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fs: btrfs: add zstd decompression support 

This adds decompression support for Zstandard, which has been included
in Linux btrfs driver for some time.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
This commit is contained in:
Marek Behún 2019-04-29 22:40:45 +02:00 committed by Tom Rini
parent 8509f22aac
commit 53290e6efd
3 changed files with 63 additions and 2 deletions
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1
fs/btrfs/Kconfig
View File

@ -2,6 +2,7 @@ config FS_BTRFS
bool "Enable BTRFS filesystem support"
select CRC32C
select LZO
select ZSTD
select RBTREE
help
This provides a single-device read-only BTRFS support. BTRFS is a

5
fs/btrfs/btrfs_tree.h
View File

@ -647,8 +647,9 @@ enum btrfs_compression_type {
BTRFS_COMPRESS_NONE = 0,
BTRFS_COMPRESS_ZLIB = 1,
BTRFS_COMPRESS_LZO = 2,
BTRFS_COMPRESS_TYPES = 2,
BTRFS_COMPRESS_LAST = 3,
BTRFS_COMPRESS_ZSTD = 3,
BTRFS_COMPRESS_TYPES = 3,
BTRFS_COMPRESS_LAST = 4,
};
struct btrfs_file_extent_item {

59
fs/btrfs/compression.c
View File

@ -6,7 +6,9 @@
*/
#include "btrfs.h"
#include <malloc.h>
#include <linux/lzo.h>
#include <linux/zstd.h>
#include <u-boot/zlib.h>
#include <asm/unaligned.h>
@ -108,6 +110,61 @@ static u32 decompress_zlib(const u8 *_cbuf, u32 clen, u8 *dbuf, u32 dlen)
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;
@ -126,6 +183,8 @@ u32 btrfs_decompress(u8 type, const char *c, u32 clen, char *d, u32 dlen)
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);