aboutsummaryrefslogblamecommitdiffstats
path: root/fs/xfs/xfs_da_btree.c
blob: 473671fa5c13e1cff88cd4ad075ceecbf1a70ec6 (plain) (tree)
1
2
3
4
5
6
7
8
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
  

                                                 
  

                                                                 

                                             



                                                                   
  


                                                                       
   
                
                   
                      
                    
                    
                     






                      
                         
                           
                            
                             

                        
                        
                       
                      


                           
                     







                           















































                                                                                



                                                                 








































































                                                                             
























                                                                                





































































































































































































































                                                                                                 

                                                                    































































































































































































































































                                                                                                                     
                                                                       



                                              
                                                                           






























































































































































































































































                                                                                                 




                                                                   















































































































































































































































                                                                                                                              



                                                                                     

























                                                                                      




                                                                         








                                                                            



                                                                     





































                                                                            


                                                                       













































































































                                                                                                                 
                                                                   






























































































































































                                                                                                                              



                                                                              
































                                                                               
                                                 


                          

















                                                                            
                              

                            
























































































































































































































































































































































































































































































































































                                                                                                                              
                       



                                                                               




                                                                         









































































































































































                                                                                                   
           







































































































































































































































































                                                                              
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir_sf.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_bmap.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_dir_leaf.h"
#include "xfs_dir2_data.h"
#include "xfs_dir2_leaf.h"
#include "xfs_dir2_block.h"
#include "xfs_dir2_node.h"
#include "xfs_error.h"

/*
 * xfs_da_btree.c
 *
 * Routines to implement directories as Btrees of hashed names.
 */

/*========================================================================
 * Function prototypes for the kernel.
 *========================================================================*/

/*
 * Routines used for growing the Btree.
 */
STATIC int xfs_da_root_split(xfs_da_state_t *state,
					    xfs_da_state_blk_t *existing_root,
					    xfs_da_state_blk_t *new_child);
STATIC int xfs_da_node_split(xfs_da_state_t *state,
					    xfs_da_state_blk_t *existing_blk,
					    xfs_da_state_blk_t *split_blk,
					    xfs_da_state_blk_t *blk_to_add,
					    int treelevel,
					    int *result);
STATIC void xfs_da_node_rebalance(xfs_da_state_t *state,
					 xfs_da_state_blk_t *node_blk_1,
					 xfs_da_state_blk_t *node_blk_2);
STATIC void xfs_da_node_add(xfs_da_state_t *state,
				   xfs_da_state_blk_t *old_node_blk,
				   xfs_da_state_blk_t *new_node_blk);

/*
 * Routines used for shrinking the Btree.
 */
STATIC int xfs_da_root_join(xfs_da_state_t *state,
					   xfs_da_state_blk_t *root_blk);
STATIC int xfs_da_node_toosmall(xfs_da_state_t *state, int *retval);
STATIC void xfs_da_node_remove(xfs_da_state_t *state,
					      xfs_da_state_blk_t *drop_blk);
STATIC void xfs_da_node_unbalance(xfs_da_state_t *state,
					 xfs_da_state_blk_t *src_node_blk,
					 xfs_da_state_blk_t *dst_node_blk);

/*
 * Utility routines.
 */
STATIC uint	xfs_da_node_lasthash(xfs_dabuf_t *bp, int *count);
STATIC int	xfs_da_node_order(xfs_dabuf_t *node1_bp, xfs_dabuf_t *node2_bp);
STATIC xfs_dabuf_t *xfs_da_buf_make(int nbuf, xfs_buf_t **bps, inst_t *ra);
STATIC int	xfs_da_blk_unlink(xfs_da_state_t *state,
				  xfs_da_state_blk_t *drop_blk,
				  xfs_da_state_blk_t *save_blk);
STATIC void	xfs_da_state_kill_altpath(xfs_da_state_t *state);

/*========================================================================
 * Routines used for growing the Btree.
 *========================================================================*/

/*
 * Create the initial contents of an intermediate node.
 */
int
xfs_da_node_create(xfs_da_args_t *args, xfs_dablk_t blkno, int level,
				 xfs_dabuf_t **bpp, int whichfork)
{
	xfs_da_intnode_t *node;
	xfs_dabuf_t *bp;
	int error;
	xfs_trans_t *tp;

	tp = args->trans;
	error = xfs_da_get_buf(tp, args->dp, blkno, -1, &bp, whichfork);
	if (error)
		return(error);
	ASSERT(bp != NULL);
	node = bp->data;
	node->hdr.info.forw = 0;
	node->hdr.info.back = 0;
	INT_SET(node->hdr.info.magic, ARCH_CONVERT, XFS_DA_NODE_MAGIC);
	node->hdr.info.pad = 0;
	node->hdr.count = 0;
	INT_SET(node->hdr.level, ARCH_CONVERT, level);

	xfs_da_log_buf(tp, bp,
		XFS_DA_LOGRANGE(node, &node->hdr, sizeof(node->hdr)));

	*bpp = bp;
	return(0);
}

/*
 * Split a leaf node, rebalance, then possibly split
 * intermediate nodes, rebalance, etc.
 */
int							/* error */
xfs_da_split(xfs_da_state_t *state)
{
	xfs_da_state_blk_t *oldblk, *newblk, *addblk;
	xfs_da_intnode_t *node;
	xfs_dabuf_t *bp;
	int max, action, error, i;

	/*
	 * Walk back up the tree splitting/inserting/adjusting as necessary.
	 * If we need to insert and there isn't room, split the node, then
	 * decide which fragment to insert the new block from below into.
	 * Note that we may split the root this way, but we need more fixup.
	 */
	max = state->path.active - 1;
	ASSERT((max >= 0) && (max < XFS_DA_NODE_MAXDEPTH));
	ASSERT(state->path.blk[max].magic == XFS_ATTR_LEAF_MAGIC ||
	       state->path.blk[max].magic == XFS_DIRX_LEAF_MAGIC(state->mp));

	addblk = &state->path.blk[max];		/* initial dummy value */
	for (i = max; (i >= 0) && addblk; state->path.active--, i--) {
		oldblk = &state->path.blk[i];
		newblk = &state->altpath.blk[i];

		/*
		 * If a leaf node then
		 *     Allocate a new leaf node, then rebalance across them.
		 * else if an intermediate node then
		 *     We split on the last layer, must we split the node?
		 */
		switch (oldblk->magic) {
		case XFS_ATTR_LEAF_MAGIC:
			error = xfs_attr_leaf_split(state, oldblk, newblk);
			if ((error != 0) && (error != ENOSPC)) {
				return(error);	/* GROT: attr is inconsistent */
			}
			if (!error) {
				addblk = newblk;
				break;
			}
			/*
			 * Entry wouldn't fit, split the leaf again.
			 */
			state->extravalid = 1;
			if (state->inleaf) {
				state->extraafter = 0;	/* before newblk */
				error = xfs_attr_leaf_split(state, oldblk,
							    &state->extrablk);
			} else {
				state->extraafter = 1;	/* after newblk */
				error = xfs_attr_leaf_split(state, newblk,
							    &state->extrablk);
			}
			if (error)
				return(error);	/* GROT: attr inconsistent */
			addblk = newblk;
			break;
		case XFS_DIR_LEAF_MAGIC:
			ASSERT(XFS_DIR_IS_V1(state->mp));
			error = xfs_dir_leaf_split(state, oldblk, newblk);
			if ((error != 0) && (error != ENOSPC)) {
				return(error);	/* GROT: dir is inconsistent */
			}
			if (!error) {
				addblk = newblk;
				break;
			}
			/*
			 * Entry wouldn't fit, split the leaf again.
			 */
			state->extravalid = 1;
			if (state->inleaf) {
				state->extraafter = 0;	/* before newblk */
				error = xfs_dir_leaf_split(state, oldblk,
							   &state->extrablk);
				if (error)
					return(error);	/* GROT: dir incon. */
				addblk = newblk;
			} else {
				state->extraafter = 1;	/* after newblk */
				error = xfs_dir_leaf_split(state, newblk,
							   &state->extrablk);
				if (error)
					return(error);	/* GROT: dir incon. */
				addblk = newblk;
			}
			break;
		case XFS_DIR2_LEAFN_MAGIC:
			ASSERT(XFS_DIR_IS_V2(state->mp));
			error = xfs_dir2_leafn_split(state, oldblk, newblk);
			if (error)
				return error;
			addblk = newblk;
			break;
		case XFS_DA_NODE_MAGIC:
			error = xfs_da_node_split(state, oldblk, newblk, addblk,
							 max - i, &action);
			xfs_da_buf_done(addblk->bp);
			addblk->bp = NULL;
			if (error)
				return(error);	/* GROT: dir is inconsistent */
			/*
			 * Record the newly split block for the next time thru?
			 */
			if (action)
				addblk = newblk;
			else
				addblk = NULL;
			break;
		}

		/*
		 * Update the btree to show the new hashval for this child.
		 */
		xfs_da_fixhashpath(state, &state->path);
		/*
		 * If we won't need this block again, it's getting dropped
		 * from the active path by the loop control, so we need
		 * to mark it done now.
		 */
		if (i > 0 || !addblk)
			xfs_da_buf_done(oldblk->bp);
	}
	if (!addblk)
		return(0);

	/*
	 * Split the root node.
	 */
	ASSERT(state->path.active == 0);
	oldblk = &state->path.blk[0];
	error = xfs_da_root_split(state, oldblk, addblk);
	if (error) {
		xfs_da_buf_done(oldblk->bp);
		xfs_da_buf_done(addblk->bp);
		addblk->bp = NULL;
		return(error);	/* GROT: dir is inconsistent */
	}

	/*
	 * Update pointers to the node which used to be block 0 and
	 * just got bumped because of the addition of a new root node.
	 * There might be three blocks involved if a double split occurred,
	 * and the original block 0 could be at any position in the list.
	 */

	node = oldblk->bp->data;
	if (node->hdr.info.forw) {
		if (INT_GET(node->hdr.info.forw, ARCH_CONVERT) == addblk->blkno) {
			bp = addblk->bp;
		} else {
			ASSERT(state->extravalid);
			bp = state->extrablk.bp;
		}
		node = bp->data;
		INT_SET(node->hdr.info.back, ARCH_CONVERT, oldblk->blkno);
		xfs_da_log_buf(state->args->trans, bp,
		    XFS_DA_LOGRANGE(node, &node->hdr.info,
		    sizeof(node->hdr.info)));
	}
	node = oldblk->bp->data;
	if (INT_GET(node->hdr.info.back, ARCH_CONVERT)) {
		if (INT_GET(node->hdr.info.back, ARCH_CONVERT) == addblk->blkno) {
			bp = addblk->bp;
		} else {
			ASSERT(state->extravalid);
			bp = state->extrablk.bp;
		}
		node = bp->data;
		INT_SET(node->hdr.info.forw, ARCH_CONVERT, oldblk->blkno);
		xfs_da_log_buf(state->args->trans, bp,
		    XFS_DA_LOGRANGE(node, &node->hdr.info,
		    sizeof(node->hdr.info)));
	}
	xfs_da_buf_done(oldblk->bp);
	xfs_da_buf_done(addblk->bp);
	addblk->bp = NULL;
	return(0);
}

/*
 * Split the root.  We have to create a new root and point to the two
 * parts (the split old root) that we just created.  Copy block zero to
 * the EOF, extending the inode in process.
 */
STATIC int						/* error */
xfs_da_root_split(xfs_da_state_t *state, xfs_da_state_blk_t *blk1,
				 xfs_da_state_blk_t *blk2)
{
	xfs_da_intnode_t *node, *oldroot;
	xfs_da_args_t *args;
	xfs_dablk_t blkno;
	xfs_dabuf_t *bp;
	int error, size;
	xfs_inode_t *dp;
	xfs_trans_t *tp;
	xfs_mount_t *mp;
	xfs_dir2_leaf_t *leaf;

	/*
	 * Copy the existing (incorrect) block from the root node position
	 * to a free space somewhere.
	 */
	args = state->args;
	ASSERT(args != NULL);
	error = xfs_da_grow_inode(args, &blkno);
	if (error)
		return(error);
	dp = args->dp;
	tp = args->trans;
	mp = state->mp;
	error = xfs_da_get_buf(tp, dp, blkno, -1, &bp, args->whichfork);
	if (error)
		return(error);
	ASSERT(bp != NULL);
	node = bp->data;
	oldroot = blk1->bp->data;
	if (INT_GET(oldroot->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC) {
		size = (int)((char *)&oldroot->btree[INT_GET(oldroot->hdr.count, ARCH_CONVERT)] -
			     (char *)oldroot);
	} else {
		ASSERT(XFS_DIR_IS_V2(mp));
		ASSERT(INT_GET(oldroot->hdr.info.magic, ARCH_CONVERT) == XFS_DIR2_LEAFN_MAGIC);
		leaf = (xfs_dir2_leaf_t *)oldroot;
		size = (int)((char *)&leaf->ents[INT_GET(leaf->hdr.count, ARCH_CONVERT)] -
			     (char *)leaf);
	}
	memcpy(node, oldroot, size);
	xfs_da_log_buf(tp, bp, 0, size - 1);
	xfs_da_buf_done(blk1->bp);
	blk1->bp = bp;
	blk1->blkno = blkno;

	/*
	 * Set up the new root node.
	 */
	error = xfs_da_node_create(args,
		args->whichfork == XFS_DATA_FORK &&
		XFS_DIR_IS_V2(mp) ? mp->m_dirleafblk : 0,
		INT_GET(node->hdr.level, ARCH_CONVERT) + 1, &bp, args->whichfork);
	if (error)
		return(error);
	node = bp->data;
	INT_SET(node->btree[0].hashval, ARCH_CONVERT, blk1->hashval);
	INT_SET(node->btree[0].before, ARCH_CONVERT, blk1->blkno);
	INT_SET(node->btree[1].hashval, ARCH_CONVERT, blk2->hashval);
	INT_SET(node->btree[1].before, ARCH_CONVERT, blk2->blkno);
	INT_SET(node->hdr.count, ARCH_CONVERT, 2);

#ifdef DEBUG
	if (INT_GET(oldroot->hdr.info.magic, ARCH_CONVERT) == XFS_DIR2_LEAFN_MAGIC) {
		ASSERT(blk1->blkno >= mp->m_dirleafblk &&
		       blk1->blkno < mp->m_dirfreeblk);
		ASSERT(blk2->blkno >= mp->m_dirleafblk &&
		       blk2->blkno < mp->m_dirfreeblk);
	}
#endif

	/* Header is already logged by xfs_da_node_create */
	xfs_da_log_buf(tp, bp,
		XFS_DA_LOGRANGE(node, node->btree,
			sizeof(xfs_da_node_entry_t) * 2));
	xfs_da_buf_done(bp);

	return(0);
}

/*
 * Split the node, rebalance, then add the new entry.
 */
STATIC int						/* error */
xfs_da_node_split(xfs_da_state_t *state, xfs_da_state_blk_t *oldblk,
				 xfs_da_state_blk_t *newblk,
				 xfs_da_state_blk_t *addblk,
				 int treelevel, int *result)
{
	xfs_da_intnode_t *node;
	xfs_dablk_t blkno;
	int newcount, error;
	int useextra;

	node = oldblk->bp->data;
	ASSERT(INT_GET(node->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);

	/*
	 * With V2 the extra block is data or freespace.
	 */
	useextra = state->extravalid && (XFS_DIR_IS_V1(state->mp) ||
			state->args->whichfork == XFS_ATTR_FORK);
	newcount = 1 + useextra;
	/*
	 * Do we have to split the node?
	 */
	if ((INT_GET(node->hdr.count, ARCH_CONVERT) + newcount) > state->node_ents) {
		/*
		 * Allocate a new node, add to the doubly linked chain of
		 * nodes, then move some of our excess entries into it.
		 */
		error = xfs_da_grow_inode(state->args, &blkno);
		if (error)
			return(error);	/* GROT: dir is inconsistent */

		error = xfs_da_node_create(state->args, blkno, treelevel,
					   &newblk->bp, state->args->whichfork);
		if (error)
			return(error);	/* GROT: dir is inconsistent */
		newblk->blkno = blkno;
		newblk->magic = XFS_DA_NODE_MAGIC;
		xfs_da_node_rebalance(state, oldblk, newblk);
		error = xfs_da_blk_link(state, oldblk, newblk);
		if (error)
			return(error);
		*result = 1;
	} else {
		*result = 0;
	}

	/*
	 * Insert the new entry(s) into the correct block
	 * (updating last hashval in the process).
	 *
	 * xfs_da_node_add() inserts BEFORE the given index,
	 * and as a result of using node_lookup_int() we always
	 * point to a valid entry (not after one), but a split
	 * operation always results in a new block whose hashvals
	 * FOLLOW the current block.
	 *
	 * If we had double-split op below us, then add the extra block too.
	 */
	node = oldblk->bp->data;
	if (oldblk->index <= INT_GET(node->hdr.count, ARCH_CONVERT)) {
		oldblk->index++;
		xfs_da_node_add(state, oldblk, addblk);
		if (useextra) {
			if (state->extraafter)
				oldblk->index++;
			xfs_da_node_add(state, oldblk, &state->extrablk);
			state->extravalid = 0;
		}
	} else {
		newblk->index++;
		xfs_da_node_add(state, newblk, addblk);
		if (useextra) {
			if (state->extraafter)
				newblk->index++;
			xfs_da_node_add(state, newblk, &state->extrablk);
			state->extravalid = 0;
		}
	}

	return(0);
}

/*
 * Balance the btree elements between two intermediate nodes,
 * usually one full and one empty.
 *
 * NOTE: if blk2 is empty, then it will get the upper half of blk1.
 */
STATIC void
xfs_da_node_rebalance(xfs_da_state_t *state, xfs_da_state_blk_t *blk1,
				     xfs_da_state_blk_t *blk2)
{
	xfs_da_intnode_t *node1, *node2, *tmpnode;
	xfs_da_node_entry_t *btree_s, *btree_d;
	int count, tmp;
	xfs_trans_t *tp;

	node1 = blk1->bp->data;
	node2 = blk2->bp->data;
	/*
	 * Figure out how many entries need to move, and in which direction.
	 * Swap the nodes around if that makes it simpler.
	 */
	if ((INT_GET(node1->hdr.count, ARCH_CONVERT) > 0) && (INT_GET(node2->hdr.count, ARCH_CONVERT) > 0) &&
	    ((INT_GET(node2->btree[ 0 ].hashval, ARCH_CONVERT) < INT_GET(node1->btree[ 0 ].hashval, ARCH_CONVERT)) ||
	     (INT_GET(node2->btree[ INT_GET(node2->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT) <
	      INT_GET(node1->btree[ INT_GET(node1->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT)))) {
		tmpnode = node1;
		node1 = node2;
		node2 = tmpnode;
	}
	ASSERT(INT_GET(node1->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
	ASSERT(INT_GET(node2->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
	count = (INT_GET(node1->hdr.count, ARCH_CONVERT) - INT_GET(node2->hdr.count, ARCH_CONVERT)) / 2;
	if (count == 0)
		return;
	tp = state->args->trans;
	/*
	 * Two cases: high-to-low and low-to-high.
	 */
	if (count > 0) {
		/*
		 * Move elements in node2 up to make a hole.
		 */
		if ((tmp = INT_GET(node2->hdr.count, ARCH_CONVERT)) > 0) {
			tmp *= (uint)sizeof(xfs_da_node_entry_t);
			btree_s = &node2->btree[0];
			btree_d = &node2->btree[count];
			memmove(btree_d, btree_s, tmp);
		}

		/*
		 * Move the req'd B-tree elements from high in node1 to
		 * low in node2.
		 */
		INT_MOD(node2->hdr.count, ARCH_CONVERT, count);
		tmp = count * (uint)sizeof(xfs_da_node_entry_t);
		btree_s = &node1->btree[INT_GET(node1->hdr.count, ARCH_CONVERT) - count];
		btree_d = &node2->btree[0];
		memcpy(btree_d, btree_s, tmp);
		INT_MOD(node1->hdr.count, ARCH_CONVERT, -(count));

	} else {
		/*
		 * Move the req'd B-tree elements from low in node2 to
		 * high in node1.
		 */
		count = -count;
		tmp = count * (uint)sizeof(xfs_da_node_entry_t);
		btree_s = &node2->btree[0];
		btree_d = &node1->btree[INT_GET(node1->hdr.count, ARCH_CONVERT)];
		memcpy(btree_d, btree_s, tmp);
		INT_MOD(node1->hdr.count, ARCH_CONVERT, count);
		xfs_da_log_buf(tp, blk1->bp,
			XFS_DA_LOGRANGE(node1, btree_d, tmp));

		/*
		 * Move elements in node2 down to fill the hole.
		 */
		tmp  = INT_GET(node2->hdr.count, ARCH_CONVERT) - count;
		tmp *= (uint)sizeof(xfs_da_node_entry_t);
		btree_s = &node2->btree[count];
		btree_d = &node2->btree[0];
		memmove(btree_d, btree_s, tmp);
		INT_MOD(node2->hdr.count, ARCH_CONVERT, -(count));
	}

	/*
	 * Log header of node 1 and all current bits of node 2.
	 */
	xfs_da_log_buf(tp, blk1->bp,
		XFS_DA_LOGRANGE(node1, &node1->hdr, sizeof(node1->hdr)));
	xfs_da_log_buf(tp, blk2->bp,
		XFS_DA_LOGRANGE(node2, &node2->hdr,
			sizeof(node2->hdr) +
			sizeof(node2->btree[0]) * INT_GET(node2->hdr.count, ARCH_CONVERT)));

	/*
	 * Record the last hashval from each block for upward propagation.
	 * (note: don't use the swapped node pointers)
	 */
	node1 = blk1->bp->data;
	node2 = blk2->bp->data;
	blk1->hashval = INT_GET(node1->btree[ INT_GET(node1->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT);
	blk2->hashval = INT_GET(node2->btree[ INT_GET(node2->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT);

	/*
	 * Adjust the expected index for insertion.
	 */
	if (blk1->index >= INT_GET(node1->hdr.count, ARCH_CONVERT)) {
		blk2->index = blk1->index - INT_GET(node1->hdr.count, ARCH_CONVERT);
		blk1->index = INT_GET(node1->hdr.count, ARCH_CONVERT) + 1;	/* make it invalid */
	}
}

/*
 * Add a new entry to an intermediate node.
 */
STATIC void
xfs_da_node_add(xfs_da_state_t *state, xfs_da_state_blk_t *oldblk,
			       xfs_da_state_blk_t *newblk)
{
	xfs_da_intnode_t *node;
	xfs_da_node_entry_t *btree;
	int tmp;
	xfs_mount_t *mp;

	node = oldblk->bp->data;
	mp = state->mp;
	ASSERT(INT_GET(node->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
	ASSERT((oldblk->index >= 0) && (oldblk->index <= INT_GET(node->hdr.count, ARCH_CONVERT)));
	ASSERT(newblk->blkno != 0);
	if (state->args->whichfork == XFS_DATA_FORK && XFS_DIR_IS_V2(mp))
		ASSERT(newblk->blkno >= mp->m_dirleafblk &&
		       newblk->blkno < mp->m_dirfreeblk);

	/*
	 * We may need to make some room before we insert the new node.
	 */
	tmp = 0;
	btree = &node->btree[ oldblk->index ];
	if (oldblk->index < INT_GET(node->hdr.count, ARCH_CONVERT)) {
		tmp = (INT_GET(node->hdr.count, ARCH_CONVERT) - oldblk->index) * (uint)sizeof(*btree);
		memmove(btree + 1, btree, tmp);
	}
	INT_SET(btree->hashval, ARCH_CONVERT, newblk->hashval);
	INT_SET(btree->before, ARCH_CONVERT, newblk->blkno);
	xfs_da_log_buf(state->args->trans, oldblk->bp,
		XFS_DA_LOGRANGE(node, btree, tmp + sizeof(*btree)));
	INT_MOD(node->hdr.count, ARCH_CONVERT, +1);
	xfs_da_log_buf(state->args->trans, oldblk->bp,
		XFS_DA_LOGRANGE(node, &node->hdr, sizeof(node->hdr)));

	/*
	 * Copy the last hash value from the oldblk to propagate upwards.
	 */
	oldblk->hashval = INT_GET(node->btree[ INT_GET(node->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT);
}

/*========================================================================
 * Routines used for shrinking the Btree.
 *========================================================================*/

/*
 * Deallocate an empty leaf node, remove it from its parent,
 * possibly deallocating that block, etc...
 */
int
xfs_da_join(xfs_da_state_t *state)
{
	xfs_da_state_blk_t *drop_blk, *save_blk;
	int action, error;

	action = 0;
	drop_blk = &state->path.blk[ state->path.active-1 ];
	save_blk = &state->altpath.blk[ state->path.active-1 ];
	ASSERT(state->path.blk[0].magic == XFS_DA_NODE_MAGIC);
	ASSERT(drop_blk->magic == XFS_ATTR_LEAF_MAGIC ||
	       drop_blk->magic == XFS_DIRX_LEAF_MAGIC(state->mp));

	/*
	 * Walk back up the tree joining/deallocating as necessary.
	 * When we stop dropping blocks, break out.
	 */
	for (  ; state->path.active >= 2; drop_blk--, save_blk--,
		 state->path.active--) {
		/*
		 * See if we can combine the block with a neighbor.
		 *   (action == 0) => no options, just leave
		 *   (action == 1) => coalesce, then unlink
		 *   (action == 2) => block empty, unlink it
		 */
		switch (drop_blk->magic) {
		case XFS_ATTR_LEAF_MAGIC:
			error = xfs_attr_leaf_toosmall(state, &action);
			if (error)
				return(error);
			if (action == 0)
				return(0);
			xfs_attr_leaf_unbalance(state, drop_blk, save_blk);
			break;
		case XFS_DIR_LEAF_MAGIC:
			ASSERT(XFS_DIR_IS_V1(state->mp));
			error = xfs_dir_leaf_toosmall(state, &action);
			if (error)
				return(error);
			if (action == 0)
				return(0);
			xfs_dir_leaf_unbalance(state, drop_blk, save_blk);
			break;
		case XFS_DIR2_LEAFN_MAGIC:
			ASSERT(XFS_DIR_IS_V2(state->mp));
			error = xfs_dir2_leafn_toosmall(state, &action);
			if (error)
				return error;
			if (action == 0)
				return 0;
			xfs_dir2_leafn_unbalance(state, drop_blk, save_blk);
			break;
		case XFS_DA_NODE_MAGIC:
			/*
			 * Remove the offending node, fixup hashvals,
			 * check for a toosmall neighbor.
			 */
			xfs_da_node_remove(state, drop_blk);
			xfs_da_fixhashpath(state, &state->path);
			error = xfs_da_node_toosmall(state, &action);
			if (error)
				return(error);
			if (action == 0)
				return 0;
			xfs_da_node_unbalance(state, drop_blk, save_blk);
			break;
		}
		xfs_da_fixhashpath(state, &state->altpath);
		error = xfs_da_blk_unlink(state, drop_blk, save_blk);
		xfs_da_state_kill_altpath(state);
		if (error)
			return(error);
		error = xfs_da_shrink_inode(state->args, drop_blk->blkno,
							 drop_blk->bp);
		drop_blk->bp = NULL;
		if (error)
			return(error);
	}
	/*
	 * We joined all the way to the top.  If it turns out that
	 * we only have one entry in the root, make the child block
	 * the new root.
	 */
	xfs_da_node_remove(state, drop_blk);
	xfs_da_fixhashpath(state, &state->path);
	error = xfs_da_root_join(state, &state->path.blk[0]);
	return(error);
}

/*
 * We have only one entry in the root.  Copy the only remaining child of
 * the old root to block 0 as the new root node.
 */
STATIC int
xfs_da_root_join(xfs_da_state_t *state, xfs_da_state_blk_t *root_blk)
{
	xfs_da_intnode_t *oldroot;
	/* REFERENCED */
	xfs_da_blkinfo_t *blkinfo;
	xfs_da_args_t *args;
	xfs_dablk_t child;
	xfs_dabuf_t *bp;
	int error;

	args = state->args;
	ASSERT(args != NULL);
	ASSERT(root_blk->magic == XFS_DA_NODE_MAGIC);
	oldroot = root_blk->bp->data;
	ASSERT(INT_GET(oldroot->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
	ASSERT(!oldroot->hdr.info.forw);
	ASSERT(!oldroot->hdr.info.back);

	/*
	 * If the root has more than one child, then don't do anything.
	 */
	if (INT_GET(oldroot->hdr.count, ARCH_CONVERT) > 1)
		return(0);

	/*
	 * Read in the (only) child block, then copy those bytes into
	 * the root block's buffer and free the original child block.
	 */
	child = INT_GET(oldroot->btree[ 0 ].before, ARCH_CONVERT);
	ASSERT(child != 0);
	error = xfs_da_read_buf(args->trans, args->dp, child, -1, &bp,
					     args->whichfork);
	if (error)
		return(error);
	ASSERT(bp != NULL);
	blkinfo = bp->data;
	if (INT_GET(oldroot->hdr.level, ARCH_CONVERT) == 1) {
		ASSERT(INT_GET(blkinfo->magic, ARCH_CONVERT) == XFS_DIRX_LEAF_MAGIC(state->mp) ||
		       INT_GET(blkinfo->magic, ARCH_CONVERT) == XFS_ATTR_LEAF_MAGIC);
	} else {
		ASSERT(INT_GET(blkinfo->magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
	}
	ASSERT(!blkinfo->forw);
	ASSERT(!blkinfo->back);
	memcpy(root_blk->bp->data, bp->data, state->blocksize);
	xfs_da_log_buf(args->trans, root_blk->bp, 0, state->blocksize - 1);
	error = xfs_da_shrink_inode(args, child, bp);
	return(error);
}

/*
 * Check a node block and its neighbors to see if the block should be
 * collapsed into one or the other neighbor.  Always keep the block
 * with the smaller block number.
 * If the current block is over 50% full, don't try to join it, return 0.
 * If the block is empty, fill in the state structure and return 2.
 * If it can be collapsed, fill in the state structure and return 1.
 * If nothing can be done, return 0.
 */
STATIC int
xfs_da_node_toosmall(xfs_da_state_t *state, int *action)
{
	xfs_da_intnode_t *node;
	xfs_da_state_blk_t *blk;
	xfs_da_blkinfo_t *info;
	int count, forward, error, retval, i;
	xfs_dablk_t blkno;
	xfs_dabuf_t *bp;

	/*
	 * Check for the degenerate case of the block being over 50% full.
	 * If so, it's not worth even looking to see if we might be able
	 * to coalesce with a sibling.
	 */
	blk = &state->path.blk[ state->path.active-1 ];
	info = blk->bp->data;
	ASSERT(INT_GET(info->magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
	node = (xfs_da_intnode_t *)info;
	count = INT_GET(node->hdr.count, ARCH_CONVERT);
	if (count > (state->node_ents >> 1)) {
		*action = 0;	/* blk over 50%, don't try to join */
		return(0);	/* blk over 50%, don't try to join */
	}

	/*
	 * Check for the degenerate case of the block being empty.
	 * If the block is empty, we'll simply delete it, no need to
	 * coalesce it with a sibling block.  We choose (aribtrarily)
	 * to merge with the forward block unless it is NULL.
	 */
	if (count == 0) {
		/*
		 * Make altpath point to the block we want to keep and
		 * path point to the block we want to drop (this one).
		 */
		forward = info->forw;
		memcpy(&state->altpath, &state->path, sizeof(state->path));
		error = xfs_da_path_shift(state, &state->altpath, forward,
						 0, &retval);
		if (error)
			return(error);
		if (retval) {
			*action = 0;
		} else {
			*action = 2;
		}
		return(0);
	}

	/*
	 * Examine each sibling block to see if we can coalesce with
	 * at least 25% free space to spare.  We need to figure out
	 * whether to merge with the forward or the backward block.
	 * We prefer coalescing with the lower numbered sibling so as
	 * to shrink a directory over time.
	 */
	/* start with smaller blk num */
	forward = (INT_GET(info->forw, ARCH_CONVERT)
				< INT_GET(info->back, ARCH_CONVERT));
	for (i = 0; i < 2; forward = !forward, i++) {
		if (forward)
			blkno = INT_GET(info->forw, ARCH_CONVERT);
		else
			blkno = INT_GET(info->back, ARCH_CONVERT);
		if (blkno == 0)
			continue;
		error = xfs_da_read_buf(state->args->trans, state->args->dp,
					blkno, -1, &bp, state->args->whichfork);
		if (error)
			return(error);
		ASSERT(bp != NULL);

		node = (xfs_da_intnode_t *)info;
		count  = state->node_ents;
		count -= state->node_ents >> 2;
		count -= INT_GET(node->hdr.count, ARCH_CONVERT);
		node = bp->data;
		ASSERT(INT_GET(node->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
		count -= INT_GET(node->hdr.count, ARCH_CONVERT);
		xfs_da_brelse(state->args->trans, bp);
		if (count >= 0)
			break;	/* fits with at least 25% to spare */
	}
	if (i >= 2) {
		*action = 0;
		return(0);
	}

	/*
	 * Make altpath point to the block we want to keep (the lower
	 * numbered block) and path point to the block we want to drop.
	 */
	memcpy(&state->altpath, &state->path, sizeof(state->path));
	if (blkno < blk->blkno) {
		error = xfs_da_path_shift(state, &state->altpath, forward,
						 0, &retval);
		if (error) {
			return(error);
		}
		if (retval) {
			*action = 0;
			return(0);
		}
	} else {
		error = xfs_da_path_shift(state, &state->path, forward,
						 0, &retval);
		if (error) {
			return(error);
		}
		if (retval) {
			*action = 0;
			return(0);
		}
	}
	*action = 1;
	return(0);
}

/*
 * Walk back up the tree adjusting hash values as necessary,
 * when we stop making changes, return.
 */
void
xfs_da_fixhashpath(xfs_da_state_t *state, xfs_da_state_path_t *path)
{
	xfs_da_state_blk_t *blk;
	xfs_da_intnode_t *node;
	xfs_da_node_entry_t *btree;
	xfs_dahash_t lasthash=0;
	int level, count;

	level = path->active-1;
	blk = &path->blk[ level ];
	switch (blk->magic) {
	case XFS_ATTR_LEAF_MAGIC:
		lasthash = xfs_attr_leaf_lasthash(blk->bp, &count);
		if (count == 0)
			return;
		break;
	case XFS_DIR_LEAF_MAGIC:
		ASSERT(XFS_DIR_IS_V1(state->mp));
		lasthash = xfs_dir_leaf_lasthash(blk->bp, &count);
		if (count == 0)
			return;
		break;
	case XFS_DIR2_LEAFN_MAGIC:
		ASSERT(XFS_DIR_IS_V2(state->mp));
		lasthash = xfs_dir2_leafn_lasthash(blk->bp, &count);
		if (count == 0)
			return;
		break;
	case XFS_DA_NODE_MAGIC:
		lasthash = xfs_da_node_lasthash(blk->bp, &count);
		if (count == 0)
			return;
		break;
	}
	for (blk--, level--; level >= 0; blk--, level--) {
		node = blk->bp->data;
		ASSERT(INT_GET(node->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
		btree = &node->btree[ blk->index ];
		if (INT_GET(btree->hashval, ARCH_CONVERT) == lasthash)
			break;
		blk->hashval = lasthash;
		INT_SET(btree->hashval, ARCH_CONVERT, lasthash);
		xfs_da_log_buf(state->args->trans, blk->bp,
				  XFS_DA_LOGRANGE(node, btree, sizeof(*btree)));

		lasthash = INT_GET(node->btree[ INT_GET(node->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT);
	}
}

/*
 * Remove an entry from an intermediate node.
 */
STATIC void
xfs_da_node_remove(xfs_da_state_t *state, xfs_da_state_blk_t *drop_blk)
{
	xfs_da_intnode_t *node;
	xfs_da_node_entry_t *btree;
	int tmp;

	node = drop_blk->bp->data;
	ASSERT(drop_blk->index < INT_GET(node->hdr.count, ARCH_CONVERT));
	ASSERT(drop_blk->index >= 0);

	/*
	 * Copy over the offending entry, or just zero it out.
	 */
	btree = &node->btree[drop_blk->index];
	if (drop_blk->index < (INT_GET(node->hdr.count, ARCH_CONVERT)-1)) {
		tmp  = INT_GET(node->hdr.count, ARCH_CONVERT) - drop_blk->index - 1;
		tmp *= (uint)sizeof(xfs_da_node_entry_t);
		memmove(btree, btree + 1, tmp);
		xfs_da_log_buf(state->args->trans, drop_blk->bp,
		    XFS_DA_LOGRANGE(node, btree, tmp));
		btree = &node->btree[ INT_GET(node->hdr.count, ARCH_CONVERT)-1 ];
	}
	memset((char *)btree, 0, sizeof(xfs_da_node_entry_t));
	xfs_da_log_buf(state->args->trans, drop_blk->bp,
	    XFS_DA_LOGRANGE(node, btree, sizeof(*btree)));
	INT_MOD(node->hdr.count, ARCH_CONVERT, -1);
	xfs_da_log_buf(state->args->trans, drop_blk->bp,
	    XFS_DA_LOGRANGE(node, &node->hdr, sizeof(node->hdr)));

	/*
	 * Copy the last hash value from the block to propagate upwards.
	 */
	btree--;
	drop_blk->hashval = INT_GET(btree->hashval, ARCH_CONVERT);
}

/*
 * Unbalance the btree elements between two intermediate nodes,
 * move all Btree elements from one node into another.
 */
STATIC void
xfs_da_node_unbalance(xfs_da_state_t *state, xfs_da_state_blk_t *drop_blk,
				     xfs_da_state_blk_t *save_blk)
{
	xfs_da_intnode_t *drop_node, *save_node;
	xfs_da_node_entry_t *btree;
	int tmp;
	xfs_trans_t *tp;

	drop_node = drop_blk->bp->data;
	save_node = save_blk->bp->data;
	ASSERT(INT_GET(drop_node->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
	ASSERT(INT_GET(save_node->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
	tp = state->args->trans;

	/*
	 * If the dying block has lower hashvals, then move all the
	 * elements in the remaining block up to make a hole.
	 */
	if ((INT_GET(drop_node->btree[ 0 ].hashval, ARCH_CONVERT) < INT_GET(save_node->btree[ 0 ].hashval, ARCH_CONVERT)) ||
	    (INT_GET(drop_node->btree[ INT_GET(drop_node->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT) <
	     INT_GET(save_node->btree[ INT_GET(save_node->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT)))
	{
		btree = &save_node->btree[ INT_GET(drop_node->hdr.count, ARCH_CONVERT) ];
		tmp = INT_GET(save_node->hdr.count, ARCH_CONVERT) * (uint)sizeof(xfs_da_node_entry_t);
		memmove(btree, &save_node->btree[0], tmp);
		btree = &save_node->btree[0];
		xfs_da_log_buf(tp, save_blk->bp,
			XFS_DA_LOGRANGE(save_node, btree,
				(INT_GET(save_node->hdr.count, ARCH_CONVERT) + INT_GET(drop_node->hdr.count, ARCH_CONVERT)) *
				sizeof(xfs_da_node_entry_t)));
	} else {
		btree = &save_node->btree[ INT_GET(save_node->hdr.count, ARCH_CONVERT) ];
		xfs_da_log_buf(tp, save_blk->bp,
			XFS_DA_LOGRANGE(save_node, btree,
				INT_GET(drop_node->hdr.count, ARCH_CONVERT) *
				sizeof(xfs_da_node_entry_t)));
	}

	/*
	 * Move all the B-tree elements from drop_blk to save_blk.
	 */
	tmp = INT_GET(drop_node->hdr.count, ARCH_CONVERT) * (uint)sizeof(xfs_da_node_entry_t);
	memcpy(btree, &drop_node->btree[0], tmp);
	INT_MOD(save_node->hdr.count, ARCH_CONVERT, INT_GET(drop_node->hdr.count, ARCH_CONVERT));

	xfs_da_log_buf(tp, save_blk->bp,
		XFS_DA_LOGRANGE(save_node, &save_node->hdr,
			sizeof(save_node->hdr)));

	/*
	 * Save the last hashval in the remaining block for upward propagation.
	 */
	save_blk->hashval = INT_GET(save_node->btree[ INT_GET(save_node->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT);
}

/*========================================================================
 * Routines used for finding things in the Btree.
 *========================================================================*/

/*
 * Walk down the Btree looking for a particular filename, filling
 * in the state structure as we go.
 *
 * We will set the state structure to point to each of the elements
 * in each of the nodes where either the hashval is or should be.
 *
 * We support duplicate hashval's so for each entry in the current
 * node that could contain the desired hashval, descend.  This is a
 * pruned depth-first tree search.
 */
int							/* error */
xfs_da_node_lookup_int(xfs_da_state_t *state, int *result)
{
	xfs_da_state_blk_t *blk;
	xfs_da_blkinfo_t *curr;
	xfs_da_intnode_t *node;
	xfs_da_node_entry_t *btree;
	xfs_dablk_t blkno;
	int probe, span, max, error, retval;
	xfs_dahash_t hashval;
	xfs_da_args_t *args;

	args = state->args;

	/*
	 * Descend thru the B-tree searching each level for the right
	 * node to use, until the right hashval is found.
	 */
	if (args->whichfork == XFS_DATA_FORK && XFS_DIR_IS_V2(state->mp))
		blkno = state->mp->m_dirleafblk;
	else
		blkno = 0;
	for (blk = &state->path.blk[0], state->path.active = 1;
			 state->path.active <= XFS_DA_NODE_MAXDEPTH;
			 blk++, state->path.active++) {
		/*
		 * Read the next node down in the tree.
		 */
		blk->blkno = blkno;
		error = xfs_da_read_buf(args->trans, args->dp, blkno,
					-1, &blk->bp, args->whichfork);
		if (error) {
			blk->blkno = 0;
			state->path.active--;
			return(error);
		}
		curr = blk->bp->data;
		ASSERT(INT_GET(curr->magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC ||
		       INT_GET(curr->magic, ARCH_CONVERT) == XFS_DIRX_LEAF_MAGIC(state->mp) ||
		       INT_GET(curr->magic, ARCH_CONVERT) == XFS_ATTR_LEAF_MAGIC);

		/*
		 * Search an intermediate node for a match.
		 */
		blk->magic = INT_GET(curr->magic, ARCH_CONVERT);
		if (INT_GET(curr->magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC) {
			node = blk->bp->data;
			blk->hashval = INT_GET(node->btree[ INT_GET(node->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT);

			/*
			 * Binary search.  (note: small blocks will skip loop)
			 */
			max = INT_GET(node->hdr.count, ARCH_CONVERT);
			probe = span = max / 2;
			hashval = args->hashval;
			for (btree = &node->btree[probe]; span > 4;
				   btree = &node->btree[probe]) {
				span /= 2;
				if (INT_GET(btree->hashval, ARCH_CONVERT) < hashval)
					probe += span;
				else if (INT_GET(btree->hashval, ARCH_CONVERT) > hashval)
					probe -= span;
				else
					break;
			}
			ASSERT((probe >= 0) && (probe < max));
			ASSERT((span <= 4) || (INT_GET(btree->hashval, ARCH_CONVERT) == hashval));

			/*
			 * Since we may have duplicate hashval's, find the first
			 * matching hashval in the node.
			 */
			while ((probe > 0) && (INT_GET(btree->hashval, ARCH_CONVERT) >= hashval)) {
				btree--;
				probe--;
			}
			while ((probe < max) && (INT_GET(btree->hashval, ARCH_CONVERT) < hashval)) {
				btree++;
				probe++;
			}

			/*
			 * Pick the right block to descend on.
			 */
			if (probe == max) {
				blk->index = max-1;
				blkno = INT_GET(node->btree[ max-1 ].before, ARCH_CONVERT);
			} else {
				blk->index = probe;
				blkno = INT_GET(btree->before, ARCH_CONVERT);
			}
		}
		else if (INT_GET(curr->magic, ARCH_CONVERT) == XFS_ATTR_LEAF_MAGIC) {
			blk->hashval = xfs_attr_leaf_lasthash(blk->bp, NULL);
			break;
		}
		else if (INT_GET(curr->magic, ARCH_CONVERT) == XFS_DIR_LEAF_MAGIC) {
			blk->hashval = xfs_dir_leaf_lasthash(blk->bp, NULL);
			break;
		}
		else if (INT_GET(curr->magic, ARCH_CONVERT) == XFS_DIR2_LEAFN_MAGIC) {
			blk->hashval = xfs_dir2_leafn_lasthash(blk->bp, NULL);
			break;
		}
	}

	/*
	 * A leaf block that ends in the hashval that we are interested in
	 * (final hashval == search hashval) means that the next block may
	 * contain more entries with the same hashval, shift upward to the
	 * next leaf and keep searching.
	 */
	for (;;) {
		if (blk->magic == XFS_DIR_LEAF_MAGIC) {
			ASSERT(XFS_DIR_IS_V1(state->mp));
			retval = xfs_dir_leaf_lookup_int(blk->bp, args,
								  &blk->index);
		} else if (blk->magic == XFS_DIR2_LEAFN_MAGIC) {
			ASSERT(XFS_DIR_IS_V2(state->mp));
			retval = xfs_dir2_leafn_lookup_int(blk->bp, args,
							&blk->index, state);
		}
		else if (blk->magic == XFS_ATTR_LEAF_MAGIC) {
			retval = xfs_attr_leaf_lookup_int(blk->bp, args);
			blk->index = args->index;
			args->blkno = blk->blkno;
		}
		if (((retval == ENOENT) || (retval == ENOATTR)) &&
		    (blk->hashval == args->hashval)) {
			error = xfs_da_path_shift(state, &state->path, 1, 1,
							 &retval);
			if (error)
				return(error);
			if (retval == 0) {
				continue;
			}
			else if (blk->magic == XFS_ATTR_LEAF_MAGIC) {
				/* path_shift() gives ENOENT */
				retval = XFS_ERROR(ENOATTR);
			}
		}
		break;
	}
	*result = retval;
	return(0);
}

/*========================================================================
 * Utility routines.
 *========================================================================*/

/*
 * Link a new block into a doubly linked list of blocks (of whatever type).
 */
int							/* error */
xfs_da_blk_link(xfs_da_state_t *state, xfs_da_state_blk_t *old_blk,
			       xfs_da_state_blk_t *new_blk)
{
	xfs_da_blkinfo_t *old_info, *new_info, *tmp_info;
	xfs_da_args_t *args;
	int before=0, error;
	xfs_dabuf_t *bp;

	/*
	 * Set up environment.
	 */
	args = state->args;
	ASSERT(args != NULL);
	old_info = old_blk->bp->data;
	new_info = new_blk->bp->data;
	ASSERT(old_blk->magic == XFS_DA_NODE_MAGIC ||
	       old_blk->magic == XFS_DIRX_LEAF_MAGIC(state->mp) ||
	       old_blk->magic == XFS_ATTR_LEAF_MAGIC);
	ASSERT(old_blk->magic == INT_GET(old_info->magic, ARCH_CONVERT));
	ASSERT(new_blk->magic == INT_GET(new_info->magic, ARCH_CONVERT));
	ASSERT(old_blk->magic == new_blk->magic);

	switch (old_blk->magic) {
	case XFS_ATTR_LEAF_MAGIC:
		before = xfs_attr_leaf_order(old_blk->bp, new_blk->bp);
		break;
	case XFS_DIR_LEAF_MAGIC:
		ASSERT(XFS_DIR_IS_V1(state->mp));
		before = xfs_dir_leaf_order(old_blk->bp, new_blk->bp);
		break;
	case XFS_DIR2_LEAFN_MAGIC:
		ASSERT(XFS_DIR_IS_V2(state->mp));
		before = xfs_dir2_leafn_order(old_blk->bp, new_blk->bp);
		break;
	case XFS_DA_NODE_MAGIC:
		before = xfs_da_node_order(old_blk->bp, new_blk->bp);
		break;
	}

	/*
	 * Link blocks in appropriate order.
	 */
	if (before) {
		/*
		 * Link new block in before existing block.
		 */
		INT_SET(new_info->forw, ARCH_CONVERT, old_blk->blkno);
		new_info->back = old_info->back; /* INT_: direct copy */
		if (INT_GET(old_info->back, ARCH_CONVERT)) {
			error = xfs_da_read_buf(args->trans, args->dp,
						INT_GET(old_info->back,
							ARCH_CONVERT), -1, &bp,
						args->whichfork);
			if (error)
				return(error);
			ASSERT(bp != NULL);
			tmp_info = bp->data;
			ASSERT(INT_GET(tmp_info->magic, ARCH_CONVERT) == INT_GET(old_info->magic, ARCH_CONVERT));
			ASSERT(INT_GET(tmp_info->forw, ARCH_CONVERT) == old_blk->blkno);
			INT_SET(tmp_info->forw, ARCH_CONVERT, new_blk->blkno);
			xfs_da_log_buf(args->trans, bp, 0, sizeof(*tmp_info)-1);
			xfs_da_buf_done(bp);
		}
		INT_SET(old_info->back, ARCH_CONVERT, new_blk->blkno);
	} else {
		/*
		 * Link new block in after existing block.
		 */
		new_info->forw = old_info->forw; /* INT_: direct copy */
		INT_SET(new_info->back, ARCH_CONVERT, old_blk->blkno);
		if (INT_GET(old_info->forw, ARCH_CONVERT)) {
			error = xfs_da_read_buf(args->trans, args->dp,
						INT_GET(old_info->forw, ARCH_CONVERT), -1, &bp,
						args->whichfork);
			if (error)
				return(error);
			ASSERT(bp != NULL);
			tmp_info = bp->data;
			ASSERT(INT_GET(tmp_info->magic, ARCH_CONVERT)
				    == INT_GET(old_info->magic, ARCH_CONVERT));
			ASSERT(INT_GET(tmp_info->back, ARCH_CONVERT)
				    == old_blk->blkno);
			INT_SET(tmp_info->back, ARCH_CONVERT, new_blk->blkno);
			xfs_da_log_buf(args->trans, bp, 0, sizeof(*tmp_info)-1);
			xfs_da_buf_done(bp);
		}
		INT_SET(old_info->forw, ARCH_CONVERT, new_blk->blkno);
	}

	xfs_da_log_buf(args->trans, old_blk->bp, 0, sizeof(*tmp_info) - 1);
	xfs_da_log_buf(args->trans, new_blk->bp, 0, sizeof(*tmp_info) - 1);
	return(0);
}

/*
 * Compare two intermediate nodes for "order".
 */
STATIC int
xfs_da_node_order(xfs_dabuf_t *node1_bp, xfs_dabuf_t *node2_bp)
{
	xfs_da_intnode_t *node1, *node2;

	node1 = node1_bp->data;
	node2 = node2_bp->data;
	ASSERT((INT_GET(node1->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC) &&
	       (INT_GET(node2->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC));
	if ((INT_GET(node1->hdr.count, ARCH_CONVERT) > 0) && (INT_GET(node2->hdr.count, ARCH_CONVERT) > 0) &&
	    ((INT_GET(node2->btree[ 0 ].hashval, ARCH_CONVERT) <
	      INT_GET(node1->btree[ 0 ].hashval, ARCH_CONVERT)) ||
	     (INT_GET(node2->btree[ INT_GET(node2->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT) <
	      INT_GET(node1->btree[ INT_GET(node1->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT)))) {
		return(1);
	}
	return(0);
}

/*
 * Pick up the last hashvalue from an intermediate node.
 */
STATIC uint
xfs_da_node_lasthash(xfs_dabuf_t *bp, int *count)
{
	xfs_da_intnode_t *node;

	node = bp->data;
	ASSERT(INT_GET(node->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
	if (count)
		*count = INT_GET(node->hdr.count, ARCH_CONVERT);
	if (!node->hdr.count)
		return(0);
	return(INT_GET(node->btree[ INT_GET(node->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT));
}

/*
 * Unlink a block from a doubly linked list of blocks.
 */
STATIC int						/* error */
xfs_da_blk_unlink(xfs_da_state_t *state, xfs_da_state_blk_t *drop_blk,
				 xfs_da_state_blk_t *save_blk)
{
	xfs_da_blkinfo_t *drop_info, *save_info, *tmp_info;
	xfs_da_args_t *args;
	xfs_dabuf_t *bp;
	int error;

	/*
	 * Set up environment.
	 */
	args = state->args;
	ASSERT(args != NULL);
	save_info = save_blk->bp->data;
	drop_info = drop_blk->bp->data;
	ASSERT(save_blk->magic == XFS_DA_NODE_MAGIC ||
	       save_blk->magic == XFS_DIRX_LEAF_MAGIC(state->mp) ||
	       save_blk->magic == XFS_ATTR_LEAF_MAGIC);
	ASSERT(save_blk->magic == INT_GET(save_info->magic, ARCH_CONVERT));
	ASSERT(drop_blk->magic == INT_GET(drop_info->magic, ARCH_CONVERT));
	ASSERT(save_blk->magic == drop_blk->magic);
	ASSERT((INT_GET(save_info->forw, ARCH_CONVERT) == drop_blk->blkno) ||
	       (INT_GET(save_info->back, ARCH_CONVERT) == drop_blk->blkno));
	ASSERT((INT_GET(drop_info->forw, ARCH_CONVERT) == save_blk->blkno) ||
	       (INT_GET(drop_info->back, ARCH_CONVERT) == save_blk->blkno));

	/*
	 * Unlink the leaf block from the doubly linked chain of leaves.
	 */
	if (INT_GET(save_info->back, ARCH_CONVERT) == drop_blk->blkno) {
		save_info->back = drop_info->back; /* INT_: direct copy */
		if (INT_GET(drop_info->back, ARCH_CONVERT)) {
			error = xfs_da_read_buf(args->trans, args->dp,
						INT_GET(drop_info->back,
							ARCH_CONVERT), -1, &bp,
						args->whichfork);
			if (error)
				return(error);
			ASSERT(bp != NULL);
			tmp_info = bp->data;
			ASSERT(INT_GET(tmp_info->magic, ARCH_CONVERT) == INT_GET(save_info->magic, ARCH_CONVERT));
			ASSERT(INT_GET(tmp_info->forw, ARCH_CONVERT) == drop_blk->blkno);
			INT_SET(tmp_info->forw, ARCH_CONVERT, save_blk->blkno);
			xfs_da_log_buf(args->trans, bp, 0,
						    sizeof(*tmp_info) - 1);
			xfs_da_buf_done(bp);
		}
	} else {
		save_info->forw = drop_info->forw; /* INT_: direct copy */
		if (INT_GET(drop_info->forw, ARCH_CONVERT)) {
			error = xfs_da_read_buf(args->trans, args->dp,
						INT_GET(drop_info->forw, ARCH_CONVERT), -1, &bp,
						args->whichfork);
			if (error)
				return(error);
			ASSERT(bp != NULL);
			tmp_info = bp->data;
			ASSERT(INT_GET(tmp_info->magic, ARCH_CONVERT)
				    == INT_GET(save_info->magic, ARCH_CONVERT));
			ASSERT(INT_GET(tmp_info->back, ARCH_CONVERT)
				    == drop_blk->blkno);
			INT_SET(tmp_info->back, ARCH_CONVERT, save_blk->blkno);
			xfs_da_log_buf(args->trans, bp, 0,
						    sizeof(*tmp_info) - 1);
			xfs_da_buf_done(bp);
		}
	}

	xfs_da_log_buf(args->trans, save_blk->bp, 0, sizeof(*save_info) - 1);
	return(0);
}

/*
 * Move a path "forward" or "!forward" one block at the current level.
 *
 * This routine will adjust a "path" to point to the next block
 * "forward" (higher hashvalues) or "!forward" (lower hashvals) in the
 * Btree, including updating pointers to the intermediate nodes between
 * the new bottom and the root.
 */
int							/* error */
xfs_da_path_shift(xfs_da_state_t *state, xfs_da_state_path_t *path,
				 int forward, int release, int *result)
{
	xfs_da_state_blk_t *blk;
	xfs_da_blkinfo_t *info;
	xfs_da_intnode_t *node;
	xfs_da_args_t *args;
	xfs_dablk_t blkno=0;
	int level, error;

	/*
	 * Roll up the Btree looking for the first block where our
	 * current index is not at the edge of the block.  Note that
	 * we skip the bottom layer because we want the sibling block.
	 */
	args = state->args;
	ASSERT(args != NULL);
	ASSERT(path != NULL);
	ASSERT((path->active > 0) && (path->active < XFS_DA_NODE_MAXDEPTH));
	level = (path->active-1) - 1;	/* skip bottom layer in path */
	for (blk = &path->blk[level]; level >= 0; blk--, level--) {
		ASSERT(blk->bp != NULL);
		node = blk->bp->data;
		ASSERT(INT_GET(node->hdr.info.magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
		if (forward && (blk->index < INT_GET(node->hdr.count, ARCH_CONVERT)-1)) {
			blk->index++;
			blkno = INT_GET(node->btree[ blk->index ].before, ARCH_CONVERT);
			break;
		} else if (!forward && (blk->index > 0)) {
			blk->index--;
			blkno = INT_GET(node->btree[ blk->index ].before, ARCH_CONVERT);
			break;
		}
	}
	if (level < 0) {
		*result = XFS_ERROR(ENOENT);	/* we're out of our tree */
		ASSERT(args->oknoent);
		return(0);
	}

	/*
	 * Roll down the edge of the subtree until we reach the
	 * same depth we were at originally.
	 */
	for (blk++, level++; level < path->active; blk++, level++) {
		/*
		 * Release the old block.
		 * (if it's dirty, trans won't actually let go)
		 */
		if (release)
			xfs_da_brelse(args->trans, blk->bp);

		/*
		 * Read the next child block.
		 */
		blk->blkno = blkno;
		error = xfs_da_read_buf(args->trans, args->dp, blkno, -1,
						     &blk->bp, args->whichfork);
		if (error)
			return(error);
		ASSERT(blk->bp != NULL);
		info = blk->bp->data;
		ASSERT(INT_GET(info->magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC ||
		       INT_GET(info->magic, ARCH_CONVERT) == XFS_DIRX_LEAF_MAGIC(state->mp) ||
		       INT_GET(info->magic, ARCH_CONVERT) == XFS_ATTR_LEAF_MAGIC);
		blk->magic = INT_GET(info->magic, ARCH_CONVERT);
		if (INT_GET(info->magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC) {
			node = (xfs_da_intnode_t *)info;
			blk->hashval = INT_GET(node->btree[ INT_GET(node->hdr.count, ARCH_CONVERT)-1 ].hashval, ARCH_CONVERT);
			if (forward)
				blk->index = 0;
			else
				blk->index = INT_GET(node->hdr.count, ARCH_CONVERT)-1;
			blkno = INT_GET(node->btree[ blk->index ].before, ARCH_CONVERT);
		} else {
			ASSERT(level == path->active-1);
			blk->index = 0;
			switch(blk->magic) {
			case XFS_ATTR_LEAF_MAGIC:
				blk->hashval = xfs_attr_leaf_lasthash(blk->bp,
								      NULL);
				break;
			case XFS_DIR_LEAF_MAGIC:
				ASSERT(XFS_DIR_IS_V1(state->mp));
				blk->hashval = xfs_dir_leaf_lasthash(blk->bp,
								     NULL);
				break;
			case XFS_DIR2_LEAFN_MAGIC:
				ASSERT(XFS_DIR_IS_V2(state->mp));
				blk->hashval = xfs_dir2_leafn_lasthash(blk->bp,
								       NULL);
				break;
			default:
				ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC ||
				       blk->magic ==
				       XFS_DIRX_LEAF_MAGIC(state->mp));
				break;
			}
		}
	}
	*result = 0;
	return(0);
}


/*========================================================================
 * Utility routines.
 *========================================================================*/

/*
 * Implement a simple hash on a character string.
 * Rotate the hash value by 7 bits, then XOR each character in.
 * This is implemented with some source-level loop unrolling.
 */
xfs_dahash_t
xfs_da_hashname(const uchar_t *name, int namelen)
{
	xfs_dahash_t hash;

	/*
	 * Do four characters at a time as long as we can.
	 */
	for (hash = 0; namelen >= 4; namelen -= 4, name += 4)
		hash = (name[0] << 21) ^ (name[1] << 14) ^ (name[2] << 7) ^
		       (name[3] << 0) ^ rol32(hash, 7 * 4);

	/*
	 * Now do the rest of the characters.
	 */
	switch (namelen) {
	case 3:
		return (name[0] << 14) ^ (name[1] << 7) ^ (name[2] << 0) ^
		       rol32(hash, 7 * 3);
	case 2:
		return (name[0] << 7) ^ (name[1] << 0) ^ rol32(hash, 7 * 2);
	case 1:
		return (name[0] << 0) ^ rol32(hash, 7 * 1);
	default: /* case 0: */
		return hash;
	}
}

/*
 * Add a block to the btree ahead of the file.
 * Return the new block number to the caller.
 */
int
xfs_da_grow_inode(xfs_da_args_t *args, xfs_dablk_t *new_blkno)
{
	xfs_fileoff_t bno, b;
	xfs_bmbt_irec_t map;
	xfs_bmbt_irec_t	*mapp;
	xfs_inode_t *dp;
	int nmap, error, w, count, c, got, i, mapi;
	xfs_fsize_t size;
	xfs_trans_t *tp;
	xfs_mount_t *mp;

	dp = args->dp;
	mp = dp->i_mount;
	w = args->whichfork;
	tp = args->trans;
	/*
	 * For new directories adjust the file offset and block count.
	 */
	if (w == XFS_DATA_FORK && XFS_DIR_IS_V2(mp)) {
		bno = mp->m_dirleafblk;
		count = mp->m_dirblkfsbs;
	} else {
		bno = 0;
		count = 1;
	}
	/*
	 * Find a spot in the file space to put the new block.
	 */
	if ((error = xfs_bmap_first_unused(tp, dp, count, &bno, w))) {
		return error;
	}
	if (w == XFS_DATA_FORK && XFS_DIR_IS_V2(mp))
		ASSERT(bno >= mp->m_dirleafblk && bno < mp->m_dirfreeblk);
	/*
	 * Try mapping it in one filesystem block.
	 */
	nmap = 1;
	ASSERT(args->firstblock != NULL);
	if ((error = xfs_bmapi(tp, dp, bno, count,
			XFS_BMAPI_AFLAG(w)|XFS_BMAPI_WRITE|XFS_BMAPI_METADATA|
			XFS_BMAPI_CONTIG,
			args->firstblock, args->total, &map, &nmap,
			args->flist))) {
		return error;
	}
	ASSERT(nmap <= 1);
	if (nmap == 1) {
		mapp = &map;
		mapi = 1;
	}
	/*
	 * If we didn't get it and the block might work if fragmented,
	 * try without the CONTIG flag.  Loop until we get it all.
	 */
	else if (nmap == 0 && count > 1) {
		mapp = kmem_alloc(sizeof(*mapp) * count, KM_SLEEP);
		for (b = bno, mapi = 0; b < bno + count; ) {
			nmap = MIN(XFS_BMAP_MAX_NMAP, count);
			c = (int)(bno + count - b);
			if ((error = xfs_bmapi(tp, dp, b, c,
					XFS_BMAPI_AFLAG(w)|XFS_BMAPI_WRITE|
					XFS_BMAPI_METADATA,
					args->firstblock, args->total,
					&mapp[mapi], &nmap, args->flist))) {
				kmem_free(mapp, sizeof(*mapp) * count);
				return error;
			}
			if (nmap < 1)
				break;
			mapi += nmap;
			b = mapp[mapi - 1].br_startoff +
			    mapp[mapi - 1].br_blockcount;
		}
	} else {
		mapi = 0;
		mapp = NULL;
	}
	/*
	 * Count the blocks we got, make sure it matches the total.
	 */
	for (i = 0, got = 0; i < mapi; i++)
		got += mapp[i].br_blockcount;
	if (got != count || mapp[0].br_startoff != bno ||
	    mapp[mapi - 1].br_startoff + mapp[mapi - 1].br_blockcount !=
	    bno + count) {
		if (mapp != &map)
			kmem_free(mapp, sizeof(*mapp) * count);
		return XFS_ERROR(ENOSPC);
	}
	if (mapp != &map)
		kmem_free(mapp, sizeof(*mapp) * count);
	*new_blkno = (xfs_dablk_t)bno;
	/*
	 * For version 1 directories, adjust the file size if it changed.
	 */
	if (w == XFS_DATA_FORK && XFS_DIR_IS_V1(mp)) {
		ASSERT(mapi == 1);
		if ((error = xfs_bmap_last_offset(tp, dp, &bno, w)))
			return error;
		size = XFS_FSB_TO_B(mp, bno);
		if (size != dp->i_d.di_size) {
			dp->i_d.di_size = size;
			xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
		}
	}
	return 0;
}

/*
 * Ick.  We need to always be able to remove a btree block, even
 * if there's no space reservation because the filesystem is full.
 * This is called if xfs_bunmapi on a btree block fails due to ENOSPC.
 * It swaps the target block with the last block in the file.  The
 * last block in the file can always be removed since it can't cause
 * a bmap btree split to do that.
 */
STATIC int
xfs_da_swap_lastblock(xfs_da_args_t *args, xfs_dablk_t *dead_blknop,
		      xfs_dabuf_t **dead_bufp)
{
	xfs_dablk_t dead_blkno, last_blkno, sib_blkno, par_blkno;
	xfs_dabuf_t *dead_buf, *last_buf, *sib_buf, *par_buf;
	xfs_fileoff_t lastoff;
	xfs_inode_t *ip;
	xfs_trans_t *tp;
	xfs_mount_t *mp;
	int error, w, entno, level, dead_level;
	xfs_da_blkinfo_t *dead_info, *sib_info;
	xfs_da_intnode_t *par_node, *dead_node;
	xfs_dir_leafblock_t *dead_leaf;
	xfs_dir2_leaf_t *dead_leaf2;
	xfs_dahash_t dead_hash;

	dead_buf = *dead_bufp;
	dead_blkno = *dead_blknop;
	tp = args->trans;
	ip = args->dp;
	w = args->whichfork;
	ASSERT(w == XFS_DATA_FORK);
	mp = ip->i_mount;
	if (XFS_DIR_IS_V2(mp)) {
		lastoff = mp->m_dirfreeblk;
		error = xfs_bmap_last_before(tp, ip, &lastoff, w);
	} else
		error = xfs_bmap_last_offset(tp, ip, &lastoff, w);
	if (error)
		return error;
	if (unlikely(lastoff == 0)) {
		XFS_ERROR_REPORT("xfs_da_swap_lastblock(1)", XFS_ERRLEVEL_LOW,
				 mp);
		return XFS_ERROR(EFSCORRUPTED);
	}
	/*
	 * Read the last block in the btree space.
	 */
	last_blkno = (xfs_dablk_t)lastoff - mp->m_dirblkfsbs;
	if ((error = xfs_da_read_buf(tp, ip, last_blkno, -1, &last_buf, w)))
		return error;
	/*
	 * Copy the last block into the dead buffer and log it.
	 */
	memcpy(dead_buf->data, last_buf->data, mp->m_dirblksize);
	xfs_da_log_buf(tp, dead_buf, 0, mp->m_dirblksize - 1);
	dead_info = dead_buf->data;
	/*
	 * Get values from the moved block.
	 */
	if (INT_GET(dead_info->magic, ARCH_CONVERT) == XFS_DIR_LEAF_MAGIC) {
		ASSERT(XFS_DIR_IS_V1(mp));
		dead_leaf = (xfs_dir_leafblock_t *)dead_info;
		dead_level = 0;
		dead_hash =
			INT_GET(dead_leaf->entries[INT_GET(dead_leaf->hdr.count, ARCH_CONVERT) - 1].hashval, ARCH_CONVERT);
	} else if (INT_GET(dead_info->magic, ARCH_CONVERT) == XFS_DIR2_LEAFN_MAGIC) {
		ASSERT(XFS_DIR_IS_V2(mp));
		dead_leaf2 = (xfs_dir2_leaf_t *)dead_info;
		dead_level = 0;
		dead_hash = INT_GET(dead_leaf2->ents[INT_GET(dead_leaf2->hdr.count, ARCH_CONVERT) - 1].hashval, ARCH_CONVERT);
	} else {
		ASSERT(INT_GET(dead_info->magic, ARCH_CONVERT) == XFS_DA_NODE_MAGIC);
		dead_node = (xfs_da_intnode_t *)dead_info;
		dead_level = INT_GET(dead_node->hdr.level, ARCH_CONVERT);
		dead_hash = INT_GET(dead_node->btree[INT_GET(dead_node->hdr.count, ARCH_CONVERT) - 1].hashval, ARCH_CONVERT);
	}
	sib_buf = par_buf = NULL;
	/*
	 * If the moved block has a left sibling, fix up the pointers.
	 */
	if ((sib_blkno = INT_GET(dead_info->back, ARCH_CONVERT))) {
		if ((error = xfs_da_read_buf(tp, ip, sib_blkno, -1, &sib_buf, w)))
			goto done;
		sib_info = sib_buf->data;
		if (unlikely(
		    INT_GET(sib_info->forw, ARCH_CONVERT) != last_blkno ||
		    INT_GET(sib_info->magic, ARCH_CONVERT) != INT_GET(dead_info->magic, ARCH_CONVERT))) {
			XFS_ERROR_REPORT("xfs_da_swap_lastblock(2)",
					 XFS_ERRLEVEL_LOW, mp);
			error = XFS_ERROR(EFSCORRUPTED);
			goto done;
		}
		INT_SET(sib_info->forw, ARCH_CONVERT, dead_blkno);
		xfs_da_log_buf(tp, sib_buf,
			XFS_DA_LOGRANGE(sib_info, &sib_info->forw,
					sizeof(sib_info->forw)));
		xfs_da_buf_done(sib_buf);
		sib_buf = NULL;
	}
	/*
	 * If the moved block has a right sibling, fix up the pointers.
	 */
	if ((sib_blkno = INT_GET(dead_info->forw, ARCH_CONVERT))) {
		if ((error = xfs_da_read_buf(tp, ip, sib_blkno, -1, &sib_buf, w)))
			goto done;
		sib_info = sib_buf->data;
		if (unlikely(
		       INT_GET(sib_info->back, ARCH_CONVERT) != last_blkno
		    || INT_GET(sib_info->magic, ARCH_CONVERT)
				!= INT_GET(dead_info->magic, ARCH_CONVERT))) {
			XFS_ERROR_REPORT("xfs_da_swap_lastblock(3)",
					 XFS_ERRLEVEL_LOW, mp);
			error = XFS_ERROR(EFSCORRUPTED);
			goto done;
		}
		INT_SET(sib_info->back, ARCH_CONVERT, dead_blkno);
		xfs_da_log_buf(tp, sib_buf,
			XFS_DA_LOGRANGE(sib_info, &sib_info->back,
					sizeof(sib_info->back)));
		xfs_da_buf_done(sib_buf);
		sib_buf = NULL;
	}
	par_blkno = XFS_DIR_IS_V1(mp) ? 0 : mp->m_dirleafblk;
	level = -1;
	/*
	 * Walk down the tree looking for the parent of the moved block.
	 */
	for (;;) {
		if ((error = xfs_da_read_buf(tp, ip, par_blkno, -1, &par_buf, w)))
			goto done;
		par_node = par_buf->data;
		if (unlikely(
		    INT_GET(par_node->hdr.info.magic, ARCH_CONVERT) != XFS_DA_NODE_MAGIC ||
		    (level >= 0 && level != INT_GET(par_node->hdr.level, ARCH_CONVERT) + 1))) {
			XFS_ERROR_REPORT("xfs_da_swap_lastblock(4)",
					 XFS_ERRLEVEL_LOW, mp);
			error = XFS_ERROR(EFSCORRUPTED);
			goto done;
		}
		level = INT_GET(par_node->hdr.level, ARCH_CONVERT);
		for (entno = 0;
		     entno < INT_GET(par_node->hdr.count, ARCH_CONVERT) &&
		     INT_GET(par_node->btree[entno].hashval, ARCH_CONVERT) < dead_hash;
		     entno++)
			continue;
		if (unlikely(entno == INT_GET(par_node->hdr.count, ARCH_CONVERT))) {
			XFS_ERROR_REPORT("xfs_da_swap_lastblock(5)",
					 XFS_ERRLEVEL_LOW, mp);
			error = XFS_ERROR(EFSCORRUPTED);
			goto done;
		}
		par_blkno = INT_GET(par_node->btree[entno].before, ARCH_CONVERT);
		if (level == dead_level + 1)
			break;
		xfs_da_brelse(tp, par_buf);
		par_buf = NULL;
	}
	/*
	 * We're in the right parent block.
	 * Look for the right entry.
	 */
	for (;;) {
		for (;
		     entno < INT_GET(par_node->hdr.count, ARCH_CONVERT) &&
		     INT_GET(par_node->btree[entno].before, ARCH_CONVERT) != last_blkno;
		     entno++)
			continue;
		if (entno < INT_GET(par_node->hdr.count, ARCH_CONVERT))
			break;
		par_blkno = INT_GET(par_node->hdr.info.forw, ARCH_CONVERT);
		xfs_da_brelse(tp, par_buf);
		par_buf = NULL;
		if (unlikely(par_blkno == 0)) {
			XFS_ERROR_REPORT("xfs_da_swap_lastblock(6)",
					 XFS_ERRLEVEL_LOW, mp);
			error = XFS_ERROR(EFSCORRUPTED);
			goto done;
		}
		if ((error = xfs_da_read_buf(tp, ip, par_blkno, -1, &par_buf, w)))
			goto done;
		par_node = par_buf->data;
		if (unlikely(
		    INT_GET(par_node->hdr.level, ARCH_CONVERT) != level ||
		    INT_GET(par_node->hdr.info.magic, ARCH_CONVERT) != XFS_DA_NODE_MAGIC)) {
			XFS_ERROR_REPORT("xfs_da_swap_lastblock(7)",
					 XFS_ERRLEVEL_LOW, mp);
			error = XFS_ERROR(EFSCORRUPTED);
			goto done;
		}
		entno = 0;
	}
	/*
	 * Update the parent entry pointing to the moved block.
	 */
	INT_SET(par_node->btree[entno].before, ARCH_CONVERT, dead_blkno);
	xfs_da_log_buf(tp, par_buf,
		XFS_DA_LOGRANGE(par_node, &par_node->btree[entno].before,
				sizeof(par_node->btree[entno].before)));
	xfs_da_buf_done(par_buf);
	xfs_da_buf_done(dead_buf);
	*dead_blknop = last_blkno;
	*dead_bufp = last_buf;
	return 0;
done:
	if (par_buf)
		xfs_da_brelse(tp, par_buf);
	if (sib_buf)
		xfs_da_brelse(tp, sib_buf);
	xfs_da_brelse(tp, last_buf);
	return error;
}

/*
 * Remove a btree block from a directory or attribute.
 */
int
xfs_da_shrink_inode(xfs_da_args_t *args, xfs_dablk_t dead_blkno,
		    xfs_dabuf_t *dead_buf)
{
	xfs_inode_t *dp;
	int done, error, w, count;
	xfs_fileoff_t bno;
	xfs_fsize_t size;
	xfs_trans_t *tp;
	xfs_mount_t *mp;

	dp = args->dp;
	w = args->whichfork;
	tp = args->trans;
	mp = dp->i_mount;
	if (w == XFS_DATA_FORK && XFS_DIR_IS_V2(mp))
		count = mp->m_dirblkfsbs;
	else
		count = 1;
	for (;;) {
		/*
		 * Remove extents.  If we get ENOSPC for a dir we have to move
		 * the last block to the place we want to kill.
		 */
		if ((error = xfs_bunmapi(tp, dp, dead_blkno, count,
				XFS_BMAPI_AFLAG(w)|XFS_BMAPI_METADATA,
				0, args->firstblock, args->flist,
				&done)) == ENOSPC) {
			if (w != XFS_DATA_FORK)
				goto done;
			if ((error = xfs_da_swap_lastblock(args, &dead_blkno,
					&dead_buf)))
				goto done;
		} else if (error)
			goto done;
		else
			break;
	}
	ASSERT(done);
	xfs_da_binval(tp, dead_buf);
	/*
	 * Adjust the directory size for version 1.
	 */
	if (w == XFS_DATA_FORK && XFS_DIR_IS_V1(mp)) {
		if ((error = xfs_bmap_last_offset(tp, dp, &bno, w)))
			return error;
		size = XFS_FSB_TO_B(dp->i_mount, bno);
		if (size != dp->i_d.di_size) {
			dp->i_d.di_size = size;
			xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
		}
	}
	return 0;
done:
	xfs_da_binval(tp, dead_buf);
	return error;
}

/*
 * See if the mapping(s) for this btree block are valid, i.e.
 * don't contain holes, are logically contiguous, and cover the whole range.
 */
STATIC int
xfs_da_map_covers_blocks(
	int		nmap,
	xfs_bmbt_irec_t	*mapp,
	xfs_dablk_t	bno,
	int		count)
{
	int		i;
	xfs_fileoff_t	off;

	for (i = 0, off = bno; i < nmap; i++) {
		if (mapp[i].br_startblock == HOLESTARTBLOCK ||
		    mapp[i].br_startblock == DELAYSTARTBLOCK) {
			return 0;
		}
		if (off != mapp[i].br_startoff) {
			return 0;
		}
		off += mapp[i].br_blockcount;
	}
	return off == bno + count;
}

/*
 * Make a dabuf.
 * Used for get_buf, read_buf, read_bufr, and reada_buf.
 */
STATIC int
xfs_da_do_buf(
	xfs_trans_t	*trans,
	xfs_inode_t	*dp,
	xfs_dablk_t	bno,
	xfs_daddr_t	*mappedbnop,
	xfs_dabuf_t	**bpp,
	int		whichfork,
	int		caller,
	inst_t		*ra)
{
	xfs_buf_t	*bp = NULL;
	xfs_buf_t	**bplist;
	int		error=0;
	int		i;
	xfs_bmbt_irec_t	map;
	xfs_bmbt_irec_t	*mapp;
	xfs_daddr_t	mappedbno;
	xfs_mount_t	*mp;
	int		nbplist=0;
	int		nfsb;
	int		nmap;
	xfs_dabuf_t	*rbp;

	mp = dp->i_mount;
	if (whichfork == XFS_DATA_FORK && XFS_DIR_IS_V2(mp))
		nfsb = mp->m_dirblkfsbs;
	else
		nfsb = 1;
	mappedbno = *mappedbnop;
	/*
	 * Caller doesn't have a mapping.  -2 means don't complain
	 * if we land in a hole.
	 */
	if (mappedbno == -1 || mappedbno == -2) {
		/*
		 * Optimize the one-block case.
		 */
		if (nfsb == 1) {
			xfs_fsblock_t	fsb;

			if ((error =
			    xfs_bmapi_single(trans, dp, whichfork, &fsb,
				    (xfs_fileoff_t)bno))) {
				return error;
			}
			mapp = &map;
			if (fsb == NULLFSBLOCK) {
				nmap = 0;
			} else {
				map.br_startblock = fsb;
				map.br_startoff = (xfs_fileoff_t)bno;
				map.br_blockcount = 1;
				nmap = 1;
			}
		} else {
			mapp = kmem_alloc(sizeof(*mapp) * nfsb, KM_SLEEP);
			nmap = nfsb;
			if ((error = xfs_bmapi(trans, dp, (xfs_fileoff_t)bno,
					nfsb,
					XFS_BMAPI_METADATA |
						XFS_BMAPI_AFLAG(whichfork),
					NULL, 0, mapp, &nmap, NULL)))
				goto exit0;
		}
	} else {
		map.br_startblock = XFS_DADDR_TO_FSB(mp, mappedbno);
		map.br_startoff = (xfs_fileoff_t)bno;
		map.br_blockcount = nfsb;
		mapp = &map;
		nmap = 1;
	}
	if (!xfs_da_map_covers_blocks(nmap, mapp, bno, nfsb)) {
		error = mappedbno == -2 ? 0 : XFS_ERROR(EFSCORRUPTED);
		if (unlikely(error == EFSCORRUPTED)) {
			if (xfs_error_level >= XFS_ERRLEVEL_LOW) {
				int	i;
				cmn_err(CE_ALERT, "xfs_da_do_buf: bno %lld\n",
					(long long)bno);
				cmn_err(CE_ALERT, "dir: inode %lld\n",
					(long long)dp->i_ino);
				for (i = 0; i < nmap; i++) {
					cmn_err(CE_ALERT,
						"[%02d] br_startoff %lld br_startblock %lld br_blockcount %lld br_state %d\n",
						i,
						(long long)mapp[i].br_startoff,
						(long long)mapp[i].br_startblock,
						(long long)mapp[i].br_blockcount,
						mapp[i].br_state);
				}
			}
			XFS_ERROR_REPORT("xfs_da_do_buf(1)",
					 XFS_ERRLEVEL_LOW, mp);
		}
		goto exit0;
	}
	if (caller != 3 && nmap > 1) {
		bplist = kmem_alloc(sizeof(*bplist) * nmap, KM_SLEEP);
		nbplist = 0;
	} else
		bplist = NULL;
	/*
	 * Turn the mapping(s) into buffer(s).
	 */
	for (i = 0; i < nmap; i++) {
		int	nmapped;

		mappedbno = XFS_FSB_TO_DADDR(mp, mapp[i].br_startblock);
		if (i == 0)
			*mappedbnop = mappedbno;
		nmapped = (int)XFS_FSB_TO_BB(mp, mapp[i].br_blockcount);
		switch (caller) {
		case 0:
			bp = xfs_trans_get_buf(trans, mp->m_ddev_targp,
				mappedbno, nmapped, 0);
			error = bp ? XFS_BUF_GETERROR(bp) : XFS_ERROR(EIO);
			break;
		case 1:
		case 2:
			bp = NULL;
			error = xfs_trans_read_buf(mp, trans, mp->m_ddev_targp,
				mappedbno, nmapped, 0, &bp);
			break;
		case 3:
			xfs_baread(mp->m_ddev_targp, mappedbno, nmapped);
			error = 0;
			bp = NULL;
			break;
		}
		if (error) {
			if (bp)
				xfs_trans_brelse(trans, bp);
			goto exit1;
		}
		if (!bp)
			continue;
		if (caller == 1) {
			if (whichfork == XFS_ATTR_FORK) {
				XFS_BUF_SET_VTYPE_REF(bp, B_FS_ATTR_BTREE,
						XFS_ATTR_BTREE_REF);
			} else {
				XFS_BUF_SET_VTYPE_REF(bp, B_FS_DIR_BTREE,
						XFS_DIR_BTREE_REF);
			}
		}
		if (bplist) {
			bplist[nbplist++] = bp;
		}
	}
	/*
	 * Build a dabuf structure.
	 */
	if (bplist) {
		rbp = xfs_da_buf_make(nbplist, bplist, ra);
	} else if (bp)
		rbp = xfs_da_buf_make(1, &bp, ra);
	else
		rbp = NULL;
	/*
	 * For read_buf, check the magic number.
	 */
	if (caller == 1) {
		xfs_dir2_data_t		*data;
		xfs_dir2_free_t		*free;
		xfs_da_blkinfo_t	*info;
		uint			magic, magic1;

		info = rbp->data;
		data = rbp->data;
		free = rbp->data;
		magic = INT_GET(info->magic, ARCH_CONVERT);
		magic1 = INT_GET(data->hdr.magic, ARCH_CONVERT);
		if (unlikely(
		    XFS_TEST_ERROR((magic != XFS_DA_NODE_MAGIC) &&
				   (magic != XFS_DIR_LEAF_MAGIC) &&
				   (magic != XFS_ATTR_LEAF_MAGIC) &&
				   (magic != XFS_DIR2_LEAF1_MAGIC) &&
				   (magic != XFS_DIR2_LEAFN_MAGIC) &&
				   (magic1 != XFS_DIR2_BLOCK_MAGIC) &&
				   (magic1 != XFS_DIR2_DATA_MAGIC) &&
				   (INT_GET(free->hdr.magic, ARCH_CONVERT) != XFS_DIR2_FREE_MAGIC),
				mp, XFS_ERRTAG_DA_READ_BUF,
				XFS_RANDOM_DA_READ_BUF))) {
			xfs_buftrace("DA READ ERROR", rbp->bps[0]);
			XFS_CORRUPTION_ERROR("xfs_da_do_buf(2)",
					     XFS_ERRLEVEL_LOW, mp, info);
			error = XFS_ERROR(EFSCORRUPTED);
			xfs_da_brelse(trans, rbp);
			nbplist = 0;
			goto exit1;
		}
	}
	if (bplist) {
		kmem_free(bplist, sizeof(*bplist) * nmap);
	}
	if (mapp != &map) {
		kmem_free(mapp, sizeof(*mapp) * nfsb);
	}
	if (bpp)
		*bpp = rbp;
	return 0;
exit1:
	if (bplist) {
		for (i = 0; i < nbplist; i++)
			xfs_trans_brelse(trans, bplist[i]);
		kmem_free(bplist, sizeof(*bplist) * nmap);
	}
exit0:
	if (mapp != &map)
		kmem_free(mapp, sizeof(*mapp) * nfsb);
	if (bpp)
		*bpp = NULL;
	return error;
}

/*
 * Get a buffer for the dir/attr block.
 */
int
xfs_da_get_buf(
	xfs_trans_t	*trans,
	xfs_inode_t	*dp,
	xfs_dablk_t	bno,
	xfs_daddr_t		mappedbno,
	xfs_dabuf_t	**bpp,
	int		whichfork)
{
	return xfs_da_do_buf(trans, dp, bno, &mappedbno, bpp, whichfork, 0,
						 (inst_t *)__return_address);
}

/*
 * Get a buffer for the dir/attr block, fill in the contents.
 */
int
xfs_da_read_buf(
	xfs_trans_t	*trans,
	xfs_inode_t	*dp,
	xfs_dablk_t	bno,
	xfs_daddr_t		mappedbno,
	xfs_dabuf_t	**bpp,
	int		whichfork)
{
	return xfs_da_do_buf(trans, dp, bno, &mappedbno, bpp, whichfork, 1,
		(inst_t *)__return_address);
}

/*
 * Readahead the dir/attr block.
 */
xfs_daddr_t
xfs_da_reada_buf(
	xfs_trans_t	*trans,
	xfs_inode_t	*dp,
	xfs_dablk_t	bno,
	int		whichfork)
{
	xfs_daddr_t		rval;

	rval = -1;
	if (xfs_da_do_buf(trans, dp, bno, &rval, NULL, whichfork, 3,
			(inst_t *)__return_address))
		return -1;
	else
		return rval;
}

/*
 * Calculate the number of bits needed to hold i different values.
 */
uint
xfs_da_log2_roundup(uint i)
{
	uint rval;

	for (rval = 0; rval < NBBY * sizeof(i); rval++) {
		if ((1 << rval) >= i)
			break;
	}
	return(rval);
}

kmem_zone_t *xfs_da_state_zone;	/* anchor for state struct zone */
kmem_zone_t *xfs_dabuf_zone;		/* dabuf zone */

/*
 * Allocate a dir-state structure.
 * We don't put them on the stack since they're large.
 */
xfs_da_state_t *
xfs_da_state_alloc(void)
{
	return kmem_zone_zalloc(xfs_da_state_zone, KM_SLEEP);
}

/*
 * Kill the altpath contents of a da-state structure.
 */
STATIC void
xfs_da_state_kill_altpath(xfs_da_state_t *state)
{
	int	i;

	for (i = 0; i < state->altpath.active; i++) {
		if (state->altpath.blk[i].bp) {
			if (state->altpath.blk[i].bp != state->path.blk[i].bp)
				xfs_da_buf_done(state->altpath.blk[i].bp);
			state->altpath.blk[i].bp = NULL;
		}
	}
	state->altpath.active = 0;
}

/*
 * Free a da-state structure.
 */
void
xfs_da_state_free(xfs_da_state_t *state)
{
	int	i;

	xfs_da_state_kill_altpath(state);
	for (i = 0; i < state->path.active; i++) {
		if (state->path.blk[i].bp)
			xfs_da_buf_done(state->path.blk[i].bp);
	}
	if (state->extravalid && state->extrablk.bp)
		xfs_da_buf_done(state->extrablk.bp);
#ifdef DEBUG
	memset((char *)state, 0, sizeof(*state));
#endif /* DEBUG */
	kmem_zone_free(xfs_da_state_zone, state);
}

#ifdef XFS_DABUF_DEBUG
xfs_dabuf_t	*xfs_dabuf_global_list;
lock_t		xfs_dabuf_global_lock;
#endif

/*
 * Create a dabuf.
 */
/* ARGSUSED */
STATIC xfs_dabuf_t *
xfs_da_buf_make(int nbuf, xfs_buf_t **bps, inst_t *ra)
{
	xfs_buf_t	*bp;
	xfs_dabuf_t	*dabuf;
	int		i;
	int		off;

	if (nbuf == 1)
		dabuf = kmem_zone_alloc(xfs_dabuf_zone, KM_SLEEP);
	else
		dabuf = kmem_alloc(XFS_DA_BUF_SIZE(nbuf), KM_SLEEP);
	dabuf->dirty = 0;
#ifdef XFS_DABUF_DEBUG
	dabuf->ra = ra;
	dabuf->target = XFS_BUF_TARGET(bps[0]);
	dabuf->blkno = XFS_BUF_ADDR(bps[0]);
#endif
	if (nbuf == 1) {
		dabuf->nbuf = 1;
		bp = bps[0];
		dabuf->bbcount = (short)BTOBB(XFS_BUF_COUNT(bp));
		dabuf->data = XFS_BUF_PTR(bp);
		dabuf->bps[0] = bp;
	} else {
		dabuf->nbuf = nbuf;
		for (i = 0, dabuf->bbcount = 0; i < nbuf; i++) {
			dabuf->bps[i] = bp = bps[i];
			dabuf->bbcount += BTOBB(XFS_BUF_COUNT(bp));
		}
		dabuf->data = kmem_alloc(BBTOB(dabuf->bbcount), KM_SLEEP);
		for (i = off = 0; i < nbuf; i++, off += XFS_BUF_COUNT(bp)) {
			bp = bps[i];
			memcpy((char *)dabuf->data + off, XFS_BUF_PTR(bp),
				XFS_BUF_COUNT(bp));
		}
	}
#ifdef XFS_DABUF_DEBUG
	{
		SPLDECL(s);
		xfs_dabuf_t	*p;

		s = mutex_spinlock(&xfs_dabuf_global_lock);
		for (p = xfs_dabuf_global_list; p; p = p->next) {
			ASSERT(p->blkno != dabuf->blkno ||
			       p->target != dabuf->target);
		}
		dabuf->prev = NULL;
		if (xfs_dabuf_global_list)
			xfs_dabuf_global_list->prev = dabuf;
		dabuf->next = xfs_dabuf_global_list;
		xfs_dabuf_global_list = dabuf;
		mutex_spinunlock(&xfs_dabuf_global_lock, s);
	}
#endif
	return dabuf;
}

/*
 * Un-dirty a dabuf.
 */
STATIC void
xfs_da_buf_clean(xfs_dabuf_t *dabuf)
{
	xfs_buf_t	*bp;
	int		i;
	int		off;

	if (dabuf->dirty) {
		ASSERT(dabuf->nbuf > 1);
		dabuf->dirty = 0;
		for (i = off = 0; i < dabuf->nbuf;
				i++, off += XFS_BUF_COUNT(bp)) {
			bp = dabuf->bps[i];
			memcpy(XFS_BUF_PTR(bp), (char *)dabuf->data + off,
				XFS_BUF_COUNT(bp));
		}
	}
}

/*
 * Release a dabuf.
 */
void
xfs_da_buf_done(xfs_dabuf_t *dabuf)
{
	ASSERT(dabuf);
	ASSERT(dabuf->nbuf && dabuf->data && dabuf->bbcount && dabuf->bps[0]);
	if (dabuf->dirty)
		xfs_da_buf_clean(dabuf);
	if (dabuf->nbuf > 1)
		kmem_free(dabuf->data, BBTOB(dabuf->bbcount));
#ifdef XFS_DABUF_DEBUG
	{
		SPLDECL(s);

		s = mutex_spinlock(&xfs_dabuf_global_lock);
		if (dabuf->prev)
			dabuf->prev->next = dabuf->next;
		else
			xfs_dabuf_global_list = dabuf->next;
		if (dabuf->next)
			dabuf->next->prev = dabuf->prev;
		mutex_spinunlock(&xfs_dabuf_global_lock, s);
	}
	memset(dabuf, 0, XFS_DA_BUF_SIZE(dabuf->nbuf));
#endif
	if (dabuf->nbuf == 1)
		kmem_zone_free(xfs_dabuf_zone, dabuf);
	else
		kmem_free(dabuf, XFS_DA_BUF_SIZE(dabuf->nbuf));
}

/*
 * Log transaction from a dabuf.
 */
void
xfs_da_log_buf(xfs_trans_t *tp, xfs_dabuf_t *dabuf, uint first, uint last)
{
	xfs_buf_t	*bp;
	uint		f;
	int		i;
	uint		l;
	int		off;

	ASSERT(dabuf->nbuf && dabuf->data && dabuf->bbcount && dabuf->bps[0]);
	if (dabuf->nbuf == 1) {
		ASSERT(dabuf->data == (void *)XFS_BUF_PTR(dabuf->bps[0]));
		xfs_trans_log_buf(tp, dabuf->bps[0], first, last);
		return;
	}
	dabuf->dirty = 1;
	ASSERT(first <= last);
	for (i = off = 0; i < dabuf->nbuf; i++, off += XFS_BUF_COUNT(bp)) {
		bp = dabuf->bps[i];
		f = off;
		l = f + XFS_BUF_COUNT(bp) - 1;
		if (f < first)
			f = first;
		if (l > last)
			l = last;
		if (f <= l)
			xfs_trans_log_buf(tp, bp, f - off, l - off);
		/*
		 * B_DONE is set by xfs_trans_log buf.
		 * If we don't set it on a new buffer (get not read)
		 * then if we don't put anything in the buffer it won't
		 * be set, and at commit it it released into the cache,
		 * and then a read will fail.
		 */
		else if (!(XFS_BUF_ISDONE(bp)))
		  XFS_BUF_DONE(bp);
	}
	ASSERT(last < off);
}

/*
 * Release dabuf from a transaction.
 * Have to free up the dabuf before the buffers are released,
 * since the synchronization on the dabuf is really the lock on the buffer.
 */
void
xfs_da_brelse(xfs_trans_t *tp, xfs_dabuf_t *dabuf)
{
	xfs_buf_t	*bp;
	xfs_buf_t	**bplist;
	int		i;
	int		nbuf;

	ASSERT(dabuf->nbuf && dabuf->data && dabuf->bbcount && dabuf->bps[0]);
	if ((nbuf = dabuf->nbuf) == 1) {
		bplist = &bp;
		bp = dabuf->bps[0];
	} else {
		bplist = kmem_alloc(nbuf * sizeof(*bplist), KM_SLEEP);
		memcpy(bplist, dabuf->bps, nbuf * sizeof(*bplist));
	}
	xfs_da_buf_done(dabuf);
	for (i = 0; i < nbuf; i++)
		xfs_trans_brelse(tp, bplist[i]);
	if (bplist != &bp)
		kmem_free(bplist, nbuf * sizeof(*bplist));
}

/*
 * Invalidate dabuf from a transaction.
 */
void
xfs_da_binval(xfs_trans_t *tp, xfs_dabuf_t *dabuf)
{
	xfs_buf_t	*bp;
	xfs_buf_t	**bplist;
	int		i;
	int		nbuf;

	ASSERT(dabuf->nbuf && dabuf->data && dabuf->bbcount && dabuf->bps[0]);
	if ((nbuf = dabuf->nbuf) == 1) {
		bplist = &bp;
		bp = dabuf->bps[0];
	} else {
		bplist = kmem_alloc(nbuf * sizeof(*bplist), KM_SLEEP);
		memcpy(bplist, dabuf->bps, nbuf * sizeof(*bplist));
	}
	xfs_da_buf_done(dabuf);
	for (i = 0; i < nbuf; i++)
		xfs_trans_binval(tp, bplist[i]);
	if (bplist != &bp)
		kmem_free(bplist, nbuf * sizeof(*bplist));
}

/*
 * Get the first daddr from a dabuf.
 */
xfs_daddr_t
xfs_da_blkno(xfs_dabuf_t *dabuf)
{
	ASSERT(dabuf->nbuf);
	ASSERT(dabuf->data);
	return XFS_BUF_ADDR(dabuf->bps[0]);
}