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 | |
32 | static DEFINE_SPINLOCK(resv_lock); |
33 | |
34 | int ocfs2_dir_resv_allowed(struct ocfs2_super *osb) |
35 | { |
36 | return (osb->osb_resv_level && osb->osb_dir_resv_level); |
37 | } |
38 | |
39 | static 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 | |
54 | static 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 | |
61 | static inline int ocfs2_resv_empty(struct ocfs2_alloc_reservation *resv) |
62 | { |
63 | return !!(resv->r_len == 0); |
64 | } |
65 | |
66 | static 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 | |
73 | static 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 |
110 | static 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(nr: start, addr: 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 | |
131 | static 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 | |
176 | bad: |
177 | ocfs2_dump_resv(resmap); |
178 | BUG(); |
179 | } |
180 | #else |
181 | static inline void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap) |
182 | { |
183 | |
184 | } |
185 | #endif |
186 | |
187 | void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv) |
188 | { |
189 | memset(resv, 0, sizeof(*resv)); |
190 | INIT_LIST_HEAD(list: &resv->r_lru); |
191 | } |
192 | |
193 | void 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 | |
201 | void 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(list: &resmap->m_lru); |
210 | } |
211 | |
212 | static 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(head: &resv->r_lru)) |
218 | list_del_init(entry: &resv->r_lru); |
219 | |
220 | list_add_tail(new: &resv->r_lru, head: &resmap->m_lru); |
221 | } |
222 | |
223 | static void __ocfs2_resv_trunc(struct ocfs2_alloc_reservation *resv) |
224 | { |
225 | resv->r_len = 0; |
226 | resv->r_start = 0; |
227 | } |
228 | |
229 | static 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(entry: &resv->r_lru); |
234 | rb_erase(&resv->r_node, &resmap->m_reservations); |
235 | resv->r_flags &= ~OCFS2_RESV_FLAG_INUSE; |
236 | } |
237 | } |
238 | |
239 | static 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 */ |
255 | void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap, |
256 | struct ocfs2_alloc_reservation *resv) |
257 | { |
258 | if (resv) { |
259 | spin_lock(lock: &resv_lock); |
260 | __ocfs2_resv_discard(resmap, resv); |
261 | spin_unlock(lock: &resv_lock); |
262 | } |
263 | } |
264 | |
265 | static 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 | |
279 | void 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(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(lock: &resv_lock); |
292 | } |
293 | |
294 | void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap) |
295 | { |
296 | /* Does nothing for now. Keep this around for API symmetry */ |
297 | } |
298 | |
299 | static 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(val1: new->r_start, val2: 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(resv: 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(node: &new->r_node, parent, rb_link: p); |
334 | rb_insert_color(&new->r_node, root); |
335 | new->r_flags |= OCFS2_RESV_FLAG_INUSE; |
336 | |
337 | ocfs2_resv_mark_lru(resmap, resv: 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 | */ |
351 | static struct ocfs2_alloc_reservation * |
352 | ocfs2_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 | */ |
399 | static 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(ull: search_start, value1: search_len, |
411 | value2: wanted, value3: 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(addr: bitmap, size: resmap->m_bitmap_len, |
417 | offset: 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(val1: best_start, val2: best_len); |
451 | |
452 | return *rlen; |
453 | } |
454 | |
455 | static 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(r_start: resv->r_start, r_end: 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, search_start: goal, |
485 | search_len: resmap->m_bitmap_len - goal, |
486 | rstart: &cstart, rlen: &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, new: 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, search_start: goal, |
538 | search_len: next_resv->r_start - goal, |
539 | rstart: &cstart, rlen: &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(val1: prev_resv->r_start, |
552 | val2: ocfs2_resv_end(resv: 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(resv: 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(resv: 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(val1: next ? next_resv->r_start: -1, |
579 | val2: next ? ocfs2_resv_end(resv: 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, search_start: gap_start, |
588 | search_len: gap_len, rstart: &cstart, rlen: &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 | |
598 | next_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 | |
607 | out_insert: |
608 | if (best_len) { |
609 | resv->r_start = best_start; |
610 | resv->r_len = best_len; |
611 | ocfs2_resv_insert(resmap, new: resv); |
612 | } |
613 | } |
614 | |
615 | static 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(value1: lru_resv->r_start, |
639 | value2: lru_resv->r_len, |
640 | value3: ocfs2_resv_end(resv: 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, resv: 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(resv: lru_resv) + 1; |
666 | resv->r_len = shrink; |
667 | } |
668 | |
669 | trace_ocfs2_cannibalize_resv_end(start: resv->r_start, end: ocfs2_resv_end(resv), |
670 | len: resv->r_len, last_start: resv->r_last_start, |
671 | last_len: resv->r_last_len); |
672 | |
673 | ocfs2_resv_insert(resmap, new: resv); |
674 | } |
675 | |
676 | static 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, goal: 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 | |
712 | int 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(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(val1: resv->r_start, val2: 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(lock: &resv_lock); |
749 | return 0; |
750 | } |
751 | |
752 | static 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 | |
781 | void 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(lock: &resv_lock); |
796 | |
797 | trace_ocfs2_resmap_claimed_bits_begin(cstart, cend, clen, r_start: resv->r_start, |
798 | r_end: ocfs2_resv_end(resv), r_len: resv->r_len, |
799 | last_start: resv->r_last_start, |
800 | last_len: 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, start: cstart, end: 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(start: resv->r_start, end: ocfs2_resv_end(resv), |
818 | len: resv->r_len, last_start: resv->r_last_start, |
819 | last_len: resv->r_last_len); |
820 | |
821 | ocfs2_check_resmap(resmap); |
822 | |
823 | spin_unlock(lock: &resv_lock); |
824 | } |
825 | |