Re: [Devel] [PATCH] nfs: abort delegation in dying VE

[Andrei Vagin]

On Wed, Nov 15, 2017 at 11:41:00AM -0800, Andrei Vagin wrote:
> On Wed, Nov 15, 2017 at 07:55:02PM +0300, Kirill Tkhai wrote:
> > On 15.11.2017 19:50, Stanislav Kinsburskiy wrote:
> > > Don't queue delegation request, if ve init is exiting.
> > > 
> > > https://jira.sw.ru/browse/PSBM-77061
> > > 
> > > Inspired-by: Kirill Tkhai 
> > > Signed-off-by: Stanislav Kinsburskiy 
> > > ---
> > >  fs/nfs/delegation.c |   16 +++-
> > >  1 file changed, 15 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
> > > index 66af497..2422754 100644
> > > --- a/fs/nfs/delegation.c
> > > +++ b/fs/nfs/delegation.c
> > > @@ -189,15 +189,29 @@ void nfs_inode_reclaim_delegation(struct inode 
> > > *inode, struct rpc_cred *cred,
> > >   nfs_inode_set_delegation(inode, cred, res);
> > >  }
> > >  
> > > +static bool ve_abort_delegation(struct inode *inode)
> > > +{
> > > + struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
> > > + struct rpc_xprt *xprt;
> > > +
> > > + rcu_read_lock();
> > > + xprt = rcu_dereference(clp->cl_rpcclient->cl_xprt);
> > > + rcu_read_unlock();
> > > +
> > > + return xprt->xprt_net->owner_ve->ve_netns == NULL;
> > 
> > Usually, memory pointed by a pointer, which was obtained via rcu, has to be 
> > used
> > in rcu_read_* brackets:
> > 
> > rcu_read_lock();
> > xprt = rcu_dereference(clp->cl_rpcclient->cl_xprt);
> > ret = (xprt->xprt_net->owner_ve->ve_netns == NULL);
> > rcu_read_unlock();
> > 
> > return ret;
> > 
> > If there is no an exception, we have to do something like above.
> 
> It is true when you want to dereference this pointer, otherwise I don't
> see any reason to take rcu_read_lock().

Oops, here is exectly this case. I didn't read the proposed code. Sorry.
> 
> > 
> > > +}
> > > +
> > >  static int nfs_do_return_delegation(struct inode *inode, struct 
> > > nfs_delegation *delegation, int issync)
> > >  {
> > >   int res = 0;
> > >  
> > > - if (!test_bit(NFS_DELEGATION_REVOKED, >flags))
> > > + if (!test_bit(NFS_DELEGATION_REVOKED, >flags) &&
> > > + !ve_abort_delegation(inode)) {
> > >   res = nfs4_proc_delegreturn(inode,
> > >   delegation->cred,
> > >   >stateid,
> > >   issync);
> > > + }
> > >   nfs_free_delegation(delegation);
> > >   return res;
> > >  }
> > > 
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Re: [Devel] [PATCH] nfs: abort delegation in dying VE

[Andrei Vagin]

On Wed, Nov 15, 2017 at 07:55:02PM +0300, Kirill Tkhai wrote:
> On 15.11.2017 19:50, Stanislav Kinsburskiy wrote:
> > Don't queue delegation request, if ve init is exiting.
> > 
> > https://jira.sw.ru/browse/PSBM-77061
> > 
> > Inspired-by: Kirill Tkhai 
> > Signed-off-by: Stanislav Kinsburskiy 
> > ---
> >  fs/nfs/delegation.c |   16 +++-
> >  1 file changed, 15 insertions(+), 1 deletion(-)
> > 
> > diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
> > index 66af497..2422754 100644
> > --- a/fs/nfs/delegation.c
> > +++ b/fs/nfs/delegation.c
> > @@ -189,15 +189,29 @@ void nfs_inode_reclaim_delegation(struct inode 
> > *inode, struct rpc_cred *cred,
> > nfs_inode_set_delegation(inode, cred, res);
> >  }
> >  
> > +static bool ve_abort_delegation(struct inode *inode)
> > +{
> > +   struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
> > +   struct rpc_xprt *xprt;
> > +
> > +   rcu_read_lock();
> > +   xprt = rcu_dereference(clp->cl_rpcclient->cl_xprt);
> > +   rcu_read_unlock();
> > +
> > +   return xprt->xprt_net->owner_ve->ve_netns == NULL;
> 
> Usually, memory pointed by a pointer, which was obtained via rcu, has to be 
> used
> in rcu_read_* brackets:
> 
> rcu_read_lock();
> xprt = rcu_dereference(clp->cl_rpcclient->cl_xprt);
> ret = (xprt->xprt_net->owner_ve->ve_netns == NULL);
> rcu_read_unlock();
> 
> return ret;
> 
> If there is no an exception, we have to do something like above.

It is true when you want to dereference this pointer, otherwise I don't
see any reason to take rcu_read_lock().

> 
> > +}
> > +
> >  static int nfs_do_return_delegation(struct inode *inode, struct 
> > nfs_delegation *delegation, int issync)
> >  {
> > int res = 0;
> >  
> > -   if (!test_bit(NFS_DELEGATION_REVOKED, >flags))
> > +   if (!test_bit(NFS_DELEGATION_REVOKED, >flags) &&
> > +   !ve_abort_delegation(inode)) {
> > res = nfs4_proc_delegreturn(inode,
> > delegation->cred,
> > >stateid,
> > issync);
> > +   }
> > nfs_free_delegation(delegation);
> > return res;
> >  }
> > 
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Re: [Devel] [PATCH] nfs: abort delegation in dying VE

[Kirill Tkhai]

On 15.11.2017 19:50, Stanislav Kinsburskiy wrote:
> Don't queue delegation request, if ve init is exiting.
> 
> https://jira.sw.ru/browse/PSBM-77061
> 
> Inspired-by: Kirill Tkhai 
> Signed-off-by: Stanislav Kinsburskiy 
> ---
>  fs/nfs/delegation.c |   16 +++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
> index 66af497..2422754 100644
> --- a/fs/nfs/delegation.c
> +++ b/fs/nfs/delegation.c
> @@ -189,15 +189,29 @@ void nfs_inode_reclaim_delegation(struct inode *inode, 
> struct rpc_cred *cred,
>   nfs_inode_set_delegation(inode, cred, res);
>  }
>  
> +static bool ve_abort_delegation(struct inode *inode)
> +{
> + struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
> + struct rpc_xprt *xprt;
> +
> + rcu_read_lock();
> + xprt = rcu_dereference(clp->cl_rpcclient->cl_xprt);
> + rcu_read_unlock();
> +
> + return xprt->xprt_net->owner_ve->ve_netns == NULL;

Usually, memory pointed by a pointer, which was obtained via rcu, has to be used
in rcu_read_* brackets:

rcu_read_lock();
xprt = rcu_dereference(clp->cl_rpcclient->cl_xprt);
ret = (xprt->xprt_net->owner_ve->ve_netns == NULL);
rcu_read_unlock();

return ret;

If there is no an exception, we have to do something like above.

> +}
> +
>  static int nfs_do_return_delegation(struct inode *inode, struct 
> nfs_delegation *delegation, int issync)
>  {
>   int res = 0;
>  
> - if (!test_bit(NFS_DELEGATION_REVOKED, >flags))
> + if (!test_bit(NFS_DELEGATION_REVOKED, >flags) &&
> + !ve_abort_delegation(inode)) {
>   res = nfs4_proc_delegreturn(inode,
>   delegation->cred,
>   >stateid,
>   issync);
> + }
>   nfs_free_delegation(delegation);
>   return res;
>  }
> 
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[Devel] [PATCH] nfs: abort delegation in dying VE

[Stanislav Kinsburskiy]

Don't queue delegation request, if ve init is exiting.

https://jira.sw.ru/browse/PSBM-77061

Inspired-by: Kirill Tkhai 
Signed-off-by: Stanislav Kinsburskiy 
---
 fs/nfs/delegation.c |   16 +++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 66af497..2422754 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -189,15 +189,29 @@ void nfs_inode_reclaim_delegation(struct inode *inode, 
struct rpc_cred *cred,
nfs_inode_set_delegation(inode, cred, res);
 }
 
+static bool ve_abort_delegation(struct inode *inode)
+{
+   struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
+   struct rpc_xprt *xprt;
+
+   rcu_read_lock();
+   xprt = rcu_dereference(clp->cl_rpcclient->cl_xprt);
+   rcu_read_unlock();
+
+   return xprt->xprt_net->owner_ve->ve_netns == NULL;
+}
+
 static int nfs_do_return_delegation(struct inode *inode, struct nfs_delegation 
*delegation, int issync)
 {
int res = 0;
 
-   if (!test_bit(NFS_DELEGATION_REVOKED, >flags))
+   if (!test_bit(NFS_DELEGATION_REVOKED, >flags) &&
+   !ve_abort_delegation(inode)) {
res = nfs4_proc_delegreturn(inode,
delegation->cred,
>stateid,
issync);
+   }
nfs_free_delegation(delegation);
return res;
 }

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