diff options
Diffstat (limited to 'fs/jffs2/background.c')
| -rw-r--r-- | fs/jffs2/background.c | 140 |
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, ¤t->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); +} |