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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
David Woodhousec00c3102007-04-25 14:16:47 +01004 * Copyright © 2001-2007 Red Hat, Inc.
David Woodhouse6088c052010-08-08 14:15:22 +01005 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
7 * Created by David Woodhouse <dwmw2@infradead.org>
8 *
9 * For licensing information, see the file 'LICENCE' in this directory.
10 *
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 */
12
13#include <linux/kernel.h>
14#include <linux/jffs2.h>
15#include <linux/mtd/mtd.h>
16#include <linux/completion.h>
Tim Schmielau4e57b682005-10-30 15:03:48 -080017#include <linux/sched.h>
Nigel Cunningham7dfb7102006-12-06 20:34:23 -080018#include <linux/freezer.h>
Gerard Lledo91e09552009-06-17 13:08:55 -070019#include <linux/kthread.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include "nodelist.h"
21
22
23static int jffs2_garbage_collect_thread(void *);
24
25void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c)
26{
David Woodhouseacb64a42010-05-19 17:00:10 +010027 assert_spin_locked(&c->erase_completion_lock);
David Woodhouseef53cb02007-07-10 10:01:22 +010028 if (c->gc_task && jffs2_thread_should_wake(c))
29 send_sig(SIGHUP, c->gc_task, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -070030}
31
32/* This must only ever be called when no GC thread is currently running */
33int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c)
34{
Gerard Lledo91e09552009-06-17 13:08:55 -070035 struct task_struct *tsk;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 int ret = 0;
37
Eric Sesterhenn4b4d1cc72006-04-01 01:15:35 +020038 BUG_ON(c->gc_task);
Linus Torvalds1da177e2005-04-16 15:20:36 -070039
Thomas Gleixnerfff7afd2005-05-19 17:18:11 +010040 init_completion(&c->gc_thread_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 init_completion(&c->gc_thread_exit);
42
Gerard Lledo91e09552009-06-17 13:08:55 -070043 tsk = kthread_run(jffs2_garbage_collect_thread, c, "jffs2_gcd_mtd%d", c->mtd->index);
44 if (IS_ERR(tsk)) {
45 printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %ld\n", -PTR_ERR(tsk));
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 complete(&c->gc_thread_exit);
Gerard Lledo91e09552009-06-17 13:08:55 -070047 ret = PTR_ERR(tsk);
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 } else {
49 /* Wait for it... */
Gerard Lledo91e09552009-06-17 13:08:55 -070050 D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", tsk->pid));
Thomas Gleixnerfff7afd2005-05-19 17:18:11 +010051 wait_for_completion(&c->gc_thread_start);
Gerard Lledo91e09552009-06-17 13:08:55 -070052 ret = tsk->pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053 }
Thomas Gleixner182ec4e2005-11-07 11:16:07 +000054
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 return ret;
56}
57
58void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c)
59{
Thomas Gleixnere2d48b12005-05-20 22:37:15 +010060 int wait = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 spin_lock(&c->erase_completion_lock);
62 if (c->gc_task) {
63 D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid));
64 send_sig(SIGKILL, c->gc_task, 1);
Thomas Gleixnere2d48b12005-05-20 22:37:15 +010065 wait = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 }
67 spin_unlock(&c->erase_completion_lock);
Thomas Gleixnere2d48b12005-05-20 22:37:15 +010068 if (wait)
69 wait_for_completion(&c->gc_thread_exit);
Linus Torvalds1da177e2005-04-16 15:20:36 -070070}
71
72static int jffs2_garbage_collect_thread(void *_c)
73{
74 struct jffs2_sb_info *c = _c;
75
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 allow_signal(SIGKILL);
77 allow_signal(SIGSTOP);
78 allow_signal(SIGCONT);
79
80 c->gc_task = current;
Thomas Gleixnerfff7afd2005-05-19 17:18:11 +010081 complete(&c->gc_thread_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
83 set_user_nice(current, 10);
84
Rafael J. Wysocki83144182007-07-17 04:03:35 -070085 set_freezable();
Linus Torvalds1da177e2005-04-16 15:20:36 -070086 for (;;) {
87 allow_signal(SIGHUP);
David Woodhousee716dd32007-06-28 19:49:36 +010088 again:
David Woodhouseb27cf882008-10-31 14:52:24 +000089 spin_lock(&c->erase_completion_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 if (!jffs2_thread_should_wake(c)) {
91 set_current_state (TASK_INTERRUPTIBLE);
David Woodhouseb27cf882008-10-31 14:52:24 +000092 spin_unlock(&c->erase_completion_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 schedule();
David Woodhouseb27cf882008-10-31 14:52:24 +000095 } else
96 spin_unlock(&c->erase_completion_lock);
97
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
Andres Salomonefab0b52009-02-11 13:27:02 -080099 /* Problem - immediately after bootup, the GCD spends a lot
100 * of time in places like jffs2_kill_fragtree(); so much so
101 * that userspace processes (like gdm and X) are starved
102 * despite plenty of cond_resched()s and renicing. Yield()
103 * doesn't help, either (presumably because userspace and GCD
104 * are generally competing for a higher latency resource -
105 * disk).
106 * This forces the GCD to slow the hell down. Pulling an
107 * inode in with read_inode() is much preferable to having
108 * the GC thread get there first. */
109 schedule_timeout_interruptible(msecs_to_jiffies(50));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
Gerard Lledo91e09552009-06-17 13:08:55 -0700111 if (kthread_should_stop()) {
112 D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): kthread_stop() called.\n"));
113 goto die;
114 }
115
Thomas Gleixner182ec4e2005-11-07 11:16:07 +0000116 /* Put_super will send a SIGKILL and then wait on the sem.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 */
Rafael J. Wysockie136e762007-12-04 01:11:09 +0100118 while (signal_pending(current) || freezing(current)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 siginfo_t info;
120 unsigned long signr;
121
David Woodhousee716dd32007-06-28 19:49:36 +0100122 if (try_to_freeze())
123 goto again;
124
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 signr = dequeue_signal_lock(current, &current->blocked, &info);
126
127 switch(signr) {
128 case SIGSTOP:
129 D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n"));
130 set_current_state(TASK_STOPPED);
131 schedule();
132 break;
133
134 case SIGKILL:
135 D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n"));
136 goto die;
137
138 case SIGHUP:
139 D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n"));
140 break;
141 default:
142 D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr));
143 }
144 }
145 /* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */
146 disallow_signal(SIGHUP);
147
148 D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n"));
149 if (jffs2_garbage_collect_pass(c) == -ENOSPC) {
150 printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n");
151 goto die;
152 }
153 }
154 die:
155 spin_lock(&c->erase_completion_lock);
156 c->gc_task = NULL;
157 spin_unlock(&c->erase_completion_lock);
158 complete_and_exit(&c->gc_thread_exit, 0);
159}