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 JA |
24 | #include <linux/kthread.h> |
25 | #include <linux/freezer.h> | |
1da177e4 LT |
26 | #include <linux/writeback.h> |
27 | #include <linux/blkdev.h> | |
28 | #include <linux/backing-dev.h> | |
455b2864 | 29 | #include <linux/tracepoint.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; | |
d46db3d5 | 43 | unsigned long *older_than_this; |
c4a77a6c | 44 | enum writeback_sync_modes sync_mode; |
6e6938b6 | 45 | unsigned int tagged_writepages:1; |
52957fe1 HS |
46 | unsigned int for_kupdate:1; |
47 | unsigned int range_cyclic:1; | |
48 | unsigned int for_background:1; | |
0e175a18 | 49 | enum wb_reason reason; /* why was writeback initiated? */ |
c4a77a6c | 50 | |
8010c3b6 | 51 | struct list_head list; /* pending work list */ |
83ba7b07 | 52 | struct completion *done; /* set if the caller waits */ |
03ba3782 JA |
53 | }; |
54 | ||
455b2864 DC |
55 | /* |
56 | * We don't actually have pdflush, but this one is exported though /proc... | |
57 | */ | |
58 | int nr_pdflush_threads; | |
59 | ||
f11b00f3 AB |
60 | /** |
61 | * writeback_in_progress - determine whether there is writeback in progress | |
62 | * @bdi: the device's backing_dev_info structure. | |
63 | * | |
03ba3782 JA |
64 | * Determine whether there is writeback waiting to be handled against a |
65 | * backing device. | |
f11b00f3 AB |
66 | */ |
67 | int writeback_in_progress(struct backing_dev_info *bdi) | |
68 | { | |
81d73a32 | 69 | return test_bit(BDI_writeback_running, &bdi->state); |
f11b00f3 AB |
70 | } |
71 | ||
692ebd17 JK |
72 | static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) |
73 | { | |
74 | struct super_block *sb = inode->i_sb; | |
692ebd17 | 75 | |
aaead25b CH |
76 | if (strcmp(sb->s_type->name, "bdev") == 0) |
77 | return inode->i_mapping->backing_dev_info; | |
78 | ||
79 | return sb->s_bdi; | |
692ebd17 JK |
80 | } |
81 | ||
7ccf19a8 NP |
82 | static inline struct inode *wb_inode(struct list_head *head) |
83 | { | |
84 | return list_entry(head, struct inode, i_wb_list); | |
85 | } | |
86 | ||
15eb77a0 WF |
87 | /* |
88 | * Include the creation of the trace points after defining the | |
89 | * wb_writeback_work structure and inline functions so that the definition | |
90 | * remains local to this file. | |
91 | */ | |
92 | #define CREATE_TRACE_POINTS | |
93 | #include <trace/events/writeback.h> | |
94 | ||
6585027a JK |
95 | /* Wakeup flusher thread or forker thread to fork it. Requires bdi->wb_lock. */ |
96 | static void bdi_wakeup_flusher(struct backing_dev_info *bdi) | |
03ba3782 | 97 | { |
fff5b85a AB |
98 | if (bdi->wb.task) { |
99 | wake_up_process(bdi->wb.task); | |
100 | } else { | |
101 | /* | |
102 | * The bdi thread isn't there, wake up the forker thread which | |
103 | * will create and run it. | |
104 | */ | |
03ba3782 | 105 | wake_up_process(default_backing_dev_info.wb.task); |
1da177e4 | 106 | } |
6585027a JK |
107 | } |
108 | ||
109 | static void bdi_queue_work(struct backing_dev_info *bdi, | |
110 | struct wb_writeback_work *work) | |
111 | { | |
112 | trace_writeback_queue(bdi, work); | |
113 | ||
114 | spin_lock_bh(&bdi->wb_lock); | |
115 | list_add_tail(&work->list, &bdi->work_list); | |
116 | if (!bdi->wb.task) | |
117 | trace_writeback_nothread(bdi, work); | |
118 | bdi_wakeup_flusher(bdi); | |
6467716a | 119 | spin_unlock_bh(&bdi->wb_lock); |
1da177e4 LT |
120 | } |
121 | ||
83ba7b07 CH |
122 | static void |
123 | __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, | |
0e175a18 | 124 | bool range_cyclic, enum wb_reason reason) |
1da177e4 | 125 | { |
83ba7b07 | 126 | struct wb_writeback_work *work; |
03ba3782 | 127 | |
bcddc3f0 JA |
128 | /* |
129 | * This is WB_SYNC_NONE writeback, so if allocation fails just | |
130 | * wakeup the thread for old dirty data writeback | |
131 | */ | |
83ba7b07 CH |
132 | work = kzalloc(sizeof(*work), GFP_ATOMIC); |
133 | if (!work) { | |
455b2864 DC |
134 | if (bdi->wb.task) { |
135 | trace_writeback_nowork(bdi); | |
83ba7b07 | 136 | wake_up_process(bdi->wb.task); |
455b2864 | 137 | } |
83ba7b07 | 138 | return; |
bcddc3f0 | 139 | } |
03ba3782 | 140 | |
83ba7b07 CH |
141 | work->sync_mode = WB_SYNC_NONE; |
142 | work->nr_pages = nr_pages; | |
143 | work->range_cyclic = range_cyclic; | |
0e175a18 | 144 | work->reason = reason; |
03ba3782 | 145 | |
83ba7b07 | 146 | bdi_queue_work(bdi, work); |
b6e51316 JA |
147 | } |
148 | ||
149 | /** | |
150 | * bdi_start_writeback - start writeback | |
151 | * @bdi: the backing device to write from | |
152 | * @nr_pages: the number of pages to write | |
786228ab | 153 | * @reason: reason why some writeback work was initiated |
b6e51316 JA |
154 | * |
155 | * Description: | |
156 | * This does WB_SYNC_NONE opportunistic writeback. The IO is only | |
25985edc | 157 | * started when this function returns, we make no guarantees on |
0e3c9a22 | 158 | * completion. Caller need not hold sb s_umount semaphore. |
b6e51316 JA |
159 | * |
160 | */ | |
0e175a18 CW |
161 | void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, |
162 | enum wb_reason reason) | |
b6e51316 | 163 | { |
0e175a18 | 164 | __bdi_start_writeback(bdi, nr_pages, true, reason); |
c5444198 | 165 | } |
d3ddec76 | 166 | |
c5444198 CH |
167 | /** |
168 | * bdi_start_background_writeback - start background writeback | |
169 | * @bdi: the backing device to write from | |
170 | * | |
171 | * Description: | |
6585027a JK |
172 | * This makes sure WB_SYNC_NONE background writeback happens. When |
173 | * this function returns, it is only guaranteed that for given BDI | |
174 | * some IO is happening if we are over background dirty threshold. | |
175 | * Caller need not hold sb s_umount semaphore. | |
c5444198 CH |
176 | */ |
177 | void bdi_start_background_writeback(struct backing_dev_info *bdi) | |
178 | { | |
6585027a JK |
179 | /* |
180 | * We just wake up the flusher thread. It will perform background | |
181 | * writeback as soon as there is no other work to do. | |
182 | */ | |
71927e84 | 183 | trace_writeback_wake_background(bdi); |
6585027a JK |
184 | spin_lock_bh(&bdi->wb_lock); |
185 | bdi_wakeup_flusher(bdi); | |
186 | spin_unlock_bh(&bdi->wb_lock); | |
1da177e4 LT |
187 | } |
188 | ||
a66979ab DC |
189 | /* |
190 | * Remove the inode from the writeback list it is on. | |
191 | */ | |
192 | void inode_wb_list_del(struct inode *inode) | |
193 | { | |
f758eeab CH |
194 | struct backing_dev_info *bdi = inode_to_bdi(inode); |
195 | ||
196 | spin_lock(&bdi->wb.list_lock); | |
a66979ab | 197 | list_del_init(&inode->i_wb_list); |
f758eeab | 198 | spin_unlock(&bdi->wb.list_lock); |
a66979ab DC |
199 | } |
200 | ||
6610a0bc AM |
201 | /* |
202 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the | |
203 | * furthest end of its superblock's dirty-inode list. | |
204 | * | |
205 | * Before stamping the inode's ->dirtied_when, we check to see whether it is | |
66f3b8e2 | 206 | * already the most-recently-dirtied inode on the b_dirty list. If that is |
6610a0bc AM |
207 | * the case then the inode must have been redirtied while it was being written |
208 | * out and we don't reset its dirtied_when. | |
209 | */ | |
f758eeab | 210 | static void redirty_tail(struct inode *inode, struct bdi_writeback *wb) |
6610a0bc | 211 | { |
f758eeab | 212 | assert_spin_locked(&wb->list_lock); |
03ba3782 | 213 | if (!list_empty(&wb->b_dirty)) { |
66f3b8e2 | 214 | struct inode *tail; |
6610a0bc | 215 | |
7ccf19a8 | 216 | tail = wb_inode(wb->b_dirty.next); |
66f3b8e2 | 217 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
6610a0bc AM |
218 | inode->dirtied_when = jiffies; |
219 | } | |
7ccf19a8 | 220 | list_move(&inode->i_wb_list, &wb->b_dirty); |
6610a0bc AM |
221 | } |
222 | ||
c986d1e2 | 223 | /* |
66f3b8e2 | 224 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
c986d1e2 | 225 | */ |
f758eeab | 226 | static void requeue_io(struct inode *inode, struct bdi_writeback *wb) |
c986d1e2 | 227 | { |
f758eeab | 228 | assert_spin_locked(&wb->list_lock); |
7ccf19a8 | 229 | list_move(&inode->i_wb_list, &wb->b_more_io); |
c986d1e2 AM |
230 | } |
231 | ||
1c0eeaf5 JE |
232 | static void inode_sync_complete(struct inode *inode) |
233 | { | |
365b94ae JK |
234 | inode->i_state &= ~I_SYNC; |
235 | /* Waiters must see I_SYNC cleared before being woken up */ | |
1c0eeaf5 JE |
236 | smp_mb(); |
237 | wake_up_bit(&inode->i_state, __I_SYNC); | |
238 | } | |
239 | ||
d2caa3c5 JL |
240 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
241 | { | |
242 | bool ret = time_after(inode->dirtied_when, t); | |
243 | #ifndef CONFIG_64BIT | |
244 | /* | |
245 | * For inodes being constantly redirtied, dirtied_when can get stuck. | |
246 | * It _appears_ to be in the future, but is actually in distant past. | |
247 | * This test is necessary to prevent such wrapped-around relative times | |
5b0830cb | 248 | * from permanently stopping the whole bdi writeback. |
d2caa3c5 JL |
249 | */ |
250 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); | |
251 | #endif | |
252 | return ret; | |
253 | } | |
254 | ||
2c136579 | 255 | /* |
697e6fed JK |
256 | * Move expired (dirtied after work->older_than_this) dirty inodes from |
257 | * @delaying_queue to @dispatch_queue. | |
2c136579 | 258 | */ |
e84d0a4f | 259 | static int move_expired_inodes(struct list_head *delaying_queue, |
2c136579 | 260 | struct list_head *dispatch_queue, |
ad4e38dd | 261 | struct wb_writeback_work *work) |
2c136579 | 262 | { |
5c03449d SL |
263 | LIST_HEAD(tmp); |
264 | struct list_head *pos, *node; | |
cf137307 | 265 | struct super_block *sb = NULL; |
5c03449d | 266 | struct inode *inode; |
cf137307 | 267 | int do_sb_sort = 0; |
e84d0a4f | 268 | int moved = 0; |
5c03449d | 269 | |
2c136579 | 270 | while (!list_empty(delaying_queue)) { |
7ccf19a8 | 271 | inode = wb_inode(delaying_queue->prev); |
ad4e38dd CW |
272 | if (work->older_than_this && |
273 | inode_dirtied_after(inode, *work->older_than_this)) | |
2c136579 | 274 | break; |
cf137307 JA |
275 | if (sb && sb != inode->i_sb) |
276 | do_sb_sort = 1; | |
277 | sb = inode->i_sb; | |
7ccf19a8 | 278 | list_move(&inode->i_wb_list, &tmp); |
e84d0a4f | 279 | moved++; |
5c03449d SL |
280 | } |
281 | ||
cf137307 JA |
282 | /* just one sb in list, splice to dispatch_queue and we're done */ |
283 | if (!do_sb_sort) { | |
284 | list_splice(&tmp, dispatch_queue); | |
e84d0a4f | 285 | goto out; |
cf137307 JA |
286 | } |
287 | ||
5c03449d SL |
288 | /* Move inodes from one superblock together */ |
289 | while (!list_empty(&tmp)) { | |
7ccf19a8 | 290 | sb = wb_inode(tmp.prev)->i_sb; |
5c03449d | 291 | list_for_each_prev_safe(pos, node, &tmp) { |
7ccf19a8 | 292 | inode = wb_inode(pos); |
5c03449d | 293 | if (inode->i_sb == sb) |
7ccf19a8 | 294 | list_move(&inode->i_wb_list, dispatch_queue); |
5c03449d | 295 | } |
2c136579 | 296 | } |
e84d0a4f WF |
297 | out: |
298 | return moved; | |
2c136579 FW |
299 | } |
300 | ||
301 | /* | |
302 | * Queue all expired dirty inodes for io, eldest first. | |
4ea879b9 WF |
303 | * Before |
304 | * newly dirtied b_dirty b_io b_more_io | |
305 | * =============> gf edc BA | |
306 | * After | |
307 | * newly dirtied b_dirty b_io b_more_io | |
308 | * =============> g fBAedc | |
309 | * | | |
310 | * +--> dequeue for IO | |
2c136579 | 311 | */ |
ad4e38dd | 312 | static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work) |
66f3b8e2 | 313 | { |
e84d0a4f | 314 | int moved; |
f758eeab | 315 | assert_spin_locked(&wb->list_lock); |
4ea879b9 | 316 | list_splice_init(&wb->b_more_io, &wb->b_io); |
ad4e38dd CW |
317 | moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, work); |
318 | trace_writeback_queue_io(wb, work, moved); | |
66f3b8e2 JA |
319 | } |
320 | ||
a9185b41 | 321 | static int write_inode(struct inode *inode, struct writeback_control *wbc) |
08d8e974 | 322 | { |
03ba3782 | 323 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) |
a9185b41 | 324 | return inode->i_sb->s_op->write_inode(inode, wbc); |
03ba3782 | 325 | return 0; |
08d8e974 | 326 | } |
08d8e974 | 327 | |
1da177e4 | 328 | /* |
169ebd90 JK |
329 | * Wait for writeback on an inode to complete. Called with i_lock held. |
330 | * Caller must make sure inode cannot go away when we drop i_lock. | |
01c03194 | 331 | */ |
169ebd90 JK |
332 | static void __inode_wait_for_writeback(struct inode *inode) |
333 | __releases(inode->i_lock) | |
334 | __acquires(inode->i_lock) | |
01c03194 CH |
335 | { |
336 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); | |
337 | wait_queue_head_t *wqh; | |
338 | ||
339 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
250df6ed DC |
340 | while (inode->i_state & I_SYNC) { |
341 | spin_unlock(&inode->i_lock); | |
01c03194 | 342 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
250df6ed | 343 | spin_lock(&inode->i_lock); |
58a9d3d8 | 344 | } |
01c03194 CH |
345 | } |
346 | ||
169ebd90 JK |
347 | /* |
348 | * Wait for writeback on an inode to complete. Caller must have inode pinned. | |
349 | */ | |
350 | void inode_wait_for_writeback(struct inode *inode) | |
351 | { | |
352 | spin_lock(&inode->i_lock); | |
353 | __inode_wait_for_writeback(inode); | |
354 | spin_unlock(&inode->i_lock); | |
355 | } | |
356 | ||
357 | /* | |
358 | * Sleep until I_SYNC is cleared. This function must be called with i_lock | |
359 | * held and drops it. It is aimed for callers not holding any inode reference | |
360 | * so once i_lock is dropped, inode can go away. | |
361 | */ | |
362 | static void inode_sleep_on_writeback(struct inode *inode) | |
363 | __releases(inode->i_lock) | |
364 | { | |
365 | DEFINE_WAIT(wait); | |
366 | wait_queue_head_t *wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
367 | int sleep; | |
368 | ||
369 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
370 | sleep = inode->i_state & I_SYNC; | |
371 | spin_unlock(&inode->i_lock); | |
372 | if (sleep) | |
373 | schedule(); | |
374 | finish_wait(wqh, &wait); | |
375 | } | |
376 | ||
ccb26b5a JK |
377 | /* |
378 | * Find proper writeback list for the inode depending on its current state and | |
379 | * possibly also change of its state while we were doing writeback. Here we | |
380 | * handle things such as livelock prevention or fairness of writeback among | |
381 | * inodes. This function can be called only by flusher thread - noone else | |
382 | * processes all inodes in writeback lists and requeueing inodes behind flusher | |
383 | * thread's back can have unexpected consequences. | |
384 | */ | |
385 | static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, | |
386 | struct writeback_control *wbc) | |
387 | { | |
388 | if (inode->i_state & I_FREEING) | |
389 | return; | |
390 | ||
391 | /* | |
392 | * Sync livelock prevention. Each inode is tagged and synced in one | |
393 | * shot. If still dirty, it will be redirty_tail()'ed below. Update | |
394 | * the dirty time to prevent enqueue and sync it again. | |
395 | */ | |
396 | if ((inode->i_state & I_DIRTY) && | |
397 | (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)) | |
398 | inode->dirtied_when = jiffies; | |
399 | ||
4f8ad655 JK |
400 | if (wbc->pages_skipped) { |
401 | /* | |
402 | * writeback is not making progress due to locked | |
403 | * buffers. Skip this inode for now. | |
404 | */ | |
405 | redirty_tail(inode, wb); | |
406 | return; | |
407 | } | |
408 | ||
ccb26b5a JK |
409 | if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) { |
410 | /* | |
411 | * We didn't write back all the pages. nfs_writepages() | |
412 | * sometimes bales out without doing anything. | |
413 | */ | |
414 | if (wbc->nr_to_write <= 0) { | |
415 | /* Slice used up. Queue for next turn. */ | |
416 | requeue_io(inode, wb); | |
417 | } else { | |
418 | /* | |
419 | * Writeback blocked by something other than | |
420 | * congestion. Delay the inode for some time to | |
421 | * avoid spinning on the CPU (100% iowait) | |
422 | * retrying writeback of the dirty page/inode | |
423 | * that cannot be performed immediately. | |
424 | */ | |
425 | redirty_tail(inode, wb); | |
426 | } | |
427 | } else if (inode->i_state & I_DIRTY) { | |
428 | /* | |
429 | * Filesystems can dirty the inode during writeback operations, | |
430 | * such as delayed allocation during submission or metadata | |
431 | * updates after data IO completion. | |
432 | */ | |
433 | redirty_tail(inode, wb); | |
434 | } else { | |
435 | /* The inode is clean. Remove from writeback lists. */ | |
436 | list_del_init(&inode->i_wb_list); | |
437 | } | |
438 | } | |
439 | ||
01c03194 | 440 | /* |
4f8ad655 JK |
441 | * Write out an inode and its dirty pages. Do not update the writeback list |
442 | * linkage. That is left to the caller. The caller is also responsible for | |
443 | * setting I_SYNC flag and calling inode_sync_complete() to clear it. | |
1da177e4 LT |
444 | */ |
445 | static int | |
4f8ad655 JK |
446 | __writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, |
447 | struct writeback_control *wbc) | |
1da177e4 | 448 | { |
1da177e4 | 449 | struct address_space *mapping = inode->i_mapping; |
251d6a47 | 450 | long nr_to_write = wbc->nr_to_write; |
01c03194 | 451 | unsigned dirty; |
1da177e4 LT |
452 | int ret; |
453 | ||
4f8ad655 | 454 | WARN_ON(!(inode->i_state & I_SYNC)); |
1da177e4 LT |
455 | |
456 | ret = do_writepages(mapping, wbc); | |
457 | ||
26821ed4 CH |
458 | /* |
459 | * Make sure to wait on the data before writing out the metadata. | |
460 | * This is important for filesystems that modify metadata on data | |
461 | * I/O completion. | |
462 | */ | |
a9185b41 | 463 | if (wbc->sync_mode == WB_SYNC_ALL) { |
26821ed4 | 464 | int err = filemap_fdatawait(mapping); |
1da177e4 LT |
465 | if (ret == 0) |
466 | ret = err; | |
467 | } | |
468 | ||
5547e8aa DM |
469 | /* |
470 | * Some filesystems may redirty the inode during the writeback | |
471 | * due to delalloc, clear dirty metadata flags right before | |
472 | * write_inode() | |
473 | */ | |
250df6ed | 474 | spin_lock(&inode->i_lock); |
6290be1c JK |
475 | /* Clear I_DIRTY_PAGES if we've written out all dirty pages */ |
476 | if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) | |
477 | inode->i_state &= ~I_DIRTY_PAGES; | |
5547e8aa DM |
478 | dirty = inode->i_state & I_DIRTY; |
479 | inode->i_state &= ~(I_DIRTY_SYNC | I_DIRTY_DATASYNC); | |
250df6ed | 480 | spin_unlock(&inode->i_lock); |
26821ed4 CH |
481 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
482 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
a9185b41 | 483 | int err = write_inode(inode, wbc); |
1da177e4 LT |
484 | if (ret == 0) |
485 | ret = err; | |
486 | } | |
4f8ad655 JK |
487 | trace_writeback_single_inode(inode, wbc, nr_to_write); |
488 | return ret; | |
489 | } | |
490 | ||
491 | /* | |
492 | * Write out an inode's dirty pages. Either the caller has an active reference | |
493 | * on the inode or the inode has I_WILL_FREE set. | |
494 | * | |
495 | * This function is designed to be called for writing back one inode which | |
496 | * we go e.g. from filesystem. Flusher thread uses __writeback_single_inode() | |
497 | * and does more profound writeback list handling in writeback_sb_inodes(). | |
498 | */ | |
499 | static int | |
500 | writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, | |
501 | struct writeback_control *wbc) | |
502 | { | |
503 | int ret = 0; | |
504 | ||
505 | spin_lock(&inode->i_lock); | |
506 | if (!atomic_read(&inode->i_count)) | |
507 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); | |
508 | else | |
509 | WARN_ON(inode->i_state & I_WILL_FREE); | |
510 | ||
511 | if (inode->i_state & I_SYNC) { | |
512 | if (wbc->sync_mode != WB_SYNC_ALL) | |
513 | goto out; | |
514 | /* | |
169ebd90 JK |
515 | * It's a data-integrity sync. We must wait. Since callers hold |
516 | * inode reference or inode has I_WILL_FREE set, it cannot go | |
517 | * away under us. | |
4f8ad655 | 518 | */ |
169ebd90 | 519 | __inode_wait_for_writeback(inode); |
4f8ad655 JK |
520 | } |
521 | WARN_ON(inode->i_state & I_SYNC); | |
522 | /* | |
523 | * Skip inode if it is clean. We don't want to mess with writeback | |
524 | * lists in this function since flusher thread may be doing for example | |
525 | * sync in parallel and if we move the inode, it could get skipped. So | |
526 | * here we make sure inode is on some writeback list and leave it there | |
527 | * unless we have completely cleaned the inode. | |
528 | */ | |
529 | if (!(inode->i_state & I_DIRTY)) | |
530 | goto out; | |
531 | inode->i_state |= I_SYNC; | |
532 | spin_unlock(&inode->i_lock); | |
533 | ||
534 | ret = __writeback_single_inode(inode, wb, wbc); | |
1da177e4 | 535 | |
f758eeab | 536 | spin_lock(&wb->list_lock); |
250df6ed | 537 | spin_lock(&inode->i_lock); |
4f8ad655 JK |
538 | /* |
539 | * If inode is clean, remove it from writeback lists. Otherwise don't | |
540 | * touch it. See comment above for explanation. | |
541 | */ | |
542 | if (!(inode->i_state & I_DIRTY)) | |
543 | list_del_init(&inode->i_wb_list); | |
544 | spin_unlock(&wb->list_lock); | |
1c0eeaf5 | 545 | inode_sync_complete(inode); |
4f8ad655 JK |
546 | out: |
547 | spin_unlock(&inode->i_lock); | |
1da177e4 LT |
548 | return ret; |
549 | } | |
550 | ||
1a12d8bd WF |
551 | static long writeback_chunk_size(struct backing_dev_info *bdi, |
552 | struct wb_writeback_work *work) | |
d46db3d5 WF |
553 | { |
554 | long pages; | |
555 | ||
556 | /* | |
557 | * WB_SYNC_ALL mode does livelock avoidance by syncing dirty | |
558 | * inodes/pages in one big loop. Setting wbc.nr_to_write=LONG_MAX | |
559 | * here avoids calling into writeback_inodes_wb() more than once. | |
560 | * | |
561 | * The intended call sequence for WB_SYNC_ALL writeback is: | |
562 | * | |
563 | * wb_writeback() | |
564 | * writeback_sb_inodes() <== called only once | |
565 | * write_cache_pages() <== called once for each inode | |
566 | * (quickly) tag currently dirty pages | |
567 | * (maybe slowly) sync all tagged pages | |
568 | */ | |
569 | if (work->sync_mode == WB_SYNC_ALL || work->tagged_writepages) | |
570 | pages = LONG_MAX; | |
1a12d8bd WF |
571 | else { |
572 | pages = min(bdi->avg_write_bandwidth / 2, | |
573 | global_dirty_limit / DIRTY_SCOPE); | |
574 | pages = min(pages, work->nr_pages); | |
575 | pages = round_down(pages + MIN_WRITEBACK_PAGES, | |
576 | MIN_WRITEBACK_PAGES); | |
577 | } | |
d46db3d5 WF |
578 | |
579 | return pages; | |
580 | } | |
581 | ||
f11c9c5c ES |
582 | /* |
583 | * Write a portion of b_io inodes which belong to @sb. | |
edadfb10 CH |
584 | * |
585 | * If @only_this_sb is true, then find and write all such | |
f11c9c5c ES |
586 | * inodes. Otherwise write only ones which go sequentially |
587 | * in reverse order. | |
edadfb10 | 588 | * |
d46db3d5 | 589 | * Return the number of pages and/or inodes written. |
f11c9c5c | 590 | */ |
d46db3d5 WF |
591 | static long writeback_sb_inodes(struct super_block *sb, |
592 | struct bdi_writeback *wb, | |
593 | struct wb_writeback_work *work) | |
1da177e4 | 594 | { |
d46db3d5 WF |
595 | struct writeback_control wbc = { |
596 | .sync_mode = work->sync_mode, | |
597 | .tagged_writepages = work->tagged_writepages, | |
598 | .for_kupdate = work->for_kupdate, | |
599 | .for_background = work->for_background, | |
600 | .range_cyclic = work->range_cyclic, | |
601 | .range_start = 0, | |
602 | .range_end = LLONG_MAX, | |
603 | }; | |
604 | unsigned long start_time = jiffies; | |
605 | long write_chunk; | |
606 | long wrote = 0; /* count both pages and inodes */ | |
607 | ||
03ba3782 | 608 | while (!list_empty(&wb->b_io)) { |
7ccf19a8 | 609 | struct inode *inode = wb_inode(wb->b_io.prev); |
edadfb10 CH |
610 | |
611 | if (inode->i_sb != sb) { | |
d46db3d5 | 612 | if (work->sb) { |
edadfb10 CH |
613 | /* |
614 | * We only want to write back data for this | |
615 | * superblock, move all inodes not belonging | |
616 | * to it back onto the dirty list. | |
617 | */ | |
f758eeab | 618 | redirty_tail(inode, wb); |
edadfb10 CH |
619 | continue; |
620 | } | |
621 | ||
622 | /* | |
623 | * The inode belongs to a different superblock. | |
624 | * Bounce back to the caller to unpin this and | |
625 | * pin the next superblock. | |
626 | */ | |
d46db3d5 | 627 | break; |
edadfb10 CH |
628 | } |
629 | ||
9843b76a CH |
630 | /* |
631 | * Don't bother with new inodes or inodes beeing freed, first | |
632 | * kind does not need peridic writeout yet, and for the latter | |
633 | * kind writeout is handled by the freer. | |
634 | */ | |
250df6ed | 635 | spin_lock(&inode->i_lock); |
9843b76a | 636 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
250df6ed | 637 | spin_unlock(&inode->i_lock); |
fcc5c222 | 638 | redirty_tail(inode, wb); |
7ef0d737 NP |
639 | continue; |
640 | } | |
cc1676d9 JK |
641 | if ((inode->i_state & I_SYNC) && wbc.sync_mode != WB_SYNC_ALL) { |
642 | /* | |
643 | * If this inode is locked for writeback and we are not | |
644 | * doing writeback-for-data-integrity, move it to | |
645 | * b_more_io so that writeback can proceed with the | |
646 | * other inodes on s_io. | |
647 | * | |
648 | * We'll have another go at writing back this inode | |
649 | * when we completed a full scan of b_io. | |
650 | */ | |
651 | spin_unlock(&inode->i_lock); | |
652 | requeue_io(inode, wb); | |
653 | trace_writeback_sb_inodes_requeue(inode); | |
654 | continue; | |
655 | } | |
f0d07b7f JK |
656 | spin_unlock(&wb->list_lock); |
657 | ||
4f8ad655 JK |
658 | /* |
659 | * We already requeued the inode if it had I_SYNC set and we | |
660 | * are doing WB_SYNC_NONE writeback. So this catches only the | |
661 | * WB_SYNC_ALL case. | |
662 | */ | |
169ebd90 JK |
663 | if (inode->i_state & I_SYNC) { |
664 | /* Wait for I_SYNC. This function drops i_lock... */ | |
665 | inode_sleep_on_writeback(inode); | |
666 | /* Inode may be gone, start again */ | |
ead188f9 | 667 | spin_lock(&wb->list_lock); |
169ebd90 JK |
668 | continue; |
669 | } | |
4f8ad655 JK |
670 | inode->i_state |= I_SYNC; |
671 | spin_unlock(&inode->i_lock); | |
169ebd90 | 672 | |
1a12d8bd | 673 | write_chunk = writeback_chunk_size(wb->bdi, work); |
d46db3d5 WF |
674 | wbc.nr_to_write = write_chunk; |
675 | wbc.pages_skipped = 0; | |
250df6ed | 676 | |
169ebd90 JK |
677 | /* |
678 | * We use I_SYNC to pin the inode in memory. While it is set | |
679 | * evict_inode() will wait so the inode cannot be freed. | |
680 | */ | |
4f8ad655 | 681 | __writeback_single_inode(inode, wb, &wbc); |
250df6ed | 682 | |
d46db3d5 WF |
683 | work->nr_pages -= write_chunk - wbc.nr_to_write; |
684 | wrote += write_chunk - wbc.nr_to_write; | |
4f8ad655 JK |
685 | spin_lock(&wb->list_lock); |
686 | spin_lock(&inode->i_lock); | |
d46db3d5 WF |
687 | if (!(inode->i_state & I_DIRTY)) |
688 | wrote++; | |
4f8ad655 JK |
689 | requeue_inode(inode, wb, &wbc); |
690 | inode_sync_complete(inode); | |
0f1b1fd8 | 691 | spin_unlock(&inode->i_lock); |
169ebd90 | 692 | cond_resched_lock(&wb->list_lock); |
d46db3d5 WF |
693 | /* |
694 | * bail out to wb_writeback() often enough to check | |
695 | * background threshold and other termination conditions. | |
696 | */ | |
697 | if (wrote) { | |
698 | if (time_is_before_jiffies(start_time + HZ / 10UL)) | |
699 | break; | |
700 | if (work->nr_pages <= 0) | |
701 | break; | |
8bc3be27 | 702 | } |
1da177e4 | 703 | } |
d46db3d5 | 704 | return wrote; |
f11c9c5c ES |
705 | } |
706 | ||
d46db3d5 WF |
707 | static long __writeback_inodes_wb(struct bdi_writeback *wb, |
708 | struct wb_writeback_work *work) | |
f11c9c5c | 709 | { |
d46db3d5 WF |
710 | unsigned long start_time = jiffies; |
711 | long wrote = 0; | |
38f21977 | 712 | |
f11c9c5c | 713 | while (!list_empty(&wb->b_io)) { |
7ccf19a8 | 714 | struct inode *inode = wb_inode(wb->b_io.prev); |
f11c9c5c | 715 | struct super_block *sb = inode->i_sb; |
9ecc2738 | 716 | |
12ad3ab6 | 717 | if (!grab_super_passive(sb)) { |
0e995816 WF |
718 | /* |
719 | * grab_super_passive() may fail consistently due to | |
720 | * s_umount being grabbed by someone else. Don't use | |
721 | * requeue_io() to avoid busy retrying the inode/sb. | |
722 | */ | |
723 | redirty_tail(inode, wb); | |
edadfb10 | 724 | continue; |
f11c9c5c | 725 | } |
d46db3d5 | 726 | wrote += writeback_sb_inodes(sb, wb, work); |
edadfb10 | 727 | drop_super(sb); |
f11c9c5c | 728 | |
d46db3d5 WF |
729 | /* refer to the same tests at the end of writeback_sb_inodes */ |
730 | if (wrote) { | |
731 | if (time_is_before_jiffies(start_time + HZ / 10UL)) | |
732 | break; | |
733 | if (work->nr_pages <= 0) | |
734 | break; | |
735 | } | |
f11c9c5c | 736 | } |
66f3b8e2 | 737 | /* Leave any unwritten inodes on b_io */ |
d46db3d5 | 738 | return wrote; |
66f3b8e2 JA |
739 | } |
740 | ||
0e175a18 CW |
741 | long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages, |
742 | enum wb_reason reason) | |
edadfb10 | 743 | { |
d46db3d5 WF |
744 | struct wb_writeback_work work = { |
745 | .nr_pages = nr_pages, | |
746 | .sync_mode = WB_SYNC_NONE, | |
747 | .range_cyclic = 1, | |
0e175a18 | 748 | .reason = reason, |
d46db3d5 | 749 | }; |
edadfb10 | 750 | |
f758eeab | 751 | spin_lock(&wb->list_lock); |
424b351f | 752 | if (list_empty(&wb->b_io)) |
ad4e38dd | 753 | queue_io(wb, &work); |
d46db3d5 | 754 | __writeback_inodes_wb(wb, &work); |
f758eeab | 755 | spin_unlock(&wb->list_lock); |
edadfb10 | 756 | |
d46db3d5 WF |
757 | return nr_pages - work.nr_pages; |
758 | } | |
03ba3782 | 759 | |
b00949aa | 760 | static bool over_bground_thresh(struct backing_dev_info *bdi) |
03ba3782 JA |
761 | { |
762 | unsigned long background_thresh, dirty_thresh; | |
763 | ||
16c4042f | 764 | global_dirty_limits(&background_thresh, &dirty_thresh); |
03ba3782 | 765 | |
b00949aa WF |
766 | if (global_page_state(NR_FILE_DIRTY) + |
767 | global_page_state(NR_UNSTABLE_NFS) > background_thresh) | |
768 | return true; | |
769 | ||
770 | if (bdi_stat(bdi, BDI_RECLAIMABLE) > | |
771 | bdi_dirty_limit(bdi, background_thresh)) | |
772 | return true; | |
773 | ||
774 | return false; | |
03ba3782 JA |
775 | } |
776 | ||
e98be2d5 WF |
777 | /* |
778 | * Called under wb->list_lock. If there are multiple wb per bdi, | |
779 | * only the flusher working on the first wb should do it. | |
780 | */ | |
781 | static void wb_update_bandwidth(struct bdi_writeback *wb, | |
782 | unsigned long start_time) | |
783 | { | |
af6a3113 | 784 | __bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, 0, start_time); |
e98be2d5 WF |
785 | } |
786 | ||
03ba3782 JA |
787 | /* |
788 | * Explicit flushing or periodic writeback of "old" data. | |
66f3b8e2 | 789 | * |
03ba3782 JA |
790 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
791 | * dirtying-time in the inode's address_space. So this periodic writeback code | |
792 | * just walks the superblock inode list, writing back any inodes which are | |
793 | * older than a specific point in time. | |
66f3b8e2 | 794 | * |
03ba3782 JA |
795 | * Try to run once per dirty_writeback_interval. But if a writeback event |
796 | * takes longer than a dirty_writeback_interval interval, then leave a | |
797 | * one-second gap. | |
66f3b8e2 | 798 | * |
03ba3782 JA |
799 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
800 | * all dirty pages if they are all attached to "old" mappings. | |
66f3b8e2 | 801 | */ |
c4a77a6c | 802 | static long wb_writeback(struct bdi_writeback *wb, |
83ba7b07 | 803 | struct wb_writeback_work *work) |
66f3b8e2 | 804 | { |
e98be2d5 | 805 | unsigned long wb_start = jiffies; |
d46db3d5 | 806 | long nr_pages = work->nr_pages; |
03ba3782 | 807 | unsigned long oldest_jif; |
a5989bdc | 808 | struct inode *inode; |
d46db3d5 | 809 | long progress; |
66f3b8e2 | 810 | |
e185dda8 | 811 | oldest_jif = jiffies; |
d46db3d5 | 812 | work->older_than_this = &oldest_jif; |
38f21977 | 813 | |
e8dfc305 | 814 | spin_lock(&wb->list_lock); |
03ba3782 JA |
815 | for (;;) { |
816 | /* | |
d3ddec76 | 817 | * Stop writeback when nr_pages has been consumed |
03ba3782 | 818 | */ |
83ba7b07 | 819 | if (work->nr_pages <= 0) |
03ba3782 | 820 | break; |
66f3b8e2 | 821 | |
aa373cf5 JK |
822 | /* |
823 | * Background writeout and kupdate-style writeback may | |
824 | * run forever. Stop them if there is other work to do | |
825 | * so that e.g. sync can proceed. They'll be restarted | |
826 | * after the other works are all done. | |
827 | */ | |
828 | if ((work->for_background || work->for_kupdate) && | |
829 | !list_empty(&wb->bdi->work_list)) | |
830 | break; | |
831 | ||
38f21977 | 832 | /* |
d3ddec76 WF |
833 | * For background writeout, stop when we are below the |
834 | * background dirty threshold | |
38f21977 | 835 | */ |
b00949aa | 836 | if (work->for_background && !over_bground_thresh(wb->bdi)) |
03ba3782 | 837 | break; |
38f21977 | 838 | |
1bc36b64 JK |
839 | /* |
840 | * Kupdate and background works are special and we want to | |
841 | * include all inodes that need writing. Livelock avoidance is | |
842 | * handled by these works yielding to any other work so we are | |
843 | * safe. | |
844 | */ | |
ba9aa839 WF |
845 | if (work->for_kupdate) { |
846 | oldest_jif = jiffies - | |
847 | msecs_to_jiffies(dirty_expire_interval * 10); | |
1bc36b64 JK |
848 | } else if (work->for_background) |
849 | oldest_jif = jiffies; | |
028c2dd1 | 850 | |
d46db3d5 | 851 | trace_writeback_start(wb->bdi, work); |
e8dfc305 | 852 | if (list_empty(&wb->b_io)) |
ad4e38dd | 853 | queue_io(wb, work); |
83ba7b07 | 854 | if (work->sb) |
d46db3d5 | 855 | progress = writeback_sb_inodes(work->sb, wb, work); |
edadfb10 | 856 | else |
d46db3d5 WF |
857 | progress = __writeback_inodes_wb(wb, work); |
858 | trace_writeback_written(wb->bdi, work); | |
028c2dd1 | 859 | |
e98be2d5 | 860 | wb_update_bandwidth(wb, wb_start); |
03ba3782 JA |
861 | |
862 | /* | |
e6fb6da2 WF |
863 | * Did we write something? Try for more |
864 | * | |
865 | * Dirty inodes are moved to b_io for writeback in batches. | |
866 | * The completion of the current batch does not necessarily | |
867 | * mean the overall work is done. So we keep looping as long | |
868 | * as made some progress on cleaning pages or inodes. | |
03ba3782 | 869 | */ |
d46db3d5 | 870 | if (progress) |
71fd05a8 JA |
871 | continue; |
872 | /* | |
e6fb6da2 | 873 | * No more inodes for IO, bail |
71fd05a8 | 874 | */ |
b7a2441f | 875 | if (list_empty(&wb->b_more_io)) |
03ba3782 | 876 | break; |
71fd05a8 JA |
877 | /* |
878 | * Nothing written. Wait for some inode to | |
879 | * become available for writeback. Otherwise | |
880 | * we'll just busyloop. | |
881 | */ | |
71fd05a8 | 882 | if (!list_empty(&wb->b_more_io)) { |
d46db3d5 | 883 | trace_writeback_wait(wb->bdi, work); |
7ccf19a8 | 884 | inode = wb_inode(wb->b_more_io.prev); |
250df6ed | 885 | spin_lock(&inode->i_lock); |
f0d07b7f | 886 | spin_unlock(&wb->list_lock); |
169ebd90 JK |
887 | /* This function drops i_lock... */ |
888 | inode_sleep_on_writeback(inode); | |
f0d07b7f | 889 | spin_lock(&wb->list_lock); |
03ba3782 JA |
890 | } |
891 | } | |
e8dfc305 | 892 | spin_unlock(&wb->list_lock); |
03ba3782 | 893 | |
d46db3d5 | 894 | return nr_pages - work->nr_pages; |
03ba3782 JA |
895 | } |
896 | ||
897 | /* | |
83ba7b07 | 898 | * Return the next wb_writeback_work struct that hasn't been processed yet. |
03ba3782 | 899 | */ |
83ba7b07 | 900 | static struct wb_writeback_work * |
08852b6d | 901 | get_next_work_item(struct backing_dev_info *bdi) |
03ba3782 | 902 | { |
83ba7b07 | 903 | struct wb_writeback_work *work = NULL; |
03ba3782 | 904 | |
6467716a | 905 | spin_lock_bh(&bdi->wb_lock); |
83ba7b07 CH |
906 | if (!list_empty(&bdi->work_list)) { |
907 | work = list_entry(bdi->work_list.next, | |
908 | struct wb_writeback_work, list); | |
909 | list_del_init(&work->list); | |
03ba3782 | 910 | } |
6467716a | 911 | spin_unlock_bh(&bdi->wb_lock); |
83ba7b07 | 912 | return work; |
03ba3782 JA |
913 | } |
914 | ||
cdf01dd5 LT |
915 | /* |
916 | * Add in the number of potentially dirty inodes, because each inode | |
917 | * write can dirty pagecache in the underlying blockdev. | |
918 | */ | |
919 | static unsigned long get_nr_dirty_pages(void) | |
920 | { | |
921 | return global_page_state(NR_FILE_DIRTY) + | |
922 | global_page_state(NR_UNSTABLE_NFS) + | |
923 | get_nr_dirty_inodes(); | |
924 | } | |
925 | ||
6585027a JK |
926 | static long wb_check_background_flush(struct bdi_writeback *wb) |
927 | { | |
b00949aa | 928 | if (over_bground_thresh(wb->bdi)) { |
6585027a JK |
929 | |
930 | struct wb_writeback_work work = { | |
931 | .nr_pages = LONG_MAX, | |
932 | .sync_mode = WB_SYNC_NONE, | |
933 | .for_background = 1, | |
934 | .range_cyclic = 1, | |
0e175a18 | 935 | .reason = WB_REASON_BACKGROUND, |
6585027a JK |
936 | }; |
937 | ||
938 | return wb_writeback(wb, &work); | |
939 | } | |
940 | ||
941 | return 0; | |
942 | } | |
943 | ||
03ba3782 JA |
944 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
945 | { | |
946 | unsigned long expired; | |
947 | long nr_pages; | |
948 | ||
69b62d01 JA |
949 | /* |
950 | * When set to zero, disable periodic writeback | |
951 | */ | |
952 | if (!dirty_writeback_interval) | |
953 | return 0; | |
954 | ||
03ba3782 JA |
955 | expired = wb->last_old_flush + |
956 | msecs_to_jiffies(dirty_writeback_interval * 10); | |
957 | if (time_before(jiffies, expired)) | |
958 | return 0; | |
959 | ||
960 | wb->last_old_flush = jiffies; | |
cdf01dd5 | 961 | nr_pages = get_nr_dirty_pages(); |
03ba3782 | 962 | |
c4a77a6c | 963 | if (nr_pages) { |
83ba7b07 | 964 | struct wb_writeback_work work = { |
c4a77a6c JA |
965 | .nr_pages = nr_pages, |
966 | .sync_mode = WB_SYNC_NONE, | |
967 | .for_kupdate = 1, | |
968 | .range_cyclic = 1, | |
0e175a18 | 969 | .reason = WB_REASON_PERIODIC, |
c4a77a6c JA |
970 | }; |
971 | ||
83ba7b07 | 972 | return wb_writeback(wb, &work); |
c4a77a6c | 973 | } |
03ba3782 JA |
974 | |
975 | return 0; | |
976 | } | |
977 | ||
978 | /* | |
979 | * Retrieve work items and do the writeback they describe | |
980 | */ | |
981 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) | |
982 | { | |
983 | struct backing_dev_info *bdi = wb->bdi; | |
83ba7b07 | 984 | struct wb_writeback_work *work; |
c4a77a6c | 985 | long wrote = 0; |
03ba3782 | 986 | |
81d73a32 | 987 | set_bit(BDI_writeback_running, &wb->bdi->state); |
08852b6d | 988 | while ((work = get_next_work_item(bdi)) != NULL) { |
03ba3782 JA |
989 | /* |
990 | * Override sync mode, in case we must wait for completion | |
83ba7b07 | 991 | * because this thread is exiting now. |
03ba3782 JA |
992 | */ |
993 | if (force_wait) | |
83ba7b07 | 994 | work->sync_mode = WB_SYNC_ALL; |
03ba3782 | 995 | |
455b2864 DC |
996 | trace_writeback_exec(bdi, work); |
997 | ||
83ba7b07 | 998 | wrote += wb_writeback(wb, work); |
03ba3782 JA |
999 | |
1000 | /* | |
83ba7b07 CH |
1001 | * Notify the caller of completion if this is a synchronous |
1002 | * work item, otherwise just free it. | |
03ba3782 | 1003 | */ |
83ba7b07 CH |
1004 | if (work->done) |
1005 | complete(work->done); | |
1006 | else | |
1007 | kfree(work); | |
03ba3782 JA |
1008 | } |
1009 | ||
1010 | /* | |
1011 | * Check for periodic writeback, kupdated() style | |
1012 | */ | |
1013 | wrote += wb_check_old_data_flush(wb); | |
6585027a | 1014 | wrote += wb_check_background_flush(wb); |
81d73a32 | 1015 | clear_bit(BDI_writeback_running, &wb->bdi->state); |
03ba3782 JA |
1016 | |
1017 | return wrote; | |
1018 | } | |
1019 | ||
1020 | /* | |
1021 | * Handle writeback of dirty data for the device backed by this bdi. Also | |
1022 | * wakes up periodically and does kupdated style flushing. | |
1023 | */ | |
08243900 | 1024 | int bdi_writeback_thread(void *data) |
03ba3782 | 1025 | { |
08243900 CH |
1026 | struct bdi_writeback *wb = data; |
1027 | struct backing_dev_info *bdi = wb->bdi; | |
03ba3782 JA |
1028 | long pages_written; |
1029 | ||
766f9164 | 1030 | current->flags |= PF_SWAPWRITE; |
08243900 | 1031 | set_freezable(); |
ecd58403 | 1032 | wb->last_active = jiffies; |
08243900 CH |
1033 | |
1034 | /* | |
1035 | * Our parent may run at a different priority, just set us to normal | |
1036 | */ | |
1037 | set_user_nice(current, 0); | |
1038 | ||
455b2864 DC |
1039 | trace_writeback_thread_start(bdi); |
1040 | ||
8a32c441 | 1041 | while (!kthread_freezable_should_stop(NULL)) { |
6467716a AB |
1042 | /* |
1043 | * Remove own delayed wake-up timer, since we are already awake | |
1044 | * and we'll take care of the preriodic write-back. | |
1045 | */ | |
1046 | del_timer(&wb->wakeup_timer); | |
1047 | ||
03ba3782 JA |
1048 | pages_written = wb_do_writeback(wb, 0); |
1049 | ||
455b2864 DC |
1050 | trace_writeback_pages_written(pages_written); |
1051 | ||
03ba3782 | 1052 | if (pages_written) |
ecd58403 | 1053 | wb->last_active = jiffies; |
03ba3782 | 1054 | |
297252c8 | 1055 | set_current_state(TASK_INTERRUPTIBLE); |
b76b4014 | 1056 | if (!list_empty(&bdi->work_list) || kthread_should_stop()) { |
f9eadbbd | 1057 | __set_current_state(TASK_RUNNING); |
297252c8 | 1058 | continue; |
03ba3782 JA |
1059 | } |
1060 | ||
253c34e9 | 1061 | if (wb_has_dirty_io(wb) && dirty_writeback_interval) |
fff5b85a | 1062 | schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10)); |
253c34e9 AB |
1063 | else { |
1064 | /* | |
1065 | * We have nothing to do, so can go sleep without any | |
1066 | * timeout and save power. When a work is queued or | |
1067 | * something is made dirty - we will be woken up. | |
1068 | */ | |
297252c8 | 1069 | schedule(); |
f9eadbbd | 1070 | } |
03ba3782 JA |
1071 | } |
1072 | ||
fff5b85a | 1073 | /* Flush any work that raced with us exiting */ |
08243900 CH |
1074 | if (!list_empty(&bdi->work_list)) |
1075 | wb_do_writeback(wb, 1); | |
455b2864 DC |
1076 | |
1077 | trace_writeback_thread_stop(bdi); | |
03ba3782 JA |
1078 | return 0; |
1079 | } | |
1080 | ||
08243900 | 1081 | |
03ba3782 | 1082 | /* |
b8c2f347 CH |
1083 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
1084 | * the whole world. | |
03ba3782 | 1085 | */ |
0e175a18 | 1086 | void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) |
03ba3782 | 1087 | { |
b8c2f347 | 1088 | struct backing_dev_info *bdi; |
03ba3782 | 1089 | |
83ba7b07 CH |
1090 | if (!nr_pages) { |
1091 | nr_pages = global_page_state(NR_FILE_DIRTY) + | |
b8c2f347 CH |
1092 | global_page_state(NR_UNSTABLE_NFS); |
1093 | } | |
03ba3782 | 1094 | |
b8c2f347 | 1095 | rcu_read_lock(); |
cfc4ba53 | 1096 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
03ba3782 JA |
1097 | if (!bdi_has_dirty_io(bdi)) |
1098 | continue; | |
0e175a18 | 1099 | __bdi_start_writeback(bdi, nr_pages, false, reason); |
03ba3782 | 1100 | } |
cfc4ba53 | 1101 | rcu_read_unlock(); |
1da177e4 LT |
1102 | } |
1103 | ||
03ba3782 JA |
1104 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
1105 | { | |
1106 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { | |
1107 | struct dentry *dentry; | |
1108 | const char *name = "?"; | |
1109 | ||
1110 | dentry = d_find_alias(inode); | |
1111 | if (dentry) { | |
1112 | spin_lock(&dentry->d_lock); | |
1113 | name = (const char *) dentry->d_name.name; | |
1114 | } | |
1115 | printk(KERN_DEBUG | |
1116 | "%s(%d): dirtied inode %lu (%s) on %s\n", | |
1117 | current->comm, task_pid_nr(current), inode->i_ino, | |
1118 | name, inode->i_sb->s_id); | |
1119 | if (dentry) { | |
1120 | spin_unlock(&dentry->d_lock); | |
1121 | dput(dentry); | |
1122 | } | |
1123 | } | |
1124 | } | |
1125 | ||
1126 | /** | |
1127 | * __mark_inode_dirty - internal function | |
1128 | * @inode: inode to mark | |
1129 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) | |
1130 | * Mark an inode as dirty. Callers should use mark_inode_dirty or | |
1131 | * mark_inode_dirty_sync. | |
1da177e4 | 1132 | * |
03ba3782 JA |
1133 | * Put the inode on the super block's dirty list. |
1134 | * | |
1135 | * CAREFUL! We mark it dirty unconditionally, but move it onto the | |
1136 | * dirty list only if it is hashed or if it refers to a blockdev. | |
1137 | * If it was not hashed, it will never be added to the dirty list | |
1138 | * even if it is later hashed, as it will have been marked dirty already. | |
1139 | * | |
1140 | * In short, make sure you hash any inodes _before_ you start marking | |
1141 | * them dirty. | |
1da177e4 | 1142 | * |
03ba3782 JA |
1143 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
1144 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of | |
1145 | * the kernel-internal blockdev inode represents the dirtying time of the | |
1146 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use | |
1147 | * page->mapping->host, so the page-dirtying time is recorded in the internal | |
1148 | * blockdev inode. | |
1da177e4 | 1149 | */ |
03ba3782 | 1150 | void __mark_inode_dirty(struct inode *inode, int flags) |
1da177e4 | 1151 | { |
03ba3782 | 1152 | struct super_block *sb = inode->i_sb; |
253c34e9 | 1153 | struct backing_dev_info *bdi = NULL; |
1da177e4 | 1154 | |
03ba3782 JA |
1155 | /* |
1156 | * Don't do this for I_DIRTY_PAGES - that doesn't actually | |
1157 | * dirty the inode itself | |
1158 | */ | |
1159 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
1160 | if (sb->s_op->dirty_inode) | |
aa385729 | 1161 | sb->s_op->dirty_inode(inode, flags); |
03ba3782 JA |
1162 | } |
1163 | ||
1164 | /* | |
1165 | * make sure that changes are seen by all cpus before we test i_state | |
1166 | * -- mikulas | |
1167 | */ | |
1168 | smp_mb(); | |
1169 | ||
1170 | /* avoid the locking if we can */ | |
1171 | if ((inode->i_state & flags) == flags) | |
1172 | return; | |
1173 | ||
1174 | if (unlikely(block_dump)) | |
1175 | block_dump___mark_inode_dirty(inode); | |
1176 | ||
250df6ed | 1177 | spin_lock(&inode->i_lock); |
03ba3782 JA |
1178 | if ((inode->i_state & flags) != flags) { |
1179 | const int was_dirty = inode->i_state & I_DIRTY; | |
1180 | ||
1181 | inode->i_state |= flags; | |
1182 | ||
1183 | /* | |
1184 | * If the inode is being synced, just update its dirty state. | |
1185 | * The unlocker will place the inode on the appropriate | |
1186 | * superblock list, based upon its state. | |
1187 | */ | |
1188 | if (inode->i_state & I_SYNC) | |
250df6ed | 1189 | goto out_unlock_inode; |
03ba3782 JA |
1190 | |
1191 | /* | |
1192 | * Only add valid (hashed) inodes to the superblock's | |
1193 | * dirty list. Add blockdev inodes as well. | |
1194 | */ | |
1195 | if (!S_ISBLK(inode->i_mode)) { | |
1d3382cb | 1196 | if (inode_unhashed(inode)) |
250df6ed | 1197 | goto out_unlock_inode; |
03ba3782 | 1198 | } |
a4ffdde6 | 1199 | if (inode->i_state & I_FREEING) |
250df6ed | 1200 | goto out_unlock_inode; |
03ba3782 JA |
1201 | |
1202 | /* | |
1203 | * If the inode was already on b_dirty/b_io/b_more_io, don't | |
1204 | * reposition it (that would break b_dirty time-ordering). | |
1205 | */ | |
1206 | if (!was_dirty) { | |
a66979ab | 1207 | bool wakeup_bdi = false; |
253c34e9 AB |
1208 | bdi = inode_to_bdi(inode); |
1209 | ||
1210 | if (bdi_cap_writeback_dirty(bdi)) { | |
1211 | WARN(!test_bit(BDI_registered, &bdi->state), | |
1212 | "bdi-%s not registered\n", bdi->name); | |
1213 | ||
1214 | /* | |
1215 | * If this is the first dirty inode for this | |
1216 | * bdi, we have to wake-up the corresponding | |
1217 | * bdi thread to make sure background | |
1218 | * write-back happens later. | |
1219 | */ | |
1220 | if (!wb_has_dirty_io(&bdi->wb)) | |
1221 | wakeup_bdi = true; | |
500b067c | 1222 | } |
03ba3782 | 1223 | |
a66979ab | 1224 | spin_unlock(&inode->i_lock); |
f758eeab | 1225 | spin_lock(&bdi->wb.list_lock); |
03ba3782 | 1226 | inode->dirtied_when = jiffies; |
7ccf19a8 | 1227 | list_move(&inode->i_wb_list, &bdi->wb.b_dirty); |
f758eeab | 1228 | spin_unlock(&bdi->wb.list_lock); |
a66979ab DC |
1229 | |
1230 | if (wakeup_bdi) | |
1231 | bdi_wakeup_thread_delayed(bdi); | |
1232 | return; | |
1da177e4 | 1233 | } |
1da177e4 | 1234 | } |
250df6ed DC |
1235 | out_unlock_inode: |
1236 | spin_unlock(&inode->i_lock); | |
253c34e9 | 1237 | |
03ba3782 JA |
1238 | } |
1239 | EXPORT_SYMBOL(__mark_inode_dirty); | |
1240 | ||
b6e51316 | 1241 | static void wait_sb_inodes(struct super_block *sb) |
03ba3782 JA |
1242 | { |
1243 | struct inode *inode, *old_inode = NULL; | |
1244 | ||
1245 | /* | |
1246 | * We need to be protected against the filesystem going from | |
1247 | * r/o to r/w or vice versa. | |
1248 | */ | |
b6e51316 | 1249 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
03ba3782 | 1250 | |
55fa6091 | 1251 | spin_lock(&inode_sb_list_lock); |
03ba3782 JA |
1252 | |
1253 | /* | |
1254 | * Data integrity sync. Must wait for all pages under writeback, | |
1255 | * because there may have been pages dirtied before our sync | |
1256 | * call, but which had writeout started before we write it out. | |
1257 | * In which case, the inode may not be on the dirty list, but | |
1258 | * we still have to wait for that writeout. | |
1259 | */ | |
b6e51316 | 1260 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
250df6ed | 1261 | struct address_space *mapping = inode->i_mapping; |
03ba3782 | 1262 | |
250df6ed DC |
1263 | spin_lock(&inode->i_lock); |
1264 | if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) || | |
1265 | (mapping->nrpages == 0)) { | |
1266 | spin_unlock(&inode->i_lock); | |
03ba3782 | 1267 | continue; |
250df6ed | 1268 | } |
03ba3782 | 1269 | __iget(inode); |
250df6ed | 1270 | spin_unlock(&inode->i_lock); |
55fa6091 DC |
1271 | spin_unlock(&inode_sb_list_lock); |
1272 | ||
03ba3782 | 1273 | /* |
55fa6091 DC |
1274 | * We hold a reference to 'inode' so it couldn't have been |
1275 | * removed from s_inodes list while we dropped the | |
1276 | * inode_sb_list_lock. We cannot iput the inode now as we can | |
1277 | * be holding the last reference and we cannot iput it under | |
1278 | * inode_sb_list_lock. So we keep the reference and iput it | |
1279 | * later. | |
03ba3782 JA |
1280 | */ |
1281 | iput(old_inode); | |
1282 | old_inode = inode; | |
1283 | ||
1284 | filemap_fdatawait(mapping); | |
1285 | ||
1286 | cond_resched(); | |
1287 | ||
55fa6091 | 1288 | spin_lock(&inode_sb_list_lock); |
03ba3782 | 1289 | } |
55fa6091 | 1290 | spin_unlock(&inode_sb_list_lock); |
03ba3782 | 1291 | iput(old_inode); |
1da177e4 LT |
1292 | } |
1293 | ||
d8a8559c | 1294 | /** |
3259f8be | 1295 | * writeback_inodes_sb_nr - writeback dirty inodes from given super_block |
d8a8559c | 1296 | * @sb: the superblock |
3259f8be | 1297 | * @nr: the number of pages to write |
786228ab | 1298 | * @reason: reason why some writeback work initiated |
1da177e4 | 1299 | * |
d8a8559c JA |
1300 | * Start writeback on some inodes on this super_block. No guarantees are made |
1301 | * on how many (if any) will be written, and this function does not wait | |
3259f8be | 1302 | * for IO completion of submitted IO. |
1da177e4 | 1303 | */ |
0e175a18 CW |
1304 | void writeback_inodes_sb_nr(struct super_block *sb, |
1305 | unsigned long nr, | |
1306 | enum wb_reason reason) | |
1da177e4 | 1307 | { |
83ba7b07 CH |
1308 | DECLARE_COMPLETION_ONSTACK(done); |
1309 | struct wb_writeback_work work = { | |
6e6938b6 WF |
1310 | .sb = sb, |
1311 | .sync_mode = WB_SYNC_NONE, | |
1312 | .tagged_writepages = 1, | |
1313 | .done = &done, | |
1314 | .nr_pages = nr, | |
0e175a18 | 1315 | .reason = reason, |
3c4d7165 | 1316 | }; |
d8a8559c | 1317 | |
cf37e972 | 1318 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
83ba7b07 CH |
1319 | bdi_queue_work(sb->s_bdi, &work); |
1320 | wait_for_completion(&done); | |
e913fc82 | 1321 | } |
3259f8be CM |
1322 | EXPORT_SYMBOL(writeback_inodes_sb_nr); |
1323 | ||
1324 | /** | |
1325 | * writeback_inodes_sb - writeback dirty inodes from given super_block | |
1326 | * @sb: the superblock | |
786228ab | 1327 | * @reason: reason why some writeback work was initiated |
3259f8be CM |
1328 | * |
1329 | * Start writeback on some inodes on this super_block. No guarantees are made | |
1330 | * on how many (if any) will be written, and this function does not wait | |
1331 | * for IO completion of submitted IO. | |
1332 | */ | |
0e175a18 | 1333 | void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
3259f8be | 1334 | { |
0e175a18 | 1335 | return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
3259f8be | 1336 | } |
0e3c9a22 | 1337 | EXPORT_SYMBOL(writeback_inodes_sb); |
e913fc82 | 1338 | |
17bd55d0 ES |
1339 | /** |
1340 | * writeback_inodes_sb_if_idle - start writeback if none underway | |
1341 | * @sb: the superblock | |
786228ab | 1342 | * @reason: reason why some writeback work was initiated |
17bd55d0 ES |
1343 | * |
1344 | * Invoke writeback_inodes_sb if no writeback is currently underway. | |
1345 | * Returns 1 if writeback was started, 0 if not. | |
1346 | */ | |
0e175a18 | 1347 | int writeback_inodes_sb_if_idle(struct super_block *sb, enum wb_reason reason) |
17bd55d0 ES |
1348 | { |
1349 | if (!writeback_in_progress(sb->s_bdi)) { | |
cf37e972 | 1350 | down_read(&sb->s_umount); |
0e175a18 | 1351 | writeback_inodes_sb(sb, reason); |
cf37e972 | 1352 | up_read(&sb->s_umount); |
17bd55d0 ES |
1353 | return 1; |
1354 | } else | |
1355 | return 0; | |
1356 | } | |
1357 | EXPORT_SYMBOL(writeback_inodes_sb_if_idle); | |
1358 | ||
3259f8be | 1359 | /** |
c097b2ca | 1360 | * writeback_inodes_sb_nr_if_idle - start writeback if none underway |
3259f8be CM |
1361 | * @sb: the superblock |
1362 | * @nr: the number of pages to write | |
786228ab | 1363 | * @reason: reason why some writeback work was initiated |
3259f8be CM |
1364 | * |
1365 | * Invoke writeback_inodes_sb if no writeback is currently underway. | |
1366 | * Returns 1 if writeback was started, 0 if not. | |
1367 | */ | |
1368 | int writeback_inodes_sb_nr_if_idle(struct super_block *sb, | |
0e175a18 CW |
1369 | unsigned long nr, |
1370 | enum wb_reason reason) | |
3259f8be CM |
1371 | { |
1372 | if (!writeback_in_progress(sb->s_bdi)) { | |
1373 | down_read(&sb->s_umount); | |
0e175a18 | 1374 | writeback_inodes_sb_nr(sb, nr, reason); |
3259f8be CM |
1375 | up_read(&sb->s_umount); |
1376 | return 1; | |
1377 | } else | |
1378 | return 0; | |
1379 | } | |
1380 | EXPORT_SYMBOL(writeback_inodes_sb_nr_if_idle); | |
1381 | ||
d8a8559c JA |
1382 | /** |
1383 | * sync_inodes_sb - sync sb inode pages | |
1384 | * @sb: the superblock | |
1385 | * | |
1386 | * This function writes and waits on any dirty inode belonging to this | |
cb9ef8d5 | 1387 | * super_block. |
d8a8559c | 1388 | */ |
b6e51316 | 1389 | void sync_inodes_sb(struct super_block *sb) |
d8a8559c | 1390 | { |
83ba7b07 CH |
1391 | DECLARE_COMPLETION_ONSTACK(done); |
1392 | struct wb_writeback_work work = { | |
3c4d7165 CH |
1393 | .sb = sb, |
1394 | .sync_mode = WB_SYNC_ALL, | |
1395 | .nr_pages = LONG_MAX, | |
1396 | .range_cyclic = 0, | |
83ba7b07 | 1397 | .done = &done, |
0e175a18 | 1398 | .reason = WB_REASON_SYNC, |
3c4d7165 CH |
1399 | }; |
1400 | ||
cf37e972 CH |
1401 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
1402 | ||
83ba7b07 CH |
1403 | bdi_queue_work(sb->s_bdi, &work); |
1404 | wait_for_completion(&done); | |
1405 | ||
b6e51316 | 1406 | wait_sb_inodes(sb); |
1da177e4 | 1407 | } |
d8a8559c | 1408 | EXPORT_SYMBOL(sync_inodes_sb); |
1da177e4 | 1409 | |
1da177e4 | 1410 | /** |
7f04c26d AA |
1411 | * write_inode_now - write an inode to disk |
1412 | * @inode: inode to write to disk | |
1413 | * @sync: whether the write should be synchronous or not | |
1414 | * | |
1415 | * This function commits an inode to disk immediately if it is dirty. This is | |
1416 | * primarily needed by knfsd. | |
1da177e4 | 1417 | * |
7f04c26d | 1418 | * The caller must either have a ref on the inode or must have set I_WILL_FREE. |
1da177e4 | 1419 | */ |
1da177e4 LT |
1420 | int write_inode_now(struct inode *inode, int sync) |
1421 | { | |
f758eeab | 1422 | struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; |
1da177e4 LT |
1423 | struct writeback_control wbc = { |
1424 | .nr_to_write = LONG_MAX, | |
18914b18 | 1425 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
111ebb6e OH |
1426 | .range_start = 0, |
1427 | .range_end = LLONG_MAX, | |
1da177e4 LT |
1428 | }; |
1429 | ||
1430 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) | |
49364ce2 | 1431 | wbc.nr_to_write = 0; |
1da177e4 LT |
1432 | |
1433 | might_sleep(); | |
4f8ad655 | 1434 | return writeback_single_inode(inode, wb, &wbc); |
1da177e4 LT |
1435 | } |
1436 | EXPORT_SYMBOL(write_inode_now); | |
1437 | ||
1438 | /** | |
1439 | * sync_inode - write an inode and its pages to disk. | |
1440 | * @inode: the inode to sync | |
1441 | * @wbc: controls the writeback mode | |
1442 | * | |
1443 | * sync_inode() will write an inode and its pages to disk. It will also | |
1444 | * correctly update the inode on its superblock's dirty inode lists and will | |
1445 | * update inode->i_state. | |
1446 | * | |
1447 | * The caller must have a ref on the inode. | |
1448 | */ | |
1449 | int sync_inode(struct inode *inode, struct writeback_control *wbc) | |
1450 | { | |
4f8ad655 | 1451 | return writeback_single_inode(inode, &inode_to_bdi(inode)->wb, wbc); |
1da177e4 LT |
1452 | } |
1453 | EXPORT_SYMBOL(sync_inode); | |
c3765016 CH |
1454 | |
1455 | /** | |
c691b9d9 | 1456 | * sync_inode_metadata - write an inode to disk |
c3765016 CH |
1457 | * @inode: the inode to sync |
1458 | * @wait: wait for I/O to complete. | |
1459 | * | |
c691b9d9 | 1460 | * Write an inode to disk and adjust its dirty state after completion. |
c3765016 CH |
1461 | * |
1462 | * Note: only writes the actual inode, no associated data or other metadata. | |
1463 | */ | |
1464 | int sync_inode_metadata(struct inode *inode, int wait) | |
1465 | { | |
1466 | struct writeback_control wbc = { | |
1467 | .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE, | |
1468 | .nr_to_write = 0, /* metadata-only */ | |
1469 | }; | |
1470 | ||
1471 | return sync_inode(inode, &wbc); | |
1472 | } | |
1473 | EXPORT_SYMBOL(sync_inode_metadata); |