145 lines
3.7 KiB
C
145 lines
3.7 KiB
C
/*
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* JFFS2 -- Journalling Flash File System, Version 2.
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*
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* Copyright (C) 2001-2003 Red Hat, Inc.
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*
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* Created by David Woodhouse <dwmw2@infradead.org>
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*
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* For licensing information, see the file 'LICENCE' in this directory.
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*
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* $Id: background.c,v 1.54 2005/05/20 21:37:12 gleixner Exp $
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*
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*/
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#include <linux/kernel.h>
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#include <linux/jffs2.h>
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#include <linux/mtd/mtd.h>
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#include <linux/completion.h>
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#include <linux/sched.h>
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#include "nodelist.h"
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static int jffs2_garbage_collect_thread(void *);
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void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c)
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{
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spin_lock(&c->erase_completion_lock);
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if (c->gc_task && jffs2_thread_should_wake(c))
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send_sig(SIGHUP, c->gc_task, 1);
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spin_unlock(&c->erase_completion_lock);
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}
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/* This must only ever be called when no GC thread is currently running */
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int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c)
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{
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pid_t pid;
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int ret = 0;
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if (c->gc_task)
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BUG();
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init_completion(&c->gc_thread_start);
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init_completion(&c->gc_thread_exit);
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pid = kernel_thread(jffs2_garbage_collect_thread, c, CLONE_FS|CLONE_FILES);
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if (pid < 0) {
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printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %d\n", -pid);
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complete(&c->gc_thread_exit);
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ret = pid;
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} else {
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/* Wait for it... */
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D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid));
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wait_for_completion(&c->gc_thread_start);
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}
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return ret;
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}
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void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
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{
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int wait = 0;
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spin_lock(&c->erase_completion_lock);
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if (c->gc_task) {
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D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid));
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send_sig(SIGKILL, c->gc_task, 1);
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wait = 1;
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}
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spin_unlock(&c->erase_completion_lock);
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if (wait)
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wait_for_completion(&c->gc_thread_exit);
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}
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static int jffs2_garbage_collect_thread(void *_c)
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{
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struct jffs2_sb_info *c = _c;
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daemonize("jffs2_gcd_mtd%d", c->mtd->index);
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allow_signal(SIGKILL);
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allow_signal(SIGSTOP);
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allow_signal(SIGCONT);
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c->gc_task = current;
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complete(&c->gc_thread_start);
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set_user_nice(current, 10);
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for (;;) {
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allow_signal(SIGHUP);
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if (!jffs2_thread_should_wake(c)) {
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set_current_state (TASK_INTERRUPTIBLE);
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D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n"));
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/* Yes, there's a race here; we checked jffs2_thread_should_wake()
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before setting current->state to TASK_INTERRUPTIBLE. But it doesn't
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matter - We don't care if we miss a wakeup, because the GC thread
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is only an optimisation anyway. */
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schedule();
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}
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if (try_to_freeze())
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continue;
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cond_resched();
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/* Put_super will send a SIGKILL and then wait on the sem.
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*/
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while (signal_pending(current)) {
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siginfo_t info;
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unsigned long signr;
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signr = dequeue_signal_lock(current, ¤t->blocked, &info);
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switch(signr) {
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case SIGSTOP:
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D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n"));
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set_current_state(TASK_STOPPED);
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schedule();
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break;
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case SIGKILL:
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D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n"));
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goto die;
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case SIGHUP:
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D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n"));
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break;
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default:
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D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr));
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}
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}
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/* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */
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disallow_signal(SIGHUP);
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D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n"));
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if (jffs2_garbage_collect_pass(c) == -ENOSPC) {
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printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n");
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goto die;
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}
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}
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die:
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spin_lock(&c->erase_completion_lock);
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c->gc_task = NULL;
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spin_unlock(&c->erase_completion_lock);
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complete_and_exit(&c->gc_thread_exit, 0);
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}
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