/*

   * Copyright (c) 2000-2003,2005 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_log.h"

  #include "xfs_inum.h"

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

  #include "xfs_ag.h"

  #include "xfs_dir2.h"

  #include "xfs_mount.h"

  #include "xfs_da_btree.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_error.h"
  #include "xfs_quota.h"

  #include "xfs_utils.h"
  #include "xfs_trans_space.h"

  #include "xfs_vnodeops.h"

  #include "xfs_trace.h"

  
  
  /*

   * Enter all inodes for a rename transaction into a sorted array.

   */

  STATIC void
  xfs_sort_for_rename(

  	xfs_inode_t	*dp1,	/* in: old (source) directory inode */
  	xfs_inode_t	*dp2,	/* in: new (target) directory inode */
  	xfs_inode_t	*ip1,	/* in: inode of old entry */

  	xfs_inode_t	*ip2,	/* in: inode of new entry, if it

  				   already exists, NULL otherwise. */

  	xfs_inode_t	**i_tab,/* out: array of inode returned, sorted */
  	int		*num_inodes)  /* out: number of inodes in array */

  {

  	xfs_inode_t		*temp;

  	int			i, j;

  
  	/*
  	 * i_tab contains a list of pointers to inodes.  We initialize
  	 * the table here & we'll sort it.  We will then use it to
  	 * order the acquisition of the inode locks.
  	 *
  	 * Note that the table may contain duplicates.  e.g., dp1 == dp2.
  	 */
  	i_tab[0] = dp1;
  	i_tab[1] = dp2;
  	i_tab[2] = ip1;

  	if (ip2) {

  		*num_inodes = 4;
  		i_tab[3] = ip2;

  	} else {
  		*num_inodes = 3;
  		i_tab[3] = NULL;

  	}
  
  	/*
  	 * Sort the elements via bubble sort.  (Remember, there are at
  	 * most 4 elements to sort, so this is adequate.)
  	 */

  	for (i = 0; i < *num_inodes; i++) {
  		for (j = 1; j < *num_inodes; j++) {

  			if (i_tab[j]->i_ino < i_tab[j-1]->i_ino) {
  				temp = i_tab[j];
  				i_tab[j] = i_tab[j-1];
  				i_tab[j-1] = temp;
  			}
  		}
  	}

  }

  /*
   * xfs_rename
   */
  int
  xfs_rename(

  	xfs_inode_t	*src_dp,

  	struct xfs_name	*src_name,
  	xfs_inode_t	*src_ip,

  	xfs_inode_t	*target_dp,

  	struct xfs_name	*target_name,
  	xfs_inode_t	*target_ip)

  {

  	xfs_trans_t	*tp = NULL;

  	xfs_mount_t	*mp = src_dp->i_mount;

  	int		new_parent;		/* moving to a new dir */
  	int		src_is_directory;	/* src_name is a directory */
  	int		error;
  	xfs_bmap_free_t free_list;
  	xfs_fsblock_t   first_block;
  	int		cancel_flags;
  	int		committed;
  	xfs_inode_t	*inodes[4];

  	int		spaceres;

  	int		num_inodes;

  	trace_xfs_rename(src_dp, target_dp, src_name, target_name);

  	new_parent = (src_dp != target_dp);

  	src_is_directory = S_ISDIR(src_ip->i_d.di_mode);

  	if (src_is_directory) {

  		/*
  		 * Check for link count overflow on target_dp
  		 */

  		if (target_ip == NULL && new_parent &&

  		    target_dp->i_d.di_nlink >= XFS_MAXLINK) {

  			error = XFS_ERROR(EMLINK);

  			goto std_return;

  		}
  	}

  	xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip,
  				inodes, &num_inodes);

  	xfs_bmap_init(&free_list, &first_block);

  	tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
  	cancel_flags = XFS_TRANS_RELEASE_LOG_RES;

  	spaceres = XFS_RENAME_SPACE_RES(mp, target_name->len);

  	error = xfs_trans_reserve(tp, spaceres, XFS_RENAME_LOG_RES(mp), 0,
  			XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
  	if (error == ENOSPC) {
  		spaceres = 0;
  		error = xfs_trans_reserve(tp, 0, XFS_RENAME_LOG_RES(mp), 0,
  				XFS_TRANS_PERM_LOG_RES, XFS_RENAME_LOG_COUNT);
  	}
  	if (error) {

  		xfs_trans_cancel(tp, 0);

  		goto std_return;

  	}
  
  	/*
  	 * Attach the dquots to the inodes
  	 */

  	error = xfs_qm_vop_rename_dqattach(inodes);
  	if (error) {

  		xfs_trans_cancel(tp, cancel_flags);

  		goto std_return;

  	}
  
  	/*

  	 * Lock all the participating inodes. Depending upon whether
  	 * the target_name exists in the target directory, and
  	 * whether the target directory is the same as the source
  	 * directory, we can lock from 2 to 4 inodes.
  	 */
  	xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);
  
  	/*

  	 * Join all the inodes to the transaction. From this point on,
  	 * we can rely on either trans_commit or trans_cancel to unlock

  	 * them.

  	 */

  	xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);

  	if (new_parent)

  		xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
  	xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);

  	if (target_ip)

  		xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);

  
  	/*

  	 * If we are using project inheritance, we only allow renames
  	 * into our tree when the project IDs are the same; else the
  	 * tree quota mechanism would be circumvented.
  	 */
  	if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&

  		     (xfs_get_projid(target_dp) != xfs_get_projid(src_ip)))) {

  		error = XFS_ERROR(EXDEV);
  		goto error_return;
  	}
  
  	/*

  	 * Set up the target.
  	 */
  	if (target_ip == NULL) {
  		/*
  		 * If there's no space reservation, check the entry will
  		 * fit before actually inserting it.
  		 */

  		error = xfs_dir_canenter(tp, target_dp, target_name, spaceres);
  		if (error)

  			goto error_return;

  		/*
  		 * If target does not exist and the rename crosses
  		 * directories, adjust the target directory link count
  		 * to account for the ".." reference from the new entry.
  		 */

  		error = xfs_dir_createname(tp, target_dp, target_name,

  						src_ip->i_ino, &first_block,
  						&free_list, spaceres);

  		if (error == ENOSPC)

  			goto error_return;

  		if (error)

  			goto abort_return;

  
  		xfs_trans_ichgtime(tp, target_dp,
  					XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);

  
  		if (new_parent && src_is_directory) {
  			error = xfs_bumplink(tp, target_dp);

  			if (error)

  				goto abort_return;

  		}
  	} else { /* target_ip != NULL */

  		/*
  		 * If target exists and it's a directory, check that both
  		 * target and source are directories and that target can be
  		 * destroyed, or that neither is a directory.
  		 */

  		if (S_ISDIR(target_ip->i_d.di_mode)) {

  			/*
  			 * Make sure target dir is empty.
  			 */

  			if (!(xfs_dir_isempty(target_ip)) ||

  			    (target_ip->i_d.di_nlink > 2)) {
  				error = XFS_ERROR(EEXIST);

  				goto error_return;
  			}
  		}
  
  		/*
  		 * Link the source inode under the target name.
  		 * If the source inode is a directory and we are moving
  		 * it across directories, its ".." entry will be
  		 * inconsistent until we replace that down below.
  		 *
  		 * In case there is already an entry with the same
  		 * name at the destination directory, remove it first.
  		 */

  		error = xfs_dir_replace(tp, target_dp, target_name,

  					src_ip->i_ino,

  					&first_block, &free_list, spaceres);
  		if (error)

  			goto abort_return;

  
  		xfs_trans_ichgtime(tp, target_dp,
  					XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);

  
  		/*
  		 * Decrement the link count on the target since the target
  		 * dir no longer points to it.
  		 */
  		error = xfs_droplink(tp, target_ip);

  		if (error)

  			goto abort_return;

  
  		if (src_is_directory) {
  			/*
  			 * Drop the link from the old "." entry.
  			 */
  			error = xfs_droplink(tp, target_ip);

  			if (error)

  				goto abort_return;

  		}

  	} /* target_ip != NULL */
  
  	/*
  	 * Remove the source.
  	 */
  	if (new_parent && src_is_directory) {

  		/*
  		 * Rewrite the ".." entry to point to the new
  		 * directory.
  		 */

  		error = xfs_dir_replace(tp, src_ip, &xfs_name_dotdot,
  					target_dp->i_ino,

  					&first_block, &free_list, spaceres);

  		ASSERT(error != EEXIST);

  		if (error)

  			goto abort_return;

  	}
  
  	/*

  	 * We always want to hit the ctime on the source inode.
  	 *
  	 * This isn't strictly required by the standards since the source
  	 * inode isn't really being changed, but old unix file systems did
  	 * it and some incremental backup programs won't work without it.
  	 */

  	xfs_trans_ichgtime(tp, src_ip, XFS_ICHGTIME_CHG);

  	xfs_trans_log_inode(tp, src_ip, XFS_ILOG_CORE);

  
  	/*

  	 * Adjust the link count on src_dp.  This is necessary when
  	 * renaming a directory, either within one parent when
  	 * the target existed, or across two parent directories.
  	 */
  	if (src_is_directory && (new_parent || target_ip != NULL)) {
  
  		/*
  		 * Decrement link count on src_directory since the
  		 * entry that's moved no longer points to it.
  		 */
  		error = xfs_droplink(tp, src_dp);

  		if (error)

  			goto abort_return;

  	}

  	error = xfs_dir_removename(tp, src_dp, src_name, src_ip->i_ino,
  					&first_block, &free_list, spaceres);

  	if (error)

  		goto abort_return;

  	xfs_trans_ichgtime(tp, src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);

  	xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);

  	if (new_parent)

  		xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);

  
  	/*

  	 * If this is a synchronous mount, make sure that the
  	 * rename transaction goes to disk before returning to
  	 * the user.
  	 */
  	if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
  		xfs_trans_set_sync(tp);
  	}

  	error = xfs_bmap_finish(&tp, &free_list, &committed);

  	if (error) {
  		xfs_bmap_cancel(&free_list);
  		xfs_trans_cancel(tp, (XFS_TRANS_RELEASE_LOG_RES |
  				 XFS_TRANS_ABORT));

  		goto std_return;
  	}
  
  	/*
  	 * trans_commit will unlock src_ip, target_ip & decrement
  	 * the vnode references.
  	 */

  	return xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);

  
   abort_return:
  	cancel_flags |= XFS_TRANS_ABORT;

   error_return:
  	xfs_bmap_cancel(&free_list);
  	xfs_trans_cancel(tp, cancel_flags);

   std_return:
  	return error;

  }