1 files changed, 173 insertions, 0 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
new file mode 100644
index 00000000000..c69524d38ec
--- /dev/null
+++ b/fs/btrfs/compression.c
@@ -0,0 +1,173 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * BTRFS filesystem implementation for U-Boot
+ *
+ * 2017 Marek Behún, CZ.NIC, kabel@kernel.org
+ */
+
+#include "btrfs.h"
+#include <abuf.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),
+					current_fs_info->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)
+{
+	struct abuf in, out;
+
+	abuf_init_set(&in, (u8 *)cbuf, clen);
+	abuf_init_set(&out, dbuf, dlen);
+
+	return zstd_decompress(&in, &out);
+}
+
+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;
+	}
+}