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> |
07f3f05c | 29 | #include "internal.h" |
1da177e4 | 30 | |
bc31b86a WF |
31 | /* |
32 | * 4MB minimal write chunk size | |
33 | */ | |
34 | #define MIN_WRITEBACK_PAGES (4096UL >> (PAGE_CACHE_SHIFT - 10)) | |
35 | ||
c4a77a6c JA |
36 | /* |
37 | * Passed into wb_writeback(), essentially a subset of writeback_control | |
38 | */ | |
83ba7b07 | 39 | struct wb_writeback_work { |
c4a77a6c JA |
40 | long nr_pages; |
41 | struct super_block *sb; | |
d46db3d5 | 42 | unsigned long *older_than_this; |
c4a77a6c | 43 | enum writeback_sync_modes sync_mode; |
6e6938b6 | 44 | unsigned int tagged_writepages:1; |
52957fe1 HS |
45 | unsigned int for_kupdate:1; |
46 | unsigned int range_cyclic:1; | |
47 | unsigned int for_background:1; | |
0e175a18 | 48 | enum wb_reason reason; /* why was writeback initiated? */ |
c4a77a6c | 49 | |
8010c3b6 | 50 | struct list_head list; /* pending work list */ |
83ba7b07 | 51 | struct completion *done; /* set if the caller waits */ |
03ba3782 JA |
52 | }; |
53 | ||
f11b00f3 AB |
54 | /** |
55 | * writeback_in_progress - determine whether there is writeback in progress | |
56 | * @bdi: the device's backing_dev_info structure. | |
57 | * | |
03ba3782 JA |
58 | * Determine whether there is writeback waiting to be handled against a |
59 | * backing device. | |
f11b00f3 AB |
60 | */ |
61 | int writeback_in_progress(struct backing_dev_info *bdi) | |
62 | { | |
81d73a32 | 63 | return test_bit(BDI_writeback_running, &bdi->state); |
f11b00f3 | 64 | } |
00d4e736 | 65 | EXPORT_SYMBOL(writeback_in_progress); |
f11b00f3 | 66 | |
692ebd17 JK |
67 | static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) |
68 | { | |
69 | struct super_block *sb = inode->i_sb; | |
692ebd17 | 70 | |
aaead25b CH |
71 | if (strcmp(sb->s_type->name, "bdev") == 0) |
72 | return inode->i_mapping->backing_dev_info; | |
73 | ||
74 | return sb->s_bdi; | |
692ebd17 JK |
75 | } |
76 | ||
7ccf19a8 NP |
77 | static inline struct inode *wb_inode(struct list_head *head) |
78 | { | |
79 | return list_entry(head, struct inode, i_wb_list); | |
80 | } | |
81 | ||
15eb77a0 WF |
82 | /* |
83 | * Include the creation of the trace points after defining the | |
84 | * wb_writeback_work structure and inline functions so that the definition | |
85 | * remains local to this file. | |
86 | */ | |
87 | #define CREATE_TRACE_POINTS | |
88 | #include <trace/events/writeback.h> | |
89 | ||
bf097203 JK |
90 | static void bdi_wakeup_thread(struct backing_dev_info *bdi) |
91 | { | |
92 | spin_lock_bh(&bdi->wb_lock); | |
93 | if (test_bit(BDI_registered, &bdi->state)) | |
94 | mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); | |
95 | spin_unlock_bh(&bdi->wb_lock); | |
96 | } | |
97 | ||
6585027a JK |
98 | static void bdi_queue_work(struct backing_dev_info *bdi, |
99 | struct wb_writeback_work *work) | |
100 | { | |
101 | trace_writeback_queue(bdi, work); | |
102 | ||
103 | spin_lock_bh(&bdi->wb_lock); | |
bf097203 JK |
104 | if (!test_bit(BDI_registered, &bdi->state)) { |
105 | if (work->done) | |
106 | complete(work->done); | |
107 | goto out_unlock; | |
108 | } | |
6585027a | 109 | list_add_tail(&work->list, &bdi->work_list); |
839a8e86 | 110 | mod_delayed_work(bdi_wq, &bdi->wb.dwork, 0); |
bf097203 JK |
111 | out_unlock: |
112 | spin_unlock_bh(&bdi->wb_lock); | |
1da177e4 LT |
113 | } |
114 | ||
83ba7b07 CH |
115 | static void |
116 | __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, | |
0e175a18 | 117 | bool range_cyclic, enum wb_reason reason) |
1da177e4 | 118 | { |
83ba7b07 | 119 | struct wb_writeback_work *work; |
03ba3782 | 120 | |
bcddc3f0 JA |
121 | /* |
122 | * This is WB_SYNC_NONE writeback, so if allocation fails just | |
123 | * wakeup the thread for old dirty data writeback | |
124 | */ | |
83ba7b07 CH |
125 | work = kzalloc(sizeof(*work), GFP_ATOMIC); |
126 | if (!work) { | |
839a8e86 | 127 | trace_writeback_nowork(bdi); |
bf097203 | 128 | bdi_wakeup_thread(bdi); |
83ba7b07 | 129 | return; |
bcddc3f0 | 130 | } |
03ba3782 | 131 | |
83ba7b07 CH |
132 | work->sync_mode = WB_SYNC_NONE; |
133 | work->nr_pages = nr_pages; | |
134 | work->range_cyclic = range_cyclic; | |
0e175a18 | 135 | work->reason = reason; |
03ba3782 | 136 | |
83ba7b07 | 137 | bdi_queue_work(bdi, work); |
b6e51316 JA |
138 | } |
139 | ||
140 | /** | |
141 | * bdi_start_writeback - start writeback | |
142 | * @bdi: the backing device to write from | |
143 | * @nr_pages: the number of pages to write | |
786228ab | 144 | * @reason: reason why some writeback work was initiated |
b6e51316 JA |
145 | * |
146 | * Description: | |
147 | * This does WB_SYNC_NONE opportunistic writeback. The IO is only | |
25985edc | 148 | * started when this function returns, we make no guarantees on |
0e3c9a22 | 149 | * completion. Caller need not hold sb s_umount semaphore. |
b6e51316 JA |
150 | * |
151 | */ | |
0e175a18 CW |
152 | void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages, |
153 | enum wb_reason reason) | |
b6e51316 | 154 | { |
0e175a18 | 155 | __bdi_start_writeback(bdi, nr_pages, true, reason); |
c5444198 | 156 | } |
d3ddec76 | 157 | |
c5444198 CH |
158 | /** |
159 | * bdi_start_background_writeback - start background writeback | |
160 | * @bdi: the backing device to write from | |
161 | * | |
162 | * Description: | |
6585027a JK |
163 | * This makes sure WB_SYNC_NONE background writeback happens. When |
164 | * this function returns, it is only guaranteed that for given BDI | |
165 | * some IO is happening if we are over background dirty threshold. | |
166 | * Caller need not hold sb s_umount semaphore. | |
c5444198 CH |
167 | */ |
168 | void bdi_start_background_writeback(struct backing_dev_info *bdi) | |
169 | { | |
6585027a JK |
170 | /* |
171 | * We just wake up the flusher thread. It will perform background | |
172 | * writeback as soon as there is no other work to do. | |
173 | */ | |
71927e84 | 174 | trace_writeback_wake_background(bdi); |
bf097203 | 175 | bdi_wakeup_thread(bdi); |
1da177e4 LT |
176 | } |
177 | ||
a66979ab DC |
178 | /* |
179 | * Remove the inode from the writeback list it is on. | |
180 | */ | |
181 | void inode_wb_list_del(struct inode *inode) | |
182 | { | |
f758eeab CH |
183 | struct backing_dev_info *bdi = inode_to_bdi(inode); |
184 | ||
185 | spin_lock(&bdi->wb.list_lock); | |
a66979ab | 186 | list_del_init(&inode->i_wb_list); |
f758eeab | 187 | spin_unlock(&bdi->wb.list_lock); |
a66979ab DC |
188 | } |
189 | ||
6610a0bc AM |
190 | /* |
191 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the | |
192 | * furthest end of its superblock's dirty-inode list. | |
193 | * | |
194 | * Before stamping the inode's ->dirtied_when, we check to see whether it is | |
66f3b8e2 | 195 | * already the most-recently-dirtied inode on the b_dirty list. If that is |
6610a0bc AM |
196 | * the case then the inode must have been redirtied while it was being written |
197 | * out and we don't reset its dirtied_when. | |
198 | */ | |
f758eeab | 199 | static void redirty_tail(struct inode *inode, struct bdi_writeback *wb) |
6610a0bc | 200 | { |
f758eeab | 201 | assert_spin_locked(&wb->list_lock); |
03ba3782 | 202 | if (!list_empty(&wb->b_dirty)) { |
66f3b8e2 | 203 | struct inode *tail; |
6610a0bc | 204 | |
7ccf19a8 | 205 | tail = wb_inode(wb->b_dirty.next); |
66f3b8e2 | 206 | if (time_before(inode->dirtied_when, tail->dirtied_when)) |
6610a0bc AM |
207 | inode->dirtied_when = jiffies; |
208 | } | |
7ccf19a8 | 209 | list_move(&inode->i_wb_list, &wb->b_dirty); |
6610a0bc AM |
210 | } |
211 | ||
c986d1e2 | 212 | /* |
66f3b8e2 | 213 | * requeue inode for re-scanning after bdi->b_io list is exhausted. |
c986d1e2 | 214 | */ |
f758eeab | 215 | static void requeue_io(struct inode *inode, struct bdi_writeback *wb) |
c986d1e2 | 216 | { |
f758eeab | 217 | assert_spin_locked(&wb->list_lock); |
7ccf19a8 | 218 | list_move(&inode->i_wb_list, &wb->b_more_io); |
c986d1e2 AM |
219 | } |
220 | ||
1c0eeaf5 JE |
221 | static void inode_sync_complete(struct inode *inode) |
222 | { | |
365b94ae | 223 | inode->i_state &= ~I_SYNC; |
4eff96dd JK |
224 | /* If inode is clean an unused, put it into LRU now... */ |
225 | inode_add_lru(inode); | |
365b94ae | 226 | /* Waiters must see I_SYNC cleared before being woken up */ |
1c0eeaf5 JE |
227 | smp_mb(); |
228 | wake_up_bit(&inode->i_state, __I_SYNC); | |
229 | } | |
230 | ||
d2caa3c5 JL |
231 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
232 | { | |
233 | bool ret = time_after(inode->dirtied_when, t); | |
234 | #ifndef CONFIG_64BIT | |
235 | /* | |
236 | * For inodes being constantly redirtied, dirtied_when can get stuck. | |
237 | * It _appears_ to be in the future, but is actually in distant past. | |
238 | * This test is necessary to prevent such wrapped-around relative times | |
5b0830cb | 239 | * from permanently stopping the whole bdi writeback. |
d2caa3c5 JL |
240 | */ |
241 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); | |
242 | #endif | |
243 | return ret; | |
244 | } | |
245 | ||
2c136579 | 246 | /* |
0e2f2b23 | 247 | * Move expired (dirtied before work->older_than_this) dirty inodes from |
697e6fed | 248 | * @delaying_queue to @dispatch_queue. |
2c136579 | 249 | */ |
e84d0a4f | 250 | static int move_expired_inodes(struct list_head *delaying_queue, |
2c136579 | 251 | struct list_head *dispatch_queue, |
ad4e38dd | 252 | struct wb_writeback_work *work) |
2c136579 | 253 | { |
5c03449d SL |
254 | LIST_HEAD(tmp); |
255 | struct list_head *pos, *node; | |
cf137307 | 256 | struct super_block *sb = NULL; |
5c03449d | 257 | struct inode *inode; |
cf137307 | 258 | int do_sb_sort = 0; |
e84d0a4f | 259 | int moved = 0; |
5c03449d | 260 | |
2c136579 | 261 | while (!list_empty(delaying_queue)) { |
7ccf19a8 | 262 | inode = wb_inode(delaying_queue->prev); |
ad4e38dd CW |
263 | if (work->older_than_this && |
264 | inode_dirtied_after(inode, *work->older_than_this)) | |
2c136579 | 265 | break; |
cf137307 JA |
266 | if (sb && sb != inode->i_sb) |
267 | do_sb_sort = 1; | |
268 | sb = inode->i_sb; | |
7ccf19a8 | 269 | list_move(&inode->i_wb_list, &tmp); |
e84d0a4f | 270 | moved++; |
5c03449d SL |
271 | } |
272 | ||
cf137307 JA |
273 | /* just one sb in list, splice to dispatch_queue and we're done */ |
274 | if (!do_sb_sort) { | |
275 | list_splice(&tmp, dispatch_queue); | |
e84d0a4f | 276 | goto out; |
cf137307 JA |
277 | } |
278 | ||
5c03449d SL |
279 | /* Move inodes from one superblock together */ |
280 | while (!list_empty(&tmp)) { | |
7ccf19a8 | 281 | sb = wb_inode(tmp.prev)->i_sb; |
5c03449d | 282 | list_for_each_prev_safe(pos, node, &tmp) { |
7ccf19a8 | 283 | inode = wb_inode(pos); |
5c03449d | 284 | if (inode->i_sb == sb) |
7ccf19a8 | 285 | list_move(&inode->i_wb_list, dispatch_queue); |
5c03449d | 286 | } |
2c136579 | 287 | } |
e84d0a4f WF |
288 | out: |
289 | return moved; | |
2c136579 FW |
290 | } |
291 | ||
292 | /* | |
293 | * Queue all expired dirty inodes for io, eldest first. | |
4ea879b9 WF |
294 | * Before |
295 | * newly dirtied b_dirty b_io b_more_io | |
296 | * =============> gf edc BA | |
297 | * After | |
298 | * newly dirtied b_dirty b_io b_more_io | |
299 | * =============> g fBAedc | |
300 | * | | |
301 | * +--> dequeue for IO | |
2c136579 | 302 | */ |
ad4e38dd | 303 | static void queue_io(struct bdi_writeback *wb, struct wb_writeback_work *work) |
66f3b8e2 | 304 | { |
e84d0a4f | 305 | int moved; |
f758eeab | 306 | assert_spin_locked(&wb->list_lock); |
4ea879b9 | 307 | list_splice_init(&wb->b_more_io, &wb->b_io); |
ad4e38dd CW |
308 | moved = move_expired_inodes(&wb->b_dirty, &wb->b_io, work); |
309 | trace_writeback_queue_io(wb, work, moved); | |
66f3b8e2 JA |
310 | } |
311 | ||
a9185b41 | 312 | static int write_inode(struct inode *inode, struct writeback_control *wbc) |
08d8e974 | 313 | { |
9fb0a7da TH |
314 | int ret; |
315 | ||
316 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) { | |
317 | trace_writeback_write_inode_start(inode, wbc); | |
318 | ret = inode->i_sb->s_op->write_inode(inode, wbc); | |
319 | trace_writeback_write_inode(inode, wbc); | |
320 | return ret; | |
321 | } | |
03ba3782 | 322 | return 0; |
08d8e974 | 323 | } |
08d8e974 | 324 | |
1da177e4 | 325 | /* |
169ebd90 JK |
326 | * Wait for writeback on an inode to complete. Called with i_lock held. |
327 | * Caller must make sure inode cannot go away when we drop i_lock. | |
01c03194 | 328 | */ |
169ebd90 JK |
329 | static void __inode_wait_for_writeback(struct inode *inode) |
330 | __releases(inode->i_lock) | |
331 | __acquires(inode->i_lock) | |
01c03194 CH |
332 | { |
333 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); | |
334 | wait_queue_head_t *wqh; | |
335 | ||
336 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
250df6ed DC |
337 | while (inode->i_state & I_SYNC) { |
338 | spin_unlock(&inode->i_lock); | |
01c03194 | 339 | __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); |
250df6ed | 340 | spin_lock(&inode->i_lock); |
58a9d3d8 | 341 | } |
01c03194 CH |
342 | } |
343 | ||
169ebd90 JK |
344 | /* |
345 | * Wait for writeback on an inode to complete. Caller must have inode pinned. | |
346 | */ | |
347 | void inode_wait_for_writeback(struct inode *inode) | |
348 | { | |
349 | spin_lock(&inode->i_lock); | |
350 | __inode_wait_for_writeback(inode); | |
351 | spin_unlock(&inode->i_lock); | |
352 | } | |
353 | ||
354 | /* | |
355 | * Sleep until I_SYNC is cleared. This function must be called with i_lock | |
356 | * held and drops it. It is aimed for callers not holding any inode reference | |
357 | * so once i_lock is dropped, inode can go away. | |
358 | */ | |
359 | static void inode_sleep_on_writeback(struct inode *inode) | |
360 | __releases(inode->i_lock) | |
361 | { | |
362 | DEFINE_WAIT(wait); | |
363 | wait_queue_head_t *wqh = bit_waitqueue(&inode->i_state, __I_SYNC); | |
364 | int sleep; | |
365 | ||
366 | prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); | |
367 | sleep = inode->i_state & I_SYNC; | |
368 | spin_unlock(&inode->i_lock); | |
369 | if (sleep) | |
370 | schedule(); | |
371 | finish_wait(wqh, &wait); | |
372 | } | |
373 | ||
ccb26b5a JK |
374 | /* |
375 | * Find proper writeback list for the inode depending on its current state and | |
376 | * possibly also change of its state while we were doing writeback. Here we | |
377 | * handle things such as livelock prevention or fairness of writeback among | |
378 | * inodes. This function can be called only by flusher thread - noone else | |
379 | * processes all inodes in writeback lists and requeueing inodes behind flusher | |
380 | * thread's back can have unexpected consequences. | |
381 | */ | |
382 | static void requeue_inode(struct inode *inode, struct bdi_writeback *wb, | |
383 | struct writeback_control *wbc) | |
384 | { | |
385 | if (inode->i_state & I_FREEING) | |
386 | return; | |
387 | ||
388 | /* | |
389 | * Sync livelock prevention. Each inode is tagged and synced in one | |
390 | * shot. If still dirty, it will be redirty_tail()'ed below. Update | |
391 | * the dirty time to prevent enqueue and sync it again. | |
392 | */ | |
393 | if ((inode->i_state & I_DIRTY) && | |
394 | (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)) | |
395 | inode->dirtied_when = jiffies; | |
396 | ||
4f8ad655 JK |
397 | if (wbc->pages_skipped) { |
398 | /* | |
399 | * writeback is not making progress due to locked | |
400 | * buffers. Skip this inode for now. | |
401 | */ | |
402 | redirty_tail(inode, wb); | |
403 | return; | |
404 | } | |
405 | ||
ccb26b5a JK |
406 | if (mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) { |
407 | /* | |
408 | * We didn't write back all the pages. nfs_writepages() | |
409 | * sometimes bales out without doing anything. | |
410 | */ | |
411 | if (wbc->nr_to_write <= 0) { | |
412 | /* Slice used up. Queue for next turn. */ | |
413 | requeue_io(inode, wb); | |
414 | } else { | |
415 | /* | |
416 | * Writeback blocked by something other than | |
417 | * congestion. Delay the inode for some time to | |
418 | * avoid spinning on the CPU (100% iowait) | |
419 | * retrying writeback of the dirty page/inode | |
420 | * that cannot be performed immediately. | |
421 | */ | |
422 | redirty_tail(inode, wb); | |
423 | } | |
424 | } else if (inode->i_state & I_DIRTY) { | |
425 | /* | |
426 | * Filesystems can dirty the inode during writeback operations, | |
427 | * such as delayed allocation during submission or metadata | |
428 | * updates after data IO completion. | |
429 | */ | |
430 | redirty_tail(inode, wb); | |
431 | } else { | |
432 | /* The inode is clean. Remove from writeback lists. */ | |
433 | list_del_init(&inode->i_wb_list); | |
434 | } | |
435 | } | |
436 | ||
01c03194 | 437 | /* |
4f8ad655 JK |
438 | * Write out an inode and its dirty pages. Do not update the writeback list |
439 | * linkage. That is left to the caller. The caller is also responsible for | |
440 | * setting I_SYNC flag and calling inode_sync_complete() to clear it. | |
1da177e4 LT |
441 | */ |
442 | static int | |
cd8ed2a4 | 443 | __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
1da177e4 | 444 | { |
1da177e4 | 445 | struct address_space *mapping = inode->i_mapping; |
251d6a47 | 446 | long nr_to_write = wbc->nr_to_write; |
01c03194 | 447 | unsigned dirty; |
1da177e4 LT |
448 | int ret; |
449 | ||
4f8ad655 | 450 | WARN_ON(!(inode->i_state & I_SYNC)); |
1da177e4 | 451 | |
9fb0a7da TH |
452 | trace_writeback_single_inode_start(inode, wbc, nr_to_write); |
453 | ||
1da177e4 LT |
454 | ret = do_writepages(mapping, wbc); |
455 | ||
26821ed4 CH |
456 | /* |
457 | * Make sure to wait on the data before writing out the metadata. | |
458 | * This is important for filesystems that modify metadata on data | |
459 | * I/O completion. | |
460 | */ | |
a9185b41 | 461 | if (wbc->sync_mode == WB_SYNC_ALL) { |
26821ed4 | 462 | int err = filemap_fdatawait(mapping); |
1da177e4 LT |
463 | if (ret == 0) |
464 | ret = err; | |
465 | } | |
466 | ||
5547e8aa DM |
467 | /* |
468 | * Some filesystems may redirty the inode during the writeback | |
469 | * due to delalloc, clear dirty metadata flags right before | |
470 | * write_inode() | |
471 | */ | |
250df6ed | 472 | spin_lock(&inode->i_lock); |
21fe2674 | 473 | |
5547e8aa | 474 | dirty = inode->i_state & I_DIRTY; |
21fe2674 TH |
475 | inode->i_state &= ~I_DIRTY; |
476 | ||
477 | /* | |
478 | * Paired with smp_mb() in __mark_inode_dirty(). This allows | |
479 | * __mark_inode_dirty() to test i_state without grabbing i_lock - | |
480 | * either they see the I_DIRTY bits cleared or we see the dirtied | |
481 | * inode. | |
482 | * | |
483 | * I_DIRTY_PAGES is always cleared together above even if @mapping | |
484 | * still has dirty pages. The flag is reinstated after smp_mb() if | |
485 | * necessary. This guarantees that either __mark_inode_dirty() | |
486 | * sees clear I_DIRTY_PAGES or we see PAGECACHE_TAG_DIRTY. | |
487 | */ | |
488 | smp_mb(); | |
489 | ||
490 | if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) | |
491 | inode->i_state |= I_DIRTY_PAGES; | |
492 | ||
250df6ed | 493 | spin_unlock(&inode->i_lock); |
21fe2674 | 494 | |
26821ed4 CH |
495 | /* Don't write the inode if only I_DIRTY_PAGES was set */ |
496 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
a9185b41 | 497 | int err = write_inode(inode, wbc); |
1da177e4 LT |
498 | if (ret == 0) |
499 | ret = err; | |
500 | } | |
4f8ad655 JK |
501 | trace_writeback_single_inode(inode, wbc, nr_to_write); |
502 | return ret; | |
503 | } | |
504 | ||
505 | /* | |
506 | * Write out an inode's dirty pages. Either the caller has an active reference | |
507 | * on the inode or the inode has I_WILL_FREE set. | |
508 | * | |
509 | * This function is designed to be called for writing back one inode which | |
510 | * we go e.g. from filesystem. Flusher thread uses __writeback_single_inode() | |
511 | * and does more profound writeback list handling in writeback_sb_inodes(). | |
512 | */ | |
513 | static int | |
514 | writeback_single_inode(struct inode *inode, struct bdi_writeback *wb, | |
515 | struct writeback_control *wbc) | |
516 | { | |
517 | int ret = 0; | |
518 | ||
519 | spin_lock(&inode->i_lock); | |
520 | if (!atomic_read(&inode->i_count)) | |
521 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); | |
522 | else | |
523 | WARN_ON(inode->i_state & I_WILL_FREE); | |
524 | ||
525 | if (inode->i_state & I_SYNC) { | |
526 | if (wbc->sync_mode != WB_SYNC_ALL) | |
527 | goto out; | |
528 | /* | |
169ebd90 JK |
529 | * It's a data-integrity sync. We must wait. Since callers hold |
530 | * inode reference or inode has I_WILL_FREE set, it cannot go | |
531 | * away under us. | |
4f8ad655 | 532 | */ |
169ebd90 | 533 | __inode_wait_for_writeback(inode); |
4f8ad655 JK |
534 | } |
535 | WARN_ON(inode->i_state & I_SYNC); | |
536 | /* | |
cc46cb33 JK |
537 | * Skip inode if it is clean and we have no outstanding writeback in |
538 | * WB_SYNC_ALL mode. We don't want to mess with writeback lists in this | |
539 | * function since flusher thread may be doing for example sync in | |
540 | * parallel and if we move the inode, it could get skipped. So here we | |
541 | * make sure inode is on some writeback list and leave it there unless | |
542 | * we have completely cleaned the inode. | |
4f8ad655 | 543 | */ |
cc46cb33 JK |
544 | if (!(inode->i_state & I_DIRTY) && |
545 | (wbc->sync_mode != WB_SYNC_ALL || | |
546 | !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_WRITEBACK))) | |
4f8ad655 JK |
547 | goto out; |
548 | inode->i_state |= I_SYNC; | |
549 | spin_unlock(&inode->i_lock); | |
550 | ||
cd8ed2a4 | 551 | ret = __writeback_single_inode(inode, wbc); |
1da177e4 | 552 | |
f758eeab | 553 | spin_lock(&wb->list_lock); |
250df6ed | 554 | spin_lock(&inode->i_lock); |
4f8ad655 JK |
555 | /* |
556 | * If inode is clean, remove it from writeback lists. Otherwise don't | |
557 | * touch it. See comment above for explanation. | |
558 | */ | |
559 | if (!(inode->i_state & I_DIRTY)) | |
560 | list_del_init(&inode->i_wb_list); | |
561 | spin_unlock(&wb->list_lock); | |
1c0eeaf5 | 562 | inode_sync_complete(inode); |
4f8ad655 JK |
563 | out: |
564 | spin_unlock(&inode->i_lock); | |
1da177e4 LT |
565 | return ret; |
566 | } | |
567 | ||
1a12d8bd WF |
568 | static long writeback_chunk_size(struct backing_dev_info *bdi, |
569 | struct wb_writeback_work *work) | |
d46db3d5 WF |
570 | { |
571 | long pages; | |
572 | ||
573 | /* | |
574 | * WB_SYNC_ALL mode does livelock avoidance by syncing dirty | |
575 | * inodes/pages in one big loop. Setting wbc.nr_to_write=LONG_MAX | |
576 | * here avoids calling into writeback_inodes_wb() more than once. | |
577 | * | |
578 | * The intended call sequence for WB_SYNC_ALL writeback is: | |
579 | * | |
580 | * wb_writeback() | |
581 | * writeback_sb_inodes() <== called only once | |
582 | * write_cache_pages() <== called once for each inode | |
583 | * (quickly) tag currently dirty pages | |
584 | * (maybe slowly) sync all tagged pages | |
585 | */ | |
586 | if (work->sync_mode == WB_SYNC_ALL || work->tagged_writepages) | |
587 | pages = LONG_MAX; | |
1a12d8bd WF |
588 | else { |
589 | pages = min(bdi->avg_write_bandwidth / 2, | |
590 | global_dirty_limit / DIRTY_SCOPE); | |
591 | pages = min(pages, work->nr_pages); | |
592 | pages = round_down(pages + MIN_WRITEBACK_PAGES, | |
593 | MIN_WRITEBACK_PAGES); | |
594 | } | |
d46db3d5 WF |
595 | |
596 | return pages; | |
597 | } | |
598 | ||
f11c9c5c ES |
599 | /* |
600 | * Write a portion of b_io inodes which belong to @sb. | |
edadfb10 | 601 | * |
d46db3d5 | 602 | * Return the number of pages and/or inodes written. |
f11c9c5c | 603 | */ |
d46db3d5 WF |
604 | static long writeback_sb_inodes(struct super_block *sb, |
605 | struct bdi_writeback *wb, | |
606 | struct wb_writeback_work *work) | |
1da177e4 | 607 | { |
d46db3d5 WF |
608 | struct writeback_control wbc = { |
609 | .sync_mode = work->sync_mode, | |
610 | .tagged_writepages = work->tagged_writepages, | |
611 | .for_kupdate = work->for_kupdate, | |
612 | .for_background = work->for_background, | |
613 | .range_cyclic = work->range_cyclic, | |
614 | .range_start = 0, | |
615 | .range_end = LLONG_MAX, | |
616 | }; | |
617 | unsigned long start_time = jiffies; | |
618 | long write_chunk; | |
619 | long wrote = 0; /* count both pages and inodes */ | |
620 | ||
03ba3782 | 621 | while (!list_empty(&wb->b_io)) { |
7ccf19a8 | 622 | struct inode *inode = wb_inode(wb->b_io.prev); |
edadfb10 CH |
623 | |
624 | if (inode->i_sb != sb) { | |
d46db3d5 | 625 | if (work->sb) { |
edadfb10 CH |
626 | /* |
627 | * We only want to write back data for this | |
628 | * superblock, move all inodes not belonging | |
629 | * to it back onto the dirty list. | |
630 | */ | |
f758eeab | 631 | redirty_tail(inode, wb); |
edadfb10 CH |
632 | continue; |
633 | } | |
634 | ||
635 | /* | |
636 | * The inode belongs to a different superblock. | |
637 | * Bounce back to the caller to unpin this and | |
638 | * pin the next superblock. | |
639 | */ | |
d46db3d5 | 640 | break; |
edadfb10 CH |
641 | } |
642 | ||
9843b76a | 643 | /* |
331cbdee WL |
644 | * Don't bother with new inodes or inodes being freed, first |
645 | * kind does not need periodic writeout yet, and for the latter | |
9843b76a CH |
646 | * kind writeout is handled by the freer. |
647 | */ | |
250df6ed | 648 | spin_lock(&inode->i_lock); |
9843b76a | 649 | if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) { |
250df6ed | 650 | spin_unlock(&inode->i_lock); |
fcc5c222 | 651 | redirty_tail(inode, wb); |
7ef0d737 NP |
652 | continue; |
653 | } | |
cc1676d9 JK |
654 | if ((inode->i_state & I_SYNC) && wbc.sync_mode != WB_SYNC_ALL) { |
655 | /* | |
656 | * If this inode is locked for writeback and we are not | |
657 | * doing writeback-for-data-integrity, move it to | |
658 | * b_more_io so that writeback can proceed with the | |
659 | * other inodes on s_io. | |
660 | * | |
661 | * We'll have another go at writing back this inode | |
662 | * when we completed a full scan of b_io. | |
663 | */ | |
664 | spin_unlock(&inode->i_lock); | |
665 | requeue_io(inode, wb); | |
666 | trace_writeback_sb_inodes_requeue(inode); | |
667 | continue; | |
668 | } | |
f0d07b7f JK |
669 | spin_unlock(&wb->list_lock); |
670 | ||
4f8ad655 JK |
671 | /* |
672 | * We already requeued the inode if it had I_SYNC set and we | |
673 | * are doing WB_SYNC_NONE writeback. So this catches only the | |
674 | * WB_SYNC_ALL case. | |
675 | */ | |
169ebd90 JK |
676 | if (inode->i_state & I_SYNC) { |
677 | /* Wait for I_SYNC. This function drops i_lock... */ | |
678 | inode_sleep_on_writeback(inode); | |
679 | /* Inode may be gone, start again */ | |
ead188f9 | 680 | spin_lock(&wb->list_lock); |
169ebd90 JK |
681 | continue; |
682 | } | |
4f8ad655 JK |
683 | inode->i_state |= I_SYNC; |
684 | spin_unlock(&inode->i_lock); | |
169ebd90 | 685 | |
1a12d8bd | 686 | write_chunk = writeback_chunk_size(wb->bdi, work); |
d46db3d5 WF |
687 | wbc.nr_to_write = write_chunk; |
688 | wbc.pages_skipped = 0; | |
250df6ed | 689 | |
169ebd90 JK |
690 | /* |
691 | * We use I_SYNC to pin the inode in memory. While it is set | |
692 | * evict_inode() will wait so the inode cannot be freed. | |
693 | */ | |
cd8ed2a4 | 694 | __writeback_single_inode(inode, &wbc); |
250df6ed | 695 | |
d46db3d5 WF |
696 | work->nr_pages -= write_chunk - wbc.nr_to_write; |
697 | wrote += write_chunk - wbc.nr_to_write; | |
4f8ad655 JK |
698 | spin_lock(&wb->list_lock); |
699 | spin_lock(&inode->i_lock); | |
d46db3d5 WF |
700 | if (!(inode->i_state & I_DIRTY)) |
701 | wrote++; | |
4f8ad655 JK |
702 | requeue_inode(inode, wb, &wbc); |
703 | inode_sync_complete(inode); | |
0f1b1fd8 | 704 | spin_unlock(&inode->i_lock); |
169ebd90 | 705 | cond_resched_lock(&wb->list_lock); |
d46db3d5 WF |
706 | /* |
707 | * bail out to wb_writeback() often enough to check | |
708 | * background threshold and other termination conditions. | |
709 | */ | |
710 | if (wrote) { | |
711 | if (time_is_before_jiffies(start_time + HZ / 10UL)) | |
712 | break; | |
713 | if (work->nr_pages <= 0) | |
714 | break; | |
8bc3be27 | 715 | } |
1da177e4 | 716 | } |
d46db3d5 | 717 | return wrote; |
f11c9c5c ES |
718 | } |
719 | ||
d46db3d5 WF |
720 | static long __writeback_inodes_wb(struct bdi_writeback *wb, |
721 | struct wb_writeback_work *work) | |
f11c9c5c | 722 | { |
d46db3d5 WF |
723 | unsigned long start_time = jiffies; |
724 | long wrote = 0; | |
38f21977 | 725 | |
f11c9c5c | 726 | while (!list_empty(&wb->b_io)) { |
7ccf19a8 | 727 | struct inode *inode = wb_inode(wb->b_io.prev); |
f11c9c5c | 728 | struct super_block *sb = inode->i_sb; |
9ecc2738 | 729 | |
12ad3ab6 | 730 | if (!grab_super_passive(sb)) { |
0e995816 WF |
731 | /* |
732 | * grab_super_passive() may fail consistently due to | |
733 | * s_umount being grabbed by someone else. Don't use | |
734 | * requeue_io() to avoid busy retrying the inode/sb. | |
735 | */ | |
736 | redirty_tail(inode, wb); | |
edadfb10 | 737 | continue; |
f11c9c5c | 738 | } |
d46db3d5 | 739 | wrote += writeback_sb_inodes(sb, wb, work); |
edadfb10 | 740 | drop_super(sb); |
f11c9c5c | 741 | |
d46db3d5 WF |
742 | /* refer to the same tests at the end of writeback_sb_inodes */ |
743 | if (wrote) { | |
744 | if (time_is_before_jiffies(start_time + HZ / 10UL)) | |
745 | break; | |
746 | if (work->nr_pages <= 0) | |
747 | break; | |
748 | } | |
f11c9c5c | 749 | } |
66f3b8e2 | 750 | /* Leave any unwritten inodes on b_io */ |
d46db3d5 | 751 | return wrote; |
66f3b8e2 JA |
752 | } |
753 | ||
0e175a18 CW |
754 | long writeback_inodes_wb(struct bdi_writeback *wb, long nr_pages, |
755 | enum wb_reason reason) | |
edadfb10 | 756 | { |
d46db3d5 WF |
757 | struct wb_writeback_work work = { |
758 | .nr_pages = nr_pages, | |
759 | .sync_mode = WB_SYNC_NONE, | |
760 | .range_cyclic = 1, | |
0e175a18 | 761 | .reason = reason, |
d46db3d5 | 762 | }; |
edadfb10 | 763 | |
f758eeab | 764 | spin_lock(&wb->list_lock); |
424b351f | 765 | if (list_empty(&wb->b_io)) |
ad4e38dd | 766 | queue_io(wb, &work); |
d46db3d5 | 767 | __writeback_inodes_wb(wb, &work); |
f758eeab | 768 | spin_unlock(&wb->list_lock); |
edadfb10 | 769 | |
d46db3d5 WF |
770 | return nr_pages - work.nr_pages; |
771 | } | |
03ba3782 | 772 | |
b00949aa | 773 | static bool over_bground_thresh(struct backing_dev_info *bdi) |
03ba3782 JA |
774 | { |
775 | unsigned long background_thresh, dirty_thresh; | |
776 | ||
16c4042f | 777 | global_dirty_limits(&background_thresh, &dirty_thresh); |
03ba3782 | 778 | |
b00949aa WF |
779 | if (global_page_state(NR_FILE_DIRTY) + |
780 | global_page_state(NR_UNSTABLE_NFS) > background_thresh) | |
781 | return true; | |
782 | ||
783 | if (bdi_stat(bdi, BDI_RECLAIMABLE) > | |
784 | bdi_dirty_limit(bdi, background_thresh)) | |
785 | return true; | |
786 | ||
787 | return false; | |
03ba3782 JA |
788 | } |
789 | ||
e98be2d5 WF |
790 | /* |
791 | * Called under wb->list_lock. If there are multiple wb per bdi, | |
792 | * only the flusher working on the first wb should do it. | |
793 | */ | |
794 | static void wb_update_bandwidth(struct bdi_writeback *wb, | |
795 | unsigned long start_time) | |
796 | { | |
af6a3113 | 797 | __bdi_update_bandwidth(wb->bdi, 0, 0, 0, 0, 0, start_time); |
e98be2d5 WF |
798 | } |
799 | ||
03ba3782 JA |
800 | /* |
801 | * Explicit flushing or periodic writeback of "old" data. | |
66f3b8e2 | 802 | * |
03ba3782 JA |
803 | * Define "old": the first time one of an inode's pages is dirtied, we mark the |
804 | * dirtying-time in the inode's address_space. So this periodic writeback code | |
805 | * just walks the superblock inode list, writing back any inodes which are | |
806 | * older than a specific point in time. | |
66f3b8e2 | 807 | * |
03ba3782 JA |
808 | * Try to run once per dirty_writeback_interval. But if a writeback event |
809 | * takes longer than a dirty_writeback_interval interval, then leave a | |
810 | * one-second gap. | |
66f3b8e2 | 811 | * |
03ba3782 JA |
812 | * older_than_this takes precedence over nr_to_write. So we'll only write back |
813 | * all dirty pages if they are all attached to "old" mappings. | |
66f3b8e2 | 814 | */ |
c4a77a6c | 815 | static long wb_writeback(struct bdi_writeback *wb, |
83ba7b07 | 816 | struct wb_writeback_work *work) |
66f3b8e2 | 817 | { |
e98be2d5 | 818 | unsigned long wb_start = jiffies; |
d46db3d5 | 819 | long nr_pages = work->nr_pages; |
03ba3782 | 820 | unsigned long oldest_jif; |
a5989bdc | 821 | struct inode *inode; |
d46db3d5 | 822 | long progress; |
66f3b8e2 | 823 | |
e185dda8 | 824 | oldest_jif = jiffies; |
d46db3d5 | 825 | work->older_than_this = &oldest_jif; |
38f21977 | 826 | |
e8dfc305 | 827 | spin_lock(&wb->list_lock); |
03ba3782 JA |
828 | for (;;) { |
829 | /* | |
d3ddec76 | 830 | * Stop writeback when nr_pages has been consumed |
03ba3782 | 831 | */ |
83ba7b07 | 832 | if (work->nr_pages <= 0) |
03ba3782 | 833 | break; |
66f3b8e2 | 834 | |
aa373cf5 JK |
835 | /* |
836 | * Background writeout and kupdate-style writeback may | |
837 | * run forever. Stop them if there is other work to do | |
838 | * so that e.g. sync can proceed. They'll be restarted | |
839 | * after the other works are all done. | |
840 | */ | |
841 | if ((work->for_background || work->for_kupdate) && | |
842 | !list_empty(&wb->bdi->work_list)) | |
843 | break; | |
844 | ||
38f21977 | 845 | /* |
d3ddec76 WF |
846 | * For background writeout, stop when we are below the |
847 | * background dirty threshold | |
38f21977 | 848 | */ |
b00949aa | 849 | if (work->for_background && !over_bground_thresh(wb->bdi)) |
03ba3782 | 850 | break; |
38f21977 | 851 | |
1bc36b64 JK |
852 | /* |
853 | * Kupdate and background works are special and we want to | |
854 | * include all inodes that need writing. Livelock avoidance is | |
855 | * handled by these works yielding to any other work so we are | |
856 | * safe. | |
857 | */ | |
ba9aa839 WF |
858 | if (work->for_kupdate) { |
859 | oldest_jif = jiffies - | |
860 | msecs_to_jiffies(dirty_expire_interval * 10); | |
1bc36b64 JK |
861 | } else if (work->for_background) |
862 | oldest_jif = jiffies; | |
028c2dd1 | 863 | |
d46db3d5 | 864 | trace_writeback_start(wb->bdi, work); |
e8dfc305 | 865 | if (list_empty(&wb->b_io)) |
ad4e38dd | 866 | queue_io(wb, work); |
83ba7b07 | 867 | if (work->sb) |
d46db3d5 | 868 | progress = writeback_sb_inodes(work->sb, wb, work); |
edadfb10 | 869 | else |
d46db3d5 WF |
870 | progress = __writeback_inodes_wb(wb, work); |
871 | trace_writeback_written(wb->bdi, work); | |
028c2dd1 | 872 | |
e98be2d5 | 873 | wb_update_bandwidth(wb, wb_start); |
03ba3782 JA |
874 | |
875 | /* | |
e6fb6da2 WF |
876 | * Did we write something? Try for more |
877 | * | |
878 | * Dirty inodes are moved to b_io for writeback in batches. | |
879 | * The completion of the current batch does not necessarily | |
880 | * mean the overall work is done. So we keep looping as long | |
881 | * as made some progress on cleaning pages or inodes. | |
03ba3782 | 882 | */ |
d46db3d5 | 883 | if (progress) |
71fd05a8 JA |
884 | continue; |
885 | /* | |
e6fb6da2 | 886 | * No more inodes for IO, bail |
71fd05a8 | 887 | */ |
b7a2441f | 888 | if (list_empty(&wb->b_more_io)) |
03ba3782 | 889 | break; |
71fd05a8 JA |
890 | /* |
891 | * Nothing written. Wait for some inode to | |
892 | * become available for writeback. Otherwise | |
893 | * we'll just busyloop. | |
894 | */ | |
71fd05a8 | 895 | if (!list_empty(&wb->b_more_io)) { |
d46db3d5 | 896 | trace_writeback_wait(wb->bdi, work); |
7ccf19a8 | 897 | inode = wb_inode(wb->b_more_io.prev); |
250df6ed | 898 | spin_lock(&inode->i_lock); |
f0d07b7f | 899 | spin_unlock(&wb->list_lock); |
169ebd90 JK |
900 | /* This function drops i_lock... */ |
901 | inode_sleep_on_writeback(inode); | |
f0d07b7f | 902 | spin_lock(&wb->list_lock); |
03ba3782 JA |
903 | } |
904 | } | |
e8dfc305 | 905 | spin_unlock(&wb->list_lock); |
03ba3782 | 906 | |
d46db3d5 | 907 | return nr_pages - work->nr_pages; |
03ba3782 JA |
908 | } |
909 | ||
910 | /* | |
83ba7b07 | 911 | * Return the next wb_writeback_work struct that hasn't been processed yet. |
03ba3782 | 912 | */ |
83ba7b07 | 913 | static struct wb_writeback_work * |
08852b6d | 914 | get_next_work_item(struct backing_dev_info *bdi) |
03ba3782 | 915 | { |
83ba7b07 | 916 | struct wb_writeback_work *work = NULL; |
03ba3782 | 917 | |
6467716a | 918 | spin_lock_bh(&bdi->wb_lock); |
83ba7b07 CH |
919 | if (!list_empty(&bdi->work_list)) { |
920 | work = list_entry(bdi->work_list.next, | |
921 | struct wb_writeback_work, list); | |
922 | list_del_init(&work->list); | |
03ba3782 | 923 | } |
6467716a | 924 | spin_unlock_bh(&bdi->wb_lock); |
83ba7b07 | 925 | return work; |
03ba3782 JA |
926 | } |
927 | ||
cdf01dd5 LT |
928 | /* |
929 | * Add in the number of potentially dirty inodes, because each inode | |
930 | * write can dirty pagecache in the underlying blockdev. | |
931 | */ | |
932 | static unsigned long get_nr_dirty_pages(void) | |
933 | { | |
934 | return global_page_state(NR_FILE_DIRTY) + | |
935 | global_page_state(NR_UNSTABLE_NFS) + | |
936 | get_nr_dirty_inodes(); | |
937 | } | |
938 | ||
6585027a JK |
939 | static long wb_check_background_flush(struct bdi_writeback *wb) |
940 | { | |
b00949aa | 941 | if (over_bground_thresh(wb->bdi)) { |
6585027a JK |
942 | |
943 | struct wb_writeback_work work = { | |
944 | .nr_pages = LONG_MAX, | |
945 | .sync_mode = WB_SYNC_NONE, | |
946 | .for_background = 1, | |
947 | .range_cyclic = 1, | |
0e175a18 | 948 | .reason = WB_REASON_BACKGROUND, |
6585027a JK |
949 | }; |
950 | ||
951 | return wb_writeback(wb, &work); | |
952 | } | |
953 | ||
954 | return 0; | |
955 | } | |
956 | ||
03ba3782 JA |
957 | static long wb_check_old_data_flush(struct bdi_writeback *wb) |
958 | { | |
959 | unsigned long expired; | |
960 | long nr_pages; | |
961 | ||
69b62d01 JA |
962 | /* |
963 | * When set to zero, disable periodic writeback | |
964 | */ | |
965 | if (!dirty_writeback_interval) | |
966 | return 0; | |
967 | ||
03ba3782 JA |
968 | expired = wb->last_old_flush + |
969 | msecs_to_jiffies(dirty_writeback_interval * 10); | |
970 | if (time_before(jiffies, expired)) | |
971 | return 0; | |
972 | ||
973 | wb->last_old_flush = jiffies; | |
cdf01dd5 | 974 | nr_pages = get_nr_dirty_pages(); |
03ba3782 | 975 | |
c4a77a6c | 976 | if (nr_pages) { |
83ba7b07 | 977 | struct wb_writeback_work work = { |
c4a77a6c JA |
978 | .nr_pages = nr_pages, |
979 | .sync_mode = WB_SYNC_NONE, | |
980 | .for_kupdate = 1, | |
981 | .range_cyclic = 1, | |
0e175a18 | 982 | .reason = WB_REASON_PERIODIC, |
c4a77a6c JA |
983 | }; |
984 | ||
83ba7b07 | 985 | return wb_writeback(wb, &work); |
c4a77a6c | 986 | } |
03ba3782 JA |
987 | |
988 | return 0; | |
989 | } | |
990 | ||
991 | /* | |
992 | * Retrieve work items and do the writeback they describe | |
993 | */ | |
994 | long wb_do_writeback(struct bdi_writeback *wb, int force_wait) | |
995 | { | |
996 | struct backing_dev_info *bdi = wb->bdi; | |
83ba7b07 | 997 | struct wb_writeback_work *work; |
c4a77a6c | 998 | long wrote = 0; |
03ba3782 | 999 | |
81d73a32 | 1000 | set_bit(BDI_writeback_running, &wb->bdi->state); |
08852b6d | 1001 | while ((work = get_next_work_item(bdi)) != NULL) { |
03ba3782 JA |
1002 | /* |
1003 | * Override sync mode, in case we must wait for completion | |
83ba7b07 | 1004 | * because this thread is exiting now. |
03ba3782 JA |
1005 | */ |
1006 | if (force_wait) | |
83ba7b07 | 1007 | work->sync_mode = WB_SYNC_ALL; |
03ba3782 | 1008 | |
455b2864 DC |
1009 | trace_writeback_exec(bdi, work); |
1010 | ||
83ba7b07 | 1011 | wrote += wb_writeback(wb, work); |
03ba3782 JA |
1012 | |
1013 | /* | |
83ba7b07 CH |
1014 | * Notify the caller of completion if this is a synchronous |
1015 | * work item, otherwise just free it. | |
03ba3782 | 1016 | */ |
83ba7b07 CH |
1017 | if (work->done) |
1018 | complete(work->done); | |
1019 | else | |
1020 | kfree(work); | |
03ba3782 JA |
1021 | } |
1022 | ||
1023 | /* | |
1024 | * Check for periodic writeback, kupdated() style | |
1025 | */ | |
1026 | wrote += wb_check_old_data_flush(wb); | |
6585027a | 1027 | wrote += wb_check_background_flush(wb); |
81d73a32 | 1028 | clear_bit(BDI_writeback_running, &wb->bdi->state); |
03ba3782 JA |
1029 | |
1030 | return wrote; | |
1031 | } | |
1032 | ||
1033 | /* | |
1034 | * Handle writeback of dirty data for the device backed by this bdi. Also | |
839a8e86 | 1035 | * reschedules periodically and does kupdated style flushing. |
03ba3782 | 1036 | */ |
839a8e86 | 1037 | void bdi_writeback_workfn(struct work_struct *work) |
03ba3782 | 1038 | { |
839a8e86 TH |
1039 | struct bdi_writeback *wb = container_of(to_delayed_work(work), |
1040 | struct bdi_writeback, dwork); | |
08243900 | 1041 | struct backing_dev_info *bdi = wb->bdi; |
03ba3782 JA |
1042 | long pages_written; |
1043 | ||
ef3b1019 | 1044 | set_worker_desc("flush-%s", dev_name(bdi->dev)); |
766f9164 | 1045 | current->flags |= PF_SWAPWRITE; |
455b2864 | 1046 | |
839a8e86 | 1047 | if (likely(!current_is_workqueue_rescuer() || |
bf097203 | 1048 | !test_bit(BDI_registered, &bdi->state))) { |
6467716a | 1049 | /* |
839a8e86 TH |
1050 | * The normal path. Keep writing back @bdi until its |
1051 | * work_list is empty. Note that this path is also taken | |
1052 | * if @bdi is shutting down even when we're running off the | |
1053 | * rescuer as work_list needs to be drained. | |
6467716a | 1054 | */ |
839a8e86 TH |
1055 | do { |
1056 | pages_written = wb_do_writeback(wb, 0); | |
1057 | trace_writeback_pages_written(pages_written); | |
1058 | } while (!list_empty(&bdi->work_list)); | |
1059 | } else { | |
1060 | /* | |
1061 | * bdi_wq can't get enough workers and we're running off | |
1062 | * the emergency worker. Don't hog it. Hopefully, 1024 is | |
1063 | * enough for efficient IO. | |
1064 | */ | |
1065 | pages_written = writeback_inodes_wb(&bdi->wb, 1024, | |
1066 | WB_REASON_FORKER_THREAD); | |
455b2864 | 1067 | trace_writeback_pages_written(pages_written); |
03ba3782 JA |
1068 | } |
1069 | ||
39305a6a DB |
1070 | if (!list_empty(&bdi->work_list)) |
1071 | mod_delayed_work(bdi_wq, &wb->dwork, 0); | |
1072 | else if (wb_has_dirty_io(wb) && dirty_writeback_interval) | |
1073 | bdi_wakeup_thread_delayed(bdi); | |
455b2864 | 1074 | |
839a8e86 | 1075 | current->flags &= ~PF_SWAPWRITE; |
03ba3782 JA |
1076 | } |
1077 | ||
1078 | /* | |
b8c2f347 CH |
1079 | * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back |
1080 | * the whole world. | |
03ba3782 | 1081 | */ |
0e175a18 | 1082 | void wakeup_flusher_threads(long nr_pages, enum wb_reason reason) |
03ba3782 | 1083 | { |
b8c2f347 | 1084 | struct backing_dev_info *bdi; |
03ba3782 | 1085 | |
83ba7b07 CH |
1086 | if (!nr_pages) { |
1087 | nr_pages = global_page_state(NR_FILE_DIRTY) + | |
b8c2f347 CH |
1088 | global_page_state(NR_UNSTABLE_NFS); |
1089 | } | |
03ba3782 | 1090 | |
b8c2f347 | 1091 | rcu_read_lock(); |
cfc4ba53 | 1092 | list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { |
03ba3782 JA |
1093 | if (!bdi_has_dirty_io(bdi)) |
1094 | continue; | |
0e175a18 | 1095 | __bdi_start_writeback(bdi, nr_pages, false, reason); |
03ba3782 | 1096 | } |
cfc4ba53 | 1097 | rcu_read_unlock(); |
1da177e4 LT |
1098 | } |
1099 | ||
03ba3782 JA |
1100 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
1101 | { | |
1102 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { | |
1103 | struct dentry *dentry; | |
1104 | const char *name = "?"; | |
1105 | ||
1106 | dentry = d_find_alias(inode); | |
1107 | if (dentry) { | |
1108 | spin_lock(&dentry->d_lock); | |
1109 | name = (const char *) dentry->d_name.name; | |
1110 | } | |
1111 | printk(KERN_DEBUG | |
1112 | "%s(%d): dirtied inode %lu (%s) on %s\n", | |
1113 | current->comm, task_pid_nr(current), inode->i_ino, | |
1114 | name, inode->i_sb->s_id); | |
1115 | if (dentry) { | |
1116 | spin_unlock(&dentry->d_lock); | |
1117 | dput(dentry); | |
1118 | } | |
1119 | } | |
1120 | } | |
1121 | ||
1122 | /** | |
1123 | * __mark_inode_dirty - internal function | |
1124 | * @inode: inode to mark | |
1125 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) | |
1126 | * Mark an inode as dirty. Callers should use mark_inode_dirty or | |
1127 | * mark_inode_dirty_sync. | |
1da177e4 | 1128 | * |
03ba3782 JA |
1129 | * Put the inode on the super block's dirty list. |
1130 | * | |
1131 | * CAREFUL! We mark it dirty unconditionally, but move it onto the | |
1132 | * dirty list only if it is hashed or if it refers to a blockdev. | |
1133 | * If it was not hashed, it will never be added to the dirty list | |
1134 | * even if it is later hashed, as it will have been marked dirty already. | |
1135 | * | |
1136 | * In short, make sure you hash any inodes _before_ you start marking | |
1137 | * them dirty. | |
1da177e4 | 1138 | * |
03ba3782 JA |
1139 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of |
1140 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of | |
1141 | * the kernel-internal blockdev inode represents the dirtying time of the | |
1142 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use | |
1143 | * page->mapping->host, so the page-dirtying time is recorded in the internal | |
1144 | * blockdev inode. | |
1da177e4 | 1145 | */ |
03ba3782 | 1146 | void __mark_inode_dirty(struct inode *inode, int flags) |
1da177e4 | 1147 | { |
03ba3782 | 1148 | struct super_block *sb = inode->i_sb; |
253c34e9 | 1149 | struct backing_dev_info *bdi = NULL; |
1da177e4 | 1150 | |
03ba3782 JA |
1151 | /* |
1152 | * Don't do this for I_DIRTY_PAGES - that doesn't actually | |
1153 | * dirty the inode itself | |
1154 | */ | |
1155 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
9fb0a7da TH |
1156 | trace_writeback_dirty_inode_start(inode, flags); |
1157 | ||
03ba3782 | 1158 | if (sb->s_op->dirty_inode) |
aa385729 | 1159 | sb->s_op->dirty_inode(inode, flags); |
9fb0a7da TH |
1160 | |
1161 | trace_writeback_dirty_inode(inode, flags); | |
03ba3782 JA |
1162 | } |
1163 | ||
1164 | /* | |
21fe2674 TH |
1165 | * Paired with smp_mb() in __writeback_single_inode() for the |
1166 | * following lockless i_state test. See there for details. | |
03ba3782 JA |
1167 | */ |
1168 | smp_mb(); | |
1169 | ||
03ba3782 JA |
1170 | if ((inode->i_state & flags) == flags) |
1171 | return; | |
1172 | ||
6fa3eb70 | 1173 | if (unlikely(block_dump > 1)) |
03ba3782 JA |
1174 | block_dump___mark_inode_dirty(inode); |
1175 | ||
250df6ed | 1176 | spin_lock(&inode->i_lock); |
03ba3782 JA |
1177 | if ((inode->i_state & flags) != flags) { |
1178 | const int was_dirty = inode->i_state & I_DIRTY; | |
1179 | ||
1180 | inode->i_state |= flags; | |
1181 | ||
1182 | /* | |
1183 | * If the inode is being synced, just update its dirty state. | |
1184 | * The unlocker will place the inode on the appropriate | |
1185 | * superblock list, based upon its state. | |
1186 | */ | |
1187 | if (inode->i_state & I_SYNC) | |
250df6ed | 1188 | goto out_unlock_inode; |
03ba3782 JA |
1189 | |
1190 | /* | |
1191 | * Only add valid (hashed) inodes to the superblock's | |
1192 | * dirty list. Add blockdev inodes as well. | |
1193 | */ | |
1194 | if (!S_ISBLK(inode->i_mode)) { | |
1d3382cb | 1195 | if (inode_unhashed(inode)) |
250df6ed | 1196 | goto out_unlock_inode; |
03ba3782 | 1197 | } |
a4ffdde6 | 1198 | if (inode->i_state & I_FREEING) |
250df6ed | 1199 | goto out_unlock_inode; |
03ba3782 JA |
1200 | |
1201 | /* | |
1202 | * If the inode was already on b_dirty/b_io/b_more_io, don't | |
1203 | * reposition it (that would break b_dirty time-ordering). | |
1204 | */ | |
1205 | if (!was_dirty) { | |
a66979ab | 1206 | bool wakeup_bdi = false; |
253c34e9 AB |
1207 | bdi = inode_to_bdi(inode); |
1208 | ||
1209 | if (bdi_cap_writeback_dirty(bdi)) { | |
1210 | WARN(!test_bit(BDI_registered, &bdi->state), | |
1211 | "bdi-%s not registered\n", bdi->name); | |
1212 | ||
1213 | /* | |
1214 | * If this is the first dirty inode for this | |
1215 | * bdi, we have to wake-up the corresponding | |
1216 | * bdi thread to make sure background | |
1217 | * write-back happens later. | |
1218 | */ | |
1219 | if (!wb_has_dirty_io(&bdi->wb)) | |
1220 | wakeup_bdi = true; | |
500b067c | 1221 | } |
03ba3782 | 1222 | |
a66979ab | 1223 | spin_unlock(&inode->i_lock); |
f758eeab | 1224 | spin_lock(&bdi->wb.list_lock); |
03ba3782 | 1225 | inode->dirtied_when = jiffies; |
7ccf19a8 | 1226 | list_move(&inode->i_wb_list, &bdi->wb.b_dirty); |
f758eeab | 1227 | spin_unlock(&bdi->wb.list_lock); |
a66979ab DC |
1228 | |
1229 | if (wakeup_bdi) | |
1230 | bdi_wakeup_thread_delayed(bdi); | |
1231 | return; | |
1da177e4 | 1232 | } |
1da177e4 | 1233 | } |
250df6ed DC |
1234 | out_unlock_inode: |
1235 | spin_unlock(&inode->i_lock); | |
253c34e9 | 1236 | |
03ba3782 JA |
1237 | } |
1238 | EXPORT_SYMBOL(__mark_inode_dirty); | |
1239 | ||
b6e51316 | 1240 | static void wait_sb_inodes(struct super_block *sb) |
03ba3782 JA |
1241 | { |
1242 | struct inode *inode, *old_inode = NULL; | |
1243 | ||
1244 | /* | |
1245 | * We need to be protected against the filesystem going from | |
1246 | * r/o to r/w or vice versa. | |
1247 | */ | |
b6e51316 | 1248 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
03ba3782 | 1249 | |
55fa6091 | 1250 | spin_lock(&inode_sb_list_lock); |
03ba3782 JA |
1251 | |
1252 | /* | |
1253 | * Data integrity sync. Must wait for all pages under writeback, | |
1254 | * because there may have been pages dirtied before our sync | |
1255 | * call, but which had writeout started before we write it out. | |
1256 | * In which case, the inode may not be on the dirty list, but | |
1257 | * we still have to wait for that writeout. | |
1258 | */ | |
b6e51316 | 1259 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
250df6ed | 1260 | struct address_space *mapping = inode->i_mapping; |
03ba3782 | 1261 | |
250df6ed DC |
1262 | spin_lock(&inode->i_lock); |
1263 | if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) || | |
1264 | (mapping->nrpages == 0)) { | |
1265 | spin_unlock(&inode->i_lock); | |
03ba3782 | 1266 | continue; |
250df6ed | 1267 | } |
03ba3782 | 1268 | __iget(inode); |
250df6ed | 1269 | spin_unlock(&inode->i_lock); |
55fa6091 DC |
1270 | spin_unlock(&inode_sb_list_lock); |
1271 | ||
03ba3782 | 1272 | /* |
55fa6091 DC |
1273 | * We hold a reference to 'inode' so it couldn't have been |
1274 | * removed from s_inodes list while we dropped the | |
1275 | * inode_sb_list_lock. We cannot iput the inode now as we can | |
1276 | * be holding the last reference and we cannot iput it under | |
1277 | * inode_sb_list_lock. So we keep the reference and iput it | |
1278 | * later. | |
03ba3782 JA |
1279 | */ |
1280 | iput(old_inode); | |
1281 | old_inode = inode; | |
1282 | ||
1283 | filemap_fdatawait(mapping); | |
1284 | ||
1285 | cond_resched(); | |
1286 | ||
55fa6091 | 1287 | spin_lock(&inode_sb_list_lock); |
03ba3782 | 1288 | } |
55fa6091 | 1289 | spin_unlock(&inode_sb_list_lock); |
03ba3782 | 1290 | iput(old_inode); |
1da177e4 LT |
1291 | } |
1292 | ||
d8a8559c | 1293 | /** |
3259f8be | 1294 | * writeback_inodes_sb_nr - writeback dirty inodes from given super_block |
d8a8559c | 1295 | * @sb: the superblock |
3259f8be | 1296 | * @nr: the number of pages to write |
786228ab | 1297 | * @reason: reason why some writeback work initiated |
1da177e4 | 1298 | * |
d8a8559c JA |
1299 | * Start writeback on some inodes on this super_block. No guarantees are made |
1300 | * on how many (if any) will be written, and this function does not wait | |
3259f8be | 1301 | * for IO completion of submitted IO. |
1da177e4 | 1302 | */ |
0e175a18 CW |
1303 | void writeback_inodes_sb_nr(struct super_block *sb, |
1304 | unsigned long nr, | |
1305 | enum wb_reason reason) | |
1da177e4 | 1306 | { |
83ba7b07 CH |
1307 | DECLARE_COMPLETION_ONSTACK(done); |
1308 | struct wb_writeback_work work = { | |
6e6938b6 WF |
1309 | .sb = sb, |
1310 | .sync_mode = WB_SYNC_NONE, | |
1311 | .tagged_writepages = 1, | |
1312 | .done = &done, | |
1313 | .nr_pages = nr, | |
0e175a18 | 1314 | .reason = reason, |
3c4d7165 | 1315 | }; |
d8a8559c | 1316 | |
6eedc701 JK |
1317 | if (sb->s_bdi == &noop_backing_dev_info) |
1318 | return; | |
cf37e972 | 1319 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); |
83ba7b07 CH |
1320 | bdi_queue_work(sb->s_bdi, &work); |
1321 | wait_for_completion(&done); | |
e913fc82 | 1322 | } |
3259f8be CM |
1323 | EXPORT_SYMBOL(writeback_inodes_sb_nr); |
1324 | ||
1325 | /** | |
1326 | * writeback_inodes_sb - writeback dirty inodes from given super_block | |
1327 | * @sb: the superblock | |
786228ab | 1328 | * @reason: reason why some writeback work was initiated |
3259f8be CM |
1329 | * |
1330 | * Start writeback on some inodes on this super_block. No guarantees are made | |
1331 | * on how many (if any) will be written, and this function does not wait | |
1332 | * for IO completion of submitted IO. | |
1333 | */ | |
0e175a18 | 1334 | void writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
3259f8be | 1335 | { |
0e175a18 | 1336 | return writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
3259f8be | 1337 | } |
0e3c9a22 | 1338 | EXPORT_SYMBOL(writeback_inodes_sb); |
e913fc82 | 1339 | |
17bd55d0 | 1340 | /** |
10ee27a0 | 1341 | * try_to_writeback_inodes_sb_nr - try to start writeback if none underway |
17bd55d0 | 1342 | * @sb: the superblock |
10ee27a0 MX |
1343 | * @nr: the number of pages to write |
1344 | * @reason: the reason of writeback | |
17bd55d0 | 1345 | * |
10ee27a0 | 1346 | * Invoke writeback_inodes_sb_nr if no writeback is currently underway. |
17bd55d0 ES |
1347 | * Returns 1 if writeback was started, 0 if not. |
1348 | */ | |
10ee27a0 MX |
1349 | int try_to_writeback_inodes_sb_nr(struct super_block *sb, |
1350 | unsigned long nr, | |
1351 | enum wb_reason reason) | |
17bd55d0 | 1352 | { |
10ee27a0 | 1353 | if (writeback_in_progress(sb->s_bdi)) |
17bd55d0 | 1354 | return 1; |
10ee27a0 MX |
1355 | |
1356 | if (!down_read_trylock(&sb->s_umount)) | |
17bd55d0 | 1357 | return 0; |
10ee27a0 MX |
1358 | |
1359 | writeback_inodes_sb_nr(sb, nr, reason); | |
1360 | up_read(&sb->s_umount); | |
1361 | return 1; | |
17bd55d0 | 1362 | } |
10ee27a0 | 1363 | EXPORT_SYMBOL(try_to_writeback_inodes_sb_nr); |
17bd55d0 | 1364 | |
3259f8be | 1365 | /** |
10ee27a0 | 1366 | * try_to_writeback_inodes_sb - try to start writeback if none underway |
3259f8be | 1367 | * @sb: the superblock |
786228ab | 1368 | * @reason: reason why some writeback work was initiated |
3259f8be | 1369 | * |
10ee27a0 | 1370 | * Implement by try_to_writeback_inodes_sb_nr() |
3259f8be CM |
1371 | * Returns 1 if writeback was started, 0 if not. |
1372 | */ | |
10ee27a0 | 1373 | int try_to_writeback_inodes_sb(struct super_block *sb, enum wb_reason reason) |
3259f8be | 1374 | { |
10ee27a0 | 1375 | return try_to_writeback_inodes_sb_nr(sb, get_nr_dirty_pages(), reason); |
3259f8be | 1376 | } |
10ee27a0 | 1377 | EXPORT_SYMBOL(try_to_writeback_inodes_sb); |
3259f8be | 1378 | |
d8a8559c JA |
1379 | /** |
1380 | * sync_inodes_sb - sync sb inode pages | |
1381 | * @sb: the superblock | |
1382 | * | |
1383 | * This function writes and waits on any dirty inode belonging to this | |
cb9ef8d5 | 1384 | * super_block. |
d8a8559c | 1385 | */ |
b6e51316 | 1386 | void sync_inodes_sb(struct super_block *sb) |
d8a8559c | 1387 | { |
83ba7b07 CH |
1388 | DECLARE_COMPLETION_ONSTACK(done); |
1389 | struct wb_writeback_work work = { | |
3c4d7165 CH |
1390 | .sb = sb, |
1391 | .sync_mode = WB_SYNC_ALL, | |
1392 | .nr_pages = LONG_MAX, | |
1393 | .range_cyclic = 0, | |
83ba7b07 | 1394 | .done = &done, |
0e175a18 | 1395 | .reason = WB_REASON_SYNC, |
3c4d7165 CH |
1396 | }; |
1397 | ||
6eedc701 JK |
1398 | /* Nothing to do? */ |
1399 | if (sb->s_bdi == &noop_backing_dev_info) | |
1400 | return; | |
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); |