[PATCH 03/10] Add yaffs2 file system: checkpoint streaming

[Charles Manning <cdhmanning@gmail.com>]

Signed-off-by: Charles Manning <cdhmanning@gmail.com>
---
 fs/yaffs2/yaffs_checkptrw.c |  408 +++++++++++++++++++++++++++++++++++++++++++
 fs/yaffs2/yaffs_checkptrw.h |   33 ++++
 2 files changed, 441 insertions(+), 0 deletions(-)
 create mode 100644 fs/yaffs2/yaffs_checkptrw.c
 create mode 100644 fs/yaffs2/yaffs_checkptrw.h

diff --git a/fs/yaffs2/yaffs_checkptrw.c b/fs/yaffs2/yaffs_checkptrw.c
new file mode 100644
index 0000000..997a618
--- /dev/null
+++ b/fs/yaffs2/yaffs_checkptrw.c
@@ -0,0 +1,408 @@
+/*
+ * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2011 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include "yaffs_checkptrw.h"
+#include "yaffs_getblockinfo.h"
+
+static int yaffs2_checkpt_space_ok(struct yaffs_dev *dev)
+{
+	int blocks_avail = dev->n_erased_blocks - dev->param.n_reserved_blocks;
+
+	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+		"checkpt blocks_avail = %d", blocks_avail);
+
+	return (blocks_avail <= 0) ? 0 : 1;
+}
+
+static int yaffs_checkpt_erase(struct yaffs_dev *dev)
+{
+	int i;
+
+	if (!dev->param.erase_fn)
+		return 0;
+	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+		"checking blocks %d to %d",
+		dev->internal_start_block, dev->internal_end_block);
+
+	for (i = dev->internal_start_block; i <= dev->internal_end_block; i++) {
+		struct yaffs_block_info *bi = yaffs_get_block_info(dev, i);
+		if (bi->block_state == YAFFS_BLOCK_STATE_CHECKPOINT) {
+			yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+			"erasing checkpt block %d", i);
+
+			dev->n_erasures++;
+
+			if (dev->param.
+			    erase_fn(dev,
+				     i - dev->block_offset /* realign */)) {
+				bi->block_state = YAFFS_BLOCK_STATE_EMPTY;
+				dev->n_erased_blocks++;
+				dev->n_free_chunks +=
+				    dev->param.chunks_per_block;
+			} else {
+				dev->param.bad_block_fn(dev, i);
+				bi->block_state = YAFFS_BLOCK_STATE_DEAD;
+			}
+		}
+	}
+
+	dev->blocks_in_checkpt = 0;
+
+	return 1;
+}
+
+static void yaffs2_checkpt_find_erased_block(struct yaffs_dev *dev)
+{
+	int i;
+	int blocks_avail = dev->n_erased_blocks - dev->param.n_reserved_blocks;
+
+	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+		"allocating checkpt block: erased %d reserved %d avail %d next %d ",
+		dev->n_erased_blocks, dev->param.n_reserved_blocks,
+		blocks_avail, dev->checkpt_next_block);
+
+	if (dev->checkpt_next_block >= 0 &&
+	    dev->checkpt_next_block <= dev->internal_end_block &&
+	    blocks_avail > 0) {
+
+		for (i = dev->checkpt_next_block; i <= dev->internal_end_block;
+		     i++) {
+			struct yaffs_block_info *bi =
+			    yaffs_get_block_info(dev, i);
+			if (bi->block_state == YAFFS_BLOCK_STATE_EMPTY) {
+				dev->checkpt_next_block = i + 1;
+				dev->checkpt_cur_block = i;
+				yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+					"allocating checkpt block %d", i);
+				return;
+			}
+		}
+	}
+	yaffs_trace(YAFFS_TRACE_CHECKPOINT, "out of checkpt blocks");
+
+	dev->checkpt_next_block = -1;
+	dev->checkpt_cur_block = -1;
+}
+
+static void yaffs2_checkpt_find_block(struct yaffs_dev *dev)
+{
+	int i;
+	struct yaffs_ext_tags tags;
+
+	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+		"find next checkpt block: start:  blocks %d next %d",
+		dev->blocks_in_checkpt, dev->checkpt_next_block);
+
+	if (dev->blocks_in_checkpt < dev->checkpt_max_blocks)
+		for (i = dev->checkpt_next_block; i <= dev->internal_end_block;
+		     i++) {
+			int chunk = i * dev->param.chunks_per_block;
+			int realigned_chunk = chunk - dev->chunk_offset;
+
+			dev->param.read_chunk_tags_fn(dev, realigned_chunk,
+						      NULL, &tags);
+			yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+				"find next checkpt block: search: block %d oid %d seq %d eccr %d",
+				i, tags.obj_id, tags.seq_number,
+				tags.ecc_result);
+
+			if (tags.seq_number == YAFFS_SEQUENCE_CHECKPOINT_DATA) {
+				/* Right kind of block */
+				dev->checkpt_next_block = tags.obj_id;
+				dev->checkpt_cur_block = i;
+				dev->checkpt_block_list[dev->
+							blocks_in_checkpt] = i;
+				dev->blocks_in_checkpt++;
+				yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+					"found checkpt block %d", i);
+				return;
+			}
+		}
+
+	yaffs_trace(YAFFS_TRACE_CHECKPOINT, "found no more checkpt blocks");
+
+	dev->checkpt_next_block = -1;
+	dev->checkpt_cur_block = -1;
+}
+
+int yaffs2_checkpt_open(struct yaffs_dev *dev, int writing)
+{
+	int i;
+
+	dev->checkpt_open_write = writing;
+
+	/* Got the functions we need? */
+	if (!dev->param.write_chunk_tags_fn ||
+	    !dev->param.read_chunk_tags_fn ||
+	    !dev->param.erase_fn || !dev->param.bad_block_fn)
+		return 0;
+
+	if (writing && !yaffs2_checkpt_space_ok(dev))
+		return 0;
+
+	if (!dev->checkpt_buffer)
+		dev->checkpt_buffer =
+		    kmalloc(dev->param.total_bytes_per_chunk, GFP_NOFS);
+	if (!dev->checkpt_buffer)
+		return 0;
+
+	dev->checkpt_page_seq = 0;
+	dev->checkpt_byte_count = 0;
+	dev->checkpt_sum = 0;
+	dev->checkpt_xor = 0;
+	dev->checkpt_cur_block = -1;
+	dev->checkpt_cur_chunk = -1;
+	dev->checkpt_next_block = dev->internal_start_block;
+
+	/* Erase all the blocks in the checkpoint area */
+	if (writing) {
+		memset(dev->checkpt_buffer, 0, dev->data_bytes_per_chunk);
+		dev->checkpt_byte_offs = 0;
+		return yaffs_checkpt_erase(dev);
+	}
+
+	/* Set to a value that will kick off a read */
+	dev->checkpt_byte_offs = dev->data_bytes_per_chunk;
+	/* A checkpoint block list of 1 checkpoint block per 16 block is
+	 * (hopefully) going to be way more than we need */
+	dev->blocks_in_checkpt = 0;
+	dev->checkpt_max_blocks =
+	    (dev->internal_end_block - dev->internal_start_block) / 16 + 2;
+	dev->checkpt_block_list =
+	    kmalloc(sizeof(int) * dev->checkpt_max_blocks, GFP_NOFS);
+
+	if (!dev->checkpt_block_list)
+		return 0;
+
+	for (i = 0; i < dev->checkpt_max_blocks; i++)
+		dev->checkpt_block_list[i] = -1;
+
+	return 1;
+}
+
+int yaffs2_get_checkpt_sum(struct yaffs_dev *dev, u32 * sum)
+{
+	u32 composite_sum;
+
+	composite_sum = (dev->checkpt_sum << 8) | (dev->checkpt_xor & 0xff);
+	*sum = composite_sum;
+	return 1;
+}
+
+static int yaffs2_checkpt_flush_buffer(struct yaffs_dev *dev)
+{
+	int chunk;
+	int realigned_chunk;
+	struct yaffs_ext_tags tags;
+
+	if (dev->checkpt_cur_block < 0) {
+		yaffs2_checkpt_find_erased_block(dev);
+		dev->checkpt_cur_chunk = 0;
+	}
+
+	if (dev->checkpt_cur_block < 0)
+		return 0;
+
+	tags.is_deleted = 0;
+	tags.obj_id = dev->checkpt_next_block;	/* Hint to next place to look */
+	tags.chunk_id = dev->checkpt_page_seq + 1;
+	tags.seq_number = YAFFS_SEQUENCE_CHECKPOINT_DATA;
+	tags.n_bytes = dev->data_bytes_per_chunk;
+	if (dev->checkpt_cur_chunk == 0) {
+		/* First chunk we write for the block? Set block state to
+		   checkpoint */
+		struct yaffs_block_info *bi =
+		    yaffs_get_block_info(dev, dev->checkpt_cur_block);
+		bi->block_state = YAFFS_BLOCK_STATE_CHECKPOINT;
+		dev->blocks_in_checkpt++;
+	}
+
+	chunk =
+	    dev->checkpt_cur_block * dev->param.chunks_per_block +
+	    dev->checkpt_cur_chunk;
+
+	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+		"checkpoint wite buffer nand %d(%d:%d) objid %d chId %d",
+		chunk, dev->checkpt_cur_block, dev->checkpt_cur_chunk,
+		tags.obj_id, tags.chunk_id);
+
+	realigned_chunk = chunk - dev->chunk_offset;
+
+	dev->n_page_writes++;
+
+	dev->param.write_chunk_tags_fn(dev, realigned_chunk,
+				       dev->checkpt_buffer, &tags);
+	dev->checkpt_byte_offs = 0;
+	dev->checkpt_page_seq++;
+	dev->checkpt_cur_chunk++;
+	if (dev->checkpt_cur_chunk >= dev->param.chunks_per_block) {
+		dev->checkpt_cur_chunk = 0;
+		dev->checkpt_cur_block = -1;
+	}
+	memset(dev->checkpt_buffer, 0, dev->data_bytes_per_chunk);
+
+	return 1;
+}
+
+int yaffs2_checkpt_wr(struct yaffs_dev *dev, const void *data, int n_bytes)
+{
+	int i = 0;
+	int ok = 1;
+	u8 *data_bytes = (u8 *) data;
+
+	if (!dev->checkpt_buffer)
+		return 0;
+
+	if (!dev->checkpt_open_write)
+		return -1;
+
+	while (i < n_bytes && ok) {
+		dev->checkpt_buffer[dev->checkpt_byte_offs] = *data_bytes;
+		dev->checkpt_sum += *data_bytes;
+		dev->checkpt_xor ^= *data_bytes;
+
+		dev->checkpt_byte_offs++;
+		i++;
+		data_bytes++;
+		dev->checkpt_byte_count++;
+
+		if (dev->checkpt_byte_offs < 0 ||
+		    dev->checkpt_byte_offs >= dev->data_bytes_per_chunk)
+			ok = yaffs2_checkpt_flush_buffer(dev);
+	}
+
+	return i;
+}
+
+int yaffs2_checkpt_rd(struct yaffs_dev *dev, void *data, int n_bytes)
+{
+	int i = 0;
+	int ok = 1;
+	struct yaffs_ext_tags tags;
+	int chunk;
+	int realigned_chunk;
+	u8 *data_bytes = (u8 *) data;
+
+	if (!dev->checkpt_buffer)
+		return 0;
+
+	if (dev->checkpt_open_write)
+		return -1;
+
+	while (i < n_bytes && ok) {
+
+		if (dev->checkpt_byte_offs < 0 ||
+		    dev->checkpt_byte_offs >= dev->data_bytes_per_chunk) {
+
+			if (dev->checkpt_cur_block < 0) {
+				yaffs2_checkpt_find_block(dev);
+				dev->checkpt_cur_chunk = 0;
+			}
+
+			if (dev->checkpt_cur_block < 0) {
+				ok = 0;
+				break;
+			}
+
+			chunk = dev->checkpt_cur_block *
+			    dev->param.chunks_per_block +
+			    dev->checkpt_cur_chunk;
+
+			realigned_chunk = chunk - dev->chunk_offset;
+			dev->n_page_reads++;
+
+			/* read in the next chunk */
+			dev->param.read_chunk_tags_fn(dev,
+						realigned_chunk,
+						dev->checkpt_buffer,
+						&tags);
+
+			if (tags.chunk_id != (dev->checkpt_page_seq + 1) ||
+			    tags.ecc_result > YAFFS_ECC_RESULT_FIXED ||
+			    tags.seq_number != YAFFS_SEQUENCE_CHECKPOINT_DATA) {
+				ok = 0;
+				break;
+			}
+
+			dev->checkpt_byte_offs = 0;
+			dev->checkpt_page_seq++;
+			dev->checkpt_cur_chunk++;
+
+			if (dev->checkpt_cur_chunk >=
+					dev->param.chunks_per_block)
+				dev->checkpt_cur_block = -1;
+		}
+
+		*data_bytes = dev->checkpt_buffer[dev->checkpt_byte_offs];
+		dev->checkpt_sum += *data_bytes;
+		dev->checkpt_xor ^= *data_bytes;
+		dev->checkpt_byte_offs++;
+		i++;
+		data_bytes++;
+		dev->checkpt_byte_count++;
+	}
+
+	return i;
+}
+
+int yaffs_checkpt_close(struct yaffs_dev *dev)
+{
+	int i;
+
+	if (dev->checkpt_open_write) {
+		if (dev->checkpt_byte_offs != 0)
+			yaffs2_checkpt_flush_buffer(dev);
+	} else if (dev->checkpt_block_list) {
+		for (i = 0;
+		     i < dev->blocks_in_checkpt &&
+		     dev->checkpt_block_list[i] >= 0; i++) {
+			int blk = dev->checkpt_block_list[i];
+			struct yaffs_block_info *bi = NULL;
+
+			if (dev->internal_start_block <= blk &&
+			    blk <= dev->internal_end_block)
+				bi = yaffs_get_block_info(dev, blk);
+			if (bi && bi->block_state == YAFFS_BLOCK_STATE_EMPTY)
+				bi->block_state = YAFFS_BLOCK_STATE_CHECKPOINT;
+		}
+		kfree(dev->checkpt_block_list);
+		dev->checkpt_block_list = NULL;
+	}
+
+	dev->n_free_chunks -=
+		dev->blocks_in_checkpt * dev->param.chunks_per_block;
+	dev->n_erased_blocks -= dev->blocks_in_checkpt;
+
+	yaffs_trace(YAFFS_TRACE_CHECKPOINT, "checkpoint byte count %d",
+		dev->checkpt_byte_count);
+
+	if (dev->checkpt_buffer) {
+		/* free the buffer */
+		kfree(dev->checkpt_buffer);
+		dev->checkpt_buffer = NULL;
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
+int yaffs2_checkpt_invalidate_stream(struct yaffs_dev *dev)
+{
+	/* Erase the checkpoint data */
+
+	yaffs_trace(YAFFS_TRACE_CHECKPOINT,
+		"checkpoint invalidate of %d blocks",
+		dev->blocks_in_checkpt);
+
+	return yaffs_checkpt_erase(dev);
+}
diff --git a/fs/yaffs2/yaffs_checkptrw.h b/fs/yaffs2/yaffs_checkptrw.h
new file mode 100644
index 0000000..cdbaba7
--- /dev/null
+++ b/fs/yaffs2/yaffs_checkptrw.h
@@ -0,0 +1,33 @@
+/*
+ * 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 Lesser General Public License version 2.1 as
+ * published by the Free Software Foundation.
+ *
+ * Note: Only YAFFS headers are LGPL, YAFFS C code is covered by GPL.
+ */
+
+#ifndef __YAFFS_CHECKPTRW_H__
+#define __YAFFS_CHECKPTRW_H__
+
+#include "yaffs_guts.h"
+
+int yaffs2_checkpt_open(struct yaffs_dev *dev, int writing);
+
+int yaffs2_checkpt_wr(struct yaffs_dev *dev, const void *data, int n_bytes);
+
+int yaffs2_checkpt_rd(struct yaffs_dev *dev, void *data, int n_bytes);
+
+int yaffs2_get_checkpt_sum(struct yaffs_dev *dev, u32 * sum);
+
+int yaffs_checkpt_close(struct yaffs_dev *dev);
+
+int yaffs2_checkpt_invalidate_stream(struct yaffs_dev *dev);
+
+#endif
-- 
1.7.1