source: src/linux/universal/linux-4.9/fs/squashfs/lz4_wrapper.c @ 31630

Last change on this file since 31630 was 31630, checked in by brainslayer, 3 months ago

new fs is compatible with standard squashfs, just smaller

File size: 2.9 KB
Line 
1/*
2 * Copyright (c) 2013, 2014
3 * Phillip Lougher <phillip@squashfs.org.uk>
4 *
5 * This work is licensed under the terms of the GNU GPL, version 2. See
6 * the COPYING file in the top-level directory.
7 */
8
9#include <linux/buffer_head.h>
10#include <linux/mutex.h>
11#include <linux/slab.h>
12#include <linux/vmalloc.h>
13#include <linux/lz4.h>
14
15#include "squashfs_fs.h"
16#include "squashfs_fs_sb.h"
17#include "squashfs.h"
18#include "decompressor.h"
19#include "page_actor.h"
20
21#define LZ4_LEGACY      1
22
23struct lz4_comp_opts {
24        __le32 version;
25        __le32 flags;
26};
27
28struct squashfs_lz4 {
29        void *input;
30        void *output;
31};
32
33
34static void *lz4_comp_opts(struct squashfs_sb_info *msblk,
35        void *buff, int len)
36{
37        struct lz4_comp_opts *comp_opts = buff;
38
39        /* LZ4 compressed filesystems always have compression options */
40        if (comp_opts == NULL || len < sizeof(*comp_opts))
41                return ERR_PTR(-EIO);
42
43        if (le32_to_cpu(comp_opts->version) != LZ4_LEGACY) {
44                /* LZ4 format currently used by the kernel is the 'legacy'
45                 * format */
46                ERROR("Unknown LZ4 version\n");
47                return ERR_PTR(-EINVAL);
48        }
49
50        return NULL;
51}
52
53
54static void *lz4_init(struct squashfs_sb_info *msblk, void *buff)
55{
56        int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE);
57        struct squashfs_lz4 *stream;
58
59        stream = kzalloc(sizeof(*stream), GFP_KERNEL);
60        if (stream == NULL)
61                goto failed;
62        stream->input = vmalloc(block_size);
63        if (stream->input == NULL)
64                goto failed2;
65        stream->output = vmalloc(block_size);
66        if (stream->output == NULL)
67                goto failed3;
68
69        return stream;
70
71failed3:
72        vfree(stream->input);
73failed2:
74        kfree(stream);
75failed:
76        ERROR("Failed to initialise LZ4 decompressor\n");
77        return ERR_PTR(-ENOMEM);
78}
79
80
81static void lz4_free(void *strm)
82{
83        struct squashfs_lz4 *stream = strm;
84
85        if (stream) {
86                vfree(stream->input);
87                vfree(stream->output);
88        }
89        kfree(stream);
90}
91
92
93static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,
94        struct buffer_head **bh, int b, int offset, int length,
95        struct squashfs_page_actor *output)
96{
97        struct squashfs_lz4 *stream = strm;
98        void *buff = stream->input, *data;
99        int avail, i, bytes = length, res;
100        size_t dest_len = output->length;
101
102        for (i = 0; i < b; i++) {
103                avail = min(bytes, msblk->devblksize - offset);
104                memcpy(buff, bh[i]->b_data + offset, avail);
105                buff += avail;
106                bytes -= avail;
107                offset = 0;
108                put_bh(bh[i]);
109        }
110
111        res = lz4_decompress_unknownoutputsize(stream->input, length,
112                                        stream->output, &dest_len);
113        if (res)
114                return -EIO;
115
116        bytes = dest_len;
117        data = squashfs_first_page(output);
118        buff = stream->output;
119        while (data) {
120                if (bytes <= PAGE_SIZE) {
121                        memcpy(data, buff, bytes);
122                        break;
123                }
124                memcpy(data, buff, PAGE_SIZE);
125                buff += PAGE_SIZE;
126                bytes -= PAGE_SIZE;
127                data = squashfs_next_page(output);
128        }
129        squashfs_finish_page(output);
130
131        return dest_len;
132}
133
134const struct squashfs_decompressor squashfs_lz4_comp_ops = {
135        .init = lz4_init,
136        .comp_opts = lz4_comp_opts,
137        .free = lz4_free,
138        .decompress = lz4_uncompress,
139        .id = LZ4_COMPRESSION,
140        .name = "lz4",
141        .supported = 1
142};
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