/* Support for periodic syncing Copyright (C) 1995 Free Software Foundation, Inc. Written by Miles Bader This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #include #include #include "priv.h" /* The thread that's doing the syncing. */ static cthread_t periodic_sync_thread = 0; /* A lock to lock before changing any of the above. */ static spin_lock_t periodic_sync_lock = SPIN_LOCK_INITIALIZER; static struct port_info *pi = 0; static void periodic_sync (); /* Establish a thread to sync the filesystem every INTERVAL seconds, or never, if INTERVAL is zero. If an error occurs creating the thread, it is returned, otherwise 0. Subsequent calls will create a new thread and (eventually) get rid of the old one; the old thread won't do any more syncs, regardless. */ error_t diskfs_set_sync_interval (int interval) { error_t err = 0; spin_lock (&periodic_sync_lock); if (!pi) pi = ports_allocate_port (diskfs_port_bucket, sizeof (struct port_info), diskfs_control_class); if (!err) /* Here we just set the new thread; any existing thread will notice when it wakes up and go away silently. */ if (interval == 0) periodic_sync_thread = 0; else { periodic_sync_thread = cthread_fork ((cthread_fn_t)periodic_sync, (any_t)interval); if (periodic_sync_thread) cthread_detach (periodic_sync_thread); else err = ED; } spin_unlock (&periodic_sync_lock); return 0; } /* ---------------------------------------------------------------- */ /* Sync the filesystem (pointed to by the variable CONTROL_PORT above) every INTERVAL seconds, as long as it's in the thread pointed to by the global variable PERIODIC_SYNC_THREAD. */ static void periodic_sync (int interval) { for (;;) { cthread_t thread; struct rpc_info link; spin_lock (&periodic_sync_lock); thread = periodic_sync_thread; spin_unlock (&periodic_sync_lock); if (thread != cthread_self ()) /* We've been superseded as the sync thread... Just die silently. */ return; ports_begin_rpc (pi, &link); diskfs_sync_everything (0); diskfs_set_hypermetadata (0, 0); ports_end_rpc (pi, &link); /* Wait until next time. */ sleep (interval); } }