diff mbox series

[RFC,v16,04/11] NFSD: Update nfsd_breaker_owns_lease() to handle courtesy clients

Message ID 1647051215-2873-5-git-send-email-dai.ngo@oracle.com (mailing list archive)
State New, archived
Headers show
Series NFSD: Initial implementation of NFSv4 Courteous Server | expand

Commit Message

Dai Ngo March 12, 2022, 2:13 a.m. UTC
Update nfsd_breaker_owns_lease() to handle delegation conflict
with courtesy clients. If conflict was caused by courtesy client
then discard the courtesy client by setting CLIENT_EXPIRED and
return conflict resolved. Client with CLIENT_EXPIRED is expired
by the laundromat.

Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
---
 fs/nfsd/nfs4state.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

Comments

Chuck Lever March 13, 2022, 4:04 p.m. UTC | #1
> On Mar 11, 2022, at 9:13 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> 
> Update nfsd_breaker_owns_lease() to handle delegation conflict
> with courtesy clients. If conflict was caused by courtesy client
> then discard the courtesy client by setting CLIENT_EXPIRED and
> return conflict resolved. Client with CLIENT_EXPIRED is expired
> by the laundromat.
> 
> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> ---
> fs/nfsd/nfs4state.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 583ac807e98d..2beb0972de88 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -4713,6 +4713,28 @@ nfsd_break_deleg_cb(struct file_lock *fl)
> 	return ret;
> }
> 
> +static bool
> +nfs4_check_and_expire_courtesy_client(struct nfs4_client *clp)
> +{
> +	/*
> +	 * need to sync with courtesy client trying to reconnect using
> +	 * the cl_cs_lock, nn->client_lock can not be used since this
> +	 * function is called with the fl_lck held.
> +	 */
> +	spin_lock(&clp->cl_cs_lock);
> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
> +		spin_unlock(&clp->cl_cs_lock);
> +		return true;
> +	}
> +	if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> +		set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
> +		spin_unlock(&clp->cl_cs_lock);
> +		return true;
> +	}
> +	spin_unlock(&clp->cl_cs_lock);
> +	return false;
> +}
> +
> /**
>  * nfsd_breaker_owns_lease - Check if lease conflict was resolved
>  * @fl: Lock state to check
> @@ -4727,6 +4749,10 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
> 	struct svc_rqst *rqst;
> 	struct nfs4_client *clp;
> 
> +	clp = dl->dl_stid.sc_client;
> +	if (nfs4_check_and_expire_courtesy_client(clp))

Since you'll need to fix the kernel robot issue in 1/11, when you
repost, can you also just pass dl->dl_stid.sc_client directly to
nfs4_check_and_expire_courtesy_client() here?


> +		return true;
> +
> 	if (!i_am_nfsd())
> 		return false;
> 	rqst = kthread_data(current);
> -- 
> 2.9.5
> 

--
Chuck Lever
J. Bruce Fields March 15, 2022, 3:13 p.m. UTC | #2
On Sun, Mar 13, 2022 at 04:04:21PM +0000, Chuck Lever III wrote:
> 
> 
> > On Mar 11, 2022, at 9:13 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
> > 
> > Update nfsd_breaker_owns_lease() to handle delegation conflict
> > with courtesy clients. If conflict was caused by courtesy client
> > then discard the courtesy client by setting CLIENT_EXPIRED and
> > return conflict resolved. Client with CLIENT_EXPIRED is expired
> > by the laundromat.
> > 
> > Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
> > ---
> > fs/nfsd/nfs4state.c | 26 ++++++++++++++++++++++++++
> > 1 file changed, 26 insertions(+)
> > 
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index 583ac807e98d..2beb0972de88 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -4713,6 +4713,28 @@ nfsd_break_deleg_cb(struct file_lock *fl)
> > 	return ret;
> > }
> > 
> > +static bool
> > +nfs4_check_and_expire_courtesy_client(struct nfs4_client *clp)
> > +{
> > +	/*
> > +	 * need to sync with courtesy client trying to reconnect using
> > +	 * the cl_cs_lock, nn->client_lock can not be used since this
> > +	 * function is called with the fl_lck held.
> > +	 */
> > +	spin_lock(&clp->cl_cs_lock);
> > +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
> > +		spin_unlock(&clp->cl_cs_lock);
> > +		return true;
> > +	}
> > +	if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
> > +		set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
> > +		spin_unlock(&clp->cl_cs_lock);
> > +		return true;
> > +	}
> > +	spin_unlock(&clp->cl_cs_lock);

Same comment as on the previous patch.  ALso, this is the second time
we've used this logic, please define a

	static bool expire_client_if_courtesy(struct nfs4_client *clp)

and call it from both places.

> > +	return false;
> > +}
> > +
> > /**
> >  * nfsd_breaker_owns_lease - Check if lease conflict was resolved
> >  * @fl: Lock state to check
> > @@ -4727,6 +4749,10 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
> > 	struct svc_rqst *rqst;
> > 	struct nfs4_client *clp;
> > 
> > +	clp = dl->dl_stid.sc_client;
> > +	if (nfs4_check_and_expire_courtesy_client(clp))
> 
> Since you'll need to fix the kernel robot issue in 1/11, when you
> repost, can you also just pass dl->dl_stid.sc_client directly to
> nfs4_check_and_expire_courtesy_client() here?

Agreed.

This client is quite different from the one we look up from the task a
little later, and I'd just rather not have both represented by the same
variable.

--b.
Dai Ngo March 15, 2022, 4:27 p.m. UTC | #3
On 3/15/22 8:13 AM, Bruce Fields wrote:
> On Sun, Mar 13, 2022 at 04:04:21PM +0000, Chuck Lever III wrote:
>>
>>> On Mar 11, 2022, at 9:13 PM, Dai Ngo <dai.ngo@oracle.com> wrote:
>>>
>>> Update nfsd_breaker_owns_lease() to handle delegation conflict
>>> with courtesy clients. If conflict was caused by courtesy client
>>> then discard the courtesy client by setting CLIENT_EXPIRED and
>>> return conflict resolved. Client with CLIENT_EXPIRED is expired
>>> by the laundromat.
>>>
>>> Signed-off-by: Dai Ngo <dai.ngo@oracle.com>
>>> ---
>>> fs/nfsd/nfs4state.c | 26 ++++++++++++++++++++++++++
>>> 1 file changed, 26 insertions(+)
>>>
>>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>>> index 583ac807e98d..2beb0972de88 100644
>>> --- a/fs/nfsd/nfs4state.c
>>> +++ b/fs/nfsd/nfs4state.c
>>> @@ -4713,6 +4713,28 @@ nfsd_break_deleg_cb(struct file_lock *fl)
>>> 	return ret;
>>> }
>>>
>>> +static bool
>>> +nfs4_check_and_expire_courtesy_client(struct nfs4_client *clp)
>>> +{
>>> +	/*
>>> +	 * need to sync with courtesy client trying to reconnect using
>>> +	 * the cl_cs_lock, nn->client_lock can not be used since this
>>> +	 * function is called with the fl_lck held.
>>> +	 */
>>> +	spin_lock(&clp->cl_cs_lock);
>>> +	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
>>> +		spin_unlock(&clp->cl_cs_lock);
>>> +		return true;
>>> +	}
>>> +	if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
>>> +		set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
>>> +		spin_unlock(&clp->cl_cs_lock);
>>> +		return true;
>>> +	}
>>> +	spin_unlock(&clp->cl_cs_lock);
> Same comment as on the previous patch.  ALso, this is the second time
> we've used this logic, please define a
>
> 	static bool expire_client_if_courtesy(struct nfs4_client *clp)
>
> and call it from both places.

I will replace the similar code in nfsd4_lm_lock_expired with
a call to nfs4_check_and_expire_courtesy_client.

>
>>> +	return false;
>>> +}
>>> +
>>> /**
>>>   * nfsd_breaker_owns_lease - Check if lease conflict was resolved
>>>   * @fl: Lock state to check
>>> @@ -4727,6 +4749,10 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
>>> 	struct svc_rqst *rqst;
>>> 	struct nfs4_client *clp;
>>>
>>> +	clp = dl->dl_stid.sc_client;
>>> +	if (nfs4_check_and_expire_courtesy_client(clp))
>> Since you'll need to fix the kernel robot issue in 1/11, when you
>> repost, can you also just pass dl->dl_stid.sc_client directly to
>> nfs4_check_and_expire_courtesy_client() here?
> Agreed.
>
> This client is quite different from the one we look up from the task a
> little later, and I'd just rather not have both represented by the same
> variable.

fix in v17.

-Dai

>
> --b.
diff mbox series

Patch

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 583ac807e98d..2beb0972de88 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4713,6 +4713,28 @@  nfsd_break_deleg_cb(struct file_lock *fl)
 	return ret;
 }
 
+static bool
+nfs4_check_and_expire_courtesy_client(struct nfs4_client *clp)
+{
+	/*
+	 * need to sync with courtesy client trying to reconnect using
+	 * the cl_cs_lock, nn->client_lock can not be used since this
+	 * function is called with the fl_lck held.
+	 */
+	spin_lock(&clp->cl_cs_lock);
+	if (test_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags)) {
+		spin_unlock(&clp->cl_cs_lock);
+		return true;
+	}
+	if (test_bit(NFSD4_CLIENT_COURTESY, &clp->cl_flags)) {
+		set_bit(NFSD4_CLIENT_EXPIRED, &clp->cl_flags);
+		spin_unlock(&clp->cl_cs_lock);
+		return true;
+	}
+	spin_unlock(&clp->cl_cs_lock);
+	return false;
+}
+
 /**
  * nfsd_breaker_owns_lease - Check if lease conflict was resolved
  * @fl: Lock state to check
@@ -4727,6 +4749,10 @@  static bool nfsd_breaker_owns_lease(struct file_lock *fl)
 	struct svc_rqst *rqst;
 	struct nfs4_client *clp;
 
+	clp = dl->dl_stid.sc_client;
+	if (nfs4_check_and_expire_courtesy_client(clp))
+		return true;
+
 	if (!i_am_nfsd())
 		return false;
 	rqst = kthread_data(current);