Re: [PATCH RFC v16 01/11] fs/lock: add helper locks_owner_has_blockers to check for blockers

[dai.ngo@oracle.com]

Hi Chuck,

On 3/16/22 7:27 AM, Chuck Lever III wrote:
>
>> On Mar 11, 2022, at 9:13 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>
>> Add helper locks_owner_has_blockers to check if there is any blockers
>> for a given lockowner.
>>
>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>> ---
>> fs/locks.c         | 28 ++++++++++++++++++++++++++++
>> include/linux/fs.h |  7 +++++++
>> 2 files changed, 35 insertions(+)
>>
>> diff --git a/fs/locks.c b/fs/locks.c
>> index 050acf8b5110..53864eb99dc5 100644
>> --- a/fs/locks.c
>> +++ b/fs/locks.c
>> @@ -300,6 +300,34 @@ void locks_release_private(struct file_lock *fl)
>> }
>> EXPORT_SYMBOL_GPL(locks_release_private);
>>
>> +/**
>> + * locks_owner_has_blockers - Check for blocking lock requests
>> + * @flctx: file lock context
>> + * @owner: lock owner
>> + *
>> + * Return values:
>> + *   %true: @owner has at least one blocker
>> + *   %false: @owner has no blockers
>> + */
>> +bool locks_owner_has_blockers(struct file_lock_context *flctx,
>> +		fl_owner_t owner)
>> +{
>> +	struct file_lock *fl;
>> +
>> +	spin_lock(&flctx->flc_lock);
>> +	list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
>> +		if (fl->fl_owner != owner)
>> +			continue;
>> +		if (!list_empty(&fl->fl_blocked_requests)) {
>> +			spin_unlock(&flctx->flc_lock);
>> +			return true;
>> +		}
>> +	}
>> +	spin_unlock(&flctx->flc_lock);
>> +	return false;
>> +}
>> +EXPORT_SYMBOL_GPL(locks_owner_has_blockers);
>> +
>> /* Free a lock which is not in use. */
>> void locks_free_lock(struct file_lock *fl)
>> {
>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>> index 831b20430d6e..da8ae38f471c 100644
>> --- a/include/linux/fs.h
>> +++ b/include/linux/fs.h
>> @@ -1200,6 +1200,8 @@ extern void lease_unregister_notifier(struct notifier_block *);
>> struct files_struct;
>> extern void show_fd_locks(struct seq_file *f,
>> 			 struct file *filp, struct files_struct *files);
>> +extern bool locks_owner_has_blockers(struct file_lock_context *flctx,
>> +			fl_owner_t owner);
>> #else /* !CONFIG_FILE_LOCKING */
>> static inline int fcntl_getlk(struct file *file, unsigned int cmd,
>> 			      struct flock __user *user)
>> @@ -1335,6 +1337,11 @@ static inline int lease_modify(struct file_lock *fl, int arg,
>> struct files_struct;
>> static inline void show_fd_locks(struct seq_file *f,
>> 			struct file *filp, struct files_struct *files) {}
>> +extern bool locks_owner_has_blockers(struct file_lock_context *flctx,
>> +			fl_owner_t owner)
> Here's the problem, Dai.
>
> This empty function needs to be declared "static inline" not "extern".

Yes, I also found it last night with the 2nd notice from
kernel test robot. Fix in v17.

-Dai

>
>
>> +{
>> +	return false;
>> +}
>> #endif /* !CONFIG_FILE_LOCKING */
>>
>> static inline struct inode *file_inode(const struct file *f)
>> -- 
>> 2.9.5
>>
> --
> Chuck Lever
>
>
>