Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/fs-writeback.c | |
3 | * | |
4 | * Copyright (C) 2002, Linus Torvalds. | |
5 | * | |
6 | * Contains all the functions related to writing back and waiting | |
7 | * upon dirty inodes against superblocks, and writing back dirty | |
8 | * pages against inodes. ie: data writeback. Writeout of the | |
9 | * inode itself is not handled here. | |
10 | * | |
e1f8e874 | 11 | * 10Apr2002 Andrew Morton |
1da177e4 LT |
12 | * Split out of fs/inode.c |
13 | * Additions for address_space-based writeback | |
14 | */ | |
15 | ||
16 | #include <linux/kernel.h> | |
630d9c47 | 17 | #include <linux/export.h> |
1da177e4 | 18 | #include <linux/spinlock.h> |
5a0e3ad6 | 19 | #include <linux/slab.h> |
1da177e4 LT |
20 | #include <linux/sched.h> |
21 | #include <linux/fs.h> | |
22 | #include <linux/mm.h> | |
bc31b86a | 23 | #include <linux/pagemap.h> |
03ba3782 | 24 | #include <linux/kthread.h> |
1da177e4 LT |
25 | #include <linux/writeback.h> |
26 | #include <linux/blkdev.h> | |
27 | #include <linux/backing-dev.h> | |
455b2864 | 28 | #include <linux/tracepoint.h> |
719ea2fb | 29 | #include <linux/device.h> |
07f3f05c | 30 | #include "internal.h" |
1da177e4 | 31 | |
bc31b86a WF |
32 | /* |
33 | * 4MB minimal write chunk size | |
34 | */ | |
35 | #define MIN_WRITEBACK_PAGES (4096UL >> (PAGE_CACHE_SHIFT - 10)) | |
36 | ||
c4a77a6c JA |
37 | /* |
38 | * Passed into wb_writeback(), essentially a subset of writeback_control | |
39 | */ | |
83ba7b07 | 40 | struct wb_writeback_work { |
c4a77a6c JA |
41 | long nr_pages; |
42 | struct super_block *sb; | |
0dc83bd3 | 43 | unsigned long *older_than_this; |
c4a77a6c | 44 | enum writeback_sync_modes sync_mode; |
6e6938b6 | 45 | unsigned int tagged_writepages:1; |
52957fe1 HS |
46 | unsigned int for_kupdate:1; |
47 | unsigned int range_cyclic:1; | |
48 | unsigned int for_background:1; | |
7747bd4b | 49 | unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ |
0e175a18 | 50 | enum wb_reason reason; /* why was writeback initiated? */ |
c4a77a6c | 51 | |
8010c3b6 | 52 | struct list_head list; /* pending work list */ |
83ba7b07 | 53 | struct completion *done; /* set if the caller waits */ |
03ba3782 JA |
54 | }; |
55 | ||
a2f48706 TT |
56 | /* |
57 | * If an inode is constantly having its pages dirtied, but then the | |
58 | * updates stop dirtytime_expire_interval seconds in the past, it's | |
59 | * possible for the worst case time between when an inode has its | |
60 | * timestamps updated and when they finally get written out to be two | |
61 | * dirtytime_expire_intervals. We set the default to 12 hours (in | |
62 | * seconds), which means most of the time inodes will have their | |
63 | * timestamps written to disk after 12 hours, but in the worst case a | |
64 | * few inodes might not their timestamps updated for 24 hours. | |
65 | */ | |
66 | unsigned int dirtytime_expire_interval = 12 * 60 * 60; | |
67 | ||
f11b00f3 AB |
68 | /** |
69 | * writeback_in_progress - determine whether there is writeback in progress | |
70 | * @bdi: the device's backing_dev_info structure. | |
71 | * | |
03ba3782 JA |
72 | * Determine whether there is writeback waiting to be handled against a |
73 | * backing device. | |
f11b00f3 AB |
74 | */ |
75 | int writeback_in_progress(struct backing_dev_info *bdi) | |
76 | { | |
81d73a32 | 77 | return test_bit(BDI_writeback_running, &bdi->state); |
f11b00f3 | 78 | } |
00d4e736 | 79 | EXPORT_SYMBOL(writeback_in_progress); |
f11b00f3 | 80 | |
de1414a6 | 81 | struct backing_dev_info *inode_to_bdi(struct inode *inode) |
692ebd17 | 82 | { |
b520252a JA |
83 | struct super_block *sb; |
84 | ||
85 | if (!inode) | |
86 | return &noop_backing_dev_info; | |
87 | ||
88 | sb = inode->i_sb; | |
495a276e | 89 | #ifdef CONFIG_BLOCK |
a8855990 | 90 | if (sb_is_blkdev_sb(sb)) |
495a276e CH |
91 | return blk_get_backing_dev_info(I_BDEV(inode)); |
92 | #endif | |
aaead25b | 93 | return sb->s_bdi; |
692ebd17 | 94 | } |
de1414a6 | 95 | EXPORT_SYMBOL_GPL(inode_to_bdi); |
692ebd17 | 96 | |
7ccf19a8 NP |
97 | static inline struct inode *wb_inode(struct list_head *head) |
98 | { | |
99 | return list_entry(head, struct inode, i_wb_list); | |
100 | } | |
101 | ||
15eb77a0 WF |
102 | /* |
103 | * Include the creation of the trace points after defining the | |
104 | * wb_writeback_work structure and inline functions so that the definition | |
105 | * remains local to this file. | |
106 | */ | |
107 | #define CREATE_TRACE_POINTS | |
108 | #include <trace/events/writeback.h> | |
109 | ||
774016b2 SW |
110 | EXPORT_TRACEPOINT_SYMBOL_GPL(wbc_writepage); |
111 | ||
5acda9d1 JK |
112 | static void bdi_wakeup_thread(struct backing_dev_info *bdi) |
113 | { | |
114 | spin_lock_bh(&bdi->wb_lock); | |
115 | if (test_bit(BDI_registered, &bdi->state)) | |
116 | mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); | |
117 | spin_unlock_bh(&bdi->wb_lock); | |
118 | } | |
119 | ||
6585027a JK |
120 | static void bdi_queue_work(struct backing_dev_info *bdi, |
121 | struct wb_writeback_work *work) | |
122 | { | |
123 | trace_writeback_queue(bdi, work); | |
124 | ||
125 | spin_lock_bh(&bdi->wb_lock); | |
5acda9d1 JK |
126 | if (!test_bit(BDI_registered, &bdi->state)) { |
127 | if (work->done) | |
128 | complete(work->done); | |
129 | goto out_unlock; | |
130 | } | |
6585027a | 131 | list_add_tail(&work->list, &bdi->work_list); |
839a8e86 | 132 | mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); |
5acda9d1 JK |
133 | out_unlock: |
134 | spin_unlock_bh(&bdi->wb_lock); | |
1da177e4 LT |
135 | } |
136 | ||
83ba7b07 CH |
137 | static void |
138 | __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, | |
0e175a18 | 139 | bool range_cyclic, enum wb_reason reason) |
1da177e4 | 140 | { |
83ba7b07 | 141 | struct wb_writeback_work *work; |
03ba3782 | 142 | |
bcddc3f0 JA |
143 | /* |
144 | * This is WB_SYNC_NONE writeback, so if allocation fails just | |
145 | * wakeup the thread for old dirty data writeback | |
146 | */ | |
83ba7b07 CH |
147 | work = kzalloc(sizeof(*work), GFP_ATOMIC); |
148 | if (!work) { | |
839a8e86 | 149 | trace_writeback_nowork(bdi); |
5acda9d1 | 150 | bdi_wakeup_thread(bdi); |
83ba7b07 | 151 | return; |
bcddc3f0 | 152 | } |
03ba3782 | 153 | |
83ba7b07 CH |
154 | work->sync_mode = WB_SYNC_NONE; |
155 | work->nr_pages = nr_pages; | |
156 | work->range_cyclic = range_cyclic; | |
0e175a18 | 157 | work->reason = reason; |
03ba3782 | 158 | |
83ba7b07 | 159 | bdi_queue_work(bdi, work); |
b6e51316 JA |
160 | } |
161 | ||
162 | /** | |
163 | * bdi_start_writeback - start writeback | |
164 | * @bdi: the backing device to write from | |
165 | * @nr_pages: the number of pages to write | |
786228ab | 166 | * @reason: reason why some writeback work was initiated |
b6e51316 JA |
167 | * |
168 | * Description: | |
169 | * This does WB_SYNC_NONE opportunistic writeback. The IO is only | |
25985edc | 170 | * started when this function returns, we make no guarantees on |
0e3c9a22 | 171 | * completion. Caller need not hold sb s_umount semaphore. |
b6e51316 JA |
172 | * |
173 | */ | |
0e175a18 CW |
174 | void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, |
175 | enum wb_reason reason) | |
b6e51316 | 176 | { |
0e175a18 | 177 | __bdi_start_writeback(bdi, nr_pages, true, reason); |
c5444198 | 178 | } |
d3ddec76 | 179 | |
c5444198 CH |
180 | /** |
181 | * bdi_start_background_writeback - start background writeback | |
182 | * @bdi: the backing device to write from | |
183 | * | |
184 | * Description: | |
6585027a JK |
185 | * This makes sure WB_SYNC_NONE background writeback happens. When |
186 | * this function returns, it is only guaranteed that for given BDI | |
187 | * some IO is happening if we are over background dirty threshold. | |
188 | * Caller need not hold sb s_umount semaphore. | |
c5444198 CH |
189 | */ |
190 | void bdi_start_background_writeback(struct backing_dev_info *bdi) | |
191 | { | |
6585027a JK |
192 | /* |
193 | * We just wake up the flusher thread. It will perform background | |
194 | * writeback as soon as there is no other work to do. | |
195 | */ | |
71927e84 | 196 | trace_writeback_wake_background(bdi); |
5acda9d1 | 197 | bdi_wakeup_thread(bdi); |
1da177e4 LT |
198 | } |
199 | ||
a66979ab DC |
200 | /* |
201 | * Remove the inode from the writeback list it is on. | |
202 | */ | |
203 | void inode_wb_list_del(struct inode *inode) | |
204 | { | |
f758eeab CH |
205 | struct backing_dev_info *bdi = inode_to_bdi(inode); |
206 | ||
207 | spin_lock(&bdi->wb.list_lock); | |
a66979ab | 208 | list_del_init(&inode->i_wb_list); |
f758eeab | 209 | spin_unlock(&bdi->wb.list_lock); |
a66979ab DC |
210 | } |
211 | ||
6610a0bc AM |
212 | /* |
213 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the | |
214 | * furthest end of its superblock's dirty-inode list. | |
215 | * | |
216 | * Before stamping the inode's ->dirtied_when, we check to see whether it is | |
66f3b8e2 | 217 | * already the most-recently-dirtied inode on the b_dirty list. If that is |
6610a0bc AM |
218 | * the case then the inode must have been redirtied while it was being written |
219 | * out and we don't reset its dirtied_when. | |
220 | */ | |
f758eeab | 221 | static void redirty_tail(struct inode *inode, struct bdi_writeback *wb) |
6610a0bc | 222 | { |
f758eeab | 223 | assert_spin_locked(&wb->list_lock); |
03ba3782 | 224 | if (!list_empty(&wb->b_dirty)) { |
66f3b8e2 | 225 | struct inode *tail; |
6610a0bc | 226 | |
7ccf19a8 | 227 | tail = wb_inode(wb->b_dirty.next); |
66f3b8e2 | 228 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
6610a0bc AM |
229 | inode->dirtied_when = jiffies; |
230 | } | |
7ccf19a8 | 231 | list_move(&inode->i_wb_list, &wb->b_dirty); |
6610a0bc AM |
232 | } |
233 | ||
c986d1e2 | 234 | /* |
66f3b8e2 | 235 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
c986d1e2 | 236 | */ |
f758eeab | 237 | static void requeue_io(struct inode *inode, struct bdi_writeback *wb) |
c986d1e2 | 238 | { |
f758eeab | 239 | assert_spin_locked(&wb->list_lock); |
7ccf19a8 | 240 | list_move(&inode->i_wb_list, &wb->b_more_io); |
c986d1e2 AM |
241 | } |
242 | ||
1c0eeaf5 JE |
243 | static void inode_sync_complete(struct inode *inode) |
244 | { | |
365b94ae | 245 | inode->i_state &= ~I_SYNC; |
4eff96dd JK |
246 | /* If inode is clean an unused, put it into LRU now... */ |
247 | inode_add_lru(inode); | |
365b94ae | 248 | /* Waiters must see I_SYNC cleared before being woken up */ |
1c0eeaf5 JE |
249 | smp_mb(); |
250 | wake_up_bit(&inode->i_state, __I_SYNC); | |
251 | } | |
252 | ||
d2caa3c5 JL |
253 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
254 | { | |
255 | bool ret = time_after(inode->dirtied_when, t); | |
256 | #ifndef CONFIG_64BIT | |
257 | /* | |
258 | * For inodes being constantly redirtied, dirtied_when can get stuck. | |
259 | * It _appears_ to be in the future, but is actually in distant past. | |
260 | * This test is necessary to prevent such wrapped-around relative times | |
5b0830cb | 261 | * from permanently stopping the whole bdi writeback. |
d2caa3c5 JL |
262 | */ |
263 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); | |
264 | #endif | |
265 | return ret; | |
266 | } | |
267 | ||
0ae45f63 TT |
268 | #define EXPIRE_DIRTY_ATIME 0x0001 |
269 | ||
2c136579 | 270 | /* |
0e2f2b23 | 271 | * Move expired (dirtied before work->older_than_this) dirty inodes from |
697e6fed | 272 | * @delaying_queue to @dispatch_queue. |
2c136579 | 273 | */ |
e84d0a4f | 274 | static int move_expired_inodes(struct list_head *delaying_queue, |
2c136579 | 275 | struct list_head *dispatch_queue, |
0ae45f63 | 276 | int flags, |
ad4e38dd | 277 | struct wb_writeback_work *work) |
2c136579 | 278 | { |
0ae45f63 TT |
279 | unsigned long *older_than_this = NULL; |
280 | unsigned long expire_time; | |
5c03449d SL |
281 | LIST_HEAD(tmp); |
282 | struct list_head *pos, *node; | |
cf137307 | 283 | struct super_block *sb = NULL; |
5c03449d | 284 | struct inode *inode; |
cf137307 | 285 | int do_sb_sort = 0; |
e84d0a4f | 286 | int moved = 0; |
5c03449d | 287 | |
0ae45f63 TT |
288 | if ((flags & EXPIRE_DIRTY_ATIME) == 0) |
289 | older_than_this = work->older_than_this; | |
a2f48706 TT |
290 | else if (!work->for_sync) { |
291 | expire_time = jiffies - (dirtytime_expire_interval * HZ); | |
0ae45f63 TT |
292 | older_than_this = &expire_time; |
293 | } | |
2c136579 | 294 | while (!list_empty(delaying_queue)) { |
7ccf19a8 | 295 | inode = wb_inode(delaying_queue->prev); |
0ae45f63 TT |
296 | if (older_than_this && |
297 | inode_dirtied_after(inode, *older_than_this)) | |
2c136579 | 298 | break; |
a8855990 JK |
299 | list_move(&inode->i_wb_list, &tmp); |
300 | moved++; | |
0ae45f63 TT |
301 | if (flags & EXPIRE_DIRTY_ATIME) |
302 | set_bit(__I_DIRTY_TIME_EXPIRED, &inode->i_state); | |
a8855990 JK |
303 | if (sb_is_blkdev_sb(inode->i_sb)) |
304 | continue; | |
cf137307 JA |
305 | if (sb && sb != inode->i_sb) |
306 | do_sb_sort = 1; | |
307 | sb = inode->i_sb; | |
5c03449d SL |
308 | } |
309 | ||
cf137307 JA |
310 | /* just one sb in list, splice to dispatch_queue and we're done */ |
311 | if (!do_sb_sort) { | |
312 | list_splice(&tmp, dispatch_queue); | |
e84d0a4f | 313 | goto out; |
cf137307 JA |
314 | } |
315 | ||
5c03449d SL |
316 | /* Move inodes from one superblock together */ |
317 | while (!list_empty(&tmp)) { | |
7ccf19a8 | 318 | sb = wb_inode(tmp.prev)->i_sb; |
5c03449d | 319 | list_for_each_prev_safe(pos, node, &tmp) { |
7ccf19a8 | 320 | inode = wb_inode(pos); |
5c03449d | 321 | if (inode->i_sb == sb) |
7ccf19a8 | 322 | list_move(&inode->i_wb_list, dispatch_queue); |
5c03449d | 323 | } |
2c136579 | 324 | } |
e84d0a4f WF |
325 | out: |
326 | return moved; | |
2c136579 FW |
327 | } |
328 | ||
329 | /* | |
330 | * Queue all expired dirty inodes for io, eldest first. | |
4ea879b9 WF |
331 | * Before |
332 | * newly dirtied b_dirty b_io b_more_io | |
333 | * =============> gf edc BA | |
334 | * After | |
335 | * newly dirtied b_dirty b_io b_more_io | |
336 | * =============> g fBAedc | |
337 | * | | |
338 | * +--> dequeue for IO | |
2c136579 | 339 | */ |
ad4e38dd | 340 | static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work) |
66f3b8e2 | 341 | { |
e84d0a4f | 342 | int moved; |
0ae45f63 | 343 | |
f758eeab | 344 | assert_spin_locked(&wb->list_lock); |
4ea879b9 | 345 | list_splice_init(&wb->b_more_io, &wb->b_io); |
0ae45f63 TT |
346 | moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, 0, work); |
347 | moved += move_expired_inodes(&wb->b_dirty_time, &wb->b_io, | |
348 | EXPIRE_DIRTY_ATIME, work); | |
ad4e38dd | 349 | trace_writeback_queue_io(wb, work, moved); |
66f3b8e2 JA |
350 | } |
351 | ||
a9185b41 | 352 | static int write_inode(struct inode *inode, struct writeback_control *wbc) |
08d8e974 | 353 | { |
9fb0a7da TH |
354 | int ret; |
355 | ||
356 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) { | |
357 | trace_writeback_write_inode_start(inode, wbc); | |
358 | ret = inode->i_sb->s_op->write_inode(inode, wbc); | |
359 | trace_writeback_write_inode(inode, wbc); | |
360 | return ret; | |
361 | } | |
03ba3782 | 362 | return 0; |
08d8e974 | 363 | } |
08d8e974 | 364 | |
1da177e4 | 365 | /* |
169ebd90 JK |
366 | * Wait for writeback on an inode to complete. Called with i_lock held. |
367 | * Caller must make sure inode cannot go away when we drop i_lock. | |
01c03194 | 368 | */ |
169ebd90 JK |
369 | static void __inode_wait_for_writeback(struct inode *inode) |
370 | __releases(inode->i_lock) | |
371 | __acquires(inode->i_lock) | |
01c03194 CH |
372 | { |
373 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); | |
374 | wait_queue_head_t *wqh; | |
375 | ||
376 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
250df6ed DC |
377 | while (inode->i_state & I_SYNC) { |
378 | spin_unlock(&inode->i_lock); | |
74316201 N |
379 | __wait_on_bit(wqh, &wq, bit_wait, |
380 | TASK_UNINTERRUPTIBLE); | |
250df6ed | 381 | spin_lock(&inode->i_lock); |
58a9d3d8 | 382 | } |
01c03194 CH |
383 | } |
384 | ||
169ebd90 JK |
385 | /* |
386 | * Wait for writeback on an inode to complete. Caller must have inode pinned. | |
387 | */ | |
388 | void inode_wait_for_writeback(struct inode *inode) | |
389 | { | |
390 | spin_lock(&inode->i_lock); | |
391 | __inode_wait_for_writeback(inode); | |
392 | spin_unlock(&inode->i_lock); | |
393 | } | |
394 | ||
395 | /* | |
396 | * Sleep until I_SYNC is cleared. This function must be called with i_lock | |
397 | * held and drops it. It is aimed for callers not holding any inode reference | |
398 | * so once i_lock is dropped, inode can go away. | |
399 | */ | |
400 | static void inode_sleep_on_writeback(struct inode *inode) | |
401 | __releases(inode->i_lock) | |
402 | { | |
403 | DEFINE_WAIT(wait); | |
404 | wait_queue_head_t *wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
405 | int sleep; | |
406 | ||
407 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
408 | sleep = inode->i_state & I_SYNC; | |
409 | spin_unlock(&inode->i_lock); | |
410 | if (sleep) | |
411 | schedule(); | |
412 | finish_wait(wqh, &wait); | |
413 | } | |
414 | ||
ccb26b5a JK |
415 | /* |
416 | * Find proper writeback list for the inode depending on its current state and | |
417 | * possibly also change of its state while we were doing writeback. Here we | |
418 | * handle things such as livelock prevention or fairness of writeback among | |
419 | * inodes. This function can be called only by flusher thread - noone else | |
420 | * processes all inodes in writeback lists and requeueing inodes behind flusher | |
421 | * thread's back can have unexpected consequences. | |
422 | */ | |
423 | static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, | |
424 | struct writeback_control *wbc) | |
425 | { | |
426 | if (inode->i_state & I_FREEING) | |
427 | return; | |
428 | ||
429 | /* | |
430 | * Sync livelock prevention. Each inode is tagged and synced in one | |
431 | * shot. If still dirty, it will be redirty_tail()'ed below. Update | |
432 | * the dirty time to prevent enqueue and sync it again. | |
433 | */ | |
434 | if ((inode->i_state & I_DIRTY) && | |
435 | (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)) | |
436 | inode->dirtied_when = jiffies; | |
437 | ||
4f8ad655 JK |
438 | if (wbc->pages_skipped) { |
439 | /* | |
440 | * writeback is not making progress due to locked | |
441 | * buffers. Skip this inode for now. | |
442 | */ | |
443 | redirty_tail(inode, wb); | |
444 | return; | |
445 | } | |
446 | ||
ccb26b5a JK |
447 | if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) { |
448 | /* | |
449 | * We didn't write back all the pages. nfs_writepages() | |
450 | * sometimes bales out without doing anything. | |
451 | */ | |
452 | if (wbc->nr_to_write <= 0) { | |
453 | /* Slice used up. Queue for next turn. */ | |
454 | requeue_io(inode, wb); | |
455 | } else { | |
456 | /* | |
457 | * Writeback blocked by something other than | |
458 | * congestion. Delay the inode for some time to | |
459 | * avoid spinning on the CPU (100% iowait) | |
460 | * retrying writeback of the dirty page/inode | |
461 | * that cannot be performed immediately. | |
462 | */ | |
463 | redirty_tail(inode, wb); | |
464 | } | |
465 | } else if (inode->i_state & I_DIRTY) { | |
466 | /* | |
467 | * Filesystems can dirty the inode during writeback operations, | |
468 | * such as delayed allocation during submission or metadata | |
469 | * updates after data IO completion. | |
470 | */ | |
471 | redirty_tail(inode, wb); | |
0ae45f63 | 472 | } else if (inode->i_state & I_DIRTY_TIME) { |
a2f48706 | 473 | inode->dirtied_when = jiffies; |
0ae45f63 | 474 | list_move(&inode->i_wb_list, &wb->b_dirty_time); |
ccb26b5a JK |
475 | } else { |
476 | /* The inode is clean. Remove from writeback lists. */ | |
477 | list_del_init(&inode->i_wb_list); | |
478 | } | |
479 | } | |
480 | ||
01c03194 | 481 | /* |
4f8ad655 JK |
482 | * Write out an inode and its dirty pages. Do not update the writeback list |
483 | * linkage. That is left to the caller. The caller is also responsible for | |
484 | * setting I_SYNC flag and calling inode_sync_complete() to clear it. | |
1da177e4 LT |
485 | */ |
486 | static int | |
cd8ed2a4 | 487 | __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
1da177e4 | 488 | { |
1da177e4 | 489 | struct address_space *mapping = inode->i_mapping; |
251d6a47 | 490 | long nr_to_write = wbc->nr_to_write; |
01c03194 | 491 | unsigned dirty; |
1da177e4 LT |
492 | int ret; |
493 | ||
4f8ad655 | 494 | WARN_ON(!(inode->i_state & I_SYNC)); |
1da177e4 | 495 | |
9fb0a7da TH |
496 | trace_writeback_single_inode_start(inode, wbc, nr_to_write); |
497 | ||
1da177e4 LT |
498 | ret = do_writepages(mapping, wbc); |
499 | ||
26821ed4 CH |
500 | /* |
501 | * Make sure to wait on the data before writing out the metadata. | |
502 | * This is important for filesystems that modify metadata on data | |
7747bd4b DC |
503 | * I/O completion. We don't do it for sync(2) writeback because it has a |
504 | * separate, external IO completion path and ->sync_fs for guaranteeing | |
505 | * inode metadata is written back correctly. | |
26821ed4 | 506 | */ |
7747bd4b | 507 | if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync) { |
26821ed4 | 508 | int err = filemap_fdatawait(mapping); |
1da177e4 LT |
509 | if (ret == 0) |
510 | ret = err; | |
511 | } | |
512 | ||
5547e8aa DM |
513 | /* |
514 | * Some filesystems may redirty the inode during the writeback | |
515 | * due to delalloc, clear dirty metadata flags right before | |
516 | * write_inode() | |
517 | */ | |
250df6ed | 518 | spin_lock(&inode->i_lock); |
9c6ac78e | 519 | |
5547e8aa | 520 | dirty = inode->i_state & I_DIRTY; |
a2f48706 TT |
521 | if (inode->i_state & I_DIRTY_TIME) { |
522 | if ((dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) || | |
523 | unlikely(inode->i_state & I_DIRTY_TIME_EXPIRED) || | |
524 | unlikely(time_after(jiffies, | |
525 | (inode->dirtied_time_when + | |
526 | dirtytime_expire_interval * HZ)))) { | |
527 | dirty |= I_DIRTY_TIME | I_DIRTY_TIME_EXPIRED; | |
528 | trace_writeback_lazytime(inode); | |
529 | } | |
530 | } else | |
531 | inode->i_state &= ~I_DIRTY_TIME_EXPIRED; | |
0ae45f63 | 532 | inode->i_state &= ~dirty; |
9c6ac78e TH |
533 | |
534 | /* | |
535 | * Paired with smp_mb() in __mark_inode_dirty(). This allows | |
536 | * __mark_inode_dirty() to test i_state without grabbing i_lock - | |
537 | * either they see the I_DIRTY bits cleared or we see the dirtied | |
538 | * inode. | |
539 | * | |
540 | * I_DIRTY_PAGES is always cleared together above even if @mapping | |
541 | * still has dirty pages. The flag is reinstated after smp_mb() if | |
542 | * necessary. This guarantees that either __mark_inode_dirty() | |
543 | * sees clear I_DIRTY_PAGES or we see PAGECACHE_TAG_DIRTY. | |
544 | */ | |
545 | smp_mb(); | |
546 | ||
547 | if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) | |
548 | inode->i_state |= I_DIRTY_PAGES; | |
549 | ||
250df6ed | 550 | spin_unlock(&inode->i_lock); |
9c6ac78e | 551 | |
0ae45f63 TT |
552 | if (dirty & I_DIRTY_TIME) |
553 | mark_inode_dirty_sync(inode); | |
26821ed4 | 554 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
0ae45f63 | 555 | if (dirty & ~I_DIRTY_PAGES) { |
a9185b41 | 556 | int err = write_inode(inode, wbc); |
1da177e4 LT |
557 | if (ret == 0) |
558 | ret = err; | |
559 | } | |
4f8ad655 JK |
560 | trace_writeback_single_inode(inode, wbc, nr_to_write); |
561 | return ret; | |
562 | } | |
563 | ||
564 | /* | |
565 | * Write out an inode's dirty pages. Either the caller has an active reference | |
566 | * on the inode or the inode has I_WILL_FREE set. | |
567 | * | |
568 | * This function is designed to be called for writing back one inode which | |
569 | * we go e.g. from filesystem. Flusher thread uses __writeback_single_inode() | |
570 | * and does more profound writeback list handling in writeback_sb_inodes(). | |
571 | */ | |
572 | static int | |
573 | writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, | |
574 | struct writeback_control *wbc) | |
575 | { | |
576 | int ret = 0; | |
577 | ||
578 | spin_lock(&inode->i_lock); | |
579 | if (!atomic_read(&inode->i_count)) | |
580 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); | |
581 | else | |
582 | WARN_ON(inode->i_state & I_WILL_FREE); | |
583 | ||
584 | if (inode->i_state & I_SYNC) { | |
585 | if (wbc->sync_mode != WB_SYNC_ALL) | |
586 | goto out; | |
587 | /* | |
169ebd90 JK |
588 | * It's a data-integrity sync. We must wait. Since callers hold |
589 | * inode reference or inode has I_WILL_FREE set, it cannot go | |
590 | * away under us. | |
4f8ad655 | 591 | */ |
169ebd90 | 592 | __inode_wait_for_writeback(inode); |
4f8ad655 JK |
593 | } |
594 | WARN_ON(inode->i_state & I_SYNC); | |
595 | /* | |
f9b0e058 JK |
596 | * Skip inode if it is clean and we have no outstanding writeback in |
597 | * WB_SYNC_ALL mode. We don't want to mess with writeback lists in this | |
598 | * function since flusher thread may be doing for example sync in | |
599 | * parallel and if we move the inode, it could get skipped. So here we | |
600 | * make sure inode is on some writeback list and leave it there unless | |
601 | * we have completely cleaned the inode. | |
4f8ad655 | 602 | */ |
0ae45f63 | 603 | if (!(inode->i_state & I_DIRTY_ALL) && |
f9b0e058 JK |
604 | (wbc->sync_mode != WB_SYNC_ALL || |
605 | !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))) | |
4f8ad655 JK |
606 | goto out; |
607 | inode->i_state |= I_SYNC; | |
608 | spin_unlock(&inode->i_lock); | |
609 | ||
cd8ed2a4 | 610 | ret = __writeback_single_inode(inode, wbc); |
1da177e4 | 611 | |
f758eeab | 612 | spin_lock(&wb->list_lock); |
250df6ed | 613 | spin_lock(&inode->i_lock); |
4f8ad655 JK |
614 | /* |
615 | * If inode is clean, remove it from writeback lists. Otherwise don't | |
616 | * touch it. See comment above for explanation. | |
617 | */ | |
0ae45f63 | 618 | if (!(inode->i_state & I_DIRTY_ALL)) |
4f8ad655 JK |
619 | list_del_init(&inode->i_wb_list); |
620 | spin_unlock(&wb->list_lock); | |
1c0eeaf5 | 621 | inode_sync_complete(inode); |
4f8ad655 JK |
622 | out: |
623 | spin_unlock(&inode->i_lock); | |
1da177e4 LT |
624 | return ret; |
625 | } | |
626 | ||
1a12d8bd WF |
627 | static long writeback_chunk_size(struct backing_dev_info *bdi, |
628 | struct wb_writeback_work *work) | |
d46db3d5 WF |
629 | { |
630 | long pages; | |
631 | ||
632 | /* | |
633 | * WB_SYNC_ALL mode does livelock avoidance by syncing dirty | |
634 | * inodes/pages in one big loop. Setting wbc.nr_to_write=LONG_MAX | |
635 | * here avoids calling into writeback_inodes_wb() more than once. | |
636 | * | |
637 | * The intended call sequence for WB_SYNC_ALL writeback is: | |
638 | * | |
639 | * wb_writeback() | |
640 | * writeback_sb_inodes() <== called only once | |
641 | * write_cache_pages() <== called once for each inode | |
642 | * (quickly) tag currently dirty pages | |
643 | * (maybe slowly) sync all tagged pages | |
644 | */ | |
645 | if (work->sync_mode == WB_SYNC_ALL || work->tagged_writepages) | |
646 | pages = LONG_MAX; | |
1a12d8bd WF |
647 | else { |
648 | pages = min(bdi->avg_write_bandwidth / 2, | |
649 | global_dirty_limit / DIRTY_SCOPE); | |
650 | pages = min(pages, work->nr_pages); | |
651 | pages = round_down(pages + MIN_WRITEBACK_PAGES, | |
652 | MIN_WRITEBACK_PAGES); | |
653 | } | |
d46db3d5 WF |
654 | |
655 | return pages; | |
656 | } | |
657 | ||
f11c9c5c ES |
658 | /* |
659 | * Write a portion of b_io inodes which belong to @sb. | |
edadfb10 | 660 | * |
d46db3d5 | 661 | * Return the number of pages and/or inodes written. |
f11c9c5c | 662 | */ |
d46db3d5 WF |
663 | static long writeback_sb_inodes(struct super_block *sb, |
664 | struct bdi_writeback *wb, | |
665 | struct wb_writeback_work *work) | |
1da177e4 | 666 | { |
d46db3d5 WF |
667 | struct writeback_control wbc = { |
668 | .sync_mode = work->sync_mode, | |
669 | .tagged_writepages = work->tagged_writepages, | |
670 | .for_kupdate = work->for_kupdate, | |
671 | .for_background = work->for_background, | |
7747bd4b | 672 | .for_sync = work->for_sync, |
d46db3d5 WF |
673 | .range_cyclic = work->range_cyclic, |
674 | .range_start = 0, | |
675 | .range_end = LLONG_MAX, | |
676 | }; | |
677 | unsigned long start_time = jiffies; | |
678 | long write_chunk; | |
679 | long wrote = 0; /* count both pages and inodes */ | |
680 | ||
03ba3782 | 681 | while (!list_empty(&wb->b_io)) { |
7ccf19a8 | 682 | struct inode *inode = wb_inode(wb->b_io.prev); |
edadfb10 CH |
683 | |
684 | if (inode->i_sb != sb) { | |
d46db3d5 | 685 | if (work->sb) { |
edadfb10 CH |
686 | /* |
687 | * We only want to write back data for this | |
688 | * superblock, move all inodes not belonging | |
689 | * to it back onto the dirty list. | |
690 | */ | |
f758eeab | 691 | redirty_tail(inode, wb); |
edadfb10 CH |
692 | continue; |
693 | } | |
694 | ||
695 | /* | |
696 | * The inode belongs to a different superblock. | |
697 | * Bounce back to the caller to unpin this and | |
698 | * pin the next superblock. | |
699 | */ | |
d46db3d5 | 700 | break; |
edadfb10 CH |
701 | } |
702 | ||
9843b76a | 703 | /* |
331cbdee WL |
704 | * Don't bother with new inodes or inodes being freed, first |
705 | * kind does not need periodic writeout yet, and for the latter | |
9843b76a CH |
706 | * kind writeout is handled by the freer. |
707 | */ | |
250df6ed | 708 | spin_lock(&inode->i_lock); |
9843b76a | 709 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
250df6ed | 710 | spin_unlock(&inode->i_lock); |
fcc5c222 | 711 | redirty_tail(inode, wb); |
7ef0d737 NP |
712 | continue; |
713 | } | |
cc1676d9 JK |
714 | if ((inode->i_state & I_SYNC) && wbc.sync_mode != WB_SYNC_ALL) { |
715 | /* | |
716 | * If this inode is locked for writeback and we are not | |
717 | * doing writeback-for-data-integrity, move it to | |
718 | * b_more_io so that writeback can proceed with the | |
719 | * other inodes on s_io. | |
720 | * | |
721 | * We'll have another go at writing back this inode | |
722 | * when we completed a full scan of b_io. | |
723 | */ | |
724 | spin_unlock(&inode->i_lock); | |
725 | requeue_io(inode, wb); | |
726 | trace_writeback_sb_inodes_requeue(inode); | |
727 | continue; | |
728 | } | |
f0d07b7f JK |
729 | spin_unlock(&wb->list_lock); |
730 | ||
4f8ad655 JK |
731 | /* |
732 | * We already requeued the inode if it had I_SYNC set and we | |
733 | * are doing WB_SYNC_NONE writeback. So this catches only the | |
734 | * WB_SYNC_ALL case. | |
735 | */ | |
169ebd90 JK |
736 | if (inode->i_state & I_SYNC) { |
737 | /* Wait for I_SYNC. This function drops i_lock... */ | |
738 | inode_sleep_on_writeback(inode); | |
739 | /* Inode may be gone, start again */ | |
ead188f9 | 740 | spin_lock(&wb->list_lock); |
169ebd90 JK |
741 | continue; |
742 | } | |
4f8ad655 JK |
743 | inode->i_state |= I_SYNC; |
744 | spin_unlock(&inode->i_lock); | |
169ebd90 | 745 | |
1a12d8bd | 746 | write_chunk = writeback_chunk_size(wb->bdi, work); |
d46db3d5 WF |
747 | wbc.nr_to_write = write_chunk; |
748 | wbc.pages_skipped = 0; | |
250df6ed | 749 | |
169ebd90 JK |
750 | /* |
751 | * We use I_SYNC to pin the inode in memory. While it is set | |
752 | * evict_inode() will wait so the inode cannot be freed. | |
753 | */ | |
cd8ed2a4 | 754 | __writeback_single_inode(inode, &wbc); |
250df6ed | 755 | |
d46db3d5 WF |
756 | work->nr_pages -= write_chunk - wbc.nr_to_write; |
757 | wrote += write_chunk - wbc.nr_to_write; | |
4f8ad655 JK |
758 | spin_lock(&wb->list_lock); |
759 | spin_lock(&inode->i_lock); | |
0ae45f63 | 760 | if (!(inode->i_state & I_DIRTY_ALL)) |
d46db3d5 | 761 | wrote++; |
4f8ad655 JK |
762 | requeue_inode(inode, wb, &wbc); |
763 | inode_sync_complete(inode); | |
0f1b1fd8 | 764 | spin_unlock(&inode->i_lock); |
169ebd90 | 765 | cond_resched_lock(&wb->list_lock); |
d46db3d5 WF |
766 | /* |
767 | * bail out to wb_writeback() often enough to check | |
768 | * background threshold and other termination conditions. | |
769 | */ | |
770 | if (wrote) { | |
771 | if (time_is_before_jiffies(start_time + HZ / 10UL)) | |
772 | break; | |
773 | if (work->nr_pages <= 0) | |
774 | break; | |
8bc3be27 | 775 | } |
1da177e4 | 776 | } |
d46db3d5 | 777 | return wrote; |
f11c9c5c ES |
778 | } |
779 | ||
d46db3d5 WF |
780 | static long __writeback_inodes_wb(struct bdi_writeback *wb, |
781 | struct wb_writeback_work *work) | |
f11c9c5c | 782 | { |
d46db3d5 WF |
783 | unsigned long start_time = jiffies; |
784 | long wrote = 0; | |
38f21977 | 785 | |
f11c9c5c | 786 | while (!list_empty(&wb->b_io)) { |
7ccf19a8 | 787 | struct inode *inode = wb_inode(wb->b_io.prev); |
f11c9c5c | 788 | struct super_block *sb = inode->i_sb; |
9ecc2738 | 789 | |
eb6ef3df | 790 | if (!trylock_super(sb)) { |
0e995816 | 791 | /* |
eb6ef3df | 792 | * trylock_super() may fail consistently due to |
0e995816 WF |
793 | * s_umount being grabbed by someone else. Don't use |
794 | * requeue_io() to avoid busy retrying the inode/sb. | |
795 | */ | |
796 | redirty_tail(inode, wb); | |
edadfb10 | 797 | continue; |
f11c9c5c | 798 | } |
d46db3d5 | 799 | wrote += writeback_sb_inodes(sb, wb, work); |
eb6ef3df | 800 | up_read(&sb->s_umount); |
f11c9c5c | 801 | |
d46db3d5 WF |
802 | /* refer to the same tests at the end of writeback_sb_inodes */ |
803 | if (wrote) { | |
804 | if (time_is_before_jiffies(start_time + HZ / 10UL)) | |
805 | break; | |
806 | if (work->nr_pages <= 0) | |
807 | break; | |
808 | } | |
f11c9c5c | 809 | } |
66f3b8e2 | 810 | /* Leave any unwritten inodes on b_io */ |
d46db3d5 | 811 | return wrote; |
66f3b8e2 JA |
812 | } |
813 | ||
7d9f073b | 814 | static long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages, |
0e175a18 | 815 | enum wb_reason reason) |
edadfb10 | 816 | { |
d46db3d5 WF |
817 | struct wb_writeback_work work = { |
818 | .nr_pages = nr_pages, | |
819 | .sync_mode = WB_SYNC_NONE, | |
820 | .range_cyclic = 1, | |
0e175a18 | 821 | .reason = reason, |
d46db3d5 | 822 | }; |
edadfb10 | 823 | |
f758eeab | 824 | spin_lock(&wb->list_lock); |
424b351f | 825 | if (list_empty(&wb->b_io)) |
ad4e38dd | 826 | queue_io(wb, &work); |
d46db3d5 | 827 | __writeback_inodes_wb(wb, &work); |
f758eeab | 828 | spin_unlock(&wb->list_lock); |
edadfb10 | 829 | |
d46db3d5 WF |
830 | return nr_pages - work.nr_pages; |
831 | } | |
03ba3782 | 832 | |
b00949aa | 833 | static bool over_bground_thresh(struct backing_dev_info *bdi) |
03ba3782 JA |
834 | { |
835 | unsigned long background_thresh, dirty_thresh; | |
836 | ||
16c4042f | 837 | global_dirty_limits(&background_thresh, &dirty_thresh); |
03ba3782 | 838 | |
b00949aa WF |
839 | if (global_page_state(NR_FILE_DIRTY) + |
840 | global_page_state(NR_UNSTABLE_NFS) > background_thresh) | |
841 | return true; | |
842 | ||
843 | if (bdi_stat(bdi, BDI_RECLAIMABLE) > | |
844 | bdi_dirty_limit(bdi, background_thresh)) | |
845 | return true; | |
846 | ||
847 | return false; | |
03ba3782 JA |
848 | } |
849 | ||
e98be2d5 WF |
850 | /* |
851 | * Called under wb->list_lock. If there are multiple wb per bdi, | |
852 | * only the flusher working on the first wb should do it. | |
853 | */ | |
854 | static void wb_update_bandwidth(struct bdi_writeback *wb, | |
855 | unsigned long start_time) | |
856 | { | |
af6a3113 | 857 | __bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, 0, start_time); |
e98be2d5 WF |
858 | } |
859 | ||
03ba3782 JA |
860 | /* |
861 | * Explicit flushing or periodic writeback of "old" data. | |
66f3b8e2 | 862 | * |
03ba3782 JA |
863 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
864 | * dirtying-time in the inode's address_space. So this periodic writeback code | |
865 | * just walks the superblock inode list, writing back any inodes which are | |
866 | * older than a specific point in time. | |
66f3b8e2 | 867 | * |
03ba3782 JA |
868 | * Try to run once per dirty_writeback_interval. But if a writeback event |
869 | * takes longer than a dirty_writeback_interval interval, then leave a | |
870 | * one-second gap. | |
66f3b8e2 | 871 | * |
03ba3782 JA |
872 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
873 | * all dirty pages if they are all attached to "old" mappings. | |
66f3b8e2 | 874 | */ |
c4a77a6c | 875 | static long wb_writeback(struct bdi_writeback *wb, |
83ba7b07 | 876 | struct wb_writeback_work *work) |
66f3b8e2 | 877 | { |
e98be2d5 | 878 | unsigned long wb_start = jiffies; |
d46db3d5 | 879 | long nr_pages = work->nr_pages; |
0dc83bd3 | 880 | unsigned long oldest_jif; |
a5989bdc | 881 | struct inode *inode; |
d46db3d5 | 882 | long progress; |
66f3b8e2 | 883 | |
0dc83bd3 JK |
884 | oldest_jif = jiffies; |
885 | work->older_than_this = &oldest_jif; | |
38f21977 | 886 | |
e8dfc305 | 887 | spin_lock(&wb->list_lock); |
03ba3782 JA |
888 | for (;;) { |
889 | /* | |
d3ddec76 | 890 | * Stop writeback when nr_pages has been consumed |
03ba3782 | 891 | */ |
83ba7b07 | 892 | if (work->nr_pages <= 0) |
03ba3782 | 893 | break; |
66f3b8e2 | 894 | |
aa373cf5 JK |
895 | /* |
896 | * Background writeout and kupdate-style writeback may | |
897 | * run forever. Stop them if there is other work to do | |
898 | * so that e.g. sync can proceed. They'll be restarted | |
899 | * after the other works are all done. | |
900 | */ | |
901 | if ((work->for_background || work->for_kupdate) && | |
902 | !list_empty(&wb->bdi->work_list)) | |
903 | break; | |
904 | ||
38f21977 | 905 | /* |
d3ddec76 WF |
906 | * For background writeout, stop when we are below the |
907 | * background dirty threshold | |
38f21977 | 908 | */ |
b00949aa | 909 | if (work->for_background && !over_bground_thresh(wb->bdi)) |
03ba3782 | 910 | break; |
38f21977 | 911 | |
1bc36b64 JK |
912 | /* |
913 | * Kupdate and background works are special and we want to | |
914 | * include all inodes that need writing. Livelock avoidance is | |
915 | * handled by these works yielding to any other work so we are | |
916 | * safe. | |
917 | */ | |
ba9aa839 | 918 | if (work->for_kupdate) { |
0dc83bd3 | 919 | oldest_jif = jiffies - |
ba9aa839 | 920 | msecs_to_jiffies(dirty_expire_interval * 10); |
1bc36b64 | 921 | } else if (work->for_background) |
0dc83bd3 | 922 | oldest_jif = jiffies; |
028c2dd1 | 923 | |
d46db3d5 | 924 | trace_writeback_start(wb->bdi, work); |
e8dfc305 | 925 | if (list_empty(&wb->b_io)) |
ad4e38dd | 926 | queue_io(wb, work); |
83ba7b07 | 927 | if (work->sb) |
d46db3d5 | 928 | progress = writeback_sb_inodes(work->sb, wb, work); |
edadfb10 | 929 | else |
d46db3d5 WF |
930 | progress = __writeback_inodes_wb(wb, work); |
931 | trace_writeback_written(wb->bdi, work); | |
028c2dd1 | 932 | |
e98be2d5 | 933 | wb_update_bandwidth(wb, wb_start); |
03ba3782 JA |
934 | |
935 | /* | |
e6fb6da2 WF |
936 | * Did we write something? Try for more |
937 | * | |
938 | * Dirty inodes are moved to b_io for writeback in batches. | |
939 | * The completion of the current batch does not necessarily | |
940 | * mean the overall work is done. So we keep looping as long | |
941 | * as made some progress on cleaning pages or inodes. | |
03ba3782 | 942 | */ |
d46db3d5 | 943 | if (progress) |
71fd05a8 JA |
944 | continue; |
945 | /* | |
e6fb6da2 | 946 | * No more inodes for IO, bail |
71fd05a8 | 947 | */ |
b7a2441f | 948 | if (list_empty(&wb->b_more_io)) |
03ba3782 | 949 | break; |
71fd05a8 JA |
950 | /* |
951 | * Nothing written. Wait for some inode to | |
952 | * become available for writeback. Otherwise | |
953 | * we'll just busyloop. | |
954 | */ | |
71fd05a8 | 955 | if (!list_empty(&wb->b_more_io)) { |
d46db3d5 | 956 | trace_writeback_wait(wb->bdi, work); |
7ccf19a8 | 957 | inode = wb_inode(wb->b_more_io.prev); |
250df6ed | 958 | spin_lock(&inode->i_lock); |
f0d07b7f | 959 | spin_unlock(&wb->list_lock); |
169ebd90 JK |
960 | /* This function drops i_lock... */ |
961 | inode_sleep_on_writeback(inode); | |
f0d07b7f | 962 | spin_lock(&wb->list_lock); |
03ba3782 JA |
963 | } |
964 | } | |
e8dfc305 | 965 | spin_unlock(&wb->list_lock); |
03ba3782 | 966 | |
d46db3d5 | 967 | return nr_pages - work->nr_pages; |
03ba3782 JA |
968 | } |
969 | ||
970 | /* | |
83ba7b07 | 971 | * Return the next wb_writeback_work struct that hasn't been processed yet. |
03ba3782 | 972 | */ |
83ba7b07 | 973 | static struct wb_writeback_work * |
08852b6d | 974 | get_next_work_item(struct backing_dev_info *bdi) |
03ba3782 | 975 | { |
83ba7b07 | 976 | struct wb_writeback_work *work = NULL; |
03ba3782 | 977 | |
6467716a | 978 | spin_lock_bh(&bdi->wb_lock); |
83ba7b07 CH |
979 | if (!list_empty(&bdi->work_list)) { |
980 | work = list_entry(bdi->work_list.next, | |
981 | struct wb_writeback_work, list); | |
982 | list_del_init(&work->list); | |
03ba3782 | 983 | } |
6467716a | 984 | spin_unlock_bh(&bdi->wb_lock); |
83ba7b07 | 985 | return work; |
03ba3782 JA |
986 | } |
987 | ||
cdf01dd5 LT |
988 | /* |
989 | * Add in the number of potentially dirty inodes, because each inode | |
990 | * write can dirty pagecache in the underlying blockdev. | |
991 | */ | |
992 | static unsigned long get_nr_dirty_pages(void) | |
993 | { | |
994 | return global_page_state(NR_FILE_DIRTY) + | |
995 | global_page_state(NR_UNSTABLE_NFS) + | |
996 | get_nr_dirty_inodes(); | |
997 | } | |
998 | ||
6585027a JK |
999 | static long wb_check_background_flush(struct bdi_writeback *wb) |
1000 | { | |
b00949aa | 1001 | if (over_bground_thresh(wb->bdi)) { |
6585027a JK |
1002 | |
1003 | struct wb_writeback_work work = { | |
1004 | .nr_pages = LONG_MAX, | |
1005 | .sync_mode = WB_SYNC_NONE, | |
1006 | .for_background = 1, | |
1007 | .range_cyclic = 1, | |
0e175a18 | 1008 | .reason = WB_REASON_BACKGROUND, |
6585027a JK |
1009 | }; |
1010 | ||
1011 | return wb_writeback(wb, &work); | |
1012 | } | |
1013 | ||
1014 | return 0; | |
1015 | } | |
1016 | ||
03ba3782 JA |
1017 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
1018 | { | |
1019 | unsigned long expired; | |
1020 | long nr_pages; | |
1021 | ||
69b62d01 JA |
1022 | /* |
1023 | * When set to zero, disable periodic writeback | |
1024 | */ | |
1025 | if (!dirty_writeback_interval) | |
1026 | return 0; | |
1027 | ||
03ba3782 JA |
1028 | expired = wb->last_old_flush + |
1029 | msecs_to_jiffies(dirty_writeback_interval * 10); | |
1030 | if (time_before(jiffies, expired)) | |
1031 | return 0; | |
1032 | ||
1033 | wb->last_old_flush = jiffies; | |
cdf01dd5 | 1034 | nr_pages = get_nr_dirty_pages(); |
03ba3782 | 1035 | |
c4a77a6c | 1036 | if (nr_pages) { |
83ba7b07 | 1037 | struct wb_writeback_work work = { |
c4a77a6c JA |
1038 | .nr_pages = nr_pages, |
1039 | .sync_mode = WB_SYNC_NONE, | |
1040 | .for_kupdate = 1, | |
1041 | .range_cyclic = 1, | |
0e175a18 | 1042 | .reason = WB_REASON_PERIODIC, |
c4a77a6c JA |
1043 | }; |
1044 | ||
83ba7b07 | 1045 | return wb_writeback(wb, &work); |
c4a77a6c | 1046 | } |
03ba3782 JA |
1047 | |
1048 | return 0; | |
1049 | } | |
1050 | ||
1051 | /* | |
1052 | * Retrieve work items and do the writeback they describe | |
1053 | */ | |
25d130ba | 1054 | static long wb_do_writeback(struct bdi_writeback *wb) |
03ba3782 JA |
1055 | { |
1056 | struct backing_dev_info *bdi = wb->bdi; | |
83ba7b07 | 1057 | struct wb_writeback_work *work; |
c4a77a6c | 1058 | long wrote = 0; |
03ba3782 | 1059 | |
81d73a32 | 1060 | set_bit(BDI_writeback_running, &wb->bdi->state); |
08852b6d | 1061 | while ((work = get_next_work_item(bdi)) != NULL) { |
03ba3782 | 1062 | |
455b2864 DC |
1063 | trace_writeback_exec(bdi, work); |
1064 | ||
83ba7b07 | 1065 | wrote += wb_writeback(wb, work); |
03ba3782 JA |
1066 | |
1067 | /* | |
83ba7b07 CH |
1068 | * Notify the caller of completion if this is a synchronous |
1069 | * work item, otherwise just free it. | |
03ba3782 | 1070 | */ |
83ba7b07 CH |
1071 | if (work->done) |
1072 | complete(work->done); | |
1073 | else | |
1074 | kfree(work); | |
03ba3782 JA |
1075 | } |
1076 | ||
1077 | /* | |
1078 | * Check for periodic writeback, kupdated() style | |
1079 | */ | |
1080 | wrote += wb_check_old_data_flush(wb); | |
6585027a | 1081 | wrote += wb_check_background_flush(wb); |
81d73a32 | 1082 | clear_bit(BDI_writeback_running, &wb->bdi->state); |
03ba3782 JA |
1083 | |
1084 | return wrote; | |
1085 | } | |
1086 | ||
1087 | /* | |
1088 | * Handle writeback of dirty data for the device backed by this bdi. Also | |
839a8e86 | 1089 | * reschedules periodically and does kupdated style flushing. |
03ba3782 | 1090 | */ |
839a8e86 | 1091 | void bdi_writeback_workfn(struct work_struct *work) |
03ba3782 | 1092 | { |
839a8e86 TH |
1093 | struct bdi_writeback *wb = container_of(to_delayed_work(work), |
1094 | struct bdi_writeback, dwork); | |
08243900 | 1095 | struct backing_dev_info *bdi = wb->bdi; |
03ba3782 JA |
1096 | long pages_written; |
1097 | ||
ef3b1019 | 1098 | set_worker_desc("flush-%s", dev_name(bdi->dev)); |
766f9164 | 1099 | current->flags |= PF_SWAPWRITE; |
455b2864 | 1100 | |
839a8e86 | 1101 | if (likely(!current_is_workqueue_rescuer() || |
5acda9d1 | 1102 | !test_bit(BDI_registered, &bdi->state))) { |
6467716a | 1103 | /* |
839a8e86 TH |
1104 | * The normal path. Keep writing back @bdi until its |
1105 | * work_list is empty. Note that this path is also taken | |
1106 | * if @bdi is shutting down even when we're running off the | |
1107 | * rescuer as work_list needs to be drained. | |
6467716a | 1108 | */ |
839a8e86 | 1109 | do { |
25d130ba | 1110 | pages_written = wb_do_writeback(wb); |
839a8e86 TH |
1111 | trace_writeback_pages_written(pages_written); |
1112 | } while (!list_empty(&bdi->work_list)); | |
1113 | } else { | |
1114 | /* | |
1115 | * bdi_wq can't get enough workers and we're running off | |
1116 | * the emergency worker. Don't hog it. Hopefully, 1024 is | |
1117 | * enough for efficient IO. | |
1118 | */ | |
1119 | pages_written = writeback_inodes_wb(&bdi->wb, 1024, | |
1120 | WB_REASON_FORKER_THREAD); | |
455b2864 | 1121 | trace_writeback_pages_written(pages_written); |
03ba3782 JA |
1122 | } |
1123 | ||
6ca738d6 DB |
1124 | if (!list_empty(&bdi->work_list)) |
1125 | mod_delayed_work(bdi_wq, &wb->dwork, 0); | |
1126 | else if (wb_has_dirty_io(wb) && dirty_writeback_interval) | |
1127 | bdi_wakeup_thread_delayed(bdi); | |
455b2864 | 1128 | |
839a8e86 | 1129 | current->flags &= ~PF_SWAPWRITE; |
03ba3782 JA |
1130 | } |
1131 | ||
1132 | /* | |
b8c2f347 CH |
1133 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
1134 | * the whole world. | |
03ba3782 | 1135 | */ |
0e175a18 | 1136 | void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) |
03ba3782 | 1137 | { |
b8c2f347 | 1138 | struct backing_dev_info *bdi; |
03ba3782 | 1139 | |
47df3dde JK |
1140 | if (!nr_pages) |
1141 | nr_pages = get_nr_dirty_pages(); | |
03ba3782 | 1142 | |
b8c2f347 | 1143 | rcu_read_lock(); |
cfc4ba53 | 1144 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
03ba3782 JA |
1145 | if (!bdi_has_dirty_io(bdi)) |
1146 | continue; | |
0e175a18 | 1147 | __bdi_start_writeback(bdi, nr_pages, false, reason); |
03ba3782 | 1148 | } |
cfc4ba53 | 1149 | rcu_read_unlock(); |
1da177e4 LT |
1150 | } |
1151 | ||
a2f48706 TT |
1152 | /* |
1153 | * Wake up bdi's periodically to make sure dirtytime inodes gets | |
1154 | * written back periodically. We deliberately do *not* check the | |
1155 | * b_dirtytime list in wb_has_dirty_io(), since this would cause the | |
1156 | * kernel to be constantly waking up once there are any dirtytime | |
1157 | * inodes on the system. So instead we define a separate delayed work | |
1158 | * function which gets called much more rarely. (By default, only | |
1159 | * once every 12 hours.) | |
1160 | * | |
1161 | * If there is any other write activity going on in the file system, | |
1162 | * this function won't be necessary. But if the only thing that has | |
1163 | * happened on the file system is a dirtytime inode caused by an atime | |
1164 | * update, we need this infrastructure below to make sure that inode | |
1165 | * eventually gets pushed out to disk. | |
1166 | */ | |
1167 | static void wakeup_dirtytime_writeback(struct work_struct *w); | |
1168 | static DECLARE_DELAYED_WORK(dirtytime_work, wakeup_dirtytime_writeback); | |
1169 | ||
1170 | static void wakeup_dirtytime_writeback(struct work_struct *w) | |
1171 | { | |
1172 | struct backing_dev_info *bdi; | |
1173 | ||
1174 | rcu_read_lock(); | |
1175 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { | |
1176 | if (list_empty(&bdi->wb.b_dirty_time)) | |
1177 | continue; | |
1178 | bdi_wakeup_thread(bdi); | |
1179 | } | |
1180 | rcu_read_unlock(); | |
1181 | schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); | |
1182 | } | |
1183 | ||
1184 | static int __init start_dirtytime_writeback(void) | |
1185 | { | |
1186 | schedule_delayed_work(&dirtytime_work, dirtytime_expire_interval * HZ); | |
1187 | return 0; | |
1188 | } | |
1189 | __initcall(start_dirtytime_writeback); | |
1190 | ||
1efff914 TT |
1191 | int dirtytime_interval_handler(struct ctl_table *table, int write, |
1192 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
1193 | { | |
1194 | int ret; | |
1195 | ||
1196 | ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); | |
1197 | if (ret == 0 && write) | |
1198 | mod_delayed_work(system_wq, &dirtytime_work, 0); | |
1199 | return ret; | |
1200 | } | |
1201 | ||
03ba3782 JA |
1202 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
1203 | { | |
1204 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { | |
1205 | struct dentry *dentry; | |
1206 | const char *name = "?"; | |
1207 | ||
1208 | dentry = d_find_alias(inode); | |
1209 | if (dentry) { | |
1210 | spin_lock(&dentry->d_lock); | |
1211 | name = (const char *) dentry->d_name.name; | |
1212 | } | |
1213 | printk(KERN_DEBUG | |
1214 | "%s(%d): dirtied inode %lu (%s) on %s\n", | |
1215 | current->comm, task_pid_nr(current), inode->i_ino, | |
1216 | name, inode->i_sb->s_id); | |
1217 | if (dentry) { | |
1218 | spin_unlock(&dentry->d_lock); | |
1219 | dput(dentry); | |
1220 | } | |
1221 | } | |
1222 | } | |
1223 | ||
1224 | /** | |
1225 | * __mark_inode_dirty - internal function | |
1226 | * @inode: inode to mark | |
1227 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) | |
1228 | * Mark an inode as dirty. Callers should use mark_inode_dirty or | |
1229 | * mark_inode_dirty_sync. | |
1da177e4 | 1230 | * |
03ba3782 JA |
1231 | * Put the inode on the super block's dirty list. |
1232 | * | |
1233 | * CAREFUL! We mark it dirty unconditionally, but move it onto the | |
1234 | * dirty list only if it is hashed or if it refers to a blockdev. | |
1235 | * If it was not hashed, it will never be added to the dirty list | |
1236 | * even if it is later hashed, as it will have been marked dirty already. | |
1237 | * | |
1238 | * In short, make sure you hash any inodes _before_ you start marking | |
1239 | * them dirty. | |
1da177e4 | 1240 | * |
03ba3782 JA |
1241 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
1242 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of | |
1243 | * the kernel-internal blockdev inode represents the dirtying time of the | |
1244 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use | |
1245 | * page->mapping->host, so the page-dirtying time is recorded in the internal | |
1246 | * blockdev inode. | |
1da177e4 | 1247 | */ |
0ae45f63 | 1248 | #define I_DIRTY_INODE (I_DIRTY_SYNC | I_DIRTY_DATASYNC) |
03ba3782 | 1249 | void __mark_inode_dirty(struct inode *inode, int flags) |
1da177e4 | 1250 | { |
03ba3782 | 1251 | struct super_block *sb = inode->i_sb; |
253c34e9 | 1252 | struct backing_dev_info *bdi = NULL; |
0ae45f63 TT |
1253 | int dirtytime; |
1254 | ||
1255 | trace_writeback_mark_inode_dirty(inode, flags); | |
1da177e4 | 1256 | |
03ba3782 JA |
1257 | /* |
1258 | * Don't do this for I_DIRTY_PAGES - that doesn't actually | |
1259 | * dirty the inode itself | |
1260 | */ | |
0ae45f63 | 1261 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC | I_DIRTY_TIME)) { |
9fb0a7da TH |
1262 | trace_writeback_dirty_inode_start(inode, flags); |
1263 | ||
03ba3782 | 1264 | if (sb->s_op->dirty_inode) |
aa385729 | 1265 | sb->s_op->dirty_inode(inode, flags); |
9fb0a7da TH |
1266 | |
1267 | trace_writeback_dirty_inode(inode, flags); | |
03ba3782 | 1268 | } |
0ae45f63 TT |
1269 | if (flags & I_DIRTY_INODE) |
1270 | flags &= ~I_DIRTY_TIME; | |
1271 | dirtytime = flags & I_DIRTY_TIME; | |
03ba3782 JA |
1272 | |
1273 | /* | |
9c6ac78e TH |
1274 | * Paired with smp_mb() in __writeback_single_inode() for the |
1275 | * following lockless i_state test. See there for details. | |
03ba3782 JA |
1276 | */ |
1277 | smp_mb(); | |
1278 | ||
0ae45f63 TT |
1279 | if (((inode->i_state & flags) == flags) || |
1280 | (dirtytime && (inode->i_state & I_DIRTY_INODE))) | |
03ba3782 JA |
1281 | return; |
1282 | ||
1283 | if (unlikely(block_dump)) | |
1284 | block_dump___mark_inode_dirty(inode); | |
1285 | ||
250df6ed | 1286 | spin_lock(&inode->i_lock); |
0ae45f63 TT |
1287 | if (dirtytime && (inode->i_state & I_DIRTY_INODE)) |
1288 | goto out_unlock_inode; | |
03ba3782 JA |
1289 | if ((inode->i_state & flags) != flags) { |
1290 | const int was_dirty = inode->i_state & I_DIRTY; | |
1291 | ||
0ae45f63 TT |
1292 | if (flags & I_DIRTY_INODE) |
1293 | inode->i_state &= ~I_DIRTY_TIME; | |
03ba3782 JA |
1294 | inode->i_state |= flags; |
1295 | ||
1296 | /* | |
1297 | * If the inode is being synced, just update its dirty state. | |
1298 | * The unlocker will place the inode on the appropriate | |
1299 | * superblock list, based upon its state. | |
1300 | */ | |
1301 | if (inode->i_state & I_SYNC) | |
250df6ed | 1302 | goto out_unlock_inode; |
03ba3782 JA |
1303 | |
1304 | /* | |
1305 | * Only add valid (hashed) inodes to the superblock's | |
1306 | * dirty list. Add blockdev inodes as well. | |
1307 | */ | |
1308 | if (!S_ISBLK(inode->i_mode)) { | |
1d3382cb | 1309 | if (inode_unhashed(inode)) |
250df6ed | 1310 | goto out_unlock_inode; |
03ba3782 | 1311 | } |
a4ffdde6 | 1312 | if (inode->i_state & I_FREEING) |
250df6ed | 1313 | goto out_unlock_inode; |
03ba3782 JA |
1314 | |
1315 | /* | |
1316 | * If the inode was already on b_dirty/b_io/b_more_io, don't | |
1317 | * reposition it (that would break b_dirty time-ordering). | |
1318 | */ | |
1319 | if (!was_dirty) { | |
a66979ab | 1320 | bool wakeup_bdi = false; |
253c34e9 AB |
1321 | bdi = inode_to_bdi(inode); |
1322 | ||
146d7009 JB |
1323 | spin_unlock(&inode->i_lock); |
1324 | spin_lock(&bdi->wb.list_lock); | |
253c34e9 AB |
1325 | if (bdi_cap_writeback_dirty(bdi)) { |
1326 | WARN(!test_bit(BDI_registered, &bdi->state), | |
1327 | "bdi-%s not registered\n", bdi->name); | |
1328 | ||
1329 | /* | |
1330 | * If this is the first dirty inode for this | |
1331 | * bdi, we have to wake-up the corresponding | |
1332 | * bdi thread to make sure background | |
1333 | * write-back happens later. | |
1334 | */ | |
1335 | if (!wb_has_dirty_io(&bdi->wb)) | |
1336 | wakeup_bdi = true; | |
500b067c | 1337 | } |
03ba3782 JA |
1338 | |
1339 | inode->dirtied_when = jiffies; | |
a2f48706 TT |
1340 | if (dirtytime) |
1341 | inode->dirtied_time_when = jiffies; | |
1342 | if (inode->i_state & (I_DIRTY_INODE | I_DIRTY_PAGES)) | |
1343 | list_move(&inode->i_wb_list, &bdi->wb.b_dirty); | |
1344 | else | |
1345 | list_move(&inode->i_wb_list, | |
1346 | &bdi->wb.b_dirty_time); | |
f758eeab | 1347 | spin_unlock(&bdi->wb.list_lock); |
0ae45f63 | 1348 | trace_writeback_dirty_inode_enqueue(inode); |
a66979ab DC |
1349 | |
1350 | if (wakeup_bdi) | |
1351 | bdi_wakeup_thread_delayed(bdi); | |
1352 | return; | |
1da177e4 | 1353 | } |
1da177e4 | 1354 | } |
250df6ed DC |
1355 | out_unlock_inode: |
1356 | spin_unlock(&inode->i_lock); | |
253c34e9 | 1357 | |
03ba3782 JA |
1358 | } |
1359 | EXPORT_SYMBOL(__mark_inode_dirty); | |
1360 | ||
b6e51316 | 1361 | static void wait_sb_inodes(struct super_block *sb) |
03ba3782 JA |
1362 | { |
1363 | struct inode *inode, *old_inode = NULL; | |
1364 | ||
1365 | /* | |
1366 | * We need to be protected against the filesystem going from | |
1367 | * r/o to r/w or vice versa. | |
1368 | */ | |
b6e51316 | 1369 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
03ba3782 | 1370 | |
55fa6091 | 1371 | spin_lock(&inode_sb_list_lock); |
03ba3782 JA |
1372 | |
1373 | /* | |
1374 | * Data integrity sync. Must wait for all pages under writeback, | |
1375 | * because there may have been pages dirtied before our sync | |
1376 | * call, but which had writeout started before we write it out. | |
1377 | * In which case, the inode may not be on the dirty list, but | |
1378 | * we still have to wait for that writeout. | |
1379 | */ | |
b6e51316 | 1380 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
250df6ed | 1381 | struct address_space *mapping = inode->i_mapping; |
03ba3782 | 1382 | |
250df6ed DC |
1383 | spin_lock(&inode->i_lock); |
1384 | if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) || | |
1385 | (mapping->nrpages == 0)) { | |
1386 | spin_unlock(&inode->i_lock); | |
03ba3782 | 1387 | continue; |
250df6ed | 1388 | } |
03ba3782 | 1389 | __iget(inode); |
250df6ed | 1390 | spin_unlock(&inode->i_lock); |
55fa6091 DC |
1391 | spin_unlock(&inode_sb_list_lock); |
1392 | ||
03ba3782 | 1393 | /* |
55fa6091 DC |
1394 | * We hold a reference to 'inode' so it couldn't have been |
1395 | * removed from s_inodes list while we dropped the | |
1396 | * inode_sb_list_lock. We cannot iput the inode now as we can | |
1397 | * be holding the last reference and we cannot iput it under | |
1398 | * inode_sb_list_lock. So we keep the reference and iput it | |
1399 | * later. | |
03ba3782 JA |
1400 | */ |
1401 | iput(old_inode); | |
1402 | old_inode = inode; | |
1403 | ||
1404 | filemap_fdatawait(mapping); | |
1405 | ||
1406 | cond_resched(); | |
1407 | ||
55fa6091 | 1408 | spin_lock(&inode_sb_list_lock); |
03ba3782 | 1409 | } |
55fa6091 | 1410 | spin_unlock(&inode_sb_list_lock); |
03ba3782 | 1411 | iput(old_inode); |
1da177e4 LT |
1412 | } |
1413 | ||
d8a8559c | 1414 | /** |
3259f8be | 1415 | * writeback_inodes_sb_nr - writeback dirty inodes from given super_block |
d8a8559c | 1416 | * @sb: the superblock |
3259f8be | 1417 | * @nr: the number of pages to write |
786228ab | 1418 | * @reason: reason why some writeback work initiated |
1da177e4 | 1419 | * |
d8a8559c JA |
1420 | * Start writeback on some inodes on this super_block. No guarantees are made |
1421 | * on how many (if any) will be written, and this function does not wait | |
3259f8be | 1422 | * for IO completion of submitted IO. |
1da177e4 | 1423 | */ |
0e175a18 CW |
1424 | void writeback_inodes_sb_nr(struct super_block *sb, |
1425 | unsigned long nr, | |
1426 | enum wb_reason reason) | |
1da177e4 | 1427 | { |
83ba7b07 CH |
1428 | DECLARE_COMPLETION_ONSTACK(done); |
1429 | struct wb_writeback_work work = { | |
6e6938b6 WF |
1430 | .sb = sb, |
1431 | .sync_mode = WB_SYNC_NONE, | |
1432 | .tagged_writepages = 1, | |
1433 | .done = &done, | |
1434 | .nr_pages = nr, | |
0e175a18 | 1435 | .reason = reason, |
3c4d7165 | 1436 | }; |
d8a8559c | 1437 | |
6eedc701 JK |
1438 | if (sb->s_bdi == &noop_backing_dev_info) |
1439 | return; | |
cf37e972 | 1440 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
83ba7b07 CH |
1441 | bdi_queue_work(sb->s_bdi, &work); |
1442 | wait_for_completion(&done); | |
e913fc82 | 1443 | } |
3259f8be CM |
1444 | EXPORT_SYMBOL(writeback_inodes_sb_nr); |
1445 | ||
1446 | /** | |
1447 | * writeback_inodes_sb - writeback dirty inodes from given super_block | |
1448 | * @sb: the superblock | |
786228ab | 1449 | * @reason: reason why some writeback work was initiated |
3259f8be CM |
1450 | * |
1451 | * Start writeback on some inodes on this super_block. No guarantees are made | |
1452 | * on how many (if any) will be written, and this function does not wait | |
1453 | * for IO completion of submitted IO. | |
1454 | */ | |
0e175a18 | 1455 | void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
3259f8be | 1456 | { |
0e175a18 | 1457 | return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
3259f8be | 1458 | } |
0e3c9a22 | 1459 | EXPORT_SYMBOL(writeback_inodes_sb); |
e913fc82 | 1460 | |
17bd55d0 | 1461 | /** |
10ee27a0 | 1462 | * try_to_writeback_inodes_sb_nr - try to start writeback if none underway |
17bd55d0 | 1463 | * @sb: the superblock |
10ee27a0 MX |
1464 | * @nr: the number of pages to write |
1465 | * @reason: the reason of writeback | |
17bd55d0 | 1466 | * |
10ee27a0 | 1467 | * Invoke writeback_inodes_sb_nr if no writeback is currently underway. |
17bd55d0 ES |
1468 | * Returns 1 if writeback was started, 0 if not. |
1469 | */ | |
10ee27a0 MX |
1470 | int try_to_writeback_inodes_sb_nr(struct super_block *sb, |
1471 | unsigned long nr, | |
1472 | enum wb_reason reason) | |
17bd55d0 | 1473 | { |
10ee27a0 | 1474 | if (writeback_in_progress(sb->s_bdi)) |
17bd55d0 | 1475 | return 1; |
10ee27a0 MX |
1476 | |
1477 | if (!down_read_trylock(&sb->s_umount)) | |
17bd55d0 | 1478 | return 0; |
10ee27a0 MX |
1479 | |
1480 | writeback_inodes_sb_nr(sb, nr, reason); | |
1481 | up_read(&sb->s_umount); | |
1482 | return 1; | |
17bd55d0 | 1483 | } |
10ee27a0 | 1484 | EXPORT_SYMBOL(try_to_writeback_inodes_sb_nr); |
17bd55d0 | 1485 | |
3259f8be | 1486 | /** |
10ee27a0 | 1487 | * try_to_writeback_inodes_sb - try to start writeback if none underway |
3259f8be | 1488 | * @sb: the superblock |
786228ab | 1489 | * @reason: reason why some writeback work was initiated |
3259f8be | 1490 | * |
10ee27a0 | 1491 | * Implement by try_to_writeback_inodes_sb_nr() |
3259f8be CM |
1492 | * Returns 1 if writeback was started, 0 if not. |
1493 | */ | |
10ee27a0 | 1494 | int try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
3259f8be | 1495 | { |
10ee27a0 | 1496 | return try_to_writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
3259f8be | 1497 | } |
10ee27a0 | 1498 | EXPORT_SYMBOL(try_to_writeback_inodes_sb); |
3259f8be | 1499 | |
d8a8559c JA |
1500 | /** |
1501 | * sync_inodes_sb - sync sb inode pages | |
0dc83bd3 | 1502 | * @sb: the superblock |
d8a8559c JA |
1503 | * |
1504 | * This function writes and waits on any dirty inode belonging to this | |
0dc83bd3 | 1505 | * super_block. |
d8a8559c | 1506 | */ |
0dc83bd3 | 1507 | void sync_inodes_sb(struct super_block *sb) |
d8a8559c | 1508 | { |
83ba7b07 CH |
1509 | DECLARE_COMPLETION_ONSTACK(done); |
1510 | struct wb_writeback_work work = { | |
3c4d7165 CH |
1511 | .sb = sb, |
1512 | .sync_mode = WB_SYNC_ALL, | |
1513 | .nr_pages = LONG_MAX, | |
1514 | .range_cyclic = 0, | |
83ba7b07 | 1515 | .done = &done, |
0e175a18 | 1516 | .reason = WB_REASON_SYNC, |
7747bd4b | 1517 | .for_sync = 1, |
3c4d7165 CH |
1518 | }; |
1519 | ||
6eedc701 JK |
1520 | /* Nothing to do? */ |
1521 | if (sb->s_bdi == &noop_backing_dev_info) | |
1522 | return; | |
cf37e972 CH |
1523 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
1524 | ||
83ba7b07 CH |
1525 | bdi_queue_work(sb->s_bdi, &work); |
1526 | wait_for_completion(&done); | |
1527 | ||
b6e51316 | 1528 | wait_sb_inodes(sb); |
1da177e4 | 1529 | } |
d8a8559c | 1530 | EXPORT_SYMBOL(sync_inodes_sb); |
1da177e4 | 1531 | |
1da177e4 | 1532 | /** |
7f04c26d AA |
1533 | * write_inode_now - write an inode to disk |
1534 | * @inode: inode to write to disk | |
1535 | * @sync: whether the write should be synchronous or not | |
1536 | * | |
1537 | * This function commits an inode to disk immediately if it is dirty. This is | |
1538 | * primarily needed by knfsd. | |
1da177e4 | 1539 | * |
7f04c26d | 1540 | * The caller must either have a ref on the inode or must have set I_WILL_FREE. |
1da177e4 | 1541 | */ |
1da177e4 LT |
1542 | int write_inode_now(struct inode *inode, int sync) |
1543 | { | |
f758eeab | 1544 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
1da177e4 LT |
1545 | struct writeback_control wbc = { |
1546 | .nr_to_write = LONG_MAX, | |
18914b18 | 1547 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
111ebb6e OH |
1548 | .range_start = 0, |
1549 | .range_end = LLONG_MAX, | |
1da177e4 LT |
1550 | }; |
1551 | ||
1552 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) | |
49364ce2 | 1553 | wbc.nr_to_write = 0; |
1da177e4 LT |
1554 | |
1555 | might_sleep(); | |
4f8ad655 | 1556 | return writeback_single_inode(inode, wb, &wbc); |
1da177e4 LT |
1557 | } |
1558 | EXPORT_SYMBOL(write_inode_now); | |
1559 | ||
1560 | /** | |
1561 | * sync_inode - write an inode and its pages to disk. | |
1562 | * @inode: the inode to sync | |
1563 | * @wbc: controls the writeback mode | |
1564 | * | |
1565 | * sync_inode() will write an inode and its pages to disk. It will also | |
1566 | * correctly update the inode on its superblock's dirty inode lists and will | |
1567 | * update inode->i_state. | |
1568 | * | |
1569 | * The caller must have a ref on the inode. | |
1570 | */ | |
1571 | int sync_inode(struct inode *inode, struct writeback_control *wbc) | |
1572 | { | |
4f8ad655 | 1573 | return writeback_single_inode(inode, &inode_to_bdi(inode)->wb, wbc); |
1da177e4 LT |
1574 | } |
1575 | EXPORT_SYMBOL(sync_inode); | |
c3765016 CH |
1576 | |
1577 | /** | |
c691b9d9 | 1578 | * sync_inode_metadata - write an inode to disk |
c3765016 CH |
1579 | * @inode: the inode to sync |
1580 | * @wait: wait for I/O to complete. | |
1581 | * | |
c691b9d9 | 1582 | * Write an inode to disk and adjust its dirty state after completion. |
c3765016 CH |
1583 | * |
1584 | * Note: only writes the actual inode, no associated data or other metadata. | |
1585 | */ | |
1586 | int sync_inode_metadata(struct inode *inode, int wait) | |
1587 | { | |
1588 | struct writeback_control wbc = { | |
1589 | .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE, | |
1590 | .nr_to_write = 0, /* metadata-only */ | |
1591 | }; | |
1592 | ||
1593 | return sync_inode(inode, &wbc); | |
1594 | } | |
1595 | EXPORT_SYMBOL(sync_inode_metadata); |