xref: /linux/fs/xfs/libxfs/xfs_alloc_btree.c (revision 1e0731c05c985deb68a97fa44c1adcd3305dda90)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
4  * All Rights Reserved.
5  */
6 #include "xfs.h"
7 #include "xfs_fs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_mount.h"
13 #include "xfs_btree.h"
14 #include "xfs_btree_staging.h"
15 #include "xfs_alloc_btree.h"
16 #include "xfs_alloc.h"
17 #include "xfs_extent_busy.h"
18 #include "xfs_error.h"
19 #include "xfs_trace.h"
20 #include "xfs_trans.h"
21 #include "xfs_ag.h"
22 
23 static struct kmem_cache	*xfs_allocbt_cur_cache;
24 
25 STATIC struct xfs_btree_cur *
26 xfs_allocbt_dup_cursor(
27 	struct xfs_btree_cur	*cur)
28 {
29 	return xfs_allocbt_init_cursor(cur->bc_mp, cur->bc_tp,
30 			cur->bc_ag.agbp, cur->bc_ag.pag, cur->bc_btnum);
31 }
32 
33 STATIC void
34 xfs_allocbt_set_root(
35 	struct xfs_btree_cur		*cur,
36 	const union xfs_btree_ptr	*ptr,
37 	int				inc)
38 {
39 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
40 	struct xfs_agf		*agf = agbp->b_addr;
41 	int			btnum = cur->bc_btnum;
42 
43 	ASSERT(ptr->s != 0);
44 
45 	agf->agf_roots[btnum] = ptr->s;
46 	be32_add_cpu(&agf->agf_levels[btnum], inc);
47 	cur->bc_ag.pag->pagf_levels[btnum] += inc;
48 
49 	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
50 }
51 
52 STATIC int
53 xfs_allocbt_alloc_block(
54 	struct xfs_btree_cur		*cur,
55 	const union xfs_btree_ptr	*start,
56 	union xfs_btree_ptr		*new,
57 	int				*stat)
58 {
59 	int			error;
60 	xfs_agblock_t		bno;
61 
62 	/* Allocate the new block from the freelist. If we can't, give up.  */
63 	error = xfs_alloc_get_freelist(cur->bc_ag.pag, cur->bc_tp,
64 			cur->bc_ag.agbp, &bno, 1);
65 	if (error)
66 		return error;
67 
68 	if (bno == NULLAGBLOCK) {
69 		*stat = 0;
70 		return 0;
71 	}
72 
73 	atomic64_inc(&cur->bc_mp->m_allocbt_blks);
74 	xfs_extent_busy_reuse(cur->bc_mp, cur->bc_ag.pag, bno, 1, false);
75 
76 	new->s = cpu_to_be32(bno);
77 
78 	*stat = 1;
79 	return 0;
80 }
81 
82 STATIC int
83 xfs_allocbt_free_block(
84 	struct xfs_btree_cur	*cur,
85 	struct xfs_buf		*bp)
86 {
87 	struct xfs_buf		*agbp = cur->bc_ag.agbp;
88 	xfs_agblock_t		bno;
89 	int			error;
90 
91 	bno = xfs_daddr_to_agbno(cur->bc_mp, xfs_buf_daddr(bp));
92 	error = xfs_alloc_put_freelist(cur->bc_ag.pag, cur->bc_tp, agbp, NULL,
93 			bno, 1);
94 	if (error)
95 		return error;
96 
97 	atomic64_dec(&cur->bc_mp->m_allocbt_blks);
98 	xfs_extent_busy_insert(cur->bc_tp, agbp->b_pag, bno, 1,
99 			      XFS_EXTENT_BUSY_SKIP_DISCARD);
100 	return 0;
101 }
102 
103 /*
104  * Update the longest extent in the AGF
105  */
106 STATIC void
107 xfs_allocbt_update_lastrec(
108 	struct xfs_btree_cur		*cur,
109 	const struct xfs_btree_block	*block,
110 	const union xfs_btree_rec	*rec,
111 	int				ptr,
112 	int				reason)
113 {
114 	struct xfs_agf		*agf = cur->bc_ag.agbp->b_addr;
115 	struct xfs_perag	*pag;
116 	__be32			len;
117 	int			numrecs;
118 
119 	ASSERT(cur->bc_btnum == XFS_BTNUM_CNT);
120 
121 	switch (reason) {
122 	case LASTREC_UPDATE:
123 		/*
124 		 * If this is the last leaf block and it's the last record,
125 		 * then update the size of the longest extent in the AG.
126 		 */
127 		if (ptr != xfs_btree_get_numrecs(block))
128 			return;
129 		len = rec->alloc.ar_blockcount;
130 		break;
131 	case LASTREC_INSREC:
132 		if (be32_to_cpu(rec->alloc.ar_blockcount) <=
133 		    be32_to_cpu(agf->agf_longest))
134 			return;
135 		len = rec->alloc.ar_blockcount;
136 		break;
137 	case LASTREC_DELREC:
138 		numrecs = xfs_btree_get_numrecs(block);
139 		if (ptr <= numrecs)
140 			return;
141 		ASSERT(ptr == numrecs + 1);
142 
143 		if (numrecs) {
144 			xfs_alloc_rec_t *rrp;
145 
146 			rrp = XFS_ALLOC_REC_ADDR(cur->bc_mp, block, numrecs);
147 			len = rrp->ar_blockcount;
148 		} else {
149 			len = 0;
150 		}
151 
152 		break;
153 	default:
154 		ASSERT(0);
155 		return;
156 	}
157 
158 	agf->agf_longest = len;
159 	pag = cur->bc_ag.agbp->b_pag;
160 	pag->pagf_longest = be32_to_cpu(len);
161 	xfs_alloc_log_agf(cur->bc_tp, cur->bc_ag.agbp, XFS_AGF_LONGEST);
162 }
163 
164 STATIC int
165 xfs_allocbt_get_minrecs(
166 	struct xfs_btree_cur	*cur,
167 	int			level)
168 {
169 	return cur->bc_mp->m_alloc_mnr[level != 0];
170 }
171 
172 STATIC int
173 xfs_allocbt_get_maxrecs(
174 	struct xfs_btree_cur	*cur,
175 	int			level)
176 {
177 	return cur->bc_mp->m_alloc_mxr[level != 0];
178 }
179 
180 STATIC void
181 xfs_allocbt_init_key_from_rec(
182 	union xfs_btree_key		*key,
183 	const union xfs_btree_rec	*rec)
184 {
185 	key->alloc.ar_startblock = rec->alloc.ar_startblock;
186 	key->alloc.ar_blockcount = rec->alloc.ar_blockcount;
187 }
188 
189 STATIC void
190 xfs_bnobt_init_high_key_from_rec(
191 	union xfs_btree_key		*key,
192 	const union xfs_btree_rec	*rec)
193 {
194 	__u32				x;
195 
196 	x = be32_to_cpu(rec->alloc.ar_startblock);
197 	x += be32_to_cpu(rec->alloc.ar_blockcount) - 1;
198 	key->alloc.ar_startblock = cpu_to_be32(x);
199 	key->alloc.ar_blockcount = 0;
200 }
201 
202 STATIC void
203 xfs_cntbt_init_high_key_from_rec(
204 	union xfs_btree_key		*key,
205 	const union xfs_btree_rec	*rec)
206 {
207 	key->alloc.ar_blockcount = rec->alloc.ar_blockcount;
208 	key->alloc.ar_startblock = 0;
209 }
210 
211 STATIC void
212 xfs_allocbt_init_rec_from_cur(
213 	struct xfs_btree_cur	*cur,
214 	union xfs_btree_rec	*rec)
215 {
216 	rec->alloc.ar_startblock = cpu_to_be32(cur->bc_rec.a.ar_startblock);
217 	rec->alloc.ar_blockcount = cpu_to_be32(cur->bc_rec.a.ar_blockcount);
218 }
219 
220 STATIC void
221 xfs_allocbt_init_ptr_from_cur(
222 	struct xfs_btree_cur	*cur,
223 	union xfs_btree_ptr	*ptr)
224 {
225 	struct xfs_agf		*agf = cur->bc_ag.agbp->b_addr;
226 
227 	ASSERT(cur->bc_ag.pag->pag_agno == be32_to_cpu(agf->agf_seqno));
228 
229 	ptr->s = agf->agf_roots[cur->bc_btnum];
230 }
231 
232 STATIC int64_t
233 xfs_bnobt_key_diff(
234 	struct xfs_btree_cur		*cur,
235 	const union xfs_btree_key	*key)
236 {
237 	struct xfs_alloc_rec_incore	*rec = &cur->bc_rec.a;
238 	const struct xfs_alloc_rec	*kp = &key->alloc;
239 
240 	return (int64_t)be32_to_cpu(kp->ar_startblock) - rec->ar_startblock;
241 }
242 
243 STATIC int64_t
244 xfs_cntbt_key_diff(
245 	struct xfs_btree_cur		*cur,
246 	const union xfs_btree_key	*key)
247 {
248 	struct xfs_alloc_rec_incore	*rec = &cur->bc_rec.a;
249 	const struct xfs_alloc_rec	*kp = &key->alloc;
250 	int64_t				diff;
251 
252 	diff = (int64_t)be32_to_cpu(kp->ar_blockcount) - rec->ar_blockcount;
253 	if (diff)
254 		return diff;
255 
256 	return (int64_t)be32_to_cpu(kp->ar_startblock) - rec->ar_startblock;
257 }
258 
259 STATIC int64_t
260 xfs_bnobt_diff_two_keys(
261 	struct xfs_btree_cur		*cur,
262 	const union xfs_btree_key	*k1,
263 	const union xfs_btree_key	*k2,
264 	const union xfs_btree_key	*mask)
265 {
266 	ASSERT(!mask || mask->alloc.ar_startblock);
267 
268 	return (int64_t)be32_to_cpu(k1->alloc.ar_startblock) -
269 			be32_to_cpu(k2->alloc.ar_startblock);
270 }
271 
272 STATIC int64_t
273 xfs_cntbt_diff_two_keys(
274 	struct xfs_btree_cur		*cur,
275 	const union xfs_btree_key	*k1,
276 	const union xfs_btree_key	*k2,
277 	const union xfs_btree_key	*mask)
278 {
279 	int64_t				diff;
280 
281 	ASSERT(!mask || (mask->alloc.ar_blockcount &&
282 			 mask->alloc.ar_startblock));
283 
284 	diff =  be32_to_cpu(k1->alloc.ar_blockcount) -
285 		be32_to_cpu(k2->alloc.ar_blockcount);
286 	if (diff)
287 		return diff;
288 
289 	return  be32_to_cpu(k1->alloc.ar_startblock) -
290 		be32_to_cpu(k2->alloc.ar_startblock);
291 }
292 
293 static xfs_failaddr_t
294 xfs_allocbt_verify(
295 	struct xfs_buf		*bp)
296 {
297 	struct xfs_mount	*mp = bp->b_mount;
298 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
299 	struct xfs_perag	*pag = bp->b_pag;
300 	xfs_failaddr_t		fa;
301 	unsigned int		level;
302 	xfs_btnum_t		btnum = XFS_BTNUM_BNOi;
303 
304 	if (!xfs_verify_magic(bp, block->bb_magic))
305 		return __this_address;
306 
307 	if (xfs_has_crc(mp)) {
308 		fa = xfs_btree_sblock_v5hdr_verify(bp);
309 		if (fa)
310 			return fa;
311 	}
312 
313 	/*
314 	 * The perag may not be attached during grow operations or fully
315 	 * initialized from the AGF during log recovery. Therefore we can only
316 	 * check against maximum tree depth from those contexts.
317 	 *
318 	 * Otherwise check against the per-tree limit. Peek at one of the
319 	 * verifier magic values to determine the type of tree we're verifying
320 	 * against.
321 	 */
322 	level = be16_to_cpu(block->bb_level);
323 	if (bp->b_ops->magic[0] == cpu_to_be32(XFS_ABTC_MAGIC))
324 		btnum = XFS_BTNUM_CNTi;
325 	if (pag && xfs_perag_initialised_agf(pag)) {
326 		if (level >= pag->pagf_levels[btnum])
327 			return __this_address;
328 	} else if (level >= mp->m_alloc_maxlevels)
329 		return __this_address;
330 
331 	return xfs_btree_sblock_verify(bp, mp->m_alloc_mxr[level != 0]);
332 }
333 
334 static void
335 xfs_allocbt_read_verify(
336 	struct xfs_buf	*bp)
337 {
338 	xfs_failaddr_t	fa;
339 
340 	if (!xfs_btree_sblock_verify_crc(bp))
341 		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
342 	else {
343 		fa = xfs_allocbt_verify(bp);
344 		if (fa)
345 			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
346 	}
347 
348 	if (bp->b_error)
349 		trace_xfs_btree_corrupt(bp, _RET_IP_);
350 }
351 
352 static void
353 xfs_allocbt_write_verify(
354 	struct xfs_buf	*bp)
355 {
356 	xfs_failaddr_t	fa;
357 
358 	fa = xfs_allocbt_verify(bp);
359 	if (fa) {
360 		trace_xfs_btree_corrupt(bp, _RET_IP_);
361 		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
362 		return;
363 	}
364 	xfs_btree_sblock_calc_crc(bp);
365 
366 }
367 
368 const struct xfs_buf_ops xfs_bnobt_buf_ops = {
369 	.name = "xfs_bnobt",
370 	.magic = { cpu_to_be32(XFS_ABTB_MAGIC),
371 		   cpu_to_be32(XFS_ABTB_CRC_MAGIC) },
372 	.verify_read = xfs_allocbt_read_verify,
373 	.verify_write = xfs_allocbt_write_verify,
374 	.verify_struct = xfs_allocbt_verify,
375 };
376 
377 const struct xfs_buf_ops xfs_cntbt_buf_ops = {
378 	.name = "xfs_cntbt",
379 	.magic = { cpu_to_be32(XFS_ABTC_MAGIC),
380 		   cpu_to_be32(XFS_ABTC_CRC_MAGIC) },
381 	.verify_read = xfs_allocbt_read_verify,
382 	.verify_write = xfs_allocbt_write_verify,
383 	.verify_struct = xfs_allocbt_verify,
384 };
385 
386 STATIC int
387 xfs_bnobt_keys_inorder(
388 	struct xfs_btree_cur		*cur,
389 	const union xfs_btree_key	*k1,
390 	const union xfs_btree_key	*k2)
391 {
392 	return be32_to_cpu(k1->alloc.ar_startblock) <
393 	       be32_to_cpu(k2->alloc.ar_startblock);
394 }
395 
396 STATIC int
397 xfs_bnobt_recs_inorder(
398 	struct xfs_btree_cur		*cur,
399 	const union xfs_btree_rec	*r1,
400 	const union xfs_btree_rec	*r2)
401 {
402 	return be32_to_cpu(r1->alloc.ar_startblock) +
403 		be32_to_cpu(r1->alloc.ar_blockcount) <=
404 		be32_to_cpu(r2->alloc.ar_startblock);
405 }
406 
407 STATIC int
408 xfs_cntbt_keys_inorder(
409 	struct xfs_btree_cur		*cur,
410 	const union xfs_btree_key	*k1,
411 	const union xfs_btree_key	*k2)
412 {
413 	return be32_to_cpu(k1->alloc.ar_blockcount) <
414 		be32_to_cpu(k2->alloc.ar_blockcount) ||
415 		(k1->alloc.ar_blockcount == k2->alloc.ar_blockcount &&
416 		 be32_to_cpu(k1->alloc.ar_startblock) <
417 		 be32_to_cpu(k2->alloc.ar_startblock));
418 }
419 
420 STATIC int
421 xfs_cntbt_recs_inorder(
422 	struct xfs_btree_cur		*cur,
423 	const union xfs_btree_rec	*r1,
424 	const union xfs_btree_rec	*r2)
425 {
426 	return be32_to_cpu(r1->alloc.ar_blockcount) <
427 		be32_to_cpu(r2->alloc.ar_blockcount) ||
428 		(r1->alloc.ar_blockcount == r2->alloc.ar_blockcount &&
429 		 be32_to_cpu(r1->alloc.ar_startblock) <
430 		 be32_to_cpu(r2->alloc.ar_startblock));
431 }
432 
433 STATIC enum xbtree_key_contig
434 xfs_allocbt_keys_contiguous(
435 	struct xfs_btree_cur		*cur,
436 	const union xfs_btree_key	*key1,
437 	const union xfs_btree_key	*key2,
438 	const union xfs_btree_key	*mask)
439 {
440 	ASSERT(!mask || mask->alloc.ar_startblock);
441 
442 	return xbtree_key_contig(be32_to_cpu(key1->alloc.ar_startblock),
443 				 be32_to_cpu(key2->alloc.ar_startblock));
444 }
445 
446 static const struct xfs_btree_ops xfs_bnobt_ops = {
447 	.rec_len		= sizeof(xfs_alloc_rec_t),
448 	.key_len		= sizeof(xfs_alloc_key_t),
449 
450 	.dup_cursor		= xfs_allocbt_dup_cursor,
451 	.set_root		= xfs_allocbt_set_root,
452 	.alloc_block		= xfs_allocbt_alloc_block,
453 	.free_block		= xfs_allocbt_free_block,
454 	.update_lastrec		= xfs_allocbt_update_lastrec,
455 	.get_minrecs		= xfs_allocbt_get_minrecs,
456 	.get_maxrecs		= xfs_allocbt_get_maxrecs,
457 	.init_key_from_rec	= xfs_allocbt_init_key_from_rec,
458 	.init_high_key_from_rec	= xfs_bnobt_init_high_key_from_rec,
459 	.init_rec_from_cur	= xfs_allocbt_init_rec_from_cur,
460 	.init_ptr_from_cur	= xfs_allocbt_init_ptr_from_cur,
461 	.key_diff		= xfs_bnobt_key_diff,
462 	.buf_ops		= &xfs_bnobt_buf_ops,
463 	.diff_two_keys		= xfs_bnobt_diff_two_keys,
464 	.keys_inorder		= xfs_bnobt_keys_inorder,
465 	.recs_inorder		= xfs_bnobt_recs_inorder,
466 	.keys_contiguous	= xfs_allocbt_keys_contiguous,
467 };
468 
469 static const struct xfs_btree_ops xfs_cntbt_ops = {
470 	.rec_len		= sizeof(xfs_alloc_rec_t),
471 	.key_len		= sizeof(xfs_alloc_key_t),
472 
473 	.dup_cursor		= xfs_allocbt_dup_cursor,
474 	.set_root		= xfs_allocbt_set_root,
475 	.alloc_block		= xfs_allocbt_alloc_block,
476 	.free_block		= xfs_allocbt_free_block,
477 	.update_lastrec		= xfs_allocbt_update_lastrec,
478 	.get_minrecs		= xfs_allocbt_get_minrecs,
479 	.get_maxrecs		= xfs_allocbt_get_maxrecs,
480 	.init_key_from_rec	= xfs_allocbt_init_key_from_rec,
481 	.init_high_key_from_rec	= xfs_cntbt_init_high_key_from_rec,
482 	.init_rec_from_cur	= xfs_allocbt_init_rec_from_cur,
483 	.init_ptr_from_cur	= xfs_allocbt_init_ptr_from_cur,
484 	.key_diff		= xfs_cntbt_key_diff,
485 	.buf_ops		= &xfs_cntbt_buf_ops,
486 	.diff_two_keys		= xfs_cntbt_diff_two_keys,
487 	.keys_inorder		= xfs_cntbt_keys_inorder,
488 	.recs_inorder		= xfs_cntbt_recs_inorder,
489 	.keys_contiguous	= NULL, /* not needed right now */
490 };
491 
492 /* Allocate most of a new allocation btree cursor. */
493 STATIC struct xfs_btree_cur *
494 xfs_allocbt_init_common(
495 	struct xfs_mount	*mp,
496 	struct xfs_trans	*tp,
497 	struct xfs_perag	*pag,
498 	xfs_btnum_t		btnum)
499 {
500 	struct xfs_btree_cur	*cur;
501 
502 	ASSERT(btnum == XFS_BTNUM_BNO || btnum == XFS_BTNUM_CNT);
503 
504 	cur = xfs_btree_alloc_cursor(mp, tp, btnum, mp->m_alloc_maxlevels,
505 			xfs_allocbt_cur_cache);
506 	cur->bc_ag.abt.active = false;
507 
508 	if (btnum == XFS_BTNUM_CNT) {
509 		cur->bc_ops = &xfs_cntbt_ops;
510 		cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_abtc_2);
511 		cur->bc_flags = XFS_BTREE_LASTREC_UPDATE;
512 	} else {
513 		cur->bc_ops = &xfs_bnobt_ops;
514 		cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_abtb_2);
515 	}
516 
517 	cur->bc_ag.pag = xfs_perag_hold(pag);
518 
519 	if (xfs_has_crc(mp))
520 		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
521 
522 	return cur;
523 }
524 
525 /*
526  * Allocate a new allocation btree cursor.
527  */
528 struct xfs_btree_cur *			/* new alloc btree cursor */
529 xfs_allocbt_init_cursor(
530 	struct xfs_mount	*mp,		/* file system mount point */
531 	struct xfs_trans	*tp,		/* transaction pointer */
532 	struct xfs_buf		*agbp,		/* buffer for agf structure */
533 	struct xfs_perag	*pag,
534 	xfs_btnum_t		btnum)		/* btree identifier */
535 {
536 	struct xfs_agf		*agf = agbp->b_addr;
537 	struct xfs_btree_cur	*cur;
538 
539 	cur = xfs_allocbt_init_common(mp, tp, pag, btnum);
540 	if (btnum == XFS_BTNUM_CNT)
541 		cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]);
542 	else
543 		cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]);
544 
545 	cur->bc_ag.agbp = agbp;
546 
547 	return cur;
548 }
549 
550 /* Create a free space btree cursor with a fake root for staging. */
551 struct xfs_btree_cur *
552 xfs_allocbt_stage_cursor(
553 	struct xfs_mount	*mp,
554 	struct xbtree_afakeroot	*afake,
555 	struct xfs_perag	*pag,
556 	xfs_btnum_t		btnum)
557 {
558 	struct xfs_btree_cur	*cur;
559 
560 	cur = xfs_allocbt_init_common(mp, NULL, pag, btnum);
561 	xfs_btree_stage_afakeroot(cur, afake);
562 	return cur;
563 }
564 
565 /*
566  * Install a new free space btree root.  Caller is responsible for invalidating
567  * and freeing the old btree blocks.
568  */
569 void
570 xfs_allocbt_commit_staged_btree(
571 	struct xfs_btree_cur	*cur,
572 	struct xfs_trans	*tp,
573 	struct xfs_buf		*agbp)
574 {
575 	struct xfs_agf		*agf = agbp->b_addr;
576 	struct xbtree_afakeroot	*afake = cur->bc_ag.afake;
577 
578 	ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
579 
580 	agf->agf_roots[cur->bc_btnum] = cpu_to_be32(afake->af_root);
581 	agf->agf_levels[cur->bc_btnum] = cpu_to_be32(afake->af_levels);
582 	xfs_alloc_log_agf(tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
583 
584 	if (cur->bc_btnum == XFS_BTNUM_BNO) {
585 		xfs_btree_commit_afakeroot(cur, tp, agbp, &xfs_bnobt_ops);
586 	} else {
587 		cur->bc_flags |= XFS_BTREE_LASTREC_UPDATE;
588 		xfs_btree_commit_afakeroot(cur, tp, agbp, &xfs_cntbt_ops);
589 	}
590 }
591 
592 /* Calculate number of records in an alloc btree block. */
593 static inline unsigned int
594 xfs_allocbt_block_maxrecs(
595 	unsigned int		blocklen,
596 	bool			leaf)
597 {
598 	if (leaf)
599 		return blocklen / sizeof(xfs_alloc_rec_t);
600 	return blocklen / (sizeof(xfs_alloc_key_t) + sizeof(xfs_alloc_ptr_t));
601 }
602 
603 /*
604  * Calculate number of records in an alloc btree block.
605  */
606 int
607 xfs_allocbt_maxrecs(
608 	struct xfs_mount	*mp,
609 	int			blocklen,
610 	int			leaf)
611 {
612 	blocklen -= XFS_ALLOC_BLOCK_LEN(mp);
613 	return xfs_allocbt_block_maxrecs(blocklen, leaf);
614 }
615 
616 /* Free space btrees are at their largest when every other block is free. */
617 #define XFS_MAX_FREESP_RECORDS	((XFS_MAX_AG_BLOCKS + 1) / 2)
618 
619 /* Compute the max possible height for free space btrees. */
620 unsigned int
621 xfs_allocbt_maxlevels_ondisk(void)
622 {
623 	unsigned int		minrecs[2];
624 	unsigned int		blocklen;
625 
626 	blocklen = min(XFS_MIN_BLOCKSIZE - XFS_BTREE_SBLOCK_LEN,
627 		       XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_SBLOCK_CRC_LEN);
628 
629 	minrecs[0] = xfs_allocbt_block_maxrecs(blocklen, true) / 2;
630 	minrecs[1] = xfs_allocbt_block_maxrecs(blocklen, false) / 2;
631 
632 	return xfs_btree_compute_maxlevels(minrecs, XFS_MAX_FREESP_RECORDS);
633 }
634 
635 /* Calculate the freespace btree size for some records. */
636 xfs_extlen_t
637 xfs_allocbt_calc_size(
638 	struct xfs_mount	*mp,
639 	unsigned long long	len)
640 {
641 	return xfs_btree_calc_size(mp->m_alloc_mnr, len);
642 }
643 
644 int __init
645 xfs_allocbt_init_cur_cache(void)
646 {
647 	xfs_allocbt_cur_cache = kmem_cache_create("xfs_bnobt_cur",
648 			xfs_btree_cur_sizeof(xfs_allocbt_maxlevels_ondisk()),
649 			0, 0, NULL);
650 
651 	if (!xfs_allocbt_cur_cache)
652 		return -ENOMEM;
653 	return 0;
654 }
655 
656 void
657 xfs_allocbt_destroy_cur_cache(void)
658 {
659 	kmem_cache_destroy(xfs_allocbt_cur_cache);
660 	xfs_allocbt_cur_cache = NULL;
661 }
662