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/* Support for periodic syncing
Copyright (C) 1995 Free Software Foundation, Inc.
Written by Miles Bader <miles@gnu.ai.mit.edu>
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 <errno.h>
#include <cthreads.h>
#include <unistd.h>
#include <hurd/fsys.h>
#include "priv.h"
/* The thread that's doing the syncing. */
cthread_t periodic_sync_thread = 0;
/* A lock to lock before changing any of the above. */
spin_lock_t periodic_sync_lock = SPIN_LOCK_INITIALIZER;
/* The filesystem control port to which we send our sync requests. */
mach_port_t control_port;
/* ---------------------------------------------------------------- */
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 (control_port == MACH_PORT_NULL)
{
control_port =
ports_get_right (ports_allocate_port
(sizeof (struct port_info), PT_CTL));
err =
mach_port_insert_right (mach_task_self (),
control_port, control_port,
MACH_MSG_TYPE_MAKE_SEND);
}
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;
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;
fsys_syncfs (control_port, 0, 0);
/* Wait until next time. */
sleep (interval);
}
}
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