[Ocfs2-devel] [PATCH 7/7] Don't allow cluster_stack changes if FS are mounted

[Joel Becker <jlbec@evilplan.org>]

I thought we already prevented this.  Why a new mechanism?

Joel

On Fri, Sep 27, 2013 at 12:10:11PM -0500, Goldwyn Rodrigues wrote:
> ---
>  fs/ocfs2/dlmglue.c   |  3 ++-
>  fs/ocfs2/stackglue.c | 18 ++++++++++++++++++
>  fs/ocfs2/stackglue.h |  3 +++
>  3 files changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index f2d48c8..65b4280 100644
> --- a/fs/ocfs2/dlmglue.c
> +++ b/fs/ocfs2/dlmglue.c
> @@ -3023,7 +3023,7 @@ local:
>  	ocfs2_orphan_scan_lock_res_init(&osb->osb_orphan_scan.os_lockres, osb);
>  
>  	osb->cconn = conn;
> -
> +	ocfs2_inc_mount_count();
>  	status = 0;
>  bail:
>  	if (status < 0) {
> @@ -3058,6 +3058,7 @@ void ocfs2_dlm_shutdown(struct ocfs2_super *osb,
>  
>  	ocfs2_cluster_disconnect(osb->cconn, hangup_pending);
>  	osb->cconn = NULL;
> +	ocfs2_dec_mount_count();
>  
>  	ocfs2_dlm_shutdown_debug(osb);
>  }
> diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
> index 4dd732b..e352a2e 100644
> --- a/fs/ocfs2/stackglue.c
> +++ b/fs/ocfs2/stackglue.c
> @@ -41,6 +41,7 @@ static DEFINE_SPINLOCK(ocfs2_stack_lock);
>  static LIST_HEAD(ocfs2_stack_list);
>  static char cluster_stack_name[OCFS2_STACK_LABEL_LEN + 1];
>  static char ocfs2_hb_ctl_path[OCFS2_MAX_HB_CTL_PATH] = "/sbin/ocfs2_hb_ctl";
> +static atomic_t mount_count = ATOMIC_INIT(0);
>  
>  /*
>   * The stack currently in use.  If not null, active_stack->sp_count > 0,
> @@ -417,6 +418,18 @@ int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
>  }
>  EXPORT_SYMBOL_GPL(ocfs2_cluster_disconnect);
>  
> +void ocfs2_inc_mount_count()
> +{
> +	atomic_inc(&mount_count);
> +}
> +EXPORT_SYMBOL_GPL(ocfs2_inc_mount_count);
> +
> +void ocfs2_dec_mount_count()
> +{
> +	atomic_dec(&mount_count);
> +}
> +EXPORT_SYMBOL_GPL(ocfs2_dec_mount_count);
> +
>  /*
>   * Leave the group for this filesystem.  This is executed by a userspace
>   * program (stored in ocfs2_hb_ctl_path).
> @@ -569,6 +582,11 @@ static ssize_t ocfs2_cluster_stack_store(struct kobject *kobj,
>  	size_t len = count;
>  	ssize_t ret;
>  
> +	if (atomic_read(&mount_count) > 0) {
> +		printk(KERN_NOTICE "ocfs2_stackglue: Cannot set cluster_stack when filesystems are mounted.\n");
> +		return -EINVAL;
> +	}
> +
>  	if (len == 0)
>  		return len;
>  
> diff --git a/fs/ocfs2/stackglue.h b/fs/ocfs2/stackglue.h
> index d3a54df..da4a913 100644
> --- a/fs/ocfs2/stackglue.h
> +++ b/fs/ocfs2/stackglue.h
> @@ -293,6 +293,9 @@ int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
>  
>  void ocfs2_stack_glue_set_max_proto_version(struct ocfs2_protocol_version *max_proto);
>  
> +void ocfs2_inc_mount_count(void);
> +void ocfs2_dec_mount_count(void);
> +
>  
>  /* Used by stack plugins */
>  int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin);
> -- 
> 1.8.1.4
> 
> 
> -- 
> Goldwyn
> 
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-- 

"To fall in love is to create a religion that has a fallible god."
        -Jorge Luis Borges

			http://www.jlbec.org/
			jlbec at evilplan.org