Re: [PATCH] ocfs2: embed actual values into ocfs2_sysfile_lock_key names

[Heming Zhao <heming.zhao@suse.com>]

I am not familiar with lockdep, and just have two questions regarding
the lockdep in ocfs2.

1>
there are three global "static struct lock_class_key" definitions:
- fs/ocfs2/inode.c  : ocfs2_sysfile_lock_key[NUM_SYSTEM_INODES]
- fs/ocfs2/dlmglue.c: lockdep_keys[OCFS2_NUM_LOCK_TYPES]
- fs/ocfs2/sysfile.c: ocfs2_sysfile_cluster_lock_key[NUM_SYSTEM_INODES]

why did you env only trigger the ocfs2_sysfile_lock_key[] warning?

2>
It seems the existing CONFIG_DEBUG_LOCK_ALLOC is incorrect, it should be
replaced with CONFIG_LOCKDEP.

- Heming

On 6/30/25 10:21, Joseph Qi wrote:
> 
> 
> On 2025/6/23 22:54, Tetsuo Handa wrote:
>> Since lockdep_set_class() uses stringified key name via macro, calling
>> lockdep_set_class() with an array causes lockdep warning messages to
>> report variable name than actual index number.
>>
>> Change ocfs2_init_locked_inode() to pass actual index number for better
>> readability of lockdep reports. This patch does not change behavior.
>>
>>
>> Before:
>>
>>    Chain exists of:
>>      &ocfs2_sysfile_lock_key[args->fi_sysfile_type] --> jbd2_handle --> &oi->ip_xattr_sem
>>
>>     Possible unsafe locking scenario:
>>
>>           CPU0                    CPU1
>>           ----                    ----
>>      lock(&oi->ip_xattr_sem);
>>                                   lock(jbd2_handle);
>>                                   lock(&oi->ip_xattr_sem);
>>      lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]);
>>
>>     *** DEADLOCK ***
>>
>> After:
>>
>>    Chain exists of:
>>      &ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE] --> jbd2_handle --> &oi->ip_xattr_sem
>>
>>     Possible unsafe locking scenario:
>>
>>           CPU0                    CPU1
>>           ----                    ----
>>      lock(&oi->ip_xattr_sem);
>>                                   lock(jbd2_handle);
>>                                   lock(&oi->ip_xattr_sem);
>>      lock(&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]);
>>
>>     *** DEADLOCK ***
>>
>>
>> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> 
> Looks fine.
> 
> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
>> ---
>>   fs/ocfs2/inode.c | 70 +++++++++++++++++++++++++++++++++++++++++++++---
>>   1 file changed, 66 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
>> index 12e5d1f73325..14bf440ea4df 100644
>> --- a/fs/ocfs2/inode.c
>> +++ b/fs/ocfs2/inode.c
>> @@ -50,8 +50,6 @@ struct ocfs2_find_inode_args
>>   	unsigned int	fi_sysfile_type;
>>   };
>>   
>> -static struct lock_class_key ocfs2_sysfile_lock_key[NUM_SYSTEM_INODES];
>> -
>>   static int ocfs2_read_locked_inode(struct inode *inode,
>>   				   struct ocfs2_find_inode_args *args);
>>   static int ocfs2_init_locked_inode(struct inode *inode, void *opaque);
>> @@ -250,14 +248,77 @@ static int ocfs2_find_actor(struct inode *inode, void *opaque)
>>   static int ocfs2_init_locked_inode(struct inode *inode, void *opaque)
>>   {
>>   	struct ocfs2_find_inode_args *args = opaque;
>> +#ifdef CONFIG_LOCKDEP
>> +	static struct lock_class_key ocfs2_sysfile_lock_key[NUM_SYSTEM_INODES];
>>   	static struct lock_class_key ocfs2_quota_ip_alloc_sem_key,
>>   				     ocfs2_file_ip_alloc_sem_key;
>> +#endif
>>   
>>   	inode->i_ino = args->fi_ino;
>>   	OCFS2_I(inode)->ip_blkno = args->fi_blkno;
>> -	if (args->fi_sysfile_type != 0)
>> +#ifdef CONFIG_LOCKDEP
>> +	switch (args->fi_sysfile_type) {
>> +	case BAD_BLOCK_SYSTEM_INODE:
>> +		break;
>> +	case GLOBAL_INODE_ALLOC_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[GLOBAL_INODE_ALLOC_SYSTEM_INODE]);
>> +		break;
>> +	case SLOT_MAP_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[SLOT_MAP_SYSTEM_INODE]);
>> +		break;
>> +	case HEARTBEAT_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[HEARTBEAT_SYSTEM_INODE]);
>> +		break;
>> +	case GLOBAL_BITMAP_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[GLOBAL_BITMAP_SYSTEM_INODE]);
>> +		break;
>> +	case USER_QUOTA_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[USER_QUOTA_SYSTEM_INODE]);
>> +		break;
>> +	case GROUP_QUOTA_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[GROUP_QUOTA_SYSTEM_INODE]);
>> +		break;
>> +	case ORPHAN_DIR_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]);
>> +		break;
>> +	case EXTENT_ALLOC_SYSTEM_INODE:
>>   		lockdep_set_class(&inode->i_rwsem,
>> -			&ocfs2_sysfile_lock_key[args->fi_sysfile_type]);
>> +				  &ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]);
>> +		break;
>> +	case INODE_ALLOC_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]);
>> +		break;
>> +	case JOURNAL_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[JOURNAL_SYSTEM_INODE]);
>> +		break;
>> +	case LOCAL_ALLOC_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[LOCAL_ALLOC_SYSTEM_INODE]);
>> +		break;
>> +	case TRUNCATE_LOG_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[TRUNCATE_LOG_SYSTEM_INODE]);
>> +		break;
>> +	case LOCAL_USER_QUOTA_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[LOCAL_USER_QUOTA_SYSTEM_INODE]);
>> +		break;
>> +	case LOCAL_GROUP_QUOTA_SYSTEM_INODE:
>> +		lockdep_set_class(&inode->i_rwsem,
>> +				  &ocfs2_sysfile_lock_key[LOCAL_GROUP_QUOTA_SYSTEM_INODE]);
>> +		break;
>> +	default:
>> +		WARN_ONCE(1, "Unknown sysfile type %d\n", args->fi_sysfile_type);
>> +	}
>>   	if (args->fi_sysfile_type == USER_QUOTA_SYSTEM_INODE ||
>>   	    args->fi_sysfile_type == GROUP_QUOTA_SYSTEM_INODE ||
>>   	    args->fi_sysfile_type == LOCAL_USER_QUOTA_SYSTEM_INODE ||
>> @@ -267,6 +328,7 @@ static int ocfs2_init_locked_inode(struct inode *inode, void *opaque)
>>   	else
>>   		lockdep_set_class(&OCFS2_I(inode)->ip_alloc_sem,
>>   				  &ocfs2_file_ip_alloc_sem_key);
>> +#endif
>>   
>>   	return 0;
>>   }
> 
>