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1da177e4 LT |
1 | /* |
2 | * JFFS2 -- Journalling Flash File System, Version 2. | |
3 | * | |
c00c310e | 4 | * Copyright © 2001-2007 Red Hat, Inc. |
1da177e4 LT |
5 | * |
6 | * Created by David Woodhouse <dwmw2@infradead.org> | |
7 | * | |
8 | * For licensing information, see the file 'LICENCE' in this directory. | |
9 | * | |
1da177e4 LT |
10 | */ |
11 | ||
12 | #include <linux/kernel.h> | |
13 | #include <linux/jffs2.h> | |
14 | #include <linux/mtd/mtd.h> | |
15 | #include <linux/completion.h> | |
4e57b681 | 16 | #include <linux/sched.h> |
7dfb7103 | 17 | #include <linux/freezer.h> |
1da177e4 LT |
18 | #include "nodelist.h" |
19 | ||
20 | ||
21 | static int jffs2_garbage_collect_thread(void *); | |
22 | ||
23 | void jffs2_garbage_collect_trigger(struct jffs2_sb_info *c) | |
24 | { | |
25 | spin_lock(&c->erase_completion_lock); | |
26 | if (c->gc_task && jffs2_thread_should_wake(c)) | |
27 | send_sig(SIGHUP, c->gc_task, 1); | |
28 | spin_unlock(&c->erase_completion_lock); | |
29 | } | |
30 | ||
31 | /* This must only ever be called when no GC thread is currently running */ | |
32 | int jffs2_start_garbage_collect_thread(struct jffs2_sb_info *c) | |
33 | { | |
34 | pid_t pid; | |
35 | int ret = 0; | |
36 | ||
4b4d1cc7 | 37 | BUG_ON(c->gc_task); |
1da177e4 | 38 | |
fff7afd7 | 39 | init_completion(&c->gc_thread_start); |
1da177e4 LT |
40 | init_completion(&c->gc_thread_exit); |
41 | ||
42 | pid = kernel_thread(jffs2_garbage_collect_thread, c, CLONE_FS|CLONE_FILES); | |
43 | if (pid < 0) { | |
44 | printk(KERN_WARNING "fork failed for JFFS2 garbage collect thread: %d\n", -pid); | |
45 | complete(&c->gc_thread_exit); | |
46 | ret = pid; | |
47 | } else { | |
48 | /* Wait for it... */ | |
49 | D1(printk(KERN_DEBUG "JFFS2: Garbage collect thread is pid %d\n", pid)); | |
fff7afd7 | 50 | wait_for_completion(&c->gc_thread_start); |
1da177e4 | 51 | } |
182ec4ee | 52 | |
1da177e4 LT |
53 | return ret; |
54 | } | |
55 | ||
56 | void jffs2_stop_garbage_collect_thread(struct jffs2_sb_info *c) | |
57 | { | |
e2d48b1a | 58 | int wait = 0; |
1da177e4 LT |
59 | spin_lock(&c->erase_completion_lock); |
60 | if (c->gc_task) { | |
61 | D1(printk(KERN_DEBUG "jffs2: Killing GC task %d\n", c->gc_task->pid)); | |
62 | send_sig(SIGKILL, c->gc_task, 1); | |
e2d48b1a | 63 | wait = 1; |
1da177e4 LT |
64 | } |
65 | spin_unlock(&c->erase_completion_lock); | |
e2d48b1a TG |
66 | if (wait) |
67 | wait_for_completion(&c->gc_thread_exit); | |
1da177e4 LT |
68 | } |
69 | ||
70 | static int jffs2_garbage_collect_thread(void *_c) | |
71 | { | |
72 | struct jffs2_sb_info *c = _c; | |
73 | ||
74 | daemonize("jffs2_gcd_mtd%d", c->mtd->index); | |
75 | allow_signal(SIGKILL); | |
76 | allow_signal(SIGSTOP); | |
77 | allow_signal(SIGCONT); | |
78 | ||
79 | c->gc_task = current; | |
fff7afd7 | 80 | complete(&c->gc_thread_start); |
1da177e4 LT |
81 | |
82 | set_user_nice(current, 10); | |
83 | ||
84 | for (;;) { | |
85 | allow_signal(SIGHUP); | |
86 | ||
87 | if (!jffs2_thread_should_wake(c)) { | |
88 | set_current_state (TASK_INTERRUPTIBLE); | |
89 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread sleeping...\n")); | |
90 | /* Yes, there's a race here; we checked jffs2_thread_should_wake() | |
91 | before setting current->state to TASK_INTERRUPTIBLE. But it doesn't | |
92 | matter - We don't care if we miss a wakeup, because the GC thread | |
93 | is only an optimisation anyway. */ | |
94 | schedule(); | |
95 | } | |
96 | ||
34f18a98 | 97 | if (try_to_freeze()) |
1da177e4 LT |
98 | continue; |
99 | ||
f8a922c7 DW |
100 | /* This thread is purely an optimisation. But if it runs when |
101 | other things could be running, it actually makes things a | |
102 | lot worse. Use yield() and put it at the back of the runqueue | |
103 | every time. Especially during boot, pulling an inode in | |
104 | with read_inode() is much preferable to having the GC thread | |
105 | get there first. */ | |
106 | yield(); | |
1da177e4 | 107 | |
182ec4ee | 108 | /* Put_super will send a SIGKILL and then wait on the sem. |
1da177e4 LT |
109 | */ |
110 | while (signal_pending(current)) { | |
111 | siginfo_t info; | |
112 | unsigned long signr; | |
113 | ||
114 | signr = dequeue_signal_lock(current, ¤t->blocked, &info); | |
115 | ||
116 | switch(signr) { | |
117 | case SIGSTOP: | |
118 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGSTOP received.\n")); | |
119 | set_current_state(TASK_STOPPED); | |
120 | schedule(); | |
121 | break; | |
122 | ||
123 | case SIGKILL: | |
124 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGKILL received.\n")); | |
125 | goto die; | |
126 | ||
127 | case SIGHUP: | |
128 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): SIGHUP received.\n")); | |
129 | break; | |
130 | default: | |
131 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): signal %ld received\n", signr)); | |
132 | } | |
133 | } | |
134 | /* We don't want SIGHUP to interrupt us. STOP and KILL are OK though. */ | |
135 | disallow_signal(SIGHUP); | |
136 | ||
137 | D1(printk(KERN_DEBUG "jffs2_garbage_collect_thread(): pass\n")); | |
138 | if (jffs2_garbage_collect_pass(c) == -ENOSPC) { | |
139 | printk(KERN_NOTICE "No space for garbage collection. Aborting GC thread\n"); | |
140 | goto die; | |
141 | } | |
142 | } | |
143 | die: | |
144 | spin_lock(&c->erase_completion_lock); | |
145 | c->gc_task = NULL; | |
146 | spin_unlock(&c->erase_completion_lock); | |
147 | complete_and_exit(&c->gc_thread_exit, 0); | |
148 | } |