From ea028ac92541ac30bf202ed94cb53eec2ea0c9d6 Mon Sep 17 00:00:00 2001 From: Andy Adamson Date: Fri, 4 Dec 2009 15:55:38 -0500 Subject: 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 Signed-off-by: Andy Adamson Signed-off-by: Trond Myklebust --- fs/nfs/nfs4proc.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) (limited to 'fs/nfs/nfs4proc.c') diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index fb62919f7f2c..c1bc9cad5e85 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -361,6 +361,16 @@ void nfs41_sequence_free_slot(const struct nfs_client *clp, } nfs4_free_slot(tbl, res->sr_slotid); res->sr_slotid = NFS4_MAX_SLOT_TABLE; + + /* Signal state manager thread if session is drained */ + if (test_bit(NFS4CLNT_SESSION_DRAINING, &clp->cl_state)) { + spin_lock(&tbl->slot_tbl_lock); + if (tbl->highest_used_slotid == -1) { + dprintk("%s COMPLETE: Session Drained\n", __func__); + complete(&clp->cl_session->complete); + } + spin_unlock(&tbl->slot_tbl_lock); + } } static void nfs41_sequence_done(struct nfs_client *clp, @@ -457,15 +467,11 @@ static int nfs41_setup_sequence(struct nfs4_session *session, spin_lock(&tbl->slot_tbl_lock); if (test_bit(NFS4CLNT_SESSION_RESET, &session->clp->cl_state)) { - if (tbl->highest_used_slotid != -1) { - rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL); - spin_unlock(&tbl->slot_tbl_lock); - dprintk("<-- %s: Session reset: draining\n", __func__); - return -EAGAIN; - } - - /* The slot table is empty; start the reset thread */ - dprintk("%s Session Reset\n", __func__); + /* + * The state manager will wait until the slot table is empty. + * Schedule the reset thread + */ + dprintk("%s Schedule Session Reset\n", __func__); rpc_sleep_on(&tbl->slot_tbl_waitq, task, NULL); nfs4_schedule_state_manager(session->clp); spin_unlock(&tbl->slot_tbl_lock); @@ -4506,6 +4512,7 @@ static int nfs4_reset_slot_tables(struct nfs4_session *session) 1); if (status) return status; + init_completion(&session->complete); status = nfs4_reset_slot_table(&session->bc_slot_table, session->bc_attrs.max_reqs, @@ -4608,6 +4615,7 @@ struct nfs4_session *nfs4_alloc_session(struct nfs_client *clp) * nfs_client struct */ clp->cl_cons_state = NFS_CS_SESSION_INITING; + init_completion(&session->complete); tbl = &session->fc_slot_table; spin_lock_init(&tbl->slot_tbl_lock); -- cgit v1.2.3