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Commit | Line | Data |
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3fcfab16 AM |
1 | |
2 | #include <linux/wait.h> | |
3 | #include <linux/backing-dev.h> | |
03ba3782 JA |
4 | #include <linux/kthread.h> |
5 | #include <linux/freezer.h> | |
3fcfab16 | 6 | #include <linux/fs.h> |
26160158 | 7 | #include <linux/pagemap.h> |
03ba3782 | 8 | #include <linux/mm.h> |
3fcfab16 AM |
9 | #include <linux/sched.h> |
10 | #include <linux/module.h> | |
cf0ca9fe PZ |
11 | #include <linux/writeback.h> |
12 | #include <linux/device.h> | |
13 | ||
c3c53206 JA |
14 | static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0); |
15 | ||
26160158 JA |
16 | void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) |
17 | { | |
18 | } | |
19 | EXPORT_SYMBOL(default_unplug_io_fn); | |
20 | ||
21 | struct backing_dev_info default_backing_dev_info = { | |
d993831f | 22 | .name = "default", |
26160158 JA |
23 | .ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE, |
24 | .state = 0, | |
25 | .capabilities = BDI_CAP_MAP_COPY, | |
26 | .unplug_io_fn = default_unplug_io_fn, | |
27 | }; | |
28 | EXPORT_SYMBOL_GPL(default_backing_dev_info); | |
cf0ca9fe | 29 | |
5129a469 JE |
30 | struct backing_dev_info noop_backing_dev_info = { |
31 | .name = "noop", | |
32 | }; | |
33 | EXPORT_SYMBOL_GPL(noop_backing_dev_info); | |
34 | ||
cf0ca9fe | 35 | static struct class *bdi_class; |
cfc4ba53 JA |
36 | |
37 | /* | |
38 | * bdi_lock protects updates to bdi_list and bdi_pending_list, as well as | |
39 | * reader side protection for bdi_pending_list. bdi_list has RCU reader side | |
40 | * locking. | |
41 | */ | |
03ba3782 | 42 | DEFINE_SPINLOCK(bdi_lock); |
66f3b8e2 | 43 | LIST_HEAD(bdi_list); |
03ba3782 JA |
44 | LIST_HEAD(bdi_pending_list); |
45 | ||
46 | static struct task_struct *sync_supers_tsk; | |
47 | static struct timer_list sync_supers_timer; | |
48 | ||
49 | static int bdi_sync_supers(void *); | |
50 | static void sync_supers_timer_fn(unsigned long); | |
03ba3782 JA |
51 | |
52 | static void bdi_add_default_flusher_task(struct backing_dev_info *bdi); | |
cf0ca9fe | 53 | |
76f1418b MS |
54 | #ifdef CONFIG_DEBUG_FS |
55 | #include <linux/debugfs.h> | |
56 | #include <linux/seq_file.h> | |
57 | ||
58 | static struct dentry *bdi_debug_root; | |
59 | ||
60 | static void bdi_debug_init(void) | |
61 | { | |
62 | bdi_debug_root = debugfs_create_dir("bdi", NULL); | |
63 | } | |
64 | ||
65 | static int bdi_debug_stats_show(struct seq_file *m, void *v) | |
66 | { | |
67 | struct backing_dev_info *bdi = m->private; | |
c1955ce3 | 68 | struct bdi_writeback *wb = &bdi->wb; |
364aeb28 DR |
69 | unsigned long background_thresh; |
70 | unsigned long dirty_thresh; | |
71 | unsigned long bdi_thresh; | |
f09b00d3 JA |
72 | unsigned long nr_dirty, nr_io, nr_more_io, nr_wb; |
73 | struct inode *inode; | |
74 | ||
f09b00d3 JA |
75 | nr_wb = nr_dirty = nr_io = nr_more_io = 0; |
76 | spin_lock(&inode_lock); | |
c1955ce3 CH |
77 | list_for_each_entry(inode, &wb->b_dirty, i_list) |
78 | nr_dirty++; | |
79 | list_for_each_entry(inode, &wb->b_io, i_list) | |
80 | nr_io++; | |
81 | list_for_each_entry(inode, &wb->b_more_io, i_list) | |
82 | nr_more_io++; | |
f09b00d3 | 83 | spin_unlock(&inode_lock); |
76f1418b MS |
84 | |
85 | get_dirty_limits(&background_thresh, &dirty_thresh, &bdi_thresh, bdi); | |
86 | ||
87 | #define K(x) ((x) << (PAGE_SHIFT - 10)) | |
88 | seq_printf(m, | |
89 | "BdiWriteback: %8lu kB\n" | |
90 | "BdiReclaimable: %8lu kB\n" | |
91 | "BdiDirtyThresh: %8lu kB\n" | |
92 | "DirtyThresh: %8lu kB\n" | |
f09b00d3 | 93 | "BackgroundThresh: %8lu kB\n" |
f09b00d3 JA |
94 | "b_dirty: %8lu\n" |
95 | "b_io: %8lu\n" | |
96 | "b_more_io: %8lu\n" | |
97 | "bdi_list: %8u\n" | |
c1955ce3 | 98 | "state: %8lx\n", |
76f1418b MS |
99 | (unsigned long) K(bdi_stat(bdi, BDI_WRITEBACK)), |
100 | (unsigned long) K(bdi_stat(bdi, BDI_RECLAIMABLE)), | |
f09b00d3 | 101 | K(bdi_thresh), K(dirty_thresh), |
c1955ce3 CH |
102 | K(background_thresh), nr_dirty, nr_io, nr_more_io, |
103 | !list_empty(&bdi->bdi_list), bdi->state); | |
76f1418b MS |
104 | #undef K |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | static int bdi_debug_stats_open(struct inode *inode, struct file *file) | |
110 | { | |
111 | return single_open(file, bdi_debug_stats_show, inode->i_private); | |
112 | } | |
113 | ||
114 | static const struct file_operations bdi_debug_stats_fops = { | |
115 | .open = bdi_debug_stats_open, | |
116 | .read = seq_read, | |
117 | .llseek = seq_lseek, | |
118 | .release = single_release, | |
119 | }; | |
120 | ||
121 | static void bdi_debug_register(struct backing_dev_info *bdi, const char *name) | |
122 | { | |
123 | bdi->debug_dir = debugfs_create_dir(name, bdi_debug_root); | |
124 | bdi->debug_stats = debugfs_create_file("stats", 0444, bdi->debug_dir, | |
125 | bdi, &bdi_debug_stats_fops); | |
126 | } | |
127 | ||
128 | static void bdi_debug_unregister(struct backing_dev_info *bdi) | |
129 | { | |
130 | debugfs_remove(bdi->debug_stats); | |
131 | debugfs_remove(bdi->debug_dir); | |
132 | } | |
133 | #else | |
134 | static inline void bdi_debug_init(void) | |
135 | { | |
136 | } | |
137 | static inline void bdi_debug_register(struct backing_dev_info *bdi, | |
138 | const char *name) | |
139 | { | |
140 | } | |
141 | static inline void bdi_debug_unregister(struct backing_dev_info *bdi) | |
142 | { | |
143 | } | |
144 | #endif | |
145 | ||
cf0ca9fe PZ |
146 | static ssize_t read_ahead_kb_store(struct device *dev, |
147 | struct device_attribute *attr, | |
148 | const char *buf, size_t count) | |
149 | { | |
150 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
151 | char *end; | |
152 | unsigned long read_ahead_kb; | |
153 | ssize_t ret = -EINVAL; | |
154 | ||
155 | read_ahead_kb = simple_strtoul(buf, &end, 10); | |
156 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { | |
157 | bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10); | |
158 | ret = count; | |
159 | } | |
160 | return ret; | |
161 | } | |
162 | ||
163 | #define K(pages) ((pages) << (PAGE_SHIFT - 10)) | |
164 | ||
165 | #define BDI_SHOW(name, expr) \ | |
166 | static ssize_t name##_show(struct device *dev, \ | |
167 | struct device_attribute *attr, char *page) \ | |
168 | { \ | |
169 | struct backing_dev_info *bdi = dev_get_drvdata(dev); \ | |
170 | \ | |
171 | return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \ | |
172 | } | |
173 | ||
174 | BDI_SHOW(read_ahead_kb, K(bdi->ra_pages)) | |
175 | ||
189d3c4a PZ |
176 | static ssize_t min_ratio_store(struct device *dev, |
177 | struct device_attribute *attr, const char *buf, size_t count) | |
178 | { | |
179 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
180 | char *end; | |
181 | unsigned int ratio; | |
182 | ssize_t ret = -EINVAL; | |
183 | ||
184 | ratio = simple_strtoul(buf, &end, 10); | |
185 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { | |
186 | ret = bdi_set_min_ratio(bdi, ratio); | |
187 | if (!ret) | |
188 | ret = count; | |
189 | } | |
190 | return ret; | |
191 | } | |
192 | BDI_SHOW(min_ratio, bdi->min_ratio) | |
193 | ||
a42dde04 PZ |
194 | static ssize_t max_ratio_store(struct device *dev, |
195 | struct device_attribute *attr, const char *buf, size_t count) | |
196 | { | |
197 | struct backing_dev_info *bdi = dev_get_drvdata(dev); | |
198 | char *end; | |
199 | unsigned int ratio; | |
200 | ssize_t ret = -EINVAL; | |
201 | ||
202 | ratio = simple_strtoul(buf, &end, 10); | |
203 | if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) { | |
204 | ret = bdi_set_max_ratio(bdi, ratio); | |
205 | if (!ret) | |
206 | ret = count; | |
207 | } | |
208 | return ret; | |
209 | } | |
210 | BDI_SHOW(max_ratio, bdi->max_ratio) | |
211 | ||
cf0ca9fe PZ |
212 | #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) |
213 | ||
214 | static struct device_attribute bdi_dev_attrs[] = { | |
215 | __ATTR_RW(read_ahead_kb), | |
189d3c4a | 216 | __ATTR_RW(min_ratio), |
a42dde04 | 217 | __ATTR_RW(max_ratio), |
cf0ca9fe PZ |
218 | __ATTR_NULL, |
219 | }; | |
220 | ||
221 | static __init int bdi_class_init(void) | |
222 | { | |
223 | bdi_class = class_create(THIS_MODULE, "bdi"); | |
14421453 AB |
224 | if (IS_ERR(bdi_class)) |
225 | return PTR_ERR(bdi_class); | |
226 | ||
cf0ca9fe | 227 | bdi_class->dev_attrs = bdi_dev_attrs; |
76f1418b | 228 | bdi_debug_init(); |
cf0ca9fe PZ |
229 | return 0; |
230 | } | |
76f1418b | 231 | postcore_initcall(bdi_class_init); |
cf0ca9fe | 232 | |
26160158 JA |
233 | static int __init default_bdi_init(void) |
234 | { | |
235 | int err; | |
236 | ||
03ba3782 JA |
237 | sync_supers_tsk = kthread_run(bdi_sync_supers, NULL, "sync_supers"); |
238 | BUG_ON(IS_ERR(sync_supers_tsk)); | |
239 | ||
240 | init_timer(&sync_supers_timer); | |
241 | setup_timer(&sync_supers_timer, sync_supers_timer_fn, 0); | |
6423104b | 242 | bdi_arm_supers_timer(); |
03ba3782 | 243 | |
26160158 JA |
244 | err = bdi_init(&default_backing_dev_info); |
245 | if (!err) | |
246 | bdi_register(&default_backing_dev_info, NULL, "default"); | |
247 | ||
248 | return err; | |
249 | } | |
250 | subsys_initcall(default_bdi_init); | |
251 | ||
03ba3782 JA |
252 | static void bdi_wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi) |
253 | { | |
254 | memset(wb, 0, sizeof(*wb)); | |
255 | ||
256 | wb->bdi = bdi; | |
257 | wb->last_old_flush = jiffies; | |
258 | INIT_LIST_HEAD(&wb->b_dirty); | |
259 | INIT_LIST_HEAD(&wb->b_io); | |
260 | INIT_LIST_HEAD(&wb->b_more_io); | |
261 | } | |
262 | ||
03ba3782 JA |
263 | int bdi_has_dirty_io(struct backing_dev_info *bdi) |
264 | { | |
265 | return wb_has_dirty_io(&bdi->wb); | |
266 | } | |
267 | ||
268 | static void bdi_flush_io(struct backing_dev_info *bdi) | |
269 | { | |
270 | struct writeback_control wbc = { | |
03ba3782 JA |
271 | .sync_mode = WB_SYNC_NONE, |
272 | .older_than_this = NULL, | |
273 | .range_cyclic = 1, | |
274 | .nr_to_write = 1024, | |
275 | }; | |
276 | ||
9c3a8ee8 | 277 | writeback_inodes_wb(&bdi->wb, &wbc); |
03ba3782 JA |
278 | } |
279 | ||
280 | /* | |
281 | * kupdated() used to do this. We cannot do it from the bdi_forker_task() | |
282 | * or we risk deadlocking on ->s_umount. The longer term solution would be | |
283 | * to implement sync_supers_bdi() or similar and simply do it from the | |
284 | * bdi writeback tasks individually. | |
285 | */ | |
286 | static int bdi_sync_supers(void *unused) | |
287 | { | |
288 | set_user_nice(current, 0); | |
289 | ||
290 | while (!kthread_should_stop()) { | |
291 | set_current_state(TASK_INTERRUPTIBLE); | |
292 | schedule(); | |
293 | ||
294 | /* | |
295 | * Do this periodically, like kupdated() did before. | |
296 | */ | |
297 | sync_supers(); | |
298 | } | |
299 | ||
300 | return 0; | |
301 | } | |
302 | ||
6423104b | 303 | void bdi_arm_supers_timer(void) |
03ba3782 JA |
304 | { |
305 | unsigned long next; | |
306 | ||
6423104b JA |
307 | if (!dirty_writeback_interval) |
308 | return; | |
309 | ||
03ba3782 JA |
310 | next = msecs_to_jiffies(dirty_writeback_interval * 10) + jiffies; |
311 | mod_timer(&sync_supers_timer, round_jiffies_up(next)); | |
312 | } | |
313 | ||
314 | static void sync_supers_timer_fn(unsigned long unused) | |
315 | { | |
316 | wake_up_process(sync_supers_tsk); | |
6423104b | 317 | bdi_arm_supers_timer(); |
03ba3782 JA |
318 | } |
319 | ||
320 | static int bdi_forker_task(void *ptr) | |
321 | { | |
322 | struct bdi_writeback *me = ptr; | |
323 | ||
c1955ce3 CH |
324 | current->flags |= PF_FLUSHER | PF_SWAPWRITE; |
325 | set_freezable(); | |
326 | ||
327 | /* | |
328 | * Our parent may run at a different priority, just set us to normal | |
329 | */ | |
330 | set_user_nice(current, 0); | |
03ba3782 JA |
331 | |
332 | for (;;) { | |
333 | struct backing_dev_info *bdi, *tmp; | |
334 | struct bdi_writeback *wb; | |
335 | ||
336 | /* | |
337 | * Temporary measure, we want to make sure we don't see | |
338 | * dirty data on the default backing_dev_info | |
339 | */ | |
340 | if (wb_has_dirty_io(me) || !list_empty(&me->bdi->work_list)) | |
341 | wb_do_writeback(me, 0); | |
342 | ||
cfc4ba53 | 343 | spin_lock_bh(&bdi_lock); |
03ba3782 JA |
344 | |
345 | /* | |
346 | * Check if any existing bdi's have dirty data without | |
347 | * a thread registered. If so, set that up. | |
348 | */ | |
349 | list_for_each_entry_safe(bdi, tmp, &bdi_list, bdi_list) { | |
350 | if (bdi->wb.task) | |
351 | continue; | |
352 | if (list_empty(&bdi->work_list) && | |
353 | !bdi_has_dirty_io(bdi)) | |
354 | continue; | |
355 | ||
356 | bdi_add_default_flusher_task(bdi); | |
357 | } | |
358 | ||
359 | set_current_state(TASK_INTERRUPTIBLE); | |
360 | ||
361 | if (list_empty(&bdi_pending_list)) { | |
362 | unsigned long wait; | |
363 | ||
cfc4ba53 | 364 | spin_unlock_bh(&bdi_lock); |
03ba3782 | 365 | wait = msecs_to_jiffies(dirty_writeback_interval * 10); |
6423104b JA |
366 | if (wait) |
367 | schedule_timeout(wait); | |
368 | else | |
369 | schedule(); | |
03ba3782 JA |
370 | try_to_freeze(); |
371 | continue; | |
372 | } | |
373 | ||
374 | __set_current_state(TASK_RUNNING); | |
375 | ||
376 | /* | |
377 | * This is our real job - check for pending entries in | |
378 | * bdi_pending_list, and create the tasks that got added | |
379 | */ | |
380 | bdi = list_entry(bdi_pending_list.next, struct backing_dev_info, | |
381 | bdi_list); | |
382 | list_del_init(&bdi->bdi_list); | |
cfc4ba53 | 383 | spin_unlock_bh(&bdi_lock); |
03ba3782 JA |
384 | |
385 | wb = &bdi->wb; | |
08243900 | 386 | wb->task = kthread_run(bdi_writeback_thread, wb, "flush-%s", |
03ba3782 JA |
387 | dev_name(bdi->dev)); |
388 | /* | |
389 | * If task creation fails, then readd the bdi to | |
390 | * the pending list and force writeout of the bdi | |
391 | * from this forker thread. That will free some memory | |
392 | * and we can try again. | |
393 | */ | |
394 | if (IS_ERR(wb->task)) { | |
395 | wb->task = NULL; | |
396 | ||
397 | /* | |
398 | * Add this 'bdi' to the back, so we get | |
399 | * a chance to flush other bdi's to free | |
400 | * memory. | |
401 | */ | |
cfc4ba53 | 402 | spin_lock_bh(&bdi_lock); |
03ba3782 | 403 | list_add_tail(&bdi->bdi_list, &bdi_pending_list); |
cfc4ba53 | 404 | spin_unlock_bh(&bdi_lock); |
03ba3782 JA |
405 | |
406 | bdi_flush_io(bdi); | |
407 | } | |
408 | } | |
409 | ||
410 | return 0; | |
411 | } | |
412 | ||
cfc4ba53 JA |
413 | static void bdi_add_to_pending(struct rcu_head *head) |
414 | { | |
415 | struct backing_dev_info *bdi; | |
416 | ||
417 | bdi = container_of(head, struct backing_dev_info, rcu_head); | |
418 | INIT_LIST_HEAD(&bdi->bdi_list); | |
419 | ||
420 | spin_lock(&bdi_lock); | |
421 | list_add_tail(&bdi->bdi_list, &bdi_pending_list); | |
422 | spin_unlock(&bdi_lock); | |
423 | ||
424 | /* | |
425 | * We are now on the pending list, wake up bdi_forker_task() | |
426 | * to finish the job and add us back to the active bdi_list | |
427 | */ | |
428 | wake_up_process(default_backing_dev_info.wb.task); | |
429 | } | |
430 | ||
03ba3782 JA |
431 | /* |
432 | * Add the default flusher task that gets created for any bdi | |
433 | * that has dirty data pending writeout | |
434 | */ | |
435 | void static bdi_add_default_flusher_task(struct backing_dev_info *bdi) | |
436 | { | |
437 | if (!bdi_cap_writeback_dirty(bdi)) | |
438 | return; | |
439 | ||
500b067c JA |
440 | if (WARN_ON(!test_bit(BDI_registered, &bdi->state))) { |
441 | printk(KERN_ERR "bdi %p/%s is not registered!\n", | |
442 | bdi, bdi->name); | |
443 | return; | |
444 | } | |
445 | ||
03ba3782 JA |
446 | /* |
447 | * Check with the helper whether to proceed adding a task. Will only | |
448 | * abort if we two or more simultanous calls to | |
449 | * bdi_add_default_flusher_task() occured, further additions will block | |
450 | * waiting for previous additions to finish. | |
451 | */ | |
452 | if (!test_and_set_bit(BDI_pending, &bdi->state)) { | |
cfc4ba53 | 453 | list_del_rcu(&bdi->bdi_list); |
03ba3782 JA |
454 | |
455 | /* | |
cfc4ba53 JA |
456 | * We must wait for the current RCU period to end before |
457 | * moving to the pending list. So schedule that operation | |
458 | * from an RCU callback. | |
03ba3782 | 459 | */ |
cfc4ba53 | 460 | call_rcu(&bdi->rcu_head, bdi_add_to_pending); |
03ba3782 JA |
461 | } |
462 | } | |
463 | ||
cfc4ba53 JA |
464 | /* |
465 | * Remove bdi from bdi_list, and ensure that it is no longer visible | |
466 | */ | |
467 | static void bdi_remove_from_list(struct backing_dev_info *bdi) | |
468 | { | |
469 | spin_lock_bh(&bdi_lock); | |
470 | list_del_rcu(&bdi->bdi_list); | |
471 | spin_unlock_bh(&bdi_lock); | |
472 | ||
473 | synchronize_rcu(); | |
474 | } | |
475 | ||
cf0ca9fe PZ |
476 | int bdi_register(struct backing_dev_info *bdi, struct device *parent, |
477 | const char *fmt, ...) | |
478 | { | |
cf0ca9fe PZ |
479 | va_list args; |
480 | int ret = 0; | |
481 | struct device *dev; | |
482 | ||
69fc208b | 483 | if (bdi->dev) /* The driver needs to use separate queues per device */ |
f1d0b063 KS |
484 | goto exit; |
485 | ||
cf0ca9fe | 486 | va_start(args, fmt); |
19051c50 | 487 | dev = device_create_vargs(bdi_class, parent, MKDEV(0, 0), bdi, fmt, args); |
cf0ca9fe | 488 | va_end(args); |
cf0ca9fe PZ |
489 | if (IS_ERR(dev)) { |
490 | ret = PTR_ERR(dev); | |
491 | goto exit; | |
492 | } | |
493 | ||
cfc4ba53 JA |
494 | spin_lock_bh(&bdi_lock); |
495 | list_add_tail_rcu(&bdi->bdi_list, &bdi_list); | |
496 | spin_unlock_bh(&bdi_lock); | |
66f3b8e2 | 497 | |
cf0ca9fe | 498 | bdi->dev = dev; |
cf0ca9fe | 499 | |
03ba3782 JA |
500 | /* |
501 | * Just start the forker thread for our default backing_dev_info, | |
502 | * and add other bdi's to the list. They will get a thread created | |
503 | * on-demand when they need it. | |
504 | */ | |
505 | if (bdi_cap_flush_forker(bdi)) { | |
506 | struct bdi_writeback *wb = &bdi->wb; | |
507 | ||
508 | wb->task = kthread_run(bdi_forker_task, wb, "bdi-%s", | |
509 | dev_name(dev)); | |
510 | if (IS_ERR(wb->task)) { | |
511 | wb->task = NULL; | |
512 | ret = -ENOMEM; | |
513 | ||
cfc4ba53 | 514 | bdi_remove_from_list(bdi); |
03ba3782 JA |
515 | goto exit; |
516 | } | |
517 | } | |
518 | ||
519 | bdi_debug_register(bdi, dev_name(dev)); | |
500b067c | 520 | set_bit(BDI_registered, &bdi->state); |
cf0ca9fe | 521 | exit: |
cf0ca9fe PZ |
522 | return ret; |
523 | } | |
524 | EXPORT_SYMBOL(bdi_register); | |
525 | ||
526 | int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev) | |
527 | { | |
528 | return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev)); | |
529 | } | |
530 | EXPORT_SYMBOL(bdi_register_dev); | |
531 | ||
03ba3782 JA |
532 | /* |
533 | * Remove bdi from the global list and shutdown any threads we have running | |
534 | */ | |
535 | static void bdi_wb_shutdown(struct backing_dev_info *bdi) | |
66f3b8e2 | 536 | { |
03ba3782 JA |
537 | if (!bdi_cap_writeback_dirty(bdi)) |
538 | return; | |
539 | ||
540 | /* | |
541 | * If setup is pending, wait for that to complete first | |
542 | */ | |
543 | wait_on_bit(&bdi->state, BDI_pending, bdi_sched_wait, | |
544 | TASK_UNINTERRUPTIBLE); | |
545 | ||
546 | /* | |
547 | * Make sure nobody finds us on the bdi_list anymore | |
548 | */ | |
cfc4ba53 | 549 | bdi_remove_from_list(bdi); |
03ba3782 JA |
550 | |
551 | /* | |
c1955ce3 | 552 | * Finally, kill the kernel thread. We don't need to be RCU |
c62b17a5 RD |
553 | * safe anymore, since the bdi is gone from visibility. Force |
554 | * unfreeze of the thread before calling kthread_stop(), otherwise | |
555 | * it would never exet if it is currently stuck in the refrigerator. | |
03ba3782 | 556 | */ |
c1955ce3 CH |
557 | if (bdi->wb.task) { |
558 | thaw_process(bdi->wb.task); | |
559 | kthread_stop(bdi->wb.task); | |
c62b17a5 | 560 | } |
66f3b8e2 JA |
561 | } |
562 | ||
592b09a4 JA |
563 | /* |
564 | * This bdi is going away now, make sure that no super_blocks point to it | |
565 | */ | |
566 | static void bdi_prune_sb(struct backing_dev_info *bdi) | |
567 | { | |
568 | struct super_block *sb; | |
569 | ||
570 | spin_lock(&sb_lock); | |
571 | list_for_each_entry(sb, &super_blocks, s_list) { | |
572 | if (sb->s_bdi == bdi) | |
573 | sb->s_bdi = NULL; | |
574 | } | |
575 | spin_unlock(&sb_lock); | |
576 | } | |
577 | ||
cf0ca9fe PZ |
578 | void bdi_unregister(struct backing_dev_info *bdi) |
579 | { | |
580 | if (bdi->dev) { | |
8c4db335 JA |
581 | bdi_prune_sb(bdi); |
582 | ||
03ba3782 JA |
583 | if (!bdi_cap_flush_forker(bdi)) |
584 | bdi_wb_shutdown(bdi); | |
76f1418b | 585 | bdi_debug_unregister(bdi); |
cf0ca9fe PZ |
586 | device_unregister(bdi->dev); |
587 | bdi->dev = NULL; | |
588 | } | |
589 | } | |
590 | EXPORT_SYMBOL(bdi_unregister); | |
3fcfab16 | 591 | |
b2e8fb6e PZ |
592 | int bdi_init(struct backing_dev_info *bdi) |
593 | { | |
03ba3782 | 594 | int i, err; |
b2e8fb6e | 595 | |
cf0ca9fe PZ |
596 | bdi->dev = NULL; |
597 | ||
189d3c4a | 598 | bdi->min_ratio = 0; |
a42dde04 PZ |
599 | bdi->max_ratio = 100; |
600 | bdi->max_prop_frac = PROP_FRAC_BASE; | |
03ba3782 | 601 | spin_lock_init(&bdi->wb_lock); |
cfc4ba53 | 602 | INIT_RCU_HEAD(&bdi->rcu_head); |
66f3b8e2 | 603 | INIT_LIST_HEAD(&bdi->bdi_list); |
03ba3782 JA |
604 | INIT_LIST_HEAD(&bdi->work_list); |
605 | ||
606 | bdi_wb_init(&bdi->wb, bdi); | |
607 | ||
b2e8fb6e | 608 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { |
ea319518 | 609 | err = percpu_counter_init(&bdi->bdi_stat[i], 0); |
04fbfdc1 PZ |
610 | if (err) |
611 | goto err; | |
612 | } | |
613 | ||
614 | bdi->dirty_exceeded = 0; | |
615 | err = prop_local_init_percpu(&bdi->completions); | |
616 | ||
617 | if (err) { | |
618 | err: | |
4b01a0b1 | 619 | while (i--) |
04fbfdc1 | 620 | percpu_counter_destroy(&bdi->bdi_stat[i]); |
b2e8fb6e PZ |
621 | } |
622 | ||
623 | return err; | |
624 | } | |
625 | EXPORT_SYMBOL(bdi_init); | |
626 | ||
627 | void bdi_destroy(struct backing_dev_info *bdi) | |
628 | { | |
629 | int i; | |
630 | ||
ce5f8e77 JA |
631 | /* |
632 | * Splice our entries to the default_backing_dev_info, if this | |
633 | * bdi disappears | |
634 | */ | |
635 | if (bdi_has_dirty_io(bdi)) { | |
636 | struct bdi_writeback *dst = &default_backing_dev_info.wb; | |
637 | ||
638 | spin_lock(&inode_lock); | |
639 | list_splice(&bdi->wb.b_dirty, &dst->b_dirty); | |
640 | list_splice(&bdi->wb.b_io, &dst->b_io); | |
641 | list_splice(&bdi->wb.b_more_io, &dst->b_more_io); | |
642 | spin_unlock(&inode_lock); | |
643 | } | |
66f3b8e2 | 644 | |
cf0ca9fe PZ |
645 | bdi_unregister(bdi); |
646 | ||
b2e8fb6e PZ |
647 | for (i = 0; i < NR_BDI_STAT_ITEMS; i++) |
648 | percpu_counter_destroy(&bdi->bdi_stat[i]); | |
04fbfdc1 PZ |
649 | |
650 | prop_local_destroy_percpu(&bdi->completions); | |
b2e8fb6e PZ |
651 | } |
652 | EXPORT_SYMBOL(bdi_destroy); | |
653 | ||
c3c53206 JA |
654 | /* |
655 | * For use from filesystems to quickly init and register a bdi associated | |
656 | * with dirty writeback | |
657 | */ | |
658 | int bdi_setup_and_register(struct backing_dev_info *bdi, char *name, | |
659 | unsigned int cap) | |
660 | { | |
661 | char tmp[32]; | |
662 | int err; | |
663 | ||
664 | bdi->name = name; | |
665 | bdi->capabilities = cap; | |
666 | err = bdi_init(bdi); | |
667 | if (err) | |
668 | return err; | |
669 | ||
670 | sprintf(tmp, "%.28s%s", name, "-%d"); | |
671 | err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq)); | |
672 | if (err) { | |
673 | bdi_destroy(bdi); | |
674 | return err; | |
675 | } | |
676 | ||
677 | return 0; | |
678 | } | |
679 | EXPORT_SYMBOL(bdi_setup_and_register); | |
680 | ||
3fcfab16 AM |
681 | static wait_queue_head_t congestion_wqh[2] = { |
682 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), | |
683 | __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) | |
684 | }; | |
685 | ||
1faa16d2 | 686 | void clear_bdi_congested(struct backing_dev_info *bdi, int sync) |
3fcfab16 AM |
687 | { |
688 | enum bdi_state bit; | |
1faa16d2 | 689 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
3fcfab16 | 690 | |
1faa16d2 | 691 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
3fcfab16 AM |
692 | clear_bit(bit, &bdi->state); |
693 | smp_mb__after_clear_bit(); | |
694 | if (waitqueue_active(wqh)) | |
695 | wake_up(wqh); | |
696 | } | |
697 | EXPORT_SYMBOL(clear_bdi_congested); | |
698 | ||
1faa16d2 | 699 | void set_bdi_congested(struct backing_dev_info *bdi, int sync) |
3fcfab16 AM |
700 | { |
701 | enum bdi_state bit; | |
702 | ||
1faa16d2 | 703 | bit = sync ? BDI_sync_congested : BDI_async_congested; |
3fcfab16 AM |
704 | set_bit(bit, &bdi->state); |
705 | } | |
706 | EXPORT_SYMBOL(set_bdi_congested); | |
707 | ||
708 | /** | |
709 | * congestion_wait - wait for a backing_dev to become uncongested | |
8aa7e847 | 710 | * @sync: SYNC or ASYNC IO |
3fcfab16 AM |
711 | * @timeout: timeout in jiffies |
712 | * | |
713 | * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit | |
714 | * write congestion. If no backing_devs are congested then just wait for the | |
715 | * next write to be completed. | |
716 | */ | |
8aa7e847 | 717 | long congestion_wait(int sync, long timeout) |
3fcfab16 AM |
718 | { |
719 | long ret; | |
720 | DEFINE_WAIT(wait); | |
8aa7e847 | 721 | wait_queue_head_t *wqh = &congestion_wqh[sync]; |
3fcfab16 AM |
722 | |
723 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
724 | ret = io_schedule_timeout(timeout); | |
725 | finish_wait(wqh, &wait); | |
726 | return ret; | |
727 | } | |
728 | EXPORT_SYMBOL(congestion_wait); | |
04fbfdc1 | 729 |