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Subject[PATCH 6/9] Squashfs: add support for LZMA compressed filesystems
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Date

Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk>
---
fs/squashfs/Kconfig | 5 ++
fs/squashfs/Makefile | 1 +
fs/squashfs/decompressor.c | 4 +
fs/squashfs/lzma_wrapper.c | 151 ++++++++++++++++++++++++++++++++++++++++++++
fs/squashfs/squashfs.h | 3 +
5 files changed, 164 insertions(+), 0 deletions(-)
create mode 100644 fs/squashfs/lzma_wrapper.c

diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index 25a00d1..0294aa2 100644
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -26,6 +26,11 @@ config SQUASHFS

If unsure, say N.

+config SQUASHFS_LZMA
+ bool "Include support for LZMA compressed file systems"
+ depends on SQUASHFS
+ select DECOMPRESS_LZMA
+
config SQUASHFS_EMBEDDED

bool "Additional option for memory-constrained systems"
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index df8a19e..45aaefd 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -5,3 +5,4 @@
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_LZMA) += lzma_wrapper.o
diff --git a/fs/squashfs/decompressor.c b/fs/squashfs/decompressor.c
index 157478d..0b6ad9b 100644
--- a/fs/squashfs/decompressor.c
+++ b/fs/squashfs/decompressor.c
@@ -50,7 +50,11 @@ static const struct squashfs_decompressor squashfs_unknown_comp_ops = {

static const struct squashfs_decompressor *decompressor[] = {
&squashfs_zlib_comp_ops,
+#ifdef CONFIG_SQUASHFS_LZMA
+ &squashfs_lzma_comp_ops,
+#else
&squashfs_lzma_unsupported_comp_ops,
+#endif
&squashfs_lzo_unsupported_comp_ops,
&squashfs_unknown_comp_ops
};
diff --git a/fs/squashfs/lzma_wrapper.c b/fs/squashfs/lzma_wrapper.c
new file mode 100644
index 0000000..cef06d6
--- /dev/null
+++ b/fs/squashfs/lzma_wrapper.c
@@ -0,0 +1,151 @@
+/*
+ * Squashfs - a compressed read only filesystem for Linux
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+ * Phillip Lougher <phillip@lougher.demon.co.uk>
+ *
+ * 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.
+ *
+ * lzma_wrapper.c
+ */
+
+#include <asm/unaligned.h>
+#include <linux/buffer_head.h>
+#include <linux/mutex.h>
+#include <linux/vmalloc.h>
+#include <linux/decompress/unlzma.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs_fs_i.h"
+#include "squashfs.h"
+#include "decompressor.h"
+
+struct squashfs_lzma {
+ void *input;
+ void *output;
+};
+
+/* decompress_unlzma.c is currently non re-entrant... */
+DEFINE_MUTEX(lzma_mutex);
+
+/* decompress_unlzma.c doesn't provide any context in its callbacks... */
+static int lzma_error;
+
+static void error(char *m)
+{
+ ERROR("unlzma error: %s\n", m);
+ lzma_error = 1;
+}
+
+
+static void *lzma_init(struct squashfs_sb_info *msblk)
+{
+ struct squashfs_lzma *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 lzma workspace\n");
+ kfree(stream);
+ return NULL;
+}
+
+
+static void lzma_free(void *strm)
+{
+ struct squashfs_lzma *stream = strm;
+
+ if (stream) {
+ vfree(stream->input);
+ vfree(stream->output);
+ }
+ kfree(stream);
+}
+
+
+static int lzma_uncompress(struct squashfs_sb_info *msblk, void **buffer,
+ struct buffer_head **bh, int b, int offset, int length, int srclength,
+ int pages)
+{
+ struct squashfs_lzma *stream = msblk->stream;
+ void *buff = stream->input;
+ int avail, i, bytes = length, res;
+
+ mutex_lock(&lzma_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]);
+ }
+
+ lzma_error = 0;
+ res = unlzma(stream->input, length, NULL, NULL, stream->output, NULL,
+ error);
+ if (res || lzma_error)
+ goto failed;
+
+ /* uncompressed size is stored in the LZMA header (5 byte offset) */
+ res = bytes = get_unaligned_le32(stream->input + 5);
+ 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;
+ }
+ if (bytes)
+ goto failed;
+
+ mutex_unlock(&lzma_mutex);
+ return res;
+
+block_release:
+ for (; i < b; i++)
+ put_bh(bh[i]);
+
+failed:
+ mutex_unlock(&lzma_mutex);
+
+ ERROR("lzma decompression failed, data probably corrupt\n");
+ return -EIO;
+}
+
+const struct squashfs_decompressor squashfs_lzma_comp_ops = {
+ .init = lzma_init,
+ .free = lzma_free,
+ .decompress = lzma_uncompress,
+ .id = LZMA_COMPRESSION,
+ .name = "lzma",
+ .supported = 1
+};
+
diff --git a/fs/squashfs/squashfs.h b/fs/squashfs/squashfs.h
index fe2587a..d094886 100644
--- a/fs/squashfs/squashfs.h
+++ b/fs/squashfs/squashfs.h
@@ -94,3 +94,6 @@ extern const struct address_space_operations squashfs_symlink_aops;

/* zlib_wrapper.c */
extern const struct squashfs_decompressor squashfs_zlib_comp_ops;
+
+/* lzma wrapper.c */
+extern const struct squashfs_decompressor squashfs_lzma_comp_ops;
--
1.6.3.3


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