fs/xfs/xfs_dfrag.c - maze/linux - Git at Google

 /*
  * 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_mount.h"
 #include "xfs_bmap_btree.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
 #include "xfs_inode_item.h"
 #include "xfs_bmap.h"
 #include "xfs_itable.h"
 #include "xfs_dfrag.h"
 #include "xfs_error.h"
 #include "xfs_vnodeops.h"
 #include "xfs_trace.h"


 static int xfs_swap_extents(
 	xfs_inode_t	*ip,	/* target inode */
 	xfs_inode_t	*tip,	/* tmp inode */
 	xfs_swapext_t	*sxp);

 /*
  * ioctl interface for swapext
  */
 int
 xfs_swapext(
 	xfs_swapext_t	*sxp)
 {
 	xfs_inode_t     *ip, *tip;
 	struct file	*file, *tmp_file;
 	int		error = 0;

 	/* Pull information for the target fd */
 	file = fget((int)sxp->sx_fdtarget);
 	if (!file) {
 		error = XFS_ERROR(EINVAL);
 		goto out;
 	}

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

 	tmp_file = fget((int)sxp->sx_fdtmp);
 	if (!tmp_file) {
 		error = XFS_ERROR(EINVAL);
 		goto out_put_file;
 	}

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

 	if (IS_SWAPFILE(file->f_path.dentry->d_inode) ||
 	    IS_SWAPFILE(tmp_file->f_path.dentry->d_inode)) {
 		error = XFS_ERROR(EINVAL);
 		goto out_put_tmp_file;
 	}

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

 	if (ip->i_mount != tip->i_mount) {
 		error = XFS_ERROR(EINVAL);
 		goto out_put_tmp_file;
 	}

 	if (ip->i_ino == tip->i_ino) {
 		error = XFS_ERROR(EINVAL);
 		goto out_put_tmp_file;
 	}

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

 	error = xfs_swap_extents(ip, tip, sxp);

  out_put_tmp_file:
 	fput(tmp_file);
  out_put_file:
 	fput(file);
  out:
 	return error;
 }

 /*
  * We need to check that the format of the data fork in the temporary inode is
  * valid for the target inode before doing the swap. This is not a problem with
  * attr1 because of the fixed fork offset, but attr2 has a dynamically sized
  * data fork depending on the space the attribute fork is taking so we can get
  * invalid formats on the target inode.
  *
  * E.g. target has space for 7 extents in extent format, temp inode only has
  * space for 6.  If we defragment down to 7 extents, then the tmp format is a
  * btree, but when swapped it needs to be in extent format. Hence we can't just
  * blindly swap data forks on attr2 filesystems.
  *
  * Note that we check the swap in both directions so that we don't end up with
  * a corrupt temporary inode, either.
  *
  * Note that fixing the way xfs_fsr sets up the attribute fork in the source
  * inode will prevent this situation from occurring, so all we do here is
  * reject and log the attempt. basically we are putting the responsibility on
  * userspace to get this right.
  */
 static int
 xfs_swap_extents_check_format(
 	xfs_inode_t	*ip,	/* target inode */
 	xfs_inode_t	*tip)	/* tmp inode */
 {

 	/* 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)
 		return EINVAL;

 	/*
 	 * if the target inode has less extents that then temporary inode then
 	 * why did userspace call us?
 	 */
 	if (ip->i_d.di_nextents < tip->i_d.di_nextents)
 		return EINVAL;

 	/*
 	 * if the target inode is in extent form and the temp inode is in btree
 	 * form then we will end up with the target inode in the wrong format
 	 * as we already know there are less extents in the temp inode.
 	 */
 	if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
 	    tip->i_d.di_format == XFS_DINODE_FMT_BTREE)
 		return EINVAL;

 	/* Check temp in extent form to max in target */
 	if (tip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
 	    XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) > ip->i_df.if_ext_max)
 		return EINVAL;

 	/* Check target in extent form to max in temp */
 	if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
 	    XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) > tip->i_df.if_ext_max)
 		return EINVAL;

 	/*
 	 * If we are in a btree format, check that the temp root block will fit
 	 * in the target and that it has enough extents to be in btree format
 	 * in the target.
 	 *
 	 * Note that we have to be careful to allow btree->extent conversions
 	 * (a common defrag case) which will occur when the temp inode is in
 	 * extent format...
 	 */
 	if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
 	    ((XFS_IFORK_BOFF(ip) &&
 	      tip->i_df.if_broot_bytes > XFS_IFORK_BOFF(ip)) ||
 	     XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <= ip->i_df.if_ext_max))
 		return EINVAL;

 	/* Reciprocal target->temp btree format checks */
 	if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
 	    ((XFS_IFORK_BOFF(tip) &&
 	      ip->i_df.if_broot_bytes > XFS_IFORK_BOFF(tip)) ||
 	     XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <= tip->i_df.if_ext_max))
 		return EINVAL;

 	return 0;
 }

 static int
 xfs_swap_extents(
 	xfs_inode_t	*ip,	/* target inode */
 	xfs_inode_t	*tip,	/* tmp inode */
 	xfs_swapext_t	*sxp)
 {
 	xfs_mount_t	*mp;
 	xfs_trans_t	*tp;
 	xfs_bstat_t	*sbp = &sxp->sx_stat;
 	xfs_ifork_t	*tempifp, *ifp, *tifp;
 	int		ilf_fields, tilf_fields;
 	int		error = 0;
 	int		aforkblks = 0;
 	int		taforkblks = 0;
 	__uint64_t	tmp;

 	mp = ip->i_mount;

 	tempifp = kmem_alloc(sizeof(xfs_ifork_t), KM_MAYFAIL);
 	if (!tempifp) {
 		error = XFS_ERROR(ENOMEM);
 		goto out;
 	}

 	sbp = &sxp->sx_stat;

 	/*
 	 * we have to do two separate lock calls here to keep lockdep
 	 * happy. If we try to get all the locks in one call, lock will
 	 * report false positives when we drop the ILOCK and regain them
 	 * below.
 	 */
 	xfs_lock_two_inodes(ip, tip, XFS_IOLOCK_EXCL);
 	xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);

 	/* 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 out_unlock;
 	}

 	/* 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 out_unlock;
 	}

 	if (VN_CACHED(VFS_I(tip)) != 0) {
 		error = xfs_flushinval_pages(tip, 0, -1,
 				FI_REMAPF_LOCKED);
 		if (error)
 			goto out_unlock;
 	}

 	/* Verify O_DIRECT for ftmp */
 	if (VN_CACHED(VFS_I(tip)) != 0) {
 		error = XFS_ERROR(EINVAL);
 		goto out_unlock;
 	}

 	/* 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 out_unlock;
 	}

 	trace_xfs_swap_extent_before(ip, 0);
 	trace_xfs_swap_extent_before(tip, 1);

 	/* check inode formats now that data is flushed */
 	error = xfs_swap_extents_check_format(ip, tip);
 	if (error) {
 		xfs_fs_cmn_err(CE_NOTE, mp,
 		    "%s: inode 0x%llx format is incompatible for exchanging.",
 				__FILE__, ip->i_ino);
 		goto out_unlock;
 	}

 	/*
 	 * 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 != VFS_I(ip)->i_ctime.tv_sec) ||
 	    (sbp->bs_ctime.tv_nsec != VFS_I(ip)->i_ctime.tv_nsec) ||
 	    (sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) ||
 	    (sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
 		error = XFS_ERROR(EBUSY);
 		goto out_unlock;
 	}

 	/* 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(VFS_I(ip))) {
 		error = XFS_ERROR(EBUSY);
 		goto out_unlock;
 	}

 	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);
 		goto out;
 	}
 	xfs_lock_two_inodes(ip, tip, 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)
 			goto out_trans_cancel;
 	}
 	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)
 			goto out_trans_cancel;
 	}

 	/*
 	 * 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 in-memory data fork values that are dependent on the fork
 	 * offset in the inode. We can't assume they remain the same as attr2
 	 * has dynamic fork offsets.
 	 */
 	ifp->if_ext_max = XFS_IFORK_SIZE(ip, XFS_DATA_FORK) /
 					(uint)sizeof(xfs_bmbt_rec_t);
 	tifp->if_ext_max = XFS_IFORK_SIZE(tip, XFS_DATA_FORK) /
 					(uint)sizeof(xfs_bmbt_rec_t);

 	/*
 	 * 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;

 	/*
 	 * The extents in the source inode could still contain speculative
 	 * preallocation beyond EOF (e.g. the file is open but not modified
 	 * while defrag is in progress). In that case, we need to copy over the
 	 * number of delalloc blocks the data fork in the source inode is
 	 * tracking beyond EOF so that when the fork is truncated away when the
 	 * temporary inode is unlinked we don't underrun the i_delayed_blks
 	 * counter on that inode.
 	 */
 	ASSERT(tip->i_delayed_blks == 0);
 	tip->i_delayed_blks = ip->i_delayed_blks;
 	ip->i_delayed_blks = 0;

 	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;
 	}


 	xfs_trans_ijoin_ref(tp, ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 	xfs_trans_ijoin_ref(tp, tip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);

 	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);

 	trace_xfs_swap_extent_after(ip, 0);
 	trace_xfs_swap_extent_after(tip, 1);
 out:
 	kmem_free(tempifp);
 	return error;

 out_unlock:
 	xfs_iunlock(ip,  XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 	xfs_iunlock(tip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
 	goto out;

 out_trans_cancel:
 	xfs_trans_cancel(tp, 0);
 	goto out_unlock;
 }
	/*
	* 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_mount.h"
	#include "xfs_bmap_btree.h"
	#include "xfs_dinode.h"
	#include "xfs_inode.h"
	#include "xfs_inode_item.h"
	#include "xfs_bmap.h"
	#include "xfs_itable.h"
	#include "xfs_dfrag.h"
	#include "xfs_error.h"
	#include "xfs_vnodeops.h"
	#include "xfs_trace.h"


	static int xfs_swap_extents(
	xfs_inode_t ip, / target inode */
	xfs_inode_t tip, / tmp inode */
	xfs_swapext_t *sxp);

	/*
	* ioctl interface for swapext
	*/
	int
	xfs_swapext(
	xfs_swapext_t *sxp)
	{
	xfs_inode_t ip, tip;
	struct file file, tmp_file;
	int error = 0;

	/* Pull information for the target fd */
	file = fget((int)sxp->sx_fdtarget);
	if (!file) {
	error = XFS_ERROR(EINVAL);
	goto out;
	}

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

	tmp_file = fget((int)sxp->sx_fdtmp);
	if (!tmp_file) {
	error = XFS_ERROR(EINVAL);
	goto out_put_file;
	}

	if (!(tmp_file->f_mode & FMODE_WRITE) \|\|
	!(tmp_file->f_mode & FMODE_READ) \|\|
	(tmp_file->f_flags & O_APPEND)) {
	error = XFS_ERROR(EBADF);
	goto out_put_tmp_file;
	}

	if (IS_SWAPFILE(file->f_path.dentry->d_inode) \|\|
	IS_SWAPFILE(tmp_file->f_path.dentry->d_inode)) {
	error = XFS_ERROR(EINVAL);
	goto out_put_tmp_file;
	}

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

	if (ip->i_mount != tip->i_mount) {
	error = XFS_ERROR(EINVAL);
	goto out_put_tmp_file;
	}

	if (ip->i_ino == tip->i_ino) {
	error = XFS_ERROR(EINVAL);
	goto out_put_tmp_file;
	}

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

	error = xfs_swap_extents(ip, tip, sxp);

	out_put_tmp_file:
	fput(tmp_file);
	out_put_file:
	fput(file);
	out:
	return error;
	}

	/*
	* We need to check that the format of the data fork in the temporary inode is
	* valid for the target inode before doing the swap. This is not a problem with
	* attr1 because of the fixed fork offset, but attr2 has a dynamically sized
	* data fork depending on the space the attribute fork is taking so we can get
	* invalid formats on the target inode.
	*
	* E.g. target has space for 7 extents in extent format, temp inode only has
	* space for 6. If we defragment down to 7 extents, then the tmp format is a
	* btree, but when swapped it needs to be in extent format. Hence we can't just
	* blindly swap data forks on attr2 filesystems.
	*
	* Note that we check the swap in both directions so that we don't end up with
	* a corrupt temporary inode, either.
	*
	* Note that fixing the way xfs_fsr sets up the attribute fork in the source
	* inode will prevent this situation from occurring, so all we do here is
	* reject and log the attempt. basically we are putting the responsibility on
	* userspace to get this right.
	*/
	static int
	xfs_swap_extents_check_format(
	xfs_inode_t ip, / target inode */
	xfs_inode_t tip) / tmp inode */
	{

	/* 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)
	return EINVAL;

	/*
	* if the target inode has less extents that then temporary inode then
	* why did userspace call us?
	*/
	if (ip->i_d.di_nextents < tip->i_d.di_nextents)
	return EINVAL;

	/*
	* if the target inode is in extent form and the temp inode is in btree
	* form then we will end up with the target inode in the wrong format
	* as we already know there are less extents in the temp inode.
	*/
	if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
	tip->i_d.di_format == XFS_DINODE_FMT_BTREE)
	return EINVAL;

	/* Check temp in extent form to max in target */
	if (tip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
	XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) > ip->i_df.if_ext_max)
	return EINVAL;

	/* Check target in extent form to max in temp */
	if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
	XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) > tip->i_df.if_ext_max)
	return EINVAL;

	/*
	* If we are in a btree format, check that the temp root block will fit
	* in the target and that it has enough extents to be in btree format
	* in the target.
	*
	* Note that we have to be careful to allow btree->extent conversions
	* (a common defrag case) which will occur when the temp inode is in
	* extent format...
	*/
	if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
	((XFS_IFORK_BOFF(ip) &&
	tip->i_df.if_broot_bytes > XFS_IFORK_BOFF(ip)) \|\|
	XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <= ip->i_df.if_ext_max))
	return EINVAL;

	/* Reciprocal target->temp btree format checks */
	if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
	((XFS_IFORK_BOFF(tip) &&
	ip->i_df.if_broot_bytes > XFS_IFORK_BOFF(tip)) \|\|
	XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <= tip->i_df.if_ext_max))
	return EINVAL;

	return 0;
	}

	static int
	xfs_swap_extents(
	xfs_inode_t ip, / target inode */
	xfs_inode_t tip, / tmp inode */
	xfs_swapext_t *sxp)
	{
	xfs_mount_t *mp;
	xfs_trans_t *tp;
	xfs_bstat_t *sbp = &sxp->sx_stat;
	xfs_ifork_t tempifp, ifp, *tifp;
	int ilf_fields, tilf_fields;
	int error = 0;
	int aforkblks = 0;
	int taforkblks = 0;
	__uint64_t tmp;

	mp = ip->i_mount;

	tempifp = kmem_alloc(sizeof(xfs_ifork_t), KM_MAYFAIL);
	if (!tempifp) {
	error = XFS_ERROR(ENOMEM);
	goto out;
	}

	sbp = &sxp->sx_stat;

	/*
	* we have to do two separate lock calls here to keep lockdep
	* happy. If we try to get all the locks in one call, lock will
	* report false positives when we drop the ILOCK and regain them
	* below.
	*/
	xfs_lock_two_inodes(ip, tip, XFS_IOLOCK_EXCL);
	xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);

	/* 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 out_unlock;
	}

	/* 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 out_unlock;
	}

	if (VN_CACHED(VFS_I(tip)) != 0) {
	error = xfs_flushinval_pages(tip, 0, -1,
	FI_REMAPF_LOCKED);
	if (error)
	goto out_unlock;
	}

	/* Verify O_DIRECT for ftmp */
	if (VN_CACHED(VFS_I(tip)) != 0) {
	error = XFS_ERROR(EINVAL);
	goto out_unlock;
	}

	/* 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 out_unlock;
	}

	trace_xfs_swap_extent_before(ip, 0);
	trace_xfs_swap_extent_before(tip, 1);

	/* check inode formats now that data is flushed */
	error = xfs_swap_extents_check_format(ip, tip);
	if (error) {
	xfs_fs_cmn_err(CE_NOTE, mp,
	"%s: inode 0x%llx format is incompatible for exchanging.",
	__FILE__, ip->i_ino);
	goto out_unlock;
	}

	/*
	* 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 != VFS_I(ip)->i_ctime.tv_sec) \|\|
	(sbp->bs_ctime.tv_nsec != VFS_I(ip)->i_ctime.tv_nsec) \|\|
	(sbp->bs_mtime.tv_sec != VFS_I(ip)->i_mtime.tv_sec) \|\|
	(sbp->bs_mtime.tv_nsec != VFS_I(ip)->i_mtime.tv_nsec)) {
	error = XFS_ERROR(EBUSY);
	goto out_unlock;
	}

	/* 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(VFS_I(ip))) {
	error = XFS_ERROR(EBUSY);
	goto out_unlock;
	}

	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);
	goto out;
	}
	xfs_lock_two_inodes(ip, tip, 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)
	goto out_trans_cancel;
	}
	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)
	goto out_trans_cancel;
	}

	/*
	* 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 in-memory data fork values that are dependent on the fork
	* offset in the inode. We can't assume they remain the same as attr2
	* has dynamic fork offsets.
	*/
	ifp->if_ext_max = XFS_IFORK_SIZE(ip, XFS_DATA_FORK) /
	(uint)sizeof(xfs_bmbt_rec_t);
	tifp->if_ext_max = XFS_IFORK_SIZE(tip, XFS_DATA_FORK) /
	(uint)sizeof(xfs_bmbt_rec_t);

	/*
	* 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;

	/*
	* The extents in the source inode could still contain speculative
	* preallocation beyond EOF (e.g. the file is open but not modified
	* while defrag is in progress). In that case, we need to copy over the
	* number of delalloc blocks the data fork in the source inode is
	* tracking beyond EOF so that when the fork is truncated away when the
	* temporary inode is unlinked we don't underrun the i_delayed_blks
	* counter on that inode.
	*/
	ASSERT(tip->i_delayed_blks == 0);
	tip->i_delayed_blks = ip->i_delayed_blks;
	ip->i_delayed_blks = 0;

	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;
	}


	xfs_trans_ijoin_ref(tp, ip, XFS_ILOCK_EXCL \| XFS_IOLOCK_EXCL);
	xfs_trans_ijoin_ref(tp, tip, XFS_ILOCK_EXCL \| XFS_IOLOCK_EXCL);

	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);

	trace_xfs_swap_extent_after(ip, 0);
	trace_xfs_swap_extent_after(tip, 1);
	out:
	kmem_free(tempifp);
	return error;

	out_unlock:
	xfs_iunlock(ip, XFS_ILOCK_EXCL \| XFS_IOLOCK_EXCL);
	xfs_iunlock(tip, XFS_ILOCK_EXCL \| XFS_IOLOCK_EXCL);
	goto out;

	out_trans_cancel:
	xfs_trans_cancel(tp, 0);
	goto out_unlock;
	}