xref: /openbmc/linux/fs/xfs/libxfs/xfs_bmap_btree.c (revision 96de2506)
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.flags = cur->bc_private.b.flags;
179 
180 	return new;
181 }
182 
183 STATIC void
184 xfs_bmbt_update_cursor(
185 	struct xfs_btree_cur	*src,
186 	struct xfs_btree_cur	*dst)
187 {
188 	ASSERT((dst->bc_tp->t_firstblock != NULLFSBLOCK) ||
189 	       (dst->bc_private.b.ip->i_d.di_flags & XFS_DIFLAG_REALTIME));
190 
191 	dst->bc_private.b.allocated += src->bc_private.b.allocated;
192 	dst->bc_tp->t_firstblock = src->bc_tp->t_firstblock;
193 
194 	src->bc_private.b.allocated = 0;
195 }
196 
197 STATIC int
198 xfs_bmbt_alloc_block(
199 	struct xfs_btree_cur	*cur,
200 	union xfs_btree_ptr	*start,
201 	union xfs_btree_ptr	*new,
202 	int			*stat)
203 {
204 	xfs_alloc_arg_t		args;		/* block allocation args */
205 	int			error;		/* error return value */
206 
207 	memset(&args, 0, sizeof(args));
208 	args.tp = cur->bc_tp;
209 	args.mp = cur->bc_mp;
210 	args.fsbno = cur->bc_tp->t_firstblock;
211 	xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_private.b.ip->i_ino,
212 			cur->bc_private.b.whichfork);
213 
214 	if (args.fsbno == NULLFSBLOCK) {
215 		args.fsbno = be64_to_cpu(start->l);
216 		args.type = XFS_ALLOCTYPE_START_BNO;
217 		/*
218 		 * Make sure there is sufficient room left in the AG to
219 		 * complete a full tree split for an extent insert.  If
220 		 * we are converting the middle part of an extent then
221 		 * we may need space for two tree splits.
222 		 *
223 		 * We are relying on the caller to make the correct block
224 		 * reservation for this operation to succeed.  If the
225 		 * reservation amount is insufficient then we may fail a
226 		 * block allocation here and corrupt the filesystem.
227 		 */
228 		args.minleft = args.tp->t_blk_res;
229 	} else if (cur->bc_tp->t_flags & XFS_TRANS_LOWMODE) {
230 		args.type = XFS_ALLOCTYPE_START_BNO;
231 	} else {
232 		args.type = XFS_ALLOCTYPE_NEAR_BNO;
233 	}
234 
235 	args.minlen = args.maxlen = args.prod = 1;
236 	args.wasdel = cur->bc_private.b.flags & XFS_BTCUR_BPRV_WASDEL;
237 	if (!args.wasdel && args.tp->t_blk_res == 0) {
238 		error = -ENOSPC;
239 		goto error0;
240 	}
241 	error = xfs_alloc_vextent(&args);
242 	if (error)
243 		goto error0;
244 
245 	if (args.fsbno == NULLFSBLOCK && args.minleft) {
246 		/*
247 		 * Could not find an AG with enough free space to satisfy
248 		 * a full btree split.  Try again and if
249 		 * successful activate the lowspace algorithm.
250 		 */
251 		args.fsbno = 0;
252 		args.type = XFS_ALLOCTYPE_FIRST_AG;
253 		error = xfs_alloc_vextent(&args);
254 		if (error)
255 			goto error0;
256 		cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
257 	}
258 	if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
259 		*stat = 0;
260 		return 0;
261 	}
262 
263 	ASSERT(args.len == 1);
264 	cur->bc_tp->t_firstblock = args.fsbno;
265 	cur->bc_private.b.allocated++;
266 	cur->bc_private.b.ip->i_d.di_nblocks++;
267 	xfs_trans_log_inode(args.tp, cur->bc_private.b.ip, XFS_ILOG_CORE);
268 	xfs_trans_mod_dquot_byino(args.tp, cur->bc_private.b.ip,
269 			XFS_TRANS_DQ_BCOUNT, 1L);
270 
271 	new->l = cpu_to_be64(args.fsbno);
272 
273 	*stat = 1;
274 	return 0;
275 
276  error0:
277 	return error;
278 }
279 
280 STATIC int
281 xfs_bmbt_free_block(
282 	struct xfs_btree_cur	*cur,
283 	struct xfs_buf		*bp)
284 {
285 	struct xfs_mount	*mp = cur->bc_mp;
286 	struct xfs_inode	*ip = cur->bc_private.b.ip;
287 	struct xfs_trans	*tp = cur->bc_tp;
288 	xfs_fsblock_t		fsbno = XFS_DADDR_TO_FSB(mp, XFS_BUF_ADDR(bp));
289 	struct xfs_owner_info	oinfo;
290 
291 	xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_private.b.whichfork);
292 	xfs_bmap_add_free(cur->bc_tp, fsbno, 1, &oinfo);
293 	ip->i_d.di_nblocks--;
294 
295 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
296 	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
297 	return 0;
298 }
299 
300 STATIC int
301 xfs_bmbt_get_minrecs(
302 	struct xfs_btree_cur	*cur,
303 	int			level)
304 {
305 	if (level == cur->bc_nlevels - 1) {
306 		struct xfs_ifork	*ifp;
307 
308 		ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
309 				    cur->bc_private.b.whichfork);
310 
311 		return xfs_bmbt_maxrecs(cur->bc_mp,
312 					ifp->if_broot_bytes, level == 0) / 2;
313 	}
314 
315 	return cur->bc_mp->m_bmap_dmnr[level != 0];
316 }
317 
318 int
319 xfs_bmbt_get_maxrecs(
320 	struct xfs_btree_cur	*cur,
321 	int			level)
322 {
323 	if (level == cur->bc_nlevels - 1) {
324 		struct xfs_ifork	*ifp;
325 
326 		ifp = XFS_IFORK_PTR(cur->bc_private.b.ip,
327 				    cur->bc_private.b.whichfork);
328 
329 		return xfs_bmbt_maxrecs(cur->bc_mp,
330 					ifp->if_broot_bytes, level == 0);
331 	}
332 
333 	return cur->bc_mp->m_bmap_dmxr[level != 0];
334 
335 }
336 
337 /*
338  * Get the maximum records we could store in the on-disk format.
339  *
340  * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
341  * for the root node this checks the available space in the dinode fork
342  * so that we can resize the in-memory buffer to match it.  After a
343  * resize to the maximum size this function returns the same value
344  * as xfs_bmbt_get_maxrecs for the root node, too.
345  */
346 STATIC int
347 xfs_bmbt_get_dmaxrecs(
348 	struct xfs_btree_cur	*cur,
349 	int			level)
350 {
351 	if (level != cur->bc_nlevels - 1)
352 		return cur->bc_mp->m_bmap_dmxr[level != 0];
353 	return xfs_bmdr_maxrecs(cur->bc_private.b.forksize, level == 0);
354 }
355 
356 STATIC void
357 xfs_bmbt_init_key_from_rec(
358 	union xfs_btree_key	*key,
359 	union xfs_btree_rec	*rec)
360 {
361 	key->bmbt.br_startoff =
362 		cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
363 }
364 
365 STATIC void
366 xfs_bmbt_init_high_key_from_rec(
367 	union xfs_btree_key	*key,
368 	union xfs_btree_rec	*rec)
369 {
370 	key->bmbt.br_startoff = cpu_to_be64(
371 			xfs_bmbt_disk_get_startoff(&rec->bmbt) +
372 			xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
373 }
374 
375 STATIC void
376 xfs_bmbt_init_rec_from_cur(
377 	struct xfs_btree_cur	*cur,
378 	union xfs_btree_rec	*rec)
379 {
380 	xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
381 }
382 
383 STATIC void
384 xfs_bmbt_init_ptr_from_cur(
385 	struct xfs_btree_cur	*cur,
386 	union xfs_btree_ptr	*ptr)
387 {
388 	ptr->l = 0;
389 }
390 
391 STATIC int64_t
392 xfs_bmbt_key_diff(
393 	struct xfs_btree_cur	*cur,
394 	union xfs_btree_key	*key)
395 {
396 	return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
397 				      cur->bc_rec.b.br_startoff;
398 }
399 
400 STATIC int64_t
401 xfs_bmbt_diff_two_keys(
402 	struct xfs_btree_cur	*cur,
403 	union xfs_btree_key	*k1,
404 	union xfs_btree_key	*k2)
405 {
406 	return (int64_t)be64_to_cpu(k1->bmbt.br_startoff) -
407 			  be64_to_cpu(k2->bmbt.br_startoff);
408 }
409 
410 static xfs_failaddr_t
411 xfs_bmbt_verify(
412 	struct xfs_buf		*bp)
413 {
414 	struct xfs_mount	*mp = bp->b_target->bt_mount;
415 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
416 	xfs_failaddr_t		fa;
417 	unsigned int		level;
418 
419 	switch (block->bb_magic) {
420 	case cpu_to_be32(XFS_BMAP_CRC_MAGIC):
421 		/*
422 		 * XXX: need a better way of verifying the owner here. Right now
423 		 * just make sure there has been one set.
424 		 */
425 		fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
426 		if (fa)
427 			return fa;
428 		/* fall through */
429 	case cpu_to_be32(XFS_BMAP_MAGIC):
430 		break;
431 	default:
432 		return __this_address;
433 	}
434 
435 	/*
436 	 * numrecs and level verification.
437 	 *
438 	 * We don't know what fork we belong to, so just verify that the level
439 	 * is less than the maximum of the two. Later checks will be more
440 	 * precise.
441 	 */
442 	level = be16_to_cpu(block->bb_level);
443 	if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
444 		return __this_address;
445 
446 	return xfs_btree_lblock_verify(bp, mp->m_bmap_dmxr[level != 0]);
447 }
448 
449 static void
450 xfs_bmbt_read_verify(
451 	struct xfs_buf	*bp)
452 {
453 	xfs_failaddr_t	fa;
454 
455 	if (!xfs_btree_lblock_verify_crc(bp))
456 		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
457 	else {
458 		fa = xfs_bmbt_verify(bp);
459 		if (fa)
460 			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
461 	}
462 
463 	if (bp->b_error)
464 		trace_xfs_btree_corrupt(bp, _RET_IP_);
465 }
466 
467 static void
468 xfs_bmbt_write_verify(
469 	struct xfs_buf	*bp)
470 {
471 	xfs_failaddr_t	fa;
472 
473 	fa = xfs_bmbt_verify(bp);
474 	if (fa) {
475 		trace_xfs_btree_corrupt(bp, _RET_IP_);
476 		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
477 		return;
478 	}
479 	xfs_btree_lblock_calc_crc(bp);
480 }
481 
482 const struct xfs_buf_ops xfs_bmbt_buf_ops = {
483 	.name = "xfs_bmbt",
484 	.verify_read = xfs_bmbt_read_verify,
485 	.verify_write = xfs_bmbt_write_verify,
486 	.verify_struct = xfs_bmbt_verify,
487 };
488 
489 
490 STATIC int
491 xfs_bmbt_keys_inorder(
492 	struct xfs_btree_cur	*cur,
493 	union xfs_btree_key	*k1,
494 	union xfs_btree_key	*k2)
495 {
496 	return be64_to_cpu(k1->bmbt.br_startoff) <
497 		be64_to_cpu(k2->bmbt.br_startoff);
498 }
499 
500 STATIC int
501 xfs_bmbt_recs_inorder(
502 	struct xfs_btree_cur	*cur,
503 	union xfs_btree_rec	*r1,
504 	union xfs_btree_rec	*r2)
505 {
506 	return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
507 		xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
508 		xfs_bmbt_disk_get_startoff(&r2->bmbt);
509 }
510 
511 static const struct xfs_btree_ops xfs_bmbt_ops = {
512 	.rec_len		= sizeof(xfs_bmbt_rec_t),
513 	.key_len		= sizeof(xfs_bmbt_key_t),
514 
515 	.dup_cursor		= xfs_bmbt_dup_cursor,
516 	.update_cursor		= xfs_bmbt_update_cursor,
517 	.alloc_block		= xfs_bmbt_alloc_block,
518 	.free_block		= xfs_bmbt_free_block,
519 	.get_maxrecs		= xfs_bmbt_get_maxrecs,
520 	.get_minrecs		= xfs_bmbt_get_minrecs,
521 	.get_dmaxrecs		= xfs_bmbt_get_dmaxrecs,
522 	.init_key_from_rec	= xfs_bmbt_init_key_from_rec,
523 	.init_high_key_from_rec	= xfs_bmbt_init_high_key_from_rec,
524 	.init_rec_from_cur	= xfs_bmbt_init_rec_from_cur,
525 	.init_ptr_from_cur	= xfs_bmbt_init_ptr_from_cur,
526 	.key_diff		= xfs_bmbt_key_diff,
527 	.diff_two_keys		= xfs_bmbt_diff_two_keys,
528 	.buf_ops		= &xfs_bmbt_buf_ops,
529 	.keys_inorder		= xfs_bmbt_keys_inorder,
530 	.recs_inorder		= xfs_bmbt_recs_inorder,
531 };
532 
533 /*
534  * Allocate a new bmap btree cursor.
535  */
536 struct xfs_btree_cur *				/* new bmap btree cursor */
537 xfs_bmbt_init_cursor(
538 	struct xfs_mount	*mp,		/* file system mount point */
539 	struct xfs_trans	*tp,		/* transaction pointer */
540 	struct xfs_inode	*ip,		/* inode owning the btree */
541 	int			whichfork)	/* data or attr fork */
542 {
543 	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
544 	struct xfs_btree_cur	*cur;
545 	ASSERT(whichfork != XFS_COW_FORK);
546 
547 	cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
548 
549 	cur->bc_tp = tp;
550 	cur->bc_mp = mp;
551 	cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
552 	cur->bc_btnum = XFS_BTNUM_BMAP;
553 	cur->bc_blocklog = mp->m_sb.sb_blocklog;
554 	cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_bmbt_2);
555 
556 	cur->bc_ops = &xfs_bmbt_ops;
557 	cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
558 	if (xfs_sb_version_hascrc(&mp->m_sb))
559 		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
560 
561 	cur->bc_private.b.forksize = XFS_IFORK_SIZE(ip, whichfork);
562 	cur->bc_private.b.ip = ip;
563 	cur->bc_private.b.allocated = 0;
564 	cur->bc_private.b.flags = 0;
565 	cur->bc_private.b.whichfork = whichfork;
566 
567 	return cur;
568 }
569 
570 /*
571  * Calculate number of records in a bmap btree block.
572  */
573 int
574 xfs_bmbt_maxrecs(
575 	struct xfs_mount	*mp,
576 	int			blocklen,
577 	int			leaf)
578 {
579 	blocklen -= XFS_BMBT_BLOCK_LEN(mp);
580 
581 	if (leaf)
582 		return blocklen / sizeof(xfs_bmbt_rec_t);
583 	return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
584 }
585 
586 /*
587  * Calculate number of records in a bmap btree inode root.
588  */
589 int
590 xfs_bmdr_maxrecs(
591 	int			blocklen,
592 	int			leaf)
593 {
594 	blocklen -= sizeof(xfs_bmdr_block_t);
595 
596 	if (leaf)
597 		return blocklen / sizeof(xfs_bmdr_rec_t);
598 	return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
599 }
600 
601 /*
602  * Change the owner of a btree format fork fo the inode passed in. Change it to
603  * the owner of that is passed in so that we can change owners before or after
604  * we switch forks between inodes. The operation that the caller is doing will
605  * determine whether is needs to change owner before or after the switch.
606  *
607  * For demand paged transactional modification, the fork switch should be done
608  * after reading in all the blocks, modifying them and pinning them in the
609  * transaction. For modification when the buffers are already pinned in memory,
610  * the fork switch can be done before changing the owner as we won't need to
611  * validate the owner until the btree buffers are unpinned and writes can occur
612  * again.
613  *
614  * For recovery based ownership change, there is no transactional context and
615  * so a buffer list must be supplied so that we can record the buffers that we
616  * modified for the caller to issue IO on.
617  */
618 int
619 xfs_bmbt_change_owner(
620 	struct xfs_trans	*tp,
621 	struct xfs_inode	*ip,
622 	int			whichfork,
623 	xfs_ino_t		new_owner,
624 	struct list_head	*buffer_list)
625 {
626 	struct xfs_btree_cur	*cur;
627 	int			error;
628 
629 	ASSERT(tp || buffer_list);
630 	ASSERT(!(tp && buffer_list));
631 	if (whichfork == XFS_DATA_FORK)
632 		ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_BTREE);
633 	else
634 		ASSERT(ip->i_d.di_aformat == XFS_DINODE_FMT_BTREE);
635 
636 	cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
637 	if (!cur)
638 		return -ENOMEM;
639 	cur->bc_private.b.flags |= XFS_BTCUR_BPRV_INVALID_OWNER;
640 
641 	error = xfs_btree_change_owner(cur, new_owner, buffer_list);
642 	xfs_btree_del_cursor(cur, error);
643 	return error;
644 }
645 
646 /* Calculate the bmap btree size for some records. */
647 unsigned long long
648 xfs_bmbt_calc_size(
649 	struct xfs_mount	*mp,
650 	unsigned long long	len)
651 {
652 	return xfs_btree_calc_size(mp->m_bmap_dmnr, len);
653 }
654