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