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drm/tests: Add test for drm_atomic_helper_check_modeset()
[drm/drm-misc.git] / fs / xfs / xfs_extent_busy.c
blobea43c9a6e54c12bdb36a3614d8f2054aeceb7151
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
4 * Copyright (c) 2010 David Chinner.
5 * Copyright (c) 2011 Christoph Hellwig.
6 * All Rights Reserved.
7 */
8 #include "xfs.h"
9 #include "xfs_fs.h"
10 #include "xfs_format.h"
11 #include "xfs_log_format.h"
12 #include "xfs_shared.h"
13 #include "xfs_trans_resv.h"
14 #include "xfs_mount.h"
15 #include "xfs_alloc.h"
16 #include "xfs_extent_busy.h"
17 #include "xfs_trace.h"
18 #include "xfs_trans.h"
19 #include "xfs_log.h"
20 #include "xfs_ag.h"
21 #include "xfs_rtgroup.h"
22
23 struct xfs_extent_busy_tree {
24 spinlock_t eb_lock;
25 struct rb_root eb_tree;
26 unsigned int eb_gen;
27 wait_queue_head_t eb_wait;
28 };
29
30 static void
31 xfs_extent_busy_insert_list(
32 struct xfs_group *xg,
33 xfs_agblock_t bno,
34 xfs_extlen_t len,
35 unsigned int flags,
36 struct list_head *busy_list)
37 {
38 struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
39 struct xfs_extent_busy *new;
40 struct xfs_extent_busy *busyp;
41 struct rb_node **rbp;
42 struct rb_node *parent = NULL;
43
44 new = kzalloc(sizeof(struct xfs_extent_busy),
45 GFP_KERNEL | __GFP_NOFAIL);
46 new->group = xfs_group_hold(xg);
47 new->bno = bno;
48 new->length = len;
49 INIT_LIST_HEAD(&new->list);
50 new->flags = flags;
51
52 /* trace before insert to be able to see failed inserts */
53 trace_xfs_extent_busy(xg, bno, len);
54
55 spin_lock(&eb->eb_lock);
56 rbp = &eb->eb_tree.rb_node;
57 while (*rbp) {
58 parent = *rbp;
59 busyp = rb_entry(parent, struct xfs_extent_busy, rb_node);
60
61 if (new->bno < busyp->bno) {
62 rbp = &(*rbp)->rb_left;
63 ASSERT(new->bno + new->length <= busyp->bno);
64 } else if (new->bno > busyp->bno) {
65 rbp = &(*rbp)->rb_right;
66 ASSERT(bno >= busyp->bno + busyp->length);
67 } else {
68 ASSERT(0);
69 }
70 }
71
72 rb_link_node(&new->rb_node, parent, rbp);
73 rb_insert_color(&new->rb_node, &eb->eb_tree);
74
75 /* always process discard lists in fifo order */
76 list_add_tail(&new->list, busy_list);
77 spin_unlock(&eb->eb_lock);
78 }
79
80 void
81 xfs_extent_busy_insert(
82 struct xfs_trans *tp,
83 struct xfs_group *xg,
84 xfs_agblock_t bno,
85 xfs_extlen_t len,
86 unsigned int flags)
87 {
88 xfs_extent_busy_insert_list(xg, bno, len, flags, &tp->t_busy);
89 }
90
91 void
92 xfs_extent_busy_insert_discard(
93 struct xfs_group *xg,
94 xfs_agblock_t bno,
95 xfs_extlen_t len,
96 struct list_head *busy_list)
97 {
98 xfs_extent_busy_insert_list(xg, bno, len, XFS_EXTENT_BUSY_DISCARDED,
99 busy_list);
100 }
101
102 /*
103 * Search for a busy extent within the range of the extent we are about to
104 * allocate. You need to be holding the busy extent tree lock when calling
105 * xfs_extent_busy_search(). This function returns 0 for no overlapping busy
106 * extent, -1 for an overlapping but not exact busy extent, and 1 for an exact
107 * match. This is done so that a non-zero return indicates an overlap that
108 * will require a synchronous transaction, but it can still be
109 * used to distinguish between a partial or exact match.
110 */
111 int
112 xfs_extent_busy_search(
113 struct xfs_group *xg,
114 xfs_agblock_t bno,
115 xfs_extlen_t len)
116 {
117 struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
118 struct rb_node *rbp;
119 struct xfs_extent_busy *busyp;
120 int match = 0;
121
122 /* find closest start bno overlap */
123 spin_lock(&eb->eb_lock);
124 rbp = eb->eb_tree.rb_node;
125 while (rbp) {
126 busyp = rb_entry(rbp, struct xfs_extent_busy, rb_node);
127 if (bno < busyp->bno) {
128 /* may overlap, but exact start block is lower */
129 if (bno + len > busyp->bno)
130 match = -1;
131 rbp = rbp->rb_left;
132 } else if (bno > busyp->bno) {
133 /* may overlap, but exact start block is higher */
134 if (bno < busyp->bno + busyp->length)
135 match = -1;
136 rbp = rbp->rb_right;
137 } else {
138 /* bno matches busyp, length determines exact match */
139 match = (busyp->length == len) ? 1 : -1;
140 break;
141 }
142 }
143 spin_unlock(&eb->eb_lock);
144 return match;
145 }
146
147 /*
148 * The found free extent [fbno, fend] overlaps part or all of the given busy
149 * extent. If the overlap covers the beginning, the end, or all of the busy
150 * extent, the overlapping portion can be made unbusy and used for the
151 * allocation. We can't split a busy extent because we can't modify a
152 * transaction/CIL context busy list, but we can update an entry's block
153 * number or length.
154 *
155 * Returns true if the extent can safely be reused, or false if the search
156 * needs to be restarted.
157 */
158 STATIC bool
159 xfs_extent_busy_update_extent(
160 struct xfs_group *xg,
161 struct xfs_extent_busy *busyp,
162 xfs_agblock_t fbno,
163 xfs_extlen_t flen,
164 bool userdata)
165 __releases(&eb->eb_lock)
166 __acquires(&eb->eb_lock)
167 {
168 struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
169 xfs_agblock_t fend = fbno + flen;
170 xfs_agblock_t bbno = busyp->bno;
171 xfs_agblock_t bend = bbno + busyp->length;
172
173 /*
174 * This extent is currently being discarded. Give the thread
175 * performing the discard a chance to mark the extent unbusy
176 * and retry.
177 */
178 if (busyp->flags & XFS_EXTENT_BUSY_DISCARDED) {
179 spin_unlock(&eb->eb_lock);
180 delay(1);
181 spin_lock(&eb->eb_lock);
182 return false;
183 }
184
185 /*
186 * If there is a busy extent overlapping a user allocation, we have
187 * no choice but to force the log and retry the search.
188 *
189 * Fortunately this does not happen during normal operation, but
190 * only if the filesystem is very low on space and has to dip into
191 * the AGFL for normal allocations.
192 */
193 if (userdata)
194 goto out_force_log;
195
196 if (bbno < fbno && bend > fend) {
197 /*
198 * Case 1:
199 * bbno bend
200 * +BBBBBBBBBBBBBBBBB+
201 * +---------+
202 * fbno fend
203 */
204
205 /*
206 * We would have to split the busy extent to be able to track
207 * it correct, which we cannot do because we would have to
208 * modify the list of busy extents attached to the transaction
209 * or CIL context, which is immutable.
210 *
211 * Force out the log to clear the busy extent and retry the
212 * search.
213 */
214 goto out_force_log;
215 } else if (bbno >= fbno && bend <= fend) {
216 /*
217 * Case 2:
218 * bbno bend
219 * +BBBBBBBBBBBBBBBBB+
220 * +-----------------+
221 * fbno fend
222 *
223 * Case 3:
224 * bbno bend
225 * +BBBBBBBBBBBBBBBBB+
226 * +--------------------------+
227 * fbno fend
228 *
229 * Case 4:
230 * bbno bend
231 * +BBBBBBBBBBBBBBBBB+
232 * +--------------------------+
233 * fbno fend
234 *
235 * Case 5:
236 * bbno bend
237 * +BBBBBBBBBBBBBBBBB+
238 * +-----------------------------------+
239 * fbno fend
240 *
241 */
242
243 /*
244 * The busy extent is fully covered by the extent we are
245 * allocating, and can simply be removed from the rbtree.
246 * However we cannot remove it from the immutable list
247 * tracking busy extents in the transaction or CIL context,
248 * so set the length to zero to mark it invalid.
249 *
250 * We also need to restart the busy extent search from the
251 * tree root, because erasing the node can rearrange the
252 * tree topology.
253 */
254 rb_erase(&busyp->rb_node, &eb->eb_tree);
255 busyp->length = 0;
256 return false;
257 } else if (fend < bend) {
258 /*
259 * Case 6:
260 * bbno bend
261 * +BBBBBBBBBBBBBBBBB+
262 * +---------+
263 * fbno fend
264 *
265 * Case 7:
266 * bbno bend
267 * +BBBBBBBBBBBBBBBBB+
268 * +------------------+
269 * fbno fend
270 *
271 */
272 busyp->bno = fend;
273 busyp->length = bend - fend;
274 } else if (bbno < fbno) {
275 /*
276 * Case 8:
277 * bbno bend
278 * +BBBBBBBBBBBBBBBBB+
279 * +-------------+
280 * fbno fend
281 *
282 * Case 9:
283 * bbno bend
284 * +BBBBBBBBBBBBBBBBB+
285 * +----------------------+
286 * fbno fend
287 */
288 busyp->length = fbno - busyp->bno;
289 } else {
290 ASSERT(0);
291 }
292
293 trace_xfs_extent_busy_reuse(xg, fbno, flen);
294 return true;
295
296 out_force_log:
297 spin_unlock(&eb->eb_lock);
298 xfs_log_force(xg->xg_mount, XFS_LOG_SYNC);
299 trace_xfs_extent_busy_force(xg, fbno, flen);
300 spin_lock(&eb->eb_lock);
301 return false;
302 }
303
304 /*
305 * For a given extent [fbno, flen], make sure we can reuse it safely.
306 */
307 void
308 xfs_extent_busy_reuse(
309 struct xfs_group *xg,
310 xfs_agblock_t fbno,
311 xfs_extlen_t flen,
312 bool userdata)
313 {
314 struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
315 struct rb_node *rbp;
316
317 ASSERT(flen > 0);
318 spin_lock(&eb->eb_lock);
319 restart:
320 rbp = eb->eb_tree.rb_node;
321 while (rbp) {
322 struct xfs_extent_busy *busyp =
323 rb_entry(rbp, struct xfs_extent_busy, rb_node);
324 xfs_agblock_t bbno = busyp->bno;
325 xfs_agblock_t bend = bbno + busyp->length;
326
327 if (fbno + flen <= bbno) {
328 rbp = rbp->rb_left;
329 continue;
330 } else if (fbno >= bend) {
331 rbp = rbp->rb_right;
332 continue;
333 }
334
335 if (!xfs_extent_busy_update_extent(xg, busyp, fbno, flen,
336 userdata))
337 goto restart;
338 }
339 spin_unlock(&eb->eb_lock);
340 }
341
342 /*
343 * For a given extent [fbno, flen], search the busy extent list to find a
344 * subset of the extent that is not busy. If *rlen is smaller than
345 * args->minlen no suitable extent could be found, and the higher level
346 * code needs to force out the log and retry the allocation.
347 *
348 * Return the current busy generation for the group if the extent is busy. This
349 * value can be used to wait for at least one of the currently busy extents
350 * to be cleared. Note that the busy list is not guaranteed to be empty after
351 * the gen is woken. The state of a specific extent must always be confirmed
352 * with another call to xfs_extent_busy_trim() before it can be used.
353 */
354 bool
355 xfs_extent_busy_trim(
356 struct xfs_group *xg,
357 xfs_extlen_t minlen,
358 xfs_extlen_t maxlen,
359 xfs_agblock_t *bno,
360 xfs_extlen_t *len,
361 unsigned *busy_gen)
362 {
363 struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
364 xfs_agblock_t fbno;
365 xfs_extlen_t flen;
366 struct rb_node *rbp;
367 bool ret = false;
368
369 ASSERT(*len > 0);
370
371 spin_lock(&eb->eb_lock);
372 fbno = *bno;
373 flen = *len;
374 rbp = eb->eb_tree.rb_node;
375 while (rbp && flen >= minlen) {
376 struct xfs_extent_busy *busyp =
377 rb_entry(rbp, struct xfs_extent_busy, rb_node);
378 xfs_agblock_t fend = fbno + flen;
379 xfs_agblock_t bbno = busyp->bno;
380 xfs_agblock_t bend = bbno + busyp->length;
381
382 if (fend <= bbno) {
383 rbp = rbp->rb_left;
384 continue;
385 } else if (fbno >= bend) {
386 rbp = rbp->rb_right;
387 continue;
388 }
389
390 if (bbno <= fbno) {
391 /* start overlap */
392
393 /*
394 * Case 1:
395 * bbno bend
396 * +BBBBBBBBBBBBBBBBB+
397 * +---------+
398 * fbno fend
399 *
400 * Case 2:
401 * bbno bend
402 * +BBBBBBBBBBBBBBBBB+
403 * +-------------+
404 * fbno fend
405 *
406 * Case 3:
407 * bbno bend
408 * +BBBBBBBBBBBBBBBBB+
409 * +-------------+
410 * fbno fend
411 *
412 * Case 4:
413 * bbno bend
414 * +BBBBBBBBBBBBBBBBB+
415 * +-----------------+
416 * fbno fend
417 *
418 * No unbusy region in extent, return failure.
419 */
420 if (fend <= bend)
421 goto fail;
422
423 /*
424 * Case 5:
425 * bbno bend
426 * +BBBBBBBBBBBBBBBBB+
427 * +----------------------+
428 * fbno fend
429 *
430 * Case 6:
431 * bbno bend
432 * +BBBBBBBBBBBBBBBBB+
433 * +--------------------------+
434 * fbno fend
435 *
436 * Needs to be trimmed to:
437 * +-------+
438 * fbno fend
439 */
440 fbno = bend;
441 } else if (bend >= fend) {
442 /* end overlap */
443
444 /*
445 * Case 7:
446 * bbno bend
447 * +BBBBBBBBBBBBBBBBB+
448 * +------------------+
449 * fbno fend
450 *
451 * Case 8:
452 * bbno bend
453 * +BBBBBBBBBBBBBBBBB+
454 * +--------------------------+
455 * fbno fend
456 *
457 * Needs to be trimmed to:
458 * +-------+
459 * fbno fend
460 */
461 fend = bbno;
462 } else {
463 /* middle overlap */
464
465 /*
466 * Case 9:
467 * bbno bend
468 * +BBBBBBBBBBBBBBBBB+
469 * +-----------------------------------+
470 * fbno fend
471 *
472 * Can be trimmed to:
473 * +-------+ OR +-------+
474 * fbno fend fbno fend
475 *
476 * Backward allocation leads to significant
477 * fragmentation of directories, which degrades
478 * directory performance, therefore we always want to
479 * choose the option that produces forward allocation
480 * patterns.
481 * Preferring the lower bno extent will make the next
482 * request use "fend" as the start of the next
483 * allocation; if the segment is no longer busy at
484 * that point, we'll get a contiguous allocation, but
485 * even if it is still busy, we will get a forward
486 * allocation.
487 * We try to avoid choosing the segment at "bend",
488 * because that can lead to the next allocation
489 * taking the segment at "fbno", which would be a
490 * backward allocation. We only use the segment at
491 * "fbno" if it is much larger than the current
492 * requested size, because in that case there's a
493 * good chance subsequent allocations will be
494 * contiguous.
495 */
496 if (bbno - fbno >= maxlen) {
497 /* left candidate fits perfect */
498 fend = bbno;
499 } else if (fend - bend >= maxlen * 4) {
500 /* right candidate has enough free space */
501 fbno = bend;
502 } else if (bbno - fbno >= minlen) {
503 /* left candidate fits minimum requirement */
504 fend = bbno;
505 } else {
506 goto fail;
507 }
508 }
509
510 flen = fend - fbno;
511 }
512 out:
513
514 if (fbno != *bno || flen != *len) {
515 trace_xfs_extent_busy_trim(xg, *bno, *len, fbno, flen);
516 *bno = fbno;
517 *len = flen;
518 *busy_gen = eb->eb_gen;
519 ret = true;
520 }
521 spin_unlock(&eb->eb_lock);
522 return ret;
523 fail:
524 /*
525 * Return a zero extent length as failure indications. All callers
526 * re-check if the trimmed extent satisfies the minlen requirement.
527 */
528 flen = 0;
529 goto out;
530 }
531
532 static bool
533 xfs_extent_busy_clear_one(
534 struct xfs_extent_busy *busyp,
535 bool do_discard)
536 {
537 struct xfs_extent_busy_tree *eb = busyp->group->xg_busy_extents;
538
539 if (busyp->length) {
540 if (do_discard &&
541 !(busyp->flags & XFS_EXTENT_BUSY_SKIP_DISCARD)) {
542 busyp->flags = XFS_EXTENT_BUSY_DISCARDED;
543 return false;
544 }
545 trace_xfs_extent_busy_clear(busyp->group, busyp->bno,
546 busyp->length);
547 rb_erase(&busyp->rb_node, &eb->eb_tree);
548 }
549
550 list_del_init(&busyp->list);
551 xfs_group_put(busyp->group);
552 kfree(busyp);
553 return true;
554 }
555
556 /*
557 * Remove all extents on the passed in list from the busy extents tree.
558 * If do_discard is set skip extents that need to be discarded, and mark
559 * these as undergoing a discard operation instead.
560 */
561 void
562 xfs_extent_busy_clear(
563 struct list_head *list,
564 bool do_discard)
565 {
566 struct xfs_extent_busy *busyp, *next;
567
568 busyp = list_first_entry_or_null(list, typeof(*busyp), list);
569 if (!busyp)
570 return;
571
572 do {
573 struct xfs_group *xg = xfs_group_hold(busyp->group);
574 struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
575 bool wakeup = false;
576
577 spin_lock(&eb->eb_lock);
578 do {
579 next = list_next_entry(busyp, list);
580 if (xfs_extent_busy_clear_one(busyp, do_discard))
581 wakeup = true;
582 busyp = next;
583 } while (!list_entry_is_head(busyp, list, list) &&
584 busyp->group == xg);
585
586 if (wakeup) {
587 eb->eb_gen++;
588 wake_up_all(&eb->eb_wait);
589 }
590 spin_unlock(&eb->eb_lock);
591 xfs_group_put(xg);
592 } while (!list_entry_is_head(busyp, list, list));
593 }
594
595 /*
596 * Flush out all busy extents for this group.
597 *
598 * If the current transaction is holding busy extents, the caller may not want
599 * to wait for committed busy extents to resolve. If we are being told just to
600 * try a flush or progress has been made since we last skipped a busy extent,
601 * return immediately to allow the caller to try again.
602 *
603 * If we are freeing extents, we might actually be holding the only free extents
604 * in the transaction busy list and the log force won't resolve that situation.
605 * In this case, we must return -EAGAIN to avoid a deadlock by informing the
606 * caller it needs to commit the busy extents it holds before retrying the
607 * extent free operation.
608 */
609 int
610 xfs_extent_busy_flush(
611 struct xfs_trans *tp,
612 struct xfs_group *xg,
613 unsigned busy_gen,
614 uint32_t alloc_flags)
615 {
616 struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
617 DEFINE_WAIT (wait);
618 int error;
619
620 error = xfs_log_force(tp->t_mountp, XFS_LOG_SYNC);
621 if (error)
622 return error;
623
624 /* Avoid deadlocks on uncommitted busy extents. */
625 if (!list_empty(&tp->t_busy)) {
626 if (alloc_flags & XFS_ALLOC_FLAG_TRYFLUSH)
627 return 0;
628
629 if (busy_gen != READ_ONCE(eb->eb_gen))
630 return 0;
631
632 if (alloc_flags & XFS_ALLOC_FLAG_FREEING)
633 return -EAGAIN;
634 }
635
636 /* Wait for committed busy extents to resolve. */
637 do {
638 prepare_to_wait(&eb->eb_wait, &wait, TASK_KILLABLE);
639 if (busy_gen != READ_ONCE(eb->eb_gen))
640 break;
641 schedule();
642 } while (1);
643
644 finish_wait(&eb->eb_wait, &wait);
645 return 0;
646 }
647
648 static void
649 xfs_extent_busy_wait_group(
650 struct xfs_group *xg)
651 {
652 DEFINE_WAIT (wait);
653 struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
654
655 do {
656 prepare_to_wait(&eb->eb_wait, &wait, TASK_KILLABLE);
657 if (RB_EMPTY_ROOT(&eb->eb_tree))
658 break;
659 schedule();
660 } while (1);
661 finish_wait(&eb->eb_wait, &wait);
662 }
663
664 void
665 xfs_extent_busy_wait_all(
666 struct xfs_mount *mp)
667 {
668 struct xfs_perag *pag = NULL;
669 struct xfs_rtgroup *rtg = NULL;
670
671 while ((pag = xfs_perag_next(mp, pag)))
672 xfs_extent_busy_wait_group(pag_group(pag));
673
674 if (xfs_has_rtgroups(mp))
675 while ((rtg = xfs_rtgroup_next(mp, rtg)))
676 xfs_extent_busy_wait_group(rtg_group(rtg));
677 }
678
679 /*
680 * Callback for list_sort to sort busy extents by the group they reside in.
681 */
682 int
683 xfs_extent_busy_ag_cmp(
684 void *priv,
685 const struct list_head *l1,
686 const struct list_head *l2)
687 {
688 struct xfs_extent_busy *b1 =
689 container_of(l1, struct xfs_extent_busy, list);
690 struct xfs_extent_busy *b2 =
691 container_of(l2, struct xfs_extent_busy, list);
692 s32 diff;
693
694 diff = b1->group->xg_gno - b2->group->xg_gno;
695 if (!diff)
696 diff = b1->bno - b2->bno;
697 return diff;
698 }
699
700 /* Are there any busy extents in this group? */
701 bool
702 xfs_extent_busy_list_empty(
703 struct xfs_group *xg,
704 unsigned *busy_gen)
705 {
706 struct xfs_extent_busy_tree *eb = xg->xg_busy_extents;
707 bool res;
708
709 spin_lock(&eb->eb_lock);
710 res = RB_EMPTY_ROOT(&eb->eb_tree);
711 *busy_gen = READ_ONCE(eb->eb_gen);
712 spin_unlock(&eb->eb_lock);
713 return res;
714 }
715
716 struct xfs_extent_busy_tree *
717 xfs_extent_busy_alloc(void)
718 {
719 struct xfs_extent_busy_tree *eb;
720
721 eb = kzalloc(sizeof(*eb), GFP_KERNEL);
722 if (!eb)
723 return NULL;
724 spin_lock_init(&eb->eb_lock);
725 init_waitqueue_head(&eb->eb_wait);
726 eb->eb_tree = RB_ROOT;
727 return eb;
728 }
Kernel DRM miscellaneous fixes and cross-tree changes