alistair23-linux/fs/xfs/xfs_trans_extfree.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_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_extfree_item.h"
#include "xfs_alloc.h"
#include "xfs_bmap.h"
#include "xfs_trace.h"

/*
 * This routine is called to allocate an "extent free done"
 * log item that will hold nextents worth of extents.  The
 * caller must use all nextents extents, because we are not
 * flexible about this at all.
 */
struct xfs_efd_log_item *
xfs_trans_get_efd(struct xfs_trans		*tp,
		  struct xfs_efi_log_item	*efip,
		  uint				nextents)
{
	struct xfs_efd_log_item			*efdp;

	ASSERT(tp != NULL);
	ASSERT(nextents > 0);

	efdp = xfs_efd_init(tp->t_mountp, efip, nextents);
	ASSERT(efdp != NULL);

	/*
	 * Get a log_item_desc to point at the new item.
	 */
	xfs_trans_add_item(tp, &efdp->efd_item);
	return efdp;
}

/*
 * Free an extent and log it to the EFD. Note that the transaction is marked
 * dirty regardless of whether the extent free succeeds or fails to support the
 * EFI/EFD lifecycle rules.
 */
int
xfs_trans_free_extent(
	struct xfs_trans	*tp,
	struct xfs_efd_log_item	*efdp,
	xfs_fsblock_t		start_block,
	xfs_extlen_t		ext_len,
	struct xfs_owner_info	*oinfo)
{
	struct xfs_mount	*mp = tp->t_mountp;
	uint			next_extent;
	xfs_agnumber_t		agno = XFS_FSB_TO_AGNO(mp, start_block);
	xfs_agblock_t		agbno = XFS_FSB_TO_AGBNO(mp, start_block);
	struct xfs_extent	*extp;
	int			error;

	trace_xfs_bmap_free_deferred(tp->t_mountp, agno, 0, agbno, ext_len);

	error = xfs_free_extent(tp, start_block, ext_len, oinfo,
			XFS_AG_RESV_NONE);

	/*
	 * Mark the transaction dirty, even on error. This ensures the
	 * transaction is aborted, which:
	 *
	 * 1.) releases the EFI and frees the EFD
	 * 2.) shuts down the filesystem
	 */
	tp->t_flags |= XFS_TRANS_DIRTY;
	efdp->efd_item.li_desc->lid_flags |= XFS_LID_DIRTY;

	next_extent = efdp->efd_next_extent;
	ASSERT(next_extent < efdp->efd_format.efd_nextents);
	extp = &(efdp->efd_format.efd_extents[next_extent]);
	extp->ext_start = start_block;
	extp->ext_len = ext_len;
	efdp->efd_next_extent++;

	return error;
}

/* Sort bmap items by AG. */
static int
xfs_extent_free_diff_items(
	void				*priv,
	struct list_head		*a,
	struct list_head		*b)
{
	struct xfs_mount		*mp = priv;
	struct xfs_extent_free_item	*ra;
	struct xfs_extent_free_item	*rb;

	ra = container_of(a, struct xfs_extent_free_item, xefi_list);
	rb = container_of(b, struct xfs_extent_free_item, xefi_list);
	return  XFS_FSB_TO_AGNO(mp, ra->xefi_startblock) -
		XFS_FSB_TO_AGNO(mp, rb->xefi_startblock);
}

/* Get an EFI. */
STATIC void *
xfs_extent_free_create_intent(
	struct xfs_trans		*tp,
	unsigned int			count)
{
	struct xfs_efi_log_item		*efip;

	ASSERT(tp != NULL);
	ASSERT(count > 0);

	efip = xfs_efi_init(tp->t_mountp, count);
	ASSERT(efip != NULL);

	/*
	 * Get a log_item_desc to point at the new item.
	 */
	xfs_trans_add_item(tp, &efip->efi_item);
	return efip;
}

/* Log a free extent to the intent item. */
STATIC void
xfs_extent_free_log_item(
	struct xfs_trans		*tp,
	void				*intent,
	struct list_head		*item)
{
	struct xfs_efi_log_item		*efip = intent;
	struct xfs_extent_free_item	*free;
	uint				next_extent;
	struct xfs_extent		*extp;

	free = container_of(item, struct xfs_extent_free_item, xefi_list);

	tp->t_flags |= XFS_TRANS_DIRTY;
	efip->efi_item.li_desc->lid_flags |= XFS_LID_DIRTY;

	/*
	 * atomic_inc_return gives us the value after the increment;
	 * we want to use it as an array index so we need to subtract 1 from
	 * it.
	 */
	next_extent = atomic_inc_return(&efip->efi_next_extent) - 1;
	ASSERT(next_extent < efip->efi_format.efi_nextents);
	extp = &efip->efi_format.efi_extents[next_extent];
	extp->ext_start = free->xefi_startblock;
	extp->ext_len = free->xefi_blockcount;
}

/* Get an EFD so we can process all the free extents. */
STATIC void *
xfs_extent_free_create_done(
	struct xfs_trans		*tp,
	void				*intent,
	unsigned int			count)
{
	return xfs_trans_get_efd(tp, intent, count);
}

/* Process a free extent. */
STATIC int
xfs_extent_free_finish_item(
	struct xfs_trans		*tp,
	struct xfs_defer_ops		*dop,
	struct list_head		*item,
	void				*done_item,
	void				**state)
{
	struct xfs_extent_free_item	*free;
	int				error;

	free = container_of(item, struct xfs_extent_free_item, xefi_list);
	error = xfs_trans_free_extent(tp, done_item,
			free->xefi_startblock,
			free->xefi_blockcount,
			&free->xefi_oinfo);
	kmem_free(free);
	return error;
}

/* Abort all pending EFIs. */
STATIC void
xfs_extent_free_abort_intent(
	void				*intent)
{
	xfs_efi_release(intent);
}

/* Cancel a free extent. */
STATIC void
xfs_extent_free_cancel_item(
	struct list_head		*item)
{
	struct xfs_extent_free_item	*free;

	free = container_of(item, struct xfs_extent_free_item, xefi_list);
	kmem_free(free);
}

static const struct xfs_defer_op_type xfs_extent_free_defer_type = {
	.type		= XFS_DEFER_OPS_TYPE_FREE,
	.max_items	= XFS_EFI_MAX_FAST_EXTENTS,
	.diff_items	= xfs_extent_free_diff_items,
	.create_intent	= xfs_extent_free_create_intent,
	.abort_intent	= xfs_extent_free_abort_intent,
	.log_item	= xfs_extent_free_log_item,
	.create_done	= xfs_extent_free_create_done,
	.finish_item	= xfs_extent_free_finish_item,
	.cancel_item	= xfs_extent_free_cancel_item,
};

/* Register the deferred op type. */
void
xfs_extent_free_init_defer_op(void)
{
	xfs_defer_init_op_type(&xfs_extent_free_defer_type);
}