linux/fs/jffs2/background.c
David Woodhouse c00c310eac [JFFS2] Tidy up licensing/copyright boilerplate.
In particular, remove the bit in the LICENCE file about contacting
Red Hat for alternative arrangements. Their errant IS department broke
that arrangement a long time ago -- the policy of collecting copyright
assignments from contributors came to an end when the plug was pulled on
the servers hosting the project, without notice or reason.

We do still dual-license it for use with eCos, with the GPL+exception
licence approved by the FSF as being GPL-compatible. It's just that nobody
has the right to license it differently.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2007-04-25 14:16:47 +01:00

149 lines
4.0 KiB
C

/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright © 2001-2007 Red Hat, Inc.
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
*/
#include <linux/kernel.h>
#include <linux/jffs2.h>
#include <linux/mtd/mtd.h>
#include <linux/completion.h>
#include <linux/sched.h>
#include <linux/freezer.h>
#include "nodelist.h"
static int jffs2_garbage_collect_thread(void *);
void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c)
{
spin_lock(&c->erase_completion_lock);
if (c->gc_task && jffs2_thread_should_wake(c))
send_sig(SIGHUP, c->gc_task, 1);
spin_unlock(&c->erase_completion_lock);
}
/* This must only ever be called when no GC thread is currently running */
int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c)
{
pid_t pid;
int ret = 0;
BUG_ON(c->gc_task);
init_completion(&c->gc_thread_start);
init_completion(&c->gc_thread_exit);
pid = kernel_thread(jffs2_garbage_collect_thread, c, CLONE_FS|CLONE_FILES);
if (pid < 0) {
printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %d\n", -pid);
complete(&c->gc_thread_exit);
ret = pid;
} else {
/* Wait for it... */
D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid));
wait_for_completion(&c->gc_thread_start);
}
return ret;
}
void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
{
int wait = 0;
spin_lock(&c->erase_completion_lock);
if (c->gc_task) {
D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid));
send_sig(SIGKILL, c->gc_task, 1);
wait = 1;
}
spin_unlock(&c->erase_completion_lock);
if (wait)
wait_for_completion(&c->gc_thread_exit);
}
static int jffs2_garbage_collect_thread(void *_c)
{
struct jffs2_sb_info *c = _c;
daemonize("jffs2_gcd_mtd%d", c->mtd->index);
allow_signal(SIGKILL);
allow_signal(SIGSTOP);
allow_signal(SIGCONT);
c->gc_task = current;
complete(&c->gc_thread_start);
set_user_nice(current, 10);
for (;;) {
allow_signal(SIGHUP);
if (!jffs2_thread_should_wake(c)) {
set_current_state (TASK_INTERRUPTIBLE);
D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n"));
/* Yes, there's a race here; we checked jffs2_thread_should_wake()
before setting current->state to TASK_INTERRUPTIBLE. But it doesn't
matter - We don't care if we miss a wakeup, because the GC thread
is only an optimisation anyway. */
schedule();
}
if (try_to_freeze())
continue;
/* This thread is purely an optimisation. But if it runs when
other things could be running, it actually makes things a
lot worse. Use yield() and put it at the back of the runqueue
every time. Especially during boot, pulling an inode in
with read_inode() is much preferable to having the GC thread
get there first. */
yield();
/* Put_super will send a SIGKILL and then wait on the sem.
*/
while (signal_pending(current)) {
siginfo_t info;
unsigned long signr;
signr = dequeue_signal_lock(current, &current->blocked, &info);
switch(signr) {
case SIGSTOP:
D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n"));
set_current_state(TASK_STOPPED);
schedule();
break;
case SIGKILL:
D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n"));
goto die;
case SIGHUP:
D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n"));
break;
default:
D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr));
}
}
/* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */
disallow_signal(SIGHUP);
D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n"));
if (jffs2_garbage_collect_pass(c) == -ENOSPC) {
printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n");
goto die;
}
}
die:
spin_lock(&c->erase_completion_lock);
c->gc_task = NULL;
spin_unlock(&c->erase_completion_lock);
complete_and_exit(&c->gc_thread_exit, 0);
}