[DLM] block dlm_recv in recovery transition

[linux-2.6-omap-h63xx.git] / fs / dlm / recoverd.c

diff --git a/fs/dlm/recoverd.c b/fs/dlm/recoverd.c
index 66575997861cad1da5e02e9528deaaf6240751b7..4b89e20eebe702f32a9214d2f377e1efc2768001 100644 (file)
--- a/fs/dlm/recoverd.c
+++ b/fs/dlm/recoverd.c
@@ -24,19 +24,28 @@
 
 
 /* If the start for which we're re-enabling locking (seq) has been superseded
-   by a newer stop (ls_recover_seq), we need to leave locking disabled. */
+   by a newer stop (ls_recover_seq), we need to leave locking disabled.
+
+   We suspend dlm_recv threads here to avoid the race where dlm_recv a) sees
+   locking stopped and b) adds a message to the requestqueue, but dlm_recoverd
+   enables locking and clears the requestqueue between a and b. */
 
 static int enable_locking(struct dlm_ls *ls, uint64_t seq)
 {
        int error = -EINTR;
 
+       down_write(&ls->ls_recv_active);
+
        spin_lock(&ls->ls_recover_lock);
        if (ls->ls_recover_seq == seq) {
                set_bit(LSFL_RUNNING, &ls->ls_flags);
+               /* unblocks processes waiting to enter the dlm */
                up_write(&ls->ls_in_recovery);
                error = 0;
        }
        spin_unlock(&ls->ls_recover_lock);
+
+       up_write(&ls->ls_recv_active);
        return error;
 }