[Ocfs2-devel] [PATCH] ocfs2: free meta_ac and data_ac when ocfs2_start_trans fails in ocfs2_xattr_set()

[Younger Liu <younger.liu@huawei.com>]

On 2013/8/7 6:44, Jeff Liu wrote:
> On 08/01/2013 05:02 PM, Younger Liu wrote:
> 
>> In ocfs2_xattr_set(), if ocfs2_start_trans failed, 
>> meta_ac and data_ac should be free. 
>> Otherwise, It would lead to  memory leak.
>>
>> Signed-off-by: Younger Liu <younger.liu@huawei.com>
>> Cc: Joseph Qi <joseph.qi@huawei.com>
>> ---
>>  fs/ocfs2/xattr.c |    5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
>> index 317ef0a..1c2a892 100644
>> --- a/fs/ocfs2/xattr.c
>> +++ b/fs/ocfs2/xattr.c
>> @@ -3505,7 +3505,7 @@ int ocfs2_xattr_set(struct inode *inode,
>>  	int ret, credits, ref_meta = 0, ref_credits = 0;
>>  	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
>>  	struct inode *tl_inode = osb->osb_tl_inode;
>> -	struct ocfs2_xattr_set_ctxt ctxt = { NULL, NULL, };
>> +	struct ocfs2_xattr_set_ctxt ctxt = { NULL, NULL, NULL, };
>>  	struct ocfs2_refcount_tree *ref_tree = NULL;
>>  
>>  	struct ocfs2_xattr_info xi = {
>> @@ -3609,13 +3609,14 @@ int ocfs2_xattr_set(struct inode *inode,
>>  	if (IS_ERR(ctxt.handle)) {
>>  		ret = PTR_ERR(ctxt.handle);
>>  		mlog_errno(ret);
>> -		goto cleanup;
>> +		goto out_free_ac;
>>  	}
>>  
>>  	ret = __ocfs2_xattr_set_handle(inode, di, &xi, &xis, &xbs, &ctxt);
>>  
>>  	ocfs2_commit_trans(osb, ctxt.handle);
>>  
>> +out_free_ac:
>>  	if (ctxt.data_ac)
>>  		ocfs2_free_alloc_context(ctxt.data_ac);
>>  	if (ctxt.meta_ac)
> 
> Yes, we should free the allocated contex in this case.
> However, we don't performs the log truncation as well as the delayed allocation
> business as per the old logic.
> 
> Srinivas,
> 
> How do you think about this fix?
> 
> Thanks,
> -Jeff
> 
In ocfs2_init_xattr_set_ctxt(), the allocated contex is initialized, 
(&ctxt.dealloc)->c_global_allocator and (&ctxt.dealloc)->
c_first_suballocator are set to NULL.

After applying the patch, if ocfs2_start_trans fails, we would free 
meta_ac/data_ac, but not perform truncate_log_flush/ocfs2_run_deallocs.
So, it would take no side effect to the function.

Thanks.
	--Younger