path: root/fs/xfs/xfs_trans.c

/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * Copyright (C) 2010 Red Hat, 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_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_extent_busy.h"
#include "xfs_quota.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_log.h"
#include "xfs_trace.h"
#include "xfs_error.h"

kmem_zone_t	*xfs_trans_zone;
kmem_zone_t	*xfs_log_item_desc_zone;

/*
 * Initialize the precomputed transaction reservation values
 * in the mount structure.
 */
void
xfs_trans_init(
	struct xfs_mount	*mp)
{
	xfs_trans_resv_calc(mp, M_RES(mp));
}

/*
 * Free the transaction structure.  If there is more clean up
 * to do when the structure is freed, add it here.
 */
STATIC void
xfs_trans_free(
	struct xfs_trans	*tp)
{
	xfs_extent_busy_sort(&tp->t_busy);
	xfs_extent_busy_clear(tp->t_mountp, &tp->t_busy, false);

	atomic_dec(&tp->t_mountp->m_active_trans);
	if (!(tp->t_flags & XFS_TRANS_NO_WRITECOUNT))
		sb_end_intwrite(tp->t_mountp->m_super);
	xfs_trans_free_dqinfo(tp);
	kmem_zone_free(xfs_trans_zone, tp);
}

/*
 * This is called to create a new transaction which will share the
 * permanent log reservation of the given transaction.  The remaining
 * unused block and rt extent reservations are also inherited.  This
 * implies that the original transaction is no longer allowed to allocate
 * blocks.  Locks and log items, however, are no inherited.  They must
 * be added to the new transaction explicitly.
 */
STATIC xfs_trans_t *
xfs_trans_dup(
	xfs_trans_t	*tp)
{
	xfs_trans_t	*ntp;

	ntp = kmem_zone_zalloc(xfs_trans_zone, KM_SLEEP);

	/*
	 * Initialize the new transaction structure.
	 */
	ntp->t_magic = XFS_TRANS_HEADER_MAGIC;
	ntp->t_mountp = tp->t_mountp;
	INIT_LIST_HEAD(&ntp->t_items);
	INIT_LIST_HEAD(&ntp->t_busy);

	ASSERT(tp->t_flags & XFS_TRANS_PERM_LOG_RES);
	ASSERT(tp->t_ticket != NULL);

	ntp->t_flags = XFS_TRANS_PERM_LOG_RES |
		       (tp->t_flags & XFS_TRANS_RESERVE) |
		       (tp->t_flags & XFS_TRANS_NO_WRITECOUNT);
	/* We gave our writer reference to the new transaction */
	tp->t_flags |= XFS_TRANS_NO_WRITECOUNT;
	ntp->t_ticket = xfs_log_ticket_get(tp->t_ticket);
	ntp->t_blk_res = tp->t_blk_res - tp->t_blk_res_used;
	tp->t_blk_res = tp->t_blk_res_used;
	ntp->t_rtx_res = tp->t_rtx_res - tp->t_rtx_res_used;
	tp->t_rtx_res = tp->t_rtx_res_used;
	ntp->t_pflags = tp->t_pflags;

	xfs_trans_dup_dqinfo(tp, ntp);

	atomic_inc(&tp->t_mountp->m_active_trans);
	return ntp;
}

/*
 * This is called to reserve free disk blocks and log space for the
 * given transaction.  This must be done before allocating any resources
 * within the transaction.
 *
 * This will return ENOSPC if there are not enough blocks available.
 * It will sleep waiting for available log space.
 * The only valid value for the flags parameter is XFS_RES_LOG_PERM, which
 * is used by long running transactions.  If any one of the reservations
 * fails then they will all be backed out.
 *
 * This does not do quota reservations. That typically is done by the
 * caller afterwards.
 */
static int
xfs_trans_reserve(
	struct xfs_trans	*tp,
	struct xfs_trans_res	*resp,
	uint			blocks,
	uint			rtextents)
{
	int		error = 0;
	bool		rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;

	/* Mark this thread as being in a transaction */
	current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);

	/*
	 * Attempt to reserve the needed disk blocks by decrementing
	 * the number needed from the number available.  This will
	 * fail if the count would go below zero.
	 */
	if (blocks > 0) {
		error = xfs_mod_fdblocks(tp->t_mountp, -((int64_t)blocks), rsvd);
		if (error != 0) {
			current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
			return -ENOSPC;
		}
		tp->t_blk_res += blocks;
	}

	/*
	 * Reserve the log space needed for this transaction.
	 */
	if (resp->tr_logres > 0) {
		bool	permanent = false;

		ASSERT(tp->t_log_res == 0 ||
		       tp->t_log_res == resp->tr_logres);
		ASSERT(tp->t_log_count == 0 ||
		       tp->t_log_count == resp->tr_logcount);

		if (resp->tr_logflags & XFS_TRANS_PERM_LOG_RES) {
			tp->t_flags |= XFS_TRANS_PERM_LOG_RES;
			permanent = true;
		} else {
			ASSERT(tp->t_ticket == NULL);
			ASSERT(!(tp->t_flags & XFS_TRANS_PERM_LOG_RES));
		}

		if (tp->t_ticket != NULL) {
			ASSERT(resp->tr_logflags & XFS_TRANS_PERM_LOG_RES);
			error = xfs_log_regrant(tp->t_mountp, tp->t_ticket);
		} else {
			error = xfs_log_reserve(tp->t_mountp,
						resp->tr_logres,
						resp->tr_logcount,
						&tp->t_ticket, XFS_TRANSACTION,
						permanent);