nfsd4: don't sleep in lease-break callback
The NFSv4 server's fl_break callback can sleep (dropping the BKL), in
order to allocate a new rpc task to send a recall to the client.
As far as I can tell this doesn't cause any races in the current code,
but the analysis is difficult. Also, the sleep here may complicate the
move away from the BKL.
So, just schedule some work to do the job for us instead. The work will
later also prove useful for restarting a call after the callback
information is changed.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 5051ade..adc51d1 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -198,6 +198,7 @@
atomic_set(&dp->dl_count, 1);
list_add(&dp->dl_perfile, &fp->fi_delegations);
list_add(&dp->dl_perclnt, &clp->cl_delegations);
+ INIT_WORK(&dp->dl_recall.cb_work, nfsd4_do_callback_rpc);
return dp;
}
@@ -679,21 +680,6 @@
return clp;
}
-static void
-shutdown_callback_client(struct nfs4_client *clp)
-{
- struct rpc_clnt *clnt = clp->cl_cb_conn.cb_client;
-
- if (clnt) {
- /*
- * Callback threads take a reference on the client, so there
- * should be no outstanding callbacks at this point.
- */
- clp->cl_cb_conn.cb_client = NULL;
- rpc_shutdown_client(clnt);
- }
-}
-
static inline void
free_client(struct nfs4_client *clp)
{
@@ -746,7 +732,7 @@
se_perclnt);
release_session(ses);
}
- shutdown_callback_client(clp);
+ nfsd4_set_callback_client(clp, NULL);
if (clp->cl_cb_xprt)
svc_xprt_put(clp->cl_cb_xprt);
put_nfs4_client(clp);
@@ -1392,7 +1378,7 @@
spin_unlock(&sessionid_lock);
/* wait for callbacks */
- shutdown_callback_client(ses->se_client);
+ nfsd4_set_callback_client(ses->se_client, NULL);
nfsd4_put_session(ses);
status = nfs_ok;
out:
@@ -4004,16 +3990,27 @@
static int
__nfs4_state_start(void)
{
+ int ret;
+
boot_time = get_seconds();
locks_start_grace(&nfsd4_manager);
printk(KERN_INFO "NFSD: starting %ld-second grace period\n",
nfsd4_grace);
+ ret = set_callback_cred();
+ if (ret)
+ return -ENOMEM;
laundry_wq = create_singlethread_workqueue("nfsd4");
if (laundry_wq == NULL)
return -ENOMEM;
+ ret = nfsd4_create_callback_queue();
+ if (ret)
+ goto out_free_laundry;
queue_delayed_work(laundry_wq, &laundromat_work, nfsd4_grace * HZ);
set_max_delegations();
- return set_callback_cred();
+ return 0;
+out_free_laundry:
+ destroy_workqueue(laundry_wq);
+ return ret;
}
int
@@ -4075,6 +4072,7 @@
nfs4_lock_state();
nfs4_release_reclaim();
__nfs4_state_shutdown();
+ nfsd4_destroy_callback_queue();
nfs4_unlock_state();
}