xref: /linux/fs/xfs/libxfs/xfs_alloc_btree.c (revision d7b4e3287ca3a7baf66efd9158498e551a9550da)
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 		unsigned int	maxlevel = pag->pagf_levels[btnum];
327 
328 #ifdef CONFIG_XFS_ONLINE_REPAIR
329 		/*
330 		 * Online repair could be rewriting the free space btrees, so
331 		 * we'll validate against the larger of either tree while this
332 		 * is going on.
333 		 */
334 		maxlevel = max_t(unsigned int, maxlevel,
335 				 pag->pagf_repair_levels[btnum]);
336 #endif
337 		if (level >= maxlevel)
338 			return __this_address;
339 	} else if (level >= mp->m_alloc_maxlevels)
340 		return __this_address;
341 
342 	return xfs_btree_sblock_verify(bp, mp->m_alloc_mxr[level != 0]);
343 }
344 
345 static void
346 xfs_allocbt_read_verify(
347 	struct xfs_buf	*bp)
348 {
349 	xfs_failaddr_t	fa;
350 
351 	if (!xfs_btree_sblock_verify_crc(bp))
352 		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
353 	else {
354 		fa = xfs_allocbt_verify(bp);
355 		if (fa)
356 			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
357 	}
358 
359 	if (bp->b_error)
360 		trace_xfs_btree_corrupt(bp, _RET_IP_);
361 }
362 
363 static void
364 xfs_allocbt_write_verify(
365 	struct xfs_buf	*bp)
366 {
367 	xfs_failaddr_t	fa;
368 
369 	fa = xfs_allocbt_verify(bp);
370 	if (fa) {
371 		trace_xfs_btree_corrupt(bp, _RET_IP_);
372 		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
373 		return;
374 	}
375 	xfs_btree_sblock_calc_crc(bp);
376 
377 }
378 
379 const struct xfs_buf_ops xfs_bnobt_buf_ops = {
380 	.name = "xfs_bnobt",
381 	.magic = { cpu_to_be32(XFS_ABTB_MAGIC),
382 		   cpu_to_be32(XFS_ABTB_CRC_MAGIC) },
383 	.verify_read = xfs_allocbt_read_verify,
384 	.verify_write = xfs_allocbt_write_verify,
385 	.verify_struct = xfs_allocbt_verify,
386 };
387 
388 const struct xfs_buf_ops xfs_cntbt_buf_ops = {
389 	.name = "xfs_cntbt",
390 	.magic = { cpu_to_be32(XFS_ABTC_MAGIC),
391 		   cpu_to_be32(XFS_ABTC_CRC_MAGIC) },
392 	.verify_read = xfs_allocbt_read_verify,
393 	.verify_write = xfs_allocbt_write_verify,
394 	.verify_struct = xfs_allocbt_verify,
395 };
396 
397 STATIC int
398 xfs_bnobt_keys_inorder(
399 	struct xfs_btree_cur		*cur,
400 	const union xfs_btree_key	*k1,
401 	const union xfs_btree_key	*k2)
402 {
403 	return be32_to_cpu(k1->alloc.ar_startblock) <
404 	       be32_to_cpu(k2->alloc.ar_startblock);
405 }
406 
407 STATIC int
408 xfs_bnobt_recs_inorder(
409 	struct xfs_btree_cur		*cur,
410 	const union xfs_btree_rec	*r1,
411 	const union xfs_btree_rec	*r2)
412 {
413 	return be32_to_cpu(r1->alloc.ar_startblock) +
414 		be32_to_cpu(r1->alloc.ar_blockcount) <=
415 		be32_to_cpu(r2->alloc.ar_startblock);
416 }
417 
418 STATIC int
419 xfs_cntbt_keys_inorder(
420 	struct xfs_btree_cur		*cur,
421 	const union xfs_btree_key	*k1,
422 	const union xfs_btree_key	*k2)
423 {
424 	return be32_to_cpu(k1->alloc.ar_blockcount) <
425 		be32_to_cpu(k2->alloc.ar_blockcount) ||
426 		(k1->alloc.ar_blockcount == k2->alloc.ar_blockcount &&
427 		 be32_to_cpu(k1->alloc.ar_startblock) <
428 		 be32_to_cpu(k2->alloc.ar_startblock));
429 }
430 
431 STATIC int
432 xfs_cntbt_recs_inorder(
433 	struct xfs_btree_cur		*cur,
434 	const union xfs_btree_rec	*r1,
435 	const union xfs_btree_rec	*r2)
436 {
437 	return be32_to_cpu(r1->alloc.ar_blockcount) <
438 		be32_to_cpu(r2->alloc.ar_blockcount) ||
439 		(r1->alloc.ar_blockcount == r2->alloc.ar_blockcount &&
440 		 be32_to_cpu(r1->alloc.ar_startblock) <
441 		 be32_to_cpu(r2->alloc.ar_startblock));
442 }
443 
444 STATIC enum xbtree_key_contig
445 xfs_allocbt_keys_contiguous(
446 	struct xfs_btree_cur		*cur,
447 	const union xfs_btree_key	*key1,
448 	const union xfs_btree_key	*key2,
449 	const union xfs_btree_key	*mask)
450 {
451 	ASSERT(!mask || mask->alloc.ar_startblock);
452 
453 	return xbtree_key_contig(be32_to_cpu(key1->alloc.ar_startblock),
454 				 be32_to_cpu(key2->alloc.ar_startblock));
455 }
456 
457 static const struct xfs_btree_ops xfs_bnobt_ops = {
458 	.rec_len		= sizeof(xfs_alloc_rec_t),
459 	.key_len		= sizeof(xfs_alloc_key_t),
460 
461 	.dup_cursor		= xfs_allocbt_dup_cursor,
462 	.set_root		= xfs_allocbt_set_root,
463 	.alloc_block		= xfs_allocbt_alloc_block,
464 	.free_block		= xfs_allocbt_free_block,
465 	.update_lastrec		= xfs_allocbt_update_lastrec,
466 	.get_minrecs		= xfs_allocbt_get_minrecs,
467 	.get_maxrecs		= xfs_allocbt_get_maxrecs,
468 	.init_key_from_rec	= xfs_allocbt_init_key_from_rec,
469 	.init_high_key_from_rec	= xfs_bnobt_init_high_key_from_rec,
470 	.init_rec_from_cur	= xfs_allocbt_init_rec_from_cur,
471 	.init_ptr_from_cur	= xfs_allocbt_init_ptr_from_cur,
472 	.key_diff		= xfs_bnobt_key_diff,
473 	.buf_ops		= &xfs_bnobt_buf_ops,
474 	.diff_two_keys		= xfs_bnobt_diff_two_keys,
475 	.keys_inorder		= xfs_bnobt_keys_inorder,
476 	.recs_inorder		= xfs_bnobt_recs_inorder,
477 	.keys_contiguous	= xfs_allocbt_keys_contiguous,
478 };
479 
480 static const struct xfs_btree_ops xfs_cntbt_ops = {
481 	.rec_len		= sizeof(xfs_alloc_rec_t),
482 	.key_len		= sizeof(xfs_alloc_key_t),
483 
484 	.dup_cursor		= xfs_allocbt_dup_cursor,
485 	.set_root		= xfs_allocbt_set_root,
486 	.alloc_block		= xfs_allocbt_alloc_block,
487 	.free_block		= xfs_allocbt_free_block,
488 	.update_lastrec		= xfs_allocbt_update_lastrec,
489 	.get_minrecs		= xfs_allocbt_get_minrecs,
490 	.get_maxrecs		= xfs_allocbt_get_maxrecs,
491 	.init_key_from_rec	= xfs_allocbt_init_key_from_rec,
492 	.init_high_key_from_rec	= xfs_cntbt_init_high_key_from_rec,
493 	.init_rec_from_cur	= xfs_allocbt_init_rec_from_cur,
494 	.init_ptr_from_cur	= xfs_allocbt_init_ptr_from_cur,
495 	.key_diff		= xfs_cntbt_key_diff,
496 	.buf_ops		= &xfs_cntbt_buf_ops,
497 	.diff_two_keys		= xfs_cntbt_diff_two_keys,
498 	.keys_inorder		= xfs_cntbt_keys_inorder,
499 	.recs_inorder		= xfs_cntbt_recs_inorder,
500 	.keys_contiguous	= NULL, /* not needed right now */
501 };
502 
503 /* Allocate most of a new allocation btree cursor. */
504 STATIC struct xfs_btree_cur *
505 xfs_allocbt_init_common(
506 	struct xfs_mount	*mp,
507 	struct xfs_trans	*tp,
508 	struct xfs_perag	*pag,
509 	xfs_btnum_t		btnum)
510 {
511 	struct xfs_btree_cur	*cur;
512 
513 	ASSERT(btnum == XFS_BTNUM_BNO || btnum == XFS_BTNUM_CNT);
514 
515 	cur = xfs_btree_alloc_cursor(mp, tp, btnum, mp->m_alloc_maxlevels,
516 			xfs_allocbt_cur_cache);
517 	cur->bc_ag.abt.active = false;
518 
519 	if (btnum == XFS_BTNUM_CNT) {
520 		cur->bc_ops = &xfs_cntbt_ops;
521 		cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_abtc_2);
522 		cur->bc_flags = XFS_BTREE_LASTREC_UPDATE;
523 	} else {
524 		cur->bc_ops = &xfs_bnobt_ops;
525 		cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_abtb_2);
526 	}
527 
528 	cur->bc_ag.pag = xfs_perag_hold(pag);
529 
530 	if (xfs_has_crc(mp))
531 		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
532 
533 	return cur;
534 }
535 
536 /*
537  * Allocate a new allocation btree cursor.
538  */
539 struct xfs_btree_cur *			/* new alloc btree cursor */
540 xfs_allocbt_init_cursor(
541 	struct xfs_mount	*mp,		/* file system mount point */
542 	struct xfs_trans	*tp,		/* transaction pointer */
543 	struct xfs_buf		*agbp,		/* buffer for agf structure */
544 	struct xfs_perag	*pag,
545 	xfs_btnum_t		btnum)		/* btree identifier */
546 {
547 	struct xfs_agf		*agf = agbp->b_addr;
548 	struct xfs_btree_cur	*cur;
549 
550 	cur = xfs_allocbt_init_common(mp, tp, pag, btnum);
551 	if (btnum == XFS_BTNUM_CNT)
552 		cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_CNT]);
553 	else
554 		cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_BNO]);
555 
556 	cur->bc_ag.agbp = agbp;
557 
558 	return cur;
559 }
560 
561 /* Create a free space btree cursor with a fake root for staging. */
562 struct xfs_btree_cur *
563 xfs_allocbt_stage_cursor(
564 	struct xfs_mount	*mp,
565 	struct xbtree_afakeroot	*afake,
566 	struct xfs_perag	*pag,
567 	xfs_btnum_t		btnum)
568 {
569 	struct xfs_btree_cur	*cur;
570 
571 	cur = xfs_allocbt_init_common(mp, NULL, pag, btnum);
572 	xfs_btree_stage_afakeroot(cur, afake);
573 	return cur;
574 }
575 
576 /*
577  * Install a new free space btree root.  Caller is responsible for invalidating
578  * and freeing the old btree blocks.
579  */
580 void
581 xfs_allocbt_commit_staged_btree(
582 	struct xfs_btree_cur	*cur,
583 	struct xfs_trans	*tp,
584 	struct xfs_buf		*agbp)
585 {
586 	struct xfs_agf		*agf = agbp->b_addr;
587 	struct xbtree_afakeroot	*afake = cur->bc_ag.afake;
588 
589 	ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
590 
591 	agf->agf_roots[cur->bc_btnum] = cpu_to_be32(afake->af_root);
592 	agf->agf_levels[cur->bc_btnum] = cpu_to_be32(afake->af_levels);
593 	xfs_alloc_log_agf(tp, agbp, XFS_AGF_ROOTS | XFS_AGF_LEVELS);
594 
595 	if (cur->bc_btnum == XFS_BTNUM_BNO) {
596 		xfs_btree_commit_afakeroot(cur, tp, agbp, &xfs_bnobt_ops);
597 	} else {
598 		cur->bc_flags |= XFS_BTREE_LASTREC_UPDATE;
599 		xfs_btree_commit_afakeroot(cur, tp, agbp, &xfs_cntbt_ops);
600 	}
601 }
602 
603 /* Calculate number of records in an alloc btree block. */
604 static inline unsigned int
605 xfs_allocbt_block_maxrecs(
606 	unsigned int		blocklen,
607 	bool			leaf)
608 {
609 	if (leaf)
610 		return blocklen / sizeof(xfs_alloc_rec_t);
611 	return blocklen / (sizeof(xfs_alloc_key_t) + sizeof(xfs_alloc_ptr_t));
612 }
613 
614 /*
615  * Calculate number of records in an alloc btree block.
616  */
617 int
618 xfs_allocbt_maxrecs(
619 	struct xfs_mount	*mp,
620 	int			blocklen,
621 	int			leaf)
622 {
623 	blocklen -= XFS_ALLOC_BLOCK_LEN(mp);
624 	return xfs_allocbt_block_maxrecs(blocklen, leaf);
625 }
626 
627 /* Free space btrees are at their largest when every other block is free. */
628 #define XFS_MAX_FREESP_RECORDS	((XFS_MAX_AG_BLOCKS + 1) / 2)
629 
630 /* Compute the max possible height for free space btrees. */
631 unsigned int
632 xfs_allocbt_maxlevels_ondisk(void)
633 {
634 	unsigned int		minrecs[2];
635 	unsigned int		blocklen;
636 
637 	blocklen = min(XFS_MIN_BLOCKSIZE - XFS_BTREE_SBLOCK_LEN,
638 		       XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_SBLOCK_CRC_LEN);
639 
640 	minrecs[0] = xfs_allocbt_block_maxrecs(blocklen, true) / 2;
641 	minrecs[1] = xfs_allocbt_block_maxrecs(blocklen, false) / 2;
642 
643 	return xfs_btree_compute_maxlevels(minrecs, XFS_MAX_FREESP_RECORDS);
644 }
645 
646 /* Calculate the freespace btree size for some records. */
647 xfs_extlen_t
648 xfs_allocbt_calc_size(
649 	struct xfs_mount	*mp,
650 	unsigned long long	len)
651 {
652 	return xfs_btree_calc_size(mp->m_alloc_mnr, len);
653 }
654 
655 int __init
656 xfs_allocbt_init_cur_cache(void)
657 {
658 	xfs_allocbt_cur_cache = kmem_cache_create("xfs_bnobt_cur",
659 			xfs_btree_cur_sizeof(xfs_allocbt_maxlevels_ondisk()),
660 			0, 0, NULL);
661 
662 	if (!xfs_allocbt_cur_cache)
663 		return -ENOMEM;
664 	return 0;
665 }
666 
667 void
668 xfs_allocbt_destroy_cur_cache(void)
669 {
670 	kmem_cache_destroy(xfs_allocbt_cur_cache);
671 	xfs_allocbt_cur_cache = NULL;
672 }
673