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linux-next/fs/ocfs2/suballoc.h
Mark Fasheh d02f00cc05 ocfs2: allocation reservations
This patch improves Ocfs2 allocation policy by allowing an inode to
reserve a portion of the local alloc bitmap for itself. The reserved
portion (allocation window) is advisory in that other allocation
windows might steal it if the local alloc bitmap becomes
full. Otherwise, the reservations are honored and guaranteed to be
free. When the local alloc window is moved to a different portion of
the bitmap, existing reservations are discarded.

Reservation windows are represented internally by a red-black
tree. Within that tree, each node represents the reservation window of
one inode. An LRU of active reservations is also maintained. When new
data is written, we allocate it from the inodes window. When all bits
in a window are exhausted, we allocate a new one as close to the
previous one as possible. Should we not find free space, an existing
reservation is pulled off the LRU and cannibalized.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>
2010-05-05 18:17:30 -07:00

201 lines
6.5 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_
struct ocfs2_suballoc_result;
typedef int (group_search_t)(struct inode *,
struct buffer_head *,
u32, /* bits_wanted */
u32, /* min_bits */
u64, /* max_block */
struct ocfs2_suballoc_result *);
/* found bits */
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 */
struct ocfs2_alloc_reservation *ac_resv;
};
void ocfs2_init_steal_slots(struct ocfs2_super *osb);
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(handle_t *handle,
struct ocfs2_alloc_context *ac,
u32 bits_wanted,
u64 *suballoc_loc,
u16 *suballoc_bit_start,
u32 *num_bits,
u64 *blkno_start);
int ocfs2_claim_new_inode(handle_t *handle,
struct inode *dir,
struct buffer_head *parent_fe_bh,
struct ocfs2_alloc_context *ac,
u64 *suballoc_loc,
u16 *suballoc_bit,
u64 *fe_blkno);
int ocfs2_claim_clusters(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(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);
int ocfs2_release_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);
int ocfs2_test_inode_bit(struct ocfs2_super *osb, u64 blkno, int *res);
#endif /* _CHAINALLOC_H_ */