summaryrefslogtreecommitdiffstats
path: root/fs/btrfs/compression.c
blob: 59e4a94cb2e5ec6a813feab746c7fec900f6472c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
// SPDX-License-Identifier: GPL-2.0+
/*
 * BTRFS filesystem implementation for U-Boot
 *
 * 2017 Marek Behun, CZ.NIC, marek.behun@nic.cz
 */

#include "btrfs.h"
#include <log.h>
#include <malloc.h>
#include <linux/lzo.h>
#include <linux/zstd.h>
#include <linux/compat.h>
#include <u-boot/zlib.h>
#include <asm/unaligned.h>

/* Header for each segment, LE32, recording the compressed size */
#define LZO_LEN		4
static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
{
	u32 tot_len, tot_in, in_len, res;
	size_t out_len;
	int ret;

	if (clen < LZO_LEN)
		return -1;

	tot_len = le32_to_cpu(get_unaligned((u32 *)cbuf));
	tot_in = 0;
	cbuf += LZO_LEN;
	clen -= LZO_LEN;
	tot_len -= LZO_LEN;
	tot_in += LZO_LEN;

	if (tot_len == 0 && dlen)
		return -1;
	if (tot_len < LZO_LEN)
		return -1;

	res = 0;

	while (tot_len > LZO_LEN) {
		u32 rem_page;

		in_len = le32_to_cpu(get_unaligned((u32 *)cbuf));
		cbuf += LZO_LEN;
		clen -= LZO_LEN;

		if (in_len > clen || tot_len < LZO_LEN + in_len)
			return -1;

		tot_len -= (LZO_LEN + in_len);
		tot_in += (LZO_LEN + in_len);

		out_len = dlen;
		ret = lzo1x_decompress_safe(cbuf, in_len, dbuf, &out_len);
		if (ret != LZO_E_OK)
			return -1;

		cbuf += in_len;
		clen -= in_len;
		dbuf += out_len;
		dlen -= out_len;

		res += out_len;

		/*
		 * If the 4 bytes header does not fit to the rest of the page we
		 * have to move to next one, or we read some garbage.
		 */
		rem_page = PAGE_SIZE - (tot_in % PAGE_SIZE);
		if (rem_page < LZO_LEN) {
			cbuf += rem_page;
			tot_in += rem_page;
			clen -= rem_page;
			tot_len -= rem_page;
		}
	}

	return res;
}

/* from zutil.h */
#define PRESET_DICT 0x20

static u32 decompress_zlib(const u8 *_cbuf, u32 clen, u8 *dbuf, u32 dlen)
{
	int wbits = MAX_WBITS, ret = -1;
	z_stream stream;
	u8 *cbuf;
	u32 res;

	memset(&stream, 0, sizeof(stream));

	cbuf = (u8 *) _cbuf;

	stream.total_in = 0;

	stream.next_out = dbuf;
	stream.avail_out = dlen;
	stream.total_out = 0;

	/* skip adler32 check if deflate and no dictionary */
	if (clen > 2 && !(cbuf[1] & PRESET_DICT) &&
	    ((cbuf[0] & 0x0f) == Z_DEFLATED) &&
	    !(((cbuf[0] << 8) + cbuf[1]) % 31)) {
		wbits = -((cbuf[0] >> 4) + 8);
		cbuf += 2;
		clen -= 2;
	}

	if (Z_OK != inflateInit2(&stream, wbits))
		return -1;

	while (stream.total_in < clen) {
		stream.next_in = cbuf + stream.total_in;
		stream.avail_in = min((u32) (clen - stream.total_in),
				      (u32) btrfs_info.sb.sectorsize);

		ret = inflate(&stream, Z_NO_FLUSH);
		if (ret != Z_OK)
			break;
	}

	res = stream.total_out;
	inflateEnd(&stream);

	if (ret != Z_STREAM_END)
		return -1;

	return res;
}

#define ZSTD_BTRFS_MAX_WINDOWLOG 17
#define ZSTD_BTRFS_MAX_INPUT (1 << ZSTD_BTRFS_MAX_WINDOWLOG)

static u32 decompress_zstd(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
{
	ZSTD_DStream *dstream;
	ZSTD_inBuffer in_buf;
	ZSTD_outBuffer out_buf;
	void *workspace;
	size_t wsize;
	u32 res = -1;

	wsize = ZSTD_DStreamWorkspaceBound(ZSTD_BTRFS_MAX_INPUT);
	workspace = malloc(wsize);
	if (!workspace) {
		debug("%s: cannot allocate workspace of size %zu\n", __func__,
		      wsize);
		return -1;
	}

	dstream = ZSTD_initDStream(ZSTD_BTRFS_MAX_INPUT, workspace, wsize);
	if (!dstream) {
		printf("%s: ZSTD_initDStream failed\n", __func__);
		goto err_free;
	}

	in_buf.src = cbuf;
	in_buf.pos = 0;
	in_buf.size = clen;

	out_buf.dst = dbuf;
	out_buf.pos = 0;
	out_buf.size = dlen;

	while (1) {
		size_t ret;

		ret = ZSTD_decompressStream(dstream, &out_buf, &in_buf);
		if (ZSTD_isError(ret)) {
			printf("%s: ZSTD_decompressStream error %d\n", __func__,
			       ZSTD_getErrorCode(ret));
			goto err_free;
		}

		if (in_buf.pos >= clen || !ret)
			break;
	}

	res = out_buf.pos;

err_free:
	free(workspace);
	return res;
}

u32 btrfs_decompress(u8 type, const char *c, u32 clen, char *d, u32 dlen)
{
	u32 res;
	const u8 *cbuf;
	u8 *dbuf;

	cbuf = (const u8 *) c;
	dbuf = (u8 *) d;

	switch (type) {
	case BTRFS_COMPRESS_NONE:
		res = dlen < clen ? dlen : clen;
		memcpy(dbuf, cbuf, res);
		return res;
	case BTRFS_COMPRESS_ZLIB:
		return decompress_zlib(cbuf, clen, dbuf, dlen);
	case BTRFS_COMPRESS_LZO:
		return decompress_lzo(cbuf, clen, dbuf, dlen);
	case BTRFS_COMPRESS_ZSTD:
		return decompress_zstd(cbuf, clen, dbuf, dlen);
	default:
		printf("%s: Unsupported compression in extent: %i\n", __func__,
		       type);
		return -1;
	}
}