Signed-off-by: Alexandros Batsakis <[email protected]>
---
fs/nfs/client.c | 38 ++++++++++----------------------------
fs/nfs/nfs4_fs.h | 1 +
fs/nfs/nfs4proc.c | 3 +++
fs/nfs/nfs4state.c | 17 ++++++++++++++++-
4 files changed, 30 insertions(+), 29 deletions(-)
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index d0b060a..3efde50 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -164,19 +164,6 @@ error_0:
return ERR_PTR(err);
}
-static void nfs4_shutdown_client(struct nfs_client *clp)
-{
-#ifdef CONFIG_NFS_V4
- if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
- nfs4_kill_renewd(clp);
- BUG_ON(!RB_EMPTY_ROOT(&clp->cl_state_owners));
- if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
- nfs_idmap_delete(clp);
-
- rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
-#endif
-}
-
/*
* Destroy the NFS4 callback service
*/
@@ -188,22 +175,18 @@ static void nfs4_destroy_callback(struct nfs_client *clp)
#endif /* CONFIG_NFS_V4 */
}
-/*
- * Clears/puts all minor version specific parts from an nfs_client struct
- * reverting it to minorversion 0.
- */
-static void nfs4_clear_client_minor_version(struct nfs_client *clp)
+static void nfs4_shutdown_client(struct nfs_client *clp)
{
-#ifdef CONFIG_NFS_V4_1
- if (nfs4_has_session(clp)) {
- nfs4_destroy_session(clp->cl_session);
- clp->cl_session = NULL;
- }
-
- clp->cl_call_sync = _nfs4_call_sync;
-#endif /* CONFIG_NFS_V4_1 */
-
+#ifdef CONFIG_NFS_V4
+ if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
+ nfs4_kill_renewd(clp);
+ nfs4_clear_session(clp);
nfs4_destroy_callback(clp);
+ if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
+ nfs_idmap_delete(clp);
+
+ rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
+#endif
}
/*
@@ -213,7 +196,6 @@ static void nfs_free_client(struct nfs_client *clp)
{
dprintk("--> nfs_free_client(%u)\n", clp->rpc_ops->version);
- nfs4_clear_client_minor_version(clp);
nfs4_shutdown_client(clp);
nfs_fscache_release_client_cookie(clp);
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index cd93dfc..fbeec98 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -263,6 +263,7 @@ extern void nfs4_renew_state(struct work_struct *);
/* nfs4state.c */
struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client *clp);
struct rpc_cred *nfs4_get_renew_cred_locked(struct nfs_client *clp);
+void nfs4_clear_session(struct nfs_client *clp);
#if defined(CONFIG_NFS_V4_1)
struct rpc_cred *nfs4_get_machine_cred_locked(struct nfs_client *clp);
struct rpc_cred *nfs4_get_exchange_id_cred(struct nfs_client *clp);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ec9f075..a99c7d3 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -5004,6 +5004,9 @@ void nfs41_sequence_call_done(struct rpc_task *task, void *data)
{
struct nfs_client *clp = (struct nfs_client *)data;
+ if (!nfs4_has_session(clp))
+ return;
+
nfs41_sequence_done(clp, task->tk_msg.rpc_resp, task->tk_status);
if (task->tk_status < 0) {
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 069dcb3..dc3cfbf 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -199,6 +199,16 @@ struct rpc_cred *nfs4_get_exchange_id_cred(struct nfs_client *clp)
return cred;
}
+void nfs4_clear_session(struct nfs_client *clp)
+{
+ if (nfs4_has_session(clp)) {
+ nfs4_begin_drain_session(clp);
+ nfs4_destroy_session(clp->cl_session);
+ clp->cl_session = NULL;
+ }
+ clp->cl_call_sync = _nfs4_call_sync;
+}
+
#endif /* CONFIG_NFS_V4_1 */
struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client *clp)
@@ -878,7 +888,11 @@ void nfs4_schedule_state_manager(struct nfs_client *clp)
if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0)
return;
__module_get(THIS_MODULE);
- atomic_inc(&clp->cl_count);
+ if (!atomic_inc_not_zero(&clp->cl_count)) {
+ nfs4_clear_state_manager_bit(clp);
+ module_put(THIS_MODULE);
+ return;
+ }
task = kthread_run(nfs4_run_state_manager, clp, "%s-manager",
rpc_peeraddr2str(clp->cl_rpcclient,
RPC_DISPLAY_ADDR));
@@ -1336,6 +1350,7 @@ static int nfs4_recall_slot(struct nfs_client *clp)
#else /* CONFIG_NFS_V4_1 */
static int nfs4_reset_session(struct nfs_client *clp) { return 0; }
static int nfs4_end_drain_session(struct nfs_client *clp) { return 0; }
+void nfs4_clear_session(struct nfs_client *clp) { return 0; }
static int nfs4_recall_slot(struct nfs_client *clp) { return 0; }
#endif /* CONFIG_NFS_V4_1 */
--
1.6.2.5
On Thu, 2010-01-21 at 20:51 -0800, Alexandros Batsakis wrote:
> struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client *clp)
> @@ -878,7 +888,11 @@ void nfs4_schedule_state_manager(struct nfs_client *clp)
> if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0)
> return;
> __module_get(THIS_MODULE);
> - atomic_inc(&clp->cl_count);
> + if (!atomic_inc_not_zero(&clp->cl_count)) {
> + nfs4_clear_state_manager_bit(clp);
> + module_put(THIS_MODULE);
> + return;
> + }
The use of atomic_inc_not_zero() should not be necessary here. Anybody
who is calling this function without holding a reference to clp is doing
something fundamentally wrong.
Trond
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On Fri, 2010-01-22 at 11:30 -0800, Batsakis, Alexandros wrote:
>
> > -----Original Message-----
> > From: Myklebust, Trond
> > Sent: Friday, January 22, 2010 10:47 AM
> > To: Batsakis, Alexandros
> > Cc: [email protected]; Myklebust, Trond
> > Subject: Re: [PATCH 1/1] nfs: fix race between renewd, umount, and the
> > state manager in V4.1
> >
> > On Thu, 2010-01-21 at 20:51 -0800, Alexandros Batsakis wrote:
> >
> > > struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client *clp)
> > > @@ -878,7 +888,11 @@ void nfs4_schedule_state_manager(struct
> > nfs_client *clp)
> > > if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) !=
> > 0)
> > > return;
> > > __module_get(THIS_MODULE);
> > > - atomic_inc(&clp->cl_count);
> > > + if (!atomic_inc_not_zero(&clp->cl_count)) {
> > > + nfs4_clear_state_manager_bit(clp);
> > > + module_put(THIS_MODULE);
> > > + return;
> > > + }
> >
> > The use of atomic_inc_not_zero() should not be necessary here. Anybody
> > who is calling this function without holding a reference to clp is
> > doing
> > something fundamentally wrong.
>
> Agreed, but how can we enforce this (especially with asynchronous RPC) ?
> For example what will happen if _during_ umount (after nfs_put_client()), an NFS call that was sleeping e.g. waiting for the server to come up, reaches the server and the response causes the state manager to start ?
> Any ideas ?
What would you expect to see running during umount? Nobody can be
holding a reference to the vfsmount at that point, so there should be no
active processes around to make NFS calls.
Trond
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On Fri, 2010-01-22 at 12:01 -0800, Batsakis, Alexandros wrote:
>
> > -----Original Message-----
> > From: Myklebust, Trond
> > Sent: Friday, January 22, 2010 11:42 AM
> > To: Batsakis, Alexandros
> > Cc: [email protected]
> > Subject: RE: [PATCH 1/1] nfs: fix race between renewd, umount, and the
> > state manager in V4.1
> >
> > On Fri, 2010-01-22 at 11:30 -0800, Batsakis, Alexandros wrote:
> > >
> > > > -----Original Message-----
> > > > From: Myklebust, Trond
> > > > Sent: Friday, January 22, 2010 10:47 AM
> > > > To: Batsakis, Alexandros
> > > > Cc: [email protected]; Myklebust, Trond
> > > > Subject: Re: [PATCH 1/1] nfs: fix race between renewd, umount, and
> > the
> > > > state manager in V4.1
> > > >
> > > > On Thu, 2010-01-21 at 20:51 -0800, Alexandros Batsakis wrote:
> > > >
> > > > > struct rpc_cred *nfs4_get_setclientid_cred(struct nfs_client
> > *clp)
> > > > > @@ -878,7 +888,11 @@ void nfs4_schedule_state_manager(struct
> > > > nfs_client *clp)
> > > > > if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp-
> > >cl_state) !=
> > > > 0)
> > > > > return;
> > > > > __module_get(THIS_MODULE);
> > > > > - atomic_inc(&clp->cl_count);
> > > > > + if (!atomic_inc_not_zero(&clp->cl_count)) {
> > > > > + nfs4_clear_state_manager_bit(clp);
> > > > > + module_put(THIS_MODULE);
> > > > > + return;
> > > > > + }
> > > >
> > > > The use of atomic_inc_not_zero() should not be necessary here.
> > Anybody
> > > > who is calling this function without holding a reference to clp is
> > > > doing
> > > > something fundamentally wrong.
> > >
> > > Agreed, but how can we enforce this (especially with asynchronous
> > RPC) ?
> > > For example what will happen if _during_ umount (after
> > nfs_put_client()), an NFS call that was sleeping e.g. waiting for the
> > server to come up, reaches the server and the response causes the state
> > manager to start ?
> > > Any ideas ?
> >
> > What would you expect to see running during umount? Nobody can be
> > holding a reference to the vfsmount at that point, so there should be
> > no
> > active processes around to make NFS calls.
> >
>
> renewd is still running and even if we kill the daemon, maybe there is a sequence_done pending
Then the correct thing to do is to fix the renewd kill process. Once
that is done, there should be no reason for any sequence_done calls to
be pending (see reason above).
Trond
On Fri, 2010-01-22 at 15:11 -0500, Trond Myklebust wrote:
> Then the correct thing to do is to fix the renewd kill process. Once
> that is done, there should be no reason for any sequence_done calls to
> be pending (see reason above).
IOW: we should add a call to atomic_inc_not_zero(&clp->cl_count) in
nfs4_proc_async_renew()/nfs41_proc_async_sequence(), and have them fail
if that attempt to grab a reference fails. Then we should add a call to
nfs_put_client() in their .rpc_release method.
Trond
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