:
  	if (locked) {
  		xfs_iunlock(ip,  lock_flags);
  		xfs_iunlock(tip, lock_flags);
  	}

  	if (tempifp != NULL)
  		kmem_free(tempifp, sizeof(xfs_ifork_t));

  	return error;
  }