Re: [Ocfs2-devel] [PATCH 11/11] ocfs2_dlmfs: Enable the use of user cluster stacks.

[Sunil Mushran <sunil.mushran@oracle.com>]

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


Joel Becker wrote:
> Unlike ocfs2, dlmfs has no permanent storage.  It can't store off a
> cluster stack it is supposed to be using.  So it can't specify the stack
> name in ocfs2_cluster_connect().
>
> Instead, we create ocfs2_cluster_connect_agnostic(), which simply uses
> the stack that is currently enabled.  This is find for dlmfs, which will
> rely on the stack initialization.
>
> We add the "stackglue" capability to dlmfs's capability list.  This lets
> userspace know dlmfs can be used with all cluster stacks.
>
> Signed-off-by: Joel Becker <joel.becker@oracle.com>
> ---
>  fs/ocfs2/dlmfs/dlmfs.c      |    2 +-
>  fs/ocfs2/dlmfs/userdlm.c    |    8 ++++----
>  fs/ocfs2/ocfs2_lockingver.h |    2 ++
>  fs/ocfs2/stackglue.c        |   18 ++++++++++++++++++
>  fs/ocfs2/stackglue.h        |   11 +++++++++++
>  5 files changed, 36 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c
> index 8697366..1b0de15 100644
> --- a/fs/ocfs2/dlmfs/dlmfs.c
> +++ b/fs/ocfs2/dlmfs/dlmfs.c
> @@ -87,7 +87,7 @@ struct workqueue_struct *user_dlm_worker;
>   * - bast	: POLLIN against the file descriptor of a held lock
>   *		  signifies a bast fired on the lock.
>   */
> -#define DLMFS_CAPABILITIES "bast"
> +#define DLMFS_CAPABILITIES "bast stackglue"
>  extern int param_set_dlmfs_capabilities(const char *val,
>  					struct kernel_param *kp)
>  {
> diff --git a/fs/ocfs2/dlmfs/userdlm.c b/fs/ocfs2/dlmfs/userdlm.c
> index c1b6a56..2858ee6 100644
> --- a/fs/ocfs2/dlmfs/userdlm.c
> +++ b/fs/ocfs2/dlmfs/userdlm.c
> @@ -666,10 +666,10 @@ struct ocfs2_cluster_connection *user_dlm_register(struct qstr *name)
>  	int rc;
>  	struct ocfs2_cluster_connection *conn;
>  
> -	rc = ocfs2_cluster_connect("o2cb", name->name, name->len,
> -				   &user_dlm_lproto,
> -				   user_dlm_recovery_handler_noop,
> -				   NULL, &conn);
> +	rc = ocfs2_cluster_connect_agnostic(name->name, name->len,
> +					    &user_dlm_lproto,
> +					    user_dlm_recovery_handler_noop,
> +					    NULL, &conn);
>  	if (rc)
>  		mlog_errno(rc);
>  
> diff --git a/fs/ocfs2/ocfs2_lockingver.h b/fs/ocfs2/ocfs2_lockingver.h
> index 82d5eea..2e45c8d 100644
> --- a/fs/ocfs2/ocfs2_lockingver.h
> +++ b/fs/ocfs2/ocfs2_lockingver.h
> @@ -23,6 +23,8 @@
>  /*
>   * The protocol version for ocfs2 cluster locking.  See dlmglue.c for
>   * more details.
> + *
> + * 1.0 - Initial locking version from ocfs2 1.4.
>   */
>  #define OCFS2_LOCKING_PROTOCOL_MAJOR 1
>  #define OCFS2_LOCKING_PROTOCOL_MINOR 0
> diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
> index 31db2e8..39abf89 100644
> --- a/fs/ocfs2/stackglue.c
> +++ b/fs/ocfs2/stackglue.c
> @@ -373,6 +373,24 @@ out:
>  }
>  EXPORT_SYMBOL_GPL(ocfs2_cluster_connect);
>  
> +/* The caller will ensure all nodes have the same cluster stack */
> +int ocfs2_cluster_connect_agnostic(const char *group,
> +				   int grouplen,
> +				   struct ocfs2_locking_protocol *lproto,
> +				   void (*recovery_handler)(int node_num,
> +							    void *recovery_data),
> +				   void *recovery_data,
> +				   struct ocfs2_cluster_connection **conn)
> +{
> +	char *stack_name = NULL;
> +
> +	if (cluster_stack_name[0])
> +		stack_name = cluster_stack_name;
> +	return ocfs2_cluster_connect(stack_name, group, grouplen, lproto,
> +				     recovery_handler, recovery_data, conn);
> +}
> +EXPORT_SYMBOL_GPL(ocfs2_cluster_connect_agnostic);
> +
>  /* If hangup_pending is 0, the stack driver will be dropped */
>  int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
>  			     int hangup_pending)
> diff --git a/fs/ocfs2/stackglue.h b/fs/ocfs2/stackglue.h
> index b1981ba..8ce7398 100644
> --- a/fs/ocfs2/stackglue.h
> +++ b/fs/ocfs2/stackglue.h
> @@ -246,6 +246,17 @@ int ocfs2_cluster_connect(const char *stack_name,
>  						   void *recovery_data),
>  			  void *recovery_data,
>  			  struct ocfs2_cluster_connection **conn);
> +/*
> + * Used by callers that don't store their stack name.  They must ensure
> + * all nodes have the same stack.
> + */
> +int ocfs2_cluster_connect_agnostic(const char *group,
> +				   int grouplen,
> +				   struct ocfs2_locking_protocol *lproto,
> +				   void (*recovery_handler)(int node_num,
> +							    void *recovery_data),
> +				   void *recovery_data,
> +				   struct ocfs2_cluster_connection **conn);
>  int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
>  			     int hangup_pending);
>  void ocfs2_cluster_hangup(const char *group, int grouplen);
>