linux-kernel - Re: [Patch] btrfs: use file_remove_suid() after i

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Message-ID: <20090705224823.5679075f@infradead.org>
Date:	Sun, 5 Jul 2009 22:48:23 -0700
From:	Arjan van de Ven <arjan@...radead.org>
To:	Amerigo Wang <amwang@...hat.com>
Cc:	linux-kernel@...r.kernel.org, Jeff Mahoney <jeffm@...e.com>,
	Yan Zheng <zheng.yan@...cle.com>,
	Josef Bacik <jbacik@...hat.com>,
	Chris Mason <chris.mason@...cle.com>,
	Amerigo Wang <amwang@...hat.com>, akpm@...ux-foundation.org,
	linux-btrfs@...r.kernel.org,
	Sven Wegener <sven.wegener@...aler.net>
Subject: Re: [Patch] btrfs: use file_remove_suid() after i_mutex is held

On Mon, 6 Jul 2009 01:29:14 -0400
Amerigo Wang <amwang@...hat.com> wrote:

> 
> file_remove_suid() should be called with i_mutex held,
> file_update_time() too. So move them after mutex_lock().
> 
> Plus, check the return value of kmalloc().
> 
> Signed-off-by: WANG Cong <amwang@...hat.com>
> 
> ---
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index 7c3cd24..cd36301 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -944,14 +944,17 @@ static ssize_t btrfs_file_write(struct file
> *file, const char __user *buf, if (count == 0)
>  		goto out_nolock;
>  
> +	mutex_lock(&inode->i_mutex);
> +
>  	err = file_remove_suid(file);
>  	if (err)
> -		goto out_nolock;
> +		goto out;
>  	file_update_time(file);
>  
>  	pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
> +	if (!pages)
> +		goto out;
>  
Hi,

I don't think you can keep this at GFP_KERNEL once you hold i_mutex....
very likely this needs to now turn into GFP_NOFS!



-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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