[Ocfs2-devel] [PATCH] ocfs2: kill EBUSY from dlmfs_evict_inode

[Junxiao Bi]

On 6/4/22 3:10 AM, heming.zhao at suse.com wrote:
> Hello Junxiao,
>
> On 6/4/22 06:31, Junxiao Bi via Ocfs2-devel wrote:
>> When unlink a dlmfs, first it will invoke dlmfs_unlink(), and then 
>> invoke
>> dlmfs_evict_inode(), user_dlm_destroy_lock() is invoked in both places,
>> the second one from dlmfs_evict_inode() will get EBUSY error because
>> USER_LOCK_IN_TEARDOWN is already set in lockres. This doesn't affect
>> any function, just the error log is anonying.
>>
>> Signed-off-by: Junxiao Bi <junxiao.bi at oracle.com>
>> ---
>>   fs/ocfs2/dlmfs/dlmfs.c | 14 +++++++++++---
>>   1 file changed, 11 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c
>> index e360543ad7e7..a120610dff7e 100644
>> --- a/fs/ocfs2/dlmfs/dlmfs.c
>> +++ b/fs/ocfs2/dlmfs/dlmfs.c
>> @@ -296,17 +296,25 @@ static void dlmfs_evict_inode(struct inode *inode)
>>   {
>>       int status;
>>       struct dlmfs_inode_private *ip;
>> +    struct user_lock_res *lockres;
>> +    int destroyed;
>>         clear_inode(inode);
>>         mlog(0, "inode %lu\n", inode->i_ino);
>>         ip = DLMFS_I(inode);
>> +    lockres = &ip->ip_lockres;
>>         if (S_ISREG(inode->i_mode)) {
>> -        status = user_dlm_destroy_lock(&ip->ip_lockres);
>> -        if (status < 0)
>> -            mlog_errno(status);
>> +        spin_lock(&lockres->l_lock);
>> +        destroyed = !!(lockres->l_flags & USER_LOCK_IN_TEARDOWN);
>> +        spin_unlock(&lockres->l_lock);
>
> This area code does the same work in user_dlm_destroy_lock(). Why not 
> to give another
> errno (e.g -EAGAIN) for user_dlm_destroy_lock when l_flags contains 
> USER_LOCK_IN_TEARDOWN.
> then change 'if (status < 0)' to 'if (status < 0 && status != -EAGAIN)'

I don't think we should do that. It's reasonable for 
user_dlm_destroy_lock() to return EBUSY in that case. EAGAIN is for the 
case, you invoke it second time you may succeed. That's not the case here.

Thanks,

Junxiao.

>
> Thanks,
> Heming
>
>> +        if (!destroyed) {
>> +            status = user_dlm_destroy_lock(lockres);
>> +            if (status < 0)
>> +                mlog_errno(status);
>> +        }
>>           iput(ip->ip_parent);
>>           goto clear_fields;
>>       }
>