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linux/fs/ocfs2/refcounttree.h
Tristan Ye 78f94673d7 Ocfs2: Optimize ocfs2 truncate to use ocfs2_remove_btree_range() instead.
Truncate is just a special case of punching holes(from new i_size to
end), we therefore could take advantage of the existing
ocfs2_remove_btree_range() to reduce the comlexity and redundancy in
alloc.c.  The goal here is to make truncate more generic and
straightforward.

Several functions only used by ocfs2_commit_truncate() will smiply be
removed.

ocfs2_remove_btree_range() was originally used by the hole punching
code, which didn't take refcount trees into account (definitely a bug).
We therefore need to change that func a bit to handle refcount trees.
It must take the refcount lock, calculate and reserve blocks for
refcount tree changes, and decrease refcounts at the end.  We replace 
ocfs2_lock_allocators() here by adding a new func
ocfs2_reserve_blocks_for_rec_trunc() which accepts some extra blocks to
reserve.  This will not hurt any other code using
ocfs2_remove_btree_range() (such as dir truncate and hole punching).

I merged the following steps into one patch since they may be
logically doing one thing, though I know it looks a little bit fat
to review.

1). Remove redundant code used by ocfs2_commit_truncate(), since we're
    moving to ocfs2_remove_btree_range anyway.

2). Add a new func ocfs2_reserve_blocks_for_rec_trunc() for purpose of
    accepting some extra blocks to reserve.

3). Change ocfs2_prepare_refcount_change_for_del() a bit to fit our
    needs.  It's safe to do this since it's only being called by
    truncate.

4). Change ocfs2_remove_btree_range() a bit to take refcount case into
    account.

5). Finally, we change ocfs2_commit_truncate() to call
    ocfs2_remove_btree_range() in a proper way.

The patch has been tested normally for sanity check, stress tests
with heavier workload will be expected.

Based on this patch, fixing the punching holes bug will be fairly easy.

Signed-off-by: Tristan Ye <tristan.ye@oracle.com>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-05-18 12:25:10 -07:00

107 lines
3.7 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* refcounttree.h
*
* Copyright (C) 2009 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 version 2 as published by the Free Software Foundation.
*
* 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.
*/
#ifndef OCFS2_REFCOUNTTREE_H
#define OCFS2_REFCOUNTTREE_H
struct ocfs2_refcount_tree {
struct rb_node rf_node;
u64 rf_blkno;
u32 rf_generation;
struct rw_semaphore rf_sem;
struct ocfs2_lock_res rf_lockres;
struct kref rf_getcnt;
int rf_removed;
/* the following 4 fields are used by caching_info. */
struct ocfs2_caching_info rf_ci;
spinlock_t rf_lock;
struct mutex rf_io_mutex;
struct super_block *rf_sb;
};
void ocfs2_purge_refcount_trees(struct ocfs2_super *osb);
int ocfs2_lock_refcount_tree(struct ocfs2_super *osb, u64 ref_blkno, int rw,
struct ocfs2_refcount_tree **tree,
struct buffer_head **ref_bh);
void ocfs2_unlock_refcount_tree(struct ocfs2_super *osb,
struct ocfs2_refcount_tree *tree,
int rw);
int ocfs2_decrease_refcount(struct inode *inode,
handle_t *handle, u32 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc,
int delete);
int ocfs2_prepare_refcount_change_for_del(struct inode *inode,
u64 refcount_loc,
u64 phys_blkno,
u32 clusters,
int *credits,
int *ref_blocks);
int ocfs2_refcount_cow(struct inode *inode, struct buffer_head *di_bh,
u32 cpos, u32 write_len, u32 max_cpos);
typedef int (ocfs2_post_refcount_func)(struct inode *inode,
handle_t *handle,
void *para);
/*
* Some refcount caller need to do more work after we modify the data b-tree
* during refcount operation(including CoW and add refcount flag), and make the
* transaction complete. So it must give us this structure so that we can do it
* within our transaction.
*
*/
struct ocfs2_post_refcount {
int credits; /* credits it need for journal. */
ocfs2_post_refcount_func *func; /* real function. */
void *para;
};
int ocfs2_refcounted_xattr_delete_need(struct inode *inode,
struct ocfs2_caching_info *ref_ci,
struct buffer_head *ref_root_bh,
struct ocfs2_xattr_value_root *xv,
int *meta_add, int *credits);
int ocfs2_refcount_cow_xattr(struct inode *inode,
struct ocfs2_dinode *di,
struct ocfs2_xattr_value_buf *vb,
struct ocfs2_refcount_tree *ref_tree,
struct buffer_head *ref_root_bh,
u32 cpos, u32 write_len,
struct ocfs2_post_refcount *post);
int ocfs2_add_refcount_flag(struct inode *inode,
struct ocfs2_extent_tree *data_et,
struct ocfs2_caching_info *ref_ci,
struct buffer_head *ref_root_bh,
u32 cpos, u32 p_cluster, u32 num_clusters,
struct ocfs2_cached_dealloc_ctxt *dealloc,
struct ocfs2_post_refcount *post);
int ocfs2_remove_refcount_tree(struct inode *inode, struct buffer_head *di_bh);
int ocfs2_try_remove_refcount_tree(struct inode *inode,
struct buffer_head *di_bh);
int ocfs2_increase_refcount(handle_t *handle,
struct ocfs2_caching_info *ci,
struct buffer_head *ref_root_bh,
u64 cpos, u32 len,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc);
int ocfs2_reflink_ioctl(struct inode *inode,
const char __user *oldname,
const char __user *newname,
bool preserve);
#endif /* OCFS2_REFCOUNTTREE_H */