xfs_rename.c

linux 内核源代码

/*
 * 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