1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (c) 2000-2002,2005 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_buf_item.h"
  17#include "xfs_btree.h"
  18#include "xfs_errortag.h"
  19#include "xfs_error.h"
  20#include "xfs_trace.h"
  21#include "xfs_alloc.h"
  22#include "xfs_log.h"
  23#include "xfs_btree_staging.h"
  24#include "xfs_ag.h"
  25#include "xfs_alloc_btree.h"
  26#include "xfs_ialloc_btree.h"
  27#include "xfs_bmap_btree.h"
  28#include "xfs_rmap_btree.h"
  29#include "xfs_refcount_btree.h"
  30#include "xfs_health.h"
  31#include "xfs_buf_mem.h"
  32#include "xfs_btree_mem.h"
  33
  34/*
  35 * Btree magic numbers.
  36 */
 
 
 
 
 
 
 
 
  37uint32_t
  38xfs_btree_magic(
  39	struct xfs_mount		*mp,
  40	const struct xfs_btree_ops	*ops)
  41{
  42	int				idx = xfs_has_crc(mp) ? 1 : 0;
  43	__be32				magic = ops->buf_ops->magic[idx];
  44
  45	/* Ensure we asked for crc for crc-only magics. */
  46	ASSERT(magic != 0);
  47	return be32_to_cpu(magic);
  48}
  49
  50/*
  51 * These sibling pointer checks are optimised for null sibling pointers. This
  52 * happens a lot, and we don't need to byte swap at runtime if the sibling
  53 * pointer is NULL.
  54 *
  55 * These are explicitly marked at inline because the cost of calling them as
  56 * functions instead of inlining them is about 36 bytes extra code per call site
  57 * on x86-64. Yes, gcc-11 fails to inline them, and explicit inlining of these
  58 * two sibling check functions reduces the compiled code size by over 300
  59 * bytes.
  60 */
  61static inline xfs_failaddr_t
  62xfs_btree_check_fsblock_siblings(
  63	struct xfs_mount	*mp,
  64	xfs_fsblock_t		fsb,
  65	__be64			dsibling)
  66{
  67	xfs_fsblock_t		sibling;
  68
  69	if (dsibling == cpu_to_be64(NULLFSBLOCK))
  70		return NULL;
  71
  72	sibling = be64_to_cpu(dsibling);
  73	if (sibling == fsb)
  74		return __this_address;
  75	if (!xfs_verify_fsbno(mp, sibling))
  76		return __this_address;
  77	return NULL;
  78}
  79
  80static inline xfs_failaddr_t
  81xfs_btree_check_memblock_siblings(
  82	struct xfs_buftarg	*btp,
  83	xfbno_t			bno,
  84	__be64			dsibling)
  85{
  86	xfbno_t			sibling;
  87
  88	if (dsibling == cpu_to_be64(NULLFSBLOCK))
  89		return NULL;
  90
  91	sibling = be64_to_cpu(dsibling);
  92	if (sibling == bno)
  93		return __this_address;
  94	if (!xmbuf_verify_daddr(btp, xfbno_to_daddr(sibling)))
  95		return __this_address;
  96	return NULL;
  97}
  98
  99static inline xfs_failaddr_t
 100xfs_btree_check_agblock_siblings(
 101	struct xfs_perag	*pag,
 102	xfs_agblock_t		agbno,
 103	__be32			dsibling)
 104{
 105	xfs_agblock_t		sibling;
 106
 107	if (dsibling == cpu_to_be32(NULLAGBLOCK))
 108		return NULL;
 109
 110	sibling = be32_to_cpu(dsibling);
 111	if (sibling == agbno)
 112		return __this_address;
 113	if (!xfs_verify_agbno(pag, sibling))
 114		return __this_address;
 115	return NULL;
 116}
 117
 118static xfs_failaddr_t
 119__xfs_btree_check_lblock_hdr(
 120	struct xfs_btree_cur	*cur,
 121	struct xfs_btree_block	*block,
 122	int			level,
 123	struct xfs_buf		*bp)
 124{
 125	struct xfs_mount	*mp = cur->bc_mp;
 
 
 126
 127	if (xfs_has_crc(mp)) {
 128		if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
 129			return __this_address;
 130		if (block->bb_u.l.bb_blkno !=
 131		    cpu_to_be64(bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL))
 132			return __this_address;
 133		if (block->bb_u.l.bb_pad != cpu_to_be32(0))
 134			return __this_address;
 135	}
 136
 137	if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(mp, cur->bc_ops))
 138		return __this_address;
 139	if (be16_to_cpu(block->bb_level) != level)
 140		return __this_address;
 141	if (be16_to_cpu(block->bb_numrecs) >
 142	    cur->bc_ops->get_maxrecs(cur, level))
 143		return __this_address;
 
 
 
 
 
 
 
 
 144
 145	return NULL;
 146}
 147
 148/*
 149 * Check a long btree block header.  Return the address of the failing check,
 150 * or NULL if everything is ok.
 151 */
 152static xfs_failaddr_t
 153__xfs_btree_check_fsblock(
 154	struct xfs_btree_cur	*cur,
 155	struct xfs_btree_block	*block,
 156	int			level,
 157	struct xfs_buf		*bp)
 158{
 159	struct xfs_mount	*mp = cur->bc_mp;
 160	xfs_failaddr_t		fa;
 161	xfs_fsblock_t		fsb;
 162
 163	fa = __xfs_btree_check_lblock_hdr(cur, block, level, bp);
 164	if (fa)
 165		return fa;
 166
 167	/*
 168	 * For inode-rooted btrees, the root block sits in the inode fork.  In
 169	 * that case bp is NULL, and the block must not have any siblings.
 170	 */
 171	if (!bp) {
 172		if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK))
 173			return __this_address;
 174		if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK))
 175			return __this_address;
 176		return NULL;
 177	}
 178
 179	fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
 180	fa = xfs_btree_check_fsblock_siblings(mp, fsb,
 181			block->bb_u.l.bb_leftsib);
 182	if (!fa)
 183		fa = xfs_btree_check_fsblock_siblings(mp, fsb,
 184				block->bb_u.l.bb_rightsib);
 185	return fa;
 186}
 187
 188/*
 189 * Check an in-memory btree block header.  Return the address of the failing
 190 * check, or NULL if everything is ok.
 191 */
 192static xfs_failaddr_t
 193__xfs_btree_check_memblock(
 194	struct xfs_btree_cur	*cur,
 195	struct xfs_btree_block	*block,
 196	int			level,
 197	struct xfs_buf		*bp)
 198{
 199	struct xfs_buftarg	*btp = cur->bc_mem.xfbtree->target;
 200	xfs_failaddr_t		fa;
 201	xfbno_t			bno;
 202
 203	fa = __xfs_btree_check_lblock_hdr(cur, block, level, bp);
 204	if (fa)
 205		return fa;
 206
 207	bno = xfs_daddr_to_xfbno(xfs_buf_daddr(bp));
 208	fa = xfs_btree_check_memblock_siblings(btp, bno,
 209			block->bb_u.l.bb_leftsib);
 210	if (!fa)
 211		fa = xfs_btree_check_memblock_siblings(btp, bno,
 212				block->bb_u.l.bb_rightsib);
 213	return fa;
 214}
 215
 216/*
 217 * Check a short btree block header.  Return the address of the failing check,
 218 * or NULL if everything is ok.
 219 */
 220static xfs_failaddr_t
 221__xfs_btree_check_agblock(
 222	struct xfs_btree_cur	*cur,
 223	struct xfs_btree_block	*block,
 224	int			level,
 225	struct xfs_buf		*bp)
 226{
 227	struct xfs_mount	*mp = cur->bc_mp;
 228	struct xfs_perag	*pag = cur->bc_ag.pag;
 229	xfs_failaddr_t		fa;
 230	xfs_agblock_t		agbno;
 231
 232	if (xfs_has_crc(mp)) {
 233		if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
 234			return __this_address;
 235		if (block->bb_u.s.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
 
 236			return __this_address;
 237	}
 238
 239	if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(mp, cur->bc_ops))
 240		return __this_address;
 241	if (be16_to_cpu(block->bb_level) != level)
 242		return __this_address;
 243	if (be16_to_cpu(block->bb_numrecs) >
 244	    cur->bc_ops->get_maxrecs(cur, level))
 245		return __this_address;
 
 
 
 
 
 
 
 
 246
 247	agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
 248	fa = xfs_btree_check_agblock_siblings(pag, agbno,
 249			block->bb_u.s.bb_leftsib);
 250	if (!fa)
 251		fa = xfs_btree_check_agblock_siblings(pag, agbno,
 252				block->bb_u.s.bb_rightsib);
 253	return fa;
 254}
 255
 256/*
 257 * Internal btree block check.
 258 *
 259 * Return NULL if the block is ok or the address of the failed check otherwise.
 260 */
 261xfs_failaddr_t
 262__xfs_btree_check_block(
 263	struct xfs_btree_cur	*cur,
 264	struct xfs_btree_block	*block,
 265	int			level,
 266	struct xfs_buf		*bp)
 267{
 268	switch (cur->bc_ops->type) {
 269	case XFS_BTREE_TYPE_MEM:
 270		return __xfs_btree_check_memblock(cur, block, level, bp);
 271	case XFS_BTREE_TYPE_AG:
 272		return __xfs_btree_check_agblock(cur, block, level, bp);
 273	case XFS_BTREE_TYPE_INODE:
 274		return __xfs_btree_check_fsblock(cur, block, level, bp);
 275	default:
 276		ASSERT(0);
 277		return __this_address;
 278	}
 279}
 280
 281static inline unsigned int xfs_btree_block_errtag(struct xfs_btree_cur *cur)
 282{
 283	if (cur->bc_ops->ptr_len == XFS_BTREE_SHORT_PTR_LEN)
 284		return XFS_ERRTAG_BTREE_CHECK_SBLOCK;
 285	return XFS_ERRTAG_BTREE_CHECK_LBLOCK;
 
 
 
 
 286}
 287
 288/*
 289 * Debug routine: check that block header is ok.
 290 */
 291int
 292xfs_btree_check_block(
 293	struct xfs_btree_cur	*cur,	/* btree cursor */
 294	struct xfs_btree_block	*block,	/* generic btree block pointer */
 295	int			level,	/* level of the btree block */
 296	struct xfs_buf		*bp)	/* buffer containing block, if any */
 297{
 298	struct xfs_mount	*mp = cur->bc_mp;
 299	xfs_failaddr_t		fa;
 300
 301	fa = __xfs_btree_check_block(cur, block, level, bp);
 302	if (XFS_IS_CORRUPT(mp, fa != NULL) ||
 303	    XFS_TEST_ERROR(false, mp, xfs_btree_block_errtag(cur))) {
 304		if (bp)
 305			trace_xfs_btree_corrupt(bp, _RET_IP_);
 306		xfs_btree_mark_sick(cur);
 307		return -EFSCORRUPTED;
 308	}
 309	return 0;
 310}
 311
 312int
 313__xfs_btree_check_ptr(
 314	struct xfs_btree_cur		*cur,
 315	const union xfs_btree_ptr	*ptr,
 316	int				index,
 317	int				level)
 318{
 319	if (level <= 0)
 320		return -EFSCORRUPTED;
 321
 322	switch (cur->bc_ops->type) {
 323	case XFS_BTREE_TYPE_MEM:
 324		if (!xfbtree_verify_bno(cur->bc_mem.xfbtree,
 325				be64_to_cpu((&ptr->l)[index])))
 326			return -EFSCORRUPTED;
 327		break;
 328	case XFS_BTREE_TYPE_INODE:
 329		if (!xfs_verify_fsbno(cur->bc_mp,
 330				be64_to_cpu((&ptr->l)[index])))
 331			return -EFSCORRUPTED;
 332		break;
 333	case XFS_BTREE_TYPE_AG:
 334		if (!xfs_verify_agbno(cur->bc_ag.pag,
 335				be32_to_cpu((&ptr->s)[index])))
 336			return -EFSCORRUPTED;
 337		break;
 338	}
 339
 340	return 0;
 
 
 
 
 
 
 
 
 
 341}
 342
 343/*
 344 * Check that a given (indexed) btree pointer at a certain level of a
 345 * btree is valid and doesn't point past where it should.
 346 */
 347static int
 348xfs_btree_check_ptr(
 349	struct xfs_btree_cur		*cur,
 350	const union xfs_btree_ptr	*ptr,
 351	int				index,
 352	int				level)
 353{
 354	int				error;
 355
 356	error = __xfs_btree_check_ptr(cur, ptr, index, level);
 357	if (error) {
 358		switch (cur->bc_ops->type) {
 359		case XFS_BTREE_TYPE_MEM:
 360			xfs_err(cur->bc_mp,
 361"In-memory: Corrupt %sbt flags 0x%x pointer at level %d index %d fa %pS.",
 362				cur->bc_ops->name, cur->bc_flags, level, index,
 363				__this_address);
 364			break;
 365		case XFS_BTREE_TYPE_INODE:
 366			xfs_err(cur->bc_mp,
 367"Inode %llu fork %d: Corrupt %sbt pointer at level %d index %d.",
 368				cur->bc_ino.ip->i_ino,
 369				cur->bc_ino.whichfork, cur->bc_ops->name,
 370				level, index);
 371			break;
 372		case XFS_BTREE_TYPE_AG:
 373			xfs_err(cur->bc_mp,
 374"AG %u: Corrupt %sbt pointer at level %d index %d.",
 375				cur->bc_ag.pag->pag_agno, cur->bc_ops->name,
 
 
 376				level, index);
 377			break;
 378		}
 379		xfs_btree_mark_sick(cur);
 380	}
 381
 382	return error;
 383}
 384
 385#ifdef DEBUG
 386# define xfs_btree_debug_check_ptr	xfs_btree_check_ptr
 387#else
 388# define xfs_btree_debug_check_ptr(...)	(0)
 389#endif
 390
 391/*
 392 * Calculate CRC on the whole btree block and stuff it into the
 393 * long-form btree header.
 394 *
 395 * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
 396 * it into the buffer so recovery knows what the last modification was that made
 397 * it to disk.
 398 */
 399void
 400xfs_btree_fsblock_calc_crc(
 401	struct xfs_buf		*bp)
 402{
 403	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
 404	struct xfs_buf_log_item	*bip = bp->b_log_item;
 405
 406	if (!xfs_has_crc(bp->b_mount))
 407		return;
 408	if (bip)
 409		block->bb_u.l.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
 410	xfs_buf_update_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
 411}
 412
 413bool
 414xfs_btree_fsblock_verify_crc(
 415	struct xfs_buf		*bp)
 416{
 417	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
 418	struct xfs_mount	*mp = bp->b_mount;
 419
 420	if (xfs_has_crc(mp)) {
 421		if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.l.bb_lsn)))
 422			return false;
 423		return xfs_buf_verify_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
 424	}
 425
 426	return true;
 427}
 428
 429/*
 430 * Calculate CRC on the whole btree block and stuff it into the
 431 * short-form btree header.
 432 *
 433 * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
 434 * it into the buffer so recovery knows what the last modification was that made
 435 * it to disk.
 436 */
 437void
 438xfs_btree_agblock_calc_crc(
 439	struct xfs_buf		*bp)
 440{
 441	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
 442	struct xfs_buf_log_item	*bip = bp->b_log_item;
 443
 444	if (!xfs_has_crc(bp->b_mount))
 445		return;
 446	if (bip)
 447		block->bb_u.s.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
 448	xfs_buf_update_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
 449}
 450
 451bool
 452xfs_btree_agblock_verify_crc(
 453	struct xfs_buf		*bp)
 454{
 455	struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 456	struct xfs_mount	*mp = bp->b_mount;
 457
 458	if (xfs_has_crc(mp)) {
 459		if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.s.bb_lsn)))
 460			return false;
 461		return xfs_buf_verify_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
 462	}
 463
 464	return true;
 465}
 466
 467static int
 468xfs_btree_free_block(
 469	struct xfs_btree_cur	*cur,
 470	struct xfs_buf		*bp)
 471{
 472	int			error;
 473
 474	trace_xfs_btree_free_block(cur, bp);
 475
 476	/*
 477	 * Don't allow block freeing for a staging cursor, because staging
 478	 * cursors do not support regular btree modifications.
 479	 */
 480	if (unlikely(cur->bc_flags & XFS_BTREE_STAGING)) {
 481		ASSERT(0);
 482		return -EFSCORRUPTED;
 483	}
 484
 485	error = cur->bc_ops->free_block(cur, bp);
 486	if (!error) {
 487		xfs_trans_binval(cur->bc_tp, bp);
 488		XFS_BTREE_STATS_INC(cur, free);
 489	}
 490	return error;
 491}
 492
 493/*
 494 * Delete the btree cursor.
 495 */
 496void
 497xfs_btree_del_cursor(
 498	struct xfs_btree_cur	*cur,		/* btree cursor */
 499	int			error)		/* del because of error */
 500{
 501	int			i;		/* btree level */
 502
 503	/*
 504	 * Clear the buffer pointers and release the buffers. If we're doing
 505	 * this because of an error, inspect all of the entries in the bc_bufs
 506	 * array for buffers to be unlocked. This is because some of the btree
 507	 * code works from level n down to 0, and if we get an error along the
 508	 * way we won't have initialized all the entries down to 0.
 
 
 
 509	 */
 510	for (i = 0; i < cur->bc_nlevels; i++) {
 511		if (cur->bc_levels[i].bp)
 512			xfs_trans_brelse(cur->bc_tp, cur->bc_levels[i].bp);
 513		else if (!error)
 514			break;
 515	}
 516
 517	/*
 518	 * If we are doing a BMBT update, the number of unaccounted blocks
 519	 * allocated during this cursor life time should be zero. If it's not
 520	 * zero, then we should be shut down or on our way to shutdown due to
 521	 * cancelling a dirty transaction on error.
 522	 */
 523	ASSERT(!xfs_btree_is_bmap(cur->bc_ops) || cur->bc_bmap.allocated == 0 ||
 524	       xfs_is_shutdown(cur->bc_mp) || error != 0);
 525
 526	switch (cur->bc_ops->type) {
 527	case XFS_BTREE_TYPE_AG:
 528		if (cur->bc_ag.pag)
 529			xfs_perag_put(cur->bc_ag.pag);
 530		break;
 531	case XFS_BTREE_TYPE_INODE:
 532		/* nothing to do */
 533		break;
 534	case XFS_BTREE_TYPE_MEM:
 535		if (cur->bc_mem.pag)
 536			xfs_perag_put(cur->bc_mem.pag);
 537		break;
 538	}
 539
 540	kmem_cache_free(cur->bc_cache, cur);
 541}
 542
 543/* Return the buffer target for this btree's buffer. */
 544static inline struct xfs_buftarg *
 545xfs_btree_buftarg(
 546	struct xfs_btree_cur	*cur)
 547{
 548	if (cur->bc_ops->type == XFS_BTREE_TYPE_MEM)
 549		return cur->bc_mem.xfbtree->target;
 550	return cur->bc_mp->m_ddev_targp;
 551}
 552
 553/* Return the block size (in units of 512b sectors) for this btree. */
 554static inline unsigned int
 555xfs_btree_bbsize(
 556	struct xfs_btree_cur	*cur)
 557{
 558	if (cur->bc_ops->type == XFS_BTREE_TYPE_MEM)
 559		return XFBNO_BBSIZE;
 560	return cur->bc_mp->m_bsize;
 561}
 562
 563/*
 564 * Duplicate the btree cursor.
 565 * Allocate a new one, copy the record, re-get the buffers.
 566 */
 567int						/* error */
 568xfs_btree_dup_cursor(
 569	struct xfs_btree_cur	*cur,		/* input cursor */
 570	struct xfs_btree_cur	**ncur)		/* output cursor */
 571{
 572	struct xfs_mount	*mp = cur->bc_mp;
 573	struct xfs_trans	*tp = cur->bc_tp;
 574	struct xfs_buf		*bp;
 575	struct xfs_btree_cur	*new;
 576	int			error;
 577	int			i;
 578
 579	/*
 580	 * Don't allow staging cursors to be duplicated because they're supposed
 581	 * to be kept private to a single thread.
 582	 */
 583	if (unlikely(cur->bc_flags & XFS_BTREE_STAGING)) {
 584		ASSERT(0);
 585		return -EFSCORRUPTED;
 586	}
 587
 588	/*
 589	 * Allocate a new cursor like the old one.
 590	 */
 591	new = cur->bc_ops->dup_cursor(cur);
 592
 593	/*
 594	 * Copy the record currently in the cursor.
 595	 */
 596	new->bc_rec = cur->bc_rec;
 597
 598	/*
 599	 * For each level current, re-get the buffer and copy the ptr value.
 600	 */
 601	for (i = 0; i < new->bc_nlevels; i++) {
 602		new->bc_levels[i].ptr = cur->bc_levels[i].ptr;
 603		new->bc_levels[i].ra = cur->bc_levels[i].ra;
 604		bp = cur->bc_levels[i].bp;
 605		if (bp) {
 606			error = xfs_trans_read_buf(mp, tp,
 607					xfs_btree_buftarg(cur),
 608					xfs_buf_daddr(bp),
 609					xfs_btree_bbsize(cur), 0, &bp,
 610					cur->bc_ops->buf_ops);
 611			if (xfs_metadata_is_sick(error))
 612				xfs_btree_mark_sick(new);
 613			if (error) {
 614				xfs_btree_del_cursor(new, error);
 615				*ncur = NULL;
 616				return error;
 617			}
 618		}
 619		new->bc_levels[i].bp = bp;
 620	}
 621	*ncur = new;
 622	return 0;
 623}
 624
 625/*
 626 * XFS btree block layout and addressing:
 627 *
 628 * There are two types of blocks in the btree: leaf and non-leaf blocks.
 629 *
 630 * The leaf record start with a header then followed by records containing
 631 * the values.  A non-leaf block also starts with the same header, and
 632 * then first contains lookup keys followed by an equal number of pointers
 633 * to the btree blocks at the previous level.
 634 *
 635 *		+--------+-------+-------+-------+-------+-------+-------+
 636 * Leaf:	| header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
 637 *		+--------+-------+-------+-------+-------+-------+-------+
 638 *
 639 *		+--------+-------+-------+-------+-------+-------+-------+
 640 * Non-Leaf:	| header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
 641 *		+--------+-------+-------+-------+-------+-------+-------+
 642 *
 643 * The header is called struct xfs_btree_block for reasons better left unknown
 644 * and comes in different versions for short (32bit) and long (64bit) block
 645 * pointers.  The record and key structures are defined by the btree instances
 646 * and opaque to the btree core.  The block pointers are simple disk endian
 647 * integers, available in a short (32bit) and long (64bit) variant.
 648 *
 649 * The helpers below calculate the offset of a given record, key or pointer
 650 * into a btree block (xfs_btree_*_offset) or return a pointer to the given
 651 * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
 652 * inside the btree block is done using indices starting at one, not zero!
 653 *
 654 * If XFS_BTGEO_OVERLAPPING is set, then this btree supports keys containing
 655 * overlapping intervals.  In such a tree, records are still sorted lowest to
 656 * highest and indexed by the smallest key value that refers to the record.
 657 * However, nodes are different: each pointer has two associated keys -- one
 658 * indexing the lowest key available in the block(s) below (the same behavior
 659 * as the key in a regular btree) and another indexing the highest key
 660 * available in the block(s) below.  Because records are /not/ sorted by the
 661 * highest key, all leaf block updates require us to compute the highest key
 662 * that matches any record in the leaf and to recursively update the high keys
 663 * in the nodes going further up in the tree, if necessary.  Nodes look like
 664 * this:
 665 *
 666 *		+--------+-----+-----+-----+-----+-----+-------+-------+-----+
 667 * Non-Leaf:	| header | lo1 | hi1 | lo2 | hi2 | ... | ptr 1 | ptr 2 | ... |
 668 *		+--------+-----+-----+-----+-----+-----+-------+-------+-----+
 669 *
 670 * To perform an interval query on an overlapped tree, perform the usual
 671 * depth-first search and use the low and high keys to decide if we can skip
 672 * that particular node.  If a leaf node is reached, return the records that
 673 * intersect the interval.  Note that an interval query may return numerous
 674 * entries.  For a non-overlapped tree, simply search for the record associated
 675 * with the lowest key and iterate forward until a non-matching record is
 676 * found.  Section 14.3 ("Interval Trees") of _Introduction to Algorithms_ by
 677 * Cormen, Leiserson, Rivest, and Stein (2nd or 3rd ed. only) discuss this in
 678 * more detail.
 679 *
 680 * Why do we care about overlapping intervals?  Let's say you have a bunch of
 681 * reverse mapping records on a reflink filesystem:
 682 *
 683 * 1: +- file A startblock B offset C length D -----------+
 684 * 2:      +- file E startblock F offset G length H --------------+
 685 * 3:      +- file I startblock F offset J length K --+
 686 * 4:                                                        +- file L... --+
 687 *
 688 * Now say we want to map block (B+D) into file A at offset (C+D).  Ideally,
 689 * we'd simply increment the length of record 1.  But how do we find the record
 690 * that ends at (B+D-1) (i.e. record 1)?  A LE lookup of (B+D-1) would return
 691 * record 3 because the keys are ordered first by startblock.  An interval
 692 * query would return records 1 and 2 because they both overlap (B+D-1), and
 693 * from that we can pick out record 1 as the appropriate left neighbor.
 694 *
 695 * In the non-overlapped case you can do a LE lookup and decrement the cursor
 696 * because a record's interval must end before the next record.
 697 */
 698
 699/*
 700 * Return size of the btree block header for this btree instance.
 701 */
 702static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
 703{
 704	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
 705		if (xfs_has_crc(cur->bc_mp))
 706			return XFS_BTREE_LBLOCK_CRC_LEN;
 707		return XFS_BTREE_LBLOCK_LEN;
 708	}
 709	if (xfs_has_crc(cur->bc_mp))
 710		return XFS_BTREE_SBLOCK_CRC_LEN;
 711	return XFS_BTREE_SBLOCK_LEN;
 712}
 713
 714/*
 
 
 
 
 
 
 
 
 
 715 * Calculate offset of the n-th record in a btree block.
 716 */
 717STATIC size_t
 718xfs_btree_rec_offset(
 719	struct xfs_btree_cur	*cur,
 720	int			n)
 721{
 722	return xfs_btree_block_len(cur) +
 723		(n - 1) * cur->bc_ops->rec_len;
 724}
 725
 726/*
 727 * Calculate offset of the n-th key in a btree block.
 728 */
 729STATIC size_t
 730xfs_btree_key_offset(
 731	struct xfs_btree_cur	*cur,
 732	int			n)
 733{
 734	return xfs_btree_block_len(cur) +
 735		(n - 1) * cur->bc_ops->key_len;
 736}
 737
 738/*
 739 * Calculate offset of the n-th high key in a btree block.
 740 */
 741STATIC size_t
 742xfs_btree_high_key_offset(
 743	struct xfs_btree_cur	*cur,
 744	int			n)
 745{
 746	return xfs_btree_block_len(cur) +
 747		(n - 1) * cur->bc_ops->key_len + (cur->bc_ops->key_len / 2);
 748}
 749
 750/*
 751 * Calculate offset of the n-th block pointer in a btree block.
 752 */
 753STATIC size_t
 754xfs_btree_ptr_offset(
 755	struct xfs_btree_cur	*cur,
 756	int			n,
 757	int			level)
 758{
 759	return xfs_btree_block_len(cur) +
 760		cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
 761		(n - 1) * cur->bc_ops->ptr_len;
 762}
 763
 764/*
 765 * Return a pointer to the n-th record in the btree block.
 766 */
 767union xfs_btree_rec *
 768xfs_btree_rec_addr(
 769	struct xfs_btree_cur	*cur,
 770	int			n,
 771	struct xfs_btree_block	*block)
 772{
 773	return (union xfs_btree_rec *)
 774		((char *)block + xfs_btree_rec_offset(cur, n));
 775}
 776
 777/*
 778 * Return a pointer to the n-th key in the btree block.
 779 */
 780union xfs_btree_key *
 781xfs_btree_key_addr(
 782	struct xfs_btree_cur	*cur,
 783	int			n,
 784	struct xfs_btree_block	*block)
 785{
 786	return (union xfs_btree_key *)
 787		((char *)block + xfs_btree_key_offset(cur, n));
 788}
 789
 790/*
 791 * Return a pointer to the n-th high key in the btree block.
 792 */
 793union xfs_btree_key *
 794xfs_btree_high_key_addr(
 795	struct xfs_btree_cur	*cur,
 796	int			n,
 797	struct xfs_btree_block	*block)
 798{
 799	return (union xfs_btree_key *)
 800		((char *)block + xfs_btree_high_key_offset(cur, n));
 801}
 802
 803/*
 804 * Return a pointer to the n-th block pointer in the btree block.
 805 */
 806union xfs_btree_ptr *
 807xfs_btree_ptr_addr(
 808	struct xfs_btree_cur	*cur,
 809	int			n,
 810	struct xfs_btree_block	*block)
 811{
 812	int			level = xfs_btree_get_level(block);
 813
 814	ASSERT(block->bb_level != 0);
 815
 816	return (union xfs_btree_ptr *)
 817		((char *)block + xfs_btree_ptr_offset(cur, n, level));
 818}
 819
 820struct xfs_ifork *
 821xfs_btree_ifork_ptr(
 822	struct xfs_btree_cur	*cur)
 823{
 824	ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_INODE);
 825
 826	if (cur->bc_flags & XFS_BTREE_STAGING)
 827		return cur->bc_ino.ifake->if_fork;
 828	return xfs_ifork_ptr(cur->bc_ino.ip, cur->bc_ino.whichfork);
 829}
 830
 831/*
 832 * Get the root block which is stored in the inode.
 833 *
 834 * For now this btree implementation assumes the btree root is always
 835 * stored in the if_broot field of an inode fork.
 836 */
 837STATIC struct xfs_btree_block *
 838xfs_btree_get_iroot(
 839	struct xfs_btree_cur	*cur)
 840{
 841	struct xfs_ifork	*ifp = xfs_btree_ifork_ptr(cur);
 842
 
 843	return (struct xfs_btree_block *)ifp->if_broot;
 844}
 845
 846/*
 847 * Retrieve the block pointer from the cursor at the given level.
 848 * This may be an inode btree root or from a buffer.
 849 */
 850struct xfs_btree_block *		/* generic btree block pointer */
 851xfs_btree_get_block(
 852	struct xfs_btree_cur	*cur,	/* btree cursor */
 853	int			level,	/* level in btree */
 854	struct xfs_buf		**bpp)	/* buffer containing the block */
 855{
 856	if (xfs_btree_at_iroot(cur, level)) {
 
 857		*bpp = NULL;
 858		return xfs_btree_get_iroot(cur);
 859	}
 860
 861	*bpp = cur->bc_levels[level].bp;
 862	return XFS_BUF_TO_BLOCK(*bpp);
 863}
 864
 865/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 866 * Change the cursor to point to the first record at the given level.
 867 * Other levels are unaffected.
 868 */
 869STATIC int				/* success=1, failure=0 */
 870xfs_btree_firstrec(
 871	struct xfs_btree_cur	*cur,	/* btree cursor */
 872	int			level)	/* level to change */
 873{
 874	struct xfs_btree_block	*block;	/* generic btree block pointer */
 875	struct xfs_buf		*bp;	/* buffer containing block */
 876
 877	/*
 878	 * Get the block pointer for this level.
 879	 */
 880	block = xfs_btree_get_block(cur, level, &bp);
 881	if (xfs_btree_check_block(cur, block, level, bp))
 882		return 0;
 883	/*
 884	 * It's empty, there is no such record.
 885	 */
 886	if (!block->bb_numrecs)
 887		return 0;
 888	/*
 889	 * Set the ptr value to 1, that's the first record/key.
 890	 */
 891	cur->bc_levels[level].ptr = 1;
 892	return 1;
 893}
 894
 895/*
 896 * Change the cursor to point to the last record in the current block
 897 * at the given level.  Other levels are unaffected.
 898 */
 899STATIC int				/* success=1, failure=0 */
 900xfs_btree_lastrec(
 901	struct xfs_btree_cur	*cur,	/* btree cursor */
 902	int			level)	/* level to change */
 903{
 904	struct xfs_btree_block	*block;	/* generic btree block pointer */
 905	struct xfs_buf		*bp;	/* buffer containing block */
 906
 907	/*
 908	 * Get the block pointer for this level.
 909	 */
 910	block = xfs_btree_get_block(cur, level, &bp);
 911	if (xfs_btree_check_block(cur, block, level, bp))
 912		return 0;
 913	/*
 914	 * It's empty, there is no such record.
 915	 */
 916	if (!block->bb_numrecs)
 917		return 0;
 918	/*
 919	 * Set the ptr value to numrecs, that's the last record/key.
 920	 */
 921	cur->bc_levels[level].ptr = be16_to_cpu(block->bb_numrecs);
 922	return 1;
 923}
 924
 925/*
 926 * Compute first and last byte offsets for the fields given.
 927 * Interprets the offsets table, which contains struct field offsets.
 928 */
 929void
 930xfs_btree_offsets(
 931	uint32_t	fields,		/* bitmask of fields */
 932	const short	*offsets,	/* table of field offsets */
 933	int		nbits,		/* number of bits to inspect */
 934	int		*first,		/* output: first byte offset */
 935	int		*last)		/* output: last byte offset */
 936{
 937	int		i;		/* current bit number */
 938	uint32_t	imask;		/* mask for current bit number */
 939
 940	ASSERT(fields != 0);
 941	/*
 942	 * Find the lowest bit, so the first byte offset.
 943	 */
 944	for (i = 0, imask = 1u; ; i++, imask <<= 1) {
 945		if (imask & fields) {
 946			*first = offsets[i];
 947			break;
 948		}
 949	}
 950	/*
 951	 * Find the highest bit, so the last byte offset.
 952	 */
 953	for (i = nbits - 1, imask = 1u << i; ; i--, imask >>= 1) {
 954		if (imask & fields) {
 955			*last = offsets[i + 1] - 1;
 956			break;
 957		}
 958	}
 959}
 960
 961STATIC int
 962xfs_btree_readahead_fsblock(
 963	struct xfs_btree_cur	*cur,
 964	int			lr,
 965	struct xfs_btree_block	*block)
 
 
 
 
 
 
 
 966{
 967	struct xfs_mount	*mp = cur->bc_mp;
 968	xfs_fsblock_t		left = be64_to_cpu(block->bb_u.l.bb_leftsib);
 969	xfs_fsblock_t		right = be64_to_cpu(block->bb_u.l.bb_rightsib);
 970	int			rval = 0;
 971
 972	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLFSBLOCK) {
 973		xfs_buf_readahead(mp->m_ddev_targp, XFS_FSB_TO_DADDR(mp, left),
 974				mp->m_bsize, cur->bc_ops->buf_ops);
 975		rval++;
 976	}
 
 
 
 
 
 
 
 977
 978	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLFSBLOCK) {
 979		xfs_buf_readahead(mp->m_ddev_targp, XFS_FSB_TO_DADDR(mp, right),
 980				mp->m_bsize, cur->bc_ops->buf_ops);
 981		rval++;
 982	}
 
 
 
 
 
 
 
 
 983
 984	return rval;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 985}
 986
 987STATIC int
 988xfs_btree_readahead_memblock(
 989	struct xfs_btree_cur	*cur,
 990	int			lr,
 991	struct xfs_btree_block	*block)
 992{
 993	struct xfs_buftarg	*btp = cur->bc_mem.xfbtree->target;
 994	xfbno_t			left = be64_to_cpu(block->bb_u.l.bb_leftsib);
 995	xfbno_t			right = be64_to_cpu(block->bb_u.l.bb_rightsib);
 996	int			rval = 0;
 
 
 997
 998	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLFSBLOCK) {
 999		xfs_buf_readahead(btp, xfbno_to_daddr(left), XFBNO_BBSIZE,
1000				cur->bc_ops->buf_ops);
1001		rval++;
1002	}
1003
1004	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLFSBLOCK) {
1005		xfs_buf_readahead(btp, xfbno_to_daddr(right), XFBNO_BBSIZE,
1006				cur->bc_ops->buf_ops);
1007		rval++;
1008	}
1009
1010	return rval;
1011}
1012
1013STATIC int
1014xfs_btree_readahead_agblock(
1015	struct xfs_btree_cur	*cur,
1016	int			lr,
1017	struct xfs_btree_block	*block)
1018{
1019	struct xfs_mount	*mp = cur->bc_mp;
1020	xfs_agnumber_t		agno = cur->bc_ag.pag->pag_agno;
1021	xfs_agblock_t		left = be32_to_cpu(block->bb_u.s.bb_leftsib);
1022	xfs_agblock_t		right = be32_to_cpu(block->bb_u.s.bb_rightsib);
1023	int			rval = 0;
1024
1025	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
1026		xfs_buf_readahead(mp->m_ddev_targp,
1027				XFS_AGB_TO_DADDR(mp, agno, left),
1028				mp->m_bsize, cur->bc_ops->buf_ops);
1029		rval++;
1030	}
1031
1032	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
1033		xfs_buf_readahead(mp->m_ddev_targp,
1034				XFS_AGB_TO_DADDR(mp, agno, right),
1035				mp->m_bsize, cur->bc_ops->buf_ops);
1036		rval++;
1037	}
1038
1039	return rval;
1040}
1041
1042/*
1043 * Read-ahead btree blocks, at the given level.
1044 * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
1045 */
1046STATIC int
1047xfs_btree_readahead(
1048	struct xfs_btree_cur	*cur,		/* btree cursor */
1049	int			lev,		/* level in btree */
1050	int			lr)		/* left/right bits */
1051{
1052	struct xfs_btree_block	*block;
1053
1054	/*
1055	 * No readahead needed if we are at the root level and the
1056	 * btree root is stored in the inode.
1057	 */
1058	if (xfs_btree_at_iroot(cur, lev))
 
1059		return 0;
1060
1061	if ((cur->bc_levels[lev].ra | lr) == cur->bc_levels[lev].ra)
1062		return 0;
1063
1064	cur->bc_levels[lev].ra |= lr;
1065	block = XFS_BUF_TO_BLOCK(cur->bc_levels[lev].bp);
1066
1067	switch (cur->bc_ops->type) {
1068	case XFS_BTREE_TYPE_AG:
1069		return xfs_btree_readahead_agblock(cur, lr, block);
1070	case XFS_BTREE_TYPE_INODE:
1071		return xfs_btree_readahead_fsblock(cur, lr, block);
1072	case XFS_BTREE_TYPE_MEM:
1073		return xfs_btree_readahead_memblock(cur, lr, block);
1074	default:
1075		ASSERT(0);
1076		return 0;
1077	}
1078}
1079
1080STATIC int
1081xfs_btree_ptr_to_daddr(
1082	struct xfs_btree_cur		*cur,
1083	const union xfs_btree_ptr	*ptr,
1084	xfs_daddr_t			*daddr)
1085{
 
 
1086	int			error;
1087
1088	error = xfs_btree_check_ptr(cur, ptr, 0, 1);
1089	if (error)
1090		return error;
1091
1092	switch (cur->bc_ops->type) {
1093	case XFS_BTREE_TYPE_AG:
1094		*daddr = XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_ag.pag->pag_agno,
1095				be32_to_cpu(ptr->s));
1096		break;
1097	case XFS_BTREE_TYPE_INODE:
1098		*daddr = XFS_FSB_TO_DADDR(cur->bc_mp, be64_to_cpu(ptr->l));
1099		break;
1100	case XFS_BTREE_TYPE_MEM:
1101		*daddr = xfbno_to_daddr(be64_to_cpu(ptr->l));
1102		break;
1103	}
 
1104	return 0;
1105}
1106
1107/*
1108 * Readahead @count btree blocks at the given @ptr location.
1109 *
1110 * We don't need to care about long or short form btrees here as we have a
1111 * method of converting the ptr directly to a daddr available to us.
1112 */
1113STATIC void
1114xfs_btree_readahead_ptr(
1115	struct xfs_btree_cur	*cur,
1116	union xfs_btree_ptr	*ptr,
1117	xfs_extlen_t		count)
1118{
1119	xfs_daddr_t		daddr;
1120
1121	if (xfs_btree_ptr_to_daddr(cur, ptr, &daddr))
1122		return;
1123	xfs_buf_readahead(xfs_btree_buftarg(cur), daddr,
1124			xfs_btree_bbsize(cur) * count,
1125			cur->bc_ops->buf_ops);
1126}
1127
1128/*
1129 * Set the buffer for level "lev" in the cursor to bp, releasing
1130 * any previous buffer.
1131 */
1132STATIC void
1133xfs_btree_setbuf(
1134	struct xfs_btree_cur	*cur,	/* btree cursor */
1135	int			lev,	/* level in btree */
1136	struct xfs_buf		*bp)	/* new buffer to set */
1137{
1138	struct xfs_btree_block	*b;	/* btree block */
1139
1140	if (cur->bc_levels[lev].bp)
1141		xfs_trans_brelse(cur->bc_tp, cur->bc_levels[lev].bp);
1142	cur->bc_levels[lev].bp = bp;
1143	cur->bc_levels[lev].ra = 0;
1144
1145	b = XFS_BUF_TO_BLOCK(bp);
1146	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1147		if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK))
1148			cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1149		if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK))
1150			cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1151	} else {
1152		if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
1153			cur->bc_levels[lev].ra |= XFS_BTCUR_LEFTRA;
1154		if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
1155			cur->bc_levels[lev].ra |= XFS_BTCUR_RIGHTRA;
1156	}
1157}
1158
1159bool
1160xfs_btree_ptr_is_null(
1161	struct xfs_btree_cur		*cur,
1162	const union xfs_btree_ptr	*ptr)
1163{
1164	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
1165		return ptr->l == cpu_to_be64(NULLFSBLOCK);
1166	else
1167		return ptr->s == cpu_to_be32(NULLAGBLOCK);
1168}
1169
1170void
1171xfs_btree_set_ptr_null(
1172	struct xfs_btree_cur	*cur,
1173	union xfs_btree_ptr	*ptr)
1174{
1175	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
1176		ptr->l = cpu_to_be64(NULLFSBLOCK);
1177	else
1178		ptr->s = cpu_to_be32(NULLAGBLOCK);
1179}
1180
1181static inline bool
1182xfs_btree_ptrs_equal(
1183	struct xfs_btree_cur		*cur,
1184	union xfs_btree_ptr		*ptr1,
1185	union xfs_btree_ptr		*ptr2)
1186{
1187	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
1188		return ptr1->l == ptr2->l;
1189	return ptr1->s == ptr2->s;
1190}
1191
1192/*
1193 * Get/set/init sibling pointers
1194 */
1195void
1196xfs_btree_get_sibling(
1197	struct xfs_btree_cur	*cur,
1198	struct xfs_btree_block	*block,
1199	union xfs_btree_ptr	*ptr,
1200	int			lr)
1201{
1202	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1203
1204	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1205		if (lr == XFS_BB_RIGHTSIB)
1206			ptr->l = block->bb_u.l.bb_rightsib;
1207		else
1208			ptr->l = block->bb_u.l.bb_leftsib;
1209	} else {
1210		if (lr == XFS_BB_RIGHTSIB)
1211			ptr->s = block->bb_u.s.bb_rightsib;
1212		else
1213			ptr->s = block->bb_u.s.bb_leftsib;
1214	}
1215}
1216
1217void
1218xfs_btree_set_sibling(
1219	struct xfs_btree_cur		*cur,
1220	struct xfs_btree_block		*block,
1221	const union xfs_btree_ptr	*ptr,
1222	int				lr)
1223{
1224	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1225
1226	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1227		if (lr == XFS_BB_RIGHTSIB)
1228			block->bb_u.l.bb_rightsib = ptr->l;
1229		else
1230			block->bb_u.l.bb_leftsib = ptr->l;
1231	} else {
1232		if (lr == XFS_BB_RIGHTSIB)
1233			block->bb_u.s.bb_rightsib = ptr->s;
1234		else
1235			block->bb_u.s.bb_leftsib = ptr->s;
1236	}
1237}
1238
1239static void
1240__xfs_btree_init_block(
1241	struct xfs_mount	*mp,
1242	struct xfs_btree_block	*buf,
1243	const struct xfs_btree_ops *ops,
1244	xfs_daddr_t		blkno,
 
1245	__u16			level,
1246	__u16			numrecs,
1247	__u64			owner)
 
1248{
1249	bool			crc = xfs_has_crc(mp);
1250	__u32			magic = xfs_btree_magic(mp, ops);
1251
1252	buf->bb_magic = cpu_to_be32(magic);
1253	buf->bb_level = cpu_to_be16(level);
1254	buf->bb_numrecs = cpu_to_be16(numrecs);
1255
1256	if (ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1257		buf->bb_u.l.bb_leftsib = cpu_to_be64(NULLFSBLOCK);
1258		buf->bb_u.l.bb_rightsib = cpu_to_be64(NULLFSBLOCK);
1259		if (crc) {
1260			buf->bb_u.l.bb_blkno = cpu_to_be64(blkno);
1261			buf->bb_u.l.bb_owner = cpu_to_be64(owner);
1262			uuid_copy(&buf->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid);
1263			buf->bb_u.l.bb_pad = 0;
1264			buf->bb_u.l.bb_lsn = 0;
1265		}
1266	} else {
 
 
 
1267		buf->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
1268		buf->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
1269		if (crc) {
1270			buf->bb_u.s.bb_blkno = cpu_to_be64(blkno);
1271			/* owner is a 32 bit value on short blocks */
1272			buf->bb_u.s.bb_owner = cpu_to_be32((__u32)owner);
1273			uuid_copy(&buf->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid);
1274			buf->bb_u.s.bb_lsn = 0;
1275		}
1276	}
1277}
1278
1279void
1280xfs_btree_init_block(
1281	struct xfs_mount	*mp,
1282	struct xfs_btree_block	*block,
1283	const struct xfs_btree_ops *ops,
1284	__u16			level,
1285	__u16			numrecs,
1286	__u64			owner)
1287{
1288	__xfs_btree_init_block(mp, block, ops, XFS_BUF_DADDR_NULL, level,
1289			numrecs, owner);
1290}
1291
1292void
1293xfs_btree_init_buf(
1294	struct xfs_mount		*mp,
1295	struct xfs_buf			*bp,
1296	const struct xfs_btree_ops	*ops,
1297	__u16				level,
1298	__u16				numrecs,
1299	__u64				owner)
1300{
1301	__xfs_btree_init_block(mp, XFS_BUF_TO_BLOCK(bp), ops,
1302			xfs_buf_daddr(bp), level, numrecs, owner);
1303	bp->b_ops = ops->buf_ops;
1304}
1305
1306static inline __u64
1307xfs_btree_owner(
1308	struct xfs_btree_cur    *cur)
1309{
1310	switch (cur->bc_ops->type) {
1311	case XFS_BTREE_TYPE_MEM:
1312		return cur->bc_mem.xfbtree->owner;
1313	case XFS_BTREE_TYPE_INODE:
1314		return cur->bc_ino.ip->i_ino;
1315	case XFS_BTREE_TYPE_AG:
1316		return cur->bc_ag.pag->pag_agno;
1317	default:
1318		ASSERT(0);
1319		return 0;
1320	}
1321}
1322
1323void
1324xfs_btree_init_block_cur(
1325	struct xfs_btree_cur	*cur,
1326	struct xfs_buf		*bp,
1327	int			level,
1328	int			numrecs)
1329{
1330	xfs_btree_init_buf(cur->bc_mp, bp, cur->bc_ops, level, numrecs,
1331			xfs_btree_owner(cur));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1332}
1333
1334/*
1335 * Return true if ptr is the last record in the btree and
1336 * we need to track updates to this record.  The decision
1337 * will be further refined in the update_lastrec method.
1338 */
1339STATIC int
1340xfs_btree_is_lastrec(
1341	struct xfs_btree_cur	*cur,
1342	struct xfs_btree_block	*block,
1343	int			level)
1344{
1345	union xfs_btree_ptr	ptr;
1346
1347	if (level > 0)
1348		return 0;
1349	if (!(cur->bc_ops->geom_flags & XFS_BTGEO_LASTREC_UPDATE))
1350		return 0;
1351
1352	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1353	if (!xfs_btree_ptr_is_null(cur, &ptr))
1354		return 0;
1355	return 1;
1356}
1357
1358STATIC void
1359xfs_btree_buf_to_ptr(
1360	struct xfs_btree_cur	*cur,
1361	struct xfs_buf		*bp,
1362	union xfs_btree_ptr	*ptr)
1363{
1364	switch (cur->bc_ops->type) {
1365	case XFS_BTREE_TYPE_AG:
1366		ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
1367					xfs_buf_daddr(bp)));
1368		break;
1369	case XFS_BTREE_TYPE_INODE:
1370		ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
1371					xfs_buf_daddr(bp)));
1372		break;
1373	case XFS_BTREE_TYPE_MEM:
1374		ptr->l = cpu_to_be64(xfs_daddr_to_xfbno(xfs_buf_daddr(bp)));
1375		break;
1376	}
1377}
1378
1379static inline void
1380xfs_btree_set_refs(
1381	struct xfs_btree_cur	*cur,
1382	struct xfs_buf		*bp)
1383{
1384	xfs_buf_set_ref(bp, cur->bc_ops->lru_refs);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1385}
1386
1387int
1388xfs_btree_get_buf_block(
1389	struct xfs_btree_cur		*cur,
1390	const union xfs_btree_ptr	*ptr,
1391	struct xfs_btree_block		**block,
1392	struct xfs_buf			**bpp)
1393{
1394	xfs_daddr_t			d;
1395	int				error;
 
1396
1397	error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1398	if (error)
1399		return error;
1400	error = xfs_trans_get_buf(cur->bc_tp, xfs_btree_buftarg(cur), d,
1401			xfs_btree_bbsize(cur), 0, bpp);
1402	if (error)
1403		return error;
 
1404
1405	(*bpp)->b_ops = cur->bc_ops->buf_ops;
1406	*block = XFS_BUF_TO_BLOCK(*bpp);
1407	return 0;
1408}
1409
1410/*
1411 * Read in the buffer at the given ptr and return the buffer and
1412 * the block pointer within the buffer.
1413 */
1414int
1415xfs_btree_read_buf_block(
1416	struct xfs_btree_cur		*cur,
1417	const union xfs_btree_ptr	*ptr,
1418	int				flags,
1419	struct xfs_btree_block		**block,
1420	struct xfs_buf			**bpp)
1421{
1422	struct xfs_mount	*mp = cur->bc_mp;
1423	xfs_daddr_t		d;
1424	int			error;
1425
1426	/* need to sort out how callers deal with failures first */
1427	ASSERT(!(flags & XBF_TRYLOCK));
1428
1429	error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1430	if (error)
1431		return error;
1432	error = xfs_trans_read_buf(mp, cur->bc_tp, xfs_btree_buftarg(cur), d,
1433			xfs_btree_bbsize(cur), flags, bpp,
1434			cur->bc_ops->buf_ops);
1435	if (xfs_metadata_is_sick(error))
1436		xfs_btree_mark_sick(cur);
1437	if (error)
1438		return error;
1439
1440	xfs_btree_set_refs(cur, *bpp);
1441	*block = XFS_BUF_TO_BLOCK(*bpp);
1442	return 0;
1443}
1444
1445/*
1446 * Copy keys from one btree block to another.
1447 */
1448void
1449xfs_btree_copy_keys(
1450	struct xfs_btree_cur		*cur,
1451	union xfs_btree_key		*dst_key,
1452	const union xfs_btree_key	*src_key,
1453	int				numkeys)
1454{
1455	ASSERT(numkeys >= 0);
1456	memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1457}
1458
1459/*
1460 * Copy records from one btree block to another.
1461 */
1462STATIC void
1463xfs_btree_copy_recs(
1464	struct xfs_btree_cur	*cur,
1465	union xfs_btree_rec	*dst_rec,
1466	union xfs_btree_rec	*src_rec,
1467	int			numrecs)
1468{
1469	ASSERT(numrecs >= 0);
1470	memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1471}
1472
1473/*
1474 * Copy block pointers from one btree block to another.
1475 */
1476void
1477xfs_btree_copy_ptrs(
1478	struct xfs_btree_cur	*cur,
1479	union xfs_btree_ptr	*dst_ptr,
1480	const union xfs_btree_ptr *src_ptr,
1481	int			numptrs)
1482{
1483	ASSERT(numptrs >= 0);
1484	memcpy(dst_ptr, src_ptr, numptrs * cur->bc_ops->ptr_len);
1485}
1486
1487/*
1488 * Shift keys one index left/right inside a single btree block.
1489 */
1490STATIC void
1491xfs_btree_shift_keys(
1492	struct xfs_btree_cur	*cur,
1493	union xfs_btree_key	*key,
1494	int			dir,
1495	int			numkeys)
1496{
1497	char			*dst_key;
1498
1499	ASSERT(numkeys >= 0);
1500	ASSERT(dir == 1 || dir == -1);
1501
1502	dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1503	memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1504}
1505
1506/*
1507 * Shift records one index left/right inside a single btree block.
1508 */
1509STATIC void
1510xfs_btree_shift_recs(
1511	struct xfs_btree_cur	*cur,
1512	union xfs_btree_rec	*rec,
1513	int			dir,
1514	int			numrecs)
1515{
1516	char			*dst_rec;
1517
1518	ASSERT(numrecs >= 0);
1519	ASSERT(dir == 1 || dir == -1);
1520
1521	dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1522	memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1523}
1524
1525/*
1526 * Shift block pointers one index left/right inside a single btree block.
1527 */
1528STATIC void
1529xfs_btree_shift_ptrs(
1530	struct xfs_btree_cur	*cur,
1531	union xfs_btree_ptr	*ptr,
1532	int			dir,
1533	int			numptrs)
1534{
1535	char			*dst_ptr;
1536
1537	ASSERT(numptrs >= 0);
1538	ASSERT(dir == 1 || dir == -1);
1539
1540	dst_ptr = (char *)ptr + (dir * cur->bc_ops->ptr_len);
1541	memmove(dst_ptr, ptr, numptrs * cur->bc_ops->ptr_len);
1542}
1543
1544/*
1545 * Log key values from the btree block.
1546 */
1547STATIC void
1548xfs_btree_log_keys(
1549	struct xfs_btree_cur	*cur,
1550	struct xfs_buf		*bp,
1551	int			first,
1552	int			last)
1553{
1554
1555	if (bp) {
1556		xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1557		xfs_trans_log_buf(cur->bc_tp, bp,
1558				  xfs_btree_key_offset(cur, first),
1559				  xfs_btree_key_offset(cur, last + 1) - 1);
1560	} else {
1561		xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1562				xfs_ilog_fbroot(cur->bc_ino.whichfork));
1563	}
1564}
1565
1566/*
1567 * Log record values from the btree block.
1568 */
1569void
1570xfs_btree_log_recs(
1571	struct xfs_btree_cur	*cur,
1572	struct xfs_buf		*bp,
1573	int			first,
1574	int			last)
1575{
1576
1577	xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1578	xfs_trans_log_buf(cur->bc_tp, bp,
1579			  xfs_btree_rec_offset(cur, first),
1580			  xfs_btree_rec_offset(cur, last + 1) - 1);
1581
1582}
1583
1584/*
1585 * Log block pointer fields from a btree block (nonleaf).
1586 */
1587STATIC void
1588xfs_btree_log_ptrs(
1589	struct xfs_btree_cur	*cur,	/* btree cursor */
1590	struct xfs_buf		*bp,	/* buffer containing btree block */
1591	int			first,	/* index of first pointer to log */
1592	int			last)	/* index of last pointer to log */
1593{
1594
1595	if (bp) {
1596		struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
1597		int			level = xfs_btree_get_level(block);
1598
1599		xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1600		xfs_trans_log_buf(cur->bc_tp, bp,
1601				xfs_btree_ptr_offset(cur, first, level),
1602				xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1603	} else {
1604		xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1605			xfs_ilog_fbroot(cur->bc_ino.whichfork));
1606	}
1607
1608}
1609
1610/*
1611 * Log fields from a btree block header.
1612 */
1613void
1614xfs_btree_log_block(
1615	struct xfs_btree_cur	*cur,	/* btree cursor */
1616	struct xfs_buf		*bp,	/* buffer containing btree block */
1617	uint32_t		fields)	/* mask of fields: XFS_BB_... */
1618{
1619	int			first;	/* first byte offset logged */
1620	int			last;	/* last byte offset logged */
1621	static const short	soffsets[] = {	/* table of offsets (short) */
1622		offsetof(struct xfs_btree_block, bb_magic),
1623		offsetof(struct xfs_btree_block, bb_level),
1624		offsetof(struct xfs_btree_block, bb_numrecs),
1625		offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1626		offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1627		offsetof(struct xfs_btree_block, bb_u.s.bb_blkno),
1628		offsetof(struct xfs_btree_block, bb_u.s.bb_lsn),
1629		offsetof(struct xfs_btree_block, bb_u.s.bb_uuid),
1630		offsetof(struct xfs_btree_block, bb_u.s.bb_owner),
1631		offsetof(struct xfs_btree_block, bb_u.s.bb_crc),
1632		XFS_BTREE_SBLOCK_CRC_LEN
1633	};
1634	static const short	loffsets[] = {	/* table of offsets (long) */
1635		offsetof(struct xfs_btree_block, bb_magic),
1636		offsetof(struct xfs_btree_block, bb_level),
1637		offsetof(struct xfs_btree_block, bb_numrecs),
1638		offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1639		offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1640		offsetof(struct xfs_btree_block, bb_u.l.bb_blkno),
1641		offsetof(struct xfs_btree_block, bb_u.l.bb_lsn),
1642		offsetof(struct xfs_btree_block, bb_u.l.bb_uuid),
1643		offsetof(struct xfs_btree_block, bb_u.l.bb_owner),
1644		offsetof(struct xfs_btree_block, bb_u.l.bb_crc),
1645		offsetof(struct xfs_btree_block, bb_u.l.bb_pad),
1646		XFS_BTREE_LBLOCK_CRC_LEN
1647	};
1648
1649	if (bp) {
1650		int nbits;
1651
1652		if (xfs_has_crc(cur->bc_mp)) {
1653			/*
1654			 * We don't log the CRC when updating a btree
1655			 * block but instead recreate it during log
1656			 * recovery.  As the log buffers have checksums
1657			 * of their own this is safe and avoids logging a crc
1658			 * update in a lot of places.
1659			 */
1660			if (fields == XFS_BB_ALL_BITS)
1661				fields = XFS_BB_ALL_BITS_CRC;
1662			nbits = XFS_BB_NUM_BITS_CRC;
1663		} else {
1664			nbits = XFS_BB_NUM_BITS;
1665		}
1666		xfs_btree_offsets(fields,
1667				  (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) ?
1668					loffsets : soffsets,
1669				  nbits, &first, &last);
1670		xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1671		xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1672	} else {
1673		xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1674			xfs_ilog_fbroot(cur->bc_ino.whichfork));
1675	}
1676}
1677
1678/*
1679 * Increment cursor by one record at the level.
1680 * For nonzero levels the leaf-ward information is untouched.
1681 */
1682int						/* error */
1683xfs_btree_increment(
1684	struct xfs_btree_cur	*cur,
1685	int			level,
1686	int			*stat)		/* success/failure */
1687{
1688	struct xfs_btree_block	*block;
1689	union xfs_btree_ptr	ptr;
1690	struct xfs_buf		*bp;
1691	int			error;		/* error return value */
1692	int			lev;
1693
1694	ASSERT(level < cur->bc_nlevels);
1695
1696	/* Read-ahead to the right at this level. */
1697	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1698
1699	/* Get a pointer to the btree block. */
1700	block = xfs_btree_get_block(cur, level, &bp);
1701
1702#ifdef DEBUG
1703	error = xfs_btree_check_block(cur, block, level, bp);
1704	if (error)
1705		goto error0;
1706#endif
1707
1708	/* We're done if we remain in the block after the increment. */
1709	if (++cur->bc_levels[level].ptr <= xfs_btree_get_numrecs(block))
1710		goto out1;
1711
1712	/* Fail if we just went off the right edge of the tree. */
1713	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1714	if (xfs_btree_ptr_is_null(cur, &ptr))
1715		goto out0;
1716
1717	XFS_BTREE_STATS_INC(cur, increment);
1718
1719	/*
1720	 * March up the tree incrementing pointers.
1721	 * Stop when we don't go off the right edge of a block.
1722	 */
1723	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1724		block = xfs_btree_get_block(cur, lev, &bp);
1725
1726#ifdef DEBUG
1727		error = xfs_btree_check_block(cur, block, lev, bp);
1728		if (error)
1729			goto error0;
1730#endif
1731
1732		if (++cur->bc_levels[lev].ptr <= xfs_btree_get_numrecs(block))
1733			break;
1734
1735		/* Read-ahead the right block for the next loop. */
1736		xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1737	}
1738
1739	/*
1740	 * If we went off the root then we are either seriously
1741	 * confused or have the tree root in an inode.
1742	 */
1743	if (lev == cur->bc_nlevels) {
1744		if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE)
1745			goto out0;
1746		ASSERT(0);
1747		xfs_btree_mark_sick(cur);
1748		error = -EFSCORRUPTED;
1749		goto error0;
1750	}
1751	ASSERT(lev < cur->bc_nlevels);
1752
1753	/*
1754	 * Now walk back down the tree, fixing up the cursor's buffer
1755	 * pointers and key numbers.
1756	 */
1757	for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1758		union xfs_btree_ptr	*ptrp;
1759
1760		ptrp = xfs_btree_ptr_addr(cur, cur->bc_levels[lev].ptr, block);
1761		--lev;
1762		error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1763		if (error)
1764			goto error0;
1765
1766		xfs_btree_setbuf(cur, lev, bp);
1767		cur->bc_levels[lev].ptr = 1;
1768	}
1769out1:
1770	*stat = 1;
1771	return 0;
1772
1773out0:
1774	*stat = 0;
1775	return 0;
1776
1777error0:
1778	return error;
1779}
1780
1781/*
1782 * Decrement cursor by one record at the level.
1783 * For nonzero levels the leaf-ward information is untouched.
1784 */
1785int						/* error */
1786xfs_btree_decrement(
1787	struct xfs_btree_cur	*cur,
1788	int			level,
1789	int			*stat)		/* success/failure */
1790{
1791	struct xfs_btree_block	*block;
1792	struct xfs_buf		*bp;
1793	int			error;		/* error return value */
1794	int			lev;
1795	union xfs_btree_ptr	ptr;
1796
1797	ASSERT(level < cur->bc_nlevels);
1798
1799	/* Read-ahead to the left at this level. */
1800	xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1801
1802	/* We're done if we remain in the block after the decrement. */
1803	if (--cur->bc_levels[level].ptr > 0)
1804		goto out1;
1805
1806	/* Get a pointer to the btree block. */
1807	block = xfs_btree_get_block(cur, level, &bp);
1808
1809#ifdef DEBUG
1810	error = xfs_btree_check_block(cur, block, level, bp);
1811	if (error)
1812		goto error0;
1813#endif
1814
1815	/* Fail if we just went off the left edge of the tree. */
1816	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1817	if (xfs_btree_ptr_is_null(cur, &ptr))
1818		goto out0;
1819
1820	XFS_BTREE_STATS_INC(cur, decrement);
1821
1822	/*
1823	 * March up the tree decrementing pointers.
1824	 * Stop when we don't go off the left edge of a block.
1825	 */
1826	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1827		if (--cur->bc_levels[lev].ptr > 0)
1828			break;
1829		/* Read-ahead the left block for the next loop. */
1830		xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1831	}
1832
1833	/*
1834	 * If we went off the root then we are seriously confused.
1835	 * or the root of the tree is in an inode.
1836	 */
1837	if (lev == cur->bc_nlevels) {
1838		if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE)
1839			goto out0;
1840		ASSERT(0);
1841		xfs_btree_mark_sick(cur);
1842		error = -EFSCORRUPTED;
1843		goto error0;
1844	}
1845	ASSERT(lev < cur->bc_nlevels);
1846
1847	/*
1848	 * Now walk back down the tree, fixing up the cursor's buffer
1849	 * pointers and key numbers.
1850	 */
1851	for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1852		union xfs_btree_ptr	*ptrp;
1853
1854		ptrp = xfs_btree_ptr_addr(cur, cur->bc_levels[lev].ptr, block);
1855		--lev;
1856		error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1857		if (error)
1858			goto error0;
1859		xfs_btree_setbuf(cur, lev, bp);
1860		cur->bc_levels[lev].ptr = xfs_btree_get_numrecs(block);
1861	}
1862out1:
1863	*stat = 1;
1864	return 0;
1865
1866out0:
1867	*stat = 0;
1868	return 0;
1869
1870error0:
1871	return error;
1872}
1873
1874/*
1875 * Check the btree block owner now that we have the context to know who the
1876 * real owner is.
1877 */
1878static inline xfs_failaddr_t
1879xfs_btree_check_block_owner(
1880	struct xfs_btree_cur	*cur,
1881	struct xfs_btree_block	*block)
1882{
1883	__u64			owner;
1884
1885	if (!xfs_has_crc(cur->bc_mp) ||
1886	    (cur->bc_flags & XFS_BTREE_BMBT_INVALID_OWNER))
1887		return NULL;
1888
1889	owner = xfs_btree_owner(cur);
1890	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
1891		if (be64_to_cpu(block->bb_u.l.bb_owner) != owner)
1892			return __this_address;
1893	} else {
1894		if (be32_to_cpu(block->bb_u.s.bb_owner) != owner)
1895			return __this_address;
1896	}
1897
1898	return NULL;
1899}
1900
1901int
1902xfs_btree_lookup_get_block(
1903	struct xfs_btree_cur		*cur,	/* btree cursor */
1904	int				level,	/* level in the btree */
1905	const union xfs_btree_ptr	*pp,	/* ptr to btree block */
1906	struct xfs_btree_block		**blkp) /* return btree block */
1907{
1908	struct xfs_buf		*bp;	/* buffer pointer for btree block */
1909	xfs_daddr_t		daddr;
1910	int			error = 0;
1911
1912	/* special case the root block if in an inode */
1913	if (xfs_btree_at_iroot(cur, level)) {
 
1914		*blkp = xfs_btree_get_iroot(cur);
1915		return 0;
1916	}
1917
1918	/*
1919	 * If the old buffer at this level for the disk address we are
1920	 * looking for re-use it.
1921	 *
1922	 * Otherwise throw it away and get a new one.
1923	 */
1924	bp = cur->bc_levels[level].bp;
1925	error = xfs_btree_ptr_to_daddr(cur, pp, &daddr);
1926	if (error)
1927		return error;
1928	if (bp && xfs_buf_daddr(bp) == daddr) {
1929		*blkp = XFS_BUF_TO_BLOCK(bp);
1930		return 0;
1931	}
1932
1933	error = xfs_btree_read_buf_block(cur, pp, 0, blkp, &bp);
1934	if (error)
1935		return error;
1936
1937	/* Check the inode owner since the verifiers don't. */
1938	if (xfs_btree_check_block_owner(cur, *blkp) != NULL)
 
 
 
 
1939		goto out_bad;
1940
1941	/* Did we get the level we were looking for? */
1942	if (be16_to_cpu((*blkp)->bb_level) != level)
1943		goto out_bad;
1944
1945	/* Check that internal nodes have at least one record. */
1946	if (level != 0 && be16_to_cpu((*blkp)->bb_numrecs) == 0)
1947		goto out_bad;
1948
1949	xfs_btree_setbuf(cur, level, bp);
1950	return 0;
1951
1952out_bad:
1953	*blkp = NULL;
1954	xfs_buf_mark_corrupt(bp);
1955	xfs_trans_brelse(cur->bc_tp, bp);
1956	xfs_btree_mark_sick(cur);
1957	return -EFSCORRUPTED;
1958}
1959
1960/*
1961 * Get current search key.  For level 0 we don't actually have a key
1962 * structure so we make one up from the record.  For all other levels
1963 * we just return the right key.
1964 */
1965STATIC union xfs_btree_key *
1966xfs_lookup_get_search_key(
1967	struct xfs_btree_cur	*cur,
1968	int			level,
1969	int			keyno,
1970	struct xfs_btree_block	*block,
1971	union xfs_btree_key	*kp)
1972{
1973	if (level == 0) {
1974		cur->bc_ops->init_key_from_rec(kp,
1975				xfs_btree_rec_addr(cur, keyno, block));
1976		return kp;
1977	}
1978
1979	return xfs_btree_key_addr(cur, keyno, block);
1980}
1981
1982/*
1983 * Initialize a pointer to the root block.
1984 */
1985void
1986xfs_btree_init_ptr_from_cur(
1987	struct xfs_btree_cur	*cur,
1988	union xfs_btree_ptr	*ptr)
1989{
1990	if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE) {
1991		/*
1992		 * Inode-rooted btrees call xfs_btree_get_iroot to find the root
1993		 * in xfs_btree_lookup_get_block and don't need a pointer here.
1994		 */
1995		ptr->l = 0;
1996	} else if (cur->bc_flags & XFS_BTREE_STAGING) {
1997		ptr->s = cpu_to_be32(cur->bc_ag.afake->af_root);
1998	} else {
1999		cur->bc_ops->init_ptr_from_cur(cur, ptr);
2000	}
2001}
2002
2003/*
2004 * Lookup the record.  The cursor is made to point to it, based on dir.
2005 * stat is set to 0 if can't find any such record, 1 for success.
2006 */
2007int					/* error */
2008xfs_btree_lookup(
2009	struct xfs_btree_cur	*cur,	/* btree cursor */
2010	xfs_lookup_t		dir,	/* <=, ==, or >= */
2011	int			*stat)	/* success/failure */
2012{
2013	struct xfs_btree_block	*block;	/* current btree block */
2014	int64_t			diff;	/* difference for the current key */
2015	int			error;	/* error return value */
2016	int			keyno;	/* current key number */
2017	int			level;	/* level in the btree */
2018	union xfs_btree_ptr	*pp;	/* ptr to btree block */
2019	union xfs_btree_ptr	ptr;	/* ptr to btree block */
2020
2021	XFS_BTREE_STATS_INC(cur, lookup);
2022
2023	/* No such thing as a zero-level tree. */
2024	if (XFS_IS_CORRUPT(cur->bc_mp, cur->bc_nlevels == 0)) {
2025		xfs_btree_mark_sick(cur);
2026		return -EFSCORRUPTED;
2027	}
2028
2029	block = NULL;
2030	keyno = 0;
2031
2032	/* initialise start pointer from cursor */
2033	xfs_btree_init_ptr_from_cur(cur, &ptr);
2034	pp = &ptr;
2035
2036	/*
2037	 * Iterate over each level in the btree, starting at the root.
2038	 * For each level above the leaves, find the key we need, based
2039	 * on the lookup record, then follow the corresponding block
2040	 * pointer down to the next level.
2041	 */
2042	for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
2043		/* Get the block we need to do the lookup on. */
2044		error = xfs_btree_lookup_get_block(cur, level, pp, &block);
2045		if (error)
2046			goto error0;
2047
2048		if (diff == 0) {
2049			/*
2050			 * If we already had a key match at a higher level, we
2051			 * know we need to use the first entry in this block.
2052			 */
2053			keyno = 1;
2054		} else {
2055			/* Otherwise search this block. Do a binary search. */
2056
2057			int	high;	/* high entry number */
2058			int	low;	/* low entry number */
2059
2060			/* Set low and high entry numbers, 1-based. */
2061			low = 1;
2062			high = xfs_btree_get_numrecs(block);
2063			if (!high) {
2064				/* Block is empty, must be an empty leaf. */
2065				if (level != 0 || cur->bc_nlevels != 1) {
2066					XFS_CORRUPTION_ERROR(__func__,
2067							XFS_ERRLEVEL_LOW,
2068							cur->bc_mp, block,
2069							sizeof(*block));
2070					xfs_btree_mark_sick(cur);
2071					return -EFSCORRUPTED;
2072				}
2073
2074				cur->bc_levels[0].ptr = dir != XFS_LOOKUP_LE;
2075				*stat = 0;
2076				return 0;
2077			}
2078
2079			/* Binary search the block. */
2080			while (low <= high) {
2081				union xfs_btree_key	key;
2082				union xfs_btree_key	*kp;
2083
2084				XFS_BTREE_STATS_INC(cur, compare);
2085
2086				/* keyno is average of low and high. */
2087				keyno = (low + high) >> 1;
2088
2089				/* Get current search key */
2090				kp = xfs_lookup_get_search_key(cur, level,
2091						keyno, block, &key);
2092
2093				/*
2094				 * Compute difference to get next direction:
2095				 *  - less than, move right
2096				 *  - greater than, move left
2097				 *  - equal, we're done
2098				 */
2099				diff = cur->bc_ops->key_diff(cur, kp);
2100				if (diff < 0)
2101					low = keyno + 1;
2102				else if (diff > 0)
2103					high = keyno - 1;
2104				else
2105					break;
2106			}
2107		}
2108
2109		/*
2110		 * If there are more levels, set up for the next level
2111		 * by getting the block number and filling in the cursor.
2112		 */
2113		if (level > 0) {
2114			/*
2115			 * If we moved left, need the previous key number,
2116			 * unless there isn't one.
2117			 */
2118			if (diff > 0 && --keyno < 1)
2119				keyno = 1;
2120			pp = xfs_btree_ptr_addr(cur, keyno, block);
2121
2122			error = xfs_btree_debug_check_ptr(cur, pp, 0, level);
2123			if (error)
2124				goto error0;
2125
2126			cur->bc_levels[level].ptr = keyno;
2127		}
2128	}
2129
2130	/* Done with the search. See if we need to adjust the results. */
2131	if (dir != XFS_LOOKUP_LE && diff < 0) {
2132		keyno++;
2133		/*
2134		 * If ge search and we went off the end of the block, but it's
2135		 * not the last block, we're in the wrong block.
2136		 */
2137		xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
2138		if (dir == XFS_LOOKUP_GE &&
2139		    keyno > xfs_btree_get_numrecs(block) &&
2140		    !xfs_btree_ptr_is_null(cur, &ptr)) {
2141			int	i;
2142
2143			cur->bc_levels[0].ptr = keyno;
2144			error = xfs_btree_increment(cur, 0, &i);
2145			if (error)
2146				goto error0;
2147			if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
2148				xfs_btree_mark_sick(cur);
2149				return -EFSCORRUPTED;
2150			}
2151			*stat = 1;
2152			return 0;
2153		}
2154	} else if (dir == XFS_LOOKUP_LE && diff > 0)
2155		keyno--;
2156	cur->bc_levels[0].ptr = keyno;
2157
2158	/* Return if we succeeded or not. */
2159	if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
2160		*stat = 0;
2161	else if (dir != XFS_LOOKUP_EQ || diff == 0)
2162		*stat = 1;
2163	else
2164		*stat = 0;
2165	return 0;
2166
2167error0:
2168	return error;
2169}
2170
2171/* Find the high key storage area from a regular key. */
2172union xfs_btree_key *
2173xfs_btree_high_key_from_key(
2174	struct xfs_btree_cur	*cur,
2175	union xfs_btree_key	*key)
2176{
2177	ASSERT(cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING);
2178	return (union xfs_btree_key *)((char *)key +
2179			(cur->bc_ops->key_len / 2));
2180}
2181
2182/* Determine the low (and high if overlapped) keys of a leaf block */
2183STATIC void
2184xfs_btree_get_leaf_keys(
2185	struct xfs_btree_cur	*cur,
2186	struct xfs_btree_block	*block,
2187	union xfs_btree_key	*key)
2188{
2189	union xfs_btree_key	max_hkey;
2190	union xfs_btree_key	hkey;
2191	union xfs_btree_rec	*rec;
2192	union xfs_btree_key	*high;
2193	int			n;
2194
2195	rec = xfs_btree_rec_addr(cur, 1, block);
2196	cur->bc_ops->init_key_from_rec(key, rec);
2197
2198	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2199
2200		cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
2201		for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2202			rec = xfs_btree_rec_addr(cur, n, block);
2203			cur->bc_ops->init_high_key_from_rec(&hkey, rec);
2204			if (xfs_btree_keycmp_gt(cur, &hkey, &max_hkey))
 
2205				max_hkey = hkey;
2206		}
2207
2208		high = xfs_btree_high_key_from_key(cur, key);
2209		memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
2210	}
2211}
2212
2213/* Determine the low (and high if overlapped) keys of a node block */
2214STATIC void
2215xfs_btree_get_node_keys(
2216	struct xfs_btree_cur	*cur,
2217	struct xfs_btree_block	*block,
2218	union xfs_btree_key	*key)
2219{
2220	union xfs_btree_key	*hkey;
2221	union xfs_btree_key	*max_hkey;
2222	union xfs_btree_key	*high;
2223	int			n;
2224
2225	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2226		memcpy(key, xfs_btree_key_addr(cur, 1, block),
2227				cur->bc_ops->key_len / 2);
2228
2229		max_hkey = xfs_btree_high_key_addr(cur, 1, block);
2230		for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2231			hkey = xfs_btree_high_key_addr(cur, n, block);
2232			if (xfs_btree_keycmp_gt(cur, hkey, max_hkey))
2233				max_hkey = hkey;
2234		}
2235
2236		high = xfs_btree_high_key_from_key(cur, key);
2237		memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
2238	} else {
2239		memcpy(key, xfs_btree_key_addr(cur, 1, block),
2240				cur->bc_ops->key_len);
2241	}
2242}
2243
2244/* Derive the keys for any btree block. */
2245void
2246xfs_btree_get_keys(
2247	struct xfs_btree_cur	*cur,
2248	struct xfs_btree_block	*block,
2249	union xfs_btree_key	*key)
2250{
2251	if (be16_to_cpu(block->bb_level) == 0)
2252		xfs_btree_get_leaf_keys(cur, block, key);
2253	else
2254		xfs_btree_get_node_keys(cur, block, key);
2255}
2256
2257/*
2258 * Decide if we need to update the parent keys of a btree block.  For
2259 * a standard btree this is only necessary if we're updating the first
2260 * record/key.  For an overlapping btree, we must always update the
2261 * keys because the highest key can be in any of the records or keys
2262 * in the block.
2263 */
2264static inline bool
2265xfs_btree_needs_key_update(
2266	struct xfs_btree_cur	*cur,
2267	int			ptr)
2268{
2269	return (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) || ptr == 1;
2270}
2271
2272/*
2273 * Update the low and high parent keys of the given level, progressing
2274 * towards the root.  If force_all is false, stop if the keys for a given
2275 * level do not need updating.
2276 */
2277STATIC int
2278__xfs_btree_updkeys(
2279	struct xfs_btree_cur	*cur,
2280	int			level,
2281	struct xfs_btree_block	*block,
2282	struct xfs_buf		*bp0,
2283	bool			force_all)
2284{
2285	union xfs_btree_key	key;	/* keys from current level */
2286	union xfs_btree_key	*lkey;	/* keys from the next level up */
2287	union xfs_btree_key	*hkey;
2288	union xfs_btree_key	*nlkey;	/* keys from the next level up */
2289	union xfs_btree_key	*nhkey;
2290	struct xfs_buf		*bp;
2291	int			ptr;
2292
2293	ASSERT(cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING);
2294
2295	/* Exit if there aren't any parent levels to update. */
2296	if (level + 1 >= cur->bc_nlevels)
2297		return 0;
2298
2299	trace_xfs_btree_updkeys(cur, level, bp0);
2300
2301	lkey = &key;
2302	hkey = xfs_btree_high_key_from_key(cur, lkey);
2303	xfs_btree_get_keys(cur, block, lkey);
2304	for (level++; level < cur->bc_nlevels; level++) {
2305#ifdef DEBUG
2306		int		error;
2307#endif
2308		block = xfs_btree_get_block(cur, level, &bp);
2309		trace_xfs_btree_updkeys(cur, level, bp);
2310#ifdef DEBUG
2311		error = xfs_btree_check_block(cur, block, level, bp);
2312		if (error)
2313			return error;
2314#endif
2315		ptr = cur->bc_levels[level].ptr;
2316		nlkey = xfs_btree_key_addr(cur, ptr, block);
2317		nhkey = xfs_btree_high_key_addr(cur, ptr, block);
2318		if (!force_all &&
2319		    xfs_btree_keycmp_eq(cur, nlkey, lkey) &&
2320		    xfs_btree_keycmp_eq(cur, nhkey, hkey))
2321			break;
2322		xfs_btree_copy_keys(cur, nlkey, lkey, 1);
2323		xfs_btree_log_keys(cur, bp, ptr, ptr);
2324		if (level + 1 >= cur->bc_nlevels)
2325			break;
2326		xfs_btree_get_node_keys(cur, block, lkey);
2327	}
2328
2329	return 0;
2330}
2331
2332/* Update all the keys from some level in cursor back to the root. */
2333STATIC int
2334xfs_btree_updkeys_force(
2335	struct xfs_btree_cur	*cur,
2336	int			level)
2337{
2338	struct xfs_buf		*bp;
2339	struct xfs_btree_block	*block;
2340
2341	block = xfs_btree_get_block(cur, level, &bp);
2342	return __xfs_btree_updkeys(cur, level, block, bp, true);
2343}
2344
2345/*
2346 * Update the parent keys of the given level, progressing towards the root.
2347 */
2348STATIC int
2349xfs_btree_update_keys(
2350	struct xfs_btree_cur	*cur,
2351	int			level)
2352{
2353	struct xfs_btree_block	*block;
2354	struct xfs_buf		*bp;
2355	union xfs_btree_key	*kp;
2356	union xfs_btree_key	key;
2357	int			ptr;
2358
2359	ASSERT(level >= 0);
2360
2361	block = xfs_btree_get_block(cur, level, &bp);
2362	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING)
2363		return __xfs_btree_updkeys(cur, level, block, bp, false);
2364
2365	/*
2366	 * Go up the tree from this level toward the root.
2367	 * At each level, update the key value to the value input.
2368	 * Stop when we reach a level where the cursor isn't pointing
2369	 * at the first entry in the block.
2370	 */
2371	xfs_btree_get_keys(cur, block, &key);
2372	for (level++, ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
2373#ifdef DEBUG
2374		int		error;
2375#endif
2376		block = xfs_btree_get_block(cur, level, &bp);
2377#ifdef DEBUG
2378		error = xfs_btree_check_block(cur, block, level, bp);
2379		if (error)
2380			return error;
2381#endif
2382		ptr = cur->bc_levels[level].ptr;
2383		kp = xfs_btree_key_addr(cur, ptr, block);
2384		xfs_btree_copy_keys(cur, kp, &key, 1);
2385		xfs_btree_log_keys(cur, bp, ptr, ptr);
2386	}
2387
2388	return 0;
2389}
2390
2391/*
2392 * Update the record referred to by cur to the value in the
2393 * given record. This either works (return 0) or gets an
2394 * EFSCORRUPTED error.
2395 */
2396int
2397xfs_btree_update(
2398	struct xfs_btree_cur	*cur,
2399	union xfs_btree_rec	*rec)
2400{
2401	struct xfs_btree_block	*block;
2402	struct xfs_buf		*bp;
2403	int			error;
2404	int			ptr;
2405	union xfs_btree_rec	*rp;
2406
2407	/* Pick up the current block. */
2408	block = xfs_btree_get_block(cur, 0, &bp);
2409
2410#ifdef DEBUG
2411	error = xfs_btree_check_block(cur, block, 0, bp);
2412	if (error)
2413		goto error0;
2414#endif
2415	/* Get the address of the rec to be updated. */
2416	ptr = cur->bc_levels[0].ptr;
2417	rp = xfs_btree_rec_addr(cur, ptr, block);
2418
2419	/* Fill in the new contents and log them. */
2420	xfs_btree_copy_recs(cur, rp, rec, 1);
2421	xfs_btree_log_recs(cur, bp, ptr, ptr);
2422
2423	/*
2424	 * If we are tracking the last record in the tree and
2425	 * we are at the far right edge of the tree, update it.
2426	 */
2427	if (xfs_btree_is_lastrec(cur, block, 0)) {
2428		cur->bc_ops->update_lastrec(cur, block, rec,
2429					    ptr, LASTREC_UPDATE);
2430	}
2431
2432	/* Pass new key value up to our parent. */
2433	if (xfs_btree_needs_key_update(cur, ptr)) {
2434		error = xfs_btree_update_keys(cur, 0);
2435		if (error)
2436			goto error0;
2437	}
2438
2439	return 0;
2440
2441error0:
2442	return error;
2443}
2444
2445/*
2446 * Move 1 record left from cur/level if possible.
2447 * Update cur to reflect the new path.
2448 */
2449STATIC int					/* error */
2450xfs_btree_lshift(
2451	struct xfs_btree_cur	*cur,
2452	int			level,
2453	int			*stat)		/* success/failure */
2454{
2455	struct xfs_buf		*lbp;		/* left buffer pointer */
2456	struct xfs_btree_block	*left;		/* left btree block */
2457	int			lrecs;		/* left record count */
2458	struct xfs_buf		*rbp;		/* right buffer pointer */
2459	struct xfs_btree_block	*right;		/* right btree block */
2460	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
2461	int			rrecs;		/* right record count */
2462	union xfs_btree_ptr	lptr;		/* left btree pointer */
2463	union xfs_btree_key	*rkp = NULL;	/* right btree key */
2464	union xfs_btree_ptr	*rpp = NULL;	/* right address pointer */
2465	union xfs_btree_rec	*rrp = NULL;	/* right record pointer */
2466	int			error;		/* error return value */
2467	int			i;
2468
2469	if (xfs_btree_at_iroot(cur, level))
 
2470		goto out0;
2471
2472	/* Set up variables for this block as "right". */
2473	right = xfs_btree_get_block(cur, level, &rbp);
2474
2475#ifdef DEBUG
2476	error = xfs_btree_check_block(cur, right, level, rbp);
2477	if (error)
2478		goto error0;
2479#endif
2480
2481	/* If we've got no left sibling then we can't shift an entry left. */
2482	xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2483	if (xfs_btree_ptr_is_null(cur, &lptr))
2484		goto out0;
2485
2486	/*
2487	 * If the cursor entry is the one that would be moved, don't
2488	 * do it... it's too complicated.
2489	 */
2490	if (cur->bc_levels[level].ptr <= 1)
2491		goto out0;
2492
2493	/* Set up the left neighbor as "left". */
2494	error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
2495	if (error)
2496		goto error0;
2497
2498	/* If it's full, it can't take another entry. */
2499	lrecs = xfs_btree_get_numrecs(left);
2500	if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
2501		goto out0;
2502
2503	rrecs = xfs_btree_get_numrecs(right);
2504
2505	/*
2506	 * We add one entry to the left side and remove one for the right side.
2507	 * Account for it here, the changes will be updated on disk and logged
2508	 * later.
2509	 */
2510	lrecs++;
2511	rrecs--;
2512
2513	XFS_BTREE_STATS_INC(cur, lshift);
2514	XFS_BTREE_STATS_ADD(cur, moves, 1);
2515
2516	/*
2517	 * If non-leaf, copy a key and a ptr to the left block.
2518	 * Log the changes to the left block.
2519	 */
2520	if (level > 0) {
2521		/* It's a non-leaf.  Move keys and pointers. */
2522		union xfs_btree_key	*lkp;	/* left btree key */
2523		union xfs_btree_ptr	*lpp;	/* left address pointer */
2524
2525		lkp = xfs_btree_key_addr(cur, lrecs, left);
2526		rkp = xfs_btree_key_addr(cur, 1, right);
2527
2528		lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2529		rpp = xfs_btree_ptr_addr(cur, 1, right);
2530
2531		error = xfs_btree_debug_check_ptr(cur, rpp, 0, level);
2532		if (error)
2533			goto error0;
2534
2535		xfs_btree_copy_keys(cur, lkp, rkp, 1);
2536		xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
2537
2538		xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
2539		xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
2540
2541		ASSERT(cur->bc_ops->keys_inorder(cur,
2542			xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
2543	} else {
2544		/* It's a leaf.  Move records.  */
2545		union xfs_btree_rec	*lrp;	/* left record pointer */
2546
2547		lrp = xfs_btree_rec_addr(cur, lrecs, left);
2548		rrp = xfs_btree_rec_addr(cur, 1, right);
2549
2550		xfs_btree_copy_recs(cur, lrp, rrp, 1);
2551		xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
2552
2553		ASSERT(cur->bc_ops->recs_inorder(cur,
2554			xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
2555	}
2556
2557	xfs_btree_set_numrecs(left, lrecs);
2558	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2559
2560	xfs_btree_set_numrecs(right, rrecs);
2561	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2562
2563	/*
2564	 * Slide the contents of right down one entry.
2565	 */
2566	XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
2567	if (level > 0) {
2568		/* It's a nonleaf. operate on keys and ptrs */
 
 
2569		for (i = 0; i < rrecs; i++) {
2570			error = xfs_btree_debug_check_ptr(cur, rpp, i + 1, level);
2571			if (error)
2572				goto error0;
2573		}
2574
2575		xfs_btree_shift_keys(cur,
2576				xfs_btree_key_addr(cur, 2, right),
2577				-1, rrecs);
2578		xfs_btree_shift_ptrs(cur,
2579				xfs_btree_ptr_addr(cur, 2, right),
2580				-1, rrecs);
2581
2582		xfs_btree_log_keys(cur, rbp, 1, rrecs);
2583		xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2584	} else {
2585		/* It's a leaf. operate on records */
2586		xfs_btree_shift_recs(cur,
2587			xfs_btree_rec_addr(cur, 2, right),
2588			-1, rrecs);
2589		xfs_btree_log_recs(cur, rbp, 1, rrecs);
2590	}
2591
2592	/*
2593	 * Using a temporary cursor, update the parent key values of the
2594	 * block on the left.
2595	 */
2596	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2597		error = xfs_btree_dup_cursor(cur, &tcur);
2598		if (error)
2599			goto error0;
2600		i = xfs_btree_firstrec(tcur, level);
2601		if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2602			xfs_btree_mark_sick(cur);
2603			error = -EFSCORRUPTED;
2604			goto error0;
2605		}
2606
2607		error = xfs_btree_decrement(tcur, level, &i);
2608		if (error)
2609			goto error1;
2610
2611		/* Update the parent high keys of the left block, if needed. */
2612		error = xfs_btree_update_keys(tcur, level);
2613		if (error)
2614			goto error1;
2615
2616		xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2617	}
2618
2619	/* Update the parent keys of the right block. */
2620	error = xfs_btree_update_keys(cur, level);
2621	if (error)
2622		goto error0;
2623
2624	/* Slide the cursor value left one. */
2625	cur->bc_levels[level].ptr--;
2626
2627	*stat = 1;
2628	return 0;
2629
2630out0:
2631	*stat = 0;
2632	return 0;
2633
2634error0:
2635	return error;
2636
2637error1:
2638	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2639	return error;
2640}
2641
2642/*
2643 * Move 1 record right from cur/level if possible.
2644 * Update cur to reflect the new path.
2645 */
2646STATIC int					/* error */
2647xfs_btree_rshift(
2648	struct xfs_btree_cur	*cur,
2649	int			level,
2650	int			*stat)		/* success/failure */
2651{
2652	struct xfs_buf		*lbp;		/* left buffer pointer */
2653	struct xfs_btree_block	*left;		/* left btree block */
2654	struct xfs_buf		*rbp;		/* right buffer pointer */
2655	struct xfs_btree_block	*right;		/* right btree block */
2656	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
2657	union xfs_btree_ptr	rptr;		/* right block pointer */
2658	union xfs_btree_key	*rkp;		/* right btree key */
2659	int			rrecs;		/* right record count */
2660	int			lrecs;		/* left record count */
2661	int			error;		/* error return value */
2662	int			i;		/* loop counter */
2663
2664	if (xfs_btree_at_iroot(cur, level))
 
2665		goto out0;
2666
2667	/* Set up variables for this block as "left". */
2668	left = xfs_btree_get_block(cur, level, &lbp);
2669
2670#ifdef DEBUG
2671	error = xfs_btree_check_block(cur, left, level, lbp);
2672	if (error)
2673		goto error0;
2674#endif
2675
2676	/* If we've got no right sibling then we can't shift an entry right. */
2677	xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2678	if (xfs_btree_ptr_is_null(cur, &rptr))
2679		goto out0;
2680
2681	/*
2682	 * If the cursor entry is the one that would be moved, don't
2683	 * do it... it's too complicated.
2684	 */
2685	lrecs = xfs_btree_get_numrecs(left);
2686	if (cur->bc_levels[level].ptr >= lrecs)
2687		goto out0;
2688
2689	/* Set up the right neighbor as "right". */
2690	error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
2691	if (error)
2692		goto error0;
2693
2694	/* If it's full, it can't take another entry. */
2695	rrecs = xfs_btree_get_numrecs(right);
2696	if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2697		goto out0;
2698
2699	XFS_BTREE_STATS_INC(cur, rshift);
2700	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2701
2702	/*
2703	 * Make a hole at the start of the right neighbor block, then
2704	 * copy the last left block entry to the hole.
2705	 */
2706	if (level > 0) {
2707		/* It's a nonleaf. make a hole in the keys and ptrs */
2708		union xfs_btree_key	*lkp;
2709		union xfs_btree_ptr	*lpp;
2710		union xfs_btree_ptr	*rpp;
2711
2712		lkp = xfs_btree_key_addr(cur, lrecs, left);
2713		lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2714		rkp = xfs_btree_key_addr(cur, 1, right);
2715		rpp = xfs_btree_ptr_addr(cur, 1, right);
2716
2717		for (i = rrecs - 1; i >= 0; i--) {
2718			error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
2719			if (error)
2720				goto error0;
2721		}
2722
2723		xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2724		xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2725
2726		error = xfs_btree_debug_check_ptr(cur, lpp, 0, level);
2727		if (error)
2728			goto error0;
2729
2730		/* Now put the new data in, and log it. */
2731		xfs_btree_copy_keys(cur, rkp, lkp, 1);
2732		xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2733
2734		xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2735		xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2736
2737		ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2738			xfs_btree_key_addr(cur, 2, right)));
2739	} else {
2740		/* It's a leaf. make a hole in the records */
2741		union xfs_btree_rec	*lrp;
2742		union xfs_btree_rec	*rrp;
2743
2744		lrp = xfs_btree_rec_addr(cur, lrecs, left);
2745		rrp = xfs_btree_rec_addr(cur, 1, right);
2746
2747		xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2748
2749		/* Now put the new data in, and log it. */
2750		xfs_btree_copy_recs(cur, rrp, lrp, 1);
2751		xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2752	}
2753
2754	/*
2755	 * Decrement and log left's numrecs, bump and log right's numrecs.
2756	 */
2757	xfs_btree_set_numrecs(left, --lrecs);
2758	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2759
2760	xfs_btree_set_numrecs(right, ++rrecs);
2761	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2762
2763	/*
2764	 * Using a temporary cursor, update the parent key values of the
2765	 * block on the right.
2766	 */
2767	error = xfs_btree_dup_cursor(cur, &tcur);
2768	if (error)
2769		goto error0;
2770	i = xfs_btree_lastrec(tcur, level);
2771	if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2772		xfs_btree_mark_sick(cur);
2773		error = -EFSCORRUPTED;
2774		goto error0;
2775	}
2776
2777	error = xfs_btree_increment(tcur, level, &i);
2778	if (error)
2779		goto error1;
2780
2781	/* Update the parent high keys of the left block, if needed. */
2782	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2783		error = xfs_btree_update_keys(cur, level);
2784		if (error)
2785			goto error1;
2786	}
2787
2788	/* Update the parent keys of the right block. */
2789	error = xfs_btree_update_keys(tcur, level);
2790	if (error)
2791		goto error1;
2792
2793	xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2794
2795	*stat = 1;
2796	return 0;
2797
2798out0:
2799	*stat = 0;
2800	return 0;
2801
2802error0:
2803	return error;
2804
2805error1:
2806	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2807	return error;
2808}
2809
2810static inline int
2811xfs_btree_alloc_block(
2812	struct xfs_btree_cur		*cur,
2813	const union xfs_btree_ptr	*hint_block,
2814	union xfs_btree_ptr		*new_block,
2815	int				*stat)
2816{
2817	int				error;
2818
2819	/*
2820	 * Don't allow block allocation for a staging cursor, because staging
2821	 * cursors do not support regular btree modifications.
2822	 *
2823	 * Bulk loading uses a separate callback to obtain new blocks from a
2824	 * preallocated list, which prevents ENOSPC failures during loading.
2825	 */
2826	if (unlikely(cur->bc_flags & XFS_BTREE_STAGING)) {
2827		ASSERT(0);
2828		return -EFSCORRUPTED;
2829	}
2830
2831	error = cur->bc_ops->alloc_block(cur, hint_block, new_block, stat);
2832	trace_xfs_btree_alloc_block(cur, new_block, *stat, error);
2833	return error;
2834}
2835
2836/*
2837 * Split cur/level block in half.
2838 * Return new block number and the key to its first
2839 * record (to be inserted into parent).
2840 */
2841STATIC int					/* error */
2842__xfs_btree_split(
2843	struct xfs_btree_cur	*cur,
2844	int			level,
2845	union xfs_btree_ptr	*ptrp,
2846	union xfs_btree_key	*key,
2847	struct xfs_btree_cur	**curp,
2848	int			*stat)		/* success/failure */
2849{
2850	union xfs_btree_ptr	lptr;		/* left sibling block ptr */
2851	struct xfs_buf		*lbp;		/* left buffer pointer */
2852	struct xfs_btree_block	*left;		/* left btree block */
2853	union xfs_btree_ptr	rptr;		/* right sibling block ptr */
2854	struct xfs_buf		*rbp;		/* right buffer pointer */
2855	struct xfs_btree_block	*right;		/* right btree block */
2856	union xfs_btree_ptr	rrptr;		/* right-right sibling ptr */
2857	struct xfs_buf		*rrbp;		/* right-right buffer pointer */
2858	struct xfs_btree_block	*rrblock;	/* right-right btree block */
2859	int			lrecs;
2860	int			rrecs;
2861	int			src_index;
2862	int			error;		/* error return value */
2863	int			i;
2864
2865	XFS_BTREE_STATS_INC(cur, split);
2866
2867	/* Set up left block (current one). */
2868	left = xfs_btree_get_block(cur, level, &lbp);
2869
2870#ifdef DEBUG
2871	error = xfs_btree_check_block(cur, left, level, lbp);
2872	if (error)
2873		goto error0;
2874#endif
2875
2876	xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2877
2878	/* Allocate the new block. If we can't do it, we're toast. Give up. */
2879	error = xfs_btree_alloc_block(cur, &lptr, &rptr, stat);
2880	if (error)
2881		goto error0;
2882	if (*stat == 0)
2883		goto out0;
2884	XFS_BTREE_STATS_INC(cur, alloc);
2885
2886	/* Set up the new block as "right". */
2887	error = xfs_btree_get_buf_block(cur, &rptr, &right, &rbp);
2888	if (error)
2889		goto error0;
2890
2891	/* Fill in the btree header for the new right block. */
2892	xfs_btree_init_block_cur(cur, rbp, xfs_btree_get_level(left), 0);
2893
2894	/*
2895	 * Split the entries between the old and the new block evenly.
2896	 * Make sure that if there's an odd number of entries now, that
2897	 * each new block will have the same number of entries.
2898	 */
2899	lrecs = xfs_btree_get_numrecs(left);
2900	rrecs = lrecs / 2;
2901	if ((lrecs & 1) && cur->bc_levels[level].ptr <= rrecs + 1)
2902		rrecs++;
2903	src_index = (lrecs - rrecs + 1);
2904
2905	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2906
2907	/* Adjust numrecs for the later get_*_keys() calls. */
2908	lrecs -= rrecs;
2909	xfs_btree_set_numrecs(left, lrecs);
2910	xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2911
2912	/*
2913	 * Copy btree block entries from the left block over to the
2914	 * new block, the right. Update the right block and log the
2915	 * changes.
2916	 */
2917	if (level > 0) {
2918		/* It's a non-leaf.  Move keys and pointers. */
2919		union xfs_btree_key	*lkp;	/* left btree key */
2920		union xfs_btree_ptr	*lpp;	/* left address pointer */
2921		union xfs_btree_key	*rkp;	/* right btree key */
2922		union xfs_btree_ptr	*rpp;	/* right address pointer */
2923
2924		lkp = xfs_btree_key_addr(cur, src_index, left);
2925		lpp = xfs_btree_ptr_addr(cur, src_index, left);
2926		rkp = xfs_btree_key_addr(cur, 1, right);
2927		rpp = xfs_btree_ptr_addr(cur, 1, right);
2928
2929		for (i = src_index; i < rrecs; i++) {
2930			error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
2931			if (error)
2932				goto error0;
2933		}
2934
2935		/* Copy the keys & pointers to the new block. */
2936		xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2937		xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2938
2939		xfs_btree_log_keys(cur, rbp, 1, rrecs);
2940		xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2941
2942		/* Stash the keys of the new block for later insertion. */
2943		xfs_btree_get_node_keys(cur, right, key);
2944	} else {
2945		/* It's a leaf.  Move records.  */
2946		union xfs_btree_rec	*lrp;	/* left record pointer */
2947		union xfs_btree_rec	*rrp;	/* right record pointer */
2948
2949		lrp = xfs_btree_rec_addr(cur, src_index, left);
2950		rrp = xfs_btree_rec_addr(cur, 1, right);
2951
2952		/* Copy records to the new block. */
2953		xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2954		xfs_btree_log_recs(cur, rbp, 1, rrecs);
2955
2956		/* Stash the keys of the new block for later insertion. */
2957		xfs_btree_get_leaf_keys(cur, right, key);
2958	}
2959
2960	/*
2961	 * Find the left block number by looking in the buffer.
2962	 * Adjust sibling pointers.
2963	 */
2964	xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2965	xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2966	xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2967	xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2968
2969	xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2970	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2971
2972	/*
2973	 * If there's a block to the new block's right, make that block
2974	 * point back to right instead of to left.
2975	 */
2976	if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2977		error = xfs_btree_read_buf_block(cur, &rrptr,
2978							0, &rrblock, &rrbp);
2979		if (error)
2980			goto error0;
2981		xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2982		xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2983	}
2984
2985	/* Update the parent high keys of the left block, if needed. */
2986	if (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING) {
2987		error = xfs_btree_update_keys(cur, level);
2988		if (error)
2989			goto error0;
2990	}
2991
2992	/*
2993	 * If the cursor is really in the right block, move it there.
2994	 * If it's just pointing past the last entry in left, then we'll
2995	 * insert there, so don't change anything in that case.
2996	 */
2997	if (cur->bc_levels[level].ptr > lrecs + 1) {
2998		xfs_btree_setbuf(cur, level, rbp);
2999		cur->bc_levels[level].ptr -= lrecs;
3000	}
3001	/*
3002	 * If there are more levels, we'll need another cursor which refers
3003	 * the right block, no matter where this cursor was.
3004	 */
3005	if (level + 1 < cur->bc_nlevels) {
3006		error = xfs_btree_dup_cursor(cur, curp);
3007		if (error)
3008			goto error0;
3009		(*curp)->bc_levels[level + 1].ptr++;
3010	}
3011	*ptrp = rptr;
3012	*stat = 1;
3013	return 0;
3014out0:
3015	*stat = 0;
3016	return 0;
3017
3018error0:
3019	return error;
3020}
3021
3022#ifdef __KERNEL__
3023struct xfs_btree_split_args {
3024	struct xfs_btree_cur	*cur;
3025	int			level;
3026	union xfs_btree_ptr	*ptrp;
3027	union xfs_btree_key	*key;
3028	struct xfs_btree_cur	**curp;
3029	int			*stat;		/* success/failure */
3030	int			result;
3031	bool			kswapd;	/* allocation in kswapd context */
3032	struct completion	*done;
3033	struct work_struct	work;
3034};
3035
3036/*
3037 * Stack switching interfaces for allocation
3038 */
3039static void
3040xfs_btree_split_worker(
3041	struct work_struct	*work)
3042{
3043	struct xfs_btree_split_args	*args = container_of(work,
3044						struct xfs_btree_split_args, work);
3045	unsigned long		pflags;
3046	unsigned long		new_pflags = 0;
3047
3048	/*
3049	 * we are in a transaction context here, but may also be doing work
3050	 * in kswapd context, and hence we may need to inherit that state
3051	 * temporarily to ensure that we don't block waiting for memory reclaim
3052	 * in any way.
3053	 */
3054	if (args->kswapd)
3055		new_pflags |= PF_MEMALLOC | PF_KSWAPD;
3056
3057	current_set_flags_nested(&pflags, new_pflags);
3058	xfs_trans_set_context(args->cur->bc_tp);
3059
3060	args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
3061					 args->key, args->curp, args->stat);
3062
3063	xfs_trans_clear_context(args->cur->bc_tp);
3064	current_restore_flags_nested(&pflags, new_pflags);
3065
3066	/*
3067	 * Do not access args after complete() has run here. We don't own args
3068	 * and the owner may run and free args before we return here.
3069	 */
3070	complete(args->done);
3071
 
3072}
3073
3074/*
3075 * BMBT split requests often come in with little stack to work on so we push
3076 * them off to a worker thread so there is lots of stack to use. For the other
3077 * btree types, just call directly to avoid the context switch overhead here.
3078 *
3079 * Care must be taken here - the work queue rescuer thread introduces potential
3080 * AGF <> worker queue deadlocks if the BMBT block allocation has to lock new
3081 * AGFs to allocate blocks. A task being run by the rescuer could attempt to
3082 * lock an AGF that is already locked by a task queued to run by the rescuer,
3083 * resulting in an ABBA deadlock as the rescuer cannot run the lock holder to
3084 * release it until the current thread it is running gains the lock.
3085 *
3086 * To avoid this issue, we only ever queue BMBT splits that don't have an AGF
3087 * already locked to allocate from. The only place that doesn't hold an AGF
3088 * locked is unwritten extent conversion at IO completion, but that has already
3089 * been offloaded to a worker thread and hence has no stack consumption issues
3090 * we have to worry about.
3091 */
3092STATIC int					/* error */
3093xfs_btree_split(
3094	struct xfs_btree_cur	*cur,
3095	int			level,
3096	union xfs_btree_ptr	*ptrp,
3097	union xfs_btree_key	*key,
3098	struct xfs_btree_cur	**curp,
3099	int			*stat)		/* success/failure */
3100{
3101	struct xfs_btree_split_args	args;
3102	DECLARE_COMPLETION_ONSTACK(done);
3103
3104	if (!xfs_btree_is_bmap(cur->bc_ops) ||
3105	    cur->bc_tp->t_highest_agno == NULLAGNUMBER)
3106		return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
3107
3108	args.cur = cur;
3109	args.level = level;
3110	args.ptrp = ptrp;
3111	args.key = key;
3112	args.curp = curp;
3113	args.stat = stat;
3114	args.done = &done;
3115	args.kswapd = current_is_kswapd();
3116	INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
3117	queue_work(xfs_alloc_wq, &args.work);
3118	wait_for_completion(&done);
3119	destroy_work_on_stack(&args.work);
3120	return args.result;
3121}
3122#else
3123#define xfs_btree_split	__xfs_btree_split
3124#endif /* __KERNEL__ */
3125
3126/*
3127 * Copy the old inode root contents into a real block and make the
3128 * broot point to it.
3129 */
3130int						/* error */
3131xfs_btree_new_iroot(
3132	struct xfs_btree_cur	*cur,		/* btree cursor */
3133	int			*logflags,	/* logging flags for inode */
3134	int			*stat)		/* return status - 0 fail */
3135{
3136	struct xfs_buf		*cbp;		/* buffer for cblock */
3137	struct xfs_btree_block	*block;		/* btree block */
3138	struct xfs_btree_block	*cblock;	/* child btree block */
3139	union xfs_btree_key	*ckp;		/* child key pointer */
3140	union xfs_btree_ptr	*cpp;		/* child ptr pointer */
3141	union xfs_btree_key	*kp;		/* pointer to btree key */
3142	union xfs_btree_ptr	*pp;		/* pointer to block addr */
3143	union xfs_btree_ptr	nptr;		/* new block addr */
3144	int			level;		/* btree level */
3145	int			error;		/* error return code */
3146	int			i;		/* loop counter */
3147
3148	XFS_BTREE_STATS_INC(cur, newroot);
3149
3150	ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_INODE);
3151
3152	level = cur->bc_nlevels - 1;
3153
3154	block = xfs_btree_get_iroot(cur);
3155	pp = xfs_btree_ptr_addr(cur, 1, block);
3156
3157	/* Allocate the new block. If we can't do it, we're toast. Give up. */
3158	error = xfs_btree_alloc_block(cur, pp, &nptr, stat);
3159	if (error)
3160		goto error0;
3161	if (*stat == 0)
3162		return 0;
3163
3164	XFS_BTREE_STATS_INC(cur, alloc);
3165
3166	/* Copy the root into a real block. */
3167	error = xfs_btree_get_buf_block(cur, &nptr, &cblock, &cbp);
3168	if (error)
3169		goto error0;
3170
3171	/*
3172	 * we can't just memcpy() the root in for CRC enabled btree blocks.
3173	 * In that case have to also ensure the blkno remains correct
3174	 */
3175	memcpy(cblock, block, xfs_btree_block_len(cur));
3176	if (xfs_has_crc(cur->bc_mp)) {
3177		__be64 bno = cpu_to_be64(xfs_buf_daddr(cbp));
3178		if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
3179			cblock->bb_u.l.bb_blkno = bno;
3180		else
3181			cblock->bb_u.s.bb_blkno = bno;
3182	}
3183
3184	be16_add_cpu(&block->bb_level, 1);
3185	xfs_btree_set_numrecs(block, 1);
3186	cur->bc_nlevels++;
3187	ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3188	cur->bc_levels[level + 1].ptr = 1;
3189
3190	kp = xfs_btree_key_addr(cur, 1, block);
3191	ckp = xfs_btree_key_addr(cur, 1, cblock);
3192	xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
3193
3194	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3195	for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
3196		error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3197		if (error)
3198			goto error0;
3199	}
3200
3201	xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
3202
3203	error = xfs_btree_debug_check_ptr(cur, &nptr, 0, level);
3204	if (error)
3205		goto error0;
3206
3207	xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
3208
3209	xfs_iroot_realloc(cur->bc_ino.ip,
3210			  1 - xfs_btree_get_numrecs(cblock),
3211			  cur->bc_ino.whichfork);
3212
3213	xfs_btree_setbuf(cur, level, cbp);
3214
3215	/*
3216	 * Do all this logging at the end so that
3217	 * the root is at the right level.
3218	 */
3219	xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
3220	xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3221	xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
3222
3223	*logflags |=
3224		XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork);
3225	*stat = 1;
3226	return 0;
3227error0:
3228	return error;
3229}
3230
3231static void
3232xfs_btree_set_root(
3233	struct xfs_btree_cur		*cur,
3234	const union xfs_btree_ptr	*ptr,
3235	int				inc)
3236{
3237	if (cur->bc_flags & XFS_BTREE_STAGING) {
3238		/* Update the btree root information for a per-AG fake root. */
3239		cur->bc_ag.afake->af_root = be32_to_cpu(ptr->s);
3240		cur->bc_ag.afake->af_levels += inc;
3241	} else {
3242		cur->bc_ops->set_root(cur, ptr, inc);
3243	}
3244}
3245
3246/*
3247 * Allocate a new root block, fill it in.
3248 */
3249STATIC int				/* error */
3250xfs_btree_new_root(
3251	struct xfs_btree_cur	*cur,	/* btree cursor */
3252	int			*stat)	/* success/failure */
3253{
3254	struct xfs_btree_block	*block;	/* one half of the old root block */
3255	struct xfs_buf		*bp;	/* buffer containing block */
3256	int			error;	/* error return value */
3257	struct xfs_buf		*lbp;	/* left buffer pointer */
3258	struct xfs_btree_block	*left;	/* left btree block */
3259	struct xfs_buf		*nbp;	/* new (root) buffer */
3260	struct xfs_btree_block	*new;	/* new (root) btree block */
3261	int			nptr;	/* new value for key index, 1 or 2 */
3262	struct xfs_buf		*rbp;	/* right buffer pointer */
3263	struct xfs_btree_block	*right;	/* right btree block */
3264	union xfs_btree_ptr	rptr;
3265	union xfs_btree_ptr	lptr;
3266
3267	XFS_BTREE_STATS_INC(cur, newroot);
3268
3269	/* initialise our start point from the cursor */
3270	xfs_btree_init_ptr_from_cur(cur, &rptr);
3271
3272	/* Allocate the new block. If we can't do it, we're toast. Give up. */
3273	error = xfs_btree_alloc_block(cur, &rptr, &lptr, stat);
3274	if (error)
3275		goto error0;
3276	if (*stat == 0)
3277		goto out0;
3278	XFS_BTREE_STATS_INC(cur, alloc);
3279
3280	/* Set up the new block. */
3281	error = xfs_btree_get_buf_block(cur, &lptr, &new, &nbp);
3282	if (error)
3283		goto error0;
3284
3285	/* Set the root in the holding structure  increasing the level by 1. */
3286	xfs_btree_set_root(cur, &lptr, 1);
3287
3288	/*
3289	 * At the previous root level there are now two blocks: the old root,
3290	 * and the new block generated when it was split.  We don't know which
3291	 * one the cursor is pointing at, so we set up variables "left" and
3292	 * "right" for each case.
3293	 */
3294	block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
3295
3296#ifdef DEBUG
3297	error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
3298	if (error)
3299		goto error0;
3300#endif
3301
3302	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3303	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3304		/* Our block is left, pick up the right block. */
3305		lbp = bp;
3306		xfs_btree_buf_to_ptr(cur, lbp, &lptr);
3307		left = block;
3308		error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
3309		if (error)
3310			goto error0;
3311		bp = rbp;
3312		nptr = 1;
3313	} else {
3314		/* Our block is right, pick up the left block. */
3315		rbp = bp;
3316		xfs_btree_buf_to_ptr(cur, rbp, &rptr);
3317		right = block;
3318		xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
3319		error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
3320		if (error)
3321			goto error0;
3322		bp = lbp;
3323		nptr = 2;
3324	}
3325
3326	/* Fill in the new block's btree header and log it. */
3327	xfs_btree_init_block_cur(cur, nbp, cur->bc_nlevels, 2);
3328	xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
3329	ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
3330			!xfs_btree_ptr_is_null(cur, &rptr));
3331
3332	/* Fill in the key data in the new root. */
3333	if (xfs_btree_get_level(left) > 0) {
3334		/*
3335		 * Get the keys for the left block's keys and put them directly
3336		 * in the parent block.  Do the same for the right block.
3337		 */
3338		xfs_btree_get_node_keys(cur, left,
3339				xfs_btree_key_addr(cur, 1, new));
3340		xfs_btree_get_node_keys(cur, right,
3341				xfs_btree_key_addr(cur, 2, new));
3342	} else {
3343		/*
3344		 * Get the keys for the left block's records and put them
3345		 * directly in the parent block.  Do the same for the right
3346		 * block.
3347		 */
3348		xfs_btree_get_leaf_keys(cur, left,
3349			xfs_btree_key_addr(cur, 1, new));
3350		xfs_btree_get_leaf_keys(cur, right,
3351			xfs_btree_key_addr(cur, 2, new));
3352	}
3353	xfs_btree_log_keys(cur, nbp, 1, 2);
3354
3355	/* Fill in the pointer data in the new root. */
3356	xfs_btree_copy_ptrs(cur,
3357		xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
3358	xfs_btree_copy_ptrs(cur,
3359		xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
3360	xfs_btree_log_ptrs(cur, nbp, 1, 2);
3361
3362	/* Fix up the cursor. */
3363	xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
3364	cur->bc_levels[cur->bc_nlevels].ptr = nptr;
3365	cur->bc_nlevels++;
3366	ASSERT(cur->bc_nlevels <= cur->bc_maxlevels);
3367	*stat = 1;
3368	return 0;
3369error0:
3370	return error;
3371out0:
3372	*stat = 0;
3373	return 0;
3374}
3375
3376STATIC int
3377xfs_btree_make_block_unfull(
3378	struct xfs_btree_cur	*cur,	/* btree cursor */
3379	int			level,	/* btree level */
3380	int			numrecs,/* # of recs in block */
3381	int			*oindex,/* old tree index */
3382	int			*index,	/* new tree index */
3383	union xfs_btree_ptr	*nptr,	/* new btree ptr */
3384	struct xfs_btree_cur	**ncur,	/* new btree cursor */
3385	union xfs_btree_key	*key,	/* key of new block */
3386	int			*stat)
3387{
3388	int			error = 0;
3389
3390	if (xfs_btree_at_iroot(cur, level)) {
3391		struct xfs_inode *ip = cur->bc_ino.ip;
 
3392
3393		if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
3394			/* A root block that can be made bigger. */
3395			xfs_iroot_realloc(ip, 1, cur->bc_ino.whichfork);
3396			*stat = 1;
3397		} else {
3398			/* A root block that needs replacing */
3399			int	logflags = 0;
3400
3401			error = xfs_btree_new_iroot(cur, &logflags, stat);
3402			if (error || *stat == 0)
3403				return error;
3404
3405			xfs_trans_log_inode(cur->bc_tp, ip, logflags);
3406		}
3407
3408		return 0;
3409	}
3410
3411	/* First, try shifting an entry to the right neighbor. */
3412	error = xfs_btree_rshift(cur, level, stat);
3413	if (error || *stat)
3414		return error;
3415
3416	/* Next, try shifting an entry to the left neighbor. */
3417	error = xfs_btree_lshift(cur, level, stat);
3418	if (error)
3419		return error;
3420
3421	if (*stat) {
3422		*oindex = *index = cur->bc_levels[level].ptr;
3423		return 0;
3424	}
3425
3426	/*
3427	 * Next, try splitting the current block in half.
3428	 *
3429	 * If this works we have to re-set our variables because we
3430	 * could be in a different block now.
3431	 */
3432	error = xfs_btree_split(cur, level, nptr, key, ncur, stat);
3433	if (error || *stat == 0)
3434		return error;
3435
3436
3437	*index = cur->bc_levels[level].ptr;
3438	return 0;
3439}
3440
3441/*
3442 * Insert one record/level.  Return information to the caller
3443 * allowing the next level up to proceed if necessary.
3444 */
3445STATIC int
3446xfs_btree_insrec(
3447	struct xfs_btree_cur	*cur,	/* btree cursor */
3448	int			level,	/* level to insert record at */
3449	union xfs_btree_ptr	*ptrp,	/* i/o: block number inserted */
3450	union xfs_btree_rec	*rec,	/* record to insert */
3451	union xfs_btree_key	*key,	/* i/o: block key for ptrp */
3452	struct xfs_btree_cur	**curp,	/* output: new cursor replacing cur */
3453	int			*stat)	/* success/failure */
3454{
3455	struct xfs_btree_block	*block;	/* btree block */
3456	struct xfs_buf		*bp;	/* buffer for block */
3457	union xfs_btree_ptr	nptr;	/* new block ptr */
3458	struct xfs_btree_cur	*ncur = NULL;	/* new btree cursor */
3459	union xfs_btree_key	nkey;	/* new block key */
3460	union xfs_btree_key	*lkey;
3461	int			optr;	/* old key/record index */
3462	int			ptr;	/* key/record index */
3463	int			numrecs;/* number of records */
3464	int			error;	/* error return value */
3465	int			i;
3466	xfs_daddr_t		old_bn;
3467
3468	ncur = NULL;
3469	lkey = &nkey;
3470
3471	/*
3472	 * If we have an external root pointer, and we've made it to the
3473	 * root level, allocate a new root block and we're done.
3474	 */
3475	if (cur->bc_ops->type != XFS_BTREE_TYPE_INODE &&
3476	    level >= cur->bc_nlevels) {
3477		error = xfs_btree_new_root(cur, stat);
3478		xfs_btree_set_ptr_null(cur, ptrp);
3479
3480		return error;
3481	}
3482
3483	/* If we're off the left edge, return failure. */
3484	ptr = cur->bc_levels[level].ptr;
3485	if (ptr == 0) {
3486		*stat = 0;
3487		return 0;
3488	}
3489
3490	optr = ptr;
3491
3492	XFS_BTREE_STATS_INC(cur, insrec);
3493
3494	/* Get pointers to the btree buffer and block. */
3495	block = xfs_btree_get_block(cur, level, &bp);
3496	old_bn = bp ? xfs_buf_daddr(bp) : XFS_BUF_DADDR_NULL;
3497	numrecs = xfs_btree_get_numrecs(block);
3498
3499#ifdef DEBUG
3500	error = xfs_btree_check_block(cur, block, level, bp);
3501	if (error)
3502		goto error0;
3503
3504	/* Check that the new entry is being inserted in the right place. */
3505	if (ptr <= numrecs) {
3506		if (level == 0) {
3507			ASSERT(cur->bc_ops->recs_inorder(cur, rec,
3508				xfs_btree_rec_addr(cur, ptr, block)));
3509		} else {
3510			ASSERT(cur->bc_ops->keys_inorder(cur, key,
3511				xfs_btree_key_addr(cur, ptr, block)));
3512		}
3513	}
3514#endif
3515
3516	/*
3517	 * If the block is full, we can't insert the new entry until we
3518	 * make the block un-full.
3519	 */
3520	xfs_btree_set_ptr_null(cur, &nptr);
3521	if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
3522		error = xfs_btree_make_block_unfull(cur, level, numrecs,
3523					&optr, &ptr, &nptr, &ncur, lkey, stat);
3524		if (error || *stat == 0)
3525			goto error0;
3526	}
3527
3528	/*
3529	 * The current block may have changed if the block was
3530	 * previously full and we have just made space in it.
3531	 */
3532	block = xfs_btree_get_block(cur, level, &bp);
3533	numrecs = xfs_btree_get_numrecs(block);
3534
3535#ifdef DEBUG
3536	error = xfs_btree_check_block(cur, block, level, bp);
3537	if (error)
3538		goto error0;
3539#endif
3540
3541	/*
3542	 * At this point we know there's room for our new entry in the block
3543	 * we're pointing at.
3544	 */
3545	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
3546
3547	if (level > 0) {
3548		/* It's a nonleaf. make a hole in the keys and ptrs */
3549		union xfs_btree_key	*kp;
3550		union xfs_btree_ptr	*pp;
3551
3552		kp = xfs_btree_key_addr(cur, ptr, block);
3553		pp = xfs_btree_ptr_addr(cur, ptr, block);
3554
3555		for (i = numrecs - ptr; i >= 0; i--) {
3556			error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3557			if (error)
3558				goto error0;
3559		}
3560
3561		xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
3562		xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
3563
3564		error = xfs_btree_debug_check_ptr(cur, ptrp, 0, level);
3565		if (error)
3566			goto error0;
3567
3568		/* Now put the new data in, bump numrecs and log it. */
3569		xfs_btree_copy_keys(cur, kp, key, 1);
3570		xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
3571		numrecs++;
3572		xfs_btree_set_numrecs(block, numrecs);
3573		xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
3574		xfs_btree_log_keys(cur, bp, ptr, numrecs);
3575#ifdef DEBUG
3576		if (ptr < numrecs) {
3577			ASSERT(cur->bc_ops->keys_inorder(cur, kp,
3578				xfs_btree_key_addr(cur, ptr + 1, block)));
3579		}
3580#endif
3581	} else {
3582		/* It's a leaf. make a hole in the records */
3583		union xfs_btree_rec             *rp;
3584
3585		rp = xfs_btree_rec_addr(cur, ptr, block);
3586
3587		xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
3588
3589		/* Now put the new data in, bump numrecs and log it. */
3590		xfs_btree_copy_recs(cur, rp, rec, 1);
3591		xfs_btree_set_numrecs(block, ++numrecs);
3592		xfs_btree_log_recs(cur, bp, ptr, numrecs);
3593#ifdef DEBUG
3594		if (ptr < numrecs) {
3595			ASSERT(cur->bc_ops->recs_inorder(cur, rp,
3596				xfs_btree_rec_addr(cur, ptr + 1, block)));
3597		}
3598#endif
3599	}
3600
3601	/* Log the new number of records in the btree header. */
3602	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3603
3604	/*
3605	 * If we just inserted into a new tree block, we have to
3606	 * recalculate nkey here because nkey is out of date.
3607	 *
3608	 * Otherwise we're just updating an existing block (having shoved
3609	 * some records into the new tree block), so use the regular key
3610	 * update mechanism.
3611	 */
3612	if (bp && xfs_buf_daddr(bp) != old_bn) {
3613		xfs_btree_get_keys(cur, block, lkey);
3614	} else if (xfs_btree_needs_key_update(cur, optr)) {
3615		error = xfs_btree_update_keys(cur, level);
3616		if (error)
3617			goto error0;
3618	}
3619
3620	/*
3621	 * If we are tracking the last record in the tree and
3622	 * we are at the far right edge of the tree, update it.
3623	 */
3624	if (xfs_btree_is_lastrec(cur, block, level)) {
3625		cur->bc_ops->update_lastrec(cur, block, rec,
3626					    ptr, LASTREC_INSREC);
3627	}
3628
3629	/*
3630	 * Return the new block number, if any.
3631	 * If there is one, give back a record value and a cursor too.
3632	 */
3633	*ptrp = nptr;
3634	if (!xfs_btree_ptr_is_null(cur, &nptr)) {
3635		xfs_btree_copy_keys(cur, key, lkey, 1);
3636		*curp = ncur;
3637	}
3638
3639	*stat = 1;
3640	return 0;
3641
3642error0:
3643	if (ncur)
3644		xfs_btree_del_cursor(ncur, error);
3645	return error;
3646}
3647
3648/*
3649 * Insert the record at the point referenced by cur.
3650 *
3651 * A multi-level split of the tree on insert will invalidate the original
3652 * cursor.  All callers of this function should assume that the cursor is
3653 * no longer valid and revalidate it.
3654 */
3655int
3656xfs_btree_insert(
3657	struct xfs_btree_cur	*cur,
3658	int			*stat)
3659{
3660	int			error;	/* error return value */
3661	int			i;	/* result value, 0 for failure */
3662	int			level;	/* current level number in btree */
3663	union xfs_btree_ptr	nptr;	/* new block number (split result) */
3664	struct xfs_btree_cur	*ncur;	/* new cursor (split result) */
3665	struct xfs_btree_cur	*pcur;	/* previous level's cursor */
3666	union xfs_btree_key	bkey;	/* key of block to insert */
3667	union xfs_btree_key	*key;
3668	union xfs_btree_rec	rec;	/* record to insert */
3669
3670	level = 0;
3671	ncur = NULL;
3672	pcur = cur;
3673	key = &bkey;
3674
3675	xfs_btree_set_ptr_null(cur, &nptr);
3676
3677	/* Make a key out of the record data to be inserted, and save it. */
3678	cur->bc_ops->init_rec_from_cur(cur, &rec);
3679	cur->bc_ops->init_key_from_rec(key, &rec);
3680
3681	/*
3682	 * Loop going up the tree, starting at the leaf level.
3683	 * Stop when we don't get a split block, that must mean that
3684	 * the insert is finished with this level.
3685	 */
3686	do {
3687		/*
3688		 * Insert nrec/nptr into this level of the tree.
3689		 * Note if we fail, nptr will be null.
3690		 */
3691		error = xfs_btree_insrec(pcur, level, &nptr, &rec, key,
3692				&ncur, &i);
3693		if (error) {
3694			if (pcur != cur)
3695				xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
3696			goto error0;
3697		}
3698
3699		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3700			xfs_btree_mark_sick(cur);
3701			error = -EFSCORRUPTED;
3702			goto error0;
3703		}
3704		level++;
3705
3706		/*
3707		 * See if the cursor we just used is trash.
3708		 * Can't trash the caller's cursor, but otherwise we should
3709		 * if ncur is a new cursor or we're about to be done.
3710		 */
3711		if (pcur != cur &&
3712		    (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
3713			/* Save the state from the cursor before we trash it */
3714			if (cur->bc_ops->update_cursor &&
3715			    !(cur->bc_flags & XFS_BTREE_STAGING))
3716				cur->bc_ops->update_cursor(pcur, cur);
3717			cur->bc_nlevels = pcur->bc_nlevels;
3718			xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
3719		}
3720		/* If we got a new cursor, switch to it. */
3721		if (ncur) {
3722			pcur = ncur;
3723			ncur = NULL;
3724		}
3725	} while (!xfs_btree_ptr_is_null(cur, &nptr));
3726
3727	*stat = i;
3728	return 0;
3729error0:
3730	return error;
3731}
3732
3733/*
3734 * Try to merge a non-leaf block back into the inode root.
3735 *
3736 * Note: the killroot names comes from the fact that we're effectively
3737 * killing the old root block.  But because we can't just delete the
3738 * inode we have to copy the single block it was pointing to into the
3739 * inode.
3740 */
3741STATIC int
3742xfs_btree_kill_iroot(
3743	struct xfs_btree_cur	*cur)
3744{
3745	int			whichfork = cur->bc_ino.whichfork;
3746	struct xfs_inode	*ip = cur->bc_ino.ip;
3747	struct xfs_ifork	*ifp = xfs_ifork_ptr(ip, whichfork);
3748	struct xfs_btree_block	*block;
3749	struct xfs_btree_block	*cblock;
3750	union xfs_btree_key	*kp;
3751	union xfs_btree_key	*ckp;
3752	union xfs_btree_ptr	*pp;
3753	union xfs_btree_ptr	*cpp;
3754	struct xfs_buf		*cbp;
3755	int			level;
3756	int			index;
3757	int			numrecs;
3758	int			error;
3759#ifdef DEBUG
3760	union xfs_btree_ptr	ptr;
3761#endif
3762	int			i;
3763
3764	ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_INODE);
3765	ASSERT(cur->bc_nlevels > 1);
3766
3767	/*
3768	 * Don't deal with the root block needs to be a leaf case.
3769	 * We're just going to turn the thing back into extents anyway.
3770	 */
3771	level = cur->bc_nlevels - 1;
3772	if (level == 1)
3773		goto out0;
3774
3775	/*
3776	 * Give up if the root has multiple children.
3777	 */
3778	block = xfs_btree_get_iroot(cur);
3779	if (xfs_btree_get_numrecs(block) != 1)
3780		goto out0;
3781
3782	cblock = xfs_btree_get_block(cur, level - 1, &cbp);
3783	numrecs = xfs_btree_get_numrecs(cblock);
3784
3785	/*
3786	 * Only do this if the next level will fit.
3787	 * Then the data must be copied up to the inode,
3788	 * instead of freeing the root you free the next level.
3789	 */
3790	if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
3791		goto out0;
3792
3793	XFS_BTREE_STATS_INC(cur, killroot);
3794
3795#ifdef DEBUG
3796	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
3797	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3798	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
3799	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3800#endif
3801
3802	index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
3803	if (index) {
3804		xfs_iroot_realloc(cur->bc_ino.ip, index,
3805				  cur->bc_ino.whichfork);
3806		block = ifp->if_broot;
3807	}
3808
3809	be16_add_cpu(&block->bb_numrecs, index);
3810	ASSERT(block->bb_numrecs == cblock->bb_numrecs);
3811
3812	kp = xfs_btree_key_addr(cur, 1, block);
3813	ckp = xfs_btree_key_addr(cur, 1, cblock);
3814	xfs_btree_copy_keys(cur, kp, ckp, numrecs);
3815
3816	pp = xfs_btree_ptr_addr(cur, 1, block);
3817	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3818
3819	for (i = 0; i < numrecs; i++) {
3820		error = xfs_btree_debug_check_ptr(cur, cpp, i, level - 1);
3821		if (error)
3822			return error;
3823	}
3824
3825	xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
3826
3827	error = xfs_btree_free_block(cur, cbp);
3828	if (error)
3829		return error;
3830
3831	cur->bc_levels[level - 1].bp = NULL;
3832	be16_add_cpu(&block->bb_level, -1);
3833	xfs_trans_log_inode(cur->bc_tp, ip,
3834		XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork));
3835	cur->bc_nlevels--;
3836out0:
3837	return 0;
3838}
3839
3840/*
3841 * Kill the current root node, and replace it with it's only child node.
3842 */
3843STATIC int
3844xfs_btree_kill_root(
3845	struct xfs_btree_cur	*cur,
3846	struct xfs_buf		*bp,
3847	int			level,
3848	union xfs_btree_ptr	*newroot)
3849{
3850	int			error;
3851
3852	XFS_BTREE_STATS_INC(cur, killroot);
3853
3854	/*
3855	 * Update the root pointer, decreasing the level by 1 and then
3856	 * free the old root.
3857	 */
3858	xfs_btree_set_root(cur, newroot, -1);
3859
3860	error = xfs_btree_free_block(cur, bp);
3861	if (error)
3862		return error;
3863
3864	cur->bc_levels[level].bp = NULL;
3865	cur->bc_levels[level].ra = 0;
3866	cur->bc_nlevels--;
3867
3868	return 0;
3869}
3870
3871STATIC int
3872xfs_btree_dec_cursor(
3873	struct xfs_btree_cur	*cur,
3874	int			level,
3875	int			*stat)
3876{
3877	int			error;
3878	int			i;
3879
3880	if (level > 0) {
3881		error = xfs_btree_decrement(cur, level, &i);
3882		if (error)
3883			return error;
3884	}
3885
3886	*stat = 1;
3887	return 0;
3888}
3889
3890/*
3891 * Single level of the btree record deletion routine.
3892 * Delete record pointed to by cur/level.
3893 * Remove the record from its block then rebalance the tree.
3894 * Return 0 for error, 1 for done, 2 to go on to the next level.
3895 */
3896STATIC int					/* error */
3897xfs_btree_delrec(
3898	struct xfs_btree_cur	*cur,		/* btree cursor */
3899	int			level,		/* level removing record from */
3900	int			*stat)		/* fail/done/go-on */
3901{
3902	struct xfs_btree_block	*block;		/* btree block */
3903	union xfs_btree_ptr	cptr;		/* current block ptr */
3904	struct xfs_buf		*bp;		/* buffer for block */
3905	int			error;		/* error return value */
3906	int			i;		/* loop counter */
3907	union xfs_btree_ptr	lptr;		/* left sibling block ptr */
3908	struct xfs_buf		*lbp;		/* left buffer pointer */
3909	struct xfs_btree_block	*left;		/* left btree block */
3910	int			lrecs = 0;	/* left record count */
3911	int			ptr;		/* key/record index */
3912	union xfs_btree_ptr	rptr;		/* right sibling block ptr */
3913	struct xfs_buf		*rbp;		/* right buffer pointer */
3914	struct xfs_btree_block	*right;		/* right btree block */
3915	struct xfs_btree_block	*rrblock;	/* right-right btree block */
3916	struct xfs_buf		*rrbp;		/* right-right buffer pointer */
3917	int			rrecs = 0;	/* right record count */
3918	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
3919	int			numrecs;	/* temporary numrec count */
3920
3921	tcur = NULL;
3922
3923	/* Get the index of the entry being deleted, check for nothing there. */
3924	ptr = cur->bc_levels[level].ptr;
3925	if (ptr == 0) {
3926		*stat = 0;
3927		return 0;
3928	}
3929
3930	/* Get the buffer & block containing the record or key/ptr. */
3931	block = xfs_btree_get_block(cur, level, &bp);
3932	numrecs = xfs_btree_get_numrecs(block);
3933
3934#ifdef DEBUG
3935	error = xfs_btree_check_block(cur, block, level, bp);
3936	if (error)
3937		goto error0;
3938#endif
3939
3940	/* Fail if we're off the end of the block. */
3941	if (ptr > numrecs) {
3942		*stat = 0;
3943		return 0;
3944	}
3945
3946	XFS_BTREE_STATS_INC(cur, delrec);
3947	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3948
3949	/* Excise the entries being deleted. */
3950	if (level > 0) {
3951		/* It's a nonleaf. operate on keys and ptrs */
3952		union xfs_btree_key	*lkp;
3953		union xfs_btree_ptr	*lpp;
3954
3955		lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3956		lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3957
3958		for (i = 0; i < numrecs - ptr; i++) {
3959			error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
3960			if (error)
3961				goto error0;
3962		}
3963
3964		if (ptr < numrecs) {
3965			xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3966			xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3967			xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3968			xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3969		}
3970	} else {
3971		/* It's a leaf. operate on records */
3972		if (ptr < numrecs) {
3973			xfs_btree_shift_recs(cur,
3974				xfs_btree_rec_addr(cur, ptr + 1, block),
3975				-1, numrecs - ptr);
3976			xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3977		}
3978	}
3979
3980	/*
3981	 * Decrement and log the number of entries in the block.
3982	 */
3983	xfs_btree_set_numrecs(block, --numrecs);
3984	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3985
3986	/*
3987	 * If we are tracking the last record in the tree and
3988	 * we are at the far right edge of the tree, update it.
3989	 */
3990	if (xfs_btree_is_lastrec(cur, block, level)) {
3991		cur->bc_ops->update_lastrec(cur, block, NULL,
3992					    ptr, LASTREC_DELREC);
3993	}
3994
3995	/*
3996	 * We're at the root level.  First, shrink the root block in-memory.
3997	 * Try to get rid of the next level down.  If we can't then there's
3998	 * nothing left to do.
3999	 */
4000	if (xfs_btree_at_iroot(cur, level)) {
4001		xfs_iroot_realloc(cur->bc_ino.ip, -1, cur->bc_ino.whichfork);
 
 
4002
4003		error = xfs_btree_kill_iroot(cur);
4004		if (error)
4005			goto error0;
4006
4007		error = xfs_btree_dec_cursor(cur, level, stat);
4008		if (error)
4009			goto error0;
4010		*stat = 1;
4011		return 0;
4012	}
4013
4014	/*
4015	 * If this is the root level, and there's only one entry left, and it's
4016	 * NOT the leaf level, then we can get rid of this level.
4017	 */
4018	if (level == cur->bc_nlevels - 1) {
4019		if (numrecs == 1 && level > 0) {
4020			union xfs_btree_ptr	*pp;
4021			/*
4022			 * pp is still set to the first pointer in the block.
4023			 * Make it the new root of the btree.
4024			 */
4025			pp = xfs_btree_ptr_addr(cur, 1, block);
4026			error = xfs_btree_kill_root(cur, bp, level, pp);
4027			if (error)
4028				goto error0;
4029		} else if (level > 0) {
4030			error = xfs_btree_dec_cursor(cur, level, stat);
4031			if (error)
4032				goto error0;
4033		}
4034		*stat = 1;
4035		return 0;
4036	}
4037
4038	/*
4039	 * If we deleted the leftmost entry in the block, update the
4040	 * key values above us in the tree.
4041	 */
4042	if (xfs_btree_needs_key_update(cur, ptr)) {
4043		error = xfs_btree_update_keys(cur, level);
4044		if (error)
4045			goto error0;
4046	}
4047
4048	/*
4049	 * If the number of records remaining in the block is at least
4050	 * the minimum, we're done.
4051	 */
4052	if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
4053		error = xfs_btree_dec_cursor(cur, level, stat);
4054		if (error)
4055			goto error0;
4056		return 0;
4057	}
4058
4059	/*
4060	 * Otherwise, we have to move some records around to keep the
4061	 * tree balanced.  Look at the left and right sibling blocks to
4062	 * see if we can re-balance by moving only one record.
4063	 */
4064	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
4065	xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
4066
4067	if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE) {
4068		/*
4069		 * One child of root, need to get a chance to copy its contents
4070		 * into the root and delete it. Can't go up to next level,
4071		 * there's nothing to delete there.
4072		 */
4073		if (xfs_btree_ptr_is_null(cur, &rptr) &&
4074		    xfs_btree_ptr_is_null(cur, &lptr) &&
4075		    level == cur->bc_nlevels - 2) {
4076			error = xfs_btree_kill_iroot(cur);
4077			if (!error)
4078				error = xfs_btree_dec_cursor(cur, level, stat);
4079			if (error)
4080				goto error0;
4081			return 0;
4082		}
4083	}
4084
4085	ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
4086	       !xfs_btree_ptr_is_null(cur, &lptr));
4087
4088	/*
4089	 * Duplicate the cursor so our btree manipulations here won't
4090	 * disrupt the next level up.
4091	 */
4092	error = xfs_btree_dup_cursor(cur, &tcur);
4093	if (error)
4094		goto error0;
4095
4096	/*
4097	 * If there's a right sibling, see if it's ok to shift an entry
4098	 * out of it.
4099	 */
4100	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
4101		/*
4102		 * Move the temp cursor to the last entry in the next block.
4103		 * Actually any entry but the first would suffice.
4104		 */
4105		i = xfs_btree_lastrec(tcur, level);
4106		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4107			xfs_btree_mark_sick(cur);
4108			error = -EFSCORRUPTED;
4109			goto error0;
4110		}
4111
4112		error = xfs_btree_increment(tcur, level, &i);
4113		if (error)
4114			goto error0;
4115		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4116			xfs_btree_mark_sick(cur);
4117			error = -EFSCORRUPTED;
4118			goto error0;
4119		}
4120
4121		i = xfs_btree_lastrec(tcur, level);
4122		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4123			xfs_btree_mark_sick(cur);
4124			error = -EFSCORRUPTED;
4125			goto error0;
4126		}
4127
4128		/* Grab a pointer to the block. */
4129		right = xfs_btree_get_block(tcur, level, &rbp);
4130#ifdef DEBUG
4131		error = xfs_btree_check_block(tcur, right, level, rbp);
4132		if (error)
4133			goto error0;
4134#endif
4135		/* Grab the current block number, for future use. */
4136		xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
4137
4138		/*
4139		 * If right block is full enough so that removing one entry
4140		 * won't make it too empty, and left-shifting an entry out
4141		 * of right to us works, we're done.
4142		 */
4143		if (xfs_btree_get_numrecs(right) - 1 >=
4144		    cur->bc_ops->get_minrecs(tcur, level)) {
4145			error = xfs_btree_lshift(tcur, level, &i);
4146			if (error)
4147				goto error0;
4148			if (i) {
4149				ASSERT(xfs_btree_get_numrecs(block) >=
4150				       cur->bc_ops->get_minrecs(tcur, level));
4151
4152				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
4153				tcur = NULL;
4154
4155				error = xfs_btree_dec_cursor(cur, level, stat);
4156				if (error)
4157					goto error0;
4158				return 0;
4159			}
4160		}
4161
4162		/*
4163		 * Otherwise, grab the number of records in right for
4164		 * future reference, and fix up the temp cursor to point
4165		 * to our block again (last record).
4166		 */
4167		rrecs = xfs_btree_get_numrecs(right);
4168		if (!xfs_btree_ptr_is_null(cur, &lptr)) {
4169			i = xfs_btree_firstrec(tcur, level);
4170			if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4171				xfs_btree_mark_sick(cur);
4172				error = -EFSCORRUPTED;
4173				goto error0;
4174			}
4175
4176			error = xfs_btree_decrement(tcur, level, &i);
4177			if (error)
4178				goto error0;
4179			if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4180				xfs_btree_mark_sick(cur);
4181				error = -EFSCORRUPTED;
4182				goto error0;
4183			}
4184		}
4185	}
4186
4187	/*
4188	 * If there's a left sibling, see if it's ok to shift an entry
4189	 * out of it.
4190	 */
4191	if (!xfs_btree_ptr_is_null(cur, &lptr)) {
4192		/*
4193		 * Move the temp cursor to the first entry in the
4194		 * previous block.
4195		 */
4196		i = xfs_btree_firstrec(tcur, level);
4197		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4198			xfs_btree_mark_sick(cur);
4199			error = -EFSCORRUPTED;
4200			goto error0;
4201		}
4202
4203		error = xfs_btree_decrement(tcur, level, &i);
4204		if (error)
4205			goto error0;
4206		i = xfs_btree_firstrec(tcur, level);
4207		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
4208			xfs_btree_mark_sick(cur);
4209			error = -EFSCORRUPTED;
4210			goto error0;
4211		}
4212
4213		/* Grab a pointer to the block. */
4214		left = xfs_btree_get_block(tcur, level, &lbp);
4215#ifdef DEBUG
4216		error = xfs_btree_check_block(cur, left, level, lbp);
4217		if (error)
4218			goto error0;
4219#endif
4220		/* Grab the current block number, for future use. */
4221		xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
4222
4223		/*
4224		 * If left block is full enough so that removing one entry
4225		 * won't make it too empty, and right-shifting an entry out
4226		 * of left to us works, we're done.
4227		 */
4228		if (xfs_btree_get_numrecs(left) - 1 >=
4229		    cur->bc_ops->get_minrecs(tcur, level)) {
4230			error = xfs_btree_rshift(tcur, level, &i);
4231			if (error)
4232				goto error0;
4233			if (i) {
4234				ASSERT(xfs_btree_get_numrecs(block) >=
4235				       cur->bc_ops->get_minrecs(tcur, level));
4236				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
4237				tcur = NULL;
4238				if (level == 0)
4239					cur->bc_levels[0].ptr++;
4240
4241				*stat = 1;
4242				return 0;
4243			}
4244		}
4245
4246		/*
4247		 * Otherwise, grab the number of records in right for
4248		 * future reference.
4249		 */
4250		lrecs = xfs_btree_get_numrecs(left);
4251	}
4252
4253	/* Delete the temp cursor, we're done with it. */
4254	xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
4255	tcur = NULL;
4256
4257	/* If here, we need to do a join to keep the tree balanced. */
4258	ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
4259
4260	if (!xfs_btree_ptr_is_null(cur, &lptr) &&
4261	    lrecs + xfs_btree_get_numrecs(block) <=
4262			cur->bc_ops->get_maxrecs(cur, level)) {
4263		/*
4264		 * Set "right" to be the starting block,
4265		 * "left" to be the left neighbor.
4266		 */
4267		rptr = cptr;
4268		right = block;
4269		rbp = bp;
4270		error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
4271		if (error)
4272			goto error0;
4273
4274	/*
4275	 * If that won't work, see if we can join with the right neighbor block.
4276	 */
4277	} else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
4278		   rrecs + xfs_btree_get_numrecs(block) <=
4279			cur->bc_ops->get_maxrecs(cur, level)) {
4280		/*
4281		 * Set "left" to be the starting block,
4282		 * "right" to be the right neighbor.
4283		 */
4284		lptr = cptr;
4285		left = block;
4286		lbp = bp;
4287		error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
4288		if (error)
4289			goto error0;
4290
4291	/*
4292	 * Otherwise, we can't fix the imbalance.
4293	 * Just return.  This is probably a logic error, but it's not fatal.
4294	 */
4295	} else {
4296		error = xfs_btree_dec_cursor(cur, level, stat);
4297		if (error)
4298			goto error0;
4299		return 0;
4300	}
4301
4302	rrecs = xfs_btree_get_numrecs(right);
4303	lrecs = xfs_btree_get_numrecs(left);
4304
4305	/*
4306	 * We're now going to join "left" and "right" by moving all the stuff
4307	 * in "right" to "left" and deleting "right".
4308	 */
4309	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
4310	if (level > 0) {
4311		/* It's a non-leaf.  Move keys and pointers. */
4312		union xfs_btree_key	*lkp;	/* left btree key */
4313		union xfs_btree_ptr	*lpp;	/* left address pointer */
4314		union xfs_btree_key	*rkp;	/* right btree key */
4315		union xfs_btree_ptr	*rpp;	/* right address pointer */
4316
4317		lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
4318		lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
4319		rkp = xfs_btree_key_addr(cur, 1, right);
4320		rpp = xfs_btree_ptr_addr(cur, 1, right);
4321
4322		for (i = 1; i < rrecs; i++) {
4323			error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
4324			if (error)
4325				goto error0;
4326		}
4327
4328		xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
4329		xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
4330
4331		xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
4332		xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
4333	} else {
4334		/* It's a leaf.  Move records.  */
4335		union xfs_btree_rec	*lrp;	/* left record pointer */
4336		union xfs_btree_rec	*rrp;	/* right record pointer */
4337
4338		lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
4339		rrp = xfs_btree_rec_addr(cur, 1, right);
4340
4341		xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
4342		xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
4343	}
4344
4345	XFS_BTREE_STATS_INC(cur, join);
4346
4347	/*
4348	 * Fix up the number of records and right block pointer in the
4349	 * surviving block, and log it.
4350	 */
4351	xfs_btree_set_numrecs(left, lrecs + rrecs);
4352	xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB);
4353	xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4354	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
4355
4356	/* If there is a right sibling, point it to the remaining block. */
4357	xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4358	if (!xfs_btree_ptr_is_null(cur, &cptr)) {
4359		error = xfs_btree_read_buf_block(cur, &cptr, 0, &rrblock, &rrbp);
4360		if (error)
4361			goto error0;
4362		xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
4363		xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
4364	}
4365
4366	/* Free the deleted block. */
4367	error = xfs_btree_free_block(cur, rbp);
4368	if (error)
4369		goto error0;
4370
4371	/*
4372	 * If we joined with the left neighbor, set the buffer in the
4373	 * cursor to the left block, and fix up the index.
4374	 */
4375	if (bp != lbp) {
4376		cur->bc_levels[level].bp = lbp;
4377		cur->bc_levels[level].ptr += lrecs;
4378		cur->bc_levels[level].ra = 0;
4379	}
4380	/*
4381	 * If we joined with the right neighbor and there's a level above
4382	 * us, increment the cursor at that level.
4383	 */
4384	else if (cur->bc_ops->type == XFS_BTREE_TYPE_INODE ||
4385		 level + 1 < cur->bc_nlevels) {
4386		error = xfs_btree_increment(cur, level + 1, &i);
4387		if (error)
4388			goto error0;
4389	}
4390
4391	/*
4392	 * Readjust the ptr at this level if it's not a leaf, since it's
4393	 * still pointing at the deletion point, which makes the cursor
4394	 * inconsistent.  If this makes the ptr 0, the caller fixes it up.
4395	 * We can't use decrement because it would change the next level up.
4396	 */
4397	if (level > 0)
4398		cur->bc_levels[level].ptr--;
4399
4400	/*
4401	 * We combined blocks, so we have to update the parent keys if the
4402	 * btree supports overlapped intervals.  However,
4403	 * bc_levels[level + 1].ptr points to the old block so that the caller
4404	 * knows which record to delete.  Therefore, the caller must be savvy
4405	 * enough to call updkeys for us if we return stat == 2.  The other
4406	 * exit points from this function don't require deletions further up
4407	 * the tree, so they can call updkeys directly.
4408	 */
4409
4410	/* Return value means the next level up has something to do. */
4411	*stat = 2;
4412	return 0;
4413
4414error0:
4415	if (tcur)
4416		xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
4417	return error;
4418}
4419
4420/*
4421 * Delete the record pointed to by cur.
4422 * The cursor refers to the place where the record was (could be inserted)
4423 * when the operation returns.
4424 */
4425int					/* error */
4426xfs_btree_delete(
4427	struct xfs_btree_cur	*cur,
4428	int			*stat)	/* success/failure */
4429{
4430	int			error;	/* error return value */
4431	int			level;
4432	int			i;
4433	bool			joined = false;
4434
4435	/*
4436	 * Go up the tree, starting at leaf level.
4437	 *
4438	 * If 2 is returned then a join was done; go to the next level.
4439	 * Otherwise we are done.
4440	 */
4441	for (level = 0, i = 2; i == 2; level++) {
4442		error = xfs_btree_delrec(cur, level, &i);
4443		if (error)
4444			goto error0;
4445		if (i == 2)
4446			joined = true;
4447	}
4448
4449	/*
4450	 * If we combined blocks as part of deleting the record, delrec won't
4451	 * have updated the parent high keys so we have to do that here.
4452	 */
4453	if (joined && (cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING)) {
4454		error = xfs_btree_updkeys_force(cur, 0);
4455		if (error)
4456			goto error0;
4457	}
4458
4459	if (i == 0) {
4460		for (level = 1; level < cur->bc_nlevels; level++) {
4461			if (cur->bc_levels[level].ptr == 0) {
4462				error = xfs_btree_decrement(cur, level, &i);
4463				if (error)
4464					goto error0;
4465				break;
4466			}
4467		}
4468	}
4469
4470	*stat = i;
4471	return 0;
4472error0:
4473	return error;
4474}
4475
4476/*
4477 * Get the data from the pointed-to record.
4478 */
4479int					/* error */
4480xfs_btree_get_rec(
4481	struct xfs_btree_cur	*cur,	/* btree cursor */
4482	union xfs_btree_rec	**recp,	/* output: btree record */
4483	int			*stat)	/* output: success/failure */
4484{
4485	struct xfs_btree_block	*block;	/* btree block */
4486	struct xfs_buf		*bp;	/* buffer pointer */
4487	int			ptr;	/* record number */
4488#ifdef DEBUG
4489	int			error;	/* error return value */
4490#endif
4491
4492	ptr = cur->bc_levels[0].ptr;
4493	block = xfs_btree_get_block(cur, 0, &bp);
4494
4495#ifdef DEBUG
4496	error = xfs_btree_check_block(cur, block, 0, bp);
4497	if (error)
4498		return error;
4499#endif
4500
4501	/*
4502	 * Off the right end or left end, return failure.
4503	 */
4504	if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
4505		*stat = 0;
4506		return 0;
4507	}
4508
4509	/*
4510	 * Point to the record and extract its data.
4511	 */
4512	*recp = xfs_btree_rec_addr(cur, ptr, block);
4513	*stat = 1;
4514	return 0;
4515}
4516
4517/* Visit a block in a btree. */
4518STATIC int
4519xfs_btree_visit_block(
4520	struct xfs_btree_cur		*cur,
4521	int				level,
4522	xfs_btree_visit_blocks_fn	fn,
4523	void				*data)
4524{
4525	struct xfs_btree_block		*block;
4526	struct xfs_buf			*bp;
4527	union xfs_btree_ptr		rptr, bufptr;
4528	int				error;
4529
4530	/* do right sibling readahead */
4531	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
4532	block = xfs_btree_get_block(cur, level, &bp);
4533
4534	/* process the block */
4535	error = fn(cur, level, data);
4536	if (error)
4537		return error;
4538
4539	/* now read rh sibling block for next iteration */
4540	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
4541	if (xfs_btree_ptr_is_null(cur, &rptr))
4542		return -ENOENT;
4543
4544	/*
4545	 * We only visit blocks once in this walk, so we have to avoid the
4546	 * internal xfs_btree_lookup_get_block() optimisation where it will
4547	 * return the same block without checking if the right sibling points
4548	 * back to us and creates a cyclic reference in the btree.
4549	 */
4550	xfs_btree_buf_to_ptr(cur, bp, &bufptr);
4551	if (xfs_btree_ptrs_equal(cur, &rptr, &bufptr)) {
4552		xfs_btree_mark_sick(cur);
4553		return -EFSCORRUPTED;
4554	}
4555
4556	return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
4557}
4558
4559
4560/* Visit every block in a btree. */
4561int
4562xfs_btree_visit_blocks(
4563	struct xfs_btree_cur		*cur,
4564	xfs_btree_visit_blocks_fn	fn,
4565	unsigned int			flags,
4566	void				*data)
4567{
4568	union xfs_btree_ptr		lptr;
4569	int				level;
4570	struct xfs_btree_block		*block = NULL;
4571	int				error = 0;
4572
4573	xfs_btree_init_ptr_from_cur(cur, &lptr);
4574
4575	/* for each level */
4576	for (level = cur->bc_nlevels - 1; level >= 0; level--) {
4577		/* grab the left hand block */
4578		error = xfs_btree_lookup_get_block(cur, level, &lptr, &block);
4579		if (error)
4580			return error;
4581
4582		/* readahead the left most block for the next level down */
4583		if (level > 0) {
4584			union xfs_btree_ptr     *ptr;
4585
4586			ptr = xfs_btree_ptr_addr(cur, 1, block);
4587			xfs_btree_readahead_ptr(cur, ptr, 1);
4588
4589			/* save for the next iteration of the loop */
4590			xfs_btree_copy_ptrs(cur, &lptr, ptr, 1);
4591
4592			if (!(flags & XFS_BTREE_VISIT_LEAVES))
4593				continue;
4594		} else if (!(flags & XFS_BTREE_VISIT_RECORDS)) {
4595			continue;
4596		}
4597
4598		/* for each buffer in the level */
4599		do {
4600			error = xfs_btree_visit_block(cur, level, fn, data);
4601		} while (!error);
4602
4603		if (error != -ENOENT)
4604			return error;
4605	}
4606
4607	return 0;
4608}
4609
4610/*
4611 * Change the owner of a btree.
4612 *
4613 * The mechanism we use here is ordered buffer logging. Because we don't know
4614 * how many buffers were are going to need to modify, we don't really want to
4615 * have to make transaction reservations for the worst case of every buffer in a
4616 * full size btree as that may be more space that we can fit in the log....
4617 *
4618 * We do the btree walk in the most optimal manner possible - we have sibling
4619 * pointers so we can just walk all the blocks on each level from left to right
4620 * in a single pass, and then move to the next level and do the same. We can
4621 * also do readahead on the sibling pointers to get IO moving more quickly,
4622 * though for slow disks this is unlikely to make much difference to performance
4623 * as the amount of CPU work we have to do before moving to the next block is
4624 * relatively small.
4625 *
4626 * For each btree block that we load, modify the owner appropriately, set the
4627 * buffer as an ordered buffer and log it appropriately. We need to ensure that
4628 * we mark the region we change dirty so that if the buffer is relogged in
4629 * a subsequent transaction the changes we make here as an ordered buffer are
4630 * correctly relogged in that transaction.  If we are in recovery context, then
4631 * just queue the modified buffer as delayed write buffer so the transaction
4632 * recovery completion writes the changes to disk.
4633 */
4634struct xfs_btree_block_change_owner_info {
4635	uint64_t		new_owner;
4636	struct list_head	*buffer_list;
4637};
4638
4639static int
4640xfs_btree_block_change_owner(
4641	struct xfs_btree_cur	*cur,
4642	int			level,
4643	void			*data)
4644{
4645	struct xfs_btree_block_change_owner_info	*bbcoi = data;
4646	struct xfs_btree_block	*block;
4647	struct xfs_buf		*bp;
4648
4649	/* modify the owner */
4650	block = xfs_btree_get_block(cur, level, &bp);
4651	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN) {
4652		if (block->bb_u.l.bb_owner == cpu_to_be64(bbcoi->new_owner))
4653			return 0;
4654		block->bb_u.l.bb_owner = cpu_to_be64(bbcoi->new_owner);
4655	} else {
4656		if (block->bb_u.s.bb_owner == cpu_to_be32(bbcoi->new_owner))
4657			return 0;
4658		block->bb_u.s.bb_owner = cpu_to_be32(bbcoi->new_owner);
4659	}
4660
4661	/*
4662	 * If the block is a root block hosted in an inode, we might not have a
4663	 * buffer pointer here and we shouldn't attempt to log the change as the
4664	 * information is already held in the inode and discarded when the root
4665	 * block is formatted into the on-disk inode fork. We still change it,
4666	 * though, so everything is consistent in memory.
4667	 */
4668	if (!bp) {
4669		ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_INODE);
4670		ASSERT(level == cur->bc_nlevels - 1);
4671		return 0;
4672	}
4673
4674	if (cur->bc_tp) {
4675		if (!xfs_trans_ordered_buf(cur->bc_tp, bp)) {
4676			xfs_btree_log_block(cur, bp, XFS_BB_OWNER);
4677			return -EAGAIN;
4678		}
4679	} else {
4680		xfs_buf_delwri_queue(bp, bbcoi->buffer_list);
4681	}
4682
4683	return 0;
4684}
4685
4686int
4687xfs_btree_change_owner(
4688	struct xfs_btree_cur	*cur,
4689	uint64_t		new_owner,
4690	struct list_head	*buffer_list)
4691{
4692	struct xfs_btree_block_change_owner_info	bbcoi;
4693
4694	bbcoi.new_owner = new_owner;
4695	bbcoi.buffer_list = buffer_list;
4696
4697	return xfs_btree_visit_blocks(cur, xfs_btree_block_change_owner,
4698			XFS_BTREE_VISIT_ALL, &bbcoi);
4699}
4700
4701/* Verify the v5 fields of a long-format btree block. */
4702xfs_failaddr_t
4703xfs_btree_fsblock_v5hdr_verify(
4704	struct xfs_buf		*bp,
4705	uint64_t		owner)
4706{
4707	struct xfs_mount	*mp = bp->b_mount;
4708	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4709
4710	if (!xfs_has_crc(mp))
4711		return __this_address;
4712	if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
4713		return __this_address;
4714	if (block->bb_u.l.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4715		return __this_address;
4716	if (owner != XFS_RMAP_OWN_UNKNOWN &&
4717	    be64_to_cpu(block->bb_u.l.bb_owner) != owner)
4718		return __this_address;
4719	return NULL;
4720}
4721
4722/* Verify a long-format btree block. */
4723xfs_failaddr_t
4724xfs_btree_fsblock_verify(
4725	struct xfs_buf		*bp,
4726	unsigned int		max_recs)
4727{
4728	struct xfs_mount	*mp = bp->b_mount;
4729	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4730	xfs_fsblock_t		fsb;
4731	xfs_failaddr_t		fa;
4732
4733	ASSERT(!xfs_buftarg_is_mem(bp->b_target));
4734
4735	/* numrecs verification */
4736	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4737		return __this_address;
4738
4739	/* sibling pointer verification */
4740	fsb = XFS_DADDR_TO_FSB(mp, xfs_buf_daddr(bp));
4741	fa = xfs_btree_check_fsblock_siblings(mp, fsb,
4742			block->bb_u.l.bb_leftsib);
4743	if (!fa)
4744		fa = xfs_btree_check_fsblock_siblings(mp, fsb,
4745				block->bb_u.l.bb_rightsib);
4746	return fa;
4747}
4748
4749/* Verify an in-memory btree block. */
4750xfs_failaddr_t
4751xfs_btree_memblock_verify(
4752	struct xfs_buf		*bp,
4753	unsigned int		max_recs)
4754{
4755	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4756	struct xfs_buftarg	*btp = bp->b_target;
4757	xfs_failaddr_t		fa;
4758	xfbno_t			bno;
4759
4760	ASSERT(xfs_buftarg_is_mem(bp->b_target));
4761
4762	/* numrecs verification */
4763	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4764		return __this_address;
4765
4766	/* sibling pointer verification */
4767	bno = xfs_daddr_to_xfbno(xfs_buf_daddr(bp));
4768	fa = xfs_btree_check_memblock_siblings(btp, bno,
4769			block->bb_u.l.bb_leftsib);
4770	if (fa)
4771		return fa;
4772	fa = xfs_btree_check_memblock_siblings(btp, bno,
4773			block->bb_u.l.bb_rightsib);
4774	if (fa)
4775		return fa;
4776
4777	return NULL;
4778}
 
4779/**
4780 * xfs_btree_agblock_v5hdr_verify() -- verify the v5 fields of a short-format
4781 *				      btree block
4782 *
4783 * @bp: buffer containing the btree block
4784 */
4785xfs_failaddr_t
4786xfs_btree_agblock_v5hdr_verify(
4787	struct xfs_buf		*bp)
4788{
4789	struct xfs_mount	*mp = bp->b_mount;
4790	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4791	struct xfs_perag	*pag = bp->b_pag;
4792
4793	if (!xfs_has_crc(mp))
4794		return __this_address;
4795	if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
4796		return __this_address;
4797	if (block->bb_u.s.bb_blkno != cpu_to_be64(xfs_buf_daddr(bp)))
4798		return __this_address;
4799	if (pag && be32_to_cpu(block->bb_u.s.bb_owner) != pag->pag_agno)
4800		return __this_address;
4801	return NULL;
4802}
4803
4804/**
4805 * xfs_btree_agblock_verify() -- verify a short-format btree block
4806 *
4807 * @bp: buffer containing the btree block
4808 * @max_recs: maximum records allowed in this btree node
4809 */
4810xfs_failaddr_t
4811xfs_btree_agblock_verify(
4812	struct xfs_buf		*bp,
4813	unsigned int		max_recs)
4814{
4815	struct xfs_mount	*mp = bp->b_mount;
4816	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4817	xfs_agblock_t		agbno;
4818	xfs_failaddr_t		fa;
4819
4820	ASSERT(!xfs_buftarg_is_mem(bp->b_target));
4821
4822	/* numrecs verification */
4823	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4824		return __this_address;
4825
4826	/* sibling pointer verification */
4827	agbno = xfs_daddr_to_agbno(mp, xfs_buf_daddr(bp));
4828	fa = xfs_btree_check_agblock_siblings(bp->b_pag, agbno,
4829			block->bb_u.s.bb_leftsib);
4830	if (!fa)
4831		fa = xfs_btree_check_agblock_siblings(bp->b_pag, agbno,
4832				block->bb_u.s.bb_rightsib);
4833	return fa;
4834}
4835
4836/*
4837 * For the given limits on leaf and keyptr records per block, calculate the
4838 * height of the tree needed to index the number of leaf records.
4839 */
4840unsigned int
4841xfs_btree_compute_maxlevels(
4842	const unsigned int	*limits,
4843	unsigned long long	records)
4844{
4845	unsigned long long	level_blocks = howmany_64(records, limits[0]);
4846	unsigned int		height = 1;
4847
4848	while (level_blocks > 1) {
4849		level_blocks = howmany_64(level_blocks, limits[1]);
4850		height++;
4851	}
4852
4853	return height;
4854}
4855
4856/*
4857 * For the given limits on leaf and keyptr records per block, calculate the
4858 * number of blocks needed to index the given number of leaf records.
4859 */
4860unsigned long long
4861xfs_btree_calc_size(
4862	const unsigned int	*limits,
4863	unsigned long long	records)
4864{
4865	unsigned long long	level_blocks = howmany_64(records, limits[0]);
4866	unsigned long long	blocks = level_blocks;
4867
4868	while (level_blocks > 1) {
4869		level_blocks = howmany_64(level_blocks, limits[1]);
4870		blocks += level_blocks;
4871	}
4872
4873	return blocks;
4874}
4875
4876/*
4877 * Given a number of available blocks for the btree to consume with records and
4878 * pointers, calculate the height of the tree needed to index all the records
4879 * that space can hold based on the number of pointers each interior node
4880 * holds.
4881 *
4882 * We start by assuming a single level tree consumes a single block, then track
4883 * the number of blocks each node level consumes until we no longer have space
4884 * to store the next node level. At this point, we are indexing all the leaf
4885 * blocks in the space, and there's no more free space to split the tree any
4886 * further. That's our maximum btree height.
4887 */
4888unsigned int
4889xfs_btree_space_to_height(
4890	const unsigned int	*limits,
4891	unsigned long long	leaf_blocks)
4892{
4893	/*
4894	 * The root btree block can have fewer than minrecs pointers in it
4895	 * because the tree might not be big enough to require that amount of
4896	 * fanout. Hence it has a minimum size of 2 pointers, not limits[1].
4897	 */
4898	unsigned long long	node_blocks = 2;
4899	unsigned long long	blocks_left = leaf_blocks - 1;
4900	unsigned int		height = 1;
4901
4902	if (leaf_blocks < 1)
4903		return 0;
4904
4905	while (node_blocks < blocks_left) {
4906		blocks_left -= node_blocks;
4907		node_blocks *= limits[1];
4908		height++;
4909	}
4910
4911	return height;
4912}
4913
4914/*
4915 * Query a regular btree for all records overlapping a given interval.
4916 * Start with a LE lookup of the key of low_rec and return all records
4917 * until we find a record with a key greater than the key of high_rec.
4918 */
4919STATIC int
4920xfs_btree_simple_query_range(
4921	struct xfs_btree_cur		*cur,
4922	const union xfs_btree_key	*low_key,
4923	const union xfs_btree_key	*high_key,
4924	xfs_btree_query_range_fn	fn,
4925	void				*priv)
4926{
4927	union xfs_btree_rec		*recp;
4928	union xfs_btree_key		rec_key;
 
4929	int				stat;
4930	bool				firstrec = true;
4931	int				error;
4932
4933	ASSERT(cur->bc_ops->init_high_key_from_rec);
4934	ASSERT(cur->bc_ops->diff_two_keys);
4935
4936	/*
4937	 * Find the leftmost record.  The btree cursor must be set
4938	 * to the low record used to generate low_key.
4939	 */
4940	stat = 0;
4941	error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
4942	if (error)
4943		goto out;
4944
4945	/* Nothing?  See if there's anything to the right. */
4946	if (!stat) {
4947		error = xfs_btree_increment(cur, 0, &stat);
4948		if (error)
4949			goto out;
4950	}
4951
4952	while (stat) {
4953		/* Find the record. */
4954		error = xfs_btree_get_rec(cur, &recp, &stat);
4955		if (error || !stat)
4956			break;
4957
4958		/* Skip if low_key > high_key(rec). */
4959		if (firstrec) {
4960			cur->bc_ops->init_high_key_from_rec(&rec_key, recp);
4961			firstrec = false;
4962			if (xfs_btree_keycmp_gt(cur, low_key, &rec_key))
 
 
4963				goto advloop;
4964		}
4965
4966		/* Stop if low_key(rec) > high_key. */
4967		cur->bc_ops->init_key_from_rec(&rec_key, recp);
4968		if (xfs_btree_keycmp_gt(cur, &rec_key, high_key))
 
4969			break;
4970
4971		/* Callback */
4972		error = fn(cur, recp, priv);
4973		if (error)
4974			break;
4975
4976advloop:
4977		/* Move on to the next record. */
4978		error = xfs_btree_increment(cur, 0, &stat);
4979		if (error)
4980			break;
4981	}
4982
4983out:
4984	return error;
4985}
4986
4987/*
4988 * Query an overlapped interval btree for all records overlapping a given
4989 * interval.  This function roughly follows the algorithm given in
4990 * "Interval Trees" of _Introduction to Algorithms_, which is section
4991 * 14.3 in the 2nd and 3rd editions.
4992 *
4993 * First, generate keys for the low and high records passed in.
4994 *
4995 * For any leaf node, generate the high and low keys for the record.
4996 * If the record keys overlap with the query low/high keys, pass the
4997 * record to the function iterator.
4998 *
4999 * For any internal node, compare the low and high keys of each
5000 * pointer against the query low/high keys.  If there's an overlap,
5001 * follow the pointer.
5002 *
5003 * As an optimization, we stop scanning a block when we find a low key
5004 * that is greater than the query's high key.
5005 */
5006STATIC int
5007xfs_btree_overlapped_query_range(
5008	struct xfs_btree_cur		*cur,
5009	const union xfs_btree_key	*low_key,
5010	const union xfs_btree_key	*high_key,
5011	xfs_btree_query_range_fn	fn,
5012	void				*priv)
5013{
5014	union xfs_btree_ptr		ptr;
5015	union xfs_btree_ptr		*pp;
5016	union xfs_btree_key		rec_key;
5017	union xfs_btree_key		rec_hkey;
5018	union xfs_btree_key		*lkp;
5019	union xfs_btree_key		*hkp;
5020	union xfs_btree_rec		*recp;
5021	struct xfs_btree_block		*block;
 
 
5022	int				level;
5023	struct xfs_buf			*bp;
5024	int				i;
5025	int				error;
5026
5027	/* Load the root of the btree. */
5028	level = cur->bc_nlevels - 1;
5029	xfs_btree_init_ptr_from_cur(cur, &ptr);
5030	error = xfs_btree_lookup_get_block(cur, level, &ptr, &block);
5031	if (error)
5032		return error;
5033	xfs_btree_get_block(cur, level, &bp);
5034	trace_xfs_btree_overlapped_query_range(cur, level, bp);
5035#ifdef DEBUG
5036	error = xfs_btree_check_block(cur, block, level, bp);
5037	if (error)
5038		goto out;
5039#endif
5040	cur->bc_levels[level].ptr = 1;
5041
5042	while (level < cur->bc_nlevels) {
5043		block = xfs_btree_get_block(cur, level, &bp);
5044
5045		/* End of node, pop back towards the root. */
5046		if (cur->bc_levels[level].ptr >
5047					be16_to_cpu(block->bb_numrecs)) {
5048pop_up:
5049			if (level < cur->bc_nlevels - 1)
5050				cur->bc_levels[level + 1].ptr++;
5051			level++;
5052			continue;
5053		}
5054
5055		if (level == 0) {
5056			/* Handle a leaf node. */
5057			recp = xfs_btree_rec_addr(cur, cur->bc_levels[0].ptr,
5058					block);
5059
5060			cur->bc_ops->init_high_key_from_rec(&rec_hkey, recp);
 
 
 
5061			cur->bc_ops->init_key_from_rec(&rec_key, recp);
 
 
5062
5063			/*
5064			 * If (query's high key < record's low key), then there
5065			 * are no more interesting records in this block.  Pop
5066			 * up to the leaf level to find more record blocks.
5067			 *
5068			 * If (record's high key >= query's low key) and
5069			 *    (query's high key >= record's low key), then
5070			 * this record overlaps the query range; callback.
5071			 */
5072			if (xfs_btree_keycmp_lt(cur, high_key, &rec_key))
5073				goto pop_up;
5074			if (xfs_btree_keycmp_ge(cur, &rec_hkey, low_key)) {
5075				error = fn(cur, recp, priv);
5076				if (error)
5077					break;
 
 
 
5078			}
5079			cur->bc_levels[level].ptr++;
5080			continue;
5081		}
5082
5083		/* Handle an internal node. */
5084		lkp = xfs_btree_key_addr(cur, cur->bc_levels[level].ptr, block);
5085		hkp = xfs_btree_high_key_addr(cur, cur->bc_levels[level].ptr,
5086				block);
5087		pp = xfs_btree_ptr_addr(cur, cur->bc_levels[level].ptr, block);
 
 
5088
5089		/*
5090		 * If (query's high key < pointer's low key), then there are no
5091		 * more interesting keys in this block.  Pop up one leaf level
5092		 * to continue looking for records.
5093		 *
5094		 * If (pointer's high key >= query's low key) and
5095		 *    (query's high key >= pointer's low key), then
5096		 * this record overlaps the query range; follow pointer.
5097		 */
5098		if (xfs_btree_keycmp_lt(cur, high_key, lkp))
5099			goto pop_up;
5100		if (xfs_btree_keycmp_ge(cur, hkp, low_key)) {
5101			level--;
5102			error = xfs_btree_lookup_get_block(cur, level, pp,
5103					&block);
5104			if (error)
5105				goto out;
5106			xfs_btree_get_block(cur, level, &bp);
5107			trace_xfs_btree_overlapped_query_range(cur, level, bp);
5108#ifdef DEBUG
5109			error = xfs_btree_check_block(cur, block, level, bp);
5110			if (error)
5111				goto out;
5112#endif
5113			cur->bc_levels[level].ptr = 1;
5114			continue;
 
 
 
5115		}
5116		cur->bc_levels[level].ptr++;
5117	}
5118
5119out:
5120	/*
5121	 * If we don't end this function with the cursor pointing at a record
5122	 * block, a subsequent non-error cursor deletion will not release
5123	 * node-level buffers, causing a buffer leak.  This is quite possible
5124	 * with a zero-results range query, so release the buffers if we
5125	 * failed to return any results.
5126	 */
5127	if (cur->bc_levels[0].bp == NULL) {
5128		for (i = 0; i < cur->bc_nlevels; i++) {
5129			if (cur->bc_levels[i].bp) {
5130				xfs_trans_brelse(cur->bc_tp,
5131						cur->bc_levels[i].bp);
5132				cur->bc_levels[i].bp = NULL;
5133				cur->bc_levels[i].ptr = 0;
5134				cur->bc_levels[i].ra = 0;
5135			}
5136		}
5137	}
5138
5139	return error;
5140}
5141
5142static inline void
5143xfs_btree_key_from_irec(
5144	struct xfs_btree_cur		*cur,
5145	union xfs_btree_key		*key,
5146	const union xfs_btree_irec	*irec)
5147{
5148	union xfs_btree_rec		rec;
5149
5150	cur->bc_rec = *irec;
5151	cur->bc_ops->init_rec_from_cur(cur, &rec);
5152	cur->bc_ops->init_key_from_rec(key, &rec);
5153}
5154
5155/*
5156 * Query a btree for all records overlapping a given interval of keys.  The
5157 * supplied function will be called with each record found; return one of the
5158 * XFS_BTREE_QUERY_RANGE_{CONTINUE,ABORT} values or the usual negative error
5159 * code.  This function returns -ECANCELED, zero, or a negative error code.
5160 */
5161int
5162xfs_btree_query_range(
5163	struct xfs_btree_cur		*cur,
5164	const union xfs_btree_irec	*low_rec,
5165	const union xfs_btree_irec	*high_rec,
5166	xfs_btree_query_range_fn	fn,
5167	void				*priv)
5168{
 
5169	union xfs_btree_key		low_key;
5170	union xfs_btree_key		high_key;
5171
5172	/* Find the keys of both ends of the interval. */
5173	xfs_btree_key_from_irec(cur, &high_key, high_rec);
5174	xfs_btree_key_from_irec(cur, &low_key, low_rec);
 
 
 
 
 
5175
5176	/* Enforce low key <= high key. */
5177	if (!xfs_btree_keycmp_le(cur, &low_key, &high_key))
5178		return -EINVAL;
5179
5180	if (!(cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING))
5181		return xfs_btree_simple_query_range(cur, &low_key,
5182				&high_key, fn, priv);
5183	return xfs_btree_overlapped_query_range(cur, &low_key, &high_key,
5184			fn, priv);
5185}
5186
5187/* Query a btree for all records. */
5188int
5189xfs_btree_query_all(
5190	struct xfs_btree_cur		*cur,
5191	xfs_btree_query_range_fn	fn,
5192	void				*priv)
5193{
5194	union xfs_btree_key		low_key;
5195	union xfs_btree_key		high_key;
5196
5197	memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
5198	memset(&low_key, 0, sizeof(low_key));
5199	memset(&high_key, 0xFF, sizeof(high_key));
5200
5201	return xfs_btree_simple_query_range(cur, &low_key, &high_key, fn, priv);
5202}
5203
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5204static int
5205xfs_btree_count_blocks_helper(
5206	struct xfs_btree_cur	*cur,
5207	int			level,
5208	void			*data)
5209{
5210	xfs_extlen_t		*blocks = data;
5211	(*blocks)++;
5212
5213	return 0;
5214}
5215
5216/* Count the blocks in a btree and return the result in *blocks. */
5217int
5218xfs_btree_count_blocks(
5219	struct xfs_btree_cur	*cur,
5220	xfs_extlen_t		*blocks)
5221{
5222	*blocks = 0;
5223	return xfs_btree_visit_blocks(cur, xfs_btree_count_blocks_helper,
5224			XFS_BTREE_VISIT_ALL, blocks);
5225}
5226
5227/* Compare two btree pointers. */
5228int64_t
5229xfs_btree_diff_two_ptrs(
5230	struct xfs_btree_cur		*cur,
5231	const union xfs_btree_ptr	*a,
5232	const union xfs_btree_ptr	*b)
5233{
5234	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
5235		return (int64_t)be64_to_cpu(a->l) - be64_to_cpu(b->l);
5236	return (int64_t)be32_to_cpu(a->s) - be32_to_cpu(b->s);
5237}
5238
5239struct xfs_btree_has_records {
5240	/* Keys for the start and end of the range we want to know about. */
5241	union xfs_btree_key		start_key;
5242	union xfs_btree_key		end_key;
5243
5244	/* Mask for key comparisons, if desired. */
5245	const union xfs_btree_key	*key_mask;
5246
5247	/* Highest record key we've seen so far. */
5248	union xfs_btree_key		high_key;
5249
5250	enum xbtree_recpacking		outcome;
5251};
5252
5253STATIC int
5254xfs_btree_has_records_helper(
5255	struct xfs_btree_cur		*cur,
5256	const union xfs_btree_rec	*rec,
5257	void				*priv)
5258{
5259	union xfs_btree_key		rec_key;
5260	union xfs_btree_key		rec_high_key;
5261	struct xfs_btree_has_records	*info = priv;
5262	enum xbtree_key_contig		key_contig;
5263
5264	cur->bc_ops->init_key_from_rec(&rec_key, rec);
5265
5266	if (info->outcome == XBTREE_RECPACKING_EMPTY) {
5267		info->outcome = XBTREE_RECPACKING_SPARSE;
5268
5269		/*
5270		 * If the first record we find does not overlap the start key,
5271		 * then there is a hole at the start of the search range.
5272		 * Classify this as sparse and stop immediately.
5273		 */
5274		if (xfs_btree_masked_keycmp_lt(cur, &info->start_key, &rec_key,
5275					info->key_mask))
5276			return -ECANCELED;
5277	} else {
5278		/*
5279		 * If a subsequent record does not overlap with the any record
5280		 * we've seen so far, there is a hole in the middle of the
5281		 * search range.  Classify this as sparse and stop.
5282		 * If the keys overlap and this btree does not allow overlap,
5283		 * signal corruption.
5284		 */
5285		key_contig = cur->bc_ops->keys_contiguous(cur, &info->high_key,
5286					&rec_key, info->key_mask);
5287		if (key_contig == XBTREE_KEY_OVERLAP &&
5288				!(cur->bc_ops->geom_flags & XFS_BTGEO_OVERLAPPING))
5289			return -EFSCORRUPTED;
5290		if (key_contig == XBTREE_KEY_GAP)
5291			return -ECANCELED;
5292	}
5293
5294	/*
5295	 * If high_key(rec) is larger than any other high key we've seen,
5296	 * remember it for later.
5297	 */
5298	cur->bc_ops->init_high_key_from_rec(&rec_high_key, rec);
5299	if (xfs_btree_masked_keycmp_gt(cur, &rec_high_key, &info->high_key,
5300				info->key_mask))
5301		info->high_key = rec_high_key; /* struct copy */
5302
5303	return 0;
5304}
5305
5306/*
5307 * Scan part of the keyspace of a btree and tell us if that keyspace does not
5308 * map to any records; is fully mapped to records; or is partially mapped to
5309 * records.  This is the btree record equivalent to determining if a file is
5310 * sparse.
5311 *
5312 * For most btree types, the record scan should use all available btree key
5313 * fields to compare the keys encountered.  These callers should pass NULL for
5314 * @mask.  However, some callers (e.g.  scanning physical space in the rmapbt)
5315 * want to ignore some part of the btree record keyspace when performing the
5316 * comparison.  These callers should pass in a union xfs_btree_key object with
5317 * the fields that *should* be a part of the comparison set to any nonzero
5318 * value, and the rest zeroed.
5319 */
5320int
5321xfs_btree_has_records(
5322	struct xfs_btree_cur		*cur,
5323	const union xfs_btree_irec	*low,
5324	const union xfs_btree_irec	*high,
5325	const union xfs_btree_key	*mask,
5326	enum xbtree_recpacking		*outcome)
5327{
5328	struct xfs_btree_has_records	info = {
5329		.outcome		= XBTREE_RECPACKING_EMPTY,
5330		.key_mask		= mask,
5331	};
5332	int				error;
5333
5334	/* Not all btrees support this operation. */
5335	if (!cur->bc_ops->keys_contiguous) {
5336		ASSERT(0);
5337		return -EOPNOTSUPP;
5338	}
5339
5340	xfs_btree_key_from_irec(cur, &info.start_key, low);
5341	xfs_btree_key_from_irec(cur, &info.end_key, high);
5342
5343	error = xfs_btree_query_range(cur, low, high,
5344			xfs_btree_has_records_helper, &info);
5345	if (error == -ECANCELED)
5346		goto out;
5347	if (error)
5348		return error;
5349
5350	if (info.outcome == XBTREE_RECPACKING_EMPTY)
5351		goto out;
5352
5353	/*
5354	 * If the largest high_key(rec) we saw during the walk is greater than
5355	 * the end of the search range, classify this as full.  Otherwise,
5356	 * there is a hole at the end of the search range.
5357	 */
5358	if (xfs_btree_masked_keycmp_ge(cur, &info.high_key, &info.end_key,
5359				mask))
5360		info.outcome = XBTREE_RECPACKING_FULL;
5361
5362out:
5363	*outcome = info.outcome;
5364	return 0;
5365}
5366
5367/* Are there more records in this btree? */
5368bool
5369xfs_btree_has_more_records(
5370	struct xfs_btree_cur	*cur)
5371{
5372	struct xfs_btree_block	*block;
5373	struct xfs_buf		*bp;
5374
5375	block = xfs_btree_get_block(cur, 0, &bp);
5376
5377	/* There are still records in this block. */
5378	if (cur->bc_levels[0].ptr < xfs_btree_get_numrecs(block))
5379		return true;
5380
5381	/* There are more record blocks. */
5382	if (cur->bc_ops->ptr_len == XFS_BTREE_LONG_PTR_LEN)
5383		return block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK);
5384	else
5385		return block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK);
5386}
5387
5388/* Set up all the btree cursor caches. */
5389int __init
5390xfs_btree_init_cur_caches(void)
5391{
5392	int		error;
5393
5394	error = xfs_allocbt_init_cur_cache();
5395	if (error)
5396		return error;
5397	error = xfs_inobt_init_cur_cache();
5398	if (error)
5399		goto err;
5400	error = xfs_bmbt_init_cur_cache();
5401	if (error)
5402		goto err;
5403	error = xfs_rmapbt_init_cur_cache();
5404	if (error)
5405		goto err;
5406	error = xfs_refcountbt_init_cur_cache();
5407	if (error)
5408		goto err;
5409
5410	return 0;
5411err:
5412	xfs_btree_destroy_cur_caches();
5413	return error;
5414}
5415
5416/* Destroy all the btree cursor caches, if they've been allocated. */
5417void
5418xfs_btree_destroy_cur_caches(void)
5419{
5420	xfs_allocbt_destroy_cur_cache();
5421	xfs_inobt_destroy_cur_cache();
5422	xfs_bmbt_destroy_cur_cache();
5423	xfs_rmapbt_destroy_cur_cache();
5424	xfs_refcountbt_destroy_cur_cache();
5425}
5426
5427/* Move the btree cursor before the first record. */
5428int
5429xfs_btree_goto_left_edge(
5430	struct xfs_btree_cur	*cur)
5431{
5432	int			stat = 0;
5433	int			error;
5434
5435	memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
5436	error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
5437	if (error)
5438		return error;
5439	if (!stat)
5440		return 0;
5441
5442	error = xfs_btree_decrement(cur, 0, &stat);
5443	if (error)
5444		return error;
5445	if (stat != 0) {
5446		ASSERT(0);
5447		xfs_btree_mark_sick(cur);
5448		return -EFSCORRUPTED;
5449	}
5450
5451	return 0;
5452}