[Ocfs2-devel] [PATCH] ocfs2: ensure journalaccess/journaldirty pairs don't cross journal restarting --ocfs2_rotate_subtree_left

[Xiaowei.hu <xiaowei.hu@oracle.com>]

How about this patch? Could anyone comment on it?


On 11/04/2011 11:59 AM, Wengang Wang wrote:
> journalaccess/journaldirty pairs shouldn't cross journal restarting.
> Function ocfs2_rotate_subtree_left() violates this rule. This patch tries
> to fix it.
>
> 1) adding a extra journal access before modifying the tree root. (see
> comment in patch it's self)
>
> 2) moving ocfs2_remove_empty_extent(left_leaf_el) priror, so that
> ocfs2_journal_dirty(handle, path_leaf_bh(left_path)) can take care of it.
> (before the change, seems there is a miss of not putting left_leaf_el to
> journal in del_right_subtree case.
>
> Signed-off-by: Wengang Wang<wen.gang.wang@oracle.com>
> ---
>   fs/ocfs2/alloc.c |   36 +++++++++++++++---------------------
>   1 files changed, 15 insertions(+), 21 deletions(-)
>
> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
> index ed553c6..ace7aa2 100644
> --- a/fs/ocfs2/alloc.c
> +++ b/fs/ocfs2/alloc.c
> @@ -2708,20 +2708,8 @@ static int ocfs2_rotate_subtree_left(handle_t *handle,
>   	}
>
>   	if (eb->h_next_leaf_blk == 0ULL&&
> -	    le16_to_cpu(right_leaf_el->l_next_free_rec) == 1) {
> -		/*
> -		 * We have to update i_last_eb_blk during the meta
> -		 * data delete.
> -		 */
> -		ret = ocfs2_et_root_journal_access(handle, et,
> -						   OCFS2_JOURNAL_ACCESS_WRITE);
> -		if (ret) {
> -			mlog_errno(ret);
> -			goto out;
> -		}
> -
> +	    le16_to_cpu(right_leaf_el->l_next_free_rec) == 1)
>   		del_right_subtree = 1;
> -	}
>
>   	/*
>   	 * Getting here with an empty extent in the right path implies
> @@ -2762,7 +2750,10 @@ static int ocfs2_rotate_subtree_left(handle_t *handle,
>   		ocfs2_rotate_leaf(left_leaf_el,&right_leaf_el->l_recs[0]);
>   		memset(&right_leaf_el->l_recs[0], 0,
>   		       sizeof(struct ocfs2_extent_rec));
> +	} else {
> +		ocfs2_remove_empty_extent(left_leaf_el);
>   	}
> +		
>   	if (eb->h_next_leaf_blk == 0ULL) {
>   		/*
>   		 * Move recs over to get rid of empty extent, decrease
> @@ -2786,17 +2777,20 @@ static int ocfs2_rotate_subtree_left(handle_t *handle,
>   			goto out;
>   		}
>
> -		eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
> -		ocfs2_et_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
> -
>   		/*
> -		 * Removal of the extent in the left leaf was skipped
> -		 * above so we could delete the right path
> -		 * 1st.
> +		 * journal can just restarted in ocfs2_update_edge_lengths.
> +		 * we have to re-access the tree root. We still has an credit
> +		 * reserved for the tree root.
>   		 */
> -		if (right_has_empty)
> -			ocfs2_remove_empty_extent(left_leaf_el);
> +		ret = ocfs2_et_root_journal_access(handle, et,
> +						   OCFS2_JOURNAL_ACCESS_WRITE);
> +		if (ret) {
> +			mlog_errno(ret);
> +			goto out;
> +		}
>
> +		eb = (struct ocfs2_extent_block *)path_leaf_bh(left_path)->b_data;
> +		ocfs2_et_set_last_eb_blk(et, le64_to_cpu(eb->h_blkno));
>   		ocfs2_journal_dirty(handle, et_root_bh);
>
>   		*deleted = 1;