11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * JFFS2 -- Journalling Flash File System, Version 2. 31da177e4SLinus Torvalds * 4c00c310eSDavid Woodhouse * Copyright © 2001-2007 Red Hat, Inc. 56088c058SDavid Woodhouse * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org> 61da177e4SLinus Torvalds * 71da177e4SLinus Torvalds * Created by David Woodhouse <dwmw2@infradead.org> 81da177e4SLinus Torvalds * 91da177e4SLinus Torvalds * For licensing information, see the file 'LICENCE' in this directory. 101da177e4SLinus Torvalds * 111da177e4SLinus Torvalds */ 121da177e4SLinus Torvalds 131da177e4SLinus Torvalds #include <linux/kernel.h> 141da177e4SLinus Torvalds #include <linux/jffs2.h> 151da177e4SLinus Torvalds #include <linux/mtd/mtd.h> 161da177e4SLinus Torvalds #include <linux/completion.h> 174e57b681STim Schmielau #include <linux/sched.h> 187dfb7103SNigel Cunningham #include <linux/freezer.h> 1991e0955bSGerard Lledo #include <linux/kthread.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 { 27acb64a43SDavid Woodhouse assert_spin_locked(&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 } 311da177e4SLinus Torvalds 321da177e4SLinus Torvalds /* This must only ever be called when no GC thread is currently running */ 331da177e4SLinus Torvalds int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c) 341da177e4SLinus Torvalds { 3591e0955bSGerard Lledo struct task_struct *tsk; 361da177e4SLinus Torvalds int ret = 0; 371da177e4SLinus Torvalds 384b4d1cc7SEric Sesterhenn BUG_ON(c->gc_task); 391da177e4SLinus Torvalds 40fff7afd7SThomas Gleixner init_completion(&c->gc_thread_start); 411da177e4SLinus Torvalds init_completion(&c->gc_thread_exit); 421da177e4SLinus Torvalds 4391e0955bSGerard Lledo tsk = kthread_run(jffs2_garbage_collect_thread, c, "jffs2_gcd_mtd%d", c->mtd->index); 4491e0955bSGerard Lledo if (IS_ERR(tsk)) { 4591e0955bSGerard Lledo printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %ld\n", -PTR_ERR(tsk)); 461da177e4SLinus Torvalds complete(&c->gc_thread_exit); 4791e0955bSGerard Lledo ret = PTR_ERR(tsk); 481da177e4SLinus Torvalds } else { 491da177e4SLinus Torvalds /* Wait for it... */ 509c261b33SJoe Perches jffs2_dbg(1, "JFFS2: Garbage collect thread is pid %d\n", 519c261b33SJoe Perches tsk->pid); 52fff7afd7SThomas Gleixner wait_for_completion(&c->gc_thread_start); 5391e0955bSGerard Lledo ret = tsk->pid; 541da177e4SLinus Torvalds } 551da177e4SLinus Torvalds 561da177e4SLinus Torvalds return ret; 571da177e4SLinus Torvalds } 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c) 601da177e4SLinus Torvalds { 61e2d48b1aSThomas Gleixner int wait = 0; 621da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 631da177e4SLinus Torvalds if (c->gc_task) { 649c261b33SJoe Perches jffs2_dbg(1, "jffs2: Killing GC task %d\n", c->gc_task->pid); 651da177e4SLinus Torvalds send_sig(SIGKILL, c->gc_task, 1); 66e2d48b1aSThomas Gleixner wait = 1; 671da177e4SLinus Torvalds } 681da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 69e2d48b1aSThomas Gleixner if (wait) 701da177e4SLinus Torvalds wait_for_completion(&c->gc_thread_exit); 711da177e4SLinus Torvalds } 721da177e4SLinus Torvalds 731da177e4SLinus Torvalds static int jffs2_garbage_collect_thread(void *_c) 741da177e4SLinus Torvalds { 751da177e4SLinus Torvalds struct jffs2_sb_info *c = _c; 761da177e4SLinus Torvalds 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 8683144186SRafael J. Wysocki set_freezable(); 871da177e4SLinus Torvalds for (;;) { 881da177e4SLinus Torvalds allow_signal(SIGHUP); 89e716dd36SDavid Woodhouse again: 90b27cf88eSDavid Woodhouse spin_lock(&c->erase_completion_lock); 911da177e4SLinus Torvalds if (!jffs2_thread_should_wake(c)) { 921da177e4SLinus Torvalds set_current_state (TASK_INTERRUPTIBLE); 93b27cf88eSDavid Woodhouse spin_unlock(&c->erase_completion_lock); 949c261b33SJoe Perches jffs2_dbg(1, "%s(): sleeping...\n", __func__); 951da177e4SLinus Torvalds schedule(); 96b27cf88eSDavid Woodhouse } else 97b27cf88eSDavid Woodhouse spin_unlock(&c->erase_completion_lock); 98b27cf88eSDavid Woodhouse 991da177e4SLinus Torvalds 100efab0b5dSAndres Salomon /* Problem - immediately after bootup, the GCD spends a lot 101efab0b5dSAndres Salomon * of time in places like jffs2_kill_fragtree(); so much so 102efab0b5dSAndres Salomon * that userspace processes (like gdm and X) are starved 103efab0b5dSAndres Salomon * despite plenty of cond_resched()s and renicing. Yield() 104efab0b5dSAndres Salomon * doesn't help, either (presumably because userspace and GCD 105efab0b5dSAndres Salomon * are generally competing for a higher latency resource - 106efab0b5dSAndres Salomon * disk). 107efab0b5dSAndres Salomon * This forces the GCD to slow the hell down. Pulling an 108efab0b5dSAndres Salomon * inode in with read_inode() is much preferable to having 109efab0b5dSAndres Salomon * the GC thread get there first. */ 110efab0b5dSAndres Salomon schedule_timeout_interruptible(msecs_to_jiffies(50)); 1111da177e4SLinus Torvalds 11291e0955bSGerard Lledo if (kthread_should_stop()) { 1139c261b33SJoe Perches jffs2_dbg(1, "%s(): kthread_stop() called\n", __func__); 11491e0955bSGerard Lledo goto die; 11591e0955bSGerard Lledo } 11691e0955bSGerard Lledo 1171da177e4SLinus Torvalds /* Put_super will send a SIGKILL and then wait on the sem. 1181da177e4SLinus Torvalds */ 119e136e769SRafael J. Wysocki while (signal_pending(current) || freezing(current)) { 1201da177e4SLinus Torvalds siginfo_t info; 1211da177e4SLinus Torvalds unsigned long signr; 1221da177e4SLinus Torvalds 123e716dd36SDavid Woodhouse if (try_to_freeze()) 124e716dd36SDavid Woodhouse goto again; 125e716dd36SDavid Woodhouse 1261da177e4SLinus Torvalds signr = dequeue_signal_lock(current, ¤t->blocked, &info); 1271da177e4SLinus Torvalds 1281da177e4SLinus Torvalds switch(signr) { 1291da177e4SLinus Torvalds case SIGSTOP: 1309c261b33SJoe Perches jffs2_dbg(1, "%s(): SIGSTOP received\n", 1319c261b33SJoe Perches __func__); 1321da177e4SLinus Torvalds set_current_state(TASK_STOPPED); 1331da177e4SLinus Torvalds schedule(); 1341da177e4SLinus Torvalds break; 1351da177e4SLinus Torvalds 1361da177e4SLinus Torvalds case SIGKILL: 1379c261b33SJoe Perches jffs2_dbg(1, "%s(): SIGKILL received\n", 1389c261b33SJoe Perches __func__); 1391da177e4SLinus Torvalds goto die; 1401da177e4SLinus Torvalds 1411da177e4SLinus Torvalds case SIGHUP: 1429c261b33SJoe Perches jffs2_dbg(1, "%s(): SIGHUP received\n", 1439c261b33SJoe Perches __func__); 1441da177e4SLinus Torvalds break; 1451da177e4SLinus Torvalds default: 1469c261b33SJoe Perches jffs2_dbg(1, "%s(): signal %ld received\n", 1479c261b33SJoe Perches __func__, signr); 1481da177e4SLinus Torvalds } 1491da177e4SLinus Torvalds } 1501da177e4SLinus Torvalds /* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */ 1511da177e4SLinus Torvalds disallow_signal(SIGHUP); 1521da177e4SLinus Torvalds 1539c261b33SJoe Perches jffs2_dbg(1, "%s(): pass\n", __func__); 1541da177e4SLinus Torvalds if (jffs2_garbage_collect_pass(c) == -ENOSPC) { 1551da177e4SLinus Torvalds printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n"); 1561da177e4SLinus Torvalds goto die; 1571da177e4SLinus Torvalds } 1581da177e4SLinus Torvalds } 1591da177e4SLinus Torvalds die: 1601da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 1611da177e4SLinus Torvalds c->gc_task = NULL; 1621da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 1631da177e4SLinus Torvalds complete_and_exit(&c->gc_thread_exit, 0); 1641da177e4SLinus Torvalds } 165