text: /*
   * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   *
   * Copyright (C) 2002-2011 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 "yaffs_yaffs1.h"
  #include "yportenv.h"
  #include "yaffs_trace.h"
  #include "yaffs_bitmap.h"
  #include "yaffs_getblockinfo.h"
  #include "yaffs_nand.h"
  #include "yaffs_attribs.h"
  
  int yaffs1_scan(struct yaffs_dev *dev)
  {
  	struct yaffs_ext_tags tags;
  	int blk;
  	int chunk;
  	int c;
  	int deleted;
  	enum yaffs_block_state state;
  	LIST_HEAD(hard_list);
  	struct yaffs_block_info *bi;
  	u32 seq_number;
  	struct yaffs_obj_hdr *oh;
  	struct yaffs_obj *in;
  	struct yaffs_obj *parent;
  	int alloc_failed = 0;
  	struct yaffs_shadow_fixer *shadow_fixers = NULL;
  	u8 *chunk_data;
  
  	yaffs_trace(YAFFS_TRACE_SCAN,
  		"yaffs1_scan starts  intstartblk %d intendblk %d...",
  		dev->internal_start_block, dev->internal_end_block);
  
  	chunk_data = yaffs_get_temp_buffer(dev);
  
  	dev->seq_number = YAFFS_LOWEST_SEQUENCE_NUMBER;
  
  	/* Scan all the blocks to determine their state */
  	bi = dev->block_info;
  	for (blk = dev->internal_start_block; blk <= dev->internal_end_block;
  	     blk++) {
  		yaffs_clear_chunk_bits(dev, blk);
  		bi->pages_in_use = 0;
  		bi->soft_del_pages = 0;
  
  		yaffs_query_init_block_state(dev, blk, &state, &seq_number);
  
  		bi->block_state = state;
  		bi->seq_number = seq_number;
  
  		if (bi->seq_number == YAFFS_SEQUENCE_BAD_BLOCK)
  			bi->block_state = state = YAFFS_BLOCK_STATE_DEAD;
  
  		yaffs_trace(YAFFS_TRACE_SCAN_DEBUG,
  			"Block scanning block %d state %d seq %d",
  			blk, state, seq_number);
  
  		if (state == YAFFS_BLOCK_STATE_DEAD) {
  			yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
  				"block %d is bad", blk);
  		} else if (state == YAFFS_BLOCK_STATE_EMPTY) {
  			yaffs_trace(YAFFS_TRACE_SCAN_DEBUG, "Block empty ");
  			dev->n_erased_blocks++;
  			dev->n_free_chunks += dev->param.chunks_per_block;
  		}
  		bi++;
  	}
  
  	/* For each block.... */
  	for (blk = dev->internal_start_block;
  	     !alloc_failed && blk <= dev->internal_end_block; blk++) {
  
  		cond_resched();
  
  		bi = yaffs_get_block_info(dev, blk);
  		state = bi->block_state;
  
  		deleted = 0;
  
  		/* For each chunk in each block that needs scanning.... */
  		for (c = 0;
  			!alloc_failed && c < dev->param.chunks_per_block &&
  			state == YAFFS_BLOCK_STATE_NEEDS_SCAN; c++) {
  			/* Read the tags and decide what to do */
  			chunk = blk * dev->param.chunks_per_block + c;
  
  			yaffs_rd_chunk_tags_nand(dev, chunk, NULL, &tags);
  
  			/* Let's have a good look at this chunk... */
  
  			if (tags.ecc_result == YAFFS_ECC_RESULT_UNFIXED ||
  			    tags.is_deleted) {
  				/* YAFFS1 only...
  				 * A deleted chunk
  				 */
  				deleted++;
  				dev->n_free_chunks++;
  			} else if (!tags.chunk_used) {
  				/* An unassigned chunk in the block
  				 * This means that either the block is empty or
  				 * this is the one being allocated from
  				 */
  
  				if (c == 0) {
  					/* We're looking at the first chunk in
  					 *the block so the block is unused */
  					state = YAFFS_BLOCK_STATE_EMPTY;
  					dev->n_erased_blocks++;
  				} else {
  					/* this is the block being allocated */
  					yaffs_trace(YAFFS_TRACE_SCAN,
  						" Allocating from %d %d",
  						blk, c);
  					state = YAFFS_BLOCK_STATE_ALLOCATING;
  					dev->alloc_block = blk;
  					dev->alloc_page = c;
  					dev->alloc_block_finder = blk;
  
  				}
  
  				dev->n_free_chunks +=
  				    (dev->param.chunks_per_block - c);
  			} else if (tags.chunk_id > 0) {
  				/* chunk_id > 0 so it is a data chunk... */
  				unsigned int endpos;
  
  				yaffs_set_chunk_bit(dev, blk, c);
  				bi->pages_in_use++;
  
  				in = yaffs_find_or_create_by_number(dev,
  							tags.obj_id,
  							YAFFS_OBJECT_TYPE_FILE);
  				/* PutChunkIntoFile checks for a clash
  				 * (two data chunks with the same chunk_id).
  				 */
  
  				if (!in)
  					alloc_failed = 1;
  
  				if (in) {
  					if (!yaffs_put_chunk_in_file
  					    (in, tags.chunk_id, chunk, 1))
  						alloc_failed = 1;
  				}
  
  				endpos =
  				    (tags.chunk_id - 1) *
  				    dev->data_bytes_per_chunk +
  				    tags.n_bytes;
  				if (in &&
  				    in->variant_type ==
  				     YAFFS_OBJECT_TYPE_FILE &&
  				    in->variant.file_variant.scanned_size <
  				      endpos) {
  					in->variant.file_variant.scanned_size =
  					    endpos;
  					if (!dev->param.use_header_file_size) {
  						in->variant.
  						    file_variant.file_size =
  						    in->variant.
  						    file_variant.scanned_size;
  					}
  
  				}
  			} else {
  				/* chunk_id == 0, so it is an ObjectHeader.
  				 * Make the object
  				 */
  				yaffs_set_chunk_bit(dev, blk, c);
  				bi->pages_in_use++;
  
  				yaffs_rd_chunk_tags_nand(dev, chunk,
  							 chunk_data, NULL);
  
  				oh = (struct yaffs_obj_hdr *)chunk_data;
  
  				in = yaffs_find_by_number(dev, tags.obj_id);
  				if (in && in->variant_type != oh->type) {
  					/* This should not happen, but somehow
  					 * Wev'e ended up with an obj_id that
  					 * has been reused but not yet deleted,
  					 * and worse still it has changed type.
  					 * Delete the old object.
  					 */
  
  					yaffs_del_obj(in);
  					in = NULL;
  				}
  
  				in = yaffs_find_or_create_by_number(dev,
  								tags.obj_id,
  								oh->type);
  
  				if (!in)
  					alloc_failed = 1;
  
  				if (in && oh->shadows_obj > 0) {
  
  					struct yaffs_shadow_fixer *fixer;
  					fixer =
  						kmalloc(sizeof
  						(struct yaffs_shadow_fixer),
  						GFP_NOFS);
  					if (fixer) {
  						fixer->next = shadow_fixers;
  						shadow_fixers = fixer;
  						fixer->obj_id = tags.obj_id;
  						fixer->shadowed_id =
  						    oh->shadows_obj;
  						yaffs_trace(YAFFS_TRACE_SCAN,
  							" Shadow fixer: %d shadows %d",
  							fixer->obj_id,
  							fixer->shadowed_id);
  
  					}
  
  				}
  
  				if (in && in->valid) {
  					/* We have already filled this one.
  					 * We have a duplicate and need to
  					 * resolve it. */
  
  					unsigned existing_serial = in->serial;
  					unsigned new_serial =
  					    tags.serial_number;
  
  					if (((existing_serial + 1) & 3) ==
  					    new_serial) {
  						/* Use new one - destroy the
  						 * exisiting one */
  						yaffs_chunk_del(dev,
  								in->hdr_chunk,
  								1, __LINE__);
  						in->valid = 0;
  					} else {
  						/* Use existing - destroy
  						 * this one. */
  						yaffs_chunk_del(dev, chunk, 1,
  								__LINE__);
  					}
  				}
  
  				if (in && !in->valid &&
  				    (tags.obj_id == YAFFS_OBJECTID_ROOT ||
  				     tags.obj_id ==
  				     YAFFS_OBJECTID_LOSTNFOUND)) {
  					/* We only load some info, don't fiddle
  					 * with directory structure */
  					in->valid = 1;
  					in->variant_type = oh->type;
  
  					in->yst_mode = oh->yst_mode;
  					yaffs_load_attribs(in, oh);
  					in->hdr_chunk = chunk;
  					in->serial = tags.serial_number;
  
  				} else if (in && !in->valid) {
  					/* we need to load this info */
  
  					in->valid = 1;
  					in->variant_type = oh->type;
  
  					in->yst_mode = oh->yst_mode;
  					yaffs_load_attribs(in, oh);
  					in->hdr_chunk = chunk;
  					in->serial = tags.serial_number;
  
  					yaffs_set_obj_name_from_oh(in, oh);
  					in->dirty = 0;
  
  					/* directory stuff...
  					 * hook up to parent
  					 */
  
  					parent =
  					    yaffs_find_or_create_by_number
  					    (dev, oh->parent_obj_id,
  					     YAFFS_OBJECT_TYPE_DIRECTORY);
  					if (!parent)
  						alloc_failed = 1;
  					if (parent && parent->variant_type ==
  					    YAFFS_OBJECT_TYPE_UNKNOWN) {
  						/* Set up as a directory */
  						parent->variant_type =
  						    YAFFS_OBJECT_TYPE_DIRECTORY;
  						INIT_LIST_HEAD(&parent->
  							variant.dir_variant.
  							children);
  					} else if (!parent ||
  						parent->variant_type !=
  						YAFFS_OBJECT_TYPE_DIRECTORY) {
  						/* Hoosterman, a problem....
  						 * We're trying to use a
  						 * non-directory as a directory
  						 */
  
  						yaffs_trace(YAFFS_TRACE_ERROR,
  							"yaffs tragedy: attempting to use non-directory as a directory in scan. Put in lost+found."
  							);
  						parent = dev->lost_n_found;
  					}
  
  					yaffs_add_obj_to_dir(parent, in);
  
  					switch (in->variant_type) {
  					case YAFFS_OBJECT_TYPE_UNKNOWN:
  						/* Todo got a problem */
  						break;
  					case YAFFS_OBJECT_TYPE_FILE:
  						if (dev->param.
  						    use_header_file_size)
  							in->variant.
  							file_variant.file_size
  							= yaffs_oh_to_size(oh);
  						break;
  					case YAFFS_OBJECT_TYPE_HARDLINK:
  						in->variant.
  						    hardlink_variant.equiv_id =
  						    oh->equiv_id;
  						list_add(&in->hard_links,
  								&hard_list);
  						break;
  					case YAFFS_OBJECT_TYPE_DIRECTORY:
  						/* Do nothing */
  						break;
  					case YAFFS_OBJECT_TYPE_SPECIAL:
  						/* Do nothing */
  						break;
  					case YAFFS_OBJECT_TYPE_SYMLINK:
  						in->variant.symlink_variant.
  						    alias =
  						    yaffs_clone_str(oh->alias);
  						if (!in->variant.
  						    symlink_variant.alias)
  							alloc_failed = 1;
  						break;
  					}
  				}
  			}
  		}
  
  		if (state == YAFFS_BLOCK_STATE_NEEDS_SCAN) {
  			/* If we got this far while scanning,
  			 * then the block is fully allocated. */
  			state = YAFFS_BLOCK_STATE_FULL;
  		}
  
  		if (state == YAFFS_BLOCK_STATE_ALLOCATING) {
  			/* If the block was partially allocated then
  			 * treat it as fully allocated. */
  			state = YAFFS_BLOCK_STATE_FULL;
  			dev->alloc_block = -1;
  		}
  
  		bi->block_state = state;
  
  		/* Now let's see if it was dirty */
  		if (bi->pages_in_use == 0 &&
  		    !bi->has_shrink_hdr &&
  		    bi->block_state == YAFFS_BLOCK_STATE_FULL)
  			yaffs_block_became_dirty(dev, blk);
  	}
  
  	/* Ok, we've done all the scanning.
  	 * Fix up the hard link chains.
  	 * We should now have scanned all the objects, now it's time to add
  	 * these hardlinks.
  	 */
  
  	yaffs_link_fixup(dev, &hard_list);
  
  	/*
  	 * Fix up any shadowed objects.
  	 * There should not be more than one of these.
  	 */
  	{
  		struct yaffs_shadow_fixer *fixer;
  		struct yaffs_obj *obj;
  
  		while (shadow_fixers) {
  			fixer = shadow_fixers;
  			shadow_fixers = fixer->next;
  			/* Complete the rename transaction by deleting the
  			 * shadowed object then setting the object header
  			 to unshadowed.
  			 */
  			obj = yaffs_find_by_number(dev, fixer->shadowed_id);
  			if (obj)
  				yaffs_del_obj(obj);
  
  			obj = yaffs_find_by_number(dev, fixer->obj_id);
  
  			if (obj)
  				yaffs_update_oh(obj, NULL, 1, 0, 0, NULL);
  
  			kfree(fixer);
  		}
  	}
  
  	yaffs_release_temp_buffer(dev, chunk_data);
  
  	if (alloc_failed)
  		return YAFFS_FAIL;
  
  	yaffs_trace(YAFFS_TRACE_SCAN, "yaffs1_scan ends");
  
  	return YAFFS_OK;
  }
  