patch-2.4.10 linux/fs/jffs2/background.c

• Lines: 177
• Date: Fri Sep 14 14:04:07 2001
• Orig file: v2.4.9/linux/fs/jffs2/background.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.9/linux/fs/jffs2/background.c linux/fs/jffs2/background.c
@@ -0,0 +1,176 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright (C) 2001 Red Hat, Inc.
+ *
+ * Created by David Woodhouse <dwmw2@cambridge.redhat.com>
+ *
+ * The original JFFS, from which the design for JFFS2 was derived,
+ * was designed and implemented by Axis Communications AB.
+ *
+ * The contents of this file are subject to the Red Hat eCos Public
+ * License Version 1.1 (the "Licence"); you may not use this file
+ * except in compliance with the Licence.  You may obtain a copy of
+ * the Licence at http://www.redhat.com/
+ *
+ * Software distributed under the Licence is distributed on an "AS IS"
+ * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.
+ * See the Licence for the specific language governing rights and
+ * limitations under the Licence.
+ *
+ * The Original Code is JFFS2 - Journalling Flash File System, version 2
+ *
+ * Alternatively, the contents of this file may be used under the
+ * terms of the GNU General Public License version 2 (the "GPL"), in
+ * which case the provisions of the GPL are applicable instead of the
+ * above.  If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the RHEPL, indicate your decision by
+ * deleting the provisions above and replace them with the notice and
+ * other provisions required by the GPL.  If you do not delete the
+ * provisions above, a recipient may use your version of this file
+ * under either the RHEPL or the GPL.
+ *
+ * $Id: background.c,v 1.10 2001/03/15 15:38:23 dwmw2 Exp $
+ *
+ */
+
+#define __KERNEL_SYSCALLS__
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/unistd.h>
+#include <linux/jffs2.h>
+#include <linux/mtd/mtd.h>
+#include <linux/interrupt.h>
+#include <linux/smp_lock.h>
+#include "nodelist.h"
+
+
+static int jffs2_garbage_collect_thread(void *);
+static int thread_should_wake(struct jffs2_sb_info *c);
+
+void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c)
+{
+	spin_lock_bh(&c->erase_completion_lock);
+        if (c->gc_task && thread_should_wake(c))
+                send_sig(SIGHUP, c->gc_task, 1);
+	spin_unlock_bh(&c->erase_completion_lock);
+}
+
+int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c)
+{
+	pid_t pid;
+	int ret = 0;
+	init_MUTEX_LOCKED(&c->gc_thread_sem);
+	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);
+		ret = pid;
+	} else {
+		/* Wait for it... */
+		D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid));
+		down(&c->gc_thread_sem);
+	}
+	up(&c->gc_thread_sem);
+ 
+	return ret;
+}
+
+void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
+{
+	spin_lock_bh(&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_bh(&c->erase_completion_lock);
+	down(&c->gc_thread_sem);
+	wait_for_completion(&c->gc_thread_exit);
+}
+
+static int jffs2_garbage_collect_thread(void *_c)
+{
+	struct jffs2_sb_info *c = _c;
+
+	daemonize();
+	current->tty = NULL;
+	c->gc_task = current;
+	up(&c->gc_thread_sem);
+
+        sprintf(current->comm, "jffs2_gcd_mtd%d", c->mtd->index);
+
+	/* FIXME in the 2.2 backport */
+	current->nice = 10;
+
+	for (;;) {
+		spin_lock_irq(&current->sigmask_lock);
+		siginitsetinv (&current->blocked, sigmask(SIGHUP) | sigmask(SIGKILL) | sigmask(SIGSTOP) | sigmask(SIGCONT));
+		recalc_sigpending(current);
+		spin_unlock_irq(&current->sigmask_lock);
+
+		if (!thread_should_wake(c)) {
+                        set_current_state (TASK_INTERRUPTIBLE);
+			D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n"));
+		}
+                
+                schedule(); /* Yes, we do this even if we want to go
+			       on immediately - we're a low priority 
+			       background task. */
+
+                /* Put_super will send a SIGKILL and then wait on the sem. 
+                 */
+                while (signal_pending(current)) {
+                        siginfo_t info;
+                        unsigned long signr;
+
+                        spin_lock_irq(&current->sigmask_lock);
+                        signr = dequeue_signal(&current->blocked, &info);
+                        spin_unlock_irq(&current->sigmask_lock);
+
+                        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"));
+				spin_lock_bh(&c->erase_completion_lock);
+                                c->gc_task = NULL;
+				spin_unlock_bh(&c->erase_completion_lock);
+				up(&c->gc_thread_sem);
+				complete_and_exit(&c->gc_thread_exit,0 );
+
+			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. */
+		spin_lock_irq(&current->sigmask_lock);
+		siginitsetinv (&current->blocked, sigmask(SIGKILL) | sigmask(SIGSTOP) | sigmask(SIGCONT));
+		recalc_sigpending(current);
+		spin_unlock_irq(&current->sigmask_lock);
+
+		D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n"));
+		jffs2_garbage_collect_pass(c);
+	}
+}
+
+static int thread_should_wake(struct jffs2_sb_info *c)
+{
+	D1(printk(KERN_DEBUG "thread_should_wake(): nr_free_blocks %d, nr_erasing_blocks %d, dirty_size 0x%x\n", 
+		  c->nr_free_blocks, c->nr_erasing_blocks, c->dirty_size));
+	if (c->nr_free_blocks + c->nr_erasing_blocks < JFFS2_RESERVED_BLOCKS_GCTRIGGER &&
+	    c->dirty_size > c->sector_size)
+		return 1;
+	else 
+		return 0;
+}