xfs_da_btree.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,203 行 · 第 1/5 页

/*
 * Copyright (c) 2000-2004 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 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.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */

#include "xfs.h"

#include "xfs_macros.h"
#include "xfs_types.h"
#include "xfs_inum.h"
#include "xfs_log.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_alloc_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_attr_sf.h"
#include "xfs_dir_sf.h"
#include "xfs_dir2_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode_item.h"
#include "xfs_inode.h"
#include "xfs_bmap.h"
#include "xfs_da_btree.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"
#include "xfs_bit.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);


/*========================================================================
 * 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;
	INT_ZERO(node->hdr.info.forw, ARCH_CONVERT);
	INT_ZERO(node->hdr.info.back, ARCH_CONVERT);
	INT_SET(node->hdr.info.magic, ARCH_CONVERT, XFS_DA_NODE_MAGIC);
	INT_ZERO(node->hdr.info.pad, ARCH_CONVERT);
	INT_ZERO(node->hdr.count, ARCH_CONVERT);
	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:
#ifndef __KERNEL__
			return(ENOTTY);
#else
			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;
#endif
		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 (!INT_ISZERO(node->hdr.info.forw, ARCH_CONVERT)) {
		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;