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linux/fs/ocfs2/suballoc.h
Tao Ma 138211515c ocfs2: Optimize inode allocation by remembering last group
In ocfs2, the inode block search looks for the "emptiest" inode
group to allocate from. So if an inode alloc file has many equally
(or almost equally) empty groups, new inodes will tend to get
spread out amongst them, which in turn can put them all over the
disk. This is undesirable because directory operations on conceptually
"nearby" inodes force a large number of seeks.

So we add ip_last_used_group in core directory inodes which records
the last used allocation group. Another field named ip_last_used_slot
is also added in case inode stealing happens. When claiming new inode,
we passed in directory's inode so that the allocation can use this
information.
For more details, please see
http://oss.oracle.com/osswiki/OCFS2/DesignDocs/InodeAllocationStrategy.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2009-04-03 11:39:17 -07:00

192 lines
6.3 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* suballoc.h
*
* Defines sub allocator api
*
* Copyright (C) 2003, 2004 Oracle. 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; either
* version 2 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will 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 to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#ifndef _CHAINALLOC_H_
#define _CHAINALLOC_H_
typedef int (group_search_t)(struct inode *,
struct buffer_head *,
u32, /* bits_wanted */
u32, /* min_bits */
u64, /* max_block */
u16 *, /* *bit_off */
u16 *); /* *bits_found */
struct ocfs2_alloc_context {
struct inode *ac_inode; /* which bitmap are we allocating from? */
struct buffer_head *ac_bh; /* file entry bh */
u32 ac_alloc_slot; /* which slot are we allocating from? */
u32 ac_bits_wanted;
u32 ac_bits_given;
#define OCFS2_AC_USE_LOCAL 1
#define OCFS2_AC_USE_MAIN 2
#define OCFS2_AC_USE_INODE 3
#define OCFS2_AC_USE_META 4
u32 ac_which;
/* these are used by the chain search */
u16 ac_chain;
int ac_allow_chain_relink;
group_search_t *ac_group_search;
u64 ac_last_group;
u64 ac_max_block; /* Highest block number to allocate. 0 is
is the same as ~0 - unlimited */
};
void ocfs2_free_alloc_context(struct ocfs2_alloc_context *ac);
static inline int ocfs2_alloc_context_bits_left(struct ocfs2_alloc_context *ac)
{
return ac->ac_bits_wanted - ac->ac_bits_given;
}
/*
* Please note that the caller must make sure that root_el is the root
* of extent tree. So for an inode, it should be &fe->id2.i_list. Otherwise
* the result may be wrong.
*/
int ocfs2_reserve_new_metadata(struct ocfs2_super *osb,
struct ocfs2_extent_list *root_el,
struct ocfs2_alloc_context **ac);
int ocfs2_reserve_new_metadata_blocks(struct ocfs2_super *osb,
int blocks,
struct ocfs2_alloc_context **ac);
int ocfs2_reserve_new_inode(struct ocfs2_super *osb,
struct ocfs2_alloc_context **ac);
int ocfs2_reserve_clusters(struct ocfs2_super *osb,
u32 bits_wanted,
struct ocfs2_alloc_context **ac);
int ocfs2_claim_metadata(struct ocfs2_super *osb,
handle_t *handle,
struct ocfs2_alloc_context *ac,
u32 bits_wanted,
u16 *suballoc_bit_start,
u32 *num_bits,
u64 *blkno_start);
int ocfs2_claim_new_inode(struct ocfs2_super *osb,
handle_t *handle,
struct inode *dir,
struct buffer_head *parent_fe_bh,
struct ocfs2_alloc_context *ac,
u16 *suballoc_bit,
u64 *fe_blkno);
int ocfs2_claim_clusters(struct ocfs2_super *osb,
handle_t *handle,
struct ocfs2_alloc_context *ac,
u32 min_clusters,
u32 *cluster_start,
u32 *num_clusters);
/*
* Use this variant of ocfs2_claim_clusters to specify a maxiumum
* number of clusters smaller than the allocation reserved.
*/
int __ocfs2_claim_clusters(struct ocfs2_super *osb,
handle_t *handle,
struct ocfs2_alloc_context *ac,
u32 min_clusters,
u32 max_clusters,
u32 *cluster_start,
u32 *num_clusters);
int ocfs2_free_suballoc_bits(handle_t *handle,
struct inode *alloc_inode,
struct buffer_head *alloc_bh,
unsigned int start_bit,
u64 bg_blkno,
unsigned int count);
int ocfs2_free_dinode(handle_t *handle,
struct inode *inode_alloc_inode,
struct buffer_head *inode_alloc_bh,
struct ocfs2_dinode *di);
int ocfs2_free_clusters(handle_t *handle,
struct inode *bitmap_inode,
struct buffer_head *bitmap_bh,
u64 start_blk,
unsigned int num_clusters);
static inline u64 ocfs2_which_suballoc_group(u64 block, unsigned int bit)
{
u64 group = block - (u64) bit;
return group;
}
static inline u32 ocfs2_cluster_from_desc(struct ocfs2_super *osb,
u64 bg_blkno)
{
/* This should work for all block group descriptors as only
* the 1st group descriptor of the cluster bitmap is
* different. */
if (bg_blkno == osb->first_cluster_group_blkno)
return 0;
/* the rest of the block groups are located at the beginning
* of their 1st cluster, so a direct translation just
* works. */
return ocfs2_blocks_to_clusters(osb->sb, bg_blkno);
}
static inline int ocfs2_is_cluster_bitmap(struct inode *inode)
{
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
return osb->bitmap_blkno == OCFS2_I(inode)->ip_blkno;
}
/* This is for local alloc ONLY. Others should use the task-specific
* apis above. */
int ocfs2_reserve_cluster_bitmap_bits(struct ocfs2_super *osb,
struct ocfs2_alloc_context *ac);
void ocfs2_free_ac_resource(struct ocfs2_alloc_context *ac);
/* given a cluster offset, calculate which block group it belongs to
* and return that block offset. */
u64 ocfs2_which_cluster_group(struct inode *inode, u32 cluster);
/*
* By default, ocfs2_read_group_descriptor() calls ocfs2_error() when it
* finds a problem. A caller that wants to check a group descriptor
* without going readonly should read the block with ocfs2_read_block[s]()
* and then checking it with this function. This is only resize, really.
* Everyone else should be using ocfs2_read_group_descriptor().
*/
int ocfs2_check_group_descriptor(struct super_block *sb,
struct ocfs2_dinode *di,
struct buffer_head *bh);
/*
* Read a group descriptor block into *bh. If *bh is NULL, a bh will be
* allocated. This is a cached read. The descriptor will be validated with
* ocfs2_validate_group_descriptor().
*/
int ocfs2_read_group_descriptor(struct inode *inode, struct ocfs2_dinode *di,
u64 gd_blkno, struct buffer_head **bh);
int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_extent_tree *et,
u32 clusters_to_add, u32 extents_to_split,
struct ocfs2_alloc_context **data_ac,
struct ocfs2_alloc_context **meta_ac);
#endif /* _CHAINALLOC_H_ */