mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
9c06a46f15
Add support for reading file systems compressed with the LZ4 compression algorithm. This patch adds the LZ4 decompressor wrapper code. Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
142 lines
3 KiB
C
142 lines
3 KiB
C
/*
|
|
* Copyright (c) 2013, 2014
|
|
* Phillip Lougher <phillip@squashfs.org.uk>
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2. See
|
|
* the COPYING file in the top-level directory.
|
|
*/
|
|
|
|
#include <linux/buffer_head.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/vmalloc.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,
|
|
struct buffer_head **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]->b_data + offset, avail);
|
|
buff += avail;
|
|
bytes -= avail;
|
|
offset = 0;
|
|
put_bh(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
|
|
};
|