generic: fold yaffs_git_2010_10_20 patch to generic/files
[15.05/openwrt.git] / target / linux / generic / files / fs / yaffs2 / yaffs_yaffs2.c
diff --git a/target/linux/generic/files/fs/yaffs2/yaffs_yaffs2.c b/target/linux/generic/files/fs/yaffs2/yaffs_yaffs2.c
new file mode 100644 (file)
index 0000000..58c3600
--- /dev/null
@@ -0,0 +1,1540 @@
+/*
+ * 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 "yaffs_guts.h"
+#include "yaffs_trace.h"
+#include "yaffs_yaffs2.h"
+#include "yaffs_checkptrw.h"
+#include "yaffs_bitmap.h"
+#include "yaffs_qsort.h"
+#include "yaffs_nand.h"
+#include "yaffs_getblockinfo.h"
+#include "yaffs_verify.h"
+
+/*
+ * Checkpoints are really no benefit on very small partitions.
+ *
+ * To save space on small partitions don't bother with checkpoints unless
+ * the partition is at least this big.
+ */
+#define YAFFS_CHECKPOINT_MIN_BLOCKS 60
+
+#define YAFFS_SMALL_HOLE_THRESHOLD 4
+
+
+/*
+ * Oldest Dirty Sequence Number handling.
+ */
+/* yaffs_calc_oldest_dirty_seq()
+ * yaffs2_find_oldest_dirty_seq()
+ * Calculate the oldest dirty sequence number if we don't know it.
+ */
+void yaffs_calc_oldest_dirty_seq(yaffs_dev_t *dev)
+{
+       int i;
+       unsigned seq;
+       unsigned block_no = 0;
+       yaffs_block_info_t *b;
+
+       if(!dev->param.is_yaffs2)
+               return;
+
+       /* Find the oldest dirty sequence number. */
+       seq = dev->seq_number + 1;
+       b = dev->block_info;
+       for (i = dev->internal_start_block; i <= dev->internal_end_block; i++) {
+               if (b->block_state == YAFFS_BLOCK_STATE_FULL &&
+                       (b->pages_in_use - b->soft_del_pages) < dev->param.chunks_per_block &&
+                       b->seq_number < seq) {
+                       seq = b->seq_number;
+                       block_no = i;
+               }
+               b++;
+       }
+
+       if(block_no){
+               dev->oldest_dirty_seq = seq;
+               dev->oldest_dirty_block = block_no;
+       }
+
+}
+
+
+void yaffs2_find_oldest_dirty_seq(yaffs_dev_t *dev)
+{
+       if(!dev->param.is_yaffs2)
+               return;
+
+       if(!dev->oldest_dirty_seq)
+               yaffs_calc_oldest_dirty_seq(dev);
+}
+
+/*
+ * yaffs_clear_oldest_dirty_seq()
+ * Called when a block is erased or marked bad. (ie. when its seq_number
+ * becomes invalid). If the value matches the oldest then we clear 
+ * dev->oldest_dirty_seq to force its recomputation.
+ */
+void yaffs2_clear_oldest_dirty_seq(yaffs_dev_t *dev, yaffs_block_info_t *bi)
+{
+
+       if(!dev->param.is_yaffs2)
+               return;
+
+       if(!bi || bi->seq_number == dev->oldest_dirty_seq){
+               dev->oldest_dirty_seq = 0;
+               dev->oldest_dirty_block = 0;
+       }
+}
+
+/*
+ * yaffs2_update_oldest_dirty_seq()
+ * Update the oldest dirty sequence number whenever we dirty a block.
+ * Only do this if the oldest_dirty_seq is actually being tracked.
+ */
+void yaffs2_update_oldest_dirty_seq(yaffs_dev_t *dev, unsigned block_no, yaffs_block_info_t *bi)
+{
+       if(!dev->param.is_yaffs2)
+               return;
+
+       if(dev->oldest_dirty_seq){
+               if(dev->oldest_dirty_seq > bi->seq_number){
+                       dev->oldest_dirty_seq = bi->seq_number;
+                       dev->oldest_dirty_block = block_no;
+               }
+       }
+}
+
+int yaffs_block_ok_for_gc(yaffs_dev_t *dev,
+                                       yaffs_block_info_t *bi)
+{
+
+       if (!dev->param.is_yaffs2)
+               return 1;       /* disqualification only applies to yaffs2. */
+
+       if (!bi->has_shrink_hdr)
+               return 1;       /* can gc */
+
+       yaffs2_find_oldest_dirty_seq(dev);
+
+       /* Can't do gc of this block if there are any blocks older than this one that have
+        * discarded pages.
+        */
+       return (bi->seq_number <= dev->oldest_dirty_seq);
+}
+
+/*
+ * yaffs2_find_refresh_block()
+ * periodically finds the oldest full block by sequence number for refreshing.
+ * Only for yaffs2.
+ */
+__u32 yaffs2_find_refresh_block(yaffs_dev_t *dev)
+{
+       __u32 b ;
+
+       __u32 oldest = 0;
+       __u32 oldestSequence = 0;
+
+       yaffs_block_info_t *bi;
+
+       if(!dev->param.is_yaffs2)
+               return oldest;
+
+       /*
+        * If refresh period < 10 then refreshing is disabled.
+        */
+       if(dev->param.refresh_period < 10)
+               return oldest;
+
+        /*
+         * Fix broken values.
+         */
+        if(dev->refresh_skip > dev->param.refresh_period)
+                dev->refresh_skip = dev->param.refresh_period;
+
+       if(dev->refresh_skip > 0)
+               return oldest;
+
+       /*
+        * Refresh skip is now zero.
+        * We'll do a refresh this time around....
+        * Update the refresh skip and find the oldest block.
+        */
+       dev->refresh_skip = dev->param.refresh_period;
+       dev->refresh_count++;
+       bi = dev->block_info;
+       for (b = dev->internal_start_block; b <=dev->internal_end_block; b++){
+
+               if (bi->block_state == YAFFS_BLOCK_STATE_FULL){
+
+                       if(oldest < 1 ||
+                                bi->seq_number < oldestSequence){
+                                oldest = b;
+                                oldestSequence = bi->seq_number;
+                        }
+               }
+               bi++;
+       }
+
+       if (oldest > 0) {
+               T(YAFFS_TRACE_GC,
+                 (TSTR("GC refresh count %d selected block %d with seq_number %d" TENDSTR),
+                  dev->refresh_count, oldest, oldestSequence));
+       }
+
+       return oldest;
+}
+
+int yaffs2_checkpt_required(yaffs_dev_t *dev)
+{
+       int nblocks;
+       
+       if(!dev->param.is_yaffs2)
+               return 0;
+       
+       nblocks = dev->internal_end_block - dev->internal_start_block + 1 ;
+
+       return  !dev->param.skip_checkpt_wr &&
+               !dev->read_only &&
+               (nblocks >= YAFFS_CHECKPOINT_MIN_BLOCKS);
+}
+
+int yaffs_calc_checkpt_blocks_required(yaffs_dev_t *dev)
+{
+       int retval;
+
+       if(!dev->param.is_yaffs2)
+               return 0;
+
+       if (!dev->checkpoint_blocks_required &&
+               yaffs2_checkpt_required(dev)){
+               /* Not a valid value so recalculate */
+               int n_bytes = 0;
+               int nBlocks;
+               int devBlocks = (dev->param.end_block - dev->param.start_block + 1);
+
+               n_bytes += sizeof(yaffs_checkpt_validty_t);
+               n_bytes += sizeof(yaffs_checkpt_dev_t);
+               n_bytes += devBlocks * sizeof(yaffs_block_info_t);
+               n_bytes += devBlocks * dev->chunk_bit_stride;
+               n_bytes += (sizeof(yaffs_checkpt_obj_t) + sizeof(__u32)) * (dev->n_obj);
+               n_bytes += (dev->tnode_size + sizeof(__u32)) * (dev->n_tnodes);
+               n_bytes += sizeof(yaffs_checkpt_validty_t);
+               n_bytes += sizeof(__u32); /* checksum*/
+
+               /* Round up and add 2 blocks to allow for some bad blocks, so add 3 */
+
+               nBlocks = (n_bytes/(dev->data_bytes_per_chunk * dev->param.chunks_per_block)) + 3;
+
+               dev->checkpoint_blocks_required = nBlocks;
+       }
+
+       retval = dev->checkpoint_blocks_required - dev->blocks_in_checkpt;
+       if(retval < 0)
+               retval = 0;
+       return retval;
+}
+
+/*--------------------- Checkpointing --------------------*/
+
+
+static int yaffs2_wr_checkpt_validity_marker(yaffs_dev_t *dev, int head)
+{
+       yaffs_checkpt_validty_t cp;
+
+       memset(&cp, 0, sizeof(cp));
+
+       cp.struct_type = sizeof(cp);
+       cp.magic = YAFFS_MAGIC;
+       cp.version = YAFFS_CHECKPOINT_VERSION;
+       cp.head = (head) ? 1 : 0;
+
+       return (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp)) ?
+               1 : 0;
+}
+
+static int yaffs2_rd_checkpt_validty_marker(yaffs_dev_t *dev, int head)
+{
+       yaffs_checkpt_validty_t cp;
+       int ok;
+
+       ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
+
+       if (ok)
+               ok = (cp.struct_type == sizeof(cp)) &&
+                    (cp.magic == YAFFS_MAGIC) &&
+                    (cp.version == YAFFS_CHECKPOINT_VERSION) &&
+                    (cp.head == ((head) ? 1 : 0));
+       return ok ? 1 : 0;
+}
+
+static void yaffs2_dev_to_checkpt_dev(yaffs_checkpt_dev_t *cp,
+                                          yaffs_dev_t *dev)
+{
+       cp->n_erased_blocks = dev->n_erased_blocks;
+       cp->alloc_block = dev->alloc_block;
+       cp->alloc_page = dev->alloc_page;
+       cp->n_free_chunks = dev->n_free_chunks;
+
+       cp->n_deleted_files = dev->n_deleted_files;
+       cp->n_unlinked_files = dev->n_unlinked_files;
+       cp->n_bg_deletions = dev->n_bg_deletions;
+       cp->seq_number = dev->seq_number;
+
+}
+
+static void yaffs_checkpt_dev_to_dev(yaffs_dev_t *dev,
+                                          yaffs_checkpt_dev_t *cp)
+{
+       dev->n_erased_blocks = cp->n_erased_blocks;
+       dev->alloc_block = cp->alloc_block;
+       dev->alloc_page = cp->alloc_page;
+       dev->n_free_chunks = cp->n_free_chunks;
+
+       dev->n_deleted_files = cp->n_deleted_files;
+       dev->n_unlinked_files = cp->n_unlinked_files;
+       dev->n_bg_deletions = cp->n_bg_deletions;
+       dev->seq_number = cp->seq_number;
+}
+
+
+static int yaffs2_wr_checkpt_dev(yaffs_dev_t *dev)
+{
+       yaffs_checkpt_dev_t cp;
+       __u32 n_bytes;
+       __u32 nBlocks = (dev->internal_end_block - dev->internal_start_block + 1);
+
+       int ok;
+
+       /* Write device runtime values*/
+       yaffs2_dev_to_checkpt_dev(&cp, dev);
+       cp.struct_type = sizeof(cp);
+
+       ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
+
+       /* Write block info */
+       if (ok) {
+               n_bytes = nBlocks * sizeof(yaffs_block_info_t);
+               ok = (yaffs2_checkpt_wr(dev, dev->block_info, n_bytes) == n_bytes);
+       }
+
+       /* Write chunk bits */
+       if (ok) {
+               n_bytes = nBlocks * dev->chunk_bit_stride;
+               ok = (yaffs2_checkpt_wr(dev, dev->chunk_bits, n_bytes) == n_bytes);
+       }
+       return   ok ? 1 : 0;
+
+}
+
+static int yaffs2_rd_checkpt_dev(yaffs_dev_t *dev)
+{
+       yaffs_checkpt_dev_t cp;
+       __u32 n_bytes;
+       __u32 nBlocks = (dev->internal_end_block - dev->internal_start_block + 1);
+
+       int ok;
+
+       ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
+       if (!ok)
+               return 0;
+
+       if (cp.struct_type != sizeof(cp))
+               return 0;
+
+
+       yaffs_checkpt_dev_to_dev(dev, &cp);
+
+       n_bytes = nBlocks * sizeof(yaffs_block_info_t);
+
+       ok = (yaffs2_checkpt_rd(dev, dev->block_info, n_bytes) == n_bytes);
+
+       if (!ok)
+               return 0;
+       n_bytes = nBlocks * dev->chunk_bit_stride;
+
+       ok = (yaffs2_checkpt_rd(dev, dev->chunk_bits, n_bytes) == n_bytes);
+
+       return ok ? 1 : 0;
+}
+
+static void yaffs2_obj_checkpt_obj(yaffs_checkpt_obj_t *cp,
+                                          yaffs_obj_t *obj)
+{
+
+       cp->obj_id = obj->obj_id;
+       cp->parent_id = (obj->parent) ? obj->parent->obj_id : 0;
+       cp->hdr_chunk = obj->hdr_chunk;
+       cp->variant_type = obj->variant_type;
+       cp->deleted = obj->deleted;
+       cp->soft_del = obj->soft_del;
+       cp->unlinked = obj->unlinked;
+       cp->fake = obj->fake;
+       cp->rename_allowed = obj->rename_allowed;
+       cp->unlink_allowed = obj->unlink_allowed;
+       cp->serial = obj->serial;
+       cp->n_data_chunks = obj->n_data_chunks;
+
+       if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
+               cp->size_or_equiv_obj = obj->variant.file_variant.file_size;
+       else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
+               cp->size_or_equiv_obj = obj->variant.hardlink_variant.equiv_id;
+}
+
+static int taffs2_checkpt_obj_to_obj(yaffs_obj_t *obj, yaffs_checkpt_obj_t *cp)
+{
+
+       yaffs_obj_t *parent;
+
+       if (obj->variant_type != cp->variant_type) {
+               T(YAFFS_TRACE_ERROR, (TSTR("Checkpoint read object %d type %d "
+                       TCONT("chunk %d does not match existing object type %d")
+                       TENDSTR), cp->obj_id, cp->variant_type, cp->hdr_chunk,
+                       obj->variant_type));
+               return 0;
+       }
+
+       obj->obj_id = cp->obj_id;
+
+       if (cp->parent_id)
+               parent = yaffs_find_or_create_by_number(
+                                       obj->my_dev,
+                                       cp->parent_id,
+                                       YAFFS_OBJECT_TYPE_DIRECTORY);
+       else
+               parent = NULL;
+
+       if (parent) {
+               if (parent->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
+                       T(YAFFS_TRACE_ALWAYS, (TSTR("Checkpoint read object %d parent %d type %d"
+                               TCONT(" chunk %d Parent type, %d, not directory")
+                               TENDSTR),
+                               cp->obj_id, cp->parent_id, cp->variant_type,
+                               cp->hdr_chunk, parent->variant_type));
+                       return 0;
+               }
+               yaffs_add_obj_to_dir(parent, obj);
+       }
+
+       obj->hdr_chunk = cp->hdr_chunk;
+       obj->variant_type = cp->variant_type;
+       obj->deleted = cp->deleted;
+       obj->soft_del = cp->soft_del;
+       obj->unlinked = cp->unlinked;
+       obj->fake = cp->fake;
+       obj->rename_allowed = cp->rename_allowed;
+       obj->unlink_allowed = cp->unlink_allowed;
+       obj->serial = cp->serial;
+       obj->n_data_chunks = cp->n_data_chunks;
+
+       if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
+               obj->variant.file_variant.file_size = cp->size_or_equiv_obj;
+       else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK)
+               obj->variant.hardlink_variant.equiv_id = cp->size_or_equiv_obj;
+
+       if (obj->hdr_chunk > 0)
+               obj->lazy_loaded = 1;
+       return 1;
+}
+
+
+
+static int yaffs2_checkpt_tnode_worker(yaffs_obj_t *in, yaffs_tnode_t *tn,
+                                       __u32 level, int chunk_offset)
+{
+       int i;
+       yaffs_dev_t *dev = in->my_dev;
+       int ok = 1;
+
+       if (tn) {
+               if (level > 0) {
+
+                       for (i = 0; i < YAFFS_NTNODES_INTERNAL && ok; i++) {
+                               if (tn->internal[i]) {
+                                       ok = yaffs2_checkpt_tnode_worker(in,
+                                                       tn->internal[i],
+                                                       level - 1,
+                                                       (chunk_offset<<YAFFS_TNODES_INTERNAL_BITS) + i);
+                               }
+                       }
+               } else if (level == 0) {
+                       __u32 baseOffset = chunk_offset <<  YAFFS_TNODES_LEVEL0_BITS;
+                       ok = (yaffs2_checkpt_wr(dev, &baseOffset, sizeof(baseOffset)) == sizeof(baseOffset));
+                       if (ok)
+                               ok = (yaffs2_checkpt_wr(dev, tn, dev->tnode_size) == dev->tnode_size);
+               }
+       }
+
+       return ok;
+
+}
+
+static int yaffs2_wr_checkpt_tnodes(yaffs_obj_t *obj)
+{
+       __u32 endMarker = ~0;
+       int ok = 1;
+
+       if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE) {
+               ok = yaffs2_checkpt_tnode_worker(obj,
+                                           obj->variant.file_variant.top,
+                                           obj->variant.file_variant.top_level,
+                                           0);
+               if (ok)
+                       ok = (yaffs2_checkpt_wr(obj->my_dev, &endMarker, sizeof(endMarker)) ==
+                               sizeof(endMarker));
+       }
+
+       return ok ? 1 : 0;
+}
+
+static int yaffs2_rd_checkpt_tnodes(yaffs_obj_t *obj)
+{
+       __u32 baseChunk;
+       int ok = 1;
+       yaffs_dev_t *dev = obj->my_dev;
+       yaffs_file_s *fileStructPtr = &obj->variant.file_variant;
+       yaffs_tnode_t *tn;
+       int nread = 0;
+
+       ok = (yaffs2_checkpt_rd(dev, &baseChunk, sizeof(baseChunk)) == sizeof(baseChunk));
+
+       while (ok && (~baseChunk)) {
+               nread++;
+               /* Read level 0 tnode */
+
+
+               tn = yaffs_get_tnode(dev);
+               if (tn){
+                       ok = (yaffs2_checkpt_rd(dev, tn, dev->tnode_size) == dev->tnode_size);
+               } else
+                       ok = 0;
+
+               if (tn && ok)
+                       ok = yaffs_add_find_tnode_0(dev,
+                                                       fileStructPtr,
+                                                       baseChunk,
+                                                       tn) ? 1 : 0;
+
+               if (ok)
+                       ok = (yaffs2_checkpt_rd(dev, &baseChunk, sizeof(baseChunk)) == sizeof(baseChunk));
+
+       }
+
+       T(YAFFS_TRACE_CHECKPOINT, (
+               TSTR("Checkpoint read tnodes %d records, last %d. ok %d" TENDSTR),
+               nread, baseChunk, ok));
+
+       return ok ? 1 : 0;
+}
+
+
+static int yaffs2_wr_checkpt_objs(yaffs_dev_t *dev)
+{
+       yaffs_obj_t *obj;
+       yaffs_checkpt_obj_t cp;
+       int i;
+       int ok = 1;
+       struct ylist_head *lh;
+
+
+       /* Iterate through the objects in each hash entry,
+        * dumping them to the checkpointing stream.
+        */
+
+       for (i = 0; ok &&  i <  YAFFS_NOBJECT_BUCKETS; i++) {
+               ylist_for_each(lh, &dev->obj_bucket[i].list) {
+                       if (lh) {
+                               obj = ylist_entry(lh, yaffs_obj_t, hash_link);
+                               if (!obj->defered_free) {
+                                       yaffs2_obj_checkpt_obj(&cp, obj);
+                                       cp.struct_type = sizeof(cp);
+
+                                       T(YAFFS_TRACE_CHECKPOINT, (
+                                               TSTR("Checkpoint write object %d parent %d type %d chunk %d obj addr %p" TENDSTR),
+                                               cp.obj_id, cp.parent_id, cp.variant_type, cp.hdr_chunk, obj));
+
+                                       ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
+
+                                       if (ok && obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
+                                               ok = yaffs2_wr_checkpt_tnodes(obj);
+                               }
+                       }
+               }
+       }
+
+       /* Dump end of list */
+       memset(&cp, 0xFF, sizeof(yaffs_checkpt_obj_t));
+       cp.struct_type = sizeof(cp);
+
+       if (ok)
+               ok = (yaffs2_checkpt_wr(dev, &cp, sizeof(cp)) == sizeof(cp));
+
+       return ok ? 1 : 0;
+}
+
+static int yaffs2_rd_checkpt_objs(yaffs_dev_t *dev)
+{
+       yaffs_obj_t *obj;
+       yaffs_checkpt_obj_t cp;
+       int ok = 1;
+       int done = 0;
+       yaffs_obj_t *hard_list = NULL;
+
+       while (ok && !done) {
+               ok = (yaffs2_checkpt_rd(dev, &cp, sizeof(cp)) == sizeof(cp));
+               if (cp.struct_type != sizeof(cp)) {
+                       T(YAFFS_TRACE_CHECKPOINT, (TSTR("struct size %d instead of %d ok %d"TENDSTR),
+                               cp.struct_type, (int)sizeof(cp), ok));
+                       ok = 0;
+               }
+
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("Checkpoint read object %d parent %d type %d chunk %d " TENDSTR),
+                       cp.obj_id, cp.parent_id, cp.variant_type, cp.hdr_chunk));
+
+               if (ok && cp.obj_id == ~0)
+                       done = 1;
+               else if (ok) {
+                       obj = yaffs_find_or_create_by_number(dev, cp.obj_id, cp.variant_type);
+                       if (obj) {
+                               ok = taffs2_checkpt_obj_to_obj(obj, &cp);
+                               if (!ok)
+                                       break;
+                               if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE) {
+                                       ok = yaffs2_rd_checkpt_tnodes(obj);
+                               } else if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK) {
+                                       obj->hard_links.next =
+                                               (struct ylist_head *) hard_list;
+                                       hard_list = obj;
+                               }
+                       } else
+                               ok = 0;
+               }
+       }
+
+       if (ok)
+               yaffs_link_fixup(dev, hard_list);
+
+       return ok ? 1 : 0;
+}
+
+static int yaffs2_wr_checkpt_sum(yaffs_dev_t *dev)
+{
+       __u32 checkpt_sum;
+       int ok;
+
+       yaffs2_get_checkpt_sum(dev, &checkpt_sum);
+
+       ok = (yaffs2_checkpt_wr(dev, &checkpt_sum, sizeof(checkpt_sum)) == sizeof(checkpt_sum));
+
+       if (!ok)
+               return 0;
+
+       return 1;
+}
+
+static int yaffs2_rd_checkpt_sum(yaffs_dev_t *dev)
+{
+       __u32 checkpt_sum0;
+       __u32 checkpt_sum1;
+       int ok;
+
+       yaffs2_get_checkpt_sum(dev, &checkpt_sum0);
+
+       ok = (yaffs2_checkpt_rd(dev, &checkpt_sum1, sizeof(checkpt_sum1)) == sizeof(checkpt_sum1));
+
+       if (!ok)
+               return 0;
+
+       if (checkpt_sum0 != checkpt_sum1)
+               return 0;
+
+       return 1;
+}
+
+
+static int yaffs2_wr_checkpt_data(yaffs_dev_t *dev)
+{
+       int ok = 1;
+
+       if (!yaffs2_checkpt_required(dev)) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("skipping checkpoint write" TENDSTR)));
+               ok = 0;
+       }
+
+       if (ok)
+               ok = yaffs2_checkpt_open(dev, 1);
+
+       if (ok) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("write checkpoint validity" TENDSTR)));
+               ok = yaffs2_wr_checkpt_validity_marker(dev, 1);
+       }
+       if (ok) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("write checkpoint device" TENDSTR)));
+               ok = yaffs2_wr_checkpt_dev(dev);
+       }
+       if (ok) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("write checkpoint objects" TENDSTR)));
+               ok = yaffs2_wr_checkpt_objs(dev);
+       }
+       if (ok) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("write checkpoint validity" TENDSTR)));
+               ok = yaffs2_wr_checkpt_validity_marker(dev, 0);
+       }
+
+       if (ok)
+               ok = yaffs2_wr_checkpt_sum(dev);
+
+       if (!yaffs_checkpt_close(dev))
+               ok = 0;
+
+       if (ok)
+               dev->is_checkpointed = 1;
+       else
+               dev->is_checkpointed = 0;
+
+       return dev->is_checkpointed;
+}
+
+static int yaffs2_rd_checkpt_data(yaffs_dev_t *dev)
+{
+       int ok = 1;
+       
+       if(!dev->param.is_yaffs2)
+               ok = 0;
+
+       if (ok && dev->param.skip_checkpt_rd) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("skipping checkpoint read" TENDSTR)));
+               ok = 0;
+       }
+
+       if (ok)
+               ok = yaffs2_checkpt_open(dev, 0); /* open for read */
+
+       if (ok) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("read checkpoint validity" TENDSTR)));
+               ok = yaffs2_rd_checkpt_validty_marker(dev, 1);
+       }
+       if (ok) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("read checkpoint device" TENDSTR)));
+               ok = yaffs2_rd_checkpt_dev(dev);
+       }
+       if (ok) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("read checkpoint objects" TENDSTR)));
+               ok = yaffs2_rd_checkpt_objs(dev);
+       }
+       if (ok) {
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("read checkpoint validity" TENDSTR)));
+               ok = yaffs2_rd_checkpt_validty_marker(dev, 0);
+       }
+
+       if (ok) {
+               ok = yaffs2_rd_checkpt_sum(dev);
+               T(YAFFS_TRACE_CHECKPOINT, (TSTR("read checkpoint checksum %d" TENDSTR), ok));
+       }
+
+       if (!yaffs_checkpt_close(dev))
+               ok = 0;
+
+       if (ok)
+               dev->is_checkpointed = 1;
+       else
+               dev->is_checkpointed = 0;
+
+       return ok ? 1 : 0;
+
+}
+
+void yaffs2_checkpt_invalidate(yaffs_dev_t *dev)
+{
+       if (dev->is_checkpointed ||
+                       dev->blocks_in_checkpt > 0) {
+               dev->is_checkpointed = 0;
+               yaffs2_checkpt_invalidate_stream(dev);
+       }
+       if (dev->param.sb_dirty_fn)
+               dev->param.sb_dirty_fn(dev);
+}
+
+
+int yaffs_checkpoint_save(yaffs_dev_t *dev)
+{
+
+       T(YAFFS_TRACE_CHECKPOINT, (TSTR("save entry: is_checkpointed %d"TENDSTR), dev->is_checkpointed));
+
+       yaffs_verify_objects(dev);
+       yaffs_verify_blocks(dev);
+       yaffs_verify_free_chunks(dev);
+
+       if (!dev->is_checkpointed) {
+               yaffs2_checkpt_invalidate(dev);
+               yaffs2_wr_checkpt_data(dev);
+       }
+
+       T(YAFFS_TRACE_ALWAYS, (TSTR("save exit: is_checkpointed %d"TENDSTR), dev->is_checkpointed));
+
+       return dev->is_checkpointed;
+}
+
+int yaffs2_checkpt_restore(yaffs_dev_t *dev)
+{
+       int retval;
+       T(YAFFS_TRACE_CHECKPOINT, (TSTR("restore entry: is_checkpointed %d"TENDSTR), dev->is_checkpointed));
+
+       retval = yaffs2_rd_checkpt_data(dev);
+
+       if (dev->is_checkpointed) {
+               yaffs_verify_objects(dev);
+               yaffs_verify_blocks(dev);
+               yaffs_verify_free_chunks(dev);
+       }
+
+       T(YAFFS_TRACE_CHECKPOINT, (TSTR("restore exit: is_checkpointed %d"TENDSTR), dev->is_checkpointed));
+
+       return retval;
+}
+
+int yaffs2_handle_hole(yaffs_obj_t *obj, loff_t new_size)
+{
+       /* if newsSize > oldFileSize.
+        * We're going to be writing a hole.
+        * If the hole is small then write zeros otherwise write a start of hole marker.
+        */
+               
+
+       loff_t oldFileSize;
+       int increase;
+       int smallHole   ;
+       int result = YAFFS_OK;
+       yaffs_dev_t *dev = NULL;
+
+       __u8 *localBuffer = NULL;
+       
+       int smallIncreaseOk = 0;
+       
+       if(!obj)
+               return YAFFS_FAIL;
+
+       if(obj->variant_type != YAFFS_OBJECT_TYPE_FILE)
+               return YAFFS_FAIL;
+       
+       dev = obj->my_dev;
+       
+       /* Bail out if not yaffs2 mode */
+       if(!dev->param.is_yaffs2)
+               return YAFFS_OK;
+
+       oldFileSize = obj->variant.file_variant.file_size;
+
+       if (new_size <= oldFileSize)
+               return YAFFS_OK;
+
+       increase = new_size - oldFileSize;
+
+       if(increase < YAFFS_SMALL_HOLE_THRESHOLD * dev->data_bytes_per_chunk &&
+               yaffs_check_alloc_available(dev, YAFFS_SMALL_HOLE_THRESHOLD + 1))
+               smallHole = 1;
+       else
+               smallHole = 0;
+
+       if(smallHole)
+               localBuffer= yaffs_get_temp_buffer(dev, __LINE__);
+       
+       if(localBuffer){
+               /* fill hole with zero bytes */
+               int pos = oldFileSize;
+               int thisWrite;
+               int written;
+               memset(localBuffer,0,dev->data_bytes_per_chunk);
+               smallIncreaseOk = 1;
+
+               while(increase > 0 && smallIncreaseOk){
+                       thisWrite = increase;
+                       if(thisWrite > dev->data_bytes_per_chunk)
+                               thisWrite = dev->data_bytes_per_chunk;
+                       written = yaffs_do_file_wr(obj,localBuffer,pos,thisWrite,0);
+                       if(written == thisWrite){
+                               pos += thisWrite;
+                               increase -= thisWrite;
+                       } else
+                               smallIncreaseOk = 0;
+               }
+
+               yaffs_release_temp_buffer(dev,localBuffer,__LINE__);
+
+               /* If we were out of space then reverse any chunks we've added */               
+               if(!smallIncreaseOk)
+                       yaffs_resize_file_down(obj, oldFileSize);
+       }
+       
+       if (!smallIncreaseOk &&
+               obj->parent &&
+               obj->parent->obj_id != YAFFS_OBJECTID_UNLINKED &&
+               obj->parent->obj_id != YAFFS_OBJECTID_DELETED){
+               /* Write a hole start header with the old file size */
+               yaffs_update_oh(obj, NULL, 0, 1, 0, NULL);
+       }
+
+       return result;
+
+}
+
+
+typedef struct {
+       int seq;
+       int block;
+} yaffs_BlockIndex;
+
+
+static int yaffs2_ybicmp(const void *a, const void *b)
+{
+       register int aseq = ((yaffs_BlockIndex *)a)->seq;
+       register int bseq = ((yaffs_BlockIndex *)b)->seq;
+       register int ablock = ((yaffs_BlockIndex *)a)->block;
+       register int bblock = ((yaffs_BlockIndex *)b)->block;
+       if (aseq == bseq)
+               return ablock - bblock;
+       else
+               return aseq - bseq;
+}
+
+int yaffs2_scan_backwards(yaffs_dev_t *dev)
+{
+       yaffs_ext_tags tags;
+       int blk;
+       int blockIterator;
+       int startIterator;
+       int endIterator;
+       int nBlocksToScan = 0;
+
+       int chunk;
+       int result;
+       int c;
+       int deleted;
+       yaffs_block_state_t state;
+       yaffs_obj_t *hard_list = NULL;
+       yaffs_block_info_t *bi;
+       __u32 seq_number;
+       yaffs_obj_header *oh;
+       yaffs_obj_t *in;
+       yaffs_obj_t *parent;
+       int nBlocks = dev->internal_end_block - dev->internal_start_block + 1;
+       int itsUnlinked;
+       __u8 *chunkData;
+
+       int file_size;
+       int is_shrink;
+       int foundChunksInBlock;
+       int equiv_id;
+       int alloc_failed = 0;
+
+
+       yaffs_BlockIndex *blockIndex = NULL;
+       int altBlockIndex = 0;
+
+       T(YAFFS_TRACE_SCAN,
+         (TSTR
+          ("yaffs2_scan_backwards starts  intstartblk %d intendblk %d..."
+           TENDSTR), dev->internal_start_block, dev->internal_end_block));
+
+
+       dev->seq_number = YAFFS_LOWEST_SEQUENCE_NUMBER;
+
+       blockIndex = YMALLOC(nBlocks * sizeof(yaffs_BlockIndex));
+
+       if (!blockIndex) {
+               blockIndex = YMALLOC_ALT(nBlocks * sizeof(yaffs_BlockIndex));
+               altBlockIndex = 1;
+       }
+
+       if (!blockIndex) {
+               T(YAFFS_TRACE_SCAN,
+                 (TSTR("yaffs2_scan_backwards() could not allocate block index!" TENDSTR)));
+               return YAFFS_FAIL;
+       }
+
+       dev->blocks_in_checkpt = 0;
+
+       chunkData = yaffs_get_temp_buffer(dev, __LINE__);
+
+       /* 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_CHECKPOINT_DATA)
+                       bi->block_state = state = YAFFS_BLOCK_STATE_CHECKPOINT;
+               if (bi->seq_number == YAFFS_SEQUENCE_BAD_BLOCK)
+                       bi->block_state = state = YAFFS_BLOCK_STATE_DEAD;
+
+               T(YAFFS_TRACE_SCAN_DEBUG,
+                 (TSTR("Block scanning block %d state %d seq %d" TENDSTR), blk,
+                  state, seq_number));
+
+
+               if (state == YAFFS_BLOCK_STATE_CHECKPOINT) {
+                       dev->blocks_in_checkpt++;
+
+               } else if (state == YAFFS_BLOCK_STATE_DEAD) {
+                       T(YAFFS_TRACE_BAD_BLOCKS,
+                         (TSTR("block %d is bad" TENDSTR), blk));
+               } else if (state == YAFFS_BLOCK_STATE_EMPTY) {
+                       T(YAFFS_TRACE_SCAN_DEBUG,
+                         (TSTR("Block empty " TENDSTR)));
+                       dev->n_erased_blocks++;
+                       dev->n_free_chunks += dev->param.chunks_per_block;
+               } else if (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
+
+                       /* Determine the highest sequence number */
+                       if (seq_number >= YAFFS_LOWEST_SEQUENCE_NUMBER &&
+                           seq_number < YAFFS_HIGHEST_SEQUENCE_NUMBER) {
+
+                               blockIndex[nBlocksToScan].seq = seq_number;
+                               blockIndex[nBlocksToScan].block = blk;
+
+                               nBlocksToScan++;
+
+                               if (seq_number >= dev->seq_number)
+                                       dev->seq_number = seq_number;
+                       } else {
+                               /* TODO: Nasty sequence number! */
+                               T(YAFFS_TRACE_SCAN,
+                                 (TSTR
+                                  ("Block scanning block %d has bad sequence number %d"
+                                   TENDSTR), blk, seq_number));
+
+                       }
+               }
+               bi++;
+       }
+
+       T(YAFFS_TRACE_SCAN,
+       (TSTR("%d blocks to be sorted..." TENDSTR), nBlocksToScan));
+
+
+
+       YYIELD();
+
+       /* Sort the blocks by sequence number*/
+       yaffs_qsort(blockIndex, nBlocksToScan, sizeof(yaffs_BlockIndex), yaffs2_ybicmp);
+
+       YYIELD();
+
+       T(YAFFS_TRACE_SCAN, (TSTR("...done" TENDSTR)));
+
+       /* Now scan the blocks looking at the data. */
+       startIterator = 0;
+       endIterator = nBlocksToScan - 1;
+       T(YAFFS_TRACE_SCAN_DEBUG,
+         (TSTR("%d blocks to be scanned" TENDSTR), nBlocksToScan));
+
+       /* For each block.... backwards */
+       for (blockIterator = endIterator; !alloc_failed && blockIterator >= startIterator;
+                       blockIterator--) {
+               /* Cooperative multitasking! This loop can run for so
+                  long that watchdog timers expire. */
+               YYIELD();
+
+               /* get the block to scan in the correct order */
+               blk = blockIndex[blockIterator].block;
+
+               bi = yaffs_get_block_info(dev, blk);
+
+
+               state = bi->block_state;
+
+               deleted = 0;
+
+               /* For each chunk in each block that needs scanning.... */
+               foundChunksInBlock = 0;
+               for (c = dev->param.chunks_per_block - 1;
+                    !alloc_failed && c >= 0 &&
+                    (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING ||
+                     state == YAFFS_BLOCK_STATE_ALLOCATING); c--) {
+                       /* Scan backwards...
+                        * Read the tags and decide what to do
+                        */
+
+                       chunk = blk * dev->param.chunks_per_block + c;
+
+                       result = yaffs_rd_chunk_tags_nand(dev, chunk, NULL,
+                                                       &tags);
+
+                       /* Let's have a good look at this chunk... */
+
+                       if (!tags.chunk_used) {
+                               /* An unassigned chunk in the block.
+                                * If there are used chunks after this one, then
+                                * it is a chunk that was skipped due to failing the erased
+                                * check. Just skip it so that it can be deleted.
+                                * But, more typically, We get here when this is an unallocated
+                                * chunk and his means that either the block is empty or
+                                * this is the one being allocated from
+                                */
+
+                               if (foundChunksInBlock) {
+                                       /* This is a chunk that was skipped due to failing the erased check */
+                               } else 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 {
+                                       if (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING ||
+                                           state == YAFFS_BLOCK_STATE_ALLOCATING) {
+                                               if (dev->seq_number == bi->seq_number) {
+                                                       /* this is the block being allocated from */
+
+                                                       T(YAFFS_TRACE_SCAN,
+                                                         (TSTR
+                                                          (" Allocating from %d %d"
+                                                           TENDSTR), blk, c));
+
+                                                       state = YAFFS_BLOCK_STATE_ALLOCATING;
+                                                       dev->alloc_block = blk;
+                                                       dev->alloc_page = c;
+                                                       dev->alloc_block_finder = blk;
+                                               } else {
+                                                       /* This is a partially written block that is not
+                                                        * the current allocation block.
+                                                        */
+
+                                                        T(YAFFS_TRACE_SCAN,
+                                                        (TSTR("Partially written block %d detected" TENDSTR),
+                                                        blk));
+                                               }
+                                       }
+                               }
+
+                               dev->n_free_chunks++;
+
+                       } else if (tags.ecc_result == YAFFS_ECC_RESULT_UNFIXED) {
+                               T(YAFFS_TRACE_SCAN,
+                                 (TSTR(" Unfixed ECC in chunk(%d:%d), chunk ignored"TENDSTR),
+                                 blk, c));
+
+                                 dev->n_free_chunks++;
+
+                       } else if (tags.obj_id > YAFFS_MAX_OBJECT_ID ||
+                               tags.chunk_id > YAFFS_MAX_CHUNK_ID ||
+                               (tags.chunk_id > 0 && tags.n_bytes > dev->data_bytes_per_chunk) ||
+                               tags.seq_number != bi->seq_number ) {
+                               T(YAFFS_TRACE_SCAN,
+                                 (TSTR("Chunk (%d:%d) with bad tags:obj = %d, chunk_id = %d, n_bytes = %d, ignored"TENDSTR),
+                                 blk, c,tags.obj_id, tags.chunk_id, tags.n_bytes));
+
+                                 dev->n_free_chunks++;
+
+                       } else if (tags.chunk_id > 0) {
+                               /* chunk_id > 0 so it is a data chunk... */
+                               unsigned int endpos;
+                               __u32 chunkBase =
+                                   (tags.chunk_id - 1) * dev->data_bytes_per_chunk;
+
+                               foundChunksInBlock = 1;
+
+
+                               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);
+                               if (!in) {
+                                       /* Out of memory */
+                                       alloc_failed = 1;
+                               }
+
+                               if (in &&
+                                   in->variant_type == YAFFS_OBJECT_TYPE_FILE
+                                   && chunkBase < in->variant.file_variant.shrink_size) {
+                                       /* This has not been invalidated by a resize */
+                                       if (!yaffs_put_chunk_in_file(in, tags.chunk_id, chunk, -1)) {
+                                               alloc_failed = 1;
+                                       }
+
+                                       /* File size is calculated by looking at the data chunks if we have not
+                                        * seen an object header yet. Stop this practice once we find an object header.
+                                        */
+                                       endpos = chunkBase + tags.n_bytes;
+
+                                       if (!in->valid &&       /* have not got an object header yet */
+                                           in->variant.file_variant.scanned_size < endpos) {
+                                               in->variant.file_variant.scanned_size = endpos;
+                                               in->variant.file_variant.file_size = endpos;
+                                       }
+
+                               } else if (in) {
+                                       /* This chunk has been invalidated by a resize, or a past file deletion
+                                        * so delete the chunk*/
+                                       yaffs_chunk_del(dev, chunk, 1, __LINE__);
+
+                               }
+                       } else {
+                               /* chunk_id == 0, so it is an ObjectHeader.
+                                * Thus, we read in the object header and make the object
+                                */
+                               foundChunksInBlock = 1;
+
+                               yaffs_set_chunk_bit(dev, blk, c);
+                               bi->pages_in_use++;
+
+                               oh = NULL;
+                               in = NULL;
+
+                               if (tags.extra_available) {
+                                       in = yaffs_find_or_create_by_number(dev,
+                                               tags.obj_id,
+                                               tags.extra_obj_type);
+                                       if (!in)
+                                               alloc_failed = 1;
+                               }
+
+                               if (!in ||
+                                   (!in->valid && dev->param.disable_lazy_load) ||
+                                   tags.extra_shadows ||
+                                   (!in->valid &&
+                                   (tags.obj_id == YAFFS_OBJECTID_ROOT ||
+                                    tags.obj_id == YAFFS_OBJECTID_LOSTNFOUND))) {
+
+                                       /* If we don't have  valid info then we need to read the chunk
+                                        * TODO In future we can probably defer reading the chunk and
+                                        * living with invalid data until needed.
+                                        */
+
+                                       result = yaffs_rd_chunk_tags_nand(dev,
+                                                                       chunk,
+                                                                       chunkData,
+                                                                       NULL);
+
+                                       oh = (yaffs_obj_header *) chunkData;
+
+                                       if (dev->param.inband_tags) {
+                                               /* Fix up the header if they got corrupted by inband tags */
+                                               oh->shadows_obj = oh->inband_shadowed_obj_id;
+                                               oh->is_shrink = oh->inband_is_shrink;
+                                       }
+
+                                       if (!in) {
+                                               in = yaffs_find_or_create_by_number(dev, tags.obj_id, oh->type);
+                                               if (!in)
+                                                       alloc_failed = 1;
+                                       }
+
+                               }
+
+                               if (!in) {
+                                       /* TODO Hoosterman we have a problem! */
+                                       T(YAFFS_TRACE_ERROR,
+                                         (TSTR
+                                          ("yaffs tragedy: Could not make object for object  %d at chunk %d during scan"
+                                           TENDSTR), tags.obj_id, chunk));
+                                       continue;
+                               }
+
+                               if (in->valid) {
+                                       /* We have already filled this one.
+                                        * We have a duplicate that will be discarded, but
+                                        * we first have to suck out resize info if it is a file.
+                                        */
+
+                                       if ((in->variant_type == YAFFS_OBJECT_TYPE_FILE) &&
+                                            ((oh &&
+                                              oh->type == YAFFS_OBJECT_TYPE_FILE) ||
+                                             (tags.extra_available  &&
+                                              tags.extra_obj_type == YAFFS_OBJECT_TYPE_FILE))) {
+                                               __u32 thisSize =
+                                                   (oh) ? oh->file_size : tags.
+                                                   extra_length;
+                                               __u32 parent_obj_id =
+                                                   (oh) ? oh->
+                                                   parent_obj_id : tags.
+                                                   extra_parent_id;
+
+
+                                               is_shrink =
+                                                   (oh) ? oh->is_shrink : tags.
+                                                   extra_is_shrink;
+
+                                               /* If it is deleted (unlinked at start also means deleted)
+                                                * we treat the file size as being zeroed at this point.
+                                                */
+                                               if (parent_obj_id ==
+                                                   YAFFS_OBJECTID_DELETED
+                                                   || parent_obj_id ==
+                                                   YAFFS_OBJECTID_UNLINKED) {
+                                                       thisSize = 0;
+                                                       is_shrink = 1;
+                                               }
+
+                                               if (is_shrink && in->variant.file_variant.shrink_size > thisSize)
+                                                       in->variant.file_variant.shrink_size = thisSize;
+
+                                               if (is_shrink)
+                                                       bi->has_shrink_hdr = 1;
+
+                                       }
+                                       /* Use existing - destroy this one. */
+                                       yaffs_chunk_del(dev, chunk, 1, __LINE__);
+
+                               }
+
+                               if (!in->valid && in->variant_type !=
+                                   (oh ? oh->type : tags.extra_obj_type))
+                                       T(YAFFS_TRACE_ERROR, (
+                                               TSTR("yaffs tragedy: Bad object type, "
+                                           TCONT("%d != %d, for object %d at chunk ")
+                                           TCONT("%d during scan")
+                                               TENDSTR), oh ?
+                                           oh->type : tags.extra_obj_type,
+                                           in->variant_type, tags.obj_id,
+                                           chunk));
+
+                               if (!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;
+
+                                       if (oh) {
+
+                                               in->yst_mode = oh->yst_mode;
+#ifdef CONFIG_YAFFS_WINCE
+                                               in->win_atime[0] = oh->win_atime[0];
+                                               in->win_ctime[0] = oh->win_ctime[0];
+                                               in->win_mtime[0] = oh->win_mtime[0];
+                                               in->win_atime[1] = oh->win_atime[1];
+                                               in->win_ctime[1] = oh->win_ctime[1];
+                                               in->win_mtime[1] = oh->win_mtime[1];
+#else
+                                               in->yst_uid = oh->yst_uid;
+                                               in->yst_gid = oh->yst_gid;
+                                               in->yst_atime = oh->yst_atime;
+                                               in->yst_mtime = oh->yst_mtime;
+                                               in->yst_ctime = oh->yst_ctime;
+                                               in->yst_rdev = oh->yst_rdev;
+
+                                               in->lazy_loaded = 0;
+
+#endif
+                                       } else
+                                               in->lazy_loaded = 1;
+
+                                       in->hdr_chunk = chunk;
+
+                               } else if (!in->valid) {
+                                       /* we need to load this info */
+
+                                       in->valid = 1;
+                                       in->hdr_chunk = chunk;
+
+                                       if (oh) {
+                                               in->variant_type = oh->type;
+
+                                               in->yst_mode = oh->yst_mode;
+#ifdef CONFIG_YAFFS_WINCE
+                                               in->win_atime[0] = oh->win_atime[0];
+                                               in->win_ctime[0] = oh->win_ctime[0];
+                                               in->win_mtime[0] = oh->win_mtime[0];
+                                               in->win_atime[1] = oh->win_atime[1];
+                                               in->win_ctime[1] = oh->win_ctime[1];
+                                               in->win_mtime[1] = oh->win_mtime[1];
+#else
+                                               in->yst_uid = oh->yst_uid;
+                                               in->yst_gid = oh->yst_gid;
+                                               in->yst_atime = oh->yst_atime;
+                                               in->yst_mtime = oh->yst_mtime;
+                                               in->yst_ctime = oh->yst_ctime;
+                                               in->yst_rdev = oh->yst_rdev;
+#endif
+
+                                               if (oh->shadows_obj > 0)
+                                                       yaffs_handle_shadowed_obj(dev,
+                                                                          oh->
+                                                                          shadows_obj,
+                                                                          1);
+                                                       
+
+
+                                               yaffs_set_obj_name_from_oh(in, oh);
+                                               parent =
+                                                   yaffs_find_or_create_by_number
+                                                       (dev, oh->parent_obj_id,
+                                                        YAFFS_OBJECT_TYPE_DIRECTORY);
+
+                                                file_size = oh->file_size;
+                                                is_shrink = oh->is_shrink;
+                                                equiv_id = oh->equiv_id;
+
+                                       } else {
+                                               in->variant_type = tags.extra_obj_type;
+                                               parent =
+                                                   yaffs_find_or_create_by_number
+                                                       (dev, tags.extra_parent_id,
+                                                        YAFFS_OBJECT_TYPE_DIRECTORY);
+                                                file_size = tags.extra_length;
+                                                is_shrink = tags.extra_is_shrink;
+                                                equiv_id = tags.extra_equiv_id;
+                                               in->lazy_loaded = 1;
+
+                                       }
+                                       in->dirty = 0;
+
+                                       if (!parent)
+                                               alloc_failed = 1;
+
+                                       /* directory stuff...
+                                        * hook up to parent
+                                        */
+
+                                       if (parent && parent->variant_type ==
+                                           YAFFS_OBJECT_TYPE_UNKNOWN) {
+                                               /* Set up as a directory */
+                                               parent->variant_type =
+                                                       YAFFS_OBJECT_TYPE_DIRECTORY;
+                                               YINIT_LIST_HEAD(&parent->variant.
+                                                       dir_variant.
+                                                       children);
+                                       } else if (!parent || parent->variant_type !=
+                                                  YAFFS_OBJECT_TYPE_DIRECTORY) {
+                                               /* Hoosterman, another problem....
+                                                * We're trying to use a non-directory as a directory
+                                                */
+
+                                               T(YAFFS_TRACE_ERROR,
+                                                 (TSTR
+                                                  ("yaffs tragedy: attempting to use non-directory as a directory in scan. Put in lost+found."
+                                                   TENDSTR)));
+                                               parent = dev->lost_n_found;
+                                       }
+
+                                       yaffs_add_obj_to_dir(parent, in);
+
+                                       itsUnlinked = (parent == dev->del_dir) ||
+                                                     (parent == dev->unlinked_dir);
+
+                                       if (is_shrink) {
+                                               /* Mark the block as having a shrinkHeader */
+                                               bi->has_shrink_hdr = 1;
+                                       }
+
+                                       /* Note re hardlinks.
+                                        * Since we might scan a hardlink before its equivalent object is scanned
+                                        * we put them all in a list.
+                                        * After scanning is complete, we should have all the objects, so we run
+                                        * through this list and fix up all the chains.
+                                        */
+
+                                       switch (in->variant_type) {
+                                       case YAFFS_OBJECT_TYPE_UNKNOWN:
+                                               /* Todo got a problem */
+                                               break;
+                                       case YAFFS_OBJECT_TYPE_FILE:
+
+                                               if (in->variant.file_variant.
+                                                   scanned_size < file_size) {
+                                                       /* This covers the case where the file size is greater
+                                                        * than where the data is
+                                                        * This will happen if the file is resized to be larger
+                                                        * than its current data extents.
+                                                        */
+                                                       in->variant.file_variant.file_size = file_size;
+                                                       in->variant.file_variant.scanned_size = file_size;
+                                               }
+
+                                               if (in->variant.file_variant.shrink_size > file_size)
+                                                       in->variant.file_variant.shrink_size = file_size;
+                               
+
+                                               break;
+                                       case YAFFS_OBJECT_TYPE_HARDLINK:
+                                               if (!itsUnlinked) {
+                                                       in->variant.hardlink_variant.equiv_id =
+                                                               equiv_id;
+                                                       in->hard_links.next =
+                                                               (struct ylist_head *) hard_list;
+                                                       hard_list = in;
+                                               }
+                                               break;
+                                       case YAFFS_OBJECT_TYPE_DIRECTORY:
+                                               /* Do nothing */
+                                               break;
+                                       case YAFFS_OBJECT_TYPE_SPECIAL:
+                                               /* Do nothing */
+                                               break;
+                                       case YAFFS_OBJECT_TYPE_SYMLINK:
+                                               if (oh) {
+                                                       in->variant.symlink_variant.alias =
+                                                               yaffs_clone_str(oh->alias);
+                                                       if (!in->variant.symlink_variant.alias)
+                                                               alloc_failed = 1;
+                                               }
+                                               break;
+                                       }
+
+                               }
+
+                       }
+
+               } /* End of scanning for each chunk */
+
+               if (state == YAFFS_BLOCK_STATE_NEEDS_SCANNING) {
+                       /* If we got this far while scanning, then the block is fully allocated. */
+                       state = YAFFS_BLOCK_STATE_FULL;
+               }
+
+
+               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);
+               }
+
+       }
+       
+       yaffs_skip_rest_of_block(dev);
+
+       if (altBlockIndex)
+               YFREE_ALT(blockIndex);
+       else
+               YFREE(blockIndex);
+
+       /* 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);
+
+
+       yaffs_release_temp_buffer(dev, chunkData, __LINE__);
+
+       if (alloc_failed)
+               return YAFFS_FAIL;
+
+       T(YAFFS_TRACE_SCAN, (TSTR("yaffs2_scan_backwards ends" TENDSTR)));
+
+       return YAFFS_OK;
+}