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