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-rw-r--r--fs/jffs2/background.c140
1 files changed, 140 insertions, 0 deletions
diff --git a/fs/jffs2/background.c b/fs/jffs2/background.c
new file mode 100644
index 000000000000..1be6de27dd81
--- /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);
+}
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