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8341897882
The extent map code was ripped out earlier because of an inability to deal with holes. This patch adds back a simpler caching scheme requiring far less code. Our old extent map caching was designed back when meta data block caching in Ocfs2 didn't work very well, resulting in many disk reads. These days our metadata caching is much better, resulting in no un-necessary disk reads. As a result, extent caching doesn't have to be as fancy, nor does it have to cache as many extents. Keeping the last 3 extents seen should be sufficient to give us a small performance boost on some streaming workloads. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
53 lines
1.7 KiB
C
53 lines
1.7 KiB
C
/* -*- mode: c; c-basic-offset: 8; -*-
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* vim: noexpandtab sw=8 ts=8 sts=0:
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*
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* extent_map.h
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*
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* In-memory file extent mappings for OCFS2.
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*
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* Copyright (C) 2004 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License, version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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#ifndef _EXTENT_MAP_H
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#define _EXTENT_MAP_H
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struct ocfs2_extent_map_item {
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unsigned int ei_cpos;
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unsigned int ei_phys;
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unsigned int ei_clusters;
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unsigned int ei_flags;
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struct list_head ei_list;
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};
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#define OCFS2_MAX_EXTENT_MAP_ITEMS 3
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struct ocfs2_extent_map {
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unsigned int em_num_items;
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struct list_head em_list;
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};
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void ocfs2_extent_map_init(struct inode *inode);
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void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cluster);
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void ocfs2_extent_map_insert_rec(struct inode *inode,
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struct ocfs2_extent_rec *rec);
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int ocfs2_get_clusters(struct inode *inode, u32 v_cluster, u32 *p_cluster,
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u32 *num_clusters, unsigned int *extent_flags);
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int ocfs2_extent_map_get_blocks(struct inode *inode, u64 v_blkno, u64 *p_blkno,
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u64 *ret_count, unsigned int *extent_flags);
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#endif /* _EXTENT_MAP_H */
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