Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * fs/fs-writeback.c | |
3 | * | |
4 | * Copyright (C) 2002, Linus Torvalds. | |
5 | * | |
6 | * Contains all the functions related to writing back and waiting | |
7 | * upon dirty inodes against superblocks, and writing back dirty | |
8 | * pages against inodes. ie: data writeback. Writeout of the | |
9 | * inode itself is not handled here. | |
10 | * | |
e1f8e874 | 11 | * 10Apr2002 Andrew Morton |
1da177e4 LT |
12 | * Split out of fs/inode.c |
13 | * Additions for address_space-based writeback | |
14 | */ | |
15 | ||
16 | #include <linux/kernel.h> | |
630d9c47 | 17 | #include <linux/export.h> |
1da177e4 | 18 | #include <linux/spinlock.h> |
5a0e3ad6 | 19 | #include <linux/slab.h> |
1da177e4 LT |
20 | #include <linux/sched.h> |
21 | #include <linux/fs.h> | |
22 | #include <linux/mm.h> | |
bc31b86a | 23 | #include <linux/pagemap.h> |
03ba3782 | 24 | #include <linux/kthread.h> |
1da177e4 LT |
25 | #include <linux/writeback.h> |
26 | #include <linux/blkdev.h> | |
27 | #include <linux/backing-dev.h> | |
455b2864 | 28 | #include <linux/tracepoint.h> |
719ea2fb | 29 | #include <linux/device.h> |
07f3f05c | 30 | #include "internal.h" |
1da177e4 | 31 | |
bc31b86a WF |
32 | /* |
33 | * 4MB minimal write chunk size | |
34 | */ | |
35 | #define MIN_WRITEBACK_PAGES (4096UL >> (PAGE_CACHE_SHIFT - 10)) | |
36 | ||
c4a77a6c JA |
37 | /* |
38 | * Passed into wb_writeback(), essentially a subset of writeback_control | |
39 | */ | |
83ba7b07 | 40 | struct wb_writeback_work { |
c4a77a6c JA |
41 | long nr_pages; |
42 | struct super_block *sb; | |
c4a391b5 JK |
43 | /* |
44 | * Write only inodes dirtied before this time. Don't forget to set | |
45 | * older_than_this_is_set when you set this. | |
46 | */ | |
47 | unsigned long older_than_this; | |
c4a77a6c | 48 | enum writeback_sync_modes sync_mode; |
6e6938b6 | 49 | unsigned int tagged_writepages:1; |
52957fe1 HS |
50 | unsigned int for_kupdate:1; |
51 | unsigned int range_cyclic:1; | |
52 | unsigned int for_background:1; | |
7747bd4b | 53 | unsigned int for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ |
c4a391b5 | 54 | unsigned int older_than_this_is_set:1; |
0e175a18 | 55 | enum wb_reason reason; /* why was writeback initiated? */ |
c4a77a6c | 56 | |
8010c3b6 | 57 | struct list_head list; /* pending work list */ |
83ba7b07 | 58 | struct completion *done; /* set if the caller waits */ |
03ba3782 JA |
59 | }; |
60 | ||
f11b00f3 AB |
61 | /** |
62 | * writeback_in_progress - determine whether there is writeback in progress | |
63 | * @bdi: the device's backing_dev_info structure. | |
64 | * | |
03ba3782 JA |
65 | * Determine whether there is writeback waiting to be handled against a |
66 | * backing device. | |
f11b00f3 AB |
67 | */ |
68 | int writeback_in_progress(struct backing_dev_info *bdi) | |
69 | { | |
81d73a32 | 70 | return test_bit(BDI_writeback_running, &bdi->state); |
f11b00f3 | 71 | } |
00d4e736 | 72 | EXPORT_SYMBOL(writeback_in_progress); |
f11b00f3 | 73 | |
692ebd17 JK |
74 | static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) |
75 | { | |
76 | struct super_block *sb = inode->i_sb; | |
692ebd17 | 77 | |
a8855990 | 78 | if (sb_is_blkdev_sb(sb)) |
aaead25b CH |
79 | return inode->i_mapping->backing_dev_info; |
80 | ||
81 | return sb->s_bdi; | |
692ebd17 JK |
82 | } |
83 | ||
7ccf19a8 NP |
84 | static inline struct inode *wb_inode(struct list_head *head) |
85 | { | |
86 | return list_entry(head, struct inode, i_wb_list); | |
87 | } | |
88 | ||
15eb77a0 WF |
89 | /* |
90 | * Include the creation of the trace points after defining the | |
91 | * wb_writeback_work structure and inline functions so that the definition | |
92 | * remains local to this file. | |
93 | */ | |
94 | #define CREATE_TRACE_POINTS | |
95 | #include <trace/events/writeback.h> | |
96 | ||
6585027a JK |
97 | static void bdi_queue_work(struct backing_dev_info *bdi, |
98 | struct wb_writeback_work *work) | |
99 | { | |
100 | trace_writeback_queue(bdi, work); | |
101 | ||
102 | spin_lock_bh(&bdi->wb_lock); | |
103 | list_add_tail(&work->list, &bdi->work_list); | |
6467716a | 104 | spin_unlock_bh(&bdi->wb_lock); |
839a8e86 TH |
105 | |
106 | mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); | |
1da177e4 LT |
107 | } |
108 | ||
83ba7b07 CH |
109 | static void |
110 | __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, | |
0e175a18 | 111 | bool range_cyclic, enum wb_reason reason) |
1da177e4 | 112 | { |
83ba7b07 | 113 | struct wb_writeback_work *work; |
03ba3782 | 114 | |
bcddc3f0 JA |
115 | /* |
116 | * This is WB_SYNC_NONE writeback, so if allocation fails just | |
117 | * wakeup the thread for old dirty data writeback | |
118 | */ | |
83ba7b07 CH |
119 | work = kzalloc(sizeof(*work), GFP_ATOMIC); |
120 | if (!work) { | |
839a8e86 TH |
121 | trace_writeback_nowork(bdi); |
122 | mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); | |
83ba7b07 | 123 | return; |
bcddc3f0 | 124 | } |
03ba3782 | 125 | |
83ba7b07 CH |
126 | work->sync_mode = WB_SYNC_NONE; |
127 | work->nr_pages = nr_pages; | |
128 | work->range_cyclic = range_cyclic; | |
0e175a18 | 129 | work->reason = reason; |
03ba3782 | 130 | |
83ba7b07 | 131 | bdi_queue_work(bdi, work); |
b6e51316 JA |
132 | } |
133 | ||
134 | /** | |
135 | * bdi_start_writeback - start writeback | |
136 | * @bdi: the backing device to write from | |
137 | * @nr_pages: the number of pages to write | |
786228ab | 138 | * @reason: reason why some writeback work was initiated |
b6e51316 JA |
139 | * |
140 | * Description: | |
141 | * This does WB_SYNC_NONE opportunistic writeback. The IO is only | |
25985edc | 142 | * started when this function returns, we make no guarantees on |
0e3c9a22 | 143 | * completion. Caller need not hold sb s_umount semaphore. |
b6e51316 JA |
144 | * |
145 | */ | |
0e175a18 CW |
146 | void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, |
147 | enum wb_reason reason) | |
b6e51316 | 148 | { |
0e175a18 | 149 | __bdi_start_writeback(bdi, nr_pages, true, reason); |
c5444198 | 150 | } |
d3ddec76 | 151 | |
c5444198 CH |
152 | /** |
153 | * bdi_start_background_writeback - start background writeback | |
154 | * @bdi: the backing device to write from | |
155 | * | |
156 | * Description: | |
6585027a JK |
157 | * This makes sure WB_SYNC_NONE background writeback happens. When |
158 | * this function returns, it is only guaranteed that for given BDI | |
159 | * some IO is happening if we are over background dirty threshold. | |
160 | * Caller need not hold sb s_umount semaphore. | |
c5444198 CH |
161 | */ |
162 | void bdi_start_background_writeback(struct backing_dev_info *bdi) | |
163 | { | |
6585027a JK |
164 | /* |
165 | * We just wake up the flusher thread. It will perform background | |
166 | * writeback as soon as there is no other work to do. | |
167 | */ | |
71927e84 | 168 | trace_writeback_wake_background(bdi); |
839a8e86 | 169 | mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); |
1da177e4 LT |
170 | } |
171 | ||
a66979ab DC |
172 | /* |
173 | * Remove the inode from the writeback list it is on. | |
174 | */ | |
175 | void inode_wb_list_del(struct inode *inode) | |
176 | { | |
f758eeab CH |
177 | struct backing_dev_info *bdi = inode_to_bdi(inode); |
178 | ||
179 | spin_lock(&bdi->wb.list_lock); | |
a66979ab | 180 | list_del_init(&inode->i_wb_list); |
f758eeab | 181 | spin_unlock(&bdi->wb.list_lock); |
a66979ab DC |
182 | } |
183 | ||
6610a0bc AM |
184 | /* |
185 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the | |
186 | * furthest end of its superblock's dirty-inode list. | |
187 | * | |
188 | * Before stamping the inode's ->dirtied_when, we check to see whether it is | |
66f3b8e2 | 189 | * already the most-recently-dirtied inode on the b_dirty list. If that is |
6610a0bc AM |
190 | * the case then the inode must have been redirtied while it was being written |
191 | * out and we don't reset its dirtied_when. | |
192 | */ | |
f758eeab | 193 | static void redirty_tail(struct inode *inode, struct bdi_writeback *wb) |
6610a0bc | 194 | { |
f758eeab | 195 | assert_spin_locked(&wb->list_lock); |
03ba3782 | 196 | if (!list_empty(&wb->b_dirty)) { |
66f3b8e2 | 197 | struct inode *tail; |
6610a0bc | 198 | |
7ccf19a8 | 199 | tail = wb_inode(wb->b_dirty.next); |
66f3b8e2 | 200 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
6610a0bc AM |
201 | inode->dirtied_when = jiffies; |
202 | } | |
7ccf19a8 | 203 | list_move(&inode->i_wb_list, &wb->b_dirty); |
6610a0bc AM |
204 | } |
205 | ||
c986d1e2 | 206 | /* |
66f3b8e2 | 207 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
c986d1e2 | 208 | */ |
f758eeab | 209 | static void requeue_io(struct inode *inode, struct bdi_writeback *wb) |
c986d1e2 | 210 | { |
f758eeab | 211 | assert_spin_locked(&wb->list_lock); |
7ccf19a8 | 212 | list_move(&inode->i_wb_list, &wb->b_more_io); |
c986d1e2 AM |
213 | } |
214 | ||
1c0eeaf5 JE |
215 | static void inode_sync_complete(struct inode *inode) |
216 | { | |
365b94ae | 217 | inode->i_state &= ~I_SYNC; |
4eff96dd JK |
218 | /* If inode is clean an unused, put it into LRU now... */ |
219 | inode_add_lru(inode); | |
365b94ae | 220 | /* Waiters must see I_SYNC cleared before being woken up */ |
1c0eeaf5 JE |
221 | smp_mb(); |
222 | wake_up_bit(&inode->i_state, __I_SYNC); | |
223 | } | |
224 | ||
d2caa3c5 JL |
225 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
226 | { | |
227 | bool ret = time_after(inode->dirtied_when, t); | |
228 | #ifndef CONFIG_64BIT | |
229 | /* | |
230 | * For inodes being constantly redirtied, dirtied_when can get stuck. | |
231 | * It _appears_ to be in the future, but is actually in distant past. | |
232 | * This test is necessary to prevent such wrapped-around relative times | |
5b0830cb | 233 | * from permanently stopping the whole bdi writeback. |
d2caa3c5 JL |
234 | */ |
235 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); | |
236 | #endif | |
237 | return ret; | |
238 | } | |
239 | ||
2c136579 | 240 | /* |
0e2f2b23 | 241 | * Move expired (dirtied before work->older_than_this) dirty inodes from |
697e6fed | 242 | * @delaying_queue to @dispatch_queue. |
2c136579 | 243 | */ |
e84d0a4f | 244 | static int move_expired_inodes(struct list_head *delaying_queue, |
2c136579 | 245 | struct list_head *dispatch_queue, |
ad4e38dd | 246 | struct wb_writeback_work *work) |
2c136579 | 247 | { |
5c03449d SL |
248 | LIST_HEAD(tmp); |
249 | struct list_head *pos, *node; | |
cf137307 | 250 | struct super_block *sb = NULL; |
5c03449d | 251 | struct inode *inode; |
cf137307 | 252 | int do_sb_sort = 0; |
e84d0a4f | 253 | int moved = 0; |
5c03449d | 254 | |
c4a391b5 | 255 | WARN_ON_ONCE(!work->older_than_this_is_set); |
2c136579 | 256 | while (!list_empty(delaying_queue)) { |
7ccf19a8 | 257 | inode = wb_inode(delaying_queue->prev); |
c4a391b5 | 258 | if (inode_dirtied_after(inode, work->older_than_this)) |
2c136579 | 259 | break; |
a8855990 JK |
260 | list_move(&inode->i_wb_list, &tmp); |
261 | moved++; | |
262 | if (sb_is_blkdev_sb(inode->i_sb)) | |
263 | continue; | |
cf137307 JA |
264 | if (sb && sb != inode->i_sb) |
265 | do_sb_sort = 1; | |
266 | sb = inode->i_sb; | |
5c03449d SL |
267 | } |
268 | ||
cf137307 JA |
269 | /* just one sb in list, splice to dispatch_queue and we're done */ |
270 | if (!do_sb_sort) { | |
271 | list_splice(&tmp, dispatch_queue); | |
e84d0a4f | 272 | goto out; |
cf137307 JA |
273 | } |
274 | ||
5c03449d SL |
275 | /* Move inodes from one superblock together */ |
276 | while (!list_empty(&tmp)) { | |
7ccf19a8 | 277 | sb = wb_inode(tmp.prev)->i_sb; |
5c03449d | 278 | list_for_each_prev_safe(pos, node, &tmp) { |
7ccf19a8 | 279 | inode = wb_inode(pos); |
5c03449d | 280 | if (inode->i_sb == sb) |
7ccf19a8 | 281 | list_move(&inode->i_wb_list, dispatch_queue); |
5c03449d | 282 | } |
2c136579 | 283 | } |
e84d0a4f WF |
284 | out: |
285 | return moved; | |
2c136579 FW |
286 | } |
287 | ||
288 | /* | |
289 | * Queue all expired dirty inodes for io, eldest first. | |
4ea879b9 WF |
290 | * Before |
291 | * newly dirtied b_dirty b_io b_more_io | |
292 | * =============> gf edc BA | |
293 | * After | |
294 | * newly dirtied b_dirty b_io b_more_io | |
295 | * =============> g fBAedc | |
296 | * | | |
297 | * +--> dequeue for IO | |
2c136579 | 298 | */ |
ad4e38dd | 299 | static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work) |
66f3b8e2 | 300 | { |
e84d0a4f | 301 | int moved; |
f758eeab | 302 | assert_spin_locked(&wb->list_lock); |
4ea879b9 | 303 | list_splice_init(&wb->b_more_io, &wb->b_io); |
ad4e38dd CW |
304 | moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, work); |
305 | trace_writeback_queue_io(wb, work, moved); | |
66f3b8e2 JA |
306 | } |
307 | ||
a9185b41 | 308 | static int write_inode(struct inode *inode, struct writeback_control *wbc) |
08d8e974 | 309 | { |
9fb0a7da TH |
310 | int ret; |
311 | ||
312 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) { | |
313 | trace_writeback_write_inode_start(inode, wbc); | |
314 | ret = inode->i_sb->s_op->write_inode(inode, wbc); | |
315 | trace_writeback_write_inode(inode, wbc); | |
316 | return ret; | |
317 | } | |
03ba3782 | 318 | return 0; |
08d8e974 | 319 | } |
08d8e974 | 320 | |
1da177e4 | 321 | /* |
169ebd90 JK |
322 | * Wait for writeback on an inode to complete. Called with i_lock held. |
323 | * Caller must make sure inode cannot go away when we drop i_lock. | |
01c03194 | 324 | */ |
169ebd90 JK |
325 | static void __inode_wait_for_writeback(struct inode *inode) |
326 | __releases(inode->i_lock) | |
327 | __acquires(inode->i_lock) | |
01c03194 CH |
328 | { |
329 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); | |
330 | wait_queue_head_t *wqh; | |
331 | ||
332 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
250df6ed DC |
333 | while (inode->i_state & I_SYNC) { |
334 | spin_unlock(&inode->i_lock); | |
01c03194 | 335 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
250df6ed | 336 | spin_lock(&inode->i_lock); |
58a9d3d8 | 337 | } |
01c03194 CH |
338 | } |
339 | ||
169ebd90 JK |
340 | /* |
341 | * Wait for writeback on an inode to complete. Caller must have inode pinned. | |
342 | */ | |
343 | void inode_wait_for_writeback(struct inode *inode) | |
344 | { | |
345 | spin_lock(&inode->i_lock); | |
346 | __inode_wait_for_writeback(inode); | |
347 | spin_unlock(&inode->i_lock); | |
348 | } | |
349 | ||
350 | /* | |
351 | * Sleep until I_SYNC is cleared. This function must be called with i_lock | |
352 | * held and drops it. It is aimed for callers not holding any inode reference | |
353 | * so once i_lock is dropped, inode can go away. | |
354 | */ | |
355 | static void inode_sleep_on_writeback(struct inode *inode) | |
356 | __releases(inode->i_lock) | |
357 | { | |
358 | DEFINE_WAIT(wait); | |
359 | wait_queue_head_t *wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
360 | int sleep; | |
361 | ||
362 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
363 | sleep = inode->i_state & I_SYNC; | |
364 | spin_unlock(&inode->i_lock); | |
365 | if (sleep) | |
366 | schedule(); | |
367 | finish_wait(wqh, &wait); | |
368 | } | |
369 | ||
ccb26b5a JK |
370 | /* |
371 | * Find proper writeback list for the inode depending on its current state and | |
372 | * possibly also change of its state while we were doing writeback. Here we | |
373 | * handle things such as livelock prevention or fairness of writeback among | |
374 | * inodes. This function can be called only by flusher thread - noone else | |
375 | * processes all inodes in writeback lists and requeueing inodes behind flusher | |
376 | * thread's back can have unexpected consequences. | |
377 | */ | |
378 | static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, | |
379 | struct writeback_control *wbc) | |
380 | { | |
381 | if (inode->i_state & I_FREEING) | |
382 | return; | |
383 | ||
384 | /* | |
385 | * Sync livelock prevention. Each inode is tagged and synced in one | |
386 | * shot. If still dirty, it will be redirty_tail()'ed below. Update | |
387 | * the dirty time to prevent enqueue and sync it again. | |
388 | */ | |
389 | if ((inode->i_state & I_DIRTY) && | |
390 | (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)) | |
391 | inode->dirtied_when = jiffies; | |
392 | ||
4f8ad655 JK |
393 | if (wbc->pages_skipped) { |
394 | /* | |
395 | * writeback is not making progress due to locked | |
396 | * buffers. Skip this inode for now. | |
397 | */ | |
398 | redirty_tail(inode, wb); | |
399 | return; | |
400 | } | |
401 | ||
ccb26b5a JK |
402 | if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) { |
403 | /* | |
404 | * We didn't write back all the pages. nfs_writepages() | |
405 | * sometimes bales out without doing anything. | |
406 | */ | |
407 | if (wbc->nr_to_write <= 0) { | |
408 | /* Slice used up. Queue for next turn. */ | |
409 | requeue_io(inode, wb); | |
410 | } else { | |
411 | /* | |
412 | * Writeback blocked by something other than | |
413 | * congestion. Delay the inode for some time to | |
414 | * avoid spinning on the CPU (100% iowait) | |
415 | * retrying writeback of the dirty page/inode | |
416 | * that cannot be performed immediately. | |
417 | */ | |
418 | redirty_tail(inode, wb); | |
419 | } | |
420 | } else if (inode->i_state & I_DIRTY) { | |
421 | /* | |
422 | * Filesystems can dirty the inode during writeback operations, | |
423 | * such as delayed allocation during submission or metadata | |
424 | * updates after data IO completion. | |
425 | */ | |
426 | redirty_tail(inode, wb); | |
427 | } else { | |
428 | /* The inode is clean. Remove from writeback lists. */ | |
429 | list_del_init(&inode->i_wb_list); | |
430 | } | |
431 | } | |
432 | ||
01c03194 | 433 | /* |
4f8ad655 JK |
434 | * Write out an inode and its dirty pages. Do not update the writeback list |
435 | * linkage. That is left to the caller. The caller is also responsible for | |
436 | * setting I_SYNC flag and calling inode_sync_complete() to clear it. | |
1da177e4 LT |
437 | */ |
438 | static int | |
cd8ed2a4 | 439 | __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
1da177e4 | 440 | { |
1da177e4 | 441 | struct address_space *mapping = inode->i_mapping; |
251d6a47 | 442 | long nr_to_write = wbc->nr_to_write; |
01c03194 | 443 | unsigned dirty; |
1da177e4 LT |
444 | int ret; |
445 | ||
4f8ad655 | 446 | WARN_ON(!(inode->i_state & I_SYNC)); |
1da177e4 | 447 | |
9fb0a7da TH |
448 | trace_writeback_single_inode_start(inode, wbc, nr_to_write); |
449 | ||
1da177e4 LT |
450 | ret = do_writepages(mapping, wbc); |
451 | ||
26821ed4 CH |
452 | /* |
453 | * Make sure to wait on the data before writing out the metadata. | |
454 | * This is important for filesystems that modify metadata on data | |
7747bd4b DC |
455 | * I/O completion. We don't do it for sync(2) writeback because it has a |
456 | * separate, external IO completion path and ->sync_fs for guaranteeing | |
457 | * inode metadata is written back correctly. | |
26821ed4 | 458 | */ |
7747bd4b | 459 | if (wbc->sync_mode == WB_SYNC_ALL && !wbc->for_sync) { |
26821ed4 | 460 | int err = filemap_fdatawait(mapping); |
1da177e4 LT |
461 | if (ret == 0) |
462 | ret = err; | |
463 | } | |
464 | ||
5547e8aa DM |
465 | /* |
466 | * Some filesystems may redirty the inode during the writeback | |
467 | * due to delalloc, clear dirty metadata flags right before | |
468 | * write_inode() | |
469 | */ | |
250df6ed | 470 | spin_lock(&inode->i_lock); |
6290be1c JK |
471 | /* Clear I_DIRTY_PAGES if we've written out all dirty pages */ |
472 | if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) | |
473 | inode->i_state &= ~I_DIRTY_PAGES; | |
5547e8aa DM |
474 | dirty = inode->i_state & I_DIRTY; |
475 | inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC); | |
250df6ed | 476 | spin_unlock(&inode->i_lock); |
26821ed4 CH |
477 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
478 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
a9185b41 | 479 | int err = write_inode(inode, wbc); |
1da177e4 LT |
480 | if (ret == 0) |
481 | ret = err; | |
482 | } | |
4f8ad655 JK |
483 | trace_writeback_single_inode(inode, wbc, nr_to_write); |
484 | return ret; | |
485 | } | |
486 | ||
487 | /* | |
488 | * Write out an inode's dirty pages. Either the caller has an active reference | |
489 | * on the inode or the inode has I_WILL_FREE set. | |
490 | * | |
491 | * This function is designed to be called for writing back one inode which | |
492 | * we go e.g. from filesystem. Flusher thread uses __writeback_single_inode() | |
493 | * and does more profound writeback list handling in writeback_sb_inodes(). | |
494 | */ | |
495 | static int | |
496 | writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, | |
497 | struct writeback_control *wbc) | |
498 | { | |
499 | int ret = 0; | |
500 | ||
501 | spin_lock(&inode->i_lock); | |
502 | if (!atomic_read(&inode->i_count)) | |
503 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); | |
504 | else | |
505 | WARN_ON(inode->i_state & I_WILL_FREE); | |
506 | ||
507 | if (inode->i_state & I_SYNC) { | |
508 | if (wbc->sync_mode != WB_SYNC_ALL) | |
509 | goto out; | |
510 | /* | |
169ebd90 JK |
511 | * It's a data-integrity sync. We must wait. Since callers hold |
512 | * inode reference or inode has I_WILL_FREE set, it cannot go | |
513 | * away under us. | |
4f8ad655 | 514 | */ |
169ebd90 | 515 | __inode_wait_for_writeback(inode); |
4f8ad655 JK |
516 | } |
517 | WARN_ON(inode->i_state & I_SYNC); | |
518 | /* | |
f9b0e058 JK |
519 | * Skip inode if it is clean and we have no outstanding writeback in |
520 | * WB_SYNC_ALL mode. We don't want to mess with writeback lists in this | |
521 | * function since flusher thread may be doing for example sync in | |
522 | * parallel and if we move the inode, it could get skipped. So here we | |
523 | * make sure inode is on some writeback list and leave it there unless | |
524 | * we have completely cleaned the inode. | |
4f8ad655 | 525 | */ |
f9b0e058 JK |
526 | if (!(inode->i_state & I_DIRTY) && |
527 | (wbc->sync_mode != WB_SYNC_ALL || | |
528 | !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))) | |
4f8ad655 JK |
529 | goto out; |
530 | inode->i_state |= I_SYNC; | |
531 | spin_unlock(&inode->i_lock); | |
532 | ||
cd8ed2a4 | 533 | ret = __writeback_single_inode(inode, wbc); |
1da177e4 | 534 | |
f758eeab | 535 | spin_lock(&wb->list_lock); |
250df6ed | 536 | spin_lock(&inode->i_lock); |
4f8ad655 JK |
537 | /* |
538 | * If inode is clean, remove it from writeback lists. Otherwise don't | |
539 | * touch it. See comment above for explanation. | |
540 | */ | |
541 | if (!(inode->i_state & I_DIRTY)) | |
542 | list_del_init(&inode->i_wb_list); | |
543 | spin_unlock(&wb->list_lock); | |
1c0eeaf5 | 544 | inode_sync_complete(inode); |
4f8ad655 JK |
545 | out: |
546 | spin_unlock(&inode->i_lock); | |
1da177e4 LT |
547 | return ret; |
548 | } | |
549 | ||
1a12d8bd WF |
550 | static long writeback_chunk_size(struct backing_dev_info *bdi, |
551 | struct wb_writeback_work *work) | |
d46db3d5 WF |
552 | { |
553 | long pages; | |
554 | ||
555 | /* | |
556 | * WB_SYNC_ALL mode does livelock avoidance by syncing dirty | |
557 | * inodes/pages in one big loop. Setting wbc.nr_to_write=LONG_MAX | |
558 | * here avoids calling into writeback_inodes_wb() more than once. | |
559 | * | |
560 | * The intended call sequence for WB_SYNC_ALL writeback is: | |
561 | * | |
562 | * wb_writeback() | |
563 | * writeback_sb_inodes() <== called only once | |
564 | * write_cache_pages() <== called once for each inode | |
565 | * (quickly) tag currently dirty pages | |
566 | * (maybe slowly) sync all tagged pages | |
567 | */ | |
568 | if (work->sync_mode == WB_SYNC_ALL || work->tagged_writepages) | |
569 | pages = LONG_MAX; | |
1a12d8bd WF |
570 | else { |
571 | pages = min(bdi->avg_write_bandwidth / 2, | |
572 | global_dirty_limit / DIRTY_SCOPE); | |
573 | pages = min(pages, work->nr_pages); | |
574 | pages = round_down(pages + MIN_WRITEBACK_PAGES, | |
575 | MIN_WRITEBACK_PAGES); | |
576 | } | |
d46db3d5 WF |
577 | |
578 | return pages; | |
579 | } | |
580 | ||
f11c9c5c ES |
581 | /* |
582 | * Write a portion of b_io inodes which belong to @sb. | |
edadfb10 | 583 | * |
d46db3d5 | 584 | * Return the number of pages and/or inodes written. |
f11c9c5c | 585 | */ |
d46db3d5 WF |
586 | static long writeback_sb_inodes(struct super_block *sb, |
587 | struct bdi_writeback *wb, | |
588 | struct wb_writeback_work *work) | |
1da177e4 | 589 | { |
d46db3d5 WF |
590 | struct writeback_control wbc = { |
591 | .sync_mode = work->sync_mode, | |
592 | .tagged_writepages = work->tagged_writepages, | |
593 | .for_kupdate = work->for_kupdate, | |
594 | .for_background = work->for_background, | |
7747bd4b | 595 | .for_sync = work->for_sync, |
d46db3d5 WF |
596 | .range_cyclic = work->range_cyclic, |
597 | .range_start = 0, | |
598 | .range_end = LLONG_MAX, | |
599 | }; | |
600 | unsigned long start_time = jiffies; | |
601 | long write_chunk; | |
602 | long wrote = 0; /* count both pages and inodes */ | |
603 | ||
03ba3782 | 604 | while (!list_empty(&wb->b_io)) { |
7ccf19a8 | 605 | struct inode *inode = wb_inode(wb->b_io.prev); |
edadfb10 CH |
606 | |
607 | if (inode->i_sb != sb) { | |
d46db3d5 | 608 | if (work->sb) { |
edadfb10 CH |
609 | /* |
610 | * We only want to write back data for this | |
611 | * superblock, move all inodes not belonging | |
612 | * to it back onto the dirty list. | |
613 | */ | |
f758eeab | 614 | redirty_tail(inode, wb); |
edadfb10 CH |
615 | continue; |
616 | } | |
617 | ||
618 | /* | |
619 | * The inode belongs to a different superblock. | |
620 | * Bounce back to the caller to unpin this and | |
621 | * pin the next superblock. | |
622 | */ | |
d46db3d5 | 623 | break; |
edadfb10 CH |
624 | } |
625 | ||
9843b76a | 626 | /* |
331cbdee WL |
627 | * Don't bother with new inodes or inodes being freed, first |
628 | * kind does not need periodic writeout yet, and for the latter | |
9843b76a CH |
629 | * kind writeout is handled by the freer. |
630 | */ | |
250df6ed | 631 | spin_lock(&inode->i_lock); |
9843b76a | 632 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
250df6ed | 633 | spin_unlock(&inode->i_lock); |
fcc5c222 | 634 | redirty_tail(inode, wb); |
7ef0d737 NP |
635 | continue; |
636 | } | |
cc1676d9 JK |
637 | if ((inode->i_state & I_SYNC) && wbc.sync_mode != WB_SYNC_ALL) { |
638 | /* | |
639 | * If this inode is locked for writeback and we are not | |
640 | * doing writeback-for-data-integrity, move it to | |
641 | * b_more_io so that writeback can proceed with the | |
642 | * other inodes on s_io. | |
643 | * | |
644 | * We'll have another go at writing back this inode | |
645 | * when we completed a full scan of b_io. | |
646 | */ | |
647 | spin_unlock(&inode->i_lock); | |
648 | requeue_io(inode, wb); | |
649 | trace_writeback_sb_inodes_requeue(inode); | |
650 | continue; | |
651 | } | |
f0d07b7f JK |
652 | spin_unlock(&wb->list_lock); |
653 | ||
4f8ad655 JK |
654 | /* |
655 | * We already requeued the inode if it had I_SYNC set and we | |
656 | * are doing WB_SYNC_NONE writeback. So this catches only the | |
657 | * WB_SYNC_ALL case. | |
658 | */ | |
169ebd90 JK |
659 | if (inode->i_state & I_SYNC) { |
660 | /* Wait for I_SYNC. This function drops i_lock... */ | |
661 | inode_sleep_on_writeback(inode); | |
662 | /* Inode may be gone, start again */ | |
ead188f9 | 663 | spin_lock(&wb->list_lock); |
169ebd90 JK |
664 | continue; |
665 | } | |
4f8ad655 JK |
666 | inode->i_state |= I_SYNC; |
667 | spin_unlock(&inode->i_lock); | |
169ebd90 | 668 | |
1a12d8bd | 669 | write_chunk = writeback_chunk_size(wb->bdi, work); |
d46db3d5 WF |
670 | wbc.nr_to_write = write_chunk; |
671 | wbc.pages_skipped = 0; | |
250df6ed | 672 | |
169ebd90 JK |
673 | /* |
674 | * We use I_SYNC to pin the inode in memory. While it is set | |
675 | * evict_inode() will wait so the inode cannot be freed. | |
676 | */ | |
cd8ed2a4 | 677 | __writeback_single_inode(inode, &wbc); |
250df6ed | 678 | |
d46db3d5 WF |
679 | work->nr_pages -= write_chunk - wbc.nr_to_write; |
680 | wrote += write_chunk - wbc.nr_to_write; | |
4f8ad655 JK |
681 | spin_lock(&wb->list_lock); |
682 | spin_lock(&inode->i_lock); | |
d46db3d5 WF |
683 | if (!(inode->i_state & I_DIRTY)) |
684 | wrote++; | |
4f8ad655 JK |
685 | requeue_inode(inode, wb, &wbc); |
686 | inode_sync_complete(inode); | |
0f1b1fd8 | 687 | spin_unlock(&inode->i_lock); |
169ebd90 | 688 | cond_resched_lock(&wb->list_lock); |
d46db3d5 WF |
689 | /* |
690 | * bail out to wb_writeback() often enough to check | |
691 | * background threshold and other termination conditions. | |
692 | */ | |
693 | if (wrote) { | |
694 | if (time_is_before_jiffies(start_time + HZ / 10UL)) | |
695 | break; | |
696 | if (work->nr_pages <= 0) | |
697 | break; | |
8bc3be27 | 698 | } |
1da177e4 | 699 | } |
d46db3d5 | 700 | return wrote; |
f11c9c5c ES |
701 | } |
702 | ||
d46db3d5 WF |
703 | static long __writeback_inodes_wb(struct bdi_writeback *wb, |
704 | struct wb_writeback_work *work) | |
f11c9c5c | 705 | { |
d46db3d5 WF |
706 | unsigned long start_time = jiffies; |
707 | long wrote = 0; | |
38f21977 | 708 | |
f11c9c5c | 709 | while (!list_empty(&wb->b_io)) { |
7ccf19a8 | 710 | struct inode *inode = wb_inode(wb->b_io.prev); |
f11c9c5c | 711 | struct super_block *sb = inode->i_sb; |
9ecc2738 | 712 | |
12ad3ab6 | 713 | if (!grab_super_passive(sb)) { |
0e995816 WF |
714 | /* |
715 | * grab_super_passive() may fail consistently due to | |
716 | * s_umount being grabbed by someone else. Don't use | |
717 | * requeue_io() to avoid busy retrying the inode/sb. | |
718 | */ | |
719 | redirty_tail(inode, wb); | |
edadfb10 | 720 | continue; |
f11c9c5c | 721 | } |
d46db3d5 | 722 | wrote += writeback_sb_inodes(sb, wb, work); |
edadfb10 | 723 | drop_super(sb); |
f11c9c5c | 724 | |
d46db3d5 WF |
725 | /* refer to the same tests at the end of writeback_sb_inodes */ |
726 | if (wrote) { | |
727 | if (time_is_before_jiffies(start_time + HZ / 10UL)) | |
728 | break; | |
729 | if (work->nr_pages <= 0) | |
730 | break; | |
731 | } | |
f11c9c5c | 732 | } |
66f3b8e2 | 733 | /* Leave any unwritten inodes on b_io */ |
d46db3d5 | 734 | return wrote; |
66f3b8e2 JA |
735 | } |
736 | ||
7d9f073b | 737 | static long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages, |
0e175a18 | 738 | enum wb_reason reason) |
edadfb10 | 739 | { |
d46db3d5 WF |
740 | struct wb_writeback_work work = { |
741 | .nr_pages = nr_pages, | |
742 | .sync_mode = WB_SYNC_NONE, | |
743 | .range_cyclic = 1, | |
0e175a18 | 744 | .reason = reason, |
c4a391b5 JK |
745 | .older_than_this = jiffies, |
746 | .older_than_this_is_set = 1, | |
d46db3d5 | 747 | }; |
edadfb10 | 748 | |
f758eeab | 749 | spin_lock(&wb->list_lock); |
424b351f | 750 | if (list_empty(&wb->b_io)) |
ad4e38dd | 751 | queue_io(wb, &work); |
d46db3d5 | 752 | __writeback_inodes_wb(wb, &work); |
f758eeab | 753 | spin_unlock(&wb->list_lock); |
edadfb10 | 754 | |
d46db3d5 WF |
755 | return nr_pages - work.nr_pages; |
756 | } | |
03ba3782 | 757 | |
b00949aa | 758 | static bool over_bground_thresh(struct backing_dev_info *bdi) |
03ba3782 JA |
759 | { |
760 | unsigned long background_thresh, dirty_thresh; | |
761 | ||
16c4042f | 762 | global_dirty_limits(&background_thresh, &dirty_thresh); |
03ba3782 | 763 | |
b00949aa WF |
764 | if (global_page_state(NR_FILE_DIRTY) + |
765 | global_page_state(NR_UNSTABLE_NFS) > background_thresh) | |
766 | return true; | |
767 | ||
768 | if (bdi_stat(bdi, BDI_RECLAIMABLE) > | |
769 | bdi_dirty_limit(bdi, background_thresh)) | |
770 | return true; | |
771 | ||
772 | return false; | |
03ba3782 JA |
773 | } |
774 | ||
e98be2d5 WF |
775 | /* |
776 | * Called under wb->list_lock. If there are multiple wb per bdi, | |
777 | * only the flusher working on the first wb should do it. | |
778 | */ | |
779 | static void wb_update_bandwidth(struct bdi_writeback *wb, | |
780 | unsigned long start_time) | |
781 | { | |
af6a3113 | 782 | __bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, 0, start_time); |
e98be2d5 WF |
783 | } |
784 | ||
03ba3782 JA |
785 | /* |
786 | * Explicit flushing or periodic writeback of "old" data. | |
66f3b8e2 | 787 | * |
03ba3782 JA |
788 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
789 | * dirtying-time in the inode's address_space. So this periodic writeback code | |
790 | * just walks the superblock inode list, writing back any inodes which are | |
791 | * older than a specific point in time. | |
66f3b8e2 | 792 | * |
03ba3782 JA |
793 | * Try to run once per dirty_writeback_interval. But if a writeback event |
794 | * takes longer than a dirty_writeback_interval interval, then leave a | |
795 | * one-second gap. | |
66f3b8e2 | 796 | * |
03ba3782 JA |
797 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
798 | * all dirty pages if they are all attached to "old" mappings. | |
66f3b8e2 | 799 | */ |
c4a77a6c | 800 | static long wb_writeback(struct bdi_writeback *wb, |
83ba7b07 | 801 | struct wb_writeback_work *work) |
66f3b8e2 | 802 | { |
e98be2d5 | 803 | unsigned long wb_start = jiffies; |
d46db3d5 | 804 | long nr_pages = work->nr_pages; |
a5989bdc | 805 | struct inode *inode; |
d46db3d5 | 806 | long progress; |
66f3b8e2 | 807 | |
c4a391b5 JK |
808 | if (!work->older_than_this_is_set) { |
809 | work->older_than_this = jiffies; | |
810 | work->older_than_this_is_set = 1; | |
811 | } | |
38f21977 | 812 | |
e8dfc305 | 813 | spin_lock(&wb->list_lock); |
03ba3782 JA |
814 | for (;;) { |
815 | /* | |
d3ddec76 | 816 | * Stop writeback when nr_pages has been consumed |
03ba3782 | 817 | */ |
83ba7b07 | 818 | if (work->nr_pages <= 0) |
03ba3782 | 819 | break; |
66f3b8e2 | 820 | |
aa373cf5 JK |
821 | /* |
822 | * Background writeout and kupdate-style writeback may | |
823 | * run forever. Stop them if there is other work to do | |
824 | * so that e.g. sync can proceed. They'll be restarted | |
825 | * after the other works are all done. | |
826 | */ | |
827 | if ((work->for_background || work->for_kupdate) && | |
828 | !list_empty(&wb->bdi->work_list)) | |
829 | break; | |
830 | ||
38f21977 | 831 | /* |
d3ddec76 WF |
832 | * For background writeout, stop when we are below the |
833 | * background dirty threshold | |
38f21977 | 834 | */ |
b00949aa | 835 | if (work->for_background && !over_bground_thresh(wb->bdi)) |
03ba3782 | 836 | break; |
38f21977 | 837 | |
1bc36b64 JK |
838 | /* |
839 | * Kupdate and background works are special and we want to | |
840 | * include all inodes that need writing. Livelock avoidance is | |
841 | * handled by these works yielding to any other work so we are | |
842 | * safe. | |
843 | */ | |
ba9aa839 | 844 | if (work->for_kupdate) { |
c4a391b5 | 845 | work->older_than_this = jiffies - |
ba9aa839 | 846 | msecs_to_jiffies(dirty_expire_interval * 10); |
1bc36b64 | 847 | } else if (work->for_background) |
c4a391b5 | 848 | work->older_than_this = jiffies; |
028c2dd1 | 849 | |
d46db3d5 | 850 | trace_writeback_start(wb->bdi, work); |
e8dfc305 | 851 | if (list_empty(&wb->b_io)) |
ad4e38dd | 852 | queue_io(wb, work); |
83ba7b07 | 853 | if (work->sb) |
d46db3d5 | 854 | progress = writeback_sb_inodes(work->sb, wb, work); |
edadfb10 | 855 | else |
d46db3d5 WF |
856 | progress = __writeback_inodes_wb(wb, work); |
857 | trace_writeback_written(wb->bdi, work); | |
028c2dd1 | 858 | |
e98be2d5 | 859 | wb_update_bandwidth(wb, wb_start); |
03ba3782 JA |
860 | |
861 | /* | |
e6fb6da2 WF |
862 | * Did we write something? Try for more |
863 | * | |
864 | * Dirty inodes are moved to b_io for writeback in batches. | |
865 | * The completion of the current batch does not necessarily | |
866 | * mean the overall work is done. So we keep looping as long | |
867 | * as made some progress on cleaning pages or inodes. | |
03ba3782 | 868 | */ |
d46db3d5 | 869 | if (progress) |
71fd05a8 JA |
870 | continue; |
871 | /* | |
e6fb6da2 | 872 | * No more inodes for IO, bail |
71fd05a8 | 873 | */ |
b7a2441f | 874 | if (list_empty(&wb->b_more_io)) |
03ba3782 | 875 | break; |
71fd05a8 JA |
876 | /* |
877 | * Nothing written. Wait for some inode to | |
878 | * become available for writeback. Otherwise | |
879 | * we'll just busyloop. | |
880 | */ | |
71fd05a8 | 881 | if (!list_empty(&wb->b_more_io)) { |
d46db3d5 | 882 | trace_writeback_wait(wb->bdi, work); |
7ccf19a8 | 883 | inode = wb_inode(wb->b_more_io.prev); |
250df6ed | 884 | spin_lock(&inode->i_lock); |
f0d07b7f | 885 | spin_unlock(&wb->list_lock); |
169ebd90 JK |
886 | /* This function drops i_lock... */ |
887 | inode_sleep_on_writeback(inode); | |
f0d07b7f | 888 | spin_lock(&wb->list_lock); |
03ba3782 JA |
889 | } |
890 | } | |
e8dfc305 | 891 | spin_unlock(&wb->list_lock); |
03ba3782 | 892 | |
d46db3d5 | 893 | return nr_pages - work->nr_pages; |
03ba3782 JA |
894 | } |
895 | ||
896 | /* | |
83ba7b07 | 897 | * Return the next wb_writeback_work struct that hasn't been processed yet. |
03ba3782 | 898 | */ |
83ba7b07 | 899 | static struct wb_writeback_work * |
08852b6d | 900 | get_next_work_item(struct backing_dev_info *bdi) |
03ba3782 | 901 | { |
83ba7b07 | 902 | struct wb_writeback_work *work = NULL; |
03ba3782 | 903 | |
6467716a | 904 | spin_lock_bh(&bdi->wb_lock); |
83ba7b07 CH |
905 | if (!list_empty(&bdi->work_list)) { |
906 | work = list_entry(bdi->work_list.next, | |
907 | struct wb_writeback_work, list); | |
908 | list_del_init(&work->list); | |
03ba3782 | 909 | } |
6467716a | 910 | spin_unlock_bh(&bdi->wb_lock); |
83ba7b07 | 911 | return work; |
03ba3782 JA |
912 | } |
913 | ||
cdf01dd5 LT |
914 | /* |
915 | * Add in the number of potentially dirty inodes, because each inode | |
916 | * write can dirty pagecache in the underlying blockdev. | |
917 | */ | |
918 | static unsigned long get_nr_dirty_pages(void) | |
919 | { | |
920 | return global_page_state(NR_FILE_DIRTY) + | |
921 | global_page_state(NR_UNSTABLE_NFS) + | |
922 | get_nr_dirty_inodes(); | |
923 | } | |
924 | ||
6585027a JK |
925 | static long wb_check_background_flush(struct bdi_writeback *wb) |
926 | { | |
b00949aa | 927 | if (over_bground_thresh(wb->bdi)) { |
6585027a JK |
928 | |
929 | struct wb_writeback_work work = { | |
930 | .nr_pages = LONG_MAX, | |
931 | .sync_mode = WB_SYNC_NONE, | |
932 | .for_background = 1, | |
933 | .range_cyclic = 1, | |
0e175a18 | 934 | .reason = WB_REASON_BACKGROUND, |
6585027a JK |
935 | }; |
936 | ||
937 | return wb_writeback(wb, &work); | |
938 | } | |
939 | ||
940 | return 0; | |
941 | } | |
942 | ||
03ba3782 JA |
943 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
944 | { | |
945 | unsigned long expired; | |
946 | long nr_pages; | |
947 | ||
69b62d01 JA |
948 | /* |
949 | * When set to zero, disable periodic writeback | |
950 | */ | |
951 | if (!dirty_writeback_interval) | |
952 | return 0; | |
953 | ||
03ba3782 JA |
954 | expired = wb->last_old_flush + |
955 | msecs_to_jiffies(dirty_writeback_interval * 10); | |
956 | if (time_before(jiffies, expired)) | |
957 | return 0; | |
958 | ||
959 | wb->last_old_flush = jiffies; | |
cdf01dd5 | 960 | nr_pages = get_nr_dirty_pages(); |
03ba3782 | 961 | |
c4a77a6c | 962 | if (nr_pages) { |
83ba7b07 | 963 | struct wb_writeback_work work = { |
c4a77a6c JA |
964 | .nr_pages = nr_pages, |
965 | .sync_mode = WB_SYNC_NONE, | |
966 | .for_kupdate = 1, | |
967 | .range_cyclic = 1, | |
0e175a18 | 968 | .reason = WB_REASON_PERIODIC, |
c4a77a6c JA |
969 | }; |
970 | ||
83ba7b07 | 971 | return wb_writeback(wb, &work); |
c4a77a6c | 972 | } |
03ba3782 JA |
973 | |
974 | return 0; | |
975 | } | |
976 | ||
977 | /* | |
978 | * Retrieve work items and do the writeback they describe | |
979 | */ | |
25d130ba | 980 | static long wb_do_writeback(struct bdi_writeback *wb) |
03ba3782 JA |
981 | { |
982 | struct backing_dev_info *bdi = wb->bdi; | |
83ba7b07 | 983 | struct wb_writeback_work *work; |
c4a77a6c | 984 | long wrote = 0; |
03ba3782 | 985 | |
81d73a32 | 986 | set_bit(BDI_writeback_running, &wb->bdi->state); |
08852b6d | 987 | while ((work = get_next_work_item(bdi)) != NULL) { |
03ba3782 | 988 | |
455b2864 DC |
989 | trace_writeback_exec(bdi, work); |
990 | ||
83ba7b07 | 991 | wrote += wb_writeback(wb, work); |
03ba3782 JA |
992 | |
993 | /* | |
83ba7b07 CH |
994 | * Notify the caller of completion if this is a synchronous |
995 | * work item, otherwise just free it. | |
03ba3782 | 996 | */ |
83ba7b07 CH |
997 | if (work->done) |
998 | complete(work->done); | |
999 | else | |
1000 | kfree(work); | |
03ba3782 JA |
1001 | } |
1002 | ||
1003 | /* | |
1004 | * Check for periodic writeback, kupdated() style | |
1005 | */ | |
1006 | wrote += wb_check_old_data_flush(wb); | |
6585027a | 1007 | wrote += wb_check_background_flush(wb); |
81d73a32 | 1008 | clear_bit(BDI_writeback_running, &wb->bdi->state); |
03ba3782 JA |
1009 | |
1010 | return wrote; | |
1011 | } | |
1012 | ||
1013 | /* | |
1014 | * Handle writeback of dirty data for the device backed by this bdi. Also | |
839a8e86 | 1015 | * reschedules periodically and does kupdated style flushing. |
03ba3782 | 1016 | */ |
839a8e86 | 1017 | void bdi_writeback_workfn(struct work_struct *work) |
03ba3782 | 1018 | { |
839a8e86 TH |
1019 | struct bdi_writeback *wb = container_of(to_delayed_work(work), |
1020 | struct bdi_writeback, dwork); | |
08243900 | 1021 | struct backing_dev_info *bdi = wb->bdi; |
03ba3782 JA |
1022 | long pages_written; |
1023 | ||
ef3b1019 | 1024 | set_worker_desc("flush-%s", dev_name(bdi->dev)); |
766f9164 | 1025 | current->flags |= PF_SWAPWRITE; |
455b2864 | 1026 | |
839a8e86 TH |
1027 | if (likely(!current_is_workqueue_rescuer() || |
1028 | list_empty(&bdi->bdi_list))) { | |
6467716a | 1029 | /* |
839a8e86 TH |
1030 | * The normal path. Keep writing back @bdi until its |
1031 | * work_list is empty. Note that this path is also taken | |
1032 | * if @bdi is shutting down even when we're running off the | |
1033 | * rescuer as work_list needs to be drained. | |
6467716a | 1034 | */ |
839a8e86 | 1035 | do { |
25d130ba | 1036 | pages_written = wb_do_writeback(wb); |
839a8e86 TH |
1037 | trace_writeback_pages_written(pages_written); |
1038 | } while (!list_empty(&bdi->work_list)); | |
1039 | } else { | |
1040 | /* | |
1041 | * bdi_wq can't get enough workers and we're running off | |
1042 | * the emergency worker. Don't hog it. Hopefully, 1024 is | |
1043 | * enough for efficient IO. | |
1044 | */ | |
1045 | pages_written = writeback_inodes_wb(&bdi->wb, 1024, | |
1046 | WB_REASON_FORKER_THREAD); | |
455b2864 | 1047 | trace_writeback_pages_written(pages_written); |
03ba3782 JA |
1048 | } |
1049 | ||
839a8e86 TH |
1050 | if (!list_empty(&bdi->work_list) || |
1051 | (wb_has_dirty_io(wb) && dirty_writeback_interval)) | |
1052 | queue_delayed_work(bdi_wq, &wb->dwork, | |
1053 | msecs_to_jiffies(dirty_writeback_interval * 10)); | |
455b2864 | 1054 | |
839a8e86 | 1055 | current->flags &= ~PF_SWAPWRITE; |
03ba3782 JA |
1056 | } |
1057 | ||
1058 | /* | |
b8c2f347 CH |
1059 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
1060 | * the whole world. | |
03ba3782 | 1061 | */ |
0e175a18 | 1062 | void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) |
03ba3782 | 1063 | { |
b8c2f347 | 1064 | struct backing_dev_info *bdi; |
03ba3782 | 1065 | |
47df3dde JK |
1066 | if (!nr_pages) |
1067 | nr_pages = get_nr_dirty_pages(); | |
03ba3782 | 1068 | |
b8c2f347 | 1069 | rcu_read_lock(); |
cfc4ba53 | 1070 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
03ba3782 JA |
1071 | if (!bdi_has_dirty_io(bdi)) |
1072 | continue; | |
0e175a18 | 1073 | __bdi_start_writeback(bdi, nr_pages, false, reason); |
03ba3782 | 1074 | } |
cfc4ba53 | 1075 | rcu_read_unlock(); |
1da177e4 LT |
1076 | } |
1077 | ||
03ba3782 JA |
1078 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
1079 | { | |
1080 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { | |
1081 | struct dentry *dentry; | |
1082 | const char *name = "?"; | |
1083 | ||
1084 | dentry = d_find_alias(inode); | |
1085 | if (dentry) { | |
1086 | spin_lock(&dentry->d_lock); | |
1087 | name = (const char *) dentry->d_name.name; | |
1088 | } | |
1089 | printk(KERN_DEBUG | |
1090 | "%s(%d): dirtied inode %lu (%s) on %s\n", | |
1091 | current->comm, task_pid_nr(current), inode->i_ino, | |
1092 | name, inode->i_sb->s_id); | |
1093 | if (dentry) { | |
1094 | spin_unlock(&dentry->d_lock); | |
1095 | dput(dentry); | |
1096 | } | |
1097 | } | |
1098 | } | |
1099 | ||
1100 | /** | |
1101 | * __mark_inode_dirty - internal function | |
1102 | * @inode: inode to mark | |
1103 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) | |
1104 | * Mark an inode as dirty. Callers should use mark_inode_dirty or | |
1105 | * mark_inode_dirty_sync. | |
1da177e4 | 1106 | * |
03ba3782 JA |
1107 | * Put the inode on the super block's dirty list. |
1108 | * | |
1109 | * CAREFUL! We mark it dirty unconditionally, but move it onto the | |
1110 | * dirty list only if it is hashed or if it refers to a blockdev. | |
1111 | * If it was not hashed, it will never be added to the dirty list | |
1112 | * even if it is later hashed, as it will have been marked dirty already. | |
1113 | * | |
1114 | * In short, make sure you hash any inodes _before_ you start marking | |
1115 | * them dirty. | |
1da177e4 | 1116 | * |
03ba3782 JA |
1117 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
1118 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of | |
1119 | * the kernel-internal blockdev inode represents the dirtying time of the | |
1120 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use | |
1121 | * page->mapping->host, so the page-dirtying time is recorded in the internal | |
1122 | * blockdev inode. | |
1da177e4 | 1123 | */ |
03ba3782 | 1124 | void __mark_inode_dirty(struct inode *inode, int flags) |
1da177e4 | 1125 | { |
03ba3782 | 1126 | struct super_block *sb = inode->i_sb; |
253c34e9 | 1127 | struct backing_dev_info *bdi = NULL; |
1da177e4 | 1128 | |
03ba3782 JA |
1129 | /* |
1130 | * Don't do this for I_DIRTY_PAGES - that doesn't actually | |
1131 | * dirty the inode itself | |
1132 | */ | |
1133 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
9fb0a7da TH |
1134 | trace_writeback_dirty_inode_start(inode, flags); |
1135 | ||
03ba3782 | 1136 | if (sb->s_op->dirty_inode) |
aa385729 | 1137 | sb->s_op->dirty_inode(inode, flags); |
9fb0a7da TH |
1138 | |
1139 | trace_writeback_dirty_inode(inode, flags); | |
03ba3782 JA |
1140 | } |
1141 | ||
1142 | /* | |
1143 | * make sure that changes are seen by all cpus before we test i_state | |
1144 | * -- mikulas | |
1145 | */ | |
1146 | smp_mb(); | |
1147 | ||
1148 | /* avoid the locking if we can */ | |
1149 | if ((inode->i_state & flags) == flags) | |
1150 | return; | |
1151 | ||
1152 | if (unlikely(block_dump)) | |
1153 | block_dump___mark_inode_dirty(inode); | |
1154 | ||
250df6ed | 1155 | spin_lock(&inode->i_lock); |
03ba3782 JA |
1156 | if ((inode->i_state & flags) != flags) { |
1157 | const int was_dirty = inode->i_state & I_DIRTY; | |
1158 | ||
1159 | inode->i_state |= flags; | |
1160 | ||
1161 | /* | |
1162 | * If the inode is being synced, just update its dirty state. | |
1163 | * The unlocker will place the inode on the appropriate | |
1164 | * superblock list, based upon its state. | |
1165 | */ | |
1166 | if (inode->i_state & I_SYNC) | |
250df6ed | 1167 | goto out_unlock_inode; |
03ba3782 JA |
1168 | |
1169 | /* | |
1170 | * Only add valid (hashed) inodes to the superblock's | |
1171 | * dirty list. Add blockdev inodes as well. | |
1172 | */ | |
1173 | if (!S_ISBLK(inode->i_mode)) { | |
1d3382cb | 1174 | if (inode_unhashed(inode)) |
250df6ed | 1175 | goto out_unlock_inode; |
03ba3782 | 1176 | } |
a4ffdde6 | 1177 | if (inode->i_state & I_FREEING) |
250df6ed | 1178 | goto out_unlock_inode; |
03ba3782 JA |
1179 | |
1180 | /* | |
1181 | * If the inode was already on b_dirty/b_io/b_more_io, don't | |
1182 | * reposition it (that would break b_dirty time-ordering). | |
1183 | */ | |
1184 | if (!was_dirty) { | |
a66979ab | 1185 | bool wakeup_bdi = false; |
253c34e9 AB |
1186 | bdi = inode_to_bdi(inode); |
1187 | ||
146d7009 JB |
1188 | spin_unlock(&inode->i_lock); |
1189 | spin_lock(&bdi->wb.list_lock); | |
253c34e9 AB |
1190 | if (bdi_cap_writeback_dirty(bdi)) { |
1191 | WARN(!test_bit(BDI_registered, &bdi->state), | |
1192 | "bdi-%s not registered\n", bdi->name); | |
1193 | ||
1194 | /* | |
1195 | * If this is the first dirty inode for this | |
1196 | * bdi, we have to wake-up the corresponding | |
1197 | * bdi thread to make sure background | |
1198 | * write-back happens later. | |
1199 | */ | |
1200 | if (!wb_has_dirty_io(&bdi->wb)) | |
1201 | wakeup_bdi = true; | |
500b067c | 1202 | } |
03ba3782 JA |
1203 | |
1204 | inode->dirtied_when = jiffies; | |
7ccf19a8 | 1205 | list_move(&inode->i_wb_list, &bdi->wb.b_dirty); |
f758eeab | 1206 | spin_unlock(&bdi->wb.list_lock); |
a66979ab DC |
1207 | |
1208 | if (wakeup_bdi) | |
1209 | bdi_wakeup_thread_delayed(bdi); | |
1210 | return; | |
1da177e4 | 1211 | } |
1da177e4 | 1212 | } |
250df6ed DC |
1213 | out_unlock_inode: |
1214 | spin_unlock(&inode->i_lock); | |
253c34e9 | 1215 | |
03ba3782 JA |
1216 | } |
1217 | EXPORT_SYMBOL(__mark_inode_dirty); | |
1218 | ||
b6e51316 | 1219 | static void wait_sb_inodes(struct super_block *sb) |
03ba3782 JA |
1220 | { |
1221 | struct inode *inode, *old_inode = NULL; | |
1222 | ||
1223 | /* | |
1224 | * We need to be protected against the filesystem going from | |
1225 | * r/o to r/w or vice versa. | |
1226 | */ | |
b6e51316 | 1227 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
03ba3782 | 1228 | |
55fa6091 | 1229 | spin_lock(&inode_sb_list_lock); |
03ba3782 JA |
1230 | |
1231 | /* | |
1232 | * Data integrity sync. Must wait for all pages under writeback, | |
1233 | * because there may have been pages dirtied before our sync | |
1234 | * call, but which had writeout started before we write it out. | |
1235 | * In which case, the inode may not be on the dirty list, but | |
1236 | * we still have to wait for that writeout. | |
1237 | */ | |
b6e51316 | 1238 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
250df6ed | 1239 | struct address_space *mapping = inode->i_mapping; |
03ba3782 | 1240 | |
250df6ed DC |
1241 | spin_lock(&inode->i_lock); |
1242 | if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) || | |
1243 | (mapping->nrpages == 0)) { | |
1244 | spin_unlock(&inode->i_lock); | |
03ba3782 | 1245 | continue; |
250df6ed | 1246 | } |
03ba3782 | 1247 | __iget(inode); |
250df6ed | 1248 | spin_unlock(&inode->i_lock); |
55fa6091 DC |
1249 | spin_unlock(&inode_sb_list_lock); |
1250 | ||
03ba3782 | 1251 | /* |
55fa6091 DC |
1252 | * We hold a reference to 'inode' so it couldn't have been |
1253 | * removed from s_inodes list while we dropped the | |
1254 | * inode_sb_list_lock. We cannot iput the inode now as we can | |
1255 | * be holding the last reference and we cannot iput it under | |
1256 | * inode_sb_list_lock. So we keep the reference and iput it | |
1257 | * later. | |
03ba3782 JA |
1258 | */ |
1259 | iput(old_inode); | |
1260 | old_inode = inode; | |
1261 | ||
1262 | filemap_fdatawait(mapping); | |
1263 | ||
1264 | cond_resched(); | |
1265 | ||
55fa6091 | 1266 | spin_lock(&inode_sb_list_lock); |
03ba3782 | 1267 | } |
55fa6091 | 1268 | spin_unlock(&inode_sb_list_lock); |
03ba3782 | 1269 | iput(old_inode); |
1da177e4 LT |
1270 | } |
1271 | ||
d8a8559c | 1272 | /** |
3259f8be | 1273 | * writeback_inodes_sb_nr - writeback dirty inodes from given super_block |
d8a8559c | 1274 | * @sb: the superblock |
3259f8be | 1275 | * @nr: the number of pages to write |
786228ab | 1276 | * @reason: reason why some writeback work initiated |
1da177e4 | 1277 | * |
d8a8559c JA |
1278 | * Start writeback on some inodes on this super_block. No guarantees are made |
1279 | * on how many (if any) will be written, and this function does not wait | |
3259f8be | 1280 | * for IO completion of submitted IO. |
1da177e4 | 1281 | */ |
0e175a18 CW |
1282 | void writeback_inodes_sb_nr(struct super_block *sb, |
1283 | unsigned long nr, | |
1284 | enum wb_reason reason) | |
1da177e4 | 1285 | { |
83ba7b07 CH |
1286 | DECLARE_COMPLETION_ONSTACK(done); |
1287 | struct wb_writeback_work work = { | |
6e6938b6 WF |
1288 | .sb = sb, |
1289 | .sync_mode = WB_SYNC_NONE, | |
1290 | .tagged_writepages = 1, | |
1291 | .done = &done, | |
1292 | .nr_pages = nr, | |
0e175a18 | 1293 | .reason = reason, |
3c4d7165 | 1294 | }; |
d8a8559c | 1295 | |
6eedc701 JK |
1296 | if (sb->s_bdi == &noop_backing_dev_info) |
1297 | return; | |
cf37e972 | 1298 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
83ba7b07 CH |
1299 | bdi_queue_work(sb->s_bdi, &work); |
1300 | wait_for_completion(&done); | |
e913fc82 | 1301 | } |
3259f8be CM |
1302 | EXPORT_SYMBOL(writeback_inodes_sb_nr); |
1303 | ||
1304 | /** | |
1305 | * writeback_inodes_sb - writeback dirty inodes from given super_block | |
1306 | * @sb: the superblock | |
786228ab | 1307 | * @reason: reason why some writeback work was initiated |
3259f8be CM |
1308 | * |
1309 | * Start writeback on some inodes on this super_block. No guarantees are made | |
1310 | * on how many (if any) will be written, and this function does not wait | |
1311 | * for IO completion of submitted IO. | |
1312 | */ | |
0e175a18 | 1313 | void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
3259f8be | 1314 | { |
0e175a18 | 1315 | return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
3259f8be | 1316 | } |
0e3c9a22 | 1317 | EXPORT_SYMBOL(writeback_inodes_sb); |
e913fc82 | 1318 | |
17bd55d0 | 1319 | /** |
10ee27a0 | 1320 | * try_to_writeback_inodes_sb_nr - try to start writeback if none underway |
17bd55d0 | 1321 | * @sb: the superblock |
10ee27a0 MX |
1322 | * @nr: the number of pages to write |
1323 | * @reason: the reason of writeback | |
17bd55d0 | 1324 | * |
10ee27a0 | 1325 | * Invoke writeback_inodes_sb_nr if no writeback is currently underway. |
17bd55d0 ES |
1326 | * Returns 1 if writeback was started, 0 if not. |
1327 | */ | |
10ee27a0 MX |
1328 | int try_to_writeback_inodes_sb_nr(struct super_block *sb, |
1329 | unsigned long nr, | |
1330 | enum wb_reason reason) | |
17bd55d0 | 1331 | { |
10ee27a0 | 1332 | if (writeback_in_progress(sb->s_bdi)) |
17bd55d0 | 1333 | return 1; |
10ee27a0 MX |
1334 | |
1335 | if (!down_read_trylock(&sb->s_umount)) | |
17bd55d0 | 1336 | return 0; |
10ee27a0 MX |
1337 | |
1338 | writeback_inodes_sb_nr(sb, nr, reason); | |
1339 | up_read(&sb->s_umount); | |
1340 | return 1; | |
17bd55d0 | 1341 | } |
10ee27a0 | 1342 | EXPORT_SYMBOL(try_to_writeback_inodes_sb_nr); |
17bd55d0 | 1343 | |
3259f8be | 1344 | /** |
10ee27a0 | 1345 | * try_to_writeback_inodes_sb - try to start writeback if none underway |
3259f8be | 1346 | * @sb: the superblock |
786228ab | 1347 | * @reason: reason why some writeback work was initiated |
3259f8be | 1348 | * |
10ee27a0 | 1349 | * Implement by try_to_writeback_inodes_sb_nr() |
3259f8be CM |
1350 | * Returns 1 if writeback was started, 0 if not. |
1351 | */ | |
10ee27a0 | 1352 | int try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
3259f8be | 1353 | { |
10ee27a0 | 1354 | return try_to_writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
3259f8be | 1355 | } |
10ee27a0 | 1356 | EXPORT_SYMBOL(try_to_writeback_inodes_sb); |
3259f8be | 1357 | |
d8a8559c JA |
1358 | /** |
1359 | * sync_inodes_sb - sync sb inode pages | |
c4a391b5 JK |
1360 | * @sb: the superblock |
1361 | * @older_than_this: timestamp | |
d8a8559c JA |
1362 | * |
1363 | * This function writes and waits on any dirty inode belonging to this | |
c4a391b5 | 1364 | * superblock that has been dirtied before given timestamp. |
d8a8559c | 1365 | */ |
c4a391b5 | 1366 | void sync_inodes_sb(struct super_block *sb, unsigned long older_than_this) |
d8a8559c | 1367 | { |
83ba7b07 CH |
1368 | DECLARE_COMPLETION_ONSTACK(done); |
1369 | struct wb_writeback_work work = { | |
3c4d7165 CH |
1370 | .sb = sb, |
1371 | .sync_mode = WB_SYNC_ALL, | |
1372 | .nr_pages = LONG_MAX, | |
c4a391b5 JK |
1373 | .older_than_this = older_than_this, |
1374 | .older_than_this_is_set = 1, | |
3c4d7165 | 1375 | .range_cyclic = 0, |
83ba7b07 | 1376 | .done = &done, |
0e175a18 | 1377 | .reason = WB_REASON_SYNC, |
7747bd4b | 1378 | .for_sync = 1, |
3c4d7165 CH |
1379 | }; |
1380 | ||
6eedc701 JK |
1381 | /* Nothing to do? */ |
1382 | if (sb->s_bdi == &noop_backing_dev_info) | |
1383 | return; | |
cf37e972 CH |
1384 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
1385 | ||
83ba7b07 CH |
1386 | bdi_queue_work(sb->s_bdi, &work); |
1387 | wait_for_completion(&done); | |
1388 | ||
b6e51316 | 1389 | wait_sb_inodes(sb); |
1da177e4 | 1390 | } |
d8a8559c | 1391 | EXPORT_SYMBOL(sync_inodes_sb); |
1da177e4 | 1392 | |
1da177e4 | 1393 | /** |
7f04c26d AA |
1394 | * write_inode_now - write an inode to disk |
1395 | * @inode: inode to write to disk | |
1396 | * @sync: whether the write should be synchronous or not | |
1397 | * | |
1398 | * This function commits an inode to disk immediately if it is dirty. This is | |
1399 | * primarily needed by knfsd. | |
1da177e4 | 1400 | * |
7f04c26d | 1401 | * The caller must either have a ref on the inode or must have set I_WILL_FREE. |
1da177e4 | 1402 | */ |
1da177e4 LT |
1403 | int write_inode_now(struct inode *inode, int sync) |
1404 | { | |
f758eeab | 1405 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
1da177e4 LT |
1406 | struct writeback_control wbc = { |
1407 | .nr_to_write = LONG_MAX, | |
18914b18 | 1408 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
111ebb6e OH |
1409 | .range_start = 0, |
1410 | .range_end = LLONG_MAX, | |
1da177e4 LT |
1411 | }; |
1412 | ||
1413 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) | |
49364ce2 | 1414 | wbc.nr_to_write = 0; |
1da177e4 LT |
1415 | |
1416 | might_sleep(); | |
4f8ad655 | 1417 | return writeback_single_inode(inode, wb, &wbc); |
1da177e4 LT |
1418 | } |
1419 | EXPORT_SYMBOL(write_inode_now); | |
1420 | ||
1421 | /** | |
1422 | * sync_inode - write an inode and its pages to disk. | |
1423 | * @inode: the inode to sync | |
1424 | * @wbc: controls the writeback mode | |
1425 | * | |
1426 | * sync_inode() will write an inode and its pages to disk. It will also | |
1427 | * correctly update the inode on its superblock's dirty inode lists and will | |
1428 | * update inode->i_state. | |
1429 | * | |
1430 | * The caller must have a ref on the inode. | |
1431 | */ | |
1432 | int sync_inode(struct inode *inode, struct writeback_control *wbc) | |
1433 | { | |
4f8ad655 | 1434 | return writeback_single_inode(inode, &inode_to_bdi(inode)->wb, wbc); |
1da177e4 LT |
1435 | } |
1436 | EXPORT_SYMBOL(sync_inode); | |
c3765016 CH |
1437 | |
1438 | /** | |
c691b9d9 | 1439 | * sync_inode_metadata - write an inode to disk |
c3765016 CH |
1440 | * @inode: the inode to sync |
1441 | * @wait: wait for I/O to complete. | |
1442 | * | |
c691b9d9 | 1443 | * Write an inode to disk and adjust its dirty state after completion. |
c3765016 CH |
1444 | * |
1445 | * Note: only writes the actual inode, no associated data or other metadata. | |
1446 | */ | |
1447 | int sync_inode_metadata(struct inode *inode, int wait) | |
1448 | { | |
1449 | struct writeback_control wbc = { | |
1450 | .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE, | |
1451 | .nr_to_write = 0, /* metadata-only */ | |
1452 | }; | |
1453 | ||
1454 | return sync_inode(inode, &wbc); | |
1455 | } | |
1456 | EXPORT_SYMBOL(sync_inode_metadata); |