[PATCH] ocfs2: fix module_init error handling

[PATCH] ocfs2: fix module_init error handling

[Akinobu Mita]

From: Akinobu Mita <akinobu.mita@gmail.com>
Subject: [PATCH] ocfs2: fix module_init error handling

Fix error handling in module_init and make module_init() return
correct error code.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: Kurt Hackel <kurt.hackel@oracle.com>
---
 fs/ocfs2/super.c |   42 +++++++++++++++++++++++++++---------------
 1 file changed, 27 insertions(+), 15 deletions(-)

Index: 2.6-mm/fs/ocfs2/super.c
===================================================================
--- 2.6-mm.orig/fs/ocfs2/super.c
+++ 2.6-mm/fs/ocfs2/super.c
@@ -806,46 +806,58 @@ static int __init ocfs2_init(void)
 
 	ocfs2_print_version();
 
-	if (init_ocfs2_extent_maps())
-		return -ENOMEM;
+	status = init_ocfs2_extent_maps();
+	if (status)
+		goto err_extent_maps;
 
 	status = init_ocfs2_uptodate_cache();
 	if (status < 0) {
 		mlog_errno(status);
-		goto leave;
+		goto err_uptodate_cache;
 	}
 
 	status = ocfs2_initialize_mem_caches();
 	if (status < 0) {
 		mlog_errno(status);
-		goto leave;
+		goto err_mem_caches;
 	}
 
 	ocfs2_wq = create_singlethread_workqueue("ocfs2_wq");
 	if (!ocfs2_wq) {
 		status = -ENOMEM;
-		goto leave;
+		goto err_workqueue;
 	}
 
 	ocfs2_debugfs_root = debugfs_create_dir("ocfs2", NULL);
 	if (!ocfs2_debugfs_root) {
 		status = -EFAULT;
 		mlog(ML_ERROR, "Unable to create ocfs2 debugfs root.\n");
+		goto err_debugfs;
 	}
 
-leave:
-	if (status < 0) {
-		ocfs2_free_mem_caches();
-		exit_ocfs2_uptodate_cache();
-		exit_ocfs2_extent_maps();
-	}
+	status = register_filesystem(&ocfs2_fs_type);
+	if (status)
+		goto err_filesystem;
 
 	mlog_exit(status);
 
-	if (status >= 0) {
-		return register_filesystem(&ocfs2_fs_type);
-	} else
-		return -1;
+	return 0;
+
+err_filesystem:
+	debugfs_remove(ocfs2_debugfs_root);
+err_debugfs:
+	flush_workqueue(ocfs2_wq);
+	destroy_workqueue(ocfs2_wq);
+err_workqueue:
+	ocfs2_free_mem_caches();
+err_mem_caches:
+	exit_ocfs2_uptodate_cache();
+err_uptodate_cache:
+	exit_ocfs2_extent_maps();
+err_extent_maps:
+	mlog_exit(status);
+
+	return status;
 }
 
 static void __exit ocfs2_exit(void)

Re: [PATCH] ocfs2: fix module_init error handling

[Joel Becker]

On Sun, Mar 04, 2007 at 10:34:43PM +0900, Akinobu Mita wrote:
> From: Akinobu Mita <akinobu.mita@gmail.com>
> Subject: [PATCH] ocfs2: fix module_init error handling
> 
> Fix error handling in module_init and make module_init() return
> correct error code.

	What are you fixing specifically?  This looks like you are
reorganizing the exit path.  While stylistic differences can exist on
the choice of function exit, claiming there is a "fix" means there is an
actual bug.  Please clarify the bug so we can evaluate your change.

> -leave:
> -	if (status < 0) {
> -		ocfs2_free_mem_caches();
> -		exit_ocfs2_uptodate_cache();
> -		exit_ocfs2_extent_maps();
> -	}
> +	status = register_filesystem(&ocfs2_fs_type);
> +	if (status)
> +		goto err_filesystem;
>  
>  	mlog_exit(status);

	Also, this change suppresses some paths to mlog_exit(), which
impacts people tracing.
	If there is an actual bug you are fixing, please tell us.  We'll
work with you to correct it.

Joel

-- 

Life's Little Instruction Book #451

	"Don't be afraid to say, 'I'm sorry.'"

Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127

Re: [PATCH] ocfs2: fix module_init error handling

[Akinobu Mita]

2007/3/6, Joel Becker <Joel.Becker@oracle.com>:
> On Sun, Mar 04, 2007 at 10:34:43PM +0900, Akinobu Mita wrote:
> > From: Akinobu Mita <akinobu.mita@gmail.com>
> > Subject: [PATCH] ocfs2: fix module_init error handling
> >
> > Fix error handling in module_init and make module_init() return
> > correct error code.
>
>         What are you fixing specifically?  This looks like you are
> reorganizing the exit path.  While stylistic differences can exist on
> the choice of function exit, claiming there is a "fix" means there is an
> actual bug.  Please clarify the bug so we can evaluate your change.

OK. There are three problems (these are not likely to happen)

- There is no error handling when register_filesystem() fails
  (several slab caches, debugfs directory, and workqueue will not be cleaned)

- workqueue will not be cleaned if debugfs_create_dir() returns error.

- kmem_cache_destroy() with NULL oops will happen if
  ocfs2_free_mem_caches(), exit_ocfs2_uptodate_cache(),
  or exit_ocfs2_extent_maps() return error.

Re: [PATCH] ocfs2: fix module_init error handling

[Mark Fasheh]

On Wed, Mar 07, 2007 at 01:38:17AM +0900, Akinobu Mita wrote:
> OK. There are three problems (these are not likely to happen)
> 
> - There is no error handling when register_filesystem() fails
>  (several slab caches, debugfs directory, and workqueue will not be cleaned)
> 
> - workqueue will not be cleaned if debugfs_create_dir() returns error.
> 
> - kmem_cache_destroy() with NULL oops will happen if
>  ocfs2_free_mem_caches(), exit_ocfs2_uptodate_cache(),
>  or exit_ocfs2_extent_maps() return error.

Ok, both those patches are in ocfs2.git now.
	--Mark

--
Mark Fasheh
Senior Software Developer, Oracle
mark.fasheh@oracle.com