linux/fs/xfs/xfs_trans_extfree.c
Christoph Hellwig e98c414f9a xfs: simplify log item descriptor tracking
Currently we track log item descriptor belonging to a transaction using a
complex opencoded chunk allocator.  This code has been there since day one
and seems to work around the lack of an efficient slab allocator.

This patch replaces it with dynamically allocated log item descriptors
from a dedicated slab pool, linked to the transaction by a linked list.

This allows to greatly simplify the log item descriptor tracking to the
point where it's just a couple hundred lines in xfs_trans.c instead of
a separate file.  The external API has also been simplified while we're
at it - the xfs_trans_add_item and xfs_trans_del_item functions to add/
delete items from a transaction have been simplified to the bare minium,
and the xfs_trans_find_item function is replaced with a direct dereference
of the li_desc field.  All debug code walking the list of log items in
a transaction is down to a simple list_for_each_entry.

Note that we could easily use a singly linked list here instead of the
double linked list from list.h as the fastpath only does deletion from
sequential traversal.  But given that we don't have one available as
a library function yet I use the list.h functions for simplicity.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-07-26 13:16:34 -05:00

130 lines
3.4 KiB
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_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_trans_priv.h"
#include "xfs_extfree_item.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;
next_extent = efip->efi_next_extent;
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;
efip->efi_next_extent++;
}
/*
* 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;
}
/*
* This routine is called to indicate that the described
* extent is to be logged as having been freed. It should
* be called once for each extent freed.
*/
void
xfs_trans_log_efd_extent(xfs_trans_t *tp,
xfs_efd_log_item_t *efdp,
xfs_fsblock_t start_block,
xfs_extlen_t ext_len)
{
uint next_extent;
xfs_extent_t *extp;
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++;
}