linux-kernel - Re: [PATCH 06/18] exofs: use iput() for inode reference count decrements

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Message-ID: <4CB5C70A.2010401@panasas.com>
Date:	Wed, 13 Oct 2010 10:49:46 -0400
From:	Boaz Harrosh <bharrosh@...asas.com>
To:	Christoph Hellwig <hch@...radead.org>
CC:	Dave Chinner <david@...morbit.com>, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 06/18] exofs: use iput() for inode reference count decrements

On 10/13/2010 07:34 AM, Christoph Hellwig wrote:
> Btw, this looks like a nasty enough bug that it might be worth queing
> up for 2.6.36.
> 
> On Wed, Oct 13, 2010 at 11:15:49AM +1100, Dave Chinner wrote:
>> From: Dave Chinner <dchinner@...hat.com>
>>
>> Direct modification of the inode reference count is a no-no. Convert
>> the exofs decrements to call iput() instead of acting directly on
>> i_count.
>>
>> Signed-off-by: Dave Chinner <dchinner@...hat.com>
>> Reviewed-by: Christoph Hellwig <hch@....de>
>> ---
>>  fs/exofs/inode.c |    4 ++--
>>  1 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
>> index b631ff3..0fb4d4c 100644
>> --- a/fs/exofs/inode.c
>> +++ b/fs/exofs/inode.c
>> @@ -1101,7 +1101,7 @@ static void create_done(struct exofs_io_state *ios, void *p)
>>  
>>  	set_obj_created(oi);
>>  
>> -	atomic_dec(&inode->i_count);
>> +	iput(inode);
>>  	wake_up(&oi->i_wq);
>>  }
>>  
>> @@ -1161,7 +1161,7 @@ struct inode *exofs_new_inode(struct inode *dir, int mode)
>>  	ios->cred = oi->i_cred;
>>  	ret = exofs_sbi_create(ios);
>>  	if (ret) {
>> -		atomic_dec(&inode->i_count);
>> +		iput(inode);
>>  		exofs_put_io_state(ios);
>>  		return ERR_PTR(ret);
>>  	}
>> -- 

I suspect it's not a bug but a useless inc/dec because in all my testing
I have not seen an inode leak. Let me investigate if it can be removed.

So I do not think we need it for 2.6.36.

I'll take this patch into my 2.6.37-rcX merge window. It should appear
in linux-next by tomorrow. Hopefully followed by a removal patch later.

Thanks for the catch
Boaz
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