[PATCH V3] md-cluster: make md-cluster also can work when compiled into kernel

[PATCH V3] md-cluster: make md-cluster also can work when compiled into kernel

[Guoqing Jiang]

The md-cluster is compiled as module by default,
if it is compiled by built-in way, then we can't
make md-cluster works.

[64782.630008] md/raid1:md127: active with 2 out of 2 mirrors
[64782.630528] md-cluster module not found.
[64782.630530] md127: Could not setup cluster service (-2)

Fixes: edb39c9 ("Introduce md_cluster_operations to handle cluster functions")
Cc: stable@vger.kernel.org (v4.1+)
Cc: NeilBrown <neilb@suse.com>
Reported-by: Marc Smith <marc.smith@mcc.edu>
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
---
V3 changes:
1. add the "!md_cluster_ops" test back
2. fix wrong mail info of stable kernel

V2 changes:
1. call try_module_get if md_cluster_ops is already set,
   otherwise try_module_get/module_put are unbalanced.

 drivers/md/md.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 67642ba..915e84d 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -7610,16 +7610,12 @@ EXPORT_SYMBOL(unregister_md_cluster_operations);
 
 int md_setup_cluster(struct mddev *mddev, int nodes)
 {
-	int err;
-
-	err = request_module("md-cluster");
-	if (err) {
-		pr_err("md-cluster module not found.\n");
-		return -ENOENT;
-	}
-
+	if (!md_cluster_ops)
+		request_module("md-cluster");
 	spin_lock(&pers_lock);
+	/* ensure module won't be unloaded */
 	if (!md_cluster_ops || !try_module_get(md_cluster_mod)) {
+		pr_err("can't find md-cluster module or get it's reference.\n");
 		spin_unlock(&pers_lock);
 		return -ENOENT;
 	}
-- 
2.6.6

Re: [PATCH V3] md-cluster: make md-cluster also can work when compiled into kernel

[NeilBrown]

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On Mon, Sep 05 2016, Guoqing Jiang wrote:

> The md-cluster is compiled as module by default,
> if it is compiled by built-in way, then we can't
> make md-cluster works.
>
> [64782.630008] md/raid1:md127: active with 2 out of 2 mirrors
> [64782.630528] md-cluster module not found.
> [64782.630530] md127: Could not setup cluster service (-2)
>
> Fixes: edb39c9 ("Introduce md_cluster_operations to handle cluster functions")
> Cc: stable@vger.kernel.org (v4.1+)
> Cc: NeilBrown <neilb@suse.com>
> Reported-by: Marc Smith <marc.smith@mcc.edu>
> Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
> ---
> V3 changes:
> 1. add the "!md_cluster_ops" test back
> 2. fix wrong mail info of stable kernel
>
> V2 changes:
> 1. call try_module_get if md_cluster_ops is already set,
>    otherwise try_module_get/module_put are unbalanced.
>
>  drivers/md/md.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 67642ba..915e84d 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -7610,16 +7610,12 @@ EXPORT_SYMBOL(unregister_md_cluster_operations);
>  
>  int md_setup_cluster(struct mddev *mddev, int nodes)
>  {
> -	int err;
> -
> -	err = request_module("md-cluster");
> -	if (err) {
> -		pr_err("md-cluster module not found.\n");
> -		return -ENOENT;
> -	}
> -
> +	if (!md_cluster_ops)
> +		request_module("md-cluster");
>  	spin_lock(&pers_lock);
> +	/* ensure module won't be unloaded */
>  	if (!md_cluster_ops || !try_module_get(md_cluster_mod)) {
> +		pr_err("can't find md-cluster module or get it's reference.\n");
>  		spin_unlock(&pers_lock);
>  		return -ENOENT;
>  	}
> -- 
> 2.6.6

Reviewed-by: NeilBrown <neilb@suse.com>

Thanks,
NeilBrown

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Re: [PATCH V3] md-cluster: make md-cluster also can work when compiled into kernel

[Shaohua Li]

On Sun, Sep 04, 2016 at 10:17:28PM -0400, Guoqing Jiang wrote:
> The md-cluster is compiled as module by default,
> if it is compiled by built-in way, then we can't
> make md-cluster works.
> 
> [64782.630008] md/raid1:md127: active with 2 out of 2 mirrors
> [64782.630528] md-cluster module not found.
> [64782.630530] md127: Could not setup cluster service (-2)
> 
> Fixes: edb39c9 ("Introduce md_cluster_operations to handle cluster functions")
> Cc: stable@vger.kernel.org (v4.1+)
> Cc: NeilBrown <neilb@suse.com>
> Reported-by: Marc Smith <marc.smith@mcc.edu>
> Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
> ---
> V3 changes:
> 1. add the "!md_cluster_ops" test back
> 2. fix wrong mail info of stable kernel
> 
> V2 changes:
> 1. call try_module_get if md_cluster_ops is already set,
>    otherwise try_module_get/module_put are unbalanced.

applied, thanks!