1 files changed, 140 insertions, 0 deletions
diff --git a/fs/jffs2/background.c b/fs/jffs2/background.c
new file mode 100644
index 0000000..1be6de2
--- /dev/null
+++ b/fs/jffs2/background.c
@@ -0,0 +1,140 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright (C) 2001-2003 Red Hat, Inc.
+ *
+ * Created by David Woodhouse <dwmw2@infradead.org>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ * $Id: background.c,v 1.50 2004/11/16 20:36:10 dwmw2 Exp $
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/jffs2.h>
+#include <linux/mtd/mtd.h>
+#include <linux/completion.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;
+
+	if (c->gc_task)
+		BUG();
+
+	init_MUTEX_LOCKED(&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));
+		down(&c->gc_thread_start);
+	}
+ 
+	return ret;
+}
+
+void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
+{
+	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);
+	}
+	spin_unlock(&c->erase_completion_lock);
+	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;
+	up(&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(0))
+			continue;
+
+		cond_resched();
+
+		/* 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);
+}