--- /dev/null
+/*
+ * 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.
+ */
+
+/* Summaries write the useful part of the tags for the chunks in a block into an
+ * an array which is written to the last n chunks of the block.
+ * Reading the summaries gives all the tags for the block in one read. Much
+ * faster.
+ *
+ * Chunks holding summaries are marked with tags making it look like
+ * they are part of a fake file.
+ *
+ * The summary could also be used during gc.
+ *
+ */
+
+#include "yaffs_summary.h"
+#include "yaffs_packedtags2.h"
+#include "yaffs_nand.h"
+#include "yaffs_getblockinfo.h"
+#include "yaffs_bitmap.h"
+
+/*
+ * The summary is built up in an array of summary tags.
+ * This gets written to the last one or two (maybe more) chunks in a block.
+ * A summary header is written as the first part of each chunk of summary data.
+ * The summary header must match or the summary is rejected.
+ */
+
+/* Summary tags don't need the sequence number because that is redundant. */
+struct yaffs_summary_tags {
+ unsigned obj_id;
+ unsigned chunk_id;
+ unsigned n_bytes;
+};
+
+/* Summary header */
+struct yaffs_summary_header {
+ unsigned version; /* Must match current version */
+ unsigned block; /* Must be this block */
+ unsigned seq; /* Must be this sequence number */
+ unsigned sum; /* Just add up all the bytes in the tags */
+};
+
+
+static void yaffs_summary_clear(struct yaffs_dev *dev)
+{
+ if (!dev->sum_tags)
+ return;
+ memset(dev->sum_tags, 0, dev->chunks_per_summary *
+ sizeof(struct yaffs_summary_tags));
+}
+
+
+void yaffs_summary_deinit(struct yaffs_dev *dev)
+{
+ kfree(dev->sum_tags);
+ dev->sum_tags = NULL;
+ kfree(dev->gc_sum_tags);
+ dev->gc_sum_tags = NULL;
+ dev->chunks_per_summary = 0;
+}
+
+int yaffs_summary_init(struct yaffs_dev *dev)
+{
+ int sum_bytes;
+ int chunks_used; /* Number of chunks used by summary */
+ int sum_tags_bytes;
+
+ sum_bytes = dev->param.chunks_per_block *
+ sizeof(struct yaffs_summary_tags);
+
+ chunks_used = (sum_bytes + dev->data_bytes_per_chunk - 1)/
+ (dev->data_bytes_per_chunk -
+ sizeof(struct yaffs_summary_header));
+
+ dev->chunks_per_summary = dev->param.chunks_per_block - chunks_used;
+ sum_tags_bytes = sizeof(struct yaffs_summary_tags) *
+ dev->chunks_per_summary;
+ dev->sum_tags = kmalloc(sum_tags_bytes, GFP_NOFS);
+ dev->gc_sum_tags = kmalloc(sum_tags_bytes, GFP_NOFS);
+ if (!dev->sum_tags || !dev->gc_sum_tags) {
+ yaffs_summary_deinit(dev);
+ return YAFFS_FAIL;
+ }
+
+ yaffs_summary_clear(dev);
+
+ return YAFFS_OK;
+}
+
+static unsigned yaffs_summary_sum(struct yaffs_dev *dev)
+{
+ u8 *sum_buffer = (u8 *)dev->sum_tags;
+ int i;
+ unsigned sum = 0;
+
+ i = sizeof(struct yaffs_summary_tags) *
+ dev->chunks_per_summary;
+ while (i > 0) {
+ sum += *sum_buffer;
+ sum_buffer++;
+ i--;
+ }
+
+ return sum;
+}
+
+static int yaffs_summary_write(struct yaffs_dev *dev, int blk)
+{
+ struct yaffs_ext_tags tags;
+ u8 *buffer;
+ u8 *sum_buffer = (u8 *)dev->sum_tags;
+ int n_bytes;
+ int chunk_in_nand;
+ int chunk_in_block;
+ int result;
+ int this_tx;
+ struct yaffs_summary_header hdr;
+ int sum_bytes_per_chunk = dev->data_bytes_per_chunk - sizeof(hdr);
+ struct yaffs_block_info *bi = yaffs_get_block_info(dev, blk);
+
+ buffer = yaffs_get_temp_buffer(dev);
+ n_bytes = sizeof(struct yaffs_summary_tags) *
+ dev->chunks_per_summary;
+ memset(&tags, 0, sizeof(struct yaffs_ext_tags));
+ tags.obj_id = YAFFS_OBJECTID_SUMMARY;
+ tags.chunk_id = 1;
+ chunk_in_block = dev->chunks_per_summary;
+ chunk_in_nand = dev->alloc_block * dev->param.chunks_per_block +
+ dev->chunks_per_summary;
+ hdr.version = YAFFS_SUMMARY_VERSION;
+ hdr.block = blk;
+ hdr.seq = bi->seq_number;
+ hdr.sum = yaffs_summary_sum(dev);
+
+ do {
+ this_tx = n_bytes;
+ if (this_tx > sum_bytes_per_chunk)
+ this_tx = sum_bytes_per_chunk;
+ memcpy(buffer, &hdr, sizeof(hdr));
+ memcpy(buffer + sizeof(hdr), sum_buffer, this_tx);
+ tags.n_bytes = this_tx + sizeof(hdr);
+ result = yaffs_wr_chunk_tags_nand(dev, chunk_in_nand,
+ buffer, &tags);
+
+ if (result != YAFFS_OK)
+ break;
+ yaffs_set_chunk_bit(dev, blk, chunk_in_block);
+ bi->pages_in_use++;
+ dev->n_free_chunks--;
+
+ n_bytes -= this_tx;
+ sum_buffer += this_tx;
+ chunk_in_nand++;
+ chunk_in_block++;
+ tags.chunk_id++;
+ } while (result == YAFFS_OK && n_bytes > 0);
+ yaffs_release_temp_buffer(dev, buffer);
+
+
+ if (result == YAFFS_OK)
+ bi->has_summary = 1;
+
+
+ return result;
+}
+
+int yaffs_summary_read(struct yaffs_dev *dev,
+ struct yaffs_summary_tags *st,
+ int blk)
+{
+ struct yaffs_ext_tags tags;
+ u8 *buffer;
+ u8 *sum_buffer = (u8 *)st;
+ int n_bytes;
+ int chunk_id;
+ int chunk_in_nand;
+ int chunk_in_block;
+ int result;
+ int this_tx;
+ struct yaffs_summary_header hdr;
+ struct yaffs_block_info *bi = yaffs_get_block_info(dev, blk);
+ int sum_bytes_per_chunk = dev->data_bytes_per_chunk - sizeof(hdr);
+ int sum_tags_bytes;
+
+ sum_tags_bytes = sizeof(struct yaffs_summary_tags) *
+ dev->chunks_per_summary;
+ buffer = yaffs_get_temp_buffer(dev);
+ n_bytes = sizeof(struct yaffs_summary_tags) * dev->chunks_per_summary;
+ chunk_in_block = dev->chunks_per_summary;
+ chunk_in_nand = blk * dev->param.chunks_per_block +
+ dev->chunks_per_summary;
+ chunk_id = 1;
+ do {
+ this_tx = n_bytes;
+ if (this_tx > sum_bytes_per_chunk)
+ this_tx = sum_bytes_per_chunk;
+ result = yaffs_rd_chunk_tags_nand(dev, chunk_in_nand,
+ buffer, &tags);
+
+ if (tags.chunk_id != chunk_id ||
+ tags.obj_id != YAFFS_OBJECTID_SUMMARY ||
+ tags.chunk_used == 0 ||
+ tags.ecc_result > YAFFS_ECC_RESULT_FIXED ||
+ tags.n_bytes != (this_tx + sizeof(hdr)))
+ result = YAFFS_FAIL;
+ if (result != YAFFS_OK)
+ break;
+
+ if (st == dev->sum_tags) {
+ /* If we're scanning then update the block info */
+ yaffs_set_chunk_bit(dev, blk, chunk_in_block);
+ bi->pages_in_use++;
+ }
+ memcpy(&hdr, buffer, sizeof(hdr));
+ memcpy(sum_buffer, buffer + sizeof(hdr), this_tx);
+ n_bytes -= this_tx;
+ sum_buffer += this_tx;
+ chunk_in_nand++;
+ chunk_in_block++;
+ chunk_id++;
+ } while (result == YAFFS_OK && n_bytes > 0);
+ yaffs_release_temp_buffer(dev, buffer);
+
+ if (result == YAFFS_OK) {
+ /* Verify header */
+ if (hdr.version != YAFFS_SUMMARY_VERSION ||
+ hdr.block != blk ||
+ hdr.seq != bi->seq_number ||
+ hdr.sum != yaffs_summary_sum(dev))
+ result = YAFFS_FAIL;
+ }
+
+ if (st == dev->sum_tags && result == YAFFS_OK)
+ bi->has_summary = 1;
+
+ return result;
+}
+
+int yaffs_summary_add(struct yaffs_dev *dev,
+ struct yaffs_ext_tags *tags,
+ int chunk_in_nand)
+{
+ struct yaffs_packed_tags2_tags_only tags_only;
+ struct yaffs_summary_tags *sum_tags;
+ int block_in_nand = chunk_in_nand / dev->param.chunks_per_block;
+ int chunk_in_block = chunk_in_nand % dev->param.chunks_per_block;
+
+ if (!dev->sum_tags)
+ return YAFFS_OK;
+
+ if (chunk_in_block >= 0 && chunk_in_block < dev->chunks_per_summary) {
+ yaffs_pack_tags2_tags_only(&tags_only, tags);
+ sum_tags = &dev->sum_tags[chunk_in_block];
+ sum_tags->chunk_id = tags_only.chunk_id;
+ sum_tags->n_bytes = tags_only.n_bytes;
+ sum_tags->obj_id = tags_only.obj_id;
+
+ if (chunk_in_block == dev->chunks_per_summary - 1) {
+ /* Time to write out the summary */
+ yaffs_summary_write(dev, block_in_nand);
+ yaffs_summary_clear(dev);
+ yaffs_skip_rest_of_block(dev);
+ }
+ }
+ return YAFFS_OK;
+}
+
+int yaffs_summary_fetch(struct yaffs_dev *dev,
+ struct yaffs_ext_tags *tags,
+ int chunk_in_block)
+{
+ struct yaffs_packed_tags2_tags_only tags_only;
+ struct yaffs_summary_tags *sum_tags;
+ if (chunk_in_block >= 0 && chunk_in_block < dev->chunks_per_summary) {
+ sum_tags = &dev->sum_tags[chunk_in_block];
+ tags_only.chunk_id = sum_tags->chunk_id;
+ tags_only.n_bytes = sum_tags->n_bytes;
+ tags_only.obj_id = sum_tags->obj_id;
+ yaffs_unpack_tags2_tags_only(tags, &tags_only);
+ return YAFFS_OK;
+ }
+ return YAFFS_FAIL;
+}
+
+void yaffs_summary_gc(struct yaffs_dev *dev, int blk)
+{
+ struct yaffs_block_info *bi = yaffs_get_block_info(dev, blk);
+ int i;
+
+ if (!bi->has_summary)
+ return;
+
+ for (i = dev->chunks_per_summary;
+ i < dev->param.chunks_per_block;
+ i++) {
+ if (yaffs_check_chunk_bit(dev, blk, i)) {
+ yaffs_clear_chunk_bit(dev, blk, i);
+ bi->pages_in_use--;
+ dev->n_free_chunks++;
+ }
+ }
+}
projects / 15.05 / openwrt.git / blobdiff