xref: /openbmc/linux/fs/xfs/libxfs/xfs_bmap_btree.c (revision 55eb9a6c)
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 static struct kmem_cache	*xfs_bmbt_cur_cache;
26 
27 /*
28  * Convert on-disk form of btree root to in-memory form.
29  */
30 void
31 xfs_bmdr_to_bmbt(
32 	struct xfs_inode	*ip,
33 	xfs_bmdr_block_t	*dblock,
34 	int			dblocklen,
35 	struct xfs_btree_block	*rblock,
36 	int			rblocklen)
37 {
38 	struct xfs_mount	*mp = ip->i_mount;
39 	int			dmxr;
40 	xfs_bmbt_key_t		*fkp;
41 	__be64			*fpp;
42 	xfs_bmbt_key_t		*tkp;
43 	__be64			*tpp;
44 
45 	xfs_btree_init_block_int(mp, rblock, XFS_BUF_DADDR_NULL,
46 				 XFS_BTNUM_BMAP, 0, 0, ip->i_ino,
47 				 XFS_BTREE_LONG_PTRS);
48 	rblock->bb_level = dblock->bb_level;
49 	ASSERT(be16_to_cpu(rblock->bb_level) > 0);
50 	rblock->bb_numrecs = dblock->bb_numrecs;
51 	dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
52 	fkp = XFS_BMDR_KEY_ADDR(dblock, 1);
53 	tkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
54 	fpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
55 	tpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
56 	dmxr = be16_to_cpu(dblock->bb_numrecs);
57 	memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
58 	memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
59 }
60 
61 void
62 xfs_bmbt_disk_get_all(
63 	const struct xfs_bmbt_rec *rec,
64 	struct xfs_bmbt_irec	*irec)
65 {
66 	uint64_t		l0 = get_unaligned_be64(&rec->l0);
67 	uint64_t		l1 = get_unaligned_be64(&rec->l1);
68 
69 	irec->br_startoff = (l0 & xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
70 	irec->br_startblock = ((l0 & xfs_mask64lo(9)) << 43) | (l1 >> 21);
71 	irec->br_blockcount = l1 & xfs_mask64lo(21);
72 	if (l0 >> (64 - BMBT_EXNTFLAG_BITLEN))
73 		irec->br_state = XFS_EXT_UNWRITTEN;
74 	else
75 		irec->br_state = XFS_EXT_NORM;
76 }
77 
78 /*
79  * Extract the blockcount field from an on disk bmap extent record.
80  */
81 xfs_filblks_t
82 xfs_bmbt_disk_get_blockcount(
83 	const struct xfs_bmbt_rec	*r)
84 {
85 	return (xfs_filblks_t)(be64_to_cpu(r->l1) & xfs_mask64lo(21));
86 }
87 
88 /*
89  * Extract the startoff field from a disk format bmap extent record.
90  */
91 xfs_fileoff_t
92 xfs_bmbt_disk_get_startoff(
93 	const struct xfs_bmbt_rec	*r)
94 {
95 	return ((xfs_fileoff_t)be64_to_cpu(r->l0) &
96 		 xfs_mask64lo(64 - BMBT_EXNTFLAG_BITLEN)) >> 9;
97 }
98 
99 /*
100  * Set all the fields in a bmap extent record from the uncompressed form.
101  */
102 void
103 xfs_bmbt_disk_set_all(
104 	struct xfs_bmbt_rec	*r,
105 	struct xfs_bmbt_irec	*s)
106 {
107 	int			extent_flag = (s->br_state != XFS_EXT_NORM);
108 
109 	ASSERT(s->br_state == XFS_EXT_NORM || s->br_state == XFS_EXT_UNWRITTEN);
110 	ASSERT(!(s->br_startoff & xfs_mask64hi(64-BMBT_STARTOFF_BITLEN)));
111 	ASSERT(!(s->br_blockcount & xfs_mask64hi(64-BMBT_BLOCKCOUNT_BITLEN)));
112 	ASSERT(!(s->br_startblock & xfs_mask64hi(64-BMBT_STARTBLOCK_BITLEN)));
113 
114 	put_unaligned_be64(
115 		((xfs_bmbt_rec_base_t)extent_flag << 63) |
116 		 ((xfs_bmbt_rec_base_t)s->br_startoff << 9) |
117 		 ((xfs_bmbt_rec_base_t)s->br_startblock >> 43), &r->l0);
118 	put_unaligned_be64(
119 		((xfs_bmbt_rec_base_t)s->br_startblock << 21) |
120 		 ((xfs_bmbt_rec_base_t)s->br_blockcount &
121 		  (xfs_bmbt_rec_base_t)xfs_mask64lo(21)), &r->l1);
122 }
123 
124 /*
125  * Convert in-memory form of btree root to on-disk form.
126  */
127 void
128 xfs_bmbt_to_bmdr(
129 	struct xfs_mount	*mp,
130 	struct xfs_btree_block	*rblock,
131 	int			rblocklen,
132 	xfs_bmdr_block_t	*dblock,
133 	int			dblocklen)
134 {
135 	int			dmxr;
136 	xfs_bmbt_key_t		*fkp;
137 	__be64			*fpp;
138 	xfs_bmbt_key_t		*tkp;
139 	__be64			*tpp;
140 
141 	if (xfs_has_crc(mp)) {
142 		ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_CRC_MAGIC));
143 		ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid,
144 		       &mp->m_sb.sb_meta_uuid));
145 		ASSERT(rblock->bb_u.l.bb_blkno ==
146 		       cpu_to_be64(XFS_BUF_DADDR_NULL));
147 	} else
148 		ASSERT(rblock->bb_magic == cpu_to_be32(XFS_BMAP_MAGIC));
149 	ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
150 	ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
151 	ASSERT(rblock->bb_level != 0);
152 	dblock->bb_level = rblock->bb_level;
153 	dblock->bb_numrecs = rblock->bb_numrecs;
154 	dmxr = xfs_bmdr_maxrecs(dblocklen, 0);
155 	fkp = XFS_BMBT_KEY_ADDR(mp, rblock, 1);
156 	tkp = XFS_BMDR_KEY_ADDR(dblock, 1);
157 	fpp = XFS_BMAP_BROOT_PTR_ADDR(mp, rblock, 1, rblocklen);
158 	tpp = XFS_BMDR_PTR_ADDR(dblock, 1, dmxr);
159 	dmxr = be16_to_cpu(dblock->bb_numrecs);
160 	memcpy(tkp, fkp, sizeof(*fkp) * dmxr);
161 	memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
162 }
163 
164 STATIC struct xfs_btree_cur *
165 xfs_bmbt_dup_cursor(
166 	struct xfs_btree_cur	*cur)
167 {
168 	struct xfs_btree_cur	*new;
169 
170 	new = xfs_bmbt_init_cursor(cur->bc_mp, cur->bc_tp,
171 			cur->bc_ino.ip, cur->bc_ino.whichfork);
172 
173 	/*
174 	 * Copy the firstblock, dfops, and flags values,
175 	 * since init cursor doesn't get them.
176 	 */
177 	new->bc_ino.flags = cur->bc_ino.flags;
178 
179 	return new;
180 }
181 
182 STATIC void
183 xfs_bmbt_update_cursor(
184 	struct xfs_btree_cur	*src,
185 	struct xfs_btree_cur	*dst)
186 {
187 	ASSERT((dst->bc_tp->t_firstblock != NULLFSBLOCK) ||
188 	       (dst->bc_ino.ip->i_diflags & XFS_DIFLAG_REALTIME));
189 
190 	dst->bc_ino.allocated += src->bc_ino.allocated;
191 	dst->bc_tp->t_firstblock = src->bc_tp->t_firstblock;
192 
193 	src->bc_ino.allocated = 0;
194 }
195 
196 STATIC int
197 xfs_bmbt_alloc_block(
198 	struct xfs_btree_cur		*cur,
199 	const union xfs_btree_ptr	*start,
200 	union xfs_btree_ptr		*new,
201 	int				*stat)
202 {
203 	xfs_alloc_arg_t		args;		/* block allocation args */
204 	int			error;		/* error return value */
205 
206 	memset(&args, 0, sizeof(args));
207 	args.tp = cur->bc_tp;
208 	args.mp = cur->bc_mp;
209 	args.fsbno = cur->bc_tp->t_firstblock;
210 	xfs_rmap_ino_bmbt_owner(&args.oinfo, cur->bc_ino.ip->i_ino,
211 			cur->bc_ino.whichfork);
212 
213 	if (args.fsbno == NULLFSBLOCK) {
214 		args.fsbno = be64_to_cpu(start->l);
215 		args.type = XFS_ALLOCTYPE_START_BNO;
216 		/*
217 		 * Make sure there is sufficient room left in the AG to
218 		 * complete a full tree split for an extent insert.  If
219 		 * we are converting the middle part of an extent then
220 		 * we may need space for two tree splits.
221 		 *
222 		 * We are relying on the caller to make the correct block
223 		 * reservation for this operation to succeed.  If the
224 		 * reservation amount is insufficient then we may fail a
225 		 * block allocation here and corrupt the filesystem.
226 		 */
227 		args.minleft = args.tp->t_blk_res;
228 	} else if (cur->bc_tp->t_flags & XFS_TRANS_LOWMODE) {
229 		args.type = XFS_ALLOCTYPE_START_BNO;
230 	} else {
231 		args.type = XFS_ALLOCTYPE_NEAR_BNO;
232 	}
233 
234 	args.minlen = args.maxlen = args.prod = 1;
235 	args.wasdel = cur->bc_ino.flags & XFS_BTCUR_BMBT_WASDEL;
236 	if (!args.wasdel && args.tp->t_blk_res == 0) {
237 		error = -ENOSPC;
238 		goto error0;
239 	}
240 	error = xfs_alloc_vextent(&args);
241 	if (error)
242 		goto error0;
243 
244 	if (args.fsbno == NULLFSBLOCK && args.minleft) {
245 		/*
246 		 * Could not find an AG with enough free space to satisfy
247 		 * a full btree split.  Try again and if
248 		 * successful activate the lowspace algorithm.
249 		 */
250 		args.fsbno = 0;
251 		args.type = XFS_ALLOCTYPE_FIRST_AG;
252 		error = xfs_alloc_vextent(&args);
253 		if (error)
254 			goto error0;
255 		cur->bc_tp->t_flags |= XFS_TRANS_LOWMODE;
256 	}
257 	if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
258 		*stat = 0;
259 		return 0;
260 	}
261 
262 	ASSERT(args.len == 1);
263 	cur->bc_tp->t_firstblock = args.fsbno;
264 	cur->bc_ino.allocated++;
265 	cur->bc_ino.ip->i_nblocks++;
266 	xfs_trans_log_inode(args.tp, cur->bc_ino.ip, XFS_ILOG_CORE);
267 	xfs_trans_mod_dquot_byino(args.tp, cur->bc_ino.ip,
268 			XFS_TRANS_DQ_BCOUNT, 1L);
269 
270 	new->l = cpu_to_be64(args.fsbno);
271 
272 	*stat = 1;
273 	return 0;
274 
275  error0:
276 	return error;
277 }
278 
279 STATIC int
280 xfs_bmbt_free_block(
281 	struct xfs_btree_cur	*cur,
282 	struct xfs_buf		*bp)
283 {
284 	struct xfs_mount	*mp = cur->bc_mp;
285 	struct xfs_inode	*ip = cur->bc_ino.ip;
286 	struct xfs_trans	*tp = cur->bc_tp;
287 	xfs_fsblock_t		fsbno = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
288 	struct xfs_owner_info	oinfo;
289 
290 	xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, cur->bc_ino.whichfork);
291 	xfs_free_extent_later(cur->bc_tp, fsbno, 1, &oinfo);
292 	ip->i_nblocks--;
293 
294 	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
295 	xfs_trans_mod_dquot_byino(tp, ip, XFS_TRANS_DQ_BCOUNT, -1L);
296 	return 0;
297 }
298 
299 STATIC int
300 xfs_bmbt_get_minrecs(
301 	struct xfs_btree_cur	*cur,
302 	int			level)
303 {
304 	if (level == cur->bc_nlevels - 1) {
305 		struct xfs_ifork	*ifp;
306 
307 		ifp = XFS_IFORK_PTR(cur->bc_ino.ip,
308 				    cur->bc_ino.whichfork);
309 
310 		return xfs_bmbt_maxrecs(cur->bc_mp,
311 					ifp->if_broot_bytes, level == 0) / 2;
312 	}
313 
314 	return cur->bc_mp->m_bmap_dmnr[level != 0];
315 }
316 
317 int
318 xfs_bmbt_get_maxrecs(
319 	struct xfs_btree_cur	*cur,
320 	int			level)
321 {
322 	if (level == cur->bc_nlevels - 1) {
323 		struct xfs_ifork	*ifp;
324 
325 		ifp = XFS_IFORK_PTR(cur->bc_ino.ip,
326 				    cur->bc_ino.whichfork);
327 
328 		return xfs_bmbt_maxrecs(cur->bc_mp,
329 					ifp->if_broot_bytes, level == 0);
330 	}
331 
332 	return cur->bc_mp->m_bmap_dmxr[level != 0];
333 
334 }
335 
336 /*
337  * Get the maximum records we could store in the on-disk format.
338  *
339  * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
340  * for the root node this checks the available space in the dinode fork
341  * so that we can resize the in-memory buffer to match it.  After a
342  * resize to the maximum size this function returns the same value
343  * as xfs_bmbt_get_maxrecs for the root node, too.
344  */
345 STATIC int
346 xfs_bmbt_get_dmaxrecs(
347 	struct xfs_btree_cur	*cur,
348 	int			level)
349 {
350 	if (level != cur->bc_nlevels - 1)
351 		return cur->bc_mp->m_bmap_dmxr[level != 0];
352 	return xfs_bmdr_maxrecs(cur->bc_ino.forksize, level == 0);
353 }
354 
355 STATIC void
356 xfs_bmbt_init_key_from_rec(
357 	union xfs_btree_key		*key,
358 	const union xfs_btree_rec	*rec)
359 {
360 	key->bmbt.br_startoff =
361 		cpu_to_be64(xfs_bmbt_disk_get_startoff(&rec->bmbt));
362 }
363 
364 STATIC void
365 xfs_bmbt_init_high_key_from_rec(
366 	union xfs_btree_key		*key,
367 	const union xfs_btree_rec	*rec)
368 {
369 	key->bmbt.br_startoff = cpu_to_be64(
370 			xfs_bmbt_disk_get_startoff(&rec->bmbt) +
371 			xfs_bmbt_disk_get_blockcount(&rec->bmbt) - 1);
372 }
373 
374 STATIC void
375 xfs_bmbt_init_rec_from_cur(
376 	struct xfs_btree_cur	*cur,
377 	union xfs_btree_rec	*rec)
378 {
379 	xfs_bmbt_disk_set_all(&rec->bmbt, &cur->bc_rec.b);
380 }
381 
382 STATIC void
383 xfs_bmbt_init_ptr_from_cur(
384 	struct xfs_btree_cur	*cur,
385 	union xfs_btree_ptr	*ptr)
386 {
387 	ptr->l = 0;
388 }
389 
390 STATIC int64_t
391 xfs_bmbt_key_diff(
392 	struct xfs_btree_cur		*cur,
393 	const union xfs_btree_key	*key)
394 {
395 	return (int64_t)be64_to_cpu(key->bmbt.br_startoff) -
396 				      cur->bc_rec.b.br_startoff;
397 }
398 
399 STATIC int64_t
400 xfs_bmbt_diff_two_keys(
401 	struct xfs_btree_cur		*cur,
402 	const union xfs_btree_key	*k1,
403 	const union xfs_btree_key	*k2)
404 {
405 	uint64_t			a = be64_to_cpu(k1->bmbt.br_startoff);
406 	uint64_t			b = be64_to_cpu(k2->bmbt.br_startoff);
407 
408 	/*
409 	 * Note: This routine previously casted a and b to int64 and subtracted
410 	 * them to generate a result.  This lead to problems if b was the
411 	 * "maximum" key value (all ones) being signed incorrectly, hence this
412 	 * somewhat less efficient version.
413 	 */
414 	if (a > b)
415 		return 1;
416 	if (b > a)
417 		return -1;
418 	return 0;
419 }
420 
421 static xfs_failaddr_t
422 xfs_bmbt_verify(
423 	struct xfs_buf		*bp)
424 {
425 	struct xfs_mount	*mp = bp->b_mount;
426 	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
427 	xfs_failaddr_t		fa;
428 	unsigned int		level;
429 
430 	if (!xfs_verify_magic(bp, block->bb_magic))
431 		return __this_address;
432 
433 	if (xfs_has_crc(mp)) {
434 		/*
435 		 * XXX: need a better way of verifying the owner here. Right now
436 		 * just make sure there has been one set.
437 		 */
438 		fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
439 		if (fa)
440 			return fa;
441 	}
442 
443 	/*
444 	 * numrecs and level verification.
445 	 *
446 	 * We don't know what fork we belong to, so just verify that the level
447 	 * is less than the maximum of the two. Later checks will be more
448 	 * precise.
449 	 */
450 	level = be16_to_cpu(block->bb_level);
451 	if (level > max(mp->m_bm_maxlevels[0], mp->m_bm_maxlevels[1]))
452 		return __this_address;
453 
454 	return xfs_btree_lblock_verify(bp, mp->m_bmap_dmxr[level != 0]);
455 }
456 
457 static void
458 xfs_bmbt_read_verify(
459 	struct xfs_buf	*bp)
460 {
461 	xfs_failaddr_t	fa;
462 
463 	if (!xfs_btree_lblock_verify_crc(bp))
464 		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
465 	else {
466 		fa = xfs_bmbt_verify(bp);
467 		if (fa)
468 			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
469 	}
470 
471 	if (bp->b_error)
472 		trace_xfs_btree_corrupt(bp, _RET_IP_);
473 }
474 
475 static void
476 xfs_bmbt_write_verify(
477 	struct xfs_buf	*bp)
478 {
479 	xfs_failaddr_t	fa;
480 
481 	fa = xfs_bmbt_verify(bp);
482 	if (fa) {
483 		trace_xfs_btree_corrupt(bp, _RET_IP_);
484 		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
485 		return;
486 	}
487 	xfs_btree_lblock_calc_crc(bp);
488 }
489 
490 const struct xfs_buf_ops xfs_bmbt_buf_ops = {
491 	.name = "xfs_bmbt",
492 	.magic = { cpu_to_be32(XFS_BMAP_MAGIC),
493 		   cpu_to_be32(XFS_BMAP_CRC_MAGIC) },
494 	.verify_read = xfs_bmbt_read_verify,
495 	.verify_write = xfs_bmbt_write_verify,
496 	.verify_struct = xfs_bmbt_verify,
497 };
498 
499 
500 STATIC int
501 xfs_bmbt_keys_inorder(
502 	struct xfs_btree_cur		*cur,
503 	const union xfs_btree_key	*k1,
504 	const union xfs_btree_key	*k2)
505 {
506 	return be64_to_cpu(k1->bmbt.br_startoff) <
507 		be64_to_cpu(k2->bmbt.br_startoff);
508 }
509 
510 STATIC int
511 xfs_bmbt_recs_inorder(
512 	struct xfs_btree_cur		*cur,
513 	const union xfs_btree_rec	*r1,
514 	const union xfs_btree_rec	*r2)
515 {
516 	return xfs_bmbt_disk_get_startoff(&r1->bmbt) +
517 		xfs_bmbt_disk_get_blockcount(&r1->bmbt) <=
518 		xfs_bmbt_disk_get_startoff(&r2->bmbt);
519 }
520 
521 static const struct xfs_btree_ops xfs_bmbt_ops = {
522 	.rec_len		= sizeof(xfs_bmbt_rec_t),
523 	.key_len		= sizeof(xfs_bmbt_key_t),
524 
525 	.dup_cursor		= xfs_bmbt_dup_cursor,
526 	.update_cursor		= xfs_bmbt_update_cursor,
527 	.alloc_block		= xfs_bmbt_alloc_block,
528 	.free_block		= xfs_bmbt_free_block,
529 	.get_maxrecs		= xfs_bmbt_get_maxrecs,
530 	.get_minrecs		= xfs_bmbt_get_minrecs,
531 	.get_dmaxrecs		= xfs_bmbt_get_dmaxrecs,
532 	.init_key_from_rec	= xfs_bmbt_init_key_from_rec,
533 	.init_high_key_from_rec	= xfs_bmbt_init_high_key_from_rec,
534 	.init_rec_from_cur	= xfs_bmbt_init_rec_from_cur,
535 	.init_ptr_from_cur	= xfs_bmbt_init_ptr_from_cur,
536 	.key_diff		= xfs_bmbt_key_diff,
537 	.diff_two_keys		= xfs_bmbt_diff_two_keys,
538 	.buf_ops		= &xfs_bmbt_buf_ops,
539 	.keys_inorder		= xfs_bmbt_keys_inorder,
540 	.recs_inorder		= xfs_bmbt_recs_inorder,
541 };
542 
543 /*
544  * Allocate a new bmap btree cursor.
545  */
546 struct xfs_btree_cur *				/* new bmap btree cursor */
547 xfs_bmbt_init_cursor(
548 	struct xfs_mount	*mp,		/* file system mount point */
549 	struct xfs_trans	*tp,		/* transaction pointer */
550 	struct xfs_inode	*ip,		/* inode owning the btree */
551 	int			whichfork)	/* data or attr fork */
552 {
553 	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
554 	struct xfs_btree_cur	*cur;
555 	ASSERT(whichfork != XFS_COW_FORK);
556 
557 	cur = xfs_btree_alloc_cursor(mp, tp, XFS_BTNUM_BMAP,
558 			mp->m_bm_maxlevels[whichfork], xfs_bmbt_cur_cache);
559 	cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
560 	cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_bmbt_2);
561 
562 	cur->bc_ops = &xfs_bmbt_ops;
563 	cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE;
564 	if (xfs_has_crc(mp))
565 		cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
566 
567 	cur->bc_ino.forksize = XFS_IFORK_SIZE(ip, whichfork);
568 	cur->bc_ino.ip = ip;
569 	cur->bc_ino.allocated = 0;
570 	cur->bc_ino.flags = 0;
571 	cur->bc_ino.whichfork = whichfork;
572 
573 	return cur;
574 }
575 
576 /* Calculate number of records in a block mapping btree block. */
577 static inline unsigned int
578 xfs_bmbt_block_maxrecs(
579 	unsigned int		blocklen,
580 	bool			leaf)
581 {
582 	if (leaf)
583 		return blocklen / sizeof(xfs_bmbt_rec_t);
584 	return blocklen / (sizeof(xfs_bmbt_key_t) + sizeof(xfs_bmbt_ptr_t));
585 }
586 
587 /*
588  * Calculate number of records in a bmap btree block.
589  */
590 int
591 xfs_bmbt_maxrecs(
592 	struct xfs_mount	*mp,
593 	int			blocklen,
594 	int			leaf)
595 {
596 	blocklen -= XFS_BMBT_BLOCK_LEN(mp);
597 	return xfs_bmbt_block_maxrecs(blocklen, leaf);
598 }
599 
600 /*
601  * Calculate the maximum possible height of the btree that the on-disk format
602  * supports. This is used for sizing structures large enough to support every
603  * possible configuration of a filesystem that might get mounted.
604  */
605 unsigned int
606 xfs_bmbt_maxlevels_ondisk(void)
607 {
608 	unsigned int		minrecs[2];
609 	unsigned int		blocklen;
610 
611 	blocklen = min(XFS_MIN_BLOCKSIZE - XFS_BTREE_SBLOCK_LEN,
612 		       XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_SBLOCK_CRC_LEN);
613 
614 	minrecs[0] = xfs_bmbt_block_maxrecs(blocklen, true) / 2;
615 	minrecs[1] = xfs_bmbt_block_maxrecs(blocklen, false) / 2;
616 
617 	/* One extra level for the inode root. */
618 	return xfs_btree_compute_maxlevels(minrecs,
619 			XFS_MAX_EXTCNT_DATA_FORK_LARGE) + 1;
620 }
621 
622 /*
623  * Calculate number of records in a bmap btree inode root.
624  */
625 int
626 xfs_bmdr_maxrecs(
627 	int			blocklen,
628 	int			leaf)
629 {
630 	blocklen -= sizeof(xfs_bmdr_block_t);
631 
632 	if (leaf)
633 		return blocklen / sizeof(xfs_bmdr_rec_t);
634 	return blocklen / (sizeof(xfs_bmdr_key_t) + sizeof(xfs_bmdr_ptr_t));
635 }
636 
637 /*
638  * Change the owner of a btree format fork fo the inode passed in. Change it to
639  * the owner of that is passed in so that we can change owners before or after
640  * we switch forks between inodes. The operation that the caller is doing will
641  * determine whether is needs to change owner before or after the switch.
642  *
643  * For demand paged transactional modification, the fork switch should be done
644  * after reading in all the blocks, modifying them and pinning them in the
645  * transaction. For modification when the buffers are already pinned in memory,
646  * the fork switch can be done before changing the owner as we won't need to
647  * validate the owner until the btree buffers are unpinned and writes can occur
648  * again.
649  *
650  * For recovery based ownership change, there is no transactional context and
651  * so a buffer list must be supplied so that we can record the buffers that we
652  * modified for the caller to issue IO on.
653  */
654 int
655 xfs_bmbt_change_owner(
656 	struct xfs_trans	*tp,
657 	struct xfs_inode	*ip,
658 	int			whichfork,
659 	xfs_ino_t		new_owner,
660 	struct list_head	*buffer_list)
661 {
662 	struct xfs_btree_cur	*cur;
663 	int			error;
664 
665 	ASSERT(tp || buffer_list);
666 	ASSERT(!(tp && buffer_list));
667 	ASSERT(XFS_IFORK_PTR(ip, whichfork)->if_format == XFS_DINODE_FMT_BTREE);
668 
669 	cur = xfs_bmbt_init_cursor(ip->i_mount, tp, ip, whichfork);
670 	cur->bc_ino.flags |= XFS_BTCUR_BMBT_INVALID_OWNER;
671 
672 	error = xfs_btree_change_owner(cur, new_owner, buffer_list);
673 	xfs_btree_del_cursor(cur, error);
674 	return error;
675 }
676 
677 /* Calculate the bmap btree size for some records. */
678 unsigned long long
679 xfs_bmbt_calc_size(
680 	struct xfs_mount	*mp,
681 	unsigned long long	len)
682 {
683 	return xfs_btree_calc_size(mp->m_bmap_dmnr, len);
684 }
685 
686 int __init
687 xfs_bmbt_init_cur_cache(void)
688 {
689 	xfs_bmbt_cur_cache = kmem_cache_create("xfs_bmbt_cur",
690 			xfs_btree_cur_sizeof(xfs_bmbt_maxlevels_ondisk()),
691 			0, 0, NULL);
692 
693 	if (!xfs_bmbt_cur_cache)
694 		return -ENOMEM;
695 	return 0;
696 }
697 
698 void
699 xfs_bmbt_destroy_cur_cache(void)
700 {
701 	kmem_cache_destroy(xfs_bmbt_cur_cache);
702 	xfs_bmbt_cur_cache = NULL;
703 }
704