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)) { 45da320f05SJoe Perches pr_warn("fork failed for JFFS2 garbage collect thread: %ld\n", 46da320f05SJoe Perches -PTR_ERR(tsk)); 471da177e4SLinus Torvalds complete(&c->gc_thread_exit); 4891e0955bSGerard Lledo ret = PTR_ERR(tsk); 491da177e4SLinus Torvalds } else { 501da177e4SLinus Torvalds /* Wait for it... */ 519c261b33SJoe Perches jffs2_dbg(1, "JFFS2: Garbage collect thread is pid %d\n", 529c261b33SJoe Perches tsk->pid); 53fff7afd7SThomas Gleixner wait_for_completion(&c->gc_thread_start); 5491e0955bSGerard Lledo ret = tsk->pid; 551da177e4SLinus Torvalds } 561da177e4SLinus Torvalds 571da177e4SLinus Torvalds return ret; 581da177e4SLinus Torvalds } 591da177e4SLinus Torvalds 601da177e4SLinus Torvalds void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c) 611da177e4SLinus Torvalds { 62e2d48b1aSThomas Gleixner int wait = 0; 631da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 641da177e4SLinus Torvalds if (c->gc_task) { 659c261b33SJoe Perches jffs2_dbg(1, "jffs2: Killing GC task %d\n", c->gc_task->pid); 661da177e4SLinus Torvalds send_sig(SIGKILL, c->gc_task, 1); 67e2d48b1aSThomas Gleixner wait = 1; 681da177e4SLinus Torvalds } 691da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 70e2d48b1aSThomas Gleixner if (wait) 711da177e4SLinus Torvalds wait_for_completion(&c->gc_thread_exit); 721da177e4SLinus Torvalds } 731da177e4SLinus Torvalds 741da177e4SLinus Torvalds static int jffs2_garbage_collect_thread(void *_c) 751da177e4SLinus Torvalds { 761da177e4SLinus Torvalds struct jffs2_sb_info *c = _c; 771da177e4SLinus Torvalds 781da177e4SLinus Torvalds allow_signal(SIGKILL); 791da177e4SLinus Torvalds allow_signal(SIGSTOP); 801da177e4SLinus Torvalds allow_signal(SIGCONT); 811da177e4SLinus Torvalds 821da177e4SLinus Torvalds c->gc_task = current; 83fff7afd7SThomas Gleixner complete(&c->gc_thread_start); 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds set_user_nice(current, 10); 861da177e4SLinus Torvalds 8783144186SRafael J. Wysocki set_freezable(); 881da177e4SLinus Torvalds for (;;) { 891da177e4SLinus Torvalds allow_signal(SIGHUP); 90e716dd36SDavid Woodhouse again: 91b27cf88eSDavid Woodhouse spin_lock(&c->erase_completion_lock); 921da177e4SLinus Torvalds if (!jffs2_thread_should_wake(c)) { 931da177e4SLinus Torvalds set_current_state (TASK_INTERRUPTIBLE); 94b27cf88eSDavid Woodhouse spin_unlock(&c->erase_completion_lock); 959c261b33SJoe Perches jffs2_dbg(1, "%s(): sleeping...\n", __func__); 961da177e4SLinus Torvalds schedule(); 97b27cf88eSDavid Woodhouse } else 98b27cf88eSDavid Woodhouse spin_unlock(&c->erase_completion_lock); 99b27cf88eSDavid Woodhouse 1001da177e4SLinus Torvalds 101efab0b5dSAndres Salomon /* Problem - immediately after bootup, the GCD spends a lot 102efab0b5dSAndres Salomon * of time in places like jffs2_kill_fragtree(); so much so 103efab0b5dSAndres Salomon * that userspace processes (like gdm and X) are starved 104efab0b5dSAndres Salomon * despite plenty of cond_resched()s and renicing. Yield() 105efab0b5dSAndres Salomon * doesn't help, either (presumably because userspace and GCD 106efab0b5dSAndres Salomon * are generally competing for a higher latency resource - 107efab0b5dSAndres Salomon * disk). 108efab0b5dSAndres Salomon * This forces the GCD to slow the hell down. Pulling an 109efab0b5dSAndres Salomon * inode in with read_inode() is much preferable to having 110efab0b5dSAndres Salomon * the GC thread get there first. */ 111efab0b5dSAndres Salomon schedule_timeout_interruptible(msecs_to_jiffies(50)); 1121da177e4SLinus Torvalds 11391e0955bSGerard Lledo if (kthread_should_stop()) { 1149c261b33SJoe Perches jffs2_dbg(1, "%s(): kthread_stop() called\n", __func__); 11591e0955bSGerard Lledo goto die; 11691e0955bSGerard Lledo } 11791e0955bSGerard Lledo 1181da177e4SLinus Torvalds /* Put_super will send a SIGKILL and then wait on the sem. 1191da177e4SLinus Torvalds */ 120e136e769SRafael J. Wysocki while (signal_pending(current) || freezing(current)) { 1211da177e4SLinus Torvalds siginfo_t info; 1221da177e4SLinus Torvalds unsigned long signr; 1231da177e4SLinus Torvalds 124e716dd36SDavid Woodhouse if (try_to_freeze()) 125e716dd36SDavid Woodhouse goto again; 126e716dd36SDavid Woodhouse 1271da177e4SLinus Torvalds signr = dequeue_signal_lock(current, ¤t->blocked, &info); 1281da177e4SLinus Torvalds 1291da177e4SLinus Torvalds switch(signr) { 1301da177e4SLinus Torvalds case SIGSTOP: 1319c261b33SJoe Perches jffs2_dbg(1, "%s(): SIGSTOP received\n", 1329c261b33SJoe Perches __func__); 1331da177e4SLinus Torvalds set_current_state(TASK_STOPPED); 1341da177e4SLinus Torvalds schedule(); 1351da177e4SLinus Torvalds break; 1361da177e4SLinus Torvalds 1371da177e4SLinus Torvalds case SIGKILL: 1389c261b33SJoe Perches jffs2_dbg(1, "%s(): SIGKILL received\n", 1399c261b33SJoe Perches __func__); 1401da177e4SLinus Torvalds goto die; 1411da177e4SLinus Torvalds 1421da177e4SLinus Torvalds case SIGHUP: 1439c261b33SJoe Perches jffs2_dbg(1, "%s(): SIGHUP received\n", 1449c261b33SJoe Perches __func__); 1451da177e4SLinus Torvalds break; 1461da177e4SLinus Torvalds default: 1479c261b33SJoe Perches jffs2_dbg(1, "%s(): signal %ld received\n", 1489c261b33SJoe Perches __func__, signr); 1491da177e4SLinus Torvalds } 1501da177e4SLinus Torvalds } 1511da177e4SLinus Torvalds /* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */ 1521da177e4SLinus Torvalds disallow_signal(SIGHUP); 1531da177e4SLinus Torvalds 1549c261b33SJoe Perches jffs2_dbg(1, "%s(): pass\n", __func__); 1551da177e4SLinus Torvalds if (jffs2_garbage_collect_pass(c) == -ENOSPC) { 156da320f05SJoe Perches pr_notice("No space for garbage collection. Aborting GC thread\n"); 1571da177e4SLinus Torvalds goto die; 1581da177e4SLinus Torvalds } 1591da177e4SLinus Torvalds } 1601da177e4SLinus Torvalds die: 1611da177e4SLinus Torvalds spin_lock(&c->erase_completion_lock); 1621da177e4SLinus Torvalds c->gc_task = NULL; 1631da177e4SLinus Torvalds spin_unlock(&c->erase_completion_lock); 1641da177e4SLinus Torvalds complete_and_exit(&c->gc_thread_exit, 0); 1651da177e4SLinus Torvalds } 166