text: /*
   * 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_dmapi.h"
  #include "xfs_mount.h"
  #include "xfs_da_btree.h"
  #include "xfs_bmap_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_error.h"
  #include "xfs_quota.h"
  #include "xfs_refcache.h"
  #include "xfs_utils.h"
  #include "xfs_trans_space.h"
  
  
  /*
   * Given an array of up to 4 inode pointers, unlock the pointed to inodes.
   * If there are fewer than 4 entries in the array, the empty entries will
   * be at the end and will have NULL pointers in them.
   */
  STATIC void
  xfs_rename_unlock4(
  	xfs_inode_t	**i_tab,
  	uint		lock_mode)
  {
  	int	i;
  
  	xfs_iunlock(i_tab[0], lock_mode);
  	for (i = 1; i < 4; i++) {
  		if (i_tab[i] == NULL) {
  			break;
  		}
  		/*
  		 * Watch out for duplicate entries in the table.
  		 */
  		if (i_tab[i] != i_tab[i-1]) {
  			xfs_iunlock(i_tab[i], lock_mode);
  		}
  	}
  }
  
  #ifdef DEBUG
  int xfs_rename_skip, xfs_rename_nskip;
  #endif
  
  /*
   * The following routine will acquire the locks required for a rename
   * operation. The code understands the semantics of renames and will
   * validate that name1 exists under dp1 & that name2 may or may not
   * exist under dp2.
   *
   * We are renaming dp1/name1 to dp2/name2.
   *
   * Return ENOENT if dp1 does not exist, other lookup errors, or 0 for success.
   */
  STATIC int
  xfs_lock_for_rename(
  	xfs_inode_t	*dp1,	/* old (source) directory inode */
  	xfs_inode_t	*dp2,	/* new (target) directory inode */
  	bhv_vname_t	*vname1,/* old entry name */
  	bhv_vname_t	*vname2,/* new entry name */
  	xfs_inode_t	**ipp1,	/* inode of old entry */
  	xfs_inode_t	**ipp2,	/* inode of new entry, if it
  				   already exists, NULL otherwise. */
  	xfs_inode_t	**i_tab,/* array of inode returned, sorted */
  	int		*num_inodes)  /* number of inodes in array */
  {
  	xfs_inode_t		*ip1, *ip2, *temp;
  	xfs_ino_t		inum1, inum2;
  	int			error;
  	int			i, j;
  	uint			lock_mode;
  	int			diff_dirs = (dp1 != dp2);
  
  	ip2 = NULL;
  
  	/*
  	 * First, find out the current inums of the entries so that we
  	 * can determine the initial locking order.  We'll have to
  	 * sanity check stuff after all the locks have been acquired
  	 * to see if we still have the right inodes, directories, etc.
  	 */
  	lock_mode = xfs_ilock_map_shared(dp1);
  	error = xfs_get_dir_entry(vname1, &ip1);
  	if (error) {
  		xfs_iunlock_map_shared(dp1, lock_mode);
  		return error;
  	}
  
  	inum1 = ip1->i_ino;
  
  	ASSERT(ip1);
  	ITRACE(ip1);
  
  	/*
  	 * Unlock dp1 and lock dp2 if they are different.
  	 */
  
  	if (diff_dirs) {
  		xfs_iunlock_map_shared(dp1, lock_mode);
  		lock_mode = xfs_ilock_map_shared(dp2);
  	}
  
  	error = xfs_dir_lookup_int(dp2, lock_mode, vname2, &inum2, &ip2);
  	if (error == ENOENT) {		/* target does not need to exist. */
  		inum2 = 0;
  	} else if (error) {
  		/*
  		 * If dp2 and dp1 are the same, the next line unlocks dp1.
  		 * Got it?
  		 */
  		xfs_iunlock_map_shared(dp2, lock_mode);
  		IRELE (ip1);
  		return error;
  	} else {
  		ITRACE(ip2);
  	}
  
  	/*
  	 * 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 (inum2 == 0) {
  		*num_inodes = 3;
  		i_tab[3] = NULL;
  	} else {
  		*num_inodes = 4;
  		i_tab[3] = ip2;
  	}
  
  	/*
  	 * 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;
  			}
  		}
  	}
  
  	/*
  	 * We have dp2 locked. If it isn't first, unlock it.
  	 * If it is first, tell xfs_lock_inodes so it can skip it
  	 * when locking. if dp1 == dp2, xfs_lock_inodes will skip both
  	 * since they are equal. xfs_lock_inodes needs all these inodes
  	 * so that it can unlock and retry if there might be a dead-lock
  	 * potential with the log.
  	 */
  
  	if (i_tab[0] == dp2 && lock_mode == XFS_ILOCK_SHARED) {
  #ifdef DEBUG
  		xfs_rename_skip++;
  #endif
  		xfs_lock_inodes(i_tab, *num_inodes, 1, XFS_ILOCK_SHARED);
  	} else {
  #ifdef DEBUG
  		xfs_rename_nskip++;
  #endif
  		xfs_iunlock_map_shared(dp2, lock_mode);
  		xfs_lock_inodes(i_tab, *num_inodes, 0, XFS_ILOCK_SHARED);
  	}
  
  	/*
  	 * Set the return value. Null out any unused entries in i_tab.
  	 */
  	*ipp1 = *ipp2 = NULL;
  	for (i=0; i < *num_inodes; i++) {
  		if (i_tab[i]->i_ino == inum1) {
  			*ipp1 = i_tab[i];
  		}
  		if (i_tab[i]->i_ino == inum2) {
  			*ipp2 = i_tab[i];
  		}
  	}
  	for (;i < 4; i++) {
  		i_tab[i] = NULL;
  	}
  	return 0;
  }
  
  /*
   * xfs_rename
   */
  int
  xfs_rename(
  	xfs_inode_t	*src_dp,
  	bhv_vname_t	*src_vname,
  	bhv_vnode_t	*target_dir_vp,
  	bhv_vname_t	*target_vname)
  {
  	bhv_vnode_t	*src_dir_vp = XFS_ITOV(src_dp);
  	xfs_trans_t	*tp;
  	xfs_inode_t	*target_dp, *src_ip, *target_ip;
  	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		target_ip_dropped = 0;	/* dropped target_ip link? */
  	int		spaceres;
  	int		target_link_zero = 0;
  	int		num_inodes;
  	char		*src_name = VNAME(src_vname);
  	char		*target_name = VNAME(target_vname);
  	int		src_namelen = VNAMELEN(src_vname);
  	int		target_namelen = VNAMELEN(target_vname);
  
  	vn_trace_entry(src_dp, "xfs_rename", (inst_t *)__return_address);
  	vn_trace_entry(xfs_vtoi(target_dir_vp), "xfs_rename", (inst_t *)__return_address);
  
  	/*
  	 * Find the XFS behavior descriptor for the target directory
  	 * vnode since it was not handed to us.
  	 */
  	target_dp = xfs_vtoi(target_dir_vp);
  	if (target_dp == NULL) {
  		return XFS_ERROR(EXDEV);
  	}
  
  	if (DM_EVENT_ENABLED(src_dp, DM_EVENT_RENAME) ||
  	    DM_EVENT_ENABLED(target_dp, DM_EVENT_RENAME)) {
  		error = XFS_SEND_NAMESP(mp, DM_EVENT_RENAME,
  					src_dir_vp, DM_RIGHT_NULL,
  					target_dir_vp, DM_RIGHT_NULL,
  					src_name, target_name,
  					0, 0, 0);
  		if (error) {
  			return error;
  		}
  	}
  	/* Return through std_return after this point. */
  
  	/*
  	 * 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_for_rename() will return ENOENT if src_name
  	 * does not exist in the source directory.
  	 */
  	tp = NULL;
  	error = xfs_lock_for_rename(src_dp, target_dp, src_vname,
  			target_vname, &src_ip, &target_ip, inodes,
  			&num_inodes);
  
  	if (error) {
  		/*
  		 * We have nothing locked, no inode references, and
  		 * no transaction, so just get out.
  		 */
  		goto std_return;
  	}
  
  	ASSERT(src_ip != NULL);
  
  	if ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
  		/*
  		 * Check for link count overflow on target_dp
  		 */
  		if (target_ip == NULL && (src_dp != target_dp) &&
  		    target_dp->i_d.di_nlink >= XFS_MAXLINK) {
  			error = XFS_ERROR(EMLINK);
  			xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
  			goto rele_return;
  		}
  	}
  
  	/*
  	 * 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) &&
  		     (target_dp->i_d.di_projid != src_ip->i_d.di_projid))) {
  		error = XFS_ERROR(EXDEV);
  		xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
  		goto rele_return;
  	}
  
  	new_parent = (src_dp != target_dp);
  	src_is_directory = ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR);
  
  	/*
  	 * Drop the locks on our inodes so that we can start the transaction.
  	 */
  	xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
  
  	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_namelen);
  	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 rele_return;
  	}
  
  	/*
  	 * Attach the dquots to the inodes
  	 */
  	if ((error = XFS_QM_DQVOPRENAME(mp, inodes))) {
  		xfs_trans_cancel(tp, cancel_flags);
  		goto rele_return;
  	}
  
  	/*
  	 * Reacquire the inode locks we dropped above.
  	 */
  	xfs_lock_inodes(inodes, num_inodes, 0, 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.  Note that we need to add a vnode reference to the
  	 * directories since trans_commit & trans_cancel will decrement
  	 * them when they unlock the inodes.  Also, we need to be careful
  	 * not to add an inode to the transaction more than once.
  	 */
  	VN_HOLD(src_dir_vp);
  	xfs_trans_ijoin(tp, src_dp, XFS_ILOCK_EXCL);
  	if (new_parent) {
  		VN_HOLD(target_dir_vp);
  		xfs_trans_ijoin(tp, target_dp, XFS_ILOCK_EXCL);
  	}
  	if ((src_ip != src_dp) && (src_ip != target_dp)) {
  		xfs_trans_ijoin(tp, src_ip, XFS_ILOCK_EXCL);
  	}
  	if ((target_ip != NULL) &&
  	    (target_ip != src_ip) &&
  	    (target_ip != src_dp) &&
  	    (target_ip != target_dp)) {
  		xfs_trans_ijoin(tp, target_ip, XFS_ILOCK_EXCL);
  	}
  
  	/*
  	 * Set up the target.
  	 */
  	if (target_ip == NULL) {
  		/*
  		 * If there's no space reservation, check the entry will
  		 * fit before actually inserting it.
  		 */
  		if (spaceres == 0 &&
  		    (error = xfs_dir_canenter(tp, target_dp, target_name,
  						target_namelen)))
  			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,
  					   target_namelen, src_ip->i_ino,
  					   &first_block, &free_list, spaceres);
  		if (error == ENOSPC)
  			goto error_return;
  		if (error)
  			goto abort_return;
  		xfs_ichgtime(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 ((target_ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
  			/*
  			 * 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,
  					target_namelen, src_ip->i_ino,
  					&first_block, &free_list, spaceres);
  		if (error)
  			goto abort_return;
  		xfs_ichgtime(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;
  		target_ip_dropped = 1;
  
  		if (src_is_directory) {
  			/*
  			 * Drop the link from the old "." entry.
  			 */
  			error = xfs_droplink(tp, target_ip);
  			if (error)
  				goto abort_return;
  		}
  
  		/* Do this test while we still hold the locks */
  		target_link_zero = (target_ip)->i_d.di_nlink==0;
  
  	} /* 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, "..", 2, target_dp->i_ino,
  					&first_block, &free_list, spaceres);
  		ASSERT(error != EEXIST);
  		if (error)
  			goto abort_return;
  		xfs_ichgtime(src_ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
  
  	} else {
  		/*
  		 * We always want to hit the ctime on the source inode.
  		 * We do it in the if clause above for the 'new_parent &&
  		 * src_is_directory' case, and here we get all the other
  		 * cases.  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_ichgtime(src_ip, XFS_ICHGTIME_CHG);
  	}
  
  	/*
  	 * 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_namelen,
  			src_ip->i_ino, &first_block, &free_list, spaceres);
  	if (error)
  		goto abort_return;
  	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
  
  	/*
  	 * Update the generation counts on all the directory inodes
  	 * that we're modifying.
  	 */
  	src_dp->i_gen++;
  	xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
  
  	if (new_parent) {
  		target_dp->i_gen++;
  		xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
  	}
  
  	/*
  	 * If there was a target inode, take an extra reference on
  	 * it here so that it doesn't go to xfs_inactive() from
  	 * within the commit.
  	 */
  	if (target_ip != NULL) {
  		IHOLD(target_ip);
  	}
  
  	/*
  	 * 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);
  	}
  
  	/*
  	 * Take refs. for vop_link_removed calls below.  No need to worry
  	 * about directory refs. because the caller holds them.
  	 *
  	 * Do holds before the xfs_bmap_finish since it might rele them down
  	 * to zero.
  	 */
  
  	if (target_ip_dropped)
  		IHOLD(target_ip);
  	IHOLD(src_ip);
  
  	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));
  		if (target_ip != NULL) {
  			IRELE(target_ip);
  		}
  		if (target_ip_dropped) {
  			IRELE(target_ip);
  		}
  		IRELE(src_ip);
  		goto std_return;
  	}
  
  	/*
  	 * trans_commit will unlock src_ip, target_ip & decrement
  	 * the vnode references.
  	 */
  	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
  	if (target_ip != NULL) {
  		xfs_refcache_purge_ip(target_ip);
  		IRELE(target_ip);
  	}
  	/*
  	 * Let interposed file systems know about removed links.
  	 */
  	if (target_ip_dropped)
  		IRELE(target_ip);
  
  	IRELE(src_ip);
  
  	/* Fall through to std_return with error = 0 or errno from
  	 * xfs_trans_commit	 */
  std_return:
  	if (DM_EVENT_ENABLED(src_dp, DM_EVENT_POSTRENAME) ||
  	    DM_EVENT_ENABLED(target_dp, DM_EVENT_POSTRENAME)) {
  		(void) XFS_SEND_NAMESP (mp, DM_EVENT_POSTRENAME,
  					src_dir_vp, DM_RIGHT_NULL,
  					target_dir_vp, DM_RIGHT_NULL,
  					src_name, target_name,
  					0, error, 0);
  	}
  	return error;
  
   abort_return:
  	cancel_flags |= XFS_TRANS_ABORT;
  	/* FALLTHROUGH */
   error_return:
  	xfs_bmap_cancel(&free_list);
  	xfs_trans_cancel(tp, cancel_flags);
  	goto std_return;
  
   rele_return:
  	IRELE(src_ip);
  	if (target_ip != NULL) {
  		IRELE(target_ip);
  	}
  	goto std_return;
  }
  