[Ocfs2-devel] [PATCH 04/39] ocfs2: Basic tree root operation.

[Joel Becker]

On Thu, Apr 30, 2009 at 06:58:16AM +0800, Tao Ma wrote:
> diff --git a/fs/ocfs2/journal.h b/fs/ocfs2/journal.h
> index 08196e0..bfd5942 100644
> --- a/fs/ocfs2/journal.h
> +++ b/fs/ocfs2/journal.h
> @@ -482,6 +482,9 @@ static inline int ocfs2_calc_dxi_expand_credits(struct super_block *sb)
>  	return credits;
>  }
>  
> +#define OCFS2_REFCOUNT_TREE_CREATE_CREDITS (OCFS2_INODE_UPDATE_CREDITS + \
> +					    + OCFS2_SUBALLOC_ALLOC + 1)
> +#define OCFS2_REFCOUNT_TREE_SET_CREDITS (OCFS2_INODE_UPDATE_CREDITS + 1)

	Please put comments on these credits defines.  We want to know
what each credit is for.

> +	BUG_ON(oi->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL);
> +	BUG_ON(di->i_refcount_loc);

	Don't BUG_ON(di->i_refcount_loc).  That's an on-disk structure
that could be garbage, and there's no point in crashing becasue of it.
We actually don't care if it is zero, because we know we're safe to
attach the new refcount tree.  The same goes for set_tree.

> +	rb = (struct ocfs2_refcount_block *)ref_root_bh->b_data;
> +	le32_add_cpu(&rb->rf_count, 1);

	I see you have no locking for the refcount tree right now
(spinlock or cluster lock).  I assume that's coming in a later patch.

> +int ocfs2_remove_refcount_tree(struct inode *inode, struct buffer_head *di_bh)
> +{
> +	int ret;
> +	handle_t *handle = NULL;
> +	struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
> +	struct ocfs2_inode_info *oi = OCFS2_I(inode);
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
> +	struct ocfs2_refcount_block *rb;
> +	struct inode *alloc_inode = NULL;
> +	struct buffer_head *alloc_bh = NULL;
> +	struct buffer_head *blk_bh = NULL;
> +	int credits = OCFS2_INODE_UPDATE_CREDITS + 1;

	This should be an OCFS2_REFCOUNT_TREE_REMOVE_CREDITS define,
with appropriate comment.

Joel

-- 

"For every complex problem there exists a solution that is brief,
     concise, and totally wrong."
                                        -Unknown

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127