1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
4 * Copyright (c) 2008 Dave Chinner
5 * All Rights Reserved.
6 */
7 #include "xfs.h"
8 #include "xfs_fs.h"
9 #include "xfs_shared.h"
10 #include "xfs_format.h"
11 #include "xfs_log_format.h"
12 #include "xfs_trans_resv.h"
13 #include "xfs_mount.h"
14 #include "xfs_trans.h"
15 #include "xfs_trans_priv.h"
16 #include "xfs_trace.h"
17 #include "xfs_errortag.h"
18 #include "xfs_error.h"
19 #include "xfs_log.h"
20
21 #ifdef DEBUG
22 /*
23 * Check that the list is sorted as it should be.
24 *
25 * Called with the ail lock held, but we don't want to assert fail with it
26 * held otherwise we'll lock everything up and won't be able to debug the
27 * cause. Hence we sample and check the state under the AIL lock and return if
28 * everything is fine, otherwise we drop the lock and run the ASSERT checks.
29 * Asserts may not be fatal, so pick the lock back up and continue onwards.
30 */
31 STATIC void
32 xfs_ail_check(
33 struct xfs_ail *ailp,
34 struct xfs_log_item *lip)
35 {
36 struct xfs_log_item *prev_lip;
37 struct xfs_log_item *next_lip;
38 xfs_lsn_t prev_lsn = NULLCOMMITLSN;
39 xfs_lsn_t next_lsn = NULLCOMMITLSN;
40 xfs_lsn_t lsn;
41 bool in_ail;
42
43
44 if (list_empty(&ailp->ail_head))
45 return;
46
47 /*
48 * Sample then check the next and previous entries are valid.
49 */
50 in_ail = test_bit(XFS_LI_IN_AIL, &lip->li_flags);
51 prev_lip = list_entry(lip->li_ail.prev, struct xfs_log_item, li_ail);
52 if (&prev_lip->li_ail != &ailp->ail_head)
53 prev_lsn = prev_lip->li_lsn;
54 next_lip = list_entry(lip->li_ail.next, struct xfs_log_item, li_ail);
55 if (&next_lip->li_ail != &ailp->ail_head)
56 next_lsn = next_lip->li_lsn;
57 lsn = lip->li_lsn;
58
59 if (in_ail &&
60 (prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0) &&
61 (next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0))
62 return;
63
64 spin_unlock(&ailp->ail_lock);
65 ASSERT(in_ail);
66 ASSERT(prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0);
67 ASSERT(next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0);
68 spin_lock(&ailp->ail_lock);
69 }
70 #else /* !DEBUG */
71 #define xfs_ail_check(a,l)
72 #endif /* DEBUG */
73
74 /*
75 * Return a pointer to the last item in the AIL. If the AIL is empty, then
76 * return NULL.
77 */
78 static struct xfs_log_item *
79 xfs_ail_max(
80 struct xfs_ail *ailp)
81 {
82 if (list_empty(&ailp->ail_head))
83 return NULL;
84
85 return list_entry(ailp->ail_head.prev, struct xfs_log_item, li_ail);
86 }
87
88 /*
89 * Return a pointer to the item which follows the given item in the AIL. If
90 * the given item is the last item in the list, then return NULL.
91 */
92 static struct xfs_log_item *
93 xfs_ail_next(
94 struct xfs_ail *ailp,
95 struct xfs_log_item *lip)
96 {
97 if (lip->li_ail.next == &ailp->ail_head)
98 return NULL;
99
100 return list_first_entry(&lip->li_ail, struct xfs_log_item, li_ail);
101 }
102
103 /*
104 * This is called by the log manager code to determine the LSN of the tail of
105 * the log. This is exactly the LSN of the first item in the AIL. If the AIL
106 * is empty, then this function returns 0.
107 *
108 * We need the AIL lock in order to get a coherent read of the lsn of the last
109 * item in the AIL.
110 */
111 xfs_lsn_t
112 xfs_ail_min_lsn(
113 struct xfs_ail *ailp)
114 {
115 xfs_lsn_t lsn = 0;
116 struct xfs_log_item *lip;
117
118 spin_lock(&ailp->ail_lock);
119 lip = xfs_ail_min(ailp);
120 if (lip)
121 lsn = lip->li_lsn;
122 spin_unlock(&ailp->ail_lock);
123
124 return lsn;
125 }
126
127 /*
128 * Return the maximum lsn held in the AIL, or zero if the AIL is empty.
129 */
130 static xfs_lsn_t
131 xfs_ail_max_lsn(
132 struct xfs_ail *ailp)
133 {
134 xfs_lsn_t lsn = 0;
135 struct xfs_log_item *lip;
136
137 spin_lock(&ailp->ail_lock);
138 lip = xfs_ail_max(ailp);
139 if (lip)
140 lsn = lip->li_lsn;
141 spin_unlock(&ailp->ail_lock);
142
143 return lsn;
144 }
145
146 /*
147 * The cursor keeps track of where our current traversal is up to by tracking
148 * the next item in the list for us. However, for this to be safe, removing an
149 * object from the AIL needs to invalidate any cursor that points to it. hence
150 * the traversal cursor needs to be linked to the struct xfs_ail so that
151 * deletion can search all the active cursors for invalidation.
152 */
153 STATIC void
154 xfs_trans_ail_cursor_init(
155 struct xfs_ail *ailp,
156 struct xfs_ail_cursor *cur)
157 {
158 cur->item = NULL;
159 list_add_tail(&cur->list, &ailp->ail_cursors);
160 }
161
162 /*
163 * Get the next item in the traversal and advance the cursor. If the cursor
164 * was invalidated (indicated by a lip of 1), restart the traversal.
165 */
166 struct xfs_log_item *
167 xfs_trans_ail_cursor_next(
168 struct xfs_ail *ailp,
169 struct xfs_ail_cursor *cur)
170 {
171 struct xfs_log_item *lip = cur->item;
172
173 if ((uintptr_t)lip & 1)
174 lip = xfs_ail_min(ailp);
175 if (lip)
176 cur->item = xfs_ail_next(ailp, lip);
177 return lip;
178 }
179
180 /*
181 * When the traversal is complete, we need to remove the cursor from the list
182 * of traversing cursors.
183 */
184 void
185 xfs_trans_ail_cursor_done(
186 struct xfs_ail_cursor *cur)
187 {
188 cur->item = NULL;
189 list_del_init(&cur->list);
190 }
191
192 /*
193 * Invalidate any cursor that is pointing to this item. This is called when an
194 * item is removed from the AIL. Any cursor pointing to this object is now
195 * invalid and the traversal needs to be terminated so it doesn't reference a
196 * freed object. We set the low bit of the cursor item pointer so we can
197 * distinguish between an invalidation and the end of the list when getting the
198 * next item from the cursor.
199 */
200 STATIC void
201 xfs_trans_ail_cursor_clear(
202 struct xfs_ail *ailp,
203 struct xfs_log_item *lip)
204 {
205 struct xfs_ail_cursor *cur;
206
207 list_for_each_entry(cur, &ailp->ail_cursors, list) {
208 if (cur->item == lip)
209 cur->item = (struct xfs_log_item *)
210 ((uintptr_t)cur->item | 1);
211 }
212 }
213
214 /*
215 * Find the first item in the AIL with the given @lsn by searching in ascending
216 * LSN order and initialise the cursor to point to the next item for a
217 * ascending traversal. Pass a @lsn of zero to initialise the cursor to the
218 * first item in the AIL. Returns NULL if the list is empty.
219 */
220 struct xfs_log_item *
221 xfs_trans_ail_cursor_first(
222 struct xfs_ail *ailp,
223 struct xfs_ail_cursor *cur,
224 xfs_lsn_t lsn)
225 {
226 struct xfs_log_item *lip;
227
228 xfs_trans_ail_cursor_init(ailp, cur);
229
230 if (lsn == 0) {
231 lip = xfs_ail_min(ailp);
232 goto out;
233 }
234
235 list_for_each_entry(lip, &ailp->ail_head, li_ail) {
236 if (XFS_LSN_CMP(lip->li_lsn, lsn) >= 0)
237 goto out;
238 }
239 return NULL;
240
241 out:
242 if (lip)
243 cur->item = xfs_ail_next(ailp, lip);
244 return lip;
245 }
246
247 static struct xfs_log_item *
248 __xfs_trans_ail_cursor_last(
249 struct xfs_ail *ailp,
250 xfs_lsn_t lsn)
251 {
252 struct xfs_log_item *lip;
253
254 list_for_each_entry_reverse(lip, &ailp->ail_head, li_ail) {
255 if (XFS_LSN_CMP(lip->li_lsn, lsn) <= 0)
256 return lip;
257 }
258 return NULL;
259 }
260
261 /*
262 * Find the last item in the AIL with the given @lsn by searching in descending
263 * LSN order and initialise the cursor to point to that item. If there is no
264 * item with the value of @lsn, then it sets the cursor to the last item with an
265 * LSN lower than @lsn. Returns NULL if the list is empty.
266 */
267 struct xfs_log_item *
268 xfs_trans_ail_cursor_last(
269 struct xfs_ail *ailp,
270 struct xfs_ail_cursor *cur,
271 xfs_lsn_t lsn)
272 {
273 xfs_trans_ail_cursor_init(ailp, cur);
274 cur->item = __xfs_trans_ail_cursor_last(ailp, lsn);
275 return cur->item;
276 }
277
278 /*
279 * Splice the log item list into the AIL at the given LSN. We splice to the
280 * tail of the given LSN to maintain insert order for push traversals. The
281 * cursor is optional, allowing repeated updates to the same LSN to avoid
282 * repeated traversals. This should not be called with an empty list.
283 */
284 static void
285 xfs_ail_splice(
286 struct xfs_ail *ailp,
287 struct xfs_ail_cursor *cur,
288 struct list_head *list,
289 xfs_lsn_t lsn)
290 {
291 struct xfs_log_item *lip;
292
293 ASSERT(!list_empty(list));
294
295 /*
296 * Use the cursor to determine the insertion point if one is
297 * provided. If not, or if the one we got is not valid,
298 * find the place in the AIL where the items belong.
299 */
300 lip = cur ? cur->item : NULL;
301 if (!lip || (uintptr_t)lip & 1)
302 lip = __xfs_trans_ail_cursor_last(ailp, lsn);
303
304 /*
305 * If a cursor is provided, we know we're processing the AIL
306 * in lsn order, and future items to be spliced in will
307 * follow the last one being inserted now. Update the
308 * cursor to point to that last item, now while we have a
309 * reliable pointer to it.
310 */
311 if (cur)
312 cur->item = list_entry(list->prev, struct xfs_log_item, li_ail);
313
314 /*
315 * Finally perform the splice. Unless the AIL was empty,
316 * lip points to the item in the AIL _after_ which the new
317 * items should go. If lip is null the AIL was empty, so
318 * the new items go at the head of the AIL.
319 */
320 if (lip)
321 list_splice(list, &lip->li_ail);
322 else
323 list_splice(list, &ailp->ail_head);
324 }
325
326 /*
327 * Delete the given item from the AIL. Return a pointer to the item.
328 */
329 static void
330 xfs_ail_delete(
331 struct xfs_ail *ailp,
332 struct xfs_log_item *lip)
333 {
334 xfs_ail_check(ailp, lip);
335 list_del(&lip->li_ail);
336 xfs_trans_ail_cursor_clear(ailp, lip);
337 }
338
339 static inline uint
340 xfsaild_push_item(
341 struct xfs_ail *ailp,
342 struct xfs_log_item *lip)
343 {
344 /*
345 * If log item pinning is enabled, skip the push and track the item as
346 * pinned. This can help induce head-behind-tail conditions.
347 */
348 if (XFS_TEST_ERROR(false, ailp->ail_mount, XFS_ERRTAG_LOG_ITEM_PIN))
349 return XFS_ITEM_PINNED;
350
351 /*
352 * Consider the item pinned if a push callback is not defined so the
353 * caller will force the log. This should only happen for intent items
354 * as they are unpinned once the associated done item is committed to
355 * the on-disk log.
356 */
357 if (!lip->li_ops->iop_push)
358 return XFS_ITEM_PINNED;
359 return lip->li_ops->iop_push(lip, &ailp->ail_buf_list);
360 }
361
362 static long
363 xfsaild_push(
364 struct xfs_ail *ailp)
365 {
366 xfs_mount_t *mp = ailp->ail_mount;
367 struct xfs_ail_cursor cur;
368 struct xfs_log_item *lip;
369 xfs_lsn_t lsn;
370 xfs_lsn_t target;
371 long tout;
372 int stuck = 0;
373 int flushing = 0;
374 int count = 0;
375
376 /*
377 * If we encountered pinned items or did not finish writing out all
378 * buffers the last time we ran, force the log first and wait for it
379 * before pushing again.
380 */
381 if (ailp->ail_log_flush && ailp->ail_last_pushed_lsn == 0 &&
382 (!list_empty_careful(&ailp->ail_buf_list) ||
383 xfs_ail_min_lsn(ailp))) {
384 ailp->ail_log_flush = 0;
385
386 XFS_STATS_INC(mp, xs_push_ail_flush);
387 xfs_log_force(mp, XFS_LOG_SYNC);
388 }
389
390 spin_lock(&ailp->ail_lock);
391
392 /* barrier matches the ail_target update in xfs_ail_push() */
393 smp_rmb();
394 target = ailp->ail_target;
395 ailp->ail_target_prev = target;
396
397 lip = xfs_trans_ail_cursor_first(ailp, &cur, ailp->ail_last_pushed_lsn);
398 if (!lip) {
399 /*
400 * If the AIL is empty or our push has reached the end we are
401 * done now.
402 */
403 xfs_trans_ail_cursor_done(&cur);
404 spin_unlock(&ailp->ail_lock);
405 goto out_done;
406 }
407
408 XFS_STATS_INC(mp, xs_push_ail);
409
410 lsn = lip->li_lsn;
411 while ((XFS_LSN_CMP(lip->li_lsn, target) <= 0)) {
412 int lock_result;
413
414 /*
415 * Note that iop_push may unlock and reacquire the AIL lock. We
416 * rely on the AIL cursor implementation to be able to deal with
417 * the dropped lock.
418 */
419 lock_result = xfsaild_push_item(ailp, lip);
420 switch (lock_result) {
421 case XFS_ITEM_SUCCESS:
422 XFS_STATS_INC(mp, xs_push_ail_success);
423 trace_xfs_ail_push(lip);
424
425 ailp->ail_last_pushed_lsn = lsn;
426 break;
427
428 case XFS_ITEM_FLUSHING:
429 /*
430 * The item or its backing buffer is already beeing
431 * flushed. The typical reason for that is that an
432 * inode buffer is locked because we already pushed the
433 * updates to it as part of inode clustering.
434 *
435 * We do not want to to stop flushing just because lots
436 * of items are already beeing flushed, but we need to
437 * re-try the flushing relatively soon if most of the
438 * AIL is beeing flushed.
439 */
440 XFS_STATS_INC(mp, xs_push_ail_flushing);
441 trace_xfs_ail_flushing(lip);
442
443 flushing++;
444 ailp->ail_last_pushed_lsn = lsn;
445 break;
446
447 case XFS_ITEM_PINNED:
448 XFS_STATS_INC(mp, xs_push_ail_pinned);
449 trace_xfs_ail_pinned(lip);
450
451 stuck++;
452 ailp->ail_log_flush++;
453 break;
454 case XFS_ITEM_LOCKED:
455 XFS_STATS_INC(mp, xs_push_ail_locked);
456 trace_xfs_ail_locked(lip);
457
458 stuck++;
459 break;
460 default:
461 ASSERT(0);
462 break;
463 }
464
465 count++;
466
467 /*
468 * Are there too many items we can't do anything with?
469 *
470 * If we we are skipping too many items because we can't flush
471 * them or they are already being flushed, we back off and
472 * given them time to complete whatever operation is being
473 * done. i.e. remove pressure from the AIL while we can't make
474 * progress so traversals don't slow down further inserts and
475 * removals to/from the AIL.
476 *
477 * The value of 100 is an arbitrary magic number based on
478 * observation.
479 */
480 if (stuck > 100)
481 break;
482
483 lip = xfs_trans_ail_cursor_next(ailp, &cur);
484 if (lip == NULL)
485 break;
486 lsn = lip->li_lsn;
487 }
488 xfs_trans_ail_cursor_done(&cur);
489 spin_unlock(&ailp->ail_lock);
490
491 if (xfs_buf_delwri_submit_nowait(&ailp->ail_buf_list))
492 ailp->ail_log_flush++;
493
494 if (!count || XFS_LSN_CMP(lsn, target) >= 0) {
495 out_done:
496 /*
497 * We reached the target or the AIL is empty, so wait a bit
498 * longer for I/O to complete and remove pushed items from the
499 * AIL before we start the next scan from the start of the AIL.
500 */
501 tout = 50;
502 ailp->ail_last_pushed_lsn = 0;
503 } else if (((stuck + flushing) * 100) / count > 90) {
504 /*
505 * Either there is a lot of contention on the AIL or we are
506 * stuck due to operations in progress. "Stuck" in this case
507 * is defined as >90% of the items we tried to push were stuck.
508 *
509 * Backoff a bit more to allow some I/O to complete before
510 * restarting from the start of the AIL. This prevents us from
511 * spinning on the same items, and if they are pinned will all
512 * the restart to issue a log force to unpin the stuck items.
513 */
514 tout = 20;
515 ailp->ail_last_pushed_lsn = 0;
516 } else {
517 /*
518 * Assume we have more work to do in a short while.
519 */
520 tout = 10;
521 }
522
523 return tout;
524 }
525
526 static int
527 xfsaild(
528 void *data)
529 {
530 struct xfs_ail *ailp = data;
531 long tout = 0; /* milliseconds */
532 unsigned int noreclaim_flag;
533
534 noreclaim_flag = memalloc_noreclaim_save();
535 set_freezable();
536
537 while (1) {
538 if (tout && tout <= 20)
539 set_current_state(TASK_KILLABLE);
540 else
541 set_current_state(TASK_INTERRUPTIBLE);
542
543 /*
544 * Check kthread_should_stop() after we set the task state to
545 * guarantee that we either see the stop bit and exit or the
546 * task state is reset to runnable such that it's not scheduled
547 * out indefinitely and detects the stop bit at next iteration.
548 * A memory barrier is included in above task state set to
549 * serialize again kthread_stop().
550 */
551 if (kthread_should_stop()) {
552 __set_current_state(TASK_RUNNING);
553
554 /*
555 * The caller forces out the AIL before stopping the
556 * thread in the common case, which means the delwri
557 * queue is drained. In the shutdown case, the queue may
558 * still hold relogged buffers that haven't been
559 * submitted because they were pinned since added to the
560 * queue.
561 *
562 * Log I/O error processing stales the underlying buffer
563 * and clears the delwri state, expecting the buf to be
564 * removed on the next submission attempt. That won't
565 * happen if we're shutting down, so this is the last
566 * opportunity to release such buffers from the queue.
567 */
568 ASSERT(list_empty(&ailp->ail_buf_list) ||
569 XFS_FORCED_SHUTDOWN(ailp->ail_mount));
570 xfs_buf_delwri_cancel(&ailp->ail_buf_list);
571 break;
572 }
573
574 spin_lock(&ailp->ail_lock);
575
576 /*
577 * Idle if the AIL is empty and we are not racing with a target
578 * update. We check the AIL after we set the task to a sleep
579 * state to guarantee that we either catch an ail_target update
580 * or that a wake_up resets the state to TASK_RUNNING.
581 * Otherwise, we run the risk of sleeping indefinitely.
582 *
583 * The barrier matches the ail_target update in xfs_ail_push().
584 */
585 smp_rmb();
586 if (!xfs_ail_min(ailp) &&
587 ailp->ail_target == ailp->ail_target_prev) {
588 spin_unlock(&ailp->ail_lock);
589 freezable_schedule();
590 tout = 0;
591 continue;
592 }
593 spin_unlock(&ailp->ail_lock);
594
595 if (tout)
596 freezable_schedule_timeout(msecs_to_jiffies(tout));
597
598 __set_current_state(TASK_RUNNING);
599
600 try_to_freeze();
601
602 tout = xfsaild_push(ailp);
603 }
604
605 memalloc_noreclaim_restore(noreclaim_flag);
606 return 0;
607 }
608
609 /*
610 * This routine is called to move the tail of the AIL forward. It does this by
611 * trying to flush items in the AIL whose lsns are below the given
612 * threshold_lsn.
613 *
614 * The push is run asynchronously in a workqueue, which means the caller needs
615 * to handle waiting on the async flush for space to become available.
616 * We don't want to interrupt any push that is in progress, hence we only queue
617 * work if we set the pushing bit approriately.
618 *
619 * We do this unlocked - we only need to know whether there is anything in the
620 * AIL at the time we are called. We don't need to access the contents of
621 * any of the objects, so the lock is not needed.
622 */
623 void
624 xfs_ail_push(
625 struct xfs_ail *ailp,
626 xfs_lsn_t threshold_lsn)
627 {
628 struct xfs_log_item *lip;
629
630 lip = xfs_ail_min(ailp);
631 if (!lip || XFS_FORCED_SHUTDOWN(ailp->ail_mount) ||
632 XFS_LSN_CMP(threshold_lsn, ailp->ail_target) <= 0)
633 return;
634
635 /*
636 * Ensure that the new target is noticed in push code before it clears
637 * the XFS_AIL_PUSHING_BIT.
638 */
639 smp_wmb();
640 xfs_trans_ail_copy_lsn(ailp, &ailp->ail_target, &threshold_lsn);
641 smp_wmb();
642
643 wake_up_process(ailp->ail_task);
644 }
645
646 /*
647 * Push out all items in the AIL immediately
648 */
649 void
650 xfs_ail_push_all(
651 struct xfs_ail *ailp)
652 {
653 xfs_lsn_t threshold_lsn = xfs_ail_max_lsn(ailp);
654
655 if (threshold_lsn)
656 xfs_ail_push(ailp, threshold_lsn);
657 }
658
659 /*
660 * Push out all items in the AIL immediately and wait until the AIL is empty.
661 */
662 void
663 xfs_ail_push_all_sync(
664 struct xfs_ail *ailp)
665 {
666 struct xfs_log_item *lip;
667 DEFINE_WAIT(wait);
668
669 spin_lock(&ailp->ail_lock);
670 while ((lip = xfs_ail_max(ailp)) != NULL) {
671 prepare_to_wait(&ailp->ail_empty, &wait, TASK_UNINTERRUPTIBLE);
672 ailp->ail_target = lip->li_lsn;
673 wake_up_process(ailp->ail_task);
674 spin_unlock(&ailp->ail_lock);
675 schedule();
676 spin_lock(&ailp->ail_lock);
677 }
678 spin_unlock(&ailp->ail_lock);
679
680 finish_wait(&ailp->ail_empty, &wait);
681 }
682
683 /*
684 * xfs_trans_ail_update - bulk AIL insertion operation.
685 *
686 * @xfs_trans_ail_update takes an array of log items that all need to be
687 * positioned at the same LSN in the AIL. If an item is not in the AIL, it will
688 * be added. Otherwise, it will be repositioned by removing it and re-adding
689 * it to the AIL. If we move the first item in the AIL, update the log tail to
690 * match the new minimum LSN in the AIL.
691 *
692 * This function takes the AIL lock once to execute the update operations on
693 * all the items in the array, and as such should not be called with the AIL
694 * lock held. As a result, once we have the AIL lock, we need to check each log
695 * item LSN to confirm it needs to be moved forward in the AIL.
696 *
697 * To optimise the insert operation, we delete all the items from the AIL in
698 * the first pass, moving them into a temporary list, then splice the temporary
699 * list into the correct position in the AIL. This avoids needing to do an
700 * insert operation on every item.
701 *
702 * This function must be called with the AIL lock held. The lock is dropped
703 * before returning.
704 */
705 void
706 xfs_trans_ail_update_bulk(
707 struct xfs_ail *ailp,
708 struct xfs_ail_cursor *cur,
709 struct xfs_log_item **log_items,
710 int nr_items,
711 xfs_lsn_t lsn) __releases(ailp->ail_lock)
712 {
713 struct xfs_log_item *mlip;
714 int mlip_changed = 0;
715 int i;
716 LIST_HEAD(tmp);
717
718 ASSERT(nr_items > 0); /* Not required, but true. */
719 mlip = xfs_ail_min(ailp);
720
721 for (i = 0; i < nr_items; i++) {
722 struct xfs_log_item *lip = log_items[i];
723 if (test_and_set_bit(XFS_LI_IN_AIL, &lip->li_flags)) {
724 /* check if we really need to move the item */
725 if (XFS_LSN_CMP(lsn, lip->li_lsn) <= 0)
726 continue;
727
728 trace_xfs_ail_move(lip, lip->li_lsn, lsn);
729 xfs_ail_delete(ailp, lip);
730 if (mlip == lip)
731 mlip_changed = 1;
732 } else {
733 trace_xfs_ail_insert(lip, 0, lsn);
734 }
735 lip->li_lsn = lsn;
736 list_add(&lip->li_ail, &tmp);
737 }
738
739 if (!list_empty(&tmp))
740 xfs_ail_splice(ailp, cur, &tmp, lsn);
741
742 if (mlip_changed) {
743 if (!XFS_FORCED_SHUTDOWN(ailp->ail_mount))
744 xlog_assign_tail_lsn_locked(ailp->ail_mount);
745 spin_unlock(&ailp->ail_lock);
746
747 xfs_log_space_wake(ailp->ail_mount);
748 } else {
749 spin_unlock(&ailp->ail_lock);
750 }
751 }
752
753 bool
754 xfs_ail_delete_one(
755 struct xfs_ail *ailp,
756 struct xfs_log_item *lip)
757 {
758 struct xfs_log_item *mlip = xfs_ail_min(ailp);
759
760 trace_xfs_ail_delete(lip, mlip->li_lsn, lip->li_lsn);
761 xfs_ail_delete(ailp, lip);
762 xfs_clear_li_failed(lip);
763 clear_bit(XFS_LI_IN_AIL, &lip->li_flags);
764 lip->li_lsn = 0;
765
766 return mlip == lip;
767 }
768
769 /**
770 * Remove a log items from the AIL
771 *
772 * @xfs_trans_ail_delete_bulk takes an array of log items that all need to
773 * removed from the AIL. The caller is already holding the AIL lock, and done
774 * all the checks necessary to ensure the items passed in via @log_items are
775 * ready for deletion. This includes checking that the items are in the AIL.
776 *
777 * For each log item to be removed, unlink it from the AIL, clear the IN_AIL
778 * flag from the item and reset the item's lsn to 0. If we remove the first
779 * item in the AIL, update the log tail to match the new minimum LSN in the
780 * AIL.
781 *
782 * This function will not drop the AIL lock until all items are removed from
783 * the AIL to minimise the amount of lock traffic on the AIL. This does not
784 * greatly increase the AIL hold time, but does significantly reduce the amount
785 * of traffic on the lock, especially during IO completion.
786 *
787 * This function must be called with the AIL lock held. The lock is dropped
788 * before returning.
789 */
790 void
791 xfs_trans_ail_delete(
792 struct xfs_ail *ailp,
793 struct xfs_log_item *lip,
794 int shutdown_type) __releases(ailp->ail_lock)
795 {
796 struct xfs_mount *mp = ailp->ail_mount;
797 bool mlip_changed;
798
799 if (!test_bit(XFS_LI_IN_AIL, &lip->li_flags)) {
800 spin_unlock(&ailp->ail_lock);
801 if (!XFS_FORCED_SHUTDOWN(mp)) {
802 xfs_alert_tag(mp, XFS_PTAG_AILDELETE,
803 "%s: attempting to delete a log item that is not in the AIL",
804 __func__);
805 xfs_force_shutdown(mp, shutdown_type);
806 }
807 return;
808 }
809
810 mlip_changed = xfs_ail_delete_one(ailp, lip);
811 if (mlip_changed) {
812 if (!XFS_FORCED_SHUTDOWN(mp))
813 xlog_assign_tail_lsn_locked(mp);
814 if (list_empty(&ailp->ail_head))
815 wake_up_all(&ailp->ail_empty);
816 }
817
818 spin_unlock(&ailp->ail_lock);
819 if (mlip_changed)
820 xfs_log_space_wake(ailp->ail_mount);
821 }
822
823 int
824 xfs_trans_ail_init(
825 xfs_mount_t *mp)
826 {
827 struct xfs_ail *ailp;
828
829 ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL);
830 if (!ailp)
831 return -ENOMEM;
832
833 ailp->ail_mount = mp;
834 INIT_LIST_HEAD(&ailp->ail_head);
835 INIT_LIST_HEAD(&ailp->ail_cursors);
836 spin_lock_init(&ailp->ail_lock);
837 INIT_LIST_HEAD(&ailp->ail_buf_list);
838 init_waitqueue_head(&ailp->ail_empty);
839
840 ailp->ail_task = kthread_run(xfsaild, ailp, "xfsaild/%s",
841 ailp->ail_mount->m_fsname);
842 if (IS_ERR(ailp->ail_task))
843 goto out_free_ailp;
844
845 mp->m_ail = ailp;
846 return 0;
847
848 out_free_ailp:
849 kmem_free(ailp);
850 return -ENOMEM;
851 }
852
853 void
854 xfs_trans_ail_destroy(
855 xfs_mount_t *mp)
856 {
857 struct xfs_ail *ailp = mp->m_ail;
858
859 kthread_stop(ailp->ail_task);
860 kmem_free(ailp);
861 }