nfs41: nfs41: fix state manager deadlock in session reset
If the session is reset during state recovery, the state manager thread can
sleep on the slot_tbl_waitq causing a deadlock.
Add a completion framework to the session. Have the state manager thread set
a new session state (NFS4CLNT_SESSION_DRAINING) and wait for the session slot
table to drain.
Signal the state manager thread in nfs41_sequence_free_slot when the
NFS4CLNT_SESSION_DRAINING bit is set and the session is drained.
Reported-by: Trond Myklebust <trond@netapp.com>
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index f56f6be..3c14335 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1181,8 +1181,23 @@
static int nfs4_reset_session(struct nfs_client *clp)
{
+ struct nfs4_session *ses = clp->cl_session;
+ struct nfs4_slot_table *tbl = &ses->fc_slot_table;
int status;
+ INIT_COMPLETION(ses->complete);
+ spin_lock(&tbl->slot_tbl_lock);
+ if (tbl->highest_used_slotid != -1) {
+ set_bit(NFS4CLNT_SESSION_DRAINING, &clp->cl_state);
+ spin_unlock(&tbl->slot_tbl_lock);
+ status = wait_for_completion_interruptible(&ses->complete);
+ clear_bit(NFS4CLNT_SESSION_DRAINING, &clp->cl_state);
+ if (status) /* -ERESTARTSYS */
+ goto out;
+ } else {
+ spin_unlock(&tbl->slot_tbl_lock);
+ }
+
status = nfs4_proc_destroy_session(clp->cl_session);
if (status && status != -NFS4ERR_BADSESSION &&
status != -NFS4ERR_DEADSESSION) {