• Trond Myklebust's avatar
    NFSv4.1: Fix the callback 'highest_used_slotid' behaviour · 55a67399
    Trond Myklebust authored
    Currently, there is no guarantee that we will call nfs4_cb_take_slot() even
    though nfs4_callback_compound() will consistently call
    nfs4_cb_free_slot() provided the cb_process_state has set the 'clp' field.
    The result is that we can trigger the BUG_ON() upon the next call to
    nfs4_cb_take_slot().
    
    This patch fixes the above problem by using the slot id that was taken in
    the CB_SEQUENCE operation as a flag for whether or not we need to call
    nfs4_cb_free_slot().
    It also fixes an atomicity problem: we need to set tbl->highest_used_slotid
    atomically with the check for NFS4_SESSION_DRAINING, otherwise we end up
    racing with the various tests in nfs4_begin_drain_session().
    
    Cc: stable@kernel.org [2.6.38+]
    Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
    55a67399
callback_xdr.c 24.7 KB