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-rw-r--r--fs/fs-writeback.c1065
1 files changed, 785 insertions, 280 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index c54226be5294..da86ef58e427 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -19,171 +19,223 @@
19#include <linux/sched.h> 19#include <linux/sched.h>
20#include <linux/fs.h> 20#include <linux/fs.h>
21#include <linux/mm.h> 21#include <linux/mm.h>
22#include <linux/kthread.h>
23#include <linux/freezer.h>
22#include <linux/writeback.h> 24#include <linux/writeback.h>
23#include <linux/blkdev.h> 25#include <linux/blkdev.h>
24#include <linux/backing-dev.h> 26#include <linux/backing-dev.h>
25#include <linux/buffer_head.h> 27#include <linux/buffer_head.h>
26#include "internal.h" 28#include "internal.h"
27 29
30#define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info)
28 31
29/** 32/*
30 * writeback_acquire - attempt to get exclusive writeback access to a device 33 * We don't actually have pdflush, but this one is exported though /proc...
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 */ 34 */
41static int writeback_acquire(struct backing_dev_info *bdi) 35int nr_pdflush_threads;
36
37/*
38 * Work items for the bdi_writeback threads
39 */
40struct bdi_work {
41 struct list_head list;
42 struct list_head wait_list;
43 struct rcu_head rcu_head;
44
45 unsigned long seen;
46 atomic_t pending;
47
48 struct super_block *sb;
49 unsigned long nr_pages;
50 enum writeback_sync_modes sync_mode;
51
52 unsigned long state;
53};
54
55enum {
56 WS_USED_B = 0,
57 WS_ONSTACK_B,
58};
59
60#define WS_USED (1 << WS_USED_B)
61#define WS_ONSTACK (1 << WS_ONSTACK_B)
62
63static inline bool bdi_work_on_stack(struct bdi_work *work)
42{ 64{
43 return !test_and_set_bit(BDI_pdflush, &bdi->state); 65 return test_bit(WS_ONSTACK_B, &work->state);
66}
67
68static inline void bdi_work_init(struct bdi_work *work,
69 struct writeback_control *wbc)
70{
71 INIT_RCU_HEAD(&work->rcu_head);
72 work->sb = wbc->sb;
73 work->nr_pages = wbc->nr_to_write;
74 work->sync_mode = wbc->sync_mode;
75 work->state = WS_USED;
76}
77
78static inline void bdi_work_init_on_stack(struct bdi_work *work,
79 struct writeback_control *wbc)
80{
81 bdi_work_init(work, wbc);
82 work->state |= WS_ONSTACK;
44} 83}
45 84
46/** 85/**
47 * writeback_in_progress - determine whether there is writeback in progress 86 * writeback_in_progress - determine whether there is writeback in progress
48 * @bdi: the device's backing_dev_info structure. 87 * @bdi: the device's backing_dev_info structure.
49 * 88 *
50 * Determine whether there is writeback in progress against a backing device. 89 * Determine whether there is writeback waiting to be handled against a
90 * backing device.
51 */ 91 */
52int writeback_in_progress(struct backing_dev_info *bdi) 92int writeback_in_progress(struct backing_dev_info *bdi)
53{ 93{
54 return test_bit(BDI_pdflush, &bdi->state); 94 return !list_empty(&bdi->work_list);
55} 95}
56 96
57/** 97static void bdi_work_clear(struct bdi_work *work)
58 * writeback_release - relinquish exclusive writeback access against a device.
59 * @bdi: the device's backing_dev_info structure
60 */
61static void writeback_release(struct backing_dev_info *bdi)
62{ 98{
63 BUG_ON(!writeback_in_progress(bdi)); 99 clear_bit(WS_USED_B, &work->state);
64 clear_bit(BDI_pdflush, &bdi->state); 100 smp_mb__after_clear_bit();
101 wake_up_bit(&work->state, WS_USED_B);
65} 102}
66 103
67static noinline void block_dump___mark_inode_dirty(struct inode *inode) 104static void bdi_work_free(struct rcu_head *head)
68{ 105{
69 if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { 106 struct bdi_work *work = container_of(head, struct bdi_work, rcu_head);
70 struct dentry *dentry;
71 const char *name = "?";
72 107
73 dentry = d_find_alias(inode); 108 if (!bdi_work_on_stack(work))
74 if (dentry) { 109 kfree(work);
75 spin_lock(&dentry->d_lock); 110 else
76 name = (const char *) dentry->d_name.name; 111 bdi_work_clear(work);
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} 112}
88 113
89/** 114static void wb_work_complete(struct bdi_work *work)
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 */
116void __mark_inode_dirty(struct inode *inode, int flags)
117{ 115{
118 struct super_block *sb = inode->i_sb; 116 const enum writeback_sync_modes sync_mode = work->sync_mode;
119 117
120 /* 118 /*
121 * Don't do this for I_DIRTY_PAGES - that doesn't actually 119 * For allocated work, we can clear the done/seen bit right here.
122 * dirty the inode itself 120 * For on-stack work, we need to postpone both the clear and free
121 * to after the RCU grace period, since the stack could be invalidated
122 * as soon as bdi_work_clear() has done the wakeup.
123 */ 123 */
124 if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { 124 if (!bdi_work_on_stack(work))
125 if (sb->s_op->dirty_inode) 125 bdi_work_clear(work);
126 sb->s_op->dirty_inode(inode); 126 if (sync_mode == WB_SYNC_NONE || bdi_work_on_stack(work))
127 } 127 call_rcu(&work->rcu_head, bdi_work_free);
128}
128 129
130static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work)
131{
129 /* 132 /*
130 * make sure that changes are seen by all cpus before we test i_state 133 * The caller has retrieved the work arguments from this work,
131 * -- mikulas 134 * drop our reference. If this is the last ref, delete and free it
132 */ 135 */
133 smp_mb(); 136 if (atomic_dec_and_test(&work->pending)) {
137 struct backing_dev_info *bdi = wb->bdi;
134 138
135 /* avoid the locking if we can */ 139 spin_lock(&bdi->wb_lock);
136 if ((inode->i_state & flags) == flags) 140 list_del_rcu(&work->list);
137 return; 141 spin_unlock(&bdi->wb_lock);
138 142
139 if (unlikely(block_dump)) 143 wb_work_complete(work);
140 block_dump___mark_inode_dirty(inode); 144 }
141 145}
142 spin_lock(&inode_lock);
143 if ((inode->i_state & flags) != flags) {
144 const int was_dirty = inode->i_state & I_DIRTY;
145 146
146 inode->i_state |= flags; 147static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work)
148{
149 if (work) {
150 work->seen = bdi->wb_mask;
151 BUG_ON(!work->seen);
152 atomic_set(&work->pending, bdi->wb_cnt);
153 BUG_ON(!bdi->wb_cnt);
147 154
148 /* 155 /*
149 * If the inode is being synced, just update its dirty state. 156 * Make sure stores are seen before it appears on the list
150 * The unlocker will place the inode on the appropriate
151 * superblock list, based upon its state.
152 */ 157 */
153 if (inode->i_state & I_SYNC) 158 smp_mb();
154 goto out;
155 159
156 /* 160 spin_lock(&bdi->wb_lock);
157 * Only add valid (hashed) inodes to the superblock's 161 list_add_tail_rcu(&work->list, &bdi->work_list);
158 * dirty list. Add blockdev inodes as well. 162 spin_unlock(&bdi->wb_lock);
159 */ 163 }
160 if (!S_ISBLK(inode->i_mode)) { 164
161 if (hlist_unhashed(&inode->i_hash)) 165 /*
162 goto out; 166 * If the default thread isn't there, make sure we add it. When
163 } 167 * it gets created and wakes up, we'll run this work.
164 if (inode->i_state & (I_FREEING|I_CLEAR)) 168 */
165 goto out; 169 if (unlikely(list_empty_careful(&bdi->wb_list)))
170 wake_up_process(default_backing_dev_info.wb.task);
171 else {
172 struct bdi_writeback *wb = &bdi->wb;
166 173
167 /* 174 /*
168 * If the inode was already on s_dirty/s_io/s_more_io, don't 175 * If we failed allocating the bdi work item, wake up the wb
169 * reposition it (that would break s_dirty time-ordering). 176 * thread always. As a safety precaution, it'll flush out
177 * everything
170 */ 178 */
171 if (!was_dirty) { 179 if (!wb_has_dirty_io(wb)) {
172 inode->dirtied_when = jiffies; 180 if (work)
173 list_move(&inode->i_list, &sb->s_dirty); 181 wb_clear_pending(wb, work);
174 } 182 } else if (wb->task)
183 wake_up_process(wb->task);
175 } 184 }
176out:
177 spin_unlock(&inode_lock);
178} 185}
179 186
180EXPORT_SYMBOL(__mark_inode_dirty); 187/*
188 * Used for on-stack allocated work items. The caller needs to wait until
189 * the wb threads have acked the work before it's safe to continue.
190 */
191static void bdi_wait_on_work_clear(struct bdi_work *work)
192{
193 wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait,
194 TASK_UNINTERRUPTIBLE);
195}
181 196
182static int write_inode(struct inode *inode, int sync) 197static struct bdi_work *bdi_alloc_work(struct writeback_control *wbc)
183{ 198{
184 if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode)) 199 struct bdi_work *work;
185 return inode->i_sb->s_op->write_inode(inode, sync); 200
186 return 0; 201 work = kmalloc(sizeof(*work), GFP_ATOMIC);
202 if (work)
203 bdi_work_init(work, wbc);
204
205 return work;
206}
207
208void bdi_start_writeback(struct writeback_control *wbc)
209{
210 const bool must_wait = wbc->sync_mode == WB_SYNC_ALL;
211 struct bdi_work work_stack, *work = NULL;
212
213 if (!must_wait)
214 work = bdi_alloc_work(wbc);
215
216 if (!work) {
217 work = &work_stack;
218 bdi_work_init_on_stack(work, wbc);
219 }
220
221 bdi_queue_work(wbc->bdi, work);
222
223 /*
224 * If the sync mode is WB_SYNC_ALL, block waiting for the work to
225 * complete. If not, we only need to wait for the work to be started,
226 * if we allocated it on-stack. We use the same mechanism, if the
227 * wait bit is set in the bdi_work struct, then threads will not
228 * clear pending until after they are done.
229 *
230 * Note that work == &work_stack if must_wait is true, so we don't
231 * need to do call_rcu() here ever, since the completion path will
232 * have done that for us.
233 */
234 if (must_wait || work == &work_stack) {
235 bdi_wait_on_work_clear(work);
236 if (work != &work_stack)
237 call_rcu(&work->rcu_head, bdi_work_free);
238 }
187} 239}
188 240
189/* 241/*
@@ -191,31 +243,32 @@ static int write_inode(struct inode *inode, int sync)
191 * furthest end of its superblock's dirty-inode list. 243 * furthest end of its superblock's dirty-inode list.
192 * 244 *
193 * Before stamping the inode's ->dirtied_when, we check to see whether it is 245 * 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 246 * already the most-recently-dirtied inode on the b_dirty list. If that is
195 * the case then the inode must have been redirtied while it was being written 247 * the case then the inode must have been redirtied while it was being written
196 * out and we don't reset its dirtied_when. 248 * out and we don't reset its dirtied_when.
197 */ 249 */
198static void redirty_tail(struct inode *inode) 250static void redirty_tail(struct inode *inode)
199{ 251{
200 struct super_block *sb = inode->i_sb; 252 struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
201 253
202 if (!list_empty(&sb->s_dirty)) { 254 if (!list_empty(&wb->b_dirty)) {
203 struct inode *tail_inode; 255 struct inode *tail;
204 256
205 tail_inode = list_entry(sb->s_dirty.next, struct inode, i_list); 257 tail = list_entry(wb->b_dirty.next, struct inode, i_list);
206 if (time_before(inode->dirtied_when, 258 if (time_before(inode->dirtied_when, tail->dirtied_when))
207 tail_inode->dirtied_when))
208 inode->dirtied_when = jiffies; 259 inode->dirtied_when = jiffies;
209 } 260 }
210 list_move(&inode->i_list, &sb->s_dirty); 261 list_move(&inode->i_list, &wb->b_dirty);
211} 262}
212 263
213/* 264/*
214 * requeue inode for re-scanning after sb->s_io list is exhausted. 265 * requeue inode for re-scanning after bdi->b_io list is exhausted.
215 */ 266 */
216static void requeue_io(struct inode *inode) 267static void requeue_io(struct inode *inode)
217{ 268{
218 list_move(&inode->i_list, &inode->i_sb->s_more_io); 269 struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
270
271 list_move(&inode->i_list, &wb->b_more_io);
219} 272}
220 273
221static void inode_sync_complete(struct inode *inode) 274static void inode_sync_complete(struct inode *inode)
@@ -262,20 +315,18 @@ static void move_expired_inodes(struct list_head *delaying_queue,
262/* 315/*
263 * Queue all expired dirty inodes for io, eldest first. 316 * Queue all expired dirty inodes for io, eldest first.
264 */ 317 */
265static void queue_io(struct super_block *sb, 318static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this)
266 unsigned long *older_than_this)
267{ 319{
268 list_splice_init(&sb->s_more_io, sb->s_io.prev); 320 list_splice_init(&wb->b_more_io, wb->b_io.prev);
269 move_expired_inodes(&sb->s_dirty, &sb->s_io, older_than_this); 321 move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this);
270} 322}
271 323
272int sb_has_dirty_inodes(struct super_block *sb) 324static int write_inode(struct inode *inode, int sync)
273{ 325{
274 return !list_empty(&sb->s_dirty) || 326 if (inode->i_sb->s_op->write_inode && !is_bad_inode(inode))
275 !list_empty(&sb->s_io) || 327 return inode->i_sb->s_op->write_inode(inode, sync);
276 !list_empty(&sb->s_more_io); 328 return 0;
277} 329}
278EXPORT_SYMBOL(sb_has_dirty_inodes);
279 330
280/* 331/*
281 * Wait for writeback on an inode to complete. 332 * Wait for writeback on an inode to complete.
@@ -322,11 +373,11 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
322 if (inode->i_state & I_SYNC) { 373 if (inode->i_state & I_SYNC) {
323 /* 374 /*
324 * If this inode is locked for writeback and we are not doing 375 * If this inode is locked for writeback and we are not doing
325 * writeback-for-data-integrity, move it to s_more_io so that 376 * writeback-for-data-integrity, move it to b_more_io so that
326 * writeback can proceed with the other inodes on s_io. 377 * writeback can proceed with the other inodes on s_io.
327 * 378 *
328 * We'll have another go at writing back this inode when we 379 * We'll have another go at writing back this inode when we
329 * completed a full scan of s_io. 380 * completed a full scan of b_io.
330 */ 381 */
331 if (!wait) { 382 if (!wait) {
332 requeue_io(inode); 383 requeue_io(inode);
@@ -371,11 +422,11 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
371 /* 422 /*
372 * We didn't write back all the pages. nfs_writepages() 423 * We didn't write back all the pages. nfs_writepages()
373 * sometimes bales out without doing anything. Redirty 424 * sometimes bales out without doing anything. Redirty
374 * the inode; Move it from s_io onto s_more_io/s_dirty. 425 * the inode; Move it from b_io onto b_more_io/b_dirty.
375 */ 426 */
376 /* 427 /*
377 * akpm: if the caller was the kupdate function we put 428 * akpm: if the caller was the kupdate function we put
378 * this inode at the head of s_dirty so it gets first 429 * this inode at the head of b_dirty so it gets first
379 * consideration. Otherwise, move it to the tail, for 430 * consideration. Otherwise, move it to the tail, for
380 * the reasons described there. I'm not really sure 431 * the reasons described there. I'm not really sure
381 * how much sense this makes. Presumably I had a good 432 * how much sense this makes. Presumably I had a good
@@ -385,7 +436,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
385 if (wbc->for_kupdate) { 436 if (wbc->for_kupdate) {
386 /* 437 /*
387 * For the kupdate function we move the inode 438 * For the kupdate function we move the inode
388 * to s_more_io so it will get more writeout as 439 * to b_more_io so it will get more writeout as
389 * soon as the queue becomes uncongested. 440 * soon as the queue becomes uncongested.
390 */ 441 */
391 inode->i_state |= I_DIRTY_PAGES; 442 inode->i_state |= I_DIRTY_PAGES;
@@ -434,50 +485,84 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
434} 485}
435 486
436/* 487/*
437 * Write out a superblock's list of dirty inodes. A wait will be performed 488 * For WB_SYNC_NONE writeback, the caller does not have the sb pinned
438 * upon no inodes, all inodes or the final one, depending upon sync_mode. 489 * before calling writeback. So make sure that we do pin it, so it doesn't
439 * 490 * go away while we are writing inodes from it.
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 *
443 * If we're a pdflush thread, then implement pdflush collision avoidance
444 * against the entire list.
445 * 491 *
446 * If `bdi' is non-zero then we're being asked to writeback a specific queue. 492 * Returns 0 if the super was successfully pinned (or pinning wasn't needed),
447 * This function assumes that the blockdev superblock's inodes are backed by 493 * 1 if we failed.
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
459 * throttled threads: we don't want them all piling up on inode_sync_wait.
460 */ 494 */
461void generic_sync_sb_inodes(struct super_block *sb, 495static int pin_sb_for_writeback(struct writeback_control *wbc,
496 struct inode *inode)
497{
498 struct super_block *sb = inode->i_sb;
499
500 /*
501 * Caller must already hold the ref for this
502 */
503 if (wbc->sync_mode == WB_SYNC_ALL) {
504 WARN_ON(!rwsem_is_locked(&sb->s_umount));
505 return 0;
506 }
507
508 spin_lock(&sb_lock);
509 sb->s_count++;
510 if (down_read_trylock(&sb->s_umount)) {
511 if (sb->s_root) {
512 spin_unlock(&sb_lock);
513 return 0;
514 }
515 /*
516 * umounted, drop rwsem again and fall through to failure
517 */
518 up_read(&sb->s_umount);
519 }
520
521 sb->s_count--;
522 spin_unlock(&sb_lock);
523 return 1;
524}
525
526static void unpin_sb_for_writeback(struct writeback_control *wbc,
527 struct inode *inode)
528{
529 struct super_block *sb = inode->i_sb;
530
531 if (wbc->sync_mode == WB_SYNC_ALL)
532 return;
533
534 up_read(&sb->s_umount);
535 put_super(sb);
536}
537
538static void writeback_inodes_wb(struct bdi_writeback *wb,
462 struct writeback_control *wbc) 539 struct writeback_control *wbc)
463{ 540{
541 struct super_block *sb = wbc->sb;
542 const int is_blkdev_sb = sb_is_blkdev_sb(sb);
464 const unsigned long start = jiffies; /* livelock avoidance */ 543 const unsigned long start = jiffies; /* livelock avoidance */
465 int sync = wbc->sync_mode == WB_SYNC_ALL;
466 544
467 spin_lock(&inode_lock); 545 spin_lock(&inode_lock);
468 if (!wbc->for_kupdate || list_empty(&sb->s_io))
469 queue_io(sb, wbc->older_than_this);
470 546
471 while (!list_empty(&sb->s_io)) { 547 if (!wbc->for_kupdate || list_empty(&wb->b_io))
472 struct inode *inode = list_entry(sb->s_io.prev, 548 queue_io(wb, wbc->older_than_this);
549
550 while (!list_empty(&wb->b_io)) {
551 struct inode *inode = list_entry(wb->b_io.prev,
473 struct inode, i_list); 552 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; 553 long pages_skipped;
477 554
478 if (!bdi_cap_writeback_dirty(bdi)) { 555 /*
556 * super block given and doesn't match, skip this inode
557 */
558 if (sb && sb != inode->i_sb) {
559 redirty_tail(inode);
560 continue;
561 }
562
563 if (!bdi_cap_writeback_dirty(wb->bdi)) {
479 redirty_tail(inode); 564 redirty_tail(inode);
480 if (sb_is_blkdev_sb(sb)) { 565 if (is_blkdev_sb) {
481 /* 566 /*
482 * Dirty memory-backed blockdev: the ramdisk 567 * Dirty memory-backed blockdev: the ramdisk
483 * driver does this. Skip just this inode 568 * driver does this. Skip just this inode
@@ -497,21 +582,14 @@ void generic_sync_sb_inodes(struct super_block *sb,
497 continue; 582 continue;
498 } 583 }
499 584
500 if (wbc->nonblocking && bdi_write_congested(bdi)) { 585 if (wbc->nonblocking && bdi_write_congested(wb->bdi)) {
501 wbc->encountered_congestion = 1; 586 wbc->encountered_congestion = 1;
502 if (!sb_is_blkdev_sb(sb)) 587 if (!is_blkdev_sb)
503 break; /* Skip a congested fs */ 588 break; /* Skip a congested fs */
504 requeue_io(inode); 589 requeue_io(inode);
505 continue; /* Skip a congested blockdev */ 590 continue; /* Skip a congested blockdev */
506 } 591 }
507 592
508 if (wbc->bdi && bdi != wbc->bdi) {
509 if (!sb_is_blkdev_sb(sb))
510 break; /* fs has the wrong queue */
511 requeue_io(inode);
512 continue; /* blockdev has wrong queue */
513 }
514
515 /* 593 /*
516 * Was this inode dirtied after sync_sb_inodes was called? 594 * Was this inode dirtied after sync_sb_inodes was called?
517 * This keeps sync from extra jobs and livelock. 595 * This keeps sync from extra jobs and livelock.
@@ -519,16 +597,16 @@ void generic_sync_sb_inodes(struct super_block *sb,
519 if (inode_dirtied_after(inode, start)) 597 if (inode_dirtied_after(inode, start))
520 break; 598 break;
521 599
522 /* Is another pdflush already flushing this queue? */ 600 if (pin_sb_for_writeback(wbc, inode)) {
523 if (current_is_pdflush() && !writeback_acquire(bdi)) 601 requeue_io(inode);
524 break; 602 continue;
603 }
525 604
526 BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); 605 BUG_ON(inode->i_state & (I_FREEING | I_CLEAR));
527 __iget(inode); 606 __iget(inode);
528 pages_skipped = wbc->pages_skipped; 607 pages_skipped = wbc->pages_skipped;
529 writeback_single_inode(inode, wbc); 608 writeback_single_inode(inode, wbc);
530 if (current_is_pdflush()) 609 unpin_sb_for_writeback(wbc, inode);
531 writeback_release(bdi);
532 if (wbc->pages_skipped != pages_skipped) { 610 if (wbc->pages_skipped != pages_skipped) {
533 /* 611 /*
534 * writeback is not making progress due to locked 612 * writeback is not making progress due to locked
@@ -544,144 +622,571 @@ void generic_sync_sb_inodes(struct super_block *sb,
544 wbc->more_io = 1; 622 wbc->more_io = 1;
545 break; 623 break;
546 } 624 }
547 if (!list_empty(&sb->s_more_io)) 625 if (!list_empty(&wb->b_more_io))
548 wbc->more_io = 1; 626 wbc->more_io = 1;
549 } 627 }
550 628
551 if (sync) { 629 spin_unlock(&inode_lock);
552 struct inode *inode, *old_inode = NULL; 630 /* Leave any unwritten inodes on b_io */
631}
632
633void writeback_inodes_wbc(struct writeback_control *wbc)
634{
635 struct backing_dev_info *bdi = wbc->bdi;
553 636
637 writeback_inodes_wb(&bdi->wb, wbc);
638}
639
640/*
641 * The maximum number of pages to writeout in a single bdi flush/kupdate
642 * operation. We do this so we don't hold I_SYNC against an inode for
643 * enormous amounts of time, which would block a userspace task which has
644 * been forced to throttle against that inode. Also, the code reevaluates
645 * the dirty each time it has written this many pages.
646 */
647#define MAX_WRITEBACK_PAGES 1024
648
649static inline bool over_bground_thresh(void)
650{
651 unsigned long background_thresh, dirty_thresh;
652
653 get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL);
654
655 return (global_page_state(NR_FILE_DIRTY) +
656 global_page_state(NR_UNSTABLE_NFS) >= background_thresh);
657}
658
659/*
660 * Explicit flushing or periodic writeback of "old" data.
661 *
662 * Define "old": the first time one of an inode's pages is dirtied, we mark the
663 * dirtying-time in the inode's address_space. So this periodic writeback code
664 * just walks the superblock inode list, writing back any inodes which are
665 * older than a specific point in time.
666 *
667 * Try to run once per dirty_writeback_interval. But if a writeback event
668 * takes longer than a dirty_writeback_interval interval, then leave a
669 * one-second gap.
670 *
671 * older_than_this takes precedence over nr_to_write. So we'll only write back
672 * all dirty pages if they are all attached to "old" mappings.
673 */
674static long wb_writeback(struct bdi_writeback *wb, long nr_pages,
675 struct super_block *sb,
676 enum writeback_sync_modes sync_mode, int for_kupdate)
677{
678 struct writeback_control wbc = {
679 .bdi = wb->bdi,
680 .sb = sb,
681 .sync_mode = sync_mode,
682 .older_than_this = NULL,
683 .for_kupdate = for_kupdate,
684 .range_cyclic = 1,
685 };
686 unsigned long oldest_jif;
687 long wrote = 0;
688
689 if (wbc.for_kupdate) {
690 wbc.older_than_this = &oldest_jif;
691 oldest_jif = jiffies -
692 msecs_to_jiffies(dirty_expire_interval * 10);
693 }
694
695 for (;;) {
554 /* 696 /*
555 * Data integrity sync. Must wait for all pages under writeback, 697 * Don't flush anything for non-integrity writeback where
556 * because there may have been pages dirtied before our sync 698 * no nr_pages was given
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 */ 699 */
561 list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { 700 if (!for_kupdate && nr_pages <= 0 && sync_mode == WB_SYNC_NONE)
562 struct address_space *mapping; 701 break;
563 702
564 if (inode->i_state & 703 /*
565 (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) 704 * If no specific pages were given and this is just a
566 continue; 705 * periodic background writeout and we are below the
567 mapping = inode->i_mapping; 706 * background dirty threshold, don't do anything
568 if (mapping->nrpages == 0) 707 */
708 if (for_kupdate && nr_pages <= 0 && !over_bground_thresh())
709 break;
710
711 wbc.more_io = 0;
712 wbc.encountered_congestion = 0;
713 wbc.nr_to_write = MAX_WRITEBACK_PAGES;
714 wbc.pages_skipped = 0;
715 writeback_inodes_wb(wb, &wbc);
716 nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
717 wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write;
718
719 /*
720 * If we ran out of stuff to write, bail unless more_io got set
721 */
722 if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) {
723 if (wbc.more_io && !wbc.for_kupdate)
569 continue; 724 continue;
570 __iget(inode); 725 break;
571 spin_unlock(&inode_lock); 726 }
727 }
728
729 return wrote;
730}
731
732/*
733 * Return the next bdi_work struct that hasn't been processed by this
734 * wb thread yet
735 */
736static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi,
737 struct bdi_writeback *wb)
738{
739 struct bdi_work *work, *ret = NULL;
740
741 rcu_read_lock();
742
743 list_for_each_entry_rcu(work, &bdi->work_list, list) {
744 if (!test_and_clear_bit(wb->nr, &work->seen))
745 continue;
746
747 ret = work;
748 break;
749 }
750
751 rcu_read_unlock();
752 return ret;
753}
754
755static long wb_check_old_data_flush(struct bdi_writeback *wb)
756{
757 unsigned long expired;
758 long nr_pages;
759
760 expired = wb->last_old_flush +
761 msecs_to_jiffies(dirty_writeback_interval * 10);
762 if (time_before(jiffies, expired))
763 return 0;
764
765 wb->last_old_flush = jiffies;
766 nr_pages = global_page_state(NR_FILE_DIRTY) +
767 global_page_state(NR_UNSTABLE_NFS) +
768 (inodes_stat.nr_inodes - inodes_stat.nr_unused);
769
770 if (nr_pages)
771 return wb_writeback(wb, nr_pages, NULL, WB_SYNC_NONE, 1);
772
773 return 0;
774}
775
776/*
777 * Retrieve work items and do the writeback they describe
778 */
779long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
780{
781 struct backing_dev_info *bdi = wb->bdi;
782 struct bdi_work *work;
783 long nr_pages, wrote = 0;
784
785 while ((work = get_next_work_item(bdi, wb)) != NULL) {
786 enum writeback_sync_modes sync_mode;
787
788 nr_pages = work->nr_pages;
789
790 /*
791 * Override sync mode, in case we must wait for completion
792 */
793 if (force_wait)
794 work->sync_mode = sync_mode = WB_SYNC_ALL;
795 else
796 sync_mode = work->sync_mode;
797
798 /*
799 * If this isn't a data integrity operation, just notify
800 * that we have seen this work and we are now starting it.
801 */
802 if (sync_mode == WB_SYNC_NONE)
803 wb_clear_pending(wb, work);
804
805 wrote += wb_writeback(wb, nr_pages, work->sb, sync_mode, 0);
806
807 /*
808 * This is a data integrity writeback, so only do the
809 * notification when we have completed the work.
810 */
811 if (sync_mode == WB_SYNC_ALL)
812 wb_clear_pending(wb, work);
813 }
814
815 /*
816 * Check for periodic writeback, kupdated() style
817 */
818 wrote += wb_check_old_data_flush(wb);
819
820 return wrote;
821}
822
823/*
824 * Handle writeback of dirty data for the device backed by this bdi. Also
825 * wakes up periodically and does kupdated style flushing.
826 */
827int bdi_writeback_task(struct bdi_writeback *wb)
828{
829 unsigned long last_active = jiffies;
830 unsigned long wait_jiffies = -1UL;
831 long pages_written;
832
833 while (!kthread_should_stop()) {
834 pages_written = wb_do_writeback(wb, 0);
835
836 if (pages_written)
837 last_active = jiffies;
838 else if (wait_jiffies != -1UL) {
839 unsigned long max_idle;
840
572 /* 841 /*
573 * We hold a reference to 'inode' so it couldn't have 842 * Longest period of inactivity that we tolerate. If we
574 * been removed from s_inodes list while we dropped the 843 * see dirty data again later, the task will get
575 * inode_lock. We cannot iput the inode now as we can 844 * recreated automatically.
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 */ 845 */
580 iput(old_inode); 846 max_idle = max(5UL * 60 * HZ, wait_jiffies);
581 old_inode = inode; 847 if (time_after(jiffies, max_idle + last_active))
848 break;
849 }
582 850
583 filemap_fdatawait(mapping); 851 wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10);
852 set_current_state(TASK_INTERRUPTIBLE);
853 schedule_timeout(wait_jiffies);
854 try_to_freeze();
855 }
584 856
585 cond_resched(); 857 return 0;
858}
859
860/*
861 * Schedule writeback for all backing devices. Expensive! If this is a data
862 * integrity operation, writeback will be complete when this returns. If
863 * we are simply called for WB_SYNC_NONE, then writeback will merely be
864 * scheduled to run.
865 */
866static void bdi_writeback_all(struct writeback_control *wbc)
867{
868 const bool must_wait = wbc->sync_mode == WB_SYNC_ALL;
869 struct backing_dev_info *bdi;
870 struct bdi_work *work;
871 LIST_HEAD(list);
872
873restart:
874 spin_lock(&bdi_lock);
875
876 list_for_each_entry(bdi, &bdi_list, bdi_list) {
877 struct bdi_work *work;
586 878
587 spin_lock(&inode_lock); 879 if (!bdi_has_dirty_io(bdi))
880 continue;
881
882 /*
883 * If work allocation fails, do the writes inline. We drop
884 * the lock and restart the list writeout. This should be OK,
885 * since this happens rarely and because the writeout should
886 * eventually make more free memory available.
887 */
888 work = bdi_alloc_work(wbc);
889 if (!work) {
890 struct writeback_control __wbc;
891
892 /*
893 * Not a data integrity writeout, just continue
894 */
895 if (!must_wait)
896 continue;
897
898 spin_unlock(&bdi_lock);
899 __wbc = *wbc;
900 __wbc.bdi = bdi;
901 writeback_inodes_wbc(&__wbc);
902 goto restart;
588 } 903 }
589 spin_unlock(&inode_lock); 904 if (must_wait)
590 iput(old_inode); 905 list_add_tail(&work->wait_list, &list);
591 } else 906
592 spin_unlock(&inode_lock); 907 bdi_queue_work(bdi, work);
908 }
909
910 spin_unlock(&bdi_lock);
593 911
594 return; /* Leave any unwritten inodes on s_io */ 912 /*
913 * If this is for WB_SYNC_ALL, wait for pending work to complete
914 * before returning.
915 */
916 while (!list_empty(&list)) {
917 work = list_entry(list.next, struct bdi_work, wait_list);
918 list_del(&work->wait_list);
919 bdi_wait_on_work_clear(work);
920 call_rcu(&work->rcu_head, bdi_work_free);
921 }
595} 922}
596EXPORT_SYMBOL_GPL(generic_sync_sb_inodes);
597 923
598static void sync_sb_inodes(struct super_block *sb, 924/*
599 struct writeback_control *wbc) 925 * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back
926 * the whole world.
927 */
928void wakeup_flusher_threads(long nr_pages)
600{ 929{
601 generic_sync_sb_inodes(sb, wbc); 930 struct writeback_control wbc = {
931 .sync_mode = WB_SYNC_NONE,
932 .older_than_this = NULL,
933 .range_cyclic = 1,
934 };
935
936 if (nr_pages == 0)
937 nr_pages = global_page_state(NR_FILE_DIRTY) +
938 global_page_state(NR_UNSTABLE_NFS);
939 wbc.nr_to_write = nr_pages;
940 bdi_writeback_all(&wbc);
602} 941}
603 942
604/* 943static noinline void block_dump___mark_inode_dirty(struct inode *inode)
605 * Start writeback of dirty pagecache data against all unlocked inodes. 944{
945 if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) {
946 struct dentry *dentry;
947 const char *name = "?";
948
949 dentry = d_find_alias(inode);
950 if (dentry) {
951 spin_lock(&dentry->d_lock);
952 name = (const char *) dentry->d_name.name;
953 }
954 printk(KERN_DEBUG
955 "%s(%d): dirtied inode %lu (%s) on %s\n",
956 current->comm, task_pid_nr(current), inode->i_ino,
957 name, inode->i_sb->s_id);
958 if (dentry) {
959 spin_unlock(&dentry->d_lock);
960 dput(dentry);
961 }
962 }
963}
964
965/**
966 * __mark_inode_dirty - internal function
967 * @inode: inode to mark
968 * @flags: what kind of dirty (i.e. I_DIRTY_SYNC)
969 * Mark an inode as dirty. Callers should use mark_inode_dirty or
970 * mark_inode_dirty_sync.
606 * 971 *
607 * Note: 972 * Put the inode on the super block's dirty list.
608 * We don't need to grab a reference to superblock here. If it has non-empty 973 *
609 * ->s_dirty it's hadn't been killed yet and kill_super() won't proceed 974 * CAREFUL! We mark it dirty unconditionally, but move it onto the
610 * past sync_inodes_sb() until the ->s_dirty/s_io/s_more_io lists are all 975 * dirty list only if it is hashed or if it refers to a blockdev.
611 * empty. Since __sync_single_inode() regains inode_lock before it finally moves 976 * If it was not hashed, it will never be added to the dirty list
612 * inode from superblock lists we are OK. 977 * even if it is later hashed, as it will have been marked dirty already.
613 * 978 *
614 * If `older_than_this' is non-zero then only flush inodes which have a 979 * In short, make sure you hash any inodes _before_ you start marking
615 * flushtime older than *older_than_this. 980 * them dirty.
616 * 981 *
617 * If `bdi' is non-zero then we will scan the first inode against each 982 * This function *must* be atomic for the I_DIRTY_PAGES case -
618 * superblock until we find the matching ones. One group will be the dirty 983 * set_page_dirty() is called under spinlock in several places.
619 * inodes against a filesystem. Then when we hit the dummy blockdev superblock, 984 *
620 * sync_sb_inodes will seekout the blockdev which matches `bdi'. Maybe not 985 * Note that for blockdevs, inode->dirtied_when represents the dirtying time of
621 * super-efficient but we're about to do a ton of I/O... 986 * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of
987 * the kernel-internal blockdev inode represents the dirtying time of the
988 * blockdev's pages. This is why for I_DIRTY_PAGES we always use
989 * page->mapping->host, so the page-dirtying time is recorded in the internal
990 * blockdev inode.
622 */ 991 */
623void 992void __mark_inode_dirty(struct inode *inode, int flags)
624writeback_inodes(struct writeback_control *wbc)
625{ 993{
626 struct super_block *sb; 994 struct super_block *sb = inode->i_sb;
627 995
628 might_sleep(); 996 /*
629 spin_lock(&sb_lock); 997 * Don't do this for I_DIRTY_PAGES - that doesn't actually
630restart: 998 * dirty the inode itself
631 list_for_each_entry_reverse(sb, &super_blocks, s_list) { 999 */
632 if (sb_has_dirty_inodes(sb)) { 1000 if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
633 /* we're making our own get_super here */ 1001 if (sb->s_op->dirty_inode)
634 sb->s_count++; 1002 sb->s_op->dirty_inode(inode);
635 spin_unlock(&sb_lock); 1003 }
636 /* 1004
637 * If we can't get the readlock, there's no sense in 1005 /*
638 * waiting around, most of the time the FS is going to 1006 * make sure that changes are seen by all cpus before we test i_state
639 * be unmounted by the time it is released. 1007 * -- mikulas
640 */ 1008 */
641 if (down_read_trylock(&sb->s_umount)) { 1009 smp_mb();
642 if (sb->s_root) 1010
643 sync_sb_inodes(sb, wbc); 1011 /* avoid the locking if we can */
644 up_read(&sb->s_umount); 1012 if ((inode->i_state & flags) == flags)
1013 return;
1014
1015 if (unlikely(block_dump))
1016 block_dump___mark_inode_dirty(inode);
1017
1018 spin_lock(&inode_lock);
1019 if ((inode->i_state & flags) != flags) {
1020 const int was_dirty = inode->i_state & I_DIRTY;
1021
1022 inode->i_state |= flags;
1023
1024 /*
1025 * If the inode is being synced, just update its dirty state.
1026 * The unlocker will place the inode on the appropriate
1027 * superblock list, based upon its state.
1028 */
1029 if (inode->i_state & I_SYNC)
1030 goto out;
1031
1032 /*
1033 * Only add valid (hashed) inodes to the superblock's
1034 * dirty list. Add blockdev inodes as well.
1035 */
1036 if (!S_ISBLK(inode->i_mode)) {
1037 if (hlist_unhashed(&inode->i_hash))
1038 goto out;
1039 }
1040 if (inode->i_state & (I_FREEING|I_CLEAR))
1041 goto out;
1042
1043 /*
1044 * If the inode was already on b_dirty/b_io/b_more_io, don't
1045 * reposition it (that would break b_dirty time-ordering).
1046 */
1047 if (!was_dirty) {
1048 struct bdi_writeback *wb = &inode_to_bdi(inode)->wb;
1049 struct backing_dev_info *bdi = wb->bdi;
1050
1051 if (bdi_cap_writeback_dirty(bdi) &&
1052 !test_bit(BDI_registered, &bdi->state)) {
1053 WARN_ON(1);
1054 printk(KERN_ERR "bdi-%s not registered\n",
1055 bdi->name);
645 } 1056 }
646 spin_lock(&sb_lock); 1057
647 if (__put_super_and_need_restart(sb)) 1058 inode->dirtied_when = jiffies;
648 goto restart; 1059 list_move(&inode->i_list, &wb->b_dirty);
649 } 1060 }
650 if (wbc->nr_to_write <= 0)
651 break;
652 } 1061 }
653 spin_unlock(&sb_lock); 1062out:
1063 spin_unlock(&inode_lock);
654} 1064}
1065EXPORT_SYMBOL(__mark_inode_dirty);
655 1066
656/* 1067/*
657 * writeback and wait upon the filesystem's dirty inodes. The caller will 1068 * Write out a superblock's list of dirty inodes. A wait will be performed
658 * do this in two passes - one to write, and one to wait. 1069 * upon no inodes, all inodes or the final one, depending upon sync_mode.
1070 *
1071 * If older_than_this is non-NULL, then only write out inodes which
1072 * had their first dirtying at a time earlier than *older_than_this.
659 * 1073 *
660 * A finite limit is set on the number of pages which will be written. 1074 * If we're a pdlfush thread, then implement pdflush collision avoidance
661 * To prevent infinite livelock of sys_sync(). 1075 * against the entire list.
662 * 1076 *
663 * We add in the number of potentially dirty inodes, because each inode write 1077 * If `bdi' is non-zero then we're being asked to writeback a specific queue.
664 * can dirty pagecache in the underlying blockdev. 1078 * This function assumes that the blockdev superblock's inodes are backed by
1079 * a variety of queues, so all inodes are searched. For other superblocks,
1080 * assume that all inodes are backed by the same queue.
1081 *
1082 * The inodes to be written are parked on bdi->b_io. They are moved back onto
1083 * bdi->b_dirty as they are selected for writing. This way, none can be missed
1084 * on the writer throttling path, and we get decent balancing between many
1085 * throttled threads: we don't want them all piling up on inode_sync_wait.
665 */ 1086 */
666void sync_inodes_sb(struct super_block *sb, int wait) 1087static void wait_sb_inodes(struct writeback_control *wbc)
1088{
1089 struct inode *inode, *old_inode = NULL;
1090
1091 /*
1092 * We need to be protected against the filesystem going from
1093 * r/o to r/w or vice versa.
1094 */
1095 WARN_ON(!rwsem_is_locked(&wbc->sb->s_umount));
1096
1097 spin_lock(&inode_lock);
1098
1099 /*
1100 * Data integrity sync. Must wait for all pages under writeback,
1101 * because there may have been pages dirtied before our sync
1102 * call, but which had writeout started before we write it out.
1103 * In which case, the inode may not be on the dirty list, but
1104 * we still have to wait for that writeout.
1105 */
1106 list_for_each_entry(inode, &wbc->sb->s_inodes, i_sb_list) {
1107 struct address_space *mapping;
1108
1109 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
1110 continue;
1111 mapping = inode->i_mapping;
1112 if (mapping->nrpages == 0)
1113 continue;
1114 __iget(inode);
1115 spin_unlock(&inode_lock);
1116 /*
1117 * We hold a reference to 'inode' so it couldn't have
1118 * been removed from s_inodes list while we dropped the
1119 * inode_lock. We cannot iput the inode now as we can
1120 * be holding the last reference and we cannot iput it
1121 * under inode_lock. So we keep the reference and iput
1122 * it later.
1123 */
1124 iput(old_inode);
1125 old_inode = inode;
1126
1127 filemap_fdatawait(mapping);
1128
1129 cond_resched();
1130
1131 spin_lock(&inode_lock);
1132 }
1133 spin_unlock(&inode_lock);
1134 iput(old_inode);
1135}
1136
1137/**
1138 * writeback_inodes_sb - writeback dirty inodes from given super_block
1139 * @sb: the superblock
1140 *
1141 * Start writeback on some inodes on this super_block. No guarantees are made
1142 * on how many (if any) will be written, and this function does not wait
1143 * for IO completion of submitted IO. The number of pages submitted is
1144 * returned.
1145 */
1146long writeback_inodes_sb(struct super_block *sb)
667{ 1147{
668 struct writeback_control wbc = { 1148 struct writeback_control wbc = {
669 .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_NONE, 1149 .sb = sb,
1150 .sync_mode = WB_SYNC_NONE,
670 .range_start = 0, 1151 .range_start = 0,
671 .range_end = LLONG_MAX, 1152 .range_end = LLONG_MAX,
672 }; 1153 };
1154 unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY);
1155 unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS);
1156 long nr_to_write;
673 1157
674 if (!wait) { 1158 nr_to_write = nr_dirty + nr_unstable +
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); 1159 (inodes_stat.nr_inodes - inodes_stat.nr_unused);
680 } else
681 wbc.nr_to_write = LONG_MAX; /* doesn't actually matter */
682 1160
683 sync_sb_inodes(sb, &wbc); 1161 wbc.nr_to_write = nr_to_write;
1162 bdi_writeback_all(&wbc);
1163 return nr_to_write - wbc.nr_to_write;
1164}
1165EXPORT_SYMBOL(writeback_inodes_sb);
1166
1167/**
1168 * sync_inodes_sb - sync sb inode pages
1169 * @sb: the superblock
1170 *
1171 * This function writes and waits on any dirty inode belonging to this
1172 * super_block. The number of pages synced is returned.
1173 */
1174long sync_inodes_sb(struct super_block *sb)
1175{
1176 struct writeback_control wbc = {
1177 .sb = sb,
1178 .sync_mode = WB_SYNC_ALL,
1179 .range_start = 0,
1180 .range_end = LLONG_MAX,
1181 };
1182 long nr_to_write = LONG_MAX; /* doesn't actually matter */
1183
1184 wbc.nr_to_write = nr_to_write;
1185 bdi_writeback_all(&wbc);
1186 wait_sb_inodes(&wbc);
1187 return nr_to_write - wbc.nr_to_write;
684} 1188}
1189EXPORT_SYMBOL(sync_inodes_sb);
685 1190
686/** 1191/**
687 * write_inode_now - write an inode to disk 1192 * write_inode_now - write an inode to disk
generated by cgit v1.2.2 (git 2.25.0) at 2025-12-03 22:07:15 -0500