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xfs: allow assigning the tail lsn with the AIL lock held
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1da177e4 1/*
7b718769 2 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
c7e8f268 3 * Copyright (c) 2008 Dave Chinner
7b718769 4 * All Rights Reserved.
1da177e4 5 *
7b718769
NS
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
1da177e4
LT
8 * published by the Free Software Foundation.
9 *
7b718769
NS
10 * This program is distributed in the hope that it would be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
1da177e4 14 *
7b718769
NS
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
1da177e4 18 */
1da177e4 19#include "xfs.h"
a844f451 20#include "xfs_fs.h"
1da177e4 21#include "xfs_types.h"
1da177e4 22#include "xfs_log.h"
a844f451 23#include "xfs_inum.h"
1da177e4
LT
24#include "xfs_trans.h"
25#include "xfs_sb.h"
da353b0d 26#include "xfs_ag.h"
1da177e4
LT
27#include "xfs_mount.h"
28#include "xfs_trans_priv.h"
9e4c109a 29#include "xfs_trace.h"
1da177e4
LT
30#include "xfs_error.h"
31
1da177e4 32#ifdef DEBUG
cd4a3c50
DC
33/*
34 * Check that the list is sorted as it should be.
35 */
36STATIC void
37xfs_ail_check(
38 struct xfs_ail *ailp,
39 xfs_log_item_t *lip)
40{
41 xfs_log_item_t *prev_lip;
42
43 if (list_empty(&ailp->xa_ail))
44 return;
45
46 /*
47 * Check the next and previous entries are valid.
48 */
49 ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
50 prev_lip = list_entry(lip->li_ail.prev, xfs_log_item_t, li_ail);
51 if (&prev_lip->li_ail != &ailp->xa_ail)
52 ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
53
54 prev_lip = list_entry(lip->li_ail.next, xfs_log_item_t, li_ail);
55 if (&prev_lip->li_ail != &ailp->xa_ail)
56 ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) >= 0);
57
58
59#ifdef XFS_TRANS_DEBUG
60 /*
61 * Walk the list checking lsn ordering, and that every entry has the
62 * XFS_LI_IN_AIL flag set. This is really expensive, so only do it
63 * when specifically debugging the transaction subsystem.
64 */
65 prev_lip = list_entry(&ailp->xa_ail, xfs_log_item_t, li_ail);
66 list_for_each_entry(lip, &ailp->xa_ail, li_ail) {
67 if (&prev_lip->li_ail != &ailp->xa_ail)
68 ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
69 ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
70 prev_lip = lip;
71 }
72#endif /* XFS_TRANS_DEBUG */
73}
74#else /* !DEBUG */
de08dbc1 75#define xfs_ail_check(a,l)
1da177e4
LT
76#endif /* DEBUG */
77
cd4a3c50
DC
78/*
79 * Return a pointer to the first item in the AIL. If the AIL is empty, then
80 * return NULL.
81 */
1c304625 82xfs_log_item_t *
cd4a3c50
DC
83xfs_ail_min(
84 struct xfs_ail *ailp)
85{
86 if (list_empty(&ailp->xa_ail))
87 return NULL;
88
89 return list_first_entry(&ailp->xa_ail, xfs_log_item_t, li_ail);
90}
91
fd074841
DC
92 /*
93 * Return a pointer to the last item in the AIL. If the AIL is empty, then
94 * return NULL.
95 */
96static xfs_log_item_t *
97xfs_ail_max(
98 struct xfs_ail *ailp)
99{
100 if (list_empty(&ailp->xa_ail))
101 return NULL;
102
103 return list_entry(ailp->xa_ail.prev, xfs_log_item_t, li_ail);
104}
105
cd4a3c50
DC
106/*
107 * Return a pointer to the item which follows the given item in the AIL. If
108 * the given item is the last item in the list, then return NULL.
109 */
110static xfs_log_item_t *
111xfs_ail_next(
112 struct xfs_ail *ailp,
113 xfs_log_item_t *lip)
114{
115 if (lip->li_ail.next == &ailp->xa_ail)
116 return NULL;
117
118 return list_first_entry(&lip->li_ail, xfs_log_item_t, li_ail);
119}
1da177e4
LT
120
121/*
cd4a3c50
DC
122 * This is called by the log manager code to determine the LSN of the tail of
123 * the log. This is exactly the LSN of the first item in the AIL. If the AIL
124 * is empty, then this function returns 0.
1da177e4 125 *
cd4a3c50
DC
126 * We need the AIL lock in order to get a coherent read of the lsn of the last
127 * item in the AIL.
1da177e4
LT
128 */
129xfs_lsn_t
fd074841 130xfs_ail_min_lsn(
5b00f14f 131 struct xfs_ail *ailp)
1da177e4 132{
cd4a3c50 133 xfs_lsn_t lsn = 0;
1da177e4 134 xfs_log_item_t *lip;
1da177e4 135
c7e8f268 136 spin_lock(&ailp->xa_lock);
5b00f14f 137 lip = xfs_ail_min(ailp);
cd4a3c50 138 if (lip)
1da177e4 139 lsn = lip->li_lsn;
c7e8f268 140 spin_unlock(&ailp->xa_lock);
1da177e4
LT
141
142 return lsn;
143}
144
fd074841
DC
145/*
146 * Return the maximum lsn held in the AIL, or zero if the AIL is empty.
147 */
148static xfs_lsn_t
149xfs_ail_max_lsn(
150 struct xfs_ail *ailp)
151{
152 xfs_lsn_t lsn = 0;
153 xfs_log_item_t *lip;
154
155 spin_lock(&ailp->xa_lock);
156 lip = xfs_ail_max(ailp);
157 if (lip)
158 lsn = lip->li_lsn;
159 spin_unlock(&ailp->xa_lock);
160
161 return lsn;
162}
163
27d8d5fe 164/*
af3e4022
DC
165 * The cursor keeps track of where our current traversal is up to by tracking
166 * the next item in the list for us. However, for this to be safe, removing an
167 * object from the AIL needs to invalidate any cursor that points to it. hence
168 * the traversal cursor needs to be linked to the struct xfs_ail so that
169 * deletion can search all the active cursors for invalidation.
27d8d5fe 170 */
5b00f14f 171STATIC void
27d8d5fe
DC
172xfs_trans_ail_cursor_init(
173 struct xfs_ail *ailp,
174 struct xfs_ail_cursor *cur)
175{
176 cur->item = NULL;
af3e4022 177 list_add_tail(&cur->list, &ailp->xa_cursors);
27d8d5fe
DC
178}
179
27d8d5fe 180/*
af3e4022
DC
181 * Get the next item in the traversal and advance the cursor. If the cursor
182 * was invalidated (indicated by a lip of 1), restart the traversal.
27d8d5fe 183 */
5b00f14f 184struct xfs_log_item *
27d8d5fe
DC
185xfs_trans_ail_cursor_next(
186 struct xfs_ail *ailp,
187 struct xfs_ail_cursor *cur)
188{
189 struct xfs_log_item *lip = cur->item;
190
191 if ((__psint_t)lip & 1)
192 lip = xfs_ail_min(ailp);
16b59029
DC
193 if (lip)
194 cur->item = xfs_ail_next(ailp, lip);
27d8d5fe
DC
195 return lip;
196}
197
27d8d5fe 198/*
af3e4022
DC
199 * When the traversal is complete, we need to remove the cursor from the list
200 * of traversing cursors.
27d8d5fe
DC
201 */
202void
203xfs_trans_ail_cursor_done(
204 struct xfs_ail *ailp,
af3e4022 205 struct xfs_ail_cursor *cur)
27d8d5fe 206{
af3e4022
DC
207 cur->item = NULL;
208 list_del_init(&cur->list);
27d8d5fe
DC
209}
210
5b00f14f 211/*
af3e4022
DC
212 * Invalidate any cursor that is pointing to this item. This is called when an
213 * item is removed from the AIL. Any cursor pointing to this object is now
214 * invalid and the traversal needs to be terminated so it doesn't reference a
215 * freed object. We set the low bit of the cursor item pointer so we can
216 * distinguish between an invalidation and the end of the list when getting the
217 * next item from the cursor.
5b00f14f
DC
218 */
219STATIC void
220xfs_trans_ail_cursor_clear(
221 struct xfs_ail *ailp,
222 struct xfs_log_item *lip)
223{
224 struct xfs_ail_cursor *cur;
225
af3e4022 226 list_for_each_entry(cur, &ailp->xa_cursors, list) {
5b00f14f
DC
227 if (cur->item == lip)
228 cur->item = (struct xfs_log_item *)
229 ((__psint_t)cur->item | 1);
230 }
231}
232
249a8c11 233/*
16b59029
DC
234 * Find the first item in the AIL with the given @lsn by searching in ascending
235 * LSN order and initialise the cursor to point to the next item for a
236 * ascending traversal. Pass a @lsn of zero to initialise the cursor to the
237 * first item in the AIL. Returns NULL if the list is empty.
249a8c11 238 */
5b00f14f
DC
239xfs_log_item_t *
240xfs_trans_ail_cursor_first(
27d8d5fe
DC
241 struct xfs_ail *ailp,
242 struct xfs_ail_cursor *cur,
243 xfs_lsn_t lsn)
249a8c11 244{
27d8d5fe 245 xfs_log_item_t *lip;
249a8c11 246
5b00f14f 247 xfs_trans_ail_cursor_init(ailp, cur);
16b59029
DC
248
249 if (lsn == 0) {
250 lip = xfs_ail_min(ailp);
5b00f14f 251 goto out;
16b59029 252 }
249a8c11 253
27d8d5fe 254 list_for_each_entry(lip, &ailp->xa_ail, li_ail) {
5b00f14f 255 if (XFS_LSN_CMP(lip->li_lsn, lsn) >= 0)
7ee49acf 256 goto out;
535f6b37 257 }
16b59029
DC
258 return NULL;
259
5b00f14f 260out:
16b59029
DC
261 if (lip)
262 cur->item = xfs_ail_next(ailp, lip);
5b00f14f 263 return lip;
249a8c11
DC
264}
265
1d8c95a3
DC
266static struct xfs_log_item *
267__xfs_trans_ail_cursor_last(
268 struct xfs_ail *ailp,
269 xfs_lsn_t lsn)
270{
271 xfs_log_item_t *lip;
272
273 list_for_each_entry_reverse(lip, &ailp->xa_ail, li_ail) {
274 if (XFS_LSN_CMP(lip->li_lsn, lsn) <= 0)
275 return lip;
276 }
277 return NULL;
278}
279
280/*
16b59029
DC
281 * Find the last item in the AIL with the given @lsn by searching in descending
282 * LSN order and initialise the cursor to point to that item. If there is no
283 * item with the value of @lsn, then it sets the cursor to the last item with an
284 * LSN lower than @lsn. Returns NULL if the list is empty.
1d8c95a3
DC
285 */
286struct xfs_log_item *
287xfs_trans_ail_cursor_last(
288 struct xfs_ail *ailp,
289 struct xfs_ail_cursor *cur,
290 xfs_lsn_t lsn)
291{
292 xfs_trans_ail_cursor_init(ailp, cur);
293 cur->item = __xfs_trans_ail_cursor_last(ailp, lsn);
294 return cur->item;
295}
296
297/*
16b59029 298 * Splice the log item list into the AIL at the given LSN. We splice to the
1d8c95a3
DC
299 * tail of the given LSN to maintain insert order for push traversals. The
300 * cursor is optional, allowing repeated updates to the same LSN to avoid
e44f4112 301 * repeated traversals. This should not be called with an empty list.
cd4a3c50
DC
302 */
303static void
304xfs_ail_splice(
1d8c95a3
DC
305 struct xfs_ail *ailp,
306 struct xfs_ail_cursor *cur,
307 struct list_head *list,
308 xfs_lsn_t lsn)
cd4a3c50 309{
e44f4112
AE
310 struct xfs_log_item *lip;
311
312 ASSERT(!list_empty(list));
cd4a3c50 313
1d8c95a3 314 /*
e44f4112
AE
315 * Use the cursor to determine the insertion point if one is
316 * provided. If not, or if the one we got is not valid,
317 * find the place in the AIL where the items belong.
1d8c95a3 318 */
e44f4112
AE
319 lip = cur ? cur->item : NULL;
320 if (!lip || (__psint_t) lip & 1)
1d8c95a3
DC
321 lip = __xfs_trans_ail_cursor_last(ailp, lsn);
322
e44f4112
AE
323 /*
324 * If a cursor is provided, we know we're processing the AIL
325 * in lsn order, and future items to be spliced in will
326 * follow the last one being inserted now. Update the
327 * cursor to point to that last item, now while we have a
328 * reliable pointer to it.
329 */
330 if (cur)
331 cur->item = list_entry(list->prev, struct xfs_log_item, li_ail);
cd4a3c50 332
1d8c95a3 333 /*
e44f4112
AE
334 * Finally perform the splice. Unless the AIL was empty,
335 * lip points to the item in the AIL _after_ which the new
336 * items should go. If lip is null the AIL was empty, so
337 * the new items go at the head of the AIL.
1d8c95a3 338 */
e44f4112
AE
339 if (lip)
340 list_splice(list, &lip->li_ail);
341 else
342 list_splice(list, &ailp->xa_ail);
cd4a3c50
DC
343}
344
345/*
346 * Delete the given item from the AIL. Return a pointer to the item.
347 */
348static void
349xfs_ail_delete(
350 struct xfs_ail *ailp,
351 xfs_log_item_t *lip)
352{
353 xfs_ail_check(ailp, lip);
354 list_del(&lip->li_ail);
355 xfs_trans_ail_cursor_clear(ailp, lip);
356}
357
0030807c
CH
358static long
359xfsaild_push(
360 struct xfs_ail *ailp)
249a8c11 361{
9e7004e7 362 xfs_mount_t *mp = ailp->xa_mount;
af3e4022 363 struct xfs_ail_cursor cur;
9e7004e7
DC
364 xfs_log_item_t *lip;
365 xfs_lsn_t lsn;
fe0da767 366 xfs_lsn_t target;
9e7004e7 367 long tout = 10;
9e7004e7
DC
368 int stuck = 0;
369 int count = 0;
370 int push_xfsbufd = 0;
1da177e4 371
670ce93f
DC
372 /*
373 * If last time we ran we encountered pinned items, force the log first
374 * and wait for it before pushing again.
375 */
c7e8f268 376 spin_lock(&ailp->xa_lock);
670ce93f
DC
377 if (ailp->xa_last_pushed_lsn == 0 && ailp->xa_log_flush &&
378 !list_empty(&ailp->xa_ail)) {
379 ailp->xa_log_flush = 0;
380 spin_unlock(&ailp->xa_lock);
381 XFS_STATS_INC(xs_push_ail_flush);
382 xfs_log_force(mp, XFS_LOG_SYNC);
383 spin_lock(&ailp->xa_lock);
384 }
385
fe0da767 386 target = ailp->xa_target;
af3e4022 387 lip = xfs_trans_ail_cursor_first(ailp, &cur, ailp->xa_last_pushed_lsn);
249a8c11 388 if (!lip || XFS_FORCED_SHUTDOWN(mp)) {
1da177e4 389 /*
249a8c11 390 * AIL is empty or our push has reached the end.
1da177e4 391 */
af3e4022 392 xfs_trans_ail_cursor_done(ailp, &cur);
c7e8f268 393 spin_unlock(&ailp->xa_lock);
9e7004e7 394 goto out_done;
1da177e4
LT
395 }
396
397 XFS_STATS_INC(xs_push_ail);
398
399 /*
400 * While the item we are looking at is below the given threshold
249a8c11 401 * try to flush it out. We'd like not to stop until we've at least
1da177e4 402 * tried to push on everything in the AIL with an LSN less than
249a8c11
DC
403 * the given threshold.
404 *
405 * However, we will stop after a certain number of pushes and wait
406 * for a reduced timeout to fire before pushing further. This
407 * prevents use from spinning when we can't do anything or there is
408 * lots of contention on the AIL lists.
1da177e4 409 */
249a8c11 410 lsn = lip->li_lsn;
50e86686 411 while ((XFS_LSN_CMP(lip->li_lsn, target) <= 0)) {
249a8c11 412 int lock_result;
1da177e4 413 /*
249a8c11
DC
414 * If we can lock the item without sleeping, unlock the AIL
415 * lock and flush the item. Then re-grab the AIL lock so we
416 * can look for the next item on the AIL. List changes are
417 * handled by the AIL lookup functions internally
1da177e4 418 *
249a8c11
DC
419 * If we can't lock the item, either its holder will flush it
420 * or it is already being flushed or it is being relogged. In
421 * any of these case it is being taken care of and we can just
422 * skip to the next item in the list.
1da177e4
LT
423 */
424 lock_result = IOP_TRYLOCK(lip);
c7e8f268 425 spin_unlock(&ailp->xa_lock);
1da177e4 426 switch (lock_result) {
249a8c11 427 case XFS_ITEM_SUCCESS:
1da177e4 428 XFS_STATS_INC(xs_push_ail_success);
9e4c109a
CH
429 trace_xfs_ail_push(lip);
430
1da177e4 431 IOP_PUSH(lip);
0bf6a5bd 432 ailp->xa_last_pushed_lsn = lsn;
1da177e4
LT
433 break;
434
249a8c11 435 case XFS_ITEM_PUSHBUF:
1da177e4 436 XFS_STATS_INC(xs_push_ail_pushbuf);
9e4c109a 437 trace_xfs_ail_pushbuf(lip);
17b38471
CH
438
439 if (!IOP_PUSHBUF(lip)) {
9e4c109a 440 trace_xfs_ail_pushbuf_pinned(lip);
17b38471 441 stuck++;
2900b339 442 ailp->xa_log_flush++;
17b38471
CH
443 } else {
444 ailp->xa_last_pushed_lsn = lsn;
445 }
d808f617 446 push_xfsbufd = 1;
1da177e4
LT
447 break;
448
249a8c11 449 case XFS_ITEM_PINNED:
1da177e4 450 XFS_STATS_INC(xs_push_ail_pinned);
9e4c109a
CH
451 trace_xfs_ail_pinned(lip);
452
249a8c11 453 stuck++;
670ce93f 454 ailp->xa_log_flush++;
1da177e4
LT
455 break;
456
249a8c11 457 case XFS_ITEM_LOCKED:
1da177e4 458 XFS_STATS_INC(xs_push_ail_locked);
9e4c109a 459 trace_xfs_ail_locked(lip);
249a8c11 460 stuck++;
1da177e4
LT
461 break;
462
249a8c11 463 default:
1da177e4
LT
464 ASSERT(0);
465 break;
466 }
467
c7e8f268 468 spin_lock(&ailp->xa_lock);
249a8c11
DC
469 /* should we bother continuing? */
470 if (XFS_FORCED_SHUTDOWN(mp))
1da177e4 471 break;
249a8c11
DC
472 ASSERT(mp->m_log);
473
474 count++;
1da177e4 475
249a8c11
DC
476 /*
477 * Are there too many items we can't do anything with?
478 * If we we are skipping too many items because we can't flush
479 * them or they are already being flushed, we back off and
480 * given them time to complete whatever operation is being
481 * done. i.e. remove pressure from the AIL while we can't make
482 * progress so traversals don't slow down further inserts and
483 * removals to/from the AIL.
484 *
485 * The value of 100 is an arbitrary magic number based on
486 * observation.
487 */
488 if (stuck > 100)
489 break;
490
af3e4022 491 lip = xfs_trans_ail_cursor_next(ailp, &cur);
249a8c11
DC
492 if (lip == NULL)
493 break;
249a8c11 494 lsn = lip->li_lsn;
1da177e4 495 }
af3e4022 496 xfs_trans_ail_cursor_done(ailp, &cur);
c7e8f268 497 spin_unlock(&ailp->xa_lock);
1da177e4 498
d808f617
DC
499 if (push_xfsbufd) {
500 /* we've got delayed write buffers to flush */
501 wake_up_process(mp->m_ddev_targp->bt_task);
502 }
503
0bf6a5bd 504 /* assume we have more work to do in a short while */
9e7004e7 505out_done:
92d9cd10
DC
506 if (!count) {
507 /* We're past our target or empty, so idle */
0bf6a5bd 508 ailp->xa_last_pushed_lsn = 0;
670ce93f 509 ailp->xa_log_flush = 0;
0bf6a5bd 510
0bf6a5bd 511 tout = 50;
92d9cd10
DC
512 } else if (XFS_LSN_CMP(lsn, target) >= 0) {
513 /*
514 * We reached the target so wait a bit longer for I/O to
515 * complete and remove pushed items from the AIL before we
516 * start the next scan from the start of the AIL.
517 */
453eac8a 518 tout = 50;
0bf6a5bd 519 ailp->xa_last_pushed_lsn = 0;
27d8d5fe 520 } else if ((stuck * 100) / count > 90) {
249a8c11
DC
521 /*
522 * Either there is a lot of contention on the AIL or we
523 * are stuck due to operations in progress. "Stuck" in this
524 * case is defined as >90% of the items we tried to push
525 * were stuck.
526 *
527 * Backoff a bit more to allow some I/O to complete before
670ce93f
DC
528 * restarting from the start of the AIL. This prevents us
529 * from spinning on the same items, and if they are pinned will
530 * all the restart to issue a log force to unpin the stuck
531 * items.
249a8c11 532 */
453eac8a 533 tout = 20;
670ce93f 534 ailp->xa_last_pushed_lsn = 0;
1da177e4 535 }
0bf6a5bd 536
0030807c
CH
537 return tout;
538}
539
540static int
541xfsaild(
542 void *data)
543{
544 struct xfs_ail *ailp = data;
545 long tout = 0; /* milliseconds */
546
547 while (!kthread_should_stop()) {
548 if (tout && tout <= 20)
549 __set_current_state(TASK_KILLABLE);
550 else
551 __set_current_state(TASK_INTERRUPTIBLE);
552 schedule_timeout(tout ?
553 msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);
554
555 try_to_freeze();
556
557 tout = xfsaild_push(ailp);
558 }
559
560 return 0;
453eac8a 561}
1da177e4 562
0bf6a5bd
DC
563/*
564 * This routine is called to move the tail of the AIL forward. It does this by
565 * trying to flush items in the AIL whose lsns are below the given
566 * threshold_lsn.
567 *
568 * The push is run asynchronously in a workqueue, which means the caller needs
569 * to handle waiting on the async flush for space to become available.
570 * We don't want to interrupt any push that is in progress, hence we only queue
571 * work if we set the pushing bit approriately.
572 *
573 * We do this unlocked - we only need to know whether there is anything in the
574 * AIL at the time we are called. We don't need to access the contents of
575 * any of the objects, so the lock is not needed.
576 */
577void
fd074841 578xfs_ail_push(
0bf6a5bd
DC
579 struct xfs_ail *ailp,
580 xfs_lsn_t threshold_lsn)
581{
582 xfs_log_item_t *lip;
583
584 lip = xfs_ail_min(ailp);
585 if (!lip || XFS_FORCED_SHUTDOWN(ailp->xa_mount) ||
586 XFS_LSN_CMP(threshold_lsn, ailp->xa_target) <= 0)
587 return;
588
589 /*
590 * Ensure that the new target is noticed in push code before it clears
591 * the XFS_AIL_PUSHING_BIT.
592 */
593 smp_wmb();
fe0da767 594 xfs_trans_ail_copy_lsn(ailp, &ailp->xa_target, &threshold_lsn);
0030807c
CH
595 smp_wmb();
596
597 wake_up_process(ailp->xa_task);
0bf6a5bd 598}
1da177e4 599
fd074841
DC
600/*
601 * Push out all items in the AIL immediately
602 */
603void
604xfs_ail_push_all(
605 struct xfs_ail *ailp)
606{
607 xfs_lsn_t threshold_lsn = xfs_ail_max_lsn(ailp);
608
609 if (threshold_lsn)
610 xfs_ail_push(ailp, threshold_lsn);
611}
612
0e57f6a3
DC
613/*
614 * xfs_trans_ail_update - bulk AIL insertion operation.
615 *
616 * @xfs_trans_ail_update takes an array of log items that all need to be
617 * positioned at the same LSN in the AIL. If an item is not in the AIL, it will
618 * be added. Otherwise, it will be repositioned by removing it and re-adding
619 * it to the AIL. If we move the first item in the AIL, update the log tail to
620 * match the new minimum LSN in the AIL.
621 *
622 * This function takes the AIL lock once to execute the update operations on
623 * all the items in the array, and as such should not be called with the AIL
624 * lock held. As a result, once we have the AIL lock, we need to check each log
625 * item LSN to confirm it needs to be moved forward in the AIL.
626 *
627 * To optimise the insert operation, we delete all the items from the AIL in
628 * the first pass, moving them into a temporary list, then splice the temporary
629 * list into the correct position in the AIL. This avoids needing to do an
630 * insert operation on every item.
631 *
632 * This function must be called with the AIL lock held. The lock is dropped
633 * before returning.
634 */
635void
636xfs_trans_ail_update_bulk(
637 struct xfs_ail *ailp,
1d8c95a3 638 struct xfs_ail_cursor *cur,
0e57f6a3
DC
639 struct xfs_log_item **log_items,
640 int nr_items,
641 xfs_lsn_t lsn) __releases(ailp->xa_lock)
642{
643 xfs_log_item_t *mlip;
0e57f6a3
DC
644 int mlip_changed = 0;
645 int i;
646 LIST_HEAD(tmp);
647
e44f4112 648 ASSERT(nr_items > 0); /* Not required, but true. */
0e57f6a3
DC
649 mlip = xfs_ail_min(ailp);
650
651 for (i = 0; i < nr_items; i++) {
652 struct xfs_log_item *lip = log_items[i];
653 if (lip->li_flags & XFS_LI_IN_AIL) {
654 /* check if we really need to move the item */
655 if (XFS_LSN_CMP(lsn, lip->li_lsn) <= 0)
656 continue;
657
658 xfs_ail_delete(ailp, lip);
659 if (mlip == lip)
660 mlip_changed = 1;
661 } else {
662 lip->li_flags |= XFS_LI_IN_AIL;
663 }
664 lip->li_lsn = lsn;
665 list_add(&lip->li_ail, &tmp);
666 }
667
e44f4112
AE
668 if (!list_empty(&tmp))
669 xfs_ail_splice(ailp, cur, &tmp, lsn);
0e57f6a3 670
1c304625
CH
671 if (mlip_changed) {
672 if (!XFS_FORCED_SHUTDOWN(ailp->xa_mount))
673 xlog_assign_tail_lsn_locked(ailp->xa_mount);
674 spin_unlock(&ailp->xa_lock);
675
cfb7cdca 676 xfs_log_space_wake(ailp->xa_mount);
1c304625
CH
677 } else {
678 spin_unlock(&ailp->xa_lock);
0e57f6a3 679 }
0e57f6a3
DC
680}
681
30136832
DC
682/*
683 * xfs_trans_ail_delete_bulk - remove multiple log items from the AIL
684 *
685 * @xfs_trans_ail_delete_bulk takes an array of log items that all need to
686 * removed from the AIL. The caller is already holding the AIL lock, and done
687 * all the checks necessary to ensure the items passed in via @log_items are
688 * ready for deletion. This includes checking that the items are in the AIL.
689 *
690 * For each log item to be removed, unlink it from the AIL, clear the IN_AIL
691 * flag from the item and reset the item's lsn to 0. If we remove the first
692 * item in the AIL, update the log tail to match the new minimum LSN in the
693 * AIL.
694 *
695 * This function will not drop the AIL lock until all items are removed from
696 * the AIL to minimise the amount of lock traffic on the AIL. This does not
697 * greatly increase the AIL hold time, but does significantly reduce the amount
698 * of traffic on the lock, especially during IO completion.
699 *
700 * This function must be called with the AIL lock held. The lock is dropped
701 * before returning.
702 */
703void
704xfs_trans_ail_delete_bulk(
705 struct xfs_ail *ailp,
706 struct xfs_log_item **log_items,
707 int nr_items) __releases(ailp->xa_lock)
708{
709 xfs_log_item_t *mlip;
30136832
DC
710 int mlip_changed = 0;
711 int i;
712
713 mlip = xfs_ail_min(ailp);
714
715 for (i = 0; i < nr_items; i++) {
716 struct xfs_log_item *lip = log_items[i];
717 if (!(lip->li_flags & XFS_LI_IN_AIL)) {
718 struct xfs_mount *mp = ailp->xa_mount;
719
720 spin_unlock(&ailp->xa_lock);
721 if (!XFS_FORCED_SHUTDOWN(mp)) {
6a19d939 722 xfs_alert_tag(mp, XFS_PTAG_AILDELETE,
30136832
DC
723 "%s: attempting to delete a log item that is not in the AIL",
724 __func__);
725 xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
726 }
727 return;
728 }
729
730 xfs_ail_delete(ailp, lip);
731 lip->li_flags &= ~XFS_LI_IN_AIL;
732 lip->li_lsn = 0;
733 if (mlip == lip)
734 mlip_changed = 1;
735 }
736
1c304625
CH
737 if (mlip_changed) {
738 if (!XFS_FORCED_SHUTDOWN(ailp->xa_mount))
739 xlog_assign_tail_lsn_locked(ailp->xa_mount);
740 spin_unlock(&ailp->xa_lock);
741
cfb7cdca 742 xfs_log_space_wake(ailp->xa_mount);
1c304625
CH
743 } else {
744 spin_unlock(&ailp->xa_lock);
30136832 745 }
30136832 746}
1da177e4 747
1da177e4
LT
748/*
749 * The active item list (AIL) is a doubly linked list of log
750 * items sorted by ascending lsn. The base of the list is
751 * a forw/back pointer pair embedded in the xfs mount structure.
752 * The base is initialized with both pointers pointing to the
753 * base. This case always needs to be distinguished, because
754 * the base has no lsn to look at. We almost always insert
755 * at the end of the list, so on inserts we search from the
756 * end of the list to find where the new item belongs.
757 */
758
759/*
760 * Initialize the doubly linked list to point only to itself.
761 */
249a8c11 762int
1da177e4
LT
763xfs_trans_ail_init(
764 xfs_mount_t *mp)
765{
82fa9012
DC
766 struct xfs_ail *ailp;
767
768 ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL);
769 if (!ailp)
770 return ENOMEM;
771
772 ailp->xa_mount = mp;
773 INIT_LIST_HEAD(&ailp->xa_ail);
af3e4022 774 INIT_LIST_HEAD(&ailp->xa_cursors);
c7e8f268 775 spin_lock_init(&ailp->xa_lock);
0030807c
CH
776
777 ailp->xa_task = kthread_run(xfsaild, ailp, "xfsaild/%s",
778 ailp->xa_mount->m_fsname);
779 if (IS_ERR(ailp->xa_task))
780 goto out_free_ailp;
781
27d8d5fe
DC
782 mp->m_ail = ailp;
783 return 0;
0030807c
CH
784
785out_free_ailp:
786 kmem_free(ailp);
787 return ENOMEM;
249a8c11
DC
788}
789
790void
791xfs_trans_ail_destroy(
792 xfs_mount_t *mp)
793{
82fa9012
DC
794 struct xfs_ail *ailp = mp->m_ail;
795
0030807c 796 kthread_stop(ailp->xa_task);
82fa9012 797 kmem_free(ailp);
1da177e4 798}