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* [PATCH] cifs: remove the retry in cifs_poxis_lock_set
@ 2020-06-24  7:10 yangerkun
  2020-06-30 12:24 ` yangerkun
  0 siblings, 1 reply; 4+ messages in thread
From: yangerkun @ 2020-06-24  7:10 UTC (permalink / raw)
  To: sfrench, jlayton, neilb, neilb; +Cc: linux-cifs, samba-technical, linux-fsdevel

The caller of cifs_posix_lock_set will do retry(like
fcntl_setlk64->do_lock_file_wait) if we will wait for any file_lock.
So the retry in cifs_poxis_lock_set seems duplicated, remove it to
make a cleanup.

Signed-off-by: yangerkun <yangerkun@huawei.com>
---
 fs/cifs/file.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 9b0f8f33f832..2c9c24b1805d 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1162,7 +1162,6 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
 	if ((flock->fl_flags & FL_POSIX) == 0)
 		return rc;
 
-try_again:
 	cifs_down_write(&cinode->lock_sem);
 	if (!cinode->can_cache_brlcks) {
 		up_write(&cinode->lock_sem);
@@ -1171,13 +1170,6 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
 
 	rc = posix_lock_file(file, flock, NULL);
 	up_write(&cinode->lock_sem);
-	if (rc == FILE_LOCK_DEFERRED) {
-		rc = wait_event_interruptible(flock->fl_wait,
-					list_empty(&flock->fl_blocked_member));
-		if (!rc)
-			goto try_again;
-		locks_delete_block(flock);
-	}
 	return rc;
 }
 
-- 
2.25.4


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] cifs: remove the retry in cifs_poxis_lock_set
  2020-06-24  7:10 [PATCH] cifs: remove the retry in cifs_poxis_lock_set yangerkun
@ 2020-06-30 12:24 ` yangerkun
  2020-06-30 22:34   ` NeilBrown
  0 siblings, 1 reply; 4+ messages in thread
From: yangerkun @ 2020-06-30 12:24 UTC (permalink / raw)
  To: sfrench, jlayton, neilb, neilb; +Cc: linux-cifs, samba-technical, linux-fsdevel

Ping...

在 2020/6/24 15:10, yangerkun 写道:
> The caller of cifs_posix_lock_set will do retry(like
> fcntl_setlk64->do_lock_file_wait) if we will wait for any file_lock.
> So the retry in cifs_poxis_lock_set seems duplicated, remove it to
> make a cleanup.
> 
> Signed-off-by: yangerkun <yangerkun@huawei.com>
> ---
>   fs/cifs/file.c | 8 --------
>   1 file changed, 8 deletions(-)
> 
> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
> index 9b0f8f33f832..2c9c24b1805d 100644
> --- a/fs/cifs/file.c
> +++ b/fs/cifs/file.c
> @@ -1162,7 +1162,6 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
>   	if ((flock->fl_flags & FL_POSIX) == 0)
>   		return rc;
>   
> -try_again:
>   	cifs_down_write(&cinode->lock_sem);
>   	if (!cinode->can_cache_brlcks) {
>   		up_write(&cinode->lock_sem);
> @@ -1171,13 +1170,6 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
>   
>   	rc = posix_lock_file(file, flock, NULL);
>   	up_write(&cinode->lock_sem);
> -	if (rc == FILE_LOCK_DEFERRED) {
> -		rc = wait_event_interruptible(flock->fl_wait,
> -					list_empty(&flock->fl_blocked_member));
> -		if (!rc)
> -			goto try_again;
> -		locks_delete_block(flock);
> -	}
>   	return rc;
>   }
>   
> 


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] cifs: remove the retry in cifs_poxis_lock_set
  2020-06-30 12:24 ` yangerkun
@ 2020-06-30 22:34   ` NeilBrown
  2020-07-01  1:24     ` yangerkun
  0 siblings, 1 reply; 4+ messages in thread
From: NeilBrown @ 2020-06-30 22:34 UTC (permalink / raw)
  To: yangerkun, sfrench, jlayton, neilb
  Cc: linux-cifs, samba-technical, linux-fsdevel


[-- Attachment #1: Type: text/plain, Size: 1860 bytes --]

On Tue, Jun 30 2020, yangerkun wrote:

> Ping...
>
> 在 2020/6/24 15:10, yangerkun 写道:
>> The caller of cifs_posix_lock_set will do retry(like
>> fcntl_setlk64->do_lock_file_wait) if we will wait for any file_lock.
>> So the retry in cifs_poxis_lock_set seems duplicated, remove it to
>> make a cleanup.

If cifs_posix_try_lock() returns FILE_LOCK_DEFERRED (which it might
after your patch), then cifs_setlk() will check the return value:

		if (!rc || rc < 0)
			return rc;

These tests will fail (as FILE_LOCK_DEFERRED is 1) and so it will
continue on as though the lock was granted.

So I think your patch is wrong.
However I think your goal is correct.  cifs shouldn't be waiting.
No other filesystem waits when it gets FILE_LOCK_DEFERRED.

So maybe try to fix up your patch.

Thanks,
NeilBrown


>> 
>> Signed-off-by: yangerkun <yangerkun@huawei.com>
>> ---
>>   fs/cifs/file.c | 8 --------
>>   1 file changed, 8 deletions(-)
>> 
>> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
>> index 9b0f8f33f832..2c9c24b1805d 100644
>> --- a/fs/cifs/file.c
>> +++ b/fs/cifs/file.c
>> @@ -1162,7 +1162,6 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
>>   	if ((flock->fl_flags & FL_POSIX) == 0)
>>   		return rc;
>>   
>> -try_again:
>>   	cifs_down_write(&cinode->lock_sem);
>>   	if (!cinode->can_cache_brlcks) {
>>   		up_write(&cinode->lock_sem);
>> @@ -1171,13 +1170,6 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
>>   
>>   	rc = posix_lock_file(file, flock, NULL);
>>   	up_write(&cinode->lock_sem);
>> -	if (rc == FILE_LOCK_DEFERRED) {
>> -		rc = wait_event_interruptible(flock->fl_wait,
>> -					list_empty(&flock->fl_blocked_member));
>> -		if (!rc)
>> -			goto try_again;
>> -		locks_delete_block(flock);
>> -	}
>>   	return rc;
>>   }
>>   
>> 

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] cifs: remove the retry in cifs_poxis_lock_set
  2020-06-30 22:34   ` NeilBrown
@ 2020-07-01  1:24     ` yangerkun
  0 siblings, 0 replies; 4+ messages in thread
From: yangerkun @ 2020-07-01  1:24 UTC (permalink / raw)
  To: NeilBrown, sfrench, jlayton, neilb
  Cc: linux-cifs, samba-technical, linux-fsdevel



在 2020/7/1 6:34, NeilBrown 写道:
> On Tue, Jun 30 2020, yangerkun wrote:
> 
>> Ping...
>>
>> 在 2020/6/24 15:10, yangerkun 写道:
>>> The caller of cifs_posix_lock_set will do retry(like
>>> fcntl_setlk64->do_lock_file_wait) if we will wait for any file_lock.
>>> So the retry in cifs_poxis_lock_set seems duplicated, remove it to
>>> make a cleanup.
> 
> If cifs_posix_try_lock() returns FILE_LOCK_DEFERRED (which it might
> after your patch), then cifs_setlk() will check the return value:
> 
> 		if (!rc || rc < 0)
> 			return rc;
> 
> These tests will fail (as FILE_LOCK_DEFERRED is 1) and so it will
> continue on as though the lock was granted.
> 
> So I think your patch is wrong.
> However I think your goal is correct.  cifs shouldn't be waiting.
> No other filesystem waits when it gets FILE_LOCK_DEFERRED.
> 
> So maybe try to fix up your patch.

Yes, we should check FILE_LOCK_DEFERRED in cifs_setlk after this patch.
Also we may change 'int rc = 1;' exists in cifs_posix_lock_set since
FILE_LOCK_DEFERRED equals to 1.

I will send a v2 and thanks a lot for your review!

Thanks,
Kun.

> Thanks,
> NeilBrown
> 
> 
>>>
>>> Signed-off-by: yangerkun <yangerkun@huawei.com>
>>> ---
>>>    fs/cifs/file.c | 8 --------
>>>    1 file changed, 8 deletions(-)
>>>
>>> diff --git a/fs/cifs/file.c b/fs/cifs/file.c
>>> index 9b0f8f33f832..2c9c24b1805d 100644
>>> --- a/fs/cifs/file.c
>>> +++ b/fs/cifs/file.c
>>> @@ -1162,7 +1162,6 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
>>>    	if ((flock->fl_flags & FL_POSIX) == 0)
>>>    		return rc;
>>>    
>>> -try_again:
>>>    	cifs_down_write(&cinode->lock_sem);
>>>    	if (!cinode->can_cache_brlcks) {
>>>    		up_write(&cinode->lock_sem);
>>> @@ -1171,13 +1170,6 @@ cifs_posix_lock_set(struct file *file, struct file_lock *flock)
>>>    
>>>    	rc = posix_lock_file(file, flock, NULL);
>>>    	up_write(&cinode->lock_sem);
>>> -	if (rc == FILE_LOCK_DEFERRED) {
>>> -		rc = wait_event_interruptible(flock->fl_wait,
>>> -					list_empty(&flock->fl_blocked_member));
>>> -		if (!rc)
>>> -			goto try_again;
>>> -		locks_delete_block(flock);
>>> -	}
>>>    	return rc;
>>>    }
>>>    
>>>


^ permalink raw reply	[flat|nested] 4+ messages in thread

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Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-24  7:10 [PATCH] cifs: remove the retry in cifs_poxis_lock_set yangerkun
2020-06-30 12:24 ` yangerkun
2020-06-30 22:34   ` NeilBrown
2020-07-01  1:24     ` yangerkun

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