blob: 3e78db361bc70b3ffc327a6f21b6d4580305d0eb [file] [log] [blame]
Mark Fashehd02f00c2009-12-07 13:10:48 -08001/* -*- 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>
Mark Fashehd02f00c2009-12-07 13:10:48 -080029#include <linux/highmem.h>
30#include <linux/bitops.h>
31#include <linux/list.h>
32
33#define MLOG_MASK_PREFIX ML_RESERVATIONS
34#include <cluster/masklog.h>
35
36#include "ocfs2.h"
37
38#ifdef CONFIG_OCFS2_DEBUG_FS
39#define OCFS2_CHECK_RESERVATIONS
40#endif
41
42DEFINE_SPINLOCK(resv_lock);
43
44#define OCFS2_MIN_RESV_WINDOW_BITS 8
45#define OCFS2_MAX_RESV_WINDOW_BITS 1024
Mark Fasheh83f92312010-04-05 18:17:16 -070046
47int ocfs2_dir_resv_allowed(struct ocfs2_super *osb)
48{
49 return (osb->osb_resv_level && osb->osb_dir_resv_level);
50}
Mark Fashehd02f00c2009-12-07 13:10:48 -080051
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
Mark Fashehe3b4a972009-12-07 13:16:07 -080058 if (!(resv->r_flags & OCFS2_RESV_FLAG_DIR)) {
59 /* 8, 16, 32, 64, 128, 256, 512, 1024 */
60 bits = 4 << osb->osb_resv_level;
Mark Fashehb07f8f22010-04-05 18:17:15 -070061 } else {
Mark Fasheh83f92312010-04-05 18:17:16 -070062 bits = 4 << osb->osb_dir_resv_level;
Mark Fashehb07f8f22010-04-05 18:17:15 -070063 }
Mark Fashehd02f00c2009-12-07 13:10:48 -080064 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 mlog(0, "Insert reservation start: %u len: %u\n", new->r_start,
325 new->r_len);
326
327 while (*p) {
328 parent = *p;
329
330 tmp = rb_entry(parent, struct ocfs2_alloc_reservation, r_node);
331
332 if (new->r_start < tmp->r_start) {
333 p = &(*p)->rb_left;
334
335 /*
336 * This is a good place to check for
337 * overlapping reservations.
338 */
339 BUG_ON(ocfs2_resv_end(new) >= tmp->r_start);
340 } else if (new->r_start > ocfs2_resv_end(tmp)) {
341 p = &(*p)->rb_right;
342 } else {
343 /* This should never happen! */
344 mlog(ML_ERROR, "Duplicate reservation window!\n");
345 BUG();
346 }
347 }
348
349 rb_link_node(&new->r_node, parent, p);
350 rb_insert_color(&new->r_node, root);
351 new->r_flags |= OCFS2_RESV_FLAG_INUSE;
352
353 ocfs2_resv_mark_lru(resmap, new);
354
355 ocfs2_check_resmap(resmap);
356}
357
358/**
359 * ocfs2_find_resv_lhs() - find the window which contains goal
360 * @resmap: reservation map to search
361 * @goal: which bit to search for
362 *
363 * If a window containing that goal is not found, we return the window
364 * which comes before goal. Returns NULL on empty rbtree or no window
365 * before goal.
366 */
367static struct ocfs2_alloc_reservation *
368ocfs2_find_resv_lhs(struct ocfs2_reservation_map *resmap, unsigned int goal)
369{
370 struct ocfs2_alloc_reservation *resv = NULL;
371 struct ocfs2_alloc_reservation *prev_resv = NULL;
372 struct rb_node *node = resmap->m_reservations.rb_node;
Mark Fashehd02f00c2009-12-07 13:10:48 -0800373
374 assert_spin_locked(&resv_lock);
375
376 if (!node)
377 return NULL;
378
379 node = rb_first(&resmap->m_reservations);
380 while (node) {
381 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
382
383 if (resv->r_start <= goal && ocfs2_resv_end(resv) >= goal)
384 break;
385
386 /* Check if we overshot the reservation just before goal? */
387 if (resv->r_start > goal) {
388 resv = prev_resv;
389 break;
390 }
391
392 prev_resv = resv;
Mark Fashehd02f00c2009-12-07 13:10:48 -0800393 node = rb_next(node);
394 }
395
396 return resv;
397}
398
399/*
400 * We are given a range within the bitmap, which corresponds to a gap
401 * inside the reservations tree (search_start, search_len). The range
402 * can be anything from the whole bitmap, to a gap between
403 * reservations.
404 *
405 * The start value of *rstart is insignificant.
406 *
407 * This function searches the bitmap range starting at search_start
Tao Mab0655562010-04-08 16:33:02 +0800408 * with length search_len for a set of contiguous free bits. We try
Mark Fashehd02f00c2009-12-07 13:10:48 -0800409 * to find up to 'wanted' bits, but can sometimes return less.
410 *
411 * Returns the length of allocation, 0 if no free bits are found.
412 *
413 * *cstart and *clen will also be populated with the result.
414 */
415static int ocfs2_resmap_find_free_bits(struct ocfs2_reservation_map *resmap,
416 unsigned int wanted,
417 unsigned int search_start,
418 unsigned int search_len,
419 unsigned int *rstart,
420 unsigned int *rlen)
421{
422 void *bitmap = resmap->m_disk_bitmap;
423 unsigned int best_start, best_len = 0;
424 int offset, start, found;
425
426 mlog(0, "Find %u bits within range (%u, len %u) resmap len: %u\n",
427 wanted, search_start, search_len, resmap->m_bitmap_len);
428
429 found = best_start = best_len = 0;
430
431 start = search_start;
432 while ((offset = ocfs2_find_next_zero_bit(bitmap, resmap->m_bitmap_len,
433 start)) != -1) {
434 /* Search reached end of the region */
435 if (offset >= (search_start + search_len))
436 break;
437
438 if (offset == start) {
439 /* we found a zero */
440 found++;
441 /* move start to the next bit to test */
442 start++;
443 } else {
444 /* got a zero after some ones */
445 found = 1;
446 start = offset + 1;
447 }
448 if (found > best_len) {
449 best_len = found;
450 best_start = start - found;
451 }
452
453 if (found >= wanted)
454 break;
455 }
456
457 if (best_len == 0)
458 return 0;
459
460 if (best_len >= wanted)
461 best_len = wanted;
462
463 *rlen = best_len;
464 *rstart = best_start;
465
466 mlog(0, "Found start: %u len: %u\n", best_start, best_len);
467
468 return *rlen;
469}
470
471static void __ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
472 struct ocfs2_alloc_reservation *resv,
473 unsigned int goal, unsigned int wanted)
474{
475 struct rb_root *root = &resmap->m_reservations;
476 unsigned int gap_start, gap_end, gap_len;
477 struct ocfs2_alloc_reservation *prev_resv, *next_resv;
478 struct rb_node *prev, *next;
479 unsigned int cstart, clen;
480 unsigned int best_start = 0, best_len = 0;
481
482 /*
483 * Nasty cases to consider:
484 *
485 * - rbtree is empty
486 * - our window should be first in all reservations
487 * - our window should be last in all reservations
488 * - need to make sure we don't go past end of bitmap
489 */
490
491 mlog(0, "resv start: %u resv end: %u goal: %u wanted: %u\n",
492 resv->r_start, ocfs2_resv_end(resv), goal, wanted);
493
494 assert_spin_locked(&resv_lock);
495
496 if (RB_EMPTY_ROOT(root)) {
497 /*
498 * Easiest case - empty tree. We can just take
499 * whatever window of free bits we want.
500 */
501
502 mlog(0, "Empty root\n");
503
504 clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
505 resmap->m_bitmap_len - goal,
506 &cstart, &clen);
507
508 /*
509 * This should never happen - the local alloc window
510 * will always have free bits when we're called.
511 */
512 BUG_ON(goal == 0 && clen == 0);
513
514 if (clen == 0)
515 return;
516
517 resv->r_start = cstart;
518 resv->r_len = clen;
519
520 ocfs2_resv_insert(resmap, resv);
521 return;
522 }
523
524 prev_resv = ocfs2_find_resv_lhs(resmap, goal);
525
526 if (prev_resv == NULL) {
527 mlog(0, "Goal on LHS of leftmost window\n");
528
529 /*
530 * A NULL here means that the search code couldn't
531 * find a window that starts before goal.
532 *
533 * However, we can take the first window after goal,
534 * which is also by definition, the leftmost window in
535 * the entire tree. If we can find free bits in the
536 * gap between goal and the LHS window, then the
537 * reservation can safely be placed there.
538 *
539 * Otherwise we fall back to a linear search, checking
540 * the gaps in between windows for a place to
541 * allocate.
542 */
543
544 next = rb_first(root);
545 next_resv = rb_entry(next, struct ocfs2_alloc_reservation,
546 r_node);
547
548 /*
549 * The search should never return such a window. (see
550 * comment above
551 */
552 if (next_resv->r_start <= goal) {
553 mlog(ML_ERROR, "goal: %u next_resv: start %u len %u\n",
554 goal, next_resv->r_start, next_resv->r_len);
555 ocfs2_dump_resv(resmap);
556 BUG();
557 }
558
559 clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
560 next_resv->r_start - goal,
561 &cstart, &clen);
562 if (clen) {
563 best_len = clen;
564 best_start = cstart;
565 if (best_len == wanted)
566 goto out_insert;
567 }
568
569 prev_resv = next_resv;
570 next_resv = NULL;
571 }
572
573 prev = &prev_resv->r_node;
574
575 /* Now we do a linear search for a window, starting at 'prev_rsv' */
576 while (1) {
577 next = rb_next(prev);
578 if (next) {
579 mlog(0, "One more resv found in linear search\n");
580 next_resv = rb_entry(next,
581 struct ocfs2_alloc_reservation,
582 r_node);
583
584 gap_start = ocfs2_resv_end(prev_resv) + 1;
585 gap_end = next_resv->r_start - 1;
586 gap_len = gap_end - gap_start + 1;
587 } else {
588 mlog(0, "No next node\n");
589 /*
590 * We're at the rightmost edge of the
591 * tree. See if a reservation between this
592 * window and the end of the bitmap will work.
593 */
594 gap_start = ocfs2_resv_end(prev_resv) + 1;
595 gap_len = resmap->m_bitmap_len - gap_start;
596 gap_end = resmap->m_bitmap_len - 1;
597 }
598
599 /*
600 * No need to check this gap if we have already found
601 * a larger region of free bits.
602 */
603 if (gap_len <= best_len)
604 goto next_resv;
605
606 clen = ocfs2_resmap_find_free_bits(resmap, wanted, gap_start,
607 gap_len, &cstart, &clen);
608 if (clen == wanted) {
609 best_len = clen;
610 best_start = cstart;
611 goto out_insert;
612 } else if (clen > best_len) {
613 best_len = clen;
614 best_start = cstart;
615 }
616
617next_resv:
618 if (!next)
619 break;
620
621 prev = next;
622 prev_resv = rb_entry(prev, struct ocfs2_alloc_reservation,
623 r_node);
624 }
625
626out_insert:
627 if (best_len) {
628 resv->r_start = best_start;
629 resv->r_len = best_len;
630 ocfs2_resv_insert(resmap, resv);
631 }
632}
633
634static void ocfs2_cannibalize_resv(struct ocfs2_reservation_map *resmap,
635 struct ocfs2_alloc_reservation *resv,
636 unsigned int wanted)
637{
638 struct ocfs2_alloc_reservation *lru_resv;
639 int tmpwindow = !!(resv->r_flags & OCFS2_RESV_FLAG_TMP);
640 unsigned int min_bits;
641
642 if (!tmpwindow)
643 min_bits = ocfs2_resv_window_bits(resmap, resv) >> 1;
644 else
645 min_bits = wanted; /* We at know the temp window will use all
646 * of these bits */
647
648 /*
649 * Take the first reservation off the LRU as our 'target'. We
650 * don't try to be smart about it. There might be a case for
651 * searching based on size but I don't have enough data to be
652 * sure. --Mark (3/16/2010)
653 */
654 lru_resv = list_first_entry(&resmap->m_lru,
655 struct ocfs2_alloc_reservation, r_lru);
656
657 mlog(0, "lru resv: start: %u len: %u end: %u\n", lru_resv->r_start,
658 lru_resv->r_len, ocfs2_resv_end(lru_resv));
659
660 /*
661 * Cannibalize (some or all) of the target reservation and
662 * feed it to the current window.
663 */
664 if (lru_resv->r_len <= min_bits) {
665 /*
666 * Discard completely if size is less than or equal to a
667 * reasonable threshold - 50% of window bits for non temporary
668 * windows.
669 */
670 resv->r_start = lru_resv->r_start;
671 resv->r_len = lru_resv->r_len;
672
673 __ocfs2_resv_discard(resmap, lru_resv);
674 } else {
675 unsigned int shrink;
676 if (tmpwindow)
677 shrink = min_bits;
678 else
679 shrink = lru_resv->r_len / 2;
680
681 lru_resv->r_len -= shrink;
682
683 resv->r_start = ocfs2_resv_end(lru_resv) + 1;
684 resv->r_len = shrink;
685 }
686
687 mlog(0, "Reservation now looks like: r_start: %u r_end: %u "
688 "r_len: %u r_last_start: %u r_last_len: %u\n",
689 resv->r_start, ocfs2_resv_end(resv), resv->r_len,
690 resv->r_last_start, resv->r_last_len);
691
692 ocfs2_resv_insert(resmap, resv);
693}
694
695static void ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
696 struct ocfs2_alloc_reservation *resv,
697 unsigned int wanted)
698{
699 unsigned int goal = 0;
700
701 BUG_ON(!ocfs2_resv_empty(resv));
702
703 /*
704 * Begin by trying to get a window as close to the previous
705 * one as possible. Using the most recent allocation as a
706 * start goal makes sense.
707 */
708 if (resv->r_last_len) {
709 goal = resv->r_last_start + resv->r_last_len;
710 if (goal >= resmap->m_bitmap_len)
711 goal = 0;
712 }
713
714 __ocfs2_resv_find_window(resmap, resv, goal, wanted);
715
716 /* Search from last alloc didn't work, try once more from beginning. */
717 if (ocfs2_resv_empty(resv) && goal != 0)
718 __ocfs2_resv_find_window(resmap, resv, 0, wanted);
719
720 if (ocfs2_resv_empty(resv)) {
721 /*
722 * Still empty? Pull oldest one off the LRU, remove it from
723 * tree, put this one in it's place.
724 */
725 ocfs2_cannibalize_resv(resmap, resv, wanted);
726 }
727
728 BUG_ON(ocfs2_resv_empty(resv));
729}
730
731int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
732 struct ocfs2_alloc_reservation *resv,
733 int *cstart, int *clen)
734{
Mark Fashehd02f00c2009-12-07 13:10:48 -0800735 if (resv == NULL || ocfs2_resmap_disabled(resmap))
736 return -ENOSPC;
737
738 spin_lock(&resv_lock);
739
Mark Fashehd02f00c2009-12-07 13:10:48 -0800740 if (ocfs2_resv_empty(resv)) {
Tao Ma4a452de2010-09-19 13:42:28 +0800741 /*
742 * We don't want to over-allocate for temporary
743 * windows. Otherwise, we run the risk of fragmenting the
744 * allocation space.
745 */
746 unsigned int wanted = ocfs2_resv_window_bits(resmap, resv);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800747
Tao Ma4a452de2010-09-19 13:42:28 +0800748 if ((resv->r_flags & OCFS2_RESV_FLAG_TMP) || wanted < *clen)
749 wanted = *clen;
750
751 mlog(0, "empty reservation, find new window\n");
Mark Fashehd02f00c2009-12-07 13:10:48 -0800752 /*
753 * Try to get a window here. If it works, we must fall
754 * through and test the bitmap . This avoids some
755 * ping-ponging of windows due to non-reserved space
756 * being allocation before we initialize a window for
757 * that inode.
758 */
759 ocfs2_resv_find_window(resmap, resv, wanted);
760 }
761
762 BUG_ON(ocfs2_resv_empty(resv));
763
764 *cstart = resv->r_start;
765 *clen = resv->r_len;
766
767 spin_unlock(&resv_lock);
768 return 0;
769}
770
771static void
772 ocfs2_adjust_resv_from_alloc(struct ocfs2_reservation_map *resmap,
773 struct ocfs2_alloc_reservation *resv,
774 unsigned int start, unsigned int end)
775{
Tao Mab0655562010-04-08 16:33:02 +0800776 unsigned int rhs = 0;
777 unsigned int old_end = ocfs2_resv_end(resv);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800778
Tao Mab0655562010-04-08 16:33:02 +0800779 BUG_ON(start != resv->r_start || old_end < end);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800780
781 /*
782 * Completely used? We can remove it then.
783 */
Tao Mab0655562010-04-08 16:33:02 +0800784 if (old_end == end) {
Mark Fashehd02f00c2009-12-07 13:10:48 -0800785 __ocfs2_resv_discard(resmap, resv);
786 return;
787 }
788
Tao Mab0655562010-04-08 16:33:02 +0800789 rhs = old_end - end;
Mark Fashehd02f00c2009-12-07 13:10:48 -0800790
791 /*
Tao Mab0655562010-04-08 16:33:02 +0800792 * This should have been trapped above.
Mark Fashehd02f00c2009-12-07 13:10:48 -0800793 */
Tao Mab0655562010-04-08 16:33:02 +0800794 BUG_ON(rhs == 0);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800795
Tao Mab0655562010-04-08 16:33:02 +0800796 resv->r_start = end + 1;
797 resv->r_len = old_end - resv->r_start + 1;
Mark Fashehd02f00c2009-12-07 13:10:48 -0800798}
799
800void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
801 struct ocfs2_alloc_reservation *resv,
802 u32 cstart, u32 clen)
803{
804 unsigned int cend = cstart + clen - 1;
805
806 if (resmap == NULL || ocfs2_resmap_disabled(resmap))
807 return;
808
809 if (resv == NULL)
810 return;
811
Tao Mab0655562010-04-08 16:33:02 +0800812 BUG_ON(cstart != resv->r_start);
813
Mark Fashehd02f00c2009-12-07 13:10:48 -0800814 spin_lock(&resv_lock);
815
816 mlog(0, "claim bits: cstart: %u cend: %u clen: %u r_start: %u "
817 "r_end: %u r_len: %u, r_last_start: %u r_last_len: %u\n",
818 cstart, cend, clen, resv->r_start, ocfs2_resv_end(resv),
819 resv->r_len, resv->r_last_start, resv->r_last_len);
820
821 BUG_ON(cstart < resv->r_start);
822 BUG_ON(cstart > ocfs2_resv_end(resv));
823 BUG_ON(cend > ocfs2_resv_end(resv));
824
825 ocfs2_adjust_resv_from_alloc(resmap, resv, cstart, cend);
826 resv->r_last_start = cstart;
827 resv->r_last_len = clen;
828
829 /*
830 * May have been discarded above from
831 * ocfs2_adjust_resv_from_alloc().
832 */
833 if (!ocfs2_resv_empty(resv))
834 ocfs2_resv_mark_lru(resmap, resv);
835
836 mlog(0, "Reservation now looks like: r_start: %u r_end: %u "
837 "r_len: %u r_last_start: %u r_last_len: %u\n",
838 resv->r_start, ocfs2_resv_end(resv), resv->r_len,
839 resv->r_last_start, resv->r_last_len);
840
841 ocfs2_check_resmap(resmap);
842
843 spin_unlock(&resv_lock);
844}