[Ocfs2-devel] [PATCH 2/3] Ocfs2: Change ocfs2_prepare_refcount_change_for_del() a bit to defer blocks reservation.

[TaoMa]

Hi Tristan,
    you'd better integrate this patch with patch 3/3. otherwise we can't 
build successfully if we apply this one and don't apply the next one(in 
some git bisect case).

Regards,
Tao
Tristan Ye wrote:
> As ocfs2_prepare_refcount_change_for_del() only called from ocfs2_commit_truncate for
> now(punching holes are going to use that soon I guess), we're safe to defer metadata
> blocks reservation unitl ocfs2_remove_btree_range(), who is also reserving blocks for
> extent btree adjusting, so it will be nice to do these in one go.
>
> Instead, it will return the blocks calculated to caller, to let him know how many extra
> blocks for refcount tree should be reserved next.
>
> Signed-off-by: Tristan Ye <tristan.ye at oracle.com>
> ---
>  fs/ocfs2/refcounttree.c |   21 +++++++--------------
>  fs/ocfs2/refcounttree.h |    2 +-
>  2 files changed, 8 insertions(+), 15 deletions(-)
>
> diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
> index 60287fc..42a8446 100644
> --- a/fs/ocfs2/refcounttree.c
> +++ b/fs/ocfs2/refcounttree.c
> @@ -2432,8 +2432,8 @@ out:
>   *
>   * Normally the refcount blocks store these refcount should be
>   * continguous also, so that we can get the number easily.
> - * As for meta_ac, we will at most add split 2 refcount record and
> - * 2 more refcount block, so just check it in a rough way.
> + * We will at most add split 2 refcount records and 2 more
> + * refcount block, so just check it in a rough way.
>   *
>   * Caller must hold refcount tree lock.
>   */
> @@ -2442,9 +2442,9 @@ int ocfs2_prepare_refcount_change_for_del(struct inode *inode,
>  					  u64 phys_blkno,
>  					  u32 clusters,
>  					  int *credits,
> -					  struct ocfs2_alloc_context **meta_ac)
> +					  int *ref_blocks)
>  {
> -	int ret, ref_blocks = 0;
> +	int ret;
>  	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
>  	struct ocfs2_inode_info *oi = OCFS2_I(inode);
>  	struct buffer_head *ref_root_bh = NULL;
> @@ -2480,21 +2480,14 @@ int ocfs2_prepare_refcount_change_for_del(struct inode *inode,
>  					       &tree->rf_ci,
>  					       ref_root_bh,
>  					       start_cpos, clusters,
> -					       &ref_blocks, credits);
> +					       ref_blocks, credits);
>  	if (ret) {
>  		mlog_errno(ret);
>  		goto out;
>  	}
>  
> -	mlog(0, "reserve new metadata %d, credits = %d\n",
> -	     ref_blocks, *credits);
> -
> -	if (ref_blocks) {
> -		ret = ocfs2_reserve_new_metadata_blocks(OCFS2_SB(inode->i_sb),
> -							ref_blocks, meta_ac);
> -		if (ret)
> -			mlog_errno(ret);
> -	}
> +	mlog(0, "reserve new metadata %d blocks, credits = %d\n",
> +	     *ref_blocks, *credits);
>  
>  out:
>  	brelse(ref_root_bh);
> diff --git a/fs/ocfs2/refcounttree.h b/fs/ocfs2/refcounttree.h
> index c1d19b1..f4bf110 100644
> --- a/fs/ocfs2/refcounttree.h
> +++ b/fs/ocfs2/refcounttree.h
> @@ -51,7 +51,7 @@ int ocfs2_prepare_refcount_change_for_del(struct inode *inode,
>  					  u64 phys_blkno,
>  					  u32 clusters,
>  					  int *credits,
> -					  struct ocfs2_alloc_context **meta_ac);
> +					  int *ref_blocks);
>  int ocfs2_refcount_cow(struct inode *inode, struct buffer_head *di_bh,
>  		       u32 cpos, u32 write_len, u32 max_cpos);
>  
>