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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 | * |
11 | * 10Apr2002 Andrew Morton |
12 | * Split out of fs/inode.c |
13 | * Additions for address_space-based writeback |
14 | */ |
15 | |
16 | #include <linux/kernel.h> |
17 | #include <linux/module.h> |
18 | #include <linux/spinlock.h> |
19 | #include <linux/slab.h> |
20 | #include <linux/sched.h> |
21 | #include <linux/fs.h> |
22 | #include <linux/mm.h> |
23 | #include <linux/kthread.h> |
24 | #include <linux/freezer.h> |
25 | #include <linux/writeback.h> |
26 | #include <linux/blkdev.h> |
27 | #include <linux/backing-dev.h> |
28 | #include <linux/buffer_head.h> |
29 | #include "internal.h" |
30 | |
31 | #define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info) |
32 | |
33 | /* |
34 | * We don't actually have pdflush, but this one is exported though /proc... |
35 | */ |
36 | int nr_pdflush_threads; |
37 | |
38 | /* |
39 | * Passed into wb_writeback(), essentially a subset of writeback_control |
40 | */ |
41 | struct wb_writeback_args { |
42 | long nr_pages; |
43 | struct super_block *sb; |
44 | enum writeback_sync_modes sync_mode; |
45 | int for_kupdate:1; |
46 | int range_cyclic:1; |
47 | int for_background:1; |
48 | }; |
49 | |
50 | /* |
51 | * Work items for the bdi_writeback threads |
52 | */ |
53 | struct bdi_work { |
54 | struct list_head list; /* pending work list */ |
55 | struct rcu_head rcu_head; /* for RCU free/clear of work */ |
56 | |
57 | unsigned long seen; /* threads that have seen this work */ |
58 | atomic_t pending; /* number of threads still to do work */ |
59 | |
60 | struct wb_writeback_args args; /* writeback arguments */ |
61 | |
62 | unsigned long state; /* flag bits, see WS_* */ |
63 | }; |
64 | |
65 | enum { |
66 | WS_USED_B = 0, |
67 | WS_ONSTACK_B, |
68 | }; |
69 | |
70 | #define WS_USED (1 << WS_USED_B) |
71 | #define WS_ONSTACK (1 << WS_ONSTACK_B) |
72 | |
73 | static inline bool bdi_work_on_stack(struct bdi_work *work) |
74 | { |
75 | return test_bit(WS_ONSTACK_B, &work->state); |
76 | } |
77 | |
78 | static inline void bdi_work_init(struct bdi_work *work, |
79 | struct wb_writeback_args *args) |
80 | { |
81 | INIT_RCU_HEAD(&work->rcu_head); |
82 | work->args = *args; |
83 | work->state = WS_USED; |
84 | } |
85 | |
86 | /** |
87 | * writeback_in_progress - determine whether there is writeback in progress |
88 | * @bdi: the device's backing_dev_info structure. |
89 | * |
90 | * Determine whether there is writeback waiting to be handled against a |
91 | * backing device. |
92 | */ |
93 | int writeback_in_progress(struct backing_dev_info *bdi) |
94 | { |
95 | return !list_empty(&bdi->work_list); |
96 | } |
97 | |
98 | static void bdi_work_clear(struct bdi_work *work) |
99 | { |
100 | clear_bit(WS_USED_B, &work->state); |
101 | smp_mb__after_clear_bit(); |
102 | /* |
103 | * work can have disappeared at this point. bit waitq functions |
104 | * should be able to tolerate this, provided bdi_sched_wait does |
105 | * not dereference it's pointer argument. |
106 | */ |
107 | wake_up_bit(&work->state, WS_USED_B); |
108 | } |
109 | |
110 | static void bdi_work_free(struct rcu_head *head) |
111 | { |
112 | struct bdi_work *work = container_of(head, struct bdi_work, rcu_head); |
113 | |
114 | if (!bdi_work_on_stack(work)) |
115 | kfree(work); |
116 | else |
117 | bdi_work_clear(work); |
118 | } |
119 | |
120 | static void wb_work_complete(struct bdi_work *work) |
121 | { |
122 | const enum writeback_sync_modes sync_mode = work->args.sync_mode; |
123 | int onstack = bdi_work_on_stack(work); |
124 | |
125 | /* |
126 | * For allocated work, we can clear the done/seen bit right here. |
127 | * For on-stack work, we need to postpone both the clear and free |
128 | * to after the RCU grace period, since the stack could be invalidated |
129 | * as soon as bdi_work_clear() has done the wakeup. |
130 | */ |
131 | if (!onstack) |
132 | bdi_work_clear(work); |
133 | if (sync_mode == WB_SYNC_NONE || onstack) |
134 | call_rcu(&work->rcu_head, bdi_work_free); |
135 | } |
136 | |
137 | static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) |
138 | { |
139 | /* |
140 | * The caller has retrieved the work arguments from this work, |
141 | * drop our reference. If this is the last ref, delete and free it |
142 | */ |
143 | if (atomic_dec_and_test(&work->pending)) { |
144 | struct backing_dev_info *bdi = wb->bdi; |
145 | |
146 | spin_lock(&bdi->wb_lock); |
147 | list_del_rcu(&work->list); |
148 | spin_unlock(&bdi->wb_lock); |
149 | |
150 | wb_work_complete(work); |
151 | } |
152 | } |
153 | |
154 | static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work) |
155 | { |
156 | work->seen = bdi->wb_mask; |
157 | BUG_ON(!work->seen); |
158 | atomic_set(&work->pending, bdi->wb_cnt); |
159 | BUG_ON(!bdi->wb_cnt); |
160 | |
161 | /* |
162 | * list_add_tail_rcu() contains the necessary barriers to |
163 | * make sure the above stores are seen before the item is |
164 | * noticed on the list |
165 | */ |
166 | spin_lock(&bdi->wb_lock); |
167 | list_add_tail_rcu(&work->list, &bdi->work_list); |
168 | spin_unlock(&bdi->wb_lock); |
169 | |
170 | /* |
171 | * If the default thread isn't there, make sure we add it. When |
172 | * it gets created and wakes up, we'll run this work. |
173 | */ |
174 | if (unlikely(list_empty_careful(&bdi->wb_list))) |
175 | wake_up_process(default_backing_dev_info.wb.task); |
176 | else { |
177 | struct bdi_writeback *wb = &bdi->wb; |
178 | |
179 | if (wb->task) |
180 | wake_up_process(wb->task); |
181 | } |
182 | } |
183 | |
184 | /* |
185 | * Used for on-stack allocated work items. The caller needs to wait until |
186 | * the wb threads have acked the work before it's safe to continue. |
187 | */ |
188 | static void bdi_wait_on_work_clear(struct bdi_work *work) |
189 | { |
190 | wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait, |
191 | TASK_UNINTERRUPTIBLE); |
192 | } |
193 | |
194 | static void bdi_alloc_queue_work(struct backing_dev_info *bdi, |
195 | struct wb_writeback_args *args) |
196 | { |
197 | struct bdi_work *work; |
198 | |
199 | /* |
200 | * This is WB_SYNC_NONE writeback, so if allocation fails just |
201 | * wakeup the thread for old dirty data writeback |
202 | */ |
203 | work = kmalloc(sizeof(*work), GFP_ATOMIC); |
204 | if (work) { |
205 | bdi_work_init(work, args); |
206 | bdi_queue_work(bdi, work); |
207 | } else { |
208 | struct bdi_writeback *wb = &bdi->wb; |
209 | |
210 | if (wb->task) |
211 | wake_up_process(wb->task); |
212 | } |
213 | } |
214 | |
215 | /** |
216 | * bdi_sync_writeback - start and wait for writeback |
217 | * @bdi: the backing device to write from |
218 | * @sb: write inodes from this super_block |
219 | * |
220 | * Description: |
221 | * This does WB_SYNC_ALL data integrity writeback and waits for the |
222 | * IO to complete. Callers must hold the sb s_umount semaphore for |
223 | * reading, to avoid having the super disappear before we are done. |
224 | */ |
225 | static void bdi_sync_writeback(struct backing_dev_info *bdi, |
226 | struct super_block *sb) |
227 | { |
228 | struct wb_writeback_args args = { |
229 | .sb = sb, |
230 | .sync_mode = WB_SYNC_ALL, |
231 | .nr_pages = LONG_MAX, |
232 | .range_cyclic = 0, |
233 | }; |
234 | struct bdi_work work; |
235 | |
236 | bdi_work_init(&work, &args); |
237 | work.state |= WS_ONSTACK; |
238 | |
239 | bdi_queue_work(bdi, &work); |
240 | bdi_wait_on_work_clear(&work); |
241 | } |
242 | |
243 | /** |
244 | * bdi_start_writeback - start writeback |
245 | * @bdi: the backing device to write from |
246 | * @sb: write inodes from this super_block |
247 | * @nr_pages: the number of pages to write |
248 | * |
249 | * Description: |
250 | * This does WB_SYNC_NONE opportunistic writeback. The IO is only |
251 | * started when this function returns, we make no guarentees on |
252 | * completion. Caller need not hold sb s_umount semaphore. |
253 | * |
254 | */ |
255 | void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, |
256 | long nr_pages) |
257 | { |
258 | struct wb_writeback_args args = { |
259 | .sb = sb, |
260 | .sync_mode = WB_SYNC_NONE, |
261 | .nr_pages = nr_pages, |
262 | .range_cyclic = 1, |
263 | }; |
264 | |
265 | /* |
266 | * We treat @nr_pages=0 as the special case to do background writeback, |
267 | * ie. to sync pages until the background dirty threshold is reached. |
268 | */ |
269 | if (!nr_pages) { |
270 | args.nr_pages = LONG_MAX; |
271 | args.for_background = 1; |
272 | } |
273 | |
274 | bdi_alloc_queue_work(bdi, &args); |
275 | } |
276 | |
277 | /* |
278 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the |
279 | * furthest end of its superblock's dirty-inode list. |
280 | * |
281 | * Before stamping the inode's ->dirtied_when, we check to see whether it is |
282 | * already the most-recently-dirtied inode on the b_dirty list. If that is |
283 | * the case then the inode must have been redirtied while it was being written |
284 | * out and we don't reset its dirtied_when. |
285 | */ |
286 | static void redirty_tail(struct inode *inode) |
287 | { |
288 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
289 | |
290 | if (!list_empty(&wb->b_dirty)) { |
291 | struct inode *tail; |
292 | |
293 | tail = list_entry(wb->b_dirty.next, struct inode, i_list); |
294 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
295 | inode->dirtied_when = jiffies; |
296 | } |
297 | list_move(&inode->i_list, &wb->b_dirty); |
298 | } |
299 | |
300 | /* |
301 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
302 | */ |
303 | static void requeue_io(struct inode *inode) |
304 | { |
305 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
306 | |
307 | list_move(&inode->i_list, &wb->b_more_io); |
308 | } |
309 | |
310 | static void inode_sync_complete(struct inode *inode) |
311 | { |
312 | /* |
313 | * Prevent speculative execution through spin_unlock(&inode_lock); |
314 | */ |
315 | smp_mb(); |
316 | wake_up_bit(&inode->i_state, __I_SYNC); |
317 | } |
318 | |
319 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
320 | { |
321 | bool ret = time_after(inode->dirtied_when, t); |
322 | #ifndef CONFIG_64BIT |
323 | /* |
324 | * For inodes being constantly redirtied, dirtied_when can get stuck. |
325 | * It _appears_ to be in the future, but is actually in distant past. |
326 | * This test is necessary to prevent such wrapped-around relative times |
327 | * from permanently stopping the whole bdi writeback. |
328 | */ |
329 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); |
330 | #endif |
331 | return ret; |
332 | } |
333 | |
334 | /* |
335 | * Move expired dirty inodes from @delaying_queue to @dispatch_queue. |
336 | */ |
337 | static void move_expired_inodes(struct list_head *delaying_queue, |
338 | struct list_head *dispatch_queue, |
339 | unsigned long *older_than_this) |
340 | { |
341 | LIST_HEAD(tmp); |
342 | struct list_head *pos, *node; |
343 | struct super_block *sb = NULL; |
344 | struct inode *inode; |
345 | int do_sb_sort = 0; |
346 | |
347 | while (!list_empty(delaying_queue)) { |
348 | inode = list_entry(delaying_queue->prev, struct inode, i_list); |
349 | if (older_than_this && |
350 | inode_dirtied_after(inode, *older_than_this)) |
351 | break; |
352 | if (sb && sb != inode->i_sb) |
353 | do_sb_sort = 1; |
354 | sb = inode->i_sb; |
355 | list_move(&inode->i_list, &tmp); |
356 | } |
357 | |
358 | /* just one sb in list, splice to dispatch_queue and we're done */ |
359 | if (!do_sb_sort) { |
360 | list_splice(&tmp, dispatch_queue); |
361 | return; |
362 | } |
363 | |
364 | /* Move inodes from one superblock together */ |
365 | while (!list_empty(&tmp)) { |
366 | inode = list_entry(tmp.prev, struct inode, i_list); |
367 | sb = inode->i_sb; |
368 | list_for_each_prev_safe(pos, node, &tmp) { |
369 | inode = list_entry(pos, struct inode, i_list); |
370 | if (inode->i_sb == sb) |
371 | list_move(&inode->i_list, dispatch_queue); |
372 | } |
373 | } |
374 | } |
375 | |
376 | /* |
377 | * Queue all expired dirty inodes for io, eldest first. |
378 | */ |
379 | static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this) |
380 | { |
381 | list_splice_init(&wb->b_more_io, wb->b_io.prev); |
382 | move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); |
383 | } |
384 | |
385 | static int write_inode(struct inode *inode, struct writeback_control *wbc) |
386 | { |
387 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) |
388 | return inode->i_sb->s_op->write_inode(inode, wbc); |
389 | return 0; |
390 | } |
391 | |
392 | /* |
393 | * Wait for writeback on an inode to complete. |
394 | */ |
395 | static void inode_wait_for_writeback(struct inode *inode) |
396 | { |
397 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); |
398 | wait_queue_head_t *wqh; |
399 | |
400 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
401 | do { |
402 | spin_unlock(&inode_lock); |
403 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
404 | spin_lock(&inode_lock); |
405 | } while (inode->i_state & I_SYNC); |
406 | } |
407 | |
408 | /* |
409 | * Write out an inode's dirty pages. Called under inode_lock. Either the |
410 | * caller has ref on the inode (either via __iget or via syscall against an fd) |
411 | * or the inode has I_WILL_FREE set (via generic_forget_inode) |
412 | * |
413 | * If `wait' is set, wait on the writeout. |
414 | * |
415 | * The whole writeout design is quite complex and fragile. We want to avoid |
416 | * starvation of particular inodes when others are being redirtied, prevent |
417 | * livelocks, etc. |
418 | * |
419 | * Called under inode_lock. |
420 | */ |
421 | static int |
422 | writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
423 | { |
424 | struct address_space *mapping = inode->i_mapping; |
425 | unsigned dirty; |
426 | int ret; |
427 | |
428 | if (!atomic_read(&inode->i_count)) |
429 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); |
430 | else |
431 | WARN_ON(inode->i_state & I_WILL_FREE); |
432 | |
433 | if (inode->i_state & I_SYNC) { |
434 | /* |
435 | * If this inode is locked for writeback and we are not doing |
436 | * writeback-for-data-integrity, move it to b_more_io so that |
437 | * writeback can proceed with the other inodes on s_io. |
438 | * |
439 | * We'll have another go at writing back this inode when we |
440 | * completed a full scan of b_io. |
441 | */ |
442 | if (wbc->sync_mode != WB_SYNC_ALL) { |
443 | requeue_io(inode); |
444 | return 0; |
445 | } |
446 | |
447 | /* |
448 | * It's a data-integrity sync. We must wait. |
449 | */ |
450 | inode_wait_for_writeback(inode); |
451 | } |
452 | |
453 | BUG_ON(inode->i_state & I_SYNC); |
454 | |
455 | /* Set I_SYNC, reset I_DIRTY */ |
456 | dirty = inode->i_state & I_DIRTY; |
457 | inode->i_state |= I_SYNC; |
458 | inode->i_state &= ~I_DIRTY; |
459 | |
460 | spin_unlock(&inode_lock); |
461 | |
462 | ret = do_writepages(mapping, wbc); |
463 | |
464 | /* |
465 | * Make sure to wait on the data before writing out the metadata. |
466 | * This is important for filesystems that modify metadata on data |
467 | * I/O completion. |
468 | */ |
469 | if (wbc->sync_mode == WB_SYNC_ALL) { |
470 | int err = filemap_fdatawait(mapping); |
471 | if (ret == 0) |
472 | ret = err; |
473 | } |
474 | |
475 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
476 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
477 | int err = write_inode(inode, wbc); |
478 | if (ret == 0) |
479 | ret = err; |
480 | } |
481 | |
482 | spin_lock(&inode_lock); |
483 | inode->i_state &= ~I_SYNC; |
484 | if (!(inode->i_state & (I_FREEING | I_CLEAR))) { |
485 | if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) { |
486 | /* |
487 | * More pages get dirtied by a fast dirtier. |
488 | */ |
489 | goto select_queue; |
490 | } else if (inode->i_state & I_DIRTY) { |
491 | /* |
492 | * At least XFS will redirty the inode during the |
493 | * writeback (delalloc) and on io completion (isize). |
494 | */ |
495 | redirty_tail(inode); |
496 | } else if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { |
497 | /* |
498 | * We didn't write back all the pages. nfs_writepages() |
499 | * sometimes bales out without doing anything. Redirty |
500 | * the inode; Move it from b_io onto b_more_io/b_dirty. |
501 | */ |
502 | /* |
503 | * akpm: if the caller was the kupdate function we put |
504 | * this inode at the head of b_dirty so it gets first |
505 | * consideration. Otherwise, move it to the tail, for |
506 | * the reasons described there. I'm not really sure |
507 | * how much sense this makes. Presumably I had a good |
508 | * reasons for doing it this way, and I'd rather not |
509 | * muck with it at present. |
510 | */ |
511 | if (wbc->for_kupdate) { |
512 | /* |
513 | * For the kupdate function we move the inode |
514 | * to b_more_io so it will get more writeout as |
515 | * soon as the queue becomes uncongested. |
516 | */ |
517 | inode->i_state |= I_DIRTY_PAGES; |
518 | select_queue: |
519 | if (wbc->nr_to_write <= 0) { |
520 | /* |
521 | * slice used up: queue for next turn |
522 | */ |
523 | requeue_io(inode); |
524 | } else { |
525 | /* |
526 | * somehow blocked: retry later |
527 | */ |
528 | redirty_tail(inode); |
529 | } |
530 | } else { |
531 | /* |
532 | * Otherwise fully redirty the inode so that |
533 | * other inodes on this superblock will get some |
534 | * writeout. Otherwise heavy writing to one |
535 | * file would indefinitely suspend writeout of |
536 | * all the other files. |
537 | */ |
538 | inode->i_state |= I_DIRTY_PAGES; |
539 | redirty_tail(inode); |
540 | } |
541 | } else if (atomic_read(&inode->i_count)) { |
542 | /* |
543 | * The inode is clean, inuse |
544 | */ |
545 | list_move(&inode->i_list, &inode_in_use); |
546 | } else { |
547 | /* |
548 | * The inode is clean, unused |
549 | */ |
550 | list_move(&inode->i_list, &inode_unused); |
551 | } |
552 | } |
553 | inode_sync_complete(inode); |
554 | return ret; |
555 | } |
556 | |
557 | static void unpin_sb_for_writeback(struct super_block *sb) |
558 | { |
559 | up_read(&sb->s_umount); |
560 | put_super(sb); |
561 | } |
562 | |
563 | enum sb_pin_state { |
564 | SB_PINNED, |
565 | SB_NOT_PINNED, |
566 | SB_PIN_FAILED |
567 | }; |
568 | |
569 | /* |
570 | * For WB_SYNC_NONE writeback, the caller does not have the sb pinned |
571 | * before calling writeback. So make sure that we do pin it, so it doesn't |
572 | * go away while we are writing inodes from it. |
573 | */ |
574 | static enum sb_pin_state pin_sb_for_writeback(struct writeback_control *wbc, |
575 | struct super_block *sb) |
576 | { |
577 | /* |
578 | * Caller must already hold the ref for this |
579 | */ |
580 | if (wbc->sync_mode == WB_SYNC_ALL) { |
581 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
582 | return SB_NOT_PINNED; |
583 | } |
584 | spin_lock(&sb_lock); |
585 | sb->s_count++; |
586 | if (down_read_trylock(&sb->s_umount)) { |
587 | if (sb->s_root) { |
588 | spin_unlock(&sb_lock); |
589 | return SB_PINNED; |
590 | } |
591 | /* |
592 | * umounted, drop rwsem again and fall through to failure |
593 | */ |
594 | up_read(&sb->s_umount); |
595 | } |
596 | sb->s_count--; |
597 | spin_unlock(&sb_lock); |
598 | return SB_PIN_FAILED; |
599 | } |
600 | |
601 | /* |
602 | * Write a portion of b_io inodes which belong to @sb. |
603 | * If @wbc->sb != NULL, then find and write all such |
604 | * inodes. Otherwise write only ones which go sequentially |
605 | * in reverse order. |
606 | * Return 1, if the caller writeback routine should be |
607 | * interrupted. Otherwise return 0. |
608 | */ |
609 | static int writeback_sb_inodes(struct super_block *sb, |
610 | struct bdi_writeback *wb, |
611 | struct writeback_control *wbc) |
612 | { |
613 | while (!list_empty(&wb->b_io)) { |
614 | long pages_skipped; |
615 | struct inode *inode = list_entry(wb->b_io.prev, |
616 | struct inode, i_list); |
617 | if (wbc->sb && sb != inode->i_sb) { |
618 | /* super block given and doesn't |
619 | match, skip this inode */ |
620 | redirty_tail(inode); |
621 | continue; |
622 | } |
623 | if (sb != inode->i_sb) |
624 | /* finish with this superblock */ |
625 | return 0; |
626 | if (inode->i_state & (I_NEW | I_WILL_FREE)) { |
627 | requeue_io(inode); |
628 | continue; |
629 | } |
630 | /* |
631 | * Was this inode dirtied after sync_sb_inodes was called? |
632 | * This keeps sync from extra jobs and livelock. |
633 | */ |
634 | if (inode_dirtied_after(inode, wbc->wb_start)) |
635 | return 1; |
636 | |
637 | BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); |
638 | __iget(inode); |
639 | pages_skipped = wbc->pages_skipped; |
640 | writeback_single_inode(inode, wbc); |
641 | if (wbc->pages_skipped != pages_skipped) { |
642 | /* |
643 | * writeback is not making progress due to locked |
644 | * buffers. Skip this inode for now. |
645 | */ |
646 | redirty_tail(inode); |
647 | } |
648 | spin_unlock(&inode_lock); |
649 | iput(inode); |
650 | cond_resched(); |
651 | spin_lock(&inode_lock); |
652 | if (wbc->nr_to_write <= 0) { |
653 | wbc->more_io = 1; |
654 | return 1; |
655 | } |
656 | if (!list_empty(&wb->b_more_io)) |
657 | wbc->more_io = 1; |
658 | } |
659 | /* b_io is empty */ |
660 | return 1; |
661 | } |
662 | |
663 | static void writeback_inodes_wb(struct bdi_writeback *wb, |
664 | struct writeback_control *wbc) |
665 | { |
666 | int ret = 0; |
667 | |
668 | wbc->wb_start = jiffies; /* livelock avoidance */ |
669 | spin_lock(&inode_lock); |
670 | if (!wbc->for_kupdate || list_empty(&wb->b_io)) |
671 | queue_io(wb, wbc->older_than_this); |
672 | |
673 | while (!list_empty(&wb->b_io)) { |
674 | struct inode *inode = list_entry(wb->b_io.prev, |
675 | struct inode, i_list); |
676 | struct super_block *sb = inode->i_sb; |
677 | enum sb_pin_state state; |
678 | |
679 | if (wbc->sb && sb != wbc->sb) { |
680 | /* super block given and doesn't |
681 | match, skip this inode */ |
682 | redirty_tail(inode); |
683 | continue; |
684 | } |
685 | state = pin_sb_for_writeback(wbc, sb); |
686 | |
687 | if (state == SB_PIN_FAILED) { |
688 | requeue_io(inode); |
689 | continue; |
690 | } |
691 | ret = writeback_sb_inodes(sb, wb, wbc); |
692 | |
693 | if (state == SB_PINNED) |
694 | unpin_sb_for_writeback(sb); |
695 | if (ret) |
696 | break; |
697 | } |
698 | spin_unlock(&inode_lock); |
699 | /* Leave any unwritten inodes on b_io */ |
700 | } |
701 | |
702 | void writeback_inodes_wbc(struct writeback_control *wbc) |
703 | { |
704 | struct backing_dev_info *bdi = wbc->bdi; |
705 | |
706 | writeback_inodes_wb(&bdi->wb, wbc); |
707 | } |
708 | |
709 | /* |
710 | * The maximum number of pages to writeout in a single bdi flush/kupdate |
711 | * operation. We do this so we don't hold I_SYNC against an inode for |
712 | * enormous amounts of time, which would block a userspace task which has |
713 | * been forced to throttle against that inode. Also, the code reevaluates |
714 | * the dirty each time it has written this many pages. |
715 | */ |
716 | #define MAX_WRITEBACK_PAGES 1024 |
717 | |
718 | static inline bool over_bground_thresh(void) |
719 | { |
720 | unsigned long background_thresh, dirty_thresh; |
721 | |
722 | get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); |
723 | |
724 | return (global_page_state(NR_FILE_DIRTY) + |
725 | global_page_state(NR_UNSTABLE_NFS) >= background_thresh); |
726 | } |
727 | |
728 | /* |
729 | * Explicit flushing or periodic writeback of "old" data. |
730 | * |
731 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
732 | * dirtying-time in the inode's address_space. So this periodic writeback code |
733 | * just walks the superblock inode list, writing back any inodes which are |
734 | * older than a specific point in time. |
735 | * |
736 | * Try to run once per dirty_writeback_interval. But if a writeback event |
737 | * takes longer than a dirty_writeback_interval interval, then leave a |
738 | * one-second gap. |
739 | * |
740 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
741 | * all dirty pages if they are all attached to "old" mappings. |
742 | */ |
743 | static long wb_writeback(struct bdi_writeback *wb, |
744 | struct wb_writeback_args *args) |
745 | { |
746 | struct writeback_control wbc = { |
747 | .bdi = wb->bdi, |
748 | .sb = args->sb, |
749 | .sync_mode = args->sync_mode, |
750 | .older_than_this = NULL, |
751 | .for_kupdate = args->for_kupdate, |
752 | .for_background = args->for_background, |
753 | .range_cyclic = args->range_cyclic, |
754 | }; |
755 | unsigned long oldest_jif; |
756 | long wrote = 0; |
757 | struct inode *inode; |
758 | |
759 | if (wbc.for_kupdate) { |
760 | wbc.older_than_this = &oldest_jif; |
761 | oldest_jif = jiffies - |
762 | msecs_to_jiffies(dirty_expire_interval * 10); |
763 | } |
764 | if (!wbc.range_cyclic) { |
765 | wbc.range_start = 0; |
766 | wbc.range_end = LLONG_MAX; |
767 | } |
768 | |
769 | for (;;) { |
770 | /* |
771 | * Stop writeback when nr_pages has been consumed |
772 | */ |
773 | if (args->nr_pages <= 0) |
774 | break; |
775 | |
776 | /* |
777 | * For background writeout, stop when we are below the |
778 | * background dirty threshold |
779 | */ |
780 | if (args->for_background && !over_bground_thresh()) |
781 | break; |
782 | |
783 | wbc.more_io = 0; |
784 | wbc.nr_to_write = MAX_WRITEBACK_PAGES; |
785 | wbc.pages_skipped = 0; |
786 | writeback_inodes_wb(wb, &wbc); |
787 | args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
788 | wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
789 | |
790 | /* |
791 | * If we consumed everything, see if we have more |
792 | */ |
793 | if (wbc.nr_to_write <= 0) |
794 | continue; |
795 | /* |
796 | * Didn't write everything and we don't have more IO, bail |
797 | */ |
798 | if (!wbc.more_io) |
799 | break; |
800 | /* |
801 | * Did we write something? Try for more |
802 | */ |
803 | if (wbc.nr_to_write < MAX_WRITEBACK_PAGES) |
804 | continue; |
805 | /* |
806 | * Nothing written. Wait for some inode to |
807 | * become available for writeback. Otherwise |
808 | * we'll just busyloop. |
809 | */ |
810 | spin_lock(&inode_lock); |
811 | if (!list_empty(&wb->b_more_io)) { |
812 | inode = list_entry(wb->b_more_io.prev, |
813 | struct inode, i_list); |
814 | inode_wait_for_writeback(inode); |
815 | } |
816 | spin_unlock(&inode_lock); |
817 | } |
818 | |
819 | return wrote; |
820 | } |
821 | |
822 | /* |
823 | * Return the next bdi_work struct that hasn't been processed by this |
824 | * wb thread yet. ->seen is initially set for each thread that exists |
825 | * for this device, when a thread first notices a piece of work it |
826 | * clears its bit. Depending on writeback type, the thread will notify |
827 | * completion on either receiving the work (WB_SYNC_NONE) or after |
828 | * it is done (WB_SYNC_ALL). |
829 | */ |
830 | static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi, |
831 | struct bdi_writeback *wb) |
832 | { |
833 | struct bdi_work *work, *ret = NULL; |
834 | |
835 | rcu_read_lock(); |
836 | |
837 | list_for_each_entry_rcu(work, &bdi->work_list, list) { |
838 | if (!test_bit(wb->nr, &work->seen)) |
839 | continue; |
840 | clear_bit(wb->nr, &work->seen); |
841 | |
842 | ret = work; |
843 | break; |
844 | } |
845 | |
846 | rcu_read_unlock(); |
847 | return ret; |
848 | } |
849 | |
850 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
851 | { |
852 | unsigned long expired; |
853 | long nr_pages; |
854 | |
855 | expired = wb->last_old_flush + |
856 | msecs_to_jiffies(dirty_writeback_interval * 10); |
857 | if (time_before(jiffies, expired)) |
858 | return 0; |
859 | |
860 | wb->last_old_flush = jiffies; |
861 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
862 | global_page_state(NR_UNSTABLE_NFS) + |
863 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
864 | |
865 | if (nr_pages) { |
866 | struct wb_writeback_args args = { |
867 | .nr_pages = nr_pages, |
868 | .sync_mode = WB_SYNC_NONE, |
869 | .for_kupdate = 1, |
870 | .range_cyclic = 1, |
871 | }; |
872 | |
873 | return wb_writeback(wb, &args); |
874 | } |
875 | |
876 | return 0; |
877 | } |
878 | |
879 | /* |
880 | * Retrieve work items and do the writeback they describe |
881 | */ |
882 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) |
883 | { |
884 | struct backing_dev_info *bdi = wb->bdi; |
885 | struct bdi_work *work; |
886 | long wrote = 0; |
887 | |
888 | while ((work = get_next_work_item(bdi, wb)) != NULL) { |
889 | struct wb_writeback_args args = work->args; |
890 | |
891 | /* |
892 | * Override sync mode, in case we must wait for completion |
893 | */ |
894 | if (force_wait) |
895 | work->args.sync_mode = args.sync_mode = WB_SYNC_ALL; |
896 | |
897 | /* |
898 | * If this isn't a data integrity operation, just notify |
899 | * that we have seen this work and we are now starting it. |
900 | */ |
901 | if (args.sync_mode == WB_SYNC_NONE) |
902 | wb_clear_pending(wb, work); |
903 | |
904 | wrote += wb_writeback(wb, &args); |
905 | |
906 | /* |
907 | * This is a data integrity writeback, so only do the |
908 | * notification when we have completed the work. |
909 | */ |
910 | if (args.sync_mode == WB_SYNC_ALL) |
911 | wb_clear_pending(wb, work); |
912 | } |
913 | |
914 | /* |
915 | * Check for periodic writeback, kupdated() style |
916 | */ |
917 | wrote += wb_check_old_data_flush(wb); |
918 | |
919 | return wrote; |
920 | } |
921 | |
922 | /* |
923 | * Handle writeback of dirty data for the device backed by this bdi. Also |
924 | * wakes up periodically and does kupdated style flushing. |
925 | */ |
926 | int bdi_writeback_task(struct bdi_writeback *wb) |
927 | { |
928 | unsigned long last_active = jiffies; |
929 | unsigned long wait_jiffies = -1UL; |
930 | long pages_written; |
931 | |
932 | while (!kthread_should_stop()) { |
933 | pages_written = wb_do_writeback(wb, 0); |
934 | |
935 | if (pages_written) |
936 | last_active = jiffies; |
937 | else if (wait_jiffies != -1UL) { |
938 | unsigned long max_idle; |
939 | |
940 | /* |
941 | * Longest period of inactivity that we tolerate. If we |
942 | * see dirty data again later, the task will get |
943 | * recreated automatically. |
944 | */ |
945 | max_idle = max(5UL * 60 * HZ, wait_jiffies); |
946 | if (time_after(jiffies, max_idle + last_active)) |
947 | break; |
948 | } |
949 | |
950 | wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); |
951 | schedule_timeout_interruptible(wait_jiffies); |
952 | try_to_freeze(); |
953 | } |
954 | |
955 | return 0; |
956 | } |
957 | |
958 | /* |
959 | * Schedule writeback for all backing devices. This does WB_SYNC_NONE |
960 | * writeback, for integrity writeback see bdi_sync_writeback(). |
961 | */ |
962 | static void bdi_writeback_all(struct super_block *sb, long nr_pages) |
963 | { |
964 | struct wb_writeback_args args = { |
965 | .sb = sb, |
966 | .nr_pages = nr_pages, |
967 | .sync_mode = WB_SYNC_NONE, |
968 | }; |
969 | struct backing_dev_info *bdi; |
970 | |
971 | rcu_read_lock(); |
972 | |
973 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
974 | if (!bdi_has_dirty_io(bdi)) |
975 | continue; |
976 | |
977 | bdi_alloc_queue_work(bdi, &args); |
978 | } |
979 | |
980 | rcu_read_unlock(); |
981 | } |
982 | |
983 | /* |
984 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
985 | * the whole world. |
986 | */ |
987 | void wakeup_flusher_threads(long nr_pages) |
988 | { |
989 | if (nr_pages == 0) |
990 | nr_pages = global_page_state(NR_FILE_DIRTY) + |
991 | global_page_state(NR_UNSTABLE_NFS); |
992 | bdi_writeback_all(NULL, nr_pages); |
993 | } |
994 | |
995 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
996 | { |
997 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { |
998 | struct dentry *dentry; |
999 | const char *name = "?"; |
1000 | |
1001 | dentry = d_find_alias(inode); |
1002 | if (dentry) { |
1003 | spin_lock(&dentry->d_lock); |
1004 | name = (const char *) dentry->d_name.name; |
1005 | } |
1006 | printk(KERN_DEBUG |
1007 | "%s(%d): dirtied inode %lu (%s) on %s\n", |
1008 | current->comm, task_pid_nr(current), inode->i_ino, |
1009 | name, inode->i_sb->s_id); |
1010 | if (dentry) { |
1011 | spin_unlock(&dentry->d_lock); |
1012 | dput(dentry); |
1013 | } |
1014 | } |
1015 | } |
1016 | |
1017 | /** |
1018 | * __mark_inode_dirty - internal function |
1019 | * @inode: inode to mark |
1020 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) |
1021 | * Mark an inode as dirty. Callers should use mark_inode_dirty or |
1022 | * mark_inode_dirty_sync. |
1023 | * |
1024 | * Put the inode on the super block's dirty list. |
1025 | * |
1026 | * CAREFUL! We mark it dirty unconditionally, but move it onto the |
1027 | * dirty list only if it is hashed or if it refers to a blockdev. |
1028 | * If it was not hashed, it will never be added to the dirty list |
1029 | * even if it is later hashed, as it will have been marked dirty already. |
1030 | * |
1031 | * In short, make sure you hash any inodes _before_ you start marking |
1032 | * them dirty. |
1033 | * |
1034 | * This function *must* be atomic for the I_DIRTY_PAGES case - |
1035 | * set_page_dirty() is called under spinlock in several places. |
1036 | * |
1037 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
1038 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of |
1039 | * the kernel-internal blockdev inode represents the dirtying time of the |
1040 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use |
1041 | * page->mapping->host, so the page-dirtying time is recorded in the internal |
1042 | * blockdev inode. |
1043 | */ |
1044 | void __mark_inode_dirty(struct inode *inode, int flags) |
1045 | { |
1046 | struct super_block *sb = inode->i_sb; |
1047 | |
1048 | /* |
1049 | * Don't do this for I_DIRTY_PAGES - that doesn't actually |
1050 | * dirty the inode itself |
1051 | */ |
1052 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { |
1053 | if (sb->s_op->dirty_inode) |
1054 | sb->s_op->dirty_inode(inode); |
1055 | } |
1056 | |
1057 | /* |
1058 | * make sure that changes are seen by all cpus before we test i_state |
1059 | * -- mikulas |
1060 | */ |
1061 | smp_mb(); |
1062 | |
1063 | /* avoid the locking if we can */ |
1064 | if ((inode->i_state & flags) == flags) |
1065 | return; |
1066 | |
1067 | if (unlikely(block_dump)) |
1068 | block_dump___mark_inode_dirty(inode); |
1069 | |
1070 | spin_lock(&inode_lock); |
1071 | if ((inode->i_state & flags) != flags) { |
1072 | const int was_dirty = inode->i_state & I_DIRTY; |
1073 | |
1074 | inode->i_state |= flags; |
1075 | |
1076 | /* |
1077 | * If the inode is being synced, just update its dirty state. |
1078 | * The unlocker will place the inode on the appropriate |
1079 | * superblock list, based upon its state. |
1080 | */ |
1081 | if (inode->i_state & I_SYNC) |
1082 | goto out; |
1083 | |
1084 | /* |
1085 | * Only add valid (hashed) inodes to the superblock's |
1086 | * dirty list. Add blockdev inodes as well. |
1087 | */ |
1088 | if (!S_ISBLK(inode->i_mode)) { |
1089 | if (hlist_unhashed(&inode->i_hash)) |
1090 | goto out; |
1091 | } |
1092 | if (inode->i_state & (I_FREEING|I_CLEAR)) |
1093 | goto out; |
1094 | |
1095 | /* |
1096 | * If the inode was already on b_dirty/b_io/b_more_io, don't |
1097 | * reposition it (that would break b_dirty time-ordering). |
1098 | */ |
1099 | if (!was_dirty) { |
1100 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
1101 | struct backing_dev_info *bdi = wb->bdi; |
1102 | |
1103 | if (bdi_cap_writeback_dirty(bdi) && |
1104 | !test_bit(BDI_registered, &bdi->state)) { |
1105 | WARN_ON(1); |
1106 | printk(KERN_ERR "bdi-%s not registered\n", |
1107 | bdi->name); |
1108 | } |
1109 | |
1110 | inode->dirtied_when = jiffies; |
1111 | list_move(&inode->i_list, &wb->b_dirty); |
1112 | } |
1113 | } |
1114 | out: |
1115 | spin_unlock(&inode_lock); |
1116 | } |
1117 | EXPORT_SYMBOL(__mark_inode_dirty); |
1118 | |
1119 | /* |
1120 | * Write out a superblock's list of dirty inodes. A wait will be performed |
1121 | * upon no inodes, all inodes or the final one, depending upon sync_mode. |
1122 | * |
1123 | * If older_than_this is non-NULL, then only write out inodes which |
1124 | * had their first dirtying at a time earlier than *older_than_this. |
1125 | * |
1126 | * If `bdi' is non-zero then we're being asked to writeback a specific queue. |
1127 | * This function assumes that the blockdev superblock's inodes are backed by |
1128 | * a variety of queues, so all inodes are searched. For other superblocks, |
1129 | * assume that all inodes are backed by the same queue. |
1130 | * |
1131 | * The inodes to be written are parked on bdi->b_io. They are moved back onto |
1132 | * bdi->b_dirty as they are selected for writing. This way, none can be missed |
1133 | * on the writer throttling path, and we get decent balancing between many |
1134 | * throttled threads: we don't want them all piling up on inode_sync_wait. |
1135 | */ |
1136 | static void wait_sb_inodes(struct super_block *sb) |
1137 | { |
1138 | struct inode *inode, *old_inode = NULL; |
1139 | |
1140 | /* |
1141 | * We need to be protected against the filesystem going from |
1142 | * r/o to r/w or vice versa. |
1143 | */ |
1144 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
1145 | |
1146 | spin_lock(&inode_lock); |
1147 | |
1148 | /* |
1149 | * Data integrity sync. Must wait for all pages under writeback, |
1150 | * because there may have been pages dirtied before our sync |
1151 | * call, but which had writeout started before we write it out. |
1152 | * In which case, the inode may not be on the dirty list, but |
1153 | * we still have to wait for that writeout. |
1154 | */ |
1155 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
1156 | struct address_space *mapping; |
1157 | |
1158 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) |
1159 | continue; |
1160 | mapping = inode->i_mapping; |
1161 | if (mapping->nrpages == 0) |
1162 | continue; |
1163 | __iget(inode); |
1164 | spin_unlock(&inode_lock); |
1165 | /* |
1166 | * We hold a reference to 'inode' so it couldn't have |
1167 | * been removed from s_inodes list while we dropped the |
1168 | * inode_lock. We cannot iput the inode now as we can |
1169 | * be holding the last reference and we cannot iput it |
1170 | * under inode_lock. So we keep the reference and iput |
1171 | * it later. |
1172 | */ |
1173 | iput(old_inode); |
1174 | old_inode = inode; |
1175 | |
1176 | filemap_fdatawait(mapping); |
1177 | |
1178 | cond_resched(); |
1179 | |
1180 | spin_lock(&inode_lock); |
1181 | } |
1182 | spin_unlock(&inode_lock); |
1183 | iput(old_inode); |
1184 | } |
1185 | |
1186 | /** |
1187 | * writeback_inodes_sb - writeback dirty inodes from given super_block |
1188 | * @sb: the superblock |
1189 | * |
1190 | * Start writeback on some inodes on this super_block. No guarantees are made |
1191 | * on how many (if any) will be written, and this function does not wait |
1192 | * for IO completion of submitted IO. The number of pages submitted is |
1193 | * returned. |
1194 | */ |
1195 | void writeback_inodes_sb(struct super_block *sb) |
1196 | { |
1197 | unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); |
1198 | unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); |
1199 | long nr_to_write; |
1200 | |
1201 | nr_to_write = nr_dirty + nr_unstable + |
1202 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
1203 | |
1204 | bdi_start_writeback(sb->s_bdi, sb, nr_to_write); |
1205 | } |
1206 | EXPORT_SYMBOL(writeback_inodes_sb); |
1207 | |
1208 | /** |
1209 | * writeback_inodes_sb_if_idle - start writeback if none underway |
1210 | * @sb: the superblock |
1211 | * |
1212 | * Invoke writeback_inodes_sb if no writeback is currently underway. |
1213 | * Returns 1 if writeback was started, 0 if not. |
1214 | */ |
1215 | int writeback_inodes_sb_if_idle(struct super_block *sb) |
1216 | { |
1217 | if (!writeback_in_progress(sb->s_bdi)) { |
1218 | writeback_inodes_sb(sb); |
1219 | return 1; |
1220 | } else |
1221 | return 0; |
1222 | } |
1223 | EXPORT_SYMBOL(writeback_inodes_sb_if_idle); |
1224 | |
1225 | /** |
1226 | * sync_inodes_sb - sync sb inode pages |
1227 | * @sb: the superblock |
1228 | * |
1229 | * This function writes and waits on any dirty inode belonging to this |
1230 | * super_block. The number of pages synced is returned. |
1231 | */ |
1232 | void sync_inodes_sb(struct super_block *sb) |
1233 | { |
1234 | bdi_sync_writeback(sb->s_bdi, sb); |
1235 | wait_sb_inodes(sb); |
1236 | } |
1237 | EXPORT_SYMBOL(sync_inodes_sb); |
1238 | |
1239 | /** |
1240 | * write_inode_now - write an inode to disk |
1241 | * @inode: inode to write to disk |
1242 | * @sync: whether the write should be synchronous or not |
1243 | * |
1244 | * This function commits an inode to disk immediately if it is dirty. This is |
1245 | * primarily needed by knfsd. |
1246 | * |
1247 | * The caller must either have a ref on the inode or must have set I_WILL_FREE. |
1248 | */ |
1249 | int write_inode_now(struct inode *inode, int sync) |
1250 | { |
1251 | int ret; |
1252 | struct writeback_control wbc = { |
1253 | .nr_to_write = LONG_MAX, |
1254 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
1255 | .range_start = 0, |
1256 | .range_end = LLONG_MAX, |
1257 | }; |
1258 | |
1259 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) |
1260 | wbc.nr_to_write = 0; |
1261 | |
1262 | might_sleep(); |
1263 | spin_lock(&inode_lock); |
1264 | ret = writeback_single_inode(inode, &wbc); |
1265 | spin_unlock(&inode_lock); |
1266 | if (sync) |
1267 | inode_sync_wait(inode); |
1268 | return ret; |
1269 | } |
1270 | EXPORT_SYMBOL(write_inode_now); |
1271 | |
1272 | /** |
1273 | * sync_inode - write an inode and its pages to disk. |
1274 | * @inode: the inode to sync |
1275 | * @wbc: controls the writeback mode |
1276 | * |
1277 | * sync_inode() will write an inode and its pages to disk. It will also |
1278 | * correctly update the inode on its superblock's dirty inode lists and will |
1279 | * update inode->i_state. |
1280 | * |
1281 | * The caller must have a ref on the inode. |
1282 | */ |
1283 | int sync_inode(struct inode *inode, struct writeback_control *wbc) |
1284 | { |
1285 | int ret; |
1286 | |
1287 | spin_lock(&inode_lock); |
1288 | ret = writeback_single_inode(inode, wbc); |
1289 | spin_unlock(&inode_lock); |
1290 | return ret; |
1291 | } |
1292 | EXPORT_SYMBOL(sync_inode); |
1293 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9