path: root/fs/xfs/linux-2.6/xfs_sync.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 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_inode.h"
#include "xfs_dinode.h"
#include "xfs_error.h"
#include "xfs_filestream.h"
#include "xfs_vnodeops.h"
#include "xfs_inode_item.h"
#include "xfs_quota.h"
#include "xfs_trace.h"
#include "xfs_fsops.h"

#include <linux/kthread.h>
#include <linux/freezer.h>


STATIC xfs_inode_t *
xfs_inode_ag_lookup(
	struct xfs_mount	*mp,
	struct xfs_perag	*pag,
	uint32_t		*first_index,
	int			tag)
{
	int			nr_found;
	struct xfs_inode	*ip;

	/*
	 * use a gang lookup to find the next inode in the tree
	 * as the tree is sparse and a gang lookup walks to find
	 * the number of objects requested.
	 */
	if (tag == XFS_ICI_NO_TAG) {
		nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
				(void **)&ip, *first_index, 1);
	} else {
		nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root,
				(void **)&ip, *first_index, 1, tag);
	}
	if (!nr_found)
		return NULL;

	/*
	 * Update the index for the next lookup. Catch overflows
	 * into the next AG range which can occur if we have inodes
	 * in the last block of the AG and we are currently
	 * pointing to the last inode.
	 */
	*first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
	if (*first_index < XFS_INO_TO_AGINO(mp, ip->i_ino))
		return NULL;
	return ip;
}

STATIC int
xfs_inode_ag_walk(
	struct xfs_mount	*mp,
	struct xfs_perag	*pag,
	int			(*execute)(struct xfs_inode *ip,
					   struct xfs_perag *pag, int flags),
	int			flags,
	int			tag,
	int			exclusive,
	int			*nr_to_scan)
{
	uint32_t		first_index;
	int			last_error = 0;
	int			skipped;

restart:
	skipped = 0;
	first_index = 0;
	do {
		int		error = 0;
		xfs_inode_t	*ip;

		if (exclusive)
			write_lock(&pag->pag_ici_lock);
		else
			read_lock(&pag->pag_ici_lock);
		ip = xfs_inode_ag_lookup(mp, pag, &first_index, tag);
		if (!ip) {
			if (exclusive)
				write_unlock(&pag->pag_ici_lock);
			else
				read_unlock(&pag->pag_ici_lock);
			break;
		}

		/* execute releases pag->pag_ici_lock */
		error = execute(ip, pag, flags);
		if (error == EAGAIN) {
			skipped++;
			continue;
		}
		if (error)
			last_error = error;

		/* bail out if the filesystem is corrupted.  */
		if (error == EFSCORRUPTED)
			break;

	} while ((*nr_to_scan)--);

	if (skipped) {
		delay(1);
		goto restart;
	}
	return last_error;
}

/*
 * Select the next per-ag structure to iterate during the walk. The reclaim
 * walk is optimised only to walk AGs with reclaimable inodes in them.
 */
static struct xfs_perag *
xfs_inode_ag_iter_next_pag(
	struct xfs_mount	*mp,
	xfs_agnumber_t		*first,
	int			tag)
{
	struct xfs_perag	*pag = NULL;

	if (tag == XFS_ICI_RECLAIM_TAG) {
		int found;
		int ref;

		spin_lock(&mp->m_perag_lock);
		found = radix_tree_gang_lookup_tag(&mp->m_perag_tree,
				(void **)&pag, *first, 1, tag);
		if (found <= 0) {
			spin_unlock(&mp->m_perag_lock);
			return NULL;
		}
		*first = pag->pag_agno + 1;
		/* open coded pag reference increment */
		ref = atomic_inc_return(&pag->pag_ref);
		spin_unlock(&mp->m_perag_lock);
		trace_xfs_perag_get_reclaim(mp, pag->pag_agno, ref, _RET_IP_);
	} else {
		pag = xfs_perag_get(mp, *first);
		(*first)++;
	}
	return pag;
}

int
xfs_inode_ag_iterator(
	struct xfs_mount	*mp,
	int			(*execute)(struct xfs_inode *ip,
					   struct xfs_perag *pag, int flags),
	int			flags,
	int			tag,
	int			exclusive,
	int			*nr_to_scan)
{
	struct xfs_perag	*pag;
	int			error = 0;
	int			last_error = 0;
	xfs_agnumber_t		ag;
	int			nr;

	nr = nr_to_scan