Squashfs: Add LZO compression support

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

5 files changed, 149 insertions, 1 deletions

diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 3e9ee95ef37d..3da01108c44e 100644
--- a/fs/squashfs/Kconfig
+++ b/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" 
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index 6fa6b9deecd3..7672bac8d328 100644
--- a/fs/squashfs/Makefile
+++ b/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
diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c
index 157478da6ac9..24af9ce9722f 100644
--- a/fs/squashfs/decompressor.c
+++ b/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
 };
 
diff --git a/fs/squashfs/lzo_wrapper.c b/fs/squashfs/lzo_wrapper.c
new file mode 100644
index 000000000000..e1f86ded0ee5
--- /dev/null
+++ b/fs/squashfs/lzo_wrapper.c
@@ -0,0 +1,134 @@
+/*
+ * 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
+};
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index 733a17c42945..3a95ea68b00f 100644
--- a/fs/squashfs/squashfs.h
+++ b/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;