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d02f00cc MF |
1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
3 | * | |
4 | * reservations.c | |
5 | * | |
6 | * Allocation reservations implementation | |
7 | * | |
8 | * Some code borrowed from fs/ext3/balloc.c and is: | |
9 | * | |
10 | * Copyright (C) 1992, 1993, 1994, 1995 | |
11 | * Remy Card (card@masi.ibp.fr) | |
12 | * Laboratoire MASI - Institut Blaise Pascal | |
13 | * Universite Pierre et Marie Curie (Paris VI) | |
14 | * | |
15 | * The rest is copyright (C) 2010 Novell. All rights reserved. | |
16 | * | |
17 | * This program is free software; you can redistribute it and/or | |
18 | * modify it under the terms of the GNU General Public | |
19 | * License version 2 as published by the Free Software Foundation. | |
20 | * | |
21 | * This program is distributed in the hope that it will be useful, | |
22 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
23 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
24 | * General Public License for more details. | |
25 | */ | |
26 | ||
27 | #include <linux/fs.h> | |
28 | #include <linux/types.h> | |
d02f00cc MF |
29 | #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 | ||
42 | DEFINE_SPINLOCK(resv_lock); | |
43 | ||
44 | #define OCFS2_MIN_RESV_WINDOW_BITS 8 | |
45 | #define OCFS2_MAX_RESV_WINDOW_BITS 1024 | |
83f92318 MF |
46 | |
47 | int ocfs2_dir_resv_allowed(struct ocfs2_super *osb) | |
48 | { | |
49 | return (osb->osb_resv_level && osb->osb_dir_resv_level); | |
50 | } | |
d02f00cc MF |
51 | |
52 | static 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 | ||
e3b4a97d MF |
58 | if (!(resv->r_flags & OCFS2_RESV_FLAG_DIR)) { |
59 | /* 8, 16, 32, 64, 128, 256, 512, 1024 */ | |
60 | bits = 4 << osb->osb_resv_level; | |
b07f8f24 | 61 | } else { |
83f92318 | 62 | bits = 4 << osb->osb_dir_resv_level; |
b07f8f24 | 63 | } |
d02f00cc MF |
64 | return bits; |
65 | } | |
66 | ||
67 | static 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 | ||
74 | static inline int ocfs2_resv_empty(struct ocfs2_alloc_reservation *resv) | |
75 | { | |
76 | return !!(resv->r_len == 0); | |
77 | } | |
78 | ||
79 | static 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 | ||
86 | static 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 | |
123 | static 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 | ||
144 | static 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 | ||
189 | bad: | |
190 | ocfs2_dump_resv(resmap); | |
191 | BUG(); | |
192 | } | |
193 | #else | |
194 | static inline void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap) | |
195 | { | |
196 | ||
197 | } | |
198 | #endif | |
199 | ||
200 | void 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 | ||
206 | void 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 | ||
214 | int 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 | ||
227 | static 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 | ||
238 | static void __ocfs2_resv_trunc(struct ocfs2_alloc_reservation *resv) | |
239 | { | |
240 | resv->r_len = 0; | |
241 | resv->r_start = 0; | |
242 | } | |
243 | ||
244 | static 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 | ||
254 | static 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 */ | |
270 | void 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 | ||
280 | static 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 | ||
294 | void 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 | ||
309 | void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap) | |
310 | { | |
311 | /* Does nothing for now. Keep this around for API symmetry */ | |
312 | } | |
313 | ||
314 | static 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 | */ | |
367 | static struct ocfs2_alloc_reservation * | |
368 | ocfs2_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; | |
d02f00cc MF |
373 | |
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; | |
d02f00cc MF |
393 | 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 | |
b065556a | 408 | * with length search_len for a set of contiguous free bits. We try |
d02f00cc MF |
409 | * 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 | */ | |
415 | static 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 | ||
471 | static 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 | ||
617 | next_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 | ||
626 | out_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 | ||
634 | static 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 | ||
695 | static 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 | ||
731 | int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap, | |
732 | struct ocfs2_alloc_reservation *resv, | |
733 | int *cstart, int *clen) | |
734 | { | |
d02f00cc MF |
735 | if (resv == NULL || ocfs2_resmap_disabled(resmap)) |
736 | return -ENOSPC; | |
737 | ||
738 | spin_lock(&resv_lock); | |
739 | ||
d02f00cc | 740 | if (ocfs2_resv_empty(resv)) { |
4a452de4 TM |
741 | /* |
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); | |
d02f00cc | 747 | |
4a452de4 TM |
748 | if ((resv->r_flags & OCFS2_RESV_FLAG_TMP) || wanted < *clen) |
749 | wanted = *clen; | |
750 | ||
751 | mlog(0, "empty reservation, find new window\n"); | |
d02f00cc MF |
752 | /* |
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 | ||
771 | static 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 | { | |
b065556a TM |
776 | unsigned int rhs = 0; |
777 | unsigned int old_end = ocfs2_resv_end(resv); | |
d02f00cc | 778 | |
b065556a | 779 | BUG_ON(start != resv->r_start || old_end < end); |
d02f00cc MF |
780 | |
781 | /* | |
782 | * Completely used? We can remove it then. | |
783 | */ | |
b065556a | 784 | if (old_end == end) { |
d02f00cc MF |
785 | __ocfs2_resv_discard(resmap, resv); |
786 | return; | |
787 | } | |
788 | ||
b065556a | 789 | rhs = old_end - end; |
d02f00cc MF |
790 | |
791 | /* | |
b065556a | 792 | * This should have been trapped above. |
d02f00cc | 793 | */ |
b065556a | 794 | BUG_ON(rhs == 0); |
d02f00cc | 795 | |
b065556a TM |
796 | resv->r_start = end + 1; |
797 | resv->r_len = old_end - resv->r_start + 1; | |
d02f00cc MF |
798 | } |
799 | ||
800 | void 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 | ||
b065556a TM |
812 | BUG_ON(cstart != resv->r_start); |
813 | ||
d02f00cc MF |
814 | 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 | } |