xref: /linux/fs/xfs/libxfs/xfs_bmap_btree.c (revision b77e0ce62d63a761ffb7f7245a215a49f5921c2f)
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_inode.h"
15 #include "xfs_trans.h"
16 #include "xfs_alloc.h"
17 #include "xfs_btree.h"
18 #include "xfs_bmap_btree.h"
19 #include "xfs_bmap.h"
20 #include "xfs_error.h"
21 #include "xfs_quota.h"
22 #include "xfs_trace.h"
23 #include "xfs_rmap.h"
24 
25 /*
26  * Convert on-disk form of btree root to in-memory form.
27  */
28 void
29 xfs_bmdr_to_bmbt(
30 	struct xfs_inode	*ip,
31 	xfs_bmdr_block_t	*dblock,
32 	int			dblocklen,
33 	struct xfs_btree_block	*rblock,
34 	int			rblocklen)
35 {
36 	struct xfs_mount	*mp = ip->i_mount;
37 	int			dmxr;
38 	xfs_bmbt_key_t		*fkp;
39 	__be64			*fpp;
40 	xfs_bmbt_key_t		*tkp;
41 	__be64			*tpp;
42 
43 	xfs_btree_init_block_int(mp, rblock, XFS_BUF_DADDR_NULL,
44 				 XFS_BTNUM_BMAP, 0, 0, ip->i_ino,
45 				 XFS_BTREE_LONG_PTRS);
46 	rblock->bb_level = dblock->bb_level;
47 	ASSERT(be16_to_cpu(rblock->bb_level) > 0);
48 	rblock->bb_numrecs = dblock->bb_numrecs;
49 	dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
50 	fkp = XFS_BMDR_KEY_ADDR(dblock, 1);
51 	tkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
52 	fpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
53 	tpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
54 	dmxr = be16_to_cpu(dblock->bb_numrecs);
55 	memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
56 	memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
57 }
58 
59 void
60 xfs_bmbt_disk_get_all(
61 	struct xfs_bmbt_rec	*rec,
62 	struct xfs_bmbt_irec	*irec)
63 {
64 	uint64_t		l0 = get_unaligned_be64(&rec->l0);
65 	uint64_t		l1 = get_unaligned_be64(&rec->l1);
66 
67 	irec->br_startoff = (l0 & xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
68 	irec->br_startblock = ((l0 & xfs_mask64lo(9)) << 43) | (l1 >> 21);
69 	irec->br_blockcount = l1 & xfs_mask64lo(21);
70 	if (l0 >> (64 - BMBT_EXNTFLAG_BITLEN))
71 		irec->br_state = XFS_EXT_UNWRITTEN;
72 	else
73 		irec->br_state = XFS_EXT_NORM;
74 }
75 
76 /*
77  * Extract the blockcount field from an on disk bmap extent record.
78  */
79 xfs_filblks_t
80 xfs_bmbt_disk_get_blockcount(
81 	xfs_bmbt_rec_t	*r)
82 {
83 	return (xfs_filblks_t)(be64_to_cpu(r->l1) & xfs_mask64lo(21));
84 }
85 
86 /*
87  * Extract the startoff field from a disk format bmap extent record.
88  */
89 xfs_fileoff_t
90 xfs_bmbt_disk_get_startoff(
91 	xfs_bmbt_rec_t	*r)
92 {
93 	return ((xfs_fileoff_t)be64_to_cpu(r->l0) &
94 		 xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
95 }
96 
97 /*
98  * Set all the fields in a bmap extent record from the uncompressed form.
99  */
100 void
101 xfs_bmbt_disk_set_all(
102 	struct xfs_bmbt_rec	*r,
103 	struct xfs_bmbt_irec	*s)
104 {
105 	int			extent_flag = (s->br_state != XFS_EXT_NORM);
106 
107 	ASSERT(s->br_state == XFS_EXT_NORM || s->br_state == XFS_EXT_UNWRITTEN);
108 	ASSERT(!(s->br_startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)));
109 	ASSERT(!(s->br_blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)));
110 	ASSERT(!(s->br_startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)));
111 
112 	put_unaligned_be64(
113 		((xfs_bmbt_rec_base_t)extent_flag << 63) |
114 		 ((xfs_bmbt_rec_base_t)s->br_startoff << 9) |
115 		 ((xfs_bmbt_rec_base_t)s->br_startblock >> 43), &r->l0);
116 	put_unaligned_be64(
117 		((xfs_bmbt_rec_base_t)s->br_startblock << 21) |
118 		 ((xfs_bmbt_rec_base_t)s->br_blockcount &
119 		  (xfs_bmbt_rec_base_t)xfs_mask64lo(21)), &r->l1);
120 }
121 
122 /*
123  * Convert in-memory form of btree root to on-disk form.
124  */
125 void
126 xfs_bmbt_to_bmdr(
127 	struct xfs_mount	*mp,
128 	struct xfs_btree_block	*rblock,
129 	int			rblocklen,
130 	xfs_bmdr_block_t	*dblock,
131 	int			dblocklen)
132 {
133 	int			dmxr;
134 	xfs_bmbt_key_t		*fkp;
135 	__be64			*fpp;
136 	xfs_bmbt_key_t		*tkp;
137 	__be64			*tpp;
138 
139 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
140 		ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_CRC_MAGIC));
141 		ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid,
142 		       &mp->m_sb.sb_meta_uuid));
143 		ASSERT(rblock->bb_u.l.bb_blkno ==
144 		       cpu_to_be64(XFS_BUF_DADDR_NULL));
145 	} else
146 		ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_MAGIC));
147 	ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
148 	ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
149 	ASSERT(rblock->bb_level != 0);
150 	dblock->bb_level = rblock->bb_level;
151 	dblock->bb_numrecs = rblock->bb_numrecs;
152 	dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
153 	fkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
154 	tkp = XFS_BMDR_KEY_ADDR(dblock, 1);
155 	fpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
156 	tpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
157 	dmxr = be16_to_cpu(dblock->bb_numrecs);
158 	memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
159 	memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
160 }
161 
162 STATIC struct xfs_btree_cur *
163 xfs_bmbt_dup_cursor(
164 	struct xfs_btree_cur	*cur)
165 {
166 	struct xfs_btree_cur	*new;
167 
168 	new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
169 			cur->bc_ino.ip, cur->bc_ino.whichfork);
170 
171 	/*
172 	 * Copy the firstblock, dfops, and flags values,
173 	 * since init cursor doesn't get them.
174 	 */
175 	new->bc_ino.flags = cur->bc_ino.flags;
176 
177 	return new;
178 }
179 
180 STATIC void
181 xfs_bmbt_update_cursor(
182 	struct xfs_btree_cur	*src,
183 	struct xfs_btree_cur	*dst)
184 {
185 	ASSERT((dst->bc_tp->t_firstblock != NULLFSBLOCK) ||
186 	       (dst->bc_ino.ip->i_d.di_flags & XFS_DIFLAG_REALTIME));
187 
188 	dst->bc_ino.allocated += src->bc_ino.allocated;
189 	dst->bc_tp->t_firstblock = src->bc_tp->t_firstblock;
190 
191 	src->bc_ino.allocated = 0;
192 }
193 
194 STATIC int
195 xfs_bmbt_alloc_block(
196 	struct xfs_btree_cur	*cur,
197 	union xfs_btree_ptr	*start,
198 	union xfs_btree_ptr	*new,
199 	int			*stat)
200 {
201 	xfs_alloc_arg_t		args;		/* block allocation args */
202 	int			error;		/* error return value */
203 
204 	memset(&args, 0, sizeof(args));
205 	args.tp = cur->bc_tp;
206 	args.mp = cur->bc_mp;
207 	args.fsbno = cur->bc_tp->t_firstblock;
208 	xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_ino.ip->i_ino,
209 			cur->bc_ino.whichfork);
210 
211 	if (args.fsbno == NULLFSBLOCK) {
212 		args.fsbno = be64_to_cpu(start->l);
213 		args.type = XFS_ALLOCTYPE_START_BNO;
214 		/*
215 		 * Make sure there is sufficient room left in the AG to
216 		 * complete a full tree split for an extent insert.  If
217 		 * we are converting the middle part of an extent then
218 		 * we may need space for two tree splits.
219 		 *
220 		 * We are relying on the caller to make the correct block
221 		 * reservation for this operation to succeed.  If the
222 		 * reservation amount is insufficient then we may fail a
223 		 * block allocation here and corrupt the filesystem.
224 		 */
225 		args.minleft = args.tp->t_blk_res;
226 	} else if (cur->bc_tp->t_flags & XFS_TRANS_LOWMODE) {
227 		args.type = XFS_ALLOCTYPE_START_BNO;
228 	} else {
229 		args.type = XFS_ALLOCTYPE_NEAR_BNO;
230 	}
231 
232 	args.minlen = args.maxlen = args.prod = 1;
233 	args.wasdel = cur->bc_ino.flags & XFS_BTCUR_BMBT_WASDEL;
234 	if (!args.wasdel && args.tp->t_blk_res == 0) {
235 		error = -ENOSPC;
236 		goto error0;
237 	}
238 	error = xfs_alloc_vextent(&args);
239 	if (error)
240 		goto error0;
241 
242 	if (args.fsbno == NULLFSBLOCK && args.minleft) {
243 		/*
244 		 * Could not find an AG with enough free space to satisfy
245 		 * a full btree split.  Try again and if
246 		 * successful activate the lowspace algorithm.
247 		 */
248 		args.fsbno = 0;
249 		args.type = XFS_ALLOCTYPE_FIRST_AG;
250 		error = xfs_alloc_vextent(&args);
251 		if (error)
252 			goto error0;
253 		cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
254 	}
255 	if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
256 		*stat = 0;
257 		return 0;
258 	}
259 
260 	ASSERT(args.len == 1);
261 	cur->bc_tp->t_firstblock = args.fsbno;
262 	cur->bc_ino.allocated++;
263 	cur->bc_ino.ip->i_d.di_nblocks++;
264 	xfs_trans_log_inode(args.tp, cur->bc_ino.ip, XFS_ILOG_CORE);
265 	xfs_trans_mod_dquot_byino(args.tp, cur->bc_ino.ip,
266 			XFS_TRANS_DQ_BCOUNT, 1L);
267 
268 	new->l = cpu_to_be64(args.fsbno);
269 
270 	*stat = 1;
271 	return 0;
272 
273  error0:
274 	return error;
275 }
276 
277 STATIC int
278 xfs_bmbt_free_block(
279 	struct xfs_btree_cur	*cur,
280 	struct xfs_buf		*bp)
281 {
282 	struct xfs_mount	*mp = cur->bc_mp;
283 	struct xfs_inode	*ip = cur->bc_ino.ip;
284 	struct xfs_trans	*tp = cur->bc_tp;
285 	xfs_fsblock_t		fsbno = XFS_DADDR_TO_FSB(mp, XFS_BUF_ADDR(bp));
286 	struct xfs_owner_info	oinfo;
287 
288 	xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_ino.whichfork);
289 	xfs_bmap_add_free(cur->bc_tp, fsbno, 1, &oinfo);
290 	ip->i_d.di_nblocks--;
291 
292 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
293 	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
294 	return 0;
295 }
296 
297 STATIC int
298 xfs_bmbt_get_minrecs(
299 	struct xfs_btree_cur	*cur,
300 	int			level)
301 {
302 	if (level == cur->bc_nlevels - 1) {
303 		struct xfs_ifork	*ifp;
304 
305 		ifp = XFS_IFORK_PTR(cur->bc_ino.ip,
306 				    cur->bc_ino.whichfork);
307 
308 		return xfs_bmbt_maxrecs(cur->bc_mp,
309 					ifp->if_broot_bytes, level == 0) / 2;
310 	}
311 
312 	return cur->bc_mp->m_bmap_dmnr[level != 0];
313 }
314 
315 int
316 xfs_bmbt_get_maxrecs(
317 	struct xfs_btree_cur	*cur,
318 	int			level)
319 {
320 	if (level == cur->bc_nlevels - 1) {
321 		struct xfs_ifork	*ifp;
322 
323 		ifp = XFS_IFORK_PTR(cur->bc_ino.ip,
324 				    cur->bc_ino.whichfork);
325 
326 		return xfs_bmbt_maxrecs(cur->bc_mp,
327 					ifp->if_broot_bytes, level == 0);
328 	}
329 
330 	return cur->bc_mp->m_bmap_dmxr[level != 0];
331 
332 }
333 
334 /*
335  * Get the maximum records we could store in the on-disk format.
336  *
337  * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
338  * for the root node this checks the available space in the dinode fork
339  * so that we can resize the in-memory buffer to match it.  After a
340  * resize to the maximum size this function returns the same value
341  * as xfs_bmbt_get_maxrecs for the root node, too.
342  */
343 STATIC int
344 xfs_bmbt_get_dmaxrecs(
345 	struct xfs_btree_cur	*cur,
346 	int			level)
347 {
348 	if (level != cur->bc_nlevels - 1)
349 		return cur->bc_mp->m_bmap_dmxr[level != 0];
350 	return xfs_bmdr_maxrecs(cur->bc_ino.forksize, level == 0);
351 }
352 
353 STATIC void
354 xfs_bmbt_init_key_from_rec(
355 	union xfs_btree_key	*key,
356 	union xfs_btree_rec	*rec)
357 {
358 	key->bmbt.br_startoff =
359 		cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
360 }
361 
362 STATIC void
363 xfs_bmbt_init_high_key_from_rec(
364 	union xfs_btree_key	*key,
365 	union xfs_btree_rec	*rec)
366 {
367 	key->bmbt.br_startoff = cpu_to_be64(
368 			xfs_bmbt_disk_get_startoff(&rec->bmbt) +
369 			xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
370 }
371 
372 STATIC void
373 xfs_bmbt_init_rec_from_cur(
374 	struct xfs_btree_cur	*cur,
375 	union xfs_btree_rec	*rec)
376 {
377 	xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
378 }
379 
380 STATIC void
381 xfs_bmbt_init_ptr_from_cur(
382 	struct xfs_btree_cur	*cur,
383 	union xfs_btree_ptr	*ptr)
384 {
385 	ptr->l = 0;
386 }
387 
388 STATIC int64_t
389 xfs_bmbt_key_diff(
390 	struct xfs_btree_cur	*cur,
391 	union xfs_btree_key	*key)
392 {
393 	return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
394 				      cur->bc_rec.b.br_startoff;
395 }
396 
397 STATIC int64_t
398 xfs_bmbt_diff_two_keys(
399 	struct xfs_btree_cur	*cur,
400 	union xfs_btree_key	*k1,
401 	union xfs_btree_key	*k2)
402 {
403 	uint64_t		a = be64_to_cpu(k1->bmbt.br_startoff);
404 	uint64_t		b = be64_to_cpu(k2->bmbt.br_startoff);
405 
406 	/*
407 	 * Note: This routine previously casted a and b to int64 and subtracted
408 	 * them to generate a result.  This lead to problems if b was the
409 	 * "maximum" key value (all ones) being signed incorrectly, hence this
410 	 * somewhat less efficient version.
411 	 */
412 	if (a > b)
413 		return 1;
414 	if (b > a)
415 		return -1;
416 	return 0;
417 }
418 
419 static xfs_failaddr_t
420 xfs_bmbt_verify(
421 	struct xfs_buf		*bp)
422 {
423 	struct xfs_mount	*mp = bp->b_mount;
424 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
425 	xfs_failaddr_t		fa;
426 	unsigned int		level;
427 
428 	if (!xfs_verify_magic(bp, block->bb_magic))
429 		return __this_address;
430 
431 	if (xfs_sb_version_hascrc(&mp->m_sb)) {
432 		/*
433 		 * XXX: need a better way of verifying the owner here. Right now
434 		 * just make sure there has been one set.
435 		 */
436 		fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
437 		if (fa)
438 			return fa;
439 	}
440 
441 	/*
442 	 * numrecs and level verification.
443 	 *
444 	 * We don't know what fork we belong to, so just verify that the level
445 	 * is less than the maximum of the two. Later checks will be more
446 	 * precise.
447 	 */
448 	level = be16_to_cpu(block->bb_level);
449 	if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
450 		return __this_address;
451 
452 	return xfs_btree_lblock_verify(bp, mp->m_bmap_dmxr[level != 0]);
453 }
454 
455 static void
456 xfs_bmbt_read_verify(
457 	struct xfs_buf	*bp)
458 {
459 	xfs_failaddr_t	fa;
460 
461 	if (!xfs_btree_lblock_verify_crc(bp))
462 		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
463 	else {
464 		fa = xfs_bmbt_verify(bp);
465 		if (fa)
466 			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
467 	}
468 
469 	if (bp->b_error)
470 		trace_xfs_btree_corrupt(bp, _RET_IP_);
471 }
472 
473 static void
474 xfs_bmbt_write_verify(
475 	struct xfs_buf	*bp)
476 {
477 	xfs_failaddr_t	fa;
478 
479 	fa = xfs_bmbt_verify(bp);
480 	if (fa) {
481 		trace_xfs_btree_corrupt(bp, _RET_IP_);
482 		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
483 		return;
484 	}
485 	xfs_btree_lblock_calc_crc(bp);
486 }
487 
488 const struct xfs_buf_ops xfs_bmbt_buf_ops = {
489 	.name = "xfs_bmbt",
490 	.magic = { cpu_to_be32(XFS_BMAP_MAGIC),
491 		   cpu_to_be32(XFS_BMAP_CRC_MAGIC) },
492 	.verify_read = xfs_bmbt_read_verify,
493 	.verify_write = xfs_bmbt_write_verify,
494 	.verify_struct = xfs_bmbt_verify,
495 };
496 
497 
498 STATIC int
499 xfs_bmbt_keys_inorder(
500 	struct xfs_btree_cur	*cur,
501 	union xfs_btree_key	*k1,
502 	union xfs_btree_key	*k2)
503 {
504 	return be64_to_cpu(k1->bmbt.br_startoff) <
505 		be64_to_cpu(k2->bmbt.br_startoff);
506 }
507 
508 STATIC int
509 xfs_bmbt_recs_inorder(
510 	struct xfs_btree_cur	*cur,
511 	union xfs_btree_rec	*r1,
512 	union xfs_btree_rec	*r2)
513 {
514 	return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
515 		xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
516 		xfs_bmbt_disk_get_startoff(&r2->bmbt);
517 }
518 
519 static const struct xfs_btree_ops xfs_bmbt_ops = {
520 	.rec_len		= sizeof(xfs_bmbt_rec_t),
521 	.key_len		= sizeof(xfs_bmbt_key_t),
522 
523 	.dup_cursor		= xfs_bmbt_dup_cursor,
524 	.update_cursor		= xfs_bmbt_update_cursor,
525 	.alloc_block		= xfs_bmbt_alloc_block,
526 	.free_block		= xfs_bmbt_free_block,
527 	.get_maxrecs		= xfs_bmbt_get_maxrecs,
528 	.get_minrecs		= xfs_bmbt_get_minrecs,
529 	.get_dmaxrecs		= xfs_bmbt_get_dmaxrecs,
530 	.init_key_from_rec	= xfs_bmbt_init_key_from_rec,
531 	.init_high_key_from_rec	= xfs_bmbt_init_high_key_from_rec,
532 	.init_rec_from_cur	= xfs_bmbt_init_rec_from_cur,
533 	.init_ptr_from_cur	= xfs_bmbt_init_ptr_from_cur,
534 	.key_diff		= xfs_bmbt_key_diff,
535 	.diff_two_keys		= xfs_bmbt_diff_two_keys,
536 	.buf_ops		= &xfs_bmbt_buf_ops,
537 	.keys_inorder		= xfs_bmbt_keys_inorder,
538 	.recs_inorder		= xfs_bmbt_recs_inorder,
539 };
540 
541 /*
542  * Allocate a new bmap btree cursor.
543  */
544 struct xfs_btree_cur *				/* new bmap btree cursor */
545 xfs_bmbt_init_cursor(
546 	struct xfs_mount	*mp,		/* file system mount point */
547 	struct xfs_trans	*tp,		/* transaction pointer */
548 	struct xfs_inode	*ip,		/* inode owning the btree */
549 	int			whichfork)	/* data or attr fork */
550 {
551 	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
552 	struct xfs_btree_cur	*cur;
553 	ASSERT(whichfork != XFS_COW_FORK);
554 
555 	cur = kmem_cache_zalloc(xfs_btree_cur_zone, GFP_NOFS | __GFP_NOFAIL);
556 
557 	cur->bc_tp = tp;
558 	cur->bc_mp = mp;
559 	cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
560 	cur->bc_btnum = XFS_BTNUM_BMAP;
561 	cur->bc_blocklog = mp->m_sb.sb_blocklog;
562 	cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_bmbt_2);
563 
564 	cur->bc_ops = &xfs_bmbt_ops;
565 	cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
566 	if (xfs_sb_version_hascrc(&mp->m_sb))
567 		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
568 
569 	cur->bc_ino.forksize = XFS_IFORK_SIZE(ip, whichfork);
570 	cur->bc_ino.ip = ip;
571 	cur->bc_ino.allocated = 0;
572 	cur->bc_ino.flags = 0;
573 	cur->bc_ino.whichfork = whichfork;
574 
575 	return cur;
576 }
577 
578 /*
579  * Calculate number of records in a bmap btree block.
580  */
581 int
582 xfs_bmbt_maxrecs(
583 	struct xfs_mount	*mp,
584 	int			blocklen,
585 	int			leaf)
586 {
587 	blocklen -= XFS_BMBT_BLOCK_LEN(mp);
588 
589 	if (leaf)
590 		return blocklen / sizeof(xfs_bmbt_rec_t);
591 	return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
592 }
593 
594 /*
595  * Calculate number of records in a bmap btree inode root.
596  */
597 int
598 xfs_bmdr_maxrecs(
599 	int			blocklen,
600 	int			leaf)
601 {
602 	blocklen -= sizeof(xfs_bmdr_block_t);
603 
604 	if (leaf)
605 		return blocklen / sizeof(xfs_bmdr_rec_t);
606 	return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
607 }
608 
609 /*
610  * Change the owner of a btree format fork fo the inode passed in. Change it to
611  * the owner of that is passed in so that we can change owners before or after
612  * we switch forks between inodes. The operation that the caller is doing will
613  * determine whether is needs to change owner before or after the switch.
614  *
615  * For demand paged transactional modification, the fork switch should be done
616  * after reading in all the blocks, modifying them and pinning them in the
617  * transaction. For modification when the buffers are already pinned in memory,
618  * the fork switch can be done before changing the owner as we won't need to
619  * validate the owner until the btree buffers are unpinned and writes can occur
620  * again.
621  *
622  * For recovery based ownership change, there is no transactional context and
623  * so a buffer list must be supplied so that we can record the buffers that we
624  * modified for the caller to issue IO on.
625  */
626 int
627 xfs_bmbt_change_owner(
628 	struct xfs_trans	*tp,
629 	struct xfs_inode	*ip,
630 	int			whichfork,
631 	xfs_ino_t		new_owner,
632 	struct list_head	*buffer_list)
633 {
634 	struct xfs_btree_cur	*cur;
635 	int			error;
636 
637 	ASSERT(tp || buffer_list);
638 	ASSERT(!(tp && buffer_list));
639 	ASSERT(XFS_IFORK_PTR(ip, whichfork)->if_format == XFS_DINODE_FMT_BTREE);
640 
641 	cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
642 	cur->bc_ino.flags |= XFS_BTCUR_BMBT_INVALID_OWNER;
643 
644 	error = xfs_btree_change_owner(cur, new_owner, buffer_list);
645 	xfs_btree_del_cursor(cur, error);
646 	return error;
647 }
648 
649 /* Calculate the bmap btree size for some records. */
650 unsigned long long
651 xfs_bmbt_calc_size(
652 	struct xfs_mount	*mp,
653 	unsigned long long	len)
654 {
655 	return xfs_btree_calc_size(mp->m_bmap_dmnr, len);
656 }
657