Add qemu 2.4.0
[kvmfornfv.git] / qemu / roms / u-boot / fs / yaffs2 / yaffs_guts.c
diff --git a/qemu/roms/u-boot/fs/yaffs2/yaffs_guts.c b/qemu/roms/u-boot/fs/yaffs2/yaffs_guts.c
new file mode 100644 (file)
index 0000000..21441fd
--- /dev/null
@@ -0,0 +1,5021 @@
+/*
+ * 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 "yportenv.h"
+#include "yaffs_trace.h"
+
+#include "yaffs_guts.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"
+#include "yaffs_summary.h"
+
+/* Note YAFFS_GC_GOOD_ENOUGH must be <= YAFFS_GC_PASSIVE_THRESHOLD */
+#define YAFFS_GC_GOOD_ENOUGH 2
+#define YAFFS_GC_PASSIVE_THRESHOLD 4
+
+#include "yaffs_ecc.h"
+
+/* Forward declarations */
+
+static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
+                            const u8 *buffer, int n_bytes, int use_reserve);
+
+
+
+/* Function to calculate chunk and offset */
+
+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) {
+               /* easy power of 2 case */
+               offset = (u32) (addr & dev->chunk_mask);
+       } else {
+               /* Non power-of-2 case */
+
+               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;
+}
+
+/* Function to return the number of shifts for a power of 2 greater than or
+ * equal to the given number
+ * Note we don't try to cater for all possible numbers and this does not have to
+ * be hellishly efficient.
+ */
+
+static inline 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;
+}
+
+/* Function to return the number of shifts to get a 1 in bit 0
+ */
+
+static inline u32 calc_shifts(u32 x)
+{
+       u32 shifts;
+
+       shifts = 0;
+
+       if (!x)
+               return 0;
+
+       while (!(x & 1)) {
+               x >>= 1;
+               shifts++;
+       }
+
+       return shifts;
+}
+
+/*
+ * Temporary buffer manipulations.
+ */
+
+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].in_use = 0;
+               buf = kmalloc(dev->param.total_bytes_per_chunk, GFP_NOFS);
+               dev->temp_buffer[i].buffer = buf;
+       }
+
+       return buf ? YAFFS_OK : YAFFS_FAIL;
+}
+
+u8 *yaffs_get_temp_buffer(struct yaffs_dev * dev)
+{
+       int i;
+
+       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].in_use == 0) {
+                       dev->temp_buffer[i].in_use = 1;
+                       return dev->temp_buffer[i].buffer;
+               }
+       }
+
+       yaffs_trace(YAFFS_TRACE_BUFFERS, "Out of temp buffers");
+       /*
+        * If we got here then we have to allocate an unmanaged one
+        * This is not good.
+        */
+
+       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 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].in_use = 0;
+                       return;
+               }
+       }
+
+       if (buffer) {
+               /* assume it is an unmanaged one. */
+               yaffs_trace(YAFFS_TRACE_BUFFERS,
+                       "Releasing unmanaged temp buffer");
+               kfree(buffer);
+               dev->unmanaged_buffer_deallocs++;
+       }
+
+}
+
+/*
+ * Determine if we have a managed buffer.
+ */
+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;
+}
+
+/*
+ * Functions for robustisizing TODO
+ *
+ */
+
+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; /* Too many stikes, so retire */
+                       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) {
+               /* Was an actual write failure,
+                * so mark the block for retirement.*/
+               bi->needs_retiring = 1;
+               yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
+                 "**>> Block %d needs retiring", flash_block);
+       }
+
+       /* Delete the chunk */
+       yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
+       yaffs_skip_rest_of_block(dev);
+}
+
+/*
+ * Verification code
+ */
+
+/*
+ *  Simple hash function. Needs to have a reasonable spread
+ */
+
+static inline int yaffs_hash_fn(int n)
+{
+       if (n < 0)
+               n = -n;
+       return n % YAFFS_NOBJECT_BUCKETS;
+}
+
+/*
+ * Access functions to useful fake objects.
+ * Note that root might have a presence in NAND if permissions are set.
+ */
+
+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;
+}
+
+/*
+ *  Erased NAND checking functions
+ */
+
+int yaffs_check_ff(u8 *buffer, int n_bytes)
+{
+       /* Horrible, slow implementation */
+       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);
+       struct yaffs_ext_tags tags;
+
+       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);
+
+       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);
+
+       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);
+
+       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) {
+               /* Hoosterman we've got a problem.
+                * Can't get space to gc
+                */
+               yaffs_trace(YAFFS_TRACE_ERROR,
+                 "yaffs tragedy: no more erased blocks");
+
+               return -1;
+       }
+
+       /* Find an empty block. */
+
+       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) {
+               /* Get next block to allocate off */
+               dev->alloc_block = yaffs_find_alloc_block(dev);
+               dev->alloc_page = 0;
+       }
+
+       if (!use_reserver && !yaffs_check_alloc_available(dev, 1)) {
+               /* No space unless we're allowed to use the reserve. */
+               return -1;
+       }
+
+       if (dev->n_erased_blocks < dev->param.n_reserved_blocks
+           && dev->alloc_page == 0)
+               yaffs_trace(YAFFS_TRACE_ALLOCATE, "Allocating reserve");
+
+       /* Next page please.... */
+       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 the block is full set the state to full */
+               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;
+
+}
+
+/*
+ * yaffs_skip_rest_of_block() skips over the rest of the allocation block
+ * if we don't want to write to it.
+ */
+void yaffs_skip_rest_of_block(struct yaffs_dev *dev)
+{
+       struct yaffs_block_info *bi;
+
+       if (dev->alloc_block > 0) {
+               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) {
+                       /* no space */
+                       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.
+                */
+
+               /* let's give it a try */
+               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);
+
+                               /* If not erased, delete this one,
+                                * skip rest of block and
+                                * try another 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) {
+                       /* Clean up aborted write, skip to next block and
+                        * try another chunk */
+                       yaffs_handle_chunk_wr_error(dev, chunk, erased_ok);
+                       continue;
+               }
+
+               bi->skip_erased_check = 1;
+
+               /* Copy the data into the robustification buffer */
+               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_retried_writes += (attempts - 1);
+       }
+
+       return chunk;
+}
+
+/*
+ * Block retiring for handling a broken block.
+ */
+
+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);
+
+                       memset(buffer, 0xff, dev->data_bytes_per_chunk);
+                       memset(&tags, 0, sizeof(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);
+               }
+       }
+
+       bi->block_state = YAFFS_BLOCK_STATE_DEAD;
+       bi->gc_prioritise = 0;
+       bi->needs_retiring = 0;
+
+       dev->n_retired_blocks++;
+}
+
+/*---------------- Name handling functions ------------*/
+
+static u16 yaffs_calc_name_sum(const YCHAR *name)
+{
+       u16 sum = 0;
+       u16 i = 1;
+
+       if (!name)
+               return 0;
+
+       while ((*name) && i < (YAFFS_MAX_NAME_LENGTH / 2)) {
+
+               /* 0x1f mask is case insensitive */
+               sum += ((*name) & 0x1f) * i;
+               i++;
+               name++;
+       }
+       return sum;
+}
+
+void yaffs_set_obj_name(struct yaffs_obj *obj, const YCHAR * name)
+{
+       memset(obj->short_name, 0, sizeof(obj->short_name));
+       if (name &&
+               yaffs_strnlen(name, YAFFS_SHORT_NAME_LENGTH + 1) <=
+               YAFFS_SHORT_NAME_LENGTH)
+               yaffs_strcpy(obj->short_name, name);
+       else
+               obj->short_name[0] = _Y('\0');
+       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
+}
+
+loff_t yaffs_max_file_size(struct yaffs_dev *dev)
+{
+       return ((loff_t) YAFFS_MAX_CHUNK_ID) * dev->data_bytes_per_chunk;
+}
+
+/*-------------------- TNODES -------------------
+
+ * List of spare tnodes
+ * The list is hooked together using the first pointer
+ * in the tnode.
+ */
+
+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;    /* force recalculation */
+
+       return tn;
+}
+
+/* FreeTnode frees up a tnode and puts it back on the free list */
+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;    /* force recalculation */
+}
+
+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;
+}
+
+/* ------------------- End of individual tnode manipulation -----------------*/
+
+/* ---------Functions to manipulate the look-up tree (made up of tnodes) ------
+ * The look up tree is represented by the top tnode and the number of top_level
+ * in the tree. 0 means only the level 0 tnode is in the tree.
+ */
+
+/* FindLevel0Tnode finds the level 0 tnode, if one exists. */
+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;
+
+       /* Check sane level and chunk Id */
+       if (level < 0 || level > YAFFS_TNODES_MAX_LEVEL)
+               return NULL;
+
+       if (chunk_id > YAFFS_MAX_CHUNK_ID)
+               return NULL;
+
+       /* First check we're tall enough (ie enough top_level) */
+
+       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;    /* Not tall enough, so we can't find it */
+
+       /* Traverse down to level 0 */
+       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;
+}
+
+/* add_find_tnode_0 finds the level 0 tnode if it exists,
+ * otherwise first expands the tree.
+ * This happens in two steps:
+ *  1. If the tree isn't tall enough, then make it taller.
+ *  2. Scan down the tree towards the level 0 tnode adding tnodes if required.
+ *
+ * Used when modifying the tree.
+ *
+ *  If the tn argument is NULL, then a fresh tnode will be added otherwise the
+ *  specified tn will be plugged into the ttree.
+ */
+
+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;
+
+       /* Check sane level and page Id */
+       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;
+
+       /* First check we're tall enough (ie enough top_level) */
+
+       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) {
+               /* Not tall enough, gotta make the tree taller */
+               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;
+                       }
+               }
+       }
+
+       /* Traverse down to level 0, adding anything we need */
+
+       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]) {
+                               /* Add missing non-level-zero tnode */
+                               tn->internal[x] = yaffs_get_tnode(dev);
+                               if (!tn->internal[x])
+                                       return NULL;
+                       } else if (l == 1) {
+                               /* Looking from level 1 at level 0 */
+                               if (passed_tn) {
+                                       /* If we already have one, release it */
+                                       if (tn->internal[x])
+                                               yaffs_free_tnode(dev,
+                                                       tn->internal[x]);
+                                       tn->internal[x] = passed_tn;
+
+                               } else if (!tn->internal[x]) {
+                                       /* Don't have one, none passed in */
+                                       tn->internal[x] = yaffs_get_tnode(dev);
+                                       if (!tn->internal[x])
+                                               return NULL;
+                               }
+                       }
+
+                       tn = tn->internal[x];
+                       l--;
+               }
+       } else {
+               /* top is level 0 */
+               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)) {
+                                       /* found it; */
+                                       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)
+{
+       /*Get the Tnode, then get the level 0 offset chunk offset */
+       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) {
+               /* Passed a NULL, so use our own tags space */
+               tags = &local_tags;
+       }
+
+       tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);
+
+       if (!tn)
+               return ret_val;
+
+       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)
+{
+       /* Get the Tnode, then get the level 0 offset chunk offset */
+       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) {
+               /* Passed a NULL, so use our own tags space */
+               tags = &local_tags;
+       }
+
+       tn = yaffs_find_tnode_0(dev, &in->variant.file_variant, inode_chunk);
+
+       if (!tn)
+               return ret_val;
+
+       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);
+
+       /* Delete the entry in the filestructure (if found) */
+       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)
+{
+       /* NB in_scan is zero unless scanning.
+        * For forward scanning, in_scan is > 0;
+        * for backward scanning in_scan is < 0
+        *
+        * nand_chunk = 0 is a dummy insert to make sure the tnodes are there.
+        */
+
+       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) {
+               /* Just ignore an attempt at putting a chunk into a non-file
+                * during scanning.
+                * If it is not during Scanning then something went wrong!
+                */
+               if (!in_scan) {
+                       yaffs_trace(YAFFS_TRACE_ERROR,
+                               "yaffs tragedy:attempt to put data chunk into a non-file"
+                               );
+                       BUG();
+               }
+
+               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)
+               /* Dummy insert, bail now */
+               return YAFFS_OK;
+
+       existing_cunk = yaffs_get_group_base(dev, tn, inode_chunk);
+
+       if (in_scan != 0) {
+               /* If we're scanning then we need to test for duplicates
+                * NB This does not need to be efficient since it should only
+                * happen when the power fails during a write, then only one
+                * chunk should ever be affected.
+                *
+                * Correction for YAFFS2: This could happen quite a lot and we
+                * need to think about efficiency! TODO
+                * Update: For backward scanning we don't need to re-read tags
+                * so this is quite cheap.
+                */
+
+               if (existing_cunk > 0) {
+                       /* NB Right now existing chunk will not be real
+                        * chunk_id if the chunk group size > 1
+                        * thus we have to do a FindChunkInFile to get the
+                        * real chunk id.
+                        *
+                        * We have a duplicate now we need to decide which
+                        * one to use:
+                        *
+                        * Backwards scanning YAFFS2: The old one is what
+                        * we use, dump the new one.
+                        * YAFFS1: Get both sets of tags and compare serial
+                        * numbers.
+                        */
+
+                       if (in_scan > 0) {
+                               /* Only do this for forward scanning */
+                               yaffs_rd_chunk_tags_nand(dev,
+                                                        nand_chunk,
+                                                        NULL, &new_tags);
+
+                               /* Do a proper find */
+                               existing_cunk =
+                                   yaffs_find_chunk_in_file(in, inode_chunk,
+                                                            &existing_tags);
+                       }
+
+                       if (existing_cunk <= 0) {
+                               /*Hoosterman - how did this happen? */
+
+                               yaffs_trace(YAFFS_TRACE_ERROR,
+                                       "yaffs tragedy: existing chunk < 0 in scan"
+                                       );
+
+                       }
+
+                       /* NB The deleted flags should be false, otherwise
+                        * the chunks will not be loaded during a 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)) {
+                               /* Forward scanning.
+                                * Use new
+                                * Delete the old one and drop through to
+                                * update the tnode
+                                */
+                               yaffs_chunk_del(dev, existing_cunk, 1,
+                                               __LINE__);
+                       } else {
+                               /* Backward scanning or we want to use the
+                                * existing one
+                                * Delete the new one and return early so that
+                                * the tnode isn't changed
+                                */
+                               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);
+       }
+}
+
+/* SoftDeleteWorker scans backwards through the tnode tree and soft deletes all
+ * the chunks in the file.
+ * All soft deleting does is increment the block's softdelete count and pulls
+ * the chunk out of the tnode.
+ * Thus, essentially this is the same as DeleteWorker except that the chunks
+ * are soft deleted.
+ */
+
+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)
+               return 1;
+
+       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 {
+                                       /* Can this happen? */
+                               }
+                       }
+               }
+               return (all_done) ? 1 : 0;
+       }
+
+       /* 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;
+}
+
+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"
+                       );
+               BUG();
+               return;
+       }
+       if (directory->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
+               yaffs_trace(YAFFS_TRACE_ALWAYS,
+                       "tragedy: Trying to add an object to a non-directory"
+                       );
+               BUG();
+       }
+
+       if (obj->siblings.prev == NULL) {
+               /* Not initialised */
+               BUG();
+       }
+
+       yaffs_verify_dir(directory);
+
+       yaffs_remove_obj_from_dir(obj);
+
+       /* Now add it */
+       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;  /* use the old directory */
+
+       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"
+                       );
+               BUG();
+       }
+
+       unlink_op = (new_dir == obj->my_dev->unlinked_dir);
+       del_op = (new_dir == obj->my_dev->del_dir);
+
+       existing_target = yaffs_find_by_name(new_dir, new_name);
+
+       /* If the object is a file going into the unlinked directory,
+        *   then it is OK to just stuff it in since duplicate names are OK.
+        *   else only proceed if the new name does not exist and we're putting
+        *   it into a directory.
+        */
+       if (!(unlink_op || del_op || force ||
+             shadows > 0 || !existing_target) ||
+             new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY)
+               return YAFFS_FAIL;
+
+       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 it is a deletion then we mark it as a shrink for gc  */
+       if (yaffs_update_oh(obj, new_name, 0, del_op, shadows, NULL) >= 0)
+               return YAFFS_OK;
+
+       return YAFFS_FAIL;
+}
+
+/*------------------------ Short Operations Cache ------------------------------
+ *   In many situations where there is no high level buffering  a lot of
+ *   reads might be short sequential reads, and a lot of writes may be short
+ *   sequential writes. eg. scanning/writing a jpeg file.
+ *   In these cases, a short read/write cache can provide a huge perfomance
+ *   benefit with dumb-as-a-rock code.
+ *   In Linux, the page cache provides read buffering and the short op cache
+ *   provides write buffering.
+ *
+ *   There are a small number (~10) of cache chunks per device so that we don't
+ *   need a very intelligent search.
+ */
+
+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;       /* Stop compiler whining. */
+       int i;
+       struct yaffs_cache *cache;
+       int chunk_written = 0;
+       int n_caches = obj->my_dev->param.n_caches;
+
+       if (n_caches < 1)
+               return;
+       do {
+               cache = NULL;
+
+               /* Find the lowest dirty chunk for this object */
+               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) {
+                       /* Write it out and free it up */
+                       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)
+               /* Hoosterman, disk full while writing cache out. */
+               yaffs_trace(YAFFS_TRACE_ERROR,
+                       "yaffs tragedy: no space during cache write");
+}
+
+/*yaffs_flush_whole_cache(dev)
+ *
+ *
+ */
+
+void yaffs_flush_whole_cache(struct yaffs_dev *dev)
+{
+       struct yaffs_obj *obj;
+       int n_caches = dev->param.n_caches;
+       int i;
+
+       /* Find a dirty object in the cache and flush it...
+        * until there are no further dirty objects.
+        */
+       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);
+
+}
+
+/* Grab us a cache chunk for use.
+ * First look for an empty one.
+ * Then look for the least recently used non-dirty one.
+ * Then look for the least recently used dirty one...., flush and look again.
+ */
+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;
+
+       if (dev->param.n_caches < 1)
+               return NULL;
+
+       /* Try find a non-dirty one... */
+
+       cache = yaffs_grab_chunk_worker(dev);
+
+       if (!cache) {
+               /* They were all dirty, find the LRU object and flush
+                * its cache, then  find again.
+                * NB what's here is not very accurate,
+                * we actually flush the object with the LRU chunk.
+                */
+
+               /* With locking we can't assume we can use entry zero,
+                * Set the_obj to a valid pointer for Coverity. */
+               the_obj = dev->cache[0].object;
+               usage = -1;
+               cache = NULL;
+
+               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];
+                       }
+               }
+
+               if (!cache || cache->dirty) {
+                       /* Flush and try again */
+                       yaffs_flush_file_cache(the_obj);
+                       cache = yaffs_grab_chunk_worker(dev);
+               }
+       }
+       return cache;
+}
+
+/* Find a cached chunk */
+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 < 1)
+               return NULL;
+
+       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;
+}
+
+/* Mark the chunk for the least recently used algorithym */
+static void yaffs_use_cache(struct yaffs_dev *dev, struct yaffs_cache *cache,
+                           int is_write)
+{
+       int i;
+
+       if (dev->param.n_caches < 1)
+               return;
+
+       if (dev->cache_last_use < 0 ||
+               dev->cache_last_use > 100000000) {
+               /* Reset the cache usages */
+               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)
+{
+       struct yaffs_cache *cache;
+
+       if (object->my_dev->param.n_caches > 0) {
+               cache = yaffs_find_chunk_cache(object, chunk_id);
+
+               if (cache)
+                       cache->object = NULL;
+       }
+}
+
+/* Invalidate all the cache pages associated with this object
+ * Do this whenever ther file is deleted or resized.
+ */
+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) {
+               /* Invalidate it. */
+               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 it is still linked into the bucket list, free from the list */
+       if (!list_empty(&obj->hash_link)) {
+               list_del_init(&obj->hash_link);
+               bucket = yaffs_hash_fn(obj->obj_id);
+               dev->obj_bucket[bucket].count--;
+       }
+}
+
+/*  FreeObject frees up a Object and puts it back on the free list */
+static void yaffs_free_obj(struct yaffs_obj *obj)
+{
+       struct yaffs_dev *dev;
+
+       if (!obj) {
+               BUG();
+               return;
+       }
+       dev = obj->my_dev;
+       yaffs_trace(YAFFS_TRACE_OS, "FreeObject %p inode %p",
+               obj, obj->my_inode);
+       if (obj->parent)
+               BUG();
+       if (!list_empty(&obj->siblings))
+               BUG();
+
+       if (obj->my_inode) {
+               /* We're still hooked up to a cached inode.
+                * Don't delete now, but mark for later deletion
+                */
+               obj->defered_free = 1;
+               return;
+       }
+
+       yaffs_unhash_obj(obj);
+
+       yaffs_free_raw_obj(dev, obj);
+       dev->n_obj--;
+       dev->checkpoint_blocks_required = 0;    /* force recalculation */
+}
+
+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)
+{
+       /* Iinvalidate the file's data in the cache, without flushing. */
+       yaffs_invalidate_whole_cache(in);
+
+       if (in->my_dev->param.is_yaffs2 && in->parent != in->my_dev->del_dir) {
+               /* Move to unlinked directory so we have a deletion record */
+               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)
+               return;
+
+       if (obj->n_data_chunks <= 0) {
+               /* Empty file with no duplicate object headers,
+                * just delete it immediately */
+               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;
+       }
+}
+
+/* Pruning removes any part of the file structure tree that is beyond the
+ * bounds of the file (ie that does not point to chunks).
+ *
+ * A file should only get pruned when its size is reduced.
+ *
+ * Before pruning, the chunks must be pulled from the tree and the
+ * level 0 tnode entries must be zeroed out.
+ * Could also use this for file deletion, but that's probably better handled
+ * by a special case.
+ *
+ * This function is recursive. For levels > 0 the function is called again on
+ * any sub-tree. For level == 0 we just check if the sub-tree has data.
+ * If there is no data in a subtree then it is pruned.
+ */
+
+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)
+               return 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) {
+               /* Free and return NULL */
+               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 < 1)
+               return YAFFS_OK;
+
+       file_struct->top =
+          yaffs_prune_worker(dev, file_struct->top, file_struct->top_level, 0);
+
+       /* Now we have a tree with all the non-zero branches NULL but
+        * the height is the same as it was.
+        * Let's see if we can trim internal tnodes to shorten the tree.
+        * We can do this if only the 0th element in the tnode is in use
+        * (ie all the non-zero are NULL)
+        */
+
+       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;
+}
+
+/*-------------------- End of File Structure functions.-------------------*/
+
+/* alloc_empty_obj gets us a clean Object.*/
+static struct yaffs_obj *yaffs_alloc_empty_obj(struct yaffs_dev *dev)
+{
+       struct yaffs_obj *obj = yaffs_alloc_raw_obj(dev);
+
+       if (!obj)
+               return obj;
+
+       dev->n_obj++;
+
+       /* Now sweeten it up... */
+
+       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);
+
+       /* Now make the directory sane */
+       if (dev->root_dir) {
+               obj->parent = dev->root_dir;
+               list_add(&(obj->siblings),
+                        &dev->root_dir->variant.dir_variant.children);
+       }
+
+       /* Add it to the lost and found directory.
+        * NB Can't put root or lost-n-found in lost-n-found so
+        * check if lost-n-found exists first
+        */
+       if (dev->lost_n_found)
+               yaffs_add_obj_to_dir(dev->lost_n_found, obj);
+
+       obj->being_created = 0;
+
+       dev->checkpoint_blocks_required = 0;    /* force recalculation */
+
+       return obj;
+}
+
+static int yaffs_find_nice_bucket(struct yaffs_dev *dev)
+{
+       int i;
+       int l = 999;
+       int lowest = 999999;
+
+       /* Search for the shortest list or one that
+        * isn't too long.
+        */
+
+       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;
+
+       /* Now find an object value that has not already been taken
+        * by scanning the list.
+        */
+
+       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 there is already one in the 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) {
+               /* Look if it is in the list */
+               in = list_entry(i, struct yaffs_obj, hash_link);
+               if (in->obj_id == number) {
+                       /* Don't show if it is defered free */
+                       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;
+       }
+
+       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 =
+                                               yaffs_max_file_size(dev);
+               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:
+               /* No action required */
+               break;
+       case YAFFS_OBJECT_TYPE_UNKNOWN:
+               /* todo this should not happen */
+               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)
+               return NULL;
+
+       obj->fake = 1;  /* it is fake so it might not use NAND */
+       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;     /* Not a valid chunk. */
+       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 = yaffs_strnlen(str, YAFFS_MAX_ALIAS_LENGTH);
+       new_str = kmalloc((len + 1) * sizeof(YCHAR), GFP_NOFS);
+       if (new_str) {
+               yaffs_strncpy(new_str, str, len);
+               new_str[len] = 0;
+       }
+       return new_str;
+
+}
+/*
+ *yaffs_update_parent() handles fixing a directories mtime and ctime when a new
+ * link (ie. name) is created or deleted in the directory.
+ *
+ * ie.
+ *   create dir/a : update dir's mtime/ctime
+ *   rm dir/a:   update dir's mtime/ctime
+ *   modify dir/a: don't update dir's mtimme/ctime
+ *
+ * This can be handled immediately or defered. Defering helps reduce the number
+ * of updates when many files in a directory are changed within a brief period.
+ *
+ * If the directory updating is defered then yaffs_update_dirty_dirs must be
+ * called periodically.
+ */
+
+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);
+       }
+}
+
+/*
+ * Mknod (create) a new object.
+ * equiv_obj only has meaning for a hard link;
+ * alias_str only has meaning for a symlink.
+ * rdev only has meaning for devices (a subset of special objects)
+ */
+
+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;
+
+       /* Check if the entry exists.
+        * If it does then fail the call since we don't want a dup. */
+       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) {
+               kfree(str);
+               return NULL;
+       }
+
+       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:
+               /* do nothing */
+               break;
+       }
+
+       if (yaffs_update_oh(in, name, 0, 0, 0, NULL) < 0) {
+               /* Could not create the object header, fail */
+               yaffs_del_obj(in);
+               in = NULL;
+       }
+
+       if (in)
+               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);
+}
+
+/* yaffs_link_obj returns the object id of the equivalent object.*/
+struct yaffs_obj *yaffs_link_obj(struct yaffs_obj *parent, const YCHAR * name,
+                                struct yaffs_obj *equiv_obj)
+{
+       /* Get the real object in case we were fed a hard link 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;
+
+       return NULL;
+
+}
+
+
+
+/*---------------------- Block Management and Page Allocation -------------*/
+
+static void yaffs_deinit_blocks(struct yaffs_dev *dev)
+{
+       if (dev->block_info_alt && dev->block_info)
+               vfree(dev->block_info);
+       else
+               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
+               kfree(dev->chunk_bits);
+       dev->chunk_bits_alt = 0;
+       dev->chunk_bits = 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;  /* force it to get a new one */
+
+       /* If the first allocation strategy fails, thry the alternate one */
+       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)
+               goto alloc_error;
+
+       /* Set up dynamic blockinfo stuff. Round up bytes. */
+       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->chunk_bits)
+               goto alloc_error;
+
+
+       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;
+
+alloc_error:
+       yaffs_deinit_blocks(dev);
+       return YAFFS_FAIL;
+}
+
+
+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;
+       int i;
+
+       /* If the block is still healthy erase it and mark as clean.
+        * If the block has had a data failure, then retire it.
+        */
+
+       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 this is the block being garbage collected then stop gc'ing */
+       if (block_no == dev->gc_block)
+               dev->gc_block = 0;
+
+       /* If this block is currently the best candidate for gc
+        * then drop as a candidate */
+       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);
+               }
+       }
+
+       /* Verify erasure if needed */
+       if (erased_ok &&
+           ((yaffs_trace_mask & YAFFS_TRACE_ERASE) ||
+            !yaffs_skip_verification(dev))) {
+               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) {
+               /* We lost a block of free space */
+               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);
+               return;
+       }
+
+       /* Clean it up... */
+       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;      /* Clean, so no need to check */
+       bi->gc_prioritise = 0;
+       bi->has_summary = 0;
+
+       yaffs_clear_chunk_bits(dev, block_no);
+
+       yaffs_trace(YAFFS_TRACE_ERASE, "Erased block %d", block_no);
+}
+
+static inline int yaffs_gc_process_chunk(struct yaffs_dev *dev,
+                                       struct yaffs_block_info *bi,
+                                       int old_chunk, u8 *buffer)
+{
+       int new_chunk;
+       int mark_flash = 1;
+       struct yaffs_ext_tags tags;
+       struct yaffs_obj *object;
+       int matching_chunk;
+       int ret_val = YAFFS_OK;
+
+       memset(&tags, 0, sizeof(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)
+                       /* Defeat the test */
+                       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) {
+               /* Data chunk in a soft deleted file,
+                * throw it away.
+                * It's a soft deleted data chunk,
+                * No need to copy this, just forget
+                * about it and fix up the object.
+                */
+
+               /* Free chunks already includes
+                * softdeleted chunks, how ever this
+                * chunk is going to soon be really
+                * deleted which will increment free
+                * chunks. We have to decrement free
+                * chunks so this works out properly.
+                */
+               dev->n_free_chunks--;
+               bi->soft_del_pages--;
+
+               object->n_data_chunks--;
+               if (object->n_data_chunks <= 0) {
+                       /* remeber to clean up obj */
+                       dev->gc_cleanup_list[dev->n_clean_ups] = tags.obj_id;
+                       dev->n_clean_ups++;
+               }
+               mark_flash = 0;
+       } else if (object) {
+               /* It's either a data chunk in a live
+                * file or an ObjectHeader, so we're
+                * interested in it.
+                * NB Need to keep the ObjectHeaders of
+                * deleted files until the whole file
+                * has been deleted off
+                */
+               tags.serial_number++;
+               dev->n_gc_copies++;
+
+               if (tags.chunk_id == 0) {
+                       /* It is an object Id,
+                        * We need to nuke the
+                        * shrinkheader flags since its
+                        * work is done.
+                        * Also need to clean up
+                        * shadowing.
+                        */
+                       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;
+
+                       /* Update file size */
+                       if (object->variant_type == YAFFS_OBJECT_TYPE_FILE) {
+                               yaffs_oh_size_load(oh,
+                                   object->variant.file_variant.file_size);
+                               tags.extra_file_size =
+                                   object->variant.file_variant.file_size;
+                       }
+
+                       yaffs_verify_oh(object, oh, &tags, 1);
+                       new_chunk =
+                           yaffs_write_new_chunk(dev, (u8 *) oh, &tags, 1);
+               } else {
+                       new_chunk =
+                           yaffs_write_new_chunk(dev, buffer, &tags, 1);
+               }
+
+               if (new_chunk < 0) {
+                       ret_val = YAFFS_FAIL;
+               } else {
+
+                       /* Now fix up the Tnodes etc. */
+
+                       if (tags.chunk_id == 0) {
+                               /* It's a header */
+                               object->hdr_chunk = new_chunk;
+                               object->serial = tags.serial_number;
+                       } else {
+                               /* It's a data chunk */
+                               yaffs_put_chunk_in_file(object, tags.chunk_id,
+                                                       new_chunk, 0);
+                       }
+               }
+       }
+       if (ret_val == YAFFS_OK)
+               yaffs_chunk_del(dev, old_chunk, mark_flash, __LINE__);
+       return ret_val;
+}
+
+static int yaffs_gc_block(struct yaffs_dev *dev, int block, int whole_block)
+{
+       int old_chunk;
+       int ret_val = YAFFS_OK;
+       int i;
+       int is_checkpt_block;
+       int max_copies;
+       int chunks_before = yaffs_get_erased_chunks(dev);
+       int chunks_after;
+       struct yaffs_block_info *bi = yaffs_get_block_info(dev, block);
+
+       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);
+
+       /*yaffs_verify_free_chunks(dev); */
+
+       if (bi->block_state == YAFFS_BLOCK_STATE_FULL)
+               bi->block_state = YAFFS_BLOCK_STATE_COLLECTING;
+
+       bi->has_shrink_hdr = 0; /* clear the flag so that the block can erase */
+
+       dev->gc_disable = 1;
+
+       yaffs_summary_gc(dev, block);
+
+       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);
+
+               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 (/* init already done */ ;
+                    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)) {
+                               /* Page is in use and might need to be copied */
+                               max_copies--;
+                               ret_val = yaffs_gc_process_chunk(dev, bi,
+                                                       old_chunk, buffer);
+                       }
+               }
+               yaffs_release_temp_buffer(dev, buffer);
+       }
+
+       yaffs_verify_collected_blk(dev, bi, block);
+
+       if (bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
+               /*
+                * The gc did not complete. Set block state back to FULL
+                * because checkpointing does not restore gc.
+                */
+               bi->block_state = YAFFS_BLOCK_STATE_FULL;
+       } else {
+               /* The gc completed. */
+               /* Do any required cleanups */
+               for (i = 0; i < dev->n_clean_ups; i++) {
+                       /* Time to delete the file too */
+                       struct yaffs_obj *object =
+                           yaffs_find_by_number(dev, dev->gc_cleanup_list[i]);
+                       if (object) {
+                               yaffs_free_tnode(dev,
+                                         object->variant.file_variant.top);
+                               object->variant.file_variant.top = NULL;
+                               yaffs_trace(YAFFS_TRACE_GC,
+                                       "yaffs: About to finally delete object %d",
+                                       object->obj_id);
+                               yaffs_generic_obj_del(object);
+                               object->my_dev->n_deleted_files--;
+                       }
+
+               }
+               chunks_after = yaffs_get_erased_chunks(dev);
+               if (chunks_before >= chunks_after)
+                       yaffs_trace(YAFFS_TRACE_GC,
+                               "gc did not increase free chunks before %d after %d",
+                               chunks_before, chunks_after);
+               dev->gc_block = 0;
+               dev->gc_chunk = 0;
+               dev->n_clean_ups = 0;
+       }
+
+       dev->gc_disable = 0;
+
+       return ret_val;
+}
+
+/*
+ * find_gc_block() selects the dirtiest block (or close enough)
+ * for garbage collection.
+ */
+
+static unsigned yaffs_find_gc_block(struct yaffs_dev *dev,
+                                   int aggressive, int background)
+{
+       int i;
+       int iterations;
+       unsigned selected = 0;
+       int prioritised = 0;
+       int prioritised_exist = 0;
+       struct yaffs_block_info *bi;
+       int threshold;
+
+       /* First let's see if we need to grab a prioritised block */
+       if (dev->has_pending_prioritised_gc && !aggressive) {
+               dev->gc_dirtiest = 0;
+               bi = dev->block_info;
+               for (i = dev->internal_start_block;
+                    i <= dev->internal_end_block && !selected; i++) {
+
+                       if (bi->gc_prioritise) {
+                               prioritised_exist = 1;
+                               if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
+                                   yaffs_block_ok_for_gc(dev, bi)) {
+                                       selected = i;
+                                       prioritised = 1;
+                               }
+                       }
+                       bi++;
+               }
+
+               /*
+                * If there is a prioritised block and none was selected then
+                * this happened because there is at least one old dirty block
+                * gumming up the works. Let's gc the oldest dirty block.
+                */
+
+               if (prioritised_exist &&
+                   !selected && dev->oldest_dirty_block > 0)
+                       selected = dev->oldest_dirty_block;
+
+               if (!prioritised_exist) /* None found, so we can clear this */
+                       dev->has_pending_prioritised_gc = 0;
+       }
+
+       /* If we're doing aggressive GC then we are happy to take a less-dirty
+        * block, and search harder.
+        * else (leasurely gc), then we only bother to do this if the
+        * block has only a few pages in use.
+        */
+
+       if (!selected) {
+               int pages_used;
+               int n_blocks =
+                   dev->internal_end_block - dev->internal_start_block + 1;
+               if (aggressive) {
+                       threshold = dev->param.chunks_per_block;
+                       iterations = n_blocks;
+               } else {
+                       int max_threshold;
+
+                       if (background)
+                               max_threshold = dev->param.chunks_per_block / 2;
+                       else
+                               max_threshold = dev->param.chunks_per_block / 8;
+
+                       if (max_threshold < YAFFS_GC_PASSIVE_THRESHOLD)
+                               max_threshold = YAFFS_GC_PASSIVE_THRESHOLD;
+
+                       threshold = background ? (dev->gc_not_done + 2) * 2 : 0;
+                       if (threshold < YAFFS_GC_PASSIVE_THRESHOLD)
+                               threshold = YAFFS_GC_PASSIVE_THRESHOLD;
+                       if (threshold > max_threshold)
+                               threshold = max_threshold;
+
+                       iterations = n_blocks / 16 + 1;
+                       if (iterations > 100)
+                               iterations = 100;
+               }
+
+               for (i = 0;
+                    i < iterations &&
+                    (dev->gc_dirtiest < 1 ||
+                     dev->gc_pages_in_use > YAFFS_GC_GOOD_ENOUGH);
+                    i++) {
+                       dev->gc_block_finder++;
+                       if (dev->gc_block_finder < dev->internal_start_block ||
+                           dev->gc_block_finder > dev->internal_end_block)
+                               dev->gc_block_finder =
+                                   dev->internal_start_block;
+
+                       bi = yaffs_get_block_info(dev, dev->gc_block_finder);
+
+                       pages_used = bi->pages_in_use - bi->soft_del_pages;
+
+                       if (bi->block_state == YAFFS_BLOCK_STATE_FULL &&
+                           pages_used < dev->param.chunks_per_block &&
+                           (dev->gc_dirtiest < 1 ||
+                            pages_used < dev->gc_pages_in_use) &&
+                           yaffs_block_ok_for_gc(dev, bi)) {
+                               dev->gc_dirtiest = dev->gc_block_finder;
+                               dev->gc_pages_in_use = pages_used;
+                       }
+               }
+
+               if (dev->gc_dirtiest > 0 && dev->gc_pages_in_use <= threshold)
+                       selected = dev->gc_dirtiest;
+       }
+
+       /*
+        * If nothing has been selected for a while, try the oldest dirty
+        * because that's gumming up the works.
+        */
+
+       if (!selected && dev->param.is_yaffs2 &&
+           dev->gc_not_done >= (background ? 10 : 20)) {
+               yaffs2_find_oldest_dirty_seq(dev);
+               if (dev->oldest_dirty_block > 0) {
+                       selected = dev->oldest_dirty_block;
+                       dev->gc_dirtiest = selected;
+                       dev->oldest_dirty_gc_count++;
+                       bi = yaffs_get_block_info(dev, selected);
+                       dev->gc_pages_in_use =
+                           bi->pages_in_use - bi->soft_del_pages;
+               } else {
+                       dev->gc_not_done = 0;
+               }
+       }
+
+       if (selected) {
+               yaffs_trace(YAFFS_TRACE_GC,
+                       "GC Selected block %d with %d free, prioritised:%d",
+                       selected,
+                       dev->param.chunks_per_block - dev->gc_pages_in_use,
+                       prioritised);
+
+               dev->n_gc_blocks++;
+               if (background)
+                       dev->bg_gcs++;
+
+               dev->gc_dirtiest = 0;
+               dev->gc_pages_in_use = 0;
+               dev->gc_not_done = 0;
+               if (dev->refresh_skip > 0)
+                       dev->refresh_skip--;
+       } else {
+               dev->gc_not_done++;
+               yaffs_trace(YAFFS_TRACE_GC,
+                       "GC none: finder %d skip %d threshold %d dirtiest %d using %d oldest %d%s",
+                       dev->gc_block_finder, dev->gc_not_done, threshold,
+                       dev->gc_dirtiest, dev->gc_pages_in_use,
+                       dev->oldest_dirty_block, background ? " bg" : "");
+       }
+
+       return selected;
+}
+
+/* New garbage collector
+ * If we're very low on erased blocks then we do aggressive garbage collection
+ * otherwise we do "leasurely" garbage collection.
+ * Aggressive gc looks further (whole array) and will accept less dirty blocks.
+ * Passive gc only inspects smaller areas and only accepts more dirty blocks.
+ *
+ * The idea is to help clear out space in a more spread-out manner.
+ * Dunno if it really does anything useful.
+ */
+static int yaffs_check_gc(struct yaffs_dev *dev, int background)
+{
+       int aggressive = 0;
+       int gc_ok = YAFFS_OK;
+       int max_tries = 0;
+       int min_erased;
+       int erased_chunks;
+       int checkpt_block_adjust;
+
+       if (dev->param.gc_control && (dev->param.gc_control(dev) & 1) == 0)
+               return YAFFS_OK;
+
+       if (dev->gc_disable)
+               /* Bail out so we don't get recursive gc */
+               return YAFFS_OK;
+
+       /* This loop should pass the first time.
+        * Only loops here if the collection does not increase space.
+        */
+
+       do {
+               max_tries++;
+
+               checkpt_block_adjust = yaffs_calc_checkpt_blocks_required(dev);
+
+               min_erased =
+                   dev->param.n_reserved_blocks + checkpt_block_adjust + 1;
+               erased_chunks =
+                   dev->n_erased_blocks * dev->param.chunks_per_block;
+
+               /* If we need a block soon then do aggressive gc. */
+               if (dev->n_erased_blocks < min_erased)
+                       aggressive = 1;
+               else {
+                       if (!background
+                           && erased_chunks > (dev->n_free_chunks / 4))
+                               break;
+
+                       if (dev->gc_skip > 20)
+                               dev->gc_skip = 20;
+                       if (erased_chunks < dev->n_free_chunks / 2 ||
+                           dev->gc_skip < 1 || background)
+                               aggressive = 0;
+                       else {
+                               dev->gc_skip--;
+                               break;
+                       }
+               }
+
+               dev->gc_skip = 5;
+
+               /* If we don't already have a block being gc'd then see if we
+                * should start another */
+
+               if (dev->gc_block < 1 && !aggressive) {
+                       dev->gc_block = yaffs2_find_refresh_block(dev);
+                       dev->gc_chunk = 0;
+                       dev->n_clean_ups = 0;
+               }
+               if (dev->gc_block < 1) {
+                       dev->gc_block =
+                           yaffs_find_gc_block(dev, aggressive, background);
+                       dev->gc_chunk = 0;
+                       dev->n_clean_ups = 0;
+               }
+
+               if (dev->gc_block > 0) {
+                       dev->all_gcs++;
+                       if (!aggressive)
+                               dev->passive_gc_count++;
+
+                       yaffs_trace(YAFFS_TRACE_GC,
+                               "yaffs: GC n_erased_blocks %d aggressive %d",
+                               dev->n_erased_blocks, aggressive);
+
+                       gc_ok = yaffs_gc_block(dev, dev->gc_block, aggressive);
+               }
+
+               if (dev->n_erased_blocks < (dev->param.n_reserved_blocks) &&
+                   dev->gc_block > 0) {
+                       yaffs_trace(YAFFS_TRACE_GC,
+                               "yaffs: GC !!!no reclaim!!! n_erased_blocks %d after try %d block %d",
+                               dev->n_erased_blocks, max_tries,
+                               dev->gc_block);
+               }
+       } while ((dev->n_erased_blocks < dev->param.n_reserved_blocks) &&
+                (dev->gc_block > 0) && (max_tries < 2));
+
+       return aggressive ? gc_ok : YAFFS_OK;
+}
+
+/*
+ * yaffs_bg_gc()
+ * Garbage collects. Intended to be called from a background thread.
+ * Returns non-zero if at least half the free chunks are erased.
+ */
+int yaffs_bg_gc(struct yaffs_dev *dev, unsigned urgency)
+{
+       int erased_chunks = dev->n_erased_blocks * dev->param.chunks_per_block;
+
+       yaffs_trace(YAFFS_TRACE_BACKGROUND, "Background gc %u", urgency);
+
+       yaffs_check_gc(dev, 1);
+       return erased_chunks > dev->n_free_chunks / 2;
+}
+
+/*-------------------- Data file manipulation -----------------*/
+
+static int yaffs_rd_data_obj(struct yaffs_obj *in, int inode_chunk, u8 * buffer)
+{
+       int nand_chunk = yaffs_find_chunk_in_file(in, inode_chunk, NULL);
+
+       if (nand_chunk >= 0)
+               return yaffs_rd_chunk_tags_nand(in->my_dev, nand_chunk,
+                                               buffer, NULL);
+       else {
+               yaffs_trace(YAFFS_TRACE_NANDACCESS,
+                       "Chunk %d not found zero instead",
+                       nand_chunk);
+               /* get sane (zero) data if you read a hole */
+               memset(buffer, 0, in->my_dev->data_bytes_per_chunk);
+               return 0;
+       }
+
+}
+
+void yaffs_chunk_del(struct yaffs_dev *dev, int chunk_id, int mark_flash,
+                    int lyn)
+{
+       int block;
+       int page;
+       struct yaffs_ext_tags tags;
+       struct yaffs_block_info *bi;
+
+       if (chunk_id <= 0)
+               return;
+
+       dev->n_deletions++;
+       block = chunk_id / dev->param.chunks_per_block;
+       page = chunk_id % dev->param.chunks_per_block;
+
+       if (!yaffs_check_chunk_bit(dev, block, page))
+               yaffs_trace(YAFFS_TRACE_VERIFY,
+                       "Deleting invalid chunk %d", chunk_id);
+
+       bi = yaffs_get_block_info(dev, block);
+
+       yaffs2_update_oldest_dirty_seq(dev, block, bi);
+
+       yaffs_trace(YAFFS_TRACE_DELETION,
+               "line %d delete of chunk %d",
+               lyn, chunk_id);
+
+       if (!dev->param.is_yaffs2 && mark_flash &&
+           bi->block_state != YAFFS_BLOCK_STATE_COLLECTING) {
+
+               memset(&tags, 0, sizeof(tags));
+               tags.is_deleted = 1;
+               yaffs_wr_chunk_tags_nand(dev, chunk_id, NULL, &tags);
+               yaffs_handle_chunk_update(dev, chunk_id, &tags);
+       } else {
+               dev->n_unmarked_deletions++;
+       }
+
+       /* Pull out of the management area.
+        * If the whole block became dirty, this will kick off an erasure.
+        */
+       if (bi->block_state == YAFFS_BLOCK_STATE_ALLOCATING ||
+           bi->block_state == YAFFS_BLOCK_STATE_FULL ||
+           bi->block_state == YAFFS_BLOCK_STATE_NEEDS_SCAN ||
+           bi->block_state == YAFFS_BLOCK_STATE_COLLECTING) {
+               dev->n_free_chunks++;
+               yaffs_clear_chunk_bit(dev, block, page);
+               bi->pages_in_use--;
+
+               if (bi->pages_in_use == 0 &&
+                   !bi->has_shrink_hdr &&
+                   bi->block_state != YAFFS_BLOCK_STATE_ALLOCATING &&
+                   bi->block_state != YAFFS_BLOCK_STATE_NEEDS_SCAN) {
+                       yaffs_block_became_dirty(dev, block);
+               }
+       }
+}
+
+static int yaffs_wr_data_obj(struct yaffs_obj *in, int inode_chunk,
+                            const u8 *buffer, int n_bytes, int use_reserve)
+{
+       /* Find old chunk Need to do this to get serial number
+        * Write new one and patch into tree.
+        * Invalidate old tags.
+        */
+
+       int prev_chunk_id;
+       struct yaffs_ext_tags prev_tags;
+       int new_chunk_id;
+       struct yaffs_ext_tags new_tags;
+       struct yaffs_dev *dev = in->my_dev;
+
+       yaffs_check_gc(dev, 0);
+
+       /* Get the previous chunk at this location in the file if it exists.
+        * If it does not exist then put a zero into the tree. This creates
+        * the tnode now, rather than later when it is harder to clean up.
+        */
+       prev_chunk_id = yaffs_find_chunk_in_file(in, inode_chunk, &prev_tags);
+       if (prev_chunk_id < 1 &&
+           !yaffs_put_chunk_in_file(in, inode_chunk, 0, 0))
+               return 0;
+
+       /* Set up new tags */
+       memset(&new_tags, 0, sizeof(new_tags));
+
+       new_tags.chunk_id = inode_chunk;
+       new_tags.obj_id = in->obj_id;
+       new_tags.serial_number =
+           (prev_chunk_id > 0) ? prev_tags.serial_number + 1 : 1;
+       new_tags.n_bytes = n_bytes;
+
+       if (n_bytes < 1 || n_bytes > dev->param.total_bytes_per_chunk) {
+               yaffs_trace(YAFFS_TRACE_ERROR,
+                 "Writing %d bytes to chunk!!!!!!!!!",
+                  n_bytes);
+               BUG();
+       }
+
+       new_chunk_id =
+           yaffs_write_new_chunk(dev, buffer, &new_tags, use_reserve);
+
+       if (new_chunk_id > 0) {
+               yaffs_put_chunk_in_file(in, inode_chunk, new_chunk_id, 0);
+
+               if (prev_chunk_id > 0)
+                       yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);
+
+               yaffs_verify_file_sane(in);
+       }
+       return new_chunk_id;
+
+}
+
+
+
+static int yaffs_do_xattrib_mod(struct yaffs_obj *obj, int set,
+                               const YCHAR *name, const void *value, int size,
+                               int flags)
+{
+       struct yaffs_xattr_mod xmod;
+       int result;
+
+       xmod.set = set;
+       xmod.name = name;
+       xmod.data = value;
+       xmod.size = size;
+       xmod.flags = flags;
+       xmod.result = -ENOSPC;
+
+       result = yaffs_update_oh(obj, NULL, 0, 0, 0, &xmod);
+
+       if (result > 0)
+               return xmod.result;
+       else
+               return -ENOSPC;
+}
+
+static int yaffs_apply_xattrib_mod(struct yaffs_obj *obj, char *buffer,
+                                  struct yaffs_xattr_mod *xmod)
+{
+       int retval = 0;
+       int x_offs = sizeof(struct yaffs_obj_hdr);
+       struct yaffs_dev *dev = obj->my_dev;
+       int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
+       char *x_buffer = buffer + x_offs;
+
+       if (xmod->set)
+               retval =
+                   nval_set(x_buffer, x_size, xmod->name, xmod->data,
+                            xmod->size, xmod->flags);
+       else
+               retval = nval_del(x_buffer, x_size, xmod->name);
+
+       obj->has_xattr = nval_hasvalues(x_buffer, x_size);
+       obj->xattr_known = 1;
+       xmod->result = retval;
+
+       return retval;
+}
+
+static int yaffs_do_xattrib_fetch(struct yaffs_obj *obj, const YCHAR *name,
+                                 void *value, int size)
+{
+       char *buffer = NULL;
+       int result;
+       struct yaffs_ext_tags tags;
+       struct yaffs_dev *dev = obj->my_dev;
+       int x_offs = sizeof(struct yaffs_obj_hdr);
+       int x_size = dev->data_bytes_per_chunk - sizeof(struct yaffs_obj_hdr);
+       char *x_buffer;
+       int retval = 0;
+
+       if (obj->hdr_chunk < 1)
+               return -ENODATA;
+
+       /* If we know that the object has no xattribs then don't do all the
+        * reading and parsing.
+        */
+       if (obj->xattr_known && !obj->has_xattr) {
+               if (name)
+                       return -ENODATA;
+               else
+                       return 0;
+       }
+
+       buffer = (char *)yaffs_get_temp_buffer(dev);
+       if (!buffer)
+               return -ENOMEM;
+
+       result =
+           yaffs_rd_chunk_tags_nand(dev, obj->hdr_chunk, (u8 *) buffer, &tags);
+
+       if (result != YAFFS_OK)
+               retval = -ENOENT;
+       else {
+               x_buffer = buffer + x_offs;
+
+               if (!obj->xattr_known) {
+                       obj->has_xattr = nval_hasvalues(x_buffer, x_size);
+                       obj->xattr_known = 1;
+               }
+
+               if (name)
+                       retval = nval_get(x_buffer, x_size, name, value, size);
+               else
+                       retval = nval_list(x_buffer, x_size, value, size);
+       }
+       yaffs_release_temp_buffer(dev, (u8 *) buffer);
+       return retval;
+}
+
+int yaffs_set_xattrib(struct yaffs_obj *obj, const YCHAR * name,
+                     const void *value, int size, int flags)
+{
+       return yaffs_do_xattrib_mod(obj, 1, name, value, size, flags);
+}
+
+int yaffs_remove_xattrib(struct yaffs_obj *obj, const YCHAR * name)
+{
+       return yaffs_do_xattrib_mod(obj, 0, name, NULL, 0, 0);
+}
+
+int yaffs_get_xattrib(struct yaffs_obj *obj, const YCHAR * name, void *value,
+                     int size)
+{
+       return yaffs_do_xattrib_fetch(obj, name, value, size);
+}
+
+int yaffs_list_xattrib(struct yaffs_obj *obj, char *buffer, int size)
+{
+       return yaffs_do_xattrib_fetch(obj, NULL, buffer, size);
+}
+
+static void yaffs_check_obj_details_loaded(struct yaffs_obj *in)
+{
+       u8 *buf;
+       struct yaffs_obj_hdr *oh;
+       struct yaffs_dev *dev;
+       struct yaffs_ext_tags tags;
+
+       if (!in || !in->lazy_loaded || in->hdr_chunk < 1)
+               return;
+
+       dev = in->my_dev;
+       in->lazy_loaded = 0;
+       buf = yaffs_get_temp_buffer(dev);
+
+       yaffs_rd_chunk_tags_nand(dev, in->hdr_chunk, buf, &tags);
+       oh = (struct yaffs_obj_hdr *)buf;
+
+       in->yst_mode = oh->yst_mode;
+       yaffs_load_attribs(in, oh);
+       yaffs_set_obj_name_from_oh(in, oh);
+
+       if (in->variant_type == YAFFS_OBJECT_TYPE_SYMLINK) {
+               in->variant.symlink_variant.alias =
+                   yaffs_clone_str(oh->alias);
+       }
+       yaffs_release_temp_buffer(dev, buf);
+}
+
+static void yaffs_load_name_from_oh(struct yaffs_dev *dev, YCHAR *name,
+                                   const YCHAR *oh_name, int buff_size)
+{
+#ifdef CONFIG_YAFFS_AUTO_UNICODE
+       if (dev->param.auto_unicode) {
+               if (*oh_name) {
+                       /* It is an ASCII name, do an ASCII to
+                        * unicode conversion */
+                       const char *ascii_oh_name = (const char *)oh_name;
+                       int n = buff_size - 1;
+                       while (n > 0 && *ascii_oh_name) {
+                               *name = *ascii_oh_name;
+                               name++;
+                               ascii_oh_name++;
+                               n--;
+                       }
+               } else {
+                       yaffs_strncpy(name, oh_name + 1, buff_size - 1);
+               }
+       } else {
+#else
+       dev = dev;
+       {
+#endif
+               yaffs_strncpy(name, oh_name, buff_size - 1);
+       }
+}
+
+static void yaffs_load_oh_from_name(struct yaffs_dev *dev, YCHAR *oh_name,
+                                   const YCHAR *name)
+{
+#ifdef CONFIG_YAFFS_AUTO_UNICODE
+
+       int is_ascii;
+       YCHAR *w;
+
+       if (dev->param.auto_unicode) {
+
+               is_ascii = 1;
+               w = name;
+
+               /* Figure out if the name will fit in ascii character set */
+               while (is_ascii && *w) {
+                       if ((*w) & 0xff00)
+                               is_ascii = 0;
+                       w++;
+               }
+
+               if (is_ascii) {
+                       /* It is an ASCII name, so convert unicode to ascii */
+                       char *ascii_oh_name = (char *)oh_name;
+                       int n = YAFFS_MAX_NAME_LENGTH - 1;
+                       while (n > 0 && *name) {
+                               *ascii_oh_name = *name;
+                               name++;
+                               ascii_oh_name++;
+                               n--;
+                       }
+               } else {
+                       /* Unicode name, so save starting at the second YCHAR */
+                       *oh_name = 0;
+                       yaffs_strncpy(oh_name + 1, name, YAFFS_MAX_NAME_LENGTH - 2);
+               }
+       } else {
+#else
+       dev = dev;
+       {
+#endif
+               yaffs_strncpy(oh_name, name, YAFFS_MAX_NAME_LENGTH - 1);
+       }
+}
+
+/* UpdateObjectHeader updates the header on NAND for an object.
+ * If name is not NULL, then that new name is used.
+ */
+int yaffs_update_oh(struct yaffs_obj *in, const YCHAR *name, int force,
+                   int is_shrink, int shadows, struct yaffs_xattr_mod *xmod)
+{
+
+       struct yaffs_block_info *bi;
+       struct yaffs_dev *dev = in->my_dev;
+       int prev_chunk_id;
+       int ret_val = 0;
+       int new_chunk_id;
+       struct yaffs_ext_tags new_tags;
+       struct yaffs_ext_tags old_tags;
+       const YCHAR *alias = NULL;
+       u8 *buffer = NULL;
+       YCHAR old_name[YAFFS_MAX_NAME_LENGTH + 1];
+       struct yaffs_obj_hdr *oh = NULL;
+       loff_t file_size = 0;
+
+       yaffs_strcpy(old_name, _Y("silly old name"));
+
+       if (in->fake && in != dev->root_dir && !force && !xmod)
+               return ret_val;
+
+       yaffs_check_gc(dev, 0);
+       yaffs_check_obj_details_loaded(in);
+
+       buffer = yaffs_get_temp_buffer(in->my_dev);
+       oh = (struct yaffs_obj_hdr *)buffer;
+
+       prev_chunk_id = in->hdr_chunk;
+
+       if (prev_chunk_id > 0) {
+               yaffs_rd_chunk_tags_nand(dev, prev_chunk_id,
+                                         buffer, &old_tags);
+
+               yaffs_verify_oh(in, oh, &old_tags, 0);
+               memcpy(old_name, oh->name, sizeof(oh->name));
+               memset(buffer, 0xff, sizeof(struct yaffs_obj_hdr));
+       } else {
+               memset(buffer, 0xff, dev->data_bytes_per_chunk);
+       }
+
+       oh->type = in->variant_type;
+       oh->yst_mode = in->yst_mode;
+       oh->shadows_obj = oh->inband_shadowed_obj_id = shadows;
+
+       yaffs_load_attribs_oh(oh, in);
+
+       if (in->parent)
+               oh->parent_obj_id = in->parent->obj_id;
+       else
+               oh->parent_obj_id = 0;
+
+       if (name && *name) {
+               memset(oh->name, 0, sizeof(oh->name));
+               yaffs_load_oh_from_name(dev, oh->name, name);
+       } else if (prev_chunk_id > 0) {
+               memcpy(oh->name, old_name, sizeof(oh->name));
+       } else {
+               memset(oh->name, 0, sizeof(oh->name));
+       }
+
+       oh->is_shrink = is_shrink;
+
+       switch (in->variant_type) {
+       case YAFFS_OBJECT_TYPE_UNKNOWN:
+               /* Should not happen */
+               break;
+       case YAFFS_OBJECT_TYPE_FILE:
+               if (oh->parent_obj_id != YAFFS_OBJECTID_DELETED &&
+                   oh->parent_obj_id != YAFFS_OBJECTID_UNLINKED)
+                       file_size = in->variant.file_variant.file_size;
+               yaffs_oh_size_load(oh, file_size);
+               break;
+       case YAFFS_OBJECT_TYPE_HARDLINK:
+               oh->equiv_id = in->variant.hardlink_variant.equiv_id;
+               break;
+       case YAFFS_OBJECT_TYPE_SPECIAL:
+               /* Do nothing */
+               break;
+       case YAFFS_OBJECT_TYPE_DIRECTORY:
+               /* Do nothing */
+               break;
+       case YAFFS_OBJECT_TYPE_SYMLINK:
+               alias = in->variant.symlink_variant.alias;
+               if (!alias)
+                       alias = _Y("no alias");
+               yaffs_strncpy(oh->alias, alias, YAFFS_MAX_ALIAS_LENGTH);
+               oh->alias[YAFFS_MAX_ALIAS_LENGTH] = 0;
+               break;
+       }
+
+       /* process any xattrib modifications */
+       if (xmod)
+               yaffs_apply_xattrib_mod(in, (char *)buffer, xmod);
+
+       /* Tags */
+       memset(&new_tags, 0, sizeof(new_tags));
+       in->serial++;
+       new_tags.chunk_id = 0;
+       new_tags.obj_id = in->obj_id;
+       new_tags.serial_number = in->serial;
+
+       /* Add extra info for file header */
+       new_tags.extra_available = 1;
+       new_tags.extra_parent_id = oh->parent_obj_id;
+       new_tags.extra_file_size = file_size;
+       new_tags.extra_is_shrink = oh->is_shrink;
+       new_tags.extra_equiv_id = oh->equiv_id;
+       new_tags.extra_shadows = (oh->shadows_obj > 0) ? 1 : 0;
+       new_tags.extra_obj_type = in->variant_type;
+       yaffs_verify_oh(in, oh, &new_tags, 1);
+
+       /* Create new chunk in NAND */
+       new_chunk_id =
+           yaffs_write_new_chunk(dev, buffer, &new_tags,
+                                 (prev_chunk_id > 0) ? 1 : 0);
+
+       if (buffer)
+               yaffs_release_temp_buffer(dev, buffer);
+
+       if (new_chunk_id < 0)
+               return new_chunk_id;
+
+       in->hdr_chunk = new_chunk_id;
+
+       if (prev_chunk_id > 0)
+               yaffs_chunk_del(dev, prev_chunk_id, 1, __LINE__);
+
+       if (!yaffs_obj_cache_dirty(in))
+               in->dirty = 0;
+
+       /* If this was a shrink, then mark the block
+        * that the chunk lives on */
+       if (is_shrink) {
+               bi = yaffs_get_block_info(in->my_dev,
+                                         new_chunk_id /
+                                         in->my_dev->param.chunks_per_block);
+               bi->has_shrink_hdr = 1;
+       }
+
+
+       return new_chunk_id;
+}
+
+/*--------------------- File read/write ------------------------
+ * Read and write have very similar structures.
+ * In general the read/write has three parts to it
+ * An incomplete chunk to start with (if the read/write is not chunk-aligned)
+ * Some complete chunks
+ * An incomplete chunk to end off with
+ *
+ * Curve-balls: the first chunk might also be the last chunk.
+ */
+
+int yaffs_file_rd(struct yaffs_obj *in, u8 * buffer, loff_t offset, int n_bytes)
+{
+       int chunk;
+       u32 start;
+       int n_copy;
+       int n = n_bytes;
+       int n_done = 0;
+       struct yaffs_cache *cache;
+       struct yaffs_dev *dev;
+
+       dev = in->my_dev;
+
+       while (n > 0) {
+               yaffs_addr_to_chunk(dev, offset, &chunk, &start);
+               chunk++;
+
+               /* OK now check for the curveball where the start and end are in
+                * the same chunk.
+                */
+               if ((start + n) < dev->data_bytes_per_chunk)
+                       n_copy = n;
+               else
+                       n_copy = dev->data_bytes_per_chunk - start;
+
+               cache = yaffs_find_chunk_cache(in, chunk);
+
+               /* If the chunk is already in the cache or it is less than
+                * a whole chunk or we're using inband tags then use the cache
+                * (if there is caching) else bypass the cache.
+                */
+               if (cache || n_copy != dev->data_bytes_per_chunk ||
+                   dev->param.inband_tags) {
+                       if (dev->param.n_caches > 0) {
+
+                               /* If we can't find the data in the cache,
+                                * then load it up. */
+
+                               if (!cache) {
+                                       cache =
+                                           yaffs_grab_chunk_cache(in->my_dev);
+                                       cache->object = in;
+                                       cache->chunk_id = chunk;
+                                       cache->dirty = 0;
+                                       cache->locked = 0;
+                                       yaffs_rd_data_obj(in, chunk,
+                                                         cache->data);
+                                       cache->n_bytes = 0;
+                               }
+
+                               yaffs_use_cache(dev, cache, 0);
+
+                               cache->locked = 1;
+
+                               memcpy(buffer, &cache->data[start], n_copy);
+
+                               cache->locked = 0;
+                       } else {
+                               /* Read into the local buffer then copy.. */
+
+                               u8 *local_buffer =
+                                   yaffs_get_temp_buffer(dev);
+                               yaffs_rd_data_obj(in, chunk, local_buffer);
+
+                               memcpy(buffer, &local_buffer[start], n_copy);
+
+                               yaffs_release_temp_buffer(dev, local_buffer);
+                       }
+               } else {
+                       /* A full chunk. Read directly into the buffer. */
+                       yaffs_rd_data_obj(in, chunk, buffer);
+               }
+               n -= n_copy;
+               offset += n_copy;
+               buffer += n_copy;
+               n_done += n_copy;
+       }
+       return n_done;
+}
+
+int yaffs_do_file_wr(struct yaffs_obj *in, const u8 *buffer, loff_t offset,
+                    int n_bytes, int write_through)
+{
+
+       int chunk;
+       u32 start;
+       int n_copy;
+       int n = n_bytes;
+       int n_done = 0;
+       int n_writeback;
+       loff_t start_write = offset;
+       int chunk_written = 0;
+       u32 n_bytes_read;
+       loff_t chunk_start;
+       struct yaffs_dev *dev;
+
+       dev = in->my_dev;
+
+       while (n > 0 && chunk_written >= 0) {
+               yaffs_addr_to_chunk(dev, offset, &chunk, &start);
+
+               if (((loff_t)chunk) *
+                   dev->data_bytes_per_chunk + start != offset ||
+                   start >= dev->data_bytes_per_chunk) {
+                       yaffs_trace(YAFFS_TRACE_ERROR,
+                               "AddrToChunk of offset %lld gives chunk %d start %d",
+                               offset, chunk, start);
+               }
+               chunk++;        /* File pos to chunk in file offset */
+
+               /* OK now check for the curveball where the start and end are in
+                * the same chunk.
+                */
+
+               if ((start + n) < dev->data_bytes_per_chunk) {
+                       n_copy = n;
+
+                       /* Now calculate how many bytes to write back....
+                        * If we're overwriting and not writing to then end of
+                        * file then we need to write back as much as was there
+                        * before.
+                        */
+
+                       chunk_start = (((loff_t)(chunk - 1)) *
+                                       dev->data_bytes_per_chunk);
+
+                       if (chunk_start > in->variant.file_variant.file_size)
+                               n_bytes_read = 0;       /* Past end of file */
+                       else
+                               n_bytes_read =
+                                   in->variant.file_variant.file_size -
+                                   chunk_start;
+
+                       if (n_bytes_read > dev->data_bytes_per_chunk)
+                               n_bytes_read = dev->data_bytes_per_chunk;
+
+                       n_writeback =
+                           (n_bytes_read >
+                            (start + n)) ? n_bytes_read : (start + n);
+
+                       if (n_writeback < 0 ||
+                           n_writeback > dev->data_bytes_per_chunk)
+                               BUG();
+
+               } else {
+                       n_copy = dev->data_bytes_per_chunk - start;
+                       n_writeback = dev->data_bytes_per_chunk;
+               }
+
+               if (n_copy != dev->data_bytes_per_chunk ||
+                   dev->param.inband_tags) {
+                       /* An incomplete start or end chunk (or maybe both
+                        * start and end chunk), or we're using inband tags,
+                        * so we want to use the cache buffers.
+                        */
+                       if (dev->param.n_caches > 0) {
+                               struct yaffs_cache *cache;
+
+                               /* If we can't find the data in the cache, then
+                                * load the cache */
+                               cache = yaffs_find_chunk_cache(in, chunk);
+
+                               if (!cache &&
+                                   yaffs_check_alloc_available(dev, 1)) {
+                                       cache = yaffs_grab_chunk_cache(dev);
+                                       cache->object = in;
+                                       cache->chunk_id = chunk;
+                                       cache->dirty = 0;
+                                       cache->locked = 0;
+                                       yaffs_rd_data_obj(in, chunk,
+                                                         cache->data);
+                               } else if (cache &&
+                                          !cache->dirty &&
+                                          !yaffs_check_alloc_available(dev,
+                                                                       1)) {
+                                       /* Drop the cache if it was a read cache
+                                        * item and no space check has been made
+                                        * for it.
+                                        */
+                                       cache = NULL;
+                               }
+
+                               if (cache) {
+                                       yaffs_use_cache(dev, cache, 1);
+                                       cache->locked = 1;
+
+                                       memcpy(&cache->data[start], buffer,
+                                              n_copy);
+
+                                       cache->locked = 0;
+                                       cache->n_bytes = n_writeback;
+
+                                       if (write_through) {
+                                               chunk_written =
+                                                   yaffs_wr_data_obj
+                                                   (cache->object,
+                                                    cache->chunk_id,
+                                                    cache->data,
+                                                    cache->n_bytes, 1);
+                                               cache->dirty = 0;
+                                       }
+                               } else {
+                                       chunk_written = -1;     /* fail write */
+                               }
+                       } else {
+                               /* An incomplete start or end chunk (or maybe
+                                * both start and end chunk). Read into the
+                                * local buffer then copy over and write back.
+                                */
+
+                               u8 *local_buffer = yaffs_get_temp_buffer(dev);
+
+                               yaffs_rd_data_obj(in, chunk, local_buffer);
+                               memcpy(&local_buffer[start], buffer, n_copy);
+
+                               chunk_written =
+                                   yaffs_wr_data_obj(in, chunk,
+                                                     local_buffer,
+                                                     n_writeback, 0);
+
+                               yaffs_release_temp_buffer(dev, local_buffer);
+                       }
+               } else {
+                       /* A full chunk. Write directly from the buffer. */
+
+                       chunk_written =
+                           yaffs_wr_data_obj(in, chunk, buffer,
+                                             dev->data_bytes_per_chunk, 0);
+
+                       /* Since we've overwritten the cached data,
+                        * we better invalidate it. */
+                       yaffs_invalidate_chunk_cache(in, chunk);
+               }
+
+               if (chunk_written >= 0) {
+                       n -= n_copy;
+                       offset += n_copy;
+                       buffer += n_copy;
+                       n_done += n_copy;
+               }
+       }
+
+       /* Update file object */
+
+       if ((start_write + n_done) > in->variant.file_variant.file_size)
+               in->variant.file_variant.file_size = (start_write + n_done);
+
+       in->dirty = 1;
+       return n_done;
+}
+
+int yaffs_wr_file(struct yaffs_obj *in, const u8 *buffer, loff_t offset,
+                 int n_bytes, int write_through)
+{
+       yaffs2_handle_hole(in, offset);
+       return yaffs_do_file_wr(in, buffer, offset, n_bytes, write_through);
+}
+
+/* ---------------------- File resizing stuff ------------------ */
+
+static void yaffs_prune_chunks(struct yaffs_obj *in, loff_t new_size)
+{
+
+       struct yaffs_dev *dev = in->my_dev;
+       loff_t old_size = in->variant.file_variant.file_size;
+       int i;
+       int chunk_id;
+       u32 dummy;
+       int last_del;
+       int start_del;
+
+       if (old_size > 0)
+               yaffs_addr_to_chunk(dev, old_size - 1, &last_del, &dummy);
+       else
+               last_del = 0;
+
+       yaffs_addr_to_chunk(dev, new_size + dev->data_bytes_per_chunk - 1,
+                               &start_del, &dummy);
+       last_del++;
+       start_del++;
+
+       /* Delete backwards so that we don't end up with holes if
+        * power is lost part-way through the operation.
+        */
+       for (i = last_del; i >= start_del; i--) {
+               /* NB this could be optimised somewhat,
+                * eg. could retrieve the tags and write them without
+                * using yaffs_chunk_del
+                */
+
+               chunk_id = yaffs_find_del_file_chunk(in, i, NULL);
+
+               if (chunk_id < 1)
+                       continue;
+
+               if (chunk_id <
+                   (dev->internal_start_block * dev->param.chunks_per_block) ||
+                   chunk_id >=
+                   ((dev->internal_end_block + 1) *
+                     dev->param.chunks_per_block)) {
+                       yaffs_trace(YAFFS_TRACE_ALWAYS,
+                               "Found daft chunk_id %d for %d",
+                               chunk_id, i);
+               } else {
+                       in->n_data_chunks--;
+                       yaffs_chunk_del(dev, chunk_id, 1, __LINE__);
+               }
+       }
+}
+
+void yaffs_resize_file_down(struct yaffs_obj *obj, loff_t new_size)
+{
+       int new_full;
+       u32 new_partial;
+       struct yaffs_dev *dev = obj->my_dev;
+
+       yaffs_addr_to_chunk(dev, new_size, &new_full, &new_partial);
+
+       yaffs_prune_chunks(obj, new_size);
+
+       if (new_partial != 0) {
+               int last_chunk = 1 + new_full;
+               u8 *local_buffer = yaffs_get_temp_buffer(dev);
+
+               /* Rewrite the last chunk with its new size and zero pad */
+               yaffs_rd_data_obj(obj, last_chunk, local_buffer);
+               memset(local_buffer + new_partial, 0,
+                      dev->data_bytes_per_chunk - new_partial);
+
+               yaffs_wr_data_obj(obj, last_chunk, local_buffer,
+                                 new_partial, 1);
+
+               yaffs_release_temp_buffer(dev, local_buffer);
+       }
+
+       obj->variant.file_variant.file_size = new_size;
+
+       yaffs_prune_tree(dev, &obj->variant.file_variant);
+}
+
+int yaffs_resize_file(struct yaffs_obj *in, loff_t new_size)
+{
+       struct yaffs_dev *dev = in->my_dev;
+       loff_t old_size = in->variant.file_variant.file_size;
+
+       yaffs_flush_file_cache(in);
+       yaffs_invalidate_whole_cache(in);
+
+       yaffs_check_gc(dev, 0);
+
+       if (in->variant_type != YAFFS_OBJECT_TYPE_FILE)
+               return YAFFS_FAIL;
+
+       if (new_size == old_size)
+               return YAFFS_OK;
+
+       if (new_size > old_size) {
+               yaffs2_handle_hole(in, new_size);
+               in->variant.file_variant.file_size = new_size;
+       } else {
+               /* new_size < old_size */
+               yaffs_resize_file_down(in, new_size);
+       }
+
+       /* Write a new object header to reflect the resize.
+        * show we've shrunk the file, if need be
+        * Do this only if the file is not in the deleted directories
+        * and is not shadowed.
+        */
+       if (in->parent &&
+           !in->is_shadowed &&
+           in->parent->obj_id != YAFFS_OBJECTID_UNLINKED &&
+           in->parent->obj_id != YAFFS_OBJECTID_DELETED)
+               yaffs_update_oh(in, NULL, 0, 0, 0, NULL);
+
+       return YAFFS_OK;
+}
+
+int yaffs_flush_file(struct yaffs_obj *in, int update_time, int data_sync)
+{
+       if (!in->dirty)
+               return YAFFS_OK;
+
+       yaffs_flush_file_cache(in);
+
+       if (data_sync)
+               return YAFFS_OK;
+
+       if (update_time)
+               yaffs_load_current_time(in, 0, 0);
+
+       return (yaffs_update_oh(in, NULL, 0, 0, 0, NULL) >= 0) ?
+                               YAFFS_OK : YAFFS_FAIL;
+}
+
+
+/* yaffs_del_file deletes the whole file data
+ * and the inode associated with the file.
+ * It does not delete the links associated with the file.
+ */
+static int yaffs_unlink_file_if_needed(struct yaffs_obj *in)
+{
+       int ret_val;
+       int del_now = 0;
+       struct yaffs_dev *dev = in->my_dev;
+
+       if (!in->my_inode)
+               del_now = 1;
+
+       if (del_now) {
+               ret_val =
+                   yaffs_change_obj_name(in, in->my_dev->del_dir,
+                                         _Y("deleted"), 0, 0);
+               yaffs_trace(YAFFS_TRACE_TRACING,
+                       "yaffs: immediate deletion of file %d",
+                       in->obj_id);
+               in->deleted = 1;
+               in->my_dev->n_deleted_files++;
+               if (dev->param.disable_soft_del || dev->param.is_yaffs2)
+                       yaffs_resize_file(in, 0);
+               yaffs_soft_del_file(in);
+       } else {
+               ret_val =
+                   yaffs_change_obj_name(in, in->my_dev->unlinked_dir,
+                                         _Y("unlinked"), 0, 0);
+       }
+       return ret_val;
+}
+
+int yaffs_del_file(struct yaffs_obj *in)
+{
+       int ret_val = YAFFS_OK;
+       int deleted;    /* Need to cache value on stack if in is freed */
+       struct yaffs_dev *dev = in->my_dev;
+
+       if (dev->param.disable_soft_del || dev->param.is_yaffs2)
+               yaffs_resize_file(in, 0);
+
+       if (in->n_data_chunks > 0) {
+               /* Use soft deletion if there is data in the file.
+                * That won't be the case if it has been resized to zero.
+                */
+               if (!in->unlinked)
+                       ret_val = yaffs_unlink_file_if_needed(in);
+
+               deleted = in->deleted;
+
+               if (ret_val == YAFFS_OK && in->unlinked && !in->deleted) {
+                       in->deleted = 1;
+                       deleted = 1;
+                       in->my_dev->n_deleted_files++;
+                       yaffs_soft_del_file(in);
+               }
+               return deleted ? YAFFS_OK : YAFFS_FAIL;
+       } else {
+               /* The file has no data chunks so we toss it immediately */
+               yaffs_free_tnode(in->my_dev, in->variant.file_variant.top);
+               in->variant.file_variant.top = NULL;
+               yaffs_generic_obj_del(in);
+
+               return YAFFS_OK;
+       }
+}
+
+int yaffs_is_non_empty_dir(struct yaffs_obj *obj)
+{
+       return (obj &&
+               obj->variant_type == YAFFS_OBJECT_TYPE_DIRECTORY) &&
+               !(list_empty(&obj->variant.dir_variant.children));
+}
+
+static int yaffs_del_dir(struct yaffs_obj *obj)
+{
+       /* First check that the directory is empty. */
+       if (yaffs_is_non_empty_dir(obj))
+               return YAFFS_FAIL;
+
+       return yaffs_generic_obj_del(obj);
+}
+
+static int yaffs_del_symlink(struct yaffs_obj *in)
+{
+       kfree(in->variant.symlink_variant.alias);
+       in->variant.symlink_variant.alias = NULL;
+
+       return yaffs_generic_obj_del(in);
+}
+
+static int yaffs_del_link(struct yaffs_obj *in)
+{
+       /* remove this hardlink from the list associated with the equivalent
+        * object
+        */
+       list_del_init(&in->hard_links);
+       return yaffs_generic_obj_del(in);
+}
+
+int yaffs_del_obj(struct yaffs_obj *obj)
+{
+       int ret_val = -1;
+
+       switch (obj->variant_type) {
+       case YAFFS_OBJECT_TYPE_FILE:
+               ret_val = yaffs_del_file(obj);
+               break;
+       case YAFFS_OBJECT_TYPE_DIRECTORY:
+               if (!list_empty(&obj->variant.dir_variant.dirty)) {
+                       yaffs_trace(YAFFS_TRACE_BACKGROUND,
+                               "Remove object %d from dirty directories",
+                               obj->obj_id);
+                       list_del_init(&obj->variant.dir_variant.dirty);
+               }
+               return yaffs_del_dir(obj);
+               break;
+       case YAFFS_OBJECT_TYPE_SYMLINK:
+               ret_val = yaffs_del_symlink(obj);
+               break;
+       case YAFFS_OBJECT_TYPE_HARDLINK:
+               ret_val = yaffs_del_link(obj);
+               break;
+       case YAFFS_OBJECT_TYPE_SPECIAL:
+               ret_val = yaffs_generic_obj_del(obj);
+               break;
+       case YAFFS_OBJECT_TYPE_UNKNOWN:
+               ret_val = 0;
+               break;          /* should not happen. */
+       }
+       return ret_val;
+}
+
+static int yaffs_unlink_worker(struct yaffs_obj *obj)
+{
+       int del_now = 0;
+
+       if (!obj)
+               return YAFFS_FAIL;
+
+       if (!obj->my_inode)
+               del_now = 1;
+
+       yaffs_update_parent(obj->parent);
+
+       if (obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK) {
+               return yaffs_del_link(obj);
+       } else if (!list_empty(&obj->hard_links)) {
+               /* Curve ball: We're unlinking an object that has a hardlink.
+                *
+                * This problem arises because we are not strictly following
+                * The Linux link/inode model.
+                *
+                * We can't really delete the object.
+                * Instead, we do the following:
+                * - Select a hardlink.
+                * - Unhook it from the hard links
+                * - Move it from its parent directory so that the rename works.
+                * - Rename the object to the hardlink's name.
+                * - Delete the hardlink
+                */
+
+               struct yaffs_obj *hl;
+               struct yaffs_obj *parent;
+               int ret_val;
+               YCHAR name[YAFFS_MAX_NAME_LENGTH + 1];
+
+               hl = list_entry(obj->hard_links.next, struct yaffs_obj,
+                               hard_links);
+
+               yaffs_get_obj_name(hl, name, YAFFS_MAX_NAME_LENGTH + 1);
+               parent = hl->parent;
+
+               list_del_init(&hl->hard_links);
+
+               yaffs_add_obj_to_dir(obj->my_dev->unlinked_dir, hl);
+
+               ret_val = yaffs_change_obj_name(obj, parent, name, 0, 0);
+
+               if (ret_val == YAFFS_OK)
+                       ret_val = yaffs_generic_obj_del(hl);
+
+               return ret_val;
+
+       } else if (del_now) {
+               switch (obj->variant_type) {
+               case YAFFS_OBJECT_TYPE_FILE:
+                       return yaffs_del_file(obj);
+                       break;
+               case YAFFS_OBJECT_TYPE_DIRECTORY:
+                       list_del_init(&obj->variant.dir_variant.dirty);
+                       return yaffs_del_dir(obj);
+                       break;
+               case YAFFS_OBJECT_TYPE_SYMLINK:
+                       return yaffs_del_symlink(obj);
+                       break;
+               case YAFFS_OBJECT_TYPE_SPECIAL:
+                       return yaffs_generic_obj_del(obj);
+                       break;
+               case YAFFS_OBJECT_TYPE_HARDLINK:
+               case YAFFS_OBJECT_TYPE_UNKNOWN:
+               default:
+                       return YAFFS_FAIL;
+               }
+       } else if (yaffs_is_non_empty_dir(obj)) {
+               return YAFFS_FAIL;
+       } else {
+               return yaffs_change_obj_name(obj, obj->my_dev->unlinked_dir,
+                                               _Y("unlinked"), 0, 0);
+       }
+}
+
+static int yaffs_unlink_obj(struct yaffs_obj *obj)
+{
+       if (obj && obj->unlink_allowed)
+               return yaffs_unlink_worker(obj);
+
+       return YAFFS_FAIL;
+}
+
+int yaffs_unlinker(struct yaffs_obj *dir, const YCHAR *name)
+{
+       struct yaffs_obj *obj;
+
+       obj = yaffs_find_by_name(dir, name);
+       return yaffs_unlink_obj(obj);
+}
+
+/* Note:
+ * If old_name is NULL then we take old_dir as the object to be renamed.
+ */
+int yaffs_rename_obj(struct yaffs_obj *old_dir, const YCHAR *old_name,
+                    struct yaffs_obj *new_dir, const YCHAR *new_name)
+{
+       struct yaffs_obj *obj = NULL;
+       struct yaffs_obj *existing_target = NULL;
+       int force = 0;
+       int result;
+       struct yaffs_dev *dev;
+
+       if (!old_dir || old_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
+               BUG();
+               return YAFFS_FAIL;
+       }
+       if (!new_dir || new_dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
+               BUG();
+               return YAFFS_FAIL;
+       }
+
+       dev = old_dir->my_dev;
+
+#ifdef CONFIG_YAFFS_CASE_INSENSITIVE
+       /* Special case for case insemsitive systems.
+        * While look-up is case insensitive, the name isn't.
+        * Therefore we might want to change x.txt to X.txt
+        */
+       if (old_dir == new_dir &&
+               old_name && new_name &&
+               yaffs_strcmp(old_name, new_name) == 0)
+               force = 1;
+#endif
+
+       if (yaffs_strnlen(new_name, YAFFS_MAX_NAME_LENGTH + 1) >
+           YAFFS_MAX_NAME_LENGTH)
+               /* ENAMETOOLONG */
+               return YAFFS_FAIL;
+
+       if (old_name)
+               obj = yaffs_find_by_name(old_dir, old_name);
+       else{
+               obj = old_dir;
+               old_dir = obj->parent;
+       }
+
+       if (obj && obj->rename_allowed) {
+               /* Now handle an existing target, if there is one */
+               existing_target = yaffs_find_by_name(new_dir, new_name);
+               if (yaffs_is_non_empty_dir(existing_target)) {
+                       return YAFFS_FAIL;      /* ENOTEMPTY */
+               } else if (existing_target && existing_target != obj) {
+                       /* Nuke the target first, using shadowing,
+                        * but only if it isn't the same object.
+                        *
+                        * Note we must disable gc here otherwise it can mess
+                        * up the shadowing.
+                        *
+                        */
+                       dev->gc_disable = 1;
+                       yaffs_change_obj_name(obj, new_dir, new_name, force,
+                                             existing_target->obj_id);
+                       existing_target->is_shadowed = 1;
+                       yaffs_unlink_obj(existing_target);
+                       dev->gc_disable = 0;
+               }
+
+               result = yaffs_change_obj_name(obj, new_dir, new_name, 1, 0);
+
+               yaffs_update_parent(old_dir);
+               if (new_dir != old_dir)
+                       yaffs_update_parent(new_dir);
+
+               return result;
+       }
+       return YAFFS_FAIL;
+}
+
+/*----------------------- Initialisation Scanning ---------------------- */
+
+void yaffs_handle_shadowed_obj(struct yaffs_dev *dev, int obj_id,
+                              int backward_scanning)
+{
+       struct yaffs_obj *obj;
+
+       if (backward_scanning) {
+               /* Handle YAFFS2 case (backward scanning)
+                * If the shadowed object exists then ignore.
+                */
+               obj = yaffs_find_by_number(dev, obj_id);
+               if (obj)
+                       return;
+       }
+
+       /* Let's create it (if it does not exist) assuming it is a file so that
+        * it can do shrinking etc.
+        * We put it in unlinked dir to be cleaned up after the scanning
+        */
+       obj =
+           yaffs_find_or_create_by_number(dev, obj_id, YAFFS_OBJECT_TYPE_FILE);
+       if (!obj)
+               return;
+       obj->is_shadowed = 1;
+       yaffs_add_obj_to_dir(dev->unlinked_dir, obj);
+       obj->variant.file_variant.shrink_size = 0;
+       obj->valid = 1;         /* So that we don't read any other info. */
+}
+
+void yaffs_link_fixup(struct yaffs_dev *dev, struct list_head *hard_list)
+{
+       struct list_head *lh;
+       struct list_head *save;
+       struct yaffs_obj *hl;
+       struct yaffs_obj *in;
+
+       list_for_each_safe(lh, save, hard_list) {
+               hl = list_entry(lh, struct yaffs_obj, hard_links);
+               in = yaffs_find_by_number(dev,
+                                       hl->variant.hardlink_variant.equiv_id);
+
+               if (in) {
+                       /* Add the hardlink pointers */
+                       hl->variant.hardlink_variant.equiv_obj = in;
+                       list_add(&hl->hard_links, &in->hard_links);
+               } else {
+                       /* Todo Need to report/handle this better.
+                        * Got a problem... hardlink to a non-existant object
+                        */
+                       hl->variant.hardlink_variant.equiv_obj = NULL;
+                       INIT_LIST_HEAD(&hl->hard_links);
+               }
+       }
+}
+
+static void yaffs_strip_deleted_objs(struct yaffs_dev *dev)
+{
+       /*
+        *  Sort out state of unlinked and deleted objects after scanning.
+        */
+       struct list_head *i;
+       struct list_head *n;
+       struct yaffs_obj *l;
+
+       if (dev->read_only)
+               return;
+
+       /* Soft delete all the unlinked files */
+       list_for_each_safe(i, n,
+                          &dev->unlinked_dir->variant.dir_variant.children) {
+               l = list_entry(i, struct yaffs_obj, siblings);
+               yaffs_del_obj(l);
+       }
+
+       list_for_each_safe(i, n, &dev->del_dir->variant.dir_variant.children) {
+               l = list_entry(i, struct yaffs_obj, siblings);
+               yaffs_del_obj(l);
+       }
+}
+
+/*
+ * This code iterates through all the objects making sure that they are rooted.
+ * Any unrooted objects are re-rooted in lost+found.
+ * An object needs to be in one of:
+ * - Directly under deleted, unlinked
+ * - Directly or indirectly under root.
+ *
+ * Note:
+ *  This code assumes that we don't ever change the current relationships
+ *  between directories:
+ *   root_dir->parent == unlinked_dir->parent == del_dir->parent == NULL
+ *   lost-n-found->parent == root_dir
+ *
+ * This fixes the problem where directories might have inadvertently been
+ * deleted leaving the object "hanging" without being rooted in the
+ * directory tree.
+ */
+
+static int yaffs_has_null_parent(struct yaffs_dev *dev, struct yaffs_obj *obj)
+{
+       return (obj == dev->del_dir ||
+               obj == dev->unlinked_dir || obj == dev->root_dir);
+}
+
+static void yaffs_fix_hanging_objs(struct yaffs_dev *dev)
+{
+       struct yaffs_obj *obj;
+       struct yaffs_obj *parent;
+       int i;
+       struct list_head *lh;
+       struct list_head *n;
+       int depth_limit;
+       int hanging;
+
+       if (dev->read_only)
+               return;
+
+       /* Iterate through the objects in each hash entry,
+        * looking at each object.
+        * Make sure it is rooted.
+        */
+
+       for (i = 0; i < YAFFS_NOBJECT_BUCKETS; i++) {
+               list_for_each_safe(lh, n, &dev->obj_bucket[i].list) {
+                       obj = list_entry(lh, struct yaffs_obj, hash_link);
+                       parent = obj->parent;
+
+                       if (yaffs_has_null_parent(dev, obj)) {
+                               /* These directories are not hanging */
+                               hanging = 0;
+                       } else if (!parent ||
+                                  parent->variant_type !=
+                                  YAFFS_OBJECT_TYPE_DIRECTORY) {
+                               hanging = 1;
+                       } else if (yaffs_has_null_parent(dev, parent)) {
+                               hanging = 0;
+                       } else {
+                               /*
+                                * Need to follow the parent chain to
+                                * see if it is hanging.
+                                */
+                               hanging = 0;
+                               depth_limit = 100;
+
+                               while (parent != dev->root_dir &&
+                                      parent->parent &&
+                                      parent->parent->variant_type ==
+                                      YAFFS_OBJECT_TYPE_DIRECTORY &&
+                                      depth_limit > 0) {
+                                       parent = parent->parent;
+                                       depth_limit--;
+                               }
+                               if (parent != dev->root_dir)
+                                       hanging = 1;
+                       }
+                       if (hanging) {
+                               yaffs_trace(YAFFS_TRACE_SCAN,
+                                       "Hanging object %d moved to lost and found",
+                                       obj->obj_id);
+                               yaffs_add_obj_to_dir(dev->lost_n_found, obj);
+                       }
+               }
+       }
+}
+
+/*
+ * Delete directory contents for cleaning up lost and found.
+ */
+static void yaffs_del_dir_contents(struct yaffs_obj *dir)
+{
+       struct yaffs_obj *obj;
+       struct list_head *lh;
+       struct list_head *n;
+
+       if (dir->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY)
+               BUG();
+
+       list_for_each_safe(lh, n, &dir->variant.dir_variant.children) {
+               obj = list_entry(lh, struct yaffs_obj, siblings);
+               if (obj->variant_type == YAFFS_OBJECT_TYPE_DIRECTORY)
+                       yaffs_del_dir_contents(obj);
+               yaffs_trace(YAFFS_TRACE_SCAN,
+                       "Deleting lost_found object %d",
+                       obj->obj_id);
+               yaffs_unlink_obj(obj);
+       }
+}
+
+static void yaffs_empty_l_n_f(struct yaffs_dev *dev)
+{
+       yaffs_del_dir_contents(dev->lost_n_found);
+}
+
+
+struct yaffs_obj *yaffs_find_by_name(struct yaffs_obj *directory,
+                                    const YCHAR *name)
+{
+       int sum;
+       struct list_head *i;
+       YCHAR buffer[YAFFS_MAX_NAME_LENGTH + 1];
+       struct yaffs_obj *l;
+
+       if (!name)
+               return NULL;
+
+       if (!directory) {
+               yaffs_trace(YAFFS_TRACE_ALWAYS,
+                       "tragedy: yaffs_find_by_name: null pointer directory"
+                       );
+               BUG();
+               return NULL;
+       }
+       if (directory->variant_type != YAFFS_OBJECT_TYPE_DIRECTORY) {
+               yaffs_trace(YAFFS_TRACE_ALWAYS,
+                       "tragedy: yaffs_find_by_name: non-directory"
+                       );
+               BUG();
+       }
+
+       sum = yaffs_calc_name_sum(name);
+
+       list_for_each(i, &directory->variant.dir_variant.children) {
+               l = list_entry(i, struct yaffs_obj, siblings);
+
+               if (l->parent != directory)
+                       BUG();
+
+               yaffs_check_obj_details_loaded(l);
+
+               /* Special case for lost-n-found */
+               if (l->obj_id == YAFFS_OBJECTID_LOSTNFOUND) {
+                       if (!yaffs_strcmp(name, YAFFS_LOSTNFOUND_NAME))
+                               return l;
+               } else if (l->sum == sum || l->hdr_chunk <= 0) {
+                       /* LostnFound chunk called Objxxx
+                        * Do a real check
+                        */
+                       yaffs_get_obj_name(l, buffer,
+                               YAFFS_MAX_NAME_LENGTH + 1);
+                       if (!yaffs_strncmp(name, buffer, YAFFS_MAX_NAME_LENGTH))
+                               return l;
+               }
+       }
+       return NULL;
+}
+
+/* GetEquivalentObject dereferences any hard links to get to the
+ * actual object.
+ */
+
+struct yaffs_obj *yaffs_get_equivalent_obj(struct yaffs_obj *obj)
+{
+       if (obj && obj->variant_type == YAFFS_OBJECT_TYPE_HARDLINK) {
+               obj = obj->variant.hardlink_variant.equiv_obj;
+               yaffs_check_obj_details_loaded(obj);
+       }
+       return obj;
+}
+
+/*
+ *  A note or two on object names.
+ *  * If the object name is missing, we then make one up in the form objnnn
+ *
+ *  * ASCII names are stored in the object header's name field from byte zero
+ *  * Unicode names are historically stored starting from byte zero.
+ *
+ * Then there are automatic Unicode names...
+ * The purpose of these is to save names in a way that can be read as
+ * ASCII or Unicode names as appropriate, thus allowing a Unicode and ASCII
+ * system to share files.
+ *
+ * These automatic unicode are stored slightly differently...
+ *  - If the name can fit in the ASCII character space then they are saved as
+ *    ascii names as per above.
+ *  - If the name needs Unicode then the name is saved in Unicode
+ *    starting at oh->name[1].
+
+ */
+static void yaffs_fix_null_name(struct yaffs_obj *obj, YCHAR *name,
+                               int buffer_size)
+{
+       /* Create an object name if we could not find one. */
+       if (yaffs_strnlen(name, YAFFS_MAX_NAME_LENGTH) == 0) {
+               YCHAR local_name[20];
+               YCHAR num_string[20];
+               YCHAR *x = &num_string[19];
+               unsigned v = obj->obj_id;
+               num_string[19] = 0;
+               while (v > 0) {
+                       x--;
+                       *x = '0' + (v % 10);
+                       v /= 10;
+               }
+               /* make up a name */
+               yaffs_strcpy(local_name, YAFFS_LOSTNFOUND_PREFIX);
+               yaffs_strcat(local_name, x);
+               yaffs_strncpy(name, local_name, buffer_size - 1);
+       }
+}
+
+int yaffs_get_obj_name(struct yaffs_obj *obj, YCHAR *name, int buffer_size)
+{
+       memset(name, 0, buffer_size * sizeof(YCHAR));
+       yaffs_check_obj_details_loaded(obj);
+       if (obj->obj_id == YAFFS_OBJECTID_LOSTNFOUND) {
+               yaffs_strncpy(name, YAFFS_LOSTNFOUND_NAME, buffer_size - 1);
+       } else if (obj->short_name[0]) {
+               yaffs_strcpy(name, obj->short_name);
+       } else if (obj->hdr_chunk > 0) {
+               u8 *buffer = yaffs_get_temp_buffer(obj->my_dev);
+
+               struct yaffs_obj_hdr *oh = (struct yaffs_obj_hdr *)buffer;
+
+               memset(buffer, 0, obj->my_dev->data_bytes_per_chunk);
+
+               if (obj->hdr_chunk > 0) {
+                       yaffs_rd_chunk_tags_nand(obj->my_dev,
+                                                obj->hdr_chunk,
+                                                buffer, NULL);
+               }
+               yaffs_load_name_from_oh(obj->my_dev, name, oh->name,
+                                       buffer_size);
+
+               yaffs_release_temp_buffer(obj->my_dev, buffer);
+       }
+
+       yaffs_fix_null_name(obj, name, buffer_size);
+
+       return yaffs_strnlen(name, YAFFS_MAX_NAME_LENGTH);
+}
+
+loff_t yaffs_get_obj_length(struct yaffs_obj *obj)
+{
+       /* Dereference any hard linking */
+       obj = yaffs_get_equivalent_obj(obj);
+
+       if (obj->variant_type == YAFFS_OBJECT_TYPE_FILE)
+               return obj->variant.file_variant.file_size;
+       if (obj->variant_type == YAFFS_OBJECT_TYPE_SYMLINK) {
+               if (!obj->variant.symlink_variant.alias)
+                       return 0;
+               return yaffs_strnlen(obj->variant.symlink_variant.alias,
+                                    YAFFS_MAX_ALIAS_LENGTH);
+       } else {
+               /* Only a directory should drop through to here */
+               return obj->my_dev->data_bytes_per_chunk;
+       }
+}
+
+int yaffs_get_obj_link_count(struct yaffs_obj *obj)
+{
+       int count = 0;
+       struct list_head *i;
+
+       if (!obj->unlinked)
+               count++;        /* the object itself */
+
+       list_for_each(i, &obj->hard_links)
+           count++;            /* add the hard links; */
+
+       return count;
+}
+
+int yaffs_get_obj_inode(struct yaffs_obj *obj)
+{
+       obj = yaffs_get_equivalent_obj(obj);
+
+       return obj->obj_id;
+}
+
+unsigned yaffs_get_obj_type(struct yaffs_obj *obj)
+{
+       obj = yaffs_get_equivalent_obj(obj);
+
+       switch (obj->variant_type) {
+       case YAFFS_OBJECT_TYPE_FILE:
+               return DT_REG;
+               break;
+       case YAFFS_OBJECT_TYPE_DIRECTORY:
+               return DT_DIR;
+               break;
+       case YAFFS_OBJECT_TYPE_SYMLINK:
+               return DT_LNK;
+               break;
+       case YAFFS_OBJECT_TYPE_HARDLINK:
+               return DT_REG;
+               break;
+       case YAFFS_OBJECT_TYPE_SPECIAL:
+               if (S_ISFIFO(obj->yst_mode))
+                       return DT_FIFO;
+               if (S_ISCHR(obj->yst_mode))
+                       return DT_CHR;
+               if (S_ISBLK(obj->yst_mode))
+                       return DT_BLK;
+               if (S_ISSOCK(obj->yst_mode))
+                       return DT_SOCK;
+               return DT_REG;
+               break;
+       default:
+               return DT_REG;
+               break;
+       }
+}
+
+YCHAR *yaffs_get_symlink_alias(struct yaffs_obj *obj)
+{
+       obj = yaffs_get_equivalent_obj(obj);
+       if (obj->variant_type == YAFFS_OBJECT_TYPE_SYMLINK)
+               return yaffs_clone_str(obj->variant.symlink_variant.alias);
+       else
+               return yaffs_clone_str(_Y(""));
+}
+
+/*--------------------------- Initialisation code -------------------------- */
+
+static int yaffs_check_dev_fns(const struct yaffs_dev *dev)
+{
+       /* Common functions, gotta have */
+       if (!dev->param.erase_fn || !dev->param.initialise_flash_fn)
+               return 0;
+
+       /* Can use the "with tags" style interface for yaffs1 or yaffs2 */
+       if (dev->param.write_chunk_tags_fn &&
+           dev->param.read_chunk_tags_fn &&
+           !dev->param.write_chunk_fn &&
+           !dev->param.read_chunk_fn &&
+           dev->param.bad_block_fn && dev->param.query_block_fn)
+               return 1;
+
+       /* Can use the "spare" style interface for yaffs1 */
+       if (!dev->param.is_yaffs2 &&
+           !dev->param.write_chunk_tags_fn &&
+           !dev->param.read_chunk_tags_fn &&
+           dev->param.write_chunk_fn &&
+           dev->param.read_chunk_fn &&
+           !dev->param.bad_block_fn && !dev->param.query_block_fn)
+               return 1;
+
+       return 0;               /* bad */
+}
+
+static int yaffs_create_initial_dir(struct yaffs_dev *dev)
+{
+       /* Initialise the unlinked, deleted, root and lost+found directories */
+       dev->lost_n_found = dev->root_dir = NULL;
+       dev->unlinked_dir = dev->del_dir = NULL;
+       dev->unlinked_dir =
+           yaffs_create_fake_dir(dev, YAFFS_OBJECTID_UNLINKED, S_IFDIR);
+       dev->del_dir =
+           yaffs_create_fake_dir(dev, YAFFS_OBJECTID_DELETED, S_IFDIR);
+       dev->root_dir =
+           yaffs_create_fake_dir(dev, YAFFS_OBJECTID_ROOT,
+                                 YAFFS_ROOT_MODE | S_IFDIR);
+       dev->lost_n_found =
+           yaffs_create_fake_dir(dev, YAFFS_OBJECTID_LOSTNFOUND,
+                                 YAFFS_LOSTNFOUND_MODE | S_IFDIR);
+
+       if (dev->lost_n_found && dev->root_dir && dev->unlinked_dir
+           && dev->del_dir) {
+               yaffs_add_obj_to_dir(dev->root_dir, dev->lost_n_found);
+               return YAFFS_OK;
+       }
+       return YAFFS_FAIL;
+}
+
+int yaffs_guts_initialise(struct yaffs_dev *dev)
+{
+       int init_failed = 0;
+       unsigned x;
+       int bits;
+
+       yaffs_trace(YAFFS_TRACE_TRACING, "yaffs: yaffs_guts_initialise()");
+
+       /* Check stuff that must be set */
+
+       if (!dev) {
+               yaffs_trace(YAFFS_TRACE_ALWAYS,
+                       "yaffs: Need a device"
+                       );
+               return YAFFS_FAIL;
+       }
+
+       if (dev->is_mounted) {
+               yaffs_trace(YAFFS_TRACE_ALWAYS, "device already mounted");
+               return YAFFS_FAIL;
+       }
+
+       dev->internal_start_block = dev->param.start_block;
+       dev->internal_end_block = dev->param.end_block;
+       dev->block_offset = 0;
+       dev->chunk_offset = 0;
+       dev->n_free_chunks = 0;
+
+       dev->gc_block = 0;
+
+       if (dev->param.start_block == 0) {
+               dev->internal_start_block = dev->param.start_block + 1;
+               dev->internal_end_block = dev->param.end_block + 1;
+               dev->block_offset = 1;
+               dev->chunk_offset = dev->param.chunks_per_block;
+       }
+
+       /* Check geometry parameters. */
+
+       if ((!dev->param.inband_tags && dev->param.is_yaffs2 &&
+               dev->param.total_bytes_per_chunk < 1024) ||
+               (!dev->param.is_yaffs2 &&
+                       dev->param.total_bytes_per_chunk < 512) ||
+               (dev->param.inband_tags && !dev->param.is_yaffs2) ||
+                dev->param.chunks_per_block < 2 ||
+                dev->param.n_reserved_blocks < 2 ||
+               dev->internal_start_block <= 0 ||
+               dev->internal_end_block <= 0 ||
+               dev->internal_end_block <=
+               (dev->internal_start_block + dev->param.n_reserved_blocks + 2)
+               ) {
+               /* otherwise it is too small */
+               yaffs_trace(YAFFS_TRACE_ALWAYS,
+                       "NAND geometry problems: chunk size %d, type is yaffs%s, inband_tags %d ",
+                       dev->param.total_bytes_per_chunk,
+                       dev->param.is_yaffs2 ? "2" : "",
+                       dev->param.inband_tags);
+               return YAFFS_FAIL;
+       }
+
+       if (yaffs_init_nand(dev) != YAFFS_OK) {
+               yaffs_trace(YAFFS_TRACE_ALWAYS, "InitialiseNAND failed");
+               return YAFFS_FAIL;
+       }
+
+       /* Sort out space for inband tags, if required */
+       if (dev->param.inband_tags)
+               dev->data_bytes_per_chunk =
+                   dev->param.total_bytes_per_chunk -
+                   sizeof(struct yaffs_packed_tags2_tags_only);
+       else
+               dev->data_bytes_per_chunk = dev->param.total_bytes_per_chunk;
+
+       /* Got the right mix of functions? */
+       if (!yaffs_check_dev_fns(dev)) {
+               /* Function missing */
+               yaffs_trace(YAFFS_TRACE_ALWAYS,
+                       "device function(s) missing or wrong");
+
+               return YAFFS_FAIL;
+       }
+
+       /* Finished with most checks. Further checks happen later on too. */
+
+       dev->is_mounted = 1;
+
+       /* OK now calculate a few things for the device */
+
+       /*
+        *  Calculate all the chunk size manipulation numbers:
+        */
+       x = dev->data_bytes_per_chunk;
+       /* We always use dev->chunk_shift and dev->chunk_div */
+       dev->chunk_shift = calc_shifts(x);
+       x >>= dev->chunk_shift;
+       dev->chunk_div = x;
+       /* We only use chunk mask if chunk_div is 1 */
+       dev->chunk_mask = (1 << dev->chunk_shift) - 1;
+
+       /*
+        * Calculate chunk_grp_bits.
+        * We need to find the next power of 2 > than internal_end_block
+        */
+
+       x = dev->param.chunks_per_block * (dev->internal_end_block + 1);
+
+       bits = calc_shifts_ceiling(x);
+
+       /* Set up tnode width if wide tnodes are enabled. */
+       if (!dev->param.wide_tnodes_disabled) {
+               /* bits must be even so that we end up with 32-bit words */
+               if (bits & 1)
+                       bits++;
+               if (bits < 16)
+                       dev->tnode_width = 16;
+               else
+                       dev->tnode_width = bits;
+       } else {
+               dev->tnode_width = 16;
+       }
+
+       dev->tnode_mask = (1 << dev->tnode_width) - 1;
+
+       /* Level0 Tnodes are 16 bits or wider (if wide tnodes are enabled),
+        * so if the bitwidth of the
+        * chunk range we're using is greater than 16 we need
+        * to figure out chunk shift and chunk_grp_size
+        */
+
+       if (bits <= dev->tnode_width)
+               dev->chunk_grp_bits = 0;
+       else
+               dev->chunk_grp_bits = bits - dev->tnode_width;
+
+       dev->tnode_size = (dev->tnode_width * YAFFS_NTNODES_LEVEL0) / 8;
+       if (dev->tnode_size < sizeof(struct yaffs_tnode))
+               dev->tnode_size = sizeof(struct yaffs_tnode);
+
+       dev->chunk_grp_size = 1 << dev->chunk_grp_bits;
+
+       if (dev->param.chunks_per_block < dev->chunk_grp_size) {
+               /* We have a problem because the soft delete won't work if
+                * the chunk group size > chunks per block.
+                * This can be remedied by using larger "virtual blocks".
+                */
+               yaffs_trace(YAFFS_TRACE_ALWAYS, "chunk group too large");
+
+               return YAFFS_FAIL;
+       }
+
+       /* Finished verifying the device, continue with initialisation */
+
+       /* More device initialisation */
+       dev->all_gcs = 0;
+       dev->passive_gc_count = 0;
+       dev->oldest_dirty_gc_count = 0;
+       dev->bg_gcs = 0;
+       dev->gc_block_finder = 0;
+       dev->buffered_block = -1;
+       dev->doing_buffered_block_rewrite = 0;
+       dev->n_deleted_files = 0;
+       dev->n_bg_deletions = 0;
+       dev->n_unlinked_files = 0;
+       dev->n_ecc_fixed = 0;
+       dev->n_ecc_unfixed = 0;
+       dev->n_tags_ecc_fixed = 0;
+       dev->n_tags_ecc_unfixed = 0;
+       dev->n_erase_failures = 0;
+       dev->n_erased_blocks = 0;
+       dev->gc_disable = 0;
+       dev->has_pending_prioritised_gc = 1;
+               /* Assume the worst for now, will get fixed on first GC */
+       INIT_LIST_HEAD(&dev->dirty_dirs);
+       dev->oldest_dirty_seq = 0;
+       dev->oldest_dirty_block = 0;
+
+       /* Initialise temporary buffers and caches. */
+       if (!yaffs_init_tmp_buffers(dev))
+               init_failed = 1;
+
+       dev->cache = NULL;
+       dev->gc_cleanup_list = NULL;
+
+       if (!init_failed && dev->param.n_caches > 0) {
+               int i;
+               void *buf;
+               int cache_bytes =
+                   dev->param.n_caches * sizeof(struct yaffs_cache);
+
+               if (dev->param.n_caches > YAFFS_MAX_SHORT_OP_CACHES)
+                       dev->param.n_caches = YAFFS_MAX_SHORT_OP_CACHES;
+
+               dev->cache = kmalloc(cache_bytes, GFP_NOFS);
+
+               buf = (u8 *) dev->cache;
+
+               if (dev->cache)
+                       memset(dev->cache, 0, cache_bytes);
+
+               for (i = 0; i < dev->param.n_caches && buf; i++) {
+                       dev->cache[i].object = NULL;
+                       dev->cache[i].last_use = 0;
+                       dev->cache[i].dirty = 0;
+                       dev->cache[i].data = buf =
+                           kmalloc(dev->param.total_bytes_per_chunk, GFP_NOFS);
+               }
+               if (!buf)
+                       init_failed = 1;
+
+               dev->cache_last_use = 0;
+       }
+
+       dev->cache_hits = 0;
+
+       if (!init_failed) {
+               dev->gc_cleanup_list =
+                   kmalloc(dev->param.chunks_per_block * sizeof(u32),
+                                       GFP_NOFS);
+               if (!dev->gc_cleanup_list)
+                       init_failed = 1;
+       }
+
+       if (dev->param.is_yaffs2)
+               dev->param.use_header_file_size = 1;
+
+       if (!init_failed && !yaffs_init_blocks(dev))
+               init_failed = 1;
+
+       yaffs_init_tnodes_and_objs(dev);
+
+       if (!init_failed && !yaffs_create_initial_dir(dev))
+               init_failed = 1;
+
+       if (!init_failed && dev->param.is_yaffs2 &&
+               !dev->param.disable_summary &&
+               !yaffs_summary_init(dev))
+               init_failed = 1;
+
+       if (!init_failed) {
+               /* Now scan the flash. */
+               if (dev->param.is_yaffs2) {
+                       if (yaffs2_checkpt_restore(dev)) {
+                               yaffs_check_obj_details_loaded(dev->root_dir);
+                               yaffs_trace(YAFFS_TRACE_CHECKPOINT |
+                                       YAFFS_TRACE_MOUNT,
+                                       "yaffs: restored from checkpoint"
+                                       );
+                       } else {
+
+                               /* Clean up the mess caused by an aborted
+                                * checkpoint load then scan backwards.
+                                */
+                               yaffs_deinit_blocks(dev);
+
+                               yaffs_deinit_tnodes_and_objs(dev);
+
+                               dev->n_erased_blocks = 0;
+                               dev->n_free_chunks = 0;
+                               dev->alloc_block = -1;
+                               dev->alloc_page = -1;
+                               dev->n_deleted_files = 0;
+                               dev->n_unlinked_files = 0;
+                               dev->n_bg_deletions = 0;
+
+                               if (!init_failed && !yaffs_init_blocks(dev))
+                                       init_failed = 1;
+
+                               yaffs_init_tnodes_and_objs(dev);
+
+                               if (!init_failed
+                                   && !yaffs_create_initial_dir(dev))
+                                       init_failed = 1;
+
+                               if (!init_failed && !yaffs2_scan_backwards(dev))
+                                       init_failed = 1;
+                       }
+               } else if (!yaffs1_scan(dev)) {
+                       init_failed = 1;
+               }
+
+               yaffs_strip_deleted_objs(dev);
+               yaffs_fix_hanging_objs(dev);
+               if (dev->param.empty_lost_n_found)
+                       yaffs_empty_l_n_f(dev);
+       }
+
+       if (init_failed) {
+               /* Clean up the mess */
+               yaffs_trace(YAFFS_TRACE_TRACING,
+                 "yaffs: yaffs_guts_initialise() aborted.");
+
+               yaffs_deinitialise(dev);
+               return YAFFS_FAIL;
+       }
+
+       /* Zero out stats */
+       dev->n_page_reads = 0;
+       dev->n_page_writes = 0;
+       dev->n_erasures = 0;
+       dev->n_gc_copies = 0;
+       dev->n_retried_writes = 0;
+
+       dev->n_retired_blocks = 0;
+
+       yaffs_verify_free_chunks(dev);
+       yaffs_verify_blocks(dev);
+
+       /* Clean up any aborted checkpoint data */
+       if (!dev->is_checkpointed && dev->blocks_in_checkpt > 0)
+               yaffs2_checkpt_invalidate(dev);
+
+       yaffs_trace(YAFFS_TRACE_TRACING,
+         "yaffs: yaffs_guts_initialise() done.");
+       return YAFFS_OK;
+}
+
+void yaffs_deinitialise(struct yaffs_dev *dev)
+{
+       if (dev->is_mounted) {
+               int i;
+
+               yaffs_deinit_blocks(dev);
+               yaffs_deinit_tnodes_and_objs(dev);
+               yaffs_summary_deinit(dev);
+
+               if (dev->param.n_caches > 0 && dev->cache) {
+
+                       for (i = 0; i < dev->param.n_caches; i++) {
+                               kfree(dev->cache[i].data);
+                               dev->cache[i].data = NULL;
+                       }
+
+                       kfree(dev->cache);
+                       dev->cache = NULL;
+               }
+
+               kfree(dev->gc_cleanup_list);
+
+               for (i = 0; i < YAFFS_N_TEMP_BUFFERS; i++)
+                       kfree(dev->temp_buffer[i].buffer);
+
+               dev->is_mounted = 0;
+
+               if (dev->param.deinitialise_flash_fn)
+                       dev->param.deinitialise_flash_fn(dev);
+       }
+}
+
+int yaffs_count_free_chunks(struct yaffs_dev *dev)
+{
+       int n_free = 0;
+       int b;
+       struct yaffs_block_info *blk;
+
+       blk = dev->block_info;
+       for (b = dev->internal_start_block; b <= dev->internal_end_block; b++) {
+               switch (blk->block_state) {
+               case YAFFS_BLOCK_STATE_EMPTY:
+               case YAFFS_BLOCK_STATE_ALLOCATING:
+               case YAFFS_BLOCK_STATE_COLLECTING:
+               case YAFFS_BLOCK_STATE_FULL:
+                       n_free +=
+                           (dev->param.chunks_per_block - blk->pages_in_use +
+                            blk->soft_del_pages);
+                       break;
+               default:
+                       break;
+               }
+               blk++;
+       }
+       return n_free;
+}
+
+int yaffs_get_n_free_chunks(struct yaffs_dev *dev)
+{
+       /* This is what we report to the outside world */
+       int n_free;
+       int n_dirty_caches;
+       int blocks_for_checkpt;
+       int i;
+
+       n_free = dev->n_free_chunks;
+       n_free += dev->n_deleted_files;
+
+       /* Now count and subtract the number of dirty chunks in the cache. */
+
+       for (n_dirty_caches = 0, i = 0; i < dev->param.n_caches; i++) {
+               if (dev->cache[i].dirty)
+                       n_dirty_caches++;
+       }
+
+       n_free -= n_dirty_caches;
+
+       n_free -=
+           ((dev->param.n_reserved_blocks + 1) * dev->param.chunks_per_block);
+
+       /* Now figure checkpoint space and report that... */
+       blocks_for_checkpt = yaffs_calc_checkpt_blocks_required(dev);
+
+       n_free -= (blocks_for_checkpt * dev->param.chunks_per_block);
+
+       if (n_free < 0)
+               n_free = 0;
+
+       return n_free;
+}
+
+/*\
+ * Marshalling functions to get loff_t file sizes into aand out of
+ * object headers.
+ */
+void yaffs_oh_size_load(struct yaffs_obj_hdr *oh, loff_t fsize)
+{
+       oh->file_size_low = (fsize & 0xFFFFFFFF);
+       oh->file_size_high = ((fsize >> 32) & 0xFFFFFFFF);
+}
+
+loff_t yaffs_oh_to_size(struct yaffs_obj_hdr *oh)
+{
+       loff_t retval;
+
+       if (~(oh->file_size_high))
+               retval = (((loff_t) oh->file_size_high) << 32) |
+                       (((loff_t) oh->file_size_low) & 0xFFFFFFFF);
+       else
+               retval = (loff_t) oh->file_size_low;
+
+       return retval;
+}