Loading...
1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * reservations.c
5 *
6 * Allocation reservations implementation
7 *
8 * Some code borrowed from fs/ext3/balloc.c and is:
9 *
10 * Copyright (C) 1992, 1993, 1994, 1995
11 * Remy Card (card@masi.ibp.fr)
12 * Laboratoire MASI - Institut Blaise Pascal
13 * Universite Pierre et Marie Curie (Paris VI)
14 *
15 * The rest is copyright (C) 2010 Novell. All rights reserved.
16 *
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public
19 * License version 2 as published by the Free Software Foundation.
20 *
21 * This program is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 * General Public License for more details.
25 */
26
27#include <linux/fs.h>
28#include <linux/types.h>
29#include <linux/highmem.h>
30#include <linux/bitops.h>
31#include <linux/list.h>
32
33#include <cluster/masklog.h>
34
35#include "ocfs2.h"
36#include "ocfs2_trace.h"
37
38#ifdef CONFIG_OCFS2_DEBUG_FS
39#define OCFS2_CHECK_RESERVATIONS
40#endif
41
42static DEFINE_SPINLOCK(resv_lock);
43
44#define OCFS2_MIN_RESV_WINDOW_BITS 8
45#define OCFS2_MAX_RESV_WINDOW_BITS 1024
46
47int ocfs2_dir_resv_allowed(struct ocfs2_super *osb)
48{
49 return (osb->osb_resv_level && osb->osb_dir_resv_level);
50}
51
52static unsigned int ocfs2_resv_window_bits(struct ocfs2_reservation_map *resmap,
53 struct ocfs2_alloc_reservation *resv)
54{
55 struct ocfs2_super *osb = resmap->m_osb;
56 unsigned int bits;
57
58 if (!(resv->r_flags & OCFS2_RESV_FLAG_DIR)) {
59 /* 8, 16, 32, 64, 128, 256, 512, 1024 */
60 bits = 4 << osb->osb_resv_level;
61 } else {
62 bits = 4 << osb->osb_dir_resv_level;
63 }
64 return bits;
65}
66
67static inline unsigned int ocfs2_resv_end(struct ocfs2_alloc_reservation *resv)
68{
69 if (resv->r_len)
70 return resv->r_start + resv->r_len - 1;
71 return resv->r_start;
72}
73
74static inline int ocfs2_resv_empty(struct ocfs2_alloc_reservation *resv)
75{
76 return !!(resv->r_len == 0);
77}
78
79static inline int ocfs2_resmap_disabled(struct ocfs2_reservation_map *resmap)
80{
81 if (resmap->m_osb->osb_resv_level == 0)
82 return 1;
83 return 0;
84}
85
86static void ocfs2_dump_resv(struct ocfs2_reservation_map *resmap)
87{
88 struct ocfs2_super *osb = resmap->m_osb;
89 struct rb_node *node;
90 struct ocfs2_alloc_reservation *resv;
91 int i = 0;
92
93 mlog(ML_NOTICE, "Dumping resmap for device %s. Bitmap length: %u\n",
94 osb->dev_str, resmap->m_bitmap_len);
95
96 node = rb_first(&resmap->m_reservations);
97 while (node) {
98 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
99
100 mlog(ML_NOTICE, "start: %u\tend: %u\tlen: %u\tlast_start: %u"
101 "\tlast_len: %u\n", resv->r_start,
102 ocfs2_resv_end(resv), resv->r_len, resv->r_last_start,
103 resv->r_last_len);
104
105 node = rb_next(node);
106 i++;
107 }
108
109 mlog(ML_NOTICE, "%d reservations found. LRU follows\n", i);
110
111 i = 0;
112 list_for_each_entry(resv, &resmap->m_lru, r_lru) {
113 mlog(ML_NOTICE, "LRU(%d) start: %u\tend: %u\tlen: %u\t"
114 "last_start: %u\tlast_len: %u\n", i, resv->r_start,
115 ocfs2_resv_end(resv), resv->r_len, resv->r_last_start,
116 resv->r_last_len);
117
118 i++;
119 }
120}
121
122#ifdef OCFS2_CHECK_RESERVATIONS
123static int ocfs2_validate_resmap_bits(struct ocfs2_reservation_map *resmap,
124 int i,
125 struct ocfs2_alloc_reservation *resv)
126{
127 char *disk_bitmap = resmap->m_disk_bitmap;
128 unsigned int start = resv->r_start;
129 unsigned int end = ocfs2_resv_end(resv);
130
131 while (start <= end) {
132 if (ocfs2_test_bit(start, disk_bitmap)) {
133 mlog(ML_ERROR,
134 "reservation %d covers an allocated area "
135 "starting at bit %u!\n", i, start);
136 return 1;
137 }
138
139 start++;
140 }
141 return 0;
142}
143
144static void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap)
145{
146 unsigned int off = 0;
147 int i = 0;
148 struct rb_node *node;
149 struct ocfs2_alloc_reservation *resv;
150
151 node = rb_first(&resmap->m_reservations);
152 while (node) {
153 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
154
155 if (i > 0 && resv->r_start <= off) {
156 mlog(ML_ERROR, "reservation %d has bad start off!\n",
157 i);
158 goto bad;
159 }
160
161 if (resv->r_len == 0) {
162 mlog(ML_ERROR, "reservation %d has no length!\n",
163 i);
164 goto bad;
165 }
166
167 if (resv->r_start > ocfs2_resv_end(resv)) {
168 mlog(ML_ERROR, "reservation %d has invalid range!\n",
169 i);
170 goto bad;
171 }
172
173 if (ocfs2_resv_end(resv) >= resmap->m_bitmap_len) {
174 mlog(ML_ERROR, "reservation %d extends past bitmap!\n",
175 i);
176 goto bad;
177 }
178
179 if (ocfs2_validate_resmap_bits(resmap, i, resv))
180 goto bad;
181
182 off = ocfs2_resv_end(resv);
183 node = rb_next(node);
184
185 i++;
186 }
187 return;
188
189bad:
190 ocfs2_dump_resv(resmap);
191 BUG();
192}
193#else
194static inline void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap)
195{
196
197}
198#endif
199
200void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv)
201{
202 memset(resv, 0, sizeof(*resv));
203 INIT_LIST_HEAD(&resv->r_lru);
204}
205
206void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv,
207 unsigned int flags)
208{
209 BUG_ON(flags & ~OCFS2_RESV_TYPES);
210
211 resv->r_flags |= flags;
212}
213
214int ocfs2_resmap_init(struct ocfs2_super *osb,
215 struct ocfs2_reservation_map *resmap)
216{
217 memset(resmap, 0, sizeof(*resmap));
218
219 resmap->m_osb = osb;
220 resmap->m_reservations = RB_ROOT;
221 /* m_bitmap_len is initialized to zero by the above memset. */
222 INIT_LIST_HEAD(&resmap->m_lru);
223
224 return 0;
225}
226
227static void ocfs2_resv_mark_lru(struct ocfs2_reservation_map *resmap,
228 struct ocfs2_alloc_reservation *resv)
229{
230 assert_spin_locked(&resv_lock);
231
232 if (!list_empty(&resv->r_lru))
233 list_del_init(&resv->r_lru);
234
235 list_add_tail(&resv->r_lru, &resmap->m_lru);
236}
237
238static void __ocfs2_resv_trunc(struct ocfs2_alloc_reservation *resv)
239{
240 resv->r_len = 0;
241 resv->r_start = 0;
242}
243
244static void ocfs2_resv_remove(struct ocfs2_reservation_map *resmap,
245 struct ocfs2_alloc_reservation *resv)
246{
247 if (resv->r_flags & OCFS2_RESV_FLAG_INUSE) {
248 list_del_init(&resv->r_lru);
249 rb_erase(&resv->r_node, &resmap->m_reservations);
250 resv->r_flags &= ~OCFS2_RESV_FLAG_INUSE;
251 }
252}
253
254static void __ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
255 struct ocfs2_alloc_reservation *resv)
256{
257 assert_spin_locked(&resv_lock);
258
259 __ocfs2_resv_trunc(resv);
260 /*
261 * last_len and last_start no longer make sense if
262 * we're changing the range of our allocations.
263 */
264 resv->r_last_len = resv->r_last_start = 0;
265
266 ocfs2_resv_remove(resmap, resv);
267}
268
269/* does nothing if 'resv' is null */
270void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
271 struct ocfs2_alloc_reservation *resv)
272{
273 if (resv) {
274 spin_lock(&resv_lock);
275 __ocfs2_resv_discard(resmap, resv);
276 spin_unlock(&resv_lock);
277 }
278}
279
280static void ocfs2_resmap_clear_all_resv(struct ocfs2_reservation_map *resmap)
281{
282 struct rb_node *node;
283 struct ocfs2_alloc_reservation *resv;
284
285 assert_spin_locked(&resv_lock);
286
287 while ((node = rb_last(&resmap->m_reservations)) != NULL) {
288 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
289
290 __ocfs2_resv_discard(resmap, resv);
291 }
292}
293
294void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
295 unsigned int clen, char *disk_bitmap)
296{
297 if (ocfs2_resmap_disabled(resmap))
298 return;
299
300 spin_lock(&resv_lock);
301
302 ocfs2_resmap_clear_all_resv(resmap);
303 resmap->m_bitmap_len = clen;
304 resmap->m_disk_bitmap = disk_bitmap;
305
306 spin_unlock(&resv_lock);
307}
308
309void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap)
310{
311 /* Does nothing for now. Keep this around for API symmetry */
312}
313
314static void ocfs2_resv_insert(struct ocfs2_reservation_map *resmap,
315 struct ocfs2_alloc_reservation *new)
316{
317 struct rb_root *root = &resmap->m_reservations;
318 struct rb_node *parent = NULL;
319 struct rb_node **p = &root->rb_node;
320 struct ocfs2_alloc_reservation *tmp;
321
322 assert_spin_locked(&resv_lock);
323
324 trace_ocfs2_resv_insert(new->r_start, new->r_len);
325
326 while (*p) {
327 parent = *p;
328
329 tmp = rb_entry(parent, struct ocfs2_alloc_reservation, r_node);
330
331 if (new->r_start < tmp->r_start) {
332 p = &(*p)->rb_left;
333
334 /*
335 * This is a good place to check for
336 * overlapping reservations.
337 */
338 BUG_ON(ocfs2_resv_end(new) >= tmp->r_start);
339 } else if (new->r_start > ocfs2_resv_end(tmp)) {
340 p = &(*p)->rb_right;
341 } else {
342 /* This should never happen! */
343 mlog(ML_ERROR, "Duplicate reservation window!\n");
344 BUG();
345 }
346 }
347
348 rb_link_node(&new->r_node, parent, p);
349 rb_insert_color(&new->r_node, root);
350 new->r_flags |= OCFS2_RESV_FLAG_INUSE;
351
352 ocfs2_resv_mark_lru(resmap, new);
353
354 ocfs2_check_resmap(resmap);
355}
356
357/**
358 * ocfs2_find_resv_lhs() - find the window which contains goal
359 * @resmap: reservation map to search
360 * @goal: which bit to search for
361 *
362 * If a window containing that goal is not found, we return the window
363 * which comes before goal. Returns NULL on empty rbtree or no window
364 * before goal.
365 */
366static struct ocfs2_alloc_reservation *
367ocfs2_find_resv_lhs(struct ocfs2_reservation_map *resmap, unsigned int goal)
368{
369 struct ocfs2_alloc_reservation *resv = NULL;
370 struct ocfs2_alloc_reservation *prev_resv = NULL;
371 struct rb_node *node = resmap->m_reservations.rb_node;
372
373 assert_spin_locked(&resv_lock);
374
375 if (!node)
376 return NULL;
377
378 node = rb_first(&resmap->m_reservations);
379 while (node) {
380 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
381
382 if (resv->r_start <= goal && ocfs2_resv_end(resv) >= goal)
383 break;
384
385 /* Check if we overshot the reservation just before goal? */
386 if (resv->r_start > goal) {
387 resv = prev_resv;
388 break;
389 }
390
391 prev_resv = resv;
392 node = rb_next(node);
393 }
394
395 return resv;
396}
397
398/*
399 * We are given a range within the bitmap, which corresponds to a gap
400 * inside the reservations tree (search_start, search_len). The range
401 * can be anything from the whole bitmap, to a gap between
402 * reservations.
403 *
404 * The start value of *rstart is insignificant.
405 *
406 * This function searches the bitmap range starting at search_start
407 * with length search_len for a set of contiguous free bits. We try
408 * to find up to 'wanted' bits, but can sometimes return less.
409 *
410 * Returns the length of allocation, 0 if no free bits are found.
411 *
412 * *cstart and *clen will also be populated with the result.
413 */
414static int ocfs2_resmap_find_free_bits(struct ocfs2_reservation_map *resmap,
415 unsigned int wanted,
416 unsigned int search_start,
417 unsigned int search_len,
418 unsigned int *rstart,
419 unsigned int *rlen)
420{
421 void *bitmap = resmap->m_disk_bitmap;
422 unsigned int best_start, best_len = 0;
423 int offset, start, found;
424
425 trace_ocfs2_resmap_find_free_bits_begin(search_start, search_len,
426 wanted, resmap->m_bitmap_len);
427
428 found = best_start = best_len = 0;
429
430 start = search_start;
431 while ((offset = ocfs2_find_next_zero_bit(bitmap, resmap->m_bitmap_len,
432 start)) != -1) {
433 /* Search reached end of the region */
434 if (offset >= (search_start + search_len))
435 break;
436
437 if (offset == start) {
438 /* we found a zero */
439 found++;
440 /* move start to the next bit to test */
441 start++;
442 } else {
443 /* got a zero after some ones */
444 found = 1;
445 start = offset + 1;
446 }
447 if (found > best_len) {
448 best_len = found;
449 best_start = start - found;
450 }
451
452 if (found >= wanted)
453 break;
454 }
455
456 if (best_len == 0)
457 return 0;
458
459 if (best_len >= wanted)
460 best_len = wanted;
461
462 *rlen = best_len;
463 *rstart = best_start;
464
465 trace_ocfs2_resmap_find_free_bits_end(best_start, best_len);
466
467 return *rlen;
468}
469
470static void __ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
471 struct ocfs2_alloc_reservation *resv,
472 unsigned int goal, unsigned int wanted)
473{
474 struct rb_root *root = &resmap->m_reservations;
475 unsigned int gap_start, gap_end, gap_len;
476 struct ocfs2_alloc_reservation *prev_resv, *next_resv;
477 struct rb_node *prev, *next;
478 unsigned int cstart, clen;
479 unsigned int best_start = 0, best_len = 0;
480
481 /*
482 * Nasty cases to consider:
483 *
484 * - rbtree is empty
485 * - our window should be first in all reservations
486 * - our window should be last in all reservations
487 * - need to make sure we don't go past end of bitmap
488 */
489 trace_ocfs2_resv_find_window_begin(resv->r_start, ocfs2_resv_end(resv),
490 goal, wanted, RB_EMPTY_ROOT(root));
491
492 assert_spin_locked(&resv_lock);
493
494 if (RB_EMPTY_ROOT(root)) {
495 /*
496 * Easiest case - empty tree. We can just take
497 * whatever window of free bits we want.
498 */
499 clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
500 resmap->m_bitmap_len - goal,
501 &cstart, &clen);
502
503 /*
504 * This should never happen - the local alloc window
505 * will always have free bits when we're called.
506 */
507 BUG_ON(goal == 0 && clen == 0);
508
509 if (clen == 0)
510 return;
511
512 resv->r_start = cstart;
513 resv->r_len = clen;
514
515 ocfs2_resv_insert(resmap, resv);
516 return;
517 }
518
519 prev_resv = ocfs2_find_resv_lhs(resmap, goal);
520
521 if (prev_resv == NULL) {
522 /*
523 * A NULL here means that the search code couldn't
524 * find a window that starts before goal.
525 *
526 * However, we can take the first window after goal,
527 * which is also by definition, the leftmost window in
528 * the entire tree. If we can find free bits in the
529 * gap between goal and the LHS window, then the
530 * reservation can safely be placed there.
531 *
532 * Otherwise we fall back to a linear search, checking
533 * the gaps in between windows for a place to
534 * allocate.
535 */
536
537 next = rb_first(root);
538 next_resv = rb_entry(next, struct ocfs2_alloc_reservation,
539 r_node);
540
541 /*
542 * The search should never return such a window. (see
543 * comment above
544 */
545 if (next_resv->r_start <= goal) {
546 mlog(ML_ERROR, "goal: %u next_resv: start %u len %u\n",
547 goal, next_resv->r_start, next_resv->r_len);
548 ocfs2_dump_resv(resmap);
549 BUG();
550 }
551
552 clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
553 next_resv->r_start - goal,
554 &cstart, &clen);
555 if (clen) {
556 best_len = clen;
557 best_start = cstart;
558 if (best_len == wanted)
559 goto out_insert;
560 }
561
562 prev_resv = next_resv;
563 next_resv = NULL;
564 }
565
566 trace_ocfs2_resv_find_window_prev(prev_resv->r_start,
567 ocfs2_resv_end(prev_resv));
568
569 prev = &prev_resv->r_node;
570
571 /* Now we do a linear search for a window, starting at 'prev_rsv' */
572 while (1) {
573 next = rb_next(prev);
574 if (next) {
575 next_resv = rb_entry(next,
576 struct ocfs2_alloc_reservation,
577 r_node);
578
579 gap_start = ocfs2_resv_end(prev_resv) + 1;
580 gap_end = next_resv->r_start - 1;
581 gap_len = gap_end - gap_start + 1;
582 } else {
583 /*
584 * We're at the rightmost edge of the
585 * tree. See if a reservation between this
586 * window and the end of the bitmap will work.
587 */
588 gap_start = ocfs2_resv_end(prev_resv) + 1;
589 gap_len = resmap->m_bitmap_len - gap_start;
590 gap_end = resmap->m_bitmap_len - 1;
591 }
592
593 trace_ocfs2_resv_find_window_next(next ? next_resv->r_start: -1,
594 next ? ocfs2_resv_end(next_resv) : -1);
595 /*
596 * No need to check this gap if we have already found
597 * a larger region of free bits.
598 */
599 if (gap_len <= best_len)
600 goto next_resv;
601
602 clen = ocfs2_resmap_find_free_bits(resmap, wanted, gap_start,
603 gap_len, &cstart, &clen);
604 if (clen == wanted) {
605 best_len = clen;
606 best_start = cstart;
607 goto out_insert;
608 } else if (clen > best_len) {
609 best_len = clen;
610 best_start = cstart;
611 }
612
613next_resv:
614 if (!next)
615 break;
616
617 prev = next;
618 prev_resv = rb_entry(prev, struct ocfs2_alloc_reservation,
619 r_node);
620 }
621
622out_insert:
623 if (best_len) {
624 resv->r_start = best_start;
625 resv->r_len = best_len;
626 ocfs2_resv_insert(resmap, resv);
627 }
628}
629
630static void ocfs2_cannibalize_resv(struct ocfs2_reservation_map *resmap,
631 struct ocfs2_alloc_reservation *resv,
632 unsigned int wanted)
633{
634 struct ocfs2_alloc_reservation *lru_resv;
635 int tmpwindow = !!(resv->r_flags & OCFS2_RESV_FLAG_TMP);
636 unsigned int min_bits;
637
638 if (!tmpwindow)
639 min_bits = ocfs2_resv_window_bits(resmap, resv) >> 1;
640 else
641 min_bits = wanted; /* We at know the temp window will use all
642 * of these bits */
643
644 /*
645 * Take the first reservation off the LRU as our 'target'. We
646 * don't try to be smart about it. There might be a case for
647 * searching based on size but I don't have enough data to be
648 * sure. --Mark (3/16/2010)
649 */
650 lru_resv = list_first_entry(&resmap->m_lru,
651 struct ocfs2_alloc_reservation, r_lru);
652
653 trace_ocfs2_cannibalize_resv_begin(lru_resv->r_start,
654 lru_resv->r_len,
655 ocfs2_resv_end(lru_resv));
656
657 /*
658 * Cannibalize (some or all) of the target reservation and
659 * feed it to the current window.
660 */
661 if (lru_resv->r_len <= min_bits) {
662 /*
663 * Discard completely if size is less than or equal to a
664 * reasonable threshold - 50% of window bits for non temporary
665 * windows.
666 */
667 resv->r_start = lru_resv->r_start;
668 resv->r_len = lru_resv->r_len;
669
670 __ocfs2_resv_discard(resmap, lru_resv);
671 } else {
672 unsigned int shrink;
673 if (tmpwindow)
674 shrink = min_bits;
675 else
676 shrink = lru_resv->r_len / 2;
677
678 lru_resv->r_len -= shrink;
679
680 resv->r_start = ocfs2_resv_end(lru_resv) + 1;
681 resv->r_len = shrink;
682 }
683
684 trace_ocfs2_cannibalize_resv_end(resv->r_start, ocfs2_resv_end(resv),
685 resv->r_len, resv->r_last_start,
686 resv->r_last_len);
687
688 ocfs2_resv_insert(resmap, resv);
689}
690
691static void ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
692 struct ocfs2_alloc_reservation *resv,
693 unsigned int wanted)
694{
695 unsigned int goal = 0;
696
697 BUG_ON(!ocfs2_resv_empty(resv));
698
699 /*
700 * Begin by trying to get a window as close to the previous
701 * one as possible. Using the most recent allocation as a
702 * start goal makes sense.
703 */
704 if (resv->r_last_len) {
705 goal = resv->r_last_start + resv->r_last_len;
706 if (goal >= resmap->m_bitmap_len)
707 goal = 0;
708 }
709
710 __ocfs2_resv_find_window(resmap, resv, goal, wanted);
711
712 /* Search from last alloc didn't work, try once more from beginning. */
713 if (ocfs2_resv_empty(resv) && goal != 0)
714 __ocfs2_resv_find_window(resmap, resv, 0, wanted);
715
716 if (ocfs2_resv_empty(resv)) {
717 /*
718 * Still empty? Pull oldest one off the LRU, remove it from
719 * tree, put this one in it's place.
720 */
721 ocfs2_cannibalize_resv(resmap, resv, wanted);
722 }
723
724 BUG_ON(ocfs2_resv_empty(resv));
725}
726
727int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
728 struct ocfs2_alloc_reservation *resv,
729 int *cstart, int *clen)
730{
731 if (resv == NULL || ocfs2_resmap_disabled(resmap))
732 return -ENOSPC;
733
734 spin_lock(&resv_lock);
735
736 if (ocfs2_resv_empty(resv)) {
737 /*
738 * We don't want to over-allocate for temporary
739 * windows. Otherwise, we run the risk of fragmenting the
740 * allocation space.
741 */
742 unsigned int wanted = ocfs2_resv_window_bits(resmap, resv);
743
744 if ((resv->r_flags & OCFS2_RESV_FLAG_TMP) || wanted < *clen)
745 wanted = *clen;
746
747 /*
748 * Try to get a window here. If it works, we must fall
749 * through and test the bitmap . This avoids some
750 * ping-ponging of windows due to non-reserved space
751 * being allocation before we initialize a window for
752 * that inode.
753 */
754 ocfs2_resv_find_window(resmap, resv, wanted);
755 trace_ocfs2_resmap_resv_bits(resv->r_start, resv->r_len);
756 }
757
758 BUG_ON(ocfs2_resv_empty(resv));
759
760 *cstart = resv->r_start;
761 *clen = resv->r_len;
762
763 spin_unlock(&resv_lock);
764 return 0;
765}
766
767static void
768 ocfs2_adjust_resv_from_alloc(struct ocfs2_reservation_map *resmap,
769 struct ocfs2_alloc_reservation *resv,
770 unsigned int start, unsigned int end)
771{
772 unsigned int rhs = 0;
773 unsigned int old_end = ocfs2_resv_end(resv);
774
775 BUG_ON(start != resv->r_start || old_end < end);
776
777 /*
778 * Completely used? We can remove it then.
779 */
780 if (old_end == end) {
781 __ocfs2_resv_discard(resmap, resv);
782 return;
783 }
784
785 rhs = old_end - end;
786
787 /*
788 * This should have been trapped above.
789 */
790 BUG_ON(rhs == 0);
791
792 resv->r_start = end + 1;
793 resv->r_len = old_end - resv->r_start + 1;
794}
795
796void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
797 struct ocfs2_alloc_reservation *resv,
798 u32 cstart, u32 clen)
799{
800 unsigned int cend = cstart + clen - 1;
801
802 if (resmap == NULL || ocfs2_resmap_disabled(resmap))
803 return;
804
805 if (resv == NULL)
806 return;
807
808 BUG_ON(cstart != resv->r_start);
809
810 spin_lock(&resv_lock);
811
812 trace_ocfs2_resmap_claimed_bits_begin(cstart, cend, clen, resv->r_start,
813 ocfs2_resv_end(resv), resv->r_len,
814 resv->r_last_start,
815 resv->r_last_len);
816
817 BUG_ON(cstart < resv->r_start);
818 BUG_ON(cstart > ocfs2_resv_end(resv));
819 BUG_ON(cend > ocfs2_resv_end(resv));
820
821 ocfs2_adjust_resv_from_alloc(resmap, resv, cstart, cend);
822 resv->r_last_start = cstart;
823 resv->r_last_len = clen;
824
825 /*
826 * May have been discarded above from
827 * ocfs2_adjust_resv_from_alloc().
828 */
829 if (!ocfs2_resv_empty(resv))
830 ocfs2_resv_mark_lru(resmap, resv);
831
832 trace_ocfs2_resmap_claimed_bits_end(resv->r_start, ocfs2_resv_end(resv),
833 resv->r_len, resv->r_last_start,
834 resv->r_last_len);
835
836 ocfs2_check_resmap(resmap);
837
838 spin_unlock(&resv_lock);
839}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * reservations.c
4 *
5 * Allocation reservations implementation
6 *
7 * Some code borrowed from fs/ext3/balloc.c and is:
8 *
9 * Copyright (C) 1992, 1993, 1994, 1995
10 * Remy Card (card@masi.ibp.fr)
11 * Laboratoire MASI - Institut Blaise Pascal
12 * Universite Pierre et Marie Curie (Paris VI)
13 *
14 * The rest is copyright (C) 2010 Novell. All rights reserved.
15 */
16
17#include <linux/fs.h>
18#include <linux/types.h>
19#include <linux/highmem.h>
20#include <linux/bitops.h>
21#include <linux/list.h>
22
23#include <cluster/masklog.h>
24
25#include "ocfs2.h"
26#include "ocfs2_trace.h"
27
28#ifdef CONFIG_OCFS2_DEBUG_FS
29#define OCFS2_CHECK_RESERVATIONS
30#endif
31
32static DEFINE_SPINLOCK(resv_lock);
33
34int ocfs2_dir_resv_allowed(struct ocfs2_super *osb)
35{
36 return (osb->osb_resv_level && osb->osb_dir_resv_level);
37}
38
39static unsigned int ocfs2_resv_window_bits(struct ocfs2_reservation_map *resmap,
40 struct ocfs2_alloc_reservation *resv)
41{
42 struct ocfs2_super *osb = resmap->m_osb;
43 unsigned int bits;
44
45 if (!(resv->r_flags & OCFS2_RESV_FLAG_DIR)) {
46 /* 8, 16, 32, 64, 128, 256, 512, 1024 */
47 bits = 4 << osb->osb_resv_level;
48 } else {
49 bits = 4 << osb->osb_dir_resv_level;
50 }
51 return bits;
52}
53
54static inline unsigned int ocfs2_resv_end(struct ocfs2_alloc_reservation *resv)
55{
56 if (resv->r_len)
57 return resv->r_start + resv->r_len - 1;
58 return resv->r_start;
59}
60
61static inline int ocfs2_resv_empty(struct ocfs2_alloc_reservation *resv)
62{
63 return !!(resv->r_len == 0);
64}
65
66static inline int ocfs2_resmap_disabled(struct ocfs2_reservation_map *resmap)
67{
68 if (resmap->m_osb->osb_resv_level == 0)
69 return 1;
70 return 0;
71}
72
73static void ocfs2_dump_resv(struct ocfs2_reservation_map *resmap)
74{
75 struct ocfs2_super *osb = resmap->m_osb;
76 struct rb_node *node;
77 struct ocfs2_alloc_reservation *resv;
78 int i = 0;
79
80 mlog(ML_NOTICE, "Dumping resmap for device %s. Bitmap length: %u\n",
81 osb->dev_str, resmap->m_bitmap_len);
82
83 node = rb_first(&resmap->m_reservations);
84 while (node) {
85 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
86
87 mlog(ML_NOTICE, "start: %u\tend: %u\tlen: %u\tlast_start: %u"
88 "\tlast_len: %u\n", resv->r_start,
89 ocfs2_resv_end(resv), resv->r_len, resv->r_last_start,
90 resv->r_last_len);
91
92 node = rb_next(node);
93 i++;
94 }
95
96 mlog(ML_NOTICE, "%d reservations found. LRU follows\n", i);
97
98 i = 0;
99 list_for_each_entry(resv, &resmap->m_lru, r_lru) {
100 mlog(ML_NOTICE, "LRU(%d) start: %u\tend: %u\tlen: %u\t"
101 "last_start: %u\tlast_len: %u\n", i, resv->r_start,
102 ocfs2_resv_end(resv), resv->r_len, resv->r_last_start,
103 resv->r_last_len);
104
105 i++;
106 }
107}
108
109#ifdef OCFS2_CHECK_RESERVATIONS
110static int ocfs2_validate_resmap_bits(struct ocfs2_reservation_map *resmap,
111 int i,
112 struct ocfs2_alloc_reservation *resv)
113{
114 char *disk_bitmap = resmap->m_disk_bitmap;
115 unsigned int start = resv->r_start;
116 unsigned int end = ocfs2_resv_end(resv);
117
118 while (start <= end) {
119 if (ocfs2_test_bit(start, disk_bitmap)) {
120 mlog(ML_ERROR,
121 "reservation %d covers an allocated area "
122 "starting at bit %u!\n", i, start);
123 return 1;
124 }
125
126 start++;
127 }
128 return 0;
129}
130
131static void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap)
132{
133 unsigned int off = 0;
134 int i = 0;
135 struct rb_node *node;
136 struct ocfs2_alloc_reservation *resv;
137
138 node = rb_first(&resmap->m_reservations);
139 while (node) {
140 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
141
142 if (i > 0 && resv->r_start <= off) {
143 mlog(ML_ERROR, "reservation %d has bad start off!\n",
144 i);
145 goto bad;
146 }
147
148 if (resv->r_len == 0) {
149 mlog(ML_ERROR, "reservation %d has no length!\n",
150 i);
151 goto bad;
152 }
153
154 if (resv->r_start > ocfs2_resv_end(resv)) {
155 mlog(ML_ERROR, "reservation %d has invalid range!\n",
156 i);
157 goto bad;
158 }
159
160 if (ocfs2_resv_end(resv) >= resmap->m_bitmap_len) {
161 mlog(ML_ERROR, "reservation %d extends past bitmap!\n",
162 i);
163 goto bad;
164 }
165
166 if (ocfs2_validate_resmap_bits(resmap, i, resv))
167 goto bad;
168
169 off = ocfs2_resv_end(resv);
170 node = rb_next(node);
171
172 i++;
173 }
174 return;
175
176bad:
177 ocfs2_dump_resv(resmap);
178 BUG();
179}
180#else
181static inline void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap)
182{
183
184}
185#endif
186
187void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv)
188{
189 memset(resv, 0, sizeof(*resv));
190 INIT_LIST_HEAD(&resv->r_lru);
191}
192
193void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv,
194 unsigned int flags)
195{
196 BUG_ON(flags & ~OCFS2_RESV_TYPES);
197
198 resv->r_flags |= flags;
199}
200
201void ocfs2_resmap_init(struct ocfs2_super *osb,
202 struct ocfs2_reservation_map *resmap)
203{
204 memset(resmap, 0, sizeof(*resmap));
205
206 resmap->m_osb = osb;
207 resmap->m_reservations = RB_ROOT;
208 /* m_bitmap_len is initialized to zero by the above memset. */
209 INIT_LIST_HEAD(&resmap->m_lru);
210}
211
212static void ocfs2_resv_mark_lru(struct ocfs2_reservation_map *resmap,
213 struct ocfs2_alloc_reservation *resv)
214{
215 assert_spin_locked(&resv_lock);
216
217 if (!list_empty(&resv->r_lru))
218 list_del_init(&resv->r_lru);
219
220 list_add_tail(&resv->r_lru, &resmap->m_lru);
221}
222
223static void __ocfs2_resv_trunc(struct ocfs2_alloc_reservation *resv)
224{
225 resv->r_len = 0;
226 resv->r_start = 0;
227}
228
229static void ocfs2_resv_remove(struct ocfs2_reservation_map *resmap,
230 struct ocfs2_alloc_reservation *resv)
231{
232 if (resv->r_flags & OCFS2_RESV_FLAG_INUSE) {
233 list_del_init(&resv->r_lru);
234 rb_erase(&resv->r_node, &resmap->m_reservations);
235 resv->r_flags &= ~OCFS2_RESV_FLAG_INUSE;
236 }
237}
238
239static void __ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
240 struct ocfs2_alloc_reservation *resv)
241{
242 assert_spin_locked(&resv_lock);
243
244 __ocfs2_resv_trunc(resv);
245 /*
246 * last_len and last_start no longer make sense if
247 * we're changing the range of our allocations.
248 */
249 resv->r_last_len = resv->r_last_start = 0;
250
251 ocfs2_resv_remove(resmap, resv);
252}
253
254/* does nothing if 'resv' is null */
255void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
256 struct ocfs2_alloc_reservation *resv)
257{
258 if (resv) {
259 spin_lock(&resv_lock);
260 __ocfs2_resv_discard(resmap, resv);
261 spin_unlock(&resv_lock);
262 }
263}
264
265static void ocfs2_resmap_clear_all_resv(struct ocfs2_reservation_map *resmap)
266{
267 struct rb_node *node;
268 struct ocfs2_alloc_reservation *resv;
269
270 assert_spin_locked(&resv_lock);
271
272 while ((node = rb_last(&resmap->m_reservations)) != NULL) {
273 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
274
275 __ocfs2_resv_discard(resmap, resv);
276 }
277}
278
279void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
280 unsigned int clen, char *disk_bitmap)
281{
282 if (ocfs2_resmap_disabled(resmap))
283 return;
284
285 spin_lock(&resv_lock);
286
287 ocfs2_resmap_clear_all_resv(resmap);
288 resmap->m_bitmap_len = clen;
289 resmap->m_disk_bitmap = disk_bitmap;
290
291 spin_unlock(&resv_lock);
292}
293
294void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap)
295{
296 /* Does nothing for now. Keep this around for API symmetry */
297}
298
299static void ocfs2_resv_insert(struct ocfs2_reservation_map *resmap,
300 struct ocfs2_alloc_reservation *new)
301{
302 struct rb_root *root = &resmap->m_reservations;
303 struct rb_node *parent = NULL;
304 struct rb_node **p = &root->rb_node;
305 struct ocfs2_alloc_reservation *tmp;
306
307 assert_spin_locked(&resv_lock);
308
309 trace_ocfs2_resv_insert(new->r_start, new->r_len);
310
311 while (*p) {
312 parent = *p;
313
314 tmp = rb_entry(parent, struct ocfs2_alloc_reservation, r_node);
315
316 if (new->r_start < tmp->r_start) {
317 p = &(*p)->rb_left;
318
319 /*
320 * This is a good place to check for
321 * overlapping reservations.
322 */
323 BUG_ON(ocfs2_resv_end(new) >= tmp->r_start);
324 } else if (new->r_start > ocfs2_resv_end(tmp)) {
325 p = &(*p)->rb_right;
326 } else {
327 /* This should never happen! */
328 mlog(ML_ERROR, "Duplicate reservation window!\n");
329 BUG();
330 }
331 }
332
333 rb_link_node(&new->r_node, parent, p);
334 rb_insert_color(&new->r_node, root);
335 new->r_flags |= OCFS2_RESV_FLAG_INUSE;
336
337 ocfs2_resv_mark_lru(resmap, new);
338
339 ocfs2_check_resmap(resmap);
340}
341
342/**
343 * ocfs2_find_resv_lhs() - find the window which contains goal
344 * @resmap: reservation map to search
345 * @goal: which bit to search for
346 *
347 * If a window containing that goal is not found, we return the window
348 * which comes before goal. Returns NULL on empty rbtree or no window
349 * before goal.
350 */
351static struct ocfs2_alloc_reservation *
352ocfs2_find_resv_lhs(struct ocfs2_reservation_map *resmap, unsigned int goal)
353{
354 struct ocfs2_alloc_reservation *resv = NULL;
355 struct ocfs2_alloc_reservation *prev_resv = NULL;
356 struct rb_node *node = resmap->m_reservations.rb_node;
357
358 assert_spin_locked(&resv_lock);
359
360 if (!node)
361 return NULL;
362
363 node = rb_first(&resmap->m_reservations);
364 while (node) {
365 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
366
367 if (resv->r_start <= goal && ocfs2_resv_end(resv) >= goal)
368 break;
369
370 /* Check if we overshot the reservation just before goal? */
371 if (resv->r_start > goal) {
372 resv = prev_resv;
373 break;
374 }
375
376 prev_resv = resv;
377 node = rb_next(node);
378 }
379
380 return resv;
381}
382
383/*
384 * We are given a range within the bitmap, which corresponds to a gap
385 * inside the reservations tree (search_start, search_len). The range
386 * can be anything from the whole bitmap, to a gap between
387 * reservations.
388 *
389 * The start value of *rstart is insignificant.
390 *
391 * This function searches the bitmap range starting at search_start
392 * with length search_len for a set of contiguous free bits. We try
393 * to find up to 'wanted' bits, but can sometimes return less.
394 *
395 * Returns the length of allocation, 0 if no free bits are found.
396 *
397 * *cstart and *clen will also be populated with the result.
398 */
399static int ocfs2_resmap_find_free_bits(struct ocfs2_reservation_map *resmap,
400 unsigned int wanted,
401 unsigned int search_start,
402 unsigned int search_len,
403 unsigned int *rstart,
404 unsigned int *rlen)
405{
406 void *bitmap = resmap->m_disk_bitmap;
407 unsigned int best_start, best_len = 0;
408 int offset, start, found;
409
410 trace_ocfs2_resmap_find_free_bits_begin(search_start, search_len,
411 wanted, resmap->m_bitmap_len);
412
413 found = best_start = best_len = 0;
414
415 start = search_start;
416 while ((offset = ocfs2_find_next_zero_bit(bitmap, resmap->m_bitmap_len,
417 start)) < resmap->m_bitmap_len) {
418 /* Search reached end of the region */
419 if (offset >= (search_start + search_len))
420 break;
421
422 if (offset == start) {
423 /* we found a zero */
424 found++;
425 /* move start to the next bit to test */
426 start++;
427 } else {
428 /* got a zero after some ones */
429 found = 1;
430 start = offset + 1;
431 }
432 if (found > best_len) {
433 best_len = found;
434 best_start = start - found;
435 }
436
437 if (found >= wanted)
438 break;
439 }
440
441 if (best_len == 0)
442 return 0;
443
444 if (best_len >= wanted)
445 best_len = wanted;
446
447 *rlen = best_len;
448 *rstart = best_start;
449
450 trace_ocfs2_resmap_find_free_bits_end(best_start, best_len);
451
452 return *rlen;
453}
454
455static void __ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
456 struct ocfs2_alloc_reservation *resv,
457 unsigned int goal, unsigned int wanted)
458{
459 struct rb_root *root = &resmap->m_reservations;
460 unsigned int gap_start, gap_end, gap_len;
461 struct ocfs2_alloc_reservation *prev_resv, *next_resv;
462 struct rb_node *prev, *next;
463 unsigned int cstart, clen;
464 unsigned int best_start = 0, best_len = 0;
465
466 /*
467 * Nasty cases to consider:
468 *
469 * - rbtree is empty
470 * - our window should be first in all reservations
471 * - our window should be last in all reservations
472 * - need to make sure we don't go past end of bitmap
473 */
474 trace_ocfs2_resv_find_window_begin(resv->r_start, ocfs2_resv_end(resv),
475 goal, wanted, RB_EMPTY_ROOT(root));
476
477 assert_spin_locked(&resv_lock);
478
479 if (RB_EMPTY_ROOT(root)) {
480 /*
481 * Easiest case - empty tree. We can just take
482 * whatever window of free bits we want.
483 */
484 clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
485 resmap->m_bitmap_len - goal,
486 &cstart, &clen);
487
488 /*
489 * This should never happen - the local alloc window
490 * will always have free bits when we're called.
491 */
492 BUG_ON(goal == 0 && clen == 0);
493
494 if (clen == 0)
495 return;
496
497 resv->r_start = cstart;
498 resv->r_len = clen;
499
500 ocfs2_resv_insert(resmap, resv);
501 return;
502 }
503
504 prev_resv = ocfs2_find_resv_lhs(resmap, goal);
505
506 if (prev_resv == NULL) {
507 /*
508 * A NULL here means that the search code couldn't
509 * find a window that starts before goal.
510 *
511 * However, we can take the first window after goal,
512 * which is also by definition, the leftmost window in
513 * the entire tree. If we can find free bits in the
514 * gap between goal and the LHS window, then the
515 * reservation can safely be placed there.
516 *
517 * Otherwise we fall back to a linear search, checking
518 * the gaps in between windows for a place to
519 * allocate.
520 */
521
522 next = rb_first(root);
523 next_resv = rb_entry(next, struct ocfs2_alloc_reservation,
524 r_node);
525
526 /*
527 * The search should never return such a window. (see
528 * comment above
529 */
530 if (next_resv->r_start <= goal) {
531 mlog(ML_ERROR, "goal: %u next_resv: start %u len %u\n",
532 goal, next_resv->r_start, next_resv->r_len);
533 ocfs2_dump_resv(resmap);
534 BUG();
535 }
536
537 clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
538 next_resv->r_start - goal,
539 &cstart, &clen);
540 if (clen) {
541 best_len = clen;
542 best_start = cstart;
543 if (best_len == wanted)
544 goto out_insert;
545 }
546
547 prev_resv = next_resv;
548 next_resv = NULL;
549 }
550
551 trace_ocfs2_resv_find_window_prev(prev_resv->r_start,
552 ocfs2_resv_end(prev_resv));
553
554 prev = &prev_resv->r_node;
555
556 /* Now we do a linear search for a window, starting at 'prev_rsv' */
557 while (1) {
558 next = rb_next(prev);
559 if (next) {
560 next_resv = rb_entry(next,
561 struct ocfs2_alloc_reservation,
562 r_node);
563
564 gap_start = ocfs2_resv_end(prev_resv) + 1;
565 gap_end = next_resv->r_start - 1;
566 gap_len = gap_end - gap_start + 1;
567 } else {
568 /*
569 * We're at the rightmost edge of the
570 * tree. See if a reservation between this
571 * window and the end of the bitmap will work.
572 */
573 gap_start = ocfs2_resv_end(prev_resv) + 1;
574 gap_len = resmap->m_bitmap_len - gap_start;
575 gap_end = resmap->m_bitmap_len - 1;
576 }
577
578 trace_ocfs2_resv_find_window_next(next ? next_resv->r_start: -1,
579 next ? ocfs2_resv_end(next_resv) : -1);
580 /*
581 * No need to check this gap if we have already found
582 * a larger region of free bits.
583 */
584 if (gap_len <= best_len)
585 goto next_resv;
586
587 clen = ocfs2_resmap_find_free_bits(resmap, wanted, gap_start,
588 gap_len, &cstart, &clen);
589 if (clen == wanted) {
590 best_len = clen;
591 best_start = cstart;
592 goto out_insert;
593 } else if (clen > best_len) {
594 best_len = clen;
595 best_start = cstart;
596 }
597
598next_resv:
599 if (!next)
600 break;
601
602 prev = next;
603 prev_resv = rb_entry(prev, struct ocfs2_alloc_reservation,
604 r_node);
605 }
606
607out_insert:
608 if (best_len) {
609 resv->r_start = best_start;
610 resv->r_len = best_len;
611 ocfs2_resv_insert(resmap, resv);
612 }
613}
614
615static void ocfs2_cannibalize_resv(struct ocfs2_reservation_map *resmap,
616 struct ocfs2_alloc_reservation *resv,
617 unsigned int wanted)
618{
619 struct ocfs2_alloc_reservation *lru_resv;
620 int tmpwindow = !!(resv->r_flags & OCFS2_RESV_FLAG_TMP);
621 unsigned int min_bits;
622
623 if (!tmpwindow)
624 min_bits = ocfs2_resv_window_bits(resmap, resv) >> 1;
625 else
626 min_bits = wanted; /* We at know the temp window will use all
627 * of these bits */
628
629 /*
630 * Take the first reservation off the LRU as our 'target'. We
631 * don't try to be smart about it. There might be a case for
632 * searching based on size but I don't have enough data to be
633 * sure. --Mark (3/16/2010)
634 */
635 lru_resv = list_first_entry(&resmap->m_lru,
636 struct ocfs2_alloc_reservation, r_lru);
637
638 trace_ocfs2_cannibalize_resv_begin(lru_resv->r_start,
639 lru_resv->r_len,
640 ocfs2_resv_end(lru_resv));
641
642 /*
643 * Cannibalize (some or all) of the target reservation and
644 * feed it to the current window.
645 */
646 if (lru_resv->r_len <= min_bits) {
647 /*
648 * Discard completely if size is less than or equal to a
649 * reasonable threshold - 50% of window bits for non temporary
650 * windows.
651 */
652 resv->r_start = lru_resv->r_start;
653 resv->r_len = lru_resv->r_len;
654
655 __ocfs2_resv_discard(resmap, lru_resv);
656 } else {
657 unsigned int shrink;
658 if (tmpwindow)
659 shrink = min_bits;
660 else
661 shrink = lru_resv->r_len / 2;
662
663 lru_resv->r_len -= shrink;
664
665 resv->r_start = ocfs2_resv_end(lru_resv) + 1;
666 resv->r_len = shrink;
667 }
668
669 trace_ocfs2_cannibalize_resv_end(resv->r_start, ocfs2_resv_end(resv),
670 resv->r_len, resv->r_last_start,
671 resv->r_last_len);
672
673 ocfs2_resv_insert(resmap, resv);
674}
675
676static void ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
677 struct ocfs2_alloc_reservation *resv,
678 unsigned int wanted)
679{
680 unsigned int goal = 0;
681
682 BUG_ON(!ocfs2_resv_empty(resv));
683
684 /*
685 * Begin by trying to get a window as close to the previous
686 * one as possible. Using the most recent allocation as a
687 * start goal makes sense.
688 */
689 if (resv->r_last_len) {
690 goal = resv->r_last_start + resv->r_last_len;
691 if (goal >= resmap->m_bitmap_len)
692 goal = 0;
693 }
694
695 __ocfs2_resv_find_window(resmap, resv, goal, wanted);
696
697 /* Search from last alloc didn't work, try once more from beginning. */
698 if (ocfs2_resv_empty(resv) && goal != 0)
699 __ocfs2_resv_find_window(resmap, resv, 0, wanted);
700
701 if (ocfs2_resv_empty(resv)) {
702 /*
703 * Still empty? Pull oldest one off the LRU, remove it from
704 * tree, put this one in it's place.
705 */
706 ocfs2_cannibalize_resv(resmap, resv, wanted);
707 }
708
709 BUG_ON(ocfs2_resv_empty(resv));
710}
711
712int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
713 struct ocfs2_alloc_reservation *resv,
714 int *cstart, int *clen)
715{
716 if (resv == NULL || ocfs2_resmap_disabled(resmap))
717 return -ENOSPC;
718
719 spin_lock(&resv_lock);
720
721 if (ocfs2_resv_empty(resv)) {
722 /*
723 * We don't want to over-allocate for temporary
724 * windows. Otherwise, we run the risk of fragmenting the
725 * allocation space.
726 */
727 unsigned int wanted = ocfs2_resv_window_bits(resmap, resv);
728
729 if ((resv->r_flags & OCFS2_RESV_FLAG_TMP) || wanted < *clen)
730 wanted = *clen;
731
732 /*
733 * Try to get a window here. If it works, we must fall
734 * through and test the bitmap . This avoids some
735 * ping-ponging of windows due to non-reserved space
736 * being allocation before we initialize a window for
737 * that inode.
738 */
739 ocfs2_resv_find_window(resmap, resv, wanted);
740 trace_ocfs2_resmap_resv_bits(resv->r_start, resv->r_len);
741 }
742
743 BUG_ON(ocfs2_resv_empty(resv));
744
745 *cstart = resv->r_start;
746 *clen = resv->r_len;
747
748 spin_unlock(&resv_lock);
749 return 0;
750}
751
752static void
753 ocfs2_adjust_resv_from_alloc(struct ocfs2_reservation_map *resmap,
754 struct ocfs2_alloc_reservation *resv,
755 unsigned int start, unsigned int end)
756{
757 unsigned int rhs = 0;
758 unsigned int old_end = ocfs2_resv_end(resv);
759
760 BUG_ON(start != resv->r_start || old_end < end);
761
762 /*
763 * Completely used? We can remove it then.
764 */
765 if (old_end == end) {
766 __ocfs2_resv_discard(resmap, resv);
767 return;
768 }
769
770 rhs = old_end - end;
771
772 /*
773 * This should have been trapped above.
774 */
775 BUG_ON(rhs == 0);
776
777 resv->r_start = end + 1;
778 resv->r_len = old_end - resv->r_start + 1;
779}
780
781void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
782 struct ocfs2_alloc_reservation *resv,
783 u32 cstart, u32 clen)
784{
785 unsigned int cend = cstart + clen - 1;
786
787 if (resmap == NULL || ocfs2_resmap_disabled(resmap))
788 return;
789
790 if (resv == NULL)
791 return;
792
793 BUG_ON(cstart != resv->r_start);
794
795 spin_lock(&resv_lock);
796
797 trace_ocfs2_resmap_claimed_bits_begin(cstart, cend, clen, resv->r_start,
798 ocfs2_resv_end(resv), resv->r_len,
799 resv->r_last_start,
800 resv->r_last_len);
801
802 BUG_ON(cstart < resv->r_start);
803 BUG_ON(cstart > ocfs2_resv_end(resv));
804 BUG_ON(cend > ocfs2_resv_end(resv));
805
806 ocfs2_adjust_resv_from_alloc(resmap, resv, cstart, cend);
807 resv->r_last_start = cstart;
808 resv->r_last_len = clen;
809
810 /*
811 * May have been discarded above from
812 * ocfs2_adjust_resv_from_alloc().
813 */
814 if (!ocfs2_resv_empty(resv))
815 ocfs2_resv_mark_lru(resmap, resv);
816
817 trace_ocfs2_resmap_claimed_bits_end(resv->r_start, ocfs2_resv_end(resv),
818 resv->r_len, resv->r_last_start,
819 resv->r_last_len);
820
821 ocfs2_check_resmap(resmap);
822
823 spin_unlock(&resv_lock);
824}