Squashfs: Add LZO compression support

Signed-off-by: NChan Jeong <chan.jeong@lge.com>
Signed-off-by: NPhillip Lougher <phillip@lougher.demon.co.uk>

fs/squashfs/Kconfig

@@ -37,6 +37,11 @@ config SQUASHFS_XATTR
 
 	  If unsure, say N.
 
+config SQUASHFS_LZO
+	bool "Include support for LZO compressed file systems"
+	depends on SQUASHFS
+	select LZO_DECOMPRESS
+
 config SQUASHFS_EMBEDDED
 
 	bool "Additional option for memory-constrained systems" 

fs/squashfs/Makefile

@@ -6,4 +6,4 @@ obj-$(CONFIG_SQUASHFS) += squashfs.o
 squashfs-y += block.o cache.o dir.o export.o file.o fragment.o id.o inode.o
 squashfs-y += namei.o super.o symlink.o zlib_wrapper.o decompressor.o
 squashfs-$(CONFIG_SQUASHFS_XATTR) += xattr.o xattr_id.o
-
+squashfs-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o

fs/squashfs/decompressor.c

@@ -40,9 +40,11 @@ static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = {
 	NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0
 };
 
+#ifndef CONFIG_SQUASHFS_LZO
 static const struct squashfs_decompressor squashfs_lzo_unsupported_comp_ops = {
 	NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
 };
+#endif
 
 static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
 	NULL, NULL, NULL, 0, "unknown", 0
@@ -51,7 +53,11 @@ static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
 static const struct squashfs_decompressor *decompressor[] = {
 	&squashfs_zlib_comp_ops,
 	&squashfs_lzma_unsupported_comp_ops,
+#ifdef CONFIG_SQUASHFS_LZO
+	&squashfs_lzo_comp_ops,
+#else
 	&squashfs_lzo_unsupported_comp_ops,
+#endif
 	&squashfs_unknown_comp_ops
 };
 

fs/squashfs/lzo_wrapper.c

+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2010 LG Electronics
+ * Chan Jeong <chan.jeong@lge.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * lzo_wrapper.c
+ */
+
+#include <linux/mutex.h>
+#include <linux/buffer_head.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/lzo.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "decompressor.h"
+
+struct squashfs_lzo {
+	void	*input;
+	void	*output;
+};
+
+static void *lzo_init(struct squashfs_sb_info *msblk)
+{
+	struct squashfs_lzo *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
+	if (stream == NULL)
+		goto failed;
+	stream->input = vmalloc(msblk->block_size);
+	if (stream->input == NULL)
+		goto failed;
+	stream->output = vmalloc(msblk->block_size);
+	if (stream->output == NULL)
+		goto failed2;
+
+	return stream;
+
+failed2:
+	vfree(stream->input);
+failed:
+	ERROR("Failed to allocate lzo workspace\n");
+	kfree(stream);
+	return NULL;
+}
+
+
+static void lzo_free(void *strm)
+{
+	struct squashfs_lzo *stream = strm;
+
+	if (stream) {
+		vfree(stream->input);
+		vfree(stream->output);
+	}
+	kfree(stream);
+}
+
+
+static int lzo_uncompress(struct squashfs_sb_info *msblk, void **buffer,
+	struct buffer_head **bh, int b, int offset, int length, int srclength,
+	int pages)
+{
+	struct squashfs_lzo *stream = msblk->stream;
+	void *buff = stream->input;
+	int avail, i, bytes = length, res;
+	size_t out_len = msblk->block_size;
+
+	mutex_lock(&msblk->read_data_mutex);
+
+	for (i = 0; i < b; i++) {
+		wait_on_buffer(bh[i]);
+		if (!buffer_uptodate(bh[i]))
+			goto block_release;
+
+		avail = min(bytes, msblk->devblksize - offset);
+		memcpy(buff, bh[i]->b_data + offset, avail);
+		buff += avail;
+		bytes -= avail;
+		offset = 0;
+		put_bh(bh[i]);
+	}
+
+	res = lzo1x_decompress_safe(stream->input, (size_t)length,
+					stream->output, &out_len);
+	if (res != LZO_E_OK)
+		goto failed;
+
+	res = bytes = (int)out_len;
+	for (i = 0, buff = stream->output; bytes && i < pages; i++) {
+		avail = min_t(int, bytes, PAGE_CACHE_SIZE);
+		memcpy(buffer[i], buff, avail);
+		buff += avail;
+		bytes -= avail;
+	}
+
+	mutex_unlock(&msblk->read_data_mutex);
+	return res;
+
+block_release:
+	for (; i < b; i++)
+		put_bh(bh[i]);
+
+failed:
+	mutex_unlock(&msblk->read_data_mutex);
+
+	ERROR("lzo decompression failed, data probably corrupt\n");
+	return -EIO;
+}
+
+const struct squashfs_decompressor squashfs_lzo_comp_ops = {
+	.init = lzo_init,
+	.free = lzo_free,
+	.decompress = lzo_uncompress,
+	.id = LZO_COMPRESSION,
+	.name = "lzo",
+	.supported = 1
+};

fs/squashfs/squashfs.h

@@ -104,3 +104,6 @@ extern const struct xattr_handler *squashfs_xattr_handlers[];
 
 /* zlib_wrapper.c */
 extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
+
+/* lzo_wrappers.c */
+extern const struct squashfs_decompressor squashfs_lzo_comp_ops;