blob: 41ffd36c689c23ff15bccb8d0b1a7e15526d999b [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
Mark Fashehd02f00c2009-12-07 13:10:48 -080033#include <cluster/masklog.h>
34
35#include "ocfs2.h"
Tao Ma26618362011-02-23 22:10:56 +080036#include "ocfs2_trace.h"
Mark Fashehd02f00c2009-12-07 13:10:48 -080037
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
Tao Ma26618362011-02-23 22:10:56 +0800324 trace_ocfs2_resv_insert(new->r_start, new->r_len);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800325
326 while (*p) {
327 parent = *p;
328
329 tmp = rb_entry(parent, struct ocfs2_alloc_reservation, r_node);
330
331 if (new->r_start < tmp->r_start) {
332 p = &(*p)->rb_left;
333
334 /*
335 * This is a good place to check for
336 * overlapping reservations.
337 */
338 BUG_ON(ocfs2_resv_end(new) >= tmp->r_start);
339 } else if (new->r_start > ocfs2_resv_end(tmp)) {
340 p = &(*p)->rb_right;
341 } else {
342 /* This should never happen! */
343 mlog(ML_ERROR, "Duplicate reservation window!\n");
344 BUG();
345 }
346 }
347
348 rb_link_node(&new->r_node, parent, p);
349 rb_insert_color(&new->r_node, root);
350 new->r_flags |= OCFS2_RESV_FLAG_INUSE;
351
352 ocfs2_resv_mark_lru(resmap, new);
353
354 ocfs2_check_resmap(resmap);
355}
356
357/**
358 * ocfs2_find_resv_lhs() - find the window which contains goal
359 * @resmap: reservation map to search
360 * @goal: which bit to search for
361 *
362 * If a window containing that goal is not found, we return the window
363 * which comes before goal. Returns NULL on empty rbtree or no window
364 * before goal.
365 */
366static struct ocfs2_alloc_reservation *
367ocfs2_find_resv_lhs(struct ocfs2_reservation_map *resmap, unsigned int goal)
368{
369 struct ocfs2_alloc_reservation *resv = NULL;
370 struct ocfs2_alloc_reservation *prev_resv = NULL;
371 struct rb_node *node = resmap->m_reservations.rb_node;
Mark Fashehd02f00c2009-12-07 13:10:48 -0800372
373 assert_spin_locked(&resv_lock);
374
375 if (!node)
376 return NULL;
377
378 node = rb_first(&resmap->m_reservations);
379 while (node) {
380 resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
381
382 if (resv->r_start <= goal && ocfs2_resv_end(resv) >= goal)
383 break;
384
385 /* Check if we overshot the reservation just before goal? */
386 if (resv->r_start > goal) {
387 resv = prev_resv;
388 break;
389 }
390
391 prev_resv = resv;
Mark Fashehd02f00c2009-12-07 13:10:48 -0800392 node = rb_next(node);
393 }
394
395 return resv;
396}
397
398/*
399 * We are given a range within the bitmap, which corresponds to a gap
400 * inside the reservations tree (search_start, search_len). The range
401 * can be anything from the whole bitmap, to a gap between
402 * reservations.
403 *
404 * The start value of *rstart is insignificant.
405 *
406 * This function searches the bitmap range starting at search_start
Tao Mab0655562010-04-08 16:33:02 +0800407 * with length search_len for a set of contiguous free bits. We try
Mark Fashehd02f00c2009-12-07 13:10:48 -0800408 * to find up to 'wanted' bits, but can sometimes return less.
409 *
410 * Returns the length of allocation, 0 if no free bits are found.
411 *
412 * *cstart and *clen will also be populated with the result.
413 */
414static int ocfs2_resmap_find_free_bits(struct ocfs2_reservation_map *resmap,
415 unsigned int wanted,
416 unsigned int search_start,
417 unsigned int search_len,
418 unsigned int *rstart,
419 unsigned int *rlen)
420{
421 void *bitmap = resmap->m_disk_bitmap;
422 unsigned int best_start, best_len = 0;
423 int offset, start, found;
424
Tao Ma26618362011-02-23 22:10:56 +0800425 trace_ocfs2_resmap_find_free_bits_begin(search_start, search_len,
426 wanted, resmap->m_bitmap_len);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800427
428 found = best_start = best_len = 0;
429
430 start = search_start;
431 while ((offset = ocfs2_find_next_zero_bit(bitmap, resmap->m_bitmap_len,
432 start)) != -1) {
433 /* Search reached end of the region */
434 if (offset >= (search_start + search_len))
435 break;
436
437 if (offset == start) {
438 /* we found a zero */
439 found++;
440 /* move start to the next bit to test */
441 start++;
442 } else {
443 /* got a zero after some ones */
444 found = 1;
445 start = offset + 1;
446 }
447 if (found > best_len) {
448 best_len = found;
449 best_start = start - found;
450 }
451
452 if (found >= wanted)
453 break;
454 }
455
456 if (best_len == 0)
457 return 0;
458
459 if (best_len >= wanted)
460 best_len = wanted;
461
462 *rlen = best_len;
463 *rstart = best_start;
464
Tao Ma26618362011-02-23 22:10:56 +0800465 trace_ocfs2_resmap_find_free_bits_end(best_start, best_len);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800466
467 return *rlen;
468}
469
470static void __ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
471 struct ocfs2_alloc_reservation *resv,
472 unsigned int goal, unsigned int wanted)
473{
474 struct rb_root *root = &resmap->m_reservations;
475 unsigned int gap_start, gap_end, gap_len;
476 struct ocfs2_alloc_reservation *prev_resv, *next_resv;
477 struct rb_node *prev, *next;
478 unsigned int cstart, clen;
479 unsigned int best_start = 0, best_len = 0;
480
481 /*
482 * Nasty cases to consider:
483 *
484 * - rbtree is empty
485 * - our window should be first in all reservations
486 * - our window should be last in all reservations
487 * - need to make sure we don't go past end of bitmap
488 */
Tao Ma26618362011-02-23 22:10:56 +0800489 trace_ocfs2_resv_find_window_begin(resv->r_start, ocfs2_resv_end(resv),
490 goal, wanted, RB_EMPTY_ROOT(root));
Mark Fashehd02f00c2009-12-07 13:10:48 -0800491
492 assert_spin_locked(&resv_lock);
493
494 if (RB_EMPTY_ROOT(root)) {
495 /*
496 * Easiest case - empty tree. We can just take
497 * whatever window of free bits we want.
498 */
Mark Fashehd02f00c2009-12-07 13:10:48 -0800499 clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
500 resmap->m_bitmap_len - goal,
501 &cstart, &clen);
502
503 /*
504 * This should never happen - the local alloc window
505 * will always have free bits when we're called.
506 */
507 BUG_ON(goal == 0 && clen == 0);
508
509 if (clen == 0)
510 return;
511
512 resv->r_start = cstart;
513 resv->r_len = clen;
514
515 ocfs2_resv_insert(resmap, resv);
516 return;
517 }
518
519 prev_resv = ocfs2_find_resv_lhs(resmap, goal);
520
521 if (prev_resv == NULL) {
Mark Fashehd02f00c2009-12-07 13:10:48 -0800522 /*
523 * A NULL here means that the search code couldn't
524 * find a window that starts before goal.
525 *
526 * However, we can take the first window after goal,
527 * which is also by definition, the leftmost window in
528 * the entire tree. If we can find free bits in the
529 * gap between goal and the LHS window, then the
530 * reservation can safely be placed there.
531 *
532 * Otherwise we fall back to a linear search, checking
533 * the gaps in between windows for a place to
534 * allocate.
535 */
536
537 next = rb_first(root);
538 next_resv = rb_entry(next, struct ocfs2_alloc_reservation,
539 r_node);
540
541 /*
542 * The search should never return such a window. (see
543 * comment above
544 */
545 if (next_resv->r_start <= goal) {
546 mlog(ML_ERROR, "goal: %u next_resv: start %u len %u\n",
547 goal, next_resv->r_start, next_resv->r_len);
548 ocfs2_dump_resv(resmap);
549 BUG();
550 }
551
552 clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
553 next_resv->r_start - goal,
554 &cstart, &clen);
555 if (clen) {
556 best_len = clen;
557 best_start = cstart;
558 if (best_len == wanted)
559 goto out_insert;
560 }
561
562 prev_resv = next_resv;
563 next_resv = NULL;
564 }
565
Tao Ma26618362011-02-23 22:10:56 +0800566 trace_ocfs2_resv_find_window_prev(prev_resv->r_start,
567 ocfs2_resv_end(prev_resv));
568
Mark Fashehd02f00c2009-12-07 13:10:48 -0800569 prev = &prev_resv->r_node;
570
571 /* Now we do a linear search for a window, starting at 'prev_rsv' */
572 while (1) {
573 next = rb_next(prev);
574 if (next) {
Mark Fashehd02f00c2009-12-07 13:10:48 -0800575 next_resv = rb_entry(next,
576 struct ocfs2_alloc_reservation,
577 r_node);
578
579 gap_start = ocfs2_resv_end(prev_resv) + 1;
580 gap_end = next_resv->r_start - 1;
581 gap_len = gap_end - gap_start + 1;
582 } else {
Mark Fashehd02f00c2009-12-07 13:10:48 -0800583 /*
584 * We're at the rightmost edge of the
585 * tree. See if a reservation between this
586 * window and the end of the bitmap will work.
587 */
588 gap_start = ocfs2_resv_end(prev_resv) + 1;
589 gap_len = resmap->m_bitmap_len - gap_start;
590 gap_end = resmap->m_bitmap_len - 1;
591 }
592
Tao Ma26618362011-02-23 22:10:56 +0800593 trace_ocfs2_resv_find_window_next(next ? next_resv->r_start: -1,
594 next ? ocfs2_resv_end(next_resv) : -1);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800595 /*
596 * No need to check this gap if we have already found
597 * a larger region of free bits.
598 */
599 if (gap_len <= best_len)
600 goto next_resv;
601
602 clen = ocfs2_resmap_find_free_bits(resmap, wanted, gap_start,
603 gap_len, &cstart, &clen);
604 if (clen == wanted) {
605 best_len = clen;
606 best_start = cstart;
607 goto out_insert;
608 } else if (clen > best_len) {
609 best_len = clen;
610 best_start = cstart;
611 }
612
613next_resv:
614 if (!next)
615 break;
616
617 prev = next;
618 prev_resv = rb_entry(prev, struct ocfs2_alloc_reservation,
619 r_node);
620 }
621
622out_insert:
623 if (best_len) {
624 resv->r_start = best_start;
625 resv->r_len = best_len;
626 ocfs2_resv_insert(resmap, resv);
627 }
628}
629
630static void ocfs2_cannibalize_resv(struct ocfs2_reservation_map *resmap,
631 struct ocfs2_alloc_reservation *resv,
632 unsigned int wanted)
633{
634 struct ocfs2_alloc_reservation *lru_resv;
635 int tmpwindow = !!(resv->r_flags & OCFS2_RESV_FLAG_TMP);
636 unsigned int min_bits;
637
638 if (!tmpwindow)
639 min_bits = ocfs2_resv_window_bits(resmap, resv) >> 1;
640 else
641 min_bits = wanted; /* We at know the temp window will use all
642 * of these bits */
643
644 /*
645 * Take the first reservation off the LRU as our 'target'. We
646 * don't try to be smart about it. There might be a case for
647 * searching based on size but I don't have enough data to be
648 * sure. --Mark (3/16/2010)
649 */
650 lru_resv = list_first_entry(&resmap->m_lru,
651 struct ocfs2_alloc_reservation, r_lru);
652
Tao Ma26618362011-02-23 22:10:56 +0800653 trace_ocfs2_cannibalize_resv_begin(lru_resv->r_start,
654 lru_resv->r_len,
655 ocfs2_resv_end(lru_resv));
Mark Fashehd02f00c2009-12-07 13:10:48 -0800656
657 /*
658 * Cannibalize (some or all) of the target reservation and
659 * feed it to the current window.
660 */
661 if (lru_resv->r_len <= min_bits) {
662 /*
663 * Discard completely if size is less than or equal to a
664 * reasonable threshold - 50% of window bits for non temporary
665 * windows.
666 */
667 resv->r_start = lru_resv->r_start;
668 resv->r_len = lru_resv->r_len;
669
670 __ocfs2_resv_discard(resmap, lru_resv);
671 } else {
672 unsigned int shrink;
673 if (tmpwindow)
674 shrink = min_bits;
675 else
676 shrink = lru_resv->r_len / 2;
677
678 lru_resv->r_len -= shrink;
679
680 resv->r_start = ocfs2_resv_end(lru_resv) + 1;
681 resv->r_len = shrink;
682 }
683
Tao Ma26618362011-02-23 22:10:56 +0800684 trace_ocfs2_cannibalize_resv_end(resv->r_start, ocfs2_resv_end(resv),
685 resv->r_len, resv->r_last_start,
686 resv->r_last_len);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800687
688 ocfs2_resv_insert(resmap, resv);
689}
690
691static void ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
692 struct ocfs2_alloc_reservation *resv,
693 unsigned int wanted)
694{
695 unsigned int goal = 0;
696
697 BUG_ON(!ocfs2_resv_empty(resv));
698
699 /*
700 * Begin by trying to get a window as close to the previous
701 * one as possible. Using the most recent allocation as a
702 * start goal makes sense.
703 */
704 if (resv->r_last_len) {
705 goal = resv->r_last_start + resv->r_last_len;
706 if (goal >= resmap->m_bitmap_len)
707 goal = 0;
708 }
709
710 __ocfs2_resv_find_window(resmap, resv, goal, wanted);
711
712 /* Search from last alloc didn't work, try once more from beginning. */
713 if (ocfs2_resv_empty(resv) && goal != 0)
714 __ocfs2_resv_find_window(resmap, resv, 0, wanted);
715
716 if (ocfs2_resv_empty(resv)) {
717 /*
718 * Still empty? Pull oldest one off the LRU, remove it from
719 * tree, put this one in it's place.
720 */
721 ocfs2_cannibalize_resv(resmap, resv, wanted);
722 }
723
724 BUG_ON(ocfs2_resv_empty(resv));
725}
726
727int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
728 struct ocfs2_alloc_reservation *resv,
729 int *cstart, int *clen)
730{
Mark Fashehd02f00c2009-12-07 13:10:48 -0800731 if (resv == NULL || ocfs2_resmap_disabled(resmap))
732 return -ENOSPC;
733
734 spin_lock(&resv_lock);
735
Mark Fashehd02f00c2009-12-07 13:10:48 -0800736 if (ocfs2_resv_empty(resv)) {
Tao Ma4a452de2010-09-19 13:42:28 +0800737 /*
738 * We don't want to over-allocate for temporary
739 * windows. Otherwise, we run the risk of fragmenting the
740 * allocation space.
741 */
742 unsigned int wanted = ocfs2_resv_window_bits(resmap, resv);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800743
Tao Ma4a452de2010-09-19 13:42:28 +0800744 if ((resv->r_flags & OCFS2_RESV_FLAG_TMP) || wanted < *clen)
745 wanted = *clen;
746
Mark Fashehd02f00c2009-12-07 13:10:48 -0800747 /*
748 * Try to get a window here. If it works, we must fall
749 * through and test the bitmap . This avoids some
750 * ping-ponging of windows due to non-reserved space
751 * being allocation before we initialize a window for
752 * that inode.
753 */
754 ocfs2_resv_find_window(resmap, resv, wanted);
Tao Ma26618362011-02-23 22:10:56 +0800755 trace_ocfs2_resmap_resv_bits(resv->r_start, resv->r_len);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800756 }
757
758 BUG_ON(ocfs2_resv_empty(resv));
759
760 *cstart = resv->r_start;
761 *clen = resv->r_len;
762
763 spin_unlock(&resv_lock);
764 return 0;
765}
766
767static void
768 ocfs2_adjust_resv_from_alloc(struct ocfs2_reservation_map *resmap,
769 struct ocfs2_alloc_reservation *resv,
770 unsigned int start, unsigned int end)
771{
Tao Mab0655562010-04-08 16:33:02 +0800772 unsigned int rhs = 0;
773 unsigned int old_end = ocfs2_resv_end(resv);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800774
Tao Mab0655562010-04-08 16:33:02 +0800775 BUG_ON(start != resv->r_start || old_end < end);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800776
777 /*
778 * Completely used? We can remove it then.
779 */
Tao Mab0655562010-04-08 16:33:02 +0800780 if (old_end == end) {
Mark Fashehd02f00c2009-12-07 13:10:48 -0800781 __ocfs2_resv_discard(resmap, resv);
782 return;
783 }
784
Tao Mab0655562010-04-08 16:33:02 +0800785 rhs = old_end - end;
Mark Fashehd02f00c2009-12-07 13:10:48 -0800786
787 /*
Tao Mab0655562010-04-08 16:33:02 +0800788 * This should have been trapped above.
Mark Fashehd02f00c2009-12-07 13:10:48 -0800789 */
Tao Mab0655562010-04-08 16:33:02 +0800790 BUG_ON(rhs == 0);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800791
Tao Mab0655562010-04-08 16:33:02 +0800792 resv->r_start = end + 1;
793 resv->r_len = old_end - resv->r_start + 1;
Mark Fashehd02f00c2009-12-07 13:10:48 -0800794}
795
796void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
797 struct ocfs2_alloc_reservation *resv,
798 u32 cstart, u32 clen)
799{
800 unsigned int cend = cstart + clen - 1;
801
802 if (resmap == NULL || ocfs2_resmap_disabled(resmap))
803 return;
804
805 if (resv == NULL)
806 return;
807
Tao Mab0655562010-04-08 16:33:02 +0800808 BUG_ON(cstart != resv->r_start);
809
Mark Fashehd02f00c2009-12-07 13:10:48 -0800810 spin_lock(&resv_lock);
811
Tao Ma26618362011-02-23 22:10:56 +0800812 trace_ocfs2_resmap_claimed_bits_begin(cstart, cend, clen, resv->r_start,
813 ocfs2_resv_end(resv), resv->r_len,
814 resv->r_last_start,
815 resv->r_last_len);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800816
817 BUG_ON(cstart < resv->r_start);
818 BUG_ON(cstart > ocfs2_resv_end(resv));
819 BUG_ON(cend > ocfs2_resv_end(resv));
820
821 ocfs2_adjust_resv_from_alloc(resmap, resv, cstart, cend);
822 resv->r_last_start = cstart;
823 resv->r_last_len = clen;
824
825 /*
826 * May have been discarded above from
827 * ocfs2_adjust_resv_from_alloc().
828 */
829 if (!ocfs2_resv_empty(resv))
830 ocfs2_resv_mark_lru(resmap, resv);
831
Tao Ma26618362011-02-23 22:10:56 +0800832 trace_ocfs2_resmap_claimed_bits_end(resv->r_start, ocfs2_resv_end(resv),
833 resv->r_len, resv->r_last_start,
834 resv->r_last_len);
Mark Fashehd02f00c2009-12-07 13:10:48 -0800835
836 ocfs2_check_resmap(resmap);
837
838 spin_unlock(&resv_lock);
839}