[Ocfs2-tools-devel] [PATCH 6/6] libocfs2: Detect stackglue and use it for all libo2dlm interaction.

[Sunil Mushran]

Signed-off-by: Sunil Mushran <sunil.mushran at oracle.com>


Joel Becker wrote:
> Now all ocfs2 tools will use libo2dlm+dlmfs for any stack that supports
> it.
>
> Signed-off-by: Joel Becker <joel.becker at oracle.com>
> ---
>  libocfs2/dlm.c |   20 +++++++++++++++-----
>  1 files changed, 15 insertions(+), 5 deletions(-)
>
> diff --git a/libocfs2/dlm.c b/libocfs2/dlm.c
> index 3a5015c..4c8cda8 100644
> --- a/libocfs2/dlm.c
> +++ b/libocfs2/dlm.c
> @@ -172,6 +172,7 @@ errcode_t ocfs2_initialize_dlm(ocfs2_filesys *fs, const char *service)
>  {
>  	struct o2dlm_ctxt *dlm_ctxt = NULL;
>  	errcode_t ret = 0;
> +	int stackglue_support;
>  	struct o2cb_cluster_desc cluster;
>  	struct o2cb_region_desc desc;
>  	char *stack_path;
> @@ -184,6 +185,10 @@ errcode_t ocfs2_initialize_dlm(ocfs2_filesys *fs, const char *service)
>  	if (ret)
>  		goto bail;
>  
> +	ret = o2dlm_supports_stackglue(&stackglue_support);
> +	if (ret)
> +		goto bail;
> +
>  	desc.r_service = (char *)service;
>  	desc.r_persist = 0;
>  	ret = o2cb_begin_group_join(&cluster, &desc);
> @@ -191,13 +196,18 @@ errcode_t ocfs2_initialize_dlm(ocfs2_filesys *fs, const char *service)
>  		goto bail;
>  
>  	/*
> -	 * NULL c_stack means o2cb, means use DLMFS, means
> -	 * pass DLMFS_PATH.  If we're using a userspace stack, pass NULL.
> +	 * We want to use dlmfs if we can, as it provides the full feature
> +	 * set of libo2dlm.  Any dlmfs with the 'stackglue' capability will
> +	 * support all cluster stacks.  An empty cluster.c_stack means
> +	 * o2cb, which always supports dlmfs.
> +	 *
> +	 * If we're unlucky enough to have older userspace stack code,
> +	 * we pass NULL to avoid dlmfs.
>  	 */
> -	if (cluster.c_stack)
> -		stack_path = NULL;
> -	else
> +	if (stackglue_support || !cluster.c_stack)
>  		stack_path = DEFAULT_DLMFS_PATH;
> +	else
> +		stack_path = NULL;
>  	ret = o2dlm_initialize(stack_path, fs->uuid_str, &dlm_ctxt);
>  	if (ret) {
>  		/* What to do with an error code? */
>