1. 根目录:
2. fs
3. xfs
4. 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_mount.h"
#include "xfs_trans.h"
#include "xfs_trans_priv.h"
#include "xfs_extfree_item.h"
#include "xfs_alloc.h"

/*
 * This routine is called to allocate an "extent free intention"
 * 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.
 */
xfs_efi_log_item_t *
xfs_trans_get_efi(xfs_trans_t	*tp,
		  uint		nextents)
{
	xfs_efi_log_item_t	*efip;

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

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

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

/*
 * This routine is called to indicate that the described
 * extent is to be logged as needing to be freed.  It should
 * be called once for each extent to be freed.
 */
void
xfs_trans_log_efi_extent(xfs_trans_t		*tp,
			 xfs_efi_log_item_t	*efip,
			 xfs_fsblock_t		start_block,
			 xfs_extlen_t		ext_len)
{
	uint			next_extent;
	xfs_extent_t		*extp;

	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 = start_block;
	extp->ext_len = ext_len;
}


/*
 * 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.
 */
xfs_efd_log_item_t *
xfs_trans_get_efd(xfs_trans_t		*tp,
		  xfs_efi_log_item_t	*efip,
		  uint			nextents)
{
	xfs_efd_log_item_t	*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)
{
	uint			next_extent;
	struct xfs_extent	*extp;
	int			error;

	error = xfs_free_extent(tp, start_block, ext_len);

	/*
	 * 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;
}