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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 | ||
03ba3782 JA |
37 | /* |
38 | * Work items for the bdi_writeback threads | |
f11b00f3 | 39 | */ |
03ba3782 JA |
40 | struct bdi_work { |
41 | struct list_head list; | |
42 | struct list_head wait_list; | |
43 | struct rcu_head rcu_head; | |
44 | ||
45 | unsigned long seen; | |
46 | atomic_t pending; | |
47 | ||
48 | struct super_block *sb; | |
49 | unsigned long nr_pages; | |
50 | enum writeback_sync_modes sync_mode; | |
51 | ||
52 | unsigned long state; | |
53 | }; | |
54 | ||
55 | enum { | |
56 | WS_USED_B = 0, | |
57 | WS_ONSTACK_B, | |
58 | }; | |
59 | ||
60 | #define WS_USED (1 << WS_USED_B) | |
61 | #define WS_ONSTACK (1 << WS_ONSTACK_B) | |
62 | ||
63 | static inline bool bdi_work_on_stack(struct bdi_work *work) | |
64 | { | |
65 | return test_bit(WS_ONSTACK_B, &work->state); | |
66 | } | |
67 | ||
68 | static inline void bdi_work_init(struct bdi_work *work, | |
69 | struct writeback_control *wbc) | |
70 | { | |
71 | INIT_RCU_HEAD(&work->rcu_head); | |
72 | work->sb = wbc->sb; | |
73 | work->nr_pages = wbc->nr_to_write; | |
74 | work->sync_mode = wbc->sync_mode; | |
75 | work->state = WS_USED; | |
76 | } | |
77 | ||
f11b00f3 AB |
78 | /** |
79 | * writeback_in_progress - determine whether there is writeback in progress | |
80 | * @bdi: the device's backing_dev_info structure. | |
81 | * | |
03ba3782 JA |
82 | * Determine whether there is writeback waiting to be handled against a |
83 | * backing device. | |
f11b00f3 AB |
84 | */ |
85 | int writeback_in_progress(struct backing_dev_info *bdi) | |
86 | { | |
03ba3782 | 87 | return !list_empty(&bdi->work_list); |
f11b00f3 AB |
88 | } |
89 | ||
03ba3782 | 90 | static void bdi_work_clear(struct bdi_work *work) |
f11b00f3 | 91 | { |
03ba3782 JA |
92 | clear_bit(WS_USED_B, &work->state); |
93 | smp_mb__after_clear_bit(); | |
94 | wake_up_bit(&work->state, WS_USED_B); | |
f11b00f3 AB |
95 | } |
96 | ||
03ba3782 | 97 | static void bdi_work_free(struct rcu_head *head) |
4195f73d | 98 | { |
03ba3782 | 99 | struct bdi_work *work = container_of(head, struct bdi_work, rcu_head); |
4195f73d | 100 | |
03ba3782 JA |
101 | if (!bdi_work_on_stack(work)) |
102 | kfree(work); | |
103 | else | |
104 | bdi_work_clear(work); | |
4195f73d NP |
105 | } |
106 | ||
03ba3782 | 107 | static void wb_work_complete(struct bdi_work *work) |
1da177e4 | 108 | { |
03ba3782 | 109 | const enum writeback_sync_modes sync_mode = work->sync_mode; |
1da177e4 LT |
110 | |
111 | /* | |
03ba3782 JA |
112 | * For allocated work, we can clear the done/seen bit right here. |
113 | * For on-stack work, we need to postpone both the clear and free | |
114 | * to after the RCU grace period, since the stack could be invalidated | |
115 | * as soon as bdi_work_clear() has done the wakeup. | |
1da177e4 | 116 | */ |
03ba3782 JA |
117 | if (!bdi_work_on_stack(work)) |
118 | bdi_work_clear(work); | |
119 | if (sync_mode == WB_SYNC_NONE || bdi_work_on_stack(work)) | |
120 | call_rcu(&work->rcu_head, bdi_work_free); | |
121 | } | |
1da177e4 | 122 | |
03ba3782 JA |
123 | static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) |
124 | { | |
1da177e4 | 125 | /* |
03ba3782 JA |
126 | * The caller has retrieved the work arguments from this work, |
127 | * drop our reference. If this is the last ref, delete and free it | |
1da177e4 | 128 | */ |
03ba3782 JA |
129 | if (atomic_dec_and_test(&work->pending)) { |
130 | struct backing_dev_info *bdi = wb->bdi; | |
1da177e4 | 131 | |
03ba3782 JA |
132 | spin_lock(&bdi->wb_lock); |
133 | list_del_rcu(&work->list); | |
134 | spin_unlock(&bdi->wb_lock); | |
1da177e4 | 135 | |
03ba3782 JA |
136 | wb_work_complete(work); |
137 | } | |
138 | } | |
1da177e4 | 139 | |
03ba3782 JA |
140 | static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work) |
141 | { | |
142 | if (work) { | |
143 | work->seen = bdi->wb_mask; | |
144 | BUG_ON(!work->seen); | |
145 | atomic_set(&work->pending, bdi->wb_cnt); | |
146 | BUG_ON(!bdi->wb_cnt); | |
1da177e4 LT |
147 | |
148 | /* | |
03ba3782 | 149 | * Make sure stores are seen before it appears on the list |
1da177e4 | 150 | */ |
03ba3782 | 151 | smp_mb(); |
1da177e4 | 152 | |
03ba3782 JA |
153 | spin_lock(&bdi->wb_lock); |
154 | list_add_tail_rcu(&work->list, &bdi->work_list); | |
155 | spin_unlock(&bdi->wb_lock); | |
156 | } | |
157 | ||
158 | /* | |
159 | * If the default thread isn't there, make sure we add it. When | |
160 | * it gets created and wakes up, we'll run this work. | |
161 | */ | |
162 | if (unlikely(list_empty_careful(&bdi->wb_list))) | |
163 | wake_up_process(default_backing_dev_info.wb.task); | |
164 | else { | |
165 | struct bdi_writeback *wb = &bdi->wb; | |
1da177e4 LT |
166 | |
167 | /* | |
03ba3782 JA |
168 | * If we failed allocating the bdi work item, wake up the wb |
169 | * thread always. As a safety precaution, it'll flush out | |
170 | * everything | |
1da177e4 | 171 | */ |
03ba3782 JA |
172 | if (!wb_has_dirty_io(wb)) { |
173 | if (work) | |
174 | wb_clear_pending(wb, work); | |
175 | } else if (wb->task) | |
176 | wake_up_process(wb->task); | |
1da177e4 | 177 | } |
1da177e4 LT |
178 | } |
179 | ||
03ba3782 JA |
180 | /* |
181 | * Used for on-stack allocated work items. The caller needs to wait until | |
182 | * the wb threads have acked the work before it's safe to continue. | |
183 | */ | |
184 | static void bdi_wait_on_work_clear(struct bdi_work *work) | |
185 | { | |
186 | wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait, | |
187 | TASK_UNINTERRUPTIBLE); | |
188 | } | |
1da177e4 | 189 | |
03ba3782 | 190 | static struct bdi_work *bdi_alloc_work(struct writeback_control *wbc) |
1da177e4 | 191 | { |
03ba3782 JA |
192 | struct bdi_work *work; |
193 | ||
194 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
195 | if (work) | |
196 | bdi_work_init(work, wbc); | |
197 | ||
198 | return work; | |
199 | } | |
200 | ||
201 | void bdi_start_writeback(struct writeback_control *wbc) | |
202 | { | |
f0fad8a5 CH |
203 | /* |
204 | * WB_SYNC_NONE is opportunistic writeback. If this allocation fails, | |
205 | * bdi_queue_work() will wake up the thread and flush old data. This | |
206 | * should ensure some amount of progress in freeing memory. | |
207 | */ | |
208 | if (wbc->sync_mode != WB_SYNC_ALL) { | |
209 | struct bdi_work *w = bdi_alloc_work(wbc); | |
03ba3782 | 210 | |
f0fad8a5 CH |
211 | bdi_queue_work(wbc->bdi, w); |
212 | } else { | |
213 | struct bdi_work work; | |
03ba3782 | 214 | |
f0fad8a5 CH |
215 | bdi_work_init(&work, wbc); |
216 | work.state |= WS_ONSTACK; | |
03ba3782 | 217 | |
f0fad8a5 CH |
218 | bdi_queue_work(wbc->bdi, &work); |
219 | bdi_wait_on_work_clear(&work); | |
03ba3782 | 220 | } |
1da177e4 LT |
221 | } |
222 | ||
6610a0bc AM |
223 | /* |
224 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the | |
225 | * furthest end of its superblock's dirty-inode list. | |
226 | * | |
227 | * Before stamping the inode's ->dirtied_when, we check to see whether it is | |
66f3b8e2 | 228 | * already the most-recently-dirtied inode on the b_dirty list. If that is |
6610a0bc AM |
229 | * the case then the inode must have been redirtied while it was being written |
230 | * out and we don't reset its dirtied_when. | |
231 | */ | |
232 | static void redirty_tail(struct inode *inode) | |
233 | { | |
03ba3782 | 234 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
6610a0bc | 235 | |
03ba3782 | 236 | if (!list_empty(&wb->b_dirty)) { |
66f3b8e2 | 237 | struct inode *tail; |
6610a0bc | 238 | |
03ba3782 | 239 | tail = list_entry(wb->b_dirty.next, struct inode, i_list); |
66f3b8e2 | 240 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
6610a0bc AM |
241 | inode->dirtied_when = jiffies; |
242 | } | |
03ba3782 | 243 | list_move(&inode->i_list, &wb->b_dirty); |
6610a0bc AM |
244 | } |
245 | ||
c986d1e2 | 246 | /* |
66f3b8e2 | 247 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
c986d1e2 | 248 | */ |
0e0f4fc2 | 249 | static void requeue_io(struct inode *inode) |
c986d1e2 | 250 | { |
03ba3782 JA |
251 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
252 | ||
253 | list_move(&inode->i_list, &wb->b_more_io); | |
c986d1e2 AM |
254 | } |
255 | ||
1c0eeaf5 JE |
256 | static void inode_sync_complete(struct inode *inode) |
257 | { | |
258 | /* | |
259 | * Prevent speculative execution through spin_unlock(&inode_lock); | |
260 | */ | |
261 | smp_mb(); | |
262 | wake_up_bit(&inode->i_state, __I_SYNC); | |
263 | } | |
264 | ||
d2caa3c5 JL |
265 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
266 | { | |
267 | bool ret = time_after(inode->dirtied_when, t); | |
268 | #ifndef CONFIG_64BIT | |
269 | /* | |
270 | * For inodes being constantly redirtied, dirtied_when can get stuck. | |
271 | * It _appears_ to be in the future, but is actually in distant past. | |
272 | * This test is necessary to prevent such wrapped-around relative times | |
273 | * from permanently stopping the whole pdflush writeback. | |
274 | */ | |
275 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); | |
276 | #endif | |
277 | return ret; | |
278 | } | |
279 | ||
2c136579 FW |
280 | /* |
281 | * Move expired dirty inodes from @delaying_queue to @dispatch_queue. | |
282 | */ | |
283 | static void move_expired_inodes(struct list_head *delaying_queue, | |
284 | struct list_head *dispatch_queue, | |
285 | unsigned long *older_than_this) | |
286 | { | |
287 | while (!list_empty(delaying_queue)) { | |
288 | struct inode *inode = list_entry(delaying_queue->prev, | |
289 | struct inode, i_list); | |
290 | if (older_than_this && | |
d2caa3c5 | 291 | inode_dirtied_after(inode, *older_than_this)) |
2c136579 FW |
292 | break; |
293 | list_move(&inode->i_list, dispatch_queue); | |
294 | } | |
295 | } | |
296 | ||
297 | /* | |
298 | * Queue all expired dirty inodes for io, eldest first. | |
299 | */ | |
03ba3782 | 300 | static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this) |
66f3b8e2 | 301 | { |
03ba3782 JA |
302 | list_splice_init(&wb->b_more_io, wb->b_io.prev); |
303 | move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); | |
66f3b8e2 JA |
304 | } |
305 | ||
03ba3782 | 306 | static int write_inode(struct inode *inode, int sync) |
08d8e974 | 307 | { |
03ba3782 JA |
308 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) |
309 | return inode->i_sb->s_op->write_inode(inode, sync); | |
310 | return 0; | |
08d8e974 | 311 | } |
08d8e974 | 312 | |
1da177e4 | 313 | /* |
01c03194 CH |
314 | * Wait for writeback on an inode to complete. |
315 | */ | |
316 | static void inode_wait_for_writeback(struct inode *inode) | |
317 | { | |
318 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); | |
319 | wait_queue_head_t *wqh; | |
320 | ||
321 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
322 | do { | |
323 | spin_unlock(&inode_lock); | |
324 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); | |
325 | spin_lock(&inode_lock); | |
326 | } while (inode->i_state & I_SYNC); | |
327 | } | |
328 | ||
329 | /* | |
330 | * Write out an inode's dirty pages. Called under inode_lock. Either the | |
331 | * caller has ref on the inode (either via __iget or via syscall against an fd) | |
332 | * or the inode has I_WILL_FREE set (via generic_forget_inode) | |
333 | * | |
1da177e4 LT |
334 | * If `wait' is set, wait on the writeout. |
335 | * | |
336 | * The whole writeout design is quite complex and fragile. We want to avoid | |
337 | * starvation of particular inodes when others are being redirtied, prevent | |
338 | * livelocks, etc. | |
339 | * | |
340 | * Called under inode_lock. | |
341 | */ | |
342 | static int | |
01c03194 | 343 | writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
1da177e4 | 344 | { |
1da177e4 | 345 | struct address_space *mapping = inode->i_mapping; |
1da177e4 | 346 | int wait = wbc->sync_mode == WB_SYNC_ALL; |
01c03194 | 347 | unsigned dirty; |
1da177e4 LT |
348 | int ret; |
349 | ||
01c03194 CH |
350 | if (!atomic_read(&inode->i_count)) |
351 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); | |
352 | else | |
353 | WARN_ON(inode->i_state & I_WILL_FREE); | |
354 | ||
355 | if (inode->i_state & I_SYNC) { | |
356 | /* | |
357 | * If this inode is locked for writeback and we are not doing | |
66f3b8e2 | 358 | * writeback-for-data-integrity, move it to b_more_io so that |
01c03194 CH |
359 | * writeback can proceed with the other inodes on s_io. |
360 | * | |
361 | * We'll have another go at writing back this inode when we | |
66f3b8e2 | 362 | * completed a full scan of b_io. |
01c03194 CH |
363 | */ |
364 | if (!wait) { | |
365 | requeue_io(inode); | |
366 | return 0; | |
367 | } | |
368 | ||
369 | /* | |
370 | * It's a data-integrity sync. We must wait. | |
371 | */ | |
372 | inode_wait_for_writeback(inode); | |
373 | } | |
374 | ||
1c0eeaf5 | 375 | BUG_ON(inode->i_state & I_SYNC); |
1da177e4 | 376 | |
1c0eeaf5 | 377 | /* Set I_SYNC, reset I_DIRTY */ |
1da177e4 | 378 | dirty = inode->i_state & I_DIRTY; |
1c0eeaf5 | 379 | inode->i_state |= I_SYNC; |
1da177e4 LT |
380 | inode->i_state &= ~I_DIRTY; |
381 | ||
382 | spin_unlock(&inode_lock); | |
383 | ||
384 | ret = do_writepages(mapping, wbc); | |
385 | ||
386 | /* Don't write the inode if only I_DIRTY_PAGES was set */ | |
387 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
388 | int err = write_inode(inode, wait); | |
389 | if (ret == 0) | |
390 | ret = err; | |
391 | } | |
392 | ||
393 | if (wait) { | |
394 | int err = filemap_fdatawait(mapping); | |
395 | if (ret == 0) | |
396 | ret = err; | |
397 | } | |
398 | ||
399 | spin_lock(&inode_lock); | |
1c0eeaf5 | 400 | inode->i_state &= ~I_SYNC; |
84a89245 | 401 | if (!(inode->i_state & (I_FREEING | I_CLEAR))) { |
1da177e4 LT |
402 | if (!(inode->i_state & I_DIRTY) && |
403 | mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { | |
404 | /* | |
405 | * We didn't write back all the pages. nfs_writepages() | |
406 | * sometimes bales out without doing anything. Redirty | |
66f3b8e2 | 407 | * the inode; Move it from b_io onto b_more_io/b_dirty. |
1b43ef91 AM |
408 | */ |
409 | /* | |
410 | * akpm: if the caller was the kupdate function we put | |
66f3b8e2 | 411 | * this inode at the head of b_dirty so it gets first |
1b43ef91 AM |
412 | * consideration. Otherwise, move it to the tail, for |
413 | * the reasons described there. I'm not really sure | |
414 | * how much sense this makes. Presumably I had a good | |
415 | * reasons for doing it this way, and I'd rather not | |
416 | * muck with it at present. | |
1da177e4 LT |
417 | */ |
418 | if (wbc->for_kupdate) { | |
419 | /* | |
2c136579 | 420 | * For the kupdate function we move the inode |
66f3b8e2 | 421 | * to b_more_io so it will get more writeout as |
2c136579 | 422 | * soon as the queue becomes uncongested. |
1da177e4 LT |
423 | */ |
424 | inode->i_state |= I_DIRTY_PAGES; | |
8bc3be27 FW |
425 | if (wbc->nr_to_write <= 0) { |
426 | /* | |
427 | * slice used up: queue for next turn | |
428 | */ | |
429 | requeue_io(inode); | |
430 | } else { | |
431 | /* | |
432 | * somehow blocked: retry later | |
433 | */ | |
434 | redirty_tail(inode); | |
435 | } | |
1da177e4 LT |
436 | } else { |
437 | /* | |
438 | * Otherwise fully redirty the inode so that | |
439 | * other inodes on this superblock will get some | |
440 | * writeout. Otherwise heavy writing to one | |
441 | * file would indefinitely suspend writeout of | |
442 | * all the other files. | |
443 | */ | |
444 | inode->i_state |= I_DIRTY_PAGES; | |
1b43ef91 | 445 | redirty_tail(inode); |
1da177e4 LT |
446 | } |
447 | } else if (inode->i_state & I_DIRTY) { | |
448 | /* | |
449 | * Someone redirtied the inode while were writing back | |
450 | * the pages. | |
451 | */ | |
6610a0bc | 452 | redirty_tail(inode); |
1da177e4 LT |
453 | } else if (atomic_read(&inode->i_count)) { |
454 | /* | |
455 | * The inode is clean, inuse | |
456 | */ | |
457 | list_move(&inode->i_list, &inode_in_use); | |
458 | } else { | |
459 | /* | |
460 | * The inode is clean, unused | |
461 | */ | |
462 | list_move(&inode->i_list, &inode_unused); | |
1da177e4 LT |
463 | } |
464 | } | |
1c0eeaf5 | 465 | inode_sync_complete(inode); |
1da177e4 LT |
466 | return ret; |
467 | } | |
468 | ||
03ba3782 JA |
469 | /* |
470 | * For WB_SYNC_NONE writeback, the caller does not have the sb pinned | |
471 | * before calling writeback. So make sure that we do pin it, so it doesn't | |
472 | * go away while we are writing inodes from it. | |
473 | * | |
474 | * Returns 0 if the super was successfully pinned (or pinning wasn't needed), | |
475 | * 1 if we failed. | |
476 | */ | |
477 | static int pin_sb_for_writeback(struct writeback_control *wbc, | |
478 | struct inode *inode) | |
479 | { | |
480 | struct super_block *sb = inode->i_sb; | |
481 | ||
482 | /* | |
483 | * Caller must already hold the ref for this | |
484 | */ | |
485 | if (wbc->sync_mode == WB_SYNC_ALL) { | |
486 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); | |
487 | return 0; | |
488 | } | |
489 | ||
490 | spin_lock(&sb_lock); | |
491 | sb->s_count++; | |
492 | if (down_read_trylock(&sb->s_umount)) { | |
493 | if (sb->s_root) { | |
494 | spin_unlock(&sb_lock); | |
495 | return 0; | |
496 | } | |
497 | /* | |
498 | * umounted, drop rwsem again and fall through to failure | |
499 | */ | |
500 | up_read(&sb->s_umount); | |
501 | } | |
502 | ||
503 | sb->s_count--; | |
504 | spin_unlock(&sb_lock); | |
505 | return 1; | |
506 | } | |
507 | ||
508 | static void unpin_sb_for_writeback(struct writeback_control *wbc, | |
509 | struct inode *inode) | |
510 | { | |
511 | struct super_block *sb = inode->i_sb; | |
512 | ||
513 | if (wbc->sync_mode == WB_SYNC_ALL) | |
514 | return; | |
515 | ||
516 | up_read(&sb->s_umount); | |
517 | put_super(sb); | |
518 | } | |
519 | ||
520 | static void writeback_inodes_wb(struct bdi_writeback *wb, | |
521 | struct writeback_control *wbc) | |
1da177e4 | 522 | { |
03ba3782 | 523 | struct super_block *sb = wbc->sb; |
66f3b8e2 | 524 | const int is_blkdev_sb = sb_is_blkdev_sb(sb); |
1da177e4 LT |
525 | const unsigned long start = jiffies; /* livelock avoidance */ |
526 | ||
ae8547b0 | 527 | spin_lock(&inode_lock); |
1da177e4 | 528 | |
03ba3782 JA |
529 | if (!wbc->for_kupdate || list_empty(&wb->b_io)) |
530 | queue_io(wb, wbc->older_than_this); | |
66f3b8e2 | 531 | |
03ba3782 JA |
532 | while (!list_empty(&wb->b_io)) { |
533 | struct inode *inode = list_entry(wb->b_io.prev, | |
1da177e4 | 534 | struct inode, i_list); |
1da177e4 LT |
535 | long pages_skipped; |
536 | ||
66f3b8e2 JA |
537 | /* |
538 | * super block given and doesn't match, skip this inode | |
539 | */ | |
540 | if (sb && sb != inode->i_sb) { | |
541 | redirty_tail(inode); | |
542 | continue; | |
543 | } | |
544 | ||
03ba3782 | 545 | if (!bdi_cap_writeback_dirty(wb->bdi)) { |
9852a0e7 | 546 | redirty_tail(inode); |
66f3b8e2 | 547 | if (is_blkdev_sb) { |
1da177e4 LT |
548 | /* |
549 | * Dirty memory-backed blockdev: the ramdisk | |
550 | * driver does this. Skip just this inode | |
551 | */ | |
552 | continue; | |
553 | } | |
554 | /* | |
555 | * Dirty memory-backed inode against a filesystem other | |
556 | * than the kernel-internal bdev filesystem. Skip the | |
557 | * entire superblock. | |
558 | */ | |
559 | break; | |
560 | } | |
561 | ||
84a89245 | 562 | if (inode->i_state & (I_NEW | I_WILL_FREE)) { |
7ef0d737 NP |
563 | requeue_io(inode); |
564 | continue; | |
565 | } | |
566 | ||
03ba3782 | 567 | if (wbc->nonblocking && bdi_write_congested(wb->bdi)) { |
1da177e4 | 568 | wbc->encountered_congestion = 1; |
66f3b8e2 | 569 | if (!is_blkdev_sb) |
1da177e4 | 570 | break; /* Skip a congested fs */ |
0e0f4fc2 | 571 | requeue_io(inode); |
1da177e4 LT |
572 | continue; /* Skip a congested blockdev */ |
573 | } | |
574 | ||
d2caa3c5 JL |
575 | /* |
576 | * Was this inode dirtied after sync_sb_inodes was called? | |
577 | * This keeps sync from extra jobs and livelock. | |
578 | */ | |
579 | if (inode_dirtied_after(inode, start)) | |
1da177e4 LT |
580 | break; |
581 | ||
03ba3782 JA |
582 | if (pin_sb_for_writeback(wbc, inode)) { |
583 | requeue_io(inode); | |
584 | continue; | |
585 | } | |
1da177e4 | 586 | |
84a89245 | 587 | BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); |
1da177e4 LT |
588 | __iget(inode); |
589 | pages_skipped = wbc->pages_skipped; | |
01c03194 | 590 | writeback_single_inode(inode, wbc); |
03ba3782 | 591 | unpin_sb_for_writeback(wbc, inode); |
1da177e4 LT |
592 | if (wbc->pages_skipped != pages_skipped) { |
593 | /* | |
594 | * writeback is not making progress due to locked | |
595 | * buffers. Skip this inode for now. | |
596 | */ | |
f57b9b7b | 597 | redirty_tail(inode); |
1da177e4 LT |
598 | } |
599 | spin_unlock(&inode_lock); | |
1da177e4 | 600 | iput(inode); |
4ffc8444 | 601 | cond_resched(); |
1da177e4 | 602 | spin_lock(&inode_lock); |
8bc3be27 FW |
603 | if (wbc->nr_to_write <= 0) { |
604 | wbc->more_io = 1; | |
1da177e4 | 605 | break; |
8bc3be27 | 606 | } |
03ba3782 | 607 | if (!list_empty(&wb->b_more_io)) |
8bc3be27 | 608 | wbc->more_io = 1; |
1da177e4 | 609 | } |
38f21977 | 610 | |
66f3b8e2 JA |
611 | spin_unlock(&inode_lock); |
612 | /* Leave any unwritten inodes on b_io */ | |
613 | } | |
614 | ||
03ba3782 JA |
615 | void writeback_inodes_wbc(struct writeback_control *wbc) |
616 | { | |
617 | struct backing_dev_info *bdi = wbc->bdi; | |
618 | ||
619 | writeback_inodes_wb(&bdi->wb, wbc); | |
620 | } | |
621 | ||
66f3b8e2 | 622 | /* |
03ba3782 JA |
623 | * The maximum number of pages to writeout in a single bdi flush/kupdate |
624 | * operation. We do this so we don't hold I_SYNC against an inode for | |
625 | * enormous amounts of time, which would block a userspace task which has | |
626 | * been forced to throttle against that inode. Also, the code reevaluates | |
627 | * the dirty each time it has written this many pages. | |
628 | */ | |
629 | #define MAX_WRITEBACK_PAGES 1024 | |
630 | ||
631 | static inline bool over_bground_thresh(void) | |
632 | { | |
633 | unsigned long background_thresh, dirty_thresh; | |
634 | ||
635 | get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); | |
636 | ||
637 | return (global_page_state(NR_FILE_DIRTY) + | |
638 | global_page_state(NR_UNSTABLE_NFS) >= background_thresh); | |
639 | } | |
640 | ||
641 | /* | |
642 | * Explicit flushing or periodic writeback of "old" data. | |
66f3b8e2 | 643 | * |
03ba3782 JA |
644 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
645 | * dirtying-time in the inode's address_space. So this periodic writeback code | |
646 | * just walks the superblock inode list, writing back any inodes which are | |
647 | * older than a specific point in time. | |
66f3b8e2 | 648 | * |
03ba3782 JA |
649 | * Try to run once per dirty_writeback_interval. But if a writeback event |
650 | * takes longer than a dirty_writeback_interval interval, then leave a | |
651 | * one-second gap. | |
66f3b8e2 | 652 | * |
03ba3782 JA |
653 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
654 | * all dirty pages if they are all attached to "old" mappings. | |
66f3b8e2 | 655 | */ |
03ba3782 JA |
656 | static long wb_writeback(struct bdi_writeback *wb, long nr_pages, |
657 | struct super_block *sb, | |
658 | enum writeback_sync_modes sync_mode, int for_kupdate) | |
66f3b8e2 | 659 | { |
03ba3782 JA |
660 | struct writeback_control wbc = { |
661 | .bdi = wb->bdi, | |
662 | .sb = sb, | |
663 | .sync_mode = sync_mode, | |
664 | .older_than_this = NULL, | |
665 | .for_kupdate = for_kupdate, | |
666 | .range_cyclic = 1, | |
667 | }; | |
668 | unsigned long oldest_jif; | |
669 | long wrote = 0; | |
66f3b8e2 | 670 | |
03ba3782 JA |
671 | if (wbc.for_kupdate) { |
672 | wbc.older_than_this = &oldest_jif; | |
673 | oldest_jif = jiffies - | |
674 | msecs_to_jiffies(dirty_expire_interval * 10); | |
675 | } | |
38f21977 | 676 | |
03ba3782 JA |
677 | for (;;) { |
678 | /* | |
679 | * Don't flush anything for non-integrity writeback where | |
680 | * no nr_pages was given | |
681 | */ | |
682 | if (!for_kupdate && nr_pages <= 0 && sync_mode == WB_SYNC_NONE) | |
683 | break; | |
66f3b8e2 | 684 | |
38f21977 | 685 | /* |
03ba3782 JA |
686 | * If no specific pages were given and this is just a |
687 | * periodic background writeout and we are below the | |
688 | * background dirty threshold, don't do anything | |
38f21977 | 689 | */ |
03ba3782 JA |
690 | if (for_kupdate && nr_pages <= 0 && !over_bground_thresh()) |
691 | break; | |
38f21977 | 692 | |
03ba3782 JA |
693 | wbc.more_io = 0; |
694 | wbc.encountered_congestion = 0; | |
695 | wbc.nr_to_write = MAX_WRITEBACK_PAGES; | |
696 | wbc.pages_skipped = 0; | |
697 | writeback_inodes_wb(wb, &wbc); | |
698 | nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; | |
699 | wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; | |
700 | ||
701 | /* | |
702 | * If we ran out of stuff to write, bail unless more_io got set | |
703 | */ | |
704 | if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) { | |
705 | if (wbc.more_io && !wbc.for_kupdate) | |
38f21977 | 706 | continue; |
03ba3782 JA |
707 | break; |
708 | } | |
709 | } | |
710 | ||
711 | return wrote; | |
712 | } | |
713 | ||
714 | /* | |
715 | * Return the next bdi_work struct that hasn't been processed by this | |
716 | * wb thread yet | |
717 | */ | |
718 | static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi, | |
719 | struct bdi_writeback *wb) | |
720 | { | |
721 | struct bdi_work *work, *ret = NULL; | |
722 | ||
723 | rcu_read_lock(); | |
724 | ||
725 | list_for_each_entry_rcu(work, &bdi->work_list, list) { | |
726 | if (!test_and_clear_bit(wb->nr, &work->seen)) | |
727 | continue; | |
728 | ||
729 | ret = work; | |
730 | break; | |
731 | } | |
732 | ||
733 | rcu_read_unlock(); | |
734 | return ret; | |
735 | } | |
736 | ||
737 | static long wb_check_old_data_flush(struct bdi_writeback *wb) | |
738 | { | |
739 | unsigned long expired; | |
740 | long nr_pages; | |
741 | ||
742 | expired = wb->last_old_flush + | |
743 | msecs_to_jiffies(dirty_writeback_interval * 10); | |
744 | if (time_before(jiffies, expired)) | |
745 | return 0; | |
746 | ||
747 | wb->last_old_flush = jiffies; | |
748 | nr_pages = global_page_state(NR_FILE_DIRTY) + | |
749 | global_page_state(NR_UNSTABLE_NFS) + | |
750 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); | |
751 | ||
752 | if (nr_pages) | |
753 | return wb_writeback(wb, nr_pages, NULL, WB_SYNC_NONE, 1); | |
754 | ||
755 | return 0; | |
756 | } | |
757 | ||
758 | /* | |
759 | * Retrieve work items and do the writeback they describe | |
760 | */ | |
761 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) | |
762 | { | |
763 | struct backing_dev_info *bdi = wb->bdi; | |
764 | struct bdi_work *work; | |
765 | long nr_pages, wrote = 0; | |
766 | ||
767 | while ((work = get_next_work_item(bdi, wb)) != NULL) { | |
768 | enum writeback_sync_modes sync_mode; | |
769 | ||
770 | nr_pages = work->nr_pages; | |
771 | ||
772 | /* | |
773 | * Override sync mode, in case we must wait for completion | |
774 | */ | |
775 | if (force_wait) | |
776 | work->sync_mode = sync_mode = WB_SYNC_ALL; | |
777 | else | |
778 | sync_mode = work->sync_mode; | |
779 | ||
780 | /* | |
781 | * If this isn't a data integrity operation, just notify | |
782 | * that we have seen this work and we are now starting it. | |
783 | */ | |
784 | if (sync_mode == WB_SYNC_NONE) | |
785 | wb_clear_pending(wb, work); | |
786 | ||
787 | wrote += wb_writeback(wb, nr_pages, work->sb, sync_mode, 0); | |
788 | ||
789 | /* | |
790 | * This is a data integrity writeback, so only do the | |
791 | * notification when we have completed the work. | |
792 | */ | |
793 | if (sync_mode == WB_SYNC_ALL) | |
794 | wb_clear_pending(wb, work); | |
795 | } | |
796 | ||
797 | /* | |
798 | * Check for periodic writeback, kupdated() style | |
799 | */ | |
800 | wrote += wb_check_old_data_flush(wb); | |
801 | ||
802 | return wrote; | |
803 | } | |
804 | ||
805 | /* | |
806 | * Handle writeback of dirty data for the device backed by this bdi. Also | |
807 | * wakes up periodically and does kupdated style flushing. | |
808 | */ | |
809 | int bdi_writeback_task(struct bdi_writeback *wb) | |
810 | { | |
811 | unsigned long last_active = jiffies; | |
812 | unsigned long wait_jiffies = -1UL; | |
813 | long pages_written; | |
814 | ||
815 | while (!kthread_should_stop()) { | |
816 | pages_written = wb_do_writeback(wb, 0); | |
817 | ||
818 | if (pages_written) | |
819 | last_active = jiffies; | |
820 | else if (wait_jiffies != -1UL) { | |
821 | unsigned long max_idle; | |
822 | ||
38f21977 | 823 | /* |
03ba3782 JA |
824 | * Longest period of inactivity that we tolerate. If we |
825 | * see dirty data again later, the task will get | |
826 | * recreated automatically. | |
38f21977 | 827 | */ |
03ba3782 JA |
828 | max_idle = max(5UL * 60 * HZ, wait_jiffies); |
829 | if (time_after(jiffies, max_idle + last_active)) | |
830 | break; | |
831 | } | |
832 | ||
833 | wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); | |
834 | set_current_state(TASK_INTERRUPTIBLE); | |
835 | schedule_timeout(wait_jiffies); | |
836 | try_to_freeze(); | |
837 | } | |
838 | ||
839 | return 0; | |
840 | } | |
841 | ||
842 | /* | |
843 | * Schedule writeback for all backing devices. Expensive! If this is a data | |
844 | * integrity operation, writeback will be complete when this returns. If | |
845 | * we are simply called for WB_SYNC_NONE, then writeback will merely be | |
846 | * scheduled to run. | |
847 | */ | |
848 | static void bdi_writeback_all(struct writeback_control *wbc) | |
849 | { | |
850 | const bool must_wait = wbc->sync_mode == WB_SYNC_ALL; | |
851 | struct backing_dev_info *bdi; | |
852 | struct bdi_work *work; | |
853 | LIST_HEAD(list); | |
854 | ||
855 | restart: | |
856 | spin_lock(&bdi_lock); | |
857 | ||
858 | list_for_each_entry(bdi, &bdi_list, bdi_list) { | |
859 | struct bdi_work *work; | |
860 | ||
861 | if (!bdi_has_dirty_io(bdi)) | |
862 | continue; | |
38f21977 | 863 | |
03ba3782 JA |
864 | /* |
865 | * If work allocation fails, do the writes inline. We drop | |
866 | * the lock and restart the list writeout. This should be OK, | |
867 | * since this happens rarely and because the writeout should | |
868 | * eventually make more free memory available. | |
869 | */ | |
870 | work = bdi_alloc_work(wbc); | |
871 | if (!work) { | |
872 | struct writeback_control __wbc; | |
38f21977 | 873 | |
03ba3782 JA |
874 | /* |
875 | * Not a data integrity writeout, just continue | |
876 | */ | |
877 | if (!must_wait) | |
878 | continue; | |
38f21977 | 879 | |
03ba3782 JA |
880 | spin_unlock(&bdi_lock); |
881 | __wbc = *wbc; | |
882 | __wbc.bdi = bdi; | |
883 | writeback_inodes_wbc(&__wbc); | |
884 | goto restart; | |
38f21977 | 885 | } |
03ba3782 JA |
886 | if (must_wait) |
887 | list_add_tail(&work->wait_list, &list); | |
888 | ||
889 | bdi_queue_work(bdi, work); | |
890 | } | |
891 | ||
892 | spin_unlock(&bdi_lock); | |
893 | ||
894 | /* | |
895 | * If this is for WB_SYNC_ALL, wait for pending work to complete | |
896 | * before returning. | |
897 | */ | |
898 | while (!list_empty(&list)) { | |
899 | work = list_entry(list.next, struct bdi_work, wait_list); | |
900 | list_del(&work->wait_list); | |
901 | bdi_wait_on_work_clear(work); | |
902 | call_rcu(&work->rcu_head, bdi_work_free); | |
66f3b8e2 | 903 | } |
1da177e4 LT |
904 | } |
905 | ||
906 | /* | |
03ba3782 JA |
907 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
908 | * the whole world. | |
909 | */ | |
910 | void wakeup_flusher_threads(long nr_pages) | |
911 | { | |
912 | struct writeback_control wbc = { | |
913 | .sync_mode = WB_SYNC_NONE, | |
914 | .older_than_this = NULL, | |
915 | .range_cyclic = 1, | |
916 | }; | |
917 | ||
918 | if (nr_pages == 0) | |
919 | nr_pages = global_page_state(NR_FILE_DIRTY) + | |
920 | global_page_state(NR_UNSTABLE_NFS); | |
921 | wbc.nr_to_write = nr_pages; | |
922 | bdi_writeback_all(&wbc); | |
923 | } | |
924 | ||
925 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) | |
926 | { | |
927 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { | |
928 | struct dentry *dentry; | |
929 | const char *name = "?"; | |
930 | ||
931 | dentry = d_find_alias(inode); | |
932 | if (dentry) { | |
933 | spin_lock(&dentry->d_lock); | |
934 | name = (const char *) dentry->d_name.name; | |
935 | } | |
936 | printk(KERN_DEBUG | |
937 | "%s(%d): dirtied inode %lu (%s) on %s\n", | |
938 | current->comm, task_pid_nr(current), inode->i_ino, | |
939 | name, inode->i_sb->s_id); | |
940 | if (dentry) { | |
941 | spin_unlock(&dentry->d_lock); | |
942 | dput(dentry); | |
943 | } | |
944 | } | |
945 | } | |
946 | ||
947 | /** | |
948 | * __mark_inode_dirty - internal function | |
949 | * @inode: inode to mark | |
950 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) | |
951 | * Mark an inode as dirty. Callers should use mark_inode_dirty or | |
952 | * mark_inode_dirty_sync. | |
1da177e4 | 953 | * |
03ba3782 JA |
954 | * Put the inode on the super block's dirty list. |
955 | * | |
956 | * CAREFUL! We mark it dirty unconditionally, but move it onto the | |
957 | * dirty list only if it is hashed or if it refers to a blockdev. | |
958 | * If it was not hashed, it will never be added to the dirty list | |
959 | * even if it is later hashed, as it will have been marked dirty already. | |
960 | * | |
961 | * In short, make sure you hash any inodes _before_ you start marking | |
962 | * them dirty. | |
1da177e4 | 963 | * |
03ba3782 JA |
964 | * This function *must* be atomic for the I_DIRTY_PAGES case - |
965 | * set_page_dirty() is called under spinlock in several places. | |
1da177e4 | 966 | * |
03ba3782 JA |
967 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
968 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of | |
969 | * the kernel-internal blockdev inode represents the dirtying time of the | |
970 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use | |
971 | * page->mapping->host, so the page-dirtying time is recorded in the internal | |
972 | * blockdev inode. | |
1da177e4 | 973 | */ |
03ba3782 | 974 | void __mark_inode_dirty(struct inode *inode, int flags) |
1da177e4 | 975 | { |
03ba3782 | 976 | struct super_block *sb = inode->i_sb; |
1da177e4 | 977 | |
03ba3782 JA |
978 | /* |
979 | * Don't do this for I_DIRTY_PAGES - that doesn't actually | |
980 | * dirty the inode itself | |
981 | */ | |
982 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
983 | if (sb->s_op->dirty_inode) | |
984 | sb->s_op->dirty_inode(inode); | |
985 | } | |
986 | ||
987 | /* | |
988 | * make sure that changes are seen by all cpus before we test i_state | |
989 | * -- mikulas | |
990 | */ | |
991 | smp_mb(); | |
992 | ||
993 | /* avoid the locking if we can */ | |
994 | if ((inode->i_state & flags) == flags) | |
995 | return; | |
996 | ||
997 | if (unlikely(block_dump)) | |
998 | block_dump___mark_inode_dirty(inode); | |
999 | ||
1000 | spin_lock(&inode_lock); | |
1001 | if ((inode->i_state & flags) != flags) { | |
1002 | const int was_dirty = inode->i_state & I_DIRTY; | |
1003 | ||
1004 | inode->i_state |= flags; | |
1005 | ||
1006 | /* | |
1007 | * If the inode is being synced, just update its dirty state. | |
1008 | * The unlocker will place the inode on the appropriate | |
1009 | * superblock list, based upon its state. | |
1010 | */ | |
1011 | if (inode->i_state & I_SYNC) | |
1012 | goto out; | |
1013 | ||
1014 | /* | |
1015 | * Only add valid (hashed) inodes to the superblock's | |
1016 | * dirty list. Add blockdev inodes as well. | |
1017 | */ | |
1018 | if (!S_ISBLK(inode->i_mode)) { | |
1019 | if (hlist_unhashed(&inode->i_hash)) | |
1020 | goto out; | |
1021 | } | |
1022 | if (inode->i_state & (I_FREEING|I_CLEAR)) | |
1023 | goto out; | |
1024 | ||
1025 | /* | |
1026 | * If the inode was already on b_dirty/b_io/b_more_io, don't | |
1027 | * reposition it (that would break b_dirty time-ordering). | |
1028 | */ | |
1029 | if (!was_dirty) { | |
1030 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; | |
500b067c JA |
1031 | struct backing_dev_info *bdi = wb->bdi; |
1032 | ||
1033 | if (bdi_cap_writeback_dirty(bdi) && | |
1034 | !test_bit(BDI_registered, &bdi->state)) { | |
1035 | WARN_ON(1); | |
1036 | printk(KERN_ERR "bdi-%s not registered\n", | |
1037 | bdi->name); | |
1038 | } | |
03ba3782 JA |
1039 | |
1040 | inode->dirtied_when = jiffies; | |
1041 | list_move(&inode->i_list, &wb->b_dirty); | |
1da177e4 | 1042 | } |
1da177e4 | 1043 | } |
03ba3782 JA |
1044 | out: |
1045 | spin_unlock(&inode_lock); | |
1046 | } | |
1047 | EXPORT_SYMBOL(__mark_inode_dirty); | |
1048 | ||
1049 | /* | |
1050 | * Write out a superblock's list of dirty inodes. A wait will be performed | |
1051 | * upon no inodes, all inodes or the final one, depending upon sync_mode. | |
1052 | * | |
1053 | * If older_than_this is non-NULL, then only write out inodes which | |
1054 | * had their first dirtying at a time earlier than *older_than_this. | |
1055 | * | |
1056 | * If we're a pdlfush thread, then implement pdflush collision avoidance | |
1057 | * against the entire list. | |
1058 | * | |
1059 | * If `bdi' is non-zero then we're being asked to writeback a specific queue. | |
1060 | * This function assumes that the blockdev superblock's inodes are backed by | |
1061 | * a variety of queues, so all inodes are searched. For other superblocks, | |
1062 | * assume that all inodes are backed by the same queue. | |
1063 | * | |
1064 | * The inodes to be written are parked on bdi->b_io. They are moved back onto | |
1065 | * bdi->b_dirty as they are selected for writing. This way, none can be missed | |
1066 | * on the writer throttling path, and we get decent balancing between many | |
1067 | * throttled threads: we don't want them all piling up on inode_sync_wait. | |
1068 | */ | |
1069 | static void wait_sb_inodes(struct writeback_control *wbc) | |
1070 | { | |
1071 | struct inode *inode, *old_inode = NULL; | |
1072 | ||
1073 | /* | |
1074 | * We need to be protected against the filesystem going from | |
1075 | * r/o to r/w or vice versa. | |
1076 | */ | |
1077 | WARN_ON(!rwsem_is_locked(&wbc->sb->s_umount)); | |
1078 | ||
1079 | spin_lock(&inode_lock); | |
1080 | ||
1081 | /* | |
1082 | * Data integrity sync. Must wait for all pages under writeback, | |
1083 | * because there may have been pages dirtied before our sync | |
1084 | * call, but which had writeout started before we write it out. | |
1085 | * In which case, the inode may not be on the dirty list, but | |
1086 | * we still have to wait for that writeout. | |
1087 | */ | |
1088 | list_for_each_entry(inode, &wbc->sb->s_inodes, i_sb_list) { | |
1089 | struct address_space *mapping; | |
1090 | ||
1091 | if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) | |
1092 | continue; | |
1093 | mapping = inode->i_mapping; | |
1094 | if (mapping->nrpages == 0) | |
1095 | continue; | |
1096 | __iget(inode); | |
1097 | spin_unlock(&inode_lock); | |
1098 | /* | |
1099 | * We hold a reference to 'inode' so it couldn't have | |
1100 | * been removed from s_inodes list while we dropped the | |
1101 | * inode_lock. We cannot iput the inode now as we can | |
1102 | * be holding the last reference and we cannot iput it | |
1103 | * under inode_lock. So we keep the reference and iput | |
1104 | * it later. | |
1105 | */ | |
1106 | iput(old_inode); | |
1107 | old_inode = inode; | |
1108 | ||
1109 | filemap_fdatawait(mapping); | |
1110 | ||
1111 | cond_resched(); | |
1112 | ||
1113 | spin_lock(&inode_lock); | |
1114 | } | |
1115 | spin_unlock(&inode_lock); | |
1116 | iput(old_inode); | |
1da177e4 LT |
1117 | } |
1118 | ||
d8a8559c JA |
1119 | /** |
1120 | * writeback_inodes_sb - writeback dirty inodes from given super_block | |
1121 | * @sb: the superblock | |
1da177e4 | 1122 | * |
d8a8559c JA |
1123 | * Start writeback on some inodes on this super_block. No guarantees are made |
1124 | * on how many (if any) will be written, and this function does not wait | |
1125 | * for IO completion of submitted IO. The number of pages submitted is | |
1126 | * returned. | |
1da177e4 | 1127 | */ |
d8a8559c | 1128 | long writeback_inodes_sb(struct super_block *sb) |
1da177e4 LT |
1129 | { |
1130 | struct writeback_control wbc = { | |
03ba3782 | 1131 | .sb = sb, |
d8a8559c | 1132 | .sync_mode = WB_SYNC_NONE, |
111ebb6e OH |
1133 | .range_start = 0, |
1134 | .range_end = LLONG_MAX, | |
1da177e4 | 1135 | }; |
d8a8559c JA |
1136 | unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); |
1137 | unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); | |
1138 | long nr_to_write; | |
1da177e4 | 1139 | |
d8a8559c | 1140 | nr_to_write = nr_dirty + nr_unstable + |
38f21977 | 1141 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); |
38f21977 | 1142 | |
d8a8559c | 1143 | wbc.nr_to_write = nr_to_write; |
03ba3782 | 1144 | bdi_writeback_all(&wbc); |
d8a8559c JA |
1145 | return nr_to_write - wbc.nr_to_write; |
1146 | } | |
1147 | EXPORT_SYMBOL(writeback_inodes_sb); | |
1148 | ||
1149 | /** | |
1150 | * sync_inodes_sb - sync sb inode pages | |
1151 | * @sb: the superblock | |
1152 | * | |
1153 | * This function writes and waits on any dirty inode belonging to this | |
1154 | * super_block. The number of pages synced is returned. | |
1155 | */ | |
1156 | long sync_inodes_sb(struct super_block *sb) | |
1157 | { | |
1158 | struct writeback_control wbc = { | |
03ba3782 | 1159 | .sb = sb, |
d8a8559c JA |
1160 | .sync_mode = WB_SYNC_ALL, |
1161 | .range_start = 0, | |
1162 | .range_end = LLONG_MAX, | |
1163 | }; | |
1164 | long nr_to_write = LONG_MAX; /* doesn't actually matter */ | |
1165 | ||
1166 | wbc.nr_to_write = nr_to_write; | |
03ba3782 JA |
1167 | bdi_writeback_all(&wbc); |
1168 | wait_sb_inodes(&wbc); | |
d8a8559c | 1169 | return nr_to_write - wbc.nr_to_write; |
1da177e4 | 1170 | } |
d8a8559c | 1171 | EXPORT_SYMBOL(sync_inodes_sb); |
1da177e4 | 1172 | |
1da177e4 | 1173 | /** |
7f04c26d AA |
1174 | * write_inode_now - write an inode to disk |
1175 | * @inode: inode to write to disk | |
1176 | * @sync: whether the write should be synchronous or not | |
1177 | * | |
1178 | * This function commits an inode to disk immediately if it is dirty. This is | |
1179 | * primarily needed by knfsd. | |
1da177e4 | 1180 | * |
7f04c26d | 1181 | * The caller must either have a ref on the inode or must have set I_WILL_FREE. |
1da177e4 | 1182 | */ |
1da177e4 LT |
1183 | int write_inode_now(struct inode *inode, int sync) |
1184 | { | |
1185 | int ret; | |
1186 | struct writeback_control wbc = { | |
1187 | .nr_to_write = LONG_MAX, | |
18914b18 | 1188 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
111ebb6e OH |
1189 | .range_start = 0, |
1190 | .range_end = LLONG_MAX, | |
1da177e4 LT |
1191 | }; |
1192 | ||
1193 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) | |
49364ce2 | 1194 | wbc.nr_to_write = 0; |
1da177e4 LT |
1195 | |
1196 | might_sleep(); | |
1197 | spin_lock(&inode_lock); | |
01c03194 | 1198 | ret = writeback_single_inode(inode, &wbc); |
1da177e4 LT |
1199 | spin_unlock(&inode_lock); |
1200 | if (sync) | |
1c0eeaf5 | 1201 | inode_sync_wait(inode); |
1da177e4 LT |
1202 | return ret; |
1203 | } | |
1204 | EXPORT_SYMBOL(write_inode_now); | |
1205 | ||
1206 | /** | |
1207 | * sync_inode - write an inode and its pages to disk. | |
1208 | * @inode: the inode to sync | |
1209 | * @wbc: controls the writeback mode | |
1210 | * | |
1211 | * sync_inode() will write an inode and its pages to disk. It will also | |
1212 | * correctly update the inode on its superblock's dirty inode lists and will | |
1213 | * update inode->i_state. | |
1214 | * | |
1215 | * The caller must have a ref on the inode. | |
1216 | */ | |
1217 | int sync_inode(struct inode *inode, struct writeback_control *wbc) | |
1218 | { | |
1219 | int ret; | |
1220 | ||
1221 | spin_lock(&inode_lock); | |
01c03194 | 1222 | ret = writeback_single_inode(inode, wbc); |
1da177e4 LT |
1223 | spin_unlock(&inode_lock); |
1224 | return ret; | |
1225 | } | |
1226 | EXPORT_SYMBOL(sync_inode); |