Commit bb6aeba736ba "NFSv4.x: Switch to using svc_set_num_threads()
to manage the callback threads" change nfs start/stop threads
through svc_set_num_threads().
It destroy old threads by SIGINT signal, but our nfs4_callback_svc()
isn't interruptible. So that, the callback threads will never be killed.
# mount -t nfs -overs=4.2 nfstestnic:/ /mnt/
# ps -ajx |grep NFS
2 5927 0 0 ? -1 S 0 0:00 [NFSv4 callback]
# umount /mnt
# ps -ajx |grep NFS
2 5927 0 0 ? -1 S 0 0:00 [NFSv4 callback]
# mount -t nfs -overs=4.2 nfstestnic:/ /mnt/
# umount /mnt
# ps -ajx |grep NFS
2 5927 0 0 ? -1 S 0 0:00 [NFSv4 callback]
2 5963 0 0 ? -1 S 0 0:00 [NFSv4 callback]
After one mount, there will be one callback thread left that cannot killed,
the same time, nfs.ko will never be unplugged.
Signed-off-by: Kinglong Mee <[email protected]>
---
fs/nfs/callback.c | 41 +++++++++++++++++++++++++++++++++++++----
1 file changed, 37 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 484bebc..0738470 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -73,6 +73,15 @@ nfs4_callback_svc(void *vrqstp)
int err;
struct svc_rqst *rqstp = vrqstp;
+ /*
+ * thread is spawned with all signals set to SIG_IGN, re-enable
+ * the ones that will bring down the thread
+ */
+ allow_signal(SIGKILL);
+ allow_signal(SIGHUP);
+ allow_signal(SIGINT);
+ allow_signal(SIGQUIT);
+
set_freezable();
while (!kthread_should_stop()) {
@@ -80,11 +89,19 @@ nfs4_callback_svc(void *vrqstp)
* Listen for a request on the socket
*/
err = svc_recv(rqstp, MAX_SCHEDULE_TIMEOUT);
- if (err == -EAGAIN || err == -EINTR)
+ if (err == -EAGAIN)
continue;
+ else if (err == -EINTR)
+ break;
svc_process(rqstp);
}
- return 0;
+
+ flush_signals(current);
+ rqstp->rq_server = NULL;
+
+ /* Release the thread */
+ svc_exit_thread(rqstp);
+ module_put_and_exit(0);
}
#if defined(CONFIG_NFS_V4_1)
@@ -100,6 +117,15 @@ nfs41_callback_svc(void *vrqstp)
int error;
DEFINE_WAIT(wq);
+ /*
+ * thread is spawned with all signals set to SIG_IGN, re-enable
+ * the ones that will bring down the thread
+ */
+ allow_signal(SIGKILL);
+ allow_signal(SIGHUP);
+ allow_signal(SIGINT);
+ allow_signal(SIGQUIT);
+
set_freezable();
while (!kthread_should_stop()) {
@@ -121,11 +147,18 @@ nfs41_callback_svc(void *vrqstp)
} else {
spin_unlock_bh(&serv->sv_cb_lock);
schedule();
+ if (signalled())
+ break;
finish_wait(&serv->sv_cb_waitq, &wq);
}
- flush_signals(current);
}
- return 0;
+
+ flush_signals(current);
+ rqstp->rq_server = NULL;
+
+ /* Release the thread */
+ svc_exit_thread(rqstp);
+ module_put_and_exit(0);
}
static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
--
2.9.3