path: root/fs/xfs/xfs_iget.c

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 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.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */

#include <linux/delay.h>

#include "xfs.h"

#include "xfs_macros.h"
#include "xfs_types.h"
#include "xfs_inum.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_alloc_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_attr_sf.h"
#include "xfs_dir_sf.h"
#include "xfs_dir2_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_quota.h"
#include "xfs_utils.h"
#include "xfs_bit.h"

/*
 * Initialize the inode hash table for the newly mounted file system.
 * Choose an initial table size based on user specified value, else
 * use a simple algorithm using the maximum number of inodes as an
 * indicator for table size, and clamp it between one and some large
 * number of pages.
 */
void
xfs_ihash_init(xfs_mount_t *mp)
{
	__uint64_t	icount;
	uint		i, flags = KM_SLEEP | KM_MAYFAIL;

	if (!mp->m_ihsize) {
		icount = mp->m_maxicount ? mp->m_maxicount :
			 (mp->m_sb.sb_dblocks << mp->m_sb.sb_inopblog);
		mp->m_ihsize = 1 << max_t(uint, 8,
					(xfs_highbit64(icount) + 1) / 2);
		mp->m_ihsize = min_t(uint, mp->m_ihsize,
					(64 * NBPP) / sizeof(xfs_ihash_t));
	}

	while (!(mp->m_ihash = (xfs_ihash_t *)kmem_zalloc(mp->m_ihsize *
						sizeof(xfs_ihash_t), flags))) {
		if ((mp->m_ihsize >>= 1) <= NBPP)
			flags = KM_SLEEP;
	}
	for (i = 0; i < mp->m_ihsize; i++) {
		rwlock_init(&(mp->m_ihash[i].ih_lock));
	}
}

/*
 * Free up structures allocated by xfs_ihash_init, at unmount time.
 */
void
xfs_ihash_free(xfs_mount_t *mp)
{
	kmem_free(mp->m_ihash, mp->m_ihsize*sizeof(xfs_ihash_t));
	mp->m_ihash = NULL;
}

/*
 * Initialize the inode cluster hash table for the newly mounted file system.
 * Its size is derived from the ihash table size.
 */
void
xfs_chash_init(xfs_mount_t *mp)
{
	uint	i;

	mp->m_chsize = max_t(uint, 1, mp->m_ihsize /
			 (XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog));
	mp->m_chsize = min_t(uint, mp->m_chsize, mp->m_ihsize);
	mp->m_chash = (xfs_chash_t *)kmem_zalloc(mp->m_chsize
						 * sizeof(xfs_chash_t),
						 KM_SLEEP);
	for (i = 0; i < mp->m_chsize; i++) {
		spinlock_init(&mp->m_chash[i].ch_lock,"xfshash");
	}
}

/*
 * Free up structures allocated by xfs_chash_init, at unmount time.
 */
void
xfs_chash_free(xfs_mount_t *mp)
{
	int	i;

	for (i = 0; i < mp->m_chsize; i++) {
		spinlock_destroy(&mp->m_chash[i].ch_lock);
	}

	kmem_free(mp->m_chash, mp->m_chsize*sizeof(xfs_chash_t));
	mp->m_chash = NULL;
}

/*
 * Try to move an inode to the front of its hash list if possible
 * (and if its not there already).  Called right after obtaining
 * the list version number and then dropping the read_lock on the
 * hash list in question (which is done right after looking up the
 * inode in question...).
 */
STATIC void
xfs_ihash_promote(
	xfs_ihash_t	*ih,
	xfs_inode_t	*ip,
	ulong		version)
{
	xfs_inode_t	*iq;

	if ((ip->i_prevp != &ih->ih_next) && write_trylock(&ih->ih_lock)) {
		if (likely(version == ih->ih_version)) {