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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> | |
f5ff8422 | 17 | #include <linux/module.h> |
1da177e4 LT |
18 | #include <linux/spinlock.h> |
19 | #include <linux/sched.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/mm.h> | |
03ba3782 JA |
22 | #include <linux/kthread.h> |
23 | #include <linux/freezer.h> | |
1da177e4 LT |
24 | #include <linux/writeback.h> |
25 | #include <linux/blkdev.h> | |
26 | #include <linux/backing-dev.h> | |
27 | #include <linux/buffer_head.h> | |
07f3f05c | 28 | #include "internal.h" |
1da177e4 | 29 | |
66f3b8e2 | 30 | #define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info) |
f11b00f3 | 31 | |
d0bceac7 JA |
32 | /* |
33 | * We don't actually have pdflush, but this one is exported though /proc... | |
34 | */ | |
35 | int nr_pdflush_threads; | |
36 | ||
c4a77a6c JA |
37 | /* |
38 | * Passed into wb_writeback(), essentially a subset of writeback_control | |
39 | */ | |
40 | struct wb_writeback_args { | |
41 | long nr_pages; | |
42 | struct super_block *sb; | |
43 | enum writeback_sync_modes sync_mode; | |
44 | int for_kupdate; | |
45 | int range_cyclic; | |
46 | }; | |
47 | ||
03ba3782 JA |
48 | /* |
49 | * Work items for the bdi_writeback threads | |
f11b00f3 | 50 | */ |
03ba3782 JA |
51 | struct bdi_work { |
52 | struct list_head list; | |
03ba3782 JA |
53 | struct rcu_head rcu_head; |
54 | ||
55 | unsigned long seen; | |
56 | atomic_t pending; | |
57 | ||
c4a77a6c | 58 | struct wb_writeback_args args; |
03ba3782 JA |
59 | |
60 | unsigned long state; | |
61 | }; | |
62 | ||
63 | enum { | |
64 | WS_USED_B = 0, | |
65 | WS_ONSTACK_B, | |
66 | }; | |
67 | ||
68 | #define WS_USED (1 << WS_USED_B) | |
69 | #define WS_ONSTACK (1 << WS_ONSTACK_B) | |
70 | ||
71 | static inline bool bdi_work_on_stack(struct bdi_work *work) | |
72 | { | |
73 | return test_bit(WS_ONSTACK_B, &work->state); | |
74 | } | |
75 | ||
76 | static inline void bdi_work_init(struct bdi_work *work, | |
77 | struct writeback_control *wbc) | |
78 | { | |
79 | INIT_RCU_HEAD(&work->rcu_head); | |
c4a77a6c JA |
80 | work->args.sb = wbc->sb; |
81 | work->args.nr_pages = wbc->nr_to_write; | |
82 | work->args.sync_mode = wbc->sync_mode; | |
83 | work->args.range_cyclic = wbc->range_cyclic; | |
84 | work->args.for_kupdate = 0; | |
03ba3782 JA |
85 | work->state = WS_USED; |
86 | } | |
87 | ||
f11b00f3 AB |
88 | /** |
89 | * writeback_in_progress - determine whether there is writeback in progress | |
90 | * @bdi: the device's backing_dev_info structure. | |
91 | * | |
03ba3782 JA |
92 | * Determine whether there is writeback waiting to be handled against a |
93 | * backing device. | |
f11b00f3 AB |
94 | */ |
95 | int writeback_in_progress(struct backing_dev_info *bdi) | |
96 | { | |
03ba3782 | 97 | return !list_empty(&bdi->work_list); |
f11b00f3 AB |
98 | } |
99 | ||
03ba3782 | 100 | static void bdi_work_clear(struct bdi_work *work) |
f11b00f3 | 101 | { |
03ba3782 JA |
102 | clear_bit(WS_USED_B, &work->state); |
103 | smp_mb__after_clear_bit(); | |
104 | wake_up_bit(&work->state, WS_USED_B); | |
f11b00f3 AB |
105 | } |
106 | ||
03ba3782 | 107 | static void bdi_work_free(struct rcu_head *head) |
4195f73d | 108 | { |
03ba3782 | 109 | struct bdi_work *work = container_of(head, struct bdi_work, rcu_head); |
4195f73d | 110 | |
03ba3782 JA |
111 | if (!bdi_work_on_stack(work)) |
112 | kfree(work); | |
113 | else | |
114 | bdi_work_clear(work); | |
4195f73d NP |
115 | } |
116 | ||
03ba3782 | 117 | static void wb_work_complete(struct bdi_work *work) |
1da177e4 | 118 | { |
c4a77a6c | 119 | const enum writeback_sync_modes sync_mode = work->args.sync_mode; |
1da177e4 LT |
120 | |
121 | /* | |
03ba3782 JA |
122 | * For allocated work, we can clear the done/seen bit right here. |
123 | * For on-stack work, we need to postpone both the clear and free | |
124 | * to after the RCU grace period, since the stack could be invalidated | |
125 | * as soon as bdi_work_clear() has done the wakeup. | |
1da177e4 | 126 | */ |
03ba3782 JA |
127 | if (!bdi_work_on_stack(work)) |
128 | bdi_work_clear(work); | |
129 | if (sync_mode == WB_SYNC_NONE || bdi_work_on_stack(work)) | |
130 | call_rcu(&work->rcu_head, bdi_work_free); | |
131 | } | |
1da177e4 | 132 | |
03ba3782 JA |
133 | static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) |
134 | { | |
1da177e4 | 135 | /* |
03ba3782 JA |
136 | * The caller has retrieved the work arguments from this work, |
137 | * drop our reference. If this is the last ref, delete and free it | |
1da177e4 | 138 | */ |
03ba3782 JA |
139 | if (atomic_dec_and_test(&work->pending)) { |
140 | struct backing_dev_info *bdi = wb->bdi; | |
1da177e4 | 141 | |
03ba3782 JA |
142 | spin_lock(&bdi->wb_lock); |
143 | list_del_rcu(&work->list); | |
144 | spin_unlock(&bdi->wb_lock); | |
1da177e4 | 145 | |
03ba3782 JA |
146 | wb_work_complete(work); |
147 | } | |
148 | } | |
1da177e4 | 149 | |
03ba3782 JA |
150 | static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work) |
151 | { | |
152 | if (work) { | |
153 | work->seen = bdi->wb_mask; | |
154 | BUG_ON(!work->seen); | |
155 | atomic_set(&work->pending, bdi->wb_cnt); | |
156 | BUG_ON(!bdi->wb_cnt); | |
1da177e4 LT |
157 | |
158 | /* | |
03ba3782 | 159 | * Make sure stores are seen before it appears on the list |
1da177e4 | 160 | */ |
03ba3782 | 161 | smp_mb(); |
1da177e4 | 162 | |
03ba3782 JA |
163 | spin_lock(&bdi->wb_lock); |
164 | list_add_tail_rcu(&work->list, &bdi->work_list); | |
165 | spin_unlock(&bdi->wb_lock); | |
166 | } | |
167 | ||
168 | /* | |
169 | * If the default thread isn't there, make sure we add it. When | |
170 | * it gets created and wakes up, we'll run this work. | |
171 | */ | |
172 | if (unlikely(list_empty_careful(&bdi->wb_list))) | |
173 | wake_up_process(default_backing_dev_info.wb.task); | |
174 | else { | |
175 | struct bdi_writeback *wb = &bdi->wb; | |
1da177e4 LT |
176 | |
177 | /* | |
03ba3782 JA |
178 | * If we failed allocating the bdi work item, wake up the wb |
179 | * thread always. As a safety precaution, it'll flush out | |
180 | * everything | |
1da177e4 | 181 | */ |
03ba3782 JA |
182 | if (!wb_has_dirty_io(wb)) { |
183 | if (work) | |
184 | wb_clear_pending(wb, work); | |
185 | } else if (wb->task) | |
186 | wake_up_process(wb->task); | |
1da177e4 | 187 | } |
1da177e4 LT |
188 | } |
189 | ||
03ba3782 JA |
190 | /* |
191 | * Used for on-stack allocated work items. The caller needs to wait until | |
192 | * the wb threads have acked the work before it's safe to continue. | |
193 | */ | |
194 | static void bdi_wait_on_work_clear(struct bdi_work *work) | |
195 | { | |
196 | wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait, | |
197 | TASK_UNINTERRUPTIBLE); | |
198 | } | |
1da177e4 | 199 | |
f11fcae8 JA |
200 | static void bdi_alloc_queue_work(struct backing_dev_info *bdi, |
201 | struct writeback_control *wbc) | |
1da177e4 | 202 | { |
03ba3782 JA |
203 | struct bdi_work *work; |
204 | ||
205 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
206 | if (work) | |
207 | bdi_work_init(work, wbc); | |
208 | ||
f11fcae8 | 209 | bdi_queue_work(bdi, work); |
03ba3782 JA |
210 | } |
211 | ||
212 | void bdi_start_writeback(struct writeback_control *wbc) | |
213 | { | |
f0fad8a5 CH |
214 | /* |
215 | * WB_SYNC_NONE is opportunistic writeback. If this allocation fails, | |
216 | * bdi_queue_work() will wake up the thread and flush old data. This | |
217 | * should ensure some amount of progress in freeing memory. | |
218 | */ | |
f11fcae8 JA |
219 | if (wbc->sync_mode != WB_SYNC_ALL) |
220 | bdi_alloc_queue_work(wbc->bdi, wbc); | |
221 | else { | |
f0fad8a5 | 222 | struct bdi_work work; |
03ba3782 | 223 | |
f0fad8a5 CH |
224 | bdi_work_init(&work, wbc); |
225 | work.state |= WS_ONSTACK; | |
03ba3782 | 226 | |
f0fad8a5 CH |
227 | bdi_queue_work(wbc->bdi, &work); |
228 | bdi_wait_on_work_clear(&work); | |
03ba3782 | 229 | } |
1da177e4 LT |
230 | } |
231 | ||
6610a0bc AM |
232 | /* |
233 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the | |
234 | * furthest end of its superblock's dirty-inode list. | |
235 | * | |
236 | * Before stamping the inode's ->dirtied_when, we check to see whether it is | |
66f3b8e2 | 237 | * already the most-recently-dirtied inode on the b_dirty list. If that is |
6610a0bc AM |
238 | * the case then the inode must have been redirtied while it was being written |
239 | * out and we don't reset its dirtied_when. | |
240 | */ | |
241 | static void redirty_tail(struct inode *inode) | |
242 | { | |
03ba3782 | 243 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
6610a0bc | 244 | |
03ba3782 | 245 | if (!list_empty(&wb->b_dirty)) { |
66f3b8e2 | 246 | struct inode *tail; |
6610a0bc | 247 | |
03ba3782 | 248 | tail = list_entry(wb->b_dirty.next, struct inode, i_list); |
66f3b8e2 | 249 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
6610a0bc AM |
250 | inode->dirtied_when = jiffies; |
251 | } | |
03ba3782 | 252 | list_move(&inode->i_list, &wb->b_dirty); |
6610a0bc AM |
253 | } |
254 | ||
c986d1e2 | 255 | /* |
66f3b8e2 | 256 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
c986d1e2 | 257 | */ |
0e0f4fc2 | 258 | static void requeue_io(struct inode *inode) |
c986d1e2 | 259 | { |
03ba3782 JA |
260 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
261 | ||
262 | list_move(&inode->i_list, &wb->b_more_io); | |
c986d1e2 AM |
263 | } |
264 | ||
1c0eeaf5 JE |
265 | static void inode_sync_complete(struct inode *inode) |
266 | { | |
267 | /* | |
268 | * Prevent speculative execution through spin_unlock(&inode_lock); | |
269 | */ | |
270 | smp_mb(); | |
271 | wake_up_bit(&inode->i_state, __I_SYNC); | |
272 | } | |
273 | ||
d2caa3c5 JL |
274 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
275 | { | |
276 | bool ret = time_after(inode->dirtied_when, t); | |
277 | #ifndef CONFIG_64BIT | |
278 | /* | |
279 | * For inodes being constantly redirtied, dirtied_when can get stuck. | |
280 | * It _appears_ to be in the future, but is actually in distant past. | |
281 | * This test is necessary to prevent such wrapped-around relative times | |
282 | * from permanently stopping the whole pdflush writeback. | |
283 | */ | |
284 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); | |
285 | #endif | |
286 | return ret; | |
287 | } | |
288 | ||
2c136579 FW |
289 | /* |
290 | * Move expired dirty inodes from @delaying_queue to @dispatch_queue. | |
291 | */ | |
292 | static void move_expired_inodes(struct list_head *delaying_queue, | |
293 | struct list_head *dispatch_queue, | |
294 | unsigned long *older_than_this) | |
295 | { | |
296 | while (!list_empty(delaying_queue)) { | |
297 | struct inode *inode = list_entry(delaying_queue->prev, | |
298 | struct inode, i_list); | |
299 | if (older_than_this && | |
d2caa3c5 | 300 | inode_dirtied_after(inode, *older_than_this)) |
2c136579 FW |
301 | break; |
302 | list_move(&inode->i_list, dispatch_queue); | |
303 | } | |
304 | } | |
305 | ||
306 | /* | |
307 | * Queue all expired dirty inodes for io, eldest first. | |
308 | */ | |
03ba3782 | 309 | static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this) |
66f3b8e2 | 310 | { |
03ba3782 JA |
311 | list_splice_init(&wb->b_more_io, wb->b_io.prev); |
312 | move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); | |
66f3b8e2 JA |
313 | } |
314 | ||
03ba3782 | 315 | static int write_inode(struct inode *inode, int sync) |
08d8e974 | 316 | { |
03ba3782 JA |
317 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) |
318 | return inode->i_sb->s_op->write_inode(inode, sync); | |
319 | return 0; | |
08d8e974 | 320 | } |
08d8e974 | 321 | |
1da177e4 | 322 | /* |
01c03194 CH |
323 | * Wait for writeback on an inode to complete. |
324 | */ | |
325 | static void inode_wait_for_writeback(struct inode *inode) | |
326 | { | |
327 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); | |
328 | wait_queue_head_t *wqh; | |
329 | ||
330 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
331 | do { | |
332 | spin_unlock(&inode_lock); | |
333 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); | |
334 | spin_lock(&inode_lock); | |
335 | } while (inode->i_state & I_SYNC); | |
336 | } | |
337 | ||
338 | /* | |
339 | * Write out an inode's dirty pages. Called under inode_lock. Either the | |
340 | * caller has ref on the inode (either via __iget or via syscall against an fd) | |
341 | * or the inode has I_WILL_FREE set (via generic_forget_inode) | |
342 | * | |
1da177e4 LT |
343 | * If `wait' is set, wait on the writeout. |
344 | * | |
345 | * The whole writeout design is quite complex and fragile. We want to avoid | |
346 | * starvation of particular inodes when others are being redirtied, prevent | |
347 | * livelocks, etc. | |
348 | * | |
349 | * Called under inode_lock. | |
350 | */ | |
351 | static int | |
01c03194 | 352 | writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
1da177e4 | 353 | { |
1da177e4 | 354 | struct address_space *mapping = inode->i_mapping; |
1da177e4 | 355 | int wait = wbc->sync_mode == WB_SYNC_ALL; |
01c03194 | 356 | unsigned dirty; |
1da177e4 LT |
357 | int ret; |
358 | ||
01c03194 CH |
359 | if (!atomic_read(&inode->i_count)) |
360 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); | |
361 | else | |
362 | WARN_ON(inode->i_state & I_WILL_FREE); | |
363 | ||
364 | if (inode->i_state & I_SYNC) { | |
365 | /* | |
366 | * If this inode is locked for writeback and we are not doing | |
66f3b8e2 | 367 | * writeback-for-data-integrity, move it to b_more_io so that |
01c03194 CH |
368 | * writeback can proceed with the other inodes on s_io. |
369 | * | |
370 | * We'll have another go at writing back this inode when we | |
66f3b8e2 | 371 | * completed a full scan of b_io. |
01c03194 CH |
372 | */ |
373 | if (!wait) { | |
374 | requeue_io(inode); | |
375 | return 0; | |
376 | } | |
377 | ||
378 | /* | |
379 | * It's a data-integrity sync. We must wait. | |
380 | */ | |
381 | inode_wait_for_writeback(inode); | |
382 | } | |
383 | ||
1c0eeaf5 | 384 | BUG_ON(inode->i_state & I_SYNC); |
1da177e4 | 385 | |
1c0eeaf5 | 386 | /* Set I_SYNC, reset I_DIRTY */ |
1da177e4 | 387 | dirty = inode->i_state & I_DIRTY; |
1c0eeaf5 | 388 | inode->i_state |= I_SYNC; |
1da177e4 LT |
389 | inode->i_state &= ~I_DIRTY; |
390 | ||
391 | spin_unlock(&inode_lock); | |
392 | ||
393 | ret = do_writepages(mapping, wbc); | |
394 | ||
395 | /* Don't write the inode if only I_DIRTY_PAGES was set */ | |
396 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
397 | int err = write_inode(inode, wait); | |
398 | if (ret == 0) | |
399 | ret = err; | |
400 | } | |
401 | ||
402 | if (wait) { | |
403 | int err = filemap_fdatawait(mapping); | |
404 | if (ret == 0) | |
405 | ret = err; | |
406 | } | |
407 | ||
408 | spin_lock(&inode_lock); | |
1c0eeaf5 | 409 | inode->i_state &= ~I_SYNC; |
84a89245 | 410 | if (!(inode->i_state & (I_FREEING | I_CLEAR))) { |
1da177e4 LT |
411 | if (!(inode->i_state & I_DIRTY) && |
412 | mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { | |
413 | /* | |
414 | * We didn't write back all the pages. nfs_writepages() | |
415 | * sometimes bales out without doing anything. Redirty | |
66f3b8e2 | 416 | * the inode; Move it from b_io onto b_more_io/b_dirty. |
1b43ef91 AM |
417 | */ |
418 | /* | |
419 | * akpm: if the caller was the kupdate function we put | |
66f3b8e2 | 420 | * this inode at the head of b_dirty so it gets first |
1b43ef91 AM |
421 | * consideration. Otherwise, move it to the tail, for |
422 | * the reasons described there. I'm not really sure | |
423 | * how much sense this makes. Presumably I had a good | |
424 | * reasons for doing it this way, and I'd rather not | |
425 | * muck with it at present. | |
1da177e4 LT |
426 | */ |
427 | if (wbc->for_kupdate) { | |
428 | /* | |
2c136579 | 429 | * For the kupdate function we move the inode |
66f3b8e2 | 430 | * to b_more_io so it will get more writeout as |
2c136579 | 431 | * soon as the queue becomes uncongested. |
1da177e4 LT |
432 | */ |
433 | inode->i_state |= I_DIRTY_PAGES; | |
8bc3be27 FW |
434 | if (wbc->nr_to_write <= 0) { |
435 | /* | |
436 | * slice used up: queue for next turn | |
437 | */ | |
438 | requeue_io(inode); | |
439 | } else { | |
440 | /* | |
441 | * somehow blocked: retry later | |
442 | */ | |
443 | redirty_tail(inode); | |
444 | } | |
1da177e4 LT |
445 | } else { |
446 | /* | |
447 | * Otherwise fully redirty the inode so that | |
448 | * other inodes on this superblock will get some | |
449 | * writeout. Otherwise heavy writing to one | |
450 | * file would indefinitely suspend writeout of | |
451 | * all the other files. | |
452 | */ | |
453 | inode->i_state |= I_DIRTY_PAGES; | |
1b43ef91 | 454 | redirty_tail(inode); |
1da177e4 LT |
455 | } |
456 | } else if (inode->i_state & I_DIRTY) { | |
457 | /* | |
458 | * Someone redirtied the inode while were writing back | |
459 | * the pages. | |
460 | */ | |
6610a0bc | 461 | redirty_tail(inode); |
1da177e4 LT |
462 | } else if (atomic_read(&inode->i_count)) { |
463 | /* | |
464 | * The inode is clean, inuse | |
465 | */ | |
466 | list_move(&inode->i_list, &inode_in_use); | |
467 | } else { | |
468 | /* | |
469 | * The inode is clean, unused | |
470 | */ | |
471 | list_move(&inode->i_list, &inode_unused); | |
1da177e4 LT |
472 | } |
473 | } | |
1c0eeaf5 | 474 | inode_sync_complete(inode); |
1da177e4 LT |
475 | return ret; |
476 | } | |
477 | ||
03ba3782 JA |
478 | /* |
479 | * For WB_SYNC_NONE writeback, the caller does not have the sb pinned | |
480 | * before calling writeback. So make sure that we do pin it, so it doesn't | |
481 | * go away while we are writing inodes from it. | |
482 | * | |
483 | * Returns 0 if the super was successfully pinned (or pinning wasn't needed), | |
484 | * 1 if we failed. | |
485 | */ | |
486 | static int pin_sb_for_writeback(struct writeback_control *wbc, | |
487 | struct inode *inode) | |
488 | { | |
489 | struct super_block *sb = inode->i_sb; | |
490 | ||
491 | /* | |
492 | * Caller must already hold the ref for this | |
493 | */ | |
494 | if (wbc->sync_mode == WB_SYNC_ALL) { | |
495 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); | |
496 | return 0; | |
497 | } | |
498 | ||
499 | spin_lock(&sb_lock); | |
500 | sb->s_count++; | |
501 | if (down_read_trylock(&sb->s_umount)) { | |
502 | if (sb->s_root) { | |
503 | spin_unlock(&sb_lock); | |
504 | return 0; | |
505 | } | |
506 | /* | |
507 | * umounted, drop rwsem again and fall through to failure | |
508 | */ | |
509 | up_read(&sb->s_umount); | |
510 | } | |
511 | ||
512 | sb->s_count--; | |
513 | spin_unlock(&sb_lock); | |
514 | return 1; | |
515 | } | |
516 | ||
517 | static void unpin_sb_for_writeback(struct writeback_control *wbc, | |
518 | struct inode *inode) | |
519 | { | |
520 | struct super_block *sb = inode->i_sb; | |
521 | ||
522 | if (wbc->sync_mode == WB_SYNC_ALL) | |
523 | return; | |
524 | ||
525 | up_read(&sb->s_umount); | |
526 | put_super(sb); | |
527 | } | |
528 | ||
529 | static void writeback_inodes_wb(struct bdi_writeback *wb, | |
530 | struct writeback_control *wbc) | |
1da177e4 | 531 | { |
03ba3782 | 532 | struct super_block *sb = wbc->sb; |
66f3b8e2 | 533 | const int is_blkdev_sb = sb_is_blkdev_sb(sb); |
1da177e4 LT |
534 | const unsigned long start = jiffies; /* livelock avoidance */ |
535 | ||
ae8547b0 | 536 | spin_lock(&inode_lock); |
1da177e4 | 537 | |
03ba3782 JA |
538 | if (!wbc->for_kupdate || list_empty(&wb->b_io)) |
539 | queue_io(wb, wbc->older_than_this); | |
66f3b8e2 | 540 | |
03ba3782 JA |
541 | while (!list_empty(&wb->b_io)) { |
542 | struct inode *inode = list_entry(wb->b_io.prev, | |
1da177e4 | 543 | struct inode, i_list); |
1da177e4 LT |
544 | long pages_skipped; |
545 | ||
66f3b8e2 JA |
546 | /* |
547 | * super block given and doesn't match, skip this inode | |
548 | */ | |
549 | if (sb && sb != inode->i_sb) { | |
550 | redirty_tail(inode); | |
551 | continue; | |
552 | } | |
553 | ||
03ba3782 | 554 | if (!bdi_cap_writeback_dirty(wb->bdi)) { |
9852a0e7 | 555 | redirty_tail(inode); |
66f3b8e2 | 556 | if (is_blkdev_sb) { |
1da177e4 LT |
557 | /* |
558 | * Dirty memory-backed blockdev: the ramdisk | |
559 | * driver does this. Skip just this inode | |
560 | */ | |
561 | continue; | |
562 | } | |
563 | /* | |
564 | * Dirty memory-backed inode against a filesystem other | |
565 | * than the kernel-internal bdev filesystem. Skip the | |
566 | * entire superblock. | |
567 | */ | |
568 | break; | |
569 | } | |
570 | ||
84a89245 | 571 | if (inode->i_state & (I_NEW | I_WILL_FREE)) { |
7ef0d737 NP |
572 | requeue_io(inode); |
573 | continue; | |
574 | } | |
575 | ||
03ba3782 | 576 | if (wbc->nonblocking && bdi_write_congested(wb->bdi)) { |
1da177e4 | 577 | wbc->encountered_congestion = 1; |
66f3b8e2 | 578 | if (!is_blkdev_sb) |
1da177e4 | 579 | break; /* Skip a congested fs */ |
0e0f4fc2 | 580 | requeue_io(inode); |
1da177e4 LT |
581 | continue; /* Skip a congested blockdev */ |
582 | } | |
583 | ||
d2caa3c5 JL |
584 | /* |
585 | * Was this inode dirtied after sync_sb_inodes was called? | |
586 | * This keeps sync from extra jobs and livelock. | |
587 | */ | |
588 | if (inode_dirtied_after(inode, start)) | |
1da177e4 LT |
589 | break; |
590 | ||
03ba3782 JA |
591 | if (pin_sb_for_writeback(wbc, inode)) { |
592 | requeue_io(inode); | |
593 | continue; | |
594 | } | |
1da177e4 | 595 | |
84a89245 | 596 | BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); |
1da177e4 LT |
597 | __iget(inode); |
598 | pages_skipped = wbc->pages_skipped; | |
01c03194 | 599 | writeback_single_inode(inode, wbc); |
03ba3782 | 600 | unpin_sb_for_writeback(wbc, inode); |
1da177e4 LT |
601 | if (wbc->pages_skipped != pages_skipped) { |
602 | /* | |
603 | * writeback is not making progress due to locked | |
604 | * buffers. Skip this inode for now. | |
605 | */ | |
f57b9b7b | 606 | redirty_tail(inode); |
1da177e4 LT |
607 | } |
608 | spin_unlock(&inode_lock); | |
1da177e4 | 609 | iput(inode); |
4ffc8444 | 610 | cond_resched(); |
1da177e4 | 611 | spin_lock(&inode_lock); |
8bc3be27 FW |
612 | if (wbc->nr_to_write <= 0) { |
613 | wbc->more_io = 1; | |
1da177e4 | 614 | break; |
8bc3be27 | 615 | } |
03ba3782 | 616 | if (!list_empty(&wb->b_more_io)) |
8bc3be27 | 617 | wbc->more_io = 1; |
1da177e4 | 618 | } |
38f21977 | 619 | |
66f3b8e2 JA |
620 | spin_unlock(&inode_lock); |
621 | /* Leave any unwritten inodes on b_io */ | |
622 | } | |
623 | ||
03ba3782 JA |
624 | void writeback_inodes_wbc(struct writeback_control *wbc) |
625 | { | |
626 | struct backing_dev_info *bdi = wbc->bdi; | |
627 | ||
628 | writeback_inodes_wb(&bdi->wb, wbc); | |
629 | } | |
630 | ||
66f3b8e2 | 631 | /* |
03ba3782 JA |
632 | * The maximum number of pages to writeout in a single bdi flush/kupdate |
633 | * operation. We do this so we don't hold I_SYNC against an inode for | |
634 | * enormous amounts of time, which would block a userspace task which has | |
635 | * been forced to throttle against that inode. Also, the code reevaluates | |
636 | * the dirty each time it has written this many pages. | |
637 | */ | |
638 | #define MAX_WRITEBACK_PAGES 1024 | |
639 | ||
640 | static inline bool over_bground_thresh(void) | |
641 | { | |
642 | unsigned long background_thresh, dirty_thresh; | |
643 | ||
644 | get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); | |
645 | ||
646 | return (global_page_state(NR_FILE_DIRTY) + | |
647 | global_page_state(NR_UNSTABLE_NFS) >= background_thresh); | |
648 | } | |
649 | ||
650 | /* | |
651 | * Explicit flushing or periodic writeback of "old" data. | |
66f3b8e2 | 652 | * |
03ba3782 JA |
653 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
654 | * dirtying-time in the inode's address_space. So this periodic writeback code | |
655 | * just walks the superblock inode list, writing back any inodes which are | |
656 | * older than a specific point in time. | |
66f3b8e2 | 657 | * |
03ba3782 JA |
658 | * Try to run once per dirty_writeback_interval. But if a writeback event |
659 | * takes longer than a dirty_writeback_interval interval, then leave a | |
660 | * one-second gap. | |
66f3b8e2 | 661 | * |
03ba3782 JA |
662 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
663 | * all dirty pages if they are all attached to "old" mappings. | |
66f3b8e2 | 664 | */ |
c4a77a6c JA |
665 | static long wb_writeback(struct bdi_writeback *wb, |
666 | struct wb_writeback_args *args) | |
66f3b8e2 | 667 | { |
03ba3782 JA |
668 | struct writeback_control wbc = { |
669 | .bdi = wb->bdi, | |
c4a77a6c JA |
670 | .sb = args->sb, |
671 | .sync_mode = args->sync_mode, | |
03ba3782 | 672 | .older_than_this = NULL, |
c4a77a6c JA |
673 | .for_kupdate = args->for_kupdate, |
674 | .range_cyclic = args->range_cyclic, | |
03ba3782 JA |
675 | }; |
676 | unsigned long oldest_jif; | |
677 | long wrote = 0; | |
66f3b8e2 | 678 | |
03ba3782 JA |
679 | if (wbc.for_kupdate) { |
680 | wbc.older_than_this = &oldest_jif; | |
681 | oldest_jif = jiffies - | |
682 | msecs_to_jiffies(dirty_expire_interval * 10); | |
683 | } | |
c4a77a6c JA |
684 | if (!wbc.range_cyclic) { |
685 | wbc.range_start = 0; | |
686 | wbc.range_end = LLONG_MAX; | |
687 | } | |
38f21977 | 688 | |
03ba3782 JA |
689 | for (;;) { |
690 | /* | |
691 | * Don't flush anything for non-integrity writeback where | |
692 | * no nr_pages was given | |
693 | */ | |
c4a77a6c JA |
694 | if (!args->for_kupdate && args->nr_pages <= 0 && |
695 | args->sync_mode == WB_SYNC_NONE) | |
03ba3782 | 696 | break; |
66f3b8e2 | 697 | |
38f21977 | 698 | /* |
03ba3782 JA |
699 | * If no specific pages were given and this is just a |
700 | * periodic background writeout and we are below the | |
701 | * background dirty threshold, don't do anything | |
38f21977 | 702 | */ |
c4a77a6c JA |
703 | if (args->for_kupdate && args->nr_pages <= 0 && |
704 | !over_bground_thresh()) | |
03ba3782 | 705 | break; |
38f21977 | 706 | |
03ba3782 JA |
707 | wbc.more_io = 0; |
708 | wbc.encountered_congestion = 0; | |
709 | wbc.nr_to_write = MAX_WRITEBACK_PAGES; | |
710 | wbc.pages_skipped = 0; | |
711 | writeback_inodes_wb(wb, &wbc); | |
c4a77a6c | 712 | args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
03ba3782 JA |
713 | wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; |
714 | ||
715 | /* | |
716 | * If we ran out of stuff to write, bail unless more_io got set | |
717 | */ | |
718 | if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) { | |
719 | if (wbc.more_io && !wbc.for_kupdate) | |
38f21977 | 720 | continue; |
03ba3782 JA |
721 | break; |
722 | } | |
723 | } | |
724 | ||
725 | return wrote; | |
726 | } | |
727 | ||
728 | /* | |
729 | * Return the next bdi_work struct that hasn't been processed by this | |
730 | * wb thread yet | |
731 | */ | |
732 | static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi, | |
733 | struct bdi_writeback *wb) | |
734 | { | |
735 | struct bdi_work *work, *ret = NULL; | |
736 | ||
737 | rcu_read_lock(); | |
738 | ||
739 | list_for_each_entry_rcu(work, &bdi->work_list, list) { | |
740 | if (!test_and_clear_bit(wb->nr, &work->seen)) | |
741 | continue; | |
742 | ||
743 | ret = work; | |
744 | break; | |
745 | } | |
746 | ||
747 | rcu_read_unlock(); | |
748 | return ret; | |
749 | } | |
750 | ||
751 | static long wb_check_old_data_flush(struct bdi_writeback *wb) | |
752 | { | |
753 | unsigned long expired; | |
754 | long nr_pages; | |
755 | ||
756 | expired = wb->last_old_flush + | |
757 | msecs_to_jiffies(dirty_writeback_interval * 10); | |
758 | if (time_before(jiffies, expired)) | |
759 | return 0; | |
760 | ||
761 | wb->last_old_flush = jiffies; | |
762 | nr_pages = global_page_state(NR_FILE_DIRTY) + | |
763 | global_page_state(NR_UNSTABLE_NFS) + | |
764 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); | |
765 | ||
c4a77a6c JA |
766 | if (nr_pages) { |
767 | struct wb_writeback_args args = { | |
768 | .nr_pages = nr_pages, | |
769 | .sync_mode = WB_SYNC_NONE, | |
770 | .for_kupdate = 1, | |
771 | .range_cyclic = 1, | |
772 | }; | |
773 | ||
774 | return wb_writeback(wb, &args); | |
775 | } | |
03ba3782 JA |
776 | |
777 | return 0; | |
778 | } | |
779 | ||
780 | /* | |
781 | * Retrieve work items and do the writeback they describe | |
782 | */ | |
783 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) | |
784 | { | |
785 | struct backing_dev_info *bdi = wb->bdi; | |
786 | struct bdi_work *work; | |
c4a77a6c | 787 | long wrote = 0; |
03ba3782 JA |
788 | |
789 | while ((work = get_next_work_item(bdi, wb)) != NULL) { | |
c4a77a6c | 790 | struct wb_writeback_args args = work->args; |
03ba3782 JA |
791 | |
792 | /* | |
793 | * Override sync mode, in case we must wait for completion | |
794 | */ | |
795 | if (force_wait) | |
c4a77a6c | 796 | work->args.sync_mode = args.sync_mode = WB_SYNC_ALL; |
03ba3782 JA |
797 | |
798 | /* | |
799 | * If this isn't a data integrity operation, just notify | |
800 | * that we have seen this work and we are now starting it. | |
801 | */ | |
c4a77a6c | 802 | if (args.sync_mode == WB_SYNC_NONE) |
03ba3782 JA |
803 | wb_clear_pending(wb, work); |
804 | ||
c4a77a6c | 805 | wrote += wb_writeback(wb, &args); |
03ba3782 JA |
806 | |
807 | /* | |
808 | * This is a data integrity writeback, so only do the | |
809 | * notification when we have completed the work. | |
810 | */ | |
c4a77a6c | 811 | if (args.sync_mode == WB_SYNC_ALL) |
03ba3782 JA |
812 | wb_clear_pending(wb, work); |
813 | } | |
814 | ||
815 | /* | |
816 | * Check for periodic writeback, kupdated() style | |
817 | */ | |
818 | wrote += wb_check_old_data_flush(wb); | |
819 | ||
820 | return wrote; | |
821 | } | |
822 | ||
823 | /* | |
824 | * Handle writeback of dirty data for the device backed by this bdi. Also | |
825 | * wakes up periodically and does kupdated style flushing. | |
826 | */ | |
827 | int bdi_writeback_task(struct bdi_writeback *wb) | |
828 | { | |
829 | unsigned long last_active = jiffies; | |
830 | unsigned long wait_jiffies = -1UL; | |
831 | long pages_written; | |
832 | ||
833 | while (!kthread_should_stop()) { | |
834 | pages_written = wb_do_writeback(wb, 0); | |
835 | ||
836 | if (pages_written) | |
837 | last_active = jiffies; | |
838 | else if (wait_jiffies != -1UL) { | |
839 | unsigned long max_idle; | |
840 | ||
38f21977 | 841 | /* |
03ba3782 JA |
842 | * Longest period of inactivity that we tolerate. If we |
843 | * see dirty data again later, the task will get | |
844 | * recreated automatically. | |
38f21977 | 845 | */ |
03ba3782 JA |
846 | max_idle = max(5UL * 60 * HZ, wait_jiffies); |
847 | if (time_after(jiffies, max_idle + last_active)) | |
848 | break; | |
849 | } | |
850 | ||
851 | wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); | |
852 | set_current_state(TASK_INTERRUPTIBLE); | |
853 | schedule_timeout(wait_jiffies); | |
854 | try_to_freeze(); | |
855 | } | |
856 | ||
857 | return 0; | |
858 | } | |
859 | ||
860 | /* | |
f11fcae8 JA |
861 | * Schedule writeback for all backing devices. Can only be used for |
862 | * WB_SYNC_NONE writeback, WB_SYNC_ALL should use bdi_start_writeback() | |
863 | * and pass in the superblock. | |
03ba3782 JA |
864 | */ |
865 | static void bdi_writeback_all(struct writeback_control *wbc) | |
866 | { | |
03ba3782 | 867 | struct backing_dev_info *bdi; |
03ba3782 | 868 | |
f11fcae8 JA |
869 | WARN_ON(wbc->sync_mode == WB_SYNC_ALL); |
870 | ||
cfc4ba53 | 871 | rcu_read_lock(); |
03ba3782 | 872 | |
cfc4ba53 | 873 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
03ba3782 JA |
874 | if (!bdi_has_dirty_io(bdi)) |
875 | continue; | |
38f21977 | 876 | |
f11fcae8 | 877 | bdi_alloc_queue_work(bdi, wbc); |
03ba3782 JA |
878 | } |
879 | ||
cfc4ba53 | 880 | rcu_read_unlock(); |
1da177e4 LT |
881 | } |
882 | ||
883 | /* | |
03ba3782 JA |
884 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
885 | * the whole world. | |
886 | */ | |
887 | void wakeup_flusher_threads(long nr_pages) | |
888 | { | |
889 | struct writeback_control wbc = { | |
890 | .sync_mode = WB_SYNC_NONE, | |
891 | .older_than_this = NULL, | |
892 | .range_cyclic = 1, | |
893 | }; | |
894 | ||
895 | if (nr_pages == 0) | |
896 | nr_pages = global_page_state(NR_FILE_DIRTY) + | |
897 | global_page_state(NR_UNSTABLE_NFS); | |
898 | wbc.nr_to_write = nr_pages; | |
899 | bdi_writeback_all(&wbc); | |
900 | } | |
901 | ||
902 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) | |
903 | { | |
904 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { | |
905 | struct dentry *dentry; | |
906 | const char *name = "?"; | |
907 | ||
908 | dentry = d_find_alias(inode); | |
909 | if (dentry) { | |
910 | spin_lock(&dentry->d_lock); | |
911 | name = (const char *) dentry->d_name.name; | |
912 | } | |
913 | printk(KERN_DEBUG | |
914 | "%s(%d): dirtied inode %lu (%s) on %s\n", | |
915 | current->comm, task_pid_nr(current), inode->i_ino, | |
916 | name, inode->i_sb->s_id); | |
917 | if (dentry) { | |
918 | spin_unlock(&dentry->d_lock); | |
919 | dput(dentry); | |
920 | } | |
921 | } | |
922 | } | |
923 | ||
924 | /** | |
925 | * __mark_inode_dirty - internal function | |
926 | * @inode: inode to mark | |
927 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) | |
928 | * Mark an inode as dirty. Callers should use mark_inode_dirty or | |
929 | * mark_inode_dirty_sync. | |
1da177e4 | 930 | * |
03ba3782 JA |
931 | * Put the inode on the super block's dirty list. |
932 | * | |
933 | * CAREFUL! We mark it dirty unconditionally, but move it onto the | |
934 | * dirty list only if it is hashed or if it refers to a blockdev. | |
935 | * If it was not hashed, it will never be added to the dirty list | |
936 | * even if it is later hashed, as it will have been marked dirty already. | |
937 | * | |
938 | * In short, make sure you hash any inodes _before_ you start marking | |
939 | * them dirty. | |
1da177e4 | 940 | * |
03ba3782 JA |
941 | * This function *must* be atomic for the I_DIRTY_PAGES case - |
942 | * set_page_dirty() is called under spinlock in several places. | |
1da177e4 | 943 | * |
03ba3782 JA |
944 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
945 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of | |
946 | * the kernel-internal blockdev inode represents the dirtying time of the | |
947 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use | |
948 | * page->mapping->host, so the page-dirtying time is recorded in the internal | |
949 | * blockdev inode. | |
1da177e4 | 950 | */ |
03ba3782 | 951 | void __mark_inode_dirty(struct inode *inode, int flags) |
1da177e4 | 952 | { |
03ba3782 | 953 | struct super_block *sb = inode->i_sb; |
1da177e4 | 954 | |
03ba3782 JA |
955 | /* |
956 | * Don't do this for I_DIRTY_PAGES - that doesn't actually | |
957 | * dirty the inode itself | |
958 | */ | |
959 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
960 | if (sb->s_op->dirty_inode) | |
961 | sb->s_op->dirty_inode(inode); | |
962 | } | |
963 | ||
964 | /* | |
965 | * make sure that changes are seen by all cpus before we test i_state | |
966 | * -- mikulas | |
967 | */ | |
968 | smp_mb(); | |
969 | ||
970 | /* avoid the locking if we can */ | |
971 | if ((inode->i_state & flags) == flags) | |
972 | return; | |
973 | ||
974 | if (unlikely(block_dump)) | |
975 | block_dump___mark_inode_dirty(inode); | |
976 | ||
977 | spin_lock(&inode_lock); | |
978 | if ((inode->i_state & flags) != flags) { | |
979 | const int was_dirty = inode->i_state & I_DIRTY; | |
980 | ||
981 | inode->i_state |= flags; | |
982 | ||
983 | /* | |
984 | * If the inode is being synced, just update its dirty state. | |
985 | * The unlocker will place the inode on the appropriate | |
986 | * superblock list, based upon its state. | |
987 | */ | |
988 | if (inode->i_state & I_SYNC) | |
989 | goto out; | |
990 | ||
991 | /* | |
992 | * Only add valid (hashed) inodes to the superblock's | |
993 | * dirty list. Add blockdev inodes as well. | |
994 | */ | |
995 | if (!S_ISBLK(inode->i_mode)) { | |
996 | if (hlist_unhashed(&inode->i_hash)) | |
997 | goto out; | |
998 | } | |
999 | if (inode->i_state & (I_FREEING|I_CLEAR)) | |
1000 | goto out; | |
1001 | ||
1002 | /* | |
1003 | * If the inode was already on b_dirty/b_io/b_more_io, don't | |
1004 | * reposition it (that would break b_dirty time-ordering). | |
1005 | */ | |
1006 | if (!was_dirty) { | |
1007 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; | |
500b067c JA |
1008 | struct backing_dev_info *bdi = wb->bdi; |
1009 | ||
1010 | if (bdi_cap_writeback_dirty(bdi) && | |
1011 | !test_bit(BDI_registered, &bdi->state)) { | |
1012 | WARN_ON(1); | |
1013 | printk(KERN_ERR "bdi-%s not registered\n", | |
1014 | bdi->name); | |
1015 | } | |
03ba3782 JA |
1016 | |
1017 | inode->dirtied_when = jiffies; | |
1018 | list_move(&inode->i_list, &wb->b_dirty); | |
1da177e4 | 1019 | } |
1da177e4 | 1020 | } |
03ba3782 JA |
1021 | out: |
1022 | spin_unlock(&inode_lock); | |
1023 | } | |
1024 | EXPORT_SYMBOL(__mark_inode_dirty); | |
1025 | ||
1026 | /* | |
1027 | * Write out a superblock's list of dirty inodes. A wait will be performed | |
1028 | * upon no inodes, all inodes or the final one, depending upon sync_mode. | |
1029 | * | |
1030 | * If older_than_this is non-NULL, then only write out inodes which | |
1031 | * had their first dirtying at a time earlier than *older_than_this. | |
1032 | * | |
1033 | * If we're a pdlfush thread, then implement pdflush collision avoidance | |
1034 | * against the entire list. | |
1035 | * | |
1036 | * If `bdi' is non-zero then we're being asked to writeback a specific queue. | |
1037 | * This function assumes that the blockdev superblock's inodes are backed by | |
1038 | * a variety of queues, so all inodes are searched. For other superblocks, | |
1039 | * assume that all inodes are backed by the same queue. | |
1040 | * | |
1041 | * The inodes to be written are parked on bdi->b_io. They are moved back onto | |
1042 | * bdi->b_dirty as they are selected for writing. This way, none can be missed | |
1043 | * on the writer throttling path, and we get decent balancing between many | |
1044 | * throttled threads: we don't want them all piling up on inode_sync_wait. | |
1045 | */ | |
1046 | static void wait_sb_inodes(struct writeback_control *wbc) | |
1047 | { | |
1048 | struct inode *inode, *old_inode = NULL; | |
1049 | ||
1050 | /* | |
1051 | * We need to be protected against the filesystem going from | |
1052 | * r/o to r/w or vice versa. | |
1053 | */ | |
1054 | WARN_ON(!rwsem_is_locked(&wbc->sb->s_umount)); | |
1055 | ||
1056 | spin_lock(&inode_lock); | |
1057 | ||
1058 | /* | |
1059 | * Data integrity sync. Must wait for all pages under writeback, | |
1060 | * because there may have been pages dirtied before our sync | |
1061 | * call, but which had writeout started before we write it out. | |
1062 | * In which case, the inode may not be on the dirty list, but | |
1063 | * we still have to wait for that writeout. | |
1064 | */ | |
1065 | list_for_each_entry(inode, &wbc->sb->s_inodes, i_sb_list) { | |
1066 | struct address_space *mapping; | |
1067 | ||
1068 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) | |
1069 | continue; | |
1070 | mapping = inode->i_mapping; | |
1071 | if (mapping->nrpages == 0) | |
1072 | continue; | |
1073 | __iget(inode); | |
1074 | spin_unlock(&inode_lock); | |
1075 | /* | |
1076 | * We hold a reference to 'inode' so it couldn't have | |
1077 | * been removed from s_inodes list while we dropped the | |
1078 | * inode_lock. We cannot iput the inode now as we can | |
1079 | * be holding the last reference and we cannot iput it | |
1080 | * under inode_lock. So we keep the reference and iput | |
1081 | * it later. | |
1082 | */ | |
1083 | iput(old_inode); | |
1084 | old_inode = inode; | |
1085 | ||
1086 | filemap_fdatawait(mapping); | |
1087 | ||
1088 | cond_resched(); | |
1089 | ||
1090 | spin_lock(&inode_lock); | |
1091 | } | |
1092 | spin_unlock(&inode_lock); | |
1093 | iput(old_inode); | |
1da177e4 LT |
1094 | } |
1095 | ||
d8a8559c JA |
1096 | /** |
1097 | * writeback_inodes_sb - writeback dirty inodes from given super_block | |
1098 | * @sb: the superblock | |
1da177e4 | 1099 | * |
d8a8559c JA |
1100 | * Start writeback on some inodes on this super_block. No guarantees are made |
1101 | * on how many (if any) will be written, and this function does not wait | |
1102 | * for IO completion of submitted IO. The number of pages submitted is | |
1103 | * returned. | |
1da177e4 | 1104 | */ |
d8a8559c | 1105 | long writeback_inodes_sb(struct super_block *sb) |
1da177e4 LT |
1106 | { |
1107 | struct writeback_control wbc = { | |
03ba3782 | 1108 | .sb = sb, |
d8a8559c | 1109 | .sync_mode = WB_SYNC_NONE, |
111ebb6e OH |
1110 | .range_start = 0, |
1111 | .range_end = LLONG_MAX, | |
1da177e4 | 1112 | }; |
d8a8559c JA |
1113 | unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); |
1114 | unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); | |
1115 | long nr_to_write; | |
1da177e4 | 1116 | |
d8a8559c | 1117 | nr_to_write = nr_dirty + nr_unstable + |
38f21977 | 1118 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
38f21977 | 1119 | |
d8a8559c | 1120 | wbc.nr_to_write = nr_to_write; |
03ba3782 | 1121 | bdi_writeback_all(&wbc); |
d8a8559c JA |
1122 | return nr_to_write - wbc.nr_to_write; |
1123 | } | |
1124 | EXPORT_SYMBOL(writeback_inodes_sb); | |
1125 | ||
1126 | /** | |
1127 | * sync_inodes_sb - sync sb inode pages | |
1128 | * @sb: the superblock | |
1129 | * | |
1130 | * This function writes and waits on any dirty inode belonging to this | |
1131 | * super_block. The number of pages synced is returned. | |
1132 | */ | |
1133 | long sync_inodes_sb(struct super_block *sb) | |
1134 | { | |
1135 | struct writeback_control wbc = { | |
03ba3782 | 1136 | .sb = sb, |
f11fcae8 | 1137 | .bdi = sb->s_bdi, |
d8a8559c JA |
1138 | .sync_mode = WB_SYNC_ALL, |
1139 | .range_start = 0, | |
1140 | .range_end = LLONG_MAX, | |
1141 | }; | |
1142 | long nr_to_write = LONG_MAX; /* doesn't actually matter */ | |
1143 | ||
1144 | wbc.nr_to_write = nr_to_write; | |
f11fcae8 | 1145 | bdi_start_writeback(&wbc); |
03ba3782 | 1146 | wait_sb_inodes(&wbc); |
d8a8559c | 1147 | return nr_to_write - wbc.nr_to_write; |
1da177e4 | 1148 | } |
d8a8559c | 1149 | EXPORT_SYMBOL(sync_inodes_sb); |
1da177e4 | 1150 | |
1da177e4 | 1151 | /** |
7f04c26d AA |
1152 | * write_inode_now - write an inode to disk |
1153 | * @inode: inode to write to disk | |
1154 | * @sync: whether the write should be synchronous or not | |
1155 | * | |
1156 | * This function commits an inode to disk immediately if it is dirty. This is | |
1157 | * primarily needed by knfsd. | |
1da177e4 | 1158 | * |
7f04c26d | 1159 | * The caller must either have a ref on the inode or must have set I_WILL_FREE. |
1da177e4 | 1160 | */ |
1da177e4 LT |
1161 | int write_inode_now(struct inode *inode, int sync) |
1162 | { | |
1163 | int ret; | |
1164 | struct writeback_control wbc = { | |
1165 | .nr_to_write = LONG_MAX, | |
18914b18 | 1166 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
111ebb6e OH |
1167 | .range_start = 0, |
1168 | .range_end = LLONG_MAX, | |
1da177e4 LT |
1169 | }; |
1170 | ||
1171 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) | |
49364ce2 | 1172 | wbc.nr_to_write = 0; |
1da177e4 LT |
1173 | |
1174 | might_sleep(); | |
1175 | spin_lock(&inode_lock); | |
01c03194 | 1176 | ret = writeback_single_inode(inode, &wbc); |
1da177e4 LT |
1177 | spin_unlock(&inode_lock); |
1178 | if (sync) | |
1c0eeaf5 | 1179 | inode_sync_wait(inode); |
1da177e4 LT |
1180 | return ret; |
1181 | } | |
1182 | EXPORT_SYMBOL(write_inode_now); | |
1183 | ||
1184 | /** | |
1185 | * sync_inode - write an inode and its pages to disk. | |
1186 | * @inode: the inode to sync | |
1187 | * @wbc: controls the writeback mode | |
1188 | * | |
1189 | * sync_inode() will write an inode and its pages to disk. It will also | |
1190 | * correctly update the inode on its superblock's dirty inode lists and will | |
1191 | * update inode->i_state. | |
1192 | * | |
1193 | * The caller must have a ref on the inode. | |
1194 | */ | |
1195 | int sync_inode(struct inode *inode, struct writeback_control *wbc) | |
1196 | { | |
1197 | int ret; | |
1198 | ||
1199 | spin_lock(&inode_lock); | |
01c03194 | 1200 | ret = writeback_single_inode(inode, wbc); |
1da177e4 LT |
1201 | spin_unlock(&inode_lock); |
1202 | return ret; | |
1203 | } | |
1204 | EXPORT_SYMBOL(sync_inode); |