11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * JFFS2 -- Journalling Flash File System, Version 2. 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 2001-2003 Red Hat, Inc. 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Created by David Woodhouse <dwmw2@infradead.org> 71da177e4SLinus Torvalds * 81da177e4SLinus Torvalds * For licensing information, see the file 'LICENCE' in this directory. 91da177e4SLinus Torvalds * 10e2d48b1aSThomas Gleixner * $Id: background.c,v 1.54 2005/05/20 21:37:12 gleixner Exp $ 111da177e4SLinus Torvalds * 121da177e4SLinus Torvalds */ 131da177e4SLinus Torvalds 141da177e4SLinus Torvalds #include <linux/kernel.h> 151da177e4SLinus Torvalds #include <linux/jffs2.h> 161da177e4SLinus Torvalds #include <linux/mtd/mtd.h> 171da177e4SLinus Torvalds #include <linux/completion.h> 184e57b681STim Schmielau #include <linux/sched.h> 197dfb7103SNigel Cunningham #include <linux/freezer.h> 201da177e4SLinus Torvalds #include "nodelist.h" 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds 231da177e4SLinus Torvalds static int jffs2_garbage_collect_thread(void *); 241da177e4SLinus Torvalds 251da177e4SLinus Torvalds void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c) 261da177e4SLinus Torvalds { 271da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 281da177e4SLinus Torvalds if (c->gc_task && jffs2_thread_should_wake(c)) 291da177e4SLinus Torvalds send_sig(SIGHUP, c->gc_task, 1); 301da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 311da177e4SLinus Torvalds } 321da177e4SLinus Torvalds 331da177e4SLinus Torvalds /* This must only ever be called when no GC thread is currently running */ 341da177e4SLinus Torvalds int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c) 351da177e4SLinus Torvalds { 361da177e4SLinus Torvalds pid_t pid; 371da177e4SLinus Torvalds int ret = 0; 381da177e4SLinus Torvalds 394b4d1cc7SEric Sesterhenn BUG_ON(c->gc_task); 401da177e4SLinus Torvalds 41fff7afd7SThomas Gleixner init_completion(&c->gc_thread_start); 421da177e4SLinus Torvalds init_completion(&c->gc_thread_exit); 431da177e4SLinus Torvalds 441da177e4SLinus Torvalds pid = kernel_thread(jffs2_garbage_collect_thread, c, CLONE_FS|CLONE_FILES); 451da177e4SLinus Torvalds if (pid < 0) { 461da177e4SLinus Torvalds printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %d\n", -pid); 471da177e4SLinus Torvalds complete(&c->gc_thread_exit); 481da177e4SLinus Torvalds ret = pid; 491da177e4SLinus Torvalds } else { 501da177e4SLinus Torvalds /* Wait for it... */ 511da177e4SLinus Torvalds D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid)); 52fff7afd7SThomas Gleixner wait_for_completion(&c->gc_thread_start); 531da177e4SLinus Torvalds } 541da177e4SLinus Torvalds 551da177e4SLinus Torvalds return ret; 561da177e4SLinus Torvalds } 571da177e4SLinus Torvalds 581da177e4SLinus Torvalds void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c) 591da177e4SLinus Torvalds { 60e2d48b1aSThomas Gleixner int wait = 0; 611da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 621da177e4SLinus Torvalds if (c->gc_task) { 631da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid)); 641da177e4SLinus Torvalds send_sig(SIGKILL, c->gc_task, 1); 65e2d48b1aSThomas Gleixner wait = 1; 661da177e4SLinus Torvalds } 671da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 68e2d48b1aSThomas Gleixner if (wait) 691da177e4SLinus Torvalds wait_for_completion(&c->gc_thread_exit); 701da177e4SLinus Torvalds } 711da177e4SLinus Torvalds 721da177e4SLinus Torvalds static int jffs2_garbage_collect_thread(void *_c) 731da177e4SLinus Torvalds { 741da177e4SLinus Torvalds struct jffs2_sb_info *c = _c; 751da177e4SLinus Torvalds 761da177e4SLinus Torvalds daemonize("jffs2_gcd_mtd%d", c->mtd->index); 771da177e4SLinus Torvalds allow_signal(SIGKILL); 781da177e4SLinus Torvalds allow_signal(SIGSTOP); 791da177e4SLinus Torvalds allow_signal(SIGCONT); 801da177e4SLinus Torvalds 811da177e4SLinus Torvalds c->gc_task = current; 82fff7afd7SThomas Gleixner complete(&c->gc_thread_start); 831da177e4SLinus Torvalds 841da177e4SLinus Torvalds set_user_nice(current, 10); 851da177e4SLinus Torvalds 861da177e4SLinus Torvalds for (;;) { 871da177e4SLinus Torvalds allow_signal(SIGHUP); 881da177e4SLinus Torvalds 891da177e4SLinus Torvalds if (!jffs2_thread_should_wake(c)) { 901da177e4SLinus Torvalds set_current_state (TASK_INTERRUPTIBLE); 911da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n")); 921da177e4SLinus Torvalds /* Yes, there's a race here; we checked jffs2_thread_should_wake() 931da177e4SLinus Torvalds before setting current->state to TASK_INTERRUPTIBLE. But it doesn't 941da177e4SLinus Torvalds matter - We don't care if we miss a wakeup, because the GC thread 951da177e4SLinus Torvalds is only an optimisation anyway. */ 961da177e4SLinus Torvalds schedule(); 971da177e4SLinus Torvalds } 981da177e4SLinus Torvalds 9934f18a98SAndrew Morton if (try_to_freeze()) 1001da177e4SLinus Torvalds continue; 1011da177e4SLinus Torvalds 1021da177e4SLinus Torvalds cond_resched(); 1031da177e4SLinus Torvalds 1041da177e4SLinus Torvalds /* Put_super will send a SIGKILL and then wait on the sem. 1051da177e4SLinus Torvalds */ 1061da177e4SLinus Torvalds while (signal_pending(current)) { 1071da177e4SLinus Torvalds siginfo_t info; 1081da177e4SLinus Torvalds unsigned long signr; 1091da177e4SLinus Torvalds 1101da177e4SLinus Torvalds signr = dequeue_signal_lock(current, ¤t->blocked, &info); 1111da177e4SLinus Torvalds 1121da177e4SLinus Torvalds switch(signr) { 1131da177e4SLinus Torvalds case SIGSTOP: 1141da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n")); 1151da177e4SLinus Torvalds set_current_state(TASK_STOPPED); 1161da177e4SLinus Torvalds schedule(); 1171da177e4SLinus Torvalds break; 1181da177e4SLinus Torvalds 1191da177e4SLinus Torvalds case SIGKILL: 1201da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n")); 1211da177e4SLinus Torvalds goto die; 1221da177e4SLinus Torvalds 1231da177e4SLinus Torvalds case SIGHUP: 1241da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n")); 1251da177e4SLinus Torvalds break; 1261da177e4SLinus Torvalds default: 1271da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr)); 1281da177e4SLinus Torvalds } 1291da177e4SLinus Torvalds } 1301da177e4SLinus Torvalds /* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */ 1311da177e4SLinus Torvalds disallow_signal(SIGHUP); 1321da177e4SLinus Torvalds 1331da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n")); 1341da177e4SLinus Torvalds if (jffs2_garbage_collect_pass(c) == -ENOSPC) { 1351da177e4SLinus Torvalds printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n"); 1361da177e4SLinus Torvalds goto die; 1371da177e4SLinus Torvalds } 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds die: 1401da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 1411da177e4SLinus Torvalds c->gc_task = NULL; 1421da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 1431da177e4SLinus Torvalds complete_and_exit(&c->gc_thread_exit, 0); 1441da177e4SLinus Torvalds } 145