[PATCH] zonefs: Fix race between modprobe and mount

[PATCH] zonefs: Fix race between modprobe and mount

[Zhang Xiaoxu]

There is a race between modprobe and mount as below:

 modprobe zonefs                | mount -t zonefs
--------------------------------|-------------------------
 zonefs_init                    |
  register_filesystem       [1] |
                                | zonefs_fill_super    [2]
  zonefs_sysfs_init         [3] |

1. register zonefs suceess, then
2. user can mount the zonefs
3. if sysfs initialize failed, the module initialize failed.

Then the mount process maybe some error happened since the module
initialize failed.

Let's register zonefs after all dependency resource ready. And
reorder the dependency resource release in module exit.

Fixes: 9277a6d4fbd4 ("zonefs: Export open zone resource information through sysfs")
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
---
 fs/zonefs/super.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index 860f0b1032c6..625749fbedf4 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -1905,18 +1905,18 @@ static int __init zonefs_init(void)
 	if (ret)
 		return ret;
 
-	ret = register_filesystem(&zonefs_type);
+	ret = zonefs_sysfs_init();
 	if (ret)
 		goto destroy_inodecache;
 
-	ret = zonefs_sysfs_init();
+	ret = register_filesystem(&zonefs_type);
 	if (ret)
-		goto unregister_fs;
+		goto sysfs_exit;
 
 	return 0;
 
-unregister_fs:
-	unregister_filesystem(&zonefs_type);
+sysfs_exit:
+	zonefs_sysfs_exit();
 destroy_inodecache:
 	zonefs_destroy_inodecache();
 
@@ -1925,9 +1925,9 @@ static int __init zonefs_init(void)
 
 static void __exit zonefs_exit(void)
 {
+	unregister_filesystem(&zonefs_type);
 	zonefs_sysfs_exit();
 	zonefs_destroy_inodecache();
-	unregister_filesystem(&zonefs_type);
 }
 
 MODULE_AUTHOR("Damien Le Moal");
-- 
2.31.1

Re: [PATCH] zonefs: Fix race between modprobe and mount

[Johannes Thumshirn]

Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Re: [PATCH] zonefs: Fix race between modprobe and mount

[Chaitanya Kulkarni]

On 11/20/22 02:57, Zhang Xiaoxu wrote:
> There is a race between modprobe and mount as below:
> 
>   modprobe zonefs                | mount -t zonefs
> --------------------------------|-------------------------
>   zonefs_init                    |
>    register_filesystem       [1] |
>                                  | zonefs_fill_super    [2]
>    zonefs_sysfs_init         [3] |
> 
> 1. register zonefs suceess, then
> 2. user can mount the zonefs
> 3. if sysfs initialize failed, the module initialize failed.
> 
> Then the mount process maybe some error happened since the module
> initialize failed.
> 
> Let's register zonefs after all dependency resource ready. And
> reorder the dependency resource release in module exit.
> 
> Fixes: 9277a6d4fbd4 ("zonefs: Export open zone resource information through sysfs")
> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
> ---

Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>

-ck

Re: [PATCH] zonefs: Fix race between modprobe and mount

[Damien Le Moal]

On 11/20/22 19:57, Zhang Xiaoxu wrote:
> There is a race between modprobe and mount as below:
> 
>  modprobe zonefs                | mount -t zonefs
> --------------------------------|-------------------------
>  zonefs_init                    |
>   register_filesystem       [1] |
>                                 | zonefs_fill_super    [2]
>   zonefs_sysfs_init         [3] |
> 
> 1. register zonefs suceess, then
> 2. user can mount the zonefs
> 3. if sysfs initialize failed, the module initialize failed.
> 
> Then the mount process maybe some error happened since the module
> initialize failed.
> 
> Let's register zonefs after all dependency resource ready. And
> reorder the dependency resource release in module exit.
> 
> Fixes: 9277a6d4fbd4 ("zonefs: Export open zone resource information through sysfs")
> Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>

Applied to for-6.1-fixes. Thanks !

> ---
>  fs/zonefs/super.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
> index 860f0b1032c6..625749fbedf4 100644
> --- a/fs/zonefs/super.c
> +++ b/fs/zonefs/super.c
> @@ -1905,18 +1905,18 @@ static int __init zonefs_init(void)
>  	if (ret)
>  		return ret;
>  
> -	ret = register_filesystem(&zonefs_type);
> +	ret = zonefs_sysfs_init();
>  	if (ret)
>  		goto destroy_inodecache;
>  
> -	ret = zonefs_sysfs_init();
> +	ret = register_filesystem(&zonefs_type);
>  	if (ret)
> -		goto unregister_fs;
> +		goto sysfs_exit;
>  
>  	return 0;
>  
> -unregister_fs:
> -	unregister_filesystem(&zonefs_type);
> +sysfs_exit:
> +	zonefs_sysfs_exit();
>  destroy_inodecache:
>  	zonefs_destroy_inodecache();
>  
> @@ -1925,9 +1925,9 @@ static int __init zonefs_init(void)
>  
>  static void __exit zonefs_exit(void)
>  {
> +	unregister_filesystem(&zonefs_type);
>  	zonefs_sysfs_exit();
>  	zonefs_destroy_inodecache();
> -	unregister_filesystem(&zonefs_type);
>  }
>  
>  MODULE_AUTHOR("Damien Le Moal");

-- 
Damien Le Moal
Western Digital Research