Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * fs/fs-writeback.c | |
3 | * | |
4 | * Copyright (C) 2002, Linus Torvalds. | |
5 | * | |
6 | * Contains all the functions related to writing back and waiting | |
7 | * upon dirty inodes against superblocks, and writing back dirty | |
8 | * pages against inodes. ie: data writeback. Writeout of the | |
9 | * inode itself is not handled here. | |
10 | * | |
e1f8e874 | 11 | * 10Apr2002 Andrew Morton |
1da177e4 LT |
12 | * Split out of fs/inode.c |
13 | * Additions for address_space-based writeback | |
14 | */ | |
15 | ||
16 | #include <linux/kernel.h> | |
f5ff8422 | 17 | #include <linux/module.h> |
1da177e4 LT |
18 | #include <linux/spinlock.h> |
19 | #include <linux/sched.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/mm.h> | |
22 | #include <linux/writeback.h> | |
23 | #include <linux/blkdev.h> | |
24 | #include <linux/backing-dev.h> | |
25 | #include <linux/buffer_head.h> | |
07f3f05c | 26 | #include "internal.h" |
1da177e4 | 27 | |
f11b00f3 AB |
28 | |
29 | /** | |
30 | * writeback_acquire - attempt to get exclusive writeback access to a device | |
31 | * @bdi: the device's backing_dev_info structure | |
32 | * | |
33 | * It is a waste of resources to have more than one pdflush thread blocked on | |
34 | * a single request queue. Exclusion at the request_queue level is obtained | |
35 | * via a flag in the request_queue's backing_dev_info.state. | |
36 | * | |
37 | * Non-request_queue-backed address_spaces will share default_backing_dev_info, | |
38 | * unless they implement their own. Which is somewhat inefficient, as this | |
39 | * may prevent concurrent writeback against multiple devices. | |
40 | */ | |
41 | static int writeback_acquire(struct backing_dev_info *bdi) | |
42 | { | |
43 | return !test_and_set_bit(BDI_pdflush, &bdi->state); | |
44 | } | |
45 | ||
46 | /** | |
47 | * writeback_in_progress - determine whether there is writeback in progress | |
48 | * @bdi: the device's backing_dev_info structure. | |
49 | * | |
50 | * Determine whether there is writeback in progress against a backing device. | |
51 | */ | |
52 | int writeback_in_progress(struct backing_dev_info *bdi) | |
53 | { | |
54 | return test_bit(BDI_pdflush, &bdi->state); | |
55 | } | |
56 | ||
57 | /** | |
58 | * writeback_release - relinquish exclusive writeback access against a device. | |
59 | * @bdi: the device's backing_dev_info structure | |
60 | */ | |
61 | static void writeback_release(struct backing_dev_info *bdi) | |
62 | { | |
63 | BUG_ON(!writeback_in_progress(bdi)); | |
64 | clear_bit(BDI_pdflush, &bdi->state); | |
65 | } | |
66 | ||
4195f73d NP |
67 | static noinline void block_dump___mark_inode_dirty(struct inode *inode) |
68 | { | |
69 | if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { | |
70 | struct dentry *dentry; | |
71 | const char *name = "?"; | |
72 | ||
73 | dentry = d_find_alias(inode); | |
74 | if (dentry) { | |
75 | spin_lock(&dentry->d_lock); | |
76 | name = (const char *) dentry->d_name.name; | |
77 | } | |
78 | printk(KERN_DEBUG | |
79 | "%s(%d): dirtied inode %lu (%s) on %s\n", | |
80 | current->comm, task_pid_nr(current), inode->i_ino, | |
81 | name, inode->i_sb->s_id); | |
82 | if (dentry) { | |
83 | spin_unlock(&dentry->d_lock); | |
84 | dput(dentry); | |
85 | } | |
86 | } | |
87 | } | |
88 | ||
1da177e4 LT |
89 | /** |
90 | * __mark_inode_dirty - internal function | |
91 | * @inode: inode to mark | |
92 | * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) | |
93 | * Mark an inode as dirty. Callers should use mark_inode_dirty or | |
94 | * mark_inode_dirty_sync. | |
95 | * | |
96 | * Put the inode on the super block's dirty list. | |
97 | * | |
98 | * CAREFUL! We mark it dirty unconditionally, but move it onto the | |
99 | * dirty list only if it is hashed or if it refers to a blockdev. | |
100 | * If it was not hashed, it will never be added to the dirty list | |
101 | * even if it is later hashed, as it will have been marked dirty already. | |
102 | * | |
103 | * In short, make sure you hash any inodes _before_ you start marking | |
104 | * them dirty. | |
105 | * | |
106 | * This function *must* be atomic for the I_DIRTY_PAGES case - | |
107 | * set_page_dirty() is called under spinlock in several places. | |
108 | * | |
109 | * Note that for blockdevs, inode->dirtied_when represents the dirtying time of | |
110 | * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of | |
111 | * the kernel-internal blockdev inode represents the dirtying time of the | |
112 | * blockdev's pages. This is why for I_DIRTY_PAGES we always use | |
113 | * page->mapping->host, so the page-dirtying time is recorded in the internal | |
114 | * blockdev inode. | |
115 | */ | |
116 | void __mark_inode_dirty(struct inode *inode, int flags) | |
117 | { | |
118 | struct super_block *sb = inode->i_sb; | |
119 | ||
120 | /* | |
121 | * Don't do this for I_DIRTY_PAGES - that doesn't actually | |
122 | * dirty the inode itself | |
123 | */ | |
124 | if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
125 | if (sb->s_op->dirty_inode) | |
126 | sb->s_op->dirty_inode(inode); | |
127 | } | |
128 | ||
129 | /* | |
130 | * make sure that changes are seen by all cpus before we test i_state | |
131 | * -- mikulas | |
132 | */ | |
133 | smp_mb(); | |
134 | ||
135 | /* avoid the locking if we can */ | |
136 | if ((inode->i_state & flags) == flags) | |
137 | return; | |
138 | ||
4195f73d NP |
139 | if (unlikely(block_dump)) |
140 | block_dump___mark_inode_dirty(inode); | |
1da177e4 LT |
141 | |
142 | spin_lock(&inode_lock); | |
143 | if ((inode->i_state & flags) != flags) { | |
144 | const int was_dirty = inode->i_state & I_DIRTY; | |
145 | ||
146 | inode->i_state |= flags; | |
147 | ||
148 | /* | |
1c0eeaf5 | 149 | * If the inode is being synced, just update its dirty state. |
1da177e4 LT |
150 | * The unlocker will place the inode on the appropriate |
151 | * superblock list, based upon its state. | |
152 | */ | |
1c0eeaf5 | 153 | if (inode->i_state & I_SYNC) |
1da177e4 LT |
154 | goto out; |
155 | ||
156 | /* | |
157 | * Only add valid (hashed) inodes to the superblock's | |
158 | * dirty list. Add blockdev inodes as well. | |
159 | */ | |
160 | if (!S_ISBLK(inode->i_mode)) { | |
161 | if (hlist_unhashed(&inode->i_hash)) | |
162 | goto out; | |
163 | } | |
164 | if (inode->i_state & (I_FREEING|I_CLEAR)) | |
165 | goto out; | |
166 | ||
167 | /* | |
2c136579 | 168 | * If the inode was already on s_dirty/s_io/s_more_io, don't |
1da177e4 LT |
169 | * reposition it (that would break s_dirty time-ordering). |
170 | */ | |
171 | if (!was_dirty) { | |
172 | inode->dirtied_when = jiffies; | |
173 | list_move(&inode->i_list, &sb->s_dirty); | |
174 | } | |
175 | } | |
176 | out: | |
177 | spin_unlock(&inode_lock); | |
178 | } | |
179 | ||
180 | EXPORT_SYMBOL(__mark_inode_dirty); | |
181 | ||
182 | static int write_inode(struct inode *inode, int sync) | |
183 | { | |
184 | if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) | |
185 | return inode->i_sb->s_op->write_inode(inode, sync); | |
186 | return 0; | |
187 | } | |
188 | ||
6610a0bc AM |
189 | /* |
190 | * Redirty an inode: set its when-it-was dirtied timestamp and move it to the | |
191 | * furthest end of its superblock's dirty-inode list. | |
192 | * | |
193 | * Before stamping the inode's ->dirtied_when, we check to see whether it is | |
194 | * already the most-recently-dirtied inode on the s_dirty list. If that is | |
195 | * the case then the inode must have been redirtied while it was being written | |
196 | * out and we don't reset its dirtied_when. | |
197 | */ | |
198 | static void redirty_tail(struct inode *inode) | |
199 | { | |
200 | struct super_block *sb = inode->i_sb; | |
201 | ||
202 | if (!list_empty(&sb->s_dirty)) { | |
203 | struct inode *tail_inode; | |
204 | ||
205 | tail_inode = list_entry(sb->s_dirty.next, struct inode, i_list); | |
d2caa3c5 | 206 | if (time_before(inode->dirtied_when, |
6610a0bc AM |
207 | tail_inode->dirtied_when)) |
208 | inode->dirtied_when = jiffies; | |
209 | } | |
210 | list_move(&inode->i_list, &sb->s_dirty); | |
211 | } | |
212 | ||
c986d1e2 | 213 | /* |
0e0f4fc2 | 214 | * requeue inode for re-scanning after sb->s_io list is exhausted. |
c986d1e2 | 215 | */ |
0e0f4fc2 | 216 | static void requeue_io(struct inode *inode) |
c986d1e2 | 217 | { |
0e0f4fc2 | 218 | list_move(&inode->i_list, &inode->i_sb->s_more_io); |
c986d1e2 AM |
219 | } |
220 | ||
1c0eeaf5 JE |
221 | static void inode_sync_complete(struct inode *inode) |
222 | { | |
223 | /* | |
224 | * Prevent speculative execution through spin_unlock(&inode_lock); | |
225 | */ | |
226 | smp_mb(); | |
227 | wake_up_bit(&inode->i_state, __I_SYNC); | |
228 | } | |
229 | ||
d2caa3c5 JL |
230 | static bool inode_dirtied_after(struct inode *inode, unsigned long t) |
231 | { | |
232 | bool ret = time_after(inode->dirtied_when, t); | |
233 | #ifndef CONFIG_64BIT | |
234 | /* | |
235 | * For inodes being constantly redirtied, dirtied_when can get stuck. | |
236 | * It _appears_ to be in the future, but is actually in distant past. | |
237 | * This test is necessary to prevent such wrapped-around relative times | |
238 | * from permanently stopping the whole pdflush writeback. | |
239 | */ | |
240 | ret = ret && time_before_eq(inode->dirtied_when, jiffies); | |
241 | #endif | |
242 | return ret; | |
243 | } | |
244 | ||
2c136579 FW |
245 | /* |
246 | * Move expired dirty inodes from @delaying_queue to @dispatch_queue. | |
247 | */ | |
248 | static void move_expired_inodes(struct list_head *delaying_queue, | |
249 | struct list_head *dispatch_queue, | |
250 | unsigned long *older_than_this) | |
251 | { | |
252 | while (!list_empty(delaying_queue)) { | |
253 | struct inode *inode = list_entry(delaying_queue->prev, | |
254 | struct inode, i_list); | |
255 | if (older_than_this && | |
d2caa3c5 | 256 | inode_dirtied_after(inode, *older_than_this)) |
2c136579 FW |
257 | break; |
258 | list_move(&inode->i_list, dispatch_queue); | |
259 | } | |
260 | } | |
261 | ||
262 | /* | |
263 | * Queue all expired dirty inodes for io, eldest first. | |
264 | */ | |
265 | static void queue_io(struct super_block *sb, | |
266 | unsigned long *older_than_this) | |
267 | { | |
268 | list_splice_init(&sb->s_more_io, sb->s_io.prev); | |
269 | move_expired_inodes(&sb->s_dirty, &sb->s_io, older_than_this); | |
270 | } | |
271 | ||
08d8e974 FW |
272 | int sb_has_dirty_inodes(struct super_block *sb) |
273 | { | |
274 | return !list_empty(&sb->s_dirty) || | |
275 | !list_empty(&sb->s_io) || | |
276 | !list_empty(&sb->s_more_io); | |
277 | } | |
278 | EXPORT_SYMBOL(sb_has_dirty_inodes); | |
279 | ||
1da177e4 LT |
280 | /* |
281 | * Write a single inode's dirty pages and inode data out to disk. | |
282 | * If `wait' is set, wait on the writeout. | |
283 | * | |
284 | * The whole writeout design is quite complex and fragile. We want to avoid | |
285 | * starvation of particular inodes when others are being redirtied, prevent | |
286 | * livelocks, etc. | |
287 | * | |
288 | * Called under inode_lock. | |
289 | */ | |
290 | static int | |
291 | __sync_single_inode(struct inode *inode, struct writeback_control *wbc) | |
292 | { | |
293 | unsigned dirty; | |
294 | struct address_space *mapping = inode->i_mapping; | |
1da177e4 LT |
295 | int wait = wbc->sync_mode == WB_SYNC_ALL; |
296 | int ret; | |
297 | ||
1c0eeaf5 | 298 | BUG_ON(inode->i_state & I_SYNC); |
1da177e4 | 299 | |
1c0eeaf5 | 300 | /* Set I_SYNC, reset I_DIRTY */ |
1da177e4 | 301 | dirty = inode->i_state & I_DIRTY; |
1c0eeaf5 | 302 | inode->i_state |= I_SYNC; |
1da177e4 LT |
303 | inode->i_state &= ~I_DIRTY; |
304 | ||
305 | spin_unlock(&inode_lock); | |
306 | ||
307 | ret = do_writepages(mapping, wbc); | |
308 | ||
309 | /* Don't write the inode if only I_DIRTY_PAGES was set */ | |
310 | if (dirty & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { | |
311 | int err = write_inode(inode, wait); | |
312 | if (ret == 0) | |
313 | ret = err; | |
314 | } | |
315 | ||
316 | if (wait) { | |
317 | int err = filemap_fdatawait(mapping); | |
318 | if (ret == 0) | |
319 | ret = err; | |
320 | } | |
321 | ||
322 | spin_lock(&inode_lock); | |
1c0eeaf5 | 323 | inode->i_state &= ~I_SYNC; |
84a89245 | 324 | if (!(inode->i_state & (I_FREEING | I_CLEAR))) { |
1da177e4 LT |
325 | if (!(inode->i_state & I_DIRTY) && |
326 | mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { | |
327 | /* | |
328 | * We didn't write back all the pages. nfs_writepages() | |
329 | * sometimes bales out without doing anything. Redirty | |
2c136579 | 330 | * the inode; Move it from s_io onto s_more_io/s_dirty. |
1b43ef91 AM |
331 | */ |
332 | /* | |
333 | * akpm: if the caller was the kupdate function we put | |
334 | * this inode at the head of s_dirty so it gets first | |
335 | * consideration. Otherwise, move it to the tail, for | |
336 | * the reasons described there. I'm not really sure | |
337 | * how much sense this makes. Presumably I had a good | |
338 | * reasons for doing it this way, and I'd rather not | |
339 | * muck with it at present. | |
1da177e4 LT |
340 | */ |
341 | if (wbc->for_kupdate) { | |
342 | /* | |
2c136579 FW |
343 | * For the kupdate function we move the inode |
344 | * to s_more_io so it will get more writeout as | |
345 | * soon as the queue becomes uncongested. | |
1da177e4 LT |
346 | */ |
347 | inode->i_state |= I_DIRTY_PAGES; | |
8bc3be27 FW |
348 | if (wbc->nr_to_write <= 0) { |
349 | /* | |
350 | * slice used up: queue for next turn | |
351 | */ | |
352 | requeue_io(inode); | |
353 | } else { | |
354 | /* | |
355 | * somehow blocked: retry later | |
356 | */ | |
357 | redirty_tail(inode); | |
358 | } | |
1da177e4 LT |
359 | } else { |
360 | /* | |
361 | * Otherwise fully redirty the inode so that | |
362 | * other inodes on this superblock will get some | |
363 | * writeout. Otherwise heavy writing to one | |
364 | * file would indefinitely suspend writeout of | |
365 | * all the other files. | |
366 | */ | |
367 | inode->i_state |= I_DIRTY_PAGES; | |
1b43ef91 | 368 | redirty_tail(inode); |
1da177e4 LT |
369 | } |
370 | } else if (inode->i_state & I_DIRTY) { | |
371 | /* | |
372 | * Someone redirtied the inode while were writing back | |
373 | * the pages. | |
374 | */ | |
6610a0bc | 375 | redirty_tail(inode); |
1da177e4 LT |
376 | } else if (atomic_read(&inode->i_count)) { |
377 | /* | |
378 | * The inode is clean, inuse | |
379 | */ | |
380 | list_move(&inode->i_list, &inode_in_use); | |
381 | } else { | |
382 | /* | |
383 | * The inode is clean, unused | |
384 | */ | |
385 | list_move(&inode->i_list, &inode_unused); | |
1da177e4 LT |
386 | } |
387 | } | |
1c0eeaf5 | 388 | inode_sync_complete(inode); |
1da177e4 LT |
389 | return ret; |
390 | } | |
391 | ||
392 | /* | |
7f04c26d AA |
393 | * Write out an inode's dirty pages. Called under inode_lock. Either the |
394 | * caller has ref on the inode (either via __iget or via syscall against an fd) | |
395 | * or the inode has I_WILL_FREE set (via generic_forget_inode) | |
1da177e4 LT |
396 | */ |
397 | static int | |
7f04c26d | 398 | __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) |
1da177e4 LT |
399 | { |
400 | wait_queue_head_t *wqh; | |
401 | ||
7f04c26d | 402 | if (!atomic_read(&inode->i_count)) |
659603ef | 403 | WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); |
7f04c26d AA |
404 | else |
405 | WARN_ON(inode->i_state & I_WILL_FREE); | |
406 | ||
1c0eeaf5 | 407 | if ((wbc->sync_mode != WB_SYNC_ALL) && (inode->i_state & I_SYNC)) { |
65cb9b47 AM |
408 | /* |
409 | * We're skipping this inode because it's locked, and we're not | |
2c136579 FW |
410 | * doing writeback-for-data-integrity. Move it to s_more_io so |
411 | * that writeback can proceed with the other inodes on s_io. | |
412 | * We'll have another go at writing back this inode when we | |
413 | * completed a full scan of s_io. | |
65cb9b47 | 414 | */ |
0e0f4fc2 | 415 | requeue_io(inode); |
2d544564 | 416 | return 0; |
1da177e4 LT |
417 | } |
418 | ||
419 | /* | |
420 | * It's a data-integrity sync. We must wait. | |
421 | */ | |
1c0eeaf5 JE |
422 | if (inode->i_state & I_SYNC) { |
423 | DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); | |
1da177e4 | 424 | |
1c0eeaf5 | 425 | wqh = bit_waitqueue(&inode->i_state, __I_SYNC); |
1da177e4 | 426 | do { |
1da177e4 LT |
427 | spin_unlock(&inode_lock); |
428 | __wait_on_bit(wqh, &wq, inode_wait, | |
429 | TASK_UNINTERRUPTIBLE); | |
1da177e4 | 430 | spin_lock(&inode_lock); |
1c0eeaf5 | 431 | } while (inode->i_state & I_SYNC); |
1da177e4 LT |
432 | } |
433 | return __sync_single_inode(inode, wbc); | |
434 | } | |
435 | ||
436 | /* | |
437 | * Write out a superblock's list of dirty inodes. A wait will be performed | |
438 | * upon no inodes, all inodes or the final one, depending upon sync_mode. | |
439 | * | |
440 | * If older_than_this is non-NULL, then only write out inodes which | |
441 | * had their first dirtying at a time earlier than *older_than_this. | |
442 | * | |
3e3cb64f | 443 | * If we're a pdflush thread, then implement pdflush collision avoidance |
1da177e4 LT |
444 | * against the entire list. |
445 | * | |
1da177e4 LT |
446 | * If `bdi' is non-zero then we're being asked to writeback a specific queue. |
447 | * This function assumes that the blockdev superblock's inodes are backed by | |
448 | * a variety of queues, so all inodes are searched. For other superblocks, | |
449 | * assume that all inodes are backed by the same queue. | |
450 | * | |
451 | * FIXME: this linear search could get expensive with many fileystems. But | |
452 | * how to fix? We need to go from an address_space to all inodes which share | |
453 | * a queue with that address_space. (Easy: have a global "dirty superblocks" | |
454 | * list). | |
455 | * | |
456 | * The inodes to be written are parked on sb->s_io. They are moved back onto | |
457 | * sb->s_dirty as they are selected for writing. This way, none can be missed | |
458 | * on the writer throttling path, and we get decent balancing between many | |
1c0eeaf5 | 459 | * throttled threads: we don't want them all piling up on inode_sync_wait. |
1da177e4 | 460 | */ |
4ee6afd3 AB |
461 | void generic_sync_sb_inodes(struct super_block *sb, |
462 | struct writeback_control *wbc) | |
1da177e4 LT |
463 | { |
464 | const unsigned long start = jiffies; /* livelock avoidance */ | |
38f21977 | 465 | int sync = wbc->sync_mode == WB_SYNC_ALL; |
1da177e4 | 466 | |
ae8547b0 | 467 | spin_lock(&inode_lock); |
1da177e4 | 468 | if (!wbc->for_kupdate || list_empty(&sb->s_io)) |
2c136579 | 469 | queue_io(sb, wbc->older_than_this); |
1da177e4 LT |
470 | |
471 | while (!list_empty(&sb->s_io)) { | |
472 | struct inode *inode = list_entry(sb->s_io.prev, | |
473 | struct inode, i_list); | |
474 | struct address_space *mapping = inode->i_mapping; | |
475 | struct backing_dev_info *bdi = mapping->backing_dev_info; | |
476 | long pages_skipped; | |
477 | ||
478 | if (!bdi_cap_writeback_dirty(bdi)) { | |
9852a0e7 | 479 | redirty_tail(inode); |
7b0de42d | 480 | if (sb_is_blkdev_sb(sb)) { |
1da177e4 LT |
481 | /* |
482 | * Dirty memory-backed blockdev: the ramdisk | |
483 | * driver does this. Skip just this inode | |
484 | */ | |
485 | continue; | |
486 | } | |
487 | /* | |
488 | * Dirty memory-backed inode against a filesystem other | |
489 | * than the kernel-internal bdev filesystem. Skip the | |
490 | * entire superblock. | |
491 | */ | |
492 | break; | |
493 | } | |
494 | ||
84a89245 | 495 | if (inode->i_state & (I_NEW | I_WILL_FREE)) { |
7ef0d737 NP |
496 | requeue_io(inode); |
497 | continue; | |
498 | } | |
499 | ||
1da177e4 LT |
500 | if (wbc->nonblocking && bdi_write_congested(bdi)) { |
501 | wbc->encountered_congestion = 1; | |
7b0de42d | 502 | if (!sb_is_blkdev_sb(sb)) |
1da177e4 | 503 | break; /* Skip a congested fs */ |
0e0f4fc2 | 504 | requeue_io(inode); |
1da177e4 LT |
505 | continue; /* Skip a congested blockdev */ |
506 | } | |
507 | ||
508 | if (wbc->bdi && bdi != wbc->bdi) { | |
7b0de42d | 509 | if (!sb_is_blkdev_sb(sb)) |
1da177e4 | 510 | break; /* fs has the wrong queue */ |
0e0f4fc2 | 511 | requeue_io(inode); |
1da177e4 LT |
512 | continue; /* blockdev has wrong queue */ |
513 | } | |
514 | ||
d2caa3c5 JL |
515 | /* |
516 | * Was this inode dirtied after sync_sb_inodes was called? | |
517 | * This keeps sync from extra jobs and livelock. | |
518 | */ | |
519 | if (inode_dirtied_after(inode, start)) | |
1da177e4 LT |
520 | break; |
521 | ||
1da177e4 LT |
522 | /* Is another pdflush already flushing this queue? */ |
523 | if (current_is_pdflush() && !writeback_acquire(bdi)) | |
524 | break; | |
525 | ||
84a89245 | 526 | BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); |
1da177e4 LT |
527 | __iget(inode); |
528 | pages_skipped = wbc->pages_skipped; | |
529 | __writeback_single_inode(inode, wbc); | |
1da177e4 LT |
530 | if (current_is_pdflush()) |
531 | writeback_release(bdi); | |
532 | if (wbc->pages_skipped != pages_skipped) { | |
533 | /* | |
534 | * writeback is not making progress due to locked | |
535 | * buffers. Skip this inode for now. | |
536 | */ | |
f57b9b7b | 537 | redirty_tail(inode); |
1da177e4 LT |
538 | } |
539 | spin_unlock(&inode_lock); | |
1da177e4 | 540 | iput(inode); |
4ffc8444 | 541 | cond_resched(); |
1da177e4 | 542 | spin_lock(&inode_lock); |
8bc3be27 FW |
543 | if (wbc->nr_to_write <= 0) { |
544 | wbc->more_io = 1; | |
1da177e4 | 545 | break; |
8bc3be27 FW |
546 | } |
547 | if (!list_empty(&sb->s_more_io)) | |
548 | wbc->more_io = 1; | |
1da177e4 | 549 | } |
38f21977 NP |
550 | |
551 | if (sync) { | |
552 | struct inode *inode, *old_inode = NULL; | |
553 | ||
554 | /* | |
555 | * Data integrity sync. Must wait for all pages under writeback, | |
556 | * because there may have been pages dirtied before our sync | |
557 | * call, but which had writeout started before we write it out. | |
558 | * In which case, the inode may not be on the dirty list, but | |
559 | * we still have to wait for that writeout. | |
560 | */ | |
561 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { | |
562 | struct address_space *mapping; | |
563 | ||
b6fac63c WF |
564 | if (inode->i_state & |
565 | (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) | |
38f21977 NP |
566 | continue; |
567 | mapping = inode->i_mapping; | |
568 | if (mapping->nrpages == 0) | |
569 | continue; | |
570 | __iget(inode); | |
571 | spin_unlock(&inode_lock); | |
572 | /* | |
573 | * We hold a reference to 'inode' so it couldn't have | |
574 | * been removed from s_inodes list while we dropped the | |
575 | * inode_lock. We cannot iput the inode now as we can | |
576 | * be holding the last reference and we cannot iput it | |
577 | * under inode_lock. So we keep the reference and iput | |
578 | * it later. | |
579 | */ | |
580 | iput(old_inode); | |
581 | old_inode = inode; | |
582 | ||
583 | filemap_fdatawait(mapping); | |
584 | ||
585 | cond_resched(); | |
586 | ||
587 | spin_lock(&inode_lock); | |
588 | } | |
589 | spin_unlock(&inode_lock); | |
590 | iput(old_inode); | |
591 | } else | |
592 | spin_unlock(&inode_lock); | |
593 | ||
1da177e4 LT |
594 | return; /* Leave any unwritten inodes on s_io */ |
595 | } | |
4ee6afd3 AB |
596 | EXPORT_SYMBOL_GPL(generic_sync_sb_inodes); |
597 | ||
598 | static void sync_sb_inodes(struct super_block *sb, | |
599 | struct writeback_control *wbc) | |
600 | { | |
601 | generic_sync_sb_inodes(sb, wbc); | |
602 | } | |
1da177e4 LT |
603 | |
604 | /* | |
605 | * Start writeback of dirty pagecache data against all unlocked inodes. | |
606 | * | |
607 | * Note: | |
608 | * We don't need to grab a reference to superblock here. If it has non-empty | |
609 | * ->s_dirty it's hadn't been killed yet and kill_super() won't proceed | |
2c136579 | 610 | * past sync_inodes_sb() until the ->s_dirty/s_io/s_more_io lists are all |
1da177e4 LT |
611 | * empty. Since __sync_single_inode() regains inode_lock before it finally moves |
612 | * inode from superblock lists we are OK. | |
613 | * | |
614 | * If `older_than_this' is non-zero then only flush inodes which have a | |
615 | * flushtime older than *older_than_this. | |
616 | * | |
617 | * If `bdi' is non-zero then we will scan the first inode against each | |
618 | * superblock until we find the matching ones. One group will be the dirty | |
619 | * inodes against a filesystem. Then when we hit the dummy blockdev superblock, | |
620 | * sync_sb_inodes will seekout the blockdev which matches `bdi'. Maybe not | |
621 | * super-efficient but we're about to do a ton of I/O... | |
622 | */ | |
623 | void | |
624 | writeback_inodes(struct writeback_control *wbc) | |
625 | { | |
626 | struct super_block *sb; | |
627 | ||
628 | might_sleep(); | |
629 | spin_lock(&sb_lock); | |
630 | restart: | |
797074e4 | 631 | list_for_each_entry_reverse(sb, &super_blocks, s_list) { |
08d8e974 | 632 | if (sb_has_dirty_inodes(sb)) { |
1da177e4 LT |
633 | /* we're making our own get_super here */ |
634 | sb->s_count++; | |
635 | spin_unlock(&sb_lock); | |
636 | /* | |
637 | * If we can't get the readlock, there's no sense in | |
638 | * waiting around, most of the time the FS is going to | |
639 | * be unmounted by the time it is released. | |
640 | */ | |
641 | if (down_read_trylock(&sb->s_umount)) { | |
ae8547b0 | 642 | if (sb->s_root) |
1da177e4 | 643 | sync_sb_inodes(sb, wbc); |
1da177e4 LT |
644 | up_read(&sb->s_umount); |
645 | } | |
646 | spin_lock(&sb_lock); | |
647 | if (__put_super_and_need_restart(sb)) | |
648 | goto restart; | |
649 | } | |
650 | if (wbc->nr_to_write <= 0) | |
651 | break; | |
652 | } | |
653 | spin_unlock(&sb_lock); | |
654 | } | |
655 | ||
656 | /* | |
657 | * writeback and wait upon the filesystem's dirty inodes. The caller will | |
4f5a99d6 | 658 | * do this in two passes - one to write, and one to wait. |
1da177e4 LT |
659 | * |
660 | * A finite limit is set on the number of pages which will be written. | |
661 | * To prevent infinite livelock of sys_sync(). | |
662 | * | |
663 | * We add in the number of potentially dirty inodes, because each inode write | |
664 | * can dirty pagecache in the underlying blockdev. | |
665 | */ | |
666 | void sync_inodes_sb(struct super_block *sb, int wait) | |
667 | { | |
668 | struct writeback_control wbc = { | |
4f5a99d6 | 669 | .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE, |
111ebb6e OH |
670 | .range_start = 0, |
671 | .range_end = LLONG_MAX, | |
1da177e4 | 672 | }; |
1da177e4 | 673 | |
38f21977 NP |
674 | if (!wait) { |
675 | unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); | |
676 | unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); | |
677 | ||
678 | wbc.nr_to_write = nr_dirty + nr_unstable + | |
679 | (inodes_stat.nr_inodes - inodes_stat.nr_unused); | |
680 | } else | |
681 | wbc.nr_to_write = LONG_MAX; /* doesn't actually matter */ | |
682 | ||
1da177e4 | 683 | sync_sb_inodes(sb, &wbc); |
1da177e4 LT |
684 | } |
685 | ||
1da177e4 | 686 | /** |
7f04c26d AA |
687 | * write_inode_now - write an inode to disk |
688 | * @inode: inode to write to disk | |
689 | * @sync: whether the write should be synchronous or not | |
690 | * | |
691 | * This function commits an inode to disk immediately if it is dirty. This is | |
692 | * primarily needed by knfsd. | |
1da177e4 | 693 | * |
7f04c26d | 694 | * The caller must either have a ref on the inode or must have set I_WILL_FREE. |
1da177e4 | 695 | */ |
1da177e4 LT |
696 | int write_inode_now(struct inode *inode, int sync) |
697 | { | |
698 | int ret; | |
699 | struct writeback_control wbc = { | |
700 | .nr_to_write = LONG_MAX, | |
18914b18 | 701 | .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, |
111ebb6e OH |
702 | .range_start = 0, |
703 | .range_end = LLONG_MAX, | |
1da177e4 LT |
704 | }; |
705 | ||
706 | if (!mapping_cap_writeback_dirty(inode->i_mapping)) | |
49364ce2 | 707 | wbc.nr_to_write = 0; |
1da177e4 LT |
708 | |
709 | might_sleep(); | |
710 | spin_lock(&inode_lock); | |
711 | ret = __writeback_single_inode(inode, &wbc); | |
712 | spin_unlock(&inode_lock); | |
713 | if (sync) | |
1c0eeaf5 | 714 | inode_sync_wait(inode); |
1da177e4 LT |
715 | return ret; |
716 | } | |
717 | EXPORT_SYMBOL(write_inode_now); | |
718 | ||
719 | /** | |
720 | * sync_inode - write an inode and its pages to disk. | |
721 | * @inode: the inode to sync | |
722 | * @wbc: controls the writeback mode | |
723 | * | |
724 | * sync_inode() will write an inode and its pages to disk. It will also | |
725 | * correctly update the inode on its superblock's dirty inode lists and will | |
726 | * update inode->i_state. | |
727 | * | |
728 | * The caller must have a ref on the inode. | |
729 | */ | |
730 | int sync_inode(struct inode *inode, struct writeback_control *wbc) | |
731 | { | |
732 | int ret; | |
733 | ||
734 | spin_lock(&inode_lock); | |
735 | ret = __writeback_single_inode(inode, wbc); | |
736 | spin_unlock(&inode_lock); | |
737 | return ret; | |
738 | } | |
739 | EXPORT_SYMBOL(sync_inode); | |
740 | ||
741 | /** | |
742 | * generic_osync_inode - flush all dirty data for a given inode to disk | |
743 | * @inode: inode to write | |
67be2dd1 | 744 | * @mapping: the address_space that should be flushed |
1da177e4 LT |
745 | * @what: what to write and wait upon |
746 | * | |
747 | * This can be called by file_write functions for files which have the | |
748 | * O_SYNC flag set, to flush dirty writes to disk. | |
749 | * | |
750 | * @what is a bitmask, specifying which part of the inode's data should be | |
b8887e6e | 751 | * written and waited upon. |
1da177e4 LT |
752 | * |
753 | * OSYNC_DATA: i_mapping's dirty data | |
754 | * OSYNC_METADATA: the buffers at i_mapping->private_list | |
755 | * OSYNC_INODE: the inode itself | |
756 | */ | |
757 | ||
758 | int generic_osync_inode(struct inode *inode, struct address_space *mapping, int what) | |
759 | { | |
760 | int err = 0; | |
761 | int need_write_inode_now = 0; | |
762 | int err2; | |
763 | ||
1da177e4 LT |
764 | if (what & OSYNC_DATA) |
765 | err = filemap_fdatawrite(mapping); | |
766 | if (what & (OSYNC_METADATA|OSYNC_DATA)) { | |
767 | err2 = sync_mapping_buffers(mapping); | |
768 | if (!err) | |
769 | err = err2; | |
770 | } | |
771 | if (what & OSYNC_DATA) { | |
772 | err2 = filemap_fdatawait(mapping); | |
773 | if (!err) | |
774 | err = err2; | |
775 | } | |
1da177e4 LT |
776 | |
777 | spin_lock(&inode_lock); | |
778 | if ((inode->i_state & I_DIRTY) && | |
779 | ((what & OSYNC_INODE) || (inode->i_state & I_DIRTY_DATASYNC))) | |
780 | need_write_inode_now = 1; | |
781 | spin_unlock(&inode_lock); | |
782 | ||
783 | if (need_write_inode_now) { | |
784 | err2 = write_inode_now(inode, 1); | |
785 | if (!err) | |
786 | err = err2; | |
787 | } | |
788 | else | |
1c0eeaf5 | 789 | inode_sync_wait(inode); |
1da177e4 LT |
790 | |
791 | return err; | |
792 | } | |
1da177e4 | 793 | EXPORT_SYMBOL(generic_osync_inode); |