[Ocfs2-devel] [patch 07/28] ocfs2: fix a tiny case that inode can not removed.

[jiangyiwen]

On 2015/8/29 7:26, Mark Fasheh wrote:
> On Wed, Aug 26, 2015 at 03:11:37PM -0700, Andrew Morton wrote:
>> From: jiangyiwen <jiangyiwen at huawei.com>
>> Subject: ocfs2: fix a tiny case that inode can not removed.
>>
>> When running dirop_fileop_racer we found a case that inode
>> can not removed.
>>
>> 2 nodes, say Node A and Node B, mount the same ocfs2 volume. Create
>> two dirs /race/1/ and /race/2/ in the filesystem.
>>
>> Node A                            Node B
>> rm -r /race/2/
>>                                   mv /race/1/ /race/2/
>> call ocfs2_unlink(), get
>> the EX mode of /race/2/
>>                                   wait for B unlock /race/2/
>> decrease i_nlink of /race/2/ to 0,
>> and add inode of /race/2/ into
>> orphan dir, unlock /race/2/
>>                                   got EX mode of /race/2/. because
>>                                   /race/1/ is dir, so inc i_nlink
>>                                   of /race/2/ and update into disk,
>>                                   unlock /race/2/
>> because i_nlink of /race/2/
>> is not zero, this inode will
>> always remain in orphan dir
>>
>> This patch fixes this case by test whether i_nlink of new dir is zero.
> 
> 
> Good catch, thanks for this.
> 
> 
>> diff -puN fs/ocfs2/namei.c~ocfs2-fix-a-tiny-case-that-inode-can-not-removed fs/ocfs2/namei.c
>> --- a/fs/ocfs2/namei.c~ocfs2-fix-a-tiny-case-that-inode-can-not-removed
>> +++ a/fs/ocfs2/namei.c
>> @@ -1284,6 +1284,15 @@ static int ocfs2_rename(struct inode *ol
>>  	}
>>  	parents_locked = 1;
>>  
>> +	if (!new_dir->i_nlink) {
>> +		mlog(ML_ERROR, "new dir %llu has been removed, inode %llu "
>> +				"can not be moved into it.",
>> +				(unsigned long long)new_dir->i_ino,
>> +				(unsigned long long)old_inode->i_ino);
> 
> This is something that is rare, but not an error or otherwise outstanding
> condition. Therefore printing to the kernel log is not advisable and may
> confuse users. Please turn that into a debug print or remove it all
> together, thanks.
> 	--Mark
> 
> --
> Mark Fasheh
> 
> .
> 
OK, thanks Mark, I will resend a new version immediately.

Thanks,
Yiwen Jiang