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 * 10fff7afd7SThomas Gleixner * $Id: background.c,v 1.52 2005/05/19 16:18:08 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> 181da177e4SLinus Torvalds #include "nodelist.h" 191da177e4SLinus Torvalds 201da177e4SLinus Torvalds 211da177e4SLinus Torvalds static int jffs2_garbage_collect_thread(void *); 221da177e4SLinus Torvalds 231da177e4SLinus Torvalds void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c) 241da177e4SLinus Torvalds { 251da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 261da177e4SLinus Torvalds if (c->gc_task && jffs2_thread_should_wake(c)) 271da177e4SLinus Torvalds send_sig(SIGHUP, c->gc_task, 1); 281da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 291da177e4SLinus Torvalds } 301da177e4SLinus Torvalds 311da177e4SLinus Torvalds /* This must only ever be called when no GC thread is currently running */ 321da177e4SLinus Torvalds int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c) 331da177e4SLinus Torvalds { 341da177e4SLinus Torvalds pid_t pid; 351da177e4SLinus Torvalds int ret = 0; 361da177e4SLinus Torvalds 371da177e4SLinus Torvalds if (c->gc_task) 381da177e4SLinus Torvalds BUG(); 391da177e4SLinus Torvalds 40fff7afd7SThomas Gleixner init_completion(&c->gc_thread_start); 411da177e4SLinus Torvalds init_completion(&c->gc_thread_exit); 421da177e4SLinus Torvalds 431da177e4SLinus Torvalds pid = kernel_thread(jffs2_garbage_collect_thread, c, CLONE_FS|CLONE_FILES); 441da177e4SLinus Torvalds if (pid < 0) { 451da177e4SLinus Torvalds printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %d\n", -pid); 461da177e4SLinus Torvalds complete(&c->gc_thread_exit); 471da177e4SLinus Torvalds ret = pid; 481da177e4SLinus Torvalds } else { 491da177e4SLinus Torvalds /* Wait for it... */ 501da177e4SLinus Torvalds D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid)); 51fff7afd7SThomas Gleixner wait_for_completion(&c->gc_thread_start); 521da177e4SLinus Torvalds } 531da177e4SLinus Torvalds 541da177e4SLinus Torvalds return ret; 551da177e4SLinus Torvalds } 561da177e4SLinus Torvalds 571da177e4SLinus Torvalds void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c) 581da177e4SLinus Torvalds { 591da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 601da177e4SLinus Torvalds if (c->gc_task) { 611da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid)); 621da177e4SLinus Torvalds send_sig(SIGKILL, c->gc_task, 1); 631da177e4SLinus Torvalds } 641da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 651da177e4SLinus Torvalds wait_for_completion(&c->gc_thread_exit); 661da177e4SLinus Torvalds } 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds static int jffs2_garbage_collect_thread(void *_c) 691da177e4SLinus Torvalds { 701da177e4SLinus Torvalds struct jffs2_sb_info *c = _c; 711da177e4SLinus Torvalds 721da177e4SLinus Torvalds daemonize("jffs2_gcd_mtd%d", c->mtd->index); 731da177e4SLinus Torvalds allow_signal(SIGKILL); 741da177e4SLinus Torvalds allow_signal(SIGSTOP); 751da177e4SLinus Torvalds allow_signal(SIGCONT); 761da177e4SLinus Torvalds 771da177e4SLinus Torvalds c->gc_task = current; 78fff7afd7SThomas Gleixner complete(&c->gc_thread_start); 791da177e4SLinus Torvalds 801da177e4SLinus Torvalds set_user_nice(current, 10); 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds for (;;) { 831da177e4SLinus Torvalds allow_signal(SIGHUP); 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds if (!jffs2_thread_should_wake(c)) { 861da177e4SLinus Torvalds set_current_state (TASK_INTERRUPTIBLE); 871da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n")); 881da177e4SLinus Torvalds /* Yes, there's a race here; we checked jffs2_thread_should_wake() 891da177e4SLinus Torvalds before setting current->state to TASK_INTERRUPTIBLE. But it doesn't 901da177e4SLinus Torvalds matter - We don't care if we miss a wakeup, because the GC thread 911da177e4SLinus Torvalds is only an optimisation anyway. */ 921da177e4SLinus Torvalds schedule(); 931da177e4SLinus Torvalds } 941da177e4SLinus Torvalds 951da177e4SLinus Torvalds if (try_to_freeze(0)) 961da177e4SLinus Torvalds continue; 971da177e4SLinus Torvalds 981da177e4SLinus Torvalds cond_resched(); 991da177e4SLinus Torvalds 1001da177e4SLinus Torvalds /* Put_super will send a SIGKILL and then wait on the sem. 1011da177e4SLinus Torvalds */ 1021da177e4SLinus Torvalds while (signal_pending(current)) { 1031da177e4SLinus Torvalds siginfo_t info; 1041da177e4SLinus Torvalds unsigned long signr; 1051da177e4SLinus Torvalds 1061da177e4SLinus Torvalds signr = dequeue_signal_lock(current, ¤t->blocked, &info); 1071da177e4SLinus Torvalds 1081da177e4SLinus Torvalds switch(signr) { 1091da177e4SLinus Torvalds case SIGSTOP: 1101da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n")); 1111da177e4SLinus Torvalds set_current_state(TASK_STOPPED); 1121da177e4SLinus Torvalds schedule(); 1131da177e4SLinus Torvalds break; 1141da177e4SLinus Torvalds 1151da177e4SLinus Torvalds case SIGKILL: 1161da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n")); 1171da177e4SLinus Torvalds goto die; 1181da177e4SLinus Torvalds 1191da177e4SLinus Torvalds case SIGHUP: 1201da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n")); 1211da177e4SLinus Torvalds break; 1221da177e4SLinus Torvalds default: 1231da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr)); 1241da177e4SLinus Torvalds } 1251da177e4SLinus Torvalds } 1261da177e4SLinus Torvalds /* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */ 1271da177e4SLinus Torvalds disallow_signal(SIGHUP); 1281da177e4SLinus Torvalds 1291da177e4SLinus Torvalds D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n")); 1301da177e4SLinus Torvalds if (jffs2_garbage_collect_pass(c) == -ENOSPC) { 1311da177e4SLinus Torvalds printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n"); 1321da177e4SLinus Torvalds goto die; 1331da177e4SLinus Torvalds } 1341da177e4SLinus Torvalds } 1351da177e4SLinus Torvalds die: 1361da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 1371da177e4SLinus Torvalds c->gc_task = NULL; 1381da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 1391da177e4SLinus Torvalds complete_and_exit(&c->gc_thread_exit, 0); 1401da177e4SLinus Torvalds } 141