NFS: Use raw_write_seqcount_begin/end int nfs4_reclaim_open_state

The addition of lockdep code to write_seqcount_begin/end has lead to
a bunch of false positive claims of ABBA deadlocks with the so_lock
spinlock. Audits show that this simply cannot happen because the
read side code does not spin while holding so_lock.

Cc: <stable@vger.kernel.org> # 3.13.x
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 2349518..2127514 100644 (file)
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -1456,7 +1456,7 @@ static int nfs4_reclaim_open_state(struct nfs4_state_owner *sp, const struct nfs
         * server that doesn't support a grace period.
         */
        spin_lock(&sp->so_lock);
-       write_seqcount_begin(&sp->so_reclaim_seqcount);
+       raw_write_seqcount_begin(&sp->so_reclaim_seqcount);
 restart:
        list_for_each_entry(state, &sp->so_states, open_states) {
                if (!test_and_clear_bit(ops->state_flag_bit, &state->flags))
@@ -1519,13 +1519,13 @@ restart:
                spin_lock(&sp->so_lock);
                goto restart;
        }
-       write_seqcount_end(&sp->so_reclaim_seqcount);
+       raw_write_seqcount_end(&sp->so_reclaim_seqcount);
        spin_unlock(&sp->so_lock);
        return 0;
 out_err:
        nfs4_put_open_state(state);
        spin_lock(&sp->so_lock);
-       write_seqcount_end(&sp->so_reclaim_seqcount);
+       raw_write_seqcount_end(&sp->so_reclaim_seqcount);
        spin_unlock(&sp->so_lock);
        return status;
 }