Signed-off-by: Enrico Jorns <[email protected]>
---
fs/squashfs/Kconfig | 13 +++++
fs/squashfs/Makefile | 1 +
fs/squashfs/lz4_wrapper.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 154 insertions(+)
create mode 100644 fs/squashfs/lz4_wrapper.c
diff --git a/fs/squashfs/Kconfig b/fs/squashfs/Kconfig
index d8ee554..d2de168 100644
--- a/fs/squashfs/Kconfig
+++ b/fs/squashfs/Kconfig
@@ -17,6 +17,19 @@ menuconfig FS_SQUASHFS
embedded systems where low overhead is needed. Further information
and tools are available from http://squashfs.sourceforge.net.
+config SQUASHFS_LZ4
+ bool "Include support for LZ4 compressed file systems"
+ depends on FS_SQUASHFS
+ select LZ4_DECOMPRESS
+ help
+ Saying Y here includes support for reading Squashfs file systems
+ compressed with LZ4 compression. LZ4 compression is mainly
+ aimed at embedded systems with slower CPUs where the overheads
+ of zlib are too high.
+
+ LZ4 is not the standard compression used in Squashfs and so most
+ file systems will be readable without selecting this option.
+
config SQUASHFS_LZO
bool "Include support for LZO compressed file systems"
default y
diff --git a/fs/squashfs/Makefile b/fs/squashfs/Makefile
index 447e15e..8590b09 100644
--- a/fs/squashfs/Makefile
+++ b/fs/squashfs/Makefile
@@ -12,3 +12,4 @@ obj-y += namei.o
obj-y += super.o
obj-$(CONFIG_SQUASHFS_XZ) += xz_wrapper.o
obj-$(CONFIG_SQUASHFS_LZO) += lzo_wrapper.o
+obj-$(CONFIG_SQUASHFS_LZ4) += lz4_wrapper.o
diff --git a/fs/squashfs/lz4_wrapper.c b/fs/squashfs/lz4_wrapper.c
new file mode 100644
index 0000000..6ca6a32
--- /dev/null
+++ b/fs/squashfs/lz4_wrapper.c
@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) 2013, 2014
+ * Phillip Lougher <[email protected]>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ */
+
+#include <types.h>
+#include <linux/mutex.h>
+#include <linux/lz4.h>
+
+#include "squashfs_fs.h"
+#include "squashfs_fs_sb.h"
+#include "squashfs.h"
+#include "decompressor.h"
+#include "page_actor.h"
+
+#define LZ4_LEGACY 1
+
+struct lz4_comp_opts {
+ __le32 version;
+ __le32 flags;
+};
+
+struct squashfs_lz4 {
+ void *input;
+ void *output;
+};
+
+
+static void *lz4_comp_opts(struct squashfs_sb_info *msblk,
+ void *buff, int len)
+{
+ struct lz4_comp_opts *comp_opts = buff;
+
+ /* LZ4 compressed filesystems always have compression options */
+ if (comp_opts == NULL || len < sizeof(*comp_opts))
+ return ERR_PTR(-EIO);
+
+ if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) {
+ /* LZ4 format currently used by the kernel is the 'legacy'
+ * format */
+ ERROR("Unknown LZ4 version\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ return NULL;
+}
+
+
+static void *lz4_init(struct squashfs_sb_info *msblk, void *buff)
+{
+ int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
+ struct squashfs_lz4 *stream;
+
+ stream = kzalloc(sizeof(*stream), GFP_KERNEL);
+ if (stream == NULL)
+ goto failed;
+ stream->input = vmalloc(block_size);
+ if (stream->input == NULL)
+ goto failed2;
+ stream->output = vmalloc(block_size);
+ if (stream->output == NULL)
+ goto failed3;
+
+ return stream;
+
+failed3:
+ vfree(stream->input);
+failed2:
+ kfree(stream);
+failed:
+ ERROR("Failed to initialise LZ4 decompressor\n");
+ return ERR_PTR(-ENOMEM);
+}
+
+
+static void lz4_free(void *strm)
+{
+ struct squashfs_lz4 *stream = strm;
+
+ if (stream) {
+ vfree(stream->input);
+ vfree(stream->output);
+ }
+ kfree(stream);
+}
+
+
+static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,
+ char **bh, int b, int offset, int length,
+ struct squashfs_page_actor *output)
+{
+ struct squashfs_lz4 *stream = strm;
+ void *buff = stream->input, *data;
+ int avail, i, bytes = length, res;
+ size_t dest_len = output->length;
+
+ for (i = 0; i < b; i++) {
+ avail = min(bytes, msblk->devblksize - offset);
+ memcpy(buff, bh[i] + offset, avail);
+ buff += avail;
+ bytes -= avail;
+ offset = 0;
+ kfree(bh[i]);
+ }
+
+ res = lz4_decompress_unknownoutputsize(stream->input, length,
+ stream->output, &dest_len);
+ if (res)
+ return -EIO;
+
+ bytes = dest_len;
+ data = squashfs_first_page(output);
+ buff = stream->output;
+ while (data) {
+ if (bytes <= PAGE_CACHE_SIZE) {
+ memcpy(data, buff, bytes);
+ break;
+ }
+ memcpy(data, buff, PAGE_CACHE_SIZE);
+ buff += PAGE_CACHE_SIZE;
+ bytes -= PAGE_CACHE_SIZE;
+ data = squashfs_next_page(output);
+ }
+ squashfs_finish_page(output);
+
+ return dest_len;
+}
+
+const struct squashfs_decompressor squashfs_lz4_comp_ops = {
+ .init = lz4_init,
+ .comp_opts = lz4_comp_opts,
+ .free = lz4_free,
+ .decompress = lz4_uncompress,
+ .id = LZ4_COMPRESSION,
+ .name = "lz4",
+ .supported = 1
+};
--
2.9.3
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