Btrfs: Fix misuse of chunk mutex
[deliverable/linux.git] / fs / btrfs / async-thread.c
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1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
08a9ff32 3 * Copyright (C) 2014 Fujitsu. All rights reserved.
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4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public
7 * License v2 as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public
15 * License along with this program; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 021110-1307, USA.
18 */
19
20#include <linux/kthread.h>
5a0e3ad6 21#include <linux/slab.h>
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22#include <linux/list.h>
23#include <linux/spinlock.h>
b51912c9 24#include <linux/freezer.h>
8b712842 25#include "async-thread.h"
52483bc2 26#include "ctree.h"
8b712842 27
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28#define WORK_DONE_BIT 0
29#define WORK_ORDER_DONE_BIT 1
30#define WORK_HIGH_PRIO_BIT 2
4a69a410 31
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32#define NO_THRESHOLD (-1)
33#define DFT_THRESHOLD (32)
34
d458b054 35struct __btrfs_workqueue {
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36 struct workqueue_struct *normal_wq;
37 /* List head pointing to ordered work list */
38 struct list_head ordered_list;
39
40 /* Spinlock for ordered_list */
41 spinlock_t list_lock;
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42
43 /* Thresholding related variants */
44 atomic_t pending;
45 int max_active;
46 int current_max;
47 int thresh;
48 unsigned int count;
49 spinlock_t thres_lock;
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50};
51
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52struct btrfs_workqueue {
53 struct __btrfs_workqueue *normal;
54 struct __btrfs_workqueue *high;
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55};
56
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57static void normal_work_helper(struct btrfs_work *work);
58
59#define BTRFS_WORK_HELPER(name) \
60void btrfs_##name(struct work_struct *arg) \
61{ \
62 struct btrfs_work *work = container_of(arg, struct btrfs_work, \
63 normal_work); \
64 normal_work_helper(work); \
65}
66
67BTRFS_WORK_HELPER(worker_helper);
68BTRFS_WORK_HELPER(delalloc_helper);
69BTRFS_WORK_HELPER(flush_delalloc_helper);
70BTRFS_WORK_HELPER(cache_helper);
71BTRFS_WORK_HELPER(submit_helper);
72BTRFS_WORK_HELPER(fixup_helper);
73BTRFS_WORK_HELPER(endio_helper);
74BTRFS_WORK_HELPER(endio_meta_helper);
75BTRFS_WORK_HELPER(endio_meta_write_helper);
76BTRFS_WORK_HELPER(endio_raid56_helper);
77BTRFS_WORK_HELPER(rmw_helper);
78BTRFS_WORK_HELPER(endio_write_helper);
79BTRFS_WORK_HELPER(freespace_write_helper);
80BTRFS_WORK_HELPER(delayed_meta_helper);
81BTRFS_WORK_HELPER(readahead_helper);
82BTRFS_WORK_HELPER(qgroup_rescan_helper);
83BTRFS_WORK_HELPER(extent_refs_helper);
84BTRFS_WORK_HELPER(scrub_helper);
85BTRFS_WORK_HELPER(scrubwrc_helper);
86BTRFS_WORK_HELPER(scrubnc_helper);
87
88static struct __btrfs_workqueue *
89__btrfs_alloc_workqueue(const char *name, int flags, int max_active,
c3a46891 90 int thresh)
1ca08976 91{
d458b054 92 struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
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93
94 if (unlikely(!ret))
95 return NULL;
96
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97 ret->max_active = max_active;
98 atomic_set(&ret->pending, 0);
99 if (thresh == 0)
100 thresh = DFT_THRESHOLD;
101 /* For low threshold, disabling threshold is a better choice */
102 if (thresh < DFT_THRESHOLD) {
103 ret->current_max = max_active;
104 ret->thresh = NO_THRESHOLD;
105 } else {
106 ret->current_max = 1;
107 ret->thresh = thresh;
108 }
109
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110 if (flags & WQ_HIGHPRI)
111 ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
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112 ret->max_active,
113 "btrfs", name);
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114 else
115 ret->normal_wq = alloc_workqueue("%s-%s", flags,
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116 ret->max_active, "btrfs",
117 name);
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118 if (unlikely(!ret->normal_wq)) {
119 kfree(ret);
120 return NULL;
121 }
122
123 INIT_LIST_HEAD(&ret->ordered_list);
124 spin_lock_init(&ret->list_lock);
0bd9289c 125 spin_lock_init(&ret->thres_lock);
c3a46891 126 trace_btrfs_workqueue_alloc(ret, name, flags & WQ_HIGHPRI);
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127 return ret;
128}
129
130static inline void
d458b054 131__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
1ca08976 132
c3a46891 133struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
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134 int flags,
135 int max_active,
136 int thresh)
08a9ff32 137{
d458b054 138 struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
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139
140 if (unlikely(!ret))
141 return NULL;
142
1ca08976 143 ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
0bd9289c 144 max_active, thresh);
1ca08976 145 if (unlikely(!ret->normal)) {
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146 kfree(ret);
147 return NULL;
148 }
149
1ca08976 150 if (flags & WQ_HIGHPRI) {
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151 ret->high = __btrfs_alloc_workqueue(name, flags, max_active,
152 thresh);
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153 if (unlikely(!ret->high)) {
154 __btrfs_destroy_workqueue(ret->normal);
155 kfree(ret);
156 return NULL;
157 }
158 }
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159 return ret;
160}
161
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162/*
163 * Hook for threshold which will be called in btrfs_queue_work.
164 * This hook WILL be called in IRQ handler context,
165 * so workqueue_set_max_active MUST NOT be called in this hook
166 */
d458b054 167static inline void thresh_queue_hook(struct __btrfs_workqueue *wq)
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168{
169 if (wq->thresh == NO_THRESHOLD)
170 return;
171 atomic_inc(&wq->pending);
172}
173
174/*
175 * Hook for threshold which will be called before executing the work,
176 * This hook is called in kthread content.
177 * So workqueue_set_max_active is called here.
178 */
d458b054 179static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
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180{
181 int new_max_active;
182 long pending;
183 int need_change = 0;
184
185 if (wq->thresh == NO_THRESHOLD)
186 return;
187
188 atomic_dec(&wq->pending);
189 spin_lock(&wq->thres_lock);
190 /*
191 * Use wq->count to limit the calling frequency of
192 * workqueue_set_max_active.
193 */
194 wq->count++;
195 wq->count %= (wq->thresh / 4);
196 if (!wq->count)
197 goto out;
198 new_max_active = wq->current_max;
199
200 /*
201 * pending may be changed later, but it's OK since we really
202 * don't need it so accurate to calculate new_max_active.
203 */
204 pending = atomic_read(&wq->pending);
205 if (pending > wq->thresh)
206 new_max_active++;
207 if (pending < wq->thresh / 2)
208 new_max_active--;
209 new_max_active = clamp_val(new_max_active, 1, wq->max_active);
210 if (new_max_active != wq->current_max) {
211 need_change = 1;
212 wq->current_max = new_max_active;
213 }
214out:
215 spin_unlock(&wq->thres_lock);
216
217 if (need_change) {
218 workqueue_set_max_active(wq->normal_wq, wq->current_max);
219 }
220}
221
d458b054 222static void run_ordered_work(struct __btrfs_workqueue *wq)
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223{
224 struct list_head *list = &wq->ordered_list;
d458b054 225 struct btrfs_work *work;
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226 spinlock_t *lock = &wq->list_lock;
227 unsigned long flags;
228
229 while (1) {
230 spin_lock_irqsave(lock, flags);
231 if (list_empty(list))
232 break;
d458b054 233 work = list_entry(list->next, struct btrfs_work,
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234 ordered_list);
235 if (!test_bit(WORK_DONE_BIT, &work->flags))
236 break;
237
238 /*
239 * we are going to call the ordered done function, but
240 * we leave the work item on the list as a barrier so
241 * that later work items that are done don't have their
242 * functions called before this one returns
243 */
244 if (test_and_set_bit(WORK_ORDER_DONE_BIT, &work->flags))
245 break;
52483bc2 246 trace_btrfs_ordered_sched(work);
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247 spin_unlock_irqrestore(lock, flags);
248 work->ordered_func(work);
249
250 /* now take the lock again and drop our item from the list */
251 spin_lock_irqsave(lock, flags);
252 list_del(&work->ordered_list);
253 spin_unlock_irqrestore(lock, flags);
254
255 /*
256 * we don't want to call the ordered free functions
257 * with the lock held though
258 */
259 work->ordered_free(work);
52483bc2 260 trace_btrfs_all_work_done(work);
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261 }
262 spin_unlock_irqrestore(lock, flags);
263}
264
9e0af237 265static void normal_work_helper(struct btrfs_work *work)
08a9ff32 266{
d458b054 267 struct __btrfs_workqueue *wq;
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268 int need_order = 0;
269
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270 /*
271 * We should not touch things inside work in the following cases:
272 * 1) after work->func() if it has no ordered_free
273 * Since the struct is freed in work->func().
274 * 2) after setting WORK_DONE_BIT
275 * The work may be freed in other threads almost instantly.
276 * So we save the needed things here.
277 */
278 if (work->ordered_func)
279 need_order = 1;
280 wq = work->wq;
281
52483bc2 282 trace_btrfs_work_sched(work);
0bd9289c 283 thresh_exec_hook(wq);
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284 work->func(work);
285 if (need_order) {
286 set_bit(WORK_DONE_BIT, &work->flags);
287 run_ordered_work(wq);
288 }
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289 if (!need_order)
290 trace_btrfs_all_work_done(work);
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291}
292
9e0af237 293void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t uniq_func,
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294 btrfs_func_t func,
295 btrfs_func_t ordered_func,
296 btrfs_func_t ordered_free)
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297{
298 work->func = func;
299 work->ordered_func = ordered_func;
300 work->ordered_free = ordered_free;
9e0af237 301 INIT_WORK(&work->normal_work, uniq_func);
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302 INIT_LIST_HEAD(&work->ordered_list);
303 work->flags = 0;
304}
305
d458b054
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306static inline void __btrfs_queue_work(struct __btrfs_workqueue *wq,
307 struct btrfs_work *work)
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308{
309 unsigned long flags;
310
311 work->wq = wq;
0bd9289c 312 thresh_queue_hook(wq);
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313 if (work->ordered_func) {
314 spin_lock_irqsave(&wq->list_lock, flags);
315 list_add_tail(&work->ordered_list, &wq->ordered_list);
316 spin_unlock_irqrestore(&wq->list_lock, flags);
317 }
318 queue_work(wq->normal_wq, &work->normal_work);
52483bc2 319 trace_btrfs_work_queued(work);
08a9ff32
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320}
321
d458b054
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322void btrfs_queue_work(struct btrfs_workqueue *wq,
323 struct btrfs_work *work)
1ca08976 324{
d458b054 325 struct __btrfs_workqueue *dest_wq;
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326
327 if (test_bit(WORK_HIGH_PRIO_BIT, &work->flags) && wq->high)
328 dest_wq = wq->high;
329 else
330 dest_wq = wq->normal;
331 __btrfs_queue_work(dest_wq, work);
332}
333
334static inline void
d458b054 335__btrfs_destroy_workqueue(struct __btrfs_workqueue *wq)
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336{
337 destroy_workqueue(wq->normal_wq);
c3a46891 338 trace_btrfs_workqueue_destroy(wq);
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339 kfree(wq);
340}
341
d458b054 342void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
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343{
344 if (!wq)
345 return;
346 if (wq->high)
347 __btrfs_destroy_workqueue(wq->high);
348 __btrfs_destroy_workqueue(wq->normal);
ef66af10 349 kfree(wq);
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350}
351
d458b054 352void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max)
08a9ff32 353{
800ee224
ST
354 if (!wq)
355 return;
0bd9289c 356 wq->normal->max_active = max;
1ca08976 357 if (wq->high)
0bd9289c 358 wq->high->max_active = max;
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359}
360
d458b054 361void btrfs_set_work_high_priority(struct btrfs_work *work)
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362{
363 set_bit(WORK_HIGH_PRIO_BIT, &work->flags);
08a9ff32 364}
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