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
  25/*
  26 * Cursor allocation zone.
  27 */
  28kmem_zone_t	*xfs_btree_cur_zone;
  29
  30/*
  31 * Btree magic numbers.
  32 */
  33static const uint32_t xfs_magics[2][XFS_BTNUM_MAX] = {
  34	{ XFS_ABTB_MAGIC, XFS_ABTC_MAGIC, 0, XFS_BMAP_MAGIC, XFS_IBT_MAGIC,
  35	  XFS_FIBT_MAGIC, 0 },
  36	{ XFS_ABTB_CRC_MAGIC, XFS_ABTC_CRC_MAGIC, XFS_RMAP_CRC_MAGIC,
  37	  XFS_BMAP_CRC_MAGIC, XFS_IBT_CRC_MAGIC, XFS_FIBT_CRC_MAGIC,
  38	  XFS_REFC_CRC_MAGIC }
  39};
  40
  41uint32_t
  42xfs_btree_magic(
  43	int			crc,
  44	xfs_btnum_t		btnum)
  45{
  46	uint32_t		magic = xfs_magics[crc][btnum];
  47
  48	/* Ensure we asked for crc for crc-only magics. */
  49	ASSERT(magic != 0);
  50	return magic;
  51}
  52
  53/*
  54 * Check a long btree block header.  Return the address of the failing check,
  55 * or NULL if everything is ok.
  56 */
  57xfs_failaddr_t
  58__xfs_btree_check_lblock(
  59	struct xfs_btree_cur	*cur,
  60	struct xfs_btree_block	*block,
  61	int			level,
  62	struct xfs_buf		*bp)
  63{
  64	struct xfs_mount	*mp = cur->bc_mp;
  65	xfs_btnum_t		btnum = cur->bc_btnum;
  66	int			crc = xfs_sb_version_hascrc(&mp->m_sb);
  67
  68	if (crc) {
  69		if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
  70			return __this_address;
  71		if (block->bb_u.l.bb_blkno !=
  72		    cpu_to_be64(bp ? bp->b_bn : XFS_BUF_DADDR_NULL))
  73			return __this_address;
  74		if (block->bb_u.l.bb_pad != cpu_to_be32(0))
  75			return __this_address;
  76	}
  77
  78	if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
  79		return __this_address;
  80	if (be16_to_cpu(block->bb_level) != level)
  81		return __this_address;
  82	if (be16_to_cpu(block->bb_numrecs) >
  83	    cur->bc_ops->get_maxrecs(cur, level))
  84		return __this_address;
  85	if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK) &&
  86	    !xfs_btree_check_lptr(cur, be64_to_cpu(block->bb_u.l.bb_leftsib),
  87			level + 1))
  88		return __this_address;
  89	if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK) &&
  90	    !xfs_btree_check_lptr(cur, be64_to_cpu(block->bb_u.l.bb_rightsib),
  91			level + 1))
  92		return __this_address;
  93
  94	return NULL;
  95}
  96
  97/* Check a long btree block header. */
  98static int
  99xfs_btree_check_lblock(
 100	struct xfs_btree_cur	*cur,
 101	struct xfs_btree_block	*block,
 102	int			level,
 103	struct xfs_buf		*bp)
 104{
 105	struct xfs_mount	*mp = cur->bc_mp;
 106	xfs_failaddr_t		fa;
 107
 108	fa = __xfs_btree_check_lblock(cur, block, level, bp);
 109	if (XFS_IS_CORRUPT(mp, fa != NULL) ||
 110	    XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BTREE_CHECK_LBLOCK)) {
 111		if (bp)
 112			trace_xfs_btree_corrupt(bp, _RET_IP_);
 113		return -EFSCORRUPTED;
 114	}
 115	return 0;
 116}
 117
 118/*
 119 * Check a short btree block header.  Return the address of the failing check,
 120 * or NULL if everything is ok.
 121 */
 122xfs_failaddr_t
 123__xfs_btree_check_sblock(
 124	struct xfs_btree_cur	*cur,
 125	struct xfs_btree_block	*block,
 126	int			level,
 127	struct xfs_buf		*bp)
 128{
 129	struct xfs_mount	*mp = cur->bc_mp;
 130	xfs_btnum_t		btnum = cur->bc_btnum;
 131	int			crc = xfs_sb_version_hascrc(&mp->m_sb);
 132
 133	if (crc) {
 134		if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
 135			return __this_address;
 136		if (block->bb_u.s.bb_blkno !=
 137		    cpu_to_be64(bp ? bp->b_bn : XFS_BUF_DADDR_NULL))
 138			return __this_address;
 139	}
 140
 141	if (be32_to_cpu(block->bb_magic) != xfs_btree_magic(crc, btnum))
 142		return __this_address;
 143	if (be16_to_cpu(block->bb_level) != level)
 144		return __this_address;
 145	if (be16_to_cpu(block->bb_numrecs) >
 146	    cur->bc_ops->get_maxrecs(cur, level))
 147		return __this_address;
 148	if (block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK) &&
 149	    !xfs_btree_check_sptr(cur, be32_to_cpu(block->bb_u.s.bb_leftsib),
 150			level + 1))
 151		return __this_address;
 152	if (block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK) &&
 153	    !xfs_btree_check_sptr(cur, be32_to_cpu(block->bb_u.s.bb_rightsib),
 154			level + 1))
 155		return __this_address;
 156
 157	return NULL;
 158}
 159
 160/* Check a short btree block header. */
 161STATIC int
 162xfs_btree_check_sblock(
 163	struct xfs_btree_cur	*cur,
 164	struct xfs_btree_block	*block,
 165	int			level,
 166	struct xfs_buf		*bp)
 167{
 168	struct xfs_mount	*mp = cur->bc_mp;
 169	xfs_failaddr_t		fa;
 170
 171	fa = __xfs_btree_check_sblock(cur, block, level, bp);
 172	if (XFS_IS_CORRUPT(mp, fa != NULL) ||
 173	    XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BTREE_CHECK_SBLOCK)) {
 174		if (bp)
 175			trace_xfs_btree_corrupt(bp, _RET_IP_);
 176		return -EFSCORRUPTED;
 177	}
 178	return 0;
 179}
 180
 181/*
 182 * Debug routine: check that block header is ok.
 183 */
 184int
 185xfs_btree_check_block(
 186	struct xfs_btree_cur	*cur,	/* btree cursor */
 187	struct xfs_btree_block	*block,	/* generic btree block pointer */
 188	int			level,	/* level of the btree block */
 189	struct xfs_buf		*bp)	/* buffer containing block, if any */
 190{
 191	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 192		return xfs_btree_check_lblock(cur, block, level, bp);
 193	else
 194		return xfs_btree_check_sblock(cur, block, level, bp);
 195}
 196
 197/* Check that this long pointer is valid and points within the fs. */
 198bool
 199xfs_btree_check_lptr(
 200	struct xfs_btree_cur	*cur,
 201	xfs_fsblock_t		fsbno,
 202	int			level)
 203{
 204	if (level <= 0)
 205		return false;
 206	return xfs_verify_fsbno(cur->bc_mp, fsbno);
 207}
 208
 209/* Check that this short pointer is valid and points within the AG. */
 210bool
 211xfs_btree_check_sptr(
 212	struct xfs_btree_cur	*cur,
 213	xfs_agblock_t		agbno,
 214	int			level)
 215{
 216	if (level <= 0)
 217		return false;
 218	return xfs_verify_agbno(cur->bc_mp, cur->bc_ag.agno, agbno);
 219}
 220
 221/*
 222 * Check that a given (indexed) btree pointer at a certain level of a
 223 * btree is valid and doesn't point past where it should.
 224 */
 225static int
 226xfs_btree_check_ptr(
 227	struct xfs_btree_cur	*cur,
 228	union xfs_btree_ptr	*ptr,
 229	int			index,
 230	int			level)
 231{
 232	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 233		if (xfs_btree_check_lptr(cur, be64_to_cpu((&ptr->l)[index]),
 234				level))
 235			return 0;
 236		xfs_err(cur->bc_mp,
 237"Inode %llu fork %d: Corrupt btree %d pointer at level %d index %d.",
 238				cur->bc_ino.ip->i_ino,
 239				cur->bc_ino.whichfork, cur->bc_btnum,
 240				level, index);
 241	} else {
 242		if (xfs_btree_check_sptr(cur, be32_to_cpu((&ptr->s)[index]),
 243				level))
 244			return 0;
 245		xfs_err(cur->bc_mp,
 246"AG %u: Corrupt btree %d pointer at level %d index %d.",
 247				cur->bc_ag.agno, cur->bc_btnum,
 248				level, index);
 249	}
 250
 251	return -EFSCORRUPTED;
 252}
 253
 254#ifdef DEBUG
 255# define xfs_btree_debug_check_ptr	xfs_btree_check_ptr
 256#else
 257# define xfs_btree_debug_check_ptr(...)	(0)
 258#endif
 259
 260/*
 261 * Calculate CRC on the whole btree block and stuff it into the
 262 * long-form btree header.
 263 *
 264 * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
 265 * it into the buffer so recovery knows what the last modification was that made
 266 * it to disk.
 267 */
 268void
 269xfs_btree_lblock_calc_crc(
 270	struct xfs_buf		*bp)
 271{
 272	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
 273	struct xfs_buf_log_item	*bip = bp->b_log_item;
 274
 275	if (!xfs_sb_version_hascrc(&bp->b_mount->m_sb))
 276		return;
 277	if (bip)
 278		block->bb_u.l.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
 279	xfs_buf_update_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
 280}
 281
 282bool
 283xfs_btree_lblock_verify_crc(
 284	struct xfs_buf		*bp)
 285{
 286	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
 287	struct xfs_mount	*mp = bp->b_mount;
 288
 289	if (xfs_sb_version_hascrc(&mp->m_sb)) {
 290		if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.l.bb_lsn)))
 291			return false;
 292		return xfs_buf_verify_cksum(bp, XFS_BTREE_LBLOCK_CRC_OFF);
 293	}
 294
 295	return true;
 296}
 297
 298/*
 299 * Calculate CRC on the whole btree block and stuff it into the
 300 * short-form btree header.
 301 *
 302 * Prior to calculting the CRC, pull the LSN out of the buffer log item and put
 303 * it into the buffer so recovery knows what the last modification was that made
 304 * it to disk.
 305 */
 306void
 307xfs_btree_sblock_calc_crc(
 308	struct xfs_buf		*bp)
 309{
 310	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
 311	struct xfs_buf_log_item	*bip = bp->b_log_item;
 312
 313	if (!xfs_sb_version_hascrc(&bp->b_mount->m_sb))
 314		return;
 315	if (bip)
 316		block->bb_u.s.bb_lsn = cpu_to_be64(bip->bli_item.li_lsn);
 317	xfs_buf_update_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
 318}
 319
 320bool
 321xfs_btree_sblock_verify_crc(
 322	struct xfs_buf		*bp)
 323{
 324	struct xfs_btree_block  *block = XFS_BUF_TO_BLOCK(bp);
 325	struct xfs_mount	*mp = bp->b_mount;
 326
 327	if (xfs_sb_version_hascrc(&mp->m_sb)) {
 328		if (!xfs_log_check_lsn(mp, be64_to_cpu(block->bb_u.s.bb_lsn)))
 329			return false;
 330		return xfs_buf_verify_cksum(bp, XFS_BTREE_SBLOCK_CRC_OFF);
 331	}
 332
 333	return true;
 334}
 335
 336static int
 337xfs_btree_free_block(
 338	struct xfs_btree_cur	*cur,
 339	struct xfs_buf		*bp)
 340{
 341	int			error;
 342
 343	error = cur->bc_ops->free_block(cur, bp);
 344	if (!error) {
 345		xfs_trans_binval(cur->bc_tp, bp);
 346		XFS_BTREE_STATS_INC(cur, free);
 347	}
 348	return error;
 349}
 350
 351/*
 352 * Delete the btree cursor.
 353 */
 354void
 355xfs_btree_del_cursor(
 356	xfs_btree_cur_t	*cur,		/* btree cursor */
 357	int		error)		/* del because of error */
 358{
 359	int		i;		/* btree level */
 360
 361	/*
 362	 * Clear the buffer pointers, and release the buffers.
 363	 * If we're doing this in the face of an error, we
 364	 * need to make sure to inspect all of the entries
 365	 * in the bc_bufs array for buffers to be unlocked.
 366	 * This is because some of the btree code works from
 367	 * level n down to 0, and if we get an error along
 368	 * the way we won't have initialized all the entries
 369	 * down to 0.
 370	 */
 371	for (i = 0; i < cur->bc_nlevels; i++) {
 372		if (cur->bc_bufs[i])
 373			xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[i]);
 374		else if (!error)
 375			break;
 376	}
 377	/*
 378	 * Can't free a bmap cursor without having dealt with the
 379	 * allocated indirect blocks' accounting.
 380	 */
 381	ASSERT(cur->bc_btnum != XFS_BTNUM_BMAP ||
 382	       cur->bc_ino.allocated == 0);
 383	/*
 384	 * Free the cursor.
 385	 */
 386	if (unlikely(cur->bc_flags & XFS_BTREE_STAGING))
 387		kmem_free((void *)cur->bc_ops);
 388	kmem_cache_free(xfs_btree_cur_zone, cur);
 389}
 390
 391/*
 392 * Duplicate the btree cursor.
 393 * Allocate a new one, copy the record, re-get the buffers.
 394 */
 395int					/* error */
 396xfs_btree_dup_cursor(
 397	xfs_btree_cur_t	*cur,		/* input cursor */
 398	xfs_btree_cur_t	**ncur)		/* output cursor */
 399{
 400	xfs_buf_t	*bp;		/* btree block's buffer pointer */
 401	int		error;		/* error return value */
 402	int		i;		/* level number of btree block */
 403	xfs_mount_t	*mp;		/* mount structure for filesystem */
 404	xfs_btree_cur_t	*new;		/* new cursor value */
 405	xfs_trans_t	*tp;		/* transaction pointer, can be NULL */
 406
 407	tp = cur->bc_tp;
 408	mp = cur->bc_mp;
 409
 410	/*
 411	 * Allocate a new cursor like the old one.
 412	 */
 413	new = cur->bc_ops->dup_cursor(cur);
 414
 415	/*
 416	 * Copy the record currently in the cursor.
 417	 */
 418	new->bc_rec = cur->bc_rec;
 419
 420	/*
 421	 * For each level current, re-get the buffer and copy the ptr value.
 422	 */
 423	for (i = 0; i < new->bc_nlevels; i++) {
 424		new->bc_ptrs[i] = cur->bc_ptrs[i];
 425		new->bc_ra[i] = cur->bc_ra[i];
 426		bp = cur->bc_bufs[i];
 427		if (bp) {
 428			error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
 429						   XFS_BUF_ADDR(bp), mp->m_bsize,
 430						   0, &bp,
 431						   cur->bc_ops->buf_ops);
 432			if (error) {
 433				xfs_btree_del_cursor(new, error);
 434				*ncur = NULL;
 435				return error;
 436			}
 437		}
 438		new->bc_bufs[i] = bp;
 439	}
 440	*ncur = new;
 441	return 0;
 442}
 443
 444/*
 445 * XFS btree block layout and addressing:
 446 *
 447 * There are two types of blocks in the btree: leaf and non-leaf blocks.
 448 *
 449 * The leaf record start with a header then followed by records containing
 450 * the values.  A non-leaf block also starts with the same header, and
 451 * then first contains lookup keys followed by an equal number of pointers
 452 * to the btree blocks at the previous level.
 453 *
 454 *		+--------+-------+-------+-------+-------+-------+-------+
 455 * Leaf:	| header | rec 1 | rec 2 | rec 3 | rec 4 | rec 5 | rec N |
 456 *		+--------+-------+-------+-------+-------+-------+-------+
 457 *
 458 *		+--------+-------+-------+-------+-------+-------+-------+
 459 * Non-Leaf:	| header | key 1 | key 2 | key N | ptr 1 | ptr 2 | ptr N |
 460 *		+--------+-------+-------+-------+-------+-------+-------+
 461 *
 462 * The header is called struct xfs_btree_block for reasons better left unknown
 463 * and comes in different versions for short (32bit) and long (64bit) block
 464 * pointers.  The record and key structures are defined by the btree instances
 465 * and opaque to the btree core.  The block pointers are simple disk endian
 466 * integers, available in a short (32bit) and long (64bit) variant.
 467 *
 468 * The helpers below calculate the offset of a given record, key or pointer
 469 * into a btree block (xfs_btree_*_offset) or return a pointer to the given
 470 * record, key or pointer (xfs_btree_*_addr).  Note that all addressing
 471 * inside the btree block is done using indices starting at one, not zero!
 472 *
 473 * If XFS_BTREE_OVERLAPPING is set, then this btree supports keys containing
 474 * overlapping intervals.  In such a tree, records are still sorted lowest to
 475 * highest and indexed by the smallest key value that refers to the record.
 476 * However, nodes are different: each pointer has two associated keys -- one
 477 * indexing the lowest key available in the block(s) below (the same behavior
 478 * as the key in a regular btree) and another indexing the highest key
 479 * available in the block(s) below.  Because records are /not/ sorted by the
 480 * highest key, all leaf block updates require us to compute the highest key
 481 * that matches any record in the leaf and to recursively update the high keys
 482 * in the nodes going further up in the tree, if necessary.  Nodes look like
 483 * this:
 484 *
 485 *		+--------+-----+-----+-----+-----+-----+-------+-------+-----+
 486 * Non-Leaf:	| header | lo1 | hi1 | lo2 | hi2 | ... | ptr 1 | ptr 2 | ... |
 487 *		+--------+-----+-----+-----+-----+-----+-------+-------+-----+
 488 *
 489 * To perform an interval query on an overlapped tree, perform the usual
 490 * depth-first search and use the low and high keys to decide if we can skip
 491 * that particular node.  If a leaf node is reached, return the records that
 492 * intersect the interval.  Note that an interval query may return numerous
 493 * entries.  For a non-overlapped tree, simply search for the record associated
 494 * with the lowest key and iterate forward until a non-matching record is
 495 * found.  Section 14.3 ("Interval Trees") of _Introduction to Algorithms_ by
 496 * Cormen, Leiserson, Rivest, and Stein (2nd or 3rd ed. only) discuss this in
 497 * more detail.
 498 *
 499 * Why do we care about overlapping intervals?  Let's say you have a bunch of
 500 * reverse mapping records on a reflink filesystem:
 501 *
 502 * 1: +- file A startblock B offset C length D -----------+
 503 * 2:      +- file E startblock F offset G length H --------------+
 504 * 3:      +- file I startblock F offset J length K --+
 505 * 4:                                                        +- file L... --+
 506 *
 507 * Now say we want to map block (B+D) into file A at offset (C+D).  Ideally,
 508 * we'd simply increment the length of record 1.  But how do we find the record
 509 * that ends at (B+D-1) (i.e. record 1)?  A LE lookup of (B+D-1) would return
 510 * record 3 because the keys are ordered first by startblock.  An interval
 511 * query would return records 1 and 2 because they both overlap (B+D-1), and
 512 * from that we can pick out record 1 as the appropriate left neighbor.
 513 *
 514 * In the non-overlapped case you can do a LE lookup and decrement the cursor
 515 * because a record's interval must end before the next record.
 516 */
 517
 518/*
 519 * Return size of the btree block header for this btree instance.
 520 */
 521static inline size_t xfs_btree_block_len(struct xfs_btree_cur *cur)
 522{
 523	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 524		if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
 525			return XFS_BTREE_LBLOCK_CRC_LEN;
 526		return XFS_BTREE_LBLOCK_LEN;
 527	}
 528	if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS)
 529		return XFS_BTREE_SBLOCK_CRC_LEN;
 530	return XFS_BTREE_SBLOCK_LEN;
 531}
 532
 533/*
 534 * Return size of btree block pointers for this btree instance.
 535 */
 536static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
 537{
 538	return (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
 539		sizeof(__be64) : sizeof(__be32);
 540}
 541
 542/*
 543 * Calculate offset of the n-th record in a btree block.
 544 */
 545STATIC size_t
 546xfs_btree_rec_offset(
 547	struct xfs_btree_cur	*cur,
 548	int			n)
 549{
 550	return xfs_btree_block_len(cur) +
 551		(n - 1) * cur->bc_ops->rec_len;
 552}
 553
 554/*
 555 * Calculate offset of the n-th key in a btree block.
 556 */
 557STATIC size_t
 558xfs_btree_key_offset(
 559	struct xfs_btree_cur	*cur,
 560	int			n)
 561{
 562	return xfs_btree_block_len(cur) +
 563		(n - 1) * cur->bc_ops->key_len;
 564}
 565
 566/*
 567 * Calculate offset of the n-th high key in a btree block.
 568 */
 569STATIC size_t
 570xfs_btree_high_key_offset(
 571	struct xfs_btree_cur	*cur,
 572	int			n)
 573{
 574	return xfs_btree_block_len(cur) +
 575		(n - 1) * cur->bc_ops->key_len + (cur->bc_ops->key_len / 2);
 576}
 577
 578/*
 579 * Calculate offset of the n-th block pointer in a btree block.
 580 */
 581STATIC size_t
 582xfs_btree_ptr_offset(
 583	struct xfs_btree_cur	*cur,
 584	int			n,
 585	int			level)
 586{
 587	return xfs_btree_block_len(cur) +
 588		cur->bc_ops->get_maxrecs(cur, level) * cur->bc_ops->key_len +
 589		(n - 1) * xfs_btree_ptr_len(cur);
 590}
 591
 592/*
 593 * Return a pointer to the n-th record in the btree block.
 594 */
 595union xfs_btree_rec *
 596xfs_btree_rec_addr(
 597	struct xfs_btree_cur	*cur,
 598	int			n,
 599	struct xfs_btree_block	*block)
 600{
 601	return (union xfs_btree_rec *)
 602		((char *)block + xfs_btree_rec_offset(cur, n));
 603}
 604
 605/*
 606 * Return a pointer to the n-th key in the btree block.
 607 */
 608union xfs_btree_key *
 609xfs_btree_key_addr(
 610	struct xfs_btree_cur	*cur,
 611	int			n,
 612	struct xfs_btree_block	*block)
 613{
 614	return (union xfs_btree_key *)
 615		((char *)block + xfs_btree_key_offset(cur, n));
 616}
 617
 618/*
 619 * Return a pointer to the n-th high key in the btree block.
 620 */
 621union xfs_btree_key *
 622xfs_btree_high_key_addr(
 623	struct xfs_btree_cur	*cur,
 624	int			n,
 625	struct xfs_btree_block	*block)
 626{
 627	return (union xfs_btree_key *)
 628		((char *)block + xfs_btree_high_key_offset(cur, n));
 629}
 630
 631/*
 632 * Return a pointer to the n-th block pointer in the btree block.
 633 */
 634union xfs_btree_ptr *
 635xfs_btree_ptr_addr(
 636	struct xfs_btree_cur	*cur,
 637	int			n,
 638	struct xfs_btree_block	*block)
 639{
 640	int			level = xfs_btree_get_level(block);
 641
 642	ASSERT(block->bb_level != 0);
 643
 644	return (union xfs_btree_ptr *)
 645		((char *)block + xfs_btree_ptr_offset(cur, n, level));
 646}
 647
 648struct xfs_ifork *
 649xfs_btree_ifork_ptr(
 650	struct xfs_btree_cur	*cur)
 651{
 652	ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
 653
 654	if (cur->bc_flags & XFS_BTREE_STAGING)
 655		return cur->bc_ino.ifake->if_fork;
 656	return XFS_IFORK_PTR(cur->bc_ino.ip, cur->bc_ino.whichfork);
 657}
 658
 659/*
 660 * Get the root block which is stored in the inode.
 661 *
 662 * For now this btree implementation assumes the btree root is always
 663 * stored in the if_broot field of an inode fork.
 664 */
 665STATIC struct xfs_btree_block *
 666xfs_btree_get_iroot(
 667	struct xfs_btree_cur	*cur)
 668{
 669	struct xfs_ifork	*ifp = xfs_btree_ifork_ptr(cur);
 670
 671	return (struct xfs_btree_block *)ifp->if_broot;
 672}
 673
 674/*
 675 * Retrieve the block pointer from the cursor at the given level.
 676 * This may be an inode btree root or from a buffer.
 677 */
 678struct xfs_btree_block *		/* generic btree block pointer */
 679xfs_btree_get_block(
 680	struct xfs_btree_cur	*cur,	/* btree cursor */
 681	int			level,	/* level in btree */
 682	struct xfs_buf		**bpp)	/* buffer containing the block */
 683{
 684	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 685	    (level == cur->bc_nlevels - 1)) {
 686		*bpp = NULL;
 687		return xfs_btree_get_iroot(cur);
 688	}
 689
 690	*bpp = cur->bc_bufs[level];
 691	return XFS_BUF_TO_BLOCK(*bpp);
 692}
 693
 694/*
 695 * Change the cursor to point to the first record at the given level.
 696 * Other levels are unaffected.
 697 */
 698STATIC int				/* success=1, failure=0 */
 699xfs_btree_firstrec(
 700	xfs_btree_cur_t		*cur,	/* btree cursor */
 701	int			level)	/* level to change */
 702{
 703	struct xfs_btree_block	*block;	/* generic btree block pointer */
 704	xfs_buf_t		*bp;	/* buffer containing block */
 705
 706	/*
 707	 * Get the block pointer for this level.
 708	 */
 709	block = xfs_btree_get_block(cur, level, &bp);
 710	if (xfs_btree_check_block(cur, block, level, bp))
 711		return 0;
 712	/*
 713	 * It's empty, there is no such record.
 714	 */
 715	if (!block->bb_numrecs)
 716		return 0;
 717	/*
 718	 * Set the ptr value to 1, that's the first record/key.
 719	 */
 720	cur->bc_ptrs[level] = 1;
 721	return 1;
 722}
 723
 724/*
 725 * Change the cursor to point to the last record in the current block
 726 * at the given level.  Other levels are unaffected.
 727 */
 728STATIC int				/* success=1, failure=0 */
 729xfs_btree_lastrec(
 730	xfs_btree_cur_t		*cur,	/* btree cursor */
 731	int			level)	/* level to change */
 732{
 733	struct xfs_btree_block	*block;	/* generic btree block pointer */
 734	xfs_buf_t		*bp;	/* buffer containing block */
 735
 736	/*
 737	 * Get the block pointer for this level.
 738	 */
 739	block = xfs_btree_get_block(cur, level, &bp);
 740	if (xfs_btree_check_block(cur, block, level, bp))
 741		return 0;
 742	/*
 743	 * It's empty, there is no such record.
 744	 */
 745	if (!block->bb_numrecs)
 746		return 0;
 747	/*
 748	 * Set the ptr value to numrecs, that's the last record/key.
 749	 */
 750	cur->bc_ptrs[level] = be16_to_cpu(block->bb_numrecs);
 751	return 1;
 752}
 753
 754/*
 755 * Compute first and last byte offsets for the fields given.
 756 * Interprets the offsets table, which contains struct field offsets.
 757 */
 758void
 759xfs_btree_offsets(
 760	int64_t		fields,		/* bitmask of fields */
 761	const short	*offsets,	/* table of field offsets */
 762	int		nbits,		/* number of bits to inspect */
 763	int		*first,		/* output: first byte offset */
 764	int		*last)		/* output: last byte offset */
 765{
 766	int		i;		/* current bit number */
 767	int64_t		imask;		/* mask for current bit number */
 768
 769	ASSERT(fields != 0);
 770	/*
 771	 * Find the lowest bit, so the first byte offset.
 772	 */
 773	for (i = 0, imask = 1LL; ; i++, imask <<= 1) {
 774		if (imask & fields) {
 775			*first = offsets[i];
 776			break;
 777		}
 778	}
 779	/*
 780	 * Find the highest bit, so the last byte offset.
 781	 */
 782	for (i = nbits - 1, imask = 1LL << i; ; i--, imask >>= 1) {
 783		if (imask & fields) {
 784			*last = offsets[i + 1] - 1;
 785			break;
 786		}
 787	}
 788}
 789
 790/*
 791 * Get a buffer for the block, return it read in.
 792 * Long-form addressing.
 793 */
 794int
 795xfs_btree_read_bufl(
 796	struct xfs_mount	*mp,		/* file system mount point */
 797	struct xfs_trans	*tp,		/* transaction pointer */
 798	xfs_fsblock_t		fsbno,		/* file system block number */
 799	struct xfs_buf		**bpp,		/* buffer for fsbno */
 800	int			refval,		/* ref count value for buffer */
 801	const struct xfs_buf_ops *ops)
 802{
 803	struct xfs_buf		*bp;		/* return value */
 804	xfs_daddr_t		d;		/* real disk block address */
 805	int			error;
 806
 807	if (!xfs_verify_fsbno(mp, fsbno))
 808		return -EFSCORRUPTED;
 809	d = XFS_FSB_TO_DADDR(mp, fsbno);
 810	error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp, d,
 811				   mp->m_bsize, 0, &bp, ops);
 812	if (error)
 813		return error;
 814	if (bp)
 815		xfs_buf_set_ref(bp, refval);
 816	*bpp = bp;
 817	return 0;
 818}
 819
 820/*
 821 * Read-ahead the block, don't wait for it, don't return a buffer.
 822 * Long-form addressing.
 823 */
 824/* ARGSUSED */
 825void
 826xfs_btree_reada_bufl(
 827	struct xfs_mount	*mp,		/* file system mount point */
 828	xfs_fsblock_t		fsbno,		/* file system block number */
 829	xfs_extlen_t		count,		/* count of filesystem blocks */
 830	const struct xfs_buf_ops *ops)
 831{
 832	xfs_daddr_t		d;
 833
 834	ASSERT(fsbno != NULLFSBLOCK);
 835	d = XFS_FSB_TO_DADDR(mp, fsbno);
 836	xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
 837}
 838
 839/*
 840 * Read-ahead the block, don't wait for it, don't return a buffer.
 841 * Short-form addressing.
 842 */
 843/* ARGSUSED */
 844void
 845xfs_btree_reada_bufs(
 846	struct xfs_mount	*mp,		/* file system mount point */
 847	xfs_agnumber_t		agno,		/* allocation group number */
 848	xfs_agblock_t		agbno,		/* allocation group block number */
 849	xfs_extlen_t		count,		/* count of filesystem blocks */
 850	const struct xfs_buf_ops *ops)
 851{
 852	xfs_daddr_t		d;
 853
 854	ASSERT(agno != NULLAGNUMBER);
 855	ASSERT(agbno != NULLAGBLOCK);
 856	d = XFS_AGB_TO_DADDR(mp, agno, agbno);
 857	xfs_buf_readahead(mp->m_ddev_targp, d, mp->m_bsize * count, ops);
 858}
 859
 860STATIC int
 861xfs_btree_readahead_lblock(
 862	struct xfs_btree_cur	*cur,
 863	int			lr,
 864	struct xfs_btree_block	*block)
 865{
 866	int			rval = 0;
 867	xfs_fsblock_t		left = be64_to_cpu(block->bb_u.l.bb_leftsib);
 868	xfs_fsblock_t		right = be64_to_cpu(block->bb_u.l.bb_rightsib);
 869
 870	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLFSBLOCK) {
 871		xfs_btree_reada_bufl(cur->bc_mp, left, 1,
 872				     cur->bc_ops->buf_ops);
 873		rval++;
 874	}
 875
 876	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLFSBLOCK) {
 877		xfs_btree_reada_bufl(cur->bc_mp, right, 1,
 878				     cur->bc_ops->buf_ops);
 879		rval++;
 880	}
 881
 882	return rval;
 883}
 884
 885STATIC int
 886xfs_btree_readahead_sblock(
 887	struct xfs_btree_cur	*cur,
 888	int			lr,
 889	struct xfs_btree_block *block)
 890{
 891	int			rval = 0;
 892	xfs_agblock_t		left = be32_to_cpu(block->bb_u.s.bb_leftsib);
 893	xfs_agblock_t		right = be32_to_cpu(block->bb_u.s.bb_rightsib);
 894
 895
 896	if ((lr & XFS_BTCUR_LEFTRA) && left != NULLAGBLOCK) {
 897		xfs_btree_reada_bufs(cur->bc_mp, cur->bc_ag.agno,
 898				     left, 1, cur->bc_ops->buf_ops);
 899		rval++;
 900	}
 901
 902	if ((lr & XFS_BTCUR_RIGHTRA) && right != NULLAGBLOCK) {
 903		xfs_btree_reada_bufs(cur->bc_mp, cur->bc_ag.agno,
 904				     right, 1, cur->bc_ops->buf_ops);
 905		rval++;
 906	}
 907
 908	return rval;
 909}
 910
 911/*
 912 * Read-ahead btree blocks, at the given level.
 913 * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
 914 */
 915STATIC int
 916xfs_btree_readahead(
 917	struct xfs_btree_cur	*cur,		/* btree cursor */
 918	int			lev,		/* level in btree */
 919	int			lr)		/* left/right bits */
 920{
 921	struct xfs_btree_block	*block;
 922
 923	/*
 924	 * No readahead needed if we are at the root level and the
 925	 * btree root is stored in the inode.
 926	 */
 927	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
 928	    (lev == cur->bc_nlevels - 1))
 929		return 0;
 930
 931	if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
 932		return 0;
 933
 934	cur->bc_ra[lev] |= lr;
 935	block = XFS_BUF_TO_BLOCK(cur->bc_bufs[lev]);
 936
 937	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
 938		return xfs_btree_readahead_lblock(cur, lr, block);
 939	return xfs_btree_readahead_sblock(cur, lr, block);
 940}
 941
 942STATIC int
 943xfs_btree_ptr_to_daddr(
 944	struct xfs_btree_cur	*cur,
 945	union xfs_btree_ptr	*ptr,
 946	xfs_daddr_t		*daddr)
 947{
 948	xfs_fsblock_t		fsbno;
 949	xfs_agblock_t		agbno;
 950	int			error;
 951
 952	error = xfs_btree_check_ptr(cur, ptr, 0, 1);
 953	if (error)
 954		return error;
 955
 956	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
 957		fsbno = be64_to_cpu(ptr->l);
 958		*daddr = XFS_FSB_TO_DADDR(cur->bc_mp, fsbno);
 959	} else {
 960		agbno = be32_to_cpu(ptr->s);
 961		*daddr = XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_ag.agno,
 962				agbno);
 963	}
 964
 965	return 0;
 966}
 967
 968/*
 969 * Readahead @count btree blocks at the given @ptr location.
 970 *
 971 * We don't need to care about long or short form btrees here as we have a
 972 * method of converting the ptr directly to a daddr available to us.
 973 */
 974STATIC void
 975xfs_btree_readahead_ptr(
 976	struct xfs_btree_cur	*cur,
 977	union xfs_btree_ptr	*ptr,
 978	xfs_extlen_t		count)
 979{
 980	xfs_daddr_t		daddr;
 981
 982	if (xfs_btree_ptr_to_daddr(cur, ptr, &daddr))
 983		return;
 984	xfs_buf_readahead(cur->bc_mp->m_ddev_targp, daddr,
 985			  cur->bc_mp->m_bsize * count, cur->bc_ops->buf_ops);
 986}
 987
 988/*
 989 * Set the buffer for level "lev" in the cursor to bp, releasing
 990 * any previous buffer.
 991 */
 992STATIC void
 993xfs_btree_setbuf(
 994	xfs_btree_cur_t		*cur,	/* btree cursor */
 995	int			lev,	/* level in btree */
 996	xfs_buf_t		*bp)	/* new buffer to set */
 997{
 998	struct xfs_btree_block	*b;	/* btree block */
 999
1000	if (cur->bc_bufs[lev])
1001		xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[lev]);
1002	cur->bc_bufs[lev] = bp;
1003	cur->bc_ra[lev] = 0;
1004
1005	b = XFS_BUF_TO_BLOCK(bp);
1006	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1007		if (b->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK))
1008			cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
1009		if (b->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK))
1010			cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
1011	} else {
1012		if (b->bb_u.s.bb_leftsib == cpu_to_be32(NULLAGBLOCK))
1013			cur->bc_ra[lev] |= XFS_BTCUR_LEFTRA;
1014		if (b->bb_u.s.bb_rightsib == cpu_to_be32(NULLAGBLOCK))
1015			cur->bc_ra[lev] |= XFS_BTCUR_RIGHTRA;
1016	}
1017}
1018
1019bool
1020xfs_btree_ptr_is_null(
1021	struct xfs_btree_cur	*cur,
1022	union xfs_btree_ptr	*ptr)
1023{
1024	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1025		return ptr->l == cpu_to_be64(NULLFSBLOCK);
1026	else
1027		return ptr->s == cpu_to_be32(NULLAGBLOCK);
1028}
1029
1030void
1031xfs_btree_set_ptr_null(
1032	struct xfs_btree_cur	*cur,
1033	union xfs_btree_ptr	*ptr)
1034{
1035	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1036		ptr->l = cpu_to_be64(NULLFSBLOCK);
1037	else
1038		ptr->s = cpu_to_be32(NULLAGBLOCK);
1039}
1040
1041/*
1042 * Get/set/init sibling pointers
1043 */
1044void
1045xfs_btree_get_sibling(
1046	struct xfs_btree_cur	*cur,
1047	struct xfs_btree_block	*block,
1048	union xfs_btree_ptr	*ptr,
1049	int			lr)
1050{
1051	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1052
1053	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1054		if (lr == XFS_BB_RIGHTSIB)
1055			ptr->l = block->bb_u.l.bb_rightsib;
1056		else
1057			ptr->l = block->bb_u.l.bb_leftsib;
1058	} else {
1059		if (lr == XFS_BB_RIGHTSIB)
1060			ptr->s = block->bb_u.s.bb_rightsib;
1061		else
1062			ptr->s = block->bb_u.s.bb_leftsib;
1063	}
1064}
1065
1066void
1067xfs_btree_set_sibling(
1068	struct xfs_btree_cur	*cur,
1069	struct xfs_btree_block	*block,
1070	union xfs_btree_ptr	*ptr,
1071	int			lr)
1072{
1073	ASSERT(lr == XFS_BB_LEFTSIB || lr == XFS_BB_RIGHTSIB);
1074
1075	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
1076		if (lr == XFS_BB_RIGHTSIB)
1077			block->bb_u.l.bb_rightsib = ptr->l;
1078		else
1079			block->bb_u.l.bb_leftsib = ptr->l;
1080	} else {
1081		if (lr == XFS_BB_RIGHTSIB)
1082			block->bb_u.s.bb_rightsib = ptr->s;
1083		else
1084			block->bb_u.s.bb_leftsib = ptr->s;
1085	}
1086}
1087
1088void
1089xfs_btree_init_block_int(
1090	struct xfs_mount	*mp,
1091	struct xfs_btree_block	*buf,
1092	xfs_daddr_t		blkno,
1093	xfs_btnum_t		btnum,
1094	__u16			level,
1095	__u16			numrecs,
1096	__u64			owner,
1097	unsigned int		flags)
1098{
1099	int			crc = xfs_sb_version_hascrc(&mp->m_sb);
1100	__u32			magic = xfs_btree_magic(crc, btnum);
1101
1102	buf->bb_magic = cpu_to_be32(magic);
1103	buf->bb_level = cpu_to_be16(level);
1104	buf->bb_numrecs = cpu_to_be16(numrecs);
1105
1106	if (flags & XFS_BTREE_LONG_PTRS) {
1107		buf->bb_u.l.bb_leftsib = cpu_to_be64(NULLFSBLOCK);
1108		buf->bb_u.l.bb_rightsib = cpu_to_be64(NULLFSBLOCK);
1109		if (crc) {
1110			buf->bb_u.l.bb_blkno = cpu_to_be64(blkno);
1111			buf->bb_u.l.bb_owner = cpu_to_be64(owner);
1112			uuid_copy(&buf->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid);
1113			buf->bb_u.l.bb_pad = 0;
1114			buf->bb_u.l.bb_lsn = 0;
1115		}
1116	} else {
1117		/* owner is a 32 bit value on short blocks */
1118		__u32 __owner = (__u32)owner;
1119
1120		buf->bb_u.s.bb_leftsib = cpu_to_be32(NULLAGBLOCK);
1121		buf->bb_u.s.bb_rightsib = cpu_to_be32(NULLAGBLOCK);
1122		if (crc) {
1123			buf->bb_u.s.bb_blkno = cpu_to_be64(blkno);
1124			buf->bb_u.s.bb_owner = cpu_to_be32(__owner);
1125			uuid_copy(&buf->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid);
1126			buf->bb_u.s.bb_lsn = 0;
1127		}
1128	}
1129}
1130
1131void
1132xfs_btree_init_block(
1133	struct xfs_mount *mp,
1134	struct xfs_buf	*bp,
1135	xfs_btnum_t	btnum,
1136	__u16		level,
1137	__u16		numrecs,
1138	__u64		owner)
1139{
1140	xfs_btree_init_block_int(mp, XFS_BUF_TO_BLOCK(bp), bp->b_bn,
1141				 btnum, level, numrecs, owner, 0);
1142}
1143
1144void
1145xfs_btree_init_block_cur(
1146	struct xfs_btree_cur	*cur,
1147	struct xfs_buf		*bp,
1148	int			level,
1149	int			numrecs)
1150{
1151	__u64			owner;
1152
1153	/*
1154	 * we can pull the owner from the cursor right now as the different
1155	 * owners align directly with the pointer size of the btree. This may
1156	 * change in future, but is safe for current users of the generic btree
1157	 * code.
1158	 */
1159	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1160		owner = cur->bc_ino.ip->i_ino;
1161	else
1162		owner = cur->bc_ag.agno;
1163
1164	xfs_btree_init_block_int(cur->bc_mp, XFS_BUF_TO_BLOCK(bp), bp->b_bn,
1165				 cur->bc_btnum, level, numrecs,
1166				 owner, cur->bc_flags);
1167}
1168
1169/*
1170 * Return true if ptr is the last record in the btree and
1171 * we need to track updates to this record.  The decision
1172 * will be further refined in the update_lastrec method.
1173 */
1174STATIC int
1175xfs_btree_is_lastrec(
1176	struct xfs_btree_cur	*cur,
1177	struct xfs_btree_block	*block,
1178	int			level)
1179{
1180	union xfs_btree_ptr	ptr;
1181
1182	if (level > 0)
1183		return 0;
1184	if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
1185		return 0;
1186
1187	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1188	if (!xfs_btree_ptr_is_null(cur, &ptr))
1189		return 0;
1190	return 1;
1191}
1192
1193STATIC void
1194xfs_btree_buf_to_ptr(
1195	struct xfs_btree_cur	*cur,
1196	struct xfs_buf		*bp,
1197	union xfs_btree_ptr	*ptr)
1198{
1199	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
1200		ptr->l = cpu_to_be64(XFS_DADDR_TO_FSB(cur->bc_mp,
1201					XFS_BUF_ADDR(bp)));
1202	else {
1203		ptr->s = cpu_to_be32(xfs_daddr_to_agbno(cur->bc_mp,
1204					XFS_BUF_ADDR(bp)));
1205	}
1206}
1207
1208STATIC void
1209xfs_btree_set_refs(
1210	struct xfs_btree_cur	*cur,
1211	struct xfs_buf		*bp)
1212{
1213	switch (cur->bc_btnum) {
1214	case XFS_BTNUM_BNO:
1215	case XFS_BTNUM_CNT:
1216		xfs_buf_set_ref(bp, XFS_ALLOC_BTREE_REF);
1217		break;
1218	case XFS_BTNUM_INO:
1219	case XFS_BTNUM_FINO:
1220		xfs_buf_set_ref(bp, XFS_INO_BTREE_REF);
1221		break;
1222	case XFS_BTNUM_BMAP:
1223		xfs_buf_set_ref(bp, XFS_BMAP_BTREE_REF);
1224		break;
1225	case XFS_BTNUM_RMAP:
1226		xfs_buf_set_ref(bp, XFS_RMAP_BTREE_REF);
1227		break;
1228	case XFS_BTNUM_REFC:
1229		xfs_buf_set_ref(bp, XFS_REFC_BTREE_REF);
1230		break;
1231	default:
1232		ASSERT(0);
1233	}
1234}
1235
1236int
1237xfs_btree_get_buf_block(
1238	struct xfs_btree_cur	*cur,
1239	union xfs_btree_ptr	*ptr,
1240	struct xfs_btree_block	**block,
1241	struct xfs_buf		**bpp)
1242{
1243	struct xfs_mount	*mp = cur->bc_mp;
1244	xfs_daddr_t		d;
1245	int			error;
1246
1247	error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1248	if (error)
1249		return error;
1250	error = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d, mp->m_bsize,
1251			0, bpp);
1252	if (error)
1253		return error;
1254
1255	(*bpp)->b_ops = cur->bc_ops->buf_ops;
1256	*block = XFS_BUF_TO_BLOCK(*bpp);
1257	return 0;
1258}
1259
1260/*
1261 * Read in the buffer at the given ptr and return the buffer and
1262 * the block pointer within the buffer.
1263 */
1264STATIC int
1265xfs_btree_read_buf_block(
1266	struct xfs_btree_cur	*cur,
1267	union xfs_btree_ptr	*ptr,
1268	int			flags,
1269	struct xfs_btree_block	**block,
1270	struct xfs_buf		**bpp)
1271{
1272	struct xfs_mount	*mp = cur->bc_mp;
1273	xfs_daddr_t		d;
1274	int			error;
1275
1276	/* need to sort out how callers deal with failures first */
1277	ASSERT(!(flags & XBF_TRYLOCK));
1278
1279	error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
1280	if (error)
1281		return error;
1282	error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
1283				   mp->m_bsize, flags, bpp,
1284				   cur->bc_ops->buf_ops);
1285	if (error)
1286		return error;
1287
1288	xfs_btree_set_refs(cur, *bpp);
1289	*block = XFS_BUF_TO_BLOCK(*bpp);
1290	return 0;
1291}
1292
1293/*
1294 * Copy keys from one btree block to another.
1295 */
1296void
1297xfs_btree_copy_keys(
1298	struct xfs_btree_cur	*cur,
1299	union xfs_btree_key	*dst_key,
1300	union xfs_btree_key	*src_key,
1301	int			numkeys)
1302{
1303	ASSERT(numkeys >= 0);
1304	memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
1305}
1306
1307/*
1308 * Copy records from one btree block to another.
1309 */
1310STATIC void
1311xfs_btree_copy_recs(
1312	struct xfs_btree_cur	*cur,
1313	union xfs_btree_rec	*dst_rec,
1314	union xfs_btree_rec	*src_rec,
1315	int			numrecs)
1316{
1317	ASSERT(numrecs >= 0);
1318	memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
1319}
1320
1321/*
1322 * Copy block pointers from one btree block to another.
1323 */
1324void
1325xfs_btree_copy_ptrs(
1326	struct xfs_btree_cur	*cur,
1327	union xfs_btree_ptr	*dst_ptr,
1328	const union xfs_btree_ptr *src_ptr,
1329	int			numptrs)
1330{
1331	ASSERT(numptrs >= 0);
1332	memcpy(dst_ptr, src_ptr, numptrs * xfs_btree_ptr_len(cur));
1333}
1334
1335/*
1336 * Shift keys one index left/right inside a single btree block.
1337 */
1338STATIC void
1339xfs_btree_shift_keys(
1340	struct xfs_btree_cur	*cur,
1341	union xfs_btree_key	*key,
1342	int			dir,
1343	int			numkeys)
1344{
1345	char			*dst_key;
1346
1347	ASSERT(numkeys >= 0);
1348	ASSERT(dir == 1 || dir == -1);
1349
1350	dst_key = (char *)key + (dir * cur->bc_ops->key_len);
1351	memmove(dst_key, key, numkeys * cur->bc_ops->key_len);
1352}
1353
1354/*
1355 * Shift records one index left/right inside a single btree block.
1356 */
1357STATIC void
1358xfs_btree_shift_recs(
1359	struct xfs_btree_cur	*cur,
1360	union xfs_btree_rec	*rec,
1361	int			dir,
1362	int			numrecs)
1363{
1364	char			*dst_rec;
1365
1366	ASSERT(numrecs >= 0);
1367	ASSERT(dir == 1 || dir == -1);
1368
1369	dst_rec = (char *)rec + (dir * cur->bc_ops->rec_len);
1370	memmove(dst_rec, rec, numrecs * cur->bc_ops->rec_len);
1371}
1372
1373/*
1374 * Shift block pointers one index left/right inside a single btree block.
1375 */
1376STATIC void
1377xfs_btree_shift_ptrs(
1378	struct xfs_btree_cur	*cur,
1379	union xfs_btree_ptr	*ptr,
1380	int			dir,
1381	int			numptrs)
1382{
1383	char			*dst_ptr;
1384
1385	ASSERT(numptrs >= 0);
1386	ASSERT(dir == 1 || dir == -1);
1387
1388	dst_ptr = (char *)ptr + (dir * xfs_btree_ptr_len(cur));
1389	memmove(dst_ptr, ptr, numptrs * xfs_btree_ptr_len(cur));
1390}
1391
1392/*
1393 * Log key values from the btree block.
1394 */
1395STATIC void
1396xfs_btree_log_keys(
1397	struct xfs_btree_cur	*cur,
1398	struct xfs_buf		*bp,
1399	int			first,
1400	int			last)
1401{
1402
1403	if (bp) {
1404		xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1405		xfs_trans_log_buf(cur->bc_tp, bp,
1406				  xfs_btree_key_offset(cur, first),
1407				  xfs_btree_key_offset(cur, last + 1) - 1);
1408	} else {
1409		xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1410				xfs_ilog_fbroot(cur->bc_ino.whichfork));
1411	}
1412}
1413
1414/*
1415 * Log record values from the btree block.
1416 */
1417void
1418xfs_btree_log_recs(
1419	struct xfs_btree_cur	*cur,
1420	struct xfs_buf		*bp,
1421	int			first,
1422	int			last)
1423{
1424
1425	xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1426	xfs_trans_log_buf(cur->bc_tp, bp,
1427			  xfs_btree_rec_offset(cur, first),
1428			  xfs_btree_rec_offset(cur, last + 1) - 1);
1429
1430}
1431
1432/*
1433 * Log block pointer fields from a btree block (nonleaf).
1434 */
1435STATIC void
1436xfs_btree_log_ptrs(
1437	struct xfs_btree_cur	*cur,	/* btree cursor */
1438	struct xfs_buf		*bp,	/* buffer containing btree block */
1439	int			first,	/* index of first pointer to log */
1440	int			last)	/* index of last pointer to log */
1441{
1442
1443	if (bp) {
1444		struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
1445		int			level = xfs_btree_get_level(block);
1446
1447		xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1448		xfs_trans_log_buf(cur->bc_tp, bp,
1449				xfs_btree_ptr_offset(cur, first, level),
1450				xfs_btree_ptr_offset(cur, last + 1, level) - 1);
1451	} else {
1452		xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1453			xfs_ilog_fbroot(cur->bc_ino.whichfork));
1454	}
1455
1456}
1457
1458/*
1459 * Log fields from a btree block header.
1460 */
1461void
1462xfs_btree_log_block(
1463	struct xfs_btree_cur	*cur,	/* btree cursor */
1464	struct xfs_buf		*bp,	/* buffer containing btree block */
1465	int			fields)	/* mask of fields: XFS_BB_... */
1466{
1467	int			first;	/* first byte offset logged */
1468	int			last;	/* last byte offset logged */
1469	static const short	soffsets[] = {	/* table of offsets (short) */
1470		offsetof(struct xfs_btree_block, bb_magic),
1471		offsetof(struct xfs_btree_block, bb_level),
1472		offsetof(struct xfs_btree_block, bb_numrecs),
1473		offsetof(struct xfs_btree_block, bb_u.s.bb_leftsib),
1474		offsetof(struct xfs_btree_block, bb_u.s.bb_rightsib),
1475		offsetof(struct xfs_btree_block, bb_u.s.bb_blkno),
1476		offsetof(struct xfs_btree_block, bb_u.s.bb_lsn),
1477		offsetof(struct xfs_btree_block, bb_u.s.bb_uuid),
1478		offsetof(struct xfs_btree_block, bb_u.s.bb_owner),
1479		offsetof(struct xfs_btree_block, bb_u.s.bb_crc),
1480		XFS_BTREE_SBLOCK_CRC_LEN
1481	};
1482	static const short	loffsets[] = {	/* table of offsets (long) */
1483		offsetof(struct xfs_btree_block, bb_magic),
1484		offsetof(struct xfs_btree_block, bb_level),
1485		offsetof(struct xfs_btree_block, bb_numrecs),
1486		offsetof(struct xfs_btree_block, bb_u.l.bb_leftsib),
1487		offsetof(struct xfs_btree_block, bb_u.l.bb_rightsib),
1488		offsetof(struct xfs_btree_block, bb_u.l.bb_blkno),
1489		offsetof(struct xfs_btree_block, bb_u.l.bb_lsn),
1490		offsetof(struct xfs_btree_block, bb_u.l.bb_uuid),
1491		offsetof(struct xfs_btree_block, bb_u.l.bb_owner),
1492		offsetof(struct xfs_btree_block, bb_u.l.bb_crc),
1493		offsetof(struct xfs_btree_block, bb_u.l.bb_pad),
1494		XFS_BTREE_LBLOCK_CRC_LEN
1495	};
1496
1497	if (bp) {
1498		int nbits;
1499
1500		if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
1501			/*
1502			 * We don't log the CRC when updating a btree
1503			 * block but instead recreate it during log
1504			 * recovery.  As the log buffers have checksums
1505			 * of their own this is safe and avoids logging a crc
1506			 * update in a lot of places.
1507			 */
1508			if (fields == XFS_BB_ALL_BITS)
1509				fields = XFS_BB_ALL_BITS_CRC;
1510			nbits = XFS_BB_NUM_BITS_CRC;
1511		} else {
1512			nbits = XFS_BB_NUM_BITS;
1513		}
1514		xfs_btree_offsets(fields,
1515				  (cur->bc_flags & XFS_BTREE_LONG_PTRS) ?
1516					loffsets : soffsets,
1517				  nbits, &first, &last);
1518		xfs_trans_buf_set_type(cur->bc_tp, bp, XFS_BLFT_BTREE_BUF);
1519		xfs_trans_log_buf(cur->bc_tp, bp, first, last);
1520	} else {
1521		xfs_trans_log_inode(cur->bc_tp, cur->bc_ino.ip,
1522			xfs_ilog_fbroot(cur->bc_ino.whichfork));
1523	}
1524}
1525
1526/*
1527 * Increment cursor by one record at the level.
1528 * For nonzero levels the leaf-ward information is untouched.
1529 */
1530int						/* error */
1531xfs_btree_increment(
1532	struct xfs_btree_cur	*cur,
1533	int			level,
1534	int			*stat)		/* success/failure */
1535{
1536	struct xfs_btree_block	*block;
1537	union xfs_btree_ptr	ptr;
1538	struct xfs_buf		*bp;
1539	int			error;		/* error return value */
1540	int			lev;
1541
1542	ASSERT(level < cur->bc_nlevels);
1543
1544	/* Read-ahead to the right at this level. */
1545	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
1546
1547	/* Get a pointer to the btree block. */
1548	block = xfs_btree_get_block(cur, level, &bp);
1549
1550#ifdef DEBUG
1551	error = xfs_btree_check_block(cur, block, level, bp);
1552	if (error)
1553		goto error0;
1554#endif
1555
1556	/* We're done if we remain in the block after the increment. */
1557	if (++cur->bc_ptrs[level] <= xfs_btree_get_numrecs(block))
1558		goto out1;
1559
1560	/* Fail if we just went off the right edge of the tree. */
1561	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1562	if (xfs_btree_ptr_is_null(cur, &ptr))
1563		goto out0;
1564
1565	XFS_BTREE_STATS_INC(cur, increment);
1566
1567	/*
1568	 * March up the tree incrementing pointers.
1569	 * Stop when we don't go off the right edge of a block.
1570	 */
1571	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1572		block = xfs_btree_get_block(cur, lev, &bp);
1573
1574#ifdef DEBUG
1575		error = xfs_btree_check_block(cur, block, lev, bp);
1576		if (error)
1577			goto error0;
1578#endif
1579
1580		if (++cur->bc_ptrs[lev] <= xfs_btree_get_numrecs(block))
1581			break;
1582
1583		/* Read-ahead the right block for the next loop. */
1584		xfs_btree_readahead(cur, lev, XFS_BTCUR_RIGHTRA);
1585	}
1586
1587	/*
1588	 * If we went off the root then we are either seriously
1589	 * confused or have the tree root in an inode.
1590	 */
1591	if (lev == cur->bc_nlevels) {
1592		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1593			goto out0;
1594		ASSERT(0);
1595		error = -EFSCORRUPTED;
1596		goto error0;
1597	}
1598	ASSERT(lev < cur->bc_nlevels);
1599
1600	/*
1601	 * Now walk back down the tree, fixing up the cursor's buffer
1602	 * pointers and key numbers.
1603	 */
1604	for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1605		union xfs_btree_ptr	*ptrp;
1606
1607		ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1608		--lev;
1609		error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1610		if (error)
1611			goto error0;
1612
1613		xfs_btree_setbuf(cur, lev, bp);
1614		cur->bc_ptrs[lev] = 1;
1615	}
1616out1:
1617	*stat = 1;
1618	return 0;
1619
1620out0:
1621	*stat = 0;
1622	return 0;
1623
1624error0:
1625	return error;
1626}
1627
1628/*
1629 * Decrement cursor by one record at the level.
1630 * For nonzero levels the leaf-ward information is untouched.
1631 */
1632int						/* error */
1633xfs_btree_decrement(
1634	struct xfs_btree_cur	*cur,
1635	int			level,
1636	int			*stat)		/* success/failure */
1637{
1638	struct xfs_btree_block	*block;
1639	xfs_buf_t		*bp;
1640	int			error;		/* error return value */
1641	int			lev;
1642	union xfs_btree_ptr	ptr;
1643
1644	ASSERT(level < cur->bc_nlevels);
1645
1646	/* Read-ahead to the left at this level. */
1647	xfs_btree_readahead(cur, level, XFS_BTCUR_LEFTRA);
1648
1649	/* We're done if we remain in the block after the decrement. */
1650	if (--cur->bc_ptrs[level] > 0)
1651		goto out1;
1652
1653	/* Get a pointer to the btree block. */
1654	block = xfs_btree_get_block(cur, level, &bp);
1655
1656#ifdef DEBUG
1657	error = xfs_btree_check_block(cur, block, level, bp);
1658	if (error)
1659		goto error0;
1660#endif
1661
1662	/* Fail if we just went off the left edge of the tree. */
1663	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
1664	if (xfs_btree_ptr_is_null(cur, &ptr))
1665		goto out0;
1666
1667	XFS_BTREE_STATS_INC(cur, decrement);
1668
1669	/*
1670	 * March up the tree decrementing pointers.
1671	 * Stop when we don't go off the left edge of a block.
1672	 */
1673	for (lev = level + 1; lev < cur->bc_nlevels; lev++) {
1674		if (--cur->bc_ptrs[lev] > 0)
1675			break;
1676		/* Read-ahead the left block for the next loop. */
1677		xfs_btree_readahead(cur, lev, XFS_BTCUR_LEFTRA);
1678	}
1679
1680	/*
1681	 * If we went off the root then we are seriously confused.
1682	 * or the root of the tree is in an inode.
1683	 */
1684	if (lev == cur->bc_nlevels) {
1685		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE)
1686			goto out0;
1687		ASSERT(0);
1688		error = -EFSCORRUPTED;
1689		goto error0;
1690	}
1691	ASSERT(lev < cur->bc_nlevels);
1692
1693	/*
1694	 * Now walk back down the tree, fixing up the cursor's buffer
1695	 * pointers and key numbers.
1696	 */
1697	for (block = xfs_btree_get_block(cur, lev, &bp); lev > level; ) {
1698		union xfs_btree_ptr	*ptrp;
1699
1700		ptrp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[lev], block);
1701		--lev;
1702		error = xfs_btree_read_buf_block(cur, ptrp, 0, &block, &bp);
1703		if (error)
1704			goto error0;
1705		xfs_btree_setbuf(cur, lev, bp);
1706		cur->bc_ptrs[lev] = xfs_btree_get_numrecs(block);
1707	}
1708out1:
1709	*stat = 1;
1710	return 0;
1711
1712out0:
1713	*stat = 0;
1714	return 0;
1715
1716error0:
1717	return error;
1718}
1719
1720int
1721xfs_btree_lookup_get_block(
1722	struct xfs_btree_cur	*cur,	/* btree cursor */
1723	int			level,	/* level in the btree */
1724	union xfs_btree_ptr	*pp,	/* ptr to btree block */
1725	struct xfs_btree_block	**blkp) /* return btree block */
1726{
1727	struct xfs_buf		*bp;	/* buffer pointer for btree block */
1728	xfs_daddr_t		daddr;
1729	int			error = 0;
1730
1731	/* special case the root block if in an inode */
1732	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
1733	    (level == cur->bc_nlevels - 1)) {
1734		*blkp = xfs_btree_get_iroot(cur);
1735		return 0;
1736	}
1737
1738	/*
1739	 * If the old buffer at this level for the disk address we are
1740	 * looking for re-use it.
1741	 *
1742	 * Otherwise throw it away and get a new one.
1743	 */
1744	bp = cur->bc_bufs[level];
1745	error = xfs_btree_ptr_to_daddr(cur, pp, &daddr);
1746	if (error)
1747		return error;
1748	if (bp && XFS_BUF_ADDR(bp) == daddr) {
1749		*blkp = XFS_BUF_TO_BLOCK(bp);
1750		return 0;
1751	}
1752
1753	error = xfs_btree_read_buf_block(cur, pp, 0, blkp, &bp);
1754	if (error)
1755		return error;
1756
1757	/* Check the inode owner since the verifiers don't. */
1758	if (xfs_sb_version_hascrc(&cur->bc_mp->m_sb) &&
1759	    !(cur->bc_ino.flags & XFS_BTCUR_BMBT_INVALID_OWNER) &&
1760	    (cur->bc_flags & XFS_BTREE_LONG_PTRS) &&
1761	    be64_to_cpu((*blkp)->bb_u.l.bb_owner) !=
1762			cur->bc_ino.ip->i_ino)
1763		goto out_bad;
1764
1765	/* Did we get the level we were looking for? */
1766	if (be16_to_cpu((*blkp)->bb_level) != level)
1767		goto out_bad;
1768
1769	/* Check that internal nodes have at least one record. */
1770	if (level != 0 && be16_to_cpu((*blkp)->bb_numrecs) == 0)
1771		goto out_bad;
1772
1773	xfs_btree_setbuf(cur, level, bp);
1774	return 0;
1775
1776out_bad:
1777	*blkp = NULL;
1778	xfs_buf_mark_corrupt(bp);
1779	xfs_trans_brelse(cur->bc_tp, bp);
1780	return -EFSCORRUPTED;
1781}
1782
1783/*
1784 * Get current search key.  For level 0 we don't actually have a key
1785 * structure so we make one up from the record.  For all other levels
1786 * we just return the right key.
1787 */
1788STATIC union xfs_btree_key *
1789xfs_lookup_get_search_key(
1790	struct xfs_btree_cur	*cur,
1791	int			level,
1792	int			keyno,
1793	struct xfs_btree_block	*block,
1794	union xfs_btree_key	*kp)
1795{
1796	if (level == 0) {
1797		cur->bc_ops->init_key_from_rec(kp,
1798				xfs_btree_rec_addr(cur, keyno, block));
1799		return kp;
1800	}
1801
1802	return xfs_btree_key_addr(cur, keyno, block);
1803}
1804
1805/*
1806 * Lookup the record.  The cursor is made to point to it, based on dir.
1807 * stat is set to 0 if can't find any such record, 1 for success.
1808 */
1809int					/* error */
1810xfs_btree_lookup(
1811	struct xfs_btree_cur	*cur,	/* btree cursor */
1812	xfs_lookup_t		dir,	/* <=, ==, or >= */
1813	int			*stat)	/* success/failure */
1814{
1815	struct xfs_btree_block	*block;	/* current btree block */
1816	int64_t			diff;	/* difference for the current key */
1817	int			error;	/* error return value */
1818	int			keyno;	/* current key number */
1819	int			level;	/* level in the btree */
1820	union xfs_btree_ptr	*pp;	/* ptr to btree block */
1821	union xfs_btree_ptr	ptr;	/* ptr to btree block */
1822
1823	XFS_BTREE_STATS_INC(cur, lookup);
1824
1825	/* No such thing as a zero-level tree. */
1826	if (XFS_IS_CORRUPT(cur->bc_mp, cur->bc_nlevels == 0))
1827		return -EFSCORRUPTED;
1828
1829	block = NULL;
1830	keyno = 0;
1831
1832	/* initialise start pointer from cursor */
1833	cur->bc_ops->init_ptr_from_cur(cur, &ptr);
1834	pp = &ptr;
1835
1836	/*
1837	 * Iterate over each level in the btree, starting at the root.
1838	 * For each level above the leaves, find the key we need, based
1839	 * on the lookup record, then follow the corresponding block
1840	 * pointer down to the next level.
1841	 */
1842	for (level = cur->bc_nlevels - 1, diff = 1; level >= 0; level--) {
1843		/* Get the block we need to do the lookup on. */
1844		error = xfs_btree_lookup_get_block(cur, level, pp, &block);
1845		if (error)
1846			goto error0;
1847
1848		if (diff == 0) {
1849			/*
1850			 * If we already had a key match at a higher level, we
1851			 * know we need to use the first entry in this block.
1852			 */
1853			keyno = 1;
1854		} else {
1855			/* Otherwise search this block. Do a binary search. */
1856
1857			int	high;	/* high entry number */
1858			int	low;	/* low entry number */
1859
1860			/* Set low and high entry numbers, 1-based. */
1861			low = 1;
1862			high = xfs_btree_get_numrecs(block);
1863			if (!high) {
1864				/* Block is empty, must be an empty leaf. */
1865				if (level != 0 || cur->bc_nlevels != 1) {
1866					XFS_CORRUPTION_ERROR(__func__,
1867							XFS_ERRLEVEL_LOW,
1868							cur->bc_mp, block,
1869							sizeof(*block));
1870					return -EFSCORRUPTED;
1871				}
1872
1873				cur->bc_ptrs[0] = dir != XFS_LOOKUP_LE;
1874				*stat = 0;
1875				return 0;
1876			}
1877
1878			/* Binary search the block. */
1879			while (low <= high) {
1880				union xfs_btree_key	key;
1881				union xfs_btree_key	*kp;
1882
1883				XFS_BTREE_STATS_INC(cur, compare);
1884
1885				/* keyno is average of low and high. */
1886				keyno = (low + high) >> 1;
1887
1888				/* Get current search key */
1889				kp = xfs_lookup_get_search_key(cur, level,
1890						keyno, block, &key);
1891
1892				/*
1893				 * Compute difference to get next direction:
1894				 *  - less than, move right
1895				 *  - greater than, move left
1896				 *  - equal, we're done
1897				 */
1898				diff = cur->bc_ops->key_diff(cur, kp);
1899				if (diff < 0)
1900					low = keyno + 1;
1901				else if (diff > 0)
1902					high = keyno - 1;
1903				else
1904					break;
1905			}
1906		}
1907
1908		/*
1909		 * If there are more levels, set up for the next level
1910		 * by getting the block number and filling in the cursor.
1911		 */
1912		if (level > 0) {
1913			/*
1914			 * If we moved left, need the previous key number,
1915			 * unless there isn't one.
1916			 */
1917			if (diff > 0 && --keyno < 1)
1918				keyno = 1;
1919			pp = xfs_btree_ptr_addr(cur, keyno, block);
1920
1921			error = xfs_btree_debug_check_ptr(cur, pp, 0, level);
1922			if (error)
1923				goto error0;
1924
1925			cur->bc_ptrs[level] = keyno;
1926		}
1927	}
1928
1929	/* Done with the search. See if we need to adjust the results. */
1930	if (dir != XFS_LOOKUP_LE && diff < 0) {
1931		keyno++;
1932		/*
1933		 * If ge search and we went off the end of the block, but it's
1934		 * not the last block, we're in the wrong block.
1935		 */
1936		xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
1937		if (dir == XFS_LOOKUP_GE &&
1938		    keyno > xfs_btree_get_numrecs(block) &&
1939		    !xfs_btree_ptr_is_null(cur, &ptr)) {
1940			int	i;
1941
1942			cur->bc_ptrs[0] = keyno;
1943			error = xfs_btree_increment(cur, 0, &i);
1944			if (error)
1945				goto error0;
1946			if (XFS_IS_CORRUPT(cur->bc_mp, i != 1))
1947				return -EFSCORRUPTED;
1948			*stat = 1;
1949			return 0;
1950		}
1951	} else if (dir == XFS_LOOKUP_LE && diff > 0)
1952		keyno--;
1953	cur->bc_ptrs[0] = keyno;
1954
1955	/* Return if we succeeded or not. */
1956	if (keyno == 0 || keyno > xfs_btree_get_numrecs(block))
1957		*stat = 0;
1958	else if (dir != XFS_LOOKUP_EQ || diff == 0)
1959		*stat = 1;
1960	else
1961		*stat = 0;
1962	return 0;
1963
1964error0:
1965	return error;
1966}
1967
1968/* Find the high key storage area from a regular key. */
1969union xfs_btree_key *
1970xfs_btree_high_key_from_key(
1971	struct xfs_btree_cur	*cur,
1972	union xfs_btree_key	*key)
1973{
1974	ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
1975	return (union xfs_btree_key *)((char *)key +
1976			(cur->bc_ops->key_len / 2));
1977}
1978
1979/* Determine the low (and high if overlapped) keys of a leaf block */
1980STATIC void
1981xfs_btree_get_leaf_keys(
1982	struct xfs_btree_cur	*cur,
1983	struct xfs_btree_block	*block,
1984	union xfs_btree_key	*key)
1985{
1986	union xfs_btree_key	max_hkey;
1987	union xfs_btree_key	hkey;
1988	union xfs_btree_rec	*rec;
1989	union xfs_btree_key	*high;
1990	int			n;
1991
1992	rec = xfs_btree_rec_addr(cur, 1, block);
1993	cur->bc_ops->init_key_from_rec(key, rec);
1994
1995	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
1996
1997		cur->bc_ops->init_high_key_from_rec(&max_hkey, rec);
1998		for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
1999			rec = xfs_btree_rec_addr(cur, n, block);
2000			cur->bc_ops->init_high_key_from_rec(&hkey, rec);
2001			if (cur->bc_ops->diff_two_keys(cur, &hkey, &max_hkey)
2002					> 0)
2003				max_hkey = hkey;
2004		}
2005
2006		high = xfs_btree_high_key_from_key(cur, key);
2007		memcpy(high, &max_hkey, cur->bc_ops->key_len / 2);
2008	}
2009}
2010
2011/* Determine the low (and high if overlapped) keys of a node block */
2012STATIC void
2013xfs_btree_get_node_keys(
2014	struct xfs_btree_cur	*cur,
2015	struct xfs_btree_block	*block,
2016	union xfs_btree_key	*key)
2017{
2018	union xfs_btree_key	*hkey;
2019	union xfs_btree_key	*max_hkey;
2020	union xfs_btree_key	*high;
2021	int			n;
2022
2023	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2024		memcpy(key, xfs_btree_key_addr(cur, 1, block),
2025				cur->bc_ops->key_len / 2);
2026
2027		max_hkey = xfs_btree_high_key_addr(cur, 1, block);
2028		for (n = 2; n <= xfs_btree_get_numrecs(block); n++) {
2029			hkey = xfs_btree_high_key_addr(cur, n, block);
2030			if (cur->bc_ops->diff_two_keys(cur, hkey, max_hkey) > 0)
2031				max_hkey = hkey;
2032		}
2033
2034		high = xfs_btree_high_key_from_key(cur, key);
2035		memcpy(high, max_hkey, cur->bc_ops->key_len / 2);
2036	} else {
2037		memcpy(key, xfs_btree_key_addr(cur, 1, block),
2038				cur->bc_ops->key_len);
2039	}
2040}
2041
2042/* Derive the keys for any btree block. */
2043void
2044xfs_btree_get_keys(
2045	struct xfs_btree_cur	*cur,
2046	struct xfs_btree_block	*block,
2047	union xfs_btree_key	*key)
2048{
2049	if (be16_to_cpu(block->bb_level) == 0)
2050		xfs_btree_get_leaf_keys(cur, block, key);
2051	else
2052		xfs_btree_get_node_keys(cur, block, key);
2053}
2054
2055/*
2056 * Decide if we need to update the parent keys of a btree block.  For
2057 * a standard btree this is only necessary if we're updating the first
2058 * record/key.  For an overlapping btree, we must always update the
2059 * keys because the highest key can be in any of the records or keys
2060 * in the block.
2061 */
2062static inline bool
2063xfs_btree_needs_key_update(
2064	struct xfs_btree_cur	*cur,
2065	int			ptr)
2066{
2067	return (cur->bc_flags & XFS_BTREE_OVERLAPPING) || ptr == 1;
2068}
2069
2070/*
2071 * Update the low and high parent keys of the given level, progressing
2072 * towards the root.  If force_all is false, stop if the keys for a given
2073 * level do not need updating.
2074 */
2075STATIC int
2076__xfs_btree_updkeys(
2077	struct xfs_btree_cur	*cur,
2078	int			level,
2079	struct xfs_btree_block	*block,
2080	struct xfs_buf		*bp0,
2081	bool			force_all)
2082{
2083	union xfs_btree_key	key;	/* keys from current level */
2084	union xfs_btree_key	*lkey;	/* keys from the next level up */
2085	union xfs_btree_key	*hkey;
2086	union xfs_btree_key	*nlkey;	/* keys from the next level up */
2087	union xfs_btree_key	*nhkey;
2088	struct xfs_buf		*bp;
2089	int			ptr;
2090
2091	ASSERT(cur->bc_flags & XFS_BTREE_OVERLAPPING);
2092
2093	/* Exit if there aren't any parent levels to update. */
2094	if (level + 1 >= cur->bc_nlevels)
2095		return 0;
2096
2097	trace_xfs_btree_updkeys(cur, level, bp0);
2098
2099	lkey = &key;
2100	hkey = xfs_btree_high_key_from_key(cur, lkey);
2101	xfs_btree_get_keys(cur, block, lkey);
2102	for (level++; level < cur->bc_nlevels; level++) {
2103#ifdef DEBUG
2104		int		error;
2105#endif
2106		block = xfs_btree_get_block(cur, level, &bp);
2107		trace_xfs_btree_updkeys(cur, level, bp);
2108#ifdef DEBUG
2109		error = xfs_btree_check_block(cur, block, level, bp);
2110		if (error)
2111			return error;
2112#endif
2113		ptr = cur->bc_ptrs[level];
2114		nlkey = xfs_btree_key_addr(cur, ptr, block);
2115		nhkey = xfs_btree_high_key_addr(cur, ptr, block);
2116		if (!force_all &&
2117		    !(cur->bc_ops->diff_two_keys(cur, nlkey, lkey) != 0 ||
2118		      cur->bc_ops->diff_two_keys(cur, nhkey, hkey) != 0))
2119			break;
2120		xfs_btree_copy_keys(cur, nlkey, lkey, 1);
2121		xfs_btree_log_keys(cur, bp, ptr, ptr);
2122		if (level + 1 >= cur->bc_nlevels)
2123			break;
2124		xfs_btree_get_node_keys(cur, block, lkey);
2125	}
2126
2127	return 0;
2128}
2129
2130/* Update all the keys from some level in cursor back to the root. */
2131STATIC int
2132xfs_btree_updkeys_force(
2133	struct xfs_btree_cur	*cur,
2134	int			level)
2135{
2136	struct xfs_buf		*bp;
2137	struct xfs_btree_block	*block;
2138
2139	block = xfs_btree_get_block(cur, level, &bp);
2140	return __xfs_btree_updkeys(cur, level, block, bp, true);
2141}
2142
2143/*
2144 * Update the parent keys of the given level, progressing towards the root.
2145 */
2146STATIC int
2147xfs_btree_update_keys(
2148	struct xfs_btree_cur	*cur,
2149	int			level)
2150{
2151	struct xfs_btree_block	*block;
2152	struct xfs_buf		*bp;
2153	union xfs_btree_key	*kp;
2154	union xfs_btree_key	key;
2155	int			ptr;
2156
2157	ASSERT(level >= 0);
2158
2159	block = xfs_btree_get_block(cur, level, &bp);
2160	if (cur->bc_flags & XFS_BTREE_OVERLAPPING)
2161		return __xfs_btree_updkeys(cur, level, block, bp, false);
2162
2163	/*
2164	 * Go up the tree from this level toward the root.
2165	 * At each level, update the key value to the value input.
2166	 * Stop when we reach a level where the cursor isn't pointing
2167	 * at the first entry in the block.
2168	 */
2169	xfs_btree_get_keys(cur, block, &key);
2170	for (level++, ptr = 1; ptr == 1 && level < cur->bc_nlevels; level++) {
2171#ifdef DEBUG
2172		int		error;
2173#endif
2174		block = xfs_btree_get_block(cur, level, &bp);
2175#ifdef DEBUG
2176		error = xfs_btree_check_block(cur, block, level, bp);
2177		if (error)
2178			return error;
2179#endif
2180		ptr = cur->bc_ptrs[level];
2181		kp = xfs_btree_key_addr(cur, ptr, block);
2182		xfs_btree_copy_keys(cur, kp, &key, 1);
2183		xfs_btree_log_keys(cur, bp, ptr, ptr);
2184	}
2185
2186	return 0;
2187}
2188
2189/*
2190 * Update the record referred to by cur to the value in the
2191 * given record. This either works (return 0) or gets an
2192 * EFSCORRUPTED error.
2193 */
2194int
2195xfs_btree_update(
2196	struct xfs_btree_cur	*cur,
2197	union xfs_btree_rec	*rec)
2198{
2199	struct xfs_btree_block	*block;
2200	struct xfs_buf		*bp;
2201	int			error;
2202	int			ptr;
2203	union xfs_btree_rec	*rp;
2204
2205	/* Pick up the current block. */
2206	block = xfs_btree_get_block(cur, 0, &bp);
2207
2208#ifdef DEBUG
2209	error = xfs_btree_check_block(cur, block, 0, bp);
2210	if (error)
2211		goto error0;
2212#endif
2213	/* Get the address of the rec to be updated. */
2214	ptr = cur->bc_ptrs[0];
2215	rp = xfs_btree_rec_addr(cur, ptr, block);
2216
2217	/* Fill in the new contents and log them. */
2218	xfs_btree_copy_recs(cur, rp, rec, 1);
2219	xfs_btree_log_recs(cur, bp, ptr, ptr);
2220
2221	/*
2222	 * If we are tracking the last record in the tree and
2223	 * we are at the far right edge of the tree, update it.
2224	 */
2225	if (xfs_btree_is_lastrec(cur, block, 0)) {
2226		cur->bc_ops->update_lastrec(cur, block, rec,
2227					    ptr, LASTREC_UPDATE);
2228	}
2229
2230	/* Pass new key value up to our parent. */
2231	if (xfs_btree_needs_key_update(cur, ptr)) {
2232		error = xfs_btree_update_keys(cur, 0);
2233		if (error)
2234			goto error0;
2235	}
2236
2237	return 0;
2238
2239error0:
2240	return error;
2241}
2242
2243/*
2244 * Move 1 record left from cur/level if possible.
2245 * Update cur to reflect the new path.
2246 */
2247STATIC int					/* error */
2248xfs_btree_lshift(
2249	struct xfs_btree_cur	*cur,
2250	int			level,
2251	int			*stat)		/* success/failure */
2252{
2253	struct xfs_buf		*lbp;		/* left buffer pointer */
2254	struct xfs_btree_block	*left;		/* left btree block */
2255	int			lrecs;		/* left record count */
2256	struct xfs_buf		*rbp;		/* right buffer pointer */
2257	struct xfs_btree_block	*right;		/* right btree block */
2258	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
2259	int			rrecs;		/* right record count */
2260	union xfs_btree_ptr	lptr;		/* left btree pointer */
2261	union xfs_btree_key	*rkp = NULL;	/* right btree key */
2262	union xfs_btree_ptr	*rpp = NULL;	/* right address pointer */
2263	union xfs_btree_rec	*rrp = NULL;	/* right record pointer */
2264	int			error;		/* error return value */
2265	int			i;
2266
2267	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2268	    level == cur->bc_nlevels - 1)
2269		goto out0;
2270
2271	/* Set up variables for this block as "right". */
2272	right = xfs_btree_get_block(cur, level, &rbp);
2273
2274#ifdef DEBUG
2275	error = xfs_btree_check_block(cur, right, level, rbp);
2276	if (error)
2277		goto error0;
2278#endif
2279
2280	/* If we've got no left sibling then we can't shift an entry left. */
2281	xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2282	if (xfs_btree_ptr_is_null(cur, &lptr))
2283		goto out0;
2284
2285	/*
2286	 * If the cursor entry is the one that would be moved, don't
2287	 * do it... it's too complicated.
2288	 */
2289	if (cur->bc_ptrs[level] <= 1)
2290		goto out0;
2291
2292	/* Set up the left neighbor as "left". */
2293	error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
2294	if (error)
2295		goto error0;
2296
2297	/* If it's full, it can't take another entry. */
2298	lrecs = xfs_btree_get_numrecs(left);
2299	if (lrecs == cur->bc_ops->get_maxrecs(cur, level))
2300		goto out0;
2301
2302	rrecs = xfs_btree_get_numrecs(right);
2303
2304	/*
2305	 * We add one entry to the left side and remove one for the right side.
2306	 * Account for it here, the changes will be updated on disk and logged
2307	 * later.
2308	 */
2309	lrecs++;
2310	rrecs--;
2311
2312	XFS_BTREE_STATS_INC(cur, lshift);
2313	XFS_BTREE_STATS_ADD(cur, moves, 1);
2314
2315	/*
2316	 * If non-leaf, copy a key and a ptr to the left block.
2317	 * Log the changes to the left block.
2318	 */
2319	if (level > 0) {
2320		/* It's a non-leaf.  Move keys and pointers. */
2321		union xfs_btree_key	*lkp;	/* left btree key */
2322		union xfs_btree_ptr	*lpp;	/* left address pointer */
2323
2324		lkp = xfs_btree_key_addr(cur, lrecs, left);
2325		rkp = xfs_btree_key_addr(cur, 1, right);
2326
2327		lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2328		rpp = xfs_btree_ptr_addr(cur, 1, right);
2329
2330		error = xfs_btree_debug_check_ptr(cur, rpp, 0, level);
2331		if (error)
2332			goto error0;
2333
2334		xfs_btree_copy_keys(cur, lkp, rkp, 1);
2335		xfs_btree_copy_ptrs(cur, lpp, rpp, 1);
2336
2337		xfs_btree_log_keys(cur, lbp, lrecs, lrecs);
2338		xfs_btree_log_ptrs(cur, lbp, lrecs, lrecs);
2339
2340		ASSERT(cur->bc_ops->keys_inorder(cur,
2341			xfs_btree_key_addr(cur, lrecs - 1, left), lkp));
2342	} else {
2343		/* It's a leaf.  Move records.  */
2344		union xfs_btree_rec	*lrp;	/* left record pointer */
2345
2346		lrp = xfs_btree_rec_addr(cur, lrecs, left);
2347		rrp = xfs_btree_rec_addr(cur, 1, right);
2348
2349		xfs_btree_copy_recs(cur, lrp, rrp, 1);
2350		xfs_btree_log_recs(cur, lbp, lrecs, lrecs);
2351
2352		ASSERT(cur->bc_ops->recs_inorder(cur,
2353			xfs_btree_rec_addr(cur, lrecs - 1, left), lrp));
2354	}
2355
2356	xfs_btree_set_numrecs(left, lrecs);
2357	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2358
2359	xfs_btree_set_numrecs(right, rrecs);
2360	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2361
2362	/*
2363	 * Slide the contents of right down one entry.
2364	 */
2365	XFS_BTREE_STATS_ADD(cur, moves, rrecs - 1);
2366	if (level > 0) {
2367		/* It's a nonleaf. operate on keys and ptrs */
2368		for (i = 0; i < rrecs; i++) {
2369			error = xfs_btree_debug_check_ptr(cur, rpp, i + 1, level);
2370			if (error)
2371				goto error0;
2372		}
2373
2374		xfs_btree_shift_keys(cur,
2375				xfs_btree_key_addr(cur, 2, right),
2376				-1, rrecs);
2377		xfs_btree_shift_ptrs(cur,
2378				xfs_btree_ptr_addr(cur, 2, right),
2379				-1, rrecs);
2380
2381		xfs_btree_log_keys(cur, rbp, 1, rrecs);
2382		xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2383	} else {
2384		/* It's a leaf. operate on records */
2385		xfs_btree_shift_recs(cur,
2386			xfs_btree_rec_addr(cur, 2, right),
2387			-1, rrecs);
2388		xfs_btree_log_recs(cur, rbp, 1, rrecs);
2389	}
2390
2391	/*
2392	 * Using a temporary cursor, update the parent key values of the
2393	 * block on the left.
2394	 */
2395	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2396		error = xfs_btree_dup_cursor(cur, &tcur);
2397		if (error)
2398			goto error0;
2399		i = xfs_btree_firstrec(tcur, level);
2400		if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2401			error = -EFSCORRUPTED;
2402			goto error0;
2403		}
2404
2405		error = xfs_btree_decrement(tcur, level, &i);
2406		if (error)
2407			goto error1;
2408
2409		/* Update the parent high keys of the left block, if needed. */
2410		error = xfs_btree_update_keys(tcur, level);
2411		if (error)
2412			goto error1;
2413
2414		xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2415	}
2416
2417	/* Update the parent keys of the right block. */
2418	error = xfs_btree_update_keys(cur, level);
2419	if (error)
2420		goto error0;
2421
2422	/* Slide the cursor value left one. */
2423	cur->bc_ptrs[level]--;
2424
2425	*stat = 1;
2426	return 0;
2427
2428out0:
2429	*stat = 0;
2430	return 0;
2431
2432error0:
2433	return error;
2434
2435error1:
2436	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2437	return error;
2438}
2439
2440/*
2441 * Move 1 record right from cur/level if possible.
2442 * Update cur to reflect the new path.
2443 */
2444STATIC int					/* error */
2445xfs_btree_rshift(
2446	struct xfs_btree_cur	*cur,
2447	int			level,
2448	int			*stat)		/* success/failure */
2449{
2450	struct xfs_buf		*lbp;		/* left buffer pointer */
2451	struct xfs_btree_block	*left;		/* left btree block */
2452	struct xfs_buf		*rbp;		/* right buffer pointer */
2453	struct xfs_btree_block	*right;		/* right btree block */
2454	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
2455	union xfs_btree_ptr	rptr;		/* right block pointer */
2456	union xfs_btree_key	*rkp;		/* right btree key */
2457	int			rrecs;		/* right record count */
2458	int			lrecs;		/* left record count */
2459	int			error;		/* error return value */
2460	int			i;		/* loop counter */
2461
2462	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
2463	    (level == cur->bc_nlevels - 1))
2464		goto out0;
2465
2466	/* Set up variables for this block as "left". */
2467	left = xfs_btree_get_block(cur, level, &lbp);
2468
2469#ifdef DEBUG
2470	error = xfs_btree_check_block(cur, left, level, lbp);
2471	if (error)
2472		goto error0;
2473#endif
2474
2475	/* If we've got no right sibling then we can't shift an entry right. */
2476	xfs_btree_get_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2477	if (xfs_btree_ptr_is_null(cur, &rptr))
2478		goto out0;
2479
2480	/*
2481	 * If the cursor entry is the one that would be moved, don't
2482	 * do it... it's too complicated.
2483	 */
2484	lrecs = xfs_btree_get_numrecs(left);
2485	if (cur->bc_ptrs[level] >= lrecs)
2486		goto out0;
2487
2488	/* Set up the right neighbor as "right". */
2489	error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
2490	if (error)
2491		goto error0;
2492
2493	/* If it's full, it can't take another entry. */
2494	rrecs = xfs_btree_get_numrecs(right);
2495	if (rrecs == cur->bc_ops->get_maxrecs(cur, level))
2496		goto out0;
2497
2498	XFS_BTREE_STATS_INC(cur, rshift);
2499	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2500
2501	/*
2502	 * Make a hole at the start of the right neighbor block, then
2503	 * copy the last left block entry to the hole.
2504	 */
2505	if (level > 0) {
2506		/* It's a nonleaf. make a hole in the keys and ptrs */
2507		union xfs_btree_key	*lkp;
2508		union xfs_btree_ptr	*lpp;
2509		union xfs_btree_ptr	*rpp;
2510
2511		lkp = xfs_btree_key_addr(cur, lrecs, left);
2512		lpp = xfs_btree_ptr_addr(cur, lrecs, left);
2513		rkp = xfs_btree_key_addr(cur, 1, right);
2514		rpp = xfs_btree_ptr_addr(cur, 1, right);
2515
2516		for (i = rrecs - 1; i >= 0; i--) {
2517			error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
2518			if (error)
2519				goto error0;
2520		}
2521
2522		xfs_btree_shift_keys(cur, rkp, 1, rrecs);
2523		xfs_btree_shift_ptrs(cur, rpp, 1, rrecs);
2524
2525		error = xfs_btree_debug_check_ptr(cur, lpp, 0, level);
2526		if (error)
2527			goto error0;
2528
2529		/* Now put the new data in, and log it. */
2530		xfs_btree_copy_keys(cur, rkp, lkp, 1);
2531		xfs_btree_copy_ptrs(cur, rpp, lpp, 1);
2532
2533		xfs_btree_log_keys(cur, rbp, 1, rrecs + 1);
2534		xfs_btree_log_ptrs(cur, rbp, 1, rrecs + 1);
2535
2536		ASSERT(cur->bc_ops->keys_inorder(cur, rkp,
2537			xfs_btree_key_addr(cur, 2, right)));
2538	} else {
2539		/* It's a leaf. make a hole in the records */
2540		union xfs_btree_rec	*lrp;
2541		union xfs_btree_rec	*rrp;
2542
2543		lrp = xfs_btree_rec_addr(cur, lrecs, left);
2544		rrp = xfs_btree_rec_addr(cur, 1, right);
2545
2546		xfs_btree_shift_recs(cur, rrp, 1, rrecs);
2547
2548		/* Now put the new data in, and log it. */
2549		xfs_btree_copy_recs(cur, rrp, lrp, 1);
2550		xfs_btree_log_recs(cur, rbp, 1, rrecs + 1);
2551	}
2552
2553	/*
2554	 * Decrement and log left's numrecs, bump and log right's numrecs.
2555	 */
2556	xfs_btree_set_numrecs(left, --lrecs);
2557	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS);
2558
2559	xfs_btree_set_numrecs(right, ++rrecs);
2560	xfs_btree_log_block(cur, rbp, XFS_BB_NUMRECS);
2561
2562	/*
2563	 * Using a temporary cursor, update the parent key values of the
2564	 * block on the right.
2565	 */
2566	error = xfs_btree_dup_cursor(cur, &tcur);
2567	if (error)
2568		goto error0;
2569	i = xfs_btree_lastrec(tcur, level);
2570	if (XFS_IS_CORRUPT(tcur->bc_mp, i != 1)) {
2571		error = -EFSCORRUPTED;
2572		goto error0;
2573	}
2574
2575	error = xfs_btree_increment(tcur, level, &i);
2576	if (error)
2577		goto error1;
2578
2579	/* Update the parent high keys of the left block, if needed. */
2580	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2581		error = xfs_btree_update_keys(cur, level);
2582		if (error)
2583			goto error1;
2584	}
2585
2586	/* Update the parent keys of the right block. */
2587	error = xfs_btree_update_keys(tcur, level);
2588	if (error)
2589		goto error1;
2590
2591	xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
2592
2593	*stat = 1;
2594	return 0;
2595
2596out0:
2597	*stat = 0;
2598	return 0;
2599
2600error0:
2601	return error;
2602
2603error1:
2604	xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
2605	return error;
2606}
2607
2608/*
2609 * Split cur/level block in half.
2610 * Return new block number and the key to its first
2611 * record (to be inserted into parent).
2612 */
2613STATIC int					/* error */
2614__xfs_btree_split(
2615	struct xfs_btree_cur	*cur,
2616	int			level,
2617	union xfs_btree_ptr	*ptrp,
2618	union xfs_btree_key	*key,
2619	struct xfs_btree_cur	**curp,
2620	int			*stat)		/* success/failure */
2621{
2622	union xfs_btree_ptr	lptr;		/* left sibling block ptr */
2623	struct xfs_buf		*lbp;		/* left buffer pointer */
2624	struct xfs_btree_block	*left;		/* left btree block */
2625	union xfs_btree_ptr	rptr;		/* right sibling block ptr */
2626	struct xfs_buf		*rbp;		/* right buffer pointer */
2627	struct xfs_btree_block	*right;		/* right btree block */
2628	union xfs_btree_ptr	rrptr;		/* right-right sibling ptr */
2629	struct xfs_buf		*rrbp;		/* right-right buffer pointer */
2630	struct xfs_btree_block	*rrblock;	/* right-right btree block */
2631	int			lrecs;
2632	int			rrecs;
2633	int			src_index;
2634	int			error;		/* error return value */
2635	int			i;
2636
2637	XFS_BTREE_STATS_INC(cur, split);
2638
2639	/* Set up left block (current one). */
2640	left = xfs_btree_get_block(cur, level, &lbp);
2641
2642#ifdef DEBUG
2643	error = xfs_btree_check_block(cur, left, level, lbp);
2644	if (error)
2645		goto error0;
2646#endif
2647
2648	xfs_btree_buf_to_ptr(cur, lbp, &lptr);
2649
2650	/* Allocate the new block. If we can't do it, we're toast. Give up. */
2651	error = cur->bc_ops->alloc_block(cur, &lptr, &rptr, stat);
2652	if (error)
2653		goto error0;
2654	if (*stat == 0)
2655		goto out0;
2656	XFS_BTREE_STATS_INC(cur, alloc);
2657
2658	/* Set up the new block as "right". */
2659	error = xfs_btree_get_buf_block(cur, &rptr, &right, &rbp);
2660	if (error)
2661		goto error0;
2662
2663	/* Fill in the btree header for the new right block. */
2664	xfs_btree_init_block_cur(cur, rbp, xfs_btree_get_level(left), 0);
2665
2666	/*
2667	 * Split the entries between the old and the new block evenly.
2668	 * Make sure that if there's an odd number of entries now, that
2669	 * each new block will have the same number of entries.
2670	 */
2671	lrecs = xfs_btree_get_numrecs(left);
2672	rrecs = lrecs / 2;
2673	if ((lrecs & 1) && cur->bc_ptrs[level] <= rrecs + 1)
2674		rrecs++;
2675	src_index = (lrecs - rrecs + 1);
2676
2677	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
2678
2679	/* Adjust numrecs for the later get_*_keys() calls. */
2680	lrecs -= rrecs;
2681	xfs_btree_set_numrecs(left, lrecs);
2682	xfs_btree_set_numrecs(right, xfs_btree_get_numrecs(right) + rrecs);
2683
2684	/*
2685	 * Copy btree block entries from the left block over to the
2686	 * new block, the right. Update the right block and log the
2687	 * changes.
2688	 */
2689	if (level > 0) {
2690		/* It's a non-leaf.  Move keys and pointers. */
2691		union xfs_btree_key	*lkp;	/* left btree key */
2692		union xfs_btree_ptr	*lpp;	/* left address pointer */
2693		union xfs_btree_key	*rkp;	/* right btree key */
2694		union xfs_btree_ptr	*rpp;	/* right address pointer */
2695
2696		lkp = xfs_btree_key_addr(cur, src_index, left);
2697		lpp = xfs_btree_ptr_addr(cur, src_index, left);
2698		rkp = xfs_btree_key_addr(cur, 1, right);
2699		rpp = xfs_btree_ptr_addr(cur, 1, right);
2700
2701		for (i = src_index; i < rrecs; i++) {
2702			error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
2703			if (error)
2704				goto error0;
2705		}
2706
2707		/* Copy the keys & pointers to the new block. */
2708		xfs_btree_copy_keys(cur, rkp, lkp, rrecs);
2709		xfs_btree_copy_ptrs(cur, rpp, lpp, rrecs);
2710
2711		xfs_btree_log_keys(cur, rbp, 1, rrecs);
2712		xfs_btree_log_ptrs(cur, rbp, 1, rrecs);
2713
2714		/* Stash the keys of the new block for later insertion. */
2715		xfs_btree_get_node_keys(cur, right, key);
2716	} else {
2717		/* It's a leaf.  Move records.  */
2718		union xfs_btree_rec	*lrp;	/* left record pointer */
2719		union xfs_btree_rec	*rrp;	/* right record pointer */
2720
2721		lrp = xfs_btree_rec_addr(cur, src_index, left);
2722		rrp = xfs_btree_rec_addr(cur, 1, right);
2723
2724		/* Copy records to the new block. */
2725		xfs_btree_copy_recs(cur, rrp, lrp, rrecs);
2726		xfs_btree_log_recs(cur, rbp, 1, rrecs);
2727
2728		/* Stash the keys of the new block for later insertion. */
2729		xfs_btree_get_leaf_keys(cur, right, key);
2730	}
2731
2732	/*
2733	 * Find the left block number by looking in the buffer.
2734	 * Adjust sibling pointers.
2735	 */
2736	xfs_btree_get_sibling(cur, left, &rrptr, XFS_BB_RIGHTSIB);
2737	xfs_btree_set_sibling(cur, right, &rrptr, XFS_BB_RIGHTSIB);
2738	xfs_btree_set_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
2739	xfs_btree_set_sibling(cur, left, &rptr, XFS_BB_RIGHTSIB);
2740
2741	xfs_btree_log_block(cur, rbp, XFS_BB_ALL_BITS);
2742	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
2743
2744	/*
2745	 * If there's a block to the new block's right, make that block
2746	 * point back to right instead of to left.
2747	 */
2748	if (!xfs_btree_ptr_is_null(cur, &rrptr)) {
2749		error = xfs_btree_read_buf_block(cur, &rrptr,
2750							0, &rrblock, &rrbp);
2751		if (error)
2752			goto error0;
2753		xfs_btree_set_sibling(cur, rrblock, &rptr, XFS_BB_LEFTSIB);
2754		xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
2755	}
2756
2757	/* Update the parent high keys of the left block, if needed. */
2758	if (cur->bc_flags & XFS_BTREE_OVERLAPPING) {
2759		error = xfs_btree_update_keys(cur, level);
2760		if (error)
2761			goto error0;
2762	}
2763
2764	/*
2765	 * If the cursor is really in the right block, move it there.
2766	 * If it's just pointing past the last entry in left, then we'll
2767	 * insert there, so don't change anything in that case.
2768	 */
2769	if (cur->bc_ptrs[level] > lrecs + 1) {
2770		xfs_btree_setbuf(cur, level, rbp);
2771		cur->bc_ptrs[level] -= lrecs;
2772	}
2773	/*
2774	 * If there are more levels, we'll need another cursor which refers
2775	 * the right block, no matter where this cursor was.
2776	 */
2777	if (level + 1 < cur->bc_nlevels) {
2778		error = xfs_btree_dup_cursor(cur, curp);
2779		if (error)
2780			goto error0;
2781		(*curp)->bc_ptrs[level + 1]++;
2782	}
2783	*ptrp = rptr;
2784	*stat = 1;
2785	return 0;
2786out0:
2787	*stat = 0;
2788	return 0;
2789
2790error0:
2791	return error;
2792}
2793
2794struct xfs_btree_split_args {
2795	struct xfs_btree_cur	*cur;
2796	int			level;
2797	union xfs_btree_ptr	*ptrp;
2798	union xfs_btree_key	*key;
2799	struct xfs_btree_cur	**curp;
2800	int			*stat;		/* success/failure */
2801	int			result;
2802	bool			kswapd;	/* allocation in kswapd context */
2803	struct completion	*done;
2804	struct work_struct	work;
2805};
2806
2807/*
2808 * Stack switching interfaces for allocation
2809 */
2810static void
2811xfs_btree_split_worker(
2812	struct work_struct	*work)
2813{
2814	struct xfs_btree_split_args	*args = container_of(work,
2815						struct xfs_btree_split_args, work);
2816	unsigned long		pflags;
2817	unsigned long		new_pflags = PF_MEMALLOC_NOFS;
2818
2819	/*
2820	 * we are in a transaction context here, but may also be doing work
2821	 * in kswapd context, and hence we may need to inherit that state
2822	 * temporarily to ensure that we don't block waiting for memory reclaim
2823	 * in any way.
2824	 */
2825	if (args->kswapd)
2826		new_pflags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD;
2827
2828	current_set_flags_nested(&pflags, new_pflags);
2829
2830	args->result = __xfs_btree_split(args->cur, args->level, args->ptrp,
2831					 args->key, args->curp, args->stat);
2832	complete(args->done);
2833
2834	current_restore_flags_nested(&pflags, new_pflags);
2835}
2836
2837/*
2838 * BMBT split requests often come in with little stack to work on. Push
2839 * them off to a worker thread so there is lots of stack to use. For the other
2840 * btree types, just call directly to avoid the context switch overhead here.
2841 */
2842STATIC int					/* error */
2843xfs_btree_split(
2844	struct xfs_btree_cur	*cur,
2845	int			level,
2846	union xfs_btree_ptr	*ptrp,
2847	union xfs_btree_key	*key,
2848	struct xfs_btree_cur	**curp,
2849	int			*stat)		/* success/failure */
2850{
2851	struct xfs_btree_split_args	args;
2852	DECLARE_COMPLETION_ONSTACK(done);
2853
2854	if (cur->bc_btnum != XFS_BTNUM_BMAP)
2855		return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
2856
2857	args.cur = cur;
2858	args.level = level;
2859	args.ptrp = ptrp;
2860	args.key = key;
2861	args.curp = curp;
2862	args.stat = stat;
2863	args.done = &done;
2864	args.kswapd = current_is_kswapd();
2865	INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
2866	queue_work(xfs_alloc_wq, &args.work);
2867	wait_for_completion(&done);
2868	destroy_work_on_stack(&args.work);
2869	return args.result;
2870}
2871
2872
2873/*
2874 * Copy the old inode root contents into a real block and make the
2875 * broot point to it.
2876 */
2877int						/* error */
2878xfs_btree_new_iroot(
2879	struct xfs_btree_cur	*cur,		/* btree cursor */
2880	int			*logflags,	/* logging flags for inode */
2881	int			*stat)		/* return status - 0 fail */
2882{
2883	struct xfs_buf		*cbp;		/* buffer for cblock */
2884	struct xfs_btree_block	*block;		/* btree block */
2885	struct xfs_btree_block	*cblock;	/* child btree block */
2886	union xfs_btree_key	*ckp;		/* child key pointer */
2887	union xfs_btree_ptr	*cpp;		/* child ptr pointer */
2888	union xfs_btree_key	*kp;		/* pointer to btree key */
2889	union xfs_btree_ptr	*pp;		/* pointer to block addr */
2890	union xfs_btree_ptr	nptr;		/* new block addr */
2891	int			level;		/* btree level */
2892	int			error;		/* error return code */
2893	int			i;		/* loop counter */
2894
2895	XFS_BTREE_STATS_INC(cur, newroot);
2896
2897	ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
2898
2899	level = cur->bc_nlevels - 1;
2900
2901	block = xfs_btree_get_iroot(cur);
2902	pp = xfs_btree_ptr_addr(cur, 1, block);
2903
2904	/* Allocate the new block. If we can't do it, we're toast. Give up. */
2905	error = cur->bc_ops->alloc_block(cur, pp, &nptr, stat);
2906	if (error)
2907		goto error0;
2908	if (*stat == 0)
2909		return 0;
2910
2911	XFS_BTREE_STATS_INC(cur, alloc);
2912
2913	/* Copy the root into a real block. */
2914	error = xfs_btree_get_buf_block(cur, &nptr, &cblock, &cbp);
2915	if (error)
2916		goto error0;
2917
2918	/*
2919	 * we can't just memcpy() the root in for CRC enabled btree blocks.
2920	 * In that case have to also ensure the blkno remains correct
2921	 */
2922	memcpy(cblock, block, xfs_btree_block_len(cur));
2923	if (cur->bc_flags & XFS_BTREE_CRC_BLOCKS) {
2924		if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
2925			cblock->bb_u.l.bb_blkno = cpu_to_be64(cbp->b_bn);
2926		else
2927			cblock->bb_u.s.bb_blkno = cpu_to_be64(cbp->b_bn);
2928	}
2929
2930	be16_add_cpu(&block->bb_level, 1);
2931	xfs_btree_set_numrecs(block, 1);
2932	cur->bc_nlevels++;
2933	cur->bc_ptrs[level + 1] = 1;
2934
2935	kp = xfs_btree_key_addr(cur, 1, block);
2936	ckp = xfs_btree_key_addr(cur, 1, cblock);
2937	xfs_btree_copy_keys(cur, ckp, kp, xfs_btree_get_numrecs(cblock));
2938
2939	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
2940	for (i = 0; i < be16_to_cpu(cblock->bb_numrecs); i++) {
2941		error = xfs_btree_debug_check_ptr(cur, pp, i, level);
2942		if (error)
2943			goto error0;
2944	}
2945
2946	xfs_btree_copy_ptrs(cur, cpp, pp, xfs_btree_get_numrecs(cblock));
2947
2948	error = xfs_btree_debug_check_ptr(cur, &nptr, 0, level);
2949	if (error)
2950		goto error0;
2951
2952	xfs_btree_copy_ptrs(cur, pp, &nptr, 1);
2953
2954	xfs_iroot_realloc(cur->bc_ino.ip,
2955			  1 - xfs_btree_get_numrecs(cblock),
2956			  cur->bc_ino.whichfork);
2957
2958	xfs_btree_setbuf(cur, level, cbp);
2959
2960	/*
2961	 * Do all this logging at the end so that
2962	 * the root is at the right level.
2963	 */
2964	xfs_btree_log_block(cur, cbp, XFS_BB_ALL_BITS);
2965	xfs_btree_log_keys(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2966	xfs_btree_log_ptrs(cur, cbp, 1, be16_to_cpu(cblock->bb_numrecs));
2967
2968	*logflags |=
2969		XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork);
2970	*stat = 1;
2971	return 0;
2972error0:
2973	return error;
2974}
2975
2976/*
2977 * Allocate a new root block, fill it in.
2978 */
2979STATIC int				/* error */
2980xfs_btree_new_root(
2981	struct xfs_btree_cur	*cur,	/* btree cursor */
2982	int			*stat)	/* success/failure */
2983{
2984	struct xfs_btree_block	*block;	/* one half of the old root block */
2985	struct xfs_buf		*bp;	/* buffer containing block */
2986	int			error;	/* error return value */
2987	struct xfs_buf		*lbp;	/* left buffer pointer */
2988	struct xfs_btree_block	*left;	/* left btree block */
2989	struct xfs_buf		*nbp;	/* new (root) buffer */
2990	struct xfs_btree_block	*new;	/* new (root) btree block */
2991	int			nptr;	/* new value for key index, 1 or 2 */
2992	struct xfs_buf		*rbp;	/* right buffer pointer */
2993	struct xfs_btree_block	*right;	/* right btree block */
2994	union xfs_btree_ptr	rptr;
2995	union xfs_btree_ptr	lptr;
2996
2997	XFS_BTREE_STATS_INC(cur, newroot);
2998
2999	/* initialise our start point from the cursor */
3000	cur->bc_ops->init_ptr_from_cur(cur, &rptr);
3001
3002	/* Allocate the new block. If we can't do it, we're toast. Give up. */
3003	error = cur->bc_ops->alloc_block(cur, &rptr, &lptr, stat);
3004	if (error)
3005		goto error0;
3006	if (*stat == 0)
3007		goto out0;
3008	XFS_BTREE_STATS_INC(cur, alloc);
3009
3010	/* Set up the new block. */
3011	error = xfs_btree_get_buf_block(cur, &lptr, &new, &nbp);
3012	if (error)
3013		goto error0;
3014
3015	/* Set the root in the holding structure  increasing the level by 1. */
3016	cur->bc_ops->set_root(cur, &lptr, 1);
3017
3018	/*
3019	 * At the previous root level there are now two blocks: the old root,
3020	 * and the new block generated when it was split.  We don't know which
3021	 * one the cursor is pointing at, so we set up variables "left" and
3022	 * "right" for each case.
3023	 */
3024	block = xfs_btree_get_block(cur, cur->bc_nlevels - 1, &bp);
3025
3026#ifdef DEBUG
3027	error = xfs_btree_check_block(cur, block, cur->bc_nlevels - 1, bp);
3028	if (error)
3029		goto error0;
3030#endif
3031
3032	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3033	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3034		/* Our block is left, pick up the right block. */
3035		lbp = bp;
3036		xfs_btree_buf_to_ptr(cur, lbp, &lptr);
3037		left = block;
3038		error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
3039		if (error)
3040			goto error0;
3041		bp = rbp;
3042		nptr = 1;
3043	} else {
3044		/* Our block is right, pick up the left block. */
3045		rbp = bp;
3046		xfs_btree_buf_to_ptr(cur, rbp, &rptr);
3047		right = block;
3048		xfs_btree_get_sibling(cur, right, &lptr, XFS_BB_LEFTSIB);
3049		error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
3050		if (error)
3051			goto error0;
3052		bp = lbp;
3053		nptr = 2;
3054	}
3055
3056	/* Fill in the new block's btree header and log it. */
3057	xfs_btree_init_block_cur(cur, nbp, cur->bc_nlevels, 2);
3058	xfs_btree_log_block(cur, nbp, XFS_BB_ALL_BITS);
3059	ASSERT(!xfs_btree_ptr_is_null(cur, &lptr) &&
3060			!xfs_btree_ptr_is_null(cur, &rptr));
3061
3062	/* Fill in the key data in the new root. */
3063	if (xfs_btree_get_level(left) > 0) {
3064		/*
3065		 * Get the keys for the left block's keys and put them directly
3066		 * in the parent block.  Do the same for the right block.
3067		 */
3068		xfs_btree_get_node_keys(cur, left,
3069				xfs_btree_key_addr(cur, 1, new));
3070		xfs_btree_get_node_keys(cur, right,
3071				xfs_btree_key_addr(cur, 2, new));
3072	} else {
3073		/*
3074		 * Get the keys for the left block's records and put them
3075		 * directly in the parent block.  Do the same for the right
3076		 * block.
3077		 */
3078		xfs_btree_get_leaf_keys(cur, left,
3079			xfs_btree_key_addr(cur, 1, new));
3080		xfs_btree_get_leaf_keys(cur, right,
3081			xfs_btree_key_addr(cur, 2, new));
3082	}
3083	xfs_btree_log_keys(cur, nbp, 1, 2);
3084
3085	/* Fill in the pointer data in the new root. */
3086	xfs_btree_copy_ptrs(cur,
3087		xfs_btree_ptr_addr(cur, 1, new), &lptr, 1);
3088	xfs_btree_copy_ptrs(cur,
3089		xfs_btree_ptr_addr(cur, 2, new), &rptr, 1);
3090	xfs_btree_log_ptrs(cur, nbp, 1, 2);
3091
3092	/* Fix up the cursor. */
3093	xfs_btree_setbuf(cur, cur->bc_nlevels, nbp);
3094	cur->bc_ptrs[cur->bc_nlevels] = nptr;
3095	cur->bc_nlevels++;
3096	*stat = 1;
3097	return 0;
3098error0:
3099	return error;
3100out0:
3101	*stat = 0;
3102	return 0;
3103}
3104
3105STATIC int
3106xfs_btree_make_block_unfull(
3107	struct xfs_btree_cur	*cur,	/* btree cursor */
3108	int			level,	/* btree level */
3109	int			numrecs,/* # of recs in block */
3110	int			*oindex,/* old tree index */
3111	int			*index,	/* new tree index */
3112	union xfs_btree_ptr	*nptr,	/* new btree ptr */
3113	struct xfs_btree_cur	**ncur,	/* new btree cursor */
3114	union xfs_btree_key	*key,	/* key of new block */
3115	int			*stat)
3116{
3117	int			error = 0;
3118
3119	if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3120	    level == cur->bc_nlevels - 1) {
3121		struct xfs_inode *ip = cur->bc_ino.ip;
3122
3123		if (numrecs < cur->bc_ops->get_dmaxrecs(cur, level)) {
3124			/* A root block that can be made bigger. */
3125			xfs_iroot_realloc(ip, 1, cur->bc_ino.whichfork);
3126			*stat = 1;
3127		} else {
3128			/* A root block that needs replacing */
3129			int	logflags = 0;
3130
3131			error = xfs_btree_new_iroot(cur, &logflags, stat);
3132			if (error || *stat == 0)
3133				return error;
3134
3135			xfs_trans_log_inode(cur->bc_tp, ip, logflags);
3136		}
3137
3138		return 0;
3139	}
3140
3141	/* First, try shifting an entry to the right neighbor. */
3142	error = xfs_btree_rshift(cur, level, stat);
3143	if (error || *stat)
3144		return error;
3145
3146	/* Next, try shifting an entry to the left neighbor. */
3147	error = xfs_btree_lshift(cur, level, stat);
3148	if (error)
3149		return error;
3150
3151	if (*stat) {
3152		*oindex = *index = cur->bc_ptrs[level];
3153		return 0;
3154	}
3155
3156	/*
3157	 * Next, try splitting the current block in half.
3158	 *
3159	 * If this works we have to re-set our variables because we
3160	 * could be in a different block now.
3161	 */
3162	error = xfs_btree_split(cur, level, nptr, key, ncur, stat);
3163	if (error || *stat == 0)
3164		return error;
3165
3166
3167	*index = cur->bc_ptrs[level];
3168	return 0;
3169}
3170
3171/*
3172 * Insert one record/level.  Return information to the caller
3173 * allowing the next level up to proceed if necessary.
3174 */
3175STATIC int
3176xfs_btree_insrec(
3177	struct xfs_btree_cur	*cur,	/* btree cursor */
3178	int			level,	/* level to insert record at */
3179	union xfs_btree_ptr	*ptrp,	/* i/o: block number inserted */
3180	union xfs_btree_rec	*rec,	/* record to insert */
3181	union xfs_btree_key	*key,	/* i/o: block key for ptrp */
3182	struct xfs_btree_cur	**curp,	/* output: new cursor replacing cur */
3183	int			*stat)	/* success/failure */
3184{
3185	struct xfs_btree_block	*block;	/* btree block */
3186	struct xfs_buf		*bp;	/* buffer for block */
3187	union xfs_btree_ptr	nptr;	/* new block ptr */
3188	struct xfs_btree_cur	*ncur;	/* new btree cursor */
3189	union xfs_btree_key	nkey;	/* new block key */
3190	union xfs_btree_key	*lkey;
3191	int			optr;	/* old key/record index */
3192	int			ptr;	/* key/record index */
3193	int			numrecs;/* number of records */
3194	int			error;	/* error return value */
3195	int			i;
3196	xfs_daddr_t		old_bn;
3197
3198	ncur = NULL;
3199	lkey = &nkey;
3200
3201	/*
3202	 * If we have an external root pointer, and we've made it to the
3203	 * root level, allocate a new root block and we're done.
3204	 */
3205	if (!(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) &&
3206	    (level >= cur->bc_nlevels)) {
3207		error = xfs_btree_new_root(cur, stat);
3208		xfs_btree_set_ptr_null(cur, ptrp);
3209
3210		return error;
3211	}
3212
3213	/* If we're off the left edge, return failure. */
3214	ptr = cur->bc_ptrs[level];
3215	if (ptr == 0) {
3216		*stat = 0;
3217		return 0;
3218	}
3219
3220	optr = ptr;
3221
3222	XFS_BTREE_STATS_INC(cur, insrec);
3223
3224	/* Get pointers to the btree buffer and block. */
3225	block = xfs_btree_get_block(cur, level, &bp);
3226	old_bn = bp ? bp->b_bn : XFS_BUF_DADDR_NULL;
3227	numrecs = xfs_btree_get_numrecs(block);
3228
3229#ifdef DEBUG
3230	error = xfs_btree_check_block(cur, block, level, bp);
3231	if (error)
3232		goto error0;
3233
3234	/* Check that the new entry is being inserted in the right place. */
3235	if (ptr <= numrecs) {
3236		if (level == 0) {
3237			ASSERT(cur->bc_ops->recs_inorder(cur, rec,
3238				xfs_btree_rec_addr(cur, ptr, block)));
3239		} else {
3240			ASSERT(cur->bc_ops->keys_inorder(cur, key,
3241				xfs_btree_key_addr(cur, ptr, block)));
3242		}
3243	}
3244#endif
3245
3246	/*
3247	 * If the block is full, we can't insert the new entry until we
3248	 * make the block un-full.
3249	 */
3250	xfs_btree_set_ptr_null(cur, &nptr);
3251	if (numrecs == cur->bc_ops->get_maxrecs(cur, level)) {
3252		error = xfs_btree_make_block_unfull(cur, level, numrecs,
3253					&optr, &ptr, &nptr, &ncur, lkey, stat);
3254		if (error || *stat == 0)
3255			goto error0;
3256	}
3257
3258	/*
3259	 * The current block may have changed if the block was
3260	 * previously full and we have just made space in it.
3261	 */
3262	block = xfs_btree_get_block(cur, level, &bp);
3263	numrecs = xfs_btree_get_numrecs(block);
3264
3265#ifdef DEBUG
3266	error = xfs_btree_check_block(cur, block, level, bp);
3267	if (error)
3268		return error;
3269#endif
3270
3271	/*
3272	 * At this point we know there's room for our new entry in the block
3273	 * we're pointing at.
3274	 */
3275	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr + 1);
3276
3277	if (level > 0) {
3278		/* It's a nonleaf. make a hole in the keys and ptrs */
3279		union xfs_btree_key	*kp;
3280		union xfs_btree_ptr	*pp;
3281
3282		kp = xfs_btree_key_addr(cur, ptr, block);
3283		pp = xfs_btree_ptr_addr(cur, ptr, block);
3284
3285		for (i = numrecs - ptr; i >= 0; i--) {
3286			error = xfs_btree_debug_check_ptr(cur, pp, i, level);
3287			if (error)
3288				return error;
3289		}
3290
3291		xfs_btree_shift_keys(cur, kp, 1, numrecs - ptr + 1);
3292		xfs_btree_shift_ptrs(cur, pp, 1, numrecs - ptr + 1);
3293
3294		error = xfs_btree_debug_check_ptr(cur, ptrp, 0, level);
3295		if (error)
3296			goto error0;
3297
3298		/* Now put the new data in, bump numrecs and log it. */
3299		xfs_btree_copy_keys(cur, kp, key, 1);
3300		xfs_btree_copy_ptrs(cur, pp, ptrp, 1);
3301		numrecs++;
3302		xfs_btree_set_numrecs(block, numrecs);
3303		xfs_btree_log_ptrs(cur, bp, ptr, numrecs);
3304		xfs_btree_log_keys(cur, bp, ptr, numrecs);
3305#ifdef DEBUG
3306		if (ptr < numrecs) {
3307			ASSERT(cur->bc_ops->keys_inorder(cur, kp,
3308				xfs_btree_key_addr(cur, ptr + 1, block)));
3309		}
3310#endif
3311	} else {
3312		/* It's a leaf. make a hole in the records */
3313		union xfs_btree_rec             *rp;
3314
3315		rp = xfs_btree_rec_addr(cur, ptr, block);
3316
3317		xfs_btree_shift_recs(cur, rp, 1, numrecs - ptr + 1);
3318
3319		/* Now put the new data in, bump numrecs and log it. */
3320		xfs_btree_copy_recs(cur, rp, rec, 1);
3321		xfs_btree_set_numrecs(block, ++numrecs);
3322		xfs_btree_log_recs(cur, bp, ptr, numrecs);
3323#ifdef DEBUG
3324		if (ptr < numrecs) {
3325			ASSERT(cur->bc_ops->recs_inorder(cur, rp,
3326				xfs_btree_rec_addr(cur, ptr + 1, block)));
3327		}
3328#endif
3329	}
3330
3331	/* Log the new number of records in the btree header. */
3332	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3333
3334	/*
3335	 * If we just inserted into a new tree block, we have to
3336	 * recalculate nkey here because nkey is out of date.
3337	 *
3338	 * Otherwise we're just updating an existing block (having shoved
3339	 * some records into the new tree block), so use the regular key
3340	 * update mechanism.
3341	 */
3342	if (bp && bp->b_bn != old_bn) {
3343		xfs_btree_get_keys(cur, block, lkey);
3344	} else if (xfs_btree_needs_key_update(cur, optr)) {
3345		error = xfs_btree_update_keys(cur, level);
3346		if (error)
3347			goto error0;
3348	}
3349
3350	/*
3351	 * If we are tracking the last record in the tree and
3352	 * we are at the far right edge of the tree, update it.
3353	 */
3354	if (xfs_btree_is_lastrec(cur, block, level)) {
3355		cur->bc_ops->update_lastrec(cur, block, rec,
3356					    ptr, LASTREC_INSREC);
3357	}
3358
3359	/*
3360	 * Return the new block number, if any.
3361	 * If there is one, give back a record value and a cursor too.
3362	 */
3363	*ptrp = nptr;
3364	if (!xfs_btree_ptr_is_null(cur, &nptr)) {
3365		xfs_btree_copy_keys(cur, key, lkey, 1);
3366		*curp = ncur;
3367	}
3368
3369	*stat = 1;
3370	return 0;
3371
3372error0:
3373	return error;
3374}
3375
3376/*
3377 * Insert the record at the point referenced by cur.
3378 *
3379 * A multi-level split of the tree on insert will invalidate the original
3380 * cursor.  All callers of this function should assume that the cursor is
3381 * no longer valid and revalidate it.
3382 */
3383int
3384xfs_btree_insert(
3385	struct xfs_btree_cur	*cur,
3386	int			*stat)
3387{
3388	int			error;	/* error return value */
3389	int			i;	/* result value, 0 for failure */
3390	int			level;	/* current level number in btree */
3391	union xfs_btree_ptr	nptr;	/* new block number (split result) */
3392	struct xfs_btree_cur	*ncur;	/* new cursor (split result) */
3393	struct xfs_btree_cur	*pcur;	/* previous level's cursor */
3394	union xfs_btree_key	bkey;	/* key of block to insert */
3395	union xfs_btree_key	*key;
3396	union xfs_btree_rec	rec;	/* record to insert */
3397
3398	level = 0;
3399	ncur = NULL;
3400	pcur = cur;
3401	key = &bkey;
3402
3403	xfs_btree_set_ptr_null(cur, &nptr);
3404
3405	/* Make a key out of the record data to be inserted, and save it. */
3406	cur->bc_ops->init_rec_from_cur(cur, &rec);
3407	cur->bc_ops->init_key_from_rec(key, &rec);
3408
3409	/*
3410	 * Loop going up the tree, starting at the leaf level.
3411	 * Stop when we don't get a split block, that must mean that
3412	 * the insert is finished with this level.
3413	 */
3414	do {
3415		/*
3416		 * Insert nrec/nptr into this level of the tree.
3417		 * Note if we fail, nptr will be null.
3418		 */
3419		error = xfs_btree_insrec(pcur, level, &nptr, &rec, key,
3420				&ncur, &i);
3421		if (error) {
3422			if (pcur != cur)
3423				xfs_btree_del_cursor(pcur, XFS_BTREE_ERROR);
3424			goto error0;
3425		}
3426
3427		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3428			error = -EFSCORRUPTED;
3429			goto error0;
3430		}
3431		level++;
3432
3433		/*
3434		 * See if the cursor we just used is trash.
3435		 * Can't trash the caller's cursor, but otherwise we should
3436		 * if ncur is a new cursor or we're about to be done.
3437		 */
3438		if (pcur != cur &&
3439		    (ncur || xfs_btree_ptr_is_null(cur, &nptr))) {
3440			/* Save the state from the cursor before we trash it */
3441			if (cur->bc_ops->update_cursor)
3442				cur->bc_ops->update_cursor(pcur, cur);
3443			cur->bc_nlevels = pcur->bc_nlevels;
3444			xfs_btree_del_cursor(pcur, XFS_BTREE_NOERROR);
3445		}
3446		/* If we got a new cursor, switch to it. */
3447		if (ncur) {
3448			pcur = ncur;
3449			ncur = NULL;
3450		}
3451	} while (!xfs_btree_ptr_is_null(cur, &nptr));
3452
3453	*stat = i;
3454	return 0;
3455error0:
3456	return error;
3457}
3458
3459/*
3460 * Try to merge a non-leaf block back into the inode root.
3461 *
3462 * Note: the killroot names comes from the fact that we're effectively
3463 * killing the old root block.  But because we can't just delete the
3464 * inode we have to copy the single block it was pointing to into the
3465 * inode.
3466 */
3467STATIC int
3468xfs_btree_kill_iroot(
3469	struct xfs_btree_cur	*cur)
3470{
3471	int			whichfork = cur->bc_ino.whichfork;
3472	struct xfs_inode	*ip = cur->bc_ino.ip;
3473	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, whichfork);
3474	struct xfs_btree_block	*block;
3475	struct xfs_btree_block	*cblock;
3476	union xfs_btree_key	*kp;
3477	union xfs_btree_key	*ckp;
3478	union xfs_btree_ptr	*pp;
3479	union xfs_btree_ptr	*cpp;
3480	struct xfs_buf		*cbp;
3481	int			level;
3482	int			index;
3483	int			numrecs;
3484	int			error;
3485#ifdef DEBUG
3486	union xfs_btree_ptr	ptr;
3487#endif
3488	int			i;
3489
3490	ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
3491	ASSERT(cur->bc_nlevels > 1);
3492
3493	/*
3494	 * Don't deal with the root block needs to be a leaf case.
3495	 * We're just going to turn the thing back into extents anyway.
3496	 */
3497	level = cur->bc_nlevels - 1;
3498	if (level == 1)
3499		goto out0;
3500
3501	/*
3502	 * Give up if the root has multiple children.
3503	 */
3504	block = xfs_btree_get_iroot(cur);
3505	if (xfs_btree_get_numrecs(block) != 1)
3506		goto out0;
3507
3508	cblock = xfs_btree_get_block(cur, level - 1, &cbp);
3509	numrecs = xfs_btree_get_numrecs(cblock);
3510
3511	/*
3512	 * Only do this if the next level will fit.
3513	 * Then the data must be copied up to the inode,
3514	 * instead of freeing the root you free the next level.
3515	 */
3516	if (numrecs > cur->bc_ops->get_dmaxrecs(cur, level))
3517		goto out0;
3518
3519	XFS_BTREE_STATS_INC(cur, killroot);
3520
3521#ifdef DEBUG
3522	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_LEFTSIB);
3523	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3524	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
3525	ASSERT(xfs_btree_ptr_is_null(cur, &ptr));
3526#endif
3527
3528	index = numrecs - cur->bc_ops->get_maxrecs(cur, level);
3529	if (index) {
3530		xfs_iroot_realloc(cur->bc_ino.ip, index,
3531				  cur->bc_ino.whichfork);
3532		block = ifp->if_broot;
3533	}
3534
3535	be16_add_cpu(&block->bb_numrecs, index);
3536	ASSERT(block->bb_numrecs == cblock->bb_numrecs);
3537
3538	kp = xfs_btree_key_addr(cur, 1, block);
3539	ckp = xfs_btree_key_addr(cur, 1, cblock);
3540	xfs_btree_copy_keys(cur, kp, ckp, numrecs);
3541
3542	pp = xfs_btree_ptr_addr(cur, 1, block);
3543	cpp = xfs_btree_ptr_addr(cur, 1, cblock);
3544
3545	for (i = 0; i < numrecs; i++) {
3546		error = xfs_btree_debug_check_ptr(cur, cpp, i, level - 1);
3547		if (error)
3548			return error;
3549	}
3550
3551	xfs_btree_copy_ptrs(cur, pp, cpp, numrecs);
3552
3553	error = xfs_btree_free_block(cur, cbp);
3554	if (error)
3555		return error;
3556
3557	cur->bc_bufs[level - 1] = NULL;
3558	be16_add_cpu(&block->bb_level, -1);
3559	xfs_trans_log_inode(cur->bc_tp, ip,
3560		XFS_ILOG_CORE | xfs_ilog_fbroot(cur->bc_ino.whichfork));
3561	cur->bc_nlevels--;
3562out0:
3563	return 0;
3564}
3565
3566/*
3567 * Kill the current root node, and replace it with it's only child node.
3568 */
3569STATIC int
3570xfs_btree_kill_root(
3571	struct xfs_btree_cur	*cur,
3572	struct xfs_buf		*bp,
3573	int			level,
3574	union xfs_btree_ptr	*newroot)
3575{
3576	int			error;
3577
3578	XFS_BTREE_STATS_INC(cur, killroot);
3579
3580	/*
3581	 * Update the root pointer, decreasing the level by 1 and then
3582	 * free the old root.
3583	 */
3584	cur->bc_ops->set_root(cur, newroot, -1);
3585
3586	error = xfs_btree_free_block(cur, bp);
3587	if (error)
3588		return error;
3589
3590	cur->bc_bufs[level] = NULL;
3591	cur->bc_ra[level] = 0;
3592	cur->bc_nlevels--;
3593
3594	return 0;
3595}
3596
3597STATIC int
3598xfs_btree_dec_cursor(
3599	struct xfs_btree_cur	*cur,
3600	int			level,
3601	int			*stat)
3602{
3603	int			error;
3604	int			i;
3605
3606	if (level > 0) {
3607		error = xfs_btree_decrement(cur, level, &i);
3608		if (error)
3609			return error;
3610	}
3611
3612	*stat = 1;
3613	return 0;
3614}
3615
3616/*
3617 * Single level of the btree record deletion routine.
3618 * Delete record pointed to by cur/level.
3619 * Remove the record from its block then rebalance the tree.
3620 * Return 0 for error, 1 for done, 2 to go on to the next level.
3621 */
3622STATIC int					/* error */
3623xfs_btree_delrec(
3624	struct xfs_btree_cur	*cur,		/* btree cursor */
3625	int			level,		/* level removing record from */
3626	int			*stat)		/* fail/done/go-on */
3627{
3628	struct xfs_btree_block	*block;		/* btree block */
3629	union xfs_btree_ptr	cptr;		/* current block ptr */
3630	struct xfs_buf		*bp;		/* buffer for block */
3631	int			error;		/* error return value */
3632	int			i;		/* loop counter */
3633	union xfs_btree_ptr	lptr;		/* left sibling block ptr */
3634	struct xfs_buf		*lbp;		/* left buffer pointer */
3635	struct xfs_btree_block	*left;		/* left btree block */
3636	int			lrecs = 0;	/* left record count */
3637	int			ptr;		/* key/record index */
3638	union xfs_btree_ptr	rptr;		/* right sibling block ptr */
3639	struct xfs_buf		*rbp;		/* right buffer pointer */
3640	struct xfs_btree_block	*right;		/* right btree block */
3641	struct xfs_btree_block	*rrblock;	/* right-right btree block */
3642	struct xfs_buf		*rrbp;		/* right-right buffer pointer */
3643	int			rrecs = 0;	/* right record count */
3644	struct xfs_btree_cur	*tcur;		/* temporary btree cursor */
3645	int			numrecs;	/* temporary numrec count */
3646
3647	tcur = NULL;
3648
3649	/* Get the index of the entry being deleted, check for nothing there. */
3650	ptr = cur->bc_ptrs[level];
3651	if (ptr == 0) {
3652		*stat = 0;
3653		return 0;
3654	}
3655
3656	/* Get the buffer & block containing the record or key/ptr. */
3657	block = xfs_btree_get_block(cur, level, &bp);
3658	numrecs = xfs_btree_get_numrecs(block);
3659
3660#ifdef DEBUG
3661	error = xfs_btree_check_block(cur, block, level, bp);
3662	if (error)
3663		goto error0;
3664#endif
3665
3666	/* Fail if we're off the end of the block. */
3667	if (ptr > numrecs) {
3668		*stat = 0;
3669		return 0;
3670	}
3671
3672	XFS_BTREE_STATS_INC(cur, delrec);
3673	XFS_BTREE_STATS_ADD(cur, moves, numrecs - ptr);
3674
3675	/* Excise the entries being deleted. */
3676	if (level > 0) {
3677		/* It's a nonleaf. operate on keys and ptrs */
3678		union xfs_btree_key	*lkp;
3679		union xfs_btree_ptr	*lpp;
3680
3681		lkp = xfs_btree_key_addr(cur, ptr + 1, block);
3682		lpp = xfs_btree_ptr_addr(cur, ptr + 1, block);
3683
3684		for (i = 0; i < numrecs - ptr; i++) {
3685			error = xfs_btree_debug_check_ptr(cur, lpp, i, level);
3686			if (error)
3687				goto error0;
3688		}
3689
3690		if (ptr < numrecs) {
3691			xfs_btree_shift_keys(cur, lkp, -1, numrecs - ptr);
3692			xfs_btree_shift_ptrs(cur, lpp, -1, numrecs - ptr);
3693			xfs_btree_log_keys(cur, bp, ptr, numrecs - 1);
3694			xfs_btree_log_ptrs(cur, bp, ptr, numrecs - 1);
3695		}
3696	} else {
3697		/* It's a leaf. operate on records */
3698		if (ptr < numrecs) {
3699			xfs_btree_shift_recs(cur,
3700				xfs_btree_rec_addr(cur, ptr + 1, block),
3701				-1, numrecs - ptr);
3702			xfs_btree_log_recs(cur, bp, ptr, numrecs - 1);
3703		}
3704	}
3705
3706	/*
3707	 * Decrement and log the number of entries in the block.
3708	 */
3709	xfs_btree_set_numrecs(block, --numrecs);
3710	xfs_btree_log_block(cur, bp, XFS_BB_NUMRECS);
3711
3712	/*
3713	 * If we are tracking the last record in the tree and
3714	 * we are at the far right edge of the tree, update it.
3715	 */
3716	if (xfs_btree_is_lastrec(cur, block, level)) {
3717		cur->bc_ops->update_lastrec(cur, block, NULL,
3718					    ptr, LASTREC_DELREC);
3719	}
3720
3721	/*
3722	 * We're at the root level.  First, shrink the root block in-memory.
3723	 * Try to get rid of the next level down.  If we can't then there's
3724	 * nothing left to do.
3725	 */
3726	if (level == cur->bc_nlevels - 1) {
3727		if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3728			xfs_iroot_realloc(cur->bc_ino.ip, -1,
3729					  cur->bc_ino.whichfork);
3730
3731			error = xfs_btree_kill_iroot(cur);
3732			if (error)
3733				goto error0;
3734
3735			error = xfs_btree_dec_cursor(cur, level, stat);
3736			if (error)
3737				goto error0;
3738			*stat = 1;
3739			return 0;
3740		}
3741
3742		/*
3743		 * If this is the root level, and there's only one entry left,
3744		 * and it's NOT the leaf level, then we can get rid of this
3745		 * level.
3746		 */
3747		if (numrecs == 1 && level > 0) {
3748			union xfs_btree_ptr	*pp;
3749			/*
3750			 * pp is still set to the first pointer in the block.
3751			 * Make it the new root of the btree.
3752			 */
3753			pp = xfs_btree_ptr_addr(cur, 1, block);
3754			error = xfs_btree_kill_root(cur, bp, level, pp);
3755			if (error)
3756				goto error0;
3757		} else if (level > 0) {
3758			error = xfs_btree_dec_cursor(cur, level, stat);
3759			if (error)
3760				goto error0;
3761		}
3762		*stat = 1;
3763		return 0;
3764	}
3765
3766	/*
3767	 * If we deleted the leftmost entry in the block, update the
3768	 * key values above us in the tree.
3769	 */
3770	if (xfs_btree_needs_key_update(cur, ptr)) {
3771		error = xfs_btree_update_keys(cur, level);
3772		if (error)
3773			goto error0;
3774	}
3775
3776	/*
3777	 * If the number of records remaining in the block is at least
3778	 * the minimum, we're done.
3779	 */
3780	if (numrecs >= cur->bc_ops->get_minrecs(cur, level)) {
3781		error = xfs_btree_dec_cursor(cur, level, stat);
3782		if (error)
3783			goto error0;
3784		return 0;
3785	}
3786
3787	/*
3788	 * Otherwise, we have to move some records around to keep the
3789	 * tree balanced.  Look at the left and right sibling blocks to
3790	 * see if we can re-balance by moving only one record.
3791	 */
3792	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
3793	xfs_btree_get_sibling(cur, block, &lptr, XFS_BB_LEFTSIB);
3794
3795	if (cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) {
3796		/*
3797		 * One child of root, need to get a chance to copy its contents
3798		 * into the root and delete it. Can't go up to next level,
3799		 * there's nothing to delete there.
3800		 */
3801		if (xfs_btree_ptr_is_null(cur, &rptr) &&
3802		    xfs_btree_ptr_is_null(cur, &lptr) &&
3803		    level == cur->bc_nlevels - 2) {
3804			error = xfs_btree_kill_iroot(cur);
3805			if (!error)
3806				error = xfs_btree_dec_cursor(cur, level, stat);
3807			if (error)
3808				goto error0;
3809			return 0;
3810		}
3811	}
3812
3813	ASSERT(!xfs_btree_ptr_is_null(cur, &rptr) ||
3814	       !xfs_btree_ptr_is_null(cur, &lptr));
3815
3816	/*
3817	 * Duplicate the cursor so our btree manipulations here won't
3818	 * disrupt the next level up.
3819	 */
3820	error = xfs_btree_dup_cursor(cur, &tcur);
3821	if (error)
3822		goto error0;
3823
3824	/*
3825	 * If there's a right sibling, see if it's ok to shift an entry
3826	 * out of it.
3827	 */
3828	if (!xfs_btree_ptr_is_null(cur, &rptr)) {
3829		/*
3830		 * Move the temp cursor to the last entry in the next block.
3831		 * Actually any entry but the first would suffice.
3832		 */
3833		i = xfs_btree_lastrec(tcur, level);
3834		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3835			error = -EFSCORRUPTED;
3836			goto error0;
3837		}
3838
3839		error = xfs_btree_increment(tcur, level, &i);
3840		if (error)
3841			goto error0;
3842		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3843			error = -EFSCORRUPTED;
3844			goto error0;
3845		}
3846
3847		i = xfs_btree_lastrec(tcur, level);
3848		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3849			error = -EFSCORRUPTED;
3850			goto error0;
3851		}
3852
3853		/* Grab a pointer to the block. */
3854		right = xfs_btree_get_block(tcur, level, &rbp);
3855#ifdef DEBUG
3856		error = xfs_btree_check_block(tcur, right, level, rbp);
3857		if (error)
3858			goto error0;
3859#endif
3860		/* Grab the current block number, for future use. */
3861		xfs_btree_get_sibling(tcur, right, &cptr, XFS_BB_LEFTSIB);
3862
3863		/*
3864		 * If right block is full enough so that removing one entry
3865		 * won't make it too empty, and left-shifting an entry out
3866		 * of right to us works, we're done.
3867		 */
3868		if (xfs_btree_get_numrecs(right) - 1 >=
3869		    cur->bc_ops->get_minrecs(tcur, level)) {
3870			error = xfs_btree_lshift(tcur, level, &i);
3871			if (error)
3872				goto error0;
3873			if (i) {
3874				ASSERT(xfs_btree_get_numrecs(block) >=
3875				       cur->bc_ops->get_minrecs(tcur, level));
3876
3877				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3878				tcur = NULL;
3879
3880				error = xfs_btree_dec_cursor(cur, level, stat);
3881				if (error)
3882					goto error0;
3883				return 0;
3884			}
3885		}
3886
3887		/*
3888		 * Otherwise, grab the number of records in right for
3889		 * future reference, and fix up the temp cursor to point
3890		 * to our block again (last record).
3891		 */
3892		rrecs = xfs_btree_get_numrecs(right);
3893		if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3894			i = xfs_btree_firstrec(tcur, level);
3895			if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3896				error = -EFSCORRUPTED;
3897				goto error0;
3898			}
3899
3900			error = xfs_btree_decrement(tcur, level, &i);
3901			if (error)
3902				goto error0;
3903			if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3904				error = -EFSCORRUPTED;
3905				goto error0;
3906			}
3907		}
3908	}
3909
3910	/*
3911	 * If there's a left sibling, see if it's ok to shift an entry
3912	 * out of it.
3913	 */
3914	if (!xfs_btree_ptr_is_null(cur, &lptr)) {
3915		/*
3916		 * Move the temp cursor to the first entry in the
3917		 * previous block.
3918		 */
3919		i = xfs_btree_firstrec(tcur, level);
3920		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3921			error = -EFSCORRUPTED;
3922			goto error0;
3923		}
3924
3925		error = xfs_btree_decrement(tcur, level, &i);
3926		if (error)
3927			goto error0;
3928		i = xfs_btree_firstrec(tcur, level);
3929		if (XFS_IS_CORRUPT(cur->bc_mp, i != 1)) {
3930			error = -EFSCORRUPTED;
3931			goto error0;
3932		}
3933
3934		/* Grab a pointer to the block. */
3935		left = xfs_btree_get_block(tcur, level, &lbp);
3936#ifdef DEBUG
3937		error = xfs_btree_check_block(cur, left, level, lbp);
3938		if (error)
3939			goto error0;
3940#endif
3941		/* Grab the current block number, for future use. */
3942		xfs_btree_get_sibling(tcur, left, &cptr, XFS_BB_RIGHTSIB);
3943
3944		/*
3945		 * If left block is full enough so that removing one entry
3946		 * won't make it too empty, and right-shifting an entry out
3947		 * of left to us works, we're done.
3948		 */
3949		if (xfs_btree_get_numrecs(left) - 1 >=
3950		    cur->bc_ops->get_minrecs(tcur, level)) {
3951			error = xfs_btree_rshift(tcur, level, &i);
3952			if (error)
3953				goto error0;
3954			if (i) {
3955				ASSERT(xfs_btree_get_numrecs(block) >=
3956				       cur->bc_ops->get_minrecs(tcur, level));
3957				xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3958				tcur = NULL;
3959				if (level == 0)
3960					cur->bc_ptrs[0]++;
3961
3962				*stat = 1;
3963				return 0;
3964			}
3965		}
3966
3967		/*
3968		 * Otherwise, grab the number of records in right for
3969		 * future reference.
3970		 */
3971		lrecs = xfs_btree_get_numrecs(left);
3972	}
3973
3974	/* Delete the temp cursor, we're done with it. */
3975	xfs_btree_del_cursor(tcur, XFS_BTREE_NOERROR);
3976	tcur = NULL;
3977
3978	/* If here, we need to do a join to keep the tree balanced. */
3979	ASSERT(!xfs_btree_ptr_is_null(cur, &cptr));
3980
3981	if (!xfs_btree_ptr_is_null(cur, &lptr) &&
3982	    lrecs + xfs_btree_get_numrecs(block) <=
3983			cur->bc_ops->get_maxrecs(cur, level)) {
3984		/*
3985		 * Set "right" to be the starting block,
3986		 * "left" to be the left neighbor.
3987		 */
3988		rptr = cptr;
3989		right = block;
3990		rbp = bp;
3991		error = xfs_btree_read_buf_block(cur, &lptr, 0, &left, &lbp);
3992		if (error)
3993			goto error0;
3994
3995	/*
3996	 * If that won't work, see if we can join with the right neighbor block.
3997	 */
3998	} else if (!xfs_btree_ptr_is_null(cur, &rptr) &&
3999		   rrecs + xfs_btree_get_numrecs(block) <=
4000			cur->bc_ops->get_maxrecs(cur, level)) {
4001		/*
4002		 * Set "left" to be the starting block,
4003		 * "right" to be the right neighbor.
4004		 */
4005		lptr = cptr;
4006		left = block;
4007		lbp = bp;
4008		error = xfs_btree_read_buf_block(cur, &rptr, 0, &right, &rbp);
4009		if (error)
4010			goto error0;
4011
4012	/*
4013	 * Otherwise, we can't fix the imbalance.
4014	 * Just return.  This is probably a logic error, but it's not fatal.
4015	 */
4016	} else {
4017		error = xfs_btree_dec_cursor(cur, level, stat);
4018		if (error)
4019			goto error0;
4020		return 0;
4021	}
4022
4023	rrecs = xfs_btree_get_numrecs(right);
4024	lrecs = xfs_btree_get_numrecs(left);
4025
4026	/*
4027	 * We're now going to join "left" and "right" by moving all the stuff
4028	 * in "right" to "left" and deleting "right".
4029	 */
4030	XFS_BTREE_STATS_ADD(cur, moves, rrecs);
4031	if (level > 0) {
4032		/* It's a non-leaf.  Move keys and pointers. */
4033		union xfs_btree_key	*lkp;	/* left btree key */
4034		union xfs_btree_ptr	*lpp;	/* left address pointer */
4035		union xfs_btree_key	*rkp;	/* right btree key */
4036		union xfs_btree_ptr	*rpp;	/* right address pointer */
4037
4038		lkp = xfs_btree_key_addr(cur, lrecs + 1, left);
4039		lpp = xfs_btree_ptr_addr(cur, lrecs + 1, left);
4040		rkp = xfs_btree_key_addr(cur, 1, right);
4041		rpp = xfs_btree_ptr_addr(cur, 1, right);
4042
4043		for (i = 1; i < rrecs; i++) {
4044			error = xfs_btree_debug_check_ptr(cur, rpp, i, level);
4045			if (error)
4046				goto error0;
4047		}
4048
4049		xfs_btree_copy_keys(cur, lkp, rkp, rrecs);
4050		xfs_btree_copy_ptrs(cur, lpp, rpp, rrecs);
4051
4052		xfs_btree_log_keys(cur, lbp, lrecs + 1, lrecs + rrecs);
4053		xfs_btree_log_ptrs(cur, lbp, lrecs + 1, lrecs + rrecs);
4054	} else {
4055		/* It's a leaf.  Move records.  */
4056		union xfs_btree_rec	*lrp;	/* left record pointer */
4057		union xfs_btree_rec	*rrp;	/* right record pointer */
4058
4059		lrp = xfs_btree_rec_addr(cur, lrecs + 1, left);
4060		rrp = xfs_btree_rec_addr(cur, 1, right);
4061
4062		xfs_btree_copy_recs(cur, lrp, rrp, rrecs);
4063		xfs_btree_log_recs(cur, lbp, lrecs + 1, lrecs + rrecs);
4064	}
4065
4066	XFS_BTREE_STATS_INC(cur, join);
4067
4068	/*
4069	 * Fix up the number of records and right block pointer in the
4070	 * surviving block, and log it.
4071	 */
4072	xfs_btree_set_numrecs(left, lrecs + rrecs);
4073	xfs_btree_get_sibling(cur, right, &cptr, XFS_BB_RIGHTSIB),
4074	xfs_btree_set_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4075	xfs_btree_log_block(cur, lbp, XFS_BB_NUMRECS | XFS_BB_RIGHTSIB);
4076
4077	/* If there is a right sibling, point it to the remaining block. */
4078	xfs_btree_get_sibling(cur, left, &cptr, XFS_BB_RIGHTSIB);
4079	if (!xfs_btree_ptr_is_null(cur, &cptr)) {
4080		error = xfs_btree_read_buf_block(cur, &cptr, 0, &rrblock, &rrbp);
4081		if (error)
4082			goto error0;
4083		xfs_btree_set_sibling(cur, rrblock, &lptr, XFS_BB_LEFTSIB);
4084		xfs_btree_log_block(cur, rrbp, XFS_BB_LEFTSIB);
4085	}
4086
4087	/* Free the deleted block. */
4088	error = xfs_btree_free_block(cur, rbp);
4089	if (error)
4090		goto error0;
4091
4092	/*
4093	 * If we joined with the left neighbor, set the buffer in the
4094	 * cursor to the left block, and fix up the index.
4095	 */
4096	if (bp != lbp) {
4097		cur->bc_bufs[level] = lbp;
4098		cur->bc_ptrs[level] += lrecs;
4099		cur->bc_ra[level] = 0;
4100	}
4101	/*
4102	 * If we joined with the right neighbor and there's a level above
4103	 * us, increment the cursor at that level.
4104	 */
4105	else if ((cur->bc_flags & XFS_BTREE_ROOT_IN_INODE) ||
4106		   (level + 1 < cur->bc_nlevels)) {
4107		error = xfs_btree_increment(cur, level + 1, &i);
4108		if (error)
4109			goto error0;
4110	}
4111
4112	/*
4113	 * Readjust the ptr at this level if it's not a leaf, since it's
4114	 * still pointing at the deletion point, which makes the cursor
4115	 * inconsistent.  If this makes the ptr 0, the caller fixes it up.
4116	 * We can't use decrement because it would change the next level up.
4117	 */
4118	if (level > 0)
4119		cur->bc_ptrs[level]--;
4120
4121	/*
4122	 * We combined blocks, so we have to update the parent keys if the
4123	 * btree supports overlapped intervals.  However, bc_ptrs[level + 1]
4124	 * points to the old block so that the caller knows which record to
4125	 * delete.  Therefore, the caller must be savvy enough to call updkeys
4126	 * for us if we return stat == 2.  The other exit points from this
4127	 * function don't require deletions further up the tree, so they can
4128	 * call updkeys directly.
4129	 */
4130
4131	/* Return value means the next level up has something to do. */
4132	*stat = 2;
4133	return 0;
4134
4135error0:
4136	if (tcur)
4137		xfs_btree_del_cursor(tcur, XFS_BTREE_ERROR);
4138	return error;
4139}
4140
4141/*
4142 * Delete the record pointed to by cur.
4143 * The cursor refers to the place where the record was (could be inserted)
4144 * when the operation returns.
4145 */
4146int					/* error */
4147xfs_btree_delete(
4148	struct xfs_btree_cur	*cur,
4149	int			*stat)	/* success/failure */
4150{
4151	int			error;	/* error return value */
4152	int			level;
4153	int			i;
4154	bool			joined = false;
4155
4156	/*
4157	 * Go up the tree, starting at leaf level.
4158	 *
4159	 * If 2 is returned then a join was done; go to the next level.
4160	 * Otherwise we are done.
4161	 */
4162	for (level = 0, i = 2; i == 2; level++) {
4163		error = xfs_btree_delrec(cur, level, &i);
4164		if (error)
4165			goto error0;
4166		if (i == 2)
4167			joined = true;
4168	}
4169
4170	/*
4171	 * If we combined blocks as part of deleting the record, delrec won't
4172	 * have updated the parent high keys so we have to do that here.
4173	 */
4174	if (joined && (cur->bc_flags & XFS_BTREE_OVERLAPPING)) {
4175		error = xfs_btree_updkeys_force(cur, 0);
4176		if (error)
4177			goto error0;
4178	}
4179
4180	if (i == 0) {
4181		for (level = 1; level < cur->bc_nlevels; level++) {
4182			if (cur->bc_ptrs[level] == 0) {
4183				error = xfs_btree_decrement(cur, level, &i);
4184				if (error)
4185					goto error0;
4186				break;
4187			}
4188		}
4189	}
4190
4191	*stat = i;
4192	return 0;
4193error0:
4194	return error;
4195}
4196
4197/*
4198 * Get the data from the pointed-to record.
4199 */
4200int					/* error */
4201xfs_btree_get_rec(
4202	struct xfs_btree_cur	*cur,	/* btree cursor */
4203	union xfs_btree_rec	**recp,	/* output: btree record */
4204	int			*stat)	/* output: success/failure */
4205{
4206	struct xfs_btree_block	*block;	/* btree block */
4207	struct xfs_buf		*bp;	/* buffer pointer */
4208	int			ptr;	/* record number */
4209#ifdef DEBUG
4210	int			error;	/* error return value */
4211#endif
4212
4213	ptr = cur->bc_ptrs[0];
4214	block = xfs_btree_get_block(cur, 0, &bp);
4215
4216#ifdef DEBUG
4217	error = xfs_btree_check_block(cur, block, 0, bp);
4218	if (error)
4219		return error;
4220#endif
4221
4222	/*
4223	 * Off the right end or left end, return failure.
4224	 */
4225	if (ptr > xfs_btree_get_numrecs(block) || ptr <= 0) {
4226		*stat = 0;
4227		return 0;
4228	}
4229
4230	/*
4231	 * Point to the record and extract its data.
4232	 */
4233	*recp = xfs_btree_rec_addr(cur, ptr, block);
4234	*stat = 1;
4235	return 0;
4236}
4237
4238/* Visit a block in a btree. */
4239STATIC int
4240xfs_btree_visit_block(
4241	struct xfs_btree_cur		*cur,
4242	int				level,
4243	xfs_btree_visit_blocks_fn	fn,
4244	void				*data)
4245{
4246	struct xfs_btree_block		*block;
4247	struct xfs_buf			*bp;
4248	union xfs_btree_ptr		rptr;
4249	int				error;
4250
4251	/* do right sibling readahead */
4252	xfs_btree_readahead(cur, level, XFS_BTCUR_RIGHTRA);
4253	block = xfs_btree_get_block(cur, level, &bp);
4254
4255	/* process the block */
4256	error = fn(cur, level, data);
4257	if (error)
4258		return error;
4259
4260	/* now read rh sibling block for next iteration */
4261	xfs_btree_get_sibling(cur, block, &rptr, XFS_BB_RIGHTSIB);
4262	if (xfs_btree_ptr_is_null(cur, &rptr))
4263		return -ENOENT;
4264
4265	return xfs_btree_lookup_get_block(cur, level, &rptr, &block);
4266}
4267
4268
4269/* Visit every block in a btree. */
4270int
4271xfs_btree_visit_blocks(
4272	struct xfs_btree_cur		*cur,
4273	xfs_btree_visit_blocks_fn	fn,
4274	unsigned int			flags,
4275	void				*data)
4276{
4277	union xfs_btree_ptr		lptr;
4278	int				level;
4279	struct xfs_btree_block		*block = NULL;
4280	int				error = 0;
4281
4282	cur->bc_ops->init_ptr_from_cur(cur, &lptr);
4283
4284	/* for each level */
4285	for (level = cur->bc_nlevels - 1; level >= 0; level--) {
4286		/* grab the left hand block */
4287		error = xfs_btree_lookup_get_block(cur, level, &lptr, &block);
4288		if (error)
4289			return error;
4290
4291		/* readahead the left most block for the next level down */
4292		if (level > 0) {
4293			union xfs_btree_ptr     *ptr;
4294
4295			ptr = xfs_btree_ptr_addr(cur, 1, block);
4296			xfs_btree_readahead_ptr(cur, ptr, 1);
4297
4298			/* save for the next iteration of the loop */
4299			xfs_btree_copy_ptrs(cur, &lptr, ptr, 1);
4300
4301			if (!(flags & XFS_BTREE_VISIT_LEAVES))
4302				continue;
4303		} else if (!(flags & XFS_BTREE_VISIT_RECORDS)) {
4304			continue;
4305		}
4306
4307		/* for each buffer in the level */
4308		do {
4309			error = xfs_btree_visit_block(cur, level, fn, data);
4310		} while (!error);
4311
4312		if (error != -ENOENT)
4313			return error;
4314	}
4315
4316	return 0;
4317}
4318
4319/*
4320 * Change the owner of a btree.
4321 *
4322 * The mechanism we use here is ordered buffer logging. Because we don't know
4323 * how many buffers were are going to need to modify, we don't really want to
4324 * have to make transaction reservations for the worst case of every buffer in a
4325 * full size btree as that may be more space that we can fit in the log....
4326 *
4327 * We do the btree walk in the most optimal manner possible - we have sibling
4328 * pointers so we can just walk all the blocks on each level from left to right
4329 * in a single pass, and then move to the next level and do the same. We can
4330 * also do readahead on the sibling pointers to get IO moving more quickly,
4331 * though for slow disks this is unlikely to make much difference to performance
4332 * as the amount of CPU work we have to do before moving to the next block is
4333 * relatively small.
4334 *
4335 * For each btree block that we load, modify the owner appropriately, set the
4336 * buffer as an ordered buffer and log it appropriately. We need to ensure that
4337 * we mark the region we change dirty so that if the buffer is relogged in
4338 * a subsequent transaction the changes we make here as an ordered buffer are
4339 * correctly relogged in that transaction.  If we are in recovery context, then
4340 * just queue the modified buffer as delayed write buffer so the transaction
4341 * recovery completion writes the changes to disk.
4342 */
4343struct xfs_btree_block_change_owner_info {
4344	uint64_t		new_owner;
4345	struct list_head	*buffer_list;
4346};
4347
4348static int
4349xfs_btree_block_change_owner(
4350	struct xfs_btree_cur	*cur,
4351	int			level,
4352	void			*data)
4353{
4354	struct xfs_btree_block_change_owner_info	*bbcoi = data;
4355	struct xfs_btree_block	*block;
4356	struct xfs_buf		*bp;
4357
4358	/* modify the owner */
4359	block = xfs_btree_get_block(cur, level, &bp);
4360	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
4361		if (block->bb_u.l.bb_owner == cpu_to_be64(bbcoi->new_owner))
4362			return 0;
4363		block->bb_u.l.bb_owner = cpu_to_be64(bbcoi->new_owner);
4364	} else {
4365		if (block->bb_u.s.bb_owner == cpu_to_be32(bbcoi->new_owner))
4366			return 0;
4367		block->bb_u.s.bb_owner = cpu_to_be32(bbcoi->new_owner);
4368	}
4369
4370	/*
4371	 * If the block is a root block hosted in an inode, we might not have a
4372	 * buffer pointer here and we shouldn't attempt to log the change as the
4373	 * information is already held in the inode and discarded when the root
4374	 * block is formatted into the on-disk inode fork. We still change it,
4375	 * though, so everything is consistent in memory.
4376	 */
4377	if (!bp) {
4378		ASSERT(cur->bc_flags & XFS_BTREE_ROOT_IN_INODE);
4379		ASSERT(level == cur->bc_nlevels - 1);
4380		return 0;
4381	}
4382
4383	if (cur->bc_tp) {
4384		if (!xfs_trans_ordered_buf(cur->bc_tp, bp)) {
4385			xfs_btree_log_block(cur, bp, XFS_BB_OWNER);
4386			return -EAGAIN;
4387		}
4388	} else {
4389		xfs_buf_delwri_queue(bp, bbcoi->buffer_list);
4390	}
4391
4392	return 0;
4393}
4394
4395int
4396xfs_btree_change_owner(
4397	struct xfs_btree_cur	*cur,
4398	uint64_t		new_owner,
4399	struct list_head	*buffer_list)
4400{
4401	struct xfs_btree_block_change_owner_info	bbcoi;
4402
4403	bbcoi.new_owner = new_owner;
4404	bbcoi.buffer_list = buffer_list;
4405
4406	return xfs_btree_visit_blocks(cur, xfs_btree_block_change_owner,
4407			XFS_BTREE_VISIT_ALL, &bbcoi);
4408}
4409
4410/* Verify the v5 fields of a long-format btree block. */
4411xfs_failaddr_t
4412xfs_btree_lblock_v5hdr_verify(
4413	struct xfs_buf		*bp,
4414	uint64_t		owner)
4415{
4416	struct xfs_mount	*mp = bp->b_mount;
4417	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4418
4419	if (!xfs_sb_version_hascrc(&mp->m_sb))
4420		return __this_address;
4421	if (!uuid_equal(&block->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid))
4422		return __this_address;
4423	if (block->bb_u.l.bb_blkno != cpu_to_be64(bp->b_bn))
4424		return __this_address;
4425	if (owner != XFS_RMAP_OWN_UNKNOWN &&
4426	    be64_to_cpu(block->bb_u.l.bb_owner) != owner)
4427		return __this_address;
4428	return NULL;
4429}
4430
4431/* Verify a long-format btree block. */
4432xfs_failaddr_t
4433xfs_btree_lblock_verify(
4434	struct xfs_buf		*bp,
4435	unsigned int		max_recs)
4436{
4437	struct xfs_mount	*mp = bp->b_mount;
4438	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4439
4440	/* numrecs verification */
4441	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4442		return __this_address;
4443
4444	/* sibling pointer verification */
4445	if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK) &&
4446	    !xfs_verify_fsbno(mp, be64_to_cpu(block->bb_u.l.bb_leftsib)))
4447		return __this_address;
4448	if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK) &&
4449	    !xfs_verify_fsbno(mp, be64_to_cpu(block->bb_u.l.bb_rightsib)))
4450		return __this_address;
4451
4452	return NULL;
4453}
4454
4455/**
4456 * xfs_btree_sblock_v5hdr_verify() -- verify the v5 fields of a short-format
4457 *				      btree block
4458 *
4459 * @bp: buffer containing the btree block
4460 */
4461xfs_failaddr_t
4462xfs_btree_sblock_v5hdr_verify(
4463	struct xfs_buf		*bp)
4464{
4465	struct xfs_mount	*mp = bp->b_mount;
4466	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4467	struct xfs_perag	*pag = bp->b_pag;
4468
4469	if (!xfs_sb_version_hascrc(&mp->m_sb))
4470		return __this_address;
4471	if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_meta_uuid))
4472		return __this_address;
4473	if (block->bb_u.s.bb_blkno != cpu_to_be64(bp->b_bn))
4474		return __this_address;
4475	if (pag && be32_to_cpu(block->bb_u.s.bb_owner) != pag->pag_agno)
4476		return __this_address;
4477	return NULL;
4478}
4479
4480/**
4481 * xfs_btree_sblock_verify() -- verify a short-format btree block
4482 *
4483 * @bp: buffer containing the btree block
4484 * @max_recs: maximum records allowed in this btree node
4485 */
4486xfs_failaddr_t
4487xfs_btree_sblock_verify(
4488	struct xfs_buf		*bp,
4489	unsigned int		max_recs)
4490{
4491	struct xfs_mount	*mp = bp->b_mount;
4492	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
4493	xfs_agblock_t		agno;
4494
4495	/* numrecs verification */
4496	if (be16_to_cpu(block->bb_numrecs) > max_recs)
4497		return __this_address;
4498
4499	/* sibling pointer verification */
4500	agno = xfs_daddr_to_agno(mp, XFS_BUF_ADDR(bp));
4501	if (block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK) &&
4502	    !xfs_verify_agbno(mp, agno, be32_to_cpu(block->bb_u.s.bb_leftsib)))
4503		return __this_address;
4504	if (block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK) &&
4505	    !xfs_verify_agbno(mp, agno, be32_to_cpu(block->bb_u.s.bb_rightsib)))
4506		return __this_address;
4507
4508	return NULL;
4509}
4510
4511/*
4512 * Calculate the number of btree levels needed to store a given number of
4513 * records in a short-format btree.
4514 */
4515uint
4516xfs_btree_compute_maxlevels(
4517	uint			*limits,
4518	unsigned long		len)
4519{
4520	uint			level;
4521	unsigned long		maxblocks;
4522
4523	maxblocks = (len + limits[0] - 1) / limits[0];
4524	for (level = 1; maxblocks > 1; level++)
4525		maxblocks = (maxblocks + limits[1] - 1) / limits[1];
4526	return level;
4527}
4528
4529/*
4530 * Query a regular btree for all records overlapping a given interval.
4531 * Start with a LE lookup of the key of low_rec and return all records
4532 * until we find a record with a key greater than the key of high_rec.
4533 */
4534STATIC int
4535xfs_btree_simple_query_range(
4536	struct xfs_btree_cur		*cur,
4537	union xfs_btree_key		*low_key,
4538	union xfs_btree_key		*high_key,
4539	xfs_btree_query_range_fn	fn,
4540	void				*priv)
4541{
4542	union xfs_btree_rec		*recp;
4543	union xfs_btree_key		rec_key;
4544	int64_t				diff;
4545	int				stat;
4546	bool				firstrec = true;
4547	int				error;
4548
4549	ASSERT(cur->bc_ops->init_high_key_from_rec);
4550	ASSERT(cur->bc_ops->diff_two_keys);
4551
4552	/*
4553	 * Find the leftmost record.  The btree cursor must be set
4554	 * to the low record used to generate low_key.
4555	 */
4556	stat = 0;
4557	error = xfs_btree_lookup(cur, XFS_LOOKUP_LE, &stat);
4558	if (error)
4559		goto out;
4560
4561	/* Nothing?  See if there's anything to the right. */
4562	if (!stat) {
4563		error = xfs_btree_increment(cur, 0, &stat);
4564		if (error)
4565			goto out;
4566	}
4567
4568	while (stat) {
4569		/* Find the record. */
4570		error = xfs_btree_get_rec(cur, &recp, &stat);
4571		if (error || !stat)
4572			break;
4573
4574		/* Skip if high_key(rec) < low_key. */
4575		if (firstrec) {
4576			cur->bc_ops->init_high_key_from_rec(&rec_key, recp);
4577			firstrec = false;
4578			diff = cur->bc_ops->diff_two_keys(cur, low_key,
4579					&rec_key);
4580			if (diff > 0)
4581				goto advloop;
4582		}
4583
4584		/* Stop if high_key < low_key(rec). */
4585		cur->bc_ops->init_key_from_rec(&rec_key, recp);
4586		diff = cur->bc_ops->diff_two_keys(cur, &rec_key, high_key);
4587		if (diff > 0)
4588			break;
4589
4590		/* Callback */
4591		error = fn(cur, recp, priv);
4592		if (error)
4593			break;
4594
4595advloop:
4596		/* Move on to the next record. */
4597		error = xfs_btree_increment(cur, 0, &stat);
4598		if (error)
4599			break;
4600	}
4601
4602out:
4603	return error;
4604}
4605
4606/*
4607 * Query an overlapped interval btree for all records overlapping a given
4608 * interval.  This function roughly follows the algorithm given in
4609 * "Interval Trees" of _Introduction to Algorithms_, which is section
4610 * 14.3 in the 2nd and 3rd editions.
4611 *
4612 * First, generate keys for the low and high records passed in.
4613 *
4614 * For any leaf node, generate the high and low keys for the record.
4615 * If the record keys overlap with the query low/high keys, pass the
4616 * record to the function iterator.
4617 *
4618 * For any internal node, compare the low and high keys of each
4619 * pointer against the query low/high keys.  If there's an overlap,
4620 * follow the pointer.
4621 *
4622 * As an optimization, we stop scanning a block when we find a low key
4623 * that is greater than the query's high key.
4624 */
4625STATIC int
4626xfs_btree_overlapped_query_range(
4627	struct xfs_btree_cur		*cur,
4628	union xfs_btree_key		*low_key,
4629	union xfs_btree_key		*high_key,
4630	xfs_btree_query_range_fn	fn,
4631	void				*priv)
4632{
4633	union xfs_btree_ptr		ptr;
4634	union xfs_btree_ptr		*pp;
4635	union xfs_btree_key		rec_key;
4636	union xfs_btree_key		rec_hkey;
4637	union xfs_btree_key		*lkp;
4638	union xfs_btree_key		*hkp;
4639	union xfs_btree_rec		*recp;
4640	struct xfs_btree_block		*block;
4641	int64_t				ldiff;
4642	int64_t				hdiff;
4643	int				level;
4644	struct xfs_buf			*bp;
4645	int				i;
4646	int				error;
4647
4648	/* Load the root of the btree. */
4649	level = cur->bc_nlevels - 1;
4650	cur->bc_ops->init_ptr_from_cur(cur, &ptr);
4651	error = xfs_btree_lookup_get_block(cur, level, &ptr, &block);
4652	if (error)
4653		return error;
4654	xfs_btree_get_block(cur, level, &bp);
4655	trace_xfs_btree_overlapped_query_range(cur, level, bp);
4656#ifdef DEBUG
4657	error = xfs_btree_check_block(cur, block, level, bp);
4658	if (error)
4659		goto out;
4660#endif
4661	cur->bc_ptrs[level] = 1;
4662
4663	while (level < cur->bc_nlevels) {
4664		block = xfs_btree_get_block(cur, level, &bp);
4665
4666		/* End of node, pop back towards the root. */
4667		if (cur->bc_ptrs[level] > be16_to_cpu(block->bb_numrecs)) {
4668pop_up:
4669			if (level < cur->bc_nlevels - 1)
4670				cur->bc_ptrs[level + 1]++;
4671			level++;
4672			continue;
4673		}
4674
4675		if (level == 0) {
4676			/* Handle a leaf node. */
4677			recp = xfs_btree_rec_addr(cur, cur->bc_ptrs[0], block);
4678
4679			cur->bc_ops->init_high_key_from_rec(&rec_hkey, recp);
4680			ldiff = cur->bc_ops->diff_two_keys(cur, &rec_hkey,
4681					low_key);
4682
4683			cur->bc_ops->init_key_from_rec(&rec_key, recp);
4684			hdiff = cur->bc_ops->diff_two_keys(cur, high_key,
4685					&rec_key);
4686
4687			/*
4688			 * If (record's high key >= query's low key) and
4689			 *    (query's high key >= record's low key), then
4690			 * this record overlaps the query range; callback.
4691			 */
4692			if (ldiff >= 0 && hdiff >= 0) {
4693				error = fn(cur, recp, priv);
4694				if (error)
4695					break;
4696			} else if (hdiff < 0) {
4697				/* Record is larger than high key; pop. */
4698				goto pop_up;
4699			}
4700			cur->bc_ptrs[level]++;
4701			continue;
4702		}
4703
4704		/* Handle an internal node. */
4705		lkp = xfs_btree_key_addr(cur, cur->bc_ptrs[level], block);
4706		hkp = xfs_btree_high_key_addr(cur, cur->bc_ptrs[level], block);
4707		pp = xfs_btree_ptr_addr(cur, cur->bc_ptrs[level], block);
4708
4709		ldiff = cur->bc_ops->diff_two_keys(cur, hkp, low_key);
4710		hdiff = cur->bc_ops->diff_two_keys(cur, high_key, lkp);
4711
4712		/*
4713		 * If (pointer's high key >= query's low key) and
4714		 *    (query's high key >= pointer's low key), then
4715		 * this record overlaps the query range; follow pointer.
4716		 */
4717		if (ldiff >= 0 && hdiff >= 0) {
4718			level--;
4719			error = xfs_btree_lookup_get_block(cur, level, pp,
4720					&block);
4721			if (error)
4722				goto out;
4723			xfs_btree_get_block(cur, level, &bp);
4724			trace_xfs_btree_overlapped_query_range(cur, level, bp);
4725#ifdef DEBUG
4726			error = xfs_btree_check_block(cur, block, level, bp);
4727			if (error)
4728				goto out;
4729#endif
4730			cur->bc_ptrs[level] = 1;
4731			continue;
4732		} else if (hdiff < 0) {
4733			/* The low key is larger than the upper range; pop. */
4734			goto pop_up;
4735		}
4736		cur->bc_ptrs[level]++;
4737	}
4738
4739out:
4740	/*
4741	 * If we don't end this function with the cursor pointing at a record
4742	 * block, a subsequent non-error cursor deletion will not release
4743	 * node-level buffers, causing a buffer leak.  This is quite possible
4744	 * with a zero-results range query, so release the buffers if we
4745	 * failed to return any results.
4746	 */
4747	if (cur->bc_bufs[0] == NULL) {
4748		for (i = 0; i < cur->bc_nlevels; i++) {
4749			if (cur->bc_bufs[i]) {
4750				xfs_trans_brelse(cur->bc_tp, cur->bc_bufs[i]);
4751				cur->bc_bufs[i] = NULL;
4752				cur->bc_ptrs[i] = 0;
4753				cur->bc_ra[i] = 0;
4754			}
4755		}
4756	}
4757
4758	return error;
4759}
4760
4761/*
4762 * Query a btree for all records overlapping a given interval of keys.  The
4763 * supplied function will be called with each record found; return one of the
4764 * XFS_BTREE_QUERY_RANGE_{CONTINUE,ABORT} values or the usual negative error
4765 * code.  This function returns -ECANCELED, zero, or a negative error code.
4766 */
4767int
4768xfs_btree_query_range(
4769	struct xfs_btree_cur		*cur,
4770	union xfs_btree_irec		*low_rec,
4771	union xfs_btree_irec		*high_rec,
4772	xfs_btree_query_range_fn	fn,
4773	void				*priv)
4774{
4775	union xfs_btree_rec		rec;
4776	union xfs_btree_key		low_key;
4777	union xfs_btree_key		high_key;
4778
4779	/* Find the keys of both ends of the interval. */
4780	cur->bc_rec = *high_rec;
4781	cur->bc_ops->init_rec_from_cur(cur, &rec);
4782	cur->bc_ops->init_key_from_rec(&high_key, &rec);
4783
4784	cur->bc_rec = *low_rec;
4785	cur->bc_ops->init_rec_from_cur(cur, &rec);
4786	cur->bc_ops->init_key_from_rec(&low_key, &rec);
4787
4788	/* Enforce low key < high key. */
4789	if (cur->bc_ops->diff_two_keys(cur, &low_key, &high_key) > 0)
4790		return -EINVAL;
4791
4792	if (!(cur->bc_flags & XFS_BTREE_OVERLAPPING))
4793		return xfs_btree_simple_query_range(cur, &low_key,
4794				&high_key, fn, priv);
4795	return xfs_btree_overlapped_query_range(cur, &low_key, &high_key,
4796			fn, priv);
4797}
4798
4799/* Query a btree for all records. */
4800int
4801xfs_btree_query_all(
4802	struct xfs_btree_cur		*cur,
4803	xfs_btree_query_range_fn	fn,
4804	void				*priv)
4805{
4806	union xfs_btree_key		low_key;
4807	union xfs_btree_key		high_key;
4808
4809	memset(&cur->bc_rec, 0, sizeof(cur->bc_rec));
4810	memset(&low_key, 0, sizeof(low_key));
4811	memset(&high_key, 0xFF, sizeof(high_key));
4812
4813	return xfs_btree_simple_query_range(cur, &low_key, &high_key, fn, priv);
4814}
4815
4816/*
4817 * Calculate the number of blocks needed to store a given number of records
4818 * in a short-format (per-AG metadata) btree.
4819 */
4820unsigned long long
4821xfs_btree_calc_size(
4822	uint			*limits,
4823	unsigned long long	len)
4824{
4825	int			level;
4826	int			maxrecs;
4827	unsigned long long	rval;
4828
4829	maxrecs = limits[0];
4830	for (level = 0, rval = 0; len > 1; level++) {
4831		len += maxrecs - 1;
4832		do_div(len, maxrecs);
4833		maxrecs = limits[1];
4834		rval += len;
4835	}
4836	return rval;
4837}
4838
4839static int
4840xfs_btree_count_blocks_helper(
4841	struct xfs_btree_cur	*cur,
4842	int			level,
4843	void			*data)
4844{
4845	xfs_extlen_t		*blocks = data;
4846	(*blocks)++;
4847
4848	return 0;
4849}
4850
4851/* Count the blocks in a btree and return the result in *blocks. */
4852int
4853xfs_btree_count_blocks(
4854	struct xfs_btree_cur	*cur,
4855	xfs_extlen_t		*blocks)
4856{
4857	*blocks = 0;
4858	return xfs_btree_visit_blocks(cur, xfs_btree_count_blocks_helper,
4859			XFS_BTREE_VISIT_ALL, blocks);
4860}
4861
4862/* Compare two btree pointers. */
4863int64_t
4864xfs_btree_diff_two_ptrs(
4865	struct xfs_btree_cur		*cur,
4866	const union xfs_btree_ptr	*a,
4867	const union xfs_btree_ptr	*b)
4868{
4869	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
4870		return (int64_t)be64_to_cpu(a->l) - be64_to_cpu(b->l);
4871	return (int64_t)be32_to_cpu(a->s) - be32_to_cpu(b->s);
4872}
4873
4874/* If there's an extent, we're done. */
4875STATIC int
4876xfs_btree_has_record_helper(
4877	struct xfs_btree_cur		*cur,
4878	union xfs_btree_rec		*rec,
4879	void				*priv)
4880{
4881	return -ECANCELED;
4882}
4883
4884/* Is there a record covering a given range of keys? */
4885int
4886xfs_btree_has_record(
4887	struct xfs_btree_cur	*cur,
4888	union xfs_btree_irec	*low,
4889	union xfs_btree_irec	*high,
4890	bool			*exists)
4891{
4892	int			error;
4893
4894	error = xfs_btree_query_range(cur, low, high,
4895			&xfs_btree_has_record_helper, NULL);
4896	if (error == -ECANCELED) {
4897		*exists = true;
4898		return 0;
4899	}
4900	*exists = false;
4901	return error;
4902}
4903
4904/* Are there more records in this btree? */
4905bool
4906xfs_btree_has_more_records(
4907	struct xfs_btree_cur	*cur)
4908{
4909	struct xfs_btree_block	*block;
4910	struct xfs_buf		*bp;
4911
4912	block = xfs_btree_get_block(cur, 0, &bp);
4913
4914	/* There are still records in this block. */
4915	if (cur->bc_ptrs[0] < xfs_btree_get_numrecs(block))
4916		return true;
4917
4918	/* There are more record blocks. */
4919	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
4920		return block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK);
4921	else
4922		return block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK);
4923}