xref: /openbmc/linux/fs/xfs/libxfs/xfs_bmap_btree.c (revision ba61bb17)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2000-2003,2005 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_bit.h"
13 #include "xfs_mount.h"
14 #include "xfs_defer.h"
15 #include "xfs_inode.h"
16 #include "xfs_trans.h"
17 #include "xfs_inode_item.h"
18 #include "xfs_alloc.h"
19 #include "xfs_btree.h"
20 #include "xfs_bmap_btree.h"
21 #include "xfs_bmap.h"
22 #include "xfs_error.h"
23 #include "xfs_quota.h"
24 #include "xfs_trace.h"
25 #include "xfs_cksum.h"
26 #include "xfs_rmap.h"
27 
28 /*
29  * Convert on-disk form of btree root to in-memory form.
30  */
31 void
32 xfs_bmdr_to_bmbt(
33 	struct xfs_inode	*ip,
34 	xfs_bmdr_block_t	*dblock,
35 	int			dblocklen,
36 	struct xfs_btree_block	*rblock,
37 	int			rblocklen)
38 {
39 	struct xfs_mount	*mp = ip->i_mount;
40 	int			dmxr;
41 	xfs_bmbt_key_t		*fkp;
42 	__be64			*fpp;
43 	xfs_bmbt_key_t		*tkp;
44 	__be64			*tpp;
45 
46 	xfs_btree_init_block_int(mp, rblock, XFS_BUF_DADDR_NULL,
47 				 XFS_BTNUM_BMAP, 0, 0, ip->i_ino,
48 				 XFS_BTREE_LONG_PTRS);
49 	rblock->bb_level = dblock->bb_level;
50 	ASSERT(be16_to_cpu(rblock->bb_level) > 0);
51 	rblock->bb_numrecs = dblock->bb_numrecs;
52 	dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
53 	fkp = XFS_BMDR_KEY_ADDR(dblock, 1);
54 	tkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
55 	fpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
56 	tpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
57 	dmxr = be16_to_cpu(dblock->bb_numrecs);
58 	memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
59 	memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
60 }
61 
62 void
63 xfs_bmbt_disk_get_all(
64 	struct xfs_bmbt_rec	*rec,
65 	struct xfs_bmbt_irec	*irec)
66 {
67 	uint64_t		l0 = get_unaligned_be64(&rec->l0);
68 	uint64_t		l1 = get_unaligned_be64(&rec->l1);
69 
70 	irec->br_startoff = (l0 & xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
71 	irec->br_startblock = ((l0 & xfs_mask64lo(9)) << 43) | (l1 >> 21);
72 	irec->br_blockcount = l1 & xfs_mask64lo(21);
73 	if (l0 >> (64 - BMBT_EXNTFLAG_BITLEN))
74 		irec->br_state = XFS_EXT_UNWRITTEN;
75 	else
76 		irec->br_state = XFS_EXT_NORM;
77 }
78 
79 /*
80  * Extract the blockcount field from an on disk bmap extent record.
81  */
82 xfs_filblks_t
83 xfs_bmbt_disk_get_blockcount(
84 	xfs_bmbt_rec_t	*r)
85 {
86 	return (xfs_filblks_t)(be64_to_cpu(r->l1) & xfs_mask64lo(21));
87 }
88 
89 /*
90  * Extract the startoff field from a disk format bmap extent record.
91  */
92 xfs_fileoff_t
93 xfs_bmbt_disk_get_startoff(
94 	xfs_bmbt_rec_t	*r)
95 {
96 	return ((xfs_fileoff_t)be64_to_cpu(r->l0) &
97 		 xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
98 }
99 
100 /*
101  * Set all the fields in a bmap extent record from the uncompressed form.
102  */
103 void
104 xfs_bmbt_disk_set_all(
105 	struct xfs_bmbt_rec	*r,
106 	struct xfs_bmbt_irec	*s)
107 {
108 	int			extent_flag = (s->br_state != XFS_EXT_NORM);
109 
110 	ASSERT(s->br_state == XFS_EXT_NORM || s->br_state == XFS_EXT_UNWRITTEN);
111 	ASSERT(!(s->br_startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)));
112 	ASSERT(!(s->br_blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)));
113 	ASSERT(!(s->br_startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)));
114 
115 	put_unaligned_be64(
116 		((xfs_bmbt_rec_base_t)extent_flag << 63) |
117 		 ((xfs_bmbt_rec_base_t)s->br_startoff << 9) |
118 		 ((xfs_bmbt_rec_base_t)s->br_startblock >> 43), &r->l0);
119 	put_unaligned_be64(
120 		((xfs_bmbt_rec_base_t)s->br_startblock << 21) |
121 		 ((xfs_bmbt_rec_base_t)s->br_blockcount &
122 		  (xfs_bmbt_rec_base_t)xfs_mask64lo(21)), &r->l1);
123 }
124 
125 /*
126  * Convert in-memory form of btree root to on-disk form.
127  */
128 void
129 xfs_bmbt_to_bmdr(
130 	struct xfs_mount	*mp,
131 	struct xfs_btree_block	*rblock,
132 	int			rblocklen,
133 	xfs_bmdr_block_t	*dblock,
134 	int			dblocklen)
135 {
136 	int			dmxr;
137 	xfs_bmbt_key_t		*fkp;
138 	__be64			*fpp;
139 	xfs_bmbt_key_t		*tkp;
140 	__be64			*tpp;
141 
142 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
143 		ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_CRC_MAGIC));
144 		ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid,
145 		       &mp->m_sb.sb_meta_uuid));
146 		ASSERT(rblock->bb_u.l.bb_blkno ==
147 		       cpu_to_be64(XFS_BUF_DADDR_NULL));
148 	} else
149 		ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_MAGIC));
150 	ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
151 	ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
152 	ASSERT(rblock->bb_level != 0);
153 	dblock->bb_level = rblock->bb_level;
154 	dblock->bb_numrecs = rblock->bb_numrecs;
155 	dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
156 	fkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
157 	tkp = XFS_BMDR_KEY_ADDR(dblock, 1);
158 	fpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
159 	tpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
160 	dmxr = be16_to_cpu(dblock->bb_numrecs);
161 	memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
162 	memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
163 }
164 
165 STATIC struct xfs_btree_cur *
166 xfs_bmbt_dup_cursor(
167 	struct xfs_btree_cur	*cur)
168 {
169 	struct xfs_btree_cur	*new;
170 
171 	new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
172 			cur->bc_private.b.ip, cur->bc_private.b.whichfork);
173 
174 	/*
175 	 * Copy the firstblock, dfops, and flags values,
176 	 * since init cursor doesn't get them.
177 	 */
178 	new->bc_private.b.firstblock = cur->bc_private.b.firstblock;
179 	new->bc_private.b.dfops = cur->bc_private.b.dfops;
180 	new->bc_private.b.flags = cur->bc_private.b.flags;
181 
182 	return new;
183 }
184 
185 STATIC void
186 xfs_bmbt_update_cursor(
187 	struct xfs_btree_cur	*src,
188 	struct xfs_btree_cur	*dst)
189 {
190 	ASSERT((dst->bc_private.b.firstblock != NULLFSBLOCK) ||
191 	       (dst->bc_private.b.ip->i_d.di_flags & XFS_DIFLAG_REALTIME));
192 	ASSERT(dst->bc_private.b.dfops == src->bc_private.b.dfops);
193 
194 	dst->bc_private.b.allocated += src->bc_private.b.allocated;
195 	dst->bc_private.b.firstblock = src->bc_private.b.firstblock;
196 
197 	src->bc_private.b.allocated = 0;
198 }
199 
200 STATIC int
201 xfs_bmbt_alloc_block(
202 	struct xfs_btree_cur	*cur,
203 	union xfs_btree_ptr	*start,
204 	union xfs_btree_ptr	*new,
205 	int			*stat)
206 {
207 	xfs_alloc_arg_t		args;		/* block allocation args */
208 	int			error;		/* error return value */
209 
210 	memset(&args, 0, sizeof(args));
211 	args.tp = cur->bc_tp;
212 	args.mp = cur->bc_mp;
213 	args.fsbno = cur->bc_private.b.firstblock;
214 	args.firstblock = args.fsbno;
215 	xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_private.b.ip->i_ino,
216 			cur->bc_private.b.whichfork);
217 
218 	if (args.fsbno == NULLFSBLOCK) {
219 		args.fsbno = be64_to_cpu(start->l);
220 		args.type = XFS_ALLOCTYPE_START_BNO;
221 		/*
222 		 * Make sure there is sufficient room left in the AG to
223 		 * complete a full tree split for an extent insert.  If
224 		 * we are converting the middle part of an extent then
225 		 * we may need space for two tree splits.
226 		 *
227 		 * We are relying on the caller to make the correct block
228 		 * reservation for this operation to succeed.  If the
229 		 * reservation amount is insufficient then we may fail a
230 		 * block allocation here and corrupt the filesystem.
231 		 */
232 		args.minleft = args.tp->t_blk_res;
233 	} else if (cur->bc_private.b.dfops->dop_low) {
234 		args.type = XFS_ALLOCTYPE_START_BNO;
235 	} else {
236 		args.type = XFS_ALLOCTYPE_NEAR_BNO;
237 	}
238 
239 	args.minlen = args.maxlen = args.prod = 1;
240 	args.wasdel = cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL;
241 	if (!args.wasdel && args.tp->t_blk_res == 0) {
242 		error = -ENOSPC;
243 		goto error0;
244 	}
245 	error = xfs_alloc_vextent(&args);
246 	if (error)
247 		goto error0;
248 
249 	if (args.fsbno == NULLFSBLOCK && args.minleft) {
250 		/*
251 		 * Could not find an AG with enough free space to satisfy
252 		 * a full btree split.  Try again and if
253 		 * successful activate the lowspace algorithm.
254 		 */
255 		args.fsbno = 0;
256 		args.type = XFS_ALLOCTYPE_FIRST_AG;
257 		error = xfs_alloc_vextent(&args);
258 		if (error)
259 			goto error0;
260 		cur->bc_private.b.dfops->dop_low = true;
261 	}
262 	if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
263 		*stat = 0;
264 		return 0;
265 	}
266 
267 	ASSERT(args.len == 1);
268 	cur->bc_private.b.firstblock = args.fsbno;
269 	cur->bc_private.b.allocated++;
270 	cur->bc_private.b.ip->i_d.di_nblocks++;
271 	xfs_trans_log_inode(args.tp, cur->bc_private.b.ip, XFS_ILOG_CORE);
272 	xfs_trans_mod_dquot_byino(args.tp, cur->bc_private.b.ip,
273 			XFS_TRANS_DQ_BCOUNT, 1L);
274 
275 	new->l = cpu_to_be64(args.fsbno);
276 
277 	*stat = 1;
278 	return 0;
279 
280  error0:
281 	return error;
282 }
283 
284 STATIC int
285 xfs_bmbt_free_block(
286 	struct xfs_btree_cur	*cur,
287 	struct xfs_buf		*bp)
288 {
289 	struct xfs_mount	*mp = cur->bc_mp;
290 	struct xfs_inode	*ip = cur->bc_private.b.ip;
291 	struct xfs_trans	*tp = cur->bc_tp;
292 	xfs_fsblock_t		fsbno = XFS_DADDR_TO_FSB(mp, XFS_BUF_ADDR(bp));
293 	struct xfs_owner_info	oinfo;
294 
295 	xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_private.b.whichfork);
296 	xfs_bmap_add_free(mp, cur->bc_private.b.dfops, fsbno, 1, &oinfo);
297 	ip->i_d.di_nblocks--;
298 
299 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
300 	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
301 	return 0;
302 }
303 
304 STATIC int
305 xfs_bmbt_get_minrecs(
306 	struct xfs_btree_cur	*cur,
307 	int			level)
308 {
309 	if (level == cur->bc_nlevels - 1) {
310 		struct xfs_ifork	*ifp;
311 
312 		ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
313 				    cur->bc_private.b.whichfork);
314 
315 		return xfs_bmbt_maxrecs(cur->bc_mp,
316 					ifp->if_broot_bytes, level == 0) / 2;
317 	}
318 
319 	return cur->bc_mp->m_bmap_dmnr[level != 0];
320 }
321 
322 int
323 xfs_bmbt_get_maxrecs(
324 	struct xfs_btree_cur	*cur,
325 	int			level)
326 {
327 	if (level == cur->bc_nlevels - 1) {
328 		struct xfs_ifork	*ifp;
329 
330 		ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
331 				    cur->bc_private.b.whichfork);
332 
333 		return xfs_bmbt_maxrecs(cur->bc_mp,
334 					ifp->if_broot_bytes, level == 0);
335 	}
336 
337 	return cur->bc_mp->m_bmap_dmxr[level != 0];
338 
339 }
340 
341 /*
342  * Get the maximum records we could store in the on-disk format.
343  *
344  * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
345  * for the root node this checks the available space in the dinode fork
346  * so that we can resize the in-memory buffer to match it.  After a
347  * resize to the maximum size this function returns the same value
348  * as xfs_bmbt_get_maxrecs for the root node, too.
349  */
350 STATIC int
351 xfs_bmbt_get_dmaxrecs(
352 	struct xfs_btree_cur	*cur,
353 	int			level)
354 {
355 	if (level != cur->bc_nlevels - 1)
356 		return cur->bc_mp->m_bmap_dmxr[level != 0];
357 	return xfs_bmdr_maxrecs(cur->bc_private.b.forksize, level == 0);
358 }
359 
360 STATIC void
361 xfs_bmbt_init_key_from_rec(
362 	union xfs_btree_key	*key,
363 	union xfs_btree_rec	*rec)
364 {
365 	key->bmbt.br_startoff =
366 		cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
367 }
368 
369 STATIC void
370 xfs_bmbt_init_high_key_from_rec(
371 	union xfs_btree_key	*key,
372 	union xfs_btree_rec	*rec)
373 {
374 	key->bmbt.br_startoff = cpu_to_be64(
375 			xfs_bmbt_disk_get_startoff(&rec->bmbt) +
376 			xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
377 }
378 
379 STATIC void
380 xfs_bmbt_init_rec_from_cur(
381 	struct xfs_btree_cur	*cur,
382 	union xfs_btree_rec	*rec)
383 {
384 	xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
385 }
386 
387 STATIC void
388 xfs_bmbt_init_ptr_from_cur(
389 	struct xfs_btree_cur	*cur,
390 	union xfs_btree_ptr	*ptr)
391 {
392 	ptr->l = 0;
393 }
394 
395 STATIC int64_t
396 xfs_bmbt_key_diff(
397 	struct xfs_btree_cur	*cur,
398 	union xfs_btree_key	*key)
399 {
400 	return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
401 				      cur->bc_rec.b.br_startoff;
402 }
403 
404 STATIC int64_t
405 xfs_bmbt_diff_two_keys(
406 	struct xfs_btree_cur	*cur,
407 	union xfs_btree_key	*k1,
408 	union xfs_btree_key	*k2)
409 {
410 	return (int64_t)be64_to_cpu(k1->bmbt.br_startoff) -
411 			  be64_to_cpu(k2->bmbt.br_startoff);
412 }
413 
414 static xfs_failaddr_t
415 xfs_bmbt_verify(
416 	struct xfs_buf		*bp)
417 {
418 	struct xfs_mount	*mp = bp->b_target->bt_mount;
419 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
420 	xfs_failaddr_t		fa;
421 	unsigned int		level;
422 
423 	switch (block->bb_magic) {
424 	case cpu_to_be32(XFS_BMAP_CRC_MAGIC):
425 		/*
426 		 * XXX: need a better way of verifying the owner here. Right now
427 		 * just make sure there has been one set.
428 		 */
429 		fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
430 		if (fa)
431 			return fa;
432 		/* fall through */
433 	case cpu_to_be32(XFS_BMAP_MAGIC):
434 		break;
435 	default:
436 		return __this_address;
437 	}
438 
439 	/*
440 	 * numrecs and level verification.
441 	 *
442 	 * We don't know what fork we belong to, so just verify that the level
443 	 * is less than the maximum of the two. Later checks will be more
444 	 * precise.
445 	 */
446 	level = be16_to_cpu(block->bb_level);
447 	if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
448 		return __this_address;
449 
450 	return xfs_btree_lblock_verify(bp, mp->m_bmap_dmxr[level != 0]);
451 }
452 
453 static void
454 xfs_bmbt_read_verify(
455 	struct xfs_buf	*bp)
456 {
457 	xfs_failaddr_t	fa;
458 
459 	if (!xfs_btree_lblock_verify_crc(bp))
460 		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
461 	else {
462 		fa = xfs_bmbt_verify(bp);
463 		if (fa)
464 			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
465 	}
466 
467 	if (bp->b_error)
468 		trace_xfs_btree_corrupt(bp, _RET_IP_);
469 }
470 
471 static void
472 xfs_bmbt_write_verify(
473 	struct xfs_buf	*bp)
474 {
475 	xfs_failaddr_t	fa;
476 
477 	fa = xfs_bmbt_verify(bp);
478 	if (fa) {
479 		trace_xfs_btree_corrupt(bp, _RET_IP_);
480 		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
481 		return;
482 	}
483 	xfs_btree_lblock_calc_crc(bp);
484 }
485 
486 const struct xfs_buf_ops xfs_bmbt_buf_ops = {
487 	.name = "xfs_bmbt",
488 	.verify_read = xfs_bmbt_read_verify,
489 	.verify_write = xfs_bmbt_write_verify,
490 	.verify_struct = xfs_bmbt_verify,
491 };
492 
493 
494 STATIC int
495 xfs_bmbt_keys_inorder(
496 	struct xfs_btree_cur	*cur,
497 	union xfs_btree_key	*k1,
498 	union xfs_btree_key	*k2)
499 {
500 	return be64_to_cpu(k1->bmbt.br_startoff) <
501 		be64_to_cpu(k2->bmbt.br_startoff);
502 }
503 
504 STATIC int
505 xfs_bmbt_recs_inorder(
506 	struct xfs_btree_cur	*cur,
507 	union xfs_btree_rec	*r1,
508 	union xfs_btree_rec	*r2)
509 {
510 	return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
511 		xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
512 		xfs_bmbt_disk_get_startoff(&r2->bmbt);
513 }
514 
515 static const struct xfs_btree_ops xfs_bmbt_ops = {
516 	.rec_len		= sizeof(xfs_bmbt_rec_t),
517 	.key_len		= sizeof(xfs_bmbt_key_t),
518 
519 	.dup_cursor		= xfs_bmbt_dup_cursor,
520 	.update_cursor		= xfs_bmbt_update_cursor,
521 	.alloc_block		= xfs_bmbt_alloc_block,
522 	.free_block		= xfs_bmbt_free_block,
523 	.get_maxrecs		= xfs_bmbt_get_maxrecs,
524 	.get_minrecs		= xfs_bmbt_get_minrecs,
525 	.get_dmaxrecs		= xfs_bmbt_get_dmaxrecs,
526 	.init_key_from_rec	= xfs_bmbt_init_key_from_rec,
527 	.init_high_key_from_rec	= xfs_bmbt_init_high_key_from_rec,
528 	.init_rec_from_cur	= xfs_bmbt_init_rec_from_cur,
529 	.init_ptr_from_cur	= xfs_bmbt_init_ptr_from_cur,
530 	.key_diff		= xfs_bmbt_key_diff,
531 	.diff_two_keys		= xfs_bmbt_diff_two_keys,
532 	.buf_ops		= &xfs_bmbt_buf_ops,
533 	.keys_inorder		= xfs_bmbt_keys_inorder,
534 	.recs_inorder		= xfs_bmbt_recs_inorder,
535 };
536 
537 /*
538  * Allocate a new bmap btree cursor.
539  */
540 struct xfs_btree_cur *				/* new bmap btree cursor */
541 xfs_bmbt_init_cursor(
542 	struct xfs_mount	*mp,		/* file system mount point */
543 	struct xfs_trans	*tp,		/* transaction pointer */
544 	struct xfs_inode	*ip,		/* inode owning the btree */
545 	int			whichfork)	/* data or attr fork */
546 {
547 	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
548 	struct xfs_btree_cur	*cur;
549 	ASSERT(whichfork != XFS_COW_FORK);
550 
551 	cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
552 
553 	cur->bc_tp = tp;
554 	cur->bc_mp = mp;
555 	cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
556 	cur->bc_btnum = XFS_BTNUM_BMAP;
557 	cur->bc_blocklog = mp->m_sb.sb_blocklog;
558 	cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_bmbt_2);
559 
560 	cur->bc_ops = &xfs_bmbt_ops;
561 	cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
562 	if (xfs_sb_version_hascrc(&mp->m_sb))
563 		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
564 
565 	cur->bc_private.b.forksize = XFS_IFORK_SIZE(ip, whichfork);
566 	cur->bc_private.b.ip = ip;
567 	cur->bc_private.b.firstblock = NULLFSBLOCK;
568 	cur->bc_private.b.dfops = NULL;
569 	cur->bc_private.b.allocated = 0;
570 	cur->bc_private.b.flags = 0;
571 	cur->bc_private.b.whichfork = whichfork;
572 
573 	return cur;
574 }
575 
576 /*
577  * Calculate number of records in a bmap btree block.
578  */
579 int
580 xfs_bmbt_maxrecs(
581 	struct xfs_mount	*mp,
582 	int			blocklen,
583 	int			leaf)
584 {
585 	blocklen -= XFS_BMBT_BLOCK_LEN(mp);
586 
587 	if (leaf)
588 		return blocklen / sizeof(xfs_bmbt_rec_t);
589 	return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
590 }
591 
592 /*
593  * Calculate number of records in a bmap btree inode root.
594  */
595 int
596 xfs_bmdr_maxrecs(
597 	int			blocklen,
598 	int			leaf)
599 {
600 	blocklen -= sizeof(xfs_bmdr_block_t);
601 
602 	if (leaf)
603 		return blocklen / sizeof(xfs_bmdr_rec_t);
604 	return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
605 }
606 
607 /*
608  * Change the owner of a btree format fork fo the inode passed in. Change it to
609  * the owner of that is passed in so that we can change owners before or after
610  * we switch forks between inodes. The operation that the caller is doing will
611  * determine whether is needs to change owner before or after the switch.
612  *
613  * For demand paged transactional modification, the fork switch should be done
614  * after reading in all the blocks, modifying them and pinning them in the
615  * transaction. For modification when the buffers are already pinned in memory,
616  * the fork switch can be done before changing the owner as we won't need to
617  * validate the owner until the btree buffers are unpinned and writes can occur
618  * again.
619  *
620  * For recovery based ownership change, there is no transactional context and
621  * so a buffer list must be supplied so that we can record the buffers that we
622  * modified for the caller to issue IO on.
623  */
624 int
625 xfs_bmbt_change_owner(
626 	struct xfs_trans	*tp,
627 	struct xfs_inode	*ip,
628 	int			whichfork,
629 	xfs_ino_t		new_owner,
630 	struct list_head	*buffer_list)
631 {
632 	struct xfs_btree_cur	*cur;
633 	int			error;
634 
635 	ASSERT(tp || buffer_list);
636 	ASSERT(!(tp && buffer_list));
637 	if (whichfork == XFS_DATA_FORK)
638 		ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_BTREE);
639 	else
640 		ASSERT(ip->i_d.di_aformat == XFS_DINODE_FMT_BTREE);
641 
642 	cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
643 	if (!cur)
644 		return -ENOMEM;
645 	cur->bc_private.b.flags |= XFS_BTCUR_BPRV_INVALID_OWNER;
646 
647 	error = xfs_btree_change_owner(cur, new_owner, buffer_list);
648 	xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
649 	return error;
650 }
651 
652 /* Calculate the bmap btree size for some records. */
653 unsigned long long
654 xfs_bmbt_calc_size(
655 	struct xfs_mount	*mp,
656 	unsigned long long	len)
657 {
658 	return xfs_btree_calc_size(mp->m_bmap_dmnr, len);
659 }
660