linux-ext4 - Re: [PATCH] ext4: page_cache pages not released in ext4_mb_load

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Message-ID: <87eij9d5qs.fsf@linux.vnet.ibm.com>
Date:	Wed, 24 Mar 2010 22:19:47 +0530
From:	"Aneesh Kumar K. V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	jing zhang <zj.barak@...il.com>,
	linux-ext4 <linux-ext4@...r.kernel.org>
Cc:	"Theodore Ts'o" <tytso@....edu>, Andreas Dilger <adilger@....com>,
	Dave Kleikamp <shaggy@...ux.vnet.ibm.com>
Subject: Re: [PATCH] ext4: page_cache pages not released in
 ext4_mb_load_buddy()

On Wed, 24 Mar 2010 22:21:01 +0800, jing zhang <zj.barak@...il.com> wrote:
> From: Jing Zhang <zj.barak@...il.com>
> 
> Date: Wed Mar 24 20:38:48     2010
> 
> If ext4_mb_init_cache() returns error, there is no page_cache_release() issued.
> 
> Cc: Theodore Ts'o <tytso@....edu>
> Cc: Andreas Dilger <adilger@....com>
> Cc: Dave Kleikamp <shaggy@...ux.vnet.ibm.com>
> Signed-off-by: Jing Zhang <zj.barak@...il.com>
> 
> ---
> 
> --- linux-2.6.32/fs/ext4/mballoc.c	2009-12-03 11:51:22.000000000 +0800
> +++ ext4_mm_leak/mballoc-9.c	2010-03-24 22:24:56.000000000 +0800
> @@ -1132,8 +1132,6 @@ repeat_load_buddy:
>  	e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
>  	mark_page_accessed(page);
> 
> -	BUG_ON(e4b->bd_bitmap_page == NULL);
> -	BUG_ON(e4b->bd_buddy_page == NULL);

Why remove these ? 

> 
>  	return 0;
> 
> @@ -1142,6 +1140,8 @@ err:
>  		page_cache_release(e4b->bd_bitmap_page);
>  	if (e4b->bd_buddy_page)
>  		page_cache_release(e4b->bd_buddy_page);
> +	if (page)
> +		page_cache_release(page);
>  	e4b->bd_buddy = NULL;
>  	e4b->bd_bitmap = NULL;

Can you add a comment which says on error page will point to the page
cache page which haven't been assigned to neither bd_bitmap_page or
bd_buddy_page

But good catch !!

-aneesh
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