/fs/yaffs2/yaffs_guts.c

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/*
 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
 *
 * Copyright (C) 2002-2010 Aleph One Ltd.
 *   for Toby Churchill Ltd and Brightstar Engineering
 *
 * Created by Charles Manning <charles@aleph1.co.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include "yportenv.h"
#include "yaffs_trace.h"

#include "yaffs_guts.h"
#include "yaffs_tagsvalidity.h"
#include "yaffs_getblockinfo.h"

#include "yaffs_tagscompat.h"

#include "yaffs_nand.h"

#include "yaffs_yaffs1.h"
#include "yaffs_yaffs2.h"
#include "yaffs_bitmap.h"
#include "yaffs_verify.h"

#include "yaffs_nand.h"
#include "yaffs_packedtags2.h"

#include "yaffs_nameval.h"
#include "yaffs_allocator.h"

#include "yaffs_attribs.h"

#define YAFFS_GC_GOOD_ENOUGH 2
#define YAFFS_GC_PASSIVE_THRESHOLD 4

#include "yaffs_ecc.h"


static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
			     const u8 * buffer, int n_bytes, int use_reserve);




static void yaffs_addr_to_chunk(struct yaffs_dev *dev, loff_t addr,
				int *chunk_out, u32 * offset_out)
{
	int chunk;
	u32 offset;

	chunk = (u32) (addr >> dev->chunk_shift);

	if (dev->chunk_div == 1) {
		
		offset = (u32) (addr & dev->chunk_mask);
	} else {
		

		loff_t chunk_base;

		chunk /= dev->chunk_div;

		chunk_base = ((loff_t) chunk) * dev->data_bytes_per_chunk;
		offset = (u32) (addr - chunk_base);
	}

	*chunk_out = chunk;
	*offset_out = offset;
}


static u32 calc_shifts_ceiling(u32 x)
{
	int extra_bits;
	int shifts;

	shifts = extra_bits = 0;

	while (x > 1) {
		if (x & 1)
			extra_bits++;
		x >>= 1;
		shifts++;
	}

	if (extra_bits)
		shifts++;

	return shifts;
}


static u32 calc_shifts(u32 x)
{
	u32 shifts;

	shifts = 0;

	if (!x)
		return 0;

	while (!(x & 1)) {
		x >>= 1;
		shifts++;
	}

	return shifts;
}


static int yaffs_init_tmp_buffers(struct yaffs_dev *dev)
{
	int i;
	u8 *buf = (u8 *) 1;

	memset(dev->temp_buffer, 0, sizeof(dev->temp_buffer));

	for (i = 0; buf && i < YAFFS_N_TEMP_BUFFERS; i++) {
		dev->temp_buffer[i].line = 0;	
		dev->temp_buffer[i].buffer = buf =
		    kmalloc(dev->param.total_bytes_per_chunk, GFP_NOFS);
	}

	return buf ? YAFFS_OK : YAFFS_FAIL;
}

u8 *yaffs_get_temp_buffer(struct yaffs_dev * dev, int line_no)
{
	int i, j;

	dev->temp_in_use++;
	if (dev->temp_in_use > dev->max_temp)
		dev->max_temp = dev->temp_in_use;

	for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
		if (dev->temp_buffer[i].line == 0) {
			dev->temp_buffer[i].line = line_no;
			if ((i + 1) > dev->max_temp) {
				dev->max_temp = i + 1;
				for (j = 0; j <= i; j++)
					dev->temp_buffer[j].max_line =
					    dev->temp_buffer[j].line;
			}

			return dev->temp_buffer[i].buffer;
		}
	}

	yaffs_trace(YAFFS_TRACE_BUFFERS,
		"Out of temp buffers at line %d, other held by lines:",
		line_no);
	for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++)
		yaffs_trace(YAFFS_TRACE_BUFFERS," %d", dev->temp_buffer[i].line);


	dev->unmanaged_buffer_allocs++;
	return kmalloc(dev->data_bytes_per_chunk, GFP_NOFS);

}

void yaffs_release_temp_buffer(struct yaffs_dev *dev, u8 * buffer, int line_no)
{
	int i;

	dev->temp_in_use--;

	for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
		if (dev->temp_buffer[i].buffer == buffer) {
			dev->temp_buffer[i].line = 0;
			return;
		}
	}

	if (buffer) {
		
		yaffs_trace(YAFFS_TRACE_BUFFERS,
		  "Releasing unmanaged temp buffer in line %d",
		   line_no);
		kfree(buffer);
		dev->unmanaged_buffer_deallocs++;
	}

}

int yaffs_is_managed_tmp_buffer(struct yaffs_dev *dev, const u8 * buffer)
{
	int i;

	for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++) {
		if (dev->temp_buffer[i].buffer == buffer)
			return 1;
	}

	for (i = 0; i < dev->param.n_caches; i++) {
		if (dev->cache[i].data == buffer)
			return 1;
	}

	if (buffer == dev->checkpt_buffer)
		return 1;

	yaffs_trace(YAFFS_TRACE_ALWAYS,
	  "yaffs: unmaged buffer detected.");
	return 0;
}


static void yaffs_handle_chunk_wr_ok(struct yaffs_dev *dev, int nand_chunk,
				     const u8 * data,
				     const struct yaffs_ext_tags *tags)
{
	dev = dev;
	nand_chunk = nand_chunk;
	data = data;
	tags = tags;
}

static void yaffs_handle_chunk_update(struct yaffs_dev *dev, int nand_chunk,
				      const struct yaffs_ext_tags *tags)
{
	dev = dev;
	nand_chunk = nand_chunk;
	tags = tags;
}

void yaffs_handle_chunk_error(struct yaffs_dev *dev,
			      struct yaffs_block_info *bi)
{
	if (!bi->gc_prioritise) {
		bi->gc_prioritise = 1;
		dev->has_pending_prioritised_gc = 1;
		bi->chunk_error_strikes++;

		if (bi->chunk_error_strikes > 3) {
			bi->needs_retiring = 1;	
			yaffs_trace(YAFFS_TRACE_ALWAYS, "yaffs: Block struck out");

		}
	}
}

static void yaffs_handle_chunk_wr_error(struct yaffs_dev *dev, int nand_chunk,
					int erased_ok)
{
	int flash_block = nand_chunk / dev->param.chunks_per_block;
	struct yaffs_block_info *bi = yaffs_get_block_info(dev, flash_block);

	yaffs_handle_chunk_error(dev, bi);

	if (erased_ok) {
		
		bi->needs_retiring = 1;
		yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
		  "**>> Block %d needs retiring", flash_block);
	}

	
	yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
	yaffs_skip_rest_of_block(dev);
}



static inline int yaffs_hash_fn(int n)
{
	n = abs(n);
	return n % YAFFS_NOBJECT_BUCKETS;
}


struct yaffs_obj *yaffs_root(struct yaffs_dev *dev)
{
	return dev->root_dir;
}

struct yaffs_obj *yaffs_lost_n_found(struct yaffs_dev *dev)
{
	return dev->lost_n_found;
}


int yaffs_check_ff(u8 * buffer, int n_bytes)
{
	
	while (n_bytes--) {
		if (*buffer != 0xFF)
			return 0;
		buffer++;
	}
	return 1;
}

static int yaffs_check_chunk_erased(struct yaffs_dev *dev, int nand_chunk)
{
	int retval = YAFFS_OK;
	u8 *data = yaffs_get_temp_buffer(dev, __LINE__);
	struct yaffs_ext_tags tags;
	int result;

	result = yaffs_rd_chunk_tags_nand(dev, nand_chunk, data, &tags);

	if (tags.ecc_result > YAFFS_ECC_RESULT_NO_ERROR)
		retval = YAFFS_FAIL;

	if (!yaffs_check_ff(data, dev->data_bytes_per_chunk) ||
		tags.chunk_used) {
		yaffs_trace(YAFFS_TRACE_NANDACCESS, "Chunk %d not erased", nand_chunk);
		retval = YAFFS_FAIL;
	}

	yaffs_release_temp_buffer(dev, data, __LINE__);

	return retval;

}

static int yaffs_verify_chunk_written(struct yaffs_dev *dev,
				      int nand_chunk,
				      const u8 * data,
				      struct yaffs_ext_tags *tags)
{
	int retval = YAFFS_OK;
	struct yaffs_ext_tags temp_tags;
	u8 *buffer = yaffs_get_temp_buffer(dev, __LINE__);
	int result;

	result = yaffs_rd_chunk_tags_nand(dev, nand_chunk, buffer, &temp_tags);
	if (memcmp(buffer, data, dev->data_bytes_per_chunk) ||
	    temp_tags.obj_id != tags->obj_id ||
	    temp_tags.chunk_id != tags->chunk_id ||
	    temp_tags.n_bytes != tags->n_bytes)
		retval = YAFFS_FAIL;

	yaffs_release_temp_buffer(dev, buffer, __LINE__);

	return retval;
}


int yaffs_check_alloc_available(struct yaffs_dev *dev, int n_chunks)
{
	int reserved_chunks;
	int reserved_blocks = dev->param.n_reserved_blocks;
	int checkpt_blocks;

	checkpt_blocks = yaffs_calc_checkpt_blocks_required(dev);

	reserved_chunks =
	    ((reserved_blocks + checkpt_blocks) * dev->param.chunks_per_block);

	return (dev->n_free_chunks > (reserved_chunks + n_chunks));
}

static int yaffs_find_alloc_block(struct yaffs_dev *dev)
{
	int i;

	struct yaffs_block_info *bi;

	if (dev->n_erased_blocks < 1) {
		yaffs_trace(YAFFS_TRACE_ERROR,
		  "yaffs tragedy: no more erased blocks" );

		return -1;
	}

	

	for (i = dev->internal_start_block; i <= dev->internal_end_block; i++) {
		dev->alloc_block_finder++;
		if (dev->alloc_block_finder < dev->internal_start_block
		    || dev->alloc_block_finder > dev->internal_end_block) {
			dev->alloc_block_finder = dev->internal_start_block;
		}

		bi = yaffs_get_block_info(dev, dev->alloc_block_finder);

		if (bi->block_state == YAFFS_BLOCK_STATE_EMPTY) {
			bi->block_state = YAFFS_BLOCK_STATE_ALLOCATING;
			dev->seq_number++;
			bi->seq_number = dev->seq_number;
			dev->n_erased_blocks--;
			yaffs_trace(YAFFS_TRACE_ALLOCATE,
			  "Allocated block %d, seq  %d, %d left" ,
			   dev->alloc_block_finder, dev->seq_number,
			   dev->n_erased_blocks);
			return dev->alloc_block_finder;
		}
	}

	yaffs_trace(YAFFS_TRACE_ALWAYS,
		"yaffs tragedy: no more erased blocks, but there should have been %d",
		dev->n_erased_blocks);

	return -1;
}

static int yaffs_alloc_chunk(struct yaffs_dev *dev, int use_reserver,
			     struct yaffs_block_info **block_ptr)
{
	int ret_val;
	struct yaffs_block_info *bi;

	if (dev->alloc_block < 0) {
		
		dev->alloc_block = yaffs_find_alloc_block(dev);
		dev->alloc_page = 0;
	}

	if (!use_reserver && !yaffs_check_alloc_available(dev, 1)) {
		
		return -1;
	}

	if (dev->n_erased_blocks < dev->param.n_reserved_blocks
	    && dev->alloc_page == 0)
		yaffs_trace(YAFFS_TRACE_ALLOCATE, "Allocating reserve");

	
	if (dev->alloc_block >= 0) {
		bi = yaffs_get_block_info(dev, dev->alloc_block);

		ret_val = (dev->alloc_block * dev->param.chunks_per_block) +
		    dev->alloc_page;
		bi->pages_in_use++;
		yaffs_set_chunk_bit(dev, dev->alloc_block, dev->alloc_page);

		dev->alloc_page++;

		dev->n_free_chunks--;

		
		if (dev->alloc_page >= dev->param.chunks_per_block) {
			bi->block_state = YAFFS_BLOCK_STATE_FULL;
			dev->alloc_block = -1;
		}

		if (block_ptr)
			*block_ptr = bi;

		return ret_val;
	}

	yaffs_trace(YAFFS_TRACE_ERROR, "!!!!!!!!! Allocator out !!!!!!!!!!!!!!!!!" );

	return -1;
}

static int yaffs_get_erased_chunks(struct yaffs_dev *dev)
{
	int n;

	n = dev->n_erased_blocks * dev->param.chunks_per_block;

	if (dev->alloc_block > 0)
		n += (dev->param.chunks_per_block - dev->alloc_page);

	return n;

}

void yaffs_skip_rest_of_block(struct yaffs_dev *dev)
{
	if (dev->alloc_block > 0) {
		struct yaffs_block_info *bi =
		    yaffs_get_block_info(dev, dev->alloc_block);
		if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING) {
			bi->block_state = YAFFS_BLOCK_STATE_FULL;
			dev->alloc_block = -1;
		}
	}
}

static int yaffs_write_new_chunk(struct yaffs_dev *dev,
				 const u8 * data,
				 struct yaffs_ext_tags *tags, int use_reserver)
{
	int attempts = 0;
	int write_ok = 0;
	int chunk;

	yaffs2_checkpt_invalidate(dev);

	do {
		struct yaffs_block_info *bi = 0;
		int erased_ok = 0;

		chunk = yaffs_alloc_chunk(dev, use_reserver, &bi);
		if (chunk < 0) {
			
			break;
		}

		/* First check this chunk is erased, if it needs
		 * checking.  The checking policy (unless forced
		 * always on) is as follows:
		 *
		 * Check the first page we try to write in a block.
		 * If the check passes then we don't need to check any
		 * more.        If the check fails, we check again...
		 * If the block has been erased, we don't need to check.
		 *
		 * However, if the block has been prioritised for gc,
		 * then we think there might be something odd about
		 * this block and stop using it.
		 *
		 * Rationale: We should only ever see chunks that have
		 * not been erased if there was a partially written
		 * chunk due to power loss.  This checking policy should
		 * catch that case with very few checks and thus save a
		 * lot of checks that are most likely not needed.
		 *
		 * Mods to the above
		 * If an erase check fails or the write fails we skip the 
		 * rest of the block.
		 */

		
		attempts++;

		if (dev->param.always_check_erased)
			bi->skip_erased_check = 0;

		if (!bi->skip_erased_check) {
			erased_ok = yaffs_check_chunk_erased(dev, chunk);
			if (erased_ok != YAFFS_OK) {
				yaffs_trace(YAFFS_TRACE_ERROR,
				  "**>> yaffs chunk %d was not erased",
				  chunk);

				yaffs_chunk_del(dev, chunk, 1, __LINE__);
				yaffs_skip_rest_of_block(dev);
				continue;
			}
		}

		write_ok = yaffs_wr_chunk_tags_nand(dev, chunk, data, tags);

		if (!bi->skip_erased_check)
			write_ok =
			    yaffs_verify_chunk_written(dev, chunk, data, tags);

		if (write_ok != YAFFS_OK) {
			yaffs_handle_chunk_wr_error(dev, chunk, erased_ok);
			continue;
		}

		bi->skip_erased_check = 1;

		
		yaffs_handle_chunk_wr_ok(dev, chunk, data, tags);

	} while (write_ok != YAFFS_OK &&
		 (yaffs_wr_attempts <= 0 || attempts <= yaffs_wr_attempts));

	if (!write_ok)
		chunk = -1;

	if (attempts > 1) {
		yaffs_trace(YAFFS_TRACE_ERROR,
			"**>> yaffs write required %d attempts",
			attempts);
		dev->n_retired_writes += (attempts - 1);
	}

	return chunk;
}


static void yaffs_retire_block(struct yaffs_dev *dev, int flash_block)
{
	struct yaffs_block_info *bi = yaffs_get_block_info(dev, flash_block);

	yaffs2_checkpt_invalidate(dev);

	yaffs2_clear_oldest_dirty_seq(dev, bi);

	if (yaffs_mark_bad(dev, flash_block) != YAFFS_OK) {
		if (yaffs_erase_block(dev, flash_block) != YAFFS_OK) {
			yaffs_trace(YAFFS_TRACE_ALWAYS,
				"yaffs: Failed to mark bad and erase block %d",
				flash_block);
		} else {
			struct yaffs_ext_tags tags;
			int chunk_id =
			    flash_block * dev->param.chunks_per_block;

			u8 *buffer = yaffs_get_temp_buffer(dev, __LINE__);

			memset(buffer, 0xff, dev->data_bytes_per_chunk);
			yaffs_init_tags(&tags);
			tags.seq_number = YAFFS_SEQUENCE_BAD_BLOCK;
			if (dev->param.write_chunk_tags_fn(dev, chunk_id -
							   dev->chunk_offset,
							   buffer,
							   &tags) != YAFFS_OK)
				yaffs_trace(YAFFS_TRACE_ALWAYS,
					"yaffs: Failed to write bad block marker to block %d",
					flash_block);

			yaffs_release_temp_buffer(dev, buffer, __LINE__);
		}
	}

	bi->block_state = YAFFS_BLOCK_STATE_DEAD;
	bi->gc_prioritise = 0;
	bi->needs_retiring = 0;

	dev->n_retired_blocks++;
}


static u16 yaffs_calc_name_sum(const YCHAR * name)
{
	u16 sum = 0;
	u16 i = 1;

	const YUCHAR *bname = (const YUCHAR *)name;
	if (bname) {
		while ((*bname) && (i < (YAFFS_MAX_NAME_LENGTH / 2))) {

			
			sum += ((*bname) & 0x1f) * i;
			i++;
			bname++;
		}
	}
	return sum;
}

void yaffs_set_obj_name(struct yaffs_obj *obj, const YCHAR * name)
{
#ifndef CONFIG_YAFFS_NO_SHORT_NAMES
	memset(obj->short_name, 0, sizeof(obj->short_name));
	if (name && 
	        strnlen(name, YAFFS_SHORT_NAME_LENGTH + 1) <=
	    YAFFS_SHORT_NAME_LENGTH)
		strcpy(obj->short_name, name);
	else
		obj->short_name[0] = _Y('\0');
#endif
	obj->sum = yaffs_calc_name_sum(name);
}

void yaffs_set_obj_name_from_oh(struct yaffs_obj *obj,
				const struct yaffs_obj_hdr *oh)
{
#ifdef CONFIG_YAFFS_AUTO_UNICODE
	YCHAR tmp_name[YAFFS_MAX_NAME_LENGTH + 1];
	memset(tmp_name, 0, sizeof(tmp_name));
	yaffs_load_name_from_oh(obj->my_dev, tmp_name, oh->name,
				YAFFS_MAX_NAME_LENGTH + 1);
	yaffs_set_obj_name(obj, tmp_name);
#else
	yaffs_set_obj_name(obj, oh->name);
#endif
}


struct yaffs_tnode *yaffs_get_tnode(struct yaffs_dev *dev)
{
	struct yaffs_tnode *tn = yaffs_alloc_raw_tnode(dev);
	if (tn) {
		memset(tn, 0, dev->tnode_size);
		dev->n_tnodes++;
	}

	dev->checkpoint_blocks_required = 0;	

	return tn;
}

static void yaffs_free_tnode(struct yaffs_dev *dev, struct yaffs_tnode *tn)
{
	yaffs_free_raw_tnode(dev, tn);
	dev->n_tnodes--;
	dev->checkpoint_blocks_required = 0;	
}

static void yaffs_deinit_tnodes_and_objs(struct yaffs_dev *dev)
{
	yaffs_deinit_raw_tnodes_and_objs(dev);
	dev->n_obj = 0;
	dev->n_tnodes = 0;
}

void yaffs_load_tnode_0(struct yaffs_dev *dev, struct yaffs_tnode *tn,
			unsigned pos, unsigned val)
{
	u32 *map = (u32 *) tn;
	u32 bit_in_map;
	u32 bit_in_word;
	u32 word_in_map;
	u32 mask;

	pos &= YAFFS_TNODES_LEVEL0_MASK;
	val >>= dev->chunk_grp_bits;

	bit_in_map = pos * dev->tnode_width;
	word_in_map = bit_in_map / 32;
	bit_in_word = bit_in_map & (32 - 1);

	mask = dev->tnode_mask << bit_in_word;

	map[word_in_map] &= ~mask;
	map[word_in_map] |= (mask & (val << bit_in_word));

	if (dev->tnode_width > (32 - bit_in_word)) {
		bit_in_word = (32 - bit_in_word);
		word_in_map++;;
		mask =
		    dev->tnode_mask >> (  bit_in_word);
		map[word_in_map] &= ~mask;
		map[word_in_map] |= (mask & (val >> bit_in_word));
	}
}

u32 yaffs_get_group_base(struct yaffs_dev *dev, struct yaffs_tnode *tn,
			 unsigned pos)
{
	u32 *map = (u32 *) tn;
	u32 bit_in_map;
	u32 bit_in_word;
	u32 word_in_map;
	u32 val;

	pos &= YAFFS_TNODES_LEVEL0_MASK;

	bit_in_map = pos * dev->tnode_width;
	word_in_map = bit_in_map / 32;
	bit_in_word = bit_in_map & (32 - 1);

	val = map[word_in_map] >> bit_in_word;

	if (dev->tnode_width > (32 - bit_in_word)) {
		bit_in_word = (32 - bit_in_word);
		word_in_map++;;
		val |= (map[word_in_map] << bit_in_word);
	}

	val &= dev->tnode_mask;
	val <<= dev->chunk_grp_bits;

	return val;
}



struct yaffs_tnode *yaffs_find_tnode_0(struct yaffs_dev *dev,
				       struct yaffs_file_var *file_struct,
				       u32 chunk_id)
{
	struct yaffs_tnode *tn = file_struct->top;
	u32 i;
	int required_depth;
	int level = file_struct->top_level;

	dev = dev;

	
	if (level < 0 || level > YAFFS_TNODES_MAX_LEVEL)
		return NULL;

	if (chunk_id > YAFFS_MAX_CHUNK_ID)
		return NULL;

	

	i = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
	required_depth = 0;
	while (i) {
		i >>= YAFFS_TNODES_INTERNAL_BITS;
		required_depth++;
	}

	if (required_depth > file_struct->top_level)
		return NULL;	

	
	while (level > 0 && tn) {
		tn = tn->internal[(chunk_id >>
				   (YAFFS_TNODES_LEVEL0_BITS +
				    (level - 1) *
				    YAFFS_TNODES_INTERNAL_BITS)) &
				  YAFFS_TNODES_INTERNAL_MASK];
		level--;
	}

	return tn;
}


struct yaffs_tnode *yaffs_add_find_tnode_0(struct yaffs_dev *dev,
					   struct yaffs_file_var *file_struct,
					   u32 chunk_id,
					   struct yaffs_tnode *passed_tn)
{
	int required_depth;
	int i;
	int l;
	struct yaffs_tnode *tn;

	u32 x;

	
	if (file_struct->top_level < 0
	    || file_struct->top_level > YAFFS_TNODES_MAX_LEVEL)
		return NULL;

	if (chunk_id > YAFFS_MAX_CHUNK_ID)
		return NULL;

	

	x = chunk_id >> YAFFS_TNODES_LEVEL0_BITS;
	required_depth = 0;
	while (x) {
		x >>= YAFFS_TNODES_INTERNAL_BITS;
		required_depth++;
	}

	if (required_depth > file_struct->top_level) {
		
		for (i = file_struct->top_level; i < required_depth; i++) {

			tn = yaffs_get_tnode(dev);

			if (tn) {
				tn->internal[0] = file_struct->top;
				file_struct->top = tn;
				file_struct->top_level++;
			} else {
				yaffs_trace(YAFFS_TRACE_ERROR, "yaffs: no more tnodes");
				return NULL;
			}
		}
	}

	

	l = file_struct->top_level;
	tn = file_struct->top;

	if (l > 0) {
		while (l > 0 && tn) {
			x = (chunk_id >>
			     (YAFFS_TNODES_LEVEL0_BITS +
			      (l - 1) * YAFFS_TNODES_INTERNAL_BITS)) &
			    YAFFS_TNODES_INTERNAL_MASK;

			if ((l > 1) && !tn->internal[x]) {
				
				tn->internal[x] = yaffs_get_tnode(dev);
				if (!tn->internal[x])
					return NULL;
			} else if (l == 1) {
				
				if (passed_tn) {
					
					if (tn->internal[x])
						yaffs_free_tnode(dev,
								 tn->
								 internal[x]);
					tn->internal[x] = passed_tn;

				} else if (!tn->internal[x]) {
					
					tn->internal[x] = yaffs_get_tnode(dev);
					if (!tn->internal[x])
						return NULL;
				}
			}

			tn = tn->internal[x];
			l--;
		}
	} else {
		
		if (passed_tn) {
			memcpy(tn, passed_tn,
			       (dev->tnode_width * YAFFS_NTNODES_LEVEL0) / 8);
			yaffs_free_tnode(dev, passed_tn);
		}
	}

	return tn;
}

static int yaffs_tags_match(const struct yaffs_ext_tags *tags, int obj_id,
			    int chunk_obj)
{
	return (tags->chunk_id == chunk_obj &&
		tags->obj_id == obj_id && !tags->is_deleted) ? 1 : 0;

}

static int yaffs_find_chunk_in_group(struct yaffs_dev *dev, int the_chunk,
				     struct yaffs_ext_tags *tags, int obj_id,
				     int inode_chunk)
{
	int j;

	for (j = 0; the_chunk && j < dev->chunk_grp_size; j++) {
		if (yaffs_check_chunk_bit
		    (dev, the_chunk / dev->param.chunks_per_block,
		     the_chunk % dev->param.chunks_per_block)) {

			if (dev->chunk_grp_size == 1)
				return the_chunk;
			else {
				yaffs_rd_chunk_tags_nand(dev, the_chunk, NULL,
							 tags);
				if (yaffs_tags_match(tags, obj_id, inode_chunk)) {
					
					return the_chunk;
				}
			}
		}
		the_chunk++;
	}
	return -1;
}

static int yaffs_find_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
				    struct yaffs_ext_tags *tags)
{
	
	struct yaffs_tnode *tn;
	int the_chunk = -1;
	struct yaffs_ext_tags local_tags;
	int ret_val = -1;

	struct yaffs_dev *dev = in->my_dev;

	if (!tags) {
		
		tags = &local_tags;
	}

	tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);

	if (tn) {
		the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);

		ret_val =
		    yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
					      inode_chunk);
	}
	return ret_val;
}

static int yaffs_find_del_file_chunk(struct yaffs_obj *in, int inode_chunk,
				     struct yaffs_ext_tags *tags)
{
	
	struct yaffs_tnode *tn;
	int the_chunk = -1;
	struct yaffs_ext_tags local_tags;

	struct yaffs_dev *dev = in->my_dev;
	int ret_val = -1;

	if (!tags) {
		
		tags = &local_tags;
	}

	tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);

	if (tn) {

		the_chunk = yaffs_get_group_base(dev, tn, inode_chunk);

		ret_val =
		    yaffs_find_chunk_in_group(dev, the_chunk, tags, in->obj_id,
					      inode_chunk);

		
		if (ret_val != -1)
			yaffs_load_tnode_0(dev, tn, inode_chunk, 0);
	}

	return ret_val;
}

int yaffs_put_chunk_in_file(struct yaffs_obj *in, int inode_chunk,
			    int nand_chunk, int in_scan)
{

	struct yaffs_tnode *tn;
	struct yaffs_dev *dev = in->my_dev;
	int existing_cunk;
	struct yaffs_ext_tags existing_tags;
	struct yaffs_ext_tags new_tags;
	unsigned existing_serial, new_serial;

	if (in->variant_type != YAFFS_OBJECT_TYPE_FILE) {
		if (!in_scan) {
			yaffs_trace(YAFFS_TRACE_ERROR,
				"yaffs tragedy:attempt to put data chunk into a non-file"
				);
			YBUG();
		}

		yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
		return YAFFS_OK;
	}

	tn = yaffs_add_find_tnode_0(dev,
				    &in->variant.file_variant,
				    inode_chunk, NULL);
	if (!tn)
		return YAFFS_FAIL;

	if (!nand_chunk)
		
		return YAFFS_OK;

	existing_cunk = yaffs_get_group_base(dev, tn, inode_chunk);

	if (in_scan != 0) {

		if (existing_cunk > 0) {

			if (in_scan > 0) {
				
				yaffs_rd_chunk_tags_nand(dev,
							 nand_chunk,
							 NULL, &new_tags);

				
				existing_cunk =
				    yaffs_find_chunk_in_file(in, inode_chunk,
							     &existing_tags);
			}

			if (existing_cunk <= 0) {
				

				yaffs_trace(YAFFS_TRACE_ERROR,
					"yaffs tragedy: existing chunk < 0 in scan"
					);

			}


			if (in_scan > 0) {
				new_serial = new_tags.serial_number;
				existing_serial = existing_tags.serial_number;
			}

			if ((in_scan > 0) &&
			    (existing_cunk <= 0 ||
			     ((existing_serial + 1) & 3) == new_serial)) {
				yaffs_chunk_del(dev, existing_cunk, 1,
						__LINE__);
			} else {
				yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
				return YAFFS_OK;
			}
		}

	}

	if (existing_cunk == 0)
		in->n_data_chunks++;

	yaffs_load_tnode_0(dev, tn, inode_chunk, nand_chunk);

	return YAFFS_OK;
}

static void yaffs_soft_del_chunk(struct yaffs_dev *dev, int chunk)
{
	struct yaffs_block_info *the_block;
	unsigned block_no;

	yaffs_trace(YAFFS_TRACE_DELETION, "soft delete chunk %d", chunk);

	block_no = chunk / dev->param.chunks_per_block;
	the_block = yaffs_get_block_info(dev, block_no);
	if (the_block) {
		the_block->soft_del_pages++;
		dev->n_free_chunks++;
		yaffs2_update_oldest_dirty_seq(dev, block_no, the_block);
	}
}


static int yaffs_soft_del_worker(struct yaffs_obj *in, struct yaffs_tnode *tn,
				 u32 level, int chunk_offset)
{
	int i;
	int the_chunk;
	int all_done = 1;
	struct yaffs_dev *dev = in->my_dev;

	if (tn) {
		if (level > 0) {

			for (i = YAFFS_NTNODES_INTERNAL - 1; all_done && i >= 0;
			     i--) {
				if (tn->internal[i]) {
					all_done =
					    yaffs_soft_del_worker(in,
								  tn->internal
								  [i],
								  level - 1,
								  (chunk_offset
								   <<
								   YAFFS_TNODES_INTERNAL_BITS)
								  + i);
					if (all_done) {
						yaffs_free_tnode(dev,
								 tn->internal
								 [i]);
						tn->internal[i] = NULL;
					} else {
						
					}
				}
			}
			return (all_done) ? 1 : 0;
		} else if (level == 0) {

			for (i = YAFFS_NTNODES_LEVEL0 - 1; i >= 0; i--) {
				the_chunk = yaffs_get_group_base(dev, tn, i);
				if (the_chunk) {
					yaffs_soft_del_chunk(dev, the_chunk);
					yaffs_load_tnode_0(dev, tn, i, 0);
				}

			}
			return 1;

		}

	}

	return 1;

}

static void yaffs_remove_obj_from_dir(struct yaffs_obj *obj)
{
	struct yaffs_dev *dev = obj->my_dev;
	struct yaffs_obj *parent;

	yaffs_verify_obj_in_dir(obj);
	parent = obj->parent;

	yaffs_verify_dir(parent);

	if (dev && dev->param.remove_obj_fn)
		dev->param.remove_obj_fn(obj);

	list_del_init(&obj->siblings);
	obj->parent = NULL;

	yaffs_verify_dir(parent);
}

void yaffs_add_obj_to_dir(struct yaffs_obj *directory, struct yaffs_obj *obj)
{
	if (!directory) {
		yaffs_trace(YAFFS_TRACE_ALWAYS,
			"tragedy: Trying to add an object to a null pointer directory"
			);
		YBUG();
		return;
	}
	if (directory->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
		yaffs_trace(YAFFS_TRACE_ALWAYS,
			"tragedy: Trying to add an object to a non-directory"
			);
		YBUG();
	}

	if (obj->siblings.prev == NULL) {
		
		YBUG();
	}

	yaffs_verify_dir(directory);

	yaffs_remove_obj_from_dir(obj);

	
	list_add(&obj->siblings, &directory->variant.dir_variant.children);
	obj->parent = directory;

	if (directory == obj->my_dev->unlinked_dir
	    || directory == obj->my_dev->del_dir) {
		obj->unlinked = 1;
		obj->my_dev->n_unlinked_files++;
		obj->rename_allowed = 0;
	}

	yaffs_verify_dir(directory);
	yaffs_verify_obj_in_dir(obj);
}

static int yaffs_change_obj_name(struct yaffs_obj *obj,
				 struct yaffs_obj *new_dir,
				 const YCHAR * new_name, int force, int shadows)
{
	int unlink_op;
	int del_op;

	struct yaffs_obj *existing_target;

	if (new_dir == NULL)
		new_dir = obj->parent;	

	if (new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
		yaffs_trace(YAFFS_TRACE_ALWAYS,
			"tragedy: yaffs_change_obj_name: new_dir is not a directory"
			);
		YBUG();
	}

	
	if (obj->my_dev->param.is_yaffs2)
		unlink_op = (new_dir == obj->my_dev->unlinked_dir);
	else
		unlink_op = (new_dir == obj->my_dev->unlinked_dir
			     && obj->variant_type == YAFFS_OBJECT_TYPE_FILE);

	del_op = (new_dir == obj->my_dev->del_dir);

	existing_target = yaffs_find_by_name(new_dir, new_name);

	if ((unlink_op ||
	     del_op ||
	     force ||
	     (shadows > 0) ||
	     !existing_target) &&
	    new_dir->variant_type == YAFFS_OBJECT_TYPE_DIRECTORY) {
		yaffs_set_obj_name(obj, new_name);
		obj->dirty = 1;

		yaffs_add_obj_to_dir(new_dir, obj);

		if (unlink_op)
			obj->unlinked = 1;

		
		if (yaffs_update_oh(obj, new_name, 0, del_op, shadows, NULL) >=
		    0)
			return YAFFS_OK;
	}

	return YAFFS_FAIL;
}


static int yaffs_obj_cache_dirty(struct yaffs_obj *obj)
{
	struct yaffs_dev *dev = obj->my_dev;
	int i;
	struct yaffs_cache *cache;
	int n_caches = obj->my_dev->param.n_caches;

	for (i = 0; i < n_caches; i++) {
		cache = &dev->cache[i];
		if (cache->object == obj && cache->dirty)
			return 1;
	}

	return 0;
}

static void yaffs_flush_file_cache(struct yaffs_obj *obj)
{
	struct yaffs_dev *dev = obj->my_dev;
	int lowest = -99;	
	int i;
	struct yaffs_cache *cache;
	int chunk_written = 0;
	int n_caches = obj->my_dev->param.n_caches;

	if (n_caches > 0) {
		do {
			cache = NULL;

			
			for (i = 0; i < n_caches; i++) {
				if (dev->cache[i].object == obj &&
				    dev->cache[i].dirty) {
					if (!cache
					    || dev->cache[i].chunk_id <
					    lowest) {
						cache = &dev->cache[i];
						lowest = cache->chunk_id;
					}
				}
			}

			if (cache && !cache->locked) {
				

				chunk_written =
				    yaffs_wr_data_obj(cache->object,
						      cache->chunk_id,
						      cache->data,
						      cache->n_bytes, 1);
				cache->dirty = 0;
				cache->object = NULL;
			}

		} while (cache && chunk_written > 0);

		if (cache)
			
			yaffs_trace(YAFFS_TRACE_ERROR,
				"yaffs tragedy: no space during cache write");

	}

}


void yaffs_flush_whole_cache(struct yaffs_dev *dev)
{
	struct yaffs_obj *obj;
	int n_caches = dev->param.n_caches;
	int i;

	do {
		obj = NULL;
		for (i = 0; i < n_caches && !obj; i++) {
			if (dev->cache[i].object && dev->cache[i].dirty)
				obj = dev->cache[i].object;

		}
		if (obj)
			yaffs_flush_file_cache(obj);

	} while (obj);

}

static struct yaffs_cache *yaffs_grab_chunk_worker(struct yaffs_dev *dev)
{
	int i;

	if (dev->param.n_caches > 0) {
		for (i = 0; i < dev->param.n_caches; i++) {
			if (!dev->cache[i].object)
				return &dev->cache[i];
		}
	}

	return NULL;
}

static struct yaffs_cache *yaffs_grab_chunk_cache(struct yaffs_dev *dev)
{
	struct yaffs_cache *cache;
	struct yaffs_obj *the_obj;
	int usage;
	int i;
	int pushout;

	if (dev->param.n_caches > 0) {
		

		cache = yaffs_grab_chunk_worker(dev);

		if (!cache) {

			

			the_obj = NULL;
			usage = -1;
			cache = NULL;
			pushout = -1;

			for (i = 0; i < dev->param.n_caches; i++) {
				if (dev->cache[i].object &&
				    !dev->cache[i].locked &&
				    (dev->cache[i].last_use < usage
				     || !cache)) {
					usage = dev->cache[i].last_use;
					the_obj = dev->cache[i].object;
					cache = &dev->cache[i];
					pushout = i;
				}
			}

			if (!cache || cache->dirty) {
				
				yaffs_flush_file_cache(the_obj);
				cache = yaffs_grab_chunk_worker(dev);
			}

		}
		return cache;
	} else {
		return NULL;
        }
}

static struct yaffs_cache *yaffs_find_chunk_cache(const struct yaffs_obj *obj,
						  int chunk_id)
{
	struct yaffs_dev *dev = obj->my_dev;
	int i;
	if (dev->param.n_caches > 0) {
		for (i = 0; i < dev->param.n_caches; i++) {
			if (dev->cache[i].object == obj &&
			    dev->cache[i].chunk_id == chunk_id) {
				dev->cache_hits++;

				return &dev->cache[i];
			}
		}
	}
	return NULL;
}

static void yaffs_use_cache(struct yaffs_dev *dev, struct yaffs_cache *cache,
			    int is_write)
{

	if (dev->param.n_caches > 0) {
		if (dev->cache_last_use < 0 || dev->cache_last_use > 100000000) {
			
			int i;
			for (i = 1; i < dev->param.n_caches; i++)
				dev->cache[i].last_use = 0;

			dev->cache_last_use = 0;
		}

		dev->cache_last_use++;

		cache->last_use = dev->cache_last_use;

		if (is_write)
			cache->dirty = 1;
	}
}

/* Invalidate a single cache page.
 * Do this when a whole page gets written,
 * ie the short cache for this page is no longer valid.
 */
static void yaffs_invalidate_chunk_cache(struct yaffs_obj *object, int chunk_id)
{
	if (object->my_dev->param.n_caches > 0) {
		struct yaffs_cache *cache =
		    yaffs_find_chunk_cache(object, chunk_id);

		if (cache)
			cache->object = NULL;
	}
}

static void yaffs_invalidate_whole_cache(struct yaffs_obj *in)
{
	int i;
	struct yaffs_dev *dev = in->my_dev;

	if (dev->param.n_caches > 0) {
		
		for (i = 0; i < dev->param.n_caches; i++) {
			if (dev->cache[i].object == in)
				dev->cache[i].object = NULL;
		}
	}
}

static void yaffs_unhash_obj(struct yaffs_obj *obj)
{
	int bucket;
	struct yaffs_dev *dev = obj->my_dev;

	
	if (!list_empty(&obj->hash_link)) {
		list_del_init(&obj->hash_link);
		bucket = yaffs_hash_fn(obj->obj_id);
		dev->obj_bucket[bucket].count--;
	}
}

static void yaffs_free_obj(struct yaffs_obj *obj)
{
	struct yaffs_dev *dev = obj->my_dev;

	yaffs_trace(YAFFS_TRACE_OS, "FreeObject %p inode %p",
		obj, obj->my_inode);

	if (!obj)
		YBUG();
	if (obj->parent)
		YBUG();
	if (!list_empty(&obj->siblings))
		YBUG();

	if (obj->my_inode) {
		obj->defered_free = 1;
		return;
	}

	yaffs_unhash_obj(obj);

	yaffs_free_raw_obj(dev, obj);
	dev->n_obj--;
	dev->checkpoint_blocks_required = 0;	
}

void yaffs_handle_defered_free(struct yaffs_obj *obj)
{
	if (obj->defered_free)
		yaffs_free_obj(obj);
}

static int yaffs_generic_obj_del(struct yaffs_obj *in)
{

	
	yaffs_invalidate_whole_cache(in);

	if (in->my_dev->param.is_yaffs2 && (in->parent != in->my_dev->del_dir)) {
		
		yaffs_change_obj_name(in, in->my_dev->del_dir, _Y("deleted"), 0,
				      0);

	}

	yaffs_remove_obj_from_dir(in);
	yaffs_chunk_del(in->my_dev, in->hdr_chunk, 1, __LINE__);
	in->hdr_chunk = 0;

	yaffs_free_obj(in);
	return YAFFS_OK;

}

static void yaffs_soft_del_file(struct yaffs_obj *obj)
{
	if (obj->deleted &&
	    obj->variant_type == YAFFS_OBJECT_TYPE_FILE && !obj->soft_del) {
		if (obj->n_data_chunks <= 0) {
			yaffs_free_tnode(obj->my_dev,
					 obj->variant.file_variant.top);
			obj->variant.file_variant.top = NULL;
			yaffs_trace(YAFFS_TRACE_TRACING,
				"yaffs: Deleting empty file %d",
				obj->obj_id);
			yaffs_generic_obj_del(obj);
		} else {
			yaffs_soft_del_worker(obj,
					      obj->variant.file_variant.top,
					      obj->variant.
					      file_variant.top_level, 0);
			obj->soft_del = 1;
		}
	}
}


static struct yaffs_tnode *yaffs_prune_worker(struct yaffs_dev *dev,
					      struct yaffs_tnode *tn, u32 level,
					      int del0)
{
	int i;
	int has_data;

	if (tn) {
		has_data = 0;

		if (level > 0) {
			for (i = 0; i < YAFFS_NTNODES_INTERNAL; i++) {
				if (tn->internal[i]) {
					tn->internal[i] =
					    yaffs_prune_worker(dev,
							       tn->internal[i],
							       level - 1,
							       (i ==
								0) ? del0 : 1);
				}

				if (tn->internal[i])
					has_data++;
			}
		} else {
			int tnode_size_u32 = dev->tnode_size / sizeof(u32);
			u32 *map = (u32 *) tn;

			for (i = 0; !has_data && i < tnode_size_u32; i++) {
				if (map[i])
					has_data++;
			}
		}

		if (has_data == 0 && del0) {
			

			yaffs_free_tnode(dev, tn);
			tn = NULL;
		}

	}

	return tn;

}

static int yaffs_prune_tree(struct yaffs_dev *dev,
			    struct yaffs_file_var *file_struct)
{
	int i;
	int has_data;
	int done = 0;
	struct yaffs_tnode *tn;

	if (file_struct->top_level > 0) {
		file_struct->top =
		    yaffs_prune_worker(dev, file_struct->top,
				       file_struct->top_level, 0);


		while (file_struct->top_level && !done) {
			tn = file_struct->top;

			has_data = 0;
			for (i = 1; i < YAFFS_NTNODES_INTERNAL; i++) {
				if (tn->internal[i])
					has_data++;
			}

			if (!has_data) {
				file_struct->top = tn->internal[0];
				file_struct->top_level--;
				yaffs_free_tnode(dev, tn);
			} else {
				done = 1;
			}
		}
	}

	return YAFFS_OK;
}


static struct yaffs_obj *yaffs_alloc_empty_obj(struct yaffs_dev *dev)
{
	struct yaffs_obj *obj = yaffs_alloc_raw_obj(dev);

	if (obj) {
		dev->n_obj++;

		

		memset(obj, 0, sizeof(struct yaffs_obj));
		obj->being_created = 1;

		obj->my_dev = dev;
		obj->hdr_chunk = 0;
		obj->variant_type = YAFFS_OBJECT_TYPE_UNKNOWN;
		INIT_LIST_HEAD(&(obj->hard_links));
		INIT_LIST_HEAD(&(obj->hash_link));
		INIT_LIST_HEAD(&obj->siblings);

		
		if (dev->root_dir) {
			obj->parent = dev->root_dir;
			list_add(&(obj->siblings),
				 &dev->root_dir->variant.dir_variant.children);
		}

		if (dev->lost_n_found)
			yaffs_add_obj_to_dir(dev->lost_n_found, obj);

		obj->being_created = 0;
	}

	dev->checkpoint_blocks_required = 0;	

	return obj;
}

static int yaffs_find_nice_bucket(struct yaffs_dev *dev)
{
	int i;
	int l = 999;
	int lowest = 999999;


	for (i = 0; i < 10 && lowest > 4; i++) {
		dev->bucket_finder++;
		dev->bucket_finder %= YAFFS_NOBJECT_BUCKETS;
		if (dev->obj_bucket[dev->bucket_finder].count < lowest) {
			lowest = dev->obj_bucket[dev->bucket_finder].count;
			l = dev->bucket_finder;
		}

	}

	return l;
}

static int yaffs_new_obj_id(struct yaffs_dev *dev)
{
	int bucket = yaffs_find_nice_bucket(dev);


	int found = 0;
	struct list_head *i;

	u32 n = (u32) bucket;

	

	while (!found) {
		found = 1;
		n += YAFFS_NOBJECT_BUCKETS;
		if (1 || dev->obj_bucket[bucket].count > 0) {
			list_for_each(i, &dev->obj_bucket[bucket].list) {
				
				if (i && list_entry(i, struct yaffs_obj,
						    hash_link)->obj_id == n) {
					found = 0;
				}
			}
		}
	}

	return n;
}

static void yaffs_hash_obj(struct yaffs_obj *in)
{
	int bucket = yaffs_hash_fn(in->obj_id);
	struct yaffs_dev *dev = in->my_dev;

	list_add(&in->hash_link, &dev->obj_bucket[bucket].list);
	dev->obj_bucket[bucket].count++;
}

struct yaffs_obj *yaffs_find_by_number(struct yaffs_dev *dev, u32 number)
{
	int bucket = yaffs_hash_fn(number);
	struct list_head *i;
	struct yaffs_obj *in;

	list_for_each(i, &dev->obj_bucket[bucket].list) {
		
		if (i) {
			in = list_entry(i, struct yaffs_obj, hash_link);
			if (in->obj_id == number) {

				
				if (in->defered_free)
					return NULL;

				return in;
			}
		}
	}

	return NULL;
}

struct yaffs_obj *yaffs_new_obj(struct yaffs_dev *dev, int number,
				enum yaffs_obj_type type)
{
	struct yaffs_obj *the_obj = NULL;
	struct yaffs_tnode *tn = NULL;

	if (number < 0)
		number = yaffs_new_obj_id(dev);

	if (type == YAFFS_OBJECT_TYPE_FILE) {
		tn = yaffs_get_tnode(dev);
		if (!tn)
			return NULL;
	}

	the_obj = yaffs_alloc_empty_obj(dev);
	if (!the_obj) {
		if (tn)
			yaffs_free_tnode(dev, tn);
		return NULL;
	}

	if (the_obj) {
		the_obj->fake = 0;
		the_obj->rename_allowed = 1;
		the_obj->unlink_allowed = 1;
		the_obj->obj_id = number;
		yaffs_hash_obj(the_obj);
		the_obj->variant_type = type;
		yaffs_load_current_time(the_obj, 1, 1);

		switch (type) {
		case YAFFS_OBJECT_TYPE_FILE:
			the_obj->variant.file_variant.file_size = 0;
			the_obj->variant.file_variant.scanned_size = 0;
			the_obj->variant.file_variant.shrink_size = ~0;	
			the_obj->variant.file_variant.top_level = 0;
			the_obj->variant.file_variant.top = tn;
			break;
		case YAFFS_OBJECT_TYPE_DIRECTORY:
			INIT_LIST_HEAD(&the_obj->variant.dir_variant.children);
			INIT_LIST_HEAD(&the_obj->variant.dir_variant.dirty);
			break;
		case YAFFS_OBJECT_TYPE_SYMLINK:
		case YAFFS_OBJECT_TYPE_HARDLINK:
		case YAFFS_OBJECT_TYPE_SPECIAL:
			
			break;
		case YAFFS_OBJECT_TYPE_UNKNOWN:
			
			break;
		}
	}

	return the_obj;
}

static struct yaffs_obj *yaffs_create_fake_dir(struct yaffs_dev *dev,
					       int number, u32 mode)
{

	struct yaffs_obj *obj =
	    yaffs_new_obj(dev, number, YAFFS_OBJECT_TYPE_DIRECTORY);
	if (obj) {
		obj->fake = 1;	
		obj->rename_allowed = 0;	
		obj->unlink_allowed = 0;	
		obj->deleted = 0;
		obj->unlinked = 0;
		obj->yst_mode = mode;
		obj->my_dev = dev;
		obj->hdr_chunk = 0;	
	}

	return obj;

}


static void yaffs_init_tnodes_and_objs(struct yaffs_dev *dev)
{
	int i;

	dev->n_obj = 0;
	dev->n_tnodes = 0;

	yaffs_init_raw_tnodes_and_objs(dev);

	for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
		INIT_LIST_HEAD(&dev->obj_bucket[i].list);
		dev->obj_bucket[i].count = 0;
	}
}

struct yaffs_obj *yaffs_find_or_create_by_number(struct yaffs_dev *dev,
						 int number,
						 enum yaffs_obj_type type)
{
	struct yaffs_obj *the_obj = NULL;

	if (number > 0)
		the_obj = yaffs_find_by_number(dev, number);

	if (!the_obj)
		the_obj = yaffs_new_obj(dev, number, type);

	return the_obj;

}

YCHAR *yaffs_clone_str(const YCHAR * str)
{
	YCHAR *new_str = NULL;
	int len;

	if (!str)
		str = _Y("");

	len = strnlen(str, YAFFS_MAX_ALIAS_LENGTH);
	new_str = kmalloc((len + 1) * sizeof(YCHAR), GFP_NOFS);
	if (new_str) {
		strncpy(new_str, str, len);
		new_str[len] = 0;
	}
	return new_str;

}

static void yaffs_update_parent(struct yaffs_obj *obj)
{
	struct yaffs_dev *dev;
	if (!obj)
		return;
	dev = obj->my_dev;
	obj->dirty = 1;
	yaffs_load_current_time(obj, 0, 1);
	if (dev->param.defered_dir_update) {
		struct list_head *link = &obj->variant.dir_variant.dirty;

		if (list_empty(link)) {
			list_add(link, &dev->dirty_dirs);
			yaffs_trace(YAFFS_TRACE_BACKGROUND,
			  "Added object %d to dirty directories",
			   obj->obj_id);
		}

	} else {
		yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
        }
}

void yaffs_update_dirty_dirs(struct yaffs_dev *dev)
{
	struct list_head *link;
	struct yaffs_obj *obj;
	struct yaffs_dir_var *d_s;
	union yaffs_obj_var *o_v;

	yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update dirty directories");

	while (!list_empty(&dev->dirty_dirs)) {
		link = dev->dirty_dirs.next;
		list_del_init(link);

		d_s = list_entry(link, struct yaffs_dir_var, dirty);
		o_v = list_entry(d_s, union yaffs_obj_var, dir_variant);
		obj = list_entry(o_v, struct yaffs_obj, variant);

		yaffs_trace(YAFFS_TRACE_BACKGROUND, "Update directory %d",
			obj->obj_id);

		if (obj->dirty)
			yaffs_update_oh(obj, NULL, 0, 0, 0, NULL);
	}
}


static struct yaffs_obj *yaffs_create_obj(enum yaffs_obj_type type,
					  struct yaffs_obj *parent,
					  const YCHAR * name,
					  u32 mode,
					  u32 uid,
					  u32 gid,
					  struct yaffs_obj *equiv_obj,
					  const YCHAR * alias_str, u32 rdev)
{
	struct yaffs_obj *in;
	YCHAR *str = NULL;

	struct yaffs_dev *dev = parent->my_dev;

	
	if (yaffs_find_by_name(parent, name))
		return NULL;

	if (type == YAFFS_OBJECT_TYPE_SYMLINK) {
		str = yaffs_clone_str(alias_str);
		if (!str)
			return NULL;
	}

	in = yaffs_new_obj(dev, -1, type);

	if (!in) {
		if (str)
			kfree(str);
		return NULL;
	}

	if (in) {
		in->hdr_chunk = 0;
		in->valid = 1;
		in->variant_type = type;

		in->yst_mode = mode;

		yaffs_attribs_init(in, gid, uid, rdev);

		in->n_data_chunks = 0;

		yaffs_set_obj_name(in, name);
		in->dirty = 1;

		yaffs_add_obj_to_dir(parent, in);

		in->my_dev = parent->my_dev;

		switch (type) {
		case YAFFS_OBJECT_TYPE_SYMLINK:
			in->variant.symlink_variant.alias = str;
			break;
		case YAFFS_OBJECT_TYPE_HARDLINK:
			in->variant.hardlink_variant.equiv_obj = equiv_obj;
			in->variant.hardlink_variant.equiv_id =
			    equiv_obj->obj_id;
			list_add(&in->hard_links, &equiv_obj->hard_links);
			break;
		case YAFFS_OBJECT_TYPE_FILE:
		case YAFFS_OBJECT_TYPE_DIRECTORY:
		case YAFFS_OBJECT_TYPE_SPECIAL:
		case YAFFS_OBJECT_TYPE_UNKNOWN:
			
			break;
		}

		if (yaffs_update_oh(in, name, 0, 0, 0, NULL) < 0) {
			
			yaffs_del_obj(in);
			in = NULL;
		}

		yaffs_update_parent(parent);
	}

	return in;
}

struct yaffs_obj *yaffs_create_file(struct yaffs_obj *parent,
				    const YCHAR * name, u32 mode, u32 uid,
				    u32 gid)
{
	return yaffs_create_obj(YAFFS_OBJECT_TYPE_FILE, parent, name, mode,
				uid, gid, NULL, NULL, 0);
}

struct yaffs_obj *yaffs_create_dir(struct yaffs_obj *parent, const YCHAR * name,
				   u32 mode, u32 uid, u32 gid)
{
	return yaffs_create_obj(YAFFS_OBJECT_TYPE_DIRECTORY, parent, name,
				mode, uid, gid, NULL, NULL, 0);
}

struct yaffs_obj *yaffs_create_special(struct yaffs_obj *parent,
				       const YCHAR * name, u32 mode, u32 uid,
				       u32 gid, u32 rdev)
{
	return yaffs_create_obj(YAFFS_OBJECT_TYPE_SPECIAL, parent, name, mode,
				uid, gid, NULL, NULL, rdev);
}

struct yaffs_obj *yaffs_create_symlink(struct yaffs_obj *parent,
				       const YCHAR * name, u32 mode, u32 uid,
				       u32 gid, const YCHAR * alias)
{
	return yaffs_create_obj(YAFFS_OBJECT_TYPE_SYMLINK, parent, name, mode,
				uid, gid, NULL, alias, 0);
}

struct yaffs_obj *yaffs_link_obj(struct yaffs_obj *parent, const YCHAR * name,
				 struct yaffs_obj *equiv_obj)
{
	
	equiv_obj = yaffs_get_equivalent_obj(equiv_obj);

	if (yaffs_create_obj
	    (YAFFS_OBJECT_TYPE_HARDLINK, parent, name, 0, 0, 0,
	     equiv_obj, NULL, 0)) {
		return equiv_obj;
	} else {
		return NULL;
	}

}




static int yaffs_init_blocks(struct yaffs_dev *dev)
{
	int n_blocks = dev->internal_end_block - dev->internal_start_block + 1;

	dev->block_info = NULL;
	dev->chunk_bits = NULL;

	dev->alloc_block = -1;	

	
	dev->block_info =
		kmalloc(n_blocks * sizeof(struct yaffs_block_info), GFP_NOFS);
	if (!dev->block_info) {
		dev->block_info =
		    vmalloc(n_blocks * sizeof(struct yaffs_block_info));
		dev->block_info_alt = 1;
	} else {
		dev->block_info_alt = 0;
        }

	if (dev->block_info) {
		
		dev->chunk_bit_stride = (dev->param.chunks_per_block + 7) / 8;
		dev->chunk_bits =
			kmalloc(dev->chunk_bit_stride * n_blocks, GFP_NOFS);
		if (!dev->chunk_bits) {
			dev->chunk_bits =
			    vmalloc(dev->chunk_bit_stride * n_blocks);
			dev->chunk_bits_alt = 1;
		} else {
			dev->chunk_bits_alt = 0;
                }
	}

	if (dev->block_info && dev->chunk_bits) {
		memset(dev->block_info, 0,
		       n_blocks * sizeof(struct yaffs_block_info));
		memset(dev->chunk_bits, 0, dev->chunk_bit_stride * n_blocks);
		return YAFFS_OK;
	}

	return YAFFS_FAIL;
}

static void yaffs_deinit_blocks(struct yaffs_dev *dev)
{
	if (dev->block_info_alt && dev->block_info)
		vfree(dev->block_info);
	else if (dev->block_info)
		kfree(dev->block_info);

	dev->block_info_alt = 0;

	dev->block_info = NULL;

	if (dev->chunk_bits_alt && dev->chunk_bits)
		vfree(dev->chunk_bits);
	else if (dev->chunk_bits)
		kfree(dev->chunk_bits);
	dev->chunk_bits_alt = 0;
	dev->chunk_bits = NULL;
}

void yaffs_block_became_dirty(struct yaffs_dev *dev, int block_no)
{
	struct yaffs_block_info *bi = yaffs_get_block_info(dev, block_no);

	int erased_ok = 0;


	yaffs_trace(YAFFS_TRACE_GC | YAFFS_TRACE_ERASE,
		"yaffs_block_became_dirty block %d state %d %s",
		block_no, bi->block_state,
		(bi->needs_retiring) ? "needs retiring" : "");

	yaffs2_clear_oldest_dirty_seq(dev, bi);

	bi->block_state = YAFFS_BLOCK_STATE_DIRTY;

	
	if (block_no == dev->gc_block)
		dev->gc_block = 0;

	
	if (block_no == dev->gc_dirtiest) {
		dev->gc_dirtiest = 0;
		dev->gc_pages_in_use = 0;
	}

	if (!bi->needs_retiring) {
		yaffs2_checkpt_invalidate(dev);
		erased_ok = yaffs_erase_block(dev, block_no);
		if (!erased_ok) {
			dev->n_erase_failures++;
			yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
			  "**>> Erasure failed %d", block_no);
		}
	}

	if (erased_ok &&
	    ((yaffs_trace_mask & YAFFS_TRACE_ERASE)
	     || !yaffs_skip_verification(dev))) {
		int i;
		for (i = 0; i < dev->param.chunks_per_block; i++) {
			if (!yaffs_check_chunk_erased
			    (dev, block_no * dev->param.chunks_per_block + i)) {
				yaffs_trace(YAFFS_TRACE_ERROR,
					">>Block %d erasure supposedly OK, but chunk %d not erased",
					block_no, i);
			}
		}
	}

	if (erased_ok) {
		
		bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
		bi->seq_number = 0;
		dev->n_erased_blocks++;
		bi->pages_in_use = 0;
		bi->soft_del_pages = 0;
		bi->has_shrink_hdr = 0;
		bi->skip_erased_check = 1;	
		bi->gc_prioritise = 0;
		yaffs_clear_chunk_bits(dev, block_no);

		yaffs_trace(YAFFS_TRACE_ERASE,
			"Erased block %d", block_no);
	} else {
		
		dev->n_free_chunks -= dev->param.chunks_per_block;
		yaffs_retire_block(dev, block_no);
		yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
			"**>> Block %d retired", block_no);
	}
}



static int yaffs_gc_block(struct yaffs_dev *dev, int block, int whole_block)
{
	int old_chunk;
	int new_chunk;
	int mark_flash;
	int ret_val = YAFFS_OK;
	int i;
	int is_checkpt_block;
	int matching_chunk;
	int max_copies;

	int chunks_before = yaffs_get_erased_chunks(dev);
	int chunks_after;

	struct yaffs_ext_tags tags;

	struct yaffs_block_info *bi = yaffs_get_block_info(dev, block);

	struct yaffs_obj *object;

	is_checkpt_block = (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT);

	yaffs_trace(YAFFS_TRACE_TRACING,
		"Collecting block %d, in use %d, shrink %d, whole_block %d",
		block, bi->pages_in_use, bi->has_shrink_hdr,
		whole_block);

	

	if (bi->block_state == YAFFS_BLOCK_STATE_FULL)
		bi->block_state = YAFFS_BLOCK_STATE_COLLECTING;

	bi->has_shrink_hdr = 0;	

	dev->gc_disable = 1;

	if (is_checkpt_block || !yaffs_still_some_chunks(dev, block)) {
		yaffs_trace(YAFFS_TRACE_TRACING,
			"Collecting block %d that has no chunks in use",
		   	block);
		yaffs_block_became_dirty(dev, block);
	} else {

		u8 *buffer = yaffs_get_temp_buffer(dev, __LINE__);

		yaffs_verify_blk(dev, bi, block);

		max_copies = (whole_block) ? dev->param.chunks_per_block : 5;
		old_chunk = block * dev->param.chunks_per_block + dev->gc_chunk;

		for (  ;
		     ret_val == YAFFS_OK &&
		     dev->gc_chunk < dev->param.chunks_per_block &&
		     (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) &&
		     max_copies > 0; dev->gc_chunk++, old_chunk++) {
			if (yaffs_check_chunk_bit(dev, block, dev->gc_chunk)) {

				

				max_copies--;

				mark_flash = 1;

				yaffs_init_tags(&tags);

				yaffs_rd_chunk_tags_nand(dev, old_chunk,
							 buffer, &tags);

				object = yaffs_find_by_number(dev, tags.obj_id);

				yaffs_trace(YAFFS_TRACE_GC_DETAIL,
					"Collecting chunk in block %d, %d %d %d ",
					dev->gc_chunk, tags.obj_id,
					tags.chunk_id, tags.n_bytes);

				if (object && !yaffs_skip_verification(dev)) {
					if (tags.chunk_id == 0)
						matching_chunk =
						    object->hdr_chunk;
					else if (object->soft_del)
						matching_chunk = old_chunk;	
					else
						matching_chunk =
						    yaffs_find_chunk_in_file
						    (object, tags.chunk_id,
						     NULL);

					if (old_chunk != matching_chunk)
						yaffs_trace(YAFFS_TRACE_ERROR,
							"gc: page in gc mismatch: %d %d %d %d",
							old_chunk,
							matching_chunk,
							tags.obj_id,
						   	tags.chunk_id);

				}

				if (!object) {
					yaffs_trace(YAFFS_TRACE_ERROR,
						"page %d in gc has no object: %d %d %d ",
						old_chunk,
						tags.obj_id, tags.chunk_id,
						tags.n_bytes);
				}

				if (object &&
				    object->deleted &&
				    object->soft_del && tags.chunk_id != 0) {

					dev->n_free_chunks--;
					bi->soft_del_pages--;

					object->n_data_chunks--;

					if (object->n_data_chunks <= 0) {
						
						dev->gc_cleanup_list[dev->
								     n_clean_ups]
						    = tags.obj_id;
						dev->n_clean_ups++;
					}
					mark_flash = 0;
				} else if (0) {
					
					object->hdr_chunk = 0;
					yaffs_free_tnode(object->my_dev,
							 object->
							 variant.file_variant.
							 top);
					object->variant.file_variant.top = NULL;
					yaffs_generic_obj_del(object);

				} else if (object) {
					tags.serial_number++;

					dev->n_gc_copies++;

					if (tags.chunk_id == 0) {

						struct yaffs_obj_hdr *oh;
						oh = (struct yaffs_obj_hdr *)
						    buffer;

						oh->is_shrink = 0;
						tags.extra_is_shrink = 0;

						oh->shadows_obj = 0;
						oh->inband_shadowed_obj_id = 0;
						tags.extra_shadows = 0;

						
						if (object->variant_type ==
						    YAFFS_OBJECT_TYPE_FILE) {
							oh->file_size =
							    object->variant.
							    file_variant.
							    file_size;
							tags.extra_length =
							    oh->file_size;
						}

						yaffs_verify_oh(object, oh,
								&tags, 1);
						new_chunk =
						    yaffs_write_new_chunk(dev,
									  (u8 *)
					…